drivers/md/raid5.c

   1 /*
   2  * raid5.c : Multiple Devices driver for Linux
   3  *         Copyright (C) 1996, 1997 Ingo Molnar, Miguel de Icaza, Gadi Oxman
   4  *         Copyright (C) 1999, 2000 Ingo Molnar
   5  *         Copyright (C) 2002, 2003 H. Peter Anvin
   6  *
   7  * RAID-4/5/6 management functions.
   8  * Thanks to Penguin Computing for making the RAID-6 development possible
   9  * by donating a test server!
  10  *
  11  * This program is free software; you can redistribute it and/or modify
  12  * it under the terms of the GNU General Public License as published by
  13  * the Free Software Foundation; either version 2, or (at your option)
  14  * any later version.
  15  *
  16  * You should have received a copy of the GNU General Public License
  17  * (for example /usr/src/linux/COPYING); if not, write to the Free
  18  * Software Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
  19  */
  20
  21 /*
  22  * BITMAP UNPLUGGING:
  23  *
  24  * The sequencing for updating the bitmap reliably is a little
  25  * subtle (and I got it wrong the first time) so it deserves some
  26  * explanation.
  27  *
  28  * We group bitmap updates into batches.  Each batch has a number.
  29  * We may write out several batches at once, but that isn't very important.
  30  * conf->seq_write is the number of the last batch successfully written.
  31  * conf->seq_flush is the number of the last batch that was closed to
  32  *    new additions.
  33  * When we discover that we will need to write to any block in a stripe
  34  * (in add_stripe_bio) we update the in-memory bitmap and record in sh->bm_seq
  35  * the number of the batch it will be in. This is seq_flush+1.
  36  * When we are ready to do a write, if that batch hasn't been written yet,
  37  *   we plug the array and queue the stripe for later.
  38  * When an unplug happens, we increment bm_flush, thus closing the current
  39  *   batch.
  40  * When we notice that bm_flush > bm_write, we write out all pending updates
  41  * to the bitmap, and advance bm_write to where bm_flush was.
  42  * This may occasionally write a bit out twice, but is sure never to
  43  * miss any bits.
  44  */
  45
  46 #include <linux/blkdev.h>
  47 #include <linux/kthread.h>
  48 #include <linux/raid/pq.h>
  49 #include <linux/async_tx.h>
  50 #include <linux/module.h>
  51 #include <linux/async.h>
  52 #include <linux/seq_file.h>
  53 #include <linux/cpu.h>
  54 #include <linux/slab.h>
  55 #include <linux/ratelimit.h>
  56 #include <linux/nodemask.h>
  57 #include <linux/flex_array.h>
  58 #include <linux/sched/signal.h>
  59
  60 #include <trace/events/block.h>
  61 #include <linux/list_sort.h>
  62
  63 #include "md.h"
  64 #include "raid5.h"
  65 #include "raid0.h"
  66 #include "bitmap.h"
  67 #include "raid5-log.h"
  68
  69 #define UNSUPPORTED_MDDEV_FLAGS (1L << MD_FAILFAST_SUPPORTED)
  70
  71 #define cpu_to_group(cpu) cpu_to_node(cpu)
  72 #define ANY_GROUP NUMA_NO_NODE
  73
  74 static bool devices_handle_discard_safely = false;
  75 module_param(devices_handle_discard_safely, bool, 0644);
  76 MODULE_PARM_DESC(devices_handle_discard_safely,
  77                  "Set to Y if all devices in each array reliably return zeroes on reads from discarded regions");
  78 static struct workqueue_struct *raid5_wq;
  79
  80 static inline struct hlist_head *stripe_hash(struct r5conf *conf, sector_t sect)
  81 {
  82         int hash = (sect >> STRIPE_SHIFT) & HASH_MASK;
  83         return &conf->stripe_hashtbl[hash];
  84 }
  85
  86 static inline int stripe_hash_locks_hash(sector_t sect)
  87 {
  88         return (sect >> STRIPE_SHIFT) & STRIPE_HASH_LOCKS_MASK;
  89 }
  90
  91 static inline void lock_device_hash_lock(struct r5conf *conf, int hash)
  92 {
  93         spin_lock_irq(conf->hash_locks + hash);
  94         spin_lock(&conf->device_lock);
  95 }
  96
  97 static inline void unlock_device_hash_lock(struct r5conf *conf, int hash)
  98 {
  99         spin_unlock(&conf->device_lock);
 100         spin_unlock_irq(conf->hash_locks + hash);
 101 }
 102
 103 static inline void lock_all_device_hash_locks_irq(struct r5conf *conf)
 104 {
 105         int i;
 106         spin_lock_irq(conf->hash_locks);
 107         for (i = 1; i < NR_STRIPE_HASH_LOCKS; i++)
 108                 spin_lock_nest_lock(conf->hash_locks + i, conf->hash_locks);
 109         spin_lock(&conf->device_lock);
 110 }
 111
 112 static inline void unlock_all_device_hash_locks_irq(struct r5conf *conf)
 113 {
 114         int i;
 115         spin_unlock(&conf->device_lock);
 116         for (i = NR_STRIPE_HASH_LOCKS - 1; i; i--)
 117                 spin_unlock(conf->hash_locks + i);
 118         spin_unlock_irq(conf->hash_locks);
 119 }
 120
 121 /* Find first data disk in a raid6 stripe */
 122 static inline int raid6_d0(struct stripe_head *sh)
 123 {
 124         if (sh->ddf_layout)
 125                 /* ddf always start from first device */
 126                 return 0;
 127         /* md starts just after Q block */
 128         if (sh->qd_idx == sh->disks - 1)
 129                 return 0;
 130         else
 131                 return sh->qd_idx + 1;
 132 }
 133 static inline int raid6_next_disk(int disk, int raid_disks)
 134 {
 135         disk++;
 136         return (disk < raid_disks) ? disk : 0;
 137 }
 138
 139 /* When walking through the disks in a raid5, starting at raid6_d0,
 140  * We need to map each disk to a 'slot', where the data disks are slot
 141  * 0 .. raid_disks-3, the parity disk is raid_disks-2 and the Q disk
 142  * is raid_disks-1.  This help does that mapping.
 143  */
 144 static int raid6_idx_to_slot(int idx, struct stripe_head *sh,
 145                              int *count, int syndrome_disks)
 146 {
 147         int slot = *count;
 148
 149         if (sh->ddf_layout)
 150                 (*count)++;
 151         if (idx == sh->pd_idx)
 152                 return syndrome_disks;
 153         if (idx == sh->qd_idx)
 154                 return syndrome_disks + 1;
 155         if (!sh->ddf_layout)
 156                 (*count)++;
 157         return slot;
 158 }
 159
 160 static void print_raid5_conf (struct r5conf *conf);
 161
 162 static int stripe_operations_active(struct stripe_head *sh)
 163 {
 164         return sh->check_state || sh->reconstruct_state ||
 165                test_bit(STRIPE_BIOFILL_RUN, &sh->state) ||
 166                test_bit(STRIPE_COMPUTE_RUN, &sh->state);
 167 }
 168
 169 static bool stripe_is_lowprio(struct stripe_head *sh)
 170 {
 171         return (test_bit(STRIPE_R5C_FULL_STRIPE, &sh->state) ||
 172                 test_bit(STRIPE_R5C_PARTIAL_STRIPE, &sh->state)) &&
 173                !test_bit(STRIPE_R5C_CACHING, &sh->state);
 174 }
 175
 176 static void raid5_wakeup_stripe_thread(struct stripe_head *sh)
 177 {
 178         struct r5conf *conf = sh->raid_conf;
 179         struct r5worker_group *group;
 180         int thread_cnt;
 181         int i, cpu = sh->cpu;
 182
 183         if (!cpu_online(cpu)) {
 184                 cpu = cpumask_any(cpu_online_mask);
 185                 sh->cpu = cpu;
 186         }
 187
 188         if (list_empty(&sh->lru)) {
 189                 struct r5worker_group *group;
 190                 group = conf->worker_groups + cpu_to_group(cpu);
 191                 if (stripe_is_lowprio(sh))
 192                         list_add_tail(&sh->lru, &group->loprio_list);
 193                 else
 194                         list_add_tail(&sh->lru, &group->handle_list);
 195                 group->stripes_cnt++;
 196                 sh->group = group;
 197         }
 198
 199         if (conf->worker_cnt_per_group == 0) {
 200                 md_wakeup_thread(conf->mddev->thread);
 201                 return;
 202         }
 203
 204         group = conf->worker_groups + cpu_to_group(sh->cpu);
 205
 206         group->workers[0].working = true;
 207         /* at least one worker should run to avoid race */
 208         queue_work_on(sh->cpu, raid5_wq, &group->workers[0].work);
 209
 210         thread_cnt = group->stripes_cnt / MAX_STRIPE_BATCH - 1;
 211         /* wakeup more workers */
 212         for (i = 1; i < conf->worker_cnt_per_group && thread_cnt > 0; i++) {
 213                 if (group->workers[i].working == false) {
 214                         group->workers[i].working = true;
 215                         queue_work_on(sh->cpu, raid5_wq,
 216                                       &group->workers[i].work);
 217                         thread_cnt--;
 218                 }
 219         }
 220 }
 221
 222 static void do_release_stripe(struct r5conf *conf, struct stripe_head *sh,
 223                               struct list_head *temp_inactive_list)
 224 {
 225         int i;
 226         int injournal = 0;      /* number of date pages with R5_InJournal */
 227
 228         BUG_ON(!list_empty(&sh->lru));
 229         BUG_ON(atomic_read(&conf->active_stripes)==0);
 230
 231         if (r5c_is_writeback(conf->log))
 232                 for (i = sh->disks; i--; )
 233                         if (test_bit(R5_InJournal, &sh->dev[i].flags))
 234                                 injournal++;
 235         /*
 236          * In the following cases, the stripe cannot be released to cached
 237          * lists. Therefore, we make the stripe write out and set
 238          * STRIPE_HANDLE:
 239          *   1. when quiesce in r5c write back;
 240          *   2. when resync is requested fot the stripe.
 241          */
 242         if (test_bit(STRIPE_SYNC_REQUESTED, &sh->state) ||
 243             (conf->quiesce && r5c_is_writeback(conf->log) &&
 244              !test_bit(STRIPE_HANDLE, &sh->state) && injournal != 0)) {
 245                 if (test_bit(STRIPE_R5C_CACHING, &sh->state))
 246                         r5c_make_stripe_write_out(sh);
 247                 set_bit(STRIPE_HANDLE, &sh->state);
 248         }
 249
 250         if (test_bit(STRIPE_HANDLE, &sh->state)) {
 251                 if (test_bit(STRIPE_DELAYED, &sh->state) &&
 252                     !test_bit(STRIPE_PREREAD_ACTIVE, &sh->state))
 253                         list_add_tail(&sh->lru, &conf->delayed_list);
 254                 else if (test_bit(STRIPE_BIT_DELAY, &sh->state) &&
 255                            sh->bm_seq - conf->seq_write > 0)
 256                         list_add_tail(&sh->lru, &conf->bitmap_list);
 257                 else {
 258                         clear_bit(STRIPE_DELAYED, &sh->state);
 259                         clear_bit(STRIPE_BIT_DELAY, &sh->state);
 260                         if (conf->worker_cnt_per_group == 0) {
 261                                 if (stripe_is_lowprio(sh))
 262                                         list_add_tail(&sh->lru,
 263                                                         &conf->loprio_list);
 264                                 else
 265                                         list_add_tail(&sh->lru,
 266                                                         &conf->handle_list);
 267                         } else {
 268                                 raid5_wakeup_stripe_thread(sh);
 269                                 return;
 270                         }
 271                 }
 272                 md_wakeup_thread(conf->mddev->thread);
 273         } else {
 274                 BUG_ON(stripe_operations_active(sh));
 275                 if (test_and_clear_bit(STRIPE_PREREAD_ACTIVE, &sh->state))
 276                         if (atomic_dec_return(&conf->preread_active_stripes)
 277                             < IO_THRESHOLD)
 278                                 md_wakeup_thread(conf->mddev->thread);
 279                 atomic_dec(&conf->active_stripes);
 280                 if (!test_bit(STRIPE_EXPANDING, &sh->state)) {
 281                         if (!r5c_is_writeback(conf->log))
 282                                 list_add_tail(&sh->lru, temp_inactive_list);
 283                         else {
 284                                 WARN_ON(test_bit(R5_InJournal, &sh->dev[sh->pd_idx].flags));
 285                                 if (injournal == 0)
 286                                         list_add_tail(&sh->lru, temp_inactive_list);
 287                                 else if (injournal == conf->raid_disks - conf->max_degraded) {
 288                                         /* full stripe */
 289                                         if (!test_and_set_bit(STRIPE_R5C_FULL_STRIPE, &sh->state))
 290                                                 atomic_inc(&conf->r5c_cached_full_stripes);
 291                                         if (test_and_clear_bit(STRIPE_R5C_PARTIAL_STRIPE, &sh->state))
 292                                                 atomic_dec(&conf->r5c_cached_partial_stripes);
 293                                         list_add_tail(&sh->lru, &conf->r5c_full_stripe_list);
 294                                         r5c_check_cached_full_stripe(conf);
 295                                 } else
 296                                         /*
 297                                          * STRIPE_R5C_PARTIAL_STRIPE is set in
 298                                          * r5c_try_caching_write(). No need to
 299                                          * set it again.
 300                                          */
 301                                         list_add_tail(&sh->lru, &conf->r5c_partial_stripe_list);
 302                         }
 303                 }
 304         }
 305 }
 306
 307 static void __release_stripe(struct r5conf *conf, struct stripe_head *sh,
 308                              struct list_head *temp_inactive_list)
 309 {
 310         if (atomic_dec_and_test(&sh->count))
 311                 do_release_stripe(conf, sh, temp_inactive_list);
 312 }
 313
 314 /*
 315  * @hash could be NR_STRIPE_HASH_LOCKS, then we have a list of inactive_list
 316  *
 317  * Be careful: Only one task can add/delete stripes from temp_inactive_list at
 318  * given time. Adding stripes only takes device lock, while deleting stripes
 319  * only takes hash lock.
 320  */
 321 static void release_inactive_stripe_list(struct r5conf *conf,
 322                                          struct list_head *temp_inactive_list,
 323                                          int hash)
 324 {
 325         int size;
 326         bool do_wakeup = false;
 327         unsigned long flags;
 328
 329         if (hash == NR_STRIPE_HASH_LOCKS) {
 330                 size = NR_STRIPE_HASH_LOCKS;
 331                 hash = NR_STRIPE_HASH_LOCKS - 1;
 332         } else
 333                 size = 1;
 334         while (size) {
 335                 struct list_head *list = &temp_inactive_list[size - 1];
 336
 337                 /*
 338                  * We don't hold any lock here yet, raid5_get_active_stripe() might
 339                  * remove stripes from the list
 340                  */
 341                 if (!list_empty_careful(list)) {
 342                         spin_lock_irqsave(conf->hash_locks + hash, flags);
 343                         if (list_empty(conf->inactive_list + hash) &&
 344                             !list_empty(list))
 345                                 atomic_dec(&conf->empty_inactive_list_nr);
 346                         list_splice_tail_init(list, conf->inactive_list + hash);
 347                         do_wakeup = true;
 348                         spin_unlock_irqrestore(conf->hash_locks + hash, flags);
 349                 }
 350                 size--;
 351                 hash--;
 352         }
 353
 354         if (do_wakeup) {
 355                 wake_up(&conf->wait_for_stripe);
 356                 if (atomic_read(&conf->active_stripes) == 0)
 357                         wake_up(&conf->wait_for_quiescent);
 358                 if (conf->retry_read_aligned)
 359                         md_wakeup_thread(conf->mddev->thread);
 360         }
 361 }
 362
 363 /* should hold conf->device_lock already */
 364 static int release_stripe_list(struct r5conf *conf,
 365                                struct list_head *temp_inactive_list)
 366 {
 367         struct stripe_head *sh, *t;
 368         int count = 0;
 369         struct llist_node *head;
 370
 371         head = llist_del_all(&conf->released_stripes);
 372         head = llist_reverse_order(head);
 373         llist_for_each_entry_safe(sh, t, head, release_list) {
 374                 int hash;
 375
 376                 /* sh could be readded after STRIPE_ON_RELEASE_LIST is cleard */
 377                 smp_mb();
 378                 clear_bit(STRIPE_ON_RELEASE_LIST, &sh->state);
 379                 /*
 380                  * Don't worry the bit is set here, because if the bit is set
 381                  * again, the count is always > 1. This is true for
 382                  * STRIPE_ON_UNPLUG_LIST bit too.
 383                  */
 384                 hash = sh->hash_lock_index;
 385                 __release_stripe(conf, sh, &temp_inactive_list[hash]);
 386                 count++;
 387         }
 388
 389         return count;
 390 }
 391
 392 void raid5_release_stripe(struct stripe_head *sh)
 393 {
 394         struct r5conf *conf = sh->raid_conf;
 395         unsigned long flags;
 396         struct list_head list;
 397         int hash;
 398         bool wakeup;
 399
 400         /* Avoid release_list until the last reference.
 401          */
 402         if (atomic_add_unless(&sh->count, -1, 1))
 403                 return;
 404
 405         if (unlikely(!conf->mddev->thread) ||
 406                 test_and_set_bit(STRIPE_ON_RELEASE_LIST, &sh->state))
 407                 goto slow_path;
 408         wakeup = llist_add(&sh->release_list, &conf->released_stripes);
 409         if (wakeup)
 410                 md_wakeup_thread(conf->mddev->thread);
 411         return;
 412 slow_path:
 413         local_irq_save(flags);
 414         /* we are ok here if STRIPE_ON_RELEASE_LIST is set or not */
 415         if (atomic_dec_and_lock(&sh->count, &conf->device_lock)) {
 416                 INIT_LIST_HEAD(&list);
 417                 hash = sh->hash_lock_index;
 418                 do_release_stripe(conf, sh, &list);
 419                 spin_unlock(&conf->device_lock);
 420                 release_inactive_stripe_list(conf, &list, hash);
 421         }
 422         local_irq_restore(flags);
 423 }
 424
 425 static inline void remove_hash(struct stripe_head *sh)
 426 {
 427         pr_debug("remove_hash(), stripe %llu\n",
 428                 (unsigned long long)sh->sector);
 429
 430         hlist_del_init(&sh->hash);
 431 }
 432
 433 static inline void insert_hash(struct r5conf *conf, struct stripe_head *sh)
 434 {
 435         struct hlist_head *hp = stripe_hash(conf, sh->sector);
 436
 437         pr_debug("insert_hash(), stripe %llu\n",
 438                 (unsigned long long)sh->sector);
 439
 440         hlist_add_head(&sh->hash, hp);
 441 }
 442
 443 /* find an idle stripe, make sure it is unhashed, and return it. */
 444 static struct stripe_head *get_free_stripe(struct r5conf *conf, int hash)
 445 {
 446         struct stripe_head *sh = NULL;
 447         struct list_head *first;
 448
 449         if (list_empty(conf->inactive_list + hash))
 450                 goto out;
 451         first = (conf->inactive_list + hash)->next;
 452         sh = list_entry(first, struct stripe_head, lru);
 453         list_del_init(first);
 454         remove_hash(sh);
 455         atomic_inc(&conf->active_stripes);
 456         BUG_ON(hash != sh->hash_lock_index);
 457         if (list_empty(conf->inactive_list + hash))
 458                 atomic_inc(&conf->empty_inactive_list_nr);
 459 out:
 460         return sh;
 461 }
 462
 463 static void shrink_buffers(struct stripe_head *sh)
 464 {
 465         struct page *p;
 466         int i;
 467         int num = sh->raid_conf->pool_size;
 468
 469         for (i = 0; i < num ; i++) {
 470                 WARN_ON(sh->dev[i].page != sh->dev[i].orig_page);
 471                 p = sh->dev[i].page;
 472                 if (!p)
 473                         continue;
 474                 sh->dev[i].page = NULL;
 475                 put_page(p);
 476         }
 477 }
 478
 479 static int grow_buffers(struct stripe_head *sh, gfp_t gfp)
 480 {
 481         int i;
 482         int num = sh->raid_conf->pool_size;
 483
 484         for (i = 0; i < num; i++) {
 485                 struct page *page;
 486
 487                 if (!(page = alloc_page(gfp))) {
 488                         return 1;
 489                 }
 490                 sh->dev[i].page = page;
 491                 sh->dev[i].orig_page = page;
 492         }
 493
 494         return 0;
 495 }
 496
 497 static void stripe_set_idx(sector_t stripe, struct r5conf *conf, int previous,
 498                             struct stripe_head *sh);
 499
 500 static void init_stripe(struct stripe_head *sh, sector_t sector, int previous)
 501 {
 502         struct r5conf *conf = sh->raid_conf;
 503         int i, seq;
 504
 505         BUG_ON(atomic_read(&sh->count) != 0);
 506         BUG_ON(test_bit(STRIPE_HANDLE, &sh->state));
 507         BUG_ON(stripe_operations_active(sh));
 508         BUG_ON(sh->batch_head);
 509
 510         pr_debug("init_stripe called, stripe %llu\n",
 511                 (unsigned long long)sector);
 512 retry:
 513         seq = read_seqcount_begin(&conf->gen_lock);
 514         sh->generation = conf->generation - previous;
 515         sh->disks = previous ? conf->previous_raid_disks : conf->raid_disks;
 516         sh->sector = sector;
 517         stripe_set_idx(sector, conf, previous, sh);
 518         sh->state = 0;
 519
 520         for (i = sh->disks; i--; ) {
 521                 struct r5dev *dev = &sh->dev[i];
 522
 523                 if (dev->toread || dev->read || dev->towrite || dev->written ||
 524                     test_bit(R5_LOCKED, &dev->flags)) {
 525                         pr_err("sector=%llx i=%d %p %p %p %p %d\n",
 526                                (unsigned long long)sh->sector, i, dev->toread,
 527                                dev->read, dev->towrite, dev->written,
 528                                test_bit(R5_LOCKED, &dev->flags));
 529                         WARN_ON(1);
 530                 }
 531                 dev->flags = 0;
 532                 dev->sector = raid5_compute_blocknr(sh, i, previous);
 533         }
 534         if (read_seqcount_retry(&conf->gen_lock, seq))
 535                 goto retry;
 536         sh->overwrite_disks = 0;
 537         insert_hash(conf, sh);
 538         sh->cpu = smp_processor_id();
 539         set_bit(STRIPE_BATCH_READY, &sh->state);
 540 }
 541
 542 static struct stripe_head *__find_stripe(struct r5conf *conf, sector_t sector,
 543                                          short generation)
 544 {
 545         struct stripe_head *sh;
 546
 547         pr_debug("__find_stripe, sector %llu\n", (unsigned long long)sector);
 548         hlist_for_each_entry(sh, stripe_hash(conf, sector), hash)
 549                 if (sh->sector == sector && sh->generation == generation)
 550                         return sh;
 551         pr_debug("__stripe %llu not in cache\n", (unsigned long long)sector);
 552         return NULL;
 553 }
 554
 555 /*
 556  * Need to check if array has failed when deciding whether to:
 557  *  - start an array
 558  *  - remove non-faulty devices
 559  *  - add a spare
 560  *  - allow a reshape
 561  * This determination is simple when no reshape is happening.
 562  * However if there is a reshape, we need to carefully check
 563  * both the before and after sections.
 564  * This is because some failed devices may only affect one
 565  * of the two sections, and some non-in_sync devices may
 566  * be insync in the section most affected by failed devices.
 567  */
 568 int raid5_calc_degraded(struct r5conf *conf)
 569 {
 570         int degraded, degraded2;
 571         int i;
 572
 573         rcu_read_lock();
 574         degraded = 0;
 575         for (i = 0; i < conf->previous_raid_disks; i++) {
 576                 struct md_rdev *rdev = rcu_dereference(conf->disks[i].rdev);
 577                 if (rdev && test_bit(Faulty, &rdev->flags))
 578                         rdev = rcu_dereference(conf->disks[i].replacement);
 579                 if (!rdev || test_bit(Faulty, &rdev->flags))
 580                         degraded++;
 581                 else if (test_bit(In_sync, &rdev->flags))
 582                         ;
 583                 else
 584                         /* not in-sync or faulty.
 585                          * If the reshape increases the number of devices,
 586                          * this is being recovered by the reshape, so
 587                          * this 'previous' section is not in_sync.
 588                          * If the number of devices is being reduced however,
 589                          * the device can only be part of the array if
 590                          * we are reverting a reshape, so this section will
 591                          * be in-sync.
 592                          */
 593                         if (conf->raid_disks >= conf->previous_raid_disks)
 594                                 degraded++;
 595         }
 596         rcu_read_unlock();
 597         if (conf->raid_disks == conf->previous_raid_disks)
 598                 return degraded;
 599         rcu_read_lock();
 600         degraded2 = 0;
 601         for (i = 0; i < conf->raid_disks; i++) {
 602                 struct md_rdev *rdev = rcu_dereference(conf->disks[i].rdev);
 603                 if (rdev && test_bit(Faulty, &rdev->flags))
 604                         rdev = rcu_dereference(conf->disks[i].replacement);
 605                 if (!rdev || test_bit(Faulty, &rdev->flags))
 606                         degraded2++;
 607                 else if (test_bit(In_sync, &rdev->flags))
 608                         ;
 609                 else
 610                         /* not in-sync or faulty.
 611                          * If reshape increases the number of devices, this
 612                          * section has already been recovered, else it
 613                          * almost certainly hasn't.
 614                          */
 615                         if (conf->raid_disks <= conf->previous_raid_disks)
 616                                 degraded2++;
 617         }
 618         rcu_read_unlock();
 619         if (degraded2 > degraded)
 620                 return degraded2;
 621         return degraded;
 622 }
 623
 624 static int has_failed(struct r5conf *conf)
 625 {
 626         int degraded;
 627
 628         if (conf->mddev->reshape_position == MaxSector)
 629                 return conf->mddev->degraded > conf->max_degraded;
 630
 631         degraded = raid5_calc_degraded(conf);
 632         if (degraded > conf->max_degraded)
 633                 return 1;
 634         return 0;
 635 }
 636
 637 struct stripe_head *
 638 raid5_get_active_stripe(struct r5conf *conf, sector_t sector,
 639                         int previous, int noblock, int noquiesce)
 640 {
 641         struct stripe_head *sh;
 642         int hash = stripe_hash_locks_hash(sector);
 643         int inc_empty_inactive_list_flag;
 644
 645         pr_debug("get_stripe, sector %llu\n", (unsigned long long)sector);
 646
 647         spin_lock_irq(conf->hash_locks + hash);
 648
 649         do {
 650                 wait_event_lock_irq(conf->wait_for_quiescent,
 651                                     conf->quiesce == 0 || noquiesce,
 652                                     *(conf->hash_locks + hash));
 653                 sh = __find_stripe(conf, sector, conf->generation - previous);
 654                 if (!sh) {
 655                         if (!test_bit(R5_INACTIVE_BLOCKED, &conf->cache_state)) {
 656                                 sh = get_free_stripe(conf, hash);
 657                                 if (!sh && !test_bit(R5_DID_ALLOC,
 658                                                      &conf->cache_state))
 659                                         set_bit(R5_ALLOC_MORE,
 660                                                 &conf->cache_state);
 661                         }
 662                         if (noblock && sh == NULL)
 663                                 break;
 664
 665                         r5c_check_stripe_cache_usage(conf);
 666                         if (!sh) {
 667                                 set_bit(R5_INACTIVE_BLOCKED,
 668                                         &conf->cache_state);
 669                                 r5l_wake_reclaim(conf->log, 0);
 670                                 wait_event_lock_irq(
 671                                         conf->wait_for_stripe,
 672                                         !list_empty(conf->inactive_list + hash) &&
 673                                         (atomic_read(&conf->active_stripes)
 674                                          < (conf->max_nr_stripes * 3 / 4)
 675                                          || !test_bit(R5_INACTIVE_BLOCKED,
 676                                                       &conf->cache_state)),
 677                                         *(conf->hash_locks + hash));
 678                                 clear_bit(R5_INACTIVE_BLOCKED,
 679                                           &conf->cache_state);
 680                         } else {
 681                                 init_stripe(sh, sector, previous);
 682                                 atomic_inc(&sh->count);
 683                         }
 684                 } else if (!atomic_inc_not_zero(&sh->count)) {
 685                         spin_lock(&conf->device_lock);
 686                         if (!atomic_read(&sh->count)) {
 687                                 if (!test_bit(STRIPE_HANDLE, &sh->state))
 688                                         atomic_inc(&conf->active_stripes);
 689                                 BUG_ON(list_empty(&sh->lru) &&
 690                                        !test_bit(STRIPE_EXPANDING, &sh->state));
 691                                 inc_empty_inactive_list_flag = 0;
 692                                 if (!list_empty(conf->inactive_list + hash))
 693                                         inc_empty_inactive_list_flag = 1;
 694                                 list_del_init(&sh->lru);
 695                                 if (list_empty(conf->inactive_list + hash) && inc_empty_inactive_list_flag)
 696                                         atomic_inc(&conf->empty_inactive_list_nr);
 697                                 if (sh->group) {
 698                                         sh->group->stripes_cnt--;
 699                                         sh->group = NULL;
 700                                 }
 701                         }
 702                         atomic_inc(&sh->count);
 703                         spin_unlock(&conf->device_lock);
 704                 }
 705         } while (sh == NULL);
 706
 707         spin_unlock_irq(conf->hash_locks + hash);
 708         return sh;
 709 }
 710
 711 static bool is_full_stripe_write(struct stripe_head *sh)
 712 {
 713         BUG_ON(sh->overwrite_disks > (sh->disks - sh->raid_conf->max_degraded));
 714         return sh->overwrite_disks == (sh->disks - sh->raid_conf->max_degraded);
 715 }
 716
 717 static void lock_two_stripes(struct stripe_head *sh1, struct stripe_head *sh2)
 718 {
 719         if (sh1 > sh2) {
 720                 spin_lock_irq(&sh2->stripe_lock);
 721                 spin_lock_nested(&sh1->stripe_lock, 1);
 722         } else {
 723                 spin_lock_irq(&sh1->stripe_lock);
 724                 spin_lock_nested(&sh2->stripe_lock, 1);
 725         }
 726 }
 727
 728 static void unlock_two_stripes(struct stripe_head *sh1, struct stripe_head *sh2)
 729 {
 730         spin_unlock(&sh1->stripe_lock);
 731         spin_unlock_irq(&sh2->stripe_lock);
 732 }
 733
 734 /* Only freshly new full stripe normal write stripe can be added to a batch list */
 735 static bool stripe_can_batch(struct stripe_head *sh)
 736 {
 737         struct r5conf *conf = sh->raid_conf;
 738
 739         if (conf->log || raid5_has_ppl(conf))
 740                 return false;
 741         return test_bit(STRIPE_BATCH_READY, &sh->state) &&
 742                 !test_bit(STRIPE_BITMAP_PENDING, &sh->state) &&
 743                 is_full_stripe_write(sh);
 744 }
 745
 746 /* we only do back search */
 747 static void stripe_add_to_batch_list(struct r5conf *conf, struct stripe_head *sh)
 748 {
 749         struct stripe_head *head;
 750         sector_t head_sector, tmp_sec;
 751         int hash;
 752         int dd_idx;
 753         int inc_empty_inactive_list_flag;
 754
 755         /* Don't cross chunks, so stripe pd_idx/qd_idx is the same */
 756         tmp_sec = sh->sector;
 757         if (!sector_div(tmp_sec, conf->chunk_sectors))
 758                 return;
 759         head_sector = sh->sector - STRIPE_SECTORS;
 760
 761         hash = stripe_hash_locks_hash(head_sector);
 762         spin_lock_irq(conf->hash_locks + hash);
 763         head = __find_stripe(conf, head_sector, conf->generation);
 764         if (head && !atomic_inc_not_zero(&head->count)) {
 765                 spin_lock(&conf->device_lock);
 766                 if (!atomic_read(&head->count)) {
 767                         if (!test_bit(STRIPE_HANDLE, &head->state))
 768                                 atomic_inc(&conf->active_stripes);
 769                         BUG_ON(list_empty(&head->lru) &&
 770                                !test_bit(STRIPE_EXPANDING, &head->state));
 771                         inc_empty_inactive_list_flag = 0;
 772                         if (!list_empty(conf->inactive_list + hash))
 773                                 inc_empty_inactive_list_flag = 1;
 774                         list_del_init(&head->lru);
 775                         if (list_empty(conf->inactive_list + hash) && inc_empty_inactive_list_flag)
 776                                 atomic_inc(&conf->empty_inactive_list_nr);
 777                         if (head->group) {
 778                                 head->group->stripes_cnt--;
 779                                 head->group = NULL;
 780                         }
 781                 }
 782                 atomic_inc(&head->count);
 783                 spin_unlock(&conf->device_lock);
 784         }
 785         spin_unlock_irq(conf->hash_locks + hash);
 786
 787         if (!head)
 788                 return;
 789         if (!stripe_can_batch(head))
 790                 goto out;
 791
 792         lock_two_stripes(head, sh);
 793         /* clear_batch_ready clear the flag */
 794         if (!stripe_can_batch(head) || !stripe_can_batch(sh))
 795                 goto unlock_out;
 796
 797         if (sh->batch_head)
 798                 goto unlock_out;
 799
 800         dd_idx = 0;
 801         while (dd_idx == sh->pd_idx || dd_idx == sh->qd_idx)
 802                 dd_idx++;
 803         if (head->dev[dd_idx].towrite->bi_opf != sh->dev[dd_idx].towrite->bi_opf ||
 804             bio_op(head->dev[dd_idx].towrite) != bio_op(sh->dev[dd_idx].towrite))
 805                 goto unlock_out;
 806
 807         if (head->batch_head) {
 808                 spin_lock(&head->batch_head->batch_lock);
 809                 /* This batch list is already running */
 810                 if (!stripe_can_batch(head)) {
 811                         spin_unlock(&head->batch_head->batch_lock);
 812                         goto unlock_out;
 813                 }
 814                 /*
 815                  * We must assign batch_head of this stripe within the
 816                  * batch_lock, otherwise clear_batch_ready of batch head
 817                  * stripe could clear BATCH_READY bit of this stripe and
 818                  * this stripe->batch_head doesn't get assigned, which
 819                  * could confuse clear_batch_ready for this stripe
 820                  */
 821                 sh->batch_head = head->batch_head;
 822
 823                 /*
 824                  * at this point, head's BATCH_READY could be cleared, but we
 825                  * can still add the stripe to batch list
 826                  */
 827                 list_add(&sh->batch_list, &head->batch_list);
 828                 spin_unlock(&head->batch_head->batch_lock);
 829         } else {
 830                 head->batch_head = head;
 831                 sh->batch_head = head->batch_head;
 832                 spin_lock(&head->batch_lock);
 833                 list_add_tail(&sh->batch_list, &head->batch_list);
 834                 spin_unlock(&head->batch_lock);
 835         }
 836
 837         if (test_and_clear_bit(STRIPE_PREREAD_ACTIVE, &sh->state))
 838                 if (atomic_dec_return(&conf->preread_active_stripes)
 839                     < IO_THRESHOLD)
 840                         md_wakeup_thread(conf->mddev->thread);
 841
 842         if (test_and_clear_bit(STRIPE_BIT_DELAY, &sh->state)) {
 843                 int seq = sh->bm_seq;
 844                 if (test_bit(STRIPE_BIT_DELAY, &sh->batch_head->state) &&
 845                     sh->batch_head->bm_seq > seq)
 846                         seq = sh->batch_head->bm_seq;
 847                 set_bit(STRIPE_BIT_DELAY, &sh->batch_head->state);
 848                 sh->batch_head->bm_seq = seq;
 849         }
 850
 851         atomic_inc(&sh->count);
 852 unlock_out:
 853         unlock_two_stripes(head, sh);
 854 out:
 855         raid5_release_stripe(head);
 856 }
 857
 858 /* Determine if 'data_offset' or 'new_data_offset' should be used
 859  * in this stripe_head.
 860  */
 861 static int use_new_offset(struct r5conf *conf, struct stripe_head *sh)
 862 {
 863         sector_t progress = conf->reshape_progress;
 864         /* Need a memory barrier to make sure we see the value
 865          * of conf->generation, or ->data_offset that was set before
 866          * reshape_progress was updated.
 867          */
 868         smp_rmb();
 869         if (progress == MaxSector)
 870                 return 0;
 871         if (sh->generation == conf->generation - 1)
 872                 return 0;
 873         /* We are in a reshape, and this is a new-generation stripe,
 874          * so use new_data_offset.
 875          */
 876         return 1;
 877 }
 878
 879 static void dispatch_bio_list(struct bio_list *tmp)
 880 {
 881         struct bio *bio;
 882
 883         while ((bio = bio_list_pop(tmp)))
 884                 generic_make_request(bio);
 885 }
 886
 887 static int cmp_stripe(void *priv, struct list_head *a, struct list_head *b)
 888 {
 889         const struct r5pending_data *da = list_entry(a,
 890                                 struct r5pending_data, sibling);
 891         const struct r5pending_data *db = list_entry(b,
 892                                 struct r5pending_data, sibling);
 893         if (da->sector > db->sector)
 894                 return 1;
 895         if (da->sector < db->sector)
 896                 return -1;
 897         return 0;
 898 }
 899
 900 static void dispatch_defer_bios(struct r5conf *conf, int target,
 901                                 struct bio_list *list)
 902 {
 903         struct r5pending_data *data;
 904         struct list_head *first, *next = NULL;
 905         int cnt = 0;
 906
 907         if (conf->pending_data_cnt == 0)
 908                 return;
 909
 910         list_sort(NULL, &conf->pending_list, cmp_stripe);
 911
 912         first = conf->pending_list.next;
 913
 914         /* temporarily move the head */
 915         if (conf->next_pending_data)
 916                 list_move_tail(&conf->pending_list,
 917                                 &conf->next_pending_data->sibling);
 918
 919         while (!list_empty(&conf->pending_list)) {
 920                 data = list_first_entry(&conf->pending_list,
 921                         struct r5pending_data, sibling);
 922                 if (&data->sibling == first)
 923                         first = data->sibling.next;
 924                 next = data->sibling.next;
 925
 926                 bio_list_merge(list, &data->bios);
 927                 list_move(&data->sibling, &conf->free_list);
 928                 cnt++;
 929                 if (cnt >= target)
 930                         break;
 931         }
 932         conf->pending_data_cnt -= cnt;
 933         BUG_ON(conf->pending_data_cnt < 0 || cnt < target);
 934
 935         if (next != &conf->pending_list)
 936                 conf->next_pending_data = list_entry(next,
 937                                 struct r5pending_data, sibling);
 938         else
 939                 conf->next_pending_data = NULL;
 940         /* list isn't empty */
 941         if (first != &conf->pending_list)
 942                 list_move_tail(&conf->pending_list, first);
 943 }
 944
 945 static void flush_deferred_bios(struct r5conf *conf)
 946 {
 947         struct bio_list tmp = BIO_EMPTY_LIST;
 948
 949         if (conf->pending_data_cnt == 0)
 950                 return;
 951
 952         spin_lock(&conf->pending_bios_lock);
 953         dispatch_defer_bios(conf, conf->pending_data_cnt, &tmp);
 954         BUG_ON(conf->pending_data_cnt != 0);
 955         spin_unlock(&conf->pending_bios_lock);
 956
 957         dispatch_bio_list(&tmp);
 958 }
 959
 960 static void defer_issue_bios(struct r5conf *conf, sector_t sector,
 961                                 struct bio_list *bios)
 962 {
 963         struct bio_list tmp = BIO_EMPTY_LIST;
 964         struct r5pending_data *ent;
 965
 966         spin_lock(&conf->pending_bios_lock);
 967         ent = list_first_entry(&conf->free_list, struct r5pending_data,
 968                                                         sibling);
 969         list_move_tail(&ent->sibling, &conf->pending_list);
 970         ent->sector = sector;
 971         bio_list_init(&ent->bios);
 972         bio_list_merge(&ent->bios, bios);
 973         conf->pending_data_cnt++;
 974         if (conf->pending_data_cnt >= PENDING_IO_MAX)
 975                 dispatch_defer_bios(conf, PENDING_IO_ONE_FLUSH, &tmp);
 976
 977         spin_unlock(&conf->pending_bios_lock);
 978
 979         dispatch_bio_list(&tmp);
 980 }
 981
 982 static void
 983 raid5_end_read_request(struct bio *bi);
 984 static void
 985 raid5_end_write_request(struct bio *bi);
 986
 987 static void ops_run_io(struct stripe_head *sh, struct stripe_head_state *s)
 988 {
 989         struct r5conf *conf = sh->raid_conf;
 990         int i, disks = sh->disks;
 991         struct stripe_head *head_sh = sh;
 992         struct bio_list pending_bios = BIO_EMPTY_LIST;
 993         bool should_defer;
 994
 995         might_sleep();
 996
 997         if (log_stripe(sh, s) == 0)
 998                 return;
 999
1000         should_defer = conf->batch_bio_dispatch && conf->group_cnt;
1001
1002         for (i = disks; i--; ) {
1003                 int op, op_flags = 0;
1004                 int replace_only = 0;
1005                 struct bio *bi, *rbi;
1006                 struct md_rdev *rdev, *rrdev = NULL;
1007
1008                 sh = head_sh;
1009                 if (test_and_clear_bit(R5_Wantwrite, &sh->dev[i].flags)) {
1010                         op = REQ_OP_WRITE;
1011                         if (test_and_clear_bit(R5_WantFUA, &sh->dev[i].flags))
1012                                 op_flags = REQ_FUA;
1013                         if (test_bit(R5_Discard, &sh->dev[i].flags))
1014                                 op = REQ_OP_DISCARD;
1015                 } else if (test_and_clear_bit(R5_Wantread, &sh->dev[i].flags))
1016                         op = REQ_OP_READ;
1017                 else if (test_and_clear_bit(R5_WantReplace,
1018                                             &sh->dev[i].flags)) {
1019                         op = REQ_OP_WRITE;
1020                         replace_only = 1;
1021                 } else
1022                         continue;
1023                 if (test_and_clear_bit(R5_SyncIO, &sh->dev[i].flags))
1024                         op_flags |= REQ_SYNC;
1025
1026 again:
1027                 bi = &sh->dev[i].req;
1028                 rbi = &sh->dev[i].rreq; /* For writing to replacement */
1029
1030                 rcu_read_lock();
1031                 rrdev = rcu_dereference(conf->disks[i].replacement);
1032                 smp_mb(); /* Ensure that if rrdev is NULL, rdev won't be */
1033                 rdev = rcu_dereference(conf->disks[i].rdev);
1034                 if (!rdev) {
1035                         rdev = rrdev;
1036                         rrdev = NULL;
1037                 }
1038                 if (op_is_write(op)) {
1039                         if (replace_only)
1040                                 rdev = NULL;
1041                         if (rdev == rrdev)
1042                                 /* We raced and saw duplicates */
1043                                 rrdev = NULL;
1044                 } else {
1045                         if (test_bit(R5_ReadRepl, &head_sh->dev[i].flags) && rrdev)
1046                                 rdev = rrdev;
1047                         rrdev = NULL;
1048                 }
1049
1050                 if (rdev && test_bit(Faulty, &rdev->flags))
1051                         rdev = NULL;
1052                 if (rdev)
1053                         atomic_inc(&rdev->nr_pending);
1054                 if (rrdev && test_bit(Faulty, &rrdev->flags))
1055                         rrdev = NULL;
1056                 if (rrdev)
1057                         atomic_inc(&rrdev->nr_pending);
1058                 rcu_read_unlock();
1059
1060                 /* We have already checked bad blocks for reads.  Now
1061                  * need to check for writes.  We never accept write errors
1062                  * on the replacement, so we don't to check rrdev.
1063                  */
1064                 while (op_is_write(op) && rdev &&
1065                        test_bit(WriteErrorSeen, &rdev->flags)) {
1066                         sector_t first_bad;
1067                         int bad_sectors;
1068                         int bad = is_badblock(rdev, sh->sector, STRIPE_SECTORS,
1069                                               &first_bad, &bad_sectors);
1070                         if (!bad)
1071                                 break;
1072
1073                         if (bad < 0) {
1074                                 set_bit(BlockedBadBlocks, &rdev->flags);
1075                                 if (!conf->mddev->external &&
1076                                     conf->mddev->sb_flags) {
1077                                         /* It is very unlikely, but we might
1078                                          * still need to write out the
1079                                          * bad block log - better give it
1080                                          * a chance*/
1081                                         md_check_recovery(conf->mddev);
1082                                 }
1083                                 /*
1084                                  * Because md_wait_for_blocked_rdev
1085                                  * will dec nr_pending, we must
1086                                  * increment it first.
