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 raid5_build_block(struct stripe_head *sh, int i, int previous);
 498 static void stripe_set_idx(sector_t stripe, struct r5conf *conf, int previous,
 499                             struct stripe_head *sh);
 500
 501 static void init_stripe(struct stripe_head *sh, sector_t sector, int previous)
 502 {
 503         struct r5conf *conf = sh->raid_conf;
 504         int i, seq;
 505
 506         BUG_ON(atomic_read(&sh->count) != 0);
 507         BUG_ON(test_bit(STRIPE_HANDLE, &sh->state));
 508         BUG_ON(stripe_operations_active(sh));
 509         BUG_ON(sh->batch_head);
 510
 511         pr_debug("init_stripe called, stripe %llu\n",
 512                 (unsigned long long)sector);
 513 retry:
 514         seq = read_seqcount_begin(&conf->gen_lock);
 515         sh->generation = conf->generation - previous;
 516         sh->disks = previous ? conf->previous_raid_disks : conf->raid_disks;
 517         sh->sector = sector;
 518         stripe_set_idx(sector, conf, previous, sh);
 519         sh->state = 0;
 520
 521         for (i = sh->disks; i--; ) {
 522                 struct r5dev *dev = &sh->dev[i];
 523
 524                 if (dev->toread || dev->read || dev->towrite || dev->written ||
 525                     test_bit(R5_LOCKED, &dev->flags)) {
 526                         pr_err("sector=%llx i=%d %p %p %p %p %d\n",
 527                                (unsigned long long)sh->sector, i, dev->toread,
 528                                dev->read, dev->towrite, dev->written,
 529                                test_bit(R5_LOCKED, &dev->flags));
 530                         WARN_ON(1);
 531                 }
 532                 dev->flags = 0;
 533                 raid5_build_block(sh, i, previous);
 534         }
 535         if (read_seqcount_retry(&conf->gen_lock, seq))
 536                 goto retry;
 537         sh->overwrite_disks = 0;
 538         insert_hash(conf, sh);
 539         sh->cpu = smp_processor_id();
 540         set_bit(STRIPE_BATCH_READY, &sh->state);
 541 }
 542
 543 static struct stripe_head *__find_stripe(struct r5conf *conf, sector_t sector,
 544                                          short generation)
 545 {
 546         struct stripe_head *sh;
 547
 548         pr_debug("__find_stripe, sector %llu\n", (unsigned long long)sector);
 549         hlist_for_each_entry(sh, stripe_hash(conf, sector), hash)
 550                 if (sh->sector == sector && sh->generation == generation)
 551                         return sh;
 552         pr_debug("__stripe %llu not in cache\n", (unsigned long long)sector);
 553         return NULL;
 554 }
 555
 556 /*
 557  * Need to check if array has failed when deciding whether to:
 558  *  - start an array
 559  *  - remove non-faulty devices
 560  *  - add a spare
 561  *  - allow a reshape
 562  * This determination is simple when no reshape is happening.
 563  * However if there is a reshape, we need to carefully check
 564  * both the before and after sections.
 565  * This is because some failed devices may only affect one
 566  * of the two sections, and some non-in_sync devices may
 567  * be insync in the section most affected by failed devices.
 568  */
 569 int raid5_calc_degraded(struct r5conf *conf)
 570 {
 571         int degraded, degraded2;
 572         int i;
 573
 574         rcu_read_lock();
 575         degraded = 0;
 576         for (i = 0; i < conf->previous_raid_disks; i++) {
 577                 struct md_rdev *rdev = rcu_dereference(conf->disks[i].rdev);
 578                 if (rdev && test_bit(Faulty, &rdev->flags))
 579                         rdev = rcu_dereference(conf->disks[i].replacement);
 580                 if (!rdev || test_bit(Faulty, &rdev->flags))
 581                         degraded++;
 582                 else if (test_bit(In_sync, &rdev->flags))
 583                         ;
 584                 else
 585                         /* not in-sync or faulty.
 586                          * If the reshape increases the number of devices,
 587                          * this is being recovered by the reshape, so
 588                          * this 'previous' section is not in_sync.
 589                          * If the number of devices is being reduced however,
 590                          * the device can only be part of the array if
 591                          * we are reverting a reshape, so this section will
 592                          * be in-sync.
 593                          */
 594                         if (conf->raid_disks >= conf->previous_raid_disks)
 595                                 degraded++;
 596         }
 597         rcu_read_unlock();
 598         if (conf->raid_disks == conf->previous_raid_disks)
 599                 return degraded;
 600         rcu_read_lock();
 601         degraded2 = 0;
 602         for (i = 0; i < conf->raid_disks; i++) {
 603                 struct md_rdev *rdev = rcu_dereference(conf->disks[i].rdev);
 604                 if (rdev && test_bit(Faulty, &rdev->flags))
 605                         rdev = rcu_dereference(conf->disks[i].replacement);
 606                 if (!rdev || test_bit(Faulty, &rdev->flags))
 607                         degraded2++;
 608                 else if (test_bit(In_sync, &rdev->flags))
 609                         ;
 610                 else
 611                         /* not in-sync or faulty.
 612                          * If reshape increases the number of devices, this
 613                          * section has already been recovered, else it
 614                          * almost certainly hasn't.
 615                          */
 616                         if (conf->raid_disks <= conf->previous_raid_disks)
 617                                 degraded2++;
 618         }
 619         rcu_read_unlock();
 620         if (degraded2 > degraded)
 621                 return degraded2;
 622         return degraded;
 623 }
 624
 625 static int has_failed(struct r5conf *conf)
 626 {
 627         int degraded;
 628
 629         if (conf->mddev->reshape_position == MaxSector)
 630                 return conf->mddev->degraded > conf->max_degraded;
 631
 632         degraded = raid5_calc_degraded(conf);
 633         if (degraded > conf->max_degraded)
 634                 return 1;
 635         return 0;
 636 }
 637
 638 struct stripe_head *
 639 raid5_get_active_stripe(struct r5conf *conf, sector_t sector,
 640                         int previous, int noblock, int noquiesce)
 641 {
 642         struct stripe_head *sh;
 643         int hash = stripe_hash_locks_hash(sector);
 644         int inc_empty_inactive_list_flag;
 645
 646         pr_debug("get_stripe, sector %llu\n", (unsigned long long)sector);
 647
 648         spin_lock_irq(conf->hash_locks + hash);
 649
 650         do {
 651                 wait_event_lock_irq(conf->wait_for_quiescent,
 652                                     conf->quiesce == 0 || noquiesce,
 653                                     *(conf->hash_locks + hash));
 654                 sh = __find_stripe(conf, sector, conf->generation - previous);
 655                 if (!sh) {
 656                         if (!test_bit(R5_INACTIVE_BLOCKED, &conf->cache_state)) {
 657                                 sh = get_free_stripe(conf, hash);
 658                                 if (!sh && !test_bit(R5_DID_ALLOC,
 659                                                      &conf->cache_state))
 660                                         set_bit(R5_ALLOC_MORE,
 661                                                 &conf->cache_state);
 662                         }
 663                         if (noblock && sh == NULL)
 664                                 break;
 665
 666                         r5c_check_stripe_cache_usage(conf);
 667                         if (!sh) {
 668                                 set_bit(R5_INACTIVE_BLOCKED,
 669                                         &conf->cache_state);
 670                                 r5l_wake_reclaim(conf->log, 0);
 671                                 wait_event_lock_irq(
 672                                         conf->wait_for_stripe,
 673                                         !list_empty(conf->inactive_list + hash) &&
 674                                         (atomic_read(&conf->active_stripes)
 675                                          < (conf->max_nr_stripes * 3 / 4)
 676                                          || !test_bit(R5_INACTIVE_BLOCKED,
 677                                                       &conf->cache_state)),
 678                                         *(conf->hash_locks + hash));
 679                                 clear_bit(R5_INACTIVE_BLOCKED,
 680                                           &conf->cache_state);
 681                         } else {
 682                                 init_stripe(sh, sector, previous);
 683                                 atomic_inc(&sh->count);
 684                         }
 685                 } else if (!atomic_inc_not_zero(&sh->count)) {
 686                         spin_lock(&conf->device_lock);
 687                         if (!atomic_read(&sh->count)) {
 688                                 if (!test_bit(STRIPE_HANDLE, &sh->state))
 689                                         atomic_inc(&conf->active_stripes);
 690                                 BUG_ON(list_empty(&sh->lru) &&
 691                                        !test_bit(STRIPE_EXPANDING, &sh->state));
 692                                 inc_empty_inactive_list_flag = 0;
 693                                 if (!list_empty(conf->inactive_list + hash))
 694                                         inc_empty_inactive_list_flag = 1;
 695                                 list_del_init(&sh->lru);
 696                                 if (list_empty(conf->inactive_list + hash) && inc_empty_inactive_list_flag)
 697                                         atomic_inc(&conf->empty_inactive_list_nr);
 698                                 if (sh->group) {
 699                                         sh->group->stripes_cnt--;
 700                                         sh->group = NULL;
 701                                 }
 702                         }
 703                         atomic_inc(&sh->count);
 704                         spin_unlock(&conf->device_lock);
 705                 }
 706         } while (sh == NULL);
 707
 708         spin_unlock_irq(conf->hash_locks + hash);
 709         return sh;
 710 }
 711
 712 static bool is_full_stripe_write(struct stripe_head *sh)
 713 {
 714         BUG_ON(sh->overwrite_disks > (sh->disks - sh->raid_conf->max_degraded));
 715         return sh->overwrite_disks == (sh->disks - sh->raid_conf->max_degraded);
 716 }
 717
 718 static void lock_two_stripes(struct stripe_head *sh1, struct stripe_head *sh2)
 719 {
 720         if (sh1 > sh2) {
 721                 spin_lock_irq(&sh2->stripe_lock);
 722                 spin_lock_nested(&sh1->stripe_lock, 1);
 723         } else {
 724                 spin_lock_irq(&sh1->stripe_lock);
 725                 spin_lock_nested(&sh2->stripe_lock, 1);
 726         }
 727 }
 728
 729 static void unlock_two_stripes(struct stripe_head *sh1, struct stripe_head *sh2)
 730 {
 731         spin_unlock(&sh1->stripe_lock);
 732         spin_unlock_irq(&sh2->stripe_lock);
 733 }
 734
 735 /* Only freshly new full stripe normal write stripe can be added to a batch list */
 736 static bool stripe_can_batch(struct stripe_head *sh)
 737 {
 738         struct r5conf *conf = sh->raid_conf;
 739
 740         if (conf->log || raid5_has_ppl(conf))
 741                 return false;
 742         return test_bit(STRIPE_BATCH_READY, &sh->state) &&
 743                 !test_bit(STRIPE_BITMAP_PENDING, &sh->state) &&
 744                 is_full_stripe_write(sh);
 745 }
 746
 747 /* we only do back search */
 748 static void stripe_add_to_batch_list(struct r5conf *conf, struct stripe_head *sh)
 749 {
 750         struct stripe_head *head;
 751         sector_t head_sector, tmp_sec;
 752         int hash;
 753         int dd_idx;
 754         int inc_empty_inactive_list_flag;
 755
 756         /* Don't cross chunks, so stripe pd_idx/qd_idx is the same */
 757         tmp_sec = sh->sector;
 758         if (!sector_div(tmp_sec, conf->chunk_sectors))
 759                 return;
 760         head_sector = sh->sector - STRIPE_SECTORS;
 761
 762         hash = stripe_hash_locks_hash(head_sector);
 763         spin_lock_irq(conf->hash_locks + hash);
 764         head = __find_stripe(conf, head_sector, conf->generation);
 765         if (head && !atomic_inc_not_zero(&head->count)) {
 766                 spin_lock(&conf->device_lock);
 767                 if (!atomic_read(&head->count)) {
 768                         if (!test_bit(STRIPE_HANDLE, &head->state))
 769                                 atomic_inc(&conf->active_stripes);
 770                         BUG_ON(list_empty(&head->lru) &&
 771                                !test_bit(STRIPE_EXPANDING, &head->state));
 772                         inc_empty_inactive_list_flag = 0;
 773                         if (!list_empty(conf->inactive_list + hash))
 774                                 inc_empty_inactive_list_flag = 1;
 775                         list_del_init(&head->lru);
 776                         if (list_empty(conf->inactive_list + hash) && inc_empty_inactive_list_flag)
 777                                 atomic_inc(&conf->empty_inactive_list_nr);
 778                         if (head->group) {
 779                                 head->group->stripes_cnt--;
 780                                 head->group = NULL;
 781                         }
 782                 }
 783                 atomic_inc(&head->count);
 784                 spin_unlock(&conf->device_lock);
 785         }
 786         spin_unlock_irq(conf->hash_locks + hash);
 787
 788         if (!head)
 789                 return;
 790         if (!stripe_can_batch(head))
 791                 goto out;
 792
 793         lock_two_stripes(head, sh);
 794         /* clear_batch_ready clear the flag */
 795         if (!stripe_can_batch(head) || !stripe_can_batch(sh))
 796                 goto unlock_out;
 797
 798         if (sh->batch_head)
 799                 goto unlock_out;
 800
 801         dd_idx = 0;
 802         while (dd_idx == sh->pd_idx || dd_idx == sh->qd_idx)
 803                 dd_idx++;
 804         if (head->dev[dd_idx].towrite->bi_opf != sh->dev[dd_idx].towrite->bi_opf ||
 805             bio_op(head->dev[dd_idx].towrite) != bio_op(sh->dev[dd_idx].towrite))
 806                 goto unlock_out;
 807
 808         if (head->batch_head) {
 809                 spin_lock(&head->batch_head->batch_lock);
 810                 /* This batch list is already running */
 811                 if (!stripe_can_batch(head)) {
 812                         spin_unlock(&head->batch_head->batch_lock);
 813                         goto unlock_out;
 814                 }
 815
 816                 /*
 817                  * at this point, head's BATCH_READY could be cleared, but we
 818                  * can still add the stripe to batch list
 819                  */
 820                 list_add(&sh->batch_list, &head->batch_list);
 821                 spin_unlock(&head->batch_head->batch_lock);
 822
 823                 sh->batch_head = head->batch_head;
 824         } else {
 825                 head->batch_head = head;
 826                 sh->batch_head = head->batch_head;
 827                 spin_lock(&head->batch_lock);
 828                 list_add_tail(&sh->batch_list, &head->batch_list);
 829                 spin_unlock(&head->batch_lock);
 830         }
 831
 832         if (test_and_clear_bit(STRIPE_PREREAD_ACTIVE, &sh->state))
 833                 if (atomic_dec_return(&conf->preread_active_stripes)
 834                     < IO_THRESHOLD)
 835                         md_wakeup_thread(conf->mddev->thread);
 836
 837         if (test_and_clear_bit(STRIPE_BIT_DELAY, &sh->state)) {
 838                 int seq = sh->bm_seq;
 839                 if (test_bit(STRIPE_BIT_DELAY, &sh->batch_head->state) &&
 840                     sh->batch_head->bm_seq > seq)
 841                         seq = sh->batch_head->bm_seq;
 842                 set_bit(STRIPE_BIT_DELAY, &sh->batch_head->state);
 843                 sh->batch_head->bm_seq = seq;
 844         }
 845
 846         atomic_inc(&sh->count);
 847 unlock_out:
 848         unlock_two_stripes(head, sh);
 849 out:
 850         raid5_release_stripe(head);
 851 }
 852
 853 /* Determine if 'data_offset' or 'new_data_offset' should be used
 854  * in this stripe_head.
 855  */
 856 static int use_new_offset(struct r5conf *conf, struct stripe_head *sh)
 857 {
 858         sector_t progress = conf->reshape_progress;
 859         /* Need a memory barrier to make sure we see the value
 860          * of conf->generation, or ->data_offset that was set before
 861          * reshape_progress was updated.
 862          */
 863         smp_rmb();
 864         if (progress == MaxSector)
 865                 return 0;
 866         if (sh->generation == conf->generation - 1)
 867                 return 0;
 868         /* We are in a reshape, and this is a new-generation stripe,
 869          * so use new_data_offset.
 870          */
 871         return 1;
 872 }
 873
 874 static void dispatch_bio_list(struct bio_list *tmp)
 875 {
 876         struct bio *bio;
 877
 878         while ((bio = bio_list_pop(tmp)))
 879                 generic_make_request(bio);
 880 }
 881
 882 static int cmp_stripe(void *priv, struct list_head *a, struct list_head *b)
 883 {
 884         const struct r5pending_data *da = list_entry(a,
 885                                 struct r5pending_data, sibling);
 886         const struct r5pending_data *db = list_entry(b,
 887                                 struct r5pending_data, sibling);
 888         if (da->sector > db->sector)
 889                 return 1;
 890         if (da->sector < db->sector)
 891                 return -1;
 892         return 0;
 893 }
 894
 895 static void dispatch_defer_bios(struct r5conf *conf, int target,
 896                                 struct bio_list *list)
 897 {
 898         struct r5pending_data *data;
 899         struct list_head *first, *next = NULL;
 900         int cnt = 0;
 901
 902         if (conf->pending_data_cnt == 0)
 903                 return;
 904
 905         list_sort(NULL, &conf->pending_list, cmp_stripe);
 906
 907         first = conf->pending_list.next;
 908
 909         /* temporarily move the head */
 910         if (conf->next_pending_data)
 911                 list_move_tail(&conf->pending_list,
 912                                 &conf->next_pending_data->sibling);
 913
 914         while (!list_empty(&conf->pending_list)) {
 915                 data = list_first_entry(&conf->pending_list,
 916                         struct r5pending_data, sibling);
 917                 if (&data->sibling == first)
 918                         first = data->sibling.next;
 919                 next = data->sibling.next;
 920
 921                 bio_list_merge(list, &data->bios);
 922                 list_move(&data->sibling, &conf->free_list);
 923                 cnt++;
 924                 if (cnt >= target)
 925                         break;
 926         }
 927         conf->pending_data_cnt -= cnt;
 928         BUG_ON(conf->pending_data_cnt < 0 || cnt < target);
 929
 930         if (next != &conf->pending_list)
 931                 conf->next_pending_data = list_entry(next,
 932                                 struct r5pending_data, sibling);
 933         else
 934                 conf->next_pending_data = NULL;
 935         /* list isn't empty */
 936         if (first != &conf->pending_list)
 937                 list_move_tail(&conf->pending_list, first);
 938 }
 939
 940 static void flush_deferred_bios(struct r5conf *conf)
 941 {
 942         struct bio_list tmp = BIO_EMPTY_LIST;
 943
 944         if (conf->pending_data_cnt == 0)
 945                 return;
 946
 947         spin_lock(&conf->pending_bios_lock);
 948         dispatch_defer_bios(conf, conf->pending_data_cnt, &tmp);
 949         BUG_ON(conf->pending_data_cnt != 0);
 950         spin_unlock(&conf->pending_bios_lock);
 951
 952         dispatch_bio_list(&tmp);
 953 }
 954
 955 static void defer_issue_bios(struct r5conf *conf, sector_t sector,
 956                                 struct bio_list *bios)
 957 {
 958         struct bio_list tmp = BIO_EMPTY_LIST;
 959         struct r5pending_data *ent;
 960
 961         spin_lock(&conf->pending_bios_lock);
 962         ent = list_first_entry(&conf->free_list, struct r5pending_data,
 963                                                         sibling);
 964         list_move_tail(&ent->sibling, &conf->pending_list);
 965         ent->sector = sector;
 966         bio_list_init(&ent->bios);
 967         bio_list_merge(&ent->bios, bios);
 968         conf->pending_data_cnt++;
 969         if (conf->pending_data_cnt >= PENDING_IO_MAX)
 970                 dispatch_defer_bios(conf, PENDING_IO_ONE_FLUSH, &tmp);
 971
 972         spin_unlock(&conf->pending_bios_lock);
 973
 974         dispatch_bio_list(&tmp);
 975 }
 976
 977 static void
 978 raid5_end_read_request(struct bio *bi);
 979 static void
 980 raid5_end_write_request(struct bio *bi);
 981
 982 static void ops_run_io(struct stripe_head *sh, struct stripe_head_state *s)
 983 {
 984         struct r5conf *conf = sh->raid_conf;
 985         int i, disks = sh->disks;
 986         struct stripe_head *head_sh = sh;
 987         struct bio_list pending_bios = BIO_EMPTY_LIST;
 988         bool should_defer;
 989
 990         might_sleep();
 991
 992         if (log_stripe(sh, s) == 0)
 993                 return;
 994
 995         should_defer = conf->batch_bio_dispatch && conf->group_cnt;
 996
 997         for (i = disks; i--; ) {
 998                 int op, op_flags = 0;
 999                 int replace_only = 0;
1000                 struct bio *bi, *rbi;
1001                 struct md_rdev *rdev, *rrdev = NULL;
1002
1003                 sh = head_sh;
1004                 if (test_and_clear_bit(R5_Wantwrite, &sh->dev[i].flags)) {
1005                         op = REQ_OP_WRITE;
1006                         if (test_and_clear_bit(R5_WantFUA, &sh->dev[i].flags))
1007                                 op_flags = REQ_FUA;
1008                         if (test_bit(R5_Discard, &sh->dev[i].flags))
1009                                 op = REQ_OP_DISCARD;
1010                 } else if (test_and_clear_bit(R5_Wantread, &sh->dev[i].flags))
1011                         op = REQ_OP_READ;
1012                 else if (test_and_clear_bit(R5_WantReplace,
1013                                             &sh->dev[i].flags)) {
1014                         op = REQ_OP_WRITE;
1015                         replace_only = 1;
1016                 } else
1017                         continue;
1018                 if (test_and_clear_bit(R5_SyncIO, &sh->dev[i].flags))
1019                         op_flags |= REQ_SYNC;
1020
1021 again:
1022                 bi = &sh->dev[i].req;
1023                 rbi = &sh->dev[i].rreq; /* For writing to replacement */
1024
1025                 rcu_read_lock();
1026                 rrdev = rcu_dereference(conf->disks[i].replacement);
1027                 smp_mb(); /* Ensure that if rrdev is NULL, rdev won't be */
1028                 rdev = rcu_dereference(conf->disks[i].rdev);
1029                 if (!rdev) {
1030                         rdev = rrdev;
1031                         rrdev = NULL;
1032                 }
1033                 if (op_is_write(op)) {
1034                         if (replace_only)
1035                                 rdev = NULL;
1036                         if (rdev == rrdev)
1037                                 /* We raced and saw duplicates */
1038                                 rrdev = NULL;
1039                 } else {
1040                         if (test_bit(R5_ReadRepl, &head_sh->dev[i].flags) && rrdev)
1041                                 rdev = rrdev;
1042                         rrdev = NULL;
1043                 }
1044
1045                 if (rdev && test_bit(Faulty, &rdev->flags))
1046                         rdev = NULL;
1047                 if (rdev)
1048                         atomic_inc(&rdev->nr_pending);
1049                 if (rrdev && test_bit(Faulty, &rrdev->flags))
1050                         rrdev = NULL;
1051                 if (rrdev)
1052                         atomic_inc(&rrdev->nr_pending);
1053                 rcu_read_unlock();
1054
1055                 /* We have already checked bad blocks for reads.  Now
1056                  * need to check for writes.  We never accept write errors
1057                  * on the replacement, so we don't to check rrdev.
1058                  */
1059                 while (op_is_write(op) && rdev &&
1060                        test_bit(WriteErrorSeen, &rdev->flags)) {
1061                         sector_t first_bad;
1062                         int bad_sectors;
1063                         int bad = is_badblock(rdev, sh->sector, STRIPE_SECTORS,
1064                                               &first_bad, &bad_sectors);
1065                         if (!bad)
1066                                 break;
1067
1068                         if (bad < 0) {
1069                                 set_bit(BlockedBadBlocks, &rdev->flags);
1070                                 if (!conf->mddev->external &&
1071                                     conf->mddev->sb_flags) {
1072                                         /* It is very unlikely, but we might
1073                                          * still need to write out the
1074                                          * bad block log - better give it
1075                                          * a chance*/
1076                                         md_check_recovery(conf->mddev);
1077                                 }
1078                                 /*
1079                                  * Because md_wait_for_blocked_rdev
1080                                  * will dec nr_pending, we must
1081                                  * increment it first.
1082                                  */
1083                                 atomic_inc(&rdev->nr_pending);
1084                                 md_wait_for_blocked_rdev(rdev, conf->mddev);
1085                         } else {
1086                                 /* Acknowledged bad block - skip the write */
1087                                 rdev_dec_pending(rdev, conf->mddev);
1088                                 rdev = NULL;
1089                         }
1090                 }
1091
1092                 if (rdev) {
1093                         if (s->syncing || s->expanding || s->expanded
1094                             || s->replacing)
1095                                 md_sync_acct(rdev->bdev, STRIPE_SECTORS);
1096
1097                         set_bit(STRIPE_IO_STARTED, &sh->state);
1098
1099                         bio_set_dev(bi, rdev->bdev);
1100                         bio_set_op_attrs(bi, op, op_flags);
1101                         bi->bi_end_io = op_is_write(op)
1102                                 ? raid5_end_write_request
1103                                 : raid5_end_read_request;
1104                         bi->bi_private = sh;
1105
1106                         pr_debug("%s: for %llu schedule op %d on disc %d\n",
1107                                 __func__, (unsigned long long)sh->sector,
1108                                 bi->bi_opf, i);
1109                         atomic_inc(&sh->count);
1110                         if (sh != head_sh)
1111                                 atomic_inc(&head_sh->count);
1112                         if (use_new_offset(conf, sh))
1113                                 bi->bi_iter.bi_sector = (sh->sector
1114                                                  + rdev->new_data_offset);
1115                         else
1116                                 bi->bi_iter.bi_sector = (sh->sector
1117                                                  + rdev->data_offset);
1118                         if (test_bit(R5_ReadNoMerge, &head_sh->dev[i].flags))
1119                                 bi->bi_opf |= REQ_NOMERGE;
1120
1121                         if (test_bit(R5_SkipCopy, &sh->dev[i].flags))
1122                                 WARN_ON(test_bit(R5_UPTODATE, &sh->dev[i].flags));
1123
1124                         if (!op_is_write(op) &&
1125                             test_bit(R5_InJournal, &sh->dev[i].flags))
1126                                 /*
1127                                  * issuing read for a page in journal, this
1128                                  * must be preparing for prexor in rmw; read
1129                                  * the data into orig_page
1130                                  */
1131                                 sh->dev[i].vec.bv_page = sh->dev[i].orig_page;
1132                         else
1133                                 sh->dev[i].vec.bv_page = sh->dev[i].page;
1134                         bi->bi_vcnt = 1;
1135                         bi->bi_io_vec[0].bv_len = STRIPE_SIZE;
1136                         bi->bi_io_vec[0].bv_offset = 0;
1137                         bi->bi_iter.bi_size = STRIPE_SIZE;
1138                         /*
1139                          * If this is discard request, set bi_vcnt 0. We don't
1140                          * want to confuse SCSI because SCSI will replace payload
1141                          */
1142                         if (op == REQ_OP_DISCARD)
1143                                 bi->bi_vcnt = 0;
1144                         if (rrdev)
1145                                 set_bit(R5_DOUBLE_LOCKED, &sh->dev[i].flags);
1146
1147                         if (conf->mddev->gendisk)
1148                                 trace_block_bio_remap(bi->bi_disk->queue,
1149                                                       bi, disk_devt(conf->mddev->gendisk),
1150                                                       sh->dev[i].sector);
1151                         if (should_defer && op_is_write(op))
1152                                 bio_list_add(&pending_bios, bi);
1153                         else
1154                                 generic_make_request(bi);
1155                 }
1156                 if (rrdev) {
1157                         if (s->syncing || s->expanding || s->expanded
1158                             || s->replacing)
1159                                 md_sync_acct(rrdev->bdev, STRIPE_SECTORS);
1160
1161                         set_bit(STRIPE_IO_STARTED, &sh->state);
1162
1163                         bio_set_dev(rbi, rrdev->bdev);
1164                         bio_set_op_attrs(rbi, op, op_flags);
1165                         BUG_ON(!op_is_write(op));
1166                         rbi->bi_end_io = raid5_end_write_request;
1167                         rbi->bi_private = sh;
1168
1169                         pr_debug("%s: for %llu schedule op %d on "
1170                                  "replacement disc %d\n",
1171                                 __func__, (unsigned long long)sh->sector,
1172                                 rbi->bi_opf, i);
1173                         atomic_inc(&sh->count);
1174                         if (sh != head_sh)
1175                                 atomic_inc(&head_sh->count);
1176                         if (use_new_offset(conf, sh))
1177                                 rbi->bi_iter.bi_sector = (sh->sector
1178                                                   + rrdev->new_data_offset);
1179                         else
1180                                 rbi->bi_iter.bi_sector = (sh->sector
1181                                                   + rrdev->data_offset);
1182                         if (test_bit(R5_SkipCopy, &sh->dev[i].flags))
1183                                 WARN_ON(test_bit(R5_UPTODATE, &sh->dev[i].flags));
1184                         sh->dev[i].rvec.bv_page = sh->dev[i].page;
1185                         rbi->bi_vcnt = 1;
1186                         rbi->bi_io_vec[0].bv_len = STRIPE_SIZE;
1187                         rbi->bi_io_vec[0].bv_offset = 0;
1188                         rbi->bi_iter.bi_size = STRIPE_SIZE;
1189                         /*
1190                          * If this is discard request, set bi_vcnt 0. We don't
1191                          * want to confuse SCSI because SCSI will replace payload
1192                          */
1193                         if (op == REQ_OP_DISCARD)
1194                                 rbi->bi_vcnt = 0;
1195                         if (conf->mddev->gendisk)
1196                                 trace_block_bio_remap(rbi->bi_disk->queue,
1197                                                       rbi, disk_devt(conf->mddev->gendisk),
1198                                                       sh->dev[i].sector);
1199                         if (should_defer && op_is_write(op))
1200                                 bio_list_add(&pending_bios, rbi);
1201                         else
1202                                 generic_make_request(rbi);
1203                 }
1204                 if (!rdev && !rrdev) {
1205                         if (op_is_write(op))
1206                                 set_bit(STRIPE_DEGRADED, &sh->state);
1207                         pr_debug("skip op %d on disc %d for sector %llu\n",
1208                                 bi->bi_opf, i, (unsigned long long)sh->sector);
1209                         clear_bit(R5_LOCKED, &sh->dev[i].flags);
1210                         set_bit(STRIPE_HANDLE, &sh->state);
1211                 }
1212
1213                 if (!head_sh->batch_head)
1214                         continue;
1215                 sh = list_first_entry(&sh->batch_list, struct stripe_head,
1216                                       batch_list);
1217                 if (sh != head_sh)
1218                         goto again;
1219         }
1220
1221         if (should_defer && !bio_list_empty(&pending_bios))
1222                 defer_issue_bios(conf, head_sh->sector, &pending_bios);
1223 }
1224
1225 static struct dma_async_tx_descriptor *
1226 async_copy_data(int frombio, struct bio *bio, struct page **page,
1227         sector_t sector, struct dma_async_tx_descriptor *tx,
1228         struct stripe_head *sh, int no_skipcopy)
1229 {
1230         struct bio_vec bvl;
1231         struct bvec_iter iter;
1232         struct page *bio_page;
1233         int page_offset;
1234         struct async_submit_ctl submit;
1235         enum async_tx_flags flags = 0;
1236
1237         if (bio->bi_iter.bi_sector >= sector)
1238                 page_offset = (signed)(bio->bi_iter.bi_sector - sector) * 512;
1239         else
1240                 page_offset = (signed)(sector - bio->bi_iter.bi_sector) * -512;
1241
1242         if (frombio)
1243                 flags |= ASYNC_TX_FENCE;
1244         init_async_submit(&submit, flags, tx, NULL, NULL, NULL);
1245
1246         bio_for_each_segment(bvl, bio, iter) {
1247                 int len = bvl.bv_len;
1248                 int clen;
1249                 int b_offset = 0;
1250
1251                 if (page_offset < 0) {
1252                         b_offset = -page_offset;
1253                         page_offset += b_offset;
1254                         len -= b_offset;
1255                 }
1256
1257                 if (len > 0 && page_offset + len > STRIPE_SIZE)
1258                         clen = STRIPE_SIZE - page_offset;
1259                 else
1260                         clen = len;
1261
1262                 if (clen > 0) {
1263                         b_offset += bvl.bv_offset;
1264                         bio_page = bvl.bv_page;
1265                         if (frombio) {
1266                                 if (sh->raid_conf->skip_copy &&
1267                                     b_offset == 0 && page_offset == 0 &&
1268                                     clen == STRIPE_SIZE &&
1269                                     !no_skipcopy)
1270                                         *page = bio_page;
1271                                 else
1272                                         tx = async_memcpy(*page, bio_page, page_offset,
1273                                                   b_offset, clen, &submit);
1274                         } else
1275                                 tx = async_memcpy(bio_page, *page, b_offset,
1276                                                   page_offset, clen, &submit);
1277                 }
1278                 /* chain the operations */
1279                 submit.depend_tx = tx;
1280
1281                 if (clen < len) /* hit end of page */
1282                         break;
1283                 page_offset +=  len;
1284         }
1285
1286         return tx;
1287 }
1288
1289 static void ops_complete_biofill(void *stripe_head_ref)
1290 {
1291         struct stripe_head *sh = stripe_head_ref;
1292         int i;
1293
1294         pr_debug("%s: stripe %llu\n", __func__,
1295                 (unsigned long long)sh->sector);
1296
1297         /* clear completed biofills */
1298         for (i = sh->disks; i--; ) {
1299                 struct r5dev *dev = &sh->dev[i];
1300
1301                 /* acknowledge completion of a biofill operation */
1302                 /* and check if we need to reply to a read request,
1303                  * new R5_Wantfill requests are held off until
1304                  * !STRIPE_BIOFILL_RUN
1305                  */
1306                 if (test_and_clear_bit(R5_Wantfill, &dev->flags)) {
1307                         struct bio *rbi, *rbi2;
1308
1309                         BUG_ON(!dev->read);
1310                         rbi = dev->read;
1311                         dev->read = NULL;
1312                         while (rbi && rbi->bi_iter.bi_sector <
1313                                 dev->sector + STRIPE_SECTORS) {
1314                                 rbi2 = r5_next_bio(rbi, dev->sector);
1315                                 bio_endio(rbi);
1316                                 rbi = rbi2;
1317                         }
1318                 }
1319         }
1320         clear_bit(STRIPE_BIOFILL_RUN, &sh->state);
1321
1322         set_bit(STRIPE_HANDLE, &sh->state);
1323         raid5_release_stripe(sh);
1324 }
1325
1326 static void ops_run_biofill(struct stripe_head *sh)
1327 {
1328         struct dma_async_tx_descriptor *tx = NULL;
1329         struct async_submit_ctl submit;
1330         int i;
1331
1332         BUG_ON(sh->batch_head);
1333         pr_debug("%s: stripe %llu\n", __func__,
1334                 (unsigned long long)sh->sector);
1335
1336         for (i = sh->disks; i--; ) {
1337                 struct r5dev *dev = &sh->dev[i];
1338                 if (test_bit(R5_Wantfill, &dev->flags)) {
1339                         struct bio *rbi;
1340                         spin_lock_irq(&sh->stripe_lock);
1341                         dev->read = rbi = dev->toread;
1342                         dev->toread = NULL;
1343                         spin_unlock_irq(&sh->stripe_lock);
1344                         while (rbi && rbi->bi_iter.bi_sector <
1345                                 dev->sector + STRIPE_SECTORS) {
1346                                 tx = async_copy_data(0, rbi, &dev->page,
1347                                                      dev->sector, tx, sh, 0);
1348                                 rbi = r5_next_bio(rbi, dev->sector);
1349                         }
1350                 }
1351         }
1352
1353         atomic_inc(&sh->count);
1354         init_async_submit(&submit, ASYNC_TX_ACK, tx, ops_complete_biofill, sh, NULL);
1355         async_trigger_callback(&submit);
1356 }
1357
1358 static void mark_target_uptodate(struct stripe_head *sh, int target)
1359 {
1360         struct r5dev *tgt;
1361
1362         if (target < 0)
1363                 return;
1364
1365         tgt = &sh->dev[target];
1366         set_bit(R5_UPTODATE, &tgt->flags);
1367         BUG_ON(!test_bit(R5_Wantcompute, &tgt->flags));
1368         clear_bit(R5_Wantcompute, &tgt->flags);
1369 }
1370
1371 static void ops_complete_compute(void *stripe_head_ref)
1372 {
1373         struct stripe_head *sh = stripe_head_ref;
1374
1375         pr_debug("%s: stripe %llu\n", __func__,
1376                 (unsigned long long)sh->sector);
1377
1378         /* mark the computed target(s) as uptodate */
1379         mark_target_uptodate(sh, sh->ops.target);
1380         mark_target_uptodate(sh, sh->ops.target2);
1381
1382         clear_bit(STRIPE_COMPUTE_RUN, &sh->state);
1383         if (sh->check_state == check_state_compute_run)
1384                 sh->check_state = check_state_compute_result;
1385         set_bit(STRIPE_HANDLE, &sh->state);
1386         raid5_release_stripe(sh);
1387 }
1388
1389 /* return a pointer to the address conversion region of the scribble buffer */
1390 static addr_conv_t *to_addr_conv(struct stripe_head *sh,
1391                                  struct raid5_percpu *percpu, int i)
1392 {
1393         void *addr;
1394
1395         addr = flex_array_get(percpu->scribble, i);
1396         return addr + sizeof(struct page *) * (sh->disks + 2);
1397 }
1398
1399 /* return a pointer to the address conversion region of the scribble buffer */
1400 static struct page **to_addr_page(struct raid5_percpu *percpu, int i)
1401 {
1402         void *addr;
1403
1404         addr = flex_array_get(percpu->scribble, i);
1405         return addr;
1406 }
1407
1408 static struct dma_async_tx_descriptor *
1409 ops_run_compute5(struct stripe_head *sh, struct raid5_percpu *percpu)
1410 {
1411         int disks = sh->disks;
1412         struct page **xor_srcs = to_addr_page(percpu, 0);
1413         int target = sh->ops.target;
1414         struct r5dev *tgt = &sh->dev[target];
1415         struct page *xor_dest = tgt->page;
1416         int count = 0;
1417         struct dma_async_tx_descriptor *tx;
1418         struct async_submit_ctl submit;
1419         int i;
1420
1421         BUG_ON(sh->batch_head);
1422
1423         pr_debug("%s: stripe %llu block: %d\n",
1424                 __func__, (unsigned long long)sh->sector, target);
1425         BUG_ON(!test_bit(R5_Wantcompute, &tgt->flags));
1426
1427         for (i = disks; i--; )
1428                 if (i != target)
1429                         xor_srcs[count++] = sh->dev[i].page;
1430
1431         atomic_inc(&sh->count);
1432
1433         init_async_submit(&submit, ASYNC_TX_FENCE|ASYNC_TX_XOR_ZERO_DST, NULL,
1434                           ops_complete_compute, sh, to_addr_conv(sh, percpu, 0));
1435         if (unlikely(count == 1))
1436                 tx = async_memcpy(xor_dest, xor_srcs[0], 0, 0, STRIPE_SIZE, &submit);
1437         else
1438                 tx = async_xor(xor_dest, xor_srcs, 0, count, STRIPE_SIZE, &submit);
1439
1440         return tx;
1441 }
1442
1443 /* set_syndrome_sources - populate source buffers for gen_syndrome
1444  * @srcs - (struct page *) array of size sh->disks
1445  * @sh - stripe_head to parse
1446  *
1447  * Populates srcs in proper layout order for the stripe and returns the
1448  * 'count' of sources to be used in a call to async_gen_syndrome.  The P
1449  * destination buffer is recorded in srcs[count] and the Q destination
1450  * is recorded in srcs[count+1]].
1451  */
1452 static int set_syndrome_sources(struct page **srcs,
1453                                 struct stripe_head *sh,
1454                                 int srctype)
1455 {
1456         int disks = sh->disks;
1457         int syndrome_disks = sh->ddf_layout ? disks : (disks - 2);
1458         int d0_idx = raid6_d0(sh);
1459         int count;
1460         int i;
1461
1462         for (i = 0; i < disks; i++)
1463                 srcs[i] = NULL;
1464
1465         count = 0;
1466         i = d0_idx;
1467         do {
1468                 int slot = raid6_idx_to_slot(i, sh, &count, syndrome_disks);
1469                 struct r5dev *dev = &sh->dev[i];
1470
1471                 if (i == sh->qd_idx || i == sh->pd_idx ||
1472                     (srctype == SYNDROME_SRC_ALL) ||
1473                     (srctype == SYNDROME_SRC_WANT_DRAIN &&
1474                      (test_bit(R5_Wantdrain, &dev->flags) ||
1475                       test_bit(R5_InJournal, &dev->flags))) ||
1476                     (srctype == SYNDROME_SRC_WRITTEN &&
1477                      (dev->written ||
1478                       test_bit(R5_InJournal, &dev->flags)))) {
1479                         if (test_bit(R5_InJournal, &dev->flags))
1480                                 srcs[slot] = sh->dev[i].orig_page;
1481                         else
1482                                 srcs[slot] = sh->dev[i].page;
1483                 }
1484                 i = raid6_next_disk(i, disks);
1485         } while (i != d0_idx);
1486
1487         return syndrome_disks;
1488 }
1489
1490 static struct dma_async_tx_descriptor *
1491 ops_run_compute6_1(struct stripe_head *sh, struct raid5_percpu *percpu)
1492 {
1493         int disks = sh->disks;
1494         struct page **blocks = to_addr_page(percpu, 0);
1495         int target;
1496         int qd_idx = sh->qd_idx;
1497         struct dma_async_tx_descriptor *tx;
1498         struct async_submit_ctl submit;
1499         struct r5dev *tgt;
1500         struct page *dest;
1501         int i;
1502         int count;
1503
1504         BUG_ON(sh->batch_head);
1505         if (sh->ops.target < 0)
1506                 target = sh->ops.target2;
1507         else if (sh->ops.target2 < 0)
1508                 target = sh->ops.target;
1509         else
1510                 /* we should only have one valid target */
1511                 BUG();
1512         BUG_ON(target < 0);
1513         pr_debug("%s: stripe %llu block: %d\n",
1514                 __func__, (unsigned long long)sh->sector, target);
1515
1516         tgt = &sh->dev[target];
1517         BUG_ON(!test_bit(R5_Wantcompute, &tgt->flags));
1518         dest = tgt->page;
1519
1520         atomic_inc(&sh->count);
1521
1522         if (target == qd_idx) {
1523                 count = set_syndrome_sources(blocks, sh, SYNDROME_SRC_ALL);
1524                 blocks[count] = NULL; /* regenerating p is not necessary */
1525                 BUG_ON(blocks[count+1] != dest); /* q should already be set */
1526                 init_async_submit(&submit, ASYNC_TX_FENCE, NULL,
1527                                   ops_complete_compute, sh,
1528                                   to_addr_conv(sh, percpu, 0));
1529                 tx = async_gen_syndrome(blocks, 0, count+2, STRIPE_SIZE, &submit);
1530         } else {
1531                 /* Compute any data- or p-drive using XOR */
1532                 count = 0;
1533                 for (i = disks; i-- ; ) {
1534                         if (i == target || i == qd_idx)
1535                                 continue;
1536                         blocks[count++] = sh->dev[i].page;
1537                 }
1538
1539                 init_async_submit(&submit, ASYNC_TX_FENCE|ASYNC_TX_XOR_ZERO_DST,
1540                                   NULL, ops_complete_compute, sh,
1541                                   to_addr_conv(sh, percpu, 0));
1542                 tx = async_xor(dest, blocks, 0, count, STRIPE_SIZE, &submit);
1543         }
1544
1545         return tx;
1546 }
1547
1548 static struct dma_async_tx_descriptor *
1549 ops_run_compute6_2(struct stripe_head *sh, struct raid5_percpu *percpu)
1550 {
1551         int i, count, disks = sh->disks;
1552         int syndrome_disks = sh->ddf_layout ? disks : disks-2;
1553         int d0_idx = raid6_d0(sh);
1554         int faila = -1, failb = -1;
1555         int target = sh->ops.target;
1556         int target2 = sh->ops.target2;
1557         struct r5dev *tgt = &sh->dev[target];
1558         struct r5dev *tgt2 = &sh->dev[target2];
1559         struct dma_async_tx_descriptor *tx;
1560         struct page **blocks = to_addr_page(percpu, 0);
1561         struct async_submit_ctl submit;
1562
1563         BUG_ON(sh->batch_head);
1564         pr_debug("%s: stripe %llu block1: %d block2: %d\n",
1565                  __func__, (unsigned long long)sh->sector, target, target2);
1566         BUG_ON(target < 0 || target2 < 0);
1567         BUG_ON(!test_bit(R5_Wantcompute, &tgt->flags));
1568         BUG_ON(!test_bit(R5_Wantcompute, &tgt2->flags));
1569
1570         /* we need to open-code set_syndrome_sources to handle the
1571          * slot number conversion for 'faila' and 'failb'
1572          */
1573         for (i = 0; i < disks ; i++)
1574                 blocks[i] = NULL;
1575         count = 0;
1576         i = d0_idx;
1577         do {
1578                 int slot = raid6_idx_to_slot(i, sh, &count, syndrome_disks);
1579
1580                 blocks[slot] = sh->dev[i].page;
1581
1582                 if (i == target)
1583                         faila = slot;
1584                 if (i == target2)
1585                         failb = slot;
1586                 i = raid6_next_disk(i, disks);
1587         } while (i != d0_idx);
1588
1589         BUG_ON(faila == failb);
1590         if (failb < faila)
1591                 swap(faila, failb);
1592         pr_debug("%s: stripe: %llu faila: %d failb: %d\n",
1593                  __func__, (unsigned long long)sh->sector, faila, failb);
1594
1595         atomic_inc(&sh->count);
1596
1597         if (failb == syndrome_disks+1) {
1598                 /* Q disk is one of the missing disks */
1599                 if (faila == syndrome_disks) {
1600                         /* Missing P+Q, just recompute */
1601                         init_async_submit(&submit, ASYNC_TX_FENCE, NULL,
1602                                           ops_complete_compute, sh,
1603                                           to_addr_conv(sh, percpu, 0));
1604                         return async_gen_syndrome(blocks, 0, syndrome_disks+2,
1605                                                   STRIPE_SIZE, &submit);
1606                 } else {
1607                         struct page *dest;
1608                         int data_target;
1609                         int qd_idx = sh->qd_idx;
1610
1611                         /* Missing D+Q: recompute D from P, then recompute Q */
1612                         if (target == qd_idx)
1613                                 data_target = target2;
1614                         else
1615                                 data_target = target;
1616
1617                         count = 0;
1618                         for (i = disks; i-- ; ) {
1619                                 if (i == data_target || i == qd_idx)
1620                                         continue;
1621                                 blocks[count++] = sh->dev[i].page;
1622                         }
1623                         dest = sh->dev[data_target].page;
1624                         init_async_submit(&submit,
1625                                           ASYNC_TX_FENCE|ASYNC_TX_XOR_ZERO_DST,
1626                                           NULL, NULL, NULL,
1627                                           to_addr_conv(sh, percpu, 0));
1628                         tx = async_xor(dest, blocks, 0, count, STRIPE_SIZE,
1629                                        &submit);
1630
1631                         count = set_syndrome_sources(blocks, sh, SYNDROME_SRC_ALL);
1632                         init_async_submit(&submit, ASYNC_TX_FENCE, tx,
1633                                           ops_complete_compute, sh,
1634                                           to_addr_conv(sh, percpu, 0));
1635                         return async_gen_syndrome(blocks, 0, count+2,
1636                                                   STRIPE_SIZE, &submit);
1637                 }
1638         } else {
1639                 init_async_submit(&submit, ASYNC_TX_FENCE, NULL,
1640                                   ops_complete_compute, sh,
1641                                   to_addr_conv(sh, percpu, 0));
1642                 if (failb == syndrome_disks) {
1643                         /* We're missing D+P. */
1644                         return async_raid6_datap_recov(syndrome_disks+2,
1645                                                        STRIPE_SIZE, faila,
1646                                                        blocks, &submit);
1647                 } else {
1648                         /* We're missing D+D. */
1649                         return async_raid6_2data_recov(syndrome_disks+2,
1650                                                        STRIPE_SIZE, faila, failb,
1651                                                        blocks, &submit);
1652                 }
1653         }
1654 }
1655
1656 static void ops_complete_prexor(void *stripe_head_ref)
1657 {
1658         struct stripe_head *sh = stripe_head_ref;
1659
1660         pr_debug("%s: stripe %llu\n", __func__,
1661                 (unsigned long long)sh->sector);
1662
1663         if (r5c_is_writeback(sh->raid_conf->log))
1664                 /*
1665                  * raid5-cache write back uses orig_page during prexor.
1666                  * After prexor, it is time to free orig_page
1667                  */
1668                 r5c_release_extra_page(sh);
1669 }
1670
1671 static struct dma_async_tx_descriptor *
1672 ops_run_prexor5(struct stripe_head *sh, struct raid5_percpu *percpu,
1673                 struct dma_async_tx_descriptor *tx)
1674 {
1675         int disks = sh->disks;
1676         struct page **xor_srcs = to_addr_page(percpu, 0);
1677         int count = 0, pd_idx = sh->pd_idx, i;
1678         struct async_submit_ctl submit;
1679
1680         /* existing parity data subtracted */
1681         struct page *xor_dest = xor_srcs[count++] = sh->dev[pd_idx].page;
1682
1683         BUG_ON(sh->batch_head);
1684         pr_debug("%s: stripe %llu\n", __func__,
1685                 (unsigned long long)sh->sector);
1686
1687         for (i = disks; i--; ) {
1688                 struct r5dev *dev = &sh->dev[i];
1689                 /* Only process blocks that are known to be uptodate */
1690                 if (test_bit(R5_InJournal, &dev->flags))
1691                         xor_srcs[count++] = dev->orig_page;
1692                 else if (test_bit(R5_Wantdrain, &dev->flags))
1693                         xor_srcs[count++] = dev->page;
1694         }
1695
1696         init_async_submit(&submit, ASYNC_TX_FENCE|ASYNC_TX_XOR_DROP_DST, tx,
1697                           ops_complete_prexor, sh, to_addr_conv(sh, percpu, 0));
1698         tx = async_xor(xor_dest, xor_srcs, 0, count, STRIPE_SIZE, &submit);
1699
1700         return tx;
1701 }
1702
1703 static struct dma_async_tx_descriptor *
1704 ops_run_prexor6(struct stripe_head *sh, struct raid5_percpu *percpu,
1705                 struct dma_async_tx_descriptor *tx)
1706 {
1707         struct page **blocks = to_addr_page(percpu, 0);
1708         int count;
1709         struct async_submit_ctl submit;
1710
1711         pr_debug("%s: stripe %llu\n", __func__,
1712                 (unsigned long long)sh->sector);
1713
1714         count = set_syndrome_sources(blocks, sh, SYNDROME_SRC_WANT_DRAIN);
1715
1716         init_async_submit(&submit, ASYNC_TX_FENCE|ASYNC_TX_PQ_XOR_DST, tx,
1717                           ops_complete_prexor, sh, to_addr_conv(sh, percpu, 0));
1718         tx = async_gen_syndrome(blocks, 0, count+2, STRIPE_SIZE,  &submit);
1719
1720         return tx;
1721 }
1722
1723 static struct dma_async_tx_descriptor *
1724 ops_run_biodrain(struct stripe_head *sh, struct dma_async_tx_descriptor *tx)
1725 {
1726         struct r5conf *conf = sh->raid_conf;
1727         int disks = sh->disks;
1728         int i;
1729         struct stripe_head *head_sh = sh;
1730
1731         pr_debug("%s: stripe %llu\n", __func__,
1732                 (unsigned long long)sh->sector);
1733
1734         for (i = disks; i--; ) {
1735                 struct r5dev *dev;
1736                 struct bio *chosen;
1737
1738                 sh = head_sh;
1739                 if (test_and_clear_bit(R5_Wantdrain, &head_sh->dev[i].flags)) {
1740                         struct bio *wbi;
1741
1742 again:
1743                         dev = &sh->dev[i];
1744                         /*
1745                          * clear R5_InJournal, so when rewriting a page in
1746                          * journal, it is not skipped by r5l_log_stripe()
1747                          */
1748                         clear_bit(R5_InJournal, &dev->flags);
1749                         spin_lock_irq(&sh->stripe_lock);
1750                         chosen = dev->towrite;
1751                         dev->towrite = NULL;
1752                         sh->overwrite_disks = 0;
1753                         BUG_ON(dev->written);
1754                         wbi = dev->written = chosen;
1755                         spin_unlock_irq(&sh->stripe_lock);
1756                         WARN_ON(dev->page != dev->orig_page);
1757
1758                         while (wbi && wbi->bi_iter.bi_sector <
1759                                 dev->sector + STRIPE_SECTORS) {
1760                                 if (wbi->bi_opf & REQ_FUA)
1761                                         set_bit(R5_WantFUA, &dev->flags);
1762                                 if (wbi->bi_opf & REQ_SYNC)
1763                                         set_bit(R5_SyncIO, &dev->flags);
1764                                 if (bio_op(wbi) == REQ_OP_DISCARD)
1765                                         set_bit(R5_Discard, &dev->flags);
1766                                 else {
1767                                         tx = async_copy_data(1, wbi, &dev->page,
1768                                                              dev->sector, tx, sh,
1769                                                              r5c_is_writeback(conf->log));
1770                                         if (dev->page != dev->orig_page &&
1771                                             !r5c_is_writeback(conf->log)) {
1772                                                 set_bit(R5_SkipCopy, &dev->flags);
1773                                                 clear_bit(R5_UPTODATE, &dev->flags);
1774                                                 clear_bit(R5_OVERWRITE, &dev->flags);
1775                                         }
1776                                 }
1777                                 wbi = r5_next_bio(wbi, dev->sector);
1778                         }
1779
1780                         if (head_sh->batch_head) {
1781                                 sh = list_first_entry(&sh->batch_list,
1782                                                       struct stripe_head,
1783                                                       batch_list);
1784                                 if (sh == head_sh)
1785                                         continue;
1786                                 goto again;
1787                         }
1788                 }
1789         }
1790
1791         return tx;
1792 }
1793
1794 static void ops_complete_reconstruct(void *stripe_head_ref)
1795 {
1796         struct stripe_head *sh = stripe_head_ref;
1797         int disks = sh->disks;
1798         int pd_idx = sh->pd_idx;
1799         int qd_idx = sh->qd_idx;
1800         int i;
1801         bool fua = false, sync = false, discard = false;
1802
1803         pr_debug("%s: stripe %llu\n", __func__,
1804                 (unsigned long long)sh->sector);
1805
1806         for (i = disks; i--; ) {
1807                 fua |= test_bit(R5_WantFUA, &sh->dev[i].flags);
1808                 sync |= test_bit(R5_SyncIO, &sh->dev[i].flags);
1809                 discard |= test_bit(R5_Discard, &sh->dev[i].flags);
1810         }
1811
1812         for (i = disks; i--; ) {
1813                 struct r5dev *dev = &sh->dev[i];
1814
1815                 if (dev->written || i == pd_idx || i == qd_idx) {
1816                         if (!discard && !test_bit(R5_SkipCopy, &dev->flags))
1817                                 set_bit(R5_UPTODATE, &dev->flags);
1818                         if (fua)
1819                                 set_bit(R5_WantFUA, &dev->flags);
1820                         if (sync)
1821                                 set_bit(R5_SyncIO, &dev->flags);
1822                 }
1823         }
1824
1825         if (sh->reconstruct_state == reconstruct_state_drain_run)
1826                 sh->reconstruct_state = reconstruct_state_drain_result;
1827         else if (sh->reconstruct_state == reconstruct_state_prexor_drain_run)
1828                 sh->reconstruct_state = reconstruct_state_prexor_drain_result;
1829         else {
1830                 BUG_ON(sh->reconstruct_state != reconstruct_state_run);
1831                 sh->reconstruct_state = reconstruct_state_result;
1832         }
1833
1834         set_bit(STRIPE_HANDLE, &sh->state);
1835         raid5_release_stripe(sh);
1836 }
1837
1838 static void
1839 ops_run_reconstruct5(struct stripe_head *sh, struct raid5_percpu *percpu,
1840                      struct dma_async_tx_descriptor *tx)
1841 {
1842         int disks = sh->disks;
1843         struct page **xor_srcs;
1844         struct async_submit_ctl submit;
1845         int count, pd_idx = sh->pd_idx, i;
1846         struct page *xor_dest;
1847         int prexor = 0;
1848         unsigned long flags;
1849         int j = 0;
1850         struct stripe_head *head_sh = sh;
1851         int last_stripe;
1852
1853         pr_debug("%s: stripe %llu\n", __func__,
1854                 (unsigned long long)sh->sector);
1855
1856         for (i = 0; i < sh->disks; i++) {
1857                 if (pd_idx == i)
1858                         continue;
1859                 if (!test_bit(R5_Discard, &sh->dev[i].flags))
1860                         break;
1861         }
1862         if (i >= sh->disks) {
1863                 atomic_inc(&sh->count);
1864                 set_bit(R5_Discard, &sh->dev[pd_idx].flags);
1865                 ops_complete_reconstruct(sh);
1866                 return;
1867         }
1868 again:
1869         count = 0;
1870         xor_srcs = to_addr_page(percpu, j);
1871         /* check if prexor is active which means only process blocks
1872          * that are part of a read-modify-write (written)
1873          */
1874         if (head_sh->reconstruct_state == reconstruct_state_prexor_drain_run) {
1875                 prexor = 1;
1876                 xor_dest = xor_srcs[count++] = sh->dev[pd_idx].page;
1877                 for (i = disks; i--; ) {
1878                         struct r5dev *dev = &sh->dev[i];
1879                         if (head_sh->dev[i].written ||
1880                             test_bit(R5_InJournal, &head_sh->dev[i].flags))
1881                                 xor_srcs[count++] = dev->page;
1882                 }
1883         } else {
1884                 xor_dest = sh->dev[pd_idx].page;
1885                 for (i = disks; i--; ) {
1886                         struct r5dev *dev = &sh->dev[i];
1887                         if (i != pd_idx)
1888                                 xor_srcs[count++] = dev->page;
1889                 }
1890         }
1891
1892         /* 1/ if we prexor'd then the dest is reused as a source
1893          * 2/ if we did not prexor then we are redoing the parity
1894          * set ASYNC_TX_XOR_DROP_DST and ASYNC_TX_XOR_ZERO_DST
1895          * for the synchronous xor case
1896          */
1897         last_stripe = !head_sh->batch_head ||
1898                 list_first_entry(&sh->batch_list,
1899                                  struct stripe_head, batch_list) == head_sh;
1900         if (last_stripe) {
1901                 flags = ASYNC_TX_ACK |
1902                         (prexor ? ASYNC_TX_XOR_DROP_DST : ASYNC_TX_XOR_ZERO_DST);
1903
1904                 atomic_inc(&head_sh->count);
1905                 init_async_submit(&submit, flags, tx, ops_complete_reconstruct, head_sh,
1906                                   to_addr_conv(sh, percpu, j));
1907         } else {
1908                 flags = prexor ? ASYNC_TX_XOR_DROP_DST : ASYNC_TX_XOR_ZERO_DST;
1909                 init_async_submit(&submit, flags, tx, NULL, NULL,
1910                                   to_addr_conv(sh, percpu, j));
1911         }
1912
1913         if (unlikely(count == 1))
1914                 tx = async_memcpy(xor_dest, xor_srcs[0], 0, 0, STRIPE_SIZE, &submit);
1915         else
1916                 tx = async_xor(xor_dest, xor_srcs, 0, count, STRIPE_SIZE, &submit);
1917         if (!last_stripe) {
1918                 j++;
1919                 sh = list_first_entry(&sh->batch_list, struct stripe_head,
1920                                       batch_list);
1921                 goto again;
1922         }
1923 }
1924
1925 static void
1926 ops_run_reconstruct6(struct stripe_head *sh, struct raid5_percpu *percpu,
1927                      struct dma_async_tx_descriptor *tx)
1928 {
1929         struct async_submit_ctl submit;
1930         struct page **blocks;
1931         int count, i, j = 0;
1932         struct stripe_head *head_sh = sh;
1933         int last_stripe;
1934         int synflags;
1935         unsigned long txflags;
1936
1937         pr_debug("%s: stripe %llu\n", __func__, (unsigned long long)sh->sector);
1938
1939         for (i = 0; i < sh->disks; i++) {
1940                 if (sh->pd_idx == i || sh->qd_idx == i)
1941                         continue;
1942                 if (!test_bit(R5_Discard, &sh->dev[i].flags))
1943                         break;
1944         }
1945         if (i >= sh->disks) {
1946                 atomic_inc(&sh->count);
1947                 set_bit(R5_Discard, &sh->dev[sh->pd_idx].flags);
1948                 set_bit(R5_Discard, &sh->dev[sh->qd_idx].flags);
1949                 ops_complete_reconstruct(sh);
1950                 return;
1951         }
1952
1953 again:
1954         blocks = to_addr_page(percpu, j);
1955
1956         if (sh->reconstruct_state == reconstruct_state_prexor_drain_run) {
1957                 synflags = SYNDROME_SRC_WRITTEN;
1958                 txflags = ASYNC_TX_ACK | ASYNC_TX_PQ_XOR_DST;
1959         } else {
1960                 synflags = SYNDROME_SRC_ALL;
1961                 txflags = ASYNC_TX_ACK;
1962         }
1963
1964         count = set_syndrome_sources(blocks, sh, synflags);
1965         last_stripe = !head_sh->batch_head ||
1966                 list_first_entry(&sh->batch_list,
1967                                  struct stripe_head, batch_list) == head_sh;
1968
1969         if (last_stripe) {
1970                 atomic_inc(&head_sh->count);
1971                 init_async_submit(&submit, txflags, tx, ops_complete_reconstruct,
1972                                   head_sh, to_addr_conv(sh, percpu, j));
1973         } else
1974                 init_async_submit(&submit, 0, tx, NULL, NULL,
1975                                   to_addr_conv(sh, percpu, j));
1976         tx = async_gen_syndrome(blocks, 0, count+2, STRIPE_SIZE,  &submit);
1977         if (!last_stripe) {
1978                 j++;
1979                 sh = list_first_entry(&sh->batch_list, struct stripe_head,
1980                                       batch_list);
1981                 goto again;
1982         }
1983 }
1984
1985 static void ops_complete_check(void *stripe_head_ref)
1986 {
1987         struct stripe_head *sh = stripe_head_ref;
1988
1989         pr_debug("%s: stripe %llu\n", __func__,
1990                 (unsigned long long)sh->sector);
1991
1992         sh->check_state = check_state_check_result;
1993         set_bit(STRIPE_HANDLE, &sh->state);
1994         raid5_release_stripe(sh);
1995 }
1996
1997 static void ops_run_check_p(struct stripe_head *sh, struct raid5_percpu *percpu)
1998 {
1999         int disks = sh->disks;
2000         int pd_idx = sh->pd_idx;
2001         int qd_idx = sh->qd_idx;
2002         struct page *xor_dest;
2003         struct page **xor_srcs = to_addr_page(percpu, 0);
2004         struct dma_async_tx_descriptor *tx;
2005         struct async_submit_ctl submit;
2006         int count;
2007         int i;
2008
2009         pr_debug("%s: stripe %llu\n", __func__,
2010                 (unsigned long long)sh->sector);
2011
2012         BUG_ON(sh->batch_head);
2013         count = 0;
2014         xor_dest = sh->dev[pd_idx].page;
2015         xor_srcs[count++] = xor_dest;
2016         for (i = disks; i--; ) {
2017                 if (i == pd_idx || i == qd_idx)
2018                         continue;
2019                 xor_srcs[count++] = sh->dev[i].page;
2020         }
2021
2022         init_async_submit(&submit, 0, NULL, NULL, NULL,
2023                           to_addr_conv(sh, percpu, 0));
2024         tx = async_xor_val(xor_dest, xor_srcs, 0, count, STRIPE_SIZE,
2025                            &sh->ops.zero_sum_result, &submit);
2026
2027         atomic_inc(&sh->count);
2028         init_async_submit(&submit, ASYNC_TX_ACK, tx, ops_complete_check, sh, NULL);
2029         tx = async_trigger_callback(&submit);
2030 }
2031
2032 static void ops_run_check_pq(struct stripe_head *sh, struct raid5_percpu *percpu, int checkp)
2033 {
2034         struct page **srcs = to_addr_page(percpu, 0);
2035         struct async_submit_ctl submit;
2036         int count;
2037
2038         pr_debug("%s: stripe %llu checkp: %d\n", __func__,
2039                 (unsigned long long)sh->sector, checkp);
2040
2041         BUG_ON(sh->batch_head);
2042         count = set_syndrome_sources(srcs, sh, SYNDROME_SRC_ALL);
2043         if (!checkp)
2044                 srcs[count] = NULL;
2045
2046         atomic_inc(&sh->count);
2047         init_async_submit(&submit, ASYNC_TX_ACK, NULL, ops_complete_check,
2048                           sh, to_addr_conv(sh, percpu, 0));
2049         async_syndrome_val(srcs, 0, count+2, STRIPE_SIZE,
2050                            &sh->ops.zero_sum_result, percpu->spare_page, &submit);
2051 }
2052
2053 static void raid_run_ops(struct stripe_head *sh, unsigned long ops_request)
2054 {
2055         int overlap_clear = 0, i, disks = sh->disks;
2056         struct dma_async_tx_descriptor *tx = NULL;
2057         struct r5conf *conf = sh->raid_conf;
2058         int level = conf->level;
2059         struct raid5_percpu *percpu;
2060         unsigned long cpu;
2061
2062         cpu = get_cpu();
2063         percpu = per_cpu_ptr(conf->percpu, cpu);
2064         if (test_bit(STRIPE_OP_BIOFILL, &ops_request)) {
2065                 ops_run_biofill(sh);
2066                 overlap_clear++;
2067         }
2068
2069         if (test_bit(STRIPE_OP_COMPUTE_BLK, &ops_request)) {
2070                 if (level < 6)
2071                         tx = ops_run_compute5(sh, percpu);
2072                 else {
2073                         if (sh->ops.target2 < 0 || sh->ops.target < 0)
2074                                 tx = ops_run_compute6_1(sh, percpu);
2075                         else
2076                                 tx = ops_run_compute6_2(sh, percpu);
2077                 }
2078                 /* terminate the chain if reconstruct is not set to be run */
2079                 if (tx && !test_bit(STRIPE_OP_RECONSTRUCT, &ops_request))
2080                         async_tx_ack(tx);
2081         }
2082
2083         if (test_bit(STRIPE_OP_PREXOR, &ops_request)) {
2084                 if (level < 6)
2085                         tx = ops_run_prexor5(sh, percpu, tx);
2086                 else
2087                         tx = ops_run_prexor6(sh, percpu, tx);
2088         }
2089
2090         if (test_bit(STRIPE_OP_PARTIAL_PARITY, &ops_request))
2091                 tx = ops_run_partial_parity(sh, percpu, tx);
2092
2093         if (test_bit(STRIPE_OP_BIODRAIN, &ops_request)) {
2094                 tx = ops_run_biodrain(sh, tx);
2095                 overlap_clear++;
2096         }
2097
2098         if (test_bit(STRIPE_OP_RECONSTRUCT, &ops_request)) {
2099                 if (level < 6)
2100                         ops_run_reconstruct5(sh, percpu, tx);
2101                 else
2102                         ops_run_reconstruct6(sh, percpu, tx);
2103         }
2104
2105         if (test_bit(STRIPE_OP_CHECK, &ops_request)) {
2106                 if (sh->check_state == check_state_run)
2107                         ops_run_check_p(sh, percpu);
2108                 else if (sh->check_state == check_state_run_q)
2109                         ops_run_check_pq(sh, percpu, 0);
2110                 else if (sh->check_state == check_state_run_pq)
2111                         ops_run_check_pq(sh, percpu, 1);
2112                 else
2113                         BUG();
2114         }
2115
2116         if (overlap_clear && !sh->batch_head)
2117                 for (i = disks; i--; ) {
2118                         struct r5dev *dev = &sh->dev[i];
2119                         if (test_and_clear_bit(R5_Overlap, &dev->flags))
2120                                 wake_up(&sh->raid_conf->wait_for_overlap);
2121                 }
2122         put_cpu();
2123 }
2124
2125 static void free_stripe(struct kmem_cache *sc, struct stripe_head *sh)
2126 {
2127         if (sh->ppl_page)
2128                 __free_page(sh->ppl_page);
2129         kmem_cache_free(sc, sh);
2130 }
2131
2132 static struct stripe_head *alloc_stripe(struct kmem_cache *sc, gfp_t gfp,
2133         int disks, struct r5conf *conf)
2134 {
2135         struct stripe_head *sh;
2136         int i;
2137
2138         sh = kmem_cache_zalloc(sc, gfp);
2139         if (sh) {
2140                 spin_lock_init(&sh->stripe_lock);
2141                 spin_lock_init(&sh->batch_lock);
2142                 INIT_LIST_HEAD(&sh->batch_list);
2143                 INIT_LIST_HEAD(&sh->lru);
2144                 INIT_LIST_HEAD(&sh->r5c);
2145                 INIT_LIST_HEAD(&sh->log_list);
2146                 atomic_set(&sh->count, 1);
2147                 sh->raid_conf = conf;
2148                 sh->log_start = MaxSector;
2149                 for (i = 0; i < disks; i++) {
2150                         struct r5dev *dev = &sh->dev[i];
2151
2152                         bio_init(&dev->req, &dev->vec, 1);
2153                         bio_init(&dev->rreq, &dev->rvec, 1);
2154                 }
2155
2156                 if (raid5_has_ppl(conf)) {
2157                         sh->ppl_page = alloc_page(gfp);
2158                         if (!sh->ppl_page) {
2159                                 free_stripe(sc, sh);
2160                                 sh = NULL;
2161                         }
2162                 }
2163         }
2164         return sh;
2165 }
2166 static int grow_one_stripe(struct r5conf *conf, gfp_t gfp)
2167 {
2168         struct stripe_head *sh;
2169
2170         sh = alloc_stripe(conf->slab_cache, gfp, conf->pool_size, conf);
2171         if (!sh)
2172                 return 0;
2173
2174         if (grow_buffers(sh, gfp)) {
2175                 shrink_buffers(sh);
2176                 free_stripe(conf->slab_cache, sh);
2177                 return 0;
2178         }
2179         sh->hash_lock_index =
2180                 conf->max_nr_stripes % NR_STRIPE_HASH_LOCKS;
2181         /* we just created an active stripe so... */
2182         atomic_inc(&conf->active_stripes);
2183
2184         raid5_release_stripe(sh);
2185         conf->max_nr_stripes++;
2186         return 1;
2187 }
2188
2189 static int grow_stripes(struct r5conf *conf, int num)
2190 {
2191         struct kmem_cache *sc;
2192         int devs = max(conf->raid_disks, conf->previous_raid_disks);
2193
2194         if (conf->mddev->gendisk)
2195                 sprintf(conf->cache_name[0],
2196                         "raid%d-%s", conf->level, mdname(conf->mddev));
2197         else
2198                 sprintf(conf->cache_name[0],
2199                         "raid%d-%p", conf->level, conf->mddev);
2200         sprintf(conf->cache_name[1], "%s-alt", conf->cache_name[0]);
2201
2202         conf->active_name = 0;
2203         sc = kmem_cache_create(conf->cache_name[conf->active_name],
2204                                sizeof(struct stripe_head)+(devs-1)*sizeof(struct r5dev),
2205                                0, 0, NULL);
2206         if (!sc)
2207                 return 1;
2208         conf->slab_cache = sc;
2209         conf->pool_size = devs;
2210         while (num--)
2211                 if (!grow_one_stripe(conf, GFP_KERNEL))
2212                         return 1;
2213
2214         return 0;
2215 }
2216
2217 /**
2218  * scribble_len - return the required size of the scribble region
2219  * @num - total number of disks in the array
2220  *
2221  * The size must be enough to contain:
2222  * 1/ a struct page pointer for each device in the array +2
2223  * 2/ room to convert each entry in (1) to its corresponding dma
2224  *    (dma_map_page()) or page (page_address()) address.