1087                                  */
1088                                 atomic_inc(&rdev->nr_pending);
1089                                 md_wait_for_blocked_rdev(rdev, conf->mddev);
1090                         } else {
1091                                 /* Acknowledged bad block - skip the write */
1092                                 rdev_dec_pending(rdev, conf->mddev);
1093                                 rdev = NULL;
1094                         }
1095                 }
1096
1097                 if (rdev) {
1098                         if (s->syncing || s->expanding || s->expanded
1099                             || s->replacing)
1100                                 md_sync_acct(rdev->bdev, STRIPE_SECTORS);
1101
1102                         set_bit(STRIPE_IO_STARTED, &sh->state);
1103
1104                         bio_set_dev(bi, rdev->bdev);
1105                         bio_set_op_attrs(bi, op, op_flags);
1106                         bi->bi_end_io = op_is_write(op)
1107                                 ? raid5_end_write_request
1108                                 : raid5_end_read_request;
1109                         bi->bi_private = sh;
1110
1111                         pr_debug("%s: for %llu schedule op %d on disc %d\n",
1112                                 __func__, (unsigned long long)sh->sector,
1113                                 bi->bi_opf, i);
1114                         atomic_inc(&sh->count);
1115                         if (sh != head_sh)
1116                                 atomic_inc(&head_sh->count);
1117                         if (use_new_offset(conf, sh))
1118                                 bi->bi_iter.bi_sector = (sh->sector
1119                                                  + rdev->new_data_offset);
1120                         else
1121                                 bi->bi_iter.bi_sector = (sh->sector
1122                                                  + rdev->data_offset);
1123                         if (test_bit(R5_ReadNoMerge, &head_sh->dev[i].flags))
1124                                 bi->bi_opf |= REQ_NOMERGE;
1125
1126                         if (test_bit(R5_SkipCopy, &sh->dev[i].flags))
1127                                 WARN_ON(test_bit(R5_UPTODATE, &sh->dev[i].flags));
1128
1129                         if (!op_is_write(op) &&
1130                             test_bit(R5_InJournal, &sh->dev[i].flags))
1131                                 /*
1132                                  * issuing read for a page in journal, this
1133                                  * must be preparing for prexor in rmw; read
1134                                  * the data into orig_page
1135                                  */
1136                                 sh->dev[i].vec.bv_page = sh->dev[i].orig_page;
1137                         else
1138                                 sh->dev[i].vec.bv_page = sh->dev[i].page;
1139                         bi->bi_vcnt = 1;
1140                         bi->bi_io_vec[0].bv_len = STRIPE_SIZE;
1141                         bi->bi_io_vec[0].bv_offset = 0;
1142                         bi->bi_iter.bi_size = STRIPE_SIZE;
1143                         /*
1144                          * If this is discard request, set bi_vcnt 0. We don't
1145                          * want to confuse SCSI because SCSI will replace payload
1146                          */
1147                         if (op == REQ_OP_DISCARD)
1148                                 bi->bi_vcnt = 0;
1149                         if (rrdev)
1150                                 set_bit(R5_DOUBLE_LOCKED, &sh->dev[i].flags);
1151
1152                         if (conf->mddev->gendisk)
1153                                 trace_block_bio_remap(bi->bi_disk->queue,
1154                                                       bi, disk_devt(conf->mddev->gendisk),
1155                                                       sh->dev[i].sector);
1156                         if (should_defer && op_is_write(op))
1157                                 bio_list_add(&pending_bios, bi);
1158                         else
1159                                 generic_make_request(bi);
1160                 }
1161                 if (rrdev) {
1162                         if (s->syncing || s->expanding || s->expanded
1163                             || s->replacing)
1164                                 md_sync_acct(rrdev->bdev, STRIPE_SECTORS);
1165
1166                         set_bit(STRIPE_IO_STARTED, &sh->state);
1167
1168                         bio_set_dev(rbi, rrdev->bdev);
1169                         bio_set_op_attrs(rbi, op, op_flags);
1170                         BUG_ON(!op_is_write(op));
1171                         rbi->bi_end_io = raid5_end_write_request;
1172                         rbi->bi_private = sh;
1173
1174                         pr_debug("%s: for %llu schedule op %d on "
1175                                  "replacement disc %d\n",
1176                                 __func__, (unsigned long long)sh->sector,
1177                                 rbi->bi_opf, i);
1178                         atomic_inc(&sh->count);
1179                         if (sh != head_sh)
1180                                 atomic_inc(&head_sh->count);
1181                         if (use_new_offset(conf, sh))
1182                                 rbi->bi_iter.bi_sector = (sh->sector
1183                                                   + rrdev->new_data_offset);
1184                         else
1185                                 rbi->bi_iter.bi_sector = (sh->sector
1186                                                   + rrdev->data_offset);
1187                         if (test_bit(R5_SkipCopy, &sh->dev[i].flags))
1188                                 WARN_ON(test_bit(R5_UPTODATE, &sh->dev[i].flags));
1189                         sh->dev[i].rvec.bv_page = sh->dev[i].page;
1190                         rbi->bi_vcnt = 1;
1191                         rbi->bi_io_vec[0].bv_len = STRIPE_SIZE;
1192                         rbi->bi_io_vec[0].bv_offset = 0;
1193                         rbi->bi_iter.bi_size = STRIPE_SIZE;
1194                         /*
1195                          * If this is discard request, set bi_vcnt 0. We don't
1196                          * want to confuse SCSI because SCSI will replace payload
1197                          */
1198                         if (op == REQ_OP_DISCARD)
1199                                 rbi->bi_vcnt = 0;
1200                         if (conf->mddev->gendisk)
1201                                 trace_block_bio_remap(rbi->bi_disk->queue,
1202                                                       rbi, disk_devt(conf->mddev->gendisk),
1203                                                       sh->dev[i].sector);
1204                         if (should_defer && op_is_write(op))
1205                                 bio_list_add(&pending_bios, rbi);
1206                         else
1207                                 generic_make_request(rbi);
1208                 }
1209                 if (!rdev && !rrdev) {
1210                         if (op_is_write(op))
1211                                 set_bit(STRIPE_DEGRADED, &sh->state);
1212                         pr_debug("skip op %d on disc %d for sector %llu\n",
1213                                 bi->bi_opf, i, (unsigned long long)sh->sector);
1214                         clear_bit(R5_LOCKED, &sh->dev[i].flags);
1215                         set_bit(STRIPE_HANDLE, &sh->state);
1216                 }
1217
1218                 if (!head_sh->batch_head)
1219                         continue;
1220                 sh = list_first_entry(&sh->batch_list, struct stripe_head,
1221                                       batch_list);
1222                 if (sh != head_sh)
1223                         goto again;
1224         }
1225
1226         if (should_defer && !bio_list_empty(&pending_bios))
1227                 defer_issue_bios(conf, head_sh->sector, &pending_bios);
1228 }
1229
1230 static struct dma_async_tx_descriptor *
1231 async_copy_data(int frombio, struct bio *bio, struct page **page,
1232         sector_t sector, struct dma_async_tx_descriptor *tx,
1233         struct stripe_head *sh, int no_skipcopy)
1234 {
1235         struct bio_vec bvl;
1236         struct bvec_iter iter;
1237         struct page *bio_page;
1238         int page_offset;
1239         struct async_submit_ctl submit;
1240         enum async_tx_flags flags = 0;
1241
1242         if (bio->bi_iter.bi_sector >= sector)
1243                 page_offset = (signed)(bio->bi_iter.bi_sector - sector) * 512;
1244         else
1245                 page_offset = (signed)(sector - bio->bi_iter.bi_sector) * -512;
1246
1247         if (frombio)
1248                 flags |= ASYNC_TX_FENCE;
1249         init_async_submit(&submit, flags, tx, NULL, NULL, NULL);
1250
1251         bio_for_each_segment(bvl, bio, iter) {
1252                 int len = bvl.bv_len;
1253                 int clen;
1254                 int b_offset = 0;
1255
1256                 if (page_offset < 0) {
1257                         b_offset = -page_offset;
1258                         page_offset += b_offset;
1259                         len -= b_offset;
1260                 }
1261
1262                 if (len > 0 && page_offset + len > STRIPE_SIZE)
1263                         clen = STRIPE_SIZE - page_offset;
1264                 else
1265                         clen = len;
1266
1267                 if (clen > 0) {
1268                         b_offset += bvl.bv_offset;
1269                         bio_page = bvl.bv_page;
1270                         if (frombio) {
1271                                 if (sh->raid_conf->skip_copy &&
1272                                     b_offset == 0 && page_offset == 0 &&
1273                                     clen == STRIPE_SIZE &&
1274                                     !no_skipcopy)
1275                                         *page = bio_page;
1276                                 else
1277                                         tx = async_memcpy(*page, bio_page, page_offset,
1278                                                   b_offset, clen, &submit);
1279                         } else
1280                                 tx = async_memcpy(bio_page, *page, b_offset,
1281                                                   page_offset, clen, &submit);
1282                 }
1283                 /* chain the operations */
1284                 submit.depend_tx = tx;
1285
1286                 if (clen < len) /* hit end of page */
1287                         break;
1288                 page_offset +=  len;
1289         }
1290
1291         return tx;
1292 }
1293
1294 static void ops_complete_biofill(void *stripe_head_ref)
1295 {
1296         struct stripe_head *sh = stripe_head_ref;
1297         int i;
1298
1299         pr_debug("%s: stripe %llu\n", __func__,
1300                 (unsigned long long)sh->sector);
1301
1302         /* clear completed biofills */
1303         for (i = sh->disks; i--; ) {
1304                 struct r5dev *dev = &sh->dev[i];
1305
1306                 /* acknowledge completion of a biofill operation */
1307                 /* and check if we need to reply to a read request,
1308                  * new R5_Wantfill requests are held off until
1309                  * !STRIPE_BIOFILL_RUN
1310                  */
1311                 if (test_and_clear_bit(R5_Wantfill, &dev->flags)) {
1312                         struct bio *rbi, *rbi2;
1313
1314                         BUG_ON(!dev->read);
1315                         rbi = dev->read;
1316                         dev->read = NULL;
1317                         while (rbi && rbi->bi_iter.bi_sector <
1318                                 dev->sector + STRIPE_SECTORS) {
1319                                 rbi2 = r5_next_bio(rbi, dev->sector);
1320                                 bio_endio(rbi);
1321                                 rbi = rbi2;
1322                         }
1323                 }
1324         }
1325         clear_bit(STRIPE_BIOFILL_RUN, &sh->state);
1326
1327         set_bit(STRIPE_HANDLE, &sh->state);
1328         raid5_release_stripe(sh);
1329 }
1330
1331 static void ops_run_biofill(struct stripe_head *sh)
1332 {
1333         struct dma_async_tx_descriptor *tx = NULL;
1334         struct async_submit_ctl submit;
1335         int i;
1336
1337         BUG_ON(sh->batch_head);
1338         pr_debug("%s: stripe %llu\n", __func__,
1339                 (unsigned long long)sh->sector);
1340
1341         for (i = sh->disks; i--; ) {
1342                 struct r5dev *dev = &sh->dev[i];
1343                 if (test_bit(R5_Wantfill, &dev->flags)) {
1344                         struct bio *rbi;
1345                         spin_lock_irq(&sh->stripe_lock);
1346                         dev->read = rbi = dev->toread;
1347                         dev->toread = NULL;
1348                         spin_unlock_irq(&sh->stripe_lock);
1349                         while (rbi && rbi->bi_iter.bi_sector <
1350                                 dev->sector + STRIPE_SECTORS) {
1351                                 tx = async_copy_data(0, rbi, &dev->page,
1352                                                      dev->sector, tx, sh, 0);
1353                                 rbi = r5_next_bio(rbi, dev->sector);
1354                         }
1355                 }
1356         }
1357
1358         atomic_inc(&sh->count);
1359         init_async_submit(&submit, ASYNC_TX_ACK, tx, ops_complete_biofill, sh, NULL);
1360         async_trigger_callback(&submit);
1361 }
1362
1363 static void mark_target_uptodate(struct stripe_head *sh, int target)
1364 {
1365         struct r5dev *tgt;
1366
1367         if (target < 0)
1368                 return;
1369
1370         tgt = &sh->dev[target];
1371         set_bit(R5_UPTODATE, &tgt->flags);
1372         BUG_ON(!test_bit(R5_Wantcompute, &tgt->flags));
1373         clear_bit(R5_Wantcompute, &tgt->flags);
1374 }
1375
1376 static void ops_complete_compute(void *stripe_head_ref)
1377 {
1378         struct stripe_head *sh = stripe_head_ref;
1379
1380         pr_debug("%s: stripe %llu\n", __func__,
1381                 (unsigned long long)sh->sector);
1382
1383         /* mark the computed target(s) as uptodate */
1384         mark_target_uptodate(sh, sh->ops.target);
1385         mark_target_uptodate(sh, sh->ops.target2);
1386
1387         clear_bit(STRIPE_COMPUTE_RUN, &sh->state);
1388         if (sh->check_state == check_state_compute_run)
1389                 sh->check_state = check_state_compute_result;
1390         set_bit(STRIPE_HANDLE, &sh->state);
1391         raid5_release_stripe(sh);
1392 }
1393
1394 /* return a pointer to the address conversion region of the scribble buffer */
1395 static addr_conv_t *to_addr_conv(struct stripe_head *sh,
1396                                  struct raid5_percpu *percpu, int i)
1397 {
1398         void *addr;
1399
1400         addr = flex_array_get(percpu->scribble, i);
1401         return addr + sizeof(struct page *) * (sh->disks + 2);
1402 }
1403
1404 /* return a pointer to the address conversion region of the scribble buffer */
1405 static struct page **to_addr_page(struct raid5_percpu *percpu, int i)
1406 {
1407         void *addr;
1408
1409         addr = flex_array_get(percpu->scribble, i);
1410         return addr;
1411 }
1412
1413 static struct dma_async_tx_descriptor *
1414 ops_run_compute5(struct stripe_head *sh, struct raid5_percpu *percpu)
1415 {
1416         int disks = sh->disks;
1417         struct page **xor_srcs = to_addr_page(percpu, 0);
1418         int target = sh->ops.target;
1419         struct r5dev *tgt = &sh->dev[target];
1420         struct page *xor_dest = tgt->page;
1421         int count = 0;
1422         struct dma_async_tx_descriptor *tx;
1423         struct async_submit_ctl submit;
1424         int i;
1425
1426         BUG_ON(sh->batch_head);
1427
1428         pr_debug("%s: stripe %llu block: %d\n",
1429                 __func__, (unsigned long long)sh->sector, target);
1430         BUG_ON(!test_bit(R5_Wantcompute, &tgt->flags));
1431
1432         for (i = disks; i--; )
1433                 if (i != target)
1434                         xor_srcs[count++] = sh->dev[i].page;
1435
1436         atomic_inc(&sh->count);
1437
1438         init_async_submit(&submit, ASYNC_TX_FENCE|ASYNC_TX_XOR_ZERO_DST, NULL,
1439                           ops_complete_compute, sh, to_addr_conv(sh, percpu, 0));
1440         if (unlikely(count == 1))
1441                 tx = async_memcpy(xor_dest, xor_srcs[0], 0, 0, STRIPE_SIZE, &submit);
1442         else
1443                 tx = async_xor(xor_dest, xor_srcs, 0, count, STRIPE_SIZE, &submit);
1444
1445         return tx;
1446 }
1447
1448 /* set_syndrome_sources - populate source buffers for gen_syndrome
1449  * @srcs - (struct page *) array of size sh->disks
1450  * @sh - stripe_head to parse
1451  *
1452  * Populates srcs in proper layout order for the stripe and returns the
1453  * 'count' of sources to be used in a call to async_gen_syndrome.  The P
1454  * destination buffer is recorded in srcs[count] and the Q destination
1455  * is recorded in srcs[count+1]].
1456  */
1457 static int set_syndrome_sources(struct page **srcs,
1458                                 struct stripe_head *sh,
1459                                 int srctype)
1460 {
1461         int disks = sh->disks;
1462         int syndrome_disks = sh->ddf_layout ? disks : (disks - 2);
1463         int d0_idx = raid6_d0(sh);
1464         int count;
1465         int i;
1466
1467         for (i = 0; i < disks; i++)
1468                 srcs[i] = NULL;
1469
1470         count = 0;
1471         i = d0_idx;
1472         do {
1473                 int slot = raid6_idx_to_slot(i, sh, &count, syndrome_disks);
1474                 struct r5dev *dev = &sh->dev[i];
1475
1476                 if (i == sh->qd_idx || i == sh->pd_idx ||
1477                     (srctype == SYNDROME_SRC_ALL) ||
1478                     (srctype == SYNDROME_SRC_WANT_DRAIN &&
1479                      (test_bit(R5_Wantdrain, &dev->flags) ||
1480                       test_bit(R5_InJournal, &dev->flags))) ||
1481                     (srctype == SYNDROME_SRC_WRITTEN &&
1482                      (dev->written ||
1483                       test_bit(R5_InJournal, &dev->flags)))) {
1484                         if (test_bit(R5_InJournal, &dev->flags))
1485                                 srcs[slot] = sh->dev[i].orig_page;
1486                         else
1487                                 srcs[slot] = sh->dev[i].page;
1488                 }
1489                 i = raid6_next_disk(i, disks);
1490         } while (i != d0_idx);
1491
1492         return syndrome_disks;
1493 }
1494
1495 static struct dma_async_tx_descriptor *
1496 ops_run_compute6_1(struct stripe_head *sh, struct raid5_percpu *percpu)
1497 {
1498         int disks = sh->disks;
1499         struct page **blocks = to_addr_page(percpu, 0);
1500         int target;
1501         int qd_idx = sh->qd_idx;
1502         struct dma_async_tx_descriptor *tx;
1503         struct async_submit_ctl submit;
1504         struct r5dev *tgt;
1505         struct page *dest;
1506         int i;
1507         int count;
1508
1509         BUG_ON(sh->batch_head);
1510         if (sh->ops.target < 0)
1511                 target = sh->ops.target2;
1512         else if (sh->ops.target2 < 0)
1513                 target = sh->ops.target;
1514         else
1515                 /* we should only have one valid target */
1516                 BUG();
1517         BUG_ON(target < 0);
1518         pr_debug("%s: stripe %llu block: %d\n",
1519                 __func__, (unsigned long long)sh->sector, target);
1520
1521         tgt = &sh->dev[target];
1522         BUG_ON(!test_bit(R5_Wantcompute, &tgt->flags));
1523         dest = tgt->page;
1524
1525         atomic_inc(&sh->count);
1526
1527         if (target == qd_idx) {
1528                 count = set_syndrome_sources(blocks, sh, SYNDROME_SRC_ALL);
1529                 blocks[count] = NULL; /* regenerating p is not necessary */
1530                 BUG_ON(blocks[count+1] != dest); /* q should already be set */
1531                 init_async_submit(&submit, ASYNC_TX_FENCE, NULL,
1532                                   ops_complete_compute, sh,
1533                                   to_addr_conv(sh, percpu, 0));
1534                 tx = async_gen_syndrome(blocks, 0, count+2, STRIPE_SIZE, &submit);
1535         } else {
1536                 /* Compute any data- or p-drive using XOR */
1537                 count = 0;
1538                 for (i = disks; i-- ; ) {
1539                         if (i == target || i == qd_idx)
1540                                 continue;
1541                         blocks[count++] = sh->dev[i].page;
1542                 }
1543
1544                 init_async_submit(&submit, ASYNC_TX_FENCE|ASYNC_TX_XOR_ZERO_DST,
1545                                   NULL, ops_complete_compute, sh,
1546                                   to_addr_conv(sh, percpu, 0));
1547                 tx = async_xor(dest, blocks, 0, count, STRIPE_SIZE, &submit);
1548         }
1549
1550         return tx;
1551 }
1552
1553 static struct dma_async_tx_descriptor *
1554 ops_run_compute6_2(struct stripe_head *sh, struct raid5_percpu *percpu)
1555 {
1556         int i, count, disks = sh->disks;
1557         int syndrome_disks = sh->ddf_layout ? disks : disks-2;
1558         int d0_idx = raid6_d0(sh);
1559         int faila = -1, failb = -1;
1560         int target = sh->ops.target;
1561         int target2 = sh->ops.target2;
1562         struct r5dev *tgt = &sh->dev[target];
1563         struct r5dev *tgt2 = &sh->dev[target2];
1564         struct dma_async_tx_descriptor *tx;
1565         struct page **blocks = to_addr_page(percpu, 0);
1566         struct async_submit_ctl submit;
1567
1568         BUG_ON(sh->batch_head);
1569         pr_debug("%s: stripe %llu block1: %d block2: %d\n",
1570                  __func__, (unsigned long long)sh->sector, target, target2);
1571         BUG_ON(target < 0 || target2 < 0);
1572         BUG_ON(!test_bit(R5_Wantcompute, &tgt->flags));
1573         BUG_ON(!test_bit(R5_Wantcompute, &tgt2->flags));
1574
1575         /* we need to open-code set_syndrome_sources to handle the
1576          * slot number conversion for 'faila' and 'failb'
1577          */
1578         for (i = 0; i < disks ; i++)
1579                 blocks[i] = NULL;
1580         count = 0;
1581         i = d0_idx;
1582         do {
1583                 int slot = raid6_idx_to_slot(i, sh, &count, syndrome_disks);
1584
1585                 blocks[slot] = sh->dev[i].page;
1586
1587                 if (i == target)
1588                         faila = slot;
1589                 if (i == target2)
1590                         failb = slot;
1591                 i = raid6_next_disk(i, disks);
1592         } while (i != d0_idx);
1593
1594         BUG_ON(faila == failb);
1595         if (failb < faila)
1596                 swap(faila, failb);
1597         pr_debug("%s: stripe: %llu faila: %d failb: %d\n",
1598                  __func__, (unsigned long long)sh->sector, faila, failb);
1599
1600         atomic_inc(&sh->count);
1601
1602         if (failb == syndrome_disks+1) {
1603                 /* Q disk is one of the missing disks */
1604                 if (faila == syndrome_disks) {
1605                         /* Missing P+Q, just recompute */
1606                         init_async_submit(&submit, ASYNC_TX_FENCE, NULL,
1607                                           ops_complete_compute, sh,
1608                                           to_addr_conv(sh, percpu, 0));
1609                         return async_gen_syndrome(blocks, 0, syndrome_disks+2,
1610                                                   STRIPE_SIZE, &submit);
1611                 } else {
1612                         struct page *dest;
1613                         int data_target;
1614                         int qd_idx = sh->qd_idx;
1615
1616                         /* Missing D+Q: recompute D from P, then recompute Q */
1617                         if (target == qd_idx)
1618                                 data_target = target2;
1619                         else
1620                                 data_target = target;
1621
1622                         count = 0;
1623                         for (i = disks; i-- ; ) {
1624                                 if (i == data_target || i == qd_idx)
1625                                         continue;
1626                                 blocks[count++] = sh->dev[i].page;
1627                         }
1628                         dest = sh->dev[data_target].page;
1629                         init_async_submit(&submit,
1630                                           ASYNC_TX_FENCE|ASYNC_TX_XOR_ZERO_DST,
1631                                           NULL, NULL, NULL,
1632                                           to_addr_conv(sh, percpu, 0));
1633                         tx = async_xor(dest, blocks, 0, count, STRIPE_SIZE,
1634                                        &submit);
1635
1636                         count = set_syndrome_sources(blocks, sh, SYNDROME_SRC_ALL);
1637                         init_async_submit(&submit, ASYNC_TX_FENCE, tx,
1638                                           ops_complete_compute, sh,
1639                                           to_addr_conv(sh, percpu, 0));
1640                         return async_gen_syndrome(blocks, 0, count+2,
1641                                                   STRIPE_SIZE, &submit);
1642                 }
1643         } else {
1644                 init_async_submit(&submit, ASYNC_TX_FENCE, NULL,
1645                                   ops_complete_compute, sh,
1646                                   to_addr_conv(sh, percpu, 0));
1647                 if (failb == syndrome_disks) {
1648                         /* We're missing D+P. */
1649                         return async_raid6_datap_recov(syndrome_disks+2,
1650                                                        STRIPE_SIZE, faila,
1651                                                        blocks, &submit);
1652                 } else {
1653                         /* We're missing D+D. */
1654                         return async_raid6_2data_recov(syndrome_disks+2,
1655                                                        STRIPE_SIZE, faila, failb,
1656                                                        blocks, &submit);
1657                 }
1658         }
1659 }
1660
1661 static void ops_complete_prexor(void *stripe_head_ref)
1662 {
1663         struct stripe_head *sh = stripe_head_ref;
1664
1665         pr_debug("%s: stripe %llu\n", __func__,
1666                 (unsigned long long)sh->sector);
1667
1668         if (r5c_is_writeback(sh->raid_conf->log))
1669                 /*
1670                  * raid5-cache write back uses orig_page during prexor.
1671                  * After prexor, it is time to free orig_page
1672                  */
1673                 r5c_release_extra_page(sh);
1674 }
1675
1676 static struct dma_async_tx_descriptor *
1677 ops_run_prexor5(struct stripe_head *sh, struct raid5_percpu *percpu,
1678                 struct dma_async_tx_descriptor *tx)
1679 {
1680         int disks = sh->disks;
1681         struct page **xor_srcs = to_addr_page(percpu, 0);
1682         int count = 0, pd_idx = sh->pd_idx, i;
1683         struct async_submit_ctl submit;
1684
1685         /* existing parity data subtracted */
1686         struct page *xor_dest = xor_srcs[count++] = sh->dev[pd_idx].page;
1687
1688         BUG_ON(sh->batch_head);
1689         pr_debug("%s: stripe %llu\n", __func__,
1690                 (unsigned long long)sh->sector);
1691
1692         for (i = disks; i--; ) {
1693                 struct r5dev *dev = &sh->dev[i];
1694                 /* Only process blocks that are known to be uptodate */
1695                 if (test_bit(R5_InJournal, &dev->flags))
1696                         xor_srcs[count++] = dev->orig_page;
1697                 else if (test_bit(R5_Wantdrain, &dev->flags))
1698                         xor_srcs[count++] = dev->page;
1699         }
1700
1701         init_async_submit(&submit, ASYNC_TX_FENCE|ASYNC_TX_XOR_DROP_DST, tx,
1702                           ops_complete_prexor, sh, to_addr_conv(sh, percpu, 0));
1703         tx = async_xor(xor_dest, xor_srcs, 0, count, STRIPE_SIZE, &submit);
1704
1705         return tx;
1706 }
1707
1708 static struct dma_async_tx_descriptor *
1709 ops_run_prexor6(struct stripe_head *sh, struct raid5_percpu *percpu,
1710                 struct dma_async_tx_descriptor *tx)
1711 {
1712         struct page **blocks = to_addr_page(percpu, 0);
1713         int count;
1714         struct async_submit_ctl submit;
1715
1716         pr_debug("%s: stripe %llu\n", __func__,
1717                 (unsigned long long)sh->sector);
1718
1719         count = set_syndrome_sources(blocks, sh, SYNDROME_SRC_WANT_DRAIN);
1720
1721         init_async_submit(&submit, ASYNC_TX_FENCE|ASYNC_TX_PQ_XOR_DST, tx,
1722                           ops_complete_prexor, sh, to_addr_conv(sh, percpu, 0));
1723         tx = async_gen_syndrome(blocks, 0, count+2, STRIPE_SIZE,  &submit);
1724
1725         return tx;
1726 }
1727
1728 static struct dma_async_tx_descriptor *
1729 ops_run_biodrain(struct stripe_head *sh, struct dma_async_tx_descriptor *tx)
1730 {
1731         struct r5conf *conf = sh->raid_conf;
1732         int disks = sh->disks;
1733         int i;
1734         struct stripe_head *head_sh = sh;
1735
1736         pr_debug("%s: stripe %llu\n", __func__,
1737                 (unsigned long long)sh->sector);
1738
1739         for (i = disks; i--; ) {
1740                 struct r5dev *dev;
1741                 struct bio *chosen;
1742
1743                 sh = head_sh;
1744                 if (test_and_clear_bit(R5_Wantdrain, &head_sh->dev[i].flags)) {
1745                         struct bio *wbi;
1746
1747 again:
1748                         dev = &sh->dev[i];
1749                         /*
1750                          * clear R5_InJournal, so when rewriting a page in
1751                          * journal, it is not skipped by r5l_log_stripe()
1752                          */
1753                         clear_bit(R5_InJournal, &dev->flags);
1754                         spin_lock_irq(&sh->stripe_lock);
1755                         chosen = dev->towrite;
1756                         dev->towrite = NULL;
1757                         sh->overwrite_disks = 0;
1758                         BUG_ON(dev->written);
1759                         wbi = dev->written = chosen;
1760                         spin_unlock_irq(&sh->stripe_lock);
1761                         WARN_ON(dev->page != dev->orig_page);
1762
1763                         while (wbi && wbi->bi_iter.bi_sector <
1764                                 dev->sector + STRIPE_SECTORS) {
1765                                 if (wbi->bi_opf & REQ_FUA)
1766                                         set_bit(R5_WantFUA, &dev->flags);
1767                                 if (wbi->bi_opf & REQ_SYNC)
1768                                         set_bit(R5_SyncIO, &dev->flags);
1769                                 if (bio_op(wbi) == REQ_OP_DISCARD)
1770                                         set_bit(R5_Discard, &dev->flags);
1771                                 else {
1772                                         tx = async_copy_data(1, wbi, &dev->page,
1773                                                              dev->sector, tx, sh,
1774                                                              r5c_is_writeback(conf->log));
1775                                         if (dev->page != dev->orig_page &&
1776                                             !r5c_is_writeback(conf->log)) {
1777                                                 set_bit(R5_SkipCopy, &dev->flags);
1778                                                 clear_bit(R5_UPTODATE, &dev->flags);
1779                                                 clear_bit(R5_OVERWRITE, &dev->flags);
1780                                         }
1781                                 }
1782                                 wbi = r5_next_bio(wbi, dev->sector);
1783                         }
1784
1785                         if (head_sh->batch_head) {
1786                                 sh = list_first_entry(&sh->batch_list,
1787                                                       struct stripe_head,
1788                                                       batch_list);
1789                                 if (sh == head_sh)
1790                                         continue;
1791                                 goto again;
1792                         }
1793                 }
1794         }
1795
1796         return tx;
1797 }
1798
1799 static void ops_complete_reconstruct(void *stripe_head_ref)
1800 {
1801         struct stripe_head *sh = stripe_head_ref;
1802         int disks = sh->disks;
1803         int pd_idx = sh->pd_idx;
1804         int qd_idx = sh->qd_idx;
1805         int i;
1806         bool fua = false, sync = false, discard = false;
1807
1808         pr_debug("%s: stripe %llu\n", __func__,
1809                 (unsigned long long)sh->sector);
1810
1811         for (i = disks; i--; ) {
1812                 fua |= test_bit(R5_WantFUA, &sh->dev[i].flags);
1813                 sync |= test_bit(R5_SyncIO, &sh->dev[i].flags);
1814                 discard |= test_bit(R5_Discard, &sh->dev[i].flags);
1815         }
1816
1817         for (i = disks; i--; ) {
1818                 struct r5dev *dev = &sh->dev[i];
1819
1820                 if (dev->written || i == pd_idx || i == qd_idx) {
1821                         if (!discard && !test_bit(R5_SkipCopy, &dev->flags))
1822                                 set_bit(R5_UPTODATE, &dev->flags);
1823                         if (fua)
1824                                 set_bit(R5_WantFUA, &dev->flags);
1825                         if (sync)
1826                                 set_bit(R5_SyncIO, &dev->flags);
1827                 }
1828         }
1829
1830         if (sh->reconstruct_state == reconstruct_state_drain_run)
1831                 sh->reconstruct_state = reconstruct_state_drain_result;
1832         else if (sh->reconstruct_state == reconstruct_state_prexor_drain_run)
1833                 sh->reconstruct_state = reconstruct_state_prexor_drain_result;
1834         else {
1835                 BUG_ON(sh->reconstruct_state != reconstruct_state_run);
1836                 sh->reconstruct_state = reconstruct_state_result;
1837         }
1838
1839         set_bit(STRIPE_HANDLE, &sh->state);
1840         raid5_release_stripe(sh);
1841 }
1842
1843 static void
1844 ops_run_reconstruct5(struct stripe_head *sh, struct raid5_percpu *percpu,
1845                      struct dma_async_tx_descriptor *tx)
1846 {
1847         int disks = sh->disks;
1848         struct page **xor_srcs;
1849         struct async_submit_ctl submit;
1850         int count, pd_idx = sh->pd_idx, i;
1851         struct page *xor_dest;
1852         int prexor = 0;
1853         unsigned long flags;
1854         int j = 0;
1855         struct stripe_head *head_sh = sh;
1856         int last_stripe;
1857
1858         pr_debug("%s: stripe %llu\n", __func__,
1859                 (unsigned long long)sh->sector);
1860
1861         for (i = 0; i < sh->disks; i++) {
1862                 if (pd_idx == i)
1863                         continue;
1864                 if (!test_bit(R5_Discard, &sh->dev[i].flags))
1865                         break;
1866         }
1867         if (i >= sh->disks) {
1868                 atomic_inc(&sh->count);
1869                 set_bit(R5_Discard, &sh->dev[pd_idx].flags);
1870                 ops_complete_reconstruct(sh);
1871                 return;
1872         }
1873 again:
1874         count = 0;
1875         xor_srcs = to_addr_page(percpu, j);
1876         /* check if prexor is active which means only process blocks
1877          * that are part of a read-modify-write (written)
1878          */
1879         if (head_sh->reconstruct_state == reconstruct_state_prexor_drain_run) {
1880                 prexor = 1;
1881                 xor_dest = xor_srcs[count++] = sh->dev[pd_idx].page;
1882                 for (i = disks; i--; ) {
1883                         struct r5dev *dev = &sh->dev[i];
1884                         if (head_sh->dev[i].written ||
1885                             test_bit(R5_InJournal, &head_sh->dev[i].flags))
1886                                 xor_srcs[count++] = dev->page;
1887                 }
1888         } else {
1889                 xor_dest = sh->dev[pd_idx].page;
1890                 for (i = disks; i--; ) {
1891                         struct r5dev *dev = &sh->dev[i];
1892                         if (i != pd_idx)
1893                                 xor_srcs[count++] = dev->page;
1894                 }
1895         }
1896
1897         /* 1/ if we prexor'd then the dest is reused as a source
1898          * 2/ if we did not prexor then we are redoing the parity
1899          * set ASYNC_TX_XOR_DROP_DST and ASYNC_TX_XOR_ZERO_DST
1900          * for the synchronous xor case
1901          */
1902         last_stripe = !head_sh->batch_head ||
1903                 list_first_entry(&sh->batch_list,
1904                                  struct stripe_head, batch_list) == head_sh;
1905         if (last_stripe) {
1906                 flags = ASYNC_TX_ACK |
1907                         (prexor ? ASYNC_TX_XOR_DROP_DST : ASYNC_TX_XOR_ZERO_DST);
1908
1909                 atomic_inc(&head_sh->count);
1910                 init_async_submit(&submit, flags, tx, ops_complete_reconstruct, head_sh,
1911                                   to_addr_conv(sh, percpu, j));
1912         } else {
1913                 flags = prexor ? ASYNC_TX_XOR_DROP_DST : ASYNC_TX_XOR_ZERO_DST;
1914                 init_async_submit(&submit, flags, tx, NULL, NULL,
1915                                   to_addr_conv(sh, percpu, j));
1916         }
1917
1918         if (unlikely(count == 1))
1919                 tx = async_memcpy(xor_dest, xor_srcs[0], 0, 0, STRIPE_SIZE, &submit);
1920         else
1921                 tx = async_xor(xor_dest, xor_srcs, 0, count, STRIPE_SIZE, &submit);
1922         if (!last_stripe) {
1923                 j++;
1924                 sh = list_first_entry(&sh->batch_list, struct stripe_head,
1925                                       batch_list);
1926                 goto again;
1927         }
1928 }
1929
1930 static void
1931 ops_run_reconstruct6(struct stripe_head *sh, struct raid5_percpu *percpu,
1932                      struct dma_async_tx_descriptor *tx)
1933 {
1934         struct async_submit_ctl submit;
1935         struct page **blocks;
1936         int count, i, j = 0;
1937         struct stripe_head *head_sh = sh;
1938         int last_stripe;
1939         int synflags;
1940         unsigned long txflags;
1941
1942         pr_debug("%s: stripe %llu\n", __func__, (unsigned long long)sh->sector);
1943
1944         for (i = 0; i < sh->disks; i++) {
1945                 if (sh->pd_idx == i || sh->qd_idx == i)
1946                         continue;
1947                 if (!test_bit(R5_Discard, &sh->dev[i].flags))
1948                         break;
1949         }
1950         if (i >= sh->disks) {
1951                 atomic_inc(&sh->count);
1952                 set_bit(R5_Discard, &sh->dev[sh->pd_idx].flags);
1953                 set_bit(R5_Discard, &sh->dev[sh->qd_idx].flags);
1954                 ops_complete_reconstruct(sh);
1955                 return;
1956         }
1957
1958 again:
1959         blocks = to_addr_page(percpu, j);
1960
1961         if (sh->reconstruct_state == reconstruct_state_prexor_drain_run) {
1962                 synflags = SYNDROME_SRC_WRITTEN;
1963                 txflags = ASYNC_TX_ACK | ASYNC_TX_PQ_XOR_DST;
1964         } else {
1965                 synflags = SYNDROME_SRC_ALL;
1966                 txflags = ASYNC_TX_ACK;
1967         }
1968
1969         count = set_syndrome_sources(blocks, sh, synflags);
1970         last_stripe = !head_sh->batch_head ||
1971                 list_first_entry(&sh->batch_list,
1972                                  struct stripe_head, batch_list) == head_sh;
1973
1974         if (last_stripe) {
1975                 atomic_inc(&head_sh->count);
1976                 init_async_submit(&submit, txflags, tx, ops_complete_reconstruct,
1977                                   head_sh, to_addr_conv(sh, percpu, j));
1978         } else
1979                 init_async_submit(&submit, 0, tx, NULL, NULL,
1980                                   to_addr_conv(sh, percpu, j));
1981         tx = async_gen_syndrome(blocks, 0, count+2, STRIPE_SIZE,  &submit);
1982         if (!last_stripe) {
1983                 j++;
1984                 sh = list_first_entry(&sh->batch_list, struct stripe_head,
1985                                       batch_list);
1986                 goto again;
1987         }
1988 }
1989
1990 static void ops_complete_check(void *stripe_head_ref)
1991 {
1992         struct stripe_head *sh = stripe_head_ref;
1993
1994         pr_debug("%s: stripe %llu\n", __func__,
1995                 (unsigned long long)sh->sector);
1996
1997         sh->check_state = check_state_check_result;
1998         set_bit(STRIPE_HANDLE, &sh->state);
1999         raid5_release_stripe(sh);
2000 }
2001
2002 static void ops_run_check_p(struct stripe_head *sh, struct raid5_percpu *percpu)
2003 {
2004         int disks = sh->disks;
2005         int pd_idx = sh->pd_idx;
2006         int qd_idx = sh->qd_idx;
2007         struct page *xor_dest;
2008         struct page **xor_srcs = to_addr_page(percpu, 0);
2009         struct dma_async_tx_descriptor *tx;
2010         struct async_submit_ctl submit;
2011         int count;
2012         int i;
2013
2014         pr_debug("%s: stripe %llu\n", __func__,
2015                 (unsigned long long)sh->sector);
2016
2017         BUG_ON(sh->batch_head);
2018         count = 0;
2019         xor_dest = sh->dev[pd_idx].page;
2020         xor_srcs[count++] = xor_dest;
2021         for (i = disks; i--; ) {
2022                 if (i == pd_idx || i == qd_idx)
2023                         continue;
2024                 xor_srcs[count++] = sh->dev[i].page;
2025         }
2026
2027         init_async_submit(&submit, 0, NULL, NULL, NULL,
2028                           to_addr_conv(sh, percpu, 0));
2029         tx = async_xor_val(xor_dest, xor_srcs, 0, count, STRIPE_SIZE,
2030                            &sh->ops.zero_sum_result, &submit);
2031
2032         atomic_inc(&sh->count);
2033         init_async_submit(&submit, ASYNC_TX_ACK, tx, ops_complete_check, sh, NULL);
2034         tx = async_trigger_callback(&submit);
2035 }
2036
2037 static void ops_run_check_pq(struct stripe_head *sh, struct raid5_percpu *percpu, int checkp)
2038 {
2039         struct page **srcs = to_addr_page(percpu, 0);
2040         struct async_submit_ctl submit;
2041         int count;
2042
2043         pr_debug("%s: stripe %llu checkp: %d\n", __func__,
2044                 (unsigned long long)sh->sector, checkp);
2045
2046         BUG_ON(sh->batch_head);
2047         count = set_syndrome_sources(srcs, sh, SYNDROME_SRC_ALL);
2048         if (!checkp)
2049                 srcs[count] = NULL;
2050
2051         atomic_inc(&sh->count);
2052         init_async_submit(&submit, ASYNC_TX_ACK, NULL, ops_complete_check,
2053                           sh, to_addr_conv(sh, percpu, 0));
2054         async_syndrome_val(srcs, 0, count+2, STRIPE_SIZE,
2055                            &sh->ops.zero_sum_result, percpu->spare_page, &submit);
2056 }
2057
2058 static void raid_run_ops(struct stripe_head *sh, unsigned long ops_request)
2059 {
2060         int overlap_clear = 0, i, disks = sh->disks;
2061         struct dma_async_tx_descriptor *tx = NULL;
2062         struct r5conf *conf = sh->raid_conf;
2063         int level = conf->level;
2064         struct raid5_percpu *percpu;
2065         unsigned long cpu;
2066
2067         cpu = get_cpu();
2068         percpu = per_cpu_ptr(conf->percpu, cpu);
2069         if (test_bit(STRIPE_OP_BIOFILL, &ops_request)) {
2070                 ops_run_biofill(sh);
2071                 overlap_clear++;
2072         }
2073
2074         if (test_bit(STRIPE_OP_COMPUTE_BLK, &ops_request)) {
2075                 if (level < 6)
2076                         tx = ops_run_compute5(sh, percpu);
2077                 else {
2078                         if (sh->ops.target2 < 0 || sh->ops.target < 0)
2079                                 tx = ops_run_compute6_1(sh, percpu);
2080                         else
2081                                 tx = ops_run_compute6_2(sh, percpu);
2082                 }
2083                 /* terminate the chain if reconstruct is not set to be run */
2084                 if (tx && !test_bit(STRIPE_OP_RECONSTRUCT, &ops_request))
2085                         async_tx_ack(tx);
2086         }
2087
2088         if (test_bit(STRIPE_OP_PREXOR, &ops_request)) {
2089                 if (level < 6)
2090                         tx = ops_run_prexor5(sh, percpu, tx);
2091                 else
2092                         tx = ops_run_prexor6(sh, percpu, tx);
2093         }
2094
2095         if (test_bit(STRIPE_OP_PARTIAL_PARITY, &ops_request))
2096                 tx = ops_run_partial_parity(sh, percpu, tx);
2097
2098         if (test_bit(STRIPE_OP_BIODRAIN, &ops_request)) {
2099                 tx = ops_run_biodrain(sh, tx);
2100                 overlap_clear++;
2101         }
2102
2103         if (test_bit(STRIPE_OP_RECONSTRUCT, &ops_request)) {
2104                 if (level < 6)
2105                         ops_run_reconstruct5(sh, percpu, tx);
2106                 else
2107                         ops_run_reconstruct6(sh, percpu, tx);
2108         }
2109
2110         if (test_bit(STRIPE_OP_CHECK, &ops_request)) {
2111                 if (sh->check_state == check_state_run)
2112                         ops_run_check_p(sh, percpu);
2113                 else if (sh->check_state == check_state_run_q)
2114                         ops_run_check_pq(sh, percpu, 0);
2115                 else if (sh->check_state == check_state_run_pq)
2116                         ops_run_check_pq(sh, percpu, 1);
2117                 else
2118                         BUG();
2119         }
2120
2121         if (overlap_clear && !sh->batch_head)
2122                 for (i = disks; i--; ) {
2123                         struct r5dev *dev = &sh->dev[i];
2124                         if (test_and_clear_bit(R5_Overlap, &dev->flags))
2125                                 wake_up(&sh->raid_conf->wait_for_overlap);
2126                 }
2127         put_cpu();
2128 }
2129
2130 static void free_stripe(struct kmem_cache *sc, struct stripe_head *sh)
2131 {
2132         if (sh->ppl_page)
2133                 __free_page(sh->ppl_page);
2134         kmem_cache_free(sc, sh);
2135 }
2136
2137 static struct stripe_head *alloc_stripe(struct kmem_cache *sc, gfp_t gfp,
2138         int disks, struct r5conf *conf)
2139 {
2140         struct stripe_head *sh;
2141         int i;
2142
2143         sh = kmem_cache_zalloc(sc, gfp);
2144         if (sh) {
2145                 spin_lock_init(&sh->stripe_lock);
2146                 spin_lock_init(&sh->batch_lock);
2147                 INIT_LIST_HEAD(&sh->batch_list);
2148                 INIT_LIST_HEAD(&sh->lru);
2149                 INIT_LIST_HEAD(&sh->r5c);
2150                 INIT_LIST_HEAD(&sh->log_list);
2151                 atomic_set(&sh->count, 1);
2152                 sh->raid_conf = conf;
2153                 sh->log_start = MaxSector;
2154                 for (i = 0; i < disks; i++) {
2155                         struct r5dev *dev = &sh->dev[i];
2156
2157                         bio_init(&dev->req, &dev->vec, 1);
2158                         bio_init(&dev->rreq, &dev->rvec, 1);
2159                 }
2160
2161                 if (raid5_has_ppl(conf)) {
2162                         sh->ppl_page = alloc_page(gfp);
2163                         if (!sh->ppl_page) {
2164                                 free_stripe(sc, sh);
2165                                 sh = NULL;
2166                         }
2167                 }
2168         }
2169         return sh;
2170 }
2171 static int grow_one_stripe(struct r5conf *conf, gfp_t gfp)
2172 {
2173         struct stripe_head *sh;
2174
2175         sh = alloc_stripe(conf->slab_cache, gfp, conf->pool_size, conf);
2176         if (!sh)
2177                 return 0;
2178
2179         if (grow_buffers(sh, gfp)) {
2180                 shrink_buffers(sh);
2181                 free_stripe(conf->slab_cache, sh);
2182                 return 0;
2183         }
2184         sh->hash_lock_index =
2185                 conf->max_nr_stripes % NR_STRIPE_HASH_LOCKS;
2186         /* we just created an active stripe so... */
2187         atomic_inc(&conf->active_stripes);
2188
2189         raid5_release_stripe(sh);
2190         conf->max_nr_stripes++;
2191         return 1;
2192 }
2193
2194 static int grow_stripes(struct r5conf *conf, int num)
2195 {
2196         struct kmem_cache *sc;
2197         int devs = max(conf->raid_disks, conf->previous_raid_disks);
2198
2199         if (conf->mddev->gendisk)
2200                 sprintf(conf->cache_name[0],
2201                         "raid%d-%s", conf->level, mdname(conf->mddev));
2202         else
2203                 sprintf(conf->cache_name[0],
2204                         "raid%d-%p", conf->level, conf->mddev);
2205         sprintf(conf->cache_name[1], "%s-alt", conf->cache_name[0]);
2206
2207         conf->active_name = 0;
2208         sc = kmem_cache_create(conf->cache_name[conf->active_name],
2209                                sizeof(struct stripe_head)+(devs-1)*sizeof(struct r5dev),
2210                                0, 0, NULL);
2211         if (!sc)
2212                 return 1;
2213         conf->slab_cache = sc;
2214         conf->pool_size = devs;
2215         while (num--)
2216                 if (!grow_one_stripe(conf, GFP_KERNEL))
2217                         return 1;
2218
2219         return 0;
2220 }
2221
2222 /**
2223  * scribble_len - return the required size of the scribble region
2224  * @num - total number of disks in the array
2225  *
2226  * The size must be enough to contain:
2227  * 1/ a struct page pointer for each device in the array +2
2228  * 2/ room to convert each entry in (1) to its corresponding dma
2229  *    (dma_map_page()) or page (page_address()) address.
2230  *
2231  * Note: the +2 is for the destination buffers of the ddf/raid6 case where we
2232  * calculate over all devices (not just the data blocks), using zeros in place
2233  * of the P and Q blocks.
2234  */
2235 static struct flex_array *scribble_alloc(int num, int cnt, gfp_t flags)
2236 {
2237         struct flex_array *ret;
2238         size_t len;
2239
2240         len = sizeof(struct page *) * (num+2) + sizeof(addr_conv_t) * (num+2);
2241         ret = flex_array_alloc(len, cnt, flags);
2242         if (!ret)
2243                 return NULL;
2244         /* always prealloc all elements, so no locking is required */
2245         if (flex_array_prealloc(ret, 0, cnt, flags)) {
2246                 flex_array_free(ret);
2247                 return NULL;
2248         }
2249         return ret;
2250 }
2251
2252 static int resize_chunks(struct r5conf *conf, int new_disks, int new_sectors)
2253 {
2254         unsigned long cpu;
2255         int err = 0;
2256
2257         /*
2258          * Never shrink. And mddev_suspend() could deadlock if this is called
2259          * from raid5d. In that case, scribble_disks and scribble_sectors
2260          * should equal to new_disks and new_sectors
2261          */
2262         if (conf->scribble_disks >= new_disks &&
2263             conf->scribble_sectors >= new_sectors)
2264                 return 0;
2265         mddev_suspend(conf->mddev);
2266         get_online_cpus();
2267         for_each_present_cpu(cpu) {
2268                 struct raid5_percpu *percpu;
2269                 struct flex_array *scribble;
2270
2271                 percpu = per_cpu_ptr(conf->percpu, cpu);
2272                 scribble = scribble_alloc(new_disks,
2273                                           new_sectors / STRIPE_SECTORS,
2274                                           GFP_NOIO);
2275
2276                 if (scribble) {
2277                         flex_array_free(percpu->scribble);
2278                         percpu->scribble = scribble;
2279                 } else {
2280                         err = -ENOMEM;
2281                         break;
2282                 }
2283         }
2284         put_online_cpus();
2285         mddev_resume(conf->mddev);
2286         if (!err) {
2287                 conf->scribble_disks = new_disks;
2288                 conf->scribble_sectors = new_sectors;
2289         }
2290         return err;
2291 }
2292
2293 static int resize_stripes(struct r5conf *conf, int newsize)
2294 {
2295         /* Make all the stripes able to hold 'newsize' devices.
2296          * New slots in each stripe get 'page' set to a new page.
2297          *
2298          * This happens in stages:
2299          * 1/ create a new kmem_cache and allocate the required number of
2300          *    stripe_heads.
2301          * 2/ gather all the old stripe_heads and transfer the pages across
2302          *    to the new stripe_heads.  This will have the side effect of
2303          *    freezing the array as once all stripe_heads have been collected,
2304          *    no IO will be possible.  Old stripe heads are freed once their
2305          *    pages have been transferred over, and the old kmem_cache is
2306          *    freed when all stripes are done.
2307          * 3/ reallocate conf->disks to be suitable bigger.  If this fails,
2308          *    we simple return a failure status - no need to clean anything up.
2309          * 4/ allocate new pages for the new slots in the new stripe_heads.
2310          *    If this fails, we don't bother trying the shrink the
2311          *    stripe_heads down again, we just leave them as they are.
2312          *    As each stripe_head is processed the new one is released into
2313          *    active service.
2314          *
2315          * Once step2 is started, we cannot afford to wait for a write,
2316          * so we use GFP_NOIO allocations.
2317          */
2318         struct stripe_head *osh, *nsh;
2319         LIST_HEAD(newstripes);
2320         struct disk_info *ndisks;
2321         int err = 0;
2322         struct kmem_cache *sc;
2323         int i;
2324         int hash, cnt;
2325
2326         md_allow_write(conf->mddev);
2327
2328         /* Step 1 */
2329         sc = kmem_cache_create(conf->cache_name[1-conf->active_name],
2330                                sizeof(struct stripe_head)+(newsize-1)*sizeof(struct r5dev),
2331                                0, 0, NULL);
2332         if (!sc)
2333                 return -ENOMEM;
2334
2335         /* Need to ensure auto-resizing doesn't interfere */
2336         mutex_lock(&conf->cache_size_mutex);
2337
2338         for (i = conf->max_nr_stripes; i; i--) {
2339                 nsh = alloc_stripe(sc, GFP_KERNEL, newsize, conf);
2340                 if (!nsh)
2341                         break;
2342
2343                 list_add(&nsh->lru, &newstripes);
2344         }
2345         if (i) {
2346                 /* didn't get enough, give up */
2347                 while (!list_empty(&newstripes)) {
2348                         nsh = list_entry(newstripes.next, struct stripe_head, lru);
2349                         list_del(&nsh->lru);
2350                         free_stripe(sc, nsh);
2351                 }
2352                 kmem_cache_destroy(sc);
2353                 mutex_unlock(&conf->cache_size_mutex);
2354                 return -ENOMEM;
2355         }
2356         /* Step 2 - Must use GFP_NOIO now.
2357          * OK, we have enough stripes, start collecting inactive
2358          * stripes and copying them over
2359          */
2360         hash = 0;
2361         cnt = 0;
2362         list_for_each_entry(nsh, &newstripes, lru) {
2363                 lock_device_hash_lock(conf, hash);
2364                 wait_event_cmd(conf->wait_for_stripe,
2365                                     !list_empty(conf->inactive_list + hash),
2366                                     unlock_device_hash_lock(conf, hash),
2367                                     lock_device_hash_lock(conf, hash));
2368                 osh = get_free_stripe(conf, hash);
2369                 unlock_device_hash_lock(conf, hash);
2370
2371                 for(i=0; i<conf->pool_size; i++) {
2372                         nsh->dev[i].page = osh->dev[i].page;
2373                         nsh->dev[i].orig_page = osh->dev[i].page;
2374                 }
2375                 nsh->hash_lock_index = hash;
2376                 free_stripe(conf->slab_cache, osh);
2377                 cnt++;
2378                 if (cnt >= conf->max_nr_stripes / NR_STRIPE_HASH_LOCKS +
2379                     !!((conf->max_nr_stripes % NR_STRIPE_HASH_LOCKS) > hash)) {
2380                         hash++;
2381                         cnt = 0;
2382                 }
2383         }
2384         kmem_cache_destroy(conf->slab_cache);
2385
2386         /* Step 3.
2387          * At this point, we are holding all the stripes so the array
2388          * is completely stalled, so now is a good time to resize
2389          * conf->disks and the scribble region
2390          */
2391         ndisks = kzalloc(newsize * sizeof(struct disk_info), GFP_NOIO);
2392         if (ndisks) {
2393                 for (i = 0; i < conf->pool_size; i++)
2394                         ndisks[i] = conf->disks[i];
2395
2396                 for (i = conf->pool_size; i < newsize; i++) {
2397                         ndisks[i].extra_page = alloc_page(GFP_NOIO);
2398                         if (!ndisks[i].extra_page)
2399                                 err = -ENOMEM;
2400                 }
2401
2402                 if (err) {
2403                         for (i = conf->pool_size; i < newsize; i++)
2404                                 if (ndisks[i].extra_page)
2405                                         put_page(ndisks[i].extra_page);
2406                         kfree(ndisks);
2407                 } else {
2408                         kfree(conf->disks);
2409                         conf->disks = ndisks;
2410                 }
2411         } else
2412                 err = -ENOMEM;
2413
2414         mutex_unlock(&conf->cache_size_mutex);
2415
2416         conf->slab_cache = sc;
2417         conf->active_name = 1-conf->active_name;
2418
2419         /* Step 4, return new stripes to service */
2420         while(!list_empty(&newstripes)) {
2421                 nsh = list_entry(newstripes.next, struct stripe_head, lru);
2422                 list_del_init(&nsh->lru);
2423
2424                 for (i=conf->raid_disks; i < newsize; i++)
2425                         if (nsh->dev[i].page == NULL) {
2426                                 struct page *p = alloc_page(GFP_NOIO);
2427                                 nsh->dev[i].page = p;
2428                                 nsh->dev[i].orig_page = p;
2429                                 if (!p)
2430                                         err = -ENOMEM;
2431                         }
2432                 raid5_release_stripe(nsh);
2433         }
2434         /* critical section pass, GFP_NOIO no longer needed */
2435
2436         if (!err)
2437                 conf->pool_size = newsize;
2438         return err;
2439 }
2440
2441 static int drop_one_stripe(struct r5conf *conf)
2442 {
2443         struct stripe_head *sh;
2444         int hash = (conf->max_nr_stripes - 1) & STRIPE_HASH_LOCKS_MASK;
2445
2446         spin_lock_irq(conf->hash_locks + hash);
2447         sh = get_free_stripe(conf, hash);
2448         spin_unlock_irq(conf->hash_locks + hash);
2449         if (!sh)
2450                 return 0;
2451         BUG_ON(atomic_read(&sh->count));
2452         shrink_buffers(sh);
2453         free_stripe(conf->slab_cache, sh);
2454         atomic_dec(&conf->active_stripes);
2455         conf->max_nr_stripes--;
2456         return 1;
2457 }
2458
2459 static void shrink_stripes(struct r5conf *conf)
2460 {
2461         while (conf->max_nr_stripes &&
2462                drop_one_stripe(conf))
2463                 ;
2464
2465         kmem_cache_destroy(conf->slab_cache);
2466         conf->slab_cache = NULL;
2467 }
2468
2469 static void raid5_end_read_request(struct bio * bi)
2470 {
2471         struct stripe_head *sh = bi->bi_private;
2472         struct r5conf *conf = sh->raid_conf;
2473         int disks = sh->disks, i;
2474         char b[BDEVNAME_SIZE];
2475         struct md_rdev *rdev = NULL;
2476         sector_t s;
2477
2478         for (i=0 ; i<disks; i++)
2479                 if (bi == &sh->dev[i].req)
2480                         break;
2481
2482         pr_debug("end_read_request %llu/%d, count: %d, error %d.\n",
2483                 (unsigned long long)sh->sector, i, atomic_read(&sh->count),
2484                 bi->bi_status);
2485         if (i == disks) {
2486                 bio_reset(bi);
2487                 BUG();
2488                 return;
2489         }
2490         if (test_bit(R5_ReadRepl, &sh->dev[i].flags))
2491                 /* If replacement finished while this request was outstanding,
2492                  * 'replacement' might be NULL already.
2493                  * In that case it moved down to 'rdev'.
2494                  * rdev is not removed until all requests are finished.
2495                  */
2496                 rdev = conf->disks[i].replacement;
2497         if (!rdev)
2498                 rdev = conf->disks[i].rdev;
2499
2500         if (use_new_offset(conf, sh))
2501                 s = sh->sector + rdev->new_data_offset;
2502         else
2503                 s = sh->sector + rdev->data_offset;
2504         if (!bi->bi_status) {
2505                 set_bit(R5_UPTODATE, &sh->dev[i].flags);
2506                 if (test_bit(R5_ReadError, &sh->dev[i].flags)) {
2507                         /* Note that this cannot happen on a
2508                          * replacement device.  We just fail those on
2509                          * any error
2510                          */
2511                         pr_info_ratelimited(
2512                                 "md/raid:%s: read error corrected (%lu sectors at %llu on %s)\n",
2513                                 mdname(conf->mddev), STRIPE_SECTORS,
2514                                 (unsigned long long)s,
2515                                 bdevname(rdev->bdev, b));
2516                         atomic_add(STRIPE_SECTORS, &rdev->corrected_errors);
2517                         clear_bit(R5_ReadError, &sh->dev[i].flags);
2518                         clear_bit(R5_ReWrite, &sh->dev[i].flags);
2519                 } else if (test_bit(R5_ReadNoMerge, &sh->dev[i].flags))
2520                         clear_bit(R5_ReadNoMerge, &sh->dev[i].flags);
2521
2522                 if (test_bit(R5_InJournal, &sh->dev[i].flags))
2523                         /*
2524                          * end read for a page in journal, this
2525                          * must be preparing for prexor in rmw
2526                          */
2527                         set_bit(R5_OrigPageUPTDODATE, &sh->dev[i].flags);
2528
2529                 if (atomic_read(&rdev->read_errors))
2530                         atomic_set(&rdev->read_errors, 0);
2531         } else {
2532                 const char *bdn = bdevname(rdev->bdev, b);
2533                 int retry = 0;
2534                 int set_bad = 0;
2535
2536                 clear_bit(R5_UPTODATE, &sh->dev[i].flags);
2537                 atomic_inc(&rdev->read_errors);
2538                 if (test_bit(R5_ReadRepl, &sh->dev[i].flags))
2539                         pr_warn_ratelimited(
2540                                 "md/raid:%s: read error on replacement device (sector %llu on %s).\n",
2541                                 mdname(conf->mddev),
2542                                 (unsigned long long)s,
2543                                 bdn);
2544                 else if (conf->mddev->degraded >= conf->max_degraded) {
2545                         set_bad = 1;
2546                         pr_warn_ratelimited(
2547                                 "md/raid:%s: read error not correctable (sector %llu on %s).\n",
2548                                 mdname(conf->mddev),
2549                                 (unsigned long long)s,
2550                                 bdn);
2551                 } else if (test_bit(R5_ReWrite, &sh->dev[i].flags)) {
2552                         /* Oh, no!!! */
2553                         set_bad = 1;
2554                         pr_warn_ratelimited(
2555                                 "md/raid:%s: read error NOT corrected!! (sector %llu on %s).\n",
2556                                 mdname(conf->mddev),
2557                                 (unsigned long long)s,
2558                                 bdn);
2559                 } else if (atomic_read(&rdev->read_errors)
2560                          > conf->max_nr_stripes)
2561                         pr_warn("md/raid:%s: Too many read errors, failing device %s.\n",
2562                                mdname(conf->mddev), bdn);
2563                 else
2564                         retry = 1;
2565                 if (set_bad && test_bit(In_sync, &rdev->flags)
2566                     && !test_bit(R5_ReadNoMerge, &sh->dev[i].flags))
2567                         retry = 1;
2568                 if (retry)
2569                         if (test_bit(R5_ReadNoMerge, &sh->dev[i].flags)) {
2570                                 set_bit(R5_ReadError, &sh->dev[i].flags);
2571                                 clear_bit(R5_ReadNoMerge, &sh->dev[i].flags);
2572                         } else
2573                                 set_bit(R5_ReadNoMerge, &sh->dev[i].flags);
2574                 else {
2575                         clear_bit(R5_ReadError, &sh->dev[i].flags);
2576                         clear_bit(R5_ReWrite, &sh->dev[i].flags);
2577                         if (!(set_bad
2578                               && test_bit(In_sync, &rdev->flags)
2579                               && rdev_set_badblocks(
2580                                       rdev, sh->sector, STRIPE_SECTORS, 0)))
2581                                 md_error(conf->mddev, rdev);
2582                 }
2583         }
2584         rdev_dec_pending(rdev, conf->mddev);
2585         bio_reset(bi);
2586         clear_bit(R5_LOCKED, &sh->dev[i].flags);
2587         set_bit(STRIPE_HANDLE, &sh->state);
2588         raid5_release_stripe(sh);
2589 }
2590
2591 static void raid5_end_write_request(struct bio *bi)
2592 {
2593         struct stripe_head *sh = bi->bi_private;
2594         struct r5conf *conf = sh->raid_conf;
2595         int disks = sh->disks, i;
2596         struct md_rdev *uninitialized_var(rdev);
2597         sector_t first_bad;
2598         int bad_sectors;
2599         int replacement = 0;
2600
2601         for (i = 0 ; i < disks; i++) {
2602                 if (bi == &sh->dev[i].req) {
2603                         rdev = conf->disks[i].rdev;
2604                         break;
2605                 }
2606                 if (bi == &sh->dev[i].rreq) {
2607                         rdev = conf->disks[i].replacement;
2608                         if (rdev)
2609                                 replacement = 1;
2610                         else
2611                                 /* rdev was removed and 'replacement'
2612                                  * replaced it.  rdev is not removed
2613                                  * until all requests are finished.
2614                                  */
2615                                 rdev = conf->disks[i].rdev;
2616                         break;
2617                 }
2618         }
2619         pr_debug("end_write_request %llu/%d, count %d, error: %d.\n",
2620                 (unsigned long long)sh->sector, i, atomic_read(&sh->count),
2621                 bi->bi_status);
2622         if (i == disks) {
2623                 bio_reset(bi);
2624                 BUG();
2625                 return;
2626         }
2627
2628         if (replacement) {
2629                 if (bi->bi_status)
2630                         md_error(conf->mddev, rdev);
2631                 else if (is_badblock(rdev, sh->sector,
2632                                      STRIPE_SECTORS,
2633                                      &first_bad, &bad_sectors))
2634                         set_bit(R5_MadeGoodRepl, &sh->dev[i].flags);
2635         } else {
2636                 if (bi->bi_status) {
2637                         set_bit(STRIPE_DEGRADED, &sh->state);
2638                         set_bit(WriteErrorSeen, &rdev->flags);
2639                         set_bit(R5_WriteError, &sh->dev[i].flags);
2640                         if (!test_and_set_bit(WantReplacement, &rdev->flags))
2641                                 set_bit(MD_RECOVERY_NEEDED,
2642                                         &rdev->mddev->recovery);
2643                 } else if (is_badblock(rdev, sh->sector,
2644                                        STRIPE_SECTORS,
2645                                        &first_bad, &bad_sectors)) {
2646                         set_bit(R5_MadeGood, &sh->dev[i].flags);
2647                         if (test_bit(R5_ReadError, &sh->dev[i].flags))
2648                                 /* That was a successful write so make
2649                                  * sure it looks like we already did
2650                                  * a re-write.
2651                                  */
2652                                 set_bit(R5_ReWrite, &sh->dev[i].flags);
2653                 }
2654         }
2655         rdev_dec_pending(rdev, conf->mddev);
2656
2657         if (sh->batch_head && bi->bi_status && !replacement)
2658                 set_bit(STRIPE_BATCH_ERR, &sh->batch_head->state);
2659
2660         bio_reset(bi);
2661         if (!test_and_clear_bit(R5_DOUBLE_LOCKED, &sh->dev[i].flags))
2662                 clear_bit(R5_LOCKED, &sh->dev[i].flags);
2663         set_bit(STRIPE_HANDLE, &sh->state);
2664         raid5_release_stripe(sh);
2665
2666         if (sh->batch_head && sh != sh->batch_head)
2667                 raid5_release_stripe(sh->batch_head);
2668 }
2669
2670 static void raid5_error(struct mddev *mddev, struct md_rdev *rdev)
2671 {
2672         char b[BDEVNAME_SIZE];
2673         struct r5conf *conf = mddev->private;
2674         unsigned long flags;
2675         pr_debug("raid456: error called\n");
2676
2677         spin_lock_irqsave(&conf->device_lock, flags);
2678         clear_bit(In_sync, &rdev->flags);
2679         mddev->degraded = raid5_calc_degraded(conf);
2680         spin_unlock_irqrestore(&conf->device_lock, flags);
2681         set_bit(MD_RECOVERY_INTR, &mddev->recovery);
2682
2683         set_bit(Blocked, &rdev->flags);
2684         set_bit(Faulty, &rdev->flags);
2685         set_mask_bits(&mddev->sb_flags, 0,
2686                       BIT(MD_SB_CHANGE_DEVS) | BIT(MD_SB_CHANGE_PENDING));
2687         pr_crit("md/raid:%s: Disk failure on %s, disabling device.\n"
2688                 "md/raid:%s: Operation continuing on %d devices.\n",
2689                 mdname(mddev),
2690                 bdevname(rdev->bdev, b),
2691                 mdname(mddev),
2692                 conf->raid_disks - mddev->degraded);
2693         r5c_update_on_rdev_error(mddev, rdev);
2694 }
2695
2696 /*
2697  * Input: a 'big' sector number,
2698  * Output: index of the data and parity disk, and the sector # in them.
2699  */
2700 sector_t raid5_compute_sector(struct r5conf *conf, sector_t r_sector,
2701                               int previous, int *dd_idx,
2702                               struct stripe_head *sh)
2703 {
2704         sector_t stripe, stripe2;
2705         sector_t chunk_number;
2706         unsigned int chunk_offset;
2707         int pd_idx, qd_idx;
2708         int ddf_layout = 0;
2709         sector_t new_sector;
2710         int algorithm = previous ? conf->prev_algo
2711                                  : conf->algorithm;
2712         int sectors_per_chunk = previous ? conf->prev_chunk_sectors
2713                                          : conf->chunk_sectors;
2714         int raid_disks = previous ? conf->previous_raid_disks
2715                                   : conf->raid_disks;
2716         int data_disks = raid_disks - conf->max_degraded;
2717
2718         /* First compute the information on this sector */
2719
2720         /*
2721          * Compute the chunk number and the sector offset inside the chunk
2722          */
2723         chunk_offset = sector_div(r_sector, sectors_per_chunk);
2724         chunk_number = r_sector;
2725
2726         /*
2727          * Compute the stripe number
2728          */
2729         stripe = chunk_number;
2730         *dd_idx = sector_div(stripe, data_disks);
2731         stripe2 = stripe;
2732         /*
2733          * Select the parity disk based on the user selected algorithm.
2734          */
2735         pd_idx = qd_idx = -1;
2736         switch(conf->level) {
2737         case 4:
2738                 pd_idx = data_disks;
2739                 break;
2740         case 5:
2741                 switch (algorithm) {
2742                 case ALGORITHM_LEFT_ASYMMETRIC:
2743                         pd_idx = data_disks - sector_div(stripe2, raid_disks);
2744                         if (*dd_idx >= pd_idx)
2745                                 (*dd_idx)++;
2746                         break;
2747                 case ALGORITHM_RIGHT_ASYMMETRIC:
2748                         pd_idx = sector_div(stripe2, raid_disks);
2749                         if (*dd_idx >= pd_idx)
2750                                 (*dd_idx)++;
2751                         break;
2752                 case ALGORITHM_LEFT_SYMMETRIC:
2753                         pd_idx = data_disks - sector_div(stripe2, raid_disks);
2754                         *dd_idx = (pd_idx + 1 + *dd_idx) % raid_disks;
2755                         break;
2756                 case ALGORITHM_RIGHT_SYMMETRIC:
2757                         pd_idx = sector_div(stripe2, raid_disks);
2758                         *dd_idx = (pd_idx + 1 + *dd_idx) % raid_disks;
2759                         break;
2760                 case ALGORITHM_PARITY_0:
2761                         pd_idx = 0;
2762                         (*dd_idx)++;
2763                         break;
2764                 case ALGORITHM_PARITY_N:
2765                         pd_idx = data_disks;
2766                         break;
2767                 default:
2768                         BUG();
2769                 }
2770                 break;
2771         case 6:
2772
2773                 switch (algorithm) {
2774                 case ALGORITHM_LEFT_ASYMMETRIC:
2775                         pd_idx = raid_disks - 1 - sector_div(stripe2, raid_disks);
2776                         qd_idx = pd_idx + 1;
2777                         if (pd_idx == raid_disks-1) {
2778                                 (*dd_idx)++;    /* Q D D D P */
2779                                 qd_idx = 0;
2780                         } else if (*dd_idx >= pd_idx)
2781                                 (*dd_idx) += 2; /* D D P Q D */
2782                         break;
2783                 case ALGORITHM_RIGHT_ASYMMETRIC:
2784                         pd_idx = sector_div(stripe2, raid_disks);
2785                         qd_idx = pd_idx + 1;
2786                         if (pd_idx == raid_disks-1) {
2787                                 (*dd_idx)++;    /* Q D D D P */
2788                                 qd_idx = 0;
2789                         } else if (*dd_idx >= pd_idx)
2790                                 (*dd_idx) += 2; /* D D P Q D */
2791                         break;
2792                 case ALGORITHM_LEFT_SYMMETRIC:
2793                         pd_idx = raid_disks - 1 - sector_div(stripe2, raid_disks);
2794                         qd_idx = (pd_idx + 1) % raid_disks;
2795                         *dd_idx = (pd_idx + 2 + *dd_idx) % raid_disks;
2796                         break;
2797                 case ALGORITHM_RIGHT_SYMMETRIC:
2798                         pd_idx = sector_div(stripe2, raid_disks);
2799                         qd_idx = (pd_idx + 1) % raid_disks;
2800                         *dd_idx = (pd_idx + 2 + *dd_idx) % raid_disks;
2801                         break;
2802
2803                 case ALGORITHM_PARITY_0:
2804                         pd_idx = 0;
2805                         qd_idx = 1;
2806                         (*dd_idx) += 2;
2807                         break;
2808                 case ALGORITHM_PARITY_N:
2809                         pd_idx = data_disks;
2810                         qd_idx = data_disks + 1;
2811                         break;
2812
2813                 case ALGORITHM_ROTATING_ZERO_RESTART:
2814                         /* Exactly the same as RIGHT_ASYMMETRIC, but or
2815                          * of blocks for computing Q is different.
2816                          */
2817                         pd_idx = sector_div(stripe2, raid_disks);
2818                         qd_idx = pd_idx + 1;
2819                         if (pd_idx == raid_disks-1) {
2820                                 (*dd_idx)++;    /* Q D D D P */
2821                                 qd_idx = 0;
2822                         } else if (*dd_idx >= pd_idx)
2823                                 (*dd_idx) += 2; /* D D P Q D */
2824                         ddf_layout = 1;
2825                         break;
2826
2827                 case ALGORITHM_ROTATING_N_RESTART:
2828                         /* Same a left_asymmetric, by first stripe is
2829                          * D D D P Q  rather than
2830                          * Q D D D P
2831                          */
2832                         stripe2 += 1;
2833                         pd_idx = raid_disks - 1 - sector_div(stripe2, raid_disks);
2834                         qd_idx = pd_idx + 1;
2835                         if (pd_idx == raid_disks-1) {
2836                                 (*dd_idx)++;    /* Q D D D P */
2837                                 qd_idx = 0;
2838                         } else if (*dd_idx >= pd_idx)
2839                                 (*dd_idx) += 2; /* D D P Q D */
2840                         ddf_layout = 1;
2841                         break;
2842
2843                 case ALGORITHM_ROTATING_N_CONTINUE:
2844                         /* Same as left_symmetric but Q is before P */
2845                         pd_idx = raid_disks - 1 - sector_div(stripe2, raid_disks);
2846                         qd_idx = (pd_idx + raid_disks - 1) % raid_disks;
2847                         *dd_idx = (pd_idx + 1 + *dd_idx) % raid_disks;
2848                         ddf_layout = 1;
2849                         break;
2850
2851                 case ALGORITHM_LEFT_ASYMMETRIC_6:
2852                         /* RAID5 left_asymmetric, with Q on last device */
2853                         pd_idx = data_disks - sector_div(stripe2, raid_disks-1);
2854                         if (*dd_idx >= pd_idx)
2855                                 (*dd_idx)++;
2856                         qd_idx = raid_disks - 1;
2857                         break;
2858
2859                 case ALGORITHM_RIGHT_ASYMMETRIC_6:
2860                         pd_idx = sector_div(stripe2, raid_disks-1);
2861                         if (*dd_idx >= pd_idx)
2862                                 (*dd_idx)++;
2863                         qd_idx = raid_disks - 1;
2864                         break;
2865
2866                 case ALGORITHM_LEFT_SYMMETRIC_6:
2867                         pd_idx = data_disks - sector_div(stripe2, raid_disks-1);
2868                         *dd_idx = (pd_idx + 1 + *dd_idx) % (raid_disks-1);
2869                         qd_idx = raid_disks - 1;
2870                         break;
2871
2872                 case ALGORITHM_RIGHT_SYMMETRIC_6:
2873                         pd_idx = sector_div(stripe2, raid_disks-1);
2874                         *dd_idx = (pd_idx + 1 + *dd_idx) % (raid_disks-1);
2875                         qd_idx = raid_disks - 1;
2876                         break;
2877
2878                 case ALGORITHM_PARITY_0_6:
2879                         pd_idx = 0;
2880                         (*dd_idx)++;
2881                         qd_idx = raid_disks - 1;
2882                         break;
2883
2884                 default:
2885                         BUG();
2886                 }
2887                 break;
2888         }
2889
2890         if (sh) {
2891                 sh->pd_idx = pd_idx;
2892                 sh->qd_idx = qd_idx;
2893                 sh->ddf_layout = ddf_layout;
2894         }
2895         /*
2896          * Finally, compute the new sector number
2897          */
2898         new_sector = (sector_t)stripe * sectors_per_chunk + chunk_offset;
2899         return new_sector;
2900 }
2901
2902 sector_t raid5_compute_blocknr(struct stripe_head *sh, int i, int previous)
2903 {
2904         struct r5conf *conf = sh->raid_conf;
2905         int raid_disks = sh->disks;
2906         int data_disks = raid_disks - conf->max_degraded;
2907         sector_t new_sector = sh->sector, check;
2908         int sectors_per_chunk = previous ? conf->prev_chunk_sectors
2909                                          : conf->chunk_sectors;
2910         int algorithm = previous ? conf->prev_algo
2911                                  : conf->algorithm;
2912         sector_t stripe;
2913         int chunk_offset;
2914         sector_t chunk_number;
2915         int dummy1, dd_idx = i;
2916         sector_t r_sector;
2917         struct stripe_head sh2;
2918
2919         chunk_offset = sector_div(new_sector, sectors_per_chunk);
2920         stripe = new_sector;
2921
2922         if (i == sh->pd_idx)
2923                 return 0;
2924         switch(conf->level) {
2925         case 4: break;
2926         case 5:
2927                 switch (algorithm) {
2928                 case ALGORITHM_LEFT_ASYMMETRIC:
2929                 case ALGORITHM_RIGHT_ASYMMETRIC:
2930                         if (i > sh->pd_idx)
2931                                 i--;
2932                         break;
2933                 case ALGORITHM_LEFT_SYMMETRIC:
2934                 case ALGORITHM_RIGHT_SYMMETRIC:
2935                         if (i < sh->pd_idx)
2936                                 i += raid_disks;
2937                         i -= (sh->pd_idx + 1);
2938                         break;
2939                 case ALGORITHM_PARITY_0:
2940                         i -= 1;
2941                         break;
2942                 case ALGORITHM_PARITY_N:
2943                         break;
2944                 default:
2945                         BUG();
2946                 }
2947                 break;
2948         case 6:
2949                 if (i == sh->qd_idx)
2950                         return 0; /* It is the Q disk */
2951                 switch (algorithm) {
2952                 case ALGORITHM_LEFT_ASYMMETRIC:
2953                 case ALGORITHM_RIGHT_ASYMMETRIC:
2954                 case ALGORITHM_ROTATING_ZERO_RESTART:
2955                 case ALGORITHM_ROTATING_N_RESTART:
2956                         if (sh->pd_idx == raid_disks-1)
2957                                 i--;    /* Q D D D P */
2958                         else if (i > sh->pd_idx)
2959                                 i -= 2; /* D D P Q D */
2960                         break;
2961                 case ALGORITHM_LEFT_SYMMETRIC:
2962                 case ALGORITHM_RIGHT_SYMMETRIC:
2963                         if (sh->pd_idx == raid_disks-1)
2964                                 i--; /* Q D D D P */
2965                         else {
2966                                 /* D D P Q D */
2967                                 if (i < sh->pd_idx)
2968                                         i += raid_disks;
2969                                 i -= (sh->pd_idx + 2);
2970                         }
2971                         break;
2972                 case ALGORITHM_PARITY_0:
2973                         i -= 2;
2974                         break;
2975                 case ALGORITHM_PARITY_N:
2976                         break;
2977                 case ALGORITHM_ROTATING_N_CONTINUE:
2978                         /* Like left_symmetric, but P is before Q */
2979                         if (sh->pd_idx == 0)
2980                                 i--;    /* P D D D Q */
2981                         else {
2982                                 /* D D Q P D */
2983                                 if (i < sh->pd_idx)
2984                                         i += raid_disks;
2985                                 i -= (sh->pd_idx + 1);
2986                         }
2987                         break;
2988                 case ALGORITHM_LEFT_ASYMMETRIC_6:
2989                 case ALGORITHM_RIGHT_ASYMMETRIC_6:
2990                         if (i > sh->pd_idx)
2991                                 i--;
2992                         break;
2993                 case ALGORITHM_LEFT_SYMMETRIC_6:
2994                 case ALGORITHM_RIGHT_SYMMETRIC_6:
2995                         if (i < sh->pd_idx)
2996                                 i += data_disks + 1;
2997                         i -= (sh->pd_idx + 1);
2998                         break;
2999                 case ALGORITHM_PARITY_0_6:
3000                         i -= 1;
3001                         break;
3002                 default:
3003                         BUG();
3004                 }
3005                 break;
3006         }
3007
3008         chunk_number = stripe * data_disks + i;
3009         r_sector = chunk_number * sectors_per_chunk + chunk_offset;
3010
3011         check = raid5_compute_sector(conf, r_sector,
3012                                      previous, &dummy1, &sh2);
3013         if (check != sh->sector || dummy1 != dd_idx || sh2.pd_idx != sh->pd_idx
3014                 || sh2.qd_idx != sh->qd_idx) {
3015                 pr_warn("md/raid:%s: compute_blocknr: map not correct\n",
3016                         mdname(conf->mddev));
3017                 return 0;
3018         }
3019         return r_sector;
3020 }
3021
3022 /*
3023  * There are cases where we want handle_stripe_dirtying() and
3024  * schedule_reconstruction() to delay towrite to some dev of a stripe.
3025  *
3026  * This function checks whether we want to delay the towrite. Specifically,
3027  * we delay the towrite when:
3028  *
3029  *   1. degraded stripe has a non-overwrite to the missing dev, AND this
3030  *      stripe has data in journal (for other devices).
3031  *
3032  *      In this case, when reading data for the non-overwrite dev, it is
3033  *      necessary to handle complex rmw of write back cache (prexor with
3034  *      orig_page, and xor with page). To keep read path simple, we would
3035  *      like to flush data in journal to RAID disks first, so complex rmw
3036  *      is handled in the write patch (handle_stripe_dirtying).
3037  *
3038  *   2. when journal space is critical (R5C_LOG_CRITICAL=1)
3039  *
3040  *      It is important to be able to flush all stripes in raid5-cache.
3041  *      Therefore, we need reserve some space on the journal device for
3042  *      these flushes. If flush operation includes pending writes to the
3043  *      stripe, we need to reserve (conf->raid_disk + 1) pages per stripe
3044  *      for the flush out. If we exclude these pending writes from flush
3045  *      operation, we only need (conf->max_degraded + 1) pages per stripe.
3046  *      Therefore, excluding pending writes in these cases enables more
3047  *      efficient use of the journal device.
3048  *
3049  *      Note: To make sure the stripe makes progress, we only delay
3050  *      towrite for stripes with data already in journal (injournal > 0).
3051  *      When LOG_CRITICAL, stripes with injournal == 0 will be sent to
3052  *      no_space_stripes list.
3053  *
3054  *   3. during journal failure
3055  *      In journal failure, we try to flush all cached data to raid disks
3056  *      based on data in stripe cache. The array is read-only to upper
3057  *      layers, so we would skip all pending writes.
3058  *
3059  */
3060 static inline bool delay_towrite(struct r5conf *conf,
3061                                  struct r5dev *dev,
3062                                  struct stripe_head_state *s)
3063 {
3064         /* case 1 above */
3065         if (!test_bit(R5_OVERWRITE, &dev->flags) &&
3066             !test_bit(R5_Insync, &dev->flags) && s->injournal)
3067                 return true;
3068         /* case 2 above */
3069         if (test_bit(R5C_LOG_CRITICAL, &conf->cache_state) &&
3070             s->injournal > 0)
3071                 return true;
3072         /* case 3 above */
3073         if (s->log_failed && s->injournal)
3074                 return true;
3075         return false;
3076 }
3077
3078 static void
3079 schedule_reconstruction(struct stripe_head *sh, struct stripe_head_state *s,
3080                          int rcw, int expand)
3081 {
3082         int i, pd_idx = sh->pd_idx, qd_idx = sh->qd_idx, disks = sh->disks;
3083         struct r5conf *conf = sh->raid_conf;
3084         int level = conf->level;
3085
3086         if (rcw) {
3087                 /*
3088                  * In some cases, handle_stripe_dirtying initially decided to
3089                  * run rmw and allocates extra page for prexor. However, rcw is
3090                  * cheaper later on. We need to free the extra page now,
3091                  * because we won't be able to do that in ops_complete_prexor().
3092                  */
3093                 r5c_release_extra_page(sh);
3094
3095                 for (i = disks; i--; ) {
3096                         struct r5dev *dev = &sh->dev[i];
3097
3098                         if (dev->towrite && !delay_towrite(conf, dev, s)) {
3099                                 set_bit(R5_LOCKED, &dev->flags);
3100                                 set_bit(R5_Wantdrain, &dev->flags);
3101                                 if (!expand)
3102                                         clear_bit(R5_UPTODATE, &dev->flags);
3103                                 s->locked++;
3104                         } else if (test_bit(R5_InJournal, &dev->flags)) {
3105                                 set_bit(R5_LOCKED, &dev->flags);
3106                                 s->locked++;
3107                         }
3108                 }
3109                 /* if we are not expanding this is a proper write request, and
3110                  * there will be bios with new data to be drained into the
3111                  * stripe cache
3112                  */
3113                 if (!expand) {
3114                         if (!s->locked)
3115                                 /* False alarm, nothing to do */
3116                                 return;
3117                         sh->reconstruct_state = reconstruct_state_drain_run;
3118                         set_bit(STRIPE_OP_BIODRAIN, &s->ops_request);
3119                 } else
3120                         sh->reconstruct_state = reconstruct_state_run;
3121
3122                 set_bit(STRIPE_OP_RECONSTRUCT, &s->ops_request);
3123
3124                 if (s->locked + conf->max_degraded == disks)
3125                         if (!test_and_set_bit(STRIPE_FULL_WRITE, &sh->state))
3126                                 atomic_inc(&conf->pending_full_writes);
3127         } else {
3128                 BUG_ON(!(test_bit(R5_UPTODATE, &sh->dev[pd_idx].flags) ||
3129                         test_bit(R5_Wantcompute, &sh->dev[pd_idx].flags)));
3130                 BUG_ON(level == 6 &&
3131                         (!(test_bit(R5_UPTODATE, &sh->dev[qd_idx].flags) ||
3132                            test_bit(R5_Wantcompute, &sh->dev[qd_idx].flags))));
3133
3134                 for (i = disks; i--; ) {
3135                         struct r5dev *dev = &sh->dev[i];
3136                         if (i == pd_idx || i == qd_idx)
3137                                 continue;
3138
3139                         if (dev->towrite &&
3140                             (test_bit(R5_UPTODATE, &dev->flags) ||
3141                              test_bit(R5_Wantcompute, &dev->flags))) {
3142                                 set_bit(R5_Wantdrain, &dev->flags);
3143                                 set_bit(R5_LOCKED, &dev->flags);
3144                                 clear_bit(R5_UPTODATE, &dev->flags);
3145                                 s->locked++;
3146                         } else if (test_bit(R5_InJournal, &dev->flags)) {
3147                                 set_bit(R5_LOCKED, &dev->flags);
3148                                 s->locked++;
3149                         }
3150                 }
3151                 if (!s->locked)
3152                         /* False alarm - nothing to do */
3153                         return;
3154                 sh->reconstruct_state = reconstruct_state_prexor_drain_run;
3155                 set_bit(STRIPE_OP_PREXOR, &s->ops_request);
3156                 set_bit(STRIPE_OP_BIODRAIN, &s->ops_request);
3157                 set_bit(STRIPE_OP_RECONSTRUCT, &s->ops_request);
3158         }
3159
3160         /* keep the parity disk(s) locked while asynchronous operations
3161          * are in flight
3162          */
3163         set_bit(R5_LOCKED, &sh->dev[pd_idx].flags);
3164         clear_bit(R5_UPTODATE, &sh->dev[pd_idx].flags);
3165         s->locked++;
3166
3167         if (level == 6) {
3168                 int qd_idx = sh->qd_idx;
3169                 struct r5dev *dev = &sh->dev[qd_idx];
3170
3171                 set_bit(R5_LOCKED, &dev->flags);
3172                 clear_bit(R5_UPTODATE, &dev->flags);
3173                 s->locked++;
3174         }
3175
3176         if (raid5_has_ppl(sh->raid_conf) && sh->ppl_page &&
3177             test_bit(STRIPE_OP_BIODRAIN, &s->ops_request) &&
3178             !test_bit(STRIPE_FULL_WRITE, &sh->state) &&
3179             test_bit(R5_Insync, &sh->dev[pd_idx].flags))
3180                 set_bit(STRIPE_OP_PARTIAL_PARITY, &s->ops_request);
3181
3182         pr_debug("%s: stripe %llu locked: %d ops_request: %lx\n",
3183                 __func__, (unsigned long long)sh->sector,
3184                 s->locked, s->ops_request);
3185 }
3186
3187 /*
3188  * Each stripe/dev can have one or more bion attached.
3189  * toread/towrite point to the first in a chain.
3190  * The bi_next chain must be in order.