2225  *
2226  * Note: the +2 is for the destination buffers of the ddf/raid6 case where we
2227  * calculate over all devices (not just the data blocks), using zeros in place
2228  * of the P and Q blocks.
2229  */
2230 static struct flex_array *scribble_alloc(int num, int cnt, gfp_t flags)
2231 {
2232         struct flex_array *ret;
2233         size_t len;
2234
2235         len = sizeof(struct page *) * (num+2) + sizeof(addr_conv_t) * (num+2);
2236         ret = flex_array_alloc(len, cnt, flags);
2237         if (!ret)
2238                 return NULL;
2239         /* always prealloc all elements, so no locking is required */
2240         if (flex_array_prealloc(ret, 0, cnt, flags)) {
2241                 flex_array_free(ret);
2242                 return NULL;
2243         }
2244         return ret;
2245 }
2246
2247 static int resize_chunks(struct r5conf *conf, int new_disks, int new_sectors)
2248 {
2249         unsigned long cpu;
2250         int err = 0;
2251
2252         /*
2253          * Never shrink. And mddev_suspend() could deadlock if this is called
2254          * from raid5d. In that case, scribble_disks and scribble_sectors
2255          * should equal to new_disks and new_sectors
2256          */
2257         if (conf->scribble_disks >= new_disks &&
2258             conf->scribble_sectors >= new_sectors)
2259                 return 0;
2260         mddev_suspend(conf->mddev);
2261         get_online_cpus();
2262         for_each_present_cpu(cpu) {
2263                 struct raid5_percpu *percpu;
2264                 struct flex_array *scribble;
2265
2266                 percpu = per_cpu_ptr(conf->percpu, cpu);
2267                 scribble = scribble_alloc(new_disks,
2268                                           new_sectors / STRIPE_SECTORS,
2269                                           GFP_NOIO);
2270
2271                 if (scribble) {
2272                         flex_array_free(percpu->scribble);
2273                         percpu->scribble = scribble;
2274                 } else {
2275                         err = -ENOMEM;
2276                         break;
2277                 }
2278         }
2279         put_online_cpus();
2280         mddev_resume(conf->mddev);
2281         if (!err) {
2282                 conf->scribble_disks = new_disks;
2283                 conf->scribble_sectors = new_sectors;
2284         }
2285         return err;
2286 }
2287
2288 static int resize_stripes(struct r5conf *conf, int newsize)
2289 {
2290         /* Make all the stripes able to hold 'newsize' devices.
2291          * New slots in each stripe get 'page' set to a new page.
2292          *
2293          * This happens in stages:
2294          * 1/ create a new kmem_cache and allocate the required number of
2295          *    stripe_heads.
2296          * 2/ gather all the old stripe_heads and transfer the pages across
2297          *    to the new stripe_heads.  This will have the side effect of
2298          *    freezing the array as once all stripe_heads have been collected,
2299          *    no IO will be possible.  Old stripe heads are freed once their
2300          *    pages have been transferred over, and the old kmem_cache is
2301          *    freed when all stripes are done.
2302          * 3/ reallocate conf->disks to be suitable bigger.  If this fails,
2303          *    we simple return a failure status - no need to clean anything up.
2304          * 4/ allocate new pages for the new slots in the new stripe_heads.
2305          *    If this fails, we don't bother trying the shrink the
2306          *    stripe_heads down again, we just leave them as they are.
2307          *    As each stripe_head is processed the new one is released into
2308          *    active service.
2309          *
2310          * Once step2 is started, we cannot afford to wait for a write,
2311          * so we use GFP_NOIO allocations.
2312          */
2313         struct stripe_head *osh, *nsh;
2314         LIST_HEAD(newstripes);
2315         struct disk_info *ndisks;
2316         int err = 0;
2317         struct kmem_cache *sc;
2318         int i;
2319         int hash, cnt;
2320
2321         md_allow_write(conf->mddev);
2322
2323         /* Step 1 */
2324         sc = kmem_cache_create(conf->cache_name[1-conf->active_name],
2325                                sizeof(struct stripe_head)+(newsize-1)*sizeof(struct r5dev),
2326                                0, 0, NULL);
2327         if (!sc)
2328                 return -ENOMEM;
2329
2330         /* Need to ensure auto-resizing doesn't interfere */
2331         mutex_lock(&conf->cache_size_mutex);
2332
2333         for (i = conf->max_nr_stripes; i; i--) {
2334                 nsh = alloc_stripe(sc, GFP_KERNEL, newsize, conf);
2335                 if (!nsh)
2336                         break;
2337
2338                 list_add(&nsh->lru, &newstripes);
2339         }
2340         if (i) {
2341                 /* didn't get enough, give up */
2342                 while (!list_empty(&newstripes)) {
2343                         nsh = list_entry(newstripes.next, struct stripe_head, lru);
2344                         list_del(&nsh->lru);
2345                         free_stripe(sc, nsh);
2346                 }
2347                 kmem_cache_destroy(sc);
2348                 mutex_unlock(&conf->cache_size_mutex);
2349                 return -ENOMEM;
2350         }
2351         /* Step 2 - Must use GFP_NOIO now.
2352          * OK, we have enough stripes, start collecting inactive
2353          * stripes and copying them over
2354          */
2355         hash = 0;
2356         cnt = 0;
2357         list_for_each_entry(nsh, &newstripes, lru) {
2358                 lock_device_hash_lock(conf, hash);
2359                 wait_event_cmd(conf->wait_for_stripe,
2360                                     !list_empty(conf->inactive_list + hash),
2361                                     unlock_device_hash_lock(conf, hash),
2362                                     lock_device_hash_lock(conf, hash));
2363                 osh = get_free_stripe(conf, hash);
2364                 unlock_device_hash_lock(conf, hash);
2365
2366                 for(i=0; i<conf->pool_size; i++) {
2367                         nsh->dev[i].page = osh->dev[i].page;
2368                         nsh->dev[i].orig_page = osh->dev[i].page;
2369                 }
2370                 nsh->hash_lock_index = hash;
2371                 free_stripe(conf->slab_cache, osh);
2372                 cnt++;
2373                 if (cnt >= conf->max_nr_stripes / NR_STRIPE_HASH_LOCKS +
2374                     !!((conf->max_nr_stripes % NR_STRIPE_HASH_LOCKS) > hash)) {
2375                         hash++;
2376                         cnt = 0;
2377                 }
2378         }
2379         kmem_cache_destroy(conf->slab_cache);
2380
2381         /* Step 3.
2382          * At this point, we are holding all the stripes so the array
2383          * is completely stalled, so now is a good time to resize
2384          * conf->disks and the scribble region
2385          */
2386         ndisks = kzalloc(newsize * sizeof(struct disk_info), GFP_NOIO);
2387         if (ndisks) {
2388                 for (i = 0; i < conf->pool_size; i++)
2389                         ndisks[i] = conf->disks[i];
2390
2391                 for (i = conf->pool_size; i < newsize; i++) {
2392                         ndisks[i].extra_page = alloc_page(GFP_NOIO);
2393                         if (!ndisks[i].extra_page)
2394                                 err = -ENOMEM;
2395                 }
2396
2397                 if (err) {
2398                         for (i = conf->pool_size; i < newsize; i++)
2399                                 if (ndisks[i].extra_page)
2400                                         put_page(ndisks[i].extra_page);
2401                         kfree(ndisks);
2402                 } else {
2403                         kfree(conf->disks);
2404                         conf->disks = ndisks;
2405                 }
2406         } else
2407                 err = -ENOMEM;
2408
2409         mutex_unlock(&conf->cache_size_mutex);
2410
2411         conf->slab_cache = sc;
2412         conf->active_name = 1-conf->active_name;
2413
2414         /* Step 4, return new stripes to service */
2415         while(!list_empty(&newstripes)) {
2416                 nsh = list_entry(newstripes.next, struct stripe_head, lru);
2417                 list_del_init(&nsh->lru);
2418
2419                 for (i=conf->raid_disks; i < newsize; i++)
2420                         if (nsh->dev[i].page == NULL) {
2421                                 struct page *p = alloc_page(GFP_NOIO);
2422                                 nsh->dev[i].page = p;
2423                                 nsh->dev[i].orig_page = p;
2424                                 if (!p)
2425                                         err = -ENOMEM;
2426                         }
2427                 raid5_release_stripe(nsh);
2428         }
2429         /* critical section pass, GFP_NOIO no longer needed */
2430
2431         if (!err)
2432                 conf->pool_size = newsize;
2433         return err;
2434 }
2435
2436 static int drop_one_stripe(struct r5conf *conf)
2437 {
2438         struct stripe_head *sh;
2439         int hash = (conf->max_nr_stripes - 1) & STRIPE_HASH_LOCKS_MASK;
2440
2441         spin_lock_irq(conf->hash_locks + hash);
2442         sh = get_free_stripe(conf, hash);
2443         spin_unlock_irq(conf->hash_locks + hash);
2444         if (!sh)
2445                 return 0;
2446         BUG_ON(atomic_read(&sh->count));
2447         shrink_buffers(sh);
2448         free_stripe(conf->slab_cache, sh);
2449         atomic_dec(&conf->active_stripes);
2450         conf->max_nr_stripes--;
2451         return 1;
2452 }
2453
2454 static void shrink_stripes(struct r5conf *conf)
2455 {
2456         while (conf->max_nr_stripes &&
2457                drop_one_stripe(conf))
2458                 ;
2459
2460         kmem_cache_destroy(conf->slab_cache);
2461         conf->slab_cache = NULL;
2462 }
2463
2464 static void raid5_end_read_request(struct bio * bi)
2465 {
2466         struct stripe_head *sh = bi->bi_private;
2467         struct r5conf *conf = sh->raid_conf;
2468         int disks = sh->disks, i;
2469         char b[BDEVNAME_SIZE];
2470         struct md_rdev *rdev = NULL;
2471         sector_t s;
2472
2473         for (i=0 ; i<disks; i++)
2474                 if (bi == &sh->dev[i].req)
2475                         break;
2476
2477         pr_debug("end_read_request %llu/%d, count: %d, error %d.\n",
2478                 (unsigned long long)sh->sector, i, atomic_read(&sh->count),
2479                 bi->bi_status);
2480         if (i == disks) {
2481                 bio_reset(bi);
2482                 BUG();
2483                 return;
2484         }
2485         if (test_bit(R5_ReadRepl, &sh->dev[i].flags))
2486                 /* If replacement finished while this request was outstanding,
2487                  * 'replacement' might be NULL already.
2488                  * In that case it moved down to 'rdev'.
2489                  * rdev is not removed until all requests are finished.
2490                  */
2491                 rdev = conf->disks[i].replacement;
2492         if (!rdev)
2493                 rdev = conf->disks[i].rdev;
2494
2495         if (use_new_offset(conf, sh))
2496                 s = sh->sector + rdev->new_data_offset;
2497         else
2498                 s = sh->sector + rdev->data_offset;
2499         if (!bi->bi_status) {
2500                 set_bit(R5_UPTODATE, &sh->dev[i].flags);
2501                 if (test_bit(R5_ReadError, &sh->dev[i].flags)) {
2502                         /* Note that this cannot happen on a
2503                          * replacement device.  We just fail those on
2504                          * any error
2505                          */
2506                         pr_info_ratelimited(
2507                                 "md/raid:%s: read error corrected (%lu sectors at %llu on %s)\n",
2508                                 mdname(conf->mddev), STRIPE_SECTORS,
2509                                 (unsigned long long)s,
2510                                 bdevname(rdev->bdev, b));
2511                         atomic_add(STRIPE_SECTORS, &rdev->corrected_errors);
2512                         clear_bit(R5_ReadError, &sh->dev[i].flags);
2513                         clear_bit(R5_ReWrite, &sh->dev[i].flags);
2514                 } else if (test_bit(R5_ReadNoMerge, &sh->dev[i].flags))
2515                         clear_bit(R5_ReadNoMerge, &sh->dev[i].flags);
2516
2517                 if (test_bit(R5_InJournal, &sh->dev[i].flags))
2518                         /*
2519                          * end read for a page in journal, this
2520                          * must be preparing for prexor in rmw
2521                          */
2522                         set_bit(R5_OrigPageUPTDODATE, &sh->dev[i].flags);
2523
2524                 if (atomic_read(&rdev->read_errors))
2525                         atomic_set(&rdev->read_errors, 0);
2526         } else {
2527                 const char *bdn = bdevname(rdev->bdev, b);
2528                 int retry = 0;
2529                 int set_bad = 0;
2530
2531                 clear_bit(R5_UPTODATE, &sh->dev[i].flags);
2532                 atomic_inc(&rdev->read_errors);
2533                 if (test_bit(R5_ReadRepl, &sh->dev[i].flags))
2534                         pr_warn_ratelimited(
2535                                 "md/raid:%s: read error on replacement device (sector %llu on %s).\n",
2536                                 mdname(conf->mddev),
2537                                 (unsigned long long)s,
2538                                 bdn);
2539                 else if (conf->mddev->degraded >= conf->max_degraded) {
2540                         set_bad = 1;
2541                         pr_warn_ratelimited(
2542                                 "md/raid:%s: read error not correctable (sector %llu on %s).\n",
2543                                 mdname(conf->mddev),
2544                                 (unsigned long long)s,
2545                                 bdn);
2546                 } else if (test_bit(R5_ReWrite, &sh->dev[i].flags)) {
2547                         /* Oh, no!!! */
2548                         set_bad = 1;
2549                         pr_warn_ratelimited(
2550                                 "md/raid:%s: read error NOT corrected!! (sector %llu on %s).\n",
2551                                 mdname(conf->mddev),
2552                                 (unsigned long long)s,
2553                                 bdn);
2554                 } else if (atomic_read(&rdev->read_errors)
2555                          > conf->max_nr_stripes)
2556                         pr_warn("md/raid:%s: Too many read errors, failing device %s.\n",
2557                                mdname(conf->mddev), bdn);
2558                 else
2559                         retry = 1;
2560                 if (set_bad && test_bit(In_sync, &rdev->flags)
2561                     && !test_bit(R5_ReadNoMerge, &sh->dev[i].flags))
2562                         retry = 1;
2563                 if (retry)
2564                         if (test_bit(R5_ReadNoMerge, &sh->dev[i].flags)) {
2565                                 set_bit(R5_ReadError, &sh->dev[i].flags);
2566                                 clear_bit(R5_ReadNoMerge, &sh->dev[i].flags);
2567                         } else
2568                                 set_bit(R5_ReadNoMerge, &sh->dev[i].flags);
2569                 else {
2570                         clear_bit(R5_ReadError, &sh->dev[i].flags);
2571                         clear_bit(R5_ReWrite, &sh->dev[i].flags);
2572                         if (!(set_bad
2573                               && test_bit(In_sync, &rdev->flags)
2574                               && rdev_set_badblocks(
2575                                       rdev, sh->sector, STRIPE_SECTORS, 0)))
2576                                 md_error(conf->mddev, rdev);
2577                 }
2578         }
2579         rdev_dec_pending(rdev, conf->mddev);
2580         bio_reset(bi);
2581         clear_bit(R5_LOCKED, &sh->dev[i].flags);
2582         set_bit(STRIPE_HANDLE, &sh->state);
2583         raid5_release_stripe(sh);
2584 }
2585
2586 static void raid5_end_write_request(struct bio *bi)
2587 {
2588         struct stripe_head *sh = bi->bi_private;
2589         struct r5conf *conf = sh->raid_conf;
2590         int disks = sh->disks, i;
2591         struct md_rdev *uninitialized_var(rdev);
2592         sector_t first_bad;
2593         int bad_sectors;
2594         int replacement = 0;
2595
2596         for (i = 0 ; i < disks; i++) {
2597                 if (bi == &sh->dev[i].req) {
2598                         rdev = conf->disks[i].rdev;
2599                         break;
2600                 }
2601                 if (bi == &sh->dev[i].rreq) {
2602                         rdev = conf->disks[i].replacement;
2603                         if (rdev)
2604                                 replacement = 1;
2605                         else
2606                                 /* rdev was removed and 'replacement'
2607                                  * replaced it.  rdev is not removed
2608                                  * until all requests are finished.
2609                                  */
2610                                 rdev = conf->disks[i].rdev;
2611                         break;
2612                 }
2613         }
2614         pr_debug("end_write_request %llu/%d, count %d, error: %d.\n",
2615                 (unsigned long long)sh->sector, i, atomic_read(&sh->count),
2616                 bi->bi_status);
2617         if (i == disks) {
2618                 bio_reset(bi);
2619                 BUG();
2620                 return;
2621         }
2622
2623         if (replacement) {
2624                 if (bi->bi_status)
2625                         md_error(conf->mddev, rdev);
2626                 else if (is_badblock(rdev, sh->sector,
2627                                      STRIPE_SECTORS,
2628                                      &first_bad, &bad_sectors))
2629                         set_bit(R5_MadeGoodRepl, &sh->dev[i].flags);
2630         } else {
2631                 if (bi->bi_status) {
2632                         set_bit(STRIPE_DEGRADED, &sh->state);
2633                         set_bit(WriteErrorSeen, &rdev->flags);
2634                         set_bit(R5_WriteError, &sh->dev[i].flags);
2635                         if (!test_and_set_bit(WantReplacement, &rdev->flags))
2636                                 set_bit(MD_RECOVERY_NEEDED,
2637                                         &rdev->mddev->recovery);
2638                 } else if (is_badblock(rdev, sh->sector,
2639                                        STRIPE_SECTORS,
2640                                        &first_bad, &bad_sectors)) {
2641                         set_bit(R5_MadeGood, &sh->dev[i].flags);
2642                         if (test_bit(R5_ReadError, &sh->dev[i].flags))
2643                                 /* That was a successful write so make
2644                                  * sure it looks like we already did
2645                                  * a re-write.
2646                                  */
2647                                 set_bit(R5_ReWrite, &sh->dev[i].flags);
2648                 }
2649         }
2650         rdev_dec_pending(rdev, conf->mddev);
2651
2652         if (sh->batch_head && bi->bi_status && !replacement)
2653                 set_bit(STRIPE_BATCH_ERR, &sh->batch_head->state);
2654
2655         bio_reset(bi);
2656         if (!test_and_clear_bit(R5_DOUBLE_LOCKED, &sh->dev[i].flags))
2657                 clear_bit(R5_LOCKED, &sh->dev[i].flags);
2658         set_bit(STRIPE_HANDLE, &sh->state);
2659         raid5_release_stripe(sh);
2660
2661         if (sh->batch_head && sh != sh->batch_head)
2662                 raid5_release_stripe(sh->batch_head);
2663 }
2664
2665 static void raid5_build_block(struct stripe_head *sh, int i, int previous)
2666 {
2667         struct r5dev *dev = &sh->dev[i];
2668
2669         dev->flags = 0;
2670         dev->sector = raid5_compute_blocknr(sh, i, previous);
2671 }
2672
2673 static void raid5_error(struct mddev *mddev, struct md_rdev *rdev)
2674 {
2675         char b[BDEVNAME_SIZE];
2676         struct r5conf *conf = mddev->private;
2677         unsigned long flags;
2678         pr_debug("raid456: error called\n");
2679
2680         spin_lock_irqsave(&conf->device_lock, flags);
2681         clear_bit(In_sync, &rdev->flags);
2682         mddev->degraded = raid5_calc_degraded(conf);
2683         spin_unlock_irqrestore(&conf->device_lock, flags);
2684         set_bit(MD_RECOVERY_INTR, &mddev->recovery);
2685
2686         set_bit(Blocked, &rdev->flags);
2687         set_bit(Faulty, &rdev->flags);
2688         set_mask_bits(&mddev->sb_flags, 0,
2689                       BIT(MD_SB_CHANGE_DEVS) | BIT(MD_SB_CHANGE_PENDING));
2690         pr_crit("md/raid:%s: Disk failure on %s, disabling device.\n"
2691                 "md/raid:%s: Operation continuing on %d devices.\n",
2692                 mdname(mddev),
2693                 bdevname(rdev->bdev, b),
2694                 mdname(mddev),
2695                 conf->raid_disks - mddev->degraded);
2696         r5c_update_on_rdev_error(mddev, rdev);
2697 }
2698
2699 /*
2700  * Input: a 'big' sector number,
2701  * Output: index of the data and parity disk, and the sector # in them.
2702  */
2703 sector_t raid5_compute_sector(struct r5conf *conf, sector_t r_sector,
2704                               int previous, int *dd_idx,
2705                               struct stripe_head *sh)
2706 {
2707         sector_t stripe, stripe2;
2708         sector_t chunk_number;
2709         unsigned int chunk_offset;
2710         int pd_idx, qd_idx;
2711         int ddf_layout = 0;
2712         sector_t new_sector;
2713         int algorithm = previous ? conf->prev_algo
2714                                  : conf->algorithm;
2715         int sectors_per_chunk = previous ? conf->prev_chunk_sectors
2716                                          : conf->chunk_sectors;
2717         int raid_disks = previous ? conf->previous_raid_disks
2718                                   : conf->raid_disks;
2719         int data_disks = raid_disks - conf->max_degraded;
2720
2721         /* First compute the information on this sector */
2722
2723         /*
2724          * Compute the chunk number and the sector offset inside the chunk
2725          */
2726         chunk_offset = sector_div(r_sector, sectors_per_chunk);
2727         chunk_number = r_sector;
2728
2729         /*
2730          * Compute the stripe number
2731          */
2732         stripe = chunk_number;
2733         *dd_idx = sector_div(stripe, data_disks);
2734         stripe2 = stripe;
2735         /*
2736          * Select the parity disk based on the user selected algorithm.
2737          */
2738         pd_idx = qd_idx = -1;
2739         switch(conf->level) {
2740         case 4:
2741                 pd_idx = data_disks;
2742                 break;
2743         case 5:
2744                 switch (algorithm) {
2745                 case ALGORITHM_LEFT_ASYMMETRIC:
2746                         pd_idx = data_disks - sector_div(stripe2, raid_disks);
2747                         if (*dd_idx >= pd_idx)
2748                                 (*dd_idx)++;
2749                         break;
2750                 case ALGORITHM_RIGHT_ASYMMETRIC:
2751                         pd_idx = sector_div(stripe2, raid_disks);
2752                         if (*dd_idx >= pd_idx)
2753                                 (*dd_idx)++;
2754                         break;
2755                 case ALGORITHM_LEFT_SYMMETRIC:
2756                         pd_idx = data_disks - sector_div(stripe2, raid_disks);
2757                         *dd_idx = (pd_idx + 1 + *dd_idx) % raid_disks;
2758                         break;
2759                 case ALGORITHM_RIGHT_SYMMETRIC:
2760                         pd_idx = sector_div(stripe2, raid_disks);
2761                         *dd_idx = (pd_idx + 1 + *dd_idx) % raid_disks;
2762                         break;
2763                 case ALGORITHM_PARITY_0:
2764                         pd_idx = 0;
2765                         (*dd_idx)++;
2766                         break;
2767                 case ALGORITHM_PARITY_N:
2768                         pd_idx = data_disks;
2769                         break;
2770                 default:
2771                         BUG();
2772                 }
2773                 break;
2774         case 6:
2775
2776                 switch (algorithm) {
2777                 case ALGORITHM_LEFT_ASYMMETRIC:
2778                         pd_idx = raid_disks - 1 - sector_div(stripe2, raid_disks);
2779                         qd_idx = pd_idx + 1;
2780                         if (pd_idx == raid_disks-1) {
2781                                 (*dd_idx)++;    /* Q D D D P */
2782                                 qd_idx = 0;
2783                         } else if (*dd_idx >= pd_idx)
2784                                 (*dd_idx) += 2; /* D D P Q D */
2785                         break;
2786                 case ALGORITHM_RIGHT_ASYMMETRIC:
2787                         pd_idx = sector_div(stripe2, raid_disks);
2788                         qd_idx = pd_idx + 1;
2789                         if (pd_idx == raid_disks-1) {
2790                                 (*dd_idx)++;    /* Q D D D P */
2791                                 qd_idx = 0;
2792                         } else if (*dd_idx >= pd_idx)
2793                                 (*dd_idx) += 2; /* D D P Q D */
2794                         break;
2795                 case ALGORITHM_LEFT_SYMMETRIC:
2796                         pd_idx = raid_disks - 1 - sector_div(stripe2, raid_disks);
2797                         qd_idx = (pd_idx + 1) % raid_disks;
2798                         *dd_idx = (pd_idx + 2 + *dd_idx) % raid_disks;
2799                         break;
2800                 case ALGORITHM_RIGHT_SYMMETRIC:
2801                         pd_idx = sector_div(stripe2, raid_disks);
2802                         qd_idx = (pd_idx + 1) % raid_disks;
2803                         *dd_idx = (pd_idx + 2 + *dd_idx) % raid_disks;
2804                         break;
2805
2806                 case ALGORITHM_PARITY_0:
2807                         pd_idx = 0;
2808                         qd_idx = 1;
2809                         (*dd_idx) += 2;
2810                         break;
2811                 case ALGORITHM_PARITY_N:
2812                         pd_idx = data_disks;
2813                         qd_idx = data_disks + 1;
2814                         break;
2815
2816                 case ALGORITHM_ROTATING_ZERO_RESTART:
2817                         /* Exactly the same as RIGHT_ASYMMETRIC, but or
2818                          * of blocks for computing Q is different.