3191  */
3192 static int add_stripe_bio(struct stripe_head *sh, struct bio *bi, int dd_idx,
3193                           int forwrite, int previous)
3194 {
3195         struct bio **bip;
3196         struct r5conf *conf = sh->raid_conf;
3197         int firstwrite=0;
3198
3199         pr_debug("adding bi b#%llu to stripe s#%llu\n",
3200                 (unsigned long long)bi->bi_iter.bi_sector,
3201                 (unsigned long long)sh->sector);
3202
3203         spin_lock_irq(&sh->stripe_lock);
3204         /* Don't allow new IO added to stripes in batch list */
3205         if (sh->batch_head)
3206                 goto overlap;
3207         if (forwrite) {
3208                 bip = &sh->dev[dd_idx].towrite;
3209                 if (*bip == NULL)
3210                         firstwrite = 1;
3211         } else
3212                 bip = &sh->dev[dd_idx].toread;
3213         while (*bip && (*bip)->bi_iter.bi_sector < bi->bi_iter.bi_sector) {
3214                 if (bio_end_sector(*bip) > bi->bi_iter.bi_sector)
3215                         goto overlap;
3216                 bip = & (*bip)->bi_next;
3217         }
3218         if (*bip && (*bip)->bi_iter.bi_sector < bio_end_sector(bi))
3219                 goto overlap;
3220
3221         if (forwrite && raid5_has_ppl(conf)) {
3222                 /*
3223                  * With PPL only writes to consecutive data chunks within a
3224                  * stripe are allowed because for a single stripe_head we can
3225                  * only have one PPL entry at a time, which describes one data
3226                  * range. Not really an overlap, but wait_for_overlap can be
3227                  * used to handle this.
3228                  */
3229                 sector_t sector;
3230                 sector_t first = 0;
3231                 sector_t last = 0;
3232                 int count = 0;
3233                 int i;
3234
3235                 for (i = 0; i < sh->disks; i++) {
3236                         if (i != sh->pd_idx &&
3237                             (i == dd_idx || sh->dev[i].towrite)) {
3238                                 sector = sh->dev[i].sector;
3239                                 if (count == 0 || sector < first)
3240                                         first = sector;
3241                                 if (sector > last)
3242                                         last = sector;
3243                                 count++;
3244                         }
3245                 }
3246
3247                 if (first + conf->chunk_sectors * (count - 1) != last)
3248                         goto overlap;
3249         }
3250
3251         if (!forwrite || previous)
3252                 clear_bit(STRIPE_BATCH_READY, &sh->state);
3253
3254         BUG_ON(*bip && bi->bi_next && (*bip) != bi->bi_next);
3255         if (*bip)
3256                 bi->bi_next = *bip;
3257         *bip = bi;
3258         bio_inc_remaining(bi);
3259         md_write_inc(conf->mddev, bi);
3260
3261         if (forwrite) {
3262                 /* check if page is covered */
3263                 sector_t sector = sh->dev[dd_idx].sector;
3264                 for (bi=sh->dev[dd_idx].towrite;
3265                      sector < sh->dev[dd_idx].sector + STRIPE_SECTORS &&
3266                              bi && bi->bi_iter.bi_sector <= sector;
3267                      bi = r5_next_bio(bi, sh->dev[dd_idx].sector)) {
3268                         if (bio_end_sector(bi) >= sector)
3269                                 sector = bio_end_sector(bi);
3270                 }
3271                 if (sector >= sh->dev[dd_idx].sector + STRIPE_SECTORS)
3272                         if (!test_and_set_bit(R5_OVERWRITE, &sh->dev[dd_idx].flags))
3273                                 sh->overwrite_disks++;
3274         }
3275
3276         pr_debug("added bi b#%llu to stripe s#%llu, disk %d.\n",
3277                 (unsigned long long)(*bip)->bi_iter.bi_sector,
3278                 (unsigned long long)sh->sector, dd_idx);
3279
3280         if (conf->mddev->bitmap && firstwrite) {
3281                 /* Cannot hold spinlock over bitmap_startwrite,
3282                  * but must ensure this isn't added to a batch until
3283                  * we have added to the bitmap and set bm_seq.
3284                  * So set STRIPE_BITMAP_PENDING to prevent
3285                  * batching.
3286                  * If multiple add_stripe_bio() calls race here they
3287                  * much all set STRIPE_BITMAP_PENDING.  So only the first one
3288                  * to complete "bitmap_startwrite" gets to set
3289                  * STRIPE_BIT_DELAY.  This is important as once a stripe
3290                  * is added to a batch, STRIPE_BIT_DELAY cannot be changed
3291                  * any more.
3292                  */
3293                 set_bit(STRIPE_BITMAP_PENDING, &sh->state);
3294                 spin_unlock_irq(&sh->stripe_lock);
3295                 bitmap_startwrite(conf->mddev->bitmap, sh->sector,
3296                                   STRIPE_SECTORS, 0);
3297                 spin_lock_irq(&sh->stripe_lock);
3298                 clear_bit(STRIPE_BITMAP_PENDING, &sh->state);
3299                 if (!sh->batch_head) {
3300                         sh->bm_seq = conf->seq_flush+1;
3301                         set_bit(STRIPE_BIT_DELAY, &sh->state);
3302                 }
3303         }
3304         spin_unlock_irq(&sh->stripe_lock);
3305
3306         if (stripe_can_batch(sh))
3307                 stripe_add_to_batch_list(conf, sh);
3308         return 1;
3309
3310  overlap:
3311         set_bit(R5_Overlap, &sh->dev[dd_idx].flags);
3312         spin_unlock_irq(&sh->stripe_lock);
3313         return 0;
3314 }
3315
3316 static void end_reshape(struct r5conf *conf);
3317
3318 static void stripe_set_idx(sector_t stripe, struct r5conf *conf, int previous,
3319                             struct stripe_head *sh)
3320 {
3321         int sectors_per_chunk =
3322                 previous ? conf->prev_chunk_sectors : conf->chunk_sectors;
3323         int dd_idx;
3324         int chunk_offset = sector_div(stripe, sectors_per_chunk);
3325         int disks = previous ? conf->previous_raid_disks : conf->raid_disks;
3326
3327         raid5_compute_sector(conf,
3328                              stripe * (disks - conf->max_degraded)
3329                              *sectors_per_chunk + chunk_offset,
3330                              previous,
3331                              &dd_idx, sh);
3332 }
3333
3334 static void
3335 handle_failed_stripe(struct r5conf *conf, struct stripe_head *sh,
3336                      struct stripe_head_state *s, int disks)
3337 {
3338         int i;
3339         BUG_ON(sh->batch_head);
3340         for (i = disks; i--; ) {
3341                 struct bio *bi;
3342                 int bitmap_end = 0;
3343
3344                 if (test_bit(R5_ReadError, &sh->dev[i].flags)) {
3345                         struct md_rdev *rdev;
3346                         rcu_read_lock();
3347                         rdev = rcu_dereference(conf->disks[i].rdev);
3348                         if (rdev && test_bit(In_sync, &rdev->flags) &&
3349                             !test_bit(Faulty, &rdev->flags))
3350                                 atomic_inc(&rdev->nr_pending);
3351                         else
3352                                 rdev = NULL;
3353                         rcu_read_unlock();
3354                         if (rdev) {
3355                                 if (!rdev_set_badblocks(
3356                                             rdev,
3357                                             sh->sector,
3358                                             STRIPE_SECTORS, 0))
3359                                         md_error(conf->mddev, rdev);
3360                                 rdev_dec_pending(rdev, conf->mddev);
3361                         }
3362                 }
3363                 spin_lock_irq(&sh->stripe_lock);
3364                 /* fail all writes first */
3365                 bi = sh->dev[i].towrite;
3366                 sh->dev[i].towrite = NULL;
3367                 sh->overwrite_disks = 0;
3368                 spin_unlock_irq(&sh->stripe_lock);
3369                 if (bi)
3370                         bitmap_end = 1;
3371
3372                 log_stripe_write_finished(sh);
3373
3374                 if (test_and_clear_bit(R5_Overlap, &sh->dev[i].flags))
3375                         wake_up(&conf->wait_for_overlap);
3376
3377                 while (bi && bi->bi_iter.bi_sector <
3378                         sh->dev[i].sector + STRIPE_SECTORS) {
3379                         struct bio *nextbi = r5_next_bio(bi, sh->dev[i].sector);
3380
3381                         md_write_end(conf->mddev);
3382                         bio_io_error(bi);
3383                         bi = nextbi;
3384                 }
3385                 if (bitmap_end)
3386                         bitmap_endwrite(conf->mddev->bitmap, sh->sector,
3387                                 STRIPE_SECTORS, 0, 0);
3388                 bitmap_end = 0;
3389                 /* and fail all 'written' */
3390                 bi = sh->dev[i].written;
3391                 sh->dev[i].written = NULL;
3392                 if (test_and_clear_bit(R5_SkipCopy, &sh->dev[i].flags)) {
3393                         WARN_ON(test_bit(R5_UPTODATE, &sh->dev[i].flags));
3394                         sh->dev[i].page = sh->dev[i].orig_page;
3395                 }
3396
3397                 if (bi) bitmap_end = 1;
3398                 while (bi && bi->bi_iter.bi_sector <
3399                        sh->dev[i].sector + STRIPE_SECTORS) {
3400                         struct bio *bi2 = r5_next_bio(bi, sh->dev[i].sector);
3401
3402                         md_write_end(conf->mddev);
3403                         bio_io_error(bi);
3404                         bi = bi2;
3405                 }
3406
3407                 /* fail any reads if this device is non-operational and
3408                  * the data has not reached the cache yet.
3409                  */
3410                 if (!test_bit(R5_Wantfill, &sh->dev[i].flags) &&
3411                     s->failed > conf->max_degraded &&
3412                     (!test_bit(R5_Insync, &sh->dev[i].flags) ||
3413                       test_bit(R5_ReadError, &sh->dev[i].flags))) {
3414                         spin_lock_irq(&sh->stripe_lock);
3415                         bi = sh->dev[i].toread;
3416                         sh->dev[i].toread = NULL;
3417                         spin_unlock_irq(&sh->stripe_lock);
3418                         if (test_and_clear_bit(R5_Overlap, &sh->dev[i].flags))
3419                                 wake_up(&conf->wait_for_overlap);
3420                         if (bi)
3421                                 s->to_read--;
3422                         while (bi && bi->bi_iter.bi_sector <
3423                                sh->dev[i].sector + STRIPE_SECTORS) {
3424                                 struct bio *nextbi =
3425                                         r5_next_bio(bi, sh->dev[i].sector);
3426
3427                                 bio_io_error(bi);
3428                                 bi = nextbi;
3429                         }
3430                 }
3431                 if (bitmap_end)
3432                         bitmap_endwrite(conf->mddev->bitmap, sh->sector,
3433                                         STRIPE_SECTORS, 0, 0);
3434                 /* If we were in the middle of a write the parity block might
3435                  * still be locked - so just clear all R5_LOCKED flags
3436                  */
3437                 clear_bit(R5_LOCKED, &sh->dev[i].flags);
3438         }
3439         s->to_write = 0;
3440         s->written = 0;
3441
3442         if (test_and_clear_bit(STRIPE_FULL_WRITE, &sh->state))
3443                 if (atomic_dec_and_test(&conf->pending_full_writes))
3444                         md_wakeup_thread(conf->mddev->thread);
3445 }
3446
3447 static void
3448 handle_failed_sync(struct r5conf *conf, struct stripe_head *sh,
3449                    struct stripe_head_state *s)
3450 {
3451         int abort = 0;
3452         int i;
3453
3454         BUG_ON(sh->batch_head);
3455         clear_bit(STRIPE_SYNCING, &sh->state);
3456         if (test_and_clear_bit(R5_Overlap, &sh->dev[sh->pd_idx].flags))
3457                 wake_up(&conf->wait_for_overlap);
3458         s->syncing = 0;
3459         s->replacing = 0;
3460         /* There is nothing more to do for sync/check/repair.
3461          * Don't even need to abort as that is handled elsewhere
3462          * if needed, and not always wanted e.g. if there is a known
3463          * bad block here.
3464          * For recover/replace we need to record a bad block on all
3465          * non-sync devices, or abort the recovery
3466          */
3467         if (test_bit(MD_RECOVERY_RECOVER, &conf->mddev->recovery)) {
3468                 /* During recovery devices cannot be removed, so
3469                  * locking and refcounting of rdevs is not needed
3470                  */
3471                 rcu_read_lock();
3472                 for (i = 0; i < conf->raid_disks; i++) {
3473                         struct md_rdev *rdev = rcu_dereference(conf->disks[i].rdev);
3474                         if (rdev
3475                             && !test_bit(Faulty, &rdev->flags)
3476                             && !test_bit(In_sync, &rdev->flags)
3477                             && !rdev_set_badblocks(rdev, sh->sector,
3478                                                    STRIPE_SECTORS, 0))
3479                                 abort = 1;
3480                         rdev = rcu_dereference(conf->disks[i].replacement);
3481                         if (rdev
3482                             && !test_bit(Faulty, &rdev->flags)
3483                             && !test_bit(In_sync, &rdev->flags)
3484                             && !rdev_set_badblocks(rdev, sh->sector,
3485                                                    STRIPE_SECTORS, 0))
3486                                 abort = 1;
3487                 }
3488                 rcu_read_unlock();
3489                 if (abort)
3490                         conf->recovery_disabled =
3491                                 conf->mddev->recovery_disabled;
3492         }
3493         md_done_sync(conf->mddev, STRIPE_SECTORS, !abort);
3494 }
3495
3496 static int want_replace(struct stripe_head *sh, int disk_idx)
3497 {
3498         struct md_rdev *rdev;
3499         int rv = 0;
3500
3501         rcu_read_lock();
3502         rdev = rcu_dereference(sh->raid_conf->disks[disk_idx].replacement);
3503         if (rdev
3504             && !test_bit(Faulty, &rdev->flags)
3505             && !test_bit(In_sync, &rdev->flags)
3506             && (rdev->recovery_offset <= sh->sector
3507                 || rdev->mddev->recovery_cp <= sh->sector))
3508                 rv = 1;
3509         rcu_read_unlock();
3510         return rv;
3511 }
3512
3513 static int need_this_block(struct stripe_head *sh, struct stripe_head_state *s,
3514                            int disk_idx, int disks)
3515 {
3516         struct r5dev *dev = &sh->dev[disk_idx];
3517         struct r5dev *fdev[2] = { &sh->dev[s->failed_num[0]],
3518                                   &sh->dev[s->failed_num[1]] };
3519         int i;
3520
3521
3522         if (test_bit(R5_LOCKED, &dev->flags) ||
3523             test_bit(R5_UPTODATE, &dev->flags))
3524                 /* No point reading this as we already have it or have
3525                  * decided to get it.
3526                  */
3527                 return 0;
3528
3529         if (dev->toread ||
3530             (dev->towrite && !test_bit(R5_OVERWRITE, &dev->flags)))
3531                 /* We need this block to directly satisfy a request */
3532                 return 1;
3533
3534         if (s->syncing || s->expanding ||
3535             (s->replacing && want_replace(sh, disk_idx)))
3536                 /* When syncing, or expanding we read everything.
3537                  * When replacing, we need the replaced block.
3538                  */
3539                 return 1;
3540
3541         if ((s->failed >= 1 && fdev[0]->toread) ||
3542             (s->failed >= 2 && fdev[1]->toread))
3543                 /* If we want to read from a failed device, then
3544                  * we need to actually read every other device.
3545                  */
3546                 return 1;
3547
3548         /* Sometimes neither read-modify-write nor reconstruct-write
3549          * cycles can work.  In those cases we read every block we
3550          * can.  Then the parity-update is certain to have enough to
3551          * work with.
3552          * This can only be a problem when we need to write something,
3553          * and some device has failed.  If either of those tests
3554          * fail we need look no further.
3555          */
3556         if (!s->failed || !s->to_write)
3557                 return 0;
3558
3559         if (test_bit(R5_Insync, &dev->flags) &&
3560             !test_bit(STRIPE_PREREAD_ACTIVE, &sh->state))
3561                 /* Pre-reads at not permitted until after short delay
3562                  * to gather multiple requests.  However if this
3563                  * device is no Insync, the block could only be computed
3564                  * and there is no need to delay that.
3565                  */
3566                 return 0;
3567
3568         for (i = 0; i < s->failed && i < 2; i++) {
3569                 if (fdev[i]->towrite &&
3570                     !test_bit(R5_UPTODATE, &fdev[i]->flags) &&
3571                     !test_bit(R5_OVERWRITE, &fdev[i]->flags))
3572                         /* If we have a partial write to a failed
3573                          * device, then we will need to reconstruct
3574                          * the content of that device, so all other
3575                          * devices must be read.
3576                          */
3577                         return 1;
3578         }
3579
3580         /* If we are forced to do a reconstruct-write, either because
3581          * the current RAID6 implementation only supports that, or
3582          * because parity cannot be trusted and we are currently
3583          * recovering it, there is extra need to be careful.
3584          * If one of the devices that we would need to read, because
3585          * it is not being overwritten (and maybe not written at all)
3586          * is missing/faulty, then we need to read everything we can.
3587          */
3588         if (sh->raid_conf->level != 6 &&
3589             sh->sector < sh->raid_conf->mddev->recovery_cp)
3590                 /* reconstruct-write isn't being forced */
3591                 return 0;
3592         for (i = 0; i < s->failed && i < 2; i++) {
3593                 if (s->failed_num[i] != sh->pd_idx &&
3594                     s->failed_num[i] != sh->qd_idx &&
3595                     !test_bit(R5_UPTODATE, &fdev[i]->flags) &&
3596                     !test_bit(R5_OVERWRITE, &fdev[i]->flags))
3597                         return 1;
3598         }
3599
3600         return 0;
3601 }
3602
3603 /* fetch_block - checks the given member device to see if its data needs
3604  * to be read or computed to satisfy a request.
3605  *
3606  * Returns 1 when no more member devices need to be checked, otherwise returns
3607  * 0 to tell the loop in handle_stripe_fill to continue
3608  */
3609 static int fetch_block(struct stripe_head *sh, struct stripe_head_state *s,
3610                        int disk_idx, int disks)
3611 {
3612         struct r5dev *dev = &sh->dev[disk_idx];
3613
3614         /* is the data in this block needed, and can we get it? */
3615         if (need_this_block(sh, s, disk_idx, disks)) {
3616                 /* we would like to get this block, possibly by computing it,
3617                  * otherwise read it if the backing disk is insync
3618                  */
3619                 BUG_ON(test_bit(R5_Wantcompute, &dev->flags));
3620                 BUG_ON(test_bit(R5_Wantread, &dev->flags));
3621                 BUG_ON(sh->batch_head);
3622
3623                 /*
3624                  * In the raid6 case if the only non-uptodate disk is P
3625                  * then we already trusted P to compute the other failed
3626                  * drives. It is safe to compute rather than re-read P.
3627                  * In other cases we only compute blocks from failed
3628                  * devices, otherwise check/repair might fail to detect
3629                  * a real inconsistency.
3630                  */
3631
3632                 if ((s->uptodate == disks - 1) &&
3633                     ((sh->qd_idx >= 0 && sh->pd_idx == disk_idx) ||
3634                     (s->failed && (disk_idx == s->failed_num[0] ||
3635                                    disk_idx == s->failed_num[1])))) {
3636                         /* have disk failed, and we're requested to fetch it;
3637                          * do compute it
3638                          */
3639                         pr_debug("Computing stripe %llu block %d\n",
3640                                (unsigned long long)sh->sector, disk_idx);
3641                         set_bit(STRIPE_COMPUTE_RUN, &sh->state);
3642                         set_bit(STRIPE_OP_COMPUTE_BLK, &s->ops_request);
3643                         set_bit(R5_Wantcompute, &dev->flags);
3644                         sh->ops.target = disk_idx;
3645                         sh->ops.target2 = -1; /* no 2nd target */
3646                         s->req_compute = 1;
3647                         /* Careful: from this point on 'uptodate' is in the eye
3648                          * of raid_run_ops which services 'compute' operations
3649                          * before writes. R5_Wantcompute flags a block that will
3650                          * be R5_UPTODATE by the time it is needed for a
3651                          * subsequent operation.
3652                          */
3653                         s->uptodate++;
3654                         return 1;
3655                 } else if (s->uptodate == disks-2 && s->failed >= 2) {
3656                         /* Computing 2-failure is *very* expensive; only
3657                          * do it if failed >= 2
3658                          */
3659                         int other;
3660                         for (other = disks; other--; ) {
3661                                 if (other == disk_idx)
3662                                         continue;
3663                                 if (!test_bit(R5_UPTODATE,
3664                                       &sh->dev[other].flags))
3665                                         break;
3666                         }
3667                         BUG_ON(other < 0);
3668                         pr_debug("Computing stripe %llu blocks %d,%d\n",
3669                                (unsigned long long)sh->sector,
3670                                disk_idx, other);
3671                         set_bit(STRIPE_COMPUTE_RUN, &sh->state);
3672                         set_bit(STRIPE_OP_COMPUTE_BLK, &s->ops_request);
3673                         set_bit(R5_Wantcompute, &sh->dev[disk_idx].flags);
3674                         set_bit(R5_Wantcompute, &sh->dev[other].flags);
3675                         sh->ops.target = disk_idx;
3676                         sh->ops.target2 = other;
3677                         s->uptodate += 2;
3678                         s->req_compute = 1;
3679                         return 1;
3680                 } else if (test_bit(R5_Insync, &dev->flags)) {
3681                         set_bit(R5_LOCKED, &dev->flags);
3682                         set_bit(R5_Wantread, &dev->flags);
3683                         s->locked++;
3684                         pr_debug("Reading block %d (sync=%d)\n",
3685                                 disk_idx, s->syncing);
3686                 }
3687         }
3688
3689         return 0;
3690 }
3691
3692 /**
3693  * handle_stripe_fill - read or compute data to satisfy pending requests.
3694  */
3695 static void handle_stripe_fill(struct stripe_head *sh,
3696                                struct stripe_head_state *s,
3697                                int disks)
3698 {
3699         int i;
3700
3701         /* look for blocks to read/compute, skip this if a compute
3702          * is already in flight, or if the stripe contents are in the
3703          * midst of changing due to a write
3704          */
3705         if (!test_bit(STRIPE_COMPUTE_RUN, &sh->state) && !sh->check_state &&
3706             !sh->reconstruct_state) {
3707
3708                 /*
3709                  * For degraded stripe with data in journal, do not handle
3710                  * read requests yet, instead, flush the stripe to raid
3711                  * disks first, this avoids handling complex rmw of write
3712                  * back cache (prexor with orig_page, and then xor with
3713                  * page) in the read path
3714                  */
3715                 if (s->injournal && s->failed) {
3716                         if (test_bit(STRIPE_R5C_CACHING, &sh->state))
3717                                 r5c_make_stripe_write_out(sh);
3718                         goto out;
3719                 }
3720
3721                 for (i = disks; i--; )
3722                         if (fetch_block(sh, s, i, disks))
3723                                 break;
3724         }
3725 out:
3726         set_bit(STRIPE_HANDLE, &sh->state);
3727 }
3728
3729 static void break_stripe_batch_list(struct stripe_head *head_sh,
3730                                     unsigned long handle_flags);
3731 /* handle_stripe_clean_event
3732  * any written block on an uptodate or failed drive can be returned.
3733  * Note that if we 'wrote' to a failed drive, it will be UPTODATE, but
3734  * never LOCKED, so we don't need to test 'failed' directly.
3735  */
3736 static void handle_stripe_clean_event(struct r5conf *conf,
3737         struct stripe_head *sh, int disks)
3738 {
3739         int i;
3740         struct r5dev *dev;
3741         int discard_pending = 0;
3742         struct stripe_head *head_sh = sh;
3743         bool do_endio = false;
3744
3745         for (i = disks; i--; )
3746                 if (sh->dev[i].written) {
3747                         dev = &sh->dev[i];
3748                         if (!test_bit(R5_LOCKED, &dev->flags) &&
3749                             (test_bit(R5_UPTODATE, &dev->flags) ||
3750                              test_bit(R5_Discard, &dev->flags) ||
3751                              test_bit(R5_SkipCopy, &dev->flags))) {
3752                                 /* We can return any write requests */
3753                                 struct bio *wbi, *wbi2;
3754                                 pr_debug("Return write for disc %d\n", i);
3755                                 if (test_and_clear_bit(R5_Discard, &dev->flags))
3756                                         clear_bit(R5_UPTODATE, &dev->flags);
3757                                 if (test_and_clear_bit(R5_SkipCopy, &dev->flags)) {
3758                                         WARN_ON(test_bit(R5_UPTODATE, &dev->flags));
3759                                 }
3760                                 do_endio = true;
3761
3762 returnbi:
3763                                 dev->page = dev->orig_page;
3764                                 wbi = dev->written;
3765                                 dev->written = NULL;
3766                                 while (wbi && wbi->bi_iter.bi_sector <
3767                                         dev->sector + STRIPE_SECTORS) {
3768                                         wbi2 = r5_next_bio(wbi, dev->sector);
3769                                         md_write_end(conf->mddev);
3770                                         bio_endio(wbi);
3771                                         wbi = wbi2;
3772                                 }
3773                                 bitmap_endwrite(conf->mddev->bitmap, sh->sector,
3774                                                 STRIPE_SECTORS,
3775                                          !test_bit(STRIPE_DEGRADED, &sh->state),
3776                                                 0);
3777                                 if (head_sh->batch_head) {
3778                                         sh = list_first_entry(&sh->batch_list,
3779                                                               struct stripe_head,
3780                                                               batch_list);
3781                                         if (sh != head_sh) {
3782                                                 dev = &sh->dev[i];
3783                                                 goto returnbi;
3784                                         }
3785                                 }
3786                                 sh = head_sh;
3787                                 dev = &sh->dev[i];
3788                         } else if (test_bit(R5_Discard, &dev->flags))
3789                                 discard_pending = 1;
3790                 }
3791
3792         log_stripe_write_finished(sh);
3793
3794         if (!discard_pending &&
3795             test_bit(R5_Discard, &sh->dev[sh->pd_idx].flags)) {
3796                 int hash;
3797                 clear_bit(R5_Discard, &sh->dev[sh->pd_idx].flags);
3798                 clear_bit(R5_UPTODATE, &sh->dev[sh->pd_idx].flags);
3799                 if (sh->qd_idx >= 0) {
3800                         clear_bit(R5_Discard, &sh->dev[sh->qd_idx].flags);
3801                         clear_bit(R5_UPTODATE, &sh->dev[sh->qd_idx].flags);
3802                 }
3803                 /* now that discard is done we can proceed with any sync */
3804                 clear_bit(STRIPE_DISCARD, &sh->state);
3805                 /*
3806                  * SCSI discard will change some bio fields and the stripe has
3807                  * no updated data, so remove it from hash list and the stripe
3808                  * will be reinitialized
3809                  */
3810 unhash:
3811                 hash = sh->hash_lock_index;
3812                 spin_lock_irq(conf->hash_locks + hash);
3813                 remove_hash(sh);
3814                 spin_unlock_irq(conf->hash_locks + hash);
3815                 if (head_sh->batch_head) {
3816                         sh = list_first_entry(&sh->batch_list,
3817                                               struct stripe_head, batch_list);
3818                         if (sh != head_sh)
3819                                         goto unhash;
3820                 }
3821                 sh = head_sh;
3822
3823                 if (test_bit(STRIPE_SYNC_REQUESTED, &sh->state))
3824                         set_bit(STRIPE_HANDLE, &sh->state);
3825
3826         }
3827
3828         if (test_and_clear_bit(STRIPE_FULL_WRITE, &sh->state))
3829                 if (atomic_dec_and_test(&conf->pending_full_writes))
3830                         md_wakeup_thread(conf->mddev->thread);
3831
3832         if (head_sh->batch_head && do_endio)
3833                 break_stripe_batch_list(head_sh, STRIPE_EXPAND_SYNC_FLAGS);
3834 }
3835
3836 /*
3837  * For RMW in write back cache, we need extra page in prexor to store the
3838  * old data. This page is stored in dev->orig_page.
3839  *
3840  * This function checks whether we have data for prexor. The exact logic
3841  * is:
3842  *       R5_UPTODATE && (!R5_InJournal || R5_OrigPageUPTDODATE)
3843  */
3844 static inline bool uptodate_for_rmw(struct r5dev *dev)
3845 {
3846         return (test_bit(R5_UPTODATE, &dev->flags)) &&
3847                 (!test_bit(R5_InJournal, &dev->flags) ||
3848                  test_bit(R5_OrigPageUPTDODATE, &dev->flags));
3849 }
3850
3851 static int handle_stripe_dirtying(struct r5conf *conf,
3852                                   struct stripe_head *sh,
3853                                   struct stripe_head_state *s,
3854                                   int disks)
3855 {
3856         int rmw = 0, rcw = 0, i;
3857         sector_t recovery_cp = conf->mddev->recovery_cp;
3858
3859         /* Check whether resync is now happening or should start.
3860          * If yes, then the array is dirty (after unclean shutdown or
3861          * initial creation), so parity in some stripes might be inconsistent.
3862          * In this case, we need to always do reconstruct-write, to ensure
3863          * that in case of drive failure or read-error correction, we
3864          * generate correct data from the parity.
3865          */
3866         if (conf->rmw_level == PARITY_DISABLE_RMW ||
3867             (recovery_cp < MaxSector && sh->sector >= recovery_cp &&
3868              s->failed == 0)) {
3869                 /* Calculate the real rcw later - for now make it
3870                  * look like rcw is cheaper
3871                  */
3872                 rcw = 1; rmw = 2;
3873                 pr_debug("force RCW rmw_level=%u, recovery_cp=%llu sh->sector=%llu\n",
3874                          conf->rmw_level, (unsigned long long)recovery_cp,
3875                          (unsigned long long)sh->sector);
3876         } else for (i = disks; i--; ) {
3877                 /* would I have to read this buffer for read_modify_write */
3878                 struct r5dev *dev = &sh->dev[i];
3879                 if (((dev->towrite && !delay_towrite(conf, dev, s)) ||
3880                      i == sh->pd_idx || i == sh->qd_idx ||
3881                      test_bit(R5_InJournal, &dev->flags)) &&
3882                     !test_bit(R5_LOCKED, &dev->flags) &&
3883                     !(uptodate_for_rmw(dev) ||
3884                       test_bit(R5_Wantcompute, &dev->flags))) {
3885                         if (test_bit(R5_Insync, &dev->flags))
3886                                 rmw++;
3887                         else
3888                                 rmw += 2*disks;  /* cannot read it */
3889                 }
3890                 /* Would I have to read this buffer for reconstruct_write */
3891                 if (!test_bit(R5_OVERWRITE, &dev->flags) &&
3892                     i != sh->pd_idx && i != sh->qd_idx &&
3893                     !test_bit(R5_LOCKED, &dev->flags) &&
3894                     !(test_bit(R5_UPTODATE, &dev->flags) ||
3895                       test_bit(R5_Wantcompute, &dev->flags))) {
3896                         if (test_bit(R5_Insync, &dev->flags))
3897                                 rcw++;
3898                         else
3899                                 rcw += 2*disks;
3900                 }
3901         }
3902
3903         pr_debug("for sector %llu state 0x%lx, rmw=%d rcw=%d\n",
3904                  (unsigned long long)sh->sector, sh->state, rmw, rcw);
3905         set_bit(STRIPE_HANDLE, &sh->state);
3906         if ((rmw < rcw || (rmw == rcw && conf->rmw_level == PARITY_PREFER_RMW)) && rmw > 0) {
3907                 /* prefer read-modify-write, but need to get some data */
3908                 if (conf->mddev->queue)
3909                         blk_add_trace_msg(conf->mddev->queue,
3910                                           "raid5 rmw %llu %d",
3911                                           (unsigned long long)sh->sector, rmw);
3912                 for (i = disks; i--; ) {
3913                         struct r5dev *dev = &sh->dev[i];
3914                         if (test_bit(R5_InJournal, &dev->flags) &&
3915                             dev->page == dev->orig_page &&
3916                             !test_bit(R5_LOCKED, &sh->dev[sh->pd_idx].flags)) {
3917                                 /* alloc page for prexor */
3918                                 struct page *p = alloc_page(GFP_NOIO);
3919
3920                                 if (p) {
3921                                         dev->orig_page = p;
3922                                         continue;
3923                                 }
3924
3925                                 /*
3926                                  * alloc_page() failed, try use
3927                                  * disk_info->extra_page
3928                                  */
3929                                 if (!test_and_set_bit(R5C_EXTRA_PAGE_IN_USE,
3930                                                       &conf->cache_state)) {
3931                                         r5c_use_extra_page(sh);
3932                                         break;
3933                                 }
3934
3935                                 /* extra_page in use, add to delayed_list */
3936                                 set_bit(STRIPE_DELAYED, &sh->state);
3937                                 s->waiting_extra_page = 1;
3938                                 return -EAGAIN;
3939                         }
3940                 }
3941
3942                 for (i = disks; i--; ) {
3943                         struct r5dev *dev = &sh->dev[i];
3944                         if (((dev->towrite && !delay_towrite(conf, dev, s)) ||
3945                              i == sh->pd_idx || i == sh->qd_idx ||
3946                              test_bit(R5_InJournal, &dev->flags)) &&
3947                             !test_bit(R5_LOCKED, &dev->flags) &&
3948                             !(uptodate_for_rmw(dev) ||
3949                               test_bit(R5_Wantcompute, &dev->flags)) &&
3950                             test_bit(R5_Insync, &dev->flags)) {
3951                                 if (test_bit(STRIPE_PREREAD_ACTIVE,
3952                                              &sh->state)) {
3953                                         pr_debug("Read_old block %d for r-m-w\n",
3954                                                  i);
3955                                         set_bit(R5_LOCKED, &dev->flags);
3956                                         set_bit(R5_Wantread, &dev->flags);
3957                                         s->locked++;
3958                                 } else {
3959                                         set_bit(STRIPE_DELAYED, &sh->state);
3960                                         set_bit(STRIPE_HANDLE, &sh->state);
3961                                 }
3962                         }
3963                 }
3964         }
3965         if ((rcw < rmw || (rcw == rmw && conf->rmw_level != PARITY_PREFER_RMW)) && rcw > 0) {
3966                 /* want reconstruct write, but need to get some data */
3967                 int qread =0;
3968                 rcw = 0;
3969                 for (i = disks; i--; ) {
3970                         struct r5dev *dev = &sh->dev[i];
3971                         if (!test_bit(R5_OVERWRITE, &dev->flags) &&
3972                             i != sh->pd_idx && i != sh->qd_idx &&
3973                             !test_bit(R5_LOCKED, &dev->flags) &&
3974                             !(test_bit(R5_UPTODATE, &dev->flags) ||
3975                               test_bit(R5_Wantcompute, &dev->flags))) {
3976                                 rcw++;
3977                                 if (test_bit(R5_Insync, &dev->flags) &&
3978                                     test_bit(STRIPE_PREREAD_ACTIVE,
3979                                              &sh->state)) {
3980                                         pr_debug("Read_old block "
3981                                                 "%d for Reconstruct\n", i);
3982                                         set_bit(R5_LOCKED, &dev->flags);
3983                                         set_bit(R5_Wantread, &dev->flags);
3984                                         s->locked++;
3985                                         qread++;
3986                                 } else {
3987                                         set_bit(STRIPE_DELAYED, &sh->state);
3988                                         set_bit(STRIPE_HANDLE, &sh->state);
3989                                 }
3990                         }
3991                 }
3992                 if (rcw && conf->mddev->queue)
3993                         blk_add_trace_msg(conf->mddev->queue, "raid5 rcw %llu %d %d %d",
3994                                           (unsigned long long)sh->sector,
3995                                           rcw, qread, test_bit(STRIPE_DELAYED, &sh->state));
3996         }
3997
3998         if (rcw > disks && rmw > disks &&
3999             !test_bit(STRIPE_PREREAD_ACTIVE, &sh->state))
4000                 set_bit(STRIPE_DELAYED, &sh->state);
4001
4002         /* now if nothing is locked, and if we have enough data,
4003          * we can start a write request
4004          */
4005         /* since handle_stripe can be called at any time we need to handle the
4006          * case where a compute block operation has been submitted and then a
4007          * subsequent call wants to start a write request.  raid_run_ops only
4008          * handles the case where compute block and reconstruct are requested
4009          * simultaneously.  If this is not the case then new writes need to be
4010          * held off until the compute completes.
4011          */
4012         if ((s->req_compute || !test_bit(STRIPE_COMPUTE_RUN, &sh->state)) &&
4013             (s->locked == 0 && (rcw == 0 || rmw == 0) &&
4014              !test_bit(STRIPE_BIT_DELAY, &sh->state)))
4015                 schedule_reconstruction(sh, s, rcw == 0, 0);
4016         return 0;
4017 }
4018
4019 static void handle_parity_checks5(struct r5conf *conf, struct stripe_head *sh,
4020                                 struct stripe_head_state *s, int disks)
4021 {
4022         struct r5dev *dev = NULL;
4023
4024         BUG_ON(sh->batch_head);
4025         set_bit(STRIPE_HANDLE, &sh->state);
4026
4027         switch (sh->check_state) {
4028         case check_state_idle:
4029                 /* start a new check operation if there are no failures */
4030                 if (s->failed == 0) {
4031                         BUG_ON(s->uptodate != disks);
4032                         sh->check_state = check_state_run;
4033                         set_bit(STRIPE_OP_CHECK, &s->ops_request);
4034                         clear_bit(R5_UPTODATE, &sh->dev[sh->pd_idx].flags);
4035                         s->uptodate--;
4036                         break;
4037                 }
4038                 dev = &sh->dev[s->failed_num[0]];
4039                 /* fall through */
4040         case check_state_compute_result:
4041                 sh->check_state = check_state_idle;
4042                 if (!dev)
4043                         dev = &sh->dev[sh->pd_idx];
4044
4045                 /* check that a write has not made the stripe insync */
4046                 if (test_bit(STRIPE_INSYNC, &sh->state))
4047                         break;
4048
4049                 /* either failed parity check, or recovery is happening */
4050                 BUG_ON(!test_bit(R5_UPTODATE, &dev->flags));
4051                 BUG_ON(s->uptodate != disks);
4052
4053                 set_bit(R5_LOCKED, &dev->flags);
4054                 s->locked++;
4055                 set_bit(R5_Wantwrite, &dev->flags);
4056
4057                 clear_bit(STRIPE_DEGRADED, &sh->state);
4058                 set_bit(STRIPE_INSYNC, &sh->state);
4059                 break;
4060         case check_state_run:
4061                 break; /* we will be called again upon completion */
4062         case check_state_check_result:
4063                 sh->check_state = check_state_idle;
4064
4065                 /* if a failure occurred during the check operation, leave
4066                  * STRIPE_INSYNC not set and let the stripe be handled again
4067                  */
4068                 if (s->failed)
4069                         break;
4070
4071                 /* handle a successful check operation, if parity is correct
4072                  * we are done.  Otherwise update the mismatch count and repair
4073                  * parity if !MD_RECOVERY_CHECK
4074                  */
4075                 if ((sh->ops.zero_sum_result & SUM_CHECK_P_RESULT) == 0)
4076                         /* parity is correct (on disc,
4077                          * not in buffer any more)
4078                          */
4079                         set_bit(STRIPE_INSYNC, &sh->state);
4080                 else {
4081                         atomic64_add(STRIPE_SECTORS, &conf->mddev->resync_mismatches);
4082                         if (test_bit(MD_RECOVERY_CHECK, &conf->mddev->recovery)) {
4083                                 /* don't try to repair!! */
4084                                 set_bit(STRIPE_INSYNC, &sh->state);
4085                                 pr_warn_ratelimited("%s: mismatch sector in range "
4086                                                     "%llu-%llu\n", mdname(conf->mddev),
4087                                                     (unsigned long long) sh->sector,
4088                                                     (unsigned long long) sh->sector +
4089                                                     STRIPE_SECTORS);
4090                         } else {
4091                                 sh->check_state = check_state_compute_run;
4092                                 set_bit(STRIPE_COMPUTE_RUN, &sh->state);
4093                                 set_bit(STRIPE_OP_COMPUTE_BLK, &s->ops_request);
4094                                 set_bit(R5_Wantcompute,
4095                                         &sh->dev[sh->pd_idx].flags);
4096                                 sh->ops.target = sh->pd_idx;
4097                                 sh->ops.target2 = -1;
4098                                 s->uptodate++;
4099                         }
4100                 }
4101                 break;
4102         case check_state_compute_run:
4103                 break;
4104         default:
4105                 pr_err("%s: unknown check_state: %d sector: %llu\n",
4106                        __func__, sh->check_state,
4107                        (unsigned long long) sh->sector);
4108                 BUG();
4109         }
4110 }
4111
4112 static void handle_parity_checks6(struct r5conf *conf, struct stripe_head *sh,
4113                                   struct stripe_head_state *s,
4114                                   int disks)
4115 {
4116         int pd_idx = sh->pd_idx;
4117         int qd_idx = sh->qd_idx;
4118         struct r5dev *dev;
4119
4120         BUG_ON(sh->batch_head);
4121         set_bit(STRIPE_HANDLE, &sh->state);
4122
4123         BUG_ON(s->failed > 2);
4124
4125         /* Want to check and possibly repair P and Q.
4126          * However there could be one 'failed' device, in which
4127          * case we can only check one of them, possibly using the
4128          * other to generate missing data
4129          */
4130
4131         switch (sh->check_state) {
4132         case check_state_idle:
4133                 /* start a new check operation if there are < 2 failures */
4134                 if (s->failed == s->q_failed) {
4135                         /* The only possible failed device holds Q, so it
4136                          * makes sense to check P (If anything else were failed,
4137                          * we would have used P to recreate it).
4138                          */
4139                         sh->check_state = check_state_run;
4140                 }
4141                 if (!s->q_failed && s->failed < 2) {
4142                         /* Q is not failed, and we didn't use it to generate
4143                          * anything, so it makes sense to check it
4144                          */
4145                         if (sh->check_state == check_state_run)
4146                                 sh->check_state = check_state_run_pq;
4147                         else
4148                                 sh->check_state = check_state_run_q;
4149                 }
4150
4151                 /* discard potentially stale zero_sum_result */
4152                 sh->ops.zero_sum_result = 0;
4153
4154                 if (sh->check_state == check_state_run) {
4155                         /* async_xor_zero_sum destroys the contents of P */
4156                         clear_bit(R5_UPTODATE, &sh->dev[pd_idx].flags);
4157                         s->uptodate--;
4158                 }
4159                 if (sh->check_state >= check_state_run &&
4160                     sh->check_state <= check_state_run_pq) {
4161                         /* async_syndrome_zero_sum preserves P and Q, so
4162                          * no need to mark them !uptodate here
4163                          */
4164                         set_bit(STRIPE_OP_CHECK, &s->ops_request);
4165                         break;
4166                 }
4167
4168                 /* we have 2-disk failure */
4169                 BUG_ON(s->failed != 2);
4170                 /* fall through */
4171         case check_state_compute_result:
4172                 sh->check_state = check_state_idle;
4173
4174                 /* check that a write has not made the stripe insync */
4175                 if (test_bit(STRIPE_INSYNC, &sh->state))
4176                         break;
4177
4178                 /* now write out any block on a failed drive,
4179                  * or P or Q if they were recomputed
4180                  */
4181                 BUG_ON(s->uptodate < disks - 1); /* We don't need Q to recover */
4182                 if (s->failed == 2) {
4183                         dev = &sh->dev[s->failed_num[1]];
4184                         s->locked++;
4185                         set_bit(R5_LOCKED, &dev->flags);
4186                         set_bit(R5_Wantwrite, &dev->flags);
4187                 }
4188                 if (s->failed >= 1) {
4189                         dev = &sh->dev[s->failed_num[0]];
4190                         s->locked++;
4191                         set_bit(R5_LOCKED, &dev->flags);
4192                         set_bit(R5_Wantwrite, &dev->flags);
4193                 }
4194                 if (sh->ops.zero_sum_result & SUM_CHECK_P_RESULT) {
4195                         dev = &sh->dev[pd_idx];
4196                         s->locked++;
4197                         set_bit(R5_LOCKED, &dev->flags);
4198                         set_bit(R5_Wantwrite, &dev->flags);
4199                 }
4200                 if (sh->ops.zero_sum_result & SUM_CHECK_Q_RESULT) {
4201                         dev = &sh->dev[qd_idx];
4202                         s->locked++;
4203                         set_bit(R5_LOCKED, &dev->flags);
4204                         set_bit(R5_Wantwrite, &dev->flags);
4205                 }
4206                 clear_bit(STRIPE_DEGRADED, &sh->state);
4207
4208                 set_bit(STRIPE_INSYNC, &sh->state);
4209                 break;
4210         case check_state_run:
4211         case check_state_run_q:
4212         case check_state_run_pq:
4213                 break; /* we will be called again upon completion */
4214         case check_state_check_result:
4215                 sh->check_state = check_state_idle;
4216
4217                 /* handle a successful check operation, if parity is correct
4218                  * we are done.  Otherwise update the mismatch count and repair
4219                  * parity if !MD_RECOVERY_CHECK
4220                  */
4221                 if (sh->ops.zero_sum_result == 0) {
4222                         /* both parities are correct */
4223                         if (!s->failed)
4224                                 set_bit(STRIPE_INSYNC, &sh->state);
4225                         else {
4226                                 /* in contrast to the raid5 case we can validate
4227                                  * parity, but still have a failure to write
4228                                  * back
4229                                  */
4230                                 sh->check_state = check_state_compute_result;
4231                                 /* Returning at this point means that we may go
4232                                  * off and bring p and/or q uptodate again so
4233                                  * we make sure to check zero_sum_result again
4234                                  * to verify if p or q need writeback
4235                                  */
4236                         }
4237                 } else {
4238                         atomic64_add(STRIPE_SECTORS, &conf->mddev->resync_mismatches);
4239                         if (test_bit(MD_RECOVERY_CHECK, &conf->mddev->recovery)) {
4240                                 /* don't try to repair!! */
4241                                 set_bit(STRIPE_INSYNC, &sh->state);
4242                                 pr_warn_ratelimited("%s: mismatch sector in range "
4243                                                     "%llu-%llu\n", mdname(conf->mddev),
4244                                                     (unsigned long long) sh->sector,
4245                                                     (unsigned long long) sh->sector +
4246                                                     STRIPE_SECTORS);
4247                         } else {
4248                                 int *target = &sh->ops.target;
4249
4250                                 sh->ops.target = -1;
4251                                 sh->ops.target2 = -1;
4252                                 sh->check_state = check_state_compute_run;
4253                                 set_bit(STRIPE_COMPUTE_RUN, &sh->state);
4254                                 set_bit(STRIPE_OP_COMPUTE_BLK, &s->ops_request);
4255                                 if (sh->ops.zero_sum_result & SUM_CHECK_P_RESULT) {
4256                                         set_bit(R5_Wantcompute,
4257                                                 &sh->dev[pd_idx].flags);
4258                                         *target = pd_idx;
4259                                         target = &sh->ops.target2;
4260                                         s->uptodate++;
4261                                 }
4262                                 if (sh->ops.zero_sum_result & SUM_CHECK_Q_RESULT) {
4263                                         set_bit(R5_Wantcompute,
4264                                                 &sh->dev[qd_idx].flags);
4265                                         *target = qd_idx;
4266                                         s->uptodate++;
4267                                 }
4268                         }
4269                 }
4270                 break;
4271         case check_state_compute_run:
4272                 break;
4273         default:
4274                 pr_warn("%s: unknown check_state: %d sector: %llu\n",
4275                         __func__, sh->check_state,
4276                         (unsigned long long) sh->sector);
4277                 BUG();
4278         }
4279 }
4280
4281 static void handle_stripe_expansion(struct r5conf *conf, struct stripe_head *sh)
4282 {
4283         int i;
4284
4285         /* We have read all the blocks in this stripe and now we need to
4286          * copy some of them into a target stripe for expand.
4287          */
4288         struct dma_async_tx_descriptor *tx = NULL;
4289         BUG_ON(sh->batch_head);
4290         clear_bit(STRIPE_EXPAND_SOURCE, &sh->state);
4291         for (i = 0; i < sh->disks; i++)
4292                 if (i != sh->pd_idx && i != sh->qd_idx) {
4293                         int dd_idx, j;
4294                         struct stripe_head *sh2;
4295                         struct async_submit_ctl submit;
4296
4297                         sector_t bn = raid5_compute_blocknr(sh, i, 1);
4298                         sector_t s = raid5_compute_sector(conf, bn, 0,
4299                                                           &dd_idx, NULL);
4300                         sh2 = raid5_get_active_stripe(conf, s, 0, 1, 1);
4301                         if (sh2 == NULL)
4302                                 /* so far only the early blocks of this stripe
4303                                  * have been requested.  When later blocks
4304                                  * get requested, we will try again
4305                                  */
4306                                 continue;
4307                         if (!test_bit(STRIPE_EXPANDING, &sh2->state) ||
4308                            test_bit(R5_Expanded, &sh2->dev[dd_idx].flags)) {
4309                                 /* must have already done this block */
4310                                 raid5_release_stripe(sh2);
4311                                 continue;
4312                         }
4313
4314                         /* place all the copies on one channel */
4315                         init_async_submit(&submit, 0, tx, NULL, NULL, NULL);
4316                         tx = async_memcpy(sh2->dev[dd_idx].page,
4317                                           sh->dev[i].page, 0, 0, STRIPE_SIZE,
4318                                           &submit);
4319
4320                         set_bit(R5_Expanded, &sh2->dev[dd_idx].flags);
4321                         set_bit(R5_UPTODATE, &sh2->dev[dd_idx].flags);
4322                         for (j = 0; j < conf->raid_disks; j++)
4323                                 if (j != sh2->pd_idx &&
4324                                     j != sh2->qd_idx &&
4325                                     !test_bit(R5_Expanded, &sh2->dev[j].flags))
4326                                         break;
4327                         if (j == conf->raid_disks) {
4328                                 set_bit(STRIPE_EXPAND_READY, &sh2->state);
4329                                 set_bit(STRIPE_HANDLE, &sh2->state);
4330                         }
4331                         raid5_release_stripe(sh2);
4332
4333                 }
4334         /* done submitting copies, wait for them to complete */
4335         async_tx_quiesce(&tx);
4336 }
4337
4338 /*
4339  * handle_stripe - do things to a stripe.
4340  *
4341  * We lock the stripe by setting STRIPE_ACTIVE and then examine the
4342  * state of various bits to see what needs to be done.
4343  * Possible results:
4344  *    return some read requests which now have data
4345  *    return some write requests which are safely on storage
4346  *    schedule a read on some buffers
4347  *    schedule a write of some buffers
4348  *    return confirmation of parity correctness
4349  *
4350  */
4351
4352 static void analyse_stripe(struct stripe_head *sh, struct stripe_head_state *s)
4353 {
4354         struct r5conf *conf = sh->raid_conf;
4355         int disks = sh->disks;
4356         struct r5dev *dev;
4357         int i;
4358         int do_recovery = 0;
4359
4360         memset(s, 0, sizeof(*s));
4361
4362         s->expanding = test_bit(STRIPE_EXPAND_SOURCE, &sh->state) && !sh->batch_head;
4363         s->expanded = test_bit(STRIPE_EXPAND_READY, &sh->state) && !sh->batch_head;
4364         s->failed_num[0] = -1;
4365         s->failed_num[1] = -1;
4366         s->log_failed = r5l_log_disk_error(conf);
4367
4368         /* Now to look around and see what can be done */
4369         rcu_read_lock();
4370         for (i=disks; i--; ) {
4371                 struct md_rdev *rdev;
4372                 sector_t first_bad;
4373                 int bad_sectors;
4374                 int is_bad = 0;
4375
4376                 dev = &sh->dev[i];
4377
4378                 pr_debug("check %d: state 0x%lx read %p write %p written %p\n",
4379                          i, dev->flags,
4380                          dev->toread, dev->towrite, dev->written);
4381                 /* maybe we can reply to a read
4382                  *
4383                  * new wantfill requests are only permitted while
4384                  * ops_complete_biofill is guaranteed to be inactive
4385                  */
4386                 if (test_bit(R5_UPTODATE, &dev->flags) && dev->toread &&
4387                     !test_bit(STRIPE_BIOFILL_RUN, &sh->state))
4388                         set_bit(R5_Wantfill, &dev->flags);
4389
4390                 /* now count some things */
4391                 if (test_bit(R5_LOCKED, &dev->flags))
4392                         s->locked++;
4393                 if (test_bit(R5_UPTODATE, &dev->flags))
4394                         s->uptodate++;
4395                 if (test_bit(R5_Wantcompute, &dev->flags)) {
4396                         s->compute++;
4397                         BUG_ON(s->compute > 2);
4398                 }
4399
4400                 if (test_bit(R5_Wantfill, &dev->flags))
4401                         s->to_fill++;
4402                 else if (dev->toread)
4403                         s->to_read++;
4404                 if (dev->towrite) {
4405                         s->to_write++;
4406                         if (!test_bit(R5_OVERWRITE, &dev->flags))
4407                                 s->non_overwrite++;
4408                 }
4409                 if (dev->written)
4410                         s->written++;
4411                 /* Prefer to use the replacement for reads, but only
4412                  * if it is recovered enough and has no bad blocks.
4413                  */
4414                 rdev = rcu_dereference(conf->disks[i].replacement);
4415                 if (rdev && !test_bit(Faulty, &rdev->flags) &&
4416                     rdev->recovery_offset >= sh->sector + STRIPE_SECTORS &&
4417                     !is_badblock(rdev, sh->sector, STRIPE_SECTORS,
4418                                  &first_bad, &bad_sectors))
4419                         set_bit(R5_ReadRepl, &dev->flags);
4420                 else {
4421                         if (rdev && !test_bit(Faulty, &rdev->flags))
4422                                 set_bit(R5_NeedReplace, &dev->flags);
4423                         else
4424                                 clear_bit(R5_NeedReplace, &dev->flags);
4425                         rdev = rcu_dereference(conf->disks[i].rdev);
4426                         clear_bit(R5_ReadRepl, &dev->flags);
4427                 }
4428                 if (rdev && test_bit(Faulty, &rdev->flags))
4429                         rdev = NULL;
4430                 if (rdev) {
4431                         is_bad = is_badblock(rdev, sh->sector, STRIPE_SECTORS,
4432                                              &first_bad, &bad_sectors);
4433                         if (s->blocked_rdev == NULL
4434                             && (test_bit(Blocked, &rdev->flags)
4435                                 || is_bad < 0)) {
4436                                 if (is_bad < 0)
4437                                         set_bit(BlockedBadBlocks,
4438                                                 &rdev->flags);
4439                                 s->blocked_rdev = rdev;
4440                                 atomic_inc(&rdev->nr_pending);
4441                         }
4442                 }
4443                 clear_bit(R5_Insync, &dev->flags);
4444                 if (!rdev)
4445                         /* Not in-sync */;
4446                 else if (is_bad) {
4447                         /* also not in-sync */
4448                         if (!test_bit(WriteErrorSeen, &rdev->flags) &&
4449                             test_bit(R5_UPTODATE, &dev->flags)) {
4450                                 /* treat as in-sync, but with a read error
4451                                  * which we can now try to correct
4452                                  */
4453                                 set_bit(R5_Insync, &dev->flags);
4454                                 set_bit(R5_ReadError, &dev->flags);
4455                         }
4456                 } else if (test_bit(In_sync, &rdev->flags))
4457                         set_bit(R5_Insync, &dev->flags);
4458                 else if (sh->sector + STRIPE_SECTORS <= rdev->recovery_offset)
4459                         /* in sync if before recovery_offset */
4460                         set_bit(R5_Insync, &dev->flags);
4461                 else if (test_bit(R5_UPTODATE, &dev->flags) &&
4462                          test_bit(R5_Expanded, &dev->flags))
4463                         /* If we've reshaped into here, we assume it is Insync.
4464                          * We will shortly update recovery_offset to make
4465                          * it official.
4466                          */
4467                         set_bit(R5_Insync, &dev->flags);
4468
4469                 if (test_bit(R5_WriteError, &dev->flags)) {
4470                         /* This flag does not apply to '.replacement'
4471                          * only to .rdev, so make sure to check that*/
4472                         struct md_rdev *rdev2 = rcu_dereference(
4473                                 conf->disks[i].rdev);
4474                         if (rdev2 == rdev)
4475                                 clear_bit(R5_Insync, &dev->flags);
4476                         if (rdev2 && !test_bit(Faulty, &rdev2->flags)) {
4477                                 s->handle_bad_blocks = 1;
4478                                 atomic_inc(&rdev2->nr_pending);
4479                         } else
4480                                 clear_bit(R5_WriteError, &dev->flags);
4481                 }
4482                 if (test_bit(R5_MadeGood, &dev->flags)) {
4483                         /* This flag does not apply to '.replacement'
4484                          * only to .rdev, so make sure to check that*/
4485                         struct md_rdev *rdev2 = rcu_dereference(
4486                                 conf->disks[i].rdev);
4487                         if (rdev2 && !test_bit(Faulty, &rdev2->flags)) {
4488                                 s->handle_bad_blocks = 1;
4489                                 atomic_inc(&rdev2->nr_pending);
4490                         } else
4491                                 clear_bit(R5_MadeGood, &dev->flags);
4492                 }
4493                 if (test_bit(R5_MadeGoodRepl, &dev->flags)) {
4494                         struct md_rdev *rdev2 = rcu_dereference(
4495                                 conf->disks[i].replacement);
4496                         if (rdev2 && !test_bit(Faulty, &rdev2->flags)) {
4497                                 s->handle_bad_blocks = 1;
4498                                 atomic_inc(&rdev2->nr_pending);
4499                         } else
4500                                 clear_bit(R5_MadeGoodRepl, &dev->flags);
4501                 }
4502                 if (!test_bit(R5_Insync, &dev->flags)) {
4503                         /* The ReadError flag will just be confusing now */
4504                         clear_bit(R5_ReadError, &dev->flags);
4505                         clear_bit(R5_ReWrite, &dev->flags);
4506                 }
4507                 if (test_bit(R5_ReadError, &dev->flags))
4508                         clear_bit(R5_Insync, &dev->flags);
4509                 if (!test_bit(R5_Insync, &dev->flags)) {
4510                         if (s->failed < 2)
4511                                 s->failed_num[s->failed] = i;
4512                         s->failed++;
4513                         if (rdev && !test_bit(Faulty, &rdev->flags))
4514                                 do_recovery = 1;
4515                 }
4516
4517                 if (test_bit(R5_InJournal, &dev->flags))
4518                         s->injournal++;
4519                 if (test_bit(R5_InJournal, &dev->flags) && dev->written)
4520                         s->just_cached++;
4521         }
4522         if (test_bit(STRIPE_SYNCING, &sh->state)) {
4523                 /* If there is a failed device being replaced,
4524                  *     we must be recovering.
4525                  * else if we are after recovery_cp, we must be syncing
4526                  * else if MD_RECOVERY_REQUESTED is set, we also are syncing.
4527                  * else we can only be replacing
4528                  * sync and recovery both need to read all devices, and so
4529                  * use the same flag.
4530                  */
4531                 if (do_recovery ||
4532                     sh->sector >= conf->mddev->recovery_cp ||
4533                     test_bit(MD_RECOVERY_REQUESTED, &(conf->mddev->recovery)))
4534                         s->syncing = 1;
4535                 else
4536                         s->replacing = 1;
4537         }
4538         rcu_read_unlock();
4539 }
4540
4541 static int clear_batch_ready(struct stripe_head *sh)
4542 {
4543         /* Return '1' if this is a member of batch, or
4544          * '0' if it is a lone stripe or a head which can now be
4545          * handled.
4546          */
4547         struct stripe_head *tmp;
4548         if (!test_and_clear_bit(STRIPE_BATCH_READY, &sh->state))
4549                 return (sh->batch_head && sh->batch_head != sh);
4550         spin_lock(&sh->stripe_lock);
4551         if (!sh->batch_head) {
4552                 spin_unlock(&sh->stripe_lock);
4553                 return 0;
4554         }
4555
4556         /*
4557          * this stripe could be added to a batch list before we check
4558          * BATCH_READY, skips it
4559          */
4560         if (sh->batch_head != sh) {
4561                 spin_unlock(&sh->stripe_lock);
4562                 return 1;
4563         }
4564         spin_lock(&sh->batch_lock);
4565         list_for_each_entry(tmp, &sh->batch_list, batch_list)
4566                 clear_bit(STRIPE_BATCH_READY, &tmp->state);
4567         spin_unlock(&sh->batch_lock);
4568         spin_unlock(&sh->stripe_lock);
4569
4570         /*
4571          * BATCH_READY is cleared, no new stripes can be added.
4572          * batch_list can be accessed without lock
4573          */
4574         return 0;
4575 }
4576
4577 static void break_stripe_batch_list(struct stripe_head *head_sh,
4578                                     unsigned long handle_flags)
4579 {
4580         struct stripe_head *sh, *next;
4581         int i;
4582         int do_wakeup = 0;
4583
4584         list_for_each_entry_safe(sh, next, &head_sh->batch_list, batch_list) {
4585
4586                 list_del_init(&sh->batch_list);
4587
4588                 WARN_ONCE(sh->state & ((1 << STRIPE_ACTIVE) |
4589                                           (1 << STRIPE_SYNCING) |
4590                                           (1 << STRIPE_REPLACED) |
4591                                           (1 << STRIPE_DELAYED) |
4592                                           (1 << STRIPE_BIT_DELAY) |
4593                                           (1 << STRIPE_FULL_WRITE) |
4594                                           (1 << STRIPE_BIOFILL_RUN) |
4595                                           (1 << STRIPE_COMPUTE_RUN)  |
4596                                           (1 << STRIPE_OPS_REQ_PENDING) |
4597                                           (1 << STRIPE_DISCARD) |
4598                                           (1 << STRIPE_BATCH_READY) |
4599                                           (1 << STRIPE_BATCH_ERR) |
4600                                           (1 << STRIPE_BITMAP_PENDING)),
4601                         "stripe state: %lx\n", sh->state);
4602                 WARN_ONCE(head_sh->state & ((1 << STRIPE_DISCARD) |
4603                                               (1 << STRIPE_REPLACED)),
4604                         "head stripe state: %lx\n", head_sh->state);
4605
4606                 set_mask_bits(&sh->state, ~(STRIPE_EXPAND_SYNC_FLAGS |
4607                                             (1 << STRIPE_PREREAD_ACTIVE) |
4608                                             (1 << STRIPE_DEGRADED) |
4609                                             (1 << STRIPE_ON_UNPLUG_LIST)),
4610                               head_sh->state & (1 << STRIPE_INSYNC));
4611
4612                 sh->check_state = head_sh->check_state;
4613                 sh->reconstruct_state = head_sh->reconstruct_state;
4614                 for (i = 0; i < sh->disks; i++) {
4615                         if (test_and_clear_bit(R5_Overlap, &sh->dev[i].flags))
4616                                 do_wakeup = 1;
4617                         sh->dev[i].flags = head_sh->dev[i].flags &
4618                                 (~((1 << R5_WriteError) | (1 << R5_Overlap)));
4619                 }
4620                 spin_lock_irq(&sh->stripe_lock);
4621                 sh->batch_head = NULL;
4622                 spin_unlock_irq(&sh->stripe_lock);
4623                 if (handle_flags == 0 ||
4624                     sh->state & handle_flags)
4625                         set_bit(STRIPE_HANDLE, &sh->state);
4626                 raid5_release_stripe(sh);
4627         }
4628         spin_lock_irq(&head_sh->stripe_lock);
4629         head_sh->batch_head = NULL;
4630         spin_unlock_irq(&head_sh->stripe_lock);
4631         for (i = 0; i < head_sh->disks; i++)
4632                 if (test_and_clear_bit(R5_Overlap, &head_sh->dev[i].flags))
4633                         do_wakeup = 1;
4634         if (head_sh->state & handle_flags)
4635                 set_bit(STRIPE_HANDLE, &head_sh->state);
4636
4637         if (do_wakeup)
4638                 wake_up(&head_sh->raid_conf->wait_for_overlap);
4639 }
4640
4641 static void handle_stripe(struct stripe_head *sh)
4642 {
4643         struct stripe_head_state s;
4644         struct r5conf *conf = sh->raid_conf;
4645         int i;
4646         int prexor;
4647         int disks = sh->disks;
4648         struct r5dev *pdev, *qdev;
4649
4650         clear_bit(STRIPE_HANDLE, &sh->state);
4651         if (test_and_set_bit_lock(STRIPE_ACTIVE, &sh->state)) {
4652                 /* already being handled, ensure it gets handled
4653                  * again when current action finishes */
4654                 set_bit(STRIPE_HANDLE, &sh->state);
4655                 return;
4656         }
4657
4658         if (clear_batch_ready(sh) ) {
4659                 clear_bit_unlock(STRIPE_ACTIVE, &sh->state);
4660                 return;
4661         }
4662
4663         if (test_and_clear_bit(STRIPE_BATCH_ERR, &sh->state))
4664                 break_stripe_batch_list(sh, 0);
4665
4666         if (test_bit(STRIPE_SYNC_REQUESTED, &sh->state) && !sh->batch_head) {
4667                 spin_lock(&sh->stripe_lock);
4668                 /*
4669                  * Cannot process 'sync' concurrently with 'discard'.
4670                  * Flush data in r5cache before 'sync'.
4671                  */
4672                 if (!test_bit(STRIPE_R5C_PARTIAL_STRIPE, &sh->state) &&
4673                     !test_bit(STRIPE_R5C_FULL_STRIPE, &sh->state) &&
4674                     !test_bit(STRIPE_DISCARD, &sh->state) &&
4675                     test_and_clear_bit(STRIPE_SYNC_REQUESTED, &sh->state)) {
4676                         set_bit(STRIPE_SYNCING, &sh->state);
4677                         clear_bit(STRIPE_INSYNC, &sh->state);
4678                         clear_bit(STRIPE_REPLACED, &sh->state);
4679                 }
4680                 spin_unlock(&sh->stripe_lock);
4681         }
4682         clear_bit(STRIPE_DELAYED, &sh->state);
4683
4684         pr_debug("handling stripe %llu, state=%#lx cnt=%d, "
4685                 "pd_idx=%d, qd_idx=%d\n, check:%d, reconstruct:%d\n",
4686                (unsigned long long)sh->sector, sh->state,
4687                atomic_read(&sh->count), sh->pd_idx, sh->qd_idx,
4688                sh->check_state, sh->reconstruct_state);
4689
4690         analyse_stripe(sh, &s);
4691
4692         if (test_bit(STRIPE_LOG_TRAPPED, &sh->state))
4693                 goto finish;
4694
4695         if (s.handle_bad_blocks ||
4696             test_bit(MD_SB_CHANGE_PENDING, &conf->mddev->sb_flags)) {
4697                 set_bit(STRIPE_HANDLE, &sh->state);
4698                 goto finish;
4699         }
4700
4701         if (unlikely(s.blocked_rdev)) {
4702                 if (s.syncing || s.expanding || s.expanded ||
4703                     s.replacing || s.to_write || s.written) {
4704                         set_bit(STRIPE_HANDLE, &sh->state);
4705                         goto finish;
4706                 }
4707                 /* There is nothing for the blocked_rdev to block */
4708                 rdev_dec_pending(s.blocked_rdev, conf->mddev);
4709                 s.blocked_rdev = NULL;
4710         }
4711
4712         if (s.to_fill && !test_bit(STRIPE_BIOFILL_RUN, &sh->state)) {
4713                 set_bit(STRIPE_OP_BIOFILL, &s.ops_request);
4714                 set_bit(STRIPE_BIOFILL_RUN, &sh->state);
4715         }
4716
4717         pr_debug("locked=%d uptodate=%d to_read=%d"
4718                " to_write=%d failed=%d failed_num=%d,%d\n",
4719                s.locked, s.uptodate, s.to_read, s.to_write, s.failed,
4720                s.failed_num[0], s.failed_num[1]);
4721         /*
4722          * check if the array has lost more than max_degraded devices and,
4723          * if so, some requests might need to be failed.
4724          *
4725          * When journal device failed (log_failed), we will only process
4726          * the stripe if there is data need write to raid disks
4727          */
4728         if (s.failed > conf->max_degraded ||
4729             (s.log_failed && s.injournal == 0)) {
4730                 sh->check_state = 0;
4731                 sh->reconstruct_state = 0;
4732                 break_stripe_batch_list(sh, 0);
4733                 if (s.to_read+s.to_write+s.written)
4734                         handle_failed_stripe(conf, sh, &s, disks);
4735                 if (s.syncing + s.replacing)
4736                         handle_failed_sync(conf, sh, &s);
4737         }
4738
4739         /* Now we check to see if any write operations have recently
4740          * completed
4741          */
4742         prexor = 0;
4743         if (sh->reconstruct_state == reconstruct_state_prexor_drain_result)
4744                 prexor = 1;
4745         if (sh->reconstruct_state == reconstruct_state_drain_result ||
4746             sh->reconstruct_state == reconstruct_state_prexor_drain_result) {
4747                 sh->reconstruct_state = reconstruct_state_idle;
4748
4749                 /* All the 'written' buffers and the parity block are ready to
4750                  * be written back to disk
4751                  */
4752                 BUG_ON(!test_bit(R5_UPTODATE, &sh->dev[sh->pd_idx].flags) &&
4753                        !test_bit(R5_Discard, &sh->dev[sh->pd_idx].flags));
4754                 BUG_ON(sh->qd_idx >= 0 &&
4755                        !test_bit(R5_UPTODATE, &sh->dev[sh->qd_idx].flags) &&
4756                        !test_bit(R5_Discard, &sh->dev[sh->qd_idx].flags));
4757                 for (i = disks; i--; ) {
4758                         struct r5dev *dev = &sh->dev[i];
4759                         if (test_bit(R5_LOCKED, &dev->flags) &&
4760                                 (i == sh->pd_idx || i == sh->qd_idx ||
4761                                  dev->written || test_bit(R5_InJournal,
4762                                                           &dev->flags))) {
4763                                 pr_debug("Writing block %d\n", i);
4764                                 set_bit(R5_Wantwrite, &dev->flags);
4765                                 if (prexor)
4766                                         continue;
4767                                 if (s.failed > 1)
4768                                         continue;
4769                                 if (!test_bit(R5_Insync, &dev->flags) ||
4770                                     ((i == sh->pd_idx || i == sh->qd_idx)  &&
4771                                      s.failed == 0))
4772                                         set_bit(STRIPE_INSYNC, &sh->state);
4773                         }
4774                 }
4775                 if (test_and_clear_bit(STRIPE_PREREAD_ACTIVE, &sh->state))
4776                         s.dec_preread_active = 1;
4777         }
4778
4779         /*
4780          * might be able to return some write requests if the parity blocks
4781          * are safe, or on a failed drive
4782          */
4783         pdev = &sh->dev[sh->pd_idx];
4784         s.p_failed = (s.failed >= 1 && s.failed_num[0] == sh->pd_idx)
4785                 || (s.failed >= 2 && s.failed_num[1] == sh->pd_idx);
4786         qdev = &sh->dev[sh->qd_idx];
4787         s.q_failed = (s.failed >= 1 && s.failed_num[0] == sh->qd_idx)
4788                 || (s.failed >= 2 && s.failed_num[1] == sh->qd_idx)
4789                 || conf->level < 6;
4790
4791         if (s.written &&
4792             (s.p_failed || ((test_bit(R5_Insync, &pdev->flags)
4793                              && !test_bit(R5_LOCKED, &pdev->flags)
4794                              && (test_bit(R5_UPTODATE, &pdev->flags) ||
4795                                  test_bit(R5_Discard, &pdev->flags))))) &&
4796             (s.q_failed || ((test_bit(R5_Insync, &qdev->flags)
4797                              && !test_bit(R5_LOCKED, &qdev->flags)
4798                              && (test_bit(R5_UPTODATE, &qdev->flags) ||
4799                                  test_bit(R5_Discard, &qdev->flags))))))
4800                 handle_stripe_clean_event(conf, sh, disks);
4801
4802         if (s.just_cached)
4803                 r5c_handle_cached_data_endio(conf, sh, disks);
4804         log_stripe_write_finished(sh);
4805
4806         /* Now we might consider reading some blocks, either to check/generate
4807          * parity, or to satisfy requests
4808          * or to load a block that is being partially written.
4809          */
4810         if (s.to_read || s.non_overwrite
4811             || (conf->level == 6 && s.to_write && s.failed)
4812             || (s.syncing && (s.uptodate + s.compute < disks))
4813             || s.replacing
4814             || s.expanding)
4815                 handle_stripe_fill(sh, &s, disks);
4816
4817         /*
4818          * When the stripe finishes full journal write cycle (write to journal
4819          * and raid disk), this is the clean up procedure so it is ready for
4820          * next operation.
4821          */
4822         r5c_finish_stripe_write_out(conf, sh, &s);
4823
4824         /*
4825          * Now to consider new write requests, cache write back and what else,
4826          * if anything should be read.  We do not handle new writes when:
4827          * 1/ A 'write' operation (copy+xor) is already in flight.
4828          * 2/ A 'check' operation is in flight, as it may clobber the parity
4829          *    block.
4830          * 3/ A r5c cache log write is in flight.
4831          */
4832
4833         if (!sh->reconstruct_state && !sh->check_state && !sh->log_io) {
4834                 if (!r5c_is_writeback(conf->log)) {
4835                         if (s.to_write)
4836                                 handle_stripe_dirtying(conf, sh, &s, disks);
4837                 } else { /* write back cache */
4838                         int ret = 0;
4839
4840                         /* First, try handle writes in caching phase */
4841                         if (s.to_write)
4842                                 ret = r5c_try_caching_write(conf, sh, &s,
4843                                                             disks);
4844                         /*
4845                          * If caching phase failed: ret == -EAGAIN
4846                          *    OR
4847                          * stripe under reclaim: !caching && injournal
4848                          *
4849                          * fall back to handle_stripe_dirtying()
4850                          */
4851                         if (ret == -EAGAIN ||
4852                             /* stripe under reclaim: !caching && injournal */
4853                             (!test_bit(STRIPE_R5C_CACHING, &sh->state) &&
4854                              s.injournal > 0)) {
4855                                 ret = handle_stripe_dirtying(conf, sh, &s,
4856                                                              disks);
4857                                 if (ret == -EAGAIN)
4858                                         goto finish;
4859                         }
4860                 }
4861         }
4862
4863         /* maybe we need to check and possibly fix the parity for this stripe
4864          * Any reads will already have been scheduled, so we just see if enough
4865          * data is available.  The parity check is held off while parity
4866          * dependent operations are in flight.
4867          */
4868         if (sh->check_state ||
4869             (s.syncing && s.locked == 0 &&
4870              !test_bit(STRIPE_COMPUTE_RUN, &sh->state) &&
4871              !test_bit(STRIPE_INSYNC, &sh->state))) {
4872                 if (conf->level == 6)
4873                         handle_parity_checks6(conf, sh, &s, disks);
4874                 else
4875                         handle_parity_checks5(conf, sh, &s, disks);
4876         }
4877
4878         if ((s.replacing || s.syncing) && s.locked == 0
4879             && !test_bit(STRIPE_COMPUTE_RUN, &sh->state)
4880             && !test_bit(STRIPE_REPLACED, &sh->state)) {
4881                 /* Write out to replacement devices where possible */
4882                 for (i = 0; i < conf->raid_disks; i++)
4883                         if (test_bit(R5_NeedReplace, &sh->dev[i].flags)) {
4884                                 WARN_ON(!test_bit(R5_UPTODATE, &sh->dev[i].flags));
4885                                 set_bit(R5_WantReplace, &sh->dev[i].flags);
4886                                 set_bit(R5_LOCKED, &sh->dev[i].flags);
4887                                 s.locked++;
4888                         }
4889                 if (s.replacing)
4890                         set_bit(STRIPE_INSYNC, &sh->state);
4891                 set_bit(STRIPE_REPLACED, &sh->state);
4892         }
4893         if ((s.syncing || s.replacing) && s.locked == 0 &&
4894             !test_bit(STRIPE_COMPUTE_RUN, &sh->state) &&
4895             test_bit(STRIPE_INSYNC, &sh->state)) {
4896                 md_done_sync(conf->mddev, STRIPE_SECTORS, 1);
4897                 clear_bit(STRIPE_SYNCING, &sh->state);
4898                 if (test_and_clear_bit(R5_Overlap, &sh->dev[sh->pd_idx].flags))
4899                         wake_up(&conf->wait_for_overlap);
4900         }
4901
4902         /* If the failed drives are just a ReadError, then we might need
4903          * to progress the repair/check process
4904          */
4905         if (s.failed <= conf->max_degraded && !conf->mddev->ro)
4906                 for (i = 0; i < s.failed; i++) {
4907                         struct r5dev *dev = &sh->dev[s.failed_num[i]];
4908                         if (test_bit(R5_ReadError, &dev->flags)
4909                             && !test_bit(R5_LOCKED, &dev->flags)
4910                             && test_bit(R5_UPTODATE, &dev->flags)
4911                                 ) {
4912                                 if (!test_bit(R5_ReWrite, &dev->flags)) {
4913                                         set_bit(R5_Wantwrite, &dev->flags);
4914                                         set_bit(R5_ReWrite, &dev->flags);
4915                                         set_bit(R5_LOCKED, &dev->flags);
4916                                         s.locked++;
4917                                 } else {
4918                                         /* let's read it back */
4919                                         set_bit(R5_Wantread, &dev->flags);
4920                                         set_bit(R5_LOCKED, &dev->flags);
4921                                         s.locked++;
4922                                 }
4923                         }
4924                 }
4925
4926         /* Finish reconstruct operations initiated by the expansion process */
4927         if (sh->reconstruct_state == reconstruct_state_result) {
4928                 struct stripe_head *sh_src
4929                         = raid5_get_active_stripe(conf, sh->sector, 1, 1, 1);
4930                 if (sh_src && test_bit(STRIPE_EXPAND_SOURCE, &sh_src->state)) {
4931                         /* sh cannot be written until sh_src has been read.
4932                          * so arrange for sh to be delayed a little
4933                          */
4934                         set_bit(STRIPE_DELAYED, &sh->state);
4935                         set_bit(STRIPE_HANDLE, &sh->state);
4936                         if (!test_and_set_bit(STRIPE_PREREAD_ACTIVE,
4937                                               &sh_src->state))
4938                                 atomic_inc(&conf->preread_active_stripes);
4939                         raid5_release_stripe(sh_src);
4940                         goto finish;
4941                 }
4942                 if (sh_src)
4943                         raid5_release_stripe(sh_src);
4944
4945                 sh->reconstruct_state = reconstruct_state_idle;
4946                 clear_bit(STRIPE_EXPANDING, &sh->state);
4947                 for (i = conf->raid_disks; i--; ) {
4948                         set_bit(R5_Wantwrite, &sh->dev[i].flags);
4949                         set_bit(R5_LOCKED, &sh->dev[i].flags);
4950                         s.locked++;
4951                 }
4952         }
4953
4954         if (s.expanded && test_bit(STRIPE_EXPANDING, &sh->state) &&
4955             !sh->reconstruct_state) {
4956                 /* Need to write out all blocks after computing parity */
4957                 sh->disks = conf->raid_disks;
4958                 stripe_set_idx(sh->sector, conf, 0, sh);
4959                 schedule_reconstruction(sh, &s, 1, 1);
4960         } else if (s.expanded && !sh->reconstruct_state && s.locked == 0) {
4961                 clear_bit(STRIPE_EXPAND_READY, &sh->state);
4962                 atomic_dec(&conf->reshape_stripes);
4963                 wake_up(&conf->wait_for_overlap);
4964                 md_done_sync(conf->mddev, STRIPE_SECTORS, 1);
4965         }
4966
4967         if (s.expanding && s.locked == 0 &&
4968             !test_bit(STRIPE_COMPUTE_RUN, &sh->state))
4969                 handle_stripe_expansion(conf, sh);
4970
4971 finish:
4972         /* wait for this device to become unblocked */
4973         if (unlikely(s.blocked_rdev)) {
4974                 if (conf->mddev->external)
4975                         md_wait_for_blocked_rdev(s.blocked_rdev,
4976                                                  conf->mddev);
4977                 else
4978                         /* Internal metadata will immediately
4979                          * be written by raid5d, so we don't
4980                          * need to wait here.
4981                          */
4982                         rdev_dec_pending(s.blocked_rdev,
4983                                          conf->mddev);
4984         }
4985
4986         if (s.handle_bad_blocks)
4987                 for (i = disks; i--; ) {
4988                         struct md_rdev *rdev;
4989                         struct r5dev *dev = &sh->dev[i];
4990                         if (test_and_clear_bit(R5_WriteError, &dev->flags)) {
4991                                 /* We own a safe reference to the rdev */
4992                                 rdev = conf->disks[i].rdev;
4993                                 if (!rdev_set_badblocks(rdev, sh->sector,
4994                                                         STRIPE_SECTORS, 0))
4995                                         md_error(conf->mddev, rdev);
4996                                 rdev_dec_pending(rdev, conf->mddev);
4997                         }
4998                         if (test_and_clear_bit(R5_MadeGood, &dev->flags)) {
4999                                 rdev = conf->disks[i].rdev;
5000                                 rdev_clear_badblocks(rdev, sh->sector,
5001                                                      STRIPE_SECTORS, 0);
5002                                 rdev_dec_pending(rdev, conf->mddev);
5003                         }
5004                         if (test_and_clear_bit(R5_MadeGoodRepl, &dev->flags)) {
5005                                 rdev = conf->disks[i].replacement;
5006                                 if (!rdev)
5007                                         /* rdev have been moved down */
5008                                         rdev = conf->disks[i].rdev;
5009                                 rdev_clear_badblocks(rdev, sh->sector,
5010                                                      STRIPE_SECTORS, 0);
5011                                 rdev_dec_pending(rdev, conf->mddev);
5012                         }
5013                 }
5014
5015         if (s.ops_request)
5016                 raid_run_ops(sh, s.ops_request);
5017
5018         ops_run_io(sh, &s);
5019
5020         if (s.dec_preread_active) {
5021                 /* We delay this until after ops_run_io so that if make_request
5022                  * is waiting on a flush, it won't continue until the writes
5023                  * have actually been submitted.
5024                  */
5025                 atomic_dec(&conf->preread_active_stripes);
5026                 if (atomic_read(&conf->preread_active_stripes) <
5027                     IO_THRESHOLD)
5028                         md_wakeup_thread(conf->mddev->thread);
5029         }
5030
5031         clear_bit_unlock(STRIPE_ACTIVE, &sh->state);
5032 }
5033
5034 static void raid5_activate_delayed(struct r5conf *conf)
5035 {
5036         if (atomic_read(&conf->preread_active_stripes) < IO_THRESHOLD) {
5037                 while (!list_empty(&conf->delayed_list)) {
5038                         struct list_head *l = conf->delayed_list.next;
5039                         struct stripe_head *sh;
5040                         sh = list_entry(l, struct stripe_head, lru);
5041                         list_del_init(l);
5042                         clear_bit(STRIPE_DELAYED, &sh->state);
5043                         if (!test_and_set_bit(STRIPE_PREREAD_ACTIVE, &sh->state))
5044                                 atomic_inc(&conf->preread_active_stripes);
5045                         list_add_tail(&sh->lru, &conf->hold_list);
5046                         raid5_wakeup_stripe_thread(sh);
5047                 }
5048         }
5049 }
5050
5051 static void activate_bit_delay(struct r5conf *conf,
5052         struct list_head *temp_inactive_list)
5053 {
5054         /* device_lock is held */
5055         struct list_head head;
5056         list_add(&head, &conf->bitmap_list);
5057         list_del_init(&conf->bitmap_list);
5058         while (!list_empty(&head)) {
5059                 struct stripe_head *sh = list_entry(head.next, struct stripe_head, lru);
5060                 int hash;
5061                 list_del_init(&sh->lru);
5062                 atomic_inc(&sh->count);
5063                 hash = sh->hash_lock_index;
5064                 __release_stripe(conf, sh, &temp_inactive_list[hash]);
5065         }
5066 }
5067
5068 static int raid5_congested(struct mddev *mddev, int bits)
5069 {
5070         struct r5conf *conf = mddev->private;
5071
5072         /* No difference between reads and writes.  Just check
5073          * how busy the stripe_cache is
5074          */
5075
5076         if (test_bit(R5_INACTIVE_BLOCKED, &conf->cache_state))
5077                 return 1;
5078
5079         /* Also checks whether there is pressure on r5cache log space */
5080         if (test_bit(R5C_LOG_TIGHT, &conf->cache_state))
5081                 return 1;
5082         if (conf->quiesce)
5083                 return 1;
5084         if (atomic_read(&conf->empty_inactive_list_nr))
5085                 return 1;
5086
5087         return 0;
5088 }
5089
5090 static int in_chunk_boundary(struct mddev *mddev, struct bio *bio)
5091 {
5092         struct r5conf *conf = mddev->private;
5093         sector_t sector = bio->bi_iter.bi_sector;
5094         unsigned int chunk_sectors;
5095         unsigned int bio_sectors = bio_sectors(bio);
5096
5097         WARN_ON_ONCE(bio->bi_partno);
5098
5099         chunk_sectors = min(conf->chunk_sectors, conf->prev_chunk_sectors);
5100         return  chunk_sectors >=
5101                 ((sector & (chunk_sectors - 1)) + bio_sectors);
5102 }
5103
5104 /*
5105  *  add bio to the retry LIFO  ( in O(1) ... we are in interrupt )
5106  *  later sampled by raid5d.
5107  */
5108 static void add_bio_to_retry(struct bio *bi,struct r5conf *conf)
5109 {
5110         unsigned long flags;
5111
5112         spin_lock_irqsave(&conf->device_lock, flags);
5113
5114         bi->bi_next = conf->retry_read_aligned_list;
5115         conf->retry_read_aligned_list = bi;
5116
5117         spin_unlock_irqrestore(&conf->device_lock, flags);
5118         md_wakeup_thread(conf->mddev->thread);
5119 }
5120
5121 static struct bio *remove_bio_from_retry(struct r5conf *conf,
5122                                          unsigned int *offset)
5123 {
5124         struct bio *bi;
5125
5126         bi = conf->retry_read_aligned;
5127         if (bi) {
5128                 *offset = conf->retry_read_offset;
5129                 conf->retry_read_aligned = NULL;
5130                 return bi;
5131         }
5132         bi = conf->retry_read_aligned_list;
5133         if(bi) {
5134                 conf->retry_read_aligned_list = bi->bi_next;
5135                 bi->bi_next = NULL;
5136                 *offset = 0;
5137         }
5138
5139         return bi;
5140 }
5141
5142 /*
5143  *  The "raid5_align_endio" should check if the read succeeded and if it
5144  *  did, call bio_endio on the original bio (having bio_put the new bio
5145  *  first).
5146  *  If the read failed..
5147  */
5148 static void raid5_align_endio(struct bio *bi)
5149 {
5150         struct bio* raid_bi  = bi->bi_private;
5151         struct mddev *mddev;
5152         struct r5conf *conf;
5153         struct md_rdev *rdev;
5154         blk_status_t error = bi->bi_status;
5155
5156         bio_put(bi);
5157
5158         rdev = (void*)raid_bi->bi_next;
5159         raid_bi->bi_next = NULL;
5160         mddev = rdev->mddev;
5161         conf = mddev->private;
5162
5163         rdev_dec_pending(rdev, conf->mddev);
5164
5165         if (!error) {
5166                 bio_endio(raid_bi);
5167                 if (atomic_dec_and_test(&conf->active_aligned_reads))
5168                         wake_up(&conf->wait_for_quiescent);
5169                 return;
5170         }
5171
5172         pr_debug("raid5_align_endio : io error...handing IO for a retry\n");
5173
5174         add_bio_to_retry(raid_bi, conf);
5175 }
5176
5177 static int raid5_read_one_chunk(struct mddev *mddev, struct bio *raid_bio)
5178 {
5179         struct r5conf *conf = mddev->private;
5180         int dd_idx;
5181         struct bio* align_bi;
5182         struct md_rdev *rdev;
5183         sector_t end_sector;
5184
5185         if (!in_chunk_boundary(mddev, raid_bio)) {
5186                 pr_debug("%s: non aligned\n", __func__);
5187                 return 0;
5188         }
5189         /*
5190          * use bio_clone_fast to make a copy of the bio
5191          */
5192         align_bi = bio_clone_fast(raid_bio, GFP_NOIO, mddev->bio_set);
5193         if (!align_bi)
5194                 return 0;
5195         /*
5196          *   set bi_end_io to a new function, and set bi_private to the
5197          *     original bio.