2819                          */
2820                         pd_idx = sector_div(stripe2, raid_disks);
2821                         qd_idx = pd_idx + 1;
2822                         if (pd_idx == raid_disks-1) {
2823                                 (*dd_idx)++;    /* Q D D D P */
2824                                 qd_idx = 0;
2825                         } else if (*dd_idx >= pd_idx)
2826                                 (*dd_idx) += 2; /* D D P Q D */
2827                         ddf_layout = 1;
2828                         break;
2829
2830                 case ALGORITHM_ROTATING_N_RESTART:
2831                         /* Same a left_asymmetric, by first stripe is
2832                          * D D D P Q  rather than
2833                          * Q D D D P
2834                          */
2835                         stripe2 += 1;
2836                         pd_idx = raid_disks - 1 - sector_div(stripe2, raid_disks);
2837                         qd_idx = pd_idx + 1;
2838                         if (pd_idx == raid_disks-1) {
2839                                 (*dd_idx)++;    /* Q D D D P */
2840                                 qd_idx = 0;
2841                         } else if (*dd_idx >= pd_idx)
2842                                 (*dd_idx) += 2; /* D D P Q D */
2843                         ddf_layout = 1;
2844                         break;
2845
2846                 case ALGORITHM_ROTATING_N_CONTINUE:
2847                         /* Same as left_symmetric but Q is before P */
2848                         pd_idx = raid_disks - 1 - sector_div(stripe2, raid_disks);
2849                         qd_idx = (pd_idx + raid_disks - 1) % raid_disks;
2850                         *dd_idx = (pd_idx + 1 + *dd_idx) % raid_disks;
2851                         ddf_layout = 1;
2852                         break;
2853
2854                 case ALGORITHM_LEFT_ASYMMETRIC_6:
2855                         /* RAID5 left_asymmetric, with Q on last device */
2856                         pd_idx = data_disks - sector_div(stripe2, raid_disks-1);
2857                         if (*dd_idx >= pd_idx)
2858                                 (*dd_idx)++;
2859                         qd_idx = raid_disks - 1;
2860                         break;
2861
2862                 case ALGORITHM_RIGHT_ASYMMETRIC_6:
2863                         pd_idx = sector_div(stripe2, raid_disks-1);
2864                         if (*dd_idx >= pd_idx)
2865                                 (*dd_idx)++;
2866                         qd_idx = raid_disks - 1;
2867                         break;
2868
2869                 case ALGORITHM_LEFT_SYMMETRIC_6:
2870                         pd_idx = data_disks - sector_div(stripe2, raid_disks-1);
2871                         *dd_idx = (pd_idx + 1 + *dd_idx) % (raid_disks-1);
2872                         qd_idx = raid_disks - 1;
2873                         break;
2874
2875                 case ALGORITHM_RIGHT_SYMMETRIC_6:
2876                         pd_idx = sector_div(stripe2, raid_disks-1);
2877                         *dd_idx = (pd_idx + 1 + *dd_idx) % (raid_disks-1);
2878                         qd_idx = raid_disks - 1;
2879                         break;
2880
2881                 case ALGORITHM_PARITY_0_6:
2882                         pd_idx = 0;
2883                         (*dd_idx)++;
2884                         qd_idx = raid_disks - 1;
2885                         break;
2886
2887                 default:
2888                         BUG();
2889                 }
2890                 break;
2891         }
2892
2893         if (sh) {
2894                 sh->pd_idx = pd_idx;
2895                 sh->qd_idx = qd_idx;
2896                 sh->ddf_layout = ddf_layout;
2897         }
2898         /*
2899          * Finally, compute the new sector number
2900          */
2901         new_sector = (sector_t)stripe * sectors_per_chunk + chunk_offset;
2902         return new_sector;
2903 }
2904
2905 sector_t raid5_compute_blocknr(struct stripe_head *sh, int i, int previous)
2906 {
2907         struct r5conf *conf = sh->raid_conf;
2908         int raid_disks = sh->disks;
2909         int data_disks = raid_disks - conf->max_degraded;
2910         sector_t new_sector = sh->sector, check;
2911         int sectors_per_chunk = previous ? conf->prev_chunk_sectors
2912                                          : conf->chunk_sectors;
2913         int algorithm = previous ? conf->prev_algo
2914                                  : conf->algorithm;
2915         sector_t stripe;
2916         int chunk_offset;
2917         sector_t chunk_number;
2918         int dummy1, dd_idx = i;
2919         sector_t r_sector;
2920         struct stripe_head sh2;
2921
2922         chunk_offset = sector_div(new_sector, sectors_per_chunk);
2923         stripe = new_sector;
2924
2925         if (i == sh->pd_idx)
2926                 return 0;
2927         switch(conf->level) {
2928         case 4: break;
2929         case 5:
2930                 switch (algorithm) {
2931                 case ALGORITHM_LEFT_ASYMMETRIC:
2932                 case ALGORITHM_RIGHT_ASYMMETRIC:
2933                         if (i > sh->pd_idx)
2934                                 i--;
2935                         break;
2936                 case ALGORITHM_LEFT_SYMMETRIC:
2937                 case ALGORITHM_RIGHT_SYMMETRIC:
2938                         if (i < sh->pd_idx)
2939                                 i += raid_disks;
2940                         i -= (sh->pd_idx + 1);
2941                         break;
2942                 case ALGORITHM_PARITY_0:
2943                         i -= 1;
2944                         break;
2945                 case ALGORITHM_PARITY_N:
2946                         break;
2947                 default:
2948                         BUG();
2949                 }
2950                 break;
2951         case 6:
2952                 if (i == sh->qd_idx)
2953                         return 0; /* It is the Q disk */
2954                 switch (algorithm) {
2955                 case ALGORITHM_LEFT_ASYMMETRIC:
2956                 case ALGORITHM_RIGHT_ASYMMETRIC:
2957                 case ALGORITHM_ROTATING_ZERO_RESTART:
2958                 case ALGORITHM_ROTATING_N_RESTART:
2959                         if (sh->pd_idx == raid_disks-1)
2960                                 i--;    /* Q D D D P */
2961                         else if (i > sh->pd_idx)
2962                                 i -= 2; /* D D P Q D */
2963                         break;
2964                 case ALGORITHM_LEFT_SYMMETRIC:
2965                 case ALGORITHM_RIGHT_SYMMETRIC:
2966                         if (sh->pd_idx == raid_disks-1)
2967                                 i--; /* Q D D D P */
2968                         else {
2969                                 /* D D P Q D */
2970                                 if (i < sh->pd_idx)
2971                                         i += raid_disks;
2972                                 i -= (sh->pd_idx + 2);
2973                         }
2974                         break;
2975                 case ALGORITHM_PARITY_0:
2976                         i -= 2;
2977                         break;
2978                 case ALGORITHM_PARITY_N:
2979                         break;
2980                 case ALGORITHM_ROTATING_N_CONTINUE:
2981                         /* Like left_symmetric, but P is before Q */
2982                         if (sh->pd_idx == 0)
2983                                 i--;    /* P D D D Q */
2984                         else {
2985                                 /* D D Q P D */
2986                                 if (i < sh->pd_idx)
2987                                         i += raid_disks;
2988                                 i -= (sh->pd_idx + 1);
2989                         }
2990                         break;
2991                 case ALGORITHM_LEFT_ASYMMETRIC_6:
2992                 case ALGORITHM_RIGHT_ASYMMETRIC_6:
2993                         if (i > sh->pd_idx)
2994                                 i--;
2995                         break;
2996                 case ALGORITHM_LEFT_SYMMETRIC_6:
2997                 case ALGORITHM_RIGHT_SYMMETRIC_6:
2998                         if (i < sh->pd_idx)
2999                                 i += data_disks + 1;
3000                         i -= (sh->pd_idx + 1);
3001                         break;
3002                 case ALGORITHM_PARITY_0_6:
3003                         i -= 1;
3004                         break;
3005                 default:
3006                         BUG();
3007                 }
3008                 break;
3009         }
3010
3011         chunk_number = stripe * data_disks + i;
3012         r_sector = chunk_number * sectors_per_chunk + chunk_offset;
3013
3014         check = raid5_compute_sector(conf, r_sector,
3015                                      previous, &dummy1, &sh2);
3016         if (check != sh->sector || dummy1 != dd_idx || sh2.pd_idx != sh->pd_idx
3017                 || sh2.qd_idx != sh->qd_idx) {
3018                 pr_warn("md/raid:%s: compute_blocknr: map not correct\n",
3019                         mdname(conf->mddev));
3020                 return 0;
3021         }
3022         return r_sector;
3023 }
3024
3025 /*
3026  * There are cases where we want handle_stripe_dirtying() and
3027  * schedule_reconstruction() to delay towrite to some dev of a stripe.
3028  *
3029  * This function checks whether we want to delay the towrite. Specifically,
3030  * we delay the towrite when:
3031  *
3032  *   1. degraded stripe has a non-overwrite to the missing dev, AND this
3033  *      stripe has data in journal (for other devices).
3034  *
3035  *      In this case, when reading data for the non-overwrite dev, it is
3036  *      necessary to handle complex rmw of write back cache (prexor with
3037  *      orig_page, and xor with page). To keep read path simple, we would
3038  *      like to flush data in journal to RAID disks first, so complex rmw
3039  *      is handled in the write patch (handle_stripe_dirtying).
3040  *
3041  *   2. when journal space is critical (R5C_LOG_CRITICAL=1)
3042  *
3043  *      It is important to be able to flush all stripes in raid5-cache.
3044  *      Therefore, we need reserve some space on the journal device for
3045  *      these flushes. If flush operation includes pending writes to the
3046  *      stripe, we need to reserve (conf->raid_disk + 1) pages per stripe
3047  *      for the flush out. If we exclude these pending writes from flush
3048  *      operation, we only need (conf->max_degraded + 1) pages per stripe.
3049  *      Therefore, excluding pending writes in these cases enables more
3050  *      efficient use of the journal device.
3051  *
3052  *      Note: To make sure the stripe makes progress, we only delay
3053  *      towrite for stripes with data already in journal (injournal > 0).
3054  *      When LOG_CRITICAL, stripes with injournal == 0 will be sent to
3055  *      no_space_stripes list.
3056  *
3057  *   3. during journal failure
3058  *      In journal failure, we try to flush all cached data to raid disks
3059  *      based on data in stripe cache. The array is read-only to upper
3060  *      layers, so we would skip all pending writes.
3061  *
3062  */
3063 static inline bool delay_towrite(struct r5conf *conf,
3064                                  struct r5dev *dev,
3065                                  struct stripe_head_state *s)
3066 {
3067         /* case 1 above */
3068         if (!test_bit(R5_OVERWRITE, &dev->flags) &&
3069             !test_bit(R5_Insync, &dev->flags) && s->injournal)
3070                 return true;
3071         /* case 2 above */
3072         if (test_bit(R5C_LOG_CRITICAL, &conf->cache_state) &&
3073             s->injournal > 0)
3074                 return true;
3075         /* case 3 above */
3076         if (s->log_failed && s->injournal)
3077                 return true;
3078         return false;
3079 }
3080
3081 static void
3082 schedule_reconstruction(struct stripe_head *sh, struct stripe_head_state *s,
3083                          int rcw, int expand)
3084 {
3085         int i, pd_idx = sh->pd_idx, qd_idx = sh->qd_idx, disks = sh->disks;
3086         struct r5conf *conf = sh->raid_conf;
3087         int level = conf->level;
3088
3089         if (rcw) {
3090                 /*
3091                  * In some cases, handle_stripe_dirtying initially decided to
3092                  * run rmw and allocates extra page for prexor. However, rcw is
3093                  * cheaper later on. We need to free the extra page now,
3094                  * because we won't be able to do that in ops_complete_prexor().
3095                  */
3096                 r5c_release_extra_page(sh);
3097
3098                 for (i = disks; i--; ) {
3099                         struct r5dev *dev = &sh->dev[i];
3100
3101                         if (dev->towrite && !delay_towrite(conf, dev, s)) {
3102                                 set_bit(R5_LOCKED, &dev->flags);
3103                                 set_bit(R5_Wantdrain, &dev->flags);
3104                                 if (!expand)
3105                                         clear_bit(R5_UPTODATE, &dev->flags);
3106                                 s->locked++;
3107                         } else if (test_bit(R5_InJournal, &dev->flags)) {
3108                                 set_bit(R5_LOCKED, &dev->flags);
3109                                 s->locked++;
3110                         }
3111                 }
3112                 /* if we are not expanding this is a proper write request, and
3113                  * there will be bios with new data to be drained into the
3114                  * stripe cache
3115                  */
3116                 if (!expand) {
3117                         if (!s->locked)
3118                                 /* False alarm, nothing to do */
3119                                 return;
3120                         sh->reconstruct_state = reconstruct_state_drain_run;
3121                         set_bit(STRIPE_OP_BIODRAIN, &s->ops_request);
3122                 } else
3123                         sh->reconstruct_state = reconstruct_state_run;
3124
3125                 set_bit(STRIPE_OP_RECONSTRUCT, &s->ops_request);
3126
3127                 if (s->locked + conf->max_degraded == disks)
3128                         if (!test_and_set_bit(STRIPE_FULL_WRITE, &sh->state))
3129                                 atomic_inc(&conf->pending_full_writes);
3130         } else {
3131                 BUG_ON(!(test_bit(R5_UPTODATE, &sh->dev[pd_idx].flags) ||
3132                         test_bit(R5_Wantcompute, &sh->dev[pd_idx].flags)));
3133                 BUG_ON(level == 6 &&
3134                         (!(test_bit(R5_UPTODATE, &sh->dev[qd_idx].flags) ||
3135                            test_bit(R5_Wantcompute, &sh->dev[qd_idx].flags))));
3136
3137                 for (i = disks; i--; ) {
3138                         struct r5dev *dev = &sh->dev[i];
3139                         if (i == pd_idx || i == qd_idx)
3140                                 continue;
3141
3142                         if (dev->towrite &&
3143                             (test_bit(R5_UPTODATE, &dev->flags) ||
3144                              test_bit(R5_Wantcompute, &dev->flags))) {
3145                                 set_bit(R5_Wantdrain, &dev->flags);
3146                                 set_bit(R5_LOCKED, &dev->flags);
3147                                 clear_bit(R5_UPTODATE, &dev->flags);
3148                                 s->locked++;
3149                         } else if (test_bit(R5_InJournal, &dev->flags)) {
3150                                 set_bit(R5_LOCKED, &dev->flags);
3151                                 s->locked++;
3152                         }
3153                 }
3154                 if (!s->locked)
3155                         /* False alarm - nothing to do */
3156                         return;
3157                 sh->reconstruct_state = reconstruct_state_prexor_drain_run;
3158                 set_bit(STRIPE_OP_PREXOR, &s->ops_request);
3159                 set_bit(STRIPE_OP_BIODRAIN, &s->ops_request);
3160                 set_bit(STRIPE_OP_RECONSTRUCT, &s->ops_request);
3161         }
3162
3163         /* keep the parity disk(s) locked while asynchronous operations
3164          * are in flight
3165          */
3166         set_bit(R5_LOCKED, &sh->dev[pd_idx].flags);
3167         clear_bit(R5_UPTODATE, &sh->dev[pd_idx].flags);
3168         s->locked++;
3169
3170         if (level == 6) {
3171                 int qd_idx = sh->qd_idx;
3172                 struct r5dev *dev = &sh->dev[qd_idx];
3173
3174                 set_bit(R5_LOCKED, &dev->flags);
3175                 clear_bit(R5_UPTODATE, &dev->flags);
3176                 s->locked++;
3177         }
3178
3179         if (raid5_has_ppl(sh->raid_conf) && sh->ppl_page &&
3180             test_bit(STRIPE_OP_BIODRAIN, &s->ops_request) &&
3181             !test_bit(STRIPE_FULL_WRITE, &sh->state) &&
3182             test_bit(R5_Insync, &sh->dev[pd_idx].flags))
3183                 set_bit(STRIPE_OP_PARTIAL_PARITY, &s->ops_request);
3184
3185         pr_debug("%s: stripe %llu locked: %d ops_request: %lx\n",
3186                 __func__, (unsigned long long)sh->sector,
3187                 s->locked, s->ops_request);
3188 }
3189
3190 /*
3191  * Each stripe/dev can have one or more bion attached.
3192  * toread/towrite point to the first in a chain.
3193  * The bi_next chain must be in order.
3194  */
3195 static int add_stripe_bio(struct stripe_head *sh, struct bio *bi, int dd_idx,
3196                           int forwrite, int previous)
3197 {
3198         struct bio **bip;
3199         struct r5conf *conf = sh->raid_conf;
3200         int firstwrite=0;
3201
3202         pr_debug("adding bi b#%llu to stripe s#%llu\n",
3203                 (unsigned long long)bi->bi_iter.bi_sector,
3204                 (unsigned long long)sh->sector);
3205
3206         spin_lock_irq(&sh->stripe_lock);
3207         /* Don't allow new IO added to stripes in batch list */
3208         if (sh->batch_head)
3209                 goto overlap;
3210         if (forwrite) {
3211                 bip = &sh->dev[dd_idx].towrite;
3212                 if (*bip == NULL)
3213                         firstwrite = 1;
3214         } else
3215                 bip = &sh->dev[dd_idx].toread;
3216         while (*bip && (*bip)->bi_iter.bi_sector < bi->bi_iter.bi_sector) {
3217                 if (bio_end_sector(*bip) > bi->bi_iter.bi_sector)
3218                         goto overlap;
3219                 bip = & (*bip)->bi_next;
3220         }
3221         if (*bip && (*bip)->bi_iter.bi_sector < bio_end_sector(bi))
3222                 goto overlap;
3223
3224         if (forwrite && raid5_has_ppl(conf)) {
3225                 /*
3226                  * With PPL only writes to consecutive data chunks within a
3227                  * stripe are allowed because for a single stripe_head we can
3228                  * only have one PPL entry at a time, which describes one data
3229                  * range. Not really an overlap, but wait_for_overlap can be
3230                  * used to handle this.
3231                  */
3232                 sector_t sector;
3233                 sector_t first = 0;
3234                 sector_t last = 0;
3235                 int count = 0;
3236                 int i;
3237
3238                 for (i = 0; i < sh->disks; i++) {
3239                         if (i != sh->pd_idx &&
3240                             (i == dd_idx || sh->dev[i].towrite)) {
3241                                 sector = sh->dev[i].sector;
3242                                 if (count == 0 || sector < first)
3243                                         first = sector;
3244                                 if (sector > last)
3245                                         last = sector;
3246                                 count++;
3247                         }
3248                 }
3249
3250                 if (first + conf->chunk_sectors * (count - 1) != last)
3251                         goto overlap;
3252         }
3253
3254         if (!forwrite || previous)
3255                 clear_bit(STRIPE_BATCH_READY, &sh->state);
3256
3257         BUG_ON(*bip && bi->bi_next && (*bip) != bi->bi_next);
3258         if (*bip)
3259                 bi->bi_next = *bip;
3260         *bip = bi;
3261         bio_inc_remaining(bi);
3262         md_write_inc(conf->mddev, bi);
3263
3264         if (forwrite) {
3265                 /* check if page is covered */
3266                 sector_t sector = sh->dev[dd_idx].sector;
3267                 for (bi=sh->dev[dd_idx].towrite;
3268                      sector < sh->dev[dd_idx].sector + STRIPE_SECTORS &&
3269                              bi && bi->bi_iter.bi_sector <= sector;
3270                      bi = r5_next_bio(bi, sh->dev[dd_idx].sector)) {
3271                         if (bio_end_sector(bi) >= sector)
3272                                 sector = bio_end_sector(bi);
3273                 }
3274                 if (sector >= sh->dev[dd_idx].sector + STRIPE_SECTORS)
3275                         if (!test_and_set_bit(R5_OVERWRITE, &sh->dev[dd_idx].flags))
3276                                 sh->overwrite_disks++;
3277         }
3278
3279         pr_debug("added bi b#%llu to stripe s#%llu, disk %d.\n",
3280                 (unsigned long long)(*bip)->bi_iter.bi_sector,
3281                 (unsigned long long)sh->sector, dd_idx);
3282
3283         if (conf->mddev->bitmap && firstwrite) {
3284                 /* Cannot hold spinlock over bitmap_startwrite,
3285                  * but must ensure this isn't added to a batch until
3286                  * we have added to the bitmap and set bm_seq.
3287                  * So set STRIPE_BITMAP_PENDING to prevent
3288                  * batching.
3289                  * If multiple add_stripe_bio() calls race here they
3290                  * much all set STRIPE_BITMAP_PENDING.  So only the first one
3291                  * to complete "bitmap_startwrite" gets to set
3292                  * STRIPE_BIT_DELAY.  This is important as once a stripe
3293                  * is added to a batch, STRIPE_BIT_DELAY cannot be changed
3294                  * any more.
3295                  */
3296                 set_bit(STRIPE_BITMAP_PENDING, &sh->state);
3297                 spin_unlock_irq(&sh->stripe_lock);
3298                 bitmap_startwrite(conf->mddev->bitmap, sh->sector,
3299                                   STRIPE_SECTORS, 0);
3300                 spin_lock_irq(&sh->stripe_lock);
3301                 clear_bit(STRIPE_BITMAP_PENDING, &sh->state);
3302                 if (!sh->batch_head) {
3303                         sh->bm_seq = conf->seq_flush+1;
3304                         set_bit(STRIPE_BIT_DELAY, &sh->state);
3305                 }
3306         }
3307         spin_unlock_irq(&sh->stripe_lock);
3308
3309         if (stripe_can_batch(sh))
3310                 stripe_add_to_batch_list(conf, sh);
3311         return 1;
3312
3313  overlap:
3314         set_bit(R5_Overlap, &sh->dev[dd_idx].flags);
3315         spin_unlock_irq(&sh->stripe_lock);
3316         return 0;
3317 }
3318
3319 static void end_reshape(struct r5conf *conf);
3320
3321 static void stripe_set_idx(sector_t stripe, struct r5conf *conf, int previous,
3322                             struct stripe_head *sh)
3323 {
3324         int sectors_per_chunk =
3325                 previous ? conf->prev_chunk_sectors : conf->chunk_sectors;
3326         int dd_idx;
3327         int chunk_offset = sector_div(stripe, sectors_per_chunk);
3328         int disks = previous ? conf->previous_raid_disks : conf->raid_disks;
3329
3330         raid5_compute_sector(conf,
3331                              stripe * (disks - conf->max_degraded)
3332                              *sectors_per_chunk + chunk_offset,
3333                              previous,
3334                              &dd_idx, sh);
3335 }
3336
3337 static void
3338 handle_failed_stripe(struct r5conf *conf, struct stripe_head *sh,
3339                      struct stripe_head_state *s, int disks)
3340 {
3341         int i;
3342         BUG_ON(sh->batch_head);
3343         for (i = disks; i--; ) {
3344                 struct bio *bi;
3345                 int bitmap_end = 0;
3346
3347                 if (test_bit(R5_ReadError, &sh->dev[i].flags)) {
3348                         struct md_rdev *rdev;
3349                         rcu_read_lock();
3350                         rdev = rcu_dereference(conf->disks[i].rdev);
3351                         if (rdev && test_bit(In_sync, &rdev->flags) &&
3352                             !test_bit(Faulty, &rdev->flags))
3353                                 atomic_inc(&rdev->nr_pending);
3354                         else
3355                                 rdev = NULL;
3356                         rcu_read_unlock();
3357                         if (rdev) {
3358                                 if (!rdev_set_badblocks(
3359                                             rdev,
3360                                             sh->sector,
3361                                             STRIPE_SECTORS, 0))
3362                                         md_error(conf->mddev, rdev);
3363                                 rdev_dec_pending(rdev, conf->mddev);
3364                         }
3365                 }
3366                 spin_lock_irq(&sh->stripe_lock);
3367                 /* fail all writes first */
3368                 bi = sh->dev[i].towrite;
3369                 sh->dev[i].towrite = NULL;
3370                 sh->overwrite_disks = 0;
3371                 spin_unlock_irq(&sh->stripe_lock);
3372                 if (bi)
3373                         bitmap_end = 1;
3374
3375                 log_stripe_write_finished(sh);
3376
3377                 if (test_and_clear_bit(R5_Overlap, &sh->dev[i].flags))
3378                         wake_up(&conf->wait_for_overlap);
3379
3380                 while (bi && bi->bi_iter.bi_sector <
3381                         sh->dev[i].sector + STRIPE_SECTORS) {
3382                         struct bio *nextbi = r5_next_bio(bi, sh->dev[i].sector);
3383
3384                         md_write_end(conf->mddev);
3385                         bio_io_error(bi);
3386                         bi = nextbi;
3387                 }
3388                 if (bitmap_end)
3389                         bitmap_endwrite(conf->mddev->bitmap, sh->sector,
3390                                 STRIPE_SECTORS, 0, 0);
3391                 bitmap_end = 0;
3392                 /* and fail all 'written' */
3393                 bi = sh->dev[i].written;
3394                 sh->dev[i].written = NULL;
3395                 if (test_and_clear_bit(R5_SkipCopy, &sh->dev[i].flags)) {
3396                         WARN_ON(test_bit(R5_UPTODATE, &sh->dev[i].flags));
3397                         sh->dev[i].page = sh->dev[i].orig_page;
3398                 }
3399
3400                 if (bi) bitmap_end = 1;
3401                 while (bi && bi->bi_iter.bi_sector <
3402                        sh->dev[i].sector + STRIPE_SECTORS) {
3403                         struct bio *bi2 = r5_next_bio(bi, sh->dev[i].sector);
3404
3405                         md_write_end(conf->mddev);
3406                         bio_io_error(bi);
3407                         bi = bi2;
3408                 }
3409
3410                 /* fail any reads if this device is non-operational and
3411                  * the data has not reached the cache yet.
3412                  */
3413                 if (!test_bit(R5_Wantfill, &sh->dev[i].flags) &&
3414                     s->failed > conf->max_degraded &&
3415                     (!test_bit(R5_Insync, &sh->dev[i].flags) ||
3416                       test_bit(R5_ReadError, &sh->dev[i].flags))) {
3417                         spin_lock_irq(&sh->stripe_lock);
3418                         bi = sh->dev[i].toread;
3419                         sh->dev[i].toread = NULL;
3420                         spin_unlock_irq(&sh->stripe_lock);
3421                         if (test_and_clear_bit(R5_Overlap, &sh->dev[i].flags))
3422                                 wake_up(&conf->wait_for_overlap);
3423                         if (bi)
3424                                 s->to_read--;
3425                         while (bi && bi->bi_iter.bi_sector <
3426                                sh->dev[i].sector + STRIPE_SECTORS) {
3427                                 struct bio *nextbi =
3428                                         r5_next_bio(bi, sh->dev[i].sector);
3429
3430                                 bio_io_error(bi);
3431                                 bi = nextbi;
3432                         }
3433                 }
3434                 if (bitmap_end)
3435                         bitmap_endwrite(conf->mddev->bitmap, sh->sector,
3436                                         STRIPE_SECTORS, 0, 0);
3437                 /* If we were in the middle of a write the parity block might
3438                  * still be locked - so just clear all R5_LOCKED flags
3439                  */
3440                 clear_bit(R5_LOCKED, &sh->dev[i].flags);
3441         }
3442         s->to_write = 0;
3443         s->written = 0;
3444
3445         if (test_and_clear_bit(STRIPE_FULL_WRITE, &sh->state))
3446                 if (atomic_dec_and_test(&conf->pending_full_writes))
3447                         md_wakeup_thread(conf->mddev->thread);
3448 }
3449
3450 static void
3451 handle_failed_sync(struct r5conf *conf, struct stripe_head *sh,
3452                    struct stripe_head_state *s)
3453 {
3454         int abort = 0;
3455         int i;
3456
3457         BUG_ON(sh->batch_head);
3458         clear_bit(STRIPE_SYNCING, &sh->state);
3459         if (test_and_clear_bit(R5_Overlap, &sh->dev[sh->pd_idx].flags))
3460                 wake_up(&conf->wait_for_overlap);
3461         s->syncing = 0;
3462         s->replacing = 0;
3463         /* There is nothing more to do for sync/check/repair.
3464          * Don't even need to abort as that is handled elsewhere
3465          * if needed, and not always wanted e.g. if there is a known
3466          * bad block here.
3467          * For recover/replace we need to record a bad block on all
3468          * non-sync devices, or abort the recovery
3469          */
3470         if (test_bit(MD_RECOVERY_RECOVER, &conf->mddev->recovery)) {
3471                 /* During recovery devices cannot be removed, so
3472                  * locking and refcounting of rdevs is not needed
3473                  */
3474                 rcu_read_lock();
3475                 for (i = 0; i < conf->raid_disks; i++) {
3476                         struct md_rdev *rdev = rcu_dereference(conf->disks[i].rdev);
3477                         if (rdev
3478                             && !test_bit(Faulty, &rdev->flags)
3479                             && !test_bit(In_sync, &rdev->flags)
3480                             && !rdev_set_badblocks(rdev, sh->sector,
3481                                                    STRIPE_SECTORS, 0))
3482                                 abort = 1;
3483                         rdev = rcu_dereference(conf->disks[i].replacement);
3484                         if (rdev
3485                             && !test_bit(Faulty, &rdev->flags)
3486                             && !test_bit(In_sync, &rdev->flags)
3487                             && !rdev_set_badblocks(rdev, sh->sector,
3488                                                    STRIPE_SECTORS, 0))
3489                                 abort = 1;
3490                 }
3491                 rcu_read_unlock();
3492                 if (abort)
3493                         conf->recovery_disabled =
3494                                 conf->mddev->recovery_disabled;
3495         }
3496         md_done_sync(conf->mddev, STRIPE_SECTORS, !abort);
3497 }
3498
3499 static int want_replace(struct stripe_head *sh, int disk_idx)
3500 {
3501         struct md_rdev *rdev;
3502         int rv = 0;
3503
3504         rcu_read_lock();
3505         rdev = rcu_dereference(sh->raid_conf->disks[disk_idx].replacement);
3506         if (rdev
3507             && !test_bit(Faulty, &rdev->flags)
3508             && !test_bit(In_sync, &rdev->flags)
3509             && (rdev->recovery_offset <= sh->sector
3510                 || rdev->mddev->recovery_cp <= sh->sector))
3511                 rv = 1;
3512         rcu_read_unlock();
3513         return rv;
3514 }
3515
3516 static int need_this_block(struct stripe_head *sh, struct stripe_head_state *s,
3517                            int disk_idx, int disks)
3518 {
3519         struct r5dev *dev = &sh->dev[disk_idx];
3520         struct r5dev *fdev[2] = { &sh->dev[s->failed_num[0]],
3521                                   &sh->dev[s->failed_num[1]] };
3522         int i;
3523
3524
3525         if (test_bit(R5_LOCKED, &dev->flags) ||
3526             test_bit(R5_UPTODATE, &dev->flags))
3527                 /* No point reading this as we already have it or have
3528                  * decided to get it.
3529                  */
3530                 return 0;
3531
3532         if (dev->toread ||
3533             (dev->towrite && !test_bit(R5_OVERWRITE, &dev->flags)))
3534                 /* We need this block to directly satisfy a request */
3535                 return 1;
3536
3537         if (s->syncing || s->expanding ||
3538             (s->replacing && want_replace(sh, disk_idx)))
3539                 /* When syncing, or expanding we read everything.
3540                  * When replacing, we need the replaced block.
3541                  */
3542                 return 1;
3543
3544         if ((s->failed >= 1 && fdev[0]->toread) ||
3545             (s->failed >= 2 && fdev[1]->toread))
3546                 /* If we want to read from a failed device, then
3547                  * we need to actually read every other device.
3548                  */
3549                 return 1;
3550
3551         /* Sometimes neither read-modify-write nor reconstruct-write
3552          * cycles can work.  In those cases we read every block we
3553          * can.  Then the parity-update is certain to have enough to
3554          * work with.
3555          * This can only be a problem when we need to write something,
3556          * and some device has failed.  If either of those tests
3557          * fail we need look no further.
3558          */
3559         if (!s->failed || !s->to_write)
3560                 return 0;
3561
3562         if (test_bit(R5_Insync, &dev->flags) &&
3563             !test_bit(STRIPE_PREREAD_ACTIVE, &sh->state))
3564                 /* Pre-reads at not permitted until after short delay
3565                  * to gather multiple requests.  However if this
3566                  * device is no Insync, the block could only be computed
3567                  * and there is no need to delay that.
3568                  */
3569                 return 0;
3570
3571         for (i = 0; i < s->failed && i < 2; i++) {
3572                 if (fdev[i]->towrite &&
3573                     !test_bit(R5_UPTODATE, &fdev[i]->flags) &&
3574                     !test_bit(R5_OVERWRITE, &fdev[i]->flags))
3575                         /* If we have a partial write to a failed
3576                          * device, then we will need to reconstruct
3577                          * the content of that device, so all other
3578                          * devices must be read.
3579                          */
3580                         return 1;
3581         }
3582
3583         /* If we are forced to do a reconstruct-write, either because
3584          * the current RAID6 implementation only supports that, or
3585          * because parity cannot be trusted and we are currently
3586          * recovering it, there is extra need to be careful.
3587          * If one of the devices that we would need to read, because
3588          * it is not being overwritten (and maybe not written at all)
3589          * is missing/faulty, then we need to read everything we can.
3590          */
3591         if (sh->raid_conf->level != 6 &&
3592             sh->sector < sh->raid_conf->mddev->recovery_cp)
3593                 /* reconstruct-write isn't being forced */
3594                 return 0;
3595         for (i = 0; i < s->failed && i < 2; i++) {
3596                 if (s->failed_num[i] != sh->pd_idx &&
3597                     s->failed_num[i] != sh->qd_idx &&
3598                     !test_bit(R5_UPTODATE, &fdev[i]->flags) &&
3599                     !test_bit(R5_OVERWRITE, &fdev[i]->flags))
3600                         return 1;
3601         }
3602
3603         return 0;
3604 }
3605
3606 /* fetch_block - checks the given member device to see if its data needs
3607  * to be read or computed to satisfy a request.
3608  *
3609  * Returns 1 when no more member devices need to be checked, otherwise returns
3610  * 0 to tell the loop in handle_stripe_fill to continue
3611  */
3612 static int fetch_block(struct stripe_head *sh, struct stripe_head_state *s,
3613                        int disk_idx, int disks)
3614 {
3615         struct r5dev *dev = &sh->dev[disk_idx];
3616
3617         /* is the data in this block needed, and can we get it? */
3618         if (need_this_block(sh, s, disk_idx, disks)) {
3619                 /* we would like to get this block, possibly by computing it,
3620                  * otherwise read it if the backing disk is insync
3621                  */
3622                 BUG_ON(test_bit(R5_Wantcompute, &dev->flags));
3623                 BUG_ON(test_bit(R5_Wantread, &dev->flags));
3624                 BUG_ON(sh->batch_head);
3625
3626                 /*
3627                  * In the raid6 case if the only non-uptodate disk is P
3628                  * then we already trusted P to compute the other failed
3629                  * drives. It is safe to compute rather than re-read P.
3630                  * In other cases we only compute blocks from failed
3631                  * devices, otherwise check/repair might fail to detect
3632                  * a real inconsistency.
3633                  */
3634
3635                 if ((s->uptodate == disks - 1) &&
3636                     ((sh->qd_idx >= 0 && sh->pd_idx == disk_idx) ||
3637                     (s->failed && (disk_idx == s->failed_num[0] ||
3638                                    disk_idx == s->failed_num[1])))) {
3639                         /* have disk failed, and we're requested to fetch it;
3640                          * do compute it
3641                          */
3642                         pr_debug("Computing stripe %llu block %d\n",
3643                                (unsigned long long)sh->sector, disk_idx);
3644                         set_bit(STRIPE_COMPUTE_RUN, &sh->state);
3645                         set_bit(STRIPE_OP_COMPUTE_BLK, &s->ops_request);
3646                         set_bit(R5_Wantcompute, &dev->flags);
3647                         sh->ops.target = disk_idx;
3648                         sh->ops.target2 = -1; /* no 2nd target */
3649                         s->req_compute = 1;
3650                         /* Careful: from this point on 'uptodate' is in the eye
3651                          * of raid_run_ops which services 'compute' operations
3652                          * before writes. R5_Wantcompute flags a block that will
3653                          * be R5_UPTODATE by the time it is needed for a
3654                          * subsequent operation.