5198          */
5199         align_bi->bi_end_io  = raid5_align_endio;
5200         align_bi->bi_private = raid_bio;
5201         /*
5202          *      compute position
5203          */
5204         align_bi->bi_iter.bi_sector =
5205                 raid5_compute_sector(conf, raid_bio->bi_iter.bi_sector,
5206                                      0, &dd_idx, NULL);
5207
5208         end_sector = bio_end_sector(align_bi);
5209         rcu_read_lock();
5210         rdev = rcu_dereference(conf->disks[dd_idx].replacement);
5211         if (!rdev || test_bit(Faulty, &rdev->flags) ||
5212             rdev->recovery_offset < end_sector) {
5213                 rdev = rcu_dereference(conf->disks[dd_idx].rdev);
5214                 if (rdev &&
5215                     (test_bit(Faulty, &rdev->flags) ||
5216                     !(test_bit(In_sync, &rdev->flags) ||
5217                       rdev->recovery_offset >= end_sector)))
5218                         rdev = NULL;
5219         }
5220
5221         if (r5c_big_stripe_cached(conf, align_bi->bi_iter.bi_sector)) {
5222                 rcu_read_unlock();
5223                 bio_put(align_bi);
5224                 return 0;
5225         }
5226
5227         if (rdev) {
5228                 sector_t first_bad;
5229                 int bad_sectors;
5230
5231                 atomic_inc(&rdev->nr_pending);
5232                 rcu_read_unlock();
5233                 raid_bio->bi_next = (void*)rdev;
5234                 bio_set_dev(align_bi, rdev->bdev);
5235                 bio_clear_flag(align_bi, BIO_SEG_VALID);
5236
5237                 if (is_badblock(rdev, align_bi->bi_iter.bi_sector,
5238                                 bio_sectors(align_bi),
5239                                 &first_bad, &bad_sectors)) {
5240                         bio_put(align_bi);
5241                         rdev_dec_pending(rdev, mddev);
5242                         return 0;
5243                 }
5244
5245                 /* No reshape active, so we can trust rdev->data_offset */
5246                 align_bi->bi_iter.bi_sector += rdev->data_offset;
5247
5248                 spin_lock_irq(&conf->device_lock);
5249                 wait_event_lock_irq(conf->wait_for_quiescent,
5250                                     conf->quiesce == 0,
5251                                     conf->device_lock);
5252                 atomic_inc(&conf->active_aligned_reads);
5253                 spin_unlock_irq(&conf->device_lock);
5254
5255                 if (mddev->gendisk)
5256                         trace_block_bio_remap(align_bi->bi_disk->queue,
5257                                               align_bi, disk_devt(mddev->gendisk),
5258                                               raid_bio->bi_iter.bi_sector);
5259                 generic_make_request(align_bi);
5260                 return 1;
5261         } else {
5262                 rcu_read_unlock();
5263                 bio_put(align_bi);
5264                 return 0;
5265         }
5266 }
5267
5268 static struct bio *chunk_aligned_read(struct mddev *mddev, struct bio *raid_bio)
5269 {
5270         struct bio *split;
5271         sector_t sector = raid_bio->bi_iter.bi_sector;
5272         unsigned chunk_sects = mddev->chunk_sectors;
5273         unsigned sectors = chunk_sects - (sector & (chunk_sects-1));
5274
5275         if (sectors < bio_sectors(raid_bio)) {
5276                 struct r5conf *conf = mddev->private;
5277                 split = bio_split(raid_bio, sectors, GFP_NOIO, conf->bio_split);
5278                 bio_chain(split, raid_bio);
5279                 generic_make_request(raid_bio);
5280                 raid_bio = split;
5281         }
5282
5283         if (!raid5_read_one_chunk(mddev, raid_bio))
5284                 return raid_bio;
5285
5286         return NULL;
5287 }
5288
5289 /* __get_priority_stripe - get the next stripe to process
5290  *
5291  * Full stripe writes are allowed to pass preread active stripes up until
5292  * the bypass_threshold is exceeded.  In general the bypass_count
5293  * increments when the handle_list is handled before the hold_list; however, it
5294  * will not be incremented when STRIPE_IO_STARTED is sampled set signifying a
5295  * stripe with in flight i/o.  The bypass_count will be reset when the
5296  * head of the hold_list has changed, i.e. the head was promoted to the
5297  * handle_list.
5298  */
5299 static struct stripe_head *__get_priority_stripe(struct r5conf *conf, int group)
5300 {
5301         struct stripe_head *sh, *tmp;
5302         struct list_head *handle_list = NULL;
5303         struct r5worker_group *wg;
5304         bool second_try = !r5c_is_writeback(conf->log) &&
5305                 !r5l_log_disk_error(conf);
5306         bool try_loprio = test_bit(R5C_LOG_TIGHT, &conf->cache_state) ||
5307                 r5l_log_disk_error(conf);
5308
5309 again:
5310         wg = NULL;
5311         sh = NULL;
5312         if (conf->worker_cnt_per_group == 0) {
5313                 handle_list = try_loprio ? &conf->loprio_list :
5314                                         &conf->handle_list;
5315         } else if (group != ANY_GROUP) {
5316                 handle_list = try_loprio ? &conf->worker_groups[group].loprio_list :
5317                                 &conf->worker_groups[group].handle_list;
5318                 wg = &conf->worker_groups[group];
5319         } else {
5320                 int i;
5321                 for (i = 0; i < conf->group_cnt; i++) {
5322                         handle_list = try_loprio ? &conf->worker_groups[i].loprio_list :
5323                                 &conf->worker_groups[i].handle_list;
5324                         wg = &conf->worker_groups[i];
5325                         if (!list_empty(handle_list))
5326                                 break;
5327                 }
5328         }
5329
5330         pr_debug("%s: handle: %s hold: %s full_writes: %d bypass_count: %d\n",
5331                   __func__,
5332                   list_empty(handle_list) ? "empty" : "busy",
5333                   list_empty(&conf->hold_list) ? "empty" : "busy",
5334                   atomic_read(&conf->pending_full_writes), conf->bypass_count);
5335
5336         if (!list_empty(handle_list)) {
5337                 sh = list_entry(handle_list->next, typeof(*sh), lru);
5338
5339                 if (list_empty(&conf->hold_list))
5340                         conf->bypass_count = 0;
5341                 else if (!test_bit(STRIPE_IO_STARTED, &sh->state)) {
5342                         if (conf->hold_list.next == conf->last_hold)
5343                                 conf->bypass_count++;
5344                         else {
5345                                 conf->last_hold = conf->hold_list.next;
5346                                 conf->bypass_count -= conf->bypass_threshold;
5347                                 if (conf->bypass_count < 0)
5348                                         conf->bypass_count = 0;
5349                         }
5350                 }
5351         } else if (!list_empty(&conf->hold_list) &&
5352                    ((conf->bypass_threshold &&
5353                      conf->bypass_count > conf->bypass_threshold) ||
5354                     atomic_read(&conf->pending_full_writes) == 0)) {
5355
5356                 list_for_each_entry(tmp, &conf->hold_list,  lru) {
5357                         if (conf->worker_cnt_per_group == 0 ||
5358                             group == ANY_GROUP ||
5359                             !cpu_online(tmp->cpu) ||
5360                             cpu_to_group(tmp->cpu) == group) {
5361                                 sh = tmp;
5362                                 break;
5363                         }
5364                 }
5365
5366                 if (sh) {
5367                         conf->bypass_count -= conf->bypass_threshold;
5368                         if (conf->bypass_count < 0)
5369                                 conf->bypass_count = 0;
5370                 }
5371                 wg = NULL;
5372         }
5373
5374         if (!sh) {
5375                 if (second_try)
5376                         return NULL;
5377                 second_try = true;
5378                 try_loprio = !try_loprio;
5379                 goto again;
5380         }
5381
5382         if (wg) {
5383                 wg->stripes_cnt--;
5384                 sh->group = NULL;
5385         }
5386         list_del_init(&sh->lru);
5387         BUG_ON(atomic_inc_return(&sh->count) != 1);
5388         return sh;
5389 }
5390
5391 struct raid5_plug_cb {
5392         struct blk_plug_cb      cb;
5393         struct list_head        list;
5394         struct list_head        temp_inactive_list[NR_STRIPE_HASH_LOCKS];
5395 };
5396
5397 static void raid5_unplug(struct blk_plug_cb *blk_cb, bool from_schedule)
5398 {
5399         struct raid5_plug_cb *cb = container_of(
5400                 blk_cb, struct raid5_plug_cb, cb);
5401         struct stripe_head *sh;
5402         struct mddev *mddev = cb->cb.data;
5403         struct r5conf *conf = mddev->private;
5404         int cnt = 0;
5405         int hash;
5406
5407         if (cb->list.next && !list_empty(&cb->list)) {
5408                 spin_lock_irq(&conf->device_lock);
5409                 while (!list_empty(&cb->list)) {
5410                         sh = list_first_entry(&cb->list, struct stripe_head, lru);
5411                         list_del_init(&sh->lru);
5412                         /*
5413                          * avoid race release_stripe_plug() sees
5414                          * STRIPE_ON_UNPLUG_LIST clear but the stripe
5415                          * is still in our list
5416                          */
5417                         smp_mb__before_atomic();
5418                         clear_bit(STRIPE_ON_UNPLUG_LIST, &sh->state);
5419                         /*
5420                          * STRIPE_ON_RELEASE_LIST could be set here. In that
5421                          * case, the count is always > 1 here
5422                          */
5423                         hash = sh->hash_lock_index;
5424                         __release_stripe(conf, sh, &cb->temp_inactive_list[hash]);
5425                         cnt++;
5426                 }
5427                 spin_unlock_irq(&conf->device_lock);
5428         }
5429         release_inactive_stripe_list(conf, cb->temp_inactive_list,
5430                                      NR_STRIPE_HASH_LOCKS);
5431         if (mddev->queue)
5432                 trace_block_unplug(mddev->queue, cnt, !from_schedule);
5433         kfree(cb);
5434 }
5435
5436 static void release_stripe_plug(struct mddev *mddev,
5437                                 struct stripe_head *sh)
5438 {
5439         struct blk_plug_cb *blk_cb = blk_check_plugged(
5440                 raid5_unplug, mddev,
5441                 sizeof(struct raid5_plug_cb));
5442         struct raid5_plug_cb *cb;
5443
5444         if (!blk_cb) {
5445                 raid5_release_stripe(sh);
5446                 return;
5447         }
5448
5449         cb = container_of(blk_cb, struct raid5_plug_cb, cb);
5450
5451         if (cb->list.next == NULL) {
5452                 int i;
5453                 INIT_LIST_HEAD(&cb->list);
5454                 for (i = 0; i < NR_STRIPE_HASH_LOCKS; i++)
5455                         INIT_LIST_HEAD(cb->temp_inactive_list + i);
5456         }
5457
5458         if (!test_and_set_bit(STRIPE_ON_UNPLUG_LIST, &sh->state))
5459                 list_add_tail(&sh->lru, &cb->list);
5460         else
5461                 raid5_release_stripe(sh);
5462 }
5463
5464 static void make_discard_request(struct mddev *mddev, struct bio *bi)
5465 {
5466         struct r5conf *conf = mddev->private;
5467         sector_t logical_sector, last_sector;
5468         struct stripe_head *sh;
5469         int stripe_sectors;
5470
5471         if (mddev->reshape_position != MaxSector)
5472                 /* Skip discard while reshape is happening */
5473                 return;
5474
5475         logical_sector = bi->bi_iter.bi_sector & ~((sector_t)STRIPE_SECTORS-1);
5476         last_sector = bi->bi_iter.bi_sector + (bi->bi_iter.bi_size>>9);
5477
5478         bi->bi_next = NULL;
5479
5480         stripe_sectors = conf->chunk_sectors *
5481                 (conf->raid_disks - conf->max_degraded);
5482         logical_sector = DIV_ROUND_UP_SECTOR_T(logical_sector,
5483                                                stripe_sectors);
5484         sector_div(last_sector, stripe_sectors);
5485
5486         logical_sector *= conf->chunk_sectors;
5487         last_sector *= conf->chunk_sectors;
5488
5489         for (; logical_sector < last_sector;
5490              logical_sector += STRIPE_SECTORS) {
5491                 DEFINE_WAIT(w);
5492                 int d;
5493         again:
5494                 sh = raid5_get_active_stripe(conf, logical_sector, 0, 0, 0);
5495                 prepare_to_wait(&conf->wait_for_overlap, &w,
5496                                 TASK_UNINTERRUPTIBLE);
5497                 set_bit(R5_Overlap, &sh->dev[sh->pd_idx].flags);
5498                 if (test_bit(STRIPE_SYNCING, &sh->state)) {
5499                         raid5_release_stripe(sh);
5500                         schedule();
5501                         goto again;
5502                 }
5503                 clear_bit(R5_Overlap, &sh->dev[sh->pd_idx].flags);
5504                 spin_lock_irq(&sh->stripe_lock);
5505                 for (d = 0; d < conf->raid_disks; d++) {
5506                         if (d == sh->pd_idx || d == sh->qd_idx)
5507                                 continue;
5508                         if (sh->dev[d].towrite || sh->dev[d].toread) {
5509                                 set_bit(R5_Overlap, &sh->dev[d].flags);
5510                                 spin_unlock_irq(&sh->stripe_lock);
5511                                 raid5_release_stripe(sh);
5512                                 schedule();
5513                                 goto again;
5514                         }
5515                 }
5516                 set_bit(STRIPE_DISCARD, &sh->state);
5517                 finish_wait(&conf->wait_for_overlap, &w);
5518                 sh->overwrite_disks = 0;
5519                 for (d = 0; d < conf->raid_disks; d++) {
5520                         if (d == sh->pd_idx || d == sh->qd_idx)
5521                                 continue;
5522                         sh->dev[d].towrite = bi;
5523                         set_bit(R5_OVERWRITE, &sh->dev[d].flags);
5524                         bio_inc_remaining(bi);
5525                         md_write_inc(mddev, bi);
5526                         sh->overwrite_disks++;
5527                 }
5528                 spin_unlock_irq(&sh->stripe_lock);
5529                 if (conf->mddev->bitmap) {
5530                         for (d = 0;
5531                              d < conf->raid_disks - conf->max_degraded;
5532                              d++)
5533                                 bitmap_startwrite(mddev->bitmap,
5534                                                   sh->sector,
5535                                                   STRIPE_SECTORS,
5536                                                   0);
5537                         sh->bm_seq = conf->seq_flush + 1;
5538                         set_bit(STRIPE_BIT_DELAY, &sh->state);
5539                 }
5540
5541                 set_bit(STRIPE_HANDLE, &sh->state);
5542                 clear_bit(STRIPE_DELAYED, &sh->state);
5543                 if (!test_and_set_bit(STRIPE_PREREAD_ACTIVE, &sh->state))
5544                         atomic_inc(&conf->preread_active_stripes);
5545                 release_stripe_plug(mddev, sh);
5546         }
5547
5548         bio_endio(bi);
5549 }
5550
5551 static bool raid5_make_request(struct mddev *mddev, struct bio * bi)
5552 {
5553         struct r5conf *conf = mddev->private;
5554         int dd_idx;
5555         sector_t new_sector;
5556         sector_t logical_sector, last_sector;
5557         struct stripe_head *sh;
5558         const int rw = bio_data_dir(bi);
5559         DEFINE_WAIT(w);
5560         bool do_prepare;
5561         bool do_flush = false;
5562
5563         if (unlikely(bi->bi_opf & REQ_PREFLUSH)) {
5564                 int ret = r5l_handle_flush_request(conf->log, bi);
5565
5566                 if (ret == 0)
5567                         return true;
5568                 if (ret == -ENODEV) {
5569                         md_flush_request(mddev, bi);
5570                         return true;
5571                 }
5572                 /* ret == -EAGAIN, fallback */
5573                 /*
5574                  * if r5l_handle_flush_request() didn't clear REQ_PREFLUSH,
5575                  * we need to flush journal device
5576                  */
5577                 do_flush = bi->bi_opf & REQ_PREFLUSH;
5578         }
5579
5580         if (!md_write_start(mddev, bi))
5581                 return false;
5582         /*
5583          * If array is degraded, better not do chunk aligned read because
5584          * later we might have to read it again in order to reconstruct
5585          * data on failed drives.
5586          */
5587         if (rw == READ && mddev->degraded == 0 &&
5588             mddev->reshape_position == MaxSector) {
5589                 bi = chunk_aligned_read(mddev, bi);
5590                 if (!bi)
5591                         return true;
5592         }
5593
5594         if (unlikely(bio_op(bi) == REQ_OP_DISCARD)) {
5595                 make_discard_request(mddev, bi);
5596                 md_write_end(mddev);
5597                 return true;
5598         }
5599
5600         logical_sector = bi->bi_iter.bi_sector & ~((sector_t)STRIPE_SECTORS-1);
5601         last_sector = bio_end_sector(bi);
5602         bi->bi_next = NULL;
5603
5604         prepare_to_wait(&conf->wait_for_overlap, &w, TASK_UNINTERRUPTIBLE);
5605         for (;logical_sector < last_sector; logical_sector += STRIPE_SECTORS) {
5606                 int previous;
5607                 int seq;
5608
5609                 do_prepare = false;
5610         retry:
5611                 seq = read_seqcount_begin(&conf->gen_lock);
5612                 previous = 0;
5613                 if (do_prepare)
5614                         prepare_to_wait(&conf->wait_for_overlap, &w,
5615                                 TASK_UNINTERRUPTIBLE);
5616                 if (unlikely(conf->reshape_progress != MaxSector)) {
5617                         /* spinlock is needed as reshape_progress may be
5618                          * 64bit on a 32bit platform, and so it might be
5619                          * possible to see a half-updated value
5620                          * Of course reshape_progress could change after
5621                          * the lock is dropped, so once we get a reference
5622                          * to the stripe that we think it is, we will have
5623                          * to check again.
5624                          */
5625                         spin_lock_irq(&conf->device_lock);
5626                         if (mddev->reshape_backwards
5627                             ? logical_sector < conf->reshape_progress
5628                             : logical_sector >= conf->reshape_progress) {
5629                                 previous = 1;
5630                         } else {
5631                                 if (mddev->reshape_backwards
5632                                     ? logical_sector < conf->reshape_safe
5633                                     : logical_sector >= conf->reshape_safe) {
5634                                         spin_unlock_irq(&conf->device_lock);
5635                                         schedule();
5636                                         do_prepare = true;
5637                                         goto retry;
5638                                 }
5639                         }
5640                         spin_unlock_irq(&conf->device_lock);
5641                 }
5642
5643                 new_sector = raid5_compute_sector(conf, logical_sector,
5644                                                   previous,
5645                                                   &dd_idx, NULL);
5646                 pr_debug("raid456: raid5_make_request, sector %llu logical %llu\n",
5647                         (unsigned long long)new_sector,
5648                         (unsigned long long)logical_sector);
5649
5650                 sh = raid5_get_active_stripe(conf, new_sector, previous,
5651                                        (bi->bi_opf & REQ_RAHEAD), 0);
5652                 if (sh) {
5653                         if (unlikely(previous)) {
5654                                 /* expansion might have moved on while waiting for a
5655                                  * stripe, so we must do the range check again.
5656                                  * Expansion could still move past after this
5657                                  * test, but as we are holding a reference to
5658                                  * 'sh', we know that if that happens,
5659                                  *  STRIPE_EXPANDING will get set and the expansion
5660                                  * won't proceed until we finish with the stripe.
5661                                  */
5662                                 int must_retry = 0;
5663                                 spin_lock_irq(&conf->device_lock);
5664                                 if (mddev->reshape_backwards
5665                                     ? logical_sector >= conf->reshape_progress
5666                                     : logical_sector < conf->reshape_progress)
5667                                         /* mismatch, need to try again */
5668                                         must_retry = 1;
5669                                 spin_unlock_irq(&conf->device_lock);
5670                                 if (must_retry) {
5671                                         raid5_release_stripe(sh);
5672                                         schedule();
5673                                         do_prepare = true;
5674                                         goto retry;
5675                                 }
5676                         }
5677                         if (read_seqcount_retry(&conf->gen_lock, seq)) {
5678                                 /* Might have got the wrong stripe_head
5679                                  * by accident
5680                                  */
5681                                 raid5_release_stripe(sh);
5682                                 goto retry;
5683                         }
5684
5685                         if (rw == WRITE &&
5686                             logical_sector >= mddev->suspend_lo &&
5687                             logical_sector < mddev->suspend_hi) {
5688                                 raid5_release_stripe(sh);
5689                                 /* As the suspend_* range is controlled by
5690                                  * userspace, we want an interruptible
5691                                  * wait.
5692                                  */
5693                                 prepare_to_wait(&conf->wait_for_overlap,
5694                                                 &w, TASK_INTERRUPTIBLE);
5695                                 if (logical_sector >= mddev->suspend_lo &&
5696                                     logical_sector < mddev->suspend_hi) {
5697                                         sigset_t full, old;
5698                                         sigfillset(&full);
5699                                         sigprocmask(SIG_BLOCK, &full, &old);
5700                                         schedule();
5701                                         sigprocmask(SIG_SETMASK, &old, NULL);
5702                                         do_prepare = true;
5703                                 }
5704                                 goto retry;
5705                         }
5706
5707                         if (test_bit(STRIPE_EXPANDING, &sh->state) ||
5708                             !add_stripe_bio(sh, bi, dd_idx, rw, previous)) {
5709                                 /* Stripe is busy expanding or
5710                                  * add failed due to overlap.  Flush everything
5711                                  * and wait a while
5712                                  */
5713                                 md_wakeup_thread(mddev->thread);
5714                                 raid5_release_stripe(sh);
5715                                 schedule();
5716                                 do_prepare = true;
5717                                 goto retry;
5718                         }
5719                         if (do_flush) {
5720                                 set_bit(STRIPE_R5C_PREFLUSH, &sh->state);
5721                                 /* we only need flush for one stripe */
5722                                 do_flush = false;
5723                         }
5724
5725                         set_bit(STRIPE_HANDLE, &sh->state);
5726                         clear_bit(STRIPE_DELAYED, &sh->state);
5727                         if ((!sh->batch_head || sh == sh->batch_head) &&
5728                             (bi->bi_opf & REQ_SYNC) &&
5729                             !test_and_set_bit(STRIPE_PREREAD_ACTIVE, &sh->state))
5730                                 atomic_inc(&conf->preread_active_stripes);
5731                         release_stripe_plug(mddev, sh);
5732                 } else {
5733                         /* cannot get stripe for read-ahead, just give-up */
5734                         bi->bi_status = BLK_STS_IOERR;
5735                         break;
5736                 }
5737         }
5738         finish_wait(&conf->wait_for_overlap, &w);
5739
5740         if (rw == WRITE)
5741                 md_write_end(mddev);
5742         bio_endio(bi);
5743         return true;
5744 }
5745
5746 static sector_t raid5_size(struct mddev *mddev, sector_t sectors, int raid_disks);
5747
5748 static sector_t reshape_request(struct mddev *mddev, sector_t sector_nr, int *skipped)
5749 {
5750         /* reshaping is quite different to recovery/resync so it is
5751          * handled quite separately ... here.
5752          *
5753          * On each call to sync_request, we gather one chunk worth of
5754          * destination stripes and flag them as expanding.
5755          * Then we find all the source stripes and request reads.
5756          * As the reads complete, handle_stripe will copy the data
5757          * into the destination stripe and release that stripe.
5758          */
5759         struct r5conf *conf = mddev->private;
5760         struct stripe_head *sh;
5761         sector_t first_sector, last_sector;
5762         int raid_disks = conf->previous_raid_disks;
5763         int data_disks = raid_disks - conf->max_degraded;
5764         int new_data_disks = conf->raid_disks - conf->max_degraded;
5765         int i;
5766         int dd_idx;
5767         sector_t writepos, readpos, safepos;
5768         sector_t stripe_addr;
5769         int reshape_sectors;
5770         struct list_head stripes;
5771         sector_t retn;
5772
5773         if (sector_nr == 0) {
5774                 /* If restarting in the middle, skip the initial sectors */
5775                 if (mddev->reshape_backwards &&
5776                     conf->reshape_progress < raid5_size(mddev, 0, 0)) {
5777                         sector_nr = raid5_size(mddev, 0, 0)
5778                                 - conf->reshape_progress;
5779                 } else if (mddev->reshape_backwards &&
5780                            conf->reshape_progress == MaxSector) {
5781                         /* shouldn't happen, but just in case, finish up.*/
5782                         sector_nr = MaxSector;
5783                 } else if (!mddev->reshape_backwards &&
5784                            conf->reshape_progress > 0)
5785                         sector_nr = conf->reshape_progress;
5786                 sector_div(sector_nr, new_data_disks);
5787                 if (sector_nr) {
5788                         mddev->curr_resync_completed = sector_nr;
5789                         sysfs_notify(&mddev->kobj, NULL, "sync_completed");
5790                         *skipped = 1;
5791                         retn = sector_nr;
5792                         goto finish;
5793                 }
5794         }
5795
5796         /* We need to process a full chunk at a time.
5797          * If old and new chunk sizes differ, we need to process the
5798          * largest of these
5799          */
5800
5801         reshape_sectors = max(conf->chunk_sectors, conf->prev_chunk_sectors);
5802
5803         /* We update the metadata at least every 10 seconds, or when
5804          * the data about to be copied would over-write the source of
5805          * the data at the front of the range.  i.e. one new_stripe
5806          * along from reshape_progress new_maps to after where
5807          * reshape_safe old_maps to
5808          */
5809         writepos = conf->reshape_progress;
5810         sector_div(writepos, new_data_disks);
5811         readpos = conf->reshape_progress;
5812         sector_div(readpos, data_disks);
5813         safepos = conf->reshape_safe;
5814         sector_div(safepos, data_disks);
5815         if (mddev->reshape_backwards) {
5816                 BUG_ON(writepos < reshape_sectors);
5817                 writepos -= reshape_sectors;
5818                 readpos += reshape_sectors;
5819                 safepos += reshape_sectors;
5820         } else {
5821                 writepos += reshape_sectors;
5822                 /* readpos and safepos are worst-case calculations.
5823                  * A negative number is overly pessimistic, and causes
5824                  * obvious problems for unsigned storage.  So clip to 0.
5825                  */
5826                 readpos -= min_t(sector_t, reshape_sectors, readpos);
5827                 safepos -= min_t(sector_t, reshape_sectors, safepos);
5828         }
5829
5830         /* Having calculated the 'writepos' possibly use it
5831          * to set 'stripe_addr' which is where we will write to.
5832          */
5833         if (mddev->reshape_backwards) {
5834                 BUG_ON(conf->reshape_progress == 0);
5835                 stripe_addr = writepos;
5836                 BUG_ON((mddev->dev_sectors &
5837                         ~((sector_t)reshape_sectors - 1))
5838                        - reshape_sectors - stripe_addr
5839                        != sector_nr);
5840         } else {
5841                 BUG_ON(writepos != sector_nr + reshape_sectors);
5842                 stripe_addr = sector_nr;
5843         }
5844
5845         /* 'writepos' is the most advanced device address we might write.
5846          * 'readpos' is the least advanced device address we might read.
5847          * 'safepos' is the least address recorded in the metadata as having
5848          *     been reshaped.
5849          * If there is a min_offset_diff, these are adjusted either by
5850          * increasing the safepos/readpos if diff is negative, or
5851          * increasing writepos if diff is positive.
5852          * If 'readpos' is then behind 'writepos', there is no way that we can
5853          * ensure safety in the face of a crash - that must be done by userspace
5854          * making a backup of the data.  So in that case there is no particular
5855          * rush to update metadata.
5856          * Otherwise if 'safepos' is behind 'writepos', then we really need to
5857          * update the metadata to advance 'safepos' to match 'readpos' so that
5858          * we can be safe in the event of a crash.
5859          * So we insist on updating metadata if safepos is behind writepos and
5860          * readpos is beyond writepos.
5861          * In any case, update the metadata every 10 seconds.
5862          * Maybe that number should be configurable, but I'm not sure it is
5863          * worth it.... maybe it could be a multiple of safemode_delay???
5864          */
5865         if (conf->min_offset_diff < 0) {
5866                 safepos += -conf->min_offset_diff;
5867                 readpos += -conf->min_offset_diff;
5868         } else
5869                 writepos += conf->min_offset_diff;
5870
5871         if ((mddev->reshape_backwards
5872              ? (safepos > writepos && readpos < writepos)
5873              : (safepos < writepos && readpos > writepos)) ||
5874             time_after(jiffies, conf->reshape_checkpoint + 10*HZ)) {
5875                 /* Cannot proceed until we've updated the superblock... */
5876                 wait_event(conf->wait_for_overlap,
5877                            atomic_read(&conf->reshape_stripes)==0
5878                            || test_bit(MD_RECOVERY_INTR, &mddev->recovery));
5879                 if (atomic_read(&conf->reshape_stripes) != 0)
5880                         return 0;
5881                 mddev->reshape_position = conf->reshape_progress;
5882                 mddev->curr_resync_completed = sector_nr;
5883                 conf->reshape_checkpoint = jiffies;
5884                 set_bit(MD_SB_CHANGE_DEVS, &mddev->sb_flags);
5885                 md_wakeup_thread(mddev->thread);
5886                 wait_event(mddev->sb_wait, mddev->sb_flags == 0 ||
5887                            test_bit(MD_RECOVERY_INTR, &mddev->recovery));
5888                 if (test_bit(MD_RECOVERY_INTR, &mddev->recovery))
5889                         return 0;
5890                 spin_lock_irq(&conf->device_lock);
5891                 conf->reshape_safe = mddev->reshape_position;
5892                 spin_unlock_irq(&conf->device_lock);
5893                 wake_up(&conf->wait_for_overlap);
5894                 sysfs_notify(&mddev->kobj, NULL, "sync_completed");
5895         }
5896
5897         INIT_LIST_HEAD(&stripes);
5898         for (i = 0; i < reshape_sectors; i += STRIPE_SECTORS) {
5899                 int j;
5900                 int skipped_disk = 0;
5901                 sh = raid5_get_active_stripe(conf, stripe_addr+i, 0, 0, 1);
5902                 set_bit(STRIPE_EXPANDING, &sh->state);
5903                 atomic_inc(&conf->reshape_stripes);
5904                 /* If any of this stripe is beyond the end of the old
5905                  * array, then we need to zero those blocks
5906                  */
5907                 for (j=sh->disks; j--;) {
5908                         sector_t s;
5909                         if (j == sh->pd_idx)
5910                                 continue;
5911                         if (conf->level == 6 &&
5912                             j == sh->qd_idx)
5913                                 continue;
5914                         s = raid5_compute_blocknr(sh, j, 0);
5915                         if (s < raid5_size(mddev, 0, 0)) {
5916                                 skipped_disk = 1;
5917                                 continue;
5918                         }
5919                         memset(page_address(sh->dev[j].page), 0, STRIPE_SIZE);
5920                         set_bit(R5_Expanded, &sh->dev[j].flags);
5921                         set_bit(R5_UPTODATE, &sh->dev[j].flags);
5922                 }
5923                 if (!skipped_disk) {
5924                         set_bit(STRIPE_EXPAND_READY, &sh->state);
5925                         set_bit(STRIPE_HANDLE, &sh->state);
5926                 }
5927                 list_add(&sh->lru, &stripes);
5928         }
5929         spin_lock_irq(&conf->device_lock);
5930         if (mddev->reshape_backwards)
5931                 conf->reshape_progress -= reshape_sectors * new_data_disks;
5932         else
5933                 conf->reshape_progress += reshape_sectors * new_data_disks;
5934         spin_unlock_irq(&conf->device_lock);
5935         /* Ok, those stripe are ready. We can start scheduling
5936          * reads on the source stripes.
5937          * The source stripes are determined by mapping the first and last
5938          * block on the destination stripes.
5939          */
5940         first_sector =
5941                 raid5_compute_sector(conf, stripe_addr*(new_data_disks),
5942                                      1, &dd_idx, NULL);
5943         last_sector =
5944                 raid5_compute_sector(conf, ((stripe_addr+reshape_sectors)
5945                                             * new_data_disks - 1),
5946                                      1, &dd_idx, NULL);
5947         if (last_sector >= mddev->dev_sectors)
5948                 last_sector = mddev->dev_sectors - 1;
5949         while (first_sector <= last_sector) {
5950                 sh = raid5_get_active_stripe(conf, first_sector, 1, 0, 1);
5951                 set_bit(STRIPE_EXPAND_SOURCE, &sh->state);
5952                 set_bit(STRIPE_HANDLE, &sh->state);
5953                 raid5_release_stripe(sh);
5954                 first_sector += STRIPE_SECTORS;
5955         }
5956         /* Now that the sources are clearly marked, we can release
5957          * the destination stripes
5958          */
5959         while (!list_empty(&stripes)) {
5960                 sh = list_entry(stripes.next, struct stripe_head, lru);
5961                 list_del_init(&sh->lru);
5962                 raid5_release_stripe(sh);
5963         }
5964         /* If this takes us to the resync_max point where we have to pause,
5965          * then we need to write out the superblock.
5966          */
5967         sector_nr += reshape_sectors;
5968         retn = reshape_sectors;
5969 finish:
5970         if (mddev->curr_resync_completed > mddev->resync_max ||
5971             (sector_nr - mddev->curr_resync_completed) * 2
5972             >= mddev->resync_max - mddev->curr_resync_completed) {
5973                 /* Cannot proceed until we've updated the superblock... */
5974                 wait_event(conf->wait_for_overlap,
5975                            atomic_read(&conf->reshape_stripes) == 0
5976                            || test_bit(MD_RECOVERY_INTR, &mddev->recovery));
5977                 if (atomic_read(&conf->reshape_stripes) != 0)
5978                         goto ret;
5979                 mddev->reshape_position = conf->reshape_progress;
5980                 mddev->curr_resync_completed = sector_nr;
5981                 conf->reshape_checkpoint = jiffies;
5982                 set_bit(MD_SB_CHANGE_DEVS, &mddev->sb_flags);
5983                 md_wakeup_thread(mddev->thread);
5984                 wait_event(mddev->sb_wait,
5985                            !test_bit(MD_SB_CHANGE_DEVS, &mddev->sb_flags)
5986                            || test_bit(MD_RECOVERY_INTR, &mddev->recovery));
5987                 if (test_bit(MD_RECOVERY_INTR, &mddev->recovery))
5988                         goto ret;
5989                 spin_lock_irq(&conf->device_lock);
5990                 conf->reshape_safe = mddev->reshape_position;
5991                 spin_unlock_irq(&conf->device_lock);
5992                 wake_up(&conf->wait_for_overlap);
5993                 sysfs_notify(&mddev->kobj, NULL, "sync_completed");
5994         }
5995 ret:
5996         return retn;
5997 }
5998
5999 static inline sector_t raid5_sync_request(struct mddev *mddev, sector_t sector_nr,
6000                                           int *skipped)
6001 {
6002         struct r5conf *conf = mddev->private;
6003         struct stripe_head *sh;
6004         sector_t max_sector = mddev->dev_sectors;
6005         sector_t sync_blocks;
6006         int still_degraded = 0;
6007         int i;
6008
6009         if (sector_nr >= max_sector) {
6010                 /* just being told to finish up .. nothing much to do */
6011
6012                 if (test_bit(MD_RECOVERY_RESHAPE, &mddev->recovery)) {
6013                         end_reshape(conf);
6014                         return 0;
6015                 }
6016
6017                 if (mddev->curr_resync < max_sector) /* aborted */
6018                         bitmap_end_sync(mddev->bitmap, mddev->curr_resync,
6019                                         &sync_blocks, 1);
6020                 else /* completed sync */
6021                         conf->fullsync = 0;
6022                 bitmap_close_sync(mddev->bitmap);
6023
6024                 return 0;
6025         }
6026
6027         /* Allow raid5_quiesce to complete */
6028         wait_event(conf->wait_for_overlap, conf->quiesce != 2);
6029
6030         if (test_bit(MD_RECOVERY_RESHAPE, &mddev->recovery))
6031                 return reshape_request(mddev, sector_nr, skipped);
6032
6033         /* No need to check resync_max as we never do more than one
6034          * stripe, and as resync_max will always be on a chunk boundary,
6035          * if the check in md_do_sync didn't fire, there is no chance
6036          * of overstepping resync_max here
6037          */
6038
6039         /* if there is too many failed drives and we are trying
6040          * to resync, then assert that we are finished, because there is
6041          * nothing we can do.
6042          */
6043         if (mddev->degraded >= conf->max_degraded &&
6044             test_bit(MD_RECOVERY_SYNC, &mddev->recovery)) {
6045                 sector_t rv = mddev->dev_sectors - sector_nr;
6046                 *skipped = 1;
6047                 return rv;
6048         }
6049         if (!test_bit(MD_RECOVERY_REQUESTED, &mddev->recovery) &&
6050             !conf->fullsync &&
6051             !bitmap_start_sync(mddev->bitmap, sector_nr, &sync_blocks, 1) &&
6052             sync_blocks >= STRIPE_SECTORS) {
6053                 /* we can skip this block, and probably more */
6054                 sync_blocks /= STRIPE_SECTORS;
6055                 *skipped = 1;
6056                 return sync_blocks * STRIPE_SECTORS; /* keep things rounded to whole stripes */
6057         }
6058
6059         bitmap_cond_end_sync(mddev->bitmap, sector_nr, false);
6060
6061         sh = raid5_get_active_stripe(conf, sector_nr, 0, 1, 0);
6062         if (sh == NULL) {
6063                 sh = raid5_get_active_stripe(conf, sector_nr, 0, 0, 0);
6064                 /* make sure we don't swamp the stripe cache if someone else
6065                  * is trying to get access
6066                  */
6067                 schedule_timeout_uninterruptible(1);
6068         }
6069         /* Need to check if array will still be degraded after recovery/resync
6070          * Note in case of > 1 drive failures it's possible we're rebuilding
6071          * one drive while leaving another faulty drive in array.
6072          */
6073         rcu_read_lock();
6074         for (i = 0; i < conf->raid_disks; i++) {
6075                 struct md_rdev *rdev = ACCESS_ONCE(conf->disks[i].rdev);
6076
6077                 if (rdev == NULL || test_bit(Faulty, &rdev->flags))
6078                         still_degraded = 1;
6079         }
6080         rcu_read_unlock();
6081
6082         bitmap_start_sync(mddev->bitmap, sector_nr, &sync_blocks, still_degraded);
6083
6084         set_bit(STRIPE_SYNC_REQUESTED, &sh->state);
6085         set_bit(STRIPE_HANDLE, &sh->state);
6086
6087         raid5_release_stripe(sh);
6088
6089         return STRIPE_SECTORS;
6090 }
6091
6092 static int  retry_aligned_read(struct r5conf *conf, struct bio *raid_bio,
6093                                unsigned int offset)
6094 {
6095         /* We may not be able to submit a whole bio at once as there
6096          * may not be enough stripe_heads available.
6097          * We cannot pre-allocate enough stripe_heads as we may need
6098          * more than exist in the cache (if we allow ever large chunks).
6099          * So we do one stripe head at a time and record in
6100          * ->bi_hw_segments how many have been done.
6101          *
6102          * We *know* that this entire raid_bio is in one chunk, so
6103          * it will be only one 'dd_idx' and only need one call to raid5_compute_sector.
6104          */
6105         struct stripe_head *sh;
6106         int dd_idx;
6107         sector_t sector, logical_sector, last_sector;
6108         int scnt = 0;
6109         int handled = 0;
6110
6111         logical_sector = raid_bio->bi_iter.bi_sector &
6112                 ~((sector_t)STRIPE_SECTORS-1);
6113         sector = raid5_compute_sector(conf, logical_sector,
6114                                       0, &dd_idx, NULL);
6115         last_sector = bio_end_sector(raid_bio);
6116
6117         for (; logical_sector < last_sector;
6118              logical_sector += STRIPE_SECTORS,
6119                      sector += STRIPE_SECTORS,
6120                      scnt++) {
6121
6122                 if (scnt < offset)
6123                         /* already done this stripe */
6124                         continue;
6125
6126                 sh = raid5_get_active_stripe(conf, sector, 0, 1, 1);
6127
6128                 if (!sh) {
6129                         /* failed to get a stripe - must wait */
6130                         conf->retry_read_aligned = raid_bio;
6131                         conf->retry_read_offset = scnt;
6132                         return handled;
6133                 }
6134
6135                 if (!add_stripe_bio(sh, raid_bio, dd_idx, 0, 0)) {
6136                         raid5_release_stripe(sh);
6137                         conf->retry_read_aligned = raid_bio;
6138                         conf->retry_read_offset = scnt;
6139                         return handled;
6140                 }
6141
6142                 set_bit(R5_ReadNoMerge, &sh->dev[dd_idx].flags);
6143                 handle_stripe(sh);
6144                 raid5_release_stripe(sh);
6145                 handled++;
6146         }
6147
6148         bio_endio(raid_bio);
6149
6150         if (atomic_dec_and_test(&conf->active_aligned_reads))
6151                 wake_up(&conf->wait_for_quiescent);
6152         return handled;
6153 }
6154
6155 static int handle_active_stripes(struct r5conf *conf, int group,
6156                                  struct r5worker *worker,
6157                                  struct list_head *temp_inactive_list)
6158 {
6159         struct stripe_head *batch[MAX_STRIPE_BATCH], *sh;
6160         int i, batch_size = 0, hash;
6161         bool release_inactive = false;
6162
6163         while (batch_size < MAX_STRIPE_BATCH &&
6164                         (sh = __get_priority_stripe(conf, group)) != NULL)
6165                 batch[batch_size++] = sh;
6166
6167         if (batch_size == 0) {
6168                 for (i = 0; i < NR_STRIPE_HASH_LOCKS; i++)
6169                         if (!list_empty(temp_inactive_list + i))
6170                                 break;
6171                 if (i == NR_STRIPE_HASH_LOCKS) {
6172                         spin_unlock_irq(&conf->device_lock);
6173                         r5l_flush_stripe_to_raid(conf->log);
6174                         spin_lock_irq(&conf->device_lock);
6175                         return batch_size;
6176                 }
6177                 release_inactive = true;
6178         }
6179         spin_unlock_irq(&conf->device_lock);
6180
6181         release_inactive_stripe_list(conf, temp_inactive_list,
6182                                      NR_STRIPE_HASH_LOCKS);
6183
6184         r5l_flush_stripe_to_raid(conf->log);
6185         if (release_inactive) {
6186                 spin_lock_irq(&conf->device_lock);
6187                 return 0;
6188         }
6189
6190         for (i = 0; i < batch_size; i++)
6191                 handle_stripe(batch[i]);
6192         log_write_stripe_run(conf);
6193
6194         cond_resched();
6195
6196         spin_lock_irq(&conf->device_lock);
6197         for (i = 0; i < batch_size; i++) {
6198                 hash = batch[i]->hash_lock_index;
6199                 __release_stripe(conf, batch[i], &temp_inactive_list[hash]);
6200         }
6201         return batch_size;
6202 }
6203
6204 static void raid5_do_work(struct work_struct *work)
6205 {
6206         struct r5worker *worker = container_of(work, struct r5worker, work);
6207         struct r5worker_group *group = worker->group;
6208         struct r5conf *conf = group->conf;
6209         struct mddev *mddev = conf->mddev;
6210         int group_id = group - conf->worker_groups;
6211         int handled;
6212         struct blk_plug plug;
6213
6214         pr_debug("+++ raid5worker active\n");
6215
6216         blk_start_plug(&plug);
6217         handled = 0;
6218         spin_lock_irq(&conf->device_lock);
6219         while (1) {
6220                 int batch_size, released;
6221
6222                 released = release_stripe_list(conf, worker->temp_inactive_list);
6223
6224                 batch_size = handle_active_stripes(conf, group_id, worker,
6225                                                    worker->temp_inactive_list);
6226                 worker->working = false;
6227                 if (!batch_size && !released)
6228                         break;
6229                 handled += batch_size;
6230                 wait_event_lock_irq(mddev->sb_wait,
6231                         !test_bit(MD_SB_CHANGE_PENDING, &mddev->sb_flags),
6232                         conf->device_lock);
6233         }
6234         pr_debug("%d stripes handled\n", handled);
6235
6236         spin_unlock_irq(&conf->device_lock);
6237
6238         flush_deferred_bios(conf);
6239
6240         r5l_flush_stripe_to_raid(conf->log);
6241
6242         async_tx_issue_pending_all();
6243         blk_finish_plug(&plug);
6244
6245         pr_debug("--- raid5worker inactive\n");
6246 }
6247
6248 /*
6249  * This is our raid5 kernel thread.
6250  *
6251  * We scan the hash table for stripes which can be handled now.
6252  * During the scan, completed stripes are saved for us by the interrupt
6253  * handler, so that they will not have to wait for our next wakeup.
6254  */
6255 static void raid5d(struct md_thread *thread)
6256 {
6257         struct mddev *mddev = thread->mddev;
6258         struct r5conf *conf = mddev->private;
6259         int handled;
6260         struct blk_plug plug;
6261
6262         pr_debug("+++ raid5d active\n");
6263
6264         md_check_recovery(mddev);
6265
6266         blk_start_plug(&plug);
6267         handled = 0;
6268         spin_lock_irq(&conf->device_lock);
6269         while (1) {
6270                 struct bio *bio;
6271                 int batch_size, released;
6272                 unsigned int offset;
6273
6274                 released = release_stripe_list(conf, conf->temp_inactive_list);
6275                 if (released)
6276                         clear_bit(R5_DID_ALLOC, &conf->cache_state);
6277
6278                 if (
6279                     !list_empty(&conf->bitmap_list)) {
6280                         /* Now is a good time to flush some bitmap updates */
6281                         conf->seq_flush++;
6282                         spin_unlock_irq(&conf->device_lock);
6283                         bitmap_unplug(mddev->bitmap);
6284                         spin_lock_irq(&conf->device_lock);
6285                         conf->seq_write = conf->seq_flush;
6286                         activate_bit_delay(conf, conf->temp_inactive_list);
6287                 }
6288                 raid5_activate_delayed(conf);
6289
6290                 while ((bio = remove_bio_from_retry(conf, &offset))) {
6291                         int ok;
6292                         spin_unlock_irq(&conf->device_lock);
6293                         ok = retry_aligned_read(conf, bio, offset);
6294                         spin_lock_irq(&conf->device_lock);
6295                         if (!ok)
6296                                 break;
6297                         handled++;
6298                 }
6299
6300                 batch_size = handle_active_stripes(conf, ANY_GROUP, NULL,
6301                                                    conf->temp_inactive_list);
6302                 if (!batch_size && !released)
6303                         break;
6304                 handled += batch_size;
6305
6306                 if (mddev->sb_flags & ~(1 << MD_SB_CHANGE_PENDING)) {
6307                         spin_unlock_irq(&conf->device_lock);
6308                         md_check_recovery(mddev);
6309                         spin_lock_irq(&conf->device_lock);
6310                 }
6311         }
6312         pr_debug("%d stripes handled\n", handled);
6313
6314         spin_unlock_irq(&conf->device_lock);
6315         if (test_and_clear_bit(R5_ALLOC_MORE, &conf->cache_state) &&
6316             mutex_trylock(&conf->cache_size_mutex)) {
6317                 grow_one_stripe(conf, __GFP_NOWARN);
6318                 /* Set flag even if allocation failed.  This helps
6319                  * slow down allocation requests when mem is short
6320                  */
6321                 set_bit(R5_DID_ALLOC, &conf->cache_state);
6322                 mutex_unlock(&conf->cache_size_mutex);
6323         }
6324
6325         flush_deferred_bios(conf);
6326
6327         r5l_flush_stripe_to_raid(conf->log);
6328
6329         async_tx_issue_pending_all();
6330         blk_finish_plug(&plug);
6331
6332         pr_debug("--- raid5d inactive\n");
6333 }
6334
6335 static ssize_t
6336 raid5_show_stripe_cache_size(struct mddev *mddev, char *page)
6337 {
6338         struct r5conf *conf;
6339         int ret = 0;
6340         spin_lock(&mddev->lock);
6341         conf = mddev->private;
6342         if (conf)
6343                 ret = sprintf(page, "%d\n", conf->min_nr_stripes);
6344         spin_unlock(&mddev->lock);
6345         return ret;
6346 }
6347
6348 int
6349 raid5_set_cache_size(struct mddev *mddev, int size)
6350 {
6351         struct r5conf *conf = mddev->private;
6352
6353         if (size <= 16 || size > 32768)
6354                 return -EINVAL;
6355
6356         conf->min_nr_stripes = size;
6357         mutex_lock(&conf->cache_size_mutex);
6358         while (size < conf->max_nr_stripes &&
6359                drop_one_stripe(conf))
6360                 ;
6361         mutex_unlock(&conf->cache_size_mutex);
6362
6363         md_allow_write(mddev);
6364
6365         mutex_lock(&conf->cache_size_mutex);
6366         while (size > conf->max_nr_stripes)
6367                 if (!grow_one_stripe(conf, GFP_KERNEL))
6368                         break;
6369         mutex_unlock(&conf->cache_size_mutex);
6370
6371         return 0;
6372 }
6373 EXPORT_SYMBOL(raid5_set_cache_size);
6374
6375 static ssize_t
6376 raid5_store_stripe_cache_size(struct mddev *mddev, const char *page, size_t len)
6377 {
6378         struct r5conf *conf;
6379         unsigned long new;
6380         int err;
6381
6382         if (len >= PAGE_SIZE)
6383                 return -EINVAL;
6384         if (kstrtoul(page, 10, &new))
6385                 return -EINVAL;
6386         err = mddev_lock(mddev);
6387         if (err)
6388                 return err;
6389         conf = mddev->private;
6390         if (!conf)
6391                 err = -ENODEV;
6392         else
6393                 err = raid5_set_cache_size(mddev, new);
6394         mddev_unlock(mddev);
6395
6396         return err ?: len;
6397 }
6398
6399 static struct md_sysfs_entry
6400 raid5_stripecache_size = __ATTR(stripe_cache_size, S_IRUGO | S_IWUSR,
6401                                 raid5_show_stripe_cache_size,
6402                                 raid5_store_stripe_cache_size);
6403
6404 static ssize_t
6405 raid5_show_rmw_level(struct mddev  *mddev, char *page)
6406 {
6407         struct r5conf *conf = mddev->private;
6408         if (conf)
6409                 return sprintf(page, "%d\n", conf->rmw_level);
6410         else
6411                 return 0;
6412 }
6413
6414 static ssize_t
6415 raid5_store_rmw_level(struct mddev  *mddev, const char *page, size_t len)
6416 {
6417         struct r5conf *conf = mddev->private;
6418         unsigned long new;
6419
6420         if (!conf)
6421                 return -ENODEV;
6422
6423         if (len >= PAGE_SIZE)
6424                 return -EINVAL;
6425
6426         if (kstrtoul(page, 10, &new))
6427                 return -EINVAL;
6428
6429         if (new != PARITY_DISABLE_RMW && !raid6_call.xor_syndrome)
6430                 return -EINVAL;
6431
6432         if (new != PARITY_DISABLE_RMW &&
6433             new != PARITY_ENABLE_RMW &&
6434             new != PARITY_PREFER_RMW)
6435                 return -EINVAL;
6436
6437         conf->rmw_level = new;
6438         return len;
6439 }
6440
6441 static struct md_sysfs_entry
6442 raid5_rmw_level = __ATTR(rmw_level, S_IRUGO | S_IWUSR,
6443                          raid5_show_rmw_level,
6444                          raid5_store_rmw_level);
6445
6446
6447 static ssize_t
6448 raid5_show_preread_threshold(struct mddev *mddev, char *page)
6449 {
6450         struct r5conf *conf;
6451         int ret = 0;
6452         spin_lock(&mddev->lock);
6453         conf = mddev->private;
6454         if (conf)
6455                 ret = sprintf(page, "%d\n", conf->bypass_threshold);
6456         spin_unlock(&mddev->lock);
6457         return ret;
6458 }
6459
6460 static ssize_t
6461 raid5_store_preread_threshold(struct mddev *mddev, const char *page, size_t len)
6462 {
6463         struct r5conf *conf;
6464         unsigned long new;
6465         int err;
6466
6467         if (len >= PAGE_SIZE)
6468                 return -EINVAL;
6469         if (kstrtoul(page, 10, &new))
6470                 return -EINVAL;
6471
6472         err = mddev_lock(mddev);
6473         if (err)
6474                 return err;
6475         conf = mddev->private;
6476         if (!conf)
6477                 err = -ENODEV;
6478         else if (new > conf->min_nr_stripes)
6479                 err = -EINVAL;
6480         else
6481                 conf->bypass_threshold = new;
6482         mddev_unlock(mddev);
6483         return err ?: len;
6484 }
6485
6486 static struct md_sysfs_entry
6487 raid5_preread_bypass_threshold = __ATTR(preread_bypass_threshold,
6488                                         S_IRUGO | S_IWUSR,
6489                                         raid5_show_preread_threshold,
6490                                         raid5_store_preread_threshold);
6491
6492 static ssize_t
6493 raid5_show_skip_copy(struct mddev *mddev, char *page)
6494 {
6495         struct r5conf *conf;
6496         int ret = 0;
6497         spin_lock(&mddev->lock);
6498         conf = mddev->private;
6499         if (conf)
6500                 ret = sprintf(page, "%d\n", conf->skip_copy);
6501         spin_unlock(&mddev->lock);
6502         return ret;
6503 }
6504
6505 static ssize_t
6506 raid5_store_skip_copy(struct mddev *mddev, const char *page, size_t len)
6507 {
6508         struct r5conf *conf;
6509         unsigned long new;
6510         int err;
6511
6512         if (len >= PAGE_SIZE)
6513                 return -EINVAL;
6514         if (kstrtoul(page, 10, &new))
6515                 return -EINVAL;
6516         new = !!new;
6517
6518         err = mddev_lock(mddev);
6519         if (err)
6520                 return err;
6521         conf = mddev->private;
6522         if (!conf)
6523                 err = -ENODEV;
6524         else if (new != conf->skip_copy) {
6525                 mddev_suspend(mddev);
6526                 conf->skip_copy = new;
6527                 if (new)
6528                         mddev->queue->backing_dev_info->capabilities |=
6529                                 BDI_CAP_STABLE_WRITES;
6530                 else
6531                         mddev->queue->backing_dev_info->capabilities &=
6532                                 ~BDI_CAP_STABLE_WRITES;
6533                 mddev_resume(mddev);
6534         }
6535         mddev_unlock(mddev);
6536         return err ?: len;
6537 }
6538
6539 static struct md_sysfs_entry
6540 raid5_skip_copy = __ATTR(skip_copy, S_IRUGO | S_IWUSR,
6541                                         raid5_show_skip_copy,
6542                                         raid5_store_skip_copy);
6543
6544 static ssize_t
6545 stripe_cache_active_show(struct mddev *mddev, char *page)
6546 {
6547         struct r5conf *conf = mddev->private;
6548         if (conf)
6549                 return sprintf(page, "%d\n", atomic_read(&conf->active_stripes));
6550         else
6551                 return 0;
6552 }
6553
6554 static struct md_sysfs_entry
6555 raid5_stripecache_active = __ATTR_RO(stripe_cache_active);
6556
6557 static ssize_t
6558 raid5_show_group_thread_cnt(struct mddev *mddev, char *page)
6559 {
6560         struct r5conf *conf;
6561         int ret = 0;
6562         spin_lock(&mddev->lock);
6563         conf = mddev->private;
6564         if (conf)
6565                 ret = sprintf(page, "%d\n", conf->worker_cnt_per_group);
6566         spin_unlock(&mddev->lock);
6567         return ret;
6568 }
6569
6570 static int alloc_thread_groups(struct r5conf *conf, int cnt,
6571                                int *group_cnt,
6572                                int *worker_cnt_per_group,
6573                                struct r5worker_group **worker_groups);
6574 static ssize_t
6575 raid5_store_group_thread_cnt(struct mddev *mddev, const char *page, size_t len)
6576 {
6577         struct r5conf *conf;
6578         unsigned long new;
6579         int err;
6580         struct r5worker_group *new_groups, *old_groups;
6581         int group_cnt, worker_cnt_per_group;
6582
6583         if (len >= PAGE_SIZE)
6584                 return -EINVAL;
6585         if (kstrtoul(page, 10, &new))
6586                 return -EINVAL;
6587
6588         err = mddev_lock(mddev);
6589         if (err)
6590                 return err;
6591         conf = mddev->private;
6592         if (!conf)
6593                 err = -ENODEV;
6594         else if (new != conf->worker_cnt_per_group) {
6595                 mddev_suspend(mddev);
6596
6597                 old_groups = conf->worker_groups;
6598                 if (old_groups)
6599                         flush_workqueue(raid5_wq);
6600
6601                 err = alloc_thread_groups(conf, new,
6602                                           &group_cnt, &worker_cnt_per_group,
6603                                           &new_groups);
6604                 if (!err) {
6605                         spin_lock_irq(&conf->device_lock);
6606                         conf->group_cnt = group_cnt;
6607                         conf->worker_cnt_per_group = worker_cnt_per_group;
6608                         conf->worker_groups = new_groups;
6609                         spin_unlock_irq(&conf->device_lock);
6610
6611                         if (old_groups)
6612                                 kfree(old_groups[0].workers);
6613                         kfree(old_groups);
6614                 }
6615                 mddev_resume(mddev);
6616         }
6617         mddev_unlock(mddev);
6618
6619         return err ?: len;
6620 }
6621
6622 static struct md_sysfs_entry
6623 raid5_group_thread_cnt = __ATTR(group_thread_cnt, S_IRUGO | S_IWUSR,
6624                                 raid5_show_group_thread_cnt,
6625                                 raid5_store_group_thread_cnt);
6626
6627 static struct attribute *raid5_attrs[] =  {
6628         &raid5_stripecache_size.attr,
6629         &raid5_stripecache_active.attr,
6630         &raid5_preread_bypass_threshold.attr,
6631         &raid5_group_thread_cnt.attr,
6632         &raid5_skip_copy.attr,
6633         &raid5_rmw_level.attr,
6634         &r5c_journal_mode.attr,
6635         NULL,
6636 };
6637 static struct attribute_group raid5_attrs_group = {
6638         .name = NULL,
6639         .attrs = raid5_attrs,
6640 };
6641
6642 static int alloc_thread_groups(struct r5conf *conf, int cnt,
6643                                int *group_cnt,
6644                                int *worker_cnt_per_group,
6645                                struct r5worker_group **worker_groups)
6646 {
6647         int i, j, k;
6648         ssize_t size;
6649         struct r5worker *workers;
6650
6651         *worker_cnt_per_group = cnt;
6652         if (cnt == 0) {
6653                 *group_cnt = 0;
6654                 *worker_groups = NULL;
6655                 return 0;
6656         }
6657         *group_cnt = num_possible_nodes();
6658         size = sizeof(struct r5worker) * cnt;
6659         workers = kzalloc(size * *group_cnt, GFP_NOIO);
6660         *worker_groups = kzalloc(sizeof(struct r5worker_group) *
6661                                 *group_cnt, GFP_NOIO);
6662         if (!*worker_groups || !workers) {
6663                 kfree(workers);
6664                 kfree(*worker_groups);
6665                 return -ENOMEM;
6666         }
6667
6668         for (i = 0; i < *group_cnt; i++) {
6669                 struct r5worker_group *group;
6670
6671                 group = &(*worker_groups)[i];
6672                 INIT_LIST_HEAD(&group->handle_list);
6673                 INIT_LIST_HEAD(&group->loprio_list);
6674                 group->conf = conf;
6675                 group->workers = workers + i * cnt;
6676
6677                 for (j = 0; j < cnt; j++) {
6678                         struct r5worker *worker = group->workers + j;
6679                         worker->group = group;
6680                         INIT_WORK(&worker->work, raid5_do_work);
6681
6682                         for (k = 0; k < NR_STRIPE_HASH_LOCKS; k++)
6683                                 INIT_LIST_HEAD(worker->temp_inactive_list + k);
6684                 }
6685         }
6686
6687         return 0;
6688 }
6689
6690 static void free_thread_groups(struct r5conf *conf)
6691 {
6692         if (conf->worker_groups)
6693                 kfree(conf->worker_groups[0].workers);
6694         kfree(conf->worker_groups);
6695         conf->worker_groups = NULL;
6696 }
6697
6698 static sector_t
6699 raid5_size(struct mddev *mddev, sector_t sectors, int raid_disks)
6700 {
6701         struct r5conf *conf = mddev->private;
6702
6703         if (!sectors)
6704                 sectors = mddev->dev_sectors;
6705         if (!raid_disks)
6706                 /* size is defined by the smallest of previous and new size */
6707                 raid_disks = min(conf->raid_disks, conf->previous_raid_disks);
6708
6709         sectors &= ~((sector_t)conf->chunk_sectors - 1);
6710         sectors &= ~((sector_t)conf->prev_chunk_sectors - 1);
6711         return sectors * (raid_disks - conf->max_degraded);
6712 }
6713
6714 static void free_scratch_buffer(struct r5conf *conf, struct raid5_percpu *percpu)
6715 {
6716         safe_put_page(percpu->spare_page);
6717         if (percpu->scribble)
6718                 flex_array_free(percpu->scribble);
6719         percpu->spare_page = NULL;
6720         percpu->scribble = NULL;
6721 }
6722
6723 static int alloc_scratch_buffer(struct r5conf *conf, struct raid5_percpu *percpu)
6724 {
6725         if (conf->level == 6 && !percpu->spare_page)
6726                 percpu->spare_page = alloc_page(GFP_KERNEL);
6727         if (!percpu->scribble)
6728                 percpu->scribble = scribble_alloc(max(conf->raid_disks,
6729                                                       conf->previous_raid_disks),
6730                                                   max(conf->chunk_sectors,
6731                                                       conf->prev_chunk_sectors)
6732                                                    / STRIPE_SECTORS,
6733                                                   GFP_KERNEL);
6734
6735         if (!percpu->scribble || (conf->level == 6 && !percpu->spare_page)) {
6736                 free_scratch_buffer(conf, percpu);
6737                 return -ENOMEM;
6738         }
6739
6740         return 0;
6741 }
6742
6743 static int raid456_cpu_dead(unsigned int cpu, struct hlist_node *node)
6744 {
6745         struct r5conf *conf = hlist_entry_safe(node, struct r5conf, node);
6746
6747         free_scratch_buffer(conf, per_cpu_ptr(conf->percpu, cpu));
6748         return 0;
6749 }
6750
6751 static void raid5_free_percpu(struct r5conf *conf)
6752 {
6753         if (!conf->percpu)
6754                 return;
6755
6756         cpuhp_state_remove_instance(CPUHP_MD_RAID5_PREPARE, &conf->node);
6757         free_percpu(conf->percpu);
6758 }
6759
6760 static void free_conf(struct r5conf *conf)
6761 {
6762         int i;
6763
6764         log_exit(conf);
6765
6766         if (conf->shrinker.nr_deferred)
6767                 unregister_shrinker(&conf->shrinker);
6768
6769         free_thread_groups(conf);
6770         shrink_stripes(conf);
6771         raid5_free_percpu(conf);
6772         for (i = 0; i < conf->pool_size; i++)
6773                 if (conf->disks[i].extra_page)
6774                         put_page(conf->disks[i].extra_page);
6775         kfree(conf->disks);
6776         if (conf->bio_split)
6777                 bioset_free(conf->bio_split);
6778         kfree(conf->stripe_hashtbl);
6779         kfree(conf->pending_data);
6780         kfree(conf);
6781 }
6782
6783 static int raid456_cpu_up_prepare(unsigned int cpu, struct hlist_node *node)
6784 {
6785         struct r5conf *conf = hlist_entry_safe(node, struct r5conf, node);
6786         struct raid5_percpu *percpu = per_cpu_ptr(conf->percpu, cpu);
6787
6788         if (alloc_scratch_buffer(conf, percpu)) {
6789                 pr_warn("%s: failed memory allocation for cpu%u\n",
6790                         __func__, cpu);
6791                 return -ENOMEM;
6792         }
6793         return 0;
6794 }
6795
6796 static int raid5_alloc_percpu(struct r5conf *conf)
6797 {
6798         int err = 0;
6799
6800         conf->percpu = alloc_percpu(struct raid5_percpu);
6801         if (!conf->percpu)
6802                 return -ENOMEM;
6803
6804         err = cpuhp_state_add_instance(CPUHP_MD_RAID5_PREPARE, &conf->node);
6805         if (!err) {
6806                 conf->scribble_disks = max(conf->raid_disks,
6807                         conf->previous_raid_disks);
6808                 conf->scribble_sectors = max(conf->chunk_sectors,
6809                         conf->prev_chunk_sectors);
6810         }
6811         return err;
6812 }
6813
6814 static unsigned long raid5_cache_scan(struct shrinker *shrink,
6815                                       struct shrink_control *sc)
6816 {
6817         struct r5conf *conf = container_of(shrink, struct r5conf, shrinker);
6818         unsigned long ret = SHRINK_STOP;
6819
6820         if (mutex_trylock(&conf->cache_size_mutex)) {
6821                 ret= 0;
6822                 while (ret < sc->nr_to_scan &&
6823                        conf->max_nr_stripes > conf->min_nr_stripes) {
6824                         if (drop_one_stripe(conf) == 0) {
6825                                 ret = SHRINK_STOP;
6826                                 break;
6827                         }
6828                         ret++;
6829                 }
6830                 mutex_unlock(&conf->cache_size_mutex);
6831         }
6832         return ret;
6833 }
6834
6835 static unsigned long raid5_cache_count(struct shrinker *shrink,
6836                                        struct shrink_control *sc)
6837 {
6838         struct r5conf *conf = container_of(shrink, struct r5conf, shrinker);
6839
6840         if (conf->max_nr_stripes < conf->min_nr_stripes)
6841                 /* unlikely, but not impossible */
6842                 return 0;
6843         return conf->max_nr_stripes - conf->min_nr_stripes;
6844 }
6845
6846 static struct r5conf *setup_conf(struct mddev *mddev)
6847 {
6848         struct r5conf *conf;
6849         int raid_disk, memory, max_disks;
6850         struct md_rdev *rdev;
6851         struct disk_info *disk;
6852         char pers_name[6];
6853         int i;
6854         int group_cnt, worker_cnt_per_group;
6855         struct r5worker_group *new_group;
6856
6857         if (mddev->new_level != 5
6858             && mddev->new_level != 4
6859             && mddev->new_level != 6) {
6860                 pr_warn("md/raid:%s: raid level not set to 4/5/6 (%d)\n",
6861                         mdname(mddev), mddev->new_level);
6862                 return ERR_PTR(-EIO);
6863         }
6864         if ((mddev->new_level == 5
6865              && !algorithm_valid_raid5(mddev->new_layout)) ||
6866             (mddev->new_level == 6
6867              && !algorithm_valid_raid6(mddev->new_layout))) {
6868                 pr_warn("md/raid:%s: layout %d not supported\n",
6869                         mdname(mddev), mddev->new_layout);
6870                 return ERR_PTR(-EIO);
6871         }
6872         if (mddev->new_level == 6 && mddev->raid_disks < 4) {
6873                 pr_warn("md/raid:%s: not enough configured devices (%d, minimum 4)\n",
6874                         mdname(mddev), mddev->raid_disks);
6875                 return ERR_PTR(-EINVAL);
6876         }
6877
6878         if (!mddev->new_chunk_sectors ||
6879             (mddev->new_chunk_sectors << 9) % PAGE_SIZE ||
6880             !is_power_of_2(mddev->new_chunk_sectors)) {
6881                 pr_warn("md/raid:%s: invalid chunk size %d\n",
6882                         mdname(mddev), mddev->new_chunk_sectors << 9);
6883                 return ERR_PTR(-EINVAL);
6884         }
6885
6886         conf = kzalloc(sizeof(struct r5conf), GFP_KERNEL);
6887         if (conf == NULL)
6888                 goto abort;
6889         INIT_LIST_HEAD(&conf->free_list);
6890         INIT_LIST_HEAD(&conf->pending_list);
6891         conf->pending_data = kzalloc(sizeof(struct r5pending_data) *
6892                 PENDING_IO_MAX, GFP_KERNEL);
6893         if (!conf->pending_data)
6894                 goto abort;
6895         for (i = 0; i < PENDING_IO_MAX; i++)
6896                 list_add(&conf->pending_data[i].sibling, &conf->free_list);
6897         /* Don't enable multi-threading by default*/
6898         if (!alloc_thread_groups(conf, 0, &group_cnt, &worker_cnt_per_group,
6899                                  &new_group)) {
6900                 conf->group_cnt = group_cnt;
6901                 conf->worker_cnt_per_group = worker_cnt_per_group;
6902                 conf->worker_groups = new_group;
6903         } else
6904                 goto abort;
6905         spin_lock_init(&conf->device_lock);
6906         seqcount_init(&conf->gen_lock);
6907         mutex_init(&conf->cache_size_mutex);
6908         init_waitqueue_head(&conf->wait_for_quiescent);
6909         init_waitqueue_head(&conf->wait_for_stripe);
6910         init_waitqueue_head(&conf->wait_for_overlap);
6911         INIT_LIST_HEAD(&conf->handle_list);
6912         INIT_LIST_HEAD(&conf->loprio_list);
6913         INIT_LIST_HEAD(&conf->hold_list);
6914         INIT_LIST_HEAD(&conf->delayed_list);
6915         INIT_LIST_HEAD(&conf->bitmap_list);
6916         init_llist_head(&conf->released_stripes);
6917         atomic_set(&conf->active_stripes, 0);
6918         atomic_set(&conf->preread_active_stripes, 0);
6919         atomic_set(&conf->active_aligned_reads, 0);
6920         spin_lock_init(&conf->pending_bios_lock);
6921         conf->batch_bio_dispatch = true;
6922         rdev_for_each(rdev, mddev) {
6923                 if (test_bit(Journal, &rdev->flags))
6924                         continue;
6925                 if (blk_queue_nonrot(bdev_get_queue(rdev->bdev))) {
6926                         conf->batch_bio_dispatch = false;
6927                         break;
6928                 }
6929         }
6930
6931         conf->bypass_threshold = BYPASS_THRESHOLD;
6932         conf->recovery_disabled = mddev->recovery_disabled - 1;
6933
6934         conf->raid_disks = mddev->raid_disks;
6935         if (mddev->reshape_position == MaxSector)
6936                 conf->previous_raid_disks = mddev->raid_disks;
6937         else
6938                 conf->previous_raid_disks = mddev->raid_disks - mddev->delta_disks;
6939         max_disks = max(conf->raid_disks, conf->previous_raid_disks);
6940
6941         conf->disks = kzalloc(max_disks * sizeof(struct disk_info),
6942                               GFP_KERNEL);
6943
6944         if (!conf->disks)
6945                 goto abort;
6946
6947         for (i = 0; i < max_disks; i++) {
6948                 conf->disks[i].extra_page = alloc_page(GFP_KERNEL);
6949                 if (!conf->disks[i].extra_page)
6950                         goto abort;
6951         }
6952
6953         conf->bio_split = bioset_create(BIO_POOL_SIZE, 0, 0);
6954         if (!conf->bio_split)
6955                 goto abort;
6956         conf->mddev = mddev;
6957
6958         if ((conf->stripe_hashtbl = kzalloc(PAGE_SIZE, GFP_KERNEL)) == NULL)
6959                 goto abort;
6960
6961         /* We init hash_locks[0] separately to that it can be used
6962          * as the reference lock in the spin_lock_nest_lock() call
6963          * in lock_all_device_hash_locks_irq in order to convince
6964          * lockdep that we know what we are doing.
6965          */
6966         spin_lock_init(conf->hash_locks);
6967         for (i = 1; i < NR_STRIPE_HASH_LOCKS; i++)
6968                 spin_lock_init(conf->hash_locks + i);
6969
6970         for (i = 0; i < NR_STRIPE_HASH_LOCKS; i++)
6971                 INIT_LIST_HEAD(conf->inactive_list + i);
6972
6973         for (i = 0; i < NR_STRIPE_HASH_LOCKS; i++)
6974                 INIT_LIST_HEAD(conf->temp_inactive_list + i);
6975
6976         atomic_set(&conf->r5c_cached_full_stripes, 0);
6977         INIT_LIST_HEAD(&conf->r5c_full_stripe_list);
6978         atomic_set(&conf->r5c_cached_partial_stripes, 0);
6979         INIT_LIST_HEAD(&conf->r5c_partial_stripe_list);
6980         atomic_set(&conf->r5c_flushing_full_stripes, 0);
6981         atomic_set(&conf->r5c_flushing_partial_stripes, 0);
6982
6983         conf->level = mddev->new_level;
6984         conf->chunk_sectors = mddev->new_chunk_sectors;
6985         if (raid5_alloc_percpu(conf) != 0)
6986                 goto abort;
6987
6988         pr_debug("raid456: run(%s) called.\n", mdname(mddev));
6989
6990         rdev_for_each(rdev, mddev) {
6991                 raid_disk = rdev->raid_disk;
6992                 if (raid_disk >= max_disks
6993                     || raid_disk < 0 || test_bit(Journal, &rdev->flags))
6994                         continue;
6995                 disk = conf->disks + raid_disk;
6996
6997                 if (test_bit(Replacement, &rdev->flags)) {
6998                         if (disk->replacement)
6999                                 goto abort;
7000                         disk->replacement = rdev;
7001                 } else {
7002                         if (disk->rdev)
7003                                 goto abort;
7004                         disk->rdev = rdev;
7005                 }
7006
7007                 if (test_bit(In_sync, &rdev->flags)) {
7008                         char b[BDEVNAME_SIZE];
7009                         pr_info("md/raid:%s: device %s operational as raid disk %d\n",
7010                                 mdname(mddev), bdevname(rdev->bdev, b), raid_disk);
7011                 } else if (rdev->saved_raid_disk != raid_disk)
7012                         /* Cannot rely on bitmap to complete recovery */
7013                         conf->fullsync = 1;
7014         }
7015
7016         conf->level = mddev->new_level;
7017         if (conf->level == 6) {
7018                 conf->max_degraded = 2;
7019                 if (raid6_call.xor_syndrome)
7020                         conf->rmw_level = PARITY_ENABLE_RMW;
7021                 else
7022                         conf->rmw_level = PARITY_DISABLE_RMW;
7023         } else {
7024                 conf->max_degraded = 1;
7025                 conf->rmw_level = PARITY_ENABLE_RMW;
7026         }
7027         conf->algorithm = mddev->new_layout;
7028         conf->reshape_progress = mddev->reshape_position;
7029         if (conf->reshape_progress != MaxSector) {
7030                 conf->prev_chunk_sectors = mddev->chunk_sectors;
7031                 conf->prev_algo = mddev->layout;
7032         } else {
7033                 conf->prev_chunk_sectors = conf->chunk_sectors;
7034                 conf->prev_algo = conf->algorithm;
7035         }
7036
7037         conf->min_nr_stripes = NR_STRIPES;
7038         if (mddev->reshape_position != MaxSector) {
7039                 int stripes = max_t(int,
7040                         ((mddev->chunk_sectors << 9) / STRIPE_SIZE) * 4,
7041                         ((mddev->new_chunk_sectors << 9) / STRIPE_SIZE) * 4);
7042                 conf->min_nr_stripes = max(NR_STRIPES, stripes);
7043                 if (conf->min_nr_stripes != NR_STRIPES)
7044                         pr_info("md/raid:%s: force stripe size %d for reshape\n",
7045                                 mdname(mddev), conf->min_nr_stripes);
7046         }
7047         memory = conf->min_nr_stripes * (sizeof(struct stripe_head) +
7048                  max_disks * ((sizeof(struct bio) + PAGE_SIZE))) / 1024;
7049         atomic_set(&conf->empty_inactive_list_nr, NR_STRIPE_HASH_LOCKS);
7050         if (grow_stripes(conf, conf->min_nr_stripes)) {
7051                 pr_warn("md/raid:%s: couldn't allocate %dkB for buffers\n",
7052                         mdname(mddev), memory);
7053                 goto abort;
7054         } else
7055                 pr_debug("md/raid:%s: allocated %dkB\n", mdname(mddev), memory);
7056         /*
7057          * Losing a stripe head costs more than the time to refill it,
7058          * it reduces the queue depth and so can hurt throughput.
7059          * So set it rather large, scaled by number of devices.
7060          */
7061         conf->shrinker.seeks = DEFAULT_SEEKS * conf->raid_disks * 4;
7062         conf->shrinker.scan_objects = raid5_cache_scan;
7063         conf->shrinker.count_objects = raid5_cache_count;
7064         conf->shrinker.batch = 128;
7065         conf->shrinker.flags = 0;
7066         if (register_shrinker(&conf->shrinker)) {
7067                 pr_warn("md/raid:%s: couldn't register shrinker.\n",
7068                         mdname(mddev));
7069                 goto abort;
7070         }
7071
7072         sprintf(pers_name, "raid%d", mddev->new_level);
7073         conf->thread = md_register_thread(raid5d, mddev, pers_name);
7074         if (!conf->thread) {
7075                 pr_warn("md/raid:%s: couldn't allocate thread.\n",
7076                         mdname(mddev));
7077                 goto abort;
7078         }
7079
7080         return conf;
7081
7082  abort:
7083         if (conf) {
7084                 free_conf(conf);
7085                 return ERR_PTR(-EIO);
7086         } else
7087                 return ERR_PTR(-ENOMEM);
7088 }
7089
7090 static int only_parity(int raid_disk, int algo, int raid_disks, int max_degraded)
7091 {
7092         switch (algo) {
7093         case ALGORITHM_PARITY_0:
7094                 if (raid_disk < max_degraded)
7095                         return 1;
7096                 break;
7097         case ALGORITHM_PARITY_N:
7098                 if (raid_disk >= raid_disks - max_degraded)
7099                         return 1;
7100                 break;
7101         case ALGORITHM_PARITY_0_6:
7102                 if (raid_disk == 0 ||
7103                     raid_disk == raid_disks - 1)
7104                         return 1;
7105                 break;
7106         case ALGORITHM_LEFT_ASYMMETRIC_6:
7107         case ALGORITHM_RIGHT_ASYMMETRIC_6:
7108         case ALGORITHM_LEFT_SYMMETRIC_6:
7109         case ALGORITHM_RIGHT_SYMMETRIC_6:
7110                 if (raid_disk == raid_disks - 1)
7111                         return 1;
7112         }
7113         return 0;
7114 }
7115
7116 static int raid5_run(struct mddev *mddev)
7117 {
7118         struct r5conf *conf;
7119         int working_disks = 0;
7120         int dirty_parity_disks = 0;
7121         struct md_rdev *rdev;
7122         struct md_rdev *journal_dev = NULL;
7123         sector_t reshape_offset = 0;
7124         int i;
7125         long long min_offset_diff = 0;
7126         int first = 1;
7127
7128         if (mddev_init_writes_pending(mddev) < 0)
7129                 return -ENOMEM;
7130
7131         if (mddev->recovery_cp != MaxSector)
7132                 pr_notice("md/raid:%s: not clean -- starting background reconstruction\n",
7133                           mdname(mddev));
7134
7135         rdev_for_each(rdev, mddev) {
7136                 long long diff;
7137
7138                 if (test_bit(Journal, &rdev->flags)) {
7139                         journal_dev = rdev;
7140                         continue;
7141                 }
7142                 if (rdev->raid_disk < 0)
7143                         continue;
7144                 diff = (rdev->new_data_offset - rdev->data_offset);
7145                 if (first) {
7146                         min_offset_diff = diff;
7147                         first = 0;
7148                 } else if (mddev->reshape_backwards &&
7149                          diff < min_offset_diff)
7150                         min_offset_diff = diff;
7151                 else if (!mddev->reshape_backwards &&
7152                          diff > min_offset_diff)
7153                         min_offset_diff = diff;
7154         }
7155
7156         if (mddev->reshape_position != MaxSector) {
7157                 /* Check that we can continue the reshape.
7158                  * Difficulties arise if the stripe we would write to
7159                  * next is at or after the stripe we would read from next.
7160                  * For a reshape that changes the number of devices, this
7161                  * is only possible for a very short time, and mdadm makes
7162                  * sure that time appears to have past before assembling
7163                  * the array.  So we fail if that time hasn't passed.
7164                  * For a reshape that keeps the number of devices the same
7165                  * mdadm must be monitoring the reshape can keeping the
7166                  * critical areas read-only and backed up.  It will start
7167                  * the array in read-only mode, so we check for that.
7168                  */
7169                 sector_t here_new, here_old;
7170                 int old_disks;
7171                 int max_degraded = (mddev->level == 6 ? 2 : 1);
7172                 int chunk_sectors;
7173                 int new_data_disks;
7174
7175                 if (journal_dev) {
7176                         pr_warn("md/raid:%s: don't support reshape with journal - aborting.\n",
7177                                 mdname(mddev));
7178                         return -EINVAL;
7179                 }
7180
7181                 if (mddev->new_level != mddev->level) {
7182                         pr_warn("md/raid:%s: unsupported reshape required - aborting.\n",
7183                                 mdname(mddev));
7184                         return -EINVAL;
7185                 }
7186                 old_disks = mddev->raid_disks - mddev->delta_disks;
7187                 /* reshape_position must be on a new-stripe boundary, and one
7188                  * further up in new geometry must map after here in old
7189                  * geometry.
7190                  * If the chunk sizes are different, then as we perform reshape
7191                  * in units of the largest of the two, reshape_position needs
7192                  * be a multiple of the largest chunk size times new data disks.
7193                  */
7194                 here_new = mddev->reshape_position;
7195                 chunk_sectors = max(mddev->chunk_sectors, mddev->new_chunk_sectors);
7196                 new_data_disks = mddev->raid_disks - max_degraded;
7197                 if (sector_div(here_new, chunk_sectors * new_data_disks)) {
7198                         pr_warn("md/raid:%s: reshape_position not on a stripe boundary\n",
7199                                 mdname(mddev));
7200                         return -EINVAL;
7201                 }
7202                 reshape_offset = here_new * chunk_sectors;
7203                 /* here_new is the stripe we will write to */
7204                 here_old = mddev->reshape_position;
7205                 sector_div(here_old, chunk_sectors * (old_disks-max_degraded));
7206                 /* here_old is the first stripe that we might need to read
7207                  * from */
7208                 if (mddev->delta_disks == 0) {
7209                         /* We cannot be sure it is safe to start an in-place
7210                          * reshape.  It is only safe if user-space is monitoring
7211                          * and taking constant backups.
7212                          * mdadm always starts a situation like this in
7213                          * readonly mode so it can take control before
7214                          * allowing any writes.  So just check for that.
7215                          */
7216                         if (abs(min_offset_diff) >= mddev->chunk_sectors &&
7217                             abs(min_offset_diff) >= mddev->new_chunk_sectors)
7218                                 /* not really in-place - so OK */;
7219                         else if (mddev->ro == 0) {
7220                                 pr_warn("md/raid:%s: in-place reshape must be started in read-only mode - aborting\n",
7221                                         mdname(mddev));
7222                                 return -EINVAL;
7223                         }
7224                 } else if (mddev->reshape_backwards
7225                     ? (here_new * chunk_sectors + min_offset_diff <=
7226                        here_old * chunk_sectors)
7227                     : (here_new * chunk_sectors >=
7228                        here_old * chunk_sectors + (-min_offset_diff))) {
7229                         /* Reading from the same stripe as writing to - bad */
7230                         pr_warn("md/raid:%s: reshape_position too early for auto-recovery - aborting.\n",
7231                                 mdname(mddev));
7232                         return -EINVAL;
7233                 }
7234                 pr_debug("md/raid:%s: reshape will continue\n", mdname(mddev));
7235                 /* OK, we should be able to continue; */
7236         } else {
7237                 BUG_ON(mddev->level != mddev->new_level);
7238                 BUG_ON(mddev->layout != mddev->new_layout);
7239                 BUG_ON(mddev->chunk_sectors != mddev->new_chunk_sectors);
7240                 BUG_ON(mddev->delta_disks != 0);
7241         }
7242
7243         if (test_bit(MD_HAS_JOURNAL, &mddev->flags) &&
7244             test_bit(MD_HAS_PPL, &mddev->flags)) {
7245                 pr_warn("md/raid:%s: using journal device and PPL not allowed - disabling PPL\n",
7246                         mdname(mddev));
7247                 clear_bit(MD_HAS_PPL, &mddev->flags);
7248                 clear_bit(MD_HAS_MULTIPLE_PPLS, &mddev->flags);
7249         }
7250
7251         if (mddev->private == NULL)
7252                 conf = setup_conf(mddev);
7253         else
7254                 conf = mddev->private;
7255
7256         if (IS_ERR(conf))
7257                 return PTR_ERR(conf);
7258
7259         if (test_bit(MD_HAS_JOURNAL, &mddev->flags)) {
7260                 if (!journal_dev) {
7261                         pr_warn("md/raid:%s: journal disk is missing, force array readonly\n",
7262                                 mdname(mddev));
7263                         mddev->ro = 1;
7264                         set_disk_ro(mddev->gendisk, 1);
7265                 } else if (mddev->recovery_cp == MaxSector)
7266                         set_bit(MD_JOURNAL_CLEAN, &mddev->flags);
7267         }
7268
7269         conf->min_offset_diff = min_offset_diff;
7270         mddev->thread = conf->thread;
7271         conf->thread = NULL;
7272         mddev->private = conf;
7273
7274         for (i = 0; i < conf->raid_disks && conf->previous_raid_disks;
7275              i++) {
7276                 rdev = conf->disks[i].rdev;
7277                 if (!rdev && conf->disks[i].replacement) {
7278                         /* The replacement is all we have yet */
7279                         rdev = conf->disks[i].replacement;
7280                         conf->disks[i].replacement = NULL;
7281                         clear_bit(Replacement, &rdev->flags);
7282                         conf->disks[i].rdev = rdev;
7283                 }
7284                 if (!rdev)
7285                         continue;
7286                 if (conf->disks[i].replacement &&
7287                     conf->reshape_progress != MaxSector) {
7288                         /* replacements and reshape simply do not mix. */
7289                         pr_warn("md: cannot handle concurrent replacement and reshape.\n");
7290                         goto abort;
7291                 }
7292                 if (test_bit(In_sync, &rdev->flags)) {
7293                         working_disks++;
7294                         continue;
7295                 }
7296                 /* This disc is not fully in-sync.  However if it
7297                  * just stored parity (beyond the recovery_offset),
7298                  * when we don't need to be concerned about the
7299                  * array being dirty.
7300                  * When reshape goes 'backwards', we never have
7301                  * partially completed devices, so we only need
7302                  * to worry about reshape going forwards.
7303                  */
7304                 /* Hack because v0.91 doesn't store recovery_offset properly. */
7305                 if (mddev->major_version == 0 &&
7306                     mddev->minor_version > 90)
7307                         rdev->recovery_offset = reshape_offset;
7308
7309                 if (rdev->recovery_offset < reshape_offset) {
7310                         /* We need to check old and new layout */
7311                         if (!only_parity(rdev->raid_disk,
7312                                          conf->algorithm,
7313                                          conf->raid_disks,
7314                                          conf->max_degraded))
7315                                 continue;
7316                 }
7317                 if (!only_parity(rdev->raid_disk,
7318                                  conf->prev_algo,
7319                                  conf->previous_raid_disks,
7320                                  conf->max_degraded))
7321                         continue;
7322                 dirty_parity_disks++;
7323         }
7324
7325         /*
7326          * 0 for a fully functional array, 1 or 2 for a degraded array.