3655                          */
3656                         s->uptodate++;
3657                         return 1;
3658                 } else if (s->uptodate == disks-2 && s->failed >= 2) {
3659                         /* Computing 2-failure is *very* expensive; only
3660                          * do it if failed >= 2
3661                          */
3662                         int other;
3663                         for (other = disks; other--; ) {
3664                                 if (other == disk_idx)
3665                                         continue;
3666                                 if (!test_bit(R5_UPTODATE,
3667                                       &sh->dev[other].flags))
3668                                         break;
3669                         }
3670                         BUG_ON(other < 0);
3671                         pr_debug("Computing stripe %llu blocks %d,%d\n",
3672                                (unsigned long long)sh->sector,
3673                                disk_idx, other);
3674                         set_bit(STRIPE_COMPUTE_RUN, &sh->state);
3675                         set_bit(STRIPE_OP_COMPUTE_BLK, &s->ops_request);
3676                         set_bit(R5_Wantcompute, &sh->dev[disk_idx].flags);
3677                         set_bit(R5_Wantcompute, &sh->dev[other].flags);
3678                         sh->ops.target = disk_idx;
3679                         sh->ops.target2 = other;
3680                         s->uptodate += 2;
3681                         s->req_compute = 1;
3682                         return 1;
3683                 } else if (test_bit(R5_Insync, &dev->flags)) {
3684                         set_bit(R5_LOCKED, &dev->flags);
3685                         set_bit(R5_Wantread, &dev->flags);
3686                         s->locked++;
3687                         pr_debug("Reading block %d (sync=%d)\n",
3688                                 disk_idx, s->syncing);
3689                 }
3690         }
3691
3692         return 0;
3693 }
3694
3695 /**
3696  * handle_stripe_fill - read or compute data to satisfy pending requests.
3697  */
3698 static void handle_stripe_fill(struct stripe_head *sh,
3699                                struct stripe_head_state *s,
3700                                int disks)
3701 {
3702         int i;
3703
3704         /* look for blocks to read/compute, skip this if a compute
3705          * is already in flight, or if the stripe contents are in the
3706          * midst of changing due to a write
3707          */
3708         if (!test_bit(STRIPE_COMPUTE_RUN, &sh->state) && !sh->check_state &&
3709             !sh->reconstruct_state) {
3710
3711                 /*
3712                  * For degraded stripe with data in journal, do not handle
3713                  * read requests yet, instead, flush the stripe to raid
3714                  * disks first, this avoids handling complex rmw of write
3715                  * back cache (prexor with orig_page, and then xor with
3716                  * page) in the read path
3717                  */
3718                 if (s->injournal && s->failed) {
3719                         if (test_bit(STRIPE_R5C_CACHING, &sh->state))
3720                                 r5c_make_stripe_write_out(sh);
3721                         goto out;
3722                 }
3723
3724                 for (i = disks; i--; )
3725                         if (fetch_block(sh, s, i, disks))
3726                                 break;
3727         }
3728 out:
3729         set_bit(STRIPE_HANDLE, &sh->state);
3730 }
3731
3732 static void break_stripe_batch_list(struct stripe_head *head_sh,
3733                                     unsigned long handle_flags);
3734 /* handle_stripe_clean_event
3735  * any written block on an uptodate or failed drive can be returned.
3736  * Note that if we 'wrote' to a failed drive, it will be UPTODATE, but
3737  * never LOCKED, so we don't need to test 'failed' directly.
3738  */
3739 static void handle_stripe_clean_event(struct r5conf *conf,
3740         struct stripe_head *sh, int disks)
3741 {
3742         int i;
3743         struct r5dev *dev;
3744         int discard_pending = 0;
3745         struct stripe_head *head_sh = sh;
3746         bool do_endio = false;
3747
3748         for (i = disks; i--; )
3749                 if (sh->dev[i].written) {
3750                         dev = &sh->dev[i];
3751                         if (!test_bit(R5_LOCKED, &dev->flags) &&
3752                             (test_bit(R5_UPTODATE, &dev->flags) ||
3753                              test_bit(R5_Discard, &dev->flags) ||
3754                              test_bit(R5_SkipCopy, &dev->flags))) {
3755                                 /* We can return any write requests */
3756                                 struct bio *wbi, *wbi2;
3757                                 pr_debug("Return write for disc %d\n", i);
3758                                 if (test_and_clear_bit(R5_Discard, &dev->flags))
3759                                         clear_bit(R5_UPTODATE, &dev->flags);
3760                                 if (test_and_clear_bit(R5_SkipCopy, &dev->flags)) {
3761                                         WARN_ON(test_bit(R5_UPTODATE, &dev->flags));
3762                                 }
3763                                 do_endio = true;
3764
3765 returnbi:
3766                                 dev->page = dev->orig_page;
3767                                 wbi = dev->written;
3768                                 dev->written = NULL;
3769                                 while (wbi && wbi->bi_iter.bi_sector <
3770                                         dev->sector + STRIPE_SECTORS) {
3771                                         wbi2 = r5_next_bio(wbi, dev->sector);
3772                                         md_write_end(conf->mddev);
3773                                         bio_endio(wbi);
3774                                         wbi = wbi2;
3775                                 }
3776                                 bitmap_endwrite(conf->mddev->bitmap, sh->sector,
3777                                                 STRIPE_SECTORS,
3778                                          !test_bit(STRIPE_DEGRADED, &sh->state),
3779                                                 0);
3780                                 if (head_sh->batch_head) {
3781                                         sh = list_first_entry(&sh->batch_list,
3782                                                               struct stripe_head,
3783                                                               batch_list);
3784                                         if (sh != head_sh) {
3785                                                 dev = &sh->dev[i];
3786                                                 goto returnbi;
3787                                         }
3788                                 }
3789                                 sh = head_sh;
3790                                 dev = &sh->dev[i];
3791                         } else if (test_bit(R5_Discard, &dev->flags))
3792                                 discard_pending = 1;
3793                 }
3794
3795         log_stripe_write_finished(sh);
3796
3797         if (!discard_pending &&
3798             test_bit(R5_Discard, &sh->dev[sh->pd_idx].flags)) {
3799                 int hash;
3800                 clear_bit(R5_Discard, &sh->dev[sh->pd_idx].flags);
3801                 clear_bit(R5_UPTODATE, &sh->dev[sh->pd_idx].flags);
3802                 if (sh->qd_idx >= 0) {
3803                         clear_bit(R5_Discard, &sh->dev[sh->qd_idx].flags);
3804                         clear_bit(R5_UPTODATE, &sh->dev[sh->qd_idx].flags);
3805                 }
3806                 /* now that discard is done we can proceed with any sync */
3807                 clear_bit(STRIPE_DISCARD, &sh->state);
3808                 /*
3809                  * SCSI discard will change some bio fields and the stripe has
3810                  * no updated data, so remove it from hash list and the stripe
3811                  * will be reinitialized
3812                  */
3813 unhash:
3814                 hash = sh->hash_lock_index;
3815                 spin_lock_irq(conf->hash_locks + hash);
3816                 remove_hash(sh);
3817                 spin_unlock_irq(conf->hash_locks + hash);
3818                 if (head_sh->batch_head) {
3819                         sh = list_first_entry(&sh->batch_list,
3820                                               struct stripe_head, batch_list);
3821                         if (sh != head_sh)
3822                                         goto unhash;
3823                 }
3824                 sh = head_sh;
3825
3826                 if (test_bit(STRIPE_SYNC_REQUESTED, &sh->state))
3827                         set_bit(STRIPE_HANDLE, &sh->state);
3828
3829         }
3830
3831         if (test_and_clear_bit(STRIPE_FULL_WRITE, &sh->state))
3832                 if (atomic_dec_and_test(&conf->pending_full_writes))
3833                         md_wakeup_thread(conf->mddev->thread);
3834
3835         if (head_sh->batch_head && do_endio)
3836                 break_stripe_batch_list(head_sh, STRIPE_EXPAND_SYNC_FLAGS);
3837 }
3838
3839 /*
3840  * For RMW in write back cache, we need extra page in prexor to store the
3841  * old data. This page is stored in dev->orig_page.
3842  *
3843  * This function checks whether we have data for prexor. The exact logic
3844  * is:
3845  *       R5_UPTODATE && (!R5_InJournal || R5_OrigPageUPTDODATE)
3846  */
3847 static inline bool uptodate_for_rmw(struct r5dev *dev)
3848 {
3849         return (test_bit(R5_UPTODATE, &dev->flags)) &&
3850                 (!test_bit(R5_InJournal, &dev->flags) ||
3851                  test_bit(R5_OrigPageUPTDODATE, &dev->flags));
3852 }
3853
3854 static int handle_stripe_dirtying(struct r5conf *conf,
3855                                   struct stripe_head *sh,
3856                                   struct stripe_head_state *s,
3857                                   int disks)
3858 {
3859         int rmw = 0, rcw = 0, i;
3860         sector_t recovery_cp = conf->mddev->recovery_cp;
3861
3862         /* Check whether resync is now happening or should start.
3863          * If yes, then the array is dirty (after unclean shutdown or
3864          * initial creation), so parity in some stripes might be inconsistent.
3865          * In this case, we need to always do reconstruct-write, to ensure
3866          * that in case of drive failure or read-error correction, we
3867          * generate correct data from the parity.
3868          */
3869         if (conf->rmw_level == PARITY_DISABLE_RMW ||
3870             (recovery_cp < MaxSector && sh->sector >= recovery_cp &&
3871              s->failed == 0)) {
3872                 /* Calculate the real rcw later - for now make it
3873                  * look like rcw is cheaper
3874                  */
3875                 rcw = 1; rmw = 2;
3876                 pr_debug("force RCW rmw_level=%u, recovery_cp=%llu sh->sector=%llu\n",
3877                          conf->rmw_level, (unsigned long long)recovery_cp,
3878                          (unsigned long long)sh->sector);
3879         } else for (i = disks; i--; ) {
3880                 /* would I have to read this buffer for read_modify_write */
3881                 struct r5dev *dev = &sh->dev[i];
3882                 if (((dev->towrite && !delay_towrite(conf, dev, s)) ||
3883                      i == sh->pd_idx || i == sh->qd_idx ||
3884                      test_bit(R5_InJournal, &dev->flags)) &&
3885                     !test_bit(R5_LOCKED, &dev->flags) &&
3886                     !(uptodate_for_rmw(dev) ||
3887                       test_bit(R5_Wantcompute, &dev->flags))) {
3888                         if (test_bit(R5_Insync, &dev->flags))
3889                                 rmw++;
3890                         else
3891                                 rmw += 2*disks;  /* cannot read it */
3892                 }
3893                 /* Would I have to read this buffer for reconstruct_write */
3894                 if (!test_bit(R5_OVERWRITE, &dev->flags) &&
3895                     i != sh->pd_idx && i != sh->qd_idx &&
3896                     !test_bit(R5_LOCKED, &dev->flags) &&
3897                     !(test_bit(R5_UPTODATE, &dev->flags) ||
3898                       test_bit(R5_Wantcompute, &dev->flags))) {
3899                         if (test_bit(R5_Insync, &dev->flags))
3900                                 rcw++;
3901                         else
3902                                 rcw += 2*disks;
3903                 }
3904         }
3905
3906         pr_debug("for sector %llu state 0x%lx, rmw=%d rcw=%d\n",
3907                  (unsigned long long)sh->sector, sh->state, rmw, rcw);
3908         set_bit(STRIPE_HANDLE, &sh->state);
3909         if ((rmw < rcw || (rmw == rcw && conf->rmw_level == PARITY_PREFER_RMW)) && rmw > 0) {
3910                 /* prefer read-modify-write, but need to get some data */
3911                 if (conf->mddev->queue)
3912                         blk_add_trace_msg(conf->mddev->queue,
3913                                           "raid5 rmw %llu %d",
3914                                           (unsigned long long)sh->sector, rmw);
3915                 for (i = disks; i--; ) {
3916                         struct r5dev *dev = &sh->dev[i];
3917                         if (test_bit(R5_InJournal, &dev->flags) &&
3918                             dev->page == dev->orig_page &&
3919                             !test_bit(R5_LOCKED, &sh->dev[sh->pd_idx].flags)) {
3920                                 /* alloc page for prexor */
3921                                 struct page *p = alloc_page(GFP_NOIO);
3922
3923                                 if (p) {
3924                                         dev->orig_page = p;
3925                                         continue;
3926                                 }
3927
3928                                 /*
3929                                  * alloc_page() failed, try use
3930                                  * disk_info->extra_page
3931                                  */
3932                                 if (!test_and_set_bit(R5C_EXTRA_PAGE_IN_USE,
3933                                                       &conf->cache_state)) {
3934                                         r5c_use_extra_page(sh);
3935                                         break;
3936                                 }
3937
3938                                 /* extra_page in use, add to delayed_list */
3939                                 set_bit(STRIPE_DELAYED, &sh->state);
3940                                 s->waiting_extra_page = 1;
3941                                 return -EAGAIN;
3942                         }
3943                 }
3944
3945                 for (i = disks; i--; ) {
3946                         struct r5dev *dev = &sh->dev[i];
3947                         if (((dev->towrite && !delay_towrite(conf, dev, s)) ||
3948                              i == sh->pd_idx || i == sh->qd_idx ||
3949                              test_bit(R5_InJournal, &dev->flags)) &&
3950                             !test_bit(R5_LOCKED, &dev->flags) &&
3951                             !(uptodate_for_rmw(dev) ||
3952                               test_bit(R5_Wantcompute, &dev->flags)) &&
3953                             test_bit(R5_Insync, &dev->flags)) {
3954                                 if (test_bit(STRIPE_PREREAD_ACTIVE,
3955                                              &sh->state)) {
3956                                         pr_debug("Read_old block %d for r-m-w\n",
3957                                                  i);
3958                                         set_bit(R5_LOCKED, &dev->flags);
3959                                         set_bit(R5_Wantread, &dev->flags);
3960                                         s->locked++;
3961                                 } else {
3962                                         set_bit(STRIPE_DELAYED, &sh->state);
3963                                         set_bit(STRIPE_HANDLE, &sh->state);
3964                                 }
3965                         }
3966                 }
3967         }
3968         if ((rcw < rmw || (rcw == rmw && conf->rmw_level != PARITY_PREFER_RMW)) && rcw > 0) {
3969                 /* want reconstruct write, but need to get some data */
3970                 int qread =0;
3971                 rcw = 0;
3972                 for (i = disks; i--; ) {
3973                         struct r5dev *dev = &sh->dev[i];
3974                         if (!test_bit(R5_OVERWRITE, &dev->flags) &&
3975                             i != sh->pd_idx && i != sh->qd_idx &&
3976                             !test_bit(R5_LOCKED, &dev->flags) &&
3977                             !(test_bit(R5_UPTODATE, &dev->flags) ||
3978                               test_bit(R5_Wantcompute, &dev->flags))) {
3979                                 rcw++;
3980                                 if (test_bit(R5_Insync, &dev->flags) &&
3981                                     test_bit(STRIPE_PREREAD_ACTIVE,
3982                                              &sh->state)) {
3983                                         pr_debug("Read_old block "
3984                                                 "%d for Reconstruct\n", i);
3985                                         set_bit(R5_LOCKED, &dev->flags);
3986                                         set_bit(R5_Wantread, &dev->flags);
3987                                         s->locked++;
3988                                         qread++;
3989                                 } else {
3990                                         set_bit(STRIPE_DELAYED, &sh->state);
3991                                         set_bit(STRIPE_HANDLE, &sh->state);
3992                                 }
3993                         }
3994                 }
3995                 if (rcw && conf->mddev->queue)
3996                         blk_add_trace_msg(conf->mddev->queue, "raid5 rcw %llu %d %d %d",
3997                                           (unsigned long long)sh->sector,
3998                                           rcw, qread, test_bit(STRIPE_DELAYED, &sh->state));
3999         }
4000
4001         if (rcw > disks && rmw > disks &&
4002             !test_bit(STRIPE_PREREAD_ACTIVE, &sh->state))
4003                 set_bit(STRIPE_DELAYED, &sh->state);
4004
4005         /* now if nothing is locked, and if we have enough data,
4006          * we can start a write request
4007          */
4008         /* since handle_stripe can be called at any time we need to handle the
4009          * case where a compute block operation has been submitted and then a
4010          * subsequent call wants to start a write request.  raid_run_ops only
4011          * handles the case where compute block and reconstruct are requested
4012          * simultaneously.  If this is not the case then new writes need to be
4013          * held off until the compute completes.
4014          */
4015         if ((s->req_compute || !test_bit(STRIPE_COMPUTE_RUN, &sh->state)) &&
4016             (s->locked == 0 && (rcw == 0 || rmw == 0) &&
4017              !test_bit(STRIPE_BIT_DELAY, &sh->state)))
4018                 schedule_reconstruction(sh, s, rcw == 0, 0);
4019         return 0;
4020 }
4021
4022 static void handle_parity_checks5(struct r5conf *conf, struct stripe_head *sh,
4023                                 struct stripe_head_state *s, int disks)
4024 {
4025         struct r5dev *dev = NULL;
4026
4027         BUG_ON(sh->batch_head);
4028         set_bit(STRIPE_HANDLE, &sh->state);
4029
4030         switch (sh->check_state) {
4031         case check_state_idle:
4032                 /* start a new check operation if there are no failures */
4033                 if (s->failed == 0) {
4034                         BUG_ON(s->uptodate != disks);
4035                         sh->check_state = check_state_run;
4036                         set_bit(STRIPE_OP_CHECK, &s->ops_request);
4037                         clear_bit(R5_UPTODATE, &sh->dev[sh->pd_idx].flags);
4038                         s->uptodate--;
4039                         break;
4040                 }
4041                 dev = &sh->dev[s->failed_num[0]];
4042                 /* fall through */
4043         case check_state_compute_result:
4044                 sh->check_state = check_state_idle;
4045                 if (!dev)
4046                         dev = &sh->dev[sh->pd_idx];
4047
4048                 /* check that a write has not made the stripe insync */
4049                 if (test_bit(STRIPE_INSYNC, &sh->state))
4050                         break;
4051
4052                 /* either failed parity check, or recovery is happening */
4053                 BUG_ON(!test_bit(R5_UPTODATE, &dev->flags));
4054                 BUG_ON(s->uptodate != disks);
4055
4056                 set_bit(R5_LOCKED, &dev->flags);
4057                 s->locked++;
4058                 set_bit(R5_Wantwrite, &dev->flags);
4059
4060                 clear_bit(STRIPE_DEGRADED, &sh->state);
4061                 set_bit(STRIPE_INSYNC, &sh->state);
4062                 break;
4063         case check_state_run:
4064                 break; /* we will be called again upon completion */
4065         case check_state_check_result:
4066                 sh->check_state = check_state_idle;
4067
4068                 /* if a failure occurred during the check operation, leave
4069                  * STRIPE_INSYNC not set and let the stripe be handled again
4070                  */
4071                 if (s->failed)
4072                         break;
4073
4074                 /* handle a successful check operation, if parity is correct
4075                  * we are done.  Otherwise update the mismatch count and repair
4076                  * parity if !MD_RECOVERY_CHECK
4077                  */
4078                 if ((sh->ops.zero_sum_result & SUM_CHECK_P_RESULT) == 0)
4079                         /* parity is correct (on disc,
4080                          * not in buffer any more)
4081                          */
4082                         set_bit(STRIPE_INSYNC, &sh->state);
4083                 else {
4084                         atomic64_add(STRIPE_SECTORS, &conf->mddev->resync_mismatches);
4085                         if (test_bit(MD_RECOVERY_CHECK, &conf->mddev->recovery)) {
4086                                 /* don't try to repair!! */
4087                                 set_bit(STRIPE_INSYNC, &sh->state);
4088                                 pr_warn_ratelimited("%s: mismatch sector in range "
4089                                                     "%llu-%llu\n", mdname(conf->mddev),
4090                                                     (unsigned long long) sh->sector,
4091                                                     (unsigned long long) sh->sector +
4092                                                     STRIPE_SECTORS);
4093                         } else {
4094                                 sh->check_state = check_state_compute_run;
4095                                 set_bit(STRIPE_COMPUTE_RUN, &sh->state);
4096                                 set_bit(STRIPE_OP_COMPUTE_BLK, &s->ops_request);
4097                                 set_bit(R5_Wantcompute,
4098                                         &sh->dev[sh->pd_idx].flags);
4099                                 sh->ops.target = sh->pd_idx;
4100                                 sh->ops.target2 = -1;
4101                                 s->uptodate++;
4102                         }
4103                 }
4104                 break;
4105         case check_state_compute_run:
4106                 break;
4107         default:
4108                 pr_err("%s: unknown check_state: %d sector: %llu\n",
4109                        __func__, sh->check_state,
4110                        (unsigned long long) sh->sector);
4111                 BUG();
4112         }
4113 }
4114
4115 static void handle_parity_checks6(struct r5conf *conf, struct stripe_head *sh,
4116                                   struct stripe_head_state *s,
4117                                   int disks)
4118 {
4119         int pd_idx = sh->pd_idx;
4120         int qd_idx = sh->qd_idx;
4121         struct r5dev *dev;
4122
4123         BUG_ON(sh->batch_head);
4124         set_bit(STRIPE_HANDLE, &sh->state);
4125
4126         BUG_ON(s->failed > 2);
4127
4128         /* Want to check and possibly repair P and Q.
4129          * However there could be one 'failed' device, in which
4130          * case we can only check one of them, possibly using the
4131          * other to generate missing data
4132          */
4133
4134         switch (sh->check_state) {
4135         case check_state_idle:
4136                 /* start a new check operation if there are < 2 failures */
4137                 if (s->failed == s->q_failed) {
4138                         /* The only possible failed device holds Q, so it
4139                          * makes sense to check P (If anything else were failed,
4140                          * we would have used P to recreate it).
4141                          */
4142                         sh->check_state = check_state_run;
4143                 }
4144                 if (!s->q_failed && s->failed < 2) {
4145                         /* Q is not failed, and we didn't use it to generate
4146                          * anything, so it makes sense to check it
4147                          */
4148                         if (sh->check_state == check_state_run)
4149                                 sh->check_state = check_state_run_pq;
4150                         else
4151                                 sh->check_state = check_state_run_q;
4152                 }
4153
4154                 /* discard potentially stale zero_sum_result */
4155                 sh->ops.zero_sum_result = 0;
4156
4157                 if (sh->check_state == check_state_run) {
4158                         /* async_xor_zero_sum destroys the contents of P */
4159                         clear_bit(R5_UPTODATE, &sh->dev[pd_idx].flags);
4160                         s->uptodate--;
4161                 }
4162                 if (sh->check_state >= check_state_run &&
4163                     sh->check_state <= check_state_run_pq) {
4164                         /* async_syndrome_zero_sum preserves P and Q, so
4165                          * no need to mark them !uptodate here
4166                          */
4167                         set_bit(STRIPE_OP_CHECK, &s->ops_request);
4168                         break;
4169                 }
4170
4171                 /* we have 2-disk failure */
4172                 BUG_ON(s->failed != 2);
4173                 /* fall through */
4174         case check_state_compute_result:
4175                 sh->check_state = check_state_idle;
4176
4177                 /* check that a write has not made the stripe insync */
4178                 if (test_bit(STRIPE_INSYNC, &sh->state))
4179                         break;
4180
4181                 /* now write out any block on a failed drive,
4182                  * or P or Q if they were recomputed
4183                  */
4184                 BUG_ON(s->uptodate < disks - 1); /* We don't need Q to recover */
4185                 if (s->failed == 2) {
4186                         dev = &sh->dev[s->failed_num[1]];
4187                         s->locked++;
4188                         set_bit(R5_LOCKED, &dev->flags);
4189                         set_bit(R5_Wantwrite, &dev->flags);
4190                 }
4191                 if (s->failed >= 1) {
4192                         dev = &sh->dev[s->failed_num[0]];
4193                         s->locked++;
4194                         set_bit(R5_LOCKED, &dev->flags);
4195                         set_bit(R5_Wantwrite, &dev->flags);
4196                 }
4197                 if (sh->ops.zero_sum_result & SUM_CHECK_P_RESULT) {
4198                         dev = &sh->dev[pd_idx];
4199                         s->locked++;
4200                         set_bit(R5_LOCKED, &dev->flags);
4201                         set_bit(R5_Wantwrite, &dev->flags);
4202                 }
4203                 if (sh->ops.zero_sum_result & SUM_CHECK_Q_RESULT) {
4204                         dev = &sh->dev[qd_idx];
4205                         s->locked++;
4206                         set_bit(R5_LOCKED, &dev->flags);
4207                         set_bit(R5_Wantwrite, &dev->flags);
4208                 }
4209                 clear_bit(STRIPE_DEGRADED, &sh->state);
4210
4211                 set_bit(STRIPE_INSYNC, &sh->state);
4212                 break;
4213         case check_state_run:
4214         case check_state_run_q:
4215         case check_state_run_pq:
4216                 break; /* we will be called again upon completion */
4217         case check_state_check_result:
4218                 sh->check_state = check_state_idle;
4219
4220                 /* handle a successful check operation, if parity is correct
4221                  * we are done.  Otherwise update the mismatch count and repair
4222                  * parity if !MD_RECOVERY_CHECK
4223                  */
4224                 if (sh->ops.zero_sum_result == 0) {
4225                         /* both parities are correct */
4226                         if (!s->failed)
4227                                 set_bit(STRIPE_INSYNC, &sh->state);
4228                         else {
4229                                 /* in contrast to the raid5 case we can validate
4230                                  * parity, but still have a failure to write
4231                                  * back
4232                                  */
4233                                 sh->check_state = check_state_compute_result;
4234                                 /* Returning at this point means that we may go
4235                                  * off and bring p and/or q uptodate again so
4236                                  * we make sure to check zero_sum_result again
4237                                  * to verify if p or q need writeback
4238                                  */
4239                         }
4240                 } else {
4241                         atomic64_add(STRIPE_SECTORS, &conf->mddev->resync_mismatches);
4242                         if (test_bit(MD_RECOVERY_CHECK, &conf->mddev->recovery)) {
4243                                 /* don't try to repair!! */
4244                                 set_bit(STRIPE_INSYNC, &sh->state);
4245                                 pr_warn_ratelimited("%s: mismatch sector in range "
4246                                                     "%llu-%llu\n", mdname(conf->mddev),
4247                                                     (unsigned long long) sh->sector,
4248                                                     (unsigned long long) sh->sector +
4249                                                     STRIPE_SECTORS);
4250                         } else {
4251                                 int *target = &sh->ops.target;
4252
4253                                 sh->ops.target = -1;
4254                                 sh->ops.target2 = -1;
4255                                 sh->check_state = check_state_compute_run;
4256                                 set_bit(STRIPE_COMPUTE_RUN, &sh->state);
4257                                 set_bit(STRIPE_OP_COMPUTE_BLK, &s->ops_request);
4258                                 if (sh->ops.zero_sum_result & SUM_CHECK_P_RESULT) {
4259                                         set_bit(R5_Wantcompute,
4260                                                 &sh->dev[pd_idx].flags);
4261                                         *target = pd_idx;
4262                                         target = &sh->ops.target2;
4263                                         s->uptodate++;
4264                                 }
4265                                 if (sh->ops.zero_sum_result & SUM_CHECK_Q_RESULT) {
4266                                         set_bit(R5_Wantcompute,
4267                                                 &sh->dev[qd_idx].flags);
4268                                         *target = qd_idx;
4269                                         s->uptodate++;
4270                                 }
4271                         }
4272                 }
4273                 break;
4274         case check_state_compute_run:
4275                 break;
4276         default:
4277                 pr_warn("%s: unknown check_state: %d sector: %llu\n",
4278                         __func__, sh->check_state,
4279                         (unsigned long long) sh->sector);
4280                 BUG();
4281         }
4282 }
4283
4284 static void handle_stripe_expansion(struct r5conf *conf, struct stripe_head *sh)
4285 {
4286         int i;
4287
4288         /* We have read all the blocks in this stripe and now we need to
4289          * copy some of them into a target stripe for expand.
4290          */
4291         struct dma_async_tx_descriptor *tx = NULL;
4292         BUG_ON(sh->batch_head);
4293         clear_bit(STRIPE_EXPAND_SOURCE, &sh->state);
4294         for (i = 0; i < sh->disks; i++)
4295                 if (i != sh->pd_idx && i != sh->qd_idx) {
4296                         int dd_idx, j;
4297                         struct stripe_head *sh2;
4298                         struct async_submit_ctl submit;
4299
4300                         sector_t bn = raid5_compute_blocknr(sh, i, 1);
4301                         sector_t s = raid5_compute_sector(conf, bn, 0,
4302                                                           &dd_idx, NULL);
4303                         sh2 = raid5_get_active_stripe(conf, s, 0, 1, 1);
4304                         if (sh2 == NULL)
4305                                 /* so far only the early blocks of this stripe
4306                                  * have been requested.  When later blocks
4307                                  * get requested, we will try again
4308                                  */
4309                                 continue;
4310                         if (!test_bit(STRIPE_EXPANDING, &sh2->state) ||
4311                            test_bit(R5_Expanded, &sh2->dev[dd_idx].flags)) {
4312                                 /* must have already done this block */
4313                                 raid5_release_stripe(sh2);
4314                                 continue;
4315                         }
4316
4317                         /* place all the copies on one channel */
4318                         init_async_submit(&submit, 0, tx, NULL, NULL, NULL);
4319                         tx = async_memcpy(sh2->dev[dd_idx].page,
4320                                           sh->dev[i].page, 0, 0, STRIPE_SIZE,
4321                                           &submit);
4322
4323                         set_bit(R5_Expanded, &sh2->dev[dd_idx].flags);
4324                         set_bit(R5_UPTODATE, &sh2->dev[dd_idx].flags);
4325                         for (j = 0; j < conf->raid_disks; j++)
4326                                 if (j != sh2->pd_idx &&
4327                                     j != sh2->qd_idx &&
4328                                     !test_bit(R5_Expanded, &sh2->dev[j].flags))
4329                                         break;
4330                         if (j == conf->raid_disks) {
4331                                 set_bit(STRIPE_EXPAND_READY, &sh2->state);
4332                                 set_bit(STRIPE_HANDLE, &sh2->state);
4333                         }
4334                         raid5_release_stripe(sh2);
4335
4336                 }
4337         /* done submitting copies, wait for them to complete */
4338         async_tx_quiesce(&tx);
4339 }
4340
4341 /*
4342  * handle_stripe - do things to a stripe.
4343  *
4344  * We lock the stripe by setting STRIPE_ACTIVE and then examine the
4345  * state of various bits to see what needs to be done.
4346  * Possible results:
4347  *    return some read requests which now have data
4348  *    return some write requests which are safely on storage
4349  *    schedule a read on some buffers
4350  *    schedule a write of some buffers
4351  *    return confirmation of parity correctness
4352  *
4353  */
4354
4355 static void analyse_stripe(struct stripe_head *sh, struct stripe_head_state *s)
4356 {
4357         struct r5conf *conf = sh->raid_conf;
4358         int disks = sh->disks;
4359         struct r5dev *dev;
4360         int i;
4361         int do_recovery = 0;
4362
4363         memset(s, 0, sizeof(*s));
4364
4365         s->expanding = test_bit(STRIPE_EXPAND_SOURCE, &sh->state) && !sh->batch_head;
4366         s->expanded = test_bit(STRIPE_EXPAND_READY, &sh->state) && !sh->batch_head;
4367         s->failed_num[0] = -1;
4368         s->failed_num[1] = -1;
4369         s->log_failed = r5l_log_disk_error(conf);
4370
4371         /* Now to look around and see what can be done */
4372         rcu_read_lock();
4373         for (i=disks; i--; ) {
4374                 struct md_rdev *rdev;
4375                 sector_t first_bad;
4376                 int bad_sectors;
4377                 int is_bad = 0;
4378
4379                 dev = &sh->dev[i];
4380
4381                 pr_debug("check %d: state 0x%lx read %p write %p written %p\n",
4382                          i, dev->flags,
4383                          dev->toread, dev->towrite, dev->written);
4384                 /* maybe we can reply to a read
4385                  *
4386                  * new wantfill requests are only permitted while
4387                  * ops_complete_biofill is guaranteed to be inactive
4388                  */
4389                 if (test_bit(R5_UPTODATE, &dev->flags) && dev->toread &&
4390                     !test_bit(STRIPE_BIOFILL_RUN, &sh->state))
4391                         set_bit(R5_Wantfill, &dev->flags);
4392
4393                 /* now count some things */
4394                 if (test_bit(R5_LOCKED, &dev->flags))
4395                         s->locked++;
4396                 if (test_bit(R5_UPTODATE, &dev->flags))
4397                         s->uptodate++;
4398                 if (test_bit(R5_Wantcompute, &dev->flags)) {
4399                         s->compute++;
4400                         BUG_ON(s->compute > 2);
4401                 }
4402
4403                 if (test_bit(R5_Wantfill, &dev->flags))
4404                         s->to_fill++;
4405                 else if (dev->toread)
4406                         s->to_read++;
4407                 if (dev->towrite) {
4408                         s->to_write++;
4409                         if (!test_bit(R5_OVERWRITE, &dev->flags))
4410                                 s->non_overwrite++;
4411                 }
4412                 if (dev->written)
4413                         s->written++;
4414                 /* Prefer to use the replacement for reads, but only
4415                  * if it is recovered enough and has no bad blocks.