7327          */
7328         mddev->degraded = raid5_calc_degraded(conf);
7329
7330         if (has_failed(conf)) {
7331                 pr_crit("md/raid:%s: not enough operational devices (%d/%d failed)\n",
7332                         mdname(mddev), mddev->degraded, conf->raid_disks);
7333                 goto abort;
7334         }
7335
7336         /* device size must be a multiple of chunk size */
7337         mddev->dev_sectors &= ~(mddev->chunk_sectors - 1);
7338         mddev->resync_max_sectors = mddev->dev_sectors;
7339
7340         if (mddev->degraded > dirty_parity_disks &&
7341             mddev->recovery_cp != MaxSector) {
7342                 if (test_bit(MD_HAS_PPL, &mddev->flags))
7343                         pr_crit("md/raid:%s: starting dirty degraded array with PPL.\n",
7344                                 mdname(mddev));
7345                 else if (mddev->ok_start_degraded)
7346                         pr_crit("md/raid:%s: starting dirty degraded array - data corruption possible.\n",
7347                                 mdname(mddev));
7348                 else {
7349                         pr_crit("md/raid:%s: cannot start dirty degraded array.\n",
7350                                 mdname(mddev));
7351                         goto abort;
7352                 }
7353         }
7354
7355         pr_info("md/raid:%s: raid level %d active with %d out of %d devices, algorithm %d\n",
7356                 mdname(mddev), conf->level,
7357                 mddev->raid_disks-mddev->degraded, mddev->raid_disks,
7358                 mddev->new_layout);
7359
7360         print_raid5_conf(conf);
7361
7362         if (conf->reshape_progress != MaxSector) {
7363                 conf->reshape_safe = conf->reshape_progress;
7364                 atomic_set(&conf->reshape_stripes, 0);
7365                 clear_bit(MD_RECOVERY_SYNC, &mddev->recovery);
7366                 clear_bit(MD_RECOVERY_CHECK, &mddev->recovery);
7367                 set_bit(MD_RECOVERY_RESHAPE, &mddev->recovery);
7368                 set_bit(MD_RECOVERY_RUNNING, &mddev->recovery);
7369                 mddev->sync_thread = md_register_thread(md_do_sync, mddev,
7370                                                         "reshape");
7371         }
7372
7373         /* Ok, everything is just fine now */
7374         if (mddev->to_remove == &raid5_attrs_group)
7375                 mddev->to_remove = NULL;
7376         else if (mddev->kobj.sd &&
7377             sysfs_create_group(&mddev->kobj, &raid5_attrs_group))
7378                 pr_warn("raid5: failed to create sysfs attributes for %s\n",
7379                         mdname(mddev));
7380         md_set_array_sectors(mddev, raid5_size(mddev, 0, 0));
7381
7382         if (mddev->queue) {
7383                 int chunk_size;
7384                 /* read-ahead size must cover two whole stripes, which
7385                  * is 2 * (datadisks) * chunksize where 'n' is the
7386                  * number of raid devices
7387                  */
7388                 int data_disks = conf->previous_raid_disks - conf->max_degraded;
7389                 int stripe = data_disks *
7390                         ((mddev->chunk_sectors << 9) / PAGE_SIZE);
7391                 if (mddev->queue->backing_dev_info->ra_pages < 2 * stripe)
7392                         mddev->queue->backing_dev_info->ra_pages = 2 * stripe;
7393
7394                 chunk_size = mddev->chunk_sectors << 9;
7395                 blk_queue_io_min(mddev->queue, chunk_size);
7396                 blk_queue_io_opt(mddev->queue, chunk_size *
7397                                  (conf->raid_disks - conf->max_degraded));
7398                 mddev->queue->limits.raid_partial_stripes_expensive = 1;
7399                 /*
7400                  * We can only discard a whole stripe. It doesn't make sense to
7401                  * discard data disk but write parity disk
7402                  */
7403                 stripe = stripe * PAGE_SIZE;
7404                 /* Round up to power of 2, as discard handling
7405                  * currently assumes that */
7406                 while ((stripe-1) & stripe)
7407                         stripe = (stripe | (stripe-1)) + 1;
7408                 mddev->queue->limits.discard_alignment = stripe;
7409                 mddev->queue->limits.discard_granularity = stripe;
7410
7411                 blk_queue_max_write_same_sectors(mddev->queue, 0);
7412                 blk_queue_max_write_zeroes_sectors(mddev->queue, 0);
7413
7414                 rdev_for_each(rdev, mddev) {
7415                         disk_stack_limits(mddev->gendisk, rdev->bdev,
7416                                           rdev->data_offset << 9);
7417                         disk_stack_limits(mddev->gendisk, rdev->bdev,
7418                                           rdev->new_data_offset << 9);
7419                 }
7420
7421                 /*
7422                  * zeroing is required, otherwise data
7423                  * could be lost. Consider a scenario: discard a stripe
7424                  * (the stripe could be inconsistent if
7425                  * discard_zeroes_data is 0); write one disk of the
7426                  * stripe (the stripe could be inconsistent again
7427                  * depending on which disks are used to calculate
7428                  * parity); the disk is broken; The stripe data of this
7429                  * disk is lost.
7430                  *
7431                  * We only allow DISCARD if the sysadmin has confirmed that
7432                  * only safe devices are in use by setting a module parameter.
7433                  * A better idea might be to turn DISCARD into WRITE_ZEROES
7434                  * requests, as that is required to be safe.
7435                  */
7436                 if (devices_handle_discard_safely &&
7437                     mddev->queue->limits.max_discard_sectors >= (stripe >> 9) &&
7438                     mddev->queue->limits.discard_granularity >= stripe)
7439                         queue_flag_set_unlocked(QUEUE_FLAG_DISCARD,
7440                                                 mddev->queue);
7441                 else
7442                         queue_flag_clear_unlocked(QUEUE_FLAG_DISCARD,
7443                                                 mddev->queue);
7444
7445                 blk_queue_max_hw_sectors(mddev->queue, UINT_MAX);
7446         }
7447
7448         if (log_init(conf, journal_dev, raid5_has_ppl(conf)))
7449                 goto abort;
7450
7451         return 0;
7452 abort:
7453         md_unregister_thread(&mddev->thread);
7454         print_raid5_conf(conf);
7455         free_conf(conf);
7456         mddev->private = NULL;
7457         pr_warn("md/raid:%s: failed to run raid set.\n", mdname(mddev));
7458         return -EIO;
7459 }
7460
7461 static void raid5_free(struct mddev *mddev, void *priv)
7462 {
7463         struct r5conf *conf = priv;
7464
7465         free_conf(conf);
7466         mddev->to_remove = &raid5_attrs_group;
7467 }
7468
7469 static void raid5_status(struct seq_file *seq, struct mddev *mddev)
7470 {
7471         struct r5conf *conf = mddev->private;
7472         int i;
7473
7474         seq_printf(seq, " level %d, %dk chunk, algorithm %d", mddev->level,
7475                 conf->chunk_sectors / 2, mddev->layout);
7476         seq_printf (seq, " [%d/%d] [", conf->raid_disks, conf->raid_disks - mddev->degraded);
7477         rcu_read_lock();
7478         for (i = 0; i < conf->raid_disks; i++) {
7479                 struct md_rdev *rdev = rcu_dereference(conf->disks[i].rdev);
7480                 seq_printf (seq, "%s", rdev && test_bit(In_sync, &rdev->flags) ? "U" : "_");
7481         }
7482         rcu_read_unlock();
7483         seq_printf (seq, "]");
7484 }
7485
7486 static void print_raid5_conf (struct r5conf *conf)
7487 {
7488         int i;
7489         struct disk_info *tmp;
7490
7491         pr_debug("RAID conf printout:\n");
7492         if (!conf) {
7493                 pr_debug("(conf==NULL)\n");
7494                 return;
7495         }
7496         pr_debug(" --- level:%d rd:%d wd:%d\n", conf->level,
7497                conf->raid_disks,
7498                conf->raid_disks - conf->mddev->degraded);
7499
7500         for (i = 0; i < conf->raid_disks; i++) {
7501                 char b[BDEVNAME_SIZE];
7502                 tmp = conf->disks + i;
7503                 if (tmp->rdev)
7504                         pr_debug(" disk %d, o:%d, dev:%s\n",
7505                                i, !test_bit(Faulty, &tmp->rdev->flags),
7506                                bdevname(tmp->rdev->bdev, b));
7507         }
7508 }
7509
7510 static int raid5_spare_active(struct mddev *mddev)
7511 {
7512         int i;
7513         struct r5conf *conf = mddev->private;
7514         struct disk_info *tmp;
7515         int count = 0;
7516         unsigned long flags;
7517
7518         for (i = 0; i < conf->raid_disks; i++) {
7519                 tmp = conf->disks + i;
7520                 if (tmp->replacement
7521                     && tmp->replacement->recovery_offset == MaxSector
7522                     && !test_bit(Faulty, &tmp->replacement->flags)
7523                     && !test_and_set_bit(In_sync, &tmp->replacement->flags)) {
7524                         /* Replacement has just become active. */
7525                         if (!tmp->rdev
7526                             || !test_and_clear_bit(In_sync, &tmp->rdev->flags))
7527                                 count++;
7528                         if (tmp->rdev) {
7529                                 /* Replaced device not technically faulty,
7530                                  * but we need to be sure it gets removed
7531                                  * and never re-added.
7532                                  */
7533                                 set_bit(Faulty, &tmp->rdev->flags);
7534                                 sysfs_notify_dirent_safe(
7535                                         tmp->rdev->sysfs_state);
7536                         }
7537                         sysfs_notify_dirent_safe(tmp->replacement->sysfs_state);
7538                 } else if (tmp->rdev
7539                     && tmp->rdev->recovery_offset == MaxSector
7540                     && !test_bit(Faulty, &tmp->rdev->flags)
7541                     && !test_and_set_bit(In_sync, &tmp->rdev->flags)) {
7542                         count++;
7543                         sysfs_notify_dirent_safe(tmp->rdev->sysfs_state);
7544                 }
7545         }
7546         spin_lock_irqsave(&conf->device_lock, flags);
7547         mddev->degraded = raid5_calc_degraded(conf);
7548         spin_unlock_irqrestore(&conf->device_lock, flags);
7549         print_raid5_conf(conf);
7550         return count;
7551 }
7552
7553 static int raid5_remove_disk(struct mddev *mddev, struct md_rdev *rdev)
7554 {
7555         struct r5conf *conf = mddev->private;
7556         int err = 0;
7557         int number = rdev->raid_disk;
7558         struct md_rdev **rdevp;
7559         struct disk_info *p = conf->disks + number;
7560
7561         print_raid5_conf(conf);
7562         if (test_bit(Journal, &rdev->flags) && conf->log) {
7563                 /*
7564                  * we can't wait pending write here, as this is called in
7565                  * raid5d, wait will deadlock.
7566                  * neilb: there is no locking about new writes here,
7567                  * so this cannot be safe.
7568                  */
7569                 if (atomic_read(&conf->active_stripes) ||
7570                     atomic_read(&conf->r5c_cached_full_stripes) ||
7571                     atomic_read(&conf->r5c_cached_partial_stripes)) {
7572                         return -EBUSY;
7573                 }
7574                 log_exit(conf);
7575                 return 0;
7576         }
7577         if (rdev == p->rdev)
7578                 rdevp = &p->rdev;
7579         else if (rdev == p->replacement)
7580                 rdevp = &p->replacement;
7581         else
7582                 return 0;
7583
7584         if (number >= conf->raid_disks &&
7585             conf->reshape_progress == MaxSector)
7586                 clear_bit(In_sync, &rdev->flags);
7587
7588         if (test_bit(In_sync, &rdev->flags) ||
7589             atomic_read(&rdev->nr_pending)) {
7590                 err = -EBUSY;
7591                 goto abort;
7592         }
7593         /* Only remove non-faulty devices if recovery
7594          * isn't possible.
7595          */
7596         if (!test_bit(Faulty, &rdev->flags) &&
7597             mddev->recovery_disabled != conf->recovery_disabled &&
7598             !has_failed(conf) &&
7599             (!p->replacement || p->replacement == rdev) &&
7600             number < conf->raid_disks) {
7601                 err = -EBUSY;
7602                 goto abort;
7603         }
7604         *rdevp = NULL;
7605         if (!test_bit(RemoveSynchronized, &rdev->flags)) {
7606                 synchronize_rcu();
7607                 if (atomic_read(&rdev->nr_pending)) {
7608                         /* lost the race, try later */
7609                         err = -EBUSY;
7610                         *rdevp = rdev;
7611                 }
7612         }
7613         if (!err) {
7614                 err = log_modify(conf, rdev, false);
7615                 if (err)
7616                         goto abort;
7617         }
7618         if (p->replacement) {
7619                 /* We must have just cleared 'rdev' */
7620                 p->rdev = p->replacement;
7621                 clear_bit(Replacement, &p->replacement->flags);
7622                 smp_mb(); /* Make sure other CPUs may see both as identical
7623                            * but will never see neither - if they are careful
7624                            */
7625                 p->replacement = NULL;
7626
7627                 if (!err)
7628                         err = log_modify(conf, p->rdev, true);
7629         }
7630
7631         clear_bit(WantReplacement, &rdev->flags);
7632 abort:
7633
7634         print_raid5_conf(conf);
7635         return err;
7636 }
7637
7638 static int raid5_add_disk(struct mddev *mddev, struct md_rdev *rdev)
7639 {
7640         struct r5conf *conf = mddev->private;
7641         int err = -EEXIST;
7642         int disk;
7643         struct disk_info *p;
7644         int first = 0;
7645         int last = conf->raid_disks - 1;
7646
7647         if (test_bit(Journal, &rdev->flags)) {
7648                 if (conf->log)
7649                         return -EBUSY;
7650
7651                 rdev->raid_disk = 0;
7652                 /*
7653                  * The array is in readonly mode if journal is missing, so no
7654                  * write requests running. We should be safe
7655                  */
7656                 log_init(conf, rdev, false);
7657                 return 0;
7658         }
7659         if (mddev->recovery_disabled == conf->recovery_disabled)
7660                 return -EBUSY;
7661
7662         if (rdev->saved_raid_disk < 0 && has_failed(conf))
7663                 /* no point adding a device */
7664                 return -EINVAL;
7665
7666         if (rdev->raid_disk >= 0)
7667                 first = last = rdev->raid_disk;
7668
7669         /*
7670          * find the disk ... but prefer rdev->saved_raid_disk
7671          * if possible.
7672          */
7673         if (rdev->saved_raid_disk >= 0 &&
7674             rdev->saved_raid_disk >= first &&
7675             conf->disks[rdev->saved_raid_disk].rdev == NULL)
7676                 first = rdev->saved_raid_disk;
7677
7678         for (disk = first; disk <= last; disk++) {
7679                 p = conf->disks + disk;
7680                 if (p->rdev == NULL) {
7681                         clear_bit(In_sync, &rdev->flags);
7682                         rdev->raid_disk = disk;
7683                         if (rdev->saved_raid_disk != disk)
7684                                 conf->fullsync = 1;
7685                         rcu_assign_pointer(p->rdev, rdev);
7686
7687                         err = log_modify(conf, rdev, true);
7688
7689                         goto out;
7690                 }
7691         }
7692         for (disk = first; disk <= last; disk++) {
7693                 p = conf->disks + disk;
7694                 if (test_bit(WantReplacement, &p->rdev->flags) &&
7695                     p->replacement == NULL) {
7696                         clear_bit(In_sync, &rdev->flags);
7697                         set_bit(Replacement, &rdev->flags);
7698                         rdev->raid_disk = disk;
7699                         err = 0;
7700                         conf->fullsync = 1;
7701                         rcu_assign_pointer(p->replacement, rdev);
7702                         break;
7703                 }
7704         }
7705 out:
7706         print_raid5_conf(conf);
7707         return err;
7708 }
7709
7710 static int raid5_resize(struct mddev *mddev, sector_t sectors)
7711 {
7712         /* no resync is happening, and there is enough space
7713          * on all devices, so we can resize.
7714          * We need to make sure resync covers any new space.
7715          * If the array is shrinking we should possibly wait until
7716          * any io in the removed space completes, but it hardly seems
7717          * worth it.
7718          */
7719         sector_t newsize;
7720         struct r5conf *conf = mddev->private;
7721
7722         if (conf->log || raid5_has_ppl(conf))
7723                 return -EINVAL;
7724         sectors &= ~((sector_t)conf->chunk_sectors - 1);
7725         newsize = raid5_size(mddev, sectors, mddev->raid_disks);
7726         if (mddev->external_size &&
7727             mddev->array_sectors > newsize)
7728                 return -EINVAL;
7729         if (mddev->bitmap) {
7730                 int ret = bitmap_resize(mddev->bitmap, sectors, 0, 0);
7731                 if (ret)
7732                         return ret;
7733         }
7734         md_set_array_sectors(mddev, newsize);
7735         if (sectors > mddev->dev_sectors &&
7736             mddev->recovery_cp > mddev->dev_sectors) {
7737                 mddev->recovery_cp = mddev->dev_sectors;
7738                 set_bit(MD_RECOVERY_NEEDED, &mddev->recovery);
7739         }
7740         mddev->dev_sectors = sectors;
7741         mddev->resync_max_sectors = sectors;
7742         return 0;
7743 }
7744
7745 static int check_stripe_cache(struct mddev *mddev)
7746 {
7747         /* Can only proceed if there are plenty of stripe_heads.
7748          * We need a minimum of one full stripe,, and for sensible progress
7749          * it is best to have about 4 times that.
7750          * If we require 4 times, then the default 256 4K stripe_heads will
7751          * allow for chunk sizes up to 256K, which is probably OK.
7752          * If the chunk size is greater, user-space should request more
7753          * stripe_heads first.
7754          */
7755         struct r5conf *conf = mddev->private;
7756         if (((mddev->chunk_sectors << 9) / STRIPE_SIZE) * 4
7757             > conf->min_nr_stripes ||
7758             ((mddev->new_chunk_sectors << 9) / STRIPE_SIZE) * 4
7759             > conf->min_nr_stripes) {
7760                 pr_warn("md/raid:%s: reshape: not enough stripes.  Needed %lu\n",
7761                         mdname(mddev),
7762                         ((max(mddev->chunk_sectors, mddev->new_chunk_sectors) << 9)
7763                          / STRIPE_SIZE)*4);
7764                 return 0;
7765         }
7766         return 1;
7767 }
7768
7769 static int check_reshape(struct mddev *mddev)
7770 {
7771         struct r5conf *conf = mddev->private;
7772
7773         if (conf->log || raid5_has_ppl(conf))
7774                 return -EINVAL;
7775         if (mddev->delta_disks == 0 &&
7776             mddev->new_layout == mddev->layout &&
7777             mddev->new_chunk_sectors == mddev->chunk_sectors)
7778                 return 0; /* nothing to do */
7779         if (has_failed(conf))
7780                 return -EINVAL;
7781         if (mddev->delta_disks < 0 && mddev->reshape_position == MaxSector) {
7782                 /* We might be able to shrink, but the devices must
7783                  * be made bigger first.
7784                  * For raid6, 4 is the minimum size.
7785                  * Otherwise 2 is the minimum
7786                  */
7787                 int min = 2;
7788                 if (mddev->level == 6)
7789                         min = 4;
7790                 if (mddev->raid_disks + mddev->delta_disks < min)
7791                         return -EINVAL;
7792         }
7793
7794         if (!check_stripe_cache(mddev))
7795                 return -ENOSPC;
7796
7797         if (mddev->new_chunk_sectors > mddev->chunk_sectors ||
7798             mddev->delta_disks > 0)
7799                 if (resize_chunks(conf,
7800                                   conf->previous_raid_disks
7801                                   + max(0, mddev->delta_disks),
7802                                   max(mddev->new_chunk_sectors,
7803                                       mddev->chunk_sectors)
7804                             ) < 0)
7805                         return -ENOMEM;
7806
7807         if (conf->previous_raid_disks + mddev->delta_disks <= conf->pool_size)
7808                 return 0; /* never bother to shrink */
7809         return resize_stripes(conf, (conf->previous_raid_disks
7810                                      + mddev->delta_disks));
7811 }
7812
7813 static int raid5_start_reshape(struct mddev *mddev)
7814 {
7815         struct r5conf *conf = mddev->private;
7816         struct md_rdev *rdev;
7817         int spares = 0;
7818         unsigned long flags;
7819
7820         if (test_bit(MD_RECOVERY_RUNNING, &mddev->recovery))
7821                 return -EBUSY;
7822
7823         if (!check_stripe_cache(mddev))
7824                 return -ENOSPC;
7825
7826         if (has_failed(conf))
7827                 return -EINVAL;
7828
7829         rdev_for_each(rdev, mddev) {
7830                 if (!test_bit(In_sync, &rdev->flags)
7831                     && !test_bit(Faulty, &rdev->flags))
7832                         spares++;
7833         }
7834
7835         if (spares - mddev->degraded < mddev->delta_disks - conf->max_degraded)
7836                 /* Not enough devices even to make a degraded array
7837                  * of that size
7838                  */
7839                 return -EINVAL;
7840
7841         /* Refuse to reduce size of the array.  Any reductions in
7842          * array size must be through explicit setting of array_size
7843          * attribute.
7844          */
7845         if (raid5_size(mddev, 0, conf->raid_disks + mddev->delta_disks)
7846             < mddev->array_sectors) {
7847                 pr_warn("md/raid:%s: array size must be reduced before number of disks\n",
7848                         mdname(mddev));
7849                 return -EINVAL;
7850         }
7851
7852         atomic_set(&conf->reshape_stripes, 0);
7853         spin_lock_irq(&conf->device_lock);
7854         write_seqcount_begin(&conf->gen_lock);
7855         conf->previous_raid_disks = conf->raid_disks;
7856         conf->raid_disks += mddev->delta_disks;
7857         conf->prev_chunk_sectors = conf->chunk_sectors;
7858         conf->chunk_sectors = mddev->new_chunk_sectors;
7859         conf->prev_algo = conf->algorithm;
7860         conf->algorithm = mddev->new_layout;
7861         conf->generation++;
7862         /* Code that selects data_offset needs to see the generation update
7863          * if reshape_progress has been set - so a memory barrier needed.
7864          */
7865         smp_mb();
7866         if (mddev->reshape_backwards)
7867                 conf->reshape_progress = raid5_size(mddev, 0, 0);
7868         else
7869                 conf->reshape_progress = 0;
7870         conf->reshape_safe = conf->reshape_progress;
7871         write_seqcount_end(&conf->gen_lock);
7872         spin_unlock_irq(&conf->device_lock);
7873
7874         /* Now make sure any requests that proceeded on the assumption
7875          * the reshape wasn't running - like Discard or Read - have
7876          * completed.
7877          */
7878         mddev_suspend(mddev);
7879         mddev_resume(mddev);
7880
7881         /* Add some new drives, as many as will fit.
7882          * We know there are enough to make the newly sized array work.
7883          * Don't add devices if we are reducing the number of
7884          * devices in the array.  This is because it is not possible
7885          * to correctly record the "partially reconstructed" state of
7886          * such devices during the reshape and confusion could result.
7887          */
7888         if (mddev->delta_disks >= 0) {
7889                 rdev_for_each(rdev, mddev)
7890                         if (rdev->raid_disk < 0 &&
7891                             !test_bit(Faulty, &rdev->flags)) {
7892                                 if (raid5_add_disk(mddev, rdev) == 0) {
7893                                         if (rdev->raid_disk
7894                                             >= conf->previous_raid_disks)
7895                                                 set_bit(In_sync, &rdev->flags);
7896                                         else
7897                                                 rdev->recovery_offset = 0;
7898
7899                                         if (sysfs_link_rdev(mddev, rdev))
7900                                                 /* Failure here is OK */;
7901                                 }
7902                         } else if (rdev->raid_disk >= conf->previous_raid_disks
7903                                    && !test_bit(Faulty, &rdev->flags)) {
7904                                 /* This is a spare that was manually added */
7905                                 set_bit(In_sync, &rdev->flags);
7906                         }
7907
7908                 /* When a reshape changes the number of devices,
7909                  * ->degraded is measured against the larger of the
7910                  * pre and post number of devices.
7911                  */
7912                 spin_lock_irqsave(&conf->device_lock, flags);
7913                 mddev->degraded = raid5_calc_degraded(conf);
7914                 spin_unlock_irqrestore(&conf->device_lock, flags);
7915         }
7916         mddev->raid_disks = conf->raid_disks;
7917         mddev->reshape_position = conf->reshape_progress;
7918         set_bit(MD_SB_CHANGE_DEVS, &mddev->sb_flags);
7919
7920         clear_bit(MD_RECOVERY_SYNC, &mddev->recovery);
7921         clear_bit(MD_RECOVERY_CHECK, &mddev->recovery);
7922         clear_bit(MD_RECOVERY_DONE, &mddev->recovery);
7923         set_bit(MD_RECOVERY_RESHAPE, &mddev->recovery);
7924         set_bit(MD_RECOVERY_RUNNING, &mddev->recovery);
7925         mddev->sync_thread = md_register_thread(md_do_sync, mddev,
7926                                                 "reshape");
7927         if (!mddev->sync_thread) {
7928                 mddev->recovery = 0;
7929                 spin_lock_irq(&conf->device_lock);
7930                 write_seqcount_begin(&conf->gen_lock);
7931                 mddev->raid_disks = conf->raid_disks = conf->previous_raid_disks;
7932                 mddev->new_chunk_sectors =
7933                         conf->chunk_sectors = conf->prev_chunk_sectors;
7934                 mddev->new_layout = conf->algorithm = conf->prev_algo;
7935                 rdev_for_each(rdev, mddev)
7936                         rdev->new_data_offset = rdev->data_offset;
7937                 smp_wmb();
7938                 conf->generation --;
7939                 conf->reshape_progress = MaxSector;
7940                 mddev->reshape_position = MaxSector;
7941                 write_seqcount_end(&conf->gen_lock);
7942                 spin_unlock_irq(&conf->device_lock);
7943                 return -EAGAIN;
7944         }
7945         conf->reshape_checkpoint = jiffies;
7946         md_wakeup_thread(mddev->sync_thread);
7947         md_new_event(mddev);
7948         return 0;
7949 }
7950
7951 /* This is called from the reshape thread and should make any
7952  * changes needed in 'conf'
7953  */
7954 static void end_reshape(struct r5conf *conf)
7955 {
7956
7957         if (!test_bit(MD_RECOVERY_INTR, &conf->mddev->recovery)) {
7958
7959                 spin_lock_irq(&conf->device_lock);
7960                 conf->previous_raid_disks = conf->raid_disks;
7961                 md_finish_reshape(conf->mddev);
7962                 smp_wmb();
7963                 conf->reshape_progress = MaxSector;
7964                 conf->mddev->reshape_position = MaxSector;
7965                 spin_unlock_irq(&conf->device_lock);
7966                 wake_up(&conf->wait_for_overlap);
7967
7968                 /* read-ahead size must cover two whole stripes, which is
7969                  * 2 * (datadisks) * chunksize where 'n' is the number of raid devices
7970                  */
7971                 if (conf->mddev->queue) {
7972                         int data_disks = conf->raid_disks - conf->max_degraded;
7973                         int stripe = data_disks * ((conf->chunk_sectors << 9)
7974                                                    / PAGE_SIZE);
7975                         if (conf->mddev->queue->backing_dev_info->ra_pages < 2 * stripe)
7976                                 conf->mddev->queue->backing_dev_info->ra_pages = 2 * stripe;
7977                 }
7978         }
7979 }
7980
7981 /* This is called from the raid5d thread with mddev_lock held.
7982  * It makes config changes to the device.
7983  */
7984 static void raid5_finish_reshape(struct mddev *mddev)
7985 {
7986         struct r5conf *conf = mddev->private;
7987
7988         if (!test_bit(MD_RECOVERY_INTR, &mddev->recovery)) {
7989
7990                 if (mddev->delta_disks > 0) {
7991                         md_set_array_sectors(mddev, raid5_size(mddev, 0, 0));
7992                         if (mddev->queue) {
7993                                 set_capacity(mddev->gendisk, mddev->array_sectors);
7994                                 revalidate_disk(mddev->gendisk);
7995                         }
7996                 } else {
7997                         int d;
7998                         spin_lock_irq(&conf->device_lock);
7999                         mddev->degraded = raid5_calc_degraded(conf);
8000                         spin_unlock_irq(&conf->device_lock);
8001                         for (d = conf->raid_disks ;
8002                              d < conf->raid_disks - mddev->delta_disks;
8003                              d++) {
8004                                 struct md_rdev *rdev = conf->disks[d].rdev;
8005                                 if (rdev)
8006                                         clear_bit(In_sync, &rdev->flags);
8007                                 rdev = conf->disks[d].replacement;
8008                                 if (rdev)
8009                                         clear_bit(In_sync, &rdev->flags);
8010                         }
8011                 }
8012                 mddev->layout = conf->algorithm;
8013                 mddev->chunk_sectors = conf->chunk_sectors;
8014                 mddev->reshape_position = MaxSector;
8015                 mddev->delta_disks = 0;
8016                 mddev->reshape_backwards = 0;
8017         }
8018 }
8019
8020 static void raid5_quiesce(struct mddev *mddev, int state)
8021 {
8022         struct r5conf *conf = mddev->private;
8023
8024         switch(state) {
8025         case 2: /* resume for a suspend */
8026                 wake_up(&conf->wait_for_overlap);
8027                 break;
8028
8029         case 1: /* stop all writes */
8030                 lock_all_device_hash_locks_irq(conf);
8031                 /* '2' tells resync/reshape to pause so that all
8032                  * active stripes can drain
8033                  */
8034                 r5c_flush_cache(conf, INT_MAX);
8035                 conf->quiesce = 2;
8036                 wait_event_cmd(conf->wait_for_quiescent,
8037                                     atomic_read(&conf->active_stripes) == 0 &&
8038                                     atomic_read(&conf->active_aligned_reads) == 0,
8039                                     unlock_all_device_hash_locks_irq(conf),
8040                                     lock_all_device_hash_locks_irq(conf));
8041                 conf->quiesce = 1;
8042                 unlock_all_device_hash_locks_irq(conf);
8043                 /* allow reshape to continue */
8044                 wake_up(&conf->wait_for_overlap);
8045                 break;
8046
8047         case 0: /* re-enable writes */
8048                 lock_all_device_hash_locks_irq(conf);
8049                 conf->quiesce = 0;
8050                 wake_up(&conf->wait_for_quiescent);
8051                 wake_up(&conf->wait_for_overlap);
8052                 unlock_all_device_hash_locks_irq(conf);
8053                 break;
8054         }
8055         r5l_quiesce(conf->log, state);
8056 }
8057
8058 static void *raid45_takeover_raid0(struct mddev *mddev, int level)
8059 {
8060         struct r0conf *raid0_conf = mddev->private;
8061         sector_t sectors;
8062
8063         /* for raid0 takeover only one zone is supported */
8064         if (raid0_conf->nr_strip_zones > 1) {
8065                 pr_warn("md/raid:%s: cannot takeover raid0 with more than one zone.\n",
8066                         mdname(mddev));
8067                 return ERR_PTR(-EINVAL);
8068         }
8069
8070         sectors = raid0_conf->strip_zone[0].zone_end;
8071         sector_div(sectors, raid0_conf->strip_zone[0].nb_dev);
8072         mddev->dev_sectors = sectors;
8073         mddev->new_level = level;
8074         mddev->new_layout = ALGORITHM_PARITY_N;
8075         mddev->new_chunk_sectors = mddev->chunk_sectors;
8076         mddev->raid_disks += 1;
8077         mddev->delta_disks = 1;
8078         /* make sure it will be not marked as dirty */
8079         mddev->recovery_cp = MaxSector;
8080
8081         return setup_conf(mddev);
8082 }
8083
8084 static void *raid5_takeover_raid1(struct mddev *mddev)
8085 {
8086         int chunksect;
8087         void *ret;
8088
8089         if (mddev->raid_disks != 2 ||
8090             mddev->degraded > 1)
8091                 return ERR_PTR(-EINVAL);
8092
8093         /* Should check if there are write-behind devices? */
8094
8095         chunksect = 64*2; /* 64K by default */
8096
8097         /* The array must be an exact multiple of chunksize */
8098         while (chunksect && (mddev->array_sectors & (chunksect-1)))
8099                 chunksect >>= 1;
8100
8101         if ((chunksect<<9) < STRIPE_SIZE)
8102                 /* array size does not allow a suitable chunk size */
8103                 return ERR_PTR(-EINVAL);
8104
8105         mddev->new_level = 5;
8106         mddev->new_layout = ALGORITHM_LEFT_SYMMETRIC;
8107         mddev->new_chunk_sectors = chunksect;
8108
8109         ret = setup_conf(mddev);
8110         if (!IS_ERR(ret))
8111                 mddev_clear_unsupported_flags(mddev,
8112                         UNSUPPORTED_MDDEV_FLAGS);
8113         return ret;
8114 }
8115
8116 static void *raid5_takeover_raid6(struct mddev *mddev)
8117 {
8118         int new_layout;
8119
8120         switch (mddev->layout) {
8121         case ALGORITHM_LEFT_ASYMMETRIC_6:
8122                 new_layout = ALGORITHM_LEFT_ASYMMETRIC;
8123                 break;
8124         case ALGORITHM_RIGHT_ASYMMETRIC_6:
8125                 new_layout = ALGORITHM_RIGHT_ASYMMETRIC;
8126                 break;
8127         case ALGORITHM_LEFT_SYMMETRIC_6:
8128                 new_layout = ALGORITHM_LEFT_SYMMETRIC;
8129                 break;
8130         case ALGORITHM_RIGHT_SYMMETRIC_6:
8131                 new_layout = ALGORITHM_RIGHT_SYMMETRIC;
8132                 break;
8133         case ALGORITHM_PARITY_0_6:
8134                 new_layout = ALGORITHM_PARITY_0;
8135                 break;
8136         case ALGORITHM_PARITY_N:
8137                 new_layout = ALGORITHM_PARITY_N;
8138                 break;
8139         default:
8140                 return ERR_PTR(-EINVAL);
8141         }
8142         mddev->new_level = 5;
8143         mddev->new_layout = new_layout;
8144         mddev->delta_disks = -1;
8145         mddev->raid_disks -= 1;
8146         return setup_conf(mddev);
8147 }
8148
8149 static int raid5_check_reshape(struct mddev *mddev)
8150 {
8151         /* For a 2-drive array, the layout and chunk size can be changed
8152          * immediately as not restriping is needed.
8153          * For larger arrays we record the new value - after validation
8154          * to be used by a reshape pass.
8155          */
8156         struct r5conf *conf = mddev->private;
8157         int new_chunk = mddev->new_chunk_sectors;
8158
8159         if (mddev->new_layout >= 0 && !algorithm_valid_raid5(mddev->new_layout))
8160                 return -EINVAL;
8161         if (new_chunk > 0) {
8162                 if (!is_power_of_2(new_chunk))
8163                         return -EINVAL;
8164                 if (new_chunk < (PAGE_SIZE>>9))
8165                         return -EINVAL;
8166                 if (mddev->array_sectors & (new_chunk-1))
8167                         /* not factor of array size */
8168                         return -EINVAL;
8169         }
8170
8171         /* They look valid */
8172
8173         if (mddev->raid_disks == 2) {
8174                 /* can make the change immediately */
8175                 if (mddev->new_layout >= 0) {
8176                         conf->algorithm = mddev->new_layout;
8177                         mddev->layout = mddev->new_layout;
8178                 }
8179                 if (new_chunk > 0) {
8180                         conf->chunk_sectors = new_chunk ;
8181                         mddev->chunk_sectors = new_chunk;
8182                 }
8183                 set_bit(MD_SB_CHANGE_DEVS, &mddev->sb_flags);
8184                 md_wakeup_thread(mddev->thread);
8185         }
8186         return check_reshape(mddev);
8187 }
8188
8189 static int raid6_check_reshape(struct mddev *mddev)
8190 {
8191         int new_chunk = mddev->new_chunk_sectors;
8192
8193         if (mddev->new_layout >= 0 && !algorithm_valid_raid6(mddev->new_layout))
8194                 return -EINVAL;
8195         if (new_chunk > 0) {
8196                 if (!is_power_of_2(new_chunk))
8197                         return -EINVAL;
8198                 if (new_chunk < (PAGE_SIZE >> 9))
8199                         return -EINVAL;
8200                 if (mddev->array_sectors & (new_chunk-1))
8201                         /* not factor of array size */
8202                         return -EINVAL;
8203         }
8204
8205         /* They look valid */
8206         return check_reshape(mddev);
8207 }
8208
8209 static void *raid5_takeover(struct mddev *mddev)
8210 {
8211         /* raid5 can take over:
8212          *  raid0 - if there is only one strip zone - make it a raid4 layout
8213          *  raid1 - if there are two drives.  We need to know the chunk size
8214          *  raid4 - trivial - just use a raid4 layout.
8215          *  raid6 - Providing it is a *_6 layout
8216          */
8217         if (mddev->level == 0)
8218                 return raid45_takeover_raid0(mddev, 5);
8219         if (mddev->level == 1)
8220                 return raid5_takeover_raid1(mddev);
8221         if (mddev->level == 4) {
8222                 mddev->new_layout = ALGORITHM_PARITY_N;
8223                 mddev->new_level = 5;
8224                 return setup_conf(mddev);
8225         }
8226         if (mddev->level == 6)
8227                 return raid5_takeover_raid6(mddev);
8228
8229         return ERR_PTR(-EINVAL);
8230 }
8231
8232 static void *raid4_takeover(struct mddev *mddev)
8233 {
8234         /* raid4 can take over:
8235          *  raid0 - if there is only one strip zone
8236          *  raid5 - if layout is right
8237          */
8238         if (mddev->level == 0)
8239                 return raid45_takeover_raid0(mddev, 4);
8240         if (mddev->level == 5 &&
8241             mddev->layout == ALGORITHM_PARITY_N) {
8242                 mddev->new_layout = 0;
8243                 mddev->new_level = 4;
8244                 return setup_conf(mddev);
8245         }
8246         return ERR_PTR(-EINVAL);
8247 }
8248
8249 static struct md_personality raid5_personality;
8250
8251 static void *raid6_takeover(struct mddev *mddev)
8252 {
8253         /* Currently can only take over a raid5.  We map the
8254          * personality to an equivalent raid6 personality
8255          * with the Q block at the end.
8256          */
8257         int new_layout;
8258
8259         if (mddev->pers != &raid5_personality)
8260                 return ERR_PTR(-EINVAL);
8261         if (mddev->degraded > 1)
8262                 return ERR_PTR(-EINVAL);
8263         if (mddev->raid_disks > 253)
8264                 return ERR_PTR(-EINVAL);
8265         if (mddev->raid_disks < 3)
8266                 return ERR_PTR(-EINVAL);
8267
8268         switch (mddev->layout) {
8269         case ALGORITHM_LEFT_ASYMMETRIC:
8270                 new_layout = ALGORITHM_LEFT_ASYMMETRIC_6;
8271                 break;
8272         case ALGORITHM_RIGHT_ASYMMETRIC:
8273                 new_layout = ALGORITHM_RIGHT_ASYMMETRIC_6;
8274                 break;
8275         case ALGORITHM_LEFT_SYMMETRIC:
8276                 new_layout = ALGORITHM_LEFT_SYMMETRIC_6;
8277                 break;
8278         case ALGORITHM_RIGHT_SYMMETRIC:
8279                 new_layout = ALGORITHM_RIGHT_SYMMETRIC_6;
8280                 break;
8281         case ALGORITHM_PARITY_0:
8282                 new_layout = ALGORITHM_PARITY_0_6;
8283                 break;
8284         case ALGORITHM_PARITY_N:
8285                 new_layout = ALGORITHM_PARITY_N;
8286                 break;
8287         default:
8288                 return ERR_PTR(-EINVAL);
8289         }
8290         mddev->new_level = 6;
8291         mddev->new_layout = new_layout;
8292         mddev->delta_disks = 1;
8293         mddev->raid_disks += 1;
8294         return setup_conf(mddev);
8295 }
8296
8297 static int raid5_change_consistency_policy(struct mddev *mddev, const char *buf)
8298 {
8299         struct r5conf *conf;
8300         int err;
8301
8302         err = mddev_lock(mddev);
8303         if (err)
8304                 return err;
8305         conf = mddev->private;
8306         if (!conf) {
8307                 mddev_unlock(mddev);
8308                 return -ENODEV;
8309         }
8310
8311         if (strncmp(buf, "ppl", 3) == 0) {
8312                 /* ppl only works with RAID 5 */
8313                 if (!raid5_has_ppl(conf) && conf->level == 5) {
8314                         err = log_init(conf, NULL, true);
8315                         if (!err) {
8316                                 err = resize_stripes(conf, conf->pool_size);
8317                                 if (err)
8318                                         log_exit(conf);
8319                         }
8320                 } else
8321                         err = -EINVAL;
8322         } else if (strncmp(buf, "resync", 6) == 0) {
8323                 if (raid5_has_ppl(conf)) {
8324                         mddev_suspend(mddev);
8325                         log_exit(conf);
8326                         mddev_resume(mddev);
8327                         err = resize_stripes(conf, conf->pool_size);
8328                 } else if (test_bit(MD_HAS_JOURNAL, &conf->mddev->flags) &&
8329                            r5l_log_disk_error(conf)) {
8330                         bool journal_dev_exists = false;
8331                         struct md_rdev *rdev;
8332
8333                         rdev_for_each(rdev, mddev)
8334                                 if (test_bit(Journal, &rdev->flags)) {
8335                                         journal_dev_exists = true;
8336                                         break;
8337                                 }
8338
8339                         if (!journal_dev_exists) {
8340                                 mddev_suspend(mddev);
8341                                 clear_bit(MD_HAS_JOURNAL, &mddev->flags);
8342                                 mddev_resume(mddev);
8343                         } else  /* need remove journal device first */
8344                                 err = -EBUSY;
8345                 } else
8346                         err = -EINVAL;
8347         } else {
8348                 err = -EINVAL;
8349         }
8350
8351         if (!err)
8352                 md_update_sb(mddev, 1);
8353
8354         mddev_unlock(mddev);
8355
8356         return err;
8357 }
8358
8359 static struct md_personality raid6_personality =
8360 {
8361         .name           = "raid6",
8362         .level          = 6,
8363         .owner          = THIS_MODULE,
8364         .make_request   = raid5_make_request,
8365         .run            = raid5_run,
8366         .free           = raid5_free,
8367         .status         = raid5_status,
8368         .error_handler  = raid5_error,
8369         .hot_add_disk   = raid5_add_disk,
8370         .hot_remove_disk= raid5_remove_disk,
8371         .spare_active   = raid5_spare_active,
8372         .sync_request   = raid5_sync_request,
8373         .resize         = raid5_resize,
8374         .size           = raid5_size,
8375         .check_reshape  = raid6_check_reshape,
8376         .start_reshape  = raid5_start_reshape,
8377         .finish_reshape = raid5_finish_reshape,
8378         .quiesce        = raid5_quiesce,
8379         .takeover       = raid6_takeover,
8380         .congested      = raid5_congested,
8381         .change_consistency_policy = raid5_change_consistency_policy,
8382 };
8383 static struct md_personality raid5_personality =
8384 {
8385         .name           = "raid5",
8386         .level          = 5,
8387         .owner          = THIS_MODULE,
8388         .make_request   = raid5_make_request,
8389         .run            = raid5_run,
8390         .free           = raid5_free,
8391         .status         = raid5_status,
8392         .error_handler  = raid5_error,
8393         .hot_add_disk   = raid5_add_disk,
8394         .hot_remove_disk= raid5_remove_disk,
8395         .spare_active   = raid5_spare_active,
8396         .sync_request   = raid5_sync_request,
8397         .resize         = raid5_resize,
8398         .size           = raid5_size,
8399         .check_reshape  = raid5_check_reshape,
8400         .start_reshape  = raid5_start_reshape,
8401         .finish_reshape = raid5_finish_reshape,
8402         .quiesce        = raid5_quiesce,
8403         .takeover       = raid5_takeover,
8404         .congested      = raid5_congested,
8405         .change_consistency_policy = raid5_change_consistency_policy,
8406 };
8407
8408 static struct md_personality raid4_personality =
8409 {
8410         .name           = "raid4",
8411         .level          = 4,
8412         .owner          = THIS_MODULE,
8413         .make_request   = raid5_make_request,
8414         .run            = raid5_run,
8415         .free           = raid5_free,
8416         .status         = raid5_status,
8417         .error_handler  = raid5_error,
8418         .hot_add_disk   = raid5_add_disk,
8419         .hot_remove_disk= raid5_remove_disk,
8420         .spare_active   = raid5_spare_active,
8421         .sync_request   = raid5_sync_request,
8422         .resize         = raid5_resize,
8423         .size           = raid5_size,
8424         .check_reshape  = raid5_check_reshape,
8425         .start_reshape  = raid5_start_reshape,
8426         .finish_reshape = raid5_finish_reshape,
8427         .quiesce        = raid5_quiesce,
8428         .takeover       = raid4_takeover,
8429         .congested      = raid5_congested,
8430         .change_consistency_policy = raid5_change_consistency_policy,
8431 };
8432
8433 static int __init raid5_init(void)
8434 {
8435         int ret;
8436
8437         raid5_wq = alloc_workqueue("raid5wq",
8438                 WQ_UNBOUND|WQ_MEM_RECLAIM|WQ_CPU_INTENSIVE|WQ_SYSFS, 0);
8439         if (!raid5_wq)
8440                 return -ENOMEM;
8441
8442         ret = cpuhp_setup_state_multi(CPUHP_MD_RAID5_PREPARE,
8443                                       "md/raid5:prepare",
8444                                       raid456_cpu_up_prepare,
8445                                       raid456_cpu_dead);
8446         if (ret) {
8447                 destroy_workqueue(raid5_wq);
8448                 return ret;
8449         }
8450         register_md_personality(&raid6_personality);
8451         register_md_personality(&raid5_personality);
8452         register_md_personality(&raid4_personality);
8453         return 0;
8454 }
8455
8456 static void raid5_exit(void)
8457 {
8458         unregister_md_personality(&raid6_personality);
8459         unregister_md_personality(&raid5_personality);
8460         unregister_md_personality(&raid4_personality);
8461         cpuhp_remove_multi_state(CPUHP_MD_RAID5_PREPARE);
8462         destroy_workqueue(raid5_wq);
8463 }
8464
8465 module_init(raid5_init);
8466 module_exit(raid5_exit);
8467 MODULE_LICENSE("GPL");
8468 MODULE_DESCRIPTION("RAID4/5/6 (striping with parity) personality for MD");
8469 MODULE_ALIAS("md-personality-4"); /* RAID5 */
8470 MODULE_ALIAS("md-raid5");
8471 MODULE_ALIAS("md-raid4");
8472 MODULE_ALIAS("md-level-5");
8473 MODULE_ALIAS("md-level-4");
8474 MODULE_ALIAS("md-personality-8"); /* RAID6 */
8475 MODULE_ALIAS("md-raid6");
8476 MODULE_ALIAS("md-level-6");
8477
8478 /* This used to be two separate modules, they were: */
8479 MODULE_ALIAS("raid5");
8480 MODULE_ALIAS("raid6");