4416                  */
4417                 rdev = rcu_dereference(conf->disks[i].replacement);
4418                 if (rdev && !test_bit(Faulty, &rdev->flags) &&
4419                     rdev->recovery_offset >= sh->sector + STRIPE_SECTORS &&
4420                     !is_badblock(rdev, sh->sector, STRIPE_SECTORS,
4421                                  &first_bad, &bad_sectors))
4422                         set_bit(R5_ReadRepl, &dev->flags);
4423                 else {
4424                         if (rdev && !test_bit(Faulty, &rdev->flags))
4425                                 set_bit(R5_NeedReplace, &dev->flags);
4426                         else
4427                                 clear_bit(R5_NeedReplace, &dev->flags);
4428                         rdev = rcu_dereference(conf->disks[i].rdev);
4429                         clear_bit(R5_ReadRepl, &dev->flags);
4430                 }
4431                 if (rdev && test_bit(Faulty, &rdev->flags))
4432                         rdev = NULL;
4433                 if (rdev) {
4434                         is_bad = is_badblock(rdev, sh->sector, STRIPE_SECTORS,
4435                                              &first_bad, &bad_sectors);
4436                         if (s->blocked_rdev == NULL
4437                             && (test_bit(Blocked, &rdev->flags)
4438                                 || is_bad < 0)) {
4439                                 if (is_bad < 0)
4440                                         set_bit(BlockedBadBlocks,
4441                                                 &rdev->flags);
4442                                 s->blocked_rdev = rdev;
4443                                 atomic_inc(&rdev->nr_pending);
4444                         }
4445                 }
4446                 clear_bit(R5_Insync, &dev->flags);
4447                 if (!rdev)
4448                         /* Not in-sync */;
4449                 else if (is_bad) {
4450                         /* also not in-sync */
4451                         if (!test_bit(WriteErrorSeen, &rdev->flags) &&
4452                             test_bit(R5_UPTODATE, &dev->flags)) {
4453                                 /* treat as in-sync, but with a read error
4454                                  * which we can now try to correct
4455                                  */
4456                                 set_bit(R5_Insync, &dev->flags);
4457                                 set_bit(R5_ReadError, &dev->flags);
4458                         }
4459                 } else if (test_bit(In_sync, &rdev->flags))
4460                         set_bit(R5_Insync, &dev->flags);
4461                 else if (sh->sector + STRIPE_SECTORS <= rdev->recovery_offset)
4462                         /* in sync if before recovery_offset */
4463                         set_bit(R5_Insync, &dev->flags);
4464                 else if (test_bit(R5_UPTODATE, &dev->flags) &&
4465                          test_bit(R5_Expanded, &dev->flags))
4466                         /* If we've reshaped into here, we assume it is Insync.
4467                          * We will shortly update recovery_offset to make
4468                          * it official.
4469                          */
4470                         set_bit(R5_Insync, &dev->flags);
4471
4472                 if (test_bit(R5_WriteError, &dev->flags)) {
4473                         /* This flag does not apply to '.replacement'
4474                          * only to .rdev, so make sure to check that*/
4475                         struct md_rdev *rdev2 = rcu_dereference(
4476                                 conf->disks[i].rdev);
4477                         if (rdev2 == rdev)
4478                                 clear_bit(R5_Insync, &dev->flags);
4479                         if (rdev2 && !test_bit(Faulty, &rdev2->flags)) {
4480                                 s->handle_bad_blocks = 1;
4481                                 atomic_inc(&rdev2->nr_pending);
4482                         } else
4483                                 clear_bit(R5_WriteError, &dev->flags);
4484                 }
4485                 if (test_bit(R5_MadeGood, &dev->flags)) {
4486                         /* This flag does not apply to '.replacement'
4487                          * only to .rdev, so make sure to check that*/
4488                         struct md_rdev *rdev2 = rcu_dereference(
4489                                 conf->disks[i].rdev);
4490                         if (rdev2 && !test_bit(Faulty, &rdev2->flags)) {
4491                                 s->handle_bad_blocks = 1;
4492                                 atomic_inc(&rdev2->nr_pending);
4493                         } else
4494                                 clear_bit(R5_MadeGood, &dev->flags);
4495                 }
4496                 if (test_bit(R5_MadeGoodRepl, &dev->flags)) {
4497                         struct md_rdev *rdev2 = rcu_dereference(
4498                                 conf->disks[i].replacement);
4499                         if (rdev2 && !test_bit(Faulty, &rdev2->flags)) {
4500                                 s->handle_bad_blocks = 1;
4501                                 atomic_inc(&rdev2->nr_pending);
4502                         } else
4503                                 clear_bit(R5_MadeGoodRepl, &dev->flags);
4504                 }
4505                 if (!test_bit(R5_Insync, &dev->flags)) {
4506                         /* The ReadError flag will just be confusing now */
4507                         clear_bit(R5_ReadError, &dev->flags);
4508                         clear_bit(R5_ReWrite, &dev->flags);
4509                 }
4510                 if (test_bit(R5_ReadError, &dev->flags))
4511                         clear_bit(R5_Insync, &dev->flags);
4512                 if (!test_bit(R5_Insync, &dev->flags)) {
4513                         if (s->failed < 2)
4514                                 s->failed_num[s->failed] = i;
4515                         s->failed++;
4516                         if (rdev && !test_bit(Faulty, &rdev->flags))
4517                                 do_recovery = 1;
4518                 }
4519
4520                 if (test_bit(R5_InJournal, &dev->flags))
4521                         s->injournal++;
4522                 if (test_bit(R5_InJournal, &dev->flags) && dev->written)
4523                         s->just_cached++;
4524         }
4525         if (test_bit(STRIPE_SYNCING, &sh->state)) {
4526                 /* If there is a failed device being replaced,
4527                  *     we must be recovering.
4528                  * else if we are after recovery_cp, we must be syncing
4529                  * else if MD_RECOVERY_REQUESTED is set, we also are syncing.
4530                  * else we can only be replacing
4531                  * sync and recovery both need to read all devices, and so
4532                  * use the same flag.
4533                  */
4534                 if (do_recovery ||
4535                     sh->sector >= conf->mddev->recovery_cp ||
4536                     test_bit(MD_RECOVERY_REQUESTED, &(conf->mddev->recovery)))
4537                         s->syncing = 1;
4538                 else
4539                         s->replacing = 1;
4540         }
4541         rcu_read_unlock();
4542 }
4543
4544 static int clear_batch_ready(struct stripe_head *sh)
4545 {
4546         /* Return '1' if this is a member of batch, or
4547          * '0' if it is a lone stripe or a head which can now be
4548          * handled.
4549          */
4550         struct stripe_head *tmp;
4551         if (!test_and_clear_bit(STRIPE_BATCH_READY, &sh->state))
4552                 return (sh->batch_head && sh->batch_head != sh);
4553         spin_lock(&sh->stripe_lock);
4554         if (!sh->batch_head) {
4555                 spin_unlock(&sh->stripe_lock);
4556                 return 0;
4557         }
4558
4559         /*
4560          * this stripe could be added to a batch list before we check
4561          * BATCH_READY, skips it
4562          */
4563         if (sh->batch_head != sh) {
4564                 spin_unlock(&sh->stripe_lock);
4565                 return 1;
4566         }
4567         spin_lock(&sh->batch_lock);
4568         list_for_each_entry(tmp, &sh->batch_list, batch_list)
4569                 clear_bit(STRIPE_BATCH_READY, &tmp->state);
4570         spin_unlock(&sh->batch_lock);
4571         spin_unlock(&sh->stripe_lock);
4572
4573         /*
4574          * BATCH_READY is cleared, no new stripes can be added.
4575          * batch_list can be accessed without lock
4576          */
4577         return 0;
4578 }
4579
4580 static void break_stripe_batch_list(struct stripe_head *head_sh,
4581                                     unsigned long handle_flags)
4582 {
4583         struct stripe_head *sh, *next;
4584         int i;
4585         int do_wakeup = 0;
4586
4587         list_for_each_entry_safe(sh, next, &head_sh->batch_list, batch_list) {
4588
4589                 list_del_init(&sh->batch_list);
4590
4591                 WARN_ONCE(sh->state & ((1 << STRIPE_ACTIVE) |
4592                                           (1 << STRIPE_SYNCING) |
4593                                           (1 << STRIPE_REPLACED) |
4594                                           (1 << STRIPE_DELAYED) |
4595                                           (1 << STRIPE_BIT_DELAY) |
4596                                           (1 << STRIPE_FULL_WRITE) |
4597                                           (1 << STRIPE_BIOFILL_RUN) |
4598                                           (1 << STRIPE_COMPUTE_RUN)  |
4599                                           (1 << STRIPE_OPS_REQ_PENDING) |
4600                                           (1 << STRIPE_DISCARD) |
4601                                           (1 << STRIPE_BATCH_READY) |
4602                                           (1 << STRIPE_BATCH_ERR) |
4603                                           (1 << STRIPE_BITMAP_PENDING)),
4604                         "stripe state: %lx\n", sh->state);
4605                 WARN_ONCE(head_sh->state & ((1 << STRIPE_DISCARD) |
4606                                               (1 << STRIPE_REPLACED)),
4607                         "head stripe state: %lx\n", head_sh->state);
4608
4609                 set_mask_bits(&sh->state, ~(STRIPE_EXPAND_SYNC_FLAGS |
4610                                             (1 << STRIPE_PREREAD_ACTIVE) |
4611                                             (1 << STRIPE_DEGRADED)),
4612                               head_sh->state & (1 << STRIPE_INSYNC));
4613
4614                 sh->check_state = head_sh->check_state;
4615                 sh->reconstruct_state = head_sh->reconstruct_state;
4616                 for (i = 0; i < sh->disks; i++) {
4617                         if (test_and_clear_bit(R5_Overlap, &sh->dev[i].flags))
4618                                 do_wakeup = 1;
4619                         sh->dev[i].flags = head_sh->dev[i].flags &
4620                                 (~((1 << R5_WriteError) | (1 << R5_Overlap)));
4621                 }
4622                 spin_lock_irq(&sh->stripe_lock);
4623                 sh->batch_head = NULL;
4624                 spin_unlock_irq(&sh->stripe_lock);
4625                 if (handle_flags == 0 ||
4626                     sh->state & handle_flags)
4627                         set_bit(STRIPE_HANDLE, &sh->state);
4628                 raid5_release_stripe(sh);
4629         }
4630         spin_lock_irq(&head_sh->stripe_lock);
4631         head_sh->batch_head = NULL;
4632         spin_unlock_irq(&head_sh->stripe_lock);
4633         for (i = 0; i < head_sh->disks; i++)
4634                 if (test_and_clear_bit(R5_Overlap, &head_sh->dev[i].flags))
4635                         do_wakeup = 1;
4636         if (head_sh->state & handle_flags)
4637                 set_bit(STRIPE_HANDLE, &head_sh->state);
4638
4639         if (do_wakeup)
4640                 wake_up(&head_sh->raid_conf->wait_for_overlap);
4641 }
4642
4643 static void handle_stripe(struct stripe_head *sh)
4644 {
4645         struct stripe_head_state s;
4646         struct r5conf *conf = sh->raid_conf;
4647         int i;
4648         int prexor;
4649         int disks = sh->disks;
4650         struct r5dev *pdev, *qdev;
4651
4652         clear_bit(STRIPE_HANDLE, &sh->state);
4653         if (test_and_set_bit_lock(STRIPE_ACTIVE, &sh->state)) {
4654                 /* already being handled, ensure it gets handled
4655                  * again when current action finishes */
4656                 set_bit(STRIPE_HANDLE, &sh->state);
4657                 return;
4658         }
4659
4660         if (clear_batch_ready(sh) ) {
4661                 clear_bit_unlock(STRIPE_ACTIVE, &sh->state);
4662                 return;
4663         }
4664
4665         if (test_and_clear_bit(STRIPE_BATCH_ERR, &sh->state))
4666                 break_stripe_batch_list(sh, 0);
4667
4668         if (test_bit(STRIPE_SYNC_REQUESTED, &sh->state) && !sh->batch_head) {
4669                 spin_lock(&sh->stripe_lock);
4670                 /*
4671                  * Cannot process 'sync' concurrently with 'discard'.
4672                  * Flush data in r5cache before 'sync'.
4673                  */
4674                 if (!test_bit(STRIPE_R5C_PARTIAL_STRIPE, &sh->state) &&
4675                     !test_bit(STRIPE_R5C_FULL_STRIPE, &sh->state) &&
4676                     !test_bit(STRIPE_DISCARD, &sh->state) &&
4677                     test_and_clear_bit(STRIPE_SYNC_REQUESTED, &sh->state)) {
4678                         set_bit(STRIPE_SYNCING, &sh->state);
4679                         clear_bit(STRIPE_INSYNC, &sh->state);
4680                         clear_bit(STRIPE_REPLACED, &sh->state);
4681                 }
4682                 spin_unlock(&sh->stripe_lock);
4683         }
4684         clear_bit(STRIPE_DELAYED, &sh->state);
4685
4686         pr_debug("handling stripe %llu, state=%#lx cnt=%d, "
4687                 "pd_idx=%d, qd_idx=%d\n, check:%d, reconstruct:%d\n",
4688                (unsigned long long)sh->sector, sh->state,
4689                atomic_read(&sh->count), sh->pd_idx, sh->qd_idx,
4690                sh->check_state, sh->reconstruct_state);
4691
4692         analyse_stripe(sh, &s);
4693
4694         if (test_bit(STRIPE_LOG_TRAPPED, &sh->state))
4695                 goto finish;
4696
4697         if (s.handle_bad_blocks ||
4698             test_bit(MD_SB_CHANGE_PENDING, &conf->mddev->sb_flags)) {
4699                 set_bit(STRIPE_HANDLE, &sh->state);
4700                 goto finish;
4701         }
4702
4703         if (unlikely(s.blocked_rdev)) {
4704                 if (s.syncing || s.expanding || s.expanded ||
4705                     s.replacing || s.to_write || s.written) {
4706                         set_bit(STRIPE_HANDLE, &sh->state);
4707                         goto finish;
4708                 }
4709                 /* There is nothing for the blocked_rdev to block */
4710                 rdev_dec_pending(s.blocked_rdev, conf->mddev);
4711                 s.blocked_rdev = NULL;
4712         }
4713
4714         if (s.to_fill && !test_bit(STRIPE_BIOFILL_RUN, &sh->state)) {
4715                 set_bit(STRIPE_OP_BIOFILL, &s.ops_request);
4716                 set_bit(STRIPE_BIOFILL_RUN, &sh->state);
4717         }
4718
4719         pr_debug("locked=%d uptodate=%d to_read=%d"
4720                " to_write=%d failed=%d failed_num=%d,%d\n",
4721                s.locked, s.uptodate, s.to_read, s.to_write, s.failed,
4722                s.failed_num[0], s.failed_num[1]);
4723         /*
4724          * check if the array has lost more than max_degraded devices and,
4725          * if so, some requests might need to be failed.
4726          *
4727          * When journal device failed (log_failed), we will only process
4728          * the stripe if there is data need write to raid disks
4729          */
4730         if (s.failed > conf->max_degraded ||
4731             (s.log_failed && s.injournal == 0)) {
4732                 sh->check_state = 0;
4733                 sh->reconstruct_state = 0;
4734                 break_stripe_batch_list(sh, 0);
4735                 if (s.to_read+s.to_write+s.written)
4736                         handle_failed_stripe(conf, sh, &s, disks);
4737                 if (s.syncing + s.replacing)
4738                         handle_failed_sync(conf, sh, &s);
4739         }
4740
4741         /* Now we check to see if any write operations have recently
4742          * completed
4743          */
4744         prexor = 0;
4745         if (sh->reconstruct_state == reconstruct_state_prexor_drain_result)
4746                 prexor = 1;
4747         if (sh->reconstruct_state == reconstruct_state_drain_result ||
4748             sh->reconstruct_state == reconstruct_state_prexor_drain_result) {
4749                 sh->reconstruct_state = reconstruct_state_idle;
4750
4751                 /* All the 'written' buffers and the parity block are ready to
4752                  * be written back to disk
4753                  */
4754                 BUG_ON(!test_bit(R5_UPTODATE, &sh->dev[sh->pd_idx].flags) &&
4755                        !test_bit(R5_Discard, &sh->dev[sh->pd_idx].flags));
4756                 BUG_ON(sh->qd_idx >= 0 &&
4757                        !test_bit(R5_UPTODATE, &sh->dev[sh->qd_idx].flags) &&
4758                        !test_bit(R5_Discard, &sh->dev[sh->qd_idx].flags));
4759                 for (i = disks; i--; ) {
4760                         struct r5dev *dev = &sh->dev[i];
4761                         if (test_bit(R5_LOCKED, &dev->flags) &&
4762                                 (i == sh->pd_idx || i == sh->qd_idx ||
4763                                  dev->written || test_bit(R5_InJournal,
4764                                                           &dev->flags))) {
4765                                 pr_debug("Writing block %d\n", i);
4766                                 set_bit(R5_Wantwrite, &dev->flags);
4767                                 if (prexor)
4768                                         continue;
4769                                 if (s.failed > 1)
4770                                         continue;
4771                                 if (!test_bit(R5_Insync, &dev->flags) ||
4772                                     ((i == sh->pd_idx || i == sh->qd_idx)  &&
4773                                      s.failed == 0))
4774                                         set_bit(STRIPE_INSYNC, &sh->state);
4775                         }
4776                 }
4777                 if (test_and_clear_bit(STRIPE_PREREAD_ACTIVE, &sh->state))
4778                         s.dec_preread_active = 1;
4779         }
4780
4781         /*
4782          * might be able to return some write requests if the parity blocks
4783          * are safe, or on a failed drive
4784          */
4785         pdev = &sh->dev[sh->pd_idx];
4786         s.p_failed = (s.failed >= 1 && s.failed_num[0] == sh->pd_idx)
4787                 || (s.failed >= 2 && s.failed_num[1] == sh->pd_idx);
4788         qdev = &sh->dev[sh->qd_idx];
4789         s.q_failed = (s.failed >= 1 && s.failed_num[0] == sh->qd_idx)
4790                 || (s.failed >= 2 && s.failed_num[1] == sh->qd_idx)
4791                 || conf->level < 6;
4792
4793         if (s.written &&
4794             (s.p_failed || ((test_bit(R5_Insync, &pdev->flags)
4795                              && !test_bit(R5_LOCKED, &pdev->flags)
4796                              && (test_bit(R5_UPTODATE, &pdev->flags) ||
4797                                  test_bit(R5_Discard, &pdev->flags))))) &&
4798             (s.q_failed || ((test_bit(R5_Insync, &qdev->flags)
4799                              && !test_bit(R5_LOCKED, &qdev->flags)
4800                              && (test_bit(R5_UPTODATE, &qdev->flags) ||
4801                                  test_bit(R5_Discard, &qdev->flags))))))
4802                 handle_stripe_clean_event(conf, sh, disks);
4803
4804         if (s.just_cached)
4805                 r5c_handle_cached_data_endio(conf, sh, disks);
4806         log_stripe_write_finished(sh);
4807
4808         /* Now we might consider reading some blocks, either to check/generate
4809          * parity, or to satisfy requests
4810          * or to load a block that is being partially written.
4811          */
4812         if (s.to_read || s.non_overwrite
4813             || (conf->level == 6 && s.to_write && s.failed)
4814             || (s.syncing && (s.uptodate + s.compute < disks))
4815             || s.replacing
4816             || s.expanding)
4817                 handle_stripe_fill(sh, &s, disks);
4818
4819         /*
4820          * When the stripe finishes full journal write cycle (write to journal
4821          * and raid disk), this is the clean up procedure so it is ready for
4822          * next operation.
4823          */
4824         r5c_finish_stripe_write_out(conf, sh, &s);
4825
4826         /*
4827          * Now to consider new write requests, cache write back and what else,
4828          * if anything should be read.  We do not handle new writes when:
4829          * 1/ A 'write' operation (copy+xor) is already in flight.
4830          * 2/ A 'check' operation is in flight, as it may clobber the parity
4831          *    block.
4832          * 3/ A r5c cache log write is in flight.
4833          */
4834
4835         if (!sh->reconstruct_state && !sh->check_state && !sh->log_io) {
4836                 if (!r5c_is_writeback(conf->log)) {
4837                         if (s.to_write)
4838                                 handle_stripe_dirtying(conf, sh, &s, disks);
4839                 } else { /* write back cache */
4840                         int ret = 0;
4841
4842                         /* First, try handle writes in caching phase */
4843                         if (s.to_write)
4844                                 ret = r5c_try_caching_write(conf, sh, &s,
4845                                                             disks);
4846                         /*
4847                          * If caching phase failed: ret == -EAGAIN
4848                          *    OR
4849                          * stripe under reclaim: !caching && injournal
4850                          *
4851                          * fall back to handle_stripe_dirtying()
4852                          */
4853                         if (ret == -EAGAIN ||
4854                             /* stripe under reclaim: !caching && injournal */
4855                             (!test_bit(STRIPE_R5C_CACHING, &sh->state) &&
4856                              s.injournal > 0)) {
4857                                 ret = handle_stripe_dirtying(conf, sh, &s,
4858                                                              disks);
4859                                 if (ret == -EAGAIN)
4860                                         goto finish;
4861                         }
4862                 }
4863         }
4864
4865         /* maybe we need to check and possibly fix the parity for this stripe
4866          * Any reads will already have been scheduled, so we just see if enough
4867          * data is available.  The parity check is held off while parity
4868          * dependent operations are in flight.
4869          */
4870         if (sh->check_state ||
4871             (s.syncing && s.locked == 0 &&
4872              !test_bit(STRIPE_COMPUTE_RUN, &sh->state) &&
4873              !test_bit(STRIPE_INSYNC, &sh->state))) {
4874                 if (conf->level == 6)
4875                         handle_parity_checks6(conf, sh, &s, disks);
4876                 else
4877                         handle_parity_checks5(conf, sh, &s, disks);
4878         }
4879
4880         if ((s.replacing || s.syncing) && s.locked == 0
4881             && !test_bit(STRIPE_COMPUTE_RUN, &sh->state)
4882             && !test_bit(STRIPE_REPLACED, &sh->state)) {
4883                 /* Write out to replacement devices where possible */
4884                 for (i = 0; i < conf->raid_disks; i++)
4885                         if (test_bit(R5_NeedReplace, &sh->dev[i].flags)) {
4886                                 WARN_ON(!test_bit(R5_UPTODATE, &sh->dev[i].flags));
4887                                 set_bit(R5_WantReplace, &sh->dev[i].flags);
4888                                 set_bit(R5_LOCKED, &sh->dev[i].flags);
4889                                 s.locked++;
4890                         }
4891                 if (s.replacing)
4892                         set_bit(STRIPE_INSYNC, &sh->state);
4893                 set_bit(STRIPE_REPLACED, &sh->state);
4894         }
4895         if ((s.syncing || s.replacing) && s.locked == 0 &&
4896             !test_bit(STRIPE_COMPUTE_RUN, &sh->state) &&
4897             test_bit(STRIPE_INSYNC, &sh->state)) {
4898                 md_done_sync(conf->mddev, STRIPE_SECTORS, 1);
4899                 clear_bit(STRIPE_SYNCING, &sh->state);
4900                 if (test_and_clear_bit(R5_Overlap, &sh->dev[sh->pd_idx].flags))
4901                         wake_up(&conf->wait_for_overlap);
4902         }
4903
4904         /* If the failed drives are just a ReadError, then we might need
4905          * to progress the repair/check process
4906          */
4907         if (s.failed <= conf->max_degraded && !conf->mddev->ro)
4908                 for (i = 0; i < s.failed; i++) {
4909                         struct r5dev *dev = &sh->dev[s.failed_num[i]];
4910                         if (test_bit(R5_ReadError, &dev->flags)
4911                             && !test_bit(R5_LOCKED, &dev->flags)
4912                             && test_bit(R5_UPTODATE, &dev->flags)
4913                                 ) {
4914                                 if (!test_bit(R5_ReWrite, &dev->flags)) {
4915                                         set_bit(R5_Wantwrite, &dev->flags);
4916                                         set_bit(R5_ReWrite, &dev->flags);
4917                                         set_bit(R5_LOCKED, &dev->flags);
4918                                         s.locked++;
4919                                 } else {
4920                                         /* let's read it back */
4921                                         set_bit(R5_Wantread, &dev->flags);
4922                                         set_bit(R5_LOCKED, &dev->flags);
4923                                         s.locked++;
4924                                 }
4925                         }
4926                 }
4927
4928         /* Finish reconstruct operations initiated by the expansion process */
4929         if (sh->reconstruct_state == reconstruct_state_result) {
4930                 struct stripe_head *sh_src
4931                         = raid5_get_active_stripe(conf, sh->sector, 1, 1, 1);
4932                 if (sh_src && test_bit(STRIPE_EXPAND_SOURCE, &sh_src->state)) {
4933                         /* sh cannot be written until sh_src has been read.
4934                          * so arrange for sh to be delayed a little
4935                          */
4936                         set_bit(STRIPE_DELAYED, &sh->state);
4937                         set_bit(STRIPE_HANDLE, &sh->state);
4938                         if (!test_and_set_bit(STRIPE_PREREAD_ACTIVE,
4939                                               &sh_src->state))
4940                                 atomic_inc(&conf->preread_active_stripes);
4941                         raid5_release_stripe(sh_src);
4942                         goto finish;
4943                 }
4944                 if (sh_src)
4945                         raid5_release_stripe(sh_src);
4946
4947                 sh->reconstruct_state = reconstruct_state_idle;
4948                 clear_bit(STRIPE_EXPANDING, &sh->state);
4949                 for (i = conf->raid_disks; i--; ) {
4950                         set_bit(R5_Wantwrite, &sh->dev[i].flags);
4951                         set_bit(R5_LOCKED, &sh->dev[i].flags);
4952                         s.locked++;
4953                 }
4954         }
4955
4956         if (s.expanded && test_bit(STRIPE_EXPANDING, &sh->state) &&
4957             !sh->reconstruct_state) {
4958                 /* Need to write out all blocks after computing parity */
4959                 sh->disks = conf->raid_disks;
4960                 stripe_set_idx(sh->sector, conf, 0, sh);
4961                 schedule_reconstruction(sh, &s, 1, 1);
4962         } else if (s.expanded && !sh->reconstruct_state && s.locked == 0) {
4963                 clear_bit(STRIPE_EXPAND_READY, &sh->state);
4964                 atomic_dec(&conf->reshape_stripes);
4965                 wake_up(&conf->wait_for_overlap);
4966                 md_done_sync(conf->mddev, STRIPE_SECTORS, 1);
4967         }
4968
4969         if (s.expanding && s.locked == 0 &&
4970             !test_bit(STRIPE_COMPUTE_RUN, &sh->state))
4971                 handle_stripe_expansion(conf, sh);
4972
4973 finish:
4974         /* wait for this device to become unblocked */
4975         if (unlikely(s.blocked_rdev)) {
4976                 if (conf->mddev->external)
4977                         md_wait_for_blocked_rdev(s.blocked_rdev,
4978                                                  conf->mddev);
4979                 else
4980                         /* Internal metadata will immediately
4981                          * be written by raid5d, so we don't
4982                          * need to wait here.
4983                          */
4984                         rdev_dec_pending(s.blocked_rdev,
4985                                          conf->mddev);
4986         }
4987
4988         if (s.handle_bad_blocks)
4989                 for (i = disks; i--; ) {
4990                         struct md_rdev *rdev;
4991                         struct r5dev *dev = &sh->dev[i];
4992                         if (test_and_clear_bit(R5_WriteError, &dev->flags)) {
4993                                 /* We own a safe reference to the rdev */
4994                                 rdev = conf->disks[i].rdev;
4995                                 if (!rdev_set_badblocks(rdev, sh->sector,
4996                                                         STRIPE_SECTORS, 0))
4997                                         md_error(conf->mddev, rdev);
4998                                 rdev_dec_pending(rdev, conf->mddev);
4999                         }
5000                         if (test_and_clear_bit(R5_MadeGood, &dev->flags)) {
5001                                 rdev = conf->disks[i].rdev;
5002                                 rdev_clear_badblocks(rdev, sh->sector,
5003                                                      STRIPE_SECTORS, 0);
5004                                 rdev_dec_pending(rdev, conf->mddev);
5005                         }
5006                         if (test_and_clear_bit(R5_MadeGoodRepl, &dev->flags)) {
5007                                 rdev = conf->disks[i].replacement;
5008                                 if (!rdev)
5009                                         /* rdev have been moved down */
5010                                         rdev = conf->disks[i].rdev;
5011                                 rdev_clear_badblocks(rdev, sh->sector,
5012                                                      STRIPE_SECTORS, 0);
5013                                 rdev_dec_pending(rdev, conf->mddev);
5014                         }
5015                 }
5016
5017         if (s.ops_request)
5018                 raid_run_ops(sh, s.ops_request);
5019
5020         ops_run_io(sh, &s);
5021
5022         if (s.dec_preread_active) {
5023                 /* We delay this until after ops_run_io so that if make_request
5024                  * is waiting on a flush, it won't continue until the writes
5025                  * have actually been submitted.
5026                  */
5027                 atomic_dec(&conf->preread_active_stripes);
5028                 if (atomic_read(&conf->preread_active_stripes) <
5029                     IO_THRESHOLD)
5030                         md_wakeup_thread(conf->mddev->thread);
5031         }
5032
5033         clear_bit_unlock(STRIPE_ACTIVE, &sh->state);
5034 }
5035
5036 static void raid5_activate_delayed(struct r5conf *conf)
5037 {
5038         if (atomic_read(&conf->preread_active_stripes) < IO_THRESHOLD) {
5039                 while (!list_empty(&conf->delayed_list)) {
5040                         struct list_head *l = conf->delayed_list.next;
5041                         struct stripe_head *sh;
5042                         sh = list_entry(l, struct stripe_head, lru);
5043                         list_del_init(l);
5044                         clear_bit(STRIPE_DELAYED, &sh->state);
5045                         if (!test_and_set_bit(STRIPE_PREREAD_ACTIVE, &sh->state))
5046                                 atomic_inc(&conf->preread_active_stripes);
5047                         list_add_tail(&sh->lru, &conf->hold_list);
5048                         raid5_wakeup_stripe_thread(sh);
5049                 }
5050         }
5051 }
5052
5053 static void activate_bit_delay(struct r5conf *conf,
5054         struct list_head *temp_inactive_list)
5055 {
5056         /* device_lock is held */
5057         struct list_head head;
5058         list_add(&head, &conf->bitmap_list);
5059         list_del_init(&conf->bitmap_list);
5060         while (!list_empty(&head)) {
5061                 struct stripe_head *sh = list_entry(head.next, struct stripe_head, lru);
5062                 int hash;
5063                 list_del_init(&sh->lru);
5064                 atomic_inc(&sh->count);
5065                 hash = sh->hash_lock_index;
5066                 __release_stripe(conf, sh, &temp_inactive_list[hash]);
5067         }
5068 }
5069
5070 static int raid5_congested(struct mddev *mddev, int bits)
5071 {
5072         struct r5conf *conf = mddev->private;
5073
5074         /* No difference between reads and writes.  Just check
5075          * how busy the stripe_cache is
5076          */
5077
5078         if (test_bit(R5_INACTIVE_BLOCKED, &conf->cache_state))
5079                 return 1;
5080
5081         /* Also checks whether there is pressure on r5cache log space */
5082         if (test_bit(R5C_LOG_TIGHT, &conf->cache_state))
5083                 return 1;
5084         if (conf->quiesce)
5085                 return 1;
5086         if (atomic_read(&conf->empty_inactive_list_nr))
5087                 return 1;
5088
5089         return 0;
5090 }
5091
5092 static int in_chunk_boundary(struct mddev *mddev, struct bio *bio)
5093 {
5094         struct r5conf *conf = mddev->private;
5095         sector_t sector = bio->bi_iter.bi_sector;
5096         unsigned int chunk_sectors;
5097         unsigned int bio_sectors = bio_sectors(bio);
5098
5099         WARN_ON_ONCE(bio->bi_partno);
5100
5101         chunk_sectors = min(conf->chunk_sectors, conf->prev_chunk_sectors);
5102         return  chunk_sectors >=
5103                 ((sector & (chunk_sectors - 1)) + bio_sectors);
5104 }
5105
5106 /*
5107  *  add bio to the retry LIFO  ( in O(1) ... we are in interrupt )
5108  *  later sampled by raid5d.
5109  */
5110 static void add_bio_to_retry(struct bio *bi,struct r5conf *conf)
5111 {
5112         unsigned long flags;
5113
5114         spin_lock_irqsave(&conf->device_lock, flags);
5115
5116         bi->bi_next = conf->retry_read_aligned_list;
5117         conf->retry_read_aligned_list = bi;
5118
5119         spin_unlock_irqrestore(&conf->device_lock, flags);
5120         md_wakeup_thread(conf->mddev->thread);
5121 }
5122
5123 static struct bio *remove_bio_from_retry(struct r5conf *conf,
5124                                          unsigned int *offset)
5125 {
5126         struct bio *bi;
5127
5128         bi = conf->retry_read_aligned;
5129         if (bi) {
5130                 *offset = conf->retry_read_offset;
5131                 conf->retry_read_aligned = NULL;
5132                 return bi;
5133         }
5134         bi = conf->retry_read_aligned_list;
5135         if(bi) {
5136                 conf->retry_read_aligned_list = bi->bi_next;
5137                 bi->bi_next = NULL;
5138                 *offset = 0;
5139         }
5140
5141         return bi;
5142 }
5143
5144 /*
5145  *  The "raid5_align_endio" should check if the read succeeded and if it
5146  *  did, call bio_endio on the original bio (having bio_put the new bio
5147  *  first).
5148  *  If the read failed..
5149  */
5150 static void raid5_align_endio(struct bio *bi)
5151 {
5152         struct bio* raid_bi  = bi->bi_private;
5153         struct mddev *mddev;
5154         struct r5conf *conf;
5155         struct md_rdev *rdev;
5156         blk_status_t error = bi->bi_status;
5157
5158         bio_put(bi);
5159
5160         rdev = (void*)raid_bi->bi_next;
5161         raid_bi->bi_next = NULL;
5162         mddev = rdev->mddev;
5163         conf = mddev->private;
5164
5165         rdev_dec_pending(rdev, conf->mddev);
5166
5167         if (!error) {
5168                 bio_endio(raid_bi);
5169                 if (atomic_dec_and_test(&conf->active_aligned_reads))
5170                         wake_up(&conf->wait_for_quiescent);
5171                 return;
5172         }
5173
5174         pr_debug("raid5_align_endio : io error...handing IO for a retry\n");
5175
5176         add_bio_to_retry(raid_bi, conf);
5177 }
5178
5179 static int raid5_read_one_chunk(struct mddev *mddev, struct bio *raid_bio)
5180 {
5181         struct r5conf *conf = mddev->private;
5182         int dd_idx;
5183         struct bio* align_bi;
5184         struct md_rdev *rdev;
5185         sector_t end_sector;
5186
5187         if (!in_chunk_boundary(mddev, raid_bio)) {
5188                 pr_debug("%s: non aligned\n", __func__);
5189                 return 0;
5190         }
5191         /*
5192          * use bio_clone_fast to make a copy of the bio
5193          */
5194         align_bi = bio_clone_fast(raid_bio, GFP_NOIO, mddev->bio_set);
5195         if (!align_bi)
5196                 return 0;
5197         /*
5198          *   set bi_end_io to a new function, and set bi_private to the
5199          *     original bio.
5200          */
5201         align_bi->bi_end_io  = raid5_align_endio;
5202         align_bi->bi_private = raid_bio;
5203         /*
5204          *      compute position
5205          */
5206         align_bi->bi_iter.bi_sector =
5207                 raid5_compute_sector(conf, raid_bio->bi_iter.bi_sector,
5208                                      0, &dd_idx, NULL);
5209
5210         end_sector = bio_end_sector(align_bi);
5211         rcu_read_lock();
5212         rdev = rcu_dereference(conf->disks[dd_idx].replacement);
5213         if (!rdev || test_bit(Faulty, &rdev->flags) ||
5214             rdev->recovery_offset < end_sector) {
5215                 rdev = rcu_dereference(conf->disks[dd_idx].rdev);
5216                 if (rdev &&
5217                     (test_bit(Faulty, &rdev->flags) ||
5218                     !(test_bit(In_sync, &rdev->flags) ||
5219                       rdev->recovery_offset >= end_sector)))
5220                         rdev = NULL;
5221         }
5222
5223         if (r5c_big_stripe_cached(conf, align_bi->bi_iter.bi_sector)) {
5224                 rcu_read_unlock();
5225                 bio_put(align_bi);
5226                 return 0;
5227         }
5228
5229         if (rdev) {
5230                 sector_t first_bad;
5231                 int bad_sectors;
5232
5233                 atomic_inc(&rdev->nr_pending);
5234                 rcu_read_unlock();
5235                 raid_bio->bi_next = (void*)rdev;
5236                 bio_set_dev(align_bi, rdev->bdev);
5237                 bio_clear_flag(align_bi, BIO_SEG_VALID);
5238
5239                 if (is_badblock(rdev, align_bi->bi_iter.bi_sector,
5240                                 bio_sectors(align_bi),
5241                                 &first_bad, &bad_sectors)) {
5242                         bio_put(align_bi);
5243                         rdev_dec_pending(rdev, mddev);
5244                         return 0;
5245                 }
5246
5247                 /* No reshape active, so we can trust rdev->data_offset */
5248                 align_bi->bi_iter.bi_sector += rdev->data_offset;
5249
5250                 spin_lock_irq(&conf->device_lock);
5251                 wait_event_lock_irq(conf->wait_for_quiescent,
5252                                     conf->quiesce == 0,
5253                                     conf->device_lock);
5254                 atomic_inc(&conf->active_aligned_reads);
5255                 spin_unlock_irq(&conf->device_lock);
5256
5257                 if (mddev->gendisk)
5258                         trace_block_bio_remap(align_bi->bi_disk->queue,
5259                                               align_bi, disk_devt(mddev->gendisk),
5260                                               raid_bio->bi_iter.bi_sector);
5261                 generic_make_request(align_bi);
5262                 return 1;
5263         } else {
5264                 rcu_read_unlock();
5265                 bio_put(align_bi);
5266                 return 0;
5267         }
5268 }
5269
5270 static struct bio *chunk_aligned_read(struct mddev *mddev, struct bio *raid_bio)
5271 {
5272         struct bio *split;
5273         sector_t sector = raid_bio->bi_iter.bi_sector;
5274         unsigned chunk_sects = mddev->chunk_sectors;
5275         unsigned sectors = chunk_sects - (sector & (chunk_sects-1));
5276
5277         if (sectors < bio_sectors(raid_bio)) {
5278                 struct r5conf *conf = mddev->private;
5279                 split = bio_split(raid_bio, sectors, GFP_NOIO, conf->bio_split);
5280                 bio_chain(split, raid_bio);
5281                 generic_make_request(raid_bio);
5282                 raid_bio = split;
5283         }
5284
5285         if (!raid5_read_one_chunk(mddev, raid_bio))
5286                 return raid_bio;
5287
5288         return NULL;
5289 }
5290
5291 /* __get_priority_stripe - get the next stripe to process
5292  *
5293  * Full stripe writes are allowed to pass preread active stripes up until
5294  * the bypass_threshold is exceeded.  In general the bypass_count
5295  * increments when the handle_list is handled before the hold_list; however, it
5296  * will not be incremented when STRIPE_IO_STARTED is sampled set signifying a
5297  * stripe with in flight i/o.  The bypass_count will be reset when the
5298  * head of the hold_list has changed, i.e. the head was promoted to the
5299  * handle_list.
5300  */
5301 static struct stripe_head *__get_priority_stripe(struct r5conf *conf, int group)
5302 {
5303         struct stripe_head *sh, *tmp;
5304         struct list_head *handle_list = NULL;
5305         struct r5worker_group *wg;
5306         bool second_try = !r5c_is_writeback(conf->log) &&
5307                 !r5l_log_disk_error(conf);
5308         bool try_loprio = test_bit(R5C_LOG_TIGHT, &conf->cache_state) ||
5309                 r5l_log_disk_error(conf);
5310
5311 again:
5312         wg = NULL;
5313         sh = NULL;
5314         if (conf->worker_cnt_per_group == 0) {
5315                 handle_list = try_loprio ? &conf->loprio_list :
5316                                         &conf->handle_list;
5317         } else if (group != ANY_GROUP) {
5318                 handle_list = try_loprio ? &conf->worker_groups[group].loprio_list :
5319                                 &conf->worker_groups[group].handle_list;
5320                 wg = &conf->worker_groups[group];
5321         } else {
5322                 int i;
5323                 for (i = 0; i < conf->group_cnt; i++) {
5324                         handle_list = try_loprio ? &conf->worker_groups[i].loprio_list :
5325                                 &conf->worker_groups[i].handle_list;
5326                         wg = &conf->worker_groups[i];
5327                         if (!list_empty(handle_list))
5328                                 break;
5329                 }
5330         }
5331
5332         pr_debug("%s: handle: %s hold: %s full_writes: %d bypass_count: %d\n",
5333                   __func__,
5334                   list_empty(handle_list) ? "empty" : "busy",
5335                   list_empty(&conf->hold_list) ? "empty" : "busy",
5336                   atomic_read(&conf->pending_full_writes), conf->bypass_count);
5337
5338         if (!list_empty(handle_list)) {
5339                 sh = list_entry(handle_list->next, typeof(*sh), lru);
5340
5341                 if (list_empty(&conf->hold_list))
5342                         conf->bypass_count = 0;
5343                 else if (!test_bit(STRIPE_IO_STARTED, &sh->state)) {
5344                         if (conf->hold_list.next == conf->last_hold)
5345                                 conf->bypass_count++;
5346                         else {
5347                                 conf->last_hold = conf->hold_list.next;
5348                                 conf->bypass_count -= conf->bypass_threshold;
5349                                 if (conf->bypass_count < 0)
5350                                         conf->bypass_count = 0;
5351                         }
5352                 }
5353         } else if (!list_empty(&conf->hold_list) &&
5354                    ((conf->bypass_threshold &&
5355                      conf->bypass_count > conf->bypass_threshold) ||
5356                     atomic_read(&conf->pending_full_writes) == 0)) {
5357
5358                 list_for_each_entry(tmp, &conf->hold_list,  lru) {
5359                         if (conf->worker_cnt_per_group == 0 ||
5360                             group == ANY_GROUP ||
5361                             !cpu_online(tmp->cpu) ||
5362                             cpu_to_group(tmp->cpu) == group) {
5363                                 sh = tmp;
5364                                 break;
5365                         }
5366                 }
5367
5368                 if (sh) {
5369                         conf->bypass_count -= conf->bypass_threshold;
5370                         if (conf->bypass_count < 0)
5371                                 conf->bypass_count = 0;
5372                 }
5373                 wg = NULL;
5374         }
5375
5376         if (!sh) {
5377                 if (second_try)
5378                         return NULL;
5379                 second_try = true;
5380                 try_loprio = !try_loprio;
5381                 goto again;
5382         }
5383
5384         if (wg) {
5385                 wg->stripes_cnt--;
5386                 sh->group = NULL;
5387         }
5388         list_del_init(&sh->lru);
5389         BUG_ON(atomic_inc_return(&sh->count) != 1);
5390         return sh;
5391 }
5392
5393 struct raid5_plug_cb {
5394         struct blk_plug_cb      cb;
5395         struct list_head        list;
5396         struct list_head        temp_inactive_list[NR_STRIPE_HASH_LOCKS];
5397 };
5398
5399 static void raid5_unplug(struct blk_plug_cb *blk_cb, bool from_schedule)
5400 {
5401         struct raid5_plug_cb *cb = container_of(
5402                 blk_cb, struct raid5_plug_cb, cb);
5403         struct stripe_head *sh;
5404         struct mddev *mddev = cb->cb.data;
5405         struct r5conf *conf = mddev->private;
5406         int cnt = 0;
5407         int hash;
5408
5409         if (cb->list.next && !list_empty(&cb->list)) {
5410                 spin_lock_irq(&conf->device_lock);
5411                 while (!list_empty(&cb->list)) {
5412                         sh = list_first_entry(&cb->list, struct stripe_head, lru);
5413                         list_del_init(&sh->lru);
5414                         /*
5415                          * avoid race release_stripe_plug() sees
5416                          * STRIPE_ON_UNPLUG_LIST clear but the stripe
5417                          * is still in our list
5418                          */
5419                         smp_mb__before_atomic();
5420                         clear_bit(STRIPE_ON_UNPLUG_LIST, &sh->state);
5421                         /*
5422                          * STRIPE_ON_RELEASE_LIST could be set here. In that
5423                          * case, the count is always > 1 here
5424                          */
5425                         hash = sh->hash_lock_index;
5426                         __release_stripe(conf, sh, &cb->temp_inactive_list[hash]);
5427                         cnt++;
5428                 }
5429                 spin_unlock_irq(&conf->device_lock);
5430         }
5431         release_inactive_stripe_list(conf, cb->temp_inactive_list,
5432                                      NR_STRIPE_HASH_LOCKS);
5433         if (mddev->queue)
5434                 trace_block_unplug(mddev->queue, cnt, !from_schedule);
5435         kfree(cb);
5436 }
5437
5438 static void release_stripe_plug(struct mddev *mddev,
5439                                 struct stripe_head *sh)
5440 {
5441         struct blk_plug_cb *blk_cb = blk_check_plugged(
5442                 raid5_unplug, mddev,
5443                 sizeof(struct raid5_plug_cb));
5444         struct raid5_plug_cb *cb;
5445
5446         if (!blk_cb) {
5447                 raid5_release_stripe(sh);
5448                 return;
5449         }
5450
5451         cb = container_of(blk_cb, struct raid5_plug_cb, cb);
5452
5453         if (cb->list.next == NULL) {
5454                 int i;
5455                 INIT_LIST_HEAD(&cb->list);
5456                 for (i = 0; i < NR_STRIPE_HASH_LOCKS; i++)
5457                         INIT_LIST_HEAD(cb->temp_inactive_list + i);
5458         }
5459
5460         if (!test_and_set_bit(STRIPE_ON_UNPLUG_LIST, &sh->state))
5461                 list_add_tail(&sh->lru, &cb->list);
5462         else
5463                 raid5_release_stripe(sh);
5464 }
5465
5466 static void make_discard_request(struct mddev *mddev, struct bio *bi)
5467 {
5468         struct r5conf *conf = mddev->private;
5469         sector_t logical_sector, last_sector;
5470         struct stripe_head *sh;
5471         int stripe_sectors;
5472
5473         if (mddev->reshape_position != MaxSector)
5474                 /* Skip discard while reshape is happening */
5475                 return;
5476
5477         logical_sector = bi->bi_iter.bi_sector & ~((sector_t)STRIPE_SECTORS-1);
5478         last_sector = bi->bi_iter.bi_sector + (bi->bi_iter.bi_size>>9);
5479
5480         bi->bi_next = NULL;
5481
5482         stripe_sectors = conf->chunk_sectors *
5483                 (conf->raid_disks - conf->max_degraded);
5484         logical_sector = DIV_ROUND_UP_SECTOR_T(logical_sector,
5485                                                stripe_sectors);
5486         sector_div(last_sector, stripe_sectors);
5487
5488         logical_sector *= conf->chunk_sectors;
5489         last_sector *= conf->chunk_sectors;
5490
5491         for (; logical_sector < last_sector;
5492              logical_sector += STRIPE_SECTORS) {
5493                 DEFINE_WAIT(w);
5494                 int d;
5495         again:
5496                 sh = raid5_get_active_stripe(conf, logical_sector, 0, 0, 0);
5497                 prepare_to_wait(&conf->wait_for_overlap, &w,
5498                                 TASK_UNINTERRUPTIBLE);
5499                 set_bit(R5_Overlap, &sh->dev[sh->pd_idx].flags);
5500                 if (test_bit(STRIPE_SYNCING, &sh->state)) {
5501                         raid5_release_stripe(sh);
5502                         schedule();
5503                         goto again;
5504                 }
5505                 clear_bit(R5_Overlap, &sh->dev[sh->pd_idx].flags);
5506                 spin_lock_irq(&sh->stripe_lock);
5507                 for (d = 0; d < conf->raid_disks; d++) {
5508                         if (d == sh->pd_idx || d == sh->qd_idx)
5509                                 continue;
5510                         if (sh->dev[d].towrite || sh->dev[d].toread) {
5511                                 set_bit(R5_Overlap, &sh->dev[d].flags);
5512                                 spin_unlock_irq(&sh->stripe_lock);
5513                                 raid5_release_stripe(sh);
5514                                 schedule();
5515                                 goto again;
5516                         }
5517                 }
5518                 set_bit(STRIPE_DISCARD, &sh->state);
5519                 finish_wait(&conf->wait_for_overlap, &w);
5520                 sh->overwrite_disks = 0;
5521                 for (d = 0; d < conf->raid_disks; d++) {
5522                         if (d == sh->pd_idx || d == sh->qd_idx)
5523                                 continue;
5524                         sh->dev[d].towrite = bi;
5525                         set_bit(R5_OVERWRITE, &sh->dev[d].flags);
5526                         bio_inc_remaining(bi);
5527                         md_write_inc(mddev, bi);
5528                         sh->overwrite_disks++;
5529                 }
5530                 spin_unlock_irq(&sh->stripe_lock);
5531                 if (conf->mddev->bitmap) {
5532                         for (d = 0;
5533                              d < conf->raid_disks - conf->max_degraded;
5534                              d++)
5535                                 bitmap_startwrite(mddev->bitmap,
5536                                                   sh->sector,
5537                                                   STRIPE_SECTORS,
5538                                                   0);
5539                         sh->bm_seq = conf->seq_flush + 1;
5540                         set_bit(STRIPE_BIT_DELAY, &sh->state);
5541                 }
5542
5543                 set_bit(STRIPE_HANDLE, &sh->state);
5544                 clear_bit(STRIPE_DELAYED, &sh->state);
5545                 if (!test_and_set_bit(STRIPE_PREREAD_ACTIVE, &sh->state))
5546                         atomic_inc(&conf->preread_active_stripes);
5547                 release_stripe_plug(mddev, sh);
5548         }
5549
5550         bio_endio(bi);
5551 }
5552
5553 static bool raid5_make_request(struct mddev *mddev, struct bio * bi)
5554 {
5555         struct r5conf *conf = mddev->private;
5556         int dd_idx;
5557         sector_t new_sector;
5558         sector_t logical_sector, last_sector;
5559         struct stripe_head *sh;
5560         const int rw = bio_data_dir(bi);
5561         DEFINE_WAIT(w);
5562         bool do_prepare;
5563         bool do_flush = false;
5564
5565         if (unlikely(bi->bi_opf & REQ_PREFLUSH)) {
5566                 int ret = r5l_handle_flush_request(conf->log, bi);
5567
5568                 if (ret == 0)
5569                         return true;
5570                 if (ret == -ENODEV) {
5571                         md_flush_request(mddev, bi);
5572                         return true;
5573                 }
5574                 /* ret == -EAGAIN, fallback */
5575                 /*
5576                  * if r5l_handle_flush_request() didn't clear REQ_PREFLUSH,
5577                  * we need to flush journal device
5578                  */
5579                 do_flush = bi->bi_opf & REQ_PREFLUSH;
5580         }
5581
5582         if (!md_write_start(mddev, bi))
5583                 return false;
5584         /*
5585          * If array is degraded, better not do chunk aligned read because
5586          * later we might have to read it again in order to reconstruct
5587          * data on failed drives.
5588          */
5589         if (rw == READ && mddev->degraded == 0 &&
5590             mddev->reshape_position == MaxSector) {
5591                 bi = chunk_aligned_read(mddev, bi);
5592                 if (!bi)
5593                         return true;
5594         }
5595
5596         if (unlikely(bio_op(bi) == REQ_OP_DISCARD)) {
5597                 make_discard_request(mddev, bi);
5598                 md_write_end(mddev);
5599                 return true;
5600         }
5601
5602         logical_sector = bi->bi_iter.bi_sector & ~((sector_t)STRIPE_SECTORS-1);
5603         last_sector = bio_end_sector(bi);
5604         bi->bi_next = NULL;
5605
5606         prepare_to_wait(&conf->wait_for_overlap, &w, TASK_UNINTERRUPTIBLE);
5607         for (;logical_sector < last_sector; logical_sector += STRIPE_SECTORS) {
5608                 int previous;
5609                 int seq;
5610
5611                 do_prepare = false;
5612         retry:
5613                 seq = read_seqcount_begin(&conf->gen_lock);
5614                 previous = 0;
5615                 if (do_prepare)
5616                         prepare_to_wait(&conf->wait_for_overlap, &w,
5617                                 TASK_UNINTERRUPTIBLE);
5618                 if (unlikely(conf->reshape_progress != MaxSector)) {
5619                         /* spinlock is needed as reshape_progress may be
5620                          * 64bit on a 32bit platform, and so it might be
5621                          * possible to see a half-updated value
5622                          * Of course reshape_progress could change after
5623                          * the lock is dropped, so once we get a reference
5624                          * to the stripe that we think it is, we will have
5625                          * to check again.
5626                          */
5627                         spin_lock_irq(&conf->device_lock);
5628                         if (mddev->reshape_backwards
5629                             ? logical_sector < conf->reshape_progress
5630                             : logical_sector >= conf->reshape_progress) {
5631                                 previous = 1;
5632                         } else {
5633                                 if (mddev->reshape_backwards
5634                                     ? logical_sector < conf->reshape_safe
5635                                     : logical_sector >= conf->reshape_safe) {
5636                                         spin_unlock_irq(&conf->device_lock);
5637                                         schedule();
5638                                         do_prepare = true;
5639                                         goto retry;
5640                                 }
5641                         }
5642                         spin_unlock_irq(&conf->device_lock);
5643                 }
5644
5645                 new_sector = raid5_compute_sector(conf, logical_sector,
5646                                                   previous,
5647                                                   &dd_idx, NULL);
5648                 pr_debug("raid456: raid5_make_request, sector %llu logical %llu\n",
5649                         (unsigned long long)new_sector,
5650                         (unsigned long long)logical_sector);
5651
5652                 sh = raid5_get_active_stripe(conf, new_sector, previous,
5653                                        (bi->bi_opf & REQ_RAHEAD), 0);
5654                 if (sh) {
5655                         if (unlikely(previous)) {
5656                                 /* expansion might have moved on while waiting for a
5657                                  * stripe, so we must do the range check again.
5658                                  * Expansion could still move past after this
5659                                  * test, but as we are holding a reference to
5660                                  * 'sh', we know that if that happens,
5661                                  *  STRIPE_EXPANDING will get set and the expansion
5662                                  * won't proceed until we finish with the stripe.
5663                                  */
5664                                 int must_retry = 0;
5665                                 spin_lock_irq(&conf->device_lock);
5666                                 if (mddev->reshape_backwards
5667                                     ? logical_sector >= conf->reshape_progress
5668                                     : logical_sector < conf->reshape_progress)
5669                                         /* mismatch, need to try again */
5670                                         must_retry = 1;
5671                                 spin_unlock_irq(&conf->device_lock);
5672                                 if (must_retry) {
5673                                         raid5_release_stripe(sh);
5674                                         schedule();
5675                                         do_prepare = true;
5676                                         goto retry;
5677                                 }
5678                         }
5679                         if (read_seqcount_retry(&conf->gen_lock, seq)) {
5680                                 /* Might have got the wrong stripe_head
5681                                  * by accident
5682                                  */
5683                                 raid5_release_stripe(sh);
5684                                 goto retry;
5685                         }
5686
5687                         if (rw == WRITE &&
5688                             logical_sector >= mddev->suspend_lo &&
5689                             logical_sector < mddev->suspend_hi) {
5690                                 raid5_release_stripe(sh);
5691                                 /* As the suspend_* range is controlled by
5692                                  * userspace, we want an interruptible
5693                                  * wait.
5694                                  */
5695                                 prepare_to_wait(&conf->wait_for_overlap,
5696                                                 &w, TASK_INTERRUPTIBLE);
5697                                 if (logical_sector >= mddev->suspend_lo &&
5698                                     logical_sector < mddev->suspend_hi) {
5699                                         sigset_t full, old;
5700                                         sigfillset(&full);
5701                                         sigprocmask(SIG_BLOCK, &full, &old);
5702                                         schedule();
5703                                         sigprocmask(SIG_SETMASK, &old, NULL);
5704                                         do_prepare = true;
5705                                 }
5706                                 goto retry;
5707                         }
5708
5709                         if (test_bit(STRIPE_EXPANDING, &sh->state) ||
5710                             !add_stripe_bio(sh, bi, dd_idx, rw, previous)) {
5711                                 /* Stripe is busy expanding or
5712                                  * add failed due to overlap.  Flush everything
5713                                  * and wait a while
5714                                  */
5715                                 md_wakeup_thread(mddev->thread);
5716                                 raid5_release_stripe(sh);
5717                                 schedule();
5718                                 do_prepare = true;
5719                                 goto retry;
5720                         }
5721                         if (do_flush) {
5722                                 set_bit(STRIPE_R5C_PREFLUSH, &sh->state);
5723                                 /* we only need flush for one stripe */
5724                                 do_flush = false;
5725                         }
5726
5727                         set_bit(STRIPE_HANDLE, &sh->state);
5728                         clear_bit(STRIPE_DELAYED, &sh->state);
5729                         if ((!sh->batch_head || sh == sh->batch_head) &&
5730                             (bi->bi_opf & REQ_SYNC) &&
5731                             !test_and_set_bit(STRIPE_PREREAD_ACTIVE, &sh->state))
5732                                 atomic_inc(&conf->preread_active_stripes);
5733                         release_stripe_plug(mddev, sh);
5734                 } else {
5735                         /* cannot get stripe for read-ahead, just give-up */
5736                         bi->bi_status = BLK_STS_IOERR;
5737                         break;
5738                 }
5739         }
5740         finish_wait(&conf->wait_for_overlap, &w);
5741
5742         if (rw == WRITE)
5743                 md_write_end(mddev);
5744         bio_endio(bi);
5745         return true;
5746 }
5747
5748 static sector_t raid5_size(struct mddev *mddev, sector_t sectors, int raid_disks);
5749
5750 static sector_t reshape_request(struct mddev *mddev, sector_t sector_nr, int *skipped)
5751 {
5752         /* reshaping is quite different to recovery/resync so it is
5753          * handled quite separately ... here.
5754          *
5755          * On each call to sync_request, we gather one chunk worth of
5756          * destination stripes and flag them as expanding.
5757          * Then we find all the source stripes and request reads.
5758          * As the reads complete, handle_stripe will copy the data
5759          * into the destination stripe and release that stripe.
5760          */
5761         struct r5conf *conf = mddev->private;
5762         struct stripe_head *sh;
5763         sector_t first_sector, last_sector;
5764         int raid_disks = conf->previous_raid_disks;
5765         int data_disks = raid_disks - conf->max_degraded;
5766         int new_data_disks = conf->raid_disks - conf->max_degraded;
5767         int i;
5768         int dd_idx;
5769         sector_t writepos, readpos, safepos;
5770         sector_t stripe_addr;
5771         int reshape_sectors;
5772         struct list_head stripes;
5773         sector_t retn;
5774
5775         if (sector_nr == 0) {
5776                 /* If restarting in the middle, skip the initial sectors */
5777                 if (mddev->reshape_backwards &&
5778                     conf->reshape_progress < raid5_size(mddev, 0, 0)) {
5779                         sector_nr = raid5_size(mddev, 0, 0)
5780                                 - conf->reshape_progress;
5781                 } else if (mddev->reshape_backwards &&
5782                            conf->reshape_progress == MaxSector) {
5783                         /* shouldn't happen, but just in case, finish up.*/
5784                         sector_nr = MaxSector;
5785                 } else if (!mddev->reshape_backwards &&
5786                            conf->reshape_progress > 0)
5787                         sector_nr = conf->reshape_progress;
5788                 sector_div(sector_nr, new_data_disks);
5789                 if (sector_nr) {
5790                         mddev->curr_resync_completed = sector_nr;
5791                         sysfs_notify(&mddev->kobj, NULL, "sync_completed");
5792                         *skipped = 1;
5793                         retn = sector_nr;
5794                         goto finish;
5795                 }
5796         }
5797
5798         /* We need to process a full chunk at a time.
5799          * If old and new chunk sizes differ, we need to process the
5800          * largest of these
5801          */
5802
5803         reshape_sectors = max(conf->chunk_sectors, conf->prev_chunk_sectors);
5804
5805         /* We update the metadata at least every 10 seconds, or when
5806          * the data about to be copied would over-write the source of
5807          * the data at the front of the range.  i.e. one new_stripe
5808          * along from reshape_progress new_maps to after where
5809          * reshape_safe old_maps to
5810          */
5811         writepos = conf->reshape_progress;
5812         sector_div(writepos, new_data_disks);
5813         readpos = conf->reshape_progress;
5814         sector_div(readpos, data_disks);
5815         safepos = conf->reshape_safe;
5816         sector_div(safepos, data_disks);
5817         if (mddev->reshape_backwards) {
5818                 BUG_ON(writepos < reshape_sectors);
5819                 writepos -= reshape_sectors;
5820                 readpos += reshape_sectors;
5821                 safepos += reshape_sectors;
5822         } else {
5823                 writepos += reshape_sectors;
5824                 /* readpos and safepos are worst-case calculations.
5825                  * A negative number is overly pessimistic, and causes
5826                  * obvious problems for unsigned storage.  So clip to 0.
5827                  */
5828                 readpos -= min_t(sector_t, reshape_sectors, readpos);
5829                 safepos -= min_t(sector_t, reshape_sectors, safepos);
5830         }
5831
5832         /* Having calculated the 'writepos' possibly use it
5833          * to set 'stripe_addr' which is where we will write to.
5834          */
5835         if (mddev->reshape_backwards) {
5836                 BUG_ON(conf->reshape_progress == 0);
5837                 stripe_addr = writepos;
5838                 BUG_ON((mddev->dev_sectors &
5839                         ~((sector_t)reshape_sectors - 1))
5840                        - reshape_sectors - stripe_addr
5841                        != sector_nr);
5842         } else {
5843                 BUG_ON(writepos != sector_nr + reshape_sectors);
5844                 stripe_addr = sector_nr;
5845         }
5846
5847         /* 'writepos' is the most advanced device address we might write.
5848          * 'readpos' is the least advanced device address we might read.
5849          * 'safepos' is the least address recorded in the metadata as having
5850          *     been reshaped.
5851          * If there is a min_offset_diff, these are adjusted either by
5852          * increasing the safepos/readpos if diff is negative, or
5853          * increasing writepos if diff is positive.
5854          * If 'readpos' is then behind 'writepos', there is no way that we can
5855          * ensure safety in the face of a crash - that must be done by userspace
5856          * making a backup of the data.  So in that case there is no particular
5857          * rush to update metadata.
5858          * Otherwise if 'safepos' is behind 'writepos', then we really need to
5859          * update the metadata to advance 'safepos' to match 'readpos' so that
5860          * we can be safe in the event of a crash.
5861          * So we insist on updating metadata if safepos is behind writepos and
5862          * readpos is beyond writepos.
5863          * In any case, update the metadata every 10 seconds.
5864          * Maybe that number should be configurable, but I'm not sure it is
5865          * worth it.... maybe it could be a multiple of safemode_delay???
5866          */
5867         if (conf->min_offset_diff < 0) {
5868                 safepos += -conf->min_offset_diff;
5869                 readpos += -conf->min_offset_diff;
5870         } else
5871                 writepos += conf->min_offset_diff;
5872
5873         if ((mddev->reshape_backwards
5874              ? (safepos > writepos && readpos < writepos)
5875              : (safepos < writepos && readpos > writepos)) ||
5876             time_after(jiffies, conf->reshape_checkpoint + 10*HZ)) {
5877                 /* Cannot proceed until we've updated the superblock... */
5878                 wait_event(conf->wait_for_overlap,
5879                            atomic_read(&conf->reshape_stripes)==0
5880                            || test_bit(MD_RECOVERY_INTR, &mddev->recovery));
5881                 if (atomic_read(&conf->reshape_stripes) != 0)
5882                         return 0;
5883                 mddev->reshape_position = conf->reshape_progress;
5884                 mddev->curr_resync_completed = sector_nr;
5885                 conf->reshape_checkpoint = jiffies;
5886                 set_bit(MD_SB_CHANGE_DEVS, &mddev->sb_flags);
5887                 md_wakeup_thread(mddev->thread);
5888                 wait_event(mddev->sb_wait, mddev->sb_flags == 0 ||
5889                            test_bit(MD_RECOVERY_INTR, &mddev->recovery));
5890                 if (test_bit(MD_RECOVERY_INTR, &mddev->recovery))
5891                         return 0;
5892                 spin_lock_irq(&conf->device_lock);
5893                 conf->reshape_safe = mddev->reshape_position;
5894                 spin_unlock_irq(&conf->device_lock);
5895                 wake_up(&conf->wait_for_overlap);
5896                 sysfs_notify(&mddev->kobj, NULL, "sync_completed");
5897         }
5898
5899         INIT_LIST_HEAD(&stripes);
5900         for (i = 0; i < reshape_sectors; i += STRIPE_SECTORS) {
5901                 int j;
5902                 int skipped_disk = 0;
5903                 sh = raid5_get_active_stripe(conf, stripe_addr+i, 0, 0, 1);
5904                 set_bit(STRIPE_EXPANDING, &sh->state);
5905                 atomic_inc(&conf->reshape_stripes);
5906                 /* If any of this stripe is beyond the end of the old
5907                  * array, then we need to zero those blocks
5908                  */
5909                 for (j=sh->disks; j--;) {
5910                         sector_t s;
5911                         if (j == sh->pd_idx)
5912                                 continue;
5913                         if (conf->level == 6 &&
5914                             j == sh->qd_idx)
5915                                 continue;
5916                         s = raid5_compute_blocknr(sh, j, 0);
5917                         if (s < raid5_size(mddev, 0, 0)) {
5918                                 skipped_disk = 1;
5919                                 continue;
5920                         }
5921                         memset(page_address(sh->dev[j].page), 0, STRIPE_SIZE);
5922                         set_bit(R5_Expanded, &sh->dev[j].flags);
5923                         set_bit(R5_UPTODATE, &sh->dev[j].flags);
5924                 }
5925                 if (!skipped_disk) {
5926                         set_bit(STRIPE_EXPAND_READY, &sh->state);
5927                         set_bit(STRIPE_HANDLE, &sh->state);
5928                 }
5929                 list_add(&sh->lru, &stripes);
5930         }
5931         spin_lock_irq(&conf->device_lock);
5932         if (mddev->reshape_backwards)
5933                 conf->reshape_progress -= reshape_sectors * new_data_disks;
5934         else
5935                 conf->reshape_progress += reshape_sectors * new_data_disks;
5936         spin_unlock_irq(&conf->device_lock);
5937         /* Ok, those stripe are ready. We can start scheduling
5938          * reads on the source stripes.
5939          * The source stripes are determined by mapping the first and last
5940          * block on the destination stripes.
5941          */
5942         first_sector =
5943                 raid5_compute_sector(conf, stripe_addr*(new_data_disks),
5944                                      1, &dd_idx, NULL);
5945         last_sector =
5946                 raid5_compute_sector(conf, ((stripe_addr+reshape_sectors)
5947                                             * new_data_disks - 1),
5948                                      1, &dd_idx, NULL);
5949         if (last_sector >= mddev->dev_sectors)
5950                 last_sector = mddev->dev_sectors - 1;
5951         while (first_sector <= last_sector) {
5952                 sh = raid5_get_active_stripe(conf, first_sector, 1, 0, 1);
5953                 set_bit(STRIPE_EXPAND_SOURCE, &sh->state);
5954                 set_bit(STRIPE_HANDLE, &sh->state);
5955                 raid5_release_stripe(sh);
5956                 first_sector += STRIPE_SECTORS;
5957         }
5958         /* Now that the sources are clearly marked, we can release
5959          * the destination stripes
5960          */
5961         while (!list_empty(&stripes)) {
5962                 sh = list_entry(stripes.next, struct stripe_head, lru);
5963                 list_del_init(&sh->lru);
5964                 raid5_release_stripe(sh);
5965         }
5966         /* If this takes us to the resync_max point where we have to pause,
5967          * then we need to write out the superblock.
5968          */
5969         sector_nr += reshape_sectors;
5970         retn = reshape_sectors;
5971 finish:
5972         if (mddev->curr_resync_completed > mddev->resync_max ||
5973             (sector_nr - mddev->curr_resync_completed) * 2
5974             >= mddev->resync_max - mddev->curr_resync_completed) {
5975                 /* Cannot proceed until we've updated the superblock... */
5976                 wait_event(conf->wait_for_overlap,
5977                            atomic_read(&conf->reshape_stripes) == 0
5978                            || test_bit(MD_RECOVERY_INTR, &mddev->recovery));
5979                 if (atomic_read(&conf->reshape_stripes) != 0)
5980                         goto ret;
5981                 mddev->reshape_position = conf->reshape_progress;
5982                 mddev->curr_resync_completed = sector_nr;
5983                 conf->reshape_checkpoint = jiffies;
5984                 set_bit(MD_SB_CHANGE_DEVS, &mddev->sb_flags);
5985                 md_wakeup_thread(mddev->thread);
5986                 wait_event(mddev->sb_wait,
5987                            !test_bit(MD_SB_CHANGE_DEVS, &mddev->sb_flags)
5988                            || test_bit(MD_RECOVERY_INTR, &mddev->recovery));
5989                 if (test_bit(MD_RECOVERY_INTR, &mddev->recovery))
5990                         goto ret;
5991                 spin_lock_irq(&conf->device_lock);
5992                 conf->reshape_safe = mddev->reshape_position;
5993                 spin_unlock_irq(&conf->device_lock);
5994                 wake_up(&conf->wait_for_overlap);
5995                 sysfs_notify(&mddev->kobj, NULL, "sync_completed");
5996         }
5997 ret:
5998         return retn;
5999 }
6000
6001 static inline sector_t raid5_sync_request(struct mddev *mddev, sector_t sector_nr,
6002                                           int *skipped)
6003 {
6004         struct r5conf *conf = mddev->private;
6005         struct stripe_head *sh;
6006         sector_t max_sector = mddev->dev_sectors;
6007         sector_t sync_blocks;
6008         int still_degraded = 0;
6009         int i;
6010
6011         if (sector_nr >= max_sector) {
6012                 /* just being told to finish up .. nothing much to do */
6013
6014                 if (test_bit(MD_RECOVERY_RESHAPE, &mddev->recovery)) {
6015                         end_reshape(conf);
6016                         return 0;
6017                 }
6018
6019                 if (mddev->curr_resync < max_sector) /* aborted */
6020                         bitmap_end_sync(mddev->bitmap, mddev->curr_resync,
6021                                         &sync_blocks, 1);
6022                 else /* completed sync */
6023                         conf->fullsync = 0;
6024                 bitmap_close_sync(mddev->bitmap);
6025
6026                 return 0;
6027         }
6028
6029         /* Allow raid5_quiesce to complete */
6030         wait_event(conf->wait_for_overlap, conf->quiesce != 2);
6031
6032         if (test_bit(MD_RECOVERY_RESHAPE, &mddev->recovery))
6033                 return reshape_request(mddev, sector_nr, skipped);
6034
6035         /* No need to check resync_max as we never do more than one
6036          * stripe, and as resync_max will always be on a chunk boundary,
6037          * if the check in md_do_sync didn't fire, there is no chance
6038          * of overstepping resync_max here
6039          */
6040
6041         /* if there is too many failed drives and we are trying
6042          * to resync, then assert that we are finished, because there is
6043          * nothing we can do.
6044          */
6045         if (mddev->degraded >= conf->max_degraded &&
6046             test_bit(MD_RECOVERY_SYNC, &mddev->recovery)) {
6047                 sector_t rv = mddev->dev_sectors - sector_nr;
6048                 *skipped = 1;
6049                 return rv;
6050         }
6051         if (!test_bit(MD_RECOVERY_REQUESTED, &mddev->recovery) &&
6052             !conf->fullsync &&
6053             !bitmap_start_sync(mddev->bitmap, sector_nr, &sync_blocks, 1) &&
6054             sync_blocks >= STRIPE_SECTORS) {
6055                 /* we can skip this block, and probably more */
6056                 sync_blocks /= STRIPE_SECTORS;
6057                 *skipped = 1;
6058                 return sync_blocks * STRIPE_SECTORS; /* keep things rounded to whole stripes */
6059         }
6060
6061         bitmap_cond_end_sync(mddev->bitmap, sector_nr, false);
6062
6063         sh = raid5_get_active_stripe(conf, sector_nr, 0, 1, 0);
6064         if (sh == NULL) {
6065                 sh = raid5_get_active_stripe(conf, sector_nr, 0, 0, 0);
6066                 /* make sure we don't swamp the stripe cache if someone else
6067                  * is trying to get access
6068                  */
6069                 schedule_timeout_uninterruptible(1);
6070         }
6071         /* Need to check if array will still be degraded after recovery/resync
6072          * Note in case of > 1 drive failures it's possible we're rebuilding
6073          * one drive while leaving another faulty drive in array.
6074          */
6075         rcu_read_lock();
6076         for (i = 0; i < conf->raid_disks; i++) {
6077                 struct md_rdev *rdev = ACCESS_ONCE(conf->disks[i].rdev);
6078
6079                 if (rdev == NULL || test_bit(Faulty, &rdev->flags))
6080                         still_degraded = 1;
6081         }
6082         rcu_read_unlock();
6083
6084         bitmap_start_sync(mddev->bitmap, sector_nr, &sync_blocks, still_degraded);
6085
6086         set_bit(STRIPE_SYNC_REQUESTED, &sh->state);
6087         set_bit(STRIPE_HANDLE, &sh->state);
6088
6089         raid5_release_stripe(sh);
6090
6091         return STRIPE_SECTORS;
6092 }
6093
6094 static int  retry_aligned_read(struct r5conf *conf, struct bio *raid_bio,
6095                                unsigned int offset)
6096 {
6097         /* We may not be able to submit a whole bio at once as there
6098          * may not be enough stripe_heads available.
6099          * We cannot pre-allocate enough stripe_heads as we may need
6100          * more than exist in the cache (if we allow ever large chunks).
6101          * So we do one stripe head at a time and record in
6102          * ->bi_hw_segments how many have been done.
6103          *
6104          * We *know* that this entire raid_bio is in one chunk, so
6105          * it will be only one 'dd_idx' and only need one call to raid5_compute_sector.
6106          */
6107         struct stripe_head *sh;
6108         int dd_idx;
6109         sector_t sector, logical_sector, last_sector;
6110         int scnt = 0;
6111         int handled = 0;
6112
6113         logical_sector = raid_bio->bi_iter.bi_sector &
6114                 ~((sector_t)STRIPE_SECTORS-1);
6115         sector = raid5_compute_sector(conf, logical_sector,
6116                                       0, &dd_idx, NULL);
6117         last_sector = bio_end_sector(raid_bio);
6118
6119         for (; logical_sector < last_sector;
6120              logical_sector += STRIPE_SECTORS,
6121                      sector += STRIPE_SECTORS,
6122                      scnt++) {
6123
6124                 if (scnt < offset)
6125                         /* already done this stripe */
6126                         continue;
6127
6128                 sh = raid5_get_active_stripe(conf, sector, 0, 1, 1);
6129
6130                 if (!sh) {
6131                         /* failed to get a stripe - must wait */
6132                         conf->retry_read_aligned = raid_bio;
6133                         conf->retry_read_offset = scnt;
6134                         return handled;
6135                 }
6136
6137                 if (!add_stripe_bio(sh, raid_bio, dd_idx, 0, 0)) {
6138                         raid5_release_stripe(sh);
6139                         conf->retry_read_aligned = raid_bio;
6140                         conf->retry_read_offset = scnt;
6141                         return handled;
6142                 }
6143
6144                 set_bit(R5_ReadNoMerge, &sh->dev[dd_idx].flags);
6145                 handle_stripe(sh);
6146                 raid5_release_stripe(sh);
6147                 handled++;
6148         }
6149
6150         bio_endio(raid_bio);
6151
6152         if (atomic_dec_and_test(&conf->active_aligned_reads))
6153                 wake_up(&conf->wait_for_quiescent);
6154         return handled;
6155 }
6156
6157 static int handle_active_stripes(struct r5conf *conf, int group,
6158                                  struct r5worker *worker,
6159                                  struct list_head *temp_inactive_list)
6160 {
6161         struct stripe_head *batch[MAX_STRIPE_BATCH], *sh;
6162         int i, batch_size = 0, hash;
6163         bool release_inactive = false;
6164
6165         while (batch_size < MAX_STRIPE_BATCH &&
6166                         (sh = __get_priority_stripe(conf, group)) != NULL)
6167                 batch[batch_size++] = sh;
6168
6169         if (batch_size == 0) {
6170                 for (i = 0; i < NR_STRIPE_HASH_LOCKS; i++)
6171                         if (!list_empty(temp_inactive_list + i))
6172                                 break;
6173                 if (i == NR_STRIPE_HASH_LOCKS) {
6174                         spin_unlock_irq(&conf->device_lock);
6175                         r5l_flush_stripe_to_raid(conf->log);
6176                         spin_lock_irq(&conf->device_lock);
6177                         return batch_size;
6178                 }
6179                 release_inactive = true;
6180         }
6181         spin_unlock_irq(&conf->device_lock);
6182
6183         release_inactive_stripe_list(conf, temp_inactive_list,
6184                                      NR_STRIPE_HASH_LOCKS);
6185
6186         r5l_flush_stripe_to_raid(conf->log);
6187         if (release_inactive) {
6188                 spin_lock_irq(&conf->device_lock);
6189                 return 0;
6190         }
6191
6192         for (i = 0; i < batch_size; i++)
6193                 handle_stripe(batch[i]);
6194         log_write_stripe_run(conf);
6195
6196         cond_resched();
6197
6198         spin_lock_irq(&conf->device_lock);
6199         for (i = 0; i < batch_size; i++) {
6200                 hash = batch[i]->hash_lock_index;
6201                 __release_stripe(conf, batch[i], &temp_inactive_list[hash]);
6202         }
6203         return batch_size;
6204 }
6205
6206 static void raid5_do_work(struct work_struct *work)
6207 {
6208         struct r5worker *worker = container_of(work, struct r5worker, work);
6209         struct r5worker_group *group = worker->group;
6210         struct r5conf *conf = group->conf;
6211         struct mddev *mddev = conf->mddev;
6212         int group_id = group - conf->worker_groups;
6213         int handled;
6214         struct blk_plug plug;
6215
6216         pr_debug("+++ raid5worker active\n");
6217
6218         blk_start_plug(&plug);
6219         handled = 0;
6220         spin_lock_irq(&conf->device_lock);
6221         while (1) {
6222                 int batch_size, released;
6223
6224                 released = release_stripe_list(conf, worker->temp_inactive_list);
6225
6226                 batch_size = handle_active_stripes(conf, group_id, worker,
6227                                                    worker->temp_inactive_list);
6228                 worker->working = false;
6229                 if (!batch_size && !released)
6230                         break;
6231                 handled += batch_size;
6232                 wait_event_lock_irq(mddev->sb_wait,
6233                         !test_bit(MD_SB_CHANGE_PENDING, &mddev->sb_flags),
6234                         conf->device_lock);
6235         }
6236         pr_debug("%d stripes handled\n", handled);
6237
6238         spin_unlock_irq(&conf->device_lock);
6239
6240         async_tx_issue_pending_all();
6241         blk_finish_plug(&plug);
6242
6243         pr_debug("--- raid5worker inactive\n");
6244 }
6245
6246 /*
6247  * This is our raid5 kernel thread.
6248  *
6249  * We scan the hash table for stripes which can be handled now.
6250  * During the scan, completed stripes are saved for us by the interrupt
6251  * handler, so that they will not have to wait for our next wakeup.
6252  */
6253 static void raid5d(struct md_thread *thread)
6254 {
6255         struct mddev *mddev = thread->mddev;
6256         struct r5conf *conf = mddev->private;
6257         int handled;
6258         struct blk_plug plug;
6259
6260         pr_debug("+++ raid5d active\n");
6261
6262         md_check_recovery(mddev);
6263
6264         blk_start_plug(&plug);
6265         handled = 0;
6266         spin_lock_irq(&conf->device_lock);
6267         while (1) {
6268                 struct bio *bio;
6269                 int batch_size, released;
6270                 unsigned int offset;
6271
6272                 released = release_stripe_list(conf, conf->temp_inactive_list);
6273                 if (released)
6274                         clear_bit(R5_DID_ALLOC, &conf->cache_state);
6275
6276                 if (
6277                     !list_empty(&conf->bitmap_list)) {
6278                         /* Now is a good time to flush some bitmap updates */
6279                         conf->seq_flush++;
6280                         spin_unlock_irq(&conf->device_lock);
6281                         bitmap_unplug(mddev->bitmap);
6282                         spin_lock_irq(&conf->device_lock);
6283                         conf->seq_write = conf->seq_flush;
6284                         activate_bit_delay(conf, conf->temp_inactive_list);
6285                 }
6286                 raid5_activate_delayed(conf);
6287
6288                 while ((bio = remove_bio_from_retry(conf, &offset))) {
6289                         int ok;
6290                         spin_unlock_irq(&conf->device_lock);
6291                         ok = retry_aligned_read(conf, bio, offset);
6292                         spin_lock_irq(&conf->device_lock);
6293                         if (!ok)
6294                                 break;
6295                         handled++;
6296                 }
6297
6298                 batch_size = handle_active_stripes(conf, ANY_GROUP, NULL,
6299                                                    conf->temp_inactive_list);
6300                 if (!batch_size && !released)
6301                         break;
6302                 handled += batch_size;
6303
6304                 if (mddev->sb_flags & ~(1 << MD_SB_CHANGE_PENDING)) {
6305                         spin_unlock_irq(&conf->device_lock);
6306                         md_check_recovery(mddev);
6307                         spin_lock_irq(&conf->device_lock);
6308                 }
6309         }
6310         pr_debug("%d stripes handled\n", handled);
6311
6312         spin_unlock_irq(&conf->device_lock);
6313         if (test_and_clear_bit(R5_ALLOC_MORE, &conf->cache_state) &&
6314             mutex_trylock(&conf->cache_size_mutex)) {
6315                 grow_one_stripe(conf, __GFP_NOWARN);
6316                 /* Set flag even if allocation failed.  This helps
6317                  * slow down allocation requests when mem is short
6318                  */
6319                 set_bit(R5_DID_ALLOC, &conf->cache_state);
6320                 mutex_unlock(&conf->cache_size_mutex);
6321         }
6322
6323         flush_deferred_bios(conf);
6324
6325         r5l_flush_stripe_to_raid(conf->log);
6326
6327         async_tx_issue_pending_all();
6328         blk_finish_plug(&plug);
6329
6330         pr_debug("--- raid5d inactive\n");
6331 }
6332
6333 static ssize_t
6334 raid5_show_stripe_cache_size(struct mddev *mddev, char *page)
6335 {
6336         struct r5conf *conf;
6337         int ret = 0;
6338         spin_lock(&mddev->lock);
6339         conf = mddev->private;
6340         if (conf)
6341                 ret = sprintf(page, "%d\n", conf->min_nr_stripes);
6342         spin_unlock(&mddev->lock);
6343         return ret;
6344 }
6345
6346 int
6347 raid5_set_cache_size(struct mddev *mddev, int size)
6348 {
6349         struct r5conf *conf = mddev->private;
6350
6351         if (size <= 16 || size > 32768)
6352                 return -EINVAL;
6353
6354         conf->min_nr_stripes = size;
6355         mutex_lock(&conf->cache_size_mutex);
6356         while (size < conf->max_nr_stripes &&
6357                drop_one_stripe(conf))
6358                 ;
6359         mutex_unlock(&conf->cache_size_mutex);
6360
6361         md_allow_write(mddev);
6362
6363         mutex_lock(&conf->cache_size_mutex);
6364         while (size > conf->max_nr_stripes)
6365                 if (!grow_one_stripe(conf, GFP_KERNEL))
6366                         break;
6367         mutex_unlock(&conf->cache_size_mutex);
6368
6369         return 0;
6370 }
6371 EXPORT_SYMBOL(raid5_set_cache_size);
6372
6373 static ssize_t
6374 raid5_store_stripe_cache_size(struct mddev *mddev, const char *page, size_t len)
6375 {
6376         struct r5conf *conf;
6377         unsigned long new;
6378         int err;
6379
6380         if (len >= PAGE_SIZE)
6381                 return -EINVAL;
6382         if (kstrtoul(page, 10, &new))
6383                 return -EINVAL;
6384         err = mddev_lock(mddev);
6385         if (err)
6386                 return err;
6387         conf = mddev->private;
6388         if (!conf)
6389                 err = -ENODEV;
6390         else
6391                 err = raid5_set_cache_size(mddev, new);
6392         mddev_unlock(mddev);
6393
6394         return err ?: len;
6395 }
6396
6397 static struct md_sysfs_entry
6398 raid5_stripecache_size = __ATTR(stripe_cache_size, S_IRUGO | S_IWUSR,
6399                                 raid5_show_stripe_cache_size,
6400                                 raid5_store_stripe_cache_size);
6401
6402 static ssize_t
6403 raid5_show_rmw_level(struct mddev  *mddev, char *page)
6404 {
6405         struct r5conf *conf = mddev->private;
6406         if (conf)
6407                 return sprintf(page, "%d\n", conf->rmw_level);
6408         else
6409                 return 0;
6410 }
6411
6412 static ssize_t
6413 raid5_store_rmw_level(struct mddev  *mddev, const char *page, size_t len)
6414 {
6415         struct r5conf *conf = mddev->private;
6416         unsigned long new;
6417
6418         if (!conf)
6419                 return -ENODEV;
6420
6421         if (len >= PAGE_SIZE)
6422                 return -EINVAL;
6423
6424         if (kstrtoul(page, 10, &new))
6425                 return -EINVAL;
6426
6427         if (new != PARITY_DISABLE_RMW && !raid6_call.xor_syndrome)
6428                 return -EINVAL;
6429
6430         if (new != PARITY_DISABLE_RMW &&
6431             new != PARITY_ENABLE_RMW &&
6432             new != PARITY_PREFER_RMW)
6433                 return -EINVAL;
6434
6435         conf->rmw_level = new;
6436         return len;
6437 }
6438
6439 static struct md_sysfs_entry
6440 raid5_rmw_level = __ATTR(rmw_level, S_IRUGO | S_IWUSR,
6441                          raid5_show_rmw_level,
6442                          raid5_store_rmw_level);
6443
6444
6445 static ssize_t
6446 raid5_show_preread_threshold(struct mddev *mddev, char *page)
6447 {
6448         struct r5conf *conf;
6449         int ret = 0;
6450         spin_lock(&mddev->lock);
6451         conf = mddev->private;
6452         if (conf)
6453                 ret = sprintf(page, "%d\n", conf->bypass_threshold);
6454         spin_unlock(&mddev->lock);
6455         return ret;
6456 }
6457
6458 static ssize_t
6459 raid5_store_preread_threshold(struct mddev *mddev, const char *page, size_t len)
6460 {
6461         struct r5conf *conf;
6462         unsigned long new;
6463         int err;
6464
6465         if (len >= PAGE_SIZE)
6466                 return -EINVAL;
6467         if (kstrtoul(page, 10, &new))
6468                 return -EINVAL;
6469
6470         err = mddev_lock(mddev);
6471         if (err)
6472                 return err;
6473         conf = mddev->private;
6474         if (!conf)
6475                 err = -ENODEV;
6476         else if (new > conf->min_nr_stripes)
6477                 err = -EINVAL;
6478         else
6479                 conf->bypass_threshold = new;
6480         mddev_unlock(mddev);
6481         return err ?: len;
6482 }
6483
6484 static struct md_sysfs_entry
6485 raid5_preread_bypass_threshold = __ATTR(preread_bypass_threshold,
6486                                         S_IRUGO | S_IWUSR,
6487                                         raid5_show_preread_threshold,
6488                                         raid5_store_preread_threshold);
6489
6490 static ssize_t
6491 raid5_show_skip_copy(struct mddev *mddev, char *page)
6492 {
6493         struct r5conf *conf;
6494         int ret = 0;
6495         spin_lock(&mddev->lock);
6496         conf = mddev->private;
6497         if (conf)
6498                 ret = sprintf(page, "%d\n", conf->skip_copy);
6499         spin_unlock(&mddev->lock);
6500         return ret;
6501 }
6502
6503 static ssize_t
6504 raid5_store_skip_copy(struct mddev *mddev, const char *page, size_t len)
6505 {
6506         struct r5conf *conf;
6507         unsigned long new;
6508         int err;
6509
6510         if (len >= PAGE_SIZE)
6511                 return -EINVAL;
6512         if (kstrtoul(page, 10, &new))
6513                 return -EINVAL;
6514         new = !!new;
6515
6516         err = mddev_lock(mddev);
6517         if (err)
6518                 return err;
6519         conf = mddev->private;
6520         if (!conf)
6521                 err = -ENODEV;
6522         else if (new != conf->skip_copy) {
6523                 mddev_suspend(mddev);
6524                 conf->skip_copy = new;
6525                 if (new)
6526                         mddev->queue->backing_dev_info->capabilities |=
6527                                 BDI_CAP_STABLE_WRITES;
6528                 else
6529                         mddev->queue->backing_dev_info->capabilities &=
6530                                 ~BDI_CAP_STABLE_WRITES;
6531                 mddev_resume(mddev);
6532         }
6533         mddev_unlock(mddev);
6534         return err ?: len;
6535 }
6536
6537 static struct md_sysfs_entry
6538 raid5_skip_copy = __ATTR(skip_copy, S_IRUGO | S_IWUSR,
6539                                         raid5_show_skip_copy,
6540                                         raid5_store_skip_copy);
6541
6542 static ssize_t
6543 stripe_cache_active_show(struct mddev *mddev, char *page)
6544 {
6545         struct r5conf *conf = mddev->private;
6546         if (conf)
6547                 return sprintf(page, "%d\n", atomic_read(&conf->active_stripes));
6548         else
6549                 return 0;
6550 }
6551
6552 static struct md_sysfs_entry
6553 raid5_stripecache_active = __ATTR_RO(stripe_cache_active);
6554
6555 static ssize_t
6556 raid5_show_group_thread_cnt(struct mddev *mddev, char *page)
6557 {
6558         struct r5conf *conf;
6559         int ret = 0;
6560         spin_lock(&mddev->lock);
6561         conf = mddev->private;
6562         if (conf)
6563                 ret = sprintf(page, "%d\n", conf->worker_cnt_per_group);
6564         spin_unlock(&mddev->lock);
6565         return ret;
6566 }
6567
6568 static int alloc_thread_groups(struct r5conf *conf, int cnt,
6569                                int *group_cnt,
6570                                int *worker_cnt_per_group,
6571                                struct r5worker_group **worker_groups);
6572 static ssize_t
6573 raid5_store_group_thread_cnt(struct mddev *mddev, const char *page, size_t len)
6574 {
6575         struct r5conf *conf;
6576         unsigned long new;
6577         int err;
6578         struct r5worker_group *new_groups, *old_groups;
6579         int group_cnt, worker_cnt_per_group;
6580
6581         if (len >= PAGE_SIZE)
6582                 return -EINVAL;
6583         if (kstrtoul(page, 10, &new))
6584                 return -EINVAL;
6585
6586         err = mddev_lock(mddev);
6587         if (err)
6588                 return err;
6589         conf = mddev->private;
6590         if (!conf)
6591                 err = -ENODEV;
6592         else if (new != conf->worker_cnt_per_group) {
6593                 mddev_suspend(mddev);
6594
6595                 old_groups = conf->worker_groups;
6596                 if (old_groups)
6597                         flush_workqueue(raid5_wq);
6598
6599                 err = alloc_thread_groups(conf, new,
6600                                           &group_cnt, &worker_cnt_per_group,
6601                                           &new_groups);
6602                 if (!err) {
6603                         spin_lock_irq(&conf->device_lock);
6604                         conf->group_cnt = group_cnt;
6605                         conf->worker_cnt_per_group = worker_cnt_per_group;
6606                         conf->worker_groups = new_groups;
6607                         spin_unlock_irq(&conf->device_lock);
6608
6609                         if (old_groups)
6610                                 kfree(old_groups[0].workers);
6611                         kfree(old_groups);
6612                 }
6613                 mddev_resume(mddev);
6614         }
6615         mddev_unlock(mddev);
6616
6617         return err ?: len;
6618 }
6619
6620 static struct md_sysfs_entry
6621 raid5_group_thread_cnt = __ATTR(group_thread_cnt, S_IRUGO | S_IWUSR,
6622                                 raid5_show_group_thread_cnt,
6623                                 raid5_store_group_thread_cnt);
6624
6625 static struct attribute *raid5_attrs[] =  {
6626         &raid5_stripecache_size.attr,
6627         &raid5_stripecache_active.attr,
6628         &raid5_preread_bypass_threshold.attr,
6629         &raid5_group_thread_cnt.attr,
6630         &raid5_skip_copy.attr,
6631         &raid5_rmw_level.attr,
6632         &r5c_journal_mode.attr,
6633         NULL,
6634 };
6635 static struct attribute_group raid5_attrs_group = {
6636         .name = NULL,
6637         .attrs = raid5_attrs,
6638 };
6639
6640 static int alloc_thread_groups(struct r5conf *conf, int cnt,
6641                                int *group_cnt,
6642                                int *worker_cnt_per_group,
6643                                struct r5worker_group **worker_groups)
6644 {
6645         int i, j, k;
6646         ssize_t size;
6647         struct r5worker *workers;
6648
6649         *worker_cnt_per_group = cnt;
6650         if (cnt == 0) {
6651                 *group_cnt = 0;
6652                 *worker_groups = NULL;
6653                 return 0;
6654         }
6655         *group_cnt = num_possible_nodes();
6656         size = sizeof(struct r5worker) * cnt;
6657         workers = kzalloc(size * *group_cnt, GFP_NOIO);
6658         *worker_groups = kzalloc(sizeof(struct r5worker_group) *
6659                                 *group_cnt, GFP_NOIO);
6660         if (!*worker_groups || !workers) {
6661                 kfree(workers);
6662                 kfree(*worker_groups);
6663                 return -ENOMEM;
6664         }
6665
6666         for (i = 0; i < *group_cnt; i++) {
6667                 struct r5worker_group *group;
6668
6669                 group = &(*worker_groups)[i];
6670                 INIT_LIST_HEAD(&group->handle_list);
6671                 INIT_LIST_HEAD(&group->loprio_list);
6672                 group->conf = conf;
6673                 group->workers = workers + i * cnt;
6674
6675                 for (j = 0; j < cnt; j++) {
6676                         struct r5worker *worker = group->workers + j;
6677                         worker->group = group;
6678                         INIT_WORK(&worker->work, raid5_do_work);
6679
6680                         for (k = 0; k < NR_STRIPE_HASH_LOCKS; k++)
6681                                 INIT_LIST_HEAD(worker->temp_inactive_list + k);
6682                 }
6683         }
6684
6685         return 0;
6686 }
6687
6688 static void free_thread_groups(struct r5conf *conf)
6689 {
6690         if (conf->worker_groups)
6691                 kfree(conf->worker_groups[0].workers);
6692         kfree(conf->worker_groups);
6693         conf->worker_groups = NULL;
6694 }
6695
6696 static sector_t
6697 raid5_size(struct mddev *mddev, sector_t sectors, int raid_disks)
6698 {
6699         struct r5conf *conf = mddev->private;
6700
6701         if (!sectors)
6702                 sectors = mddev->dev_sectors;
6703         if (!raid_disks)
6704                 /* size is defined by the smallest of previous and new size */
6705                 raid_disks = min(conf->raid_disks, conf->previous_raid_disks);
6706
6707         sectors &= ~((sector_t)conf->chunk_sectors - 1);
6708         sectors &= ~((sector_t)conf->prev_chunk_sectors - 1);
6709         return sectors * (raid_disks - conf->max_degraded);
6710 }
6711
6712 static void free_scratch_buffer(struct r5conf *conf, struct raid5_percpu *percpu)
6713 {
6714         safe_put_page(percpu->spare_page);
6715         if (percpu->scribble)
6716                 flex_array_free(percpu->scribble);
6717         percpu->spare_page = NULL;
6718         percpu->scribble = NULL;
6719 }
6720
6721 static int alloc_scratch_buffer(struct r5conf *conf, struct raid5_percpu *percpu)
6722 {
6723         if (conf->level == 6 && !percpu->spare_page)
6724                 percpu->spare_page = alloc_page(GFP_KERNEL);
6725         if (!percpu->scribble)
6726                 percpu->scribble = scribble_alloc(max(conf->raid_disks,
6727                                                       conf->previous_raid_disks),
6728                                                   max(conf->chunk_sectors,
6729                                                       conf->prev_chunk_sectors)
6730                                                    / STRIPE_SECTORS,
6731                                                   GFP_KERNEL);
6732
6733         if (!percpu->scribble || (conf->level == 6 && !percpu->spare_page)) {
6734                 free_scratch_buffer(conf, percpu);
6735                 return -ENOMEM;
6736         }
6737
6738         return 0;
6739 }
6740
6741 static int raid456_cpu_dead(unsigned int cpu, struct hlist_node *node)
6742 {
6743         struct r5conf *conf = hlist_entry_safe(node, struct r5conf, node);
6744
6745         free_scratch_buffer(conf, per_cpu_ptr(conf->percpu, cpu));
6746         return 0;
6747 }
6748
6749 static void raid5_free_percpu(struct r5conf *conf)
6750 {
6751         if (!conf->percpu)
6752                 return;
6753
6754         cpuhp_state_remove_instance(CPUHP_MD_RAID5_PREPARE, &conf->node);
6755         free_percpu(conf->percpu);
6756 }
6757
6758 static void free_conf(struct r5conf *conf)
6759 {
6760         int i;
6761
6762         log_exit(conf);
6763
6764         if (conf->shrinker.nr_deferred)
6765                 unregister_shrinker(&conf->shrinker);
6766
6767         free_thread_groups(conf);
6768         shrink_stripes(conf);
6769         raid5_free_percpu(conf);
6770         for (i = 0; i < conf->pool_size; i++)
6771                 if (conf->disks[i].extra_page)
6772                         put_page(conf->disks[i].extra_page);
6773         kfree(conf->disks);
6774         if (conf->bio_split)
6775                 bioset_free(conf->bio_split);
6776         kfree(conf->stripe_hashtbl);
6777         kfree(conf->pending_data);
6778         kfree(conf);
6779 }
6780
6781 static int raid456_cpu_up_prepare(unsigned int cpu, struct hlist_node *node)
6782 {
6783         struct r5conf *conf = hlist_entry_safe(node, struct r5conf, node);
6784         struct raid5_percpu *percpu = per_cpu_ptr(conf->percpu, cpu);
6785
6786         if (alloc_scratch_buffer(conf, percpu)) {
6787                 pr_warn("%s: failed memory allocation for cpu%u\n",
6788                         __func__, cpu);
6789                 return -ENOMEM;
6790         }
6791         return 0;
6792 }
6793
6794 static int raid5_alloc_percpu(struct r5conf *conf)
6795 {
6796         int err = 0;
6797
6798         conf->percpu = alloc_percpu(struct raid5_percpu);
6799         if (!conf->percpu)
6800                 return -ENOMEM;
6801
6802         err = cpuhp_state_add_instance(CPUHP_MD_RAID5_PREPARE, &conf->node);
6803         if (!err) {
6804                 conf->scribble_disks = max(conf->raid_disks,
6805                         conf->previous_raid_disks);
6806                 conf->scribble_sectors = max(conf->chunk_sectors,
6807                         conf->prev_chunk_sectors);
6808         }
6809         return err;
6810 }
6811
6812 static unsigned long raid5_cache_scan(struct shrinker *shrink,
6813                                       struct shrink_control *sc)
6814 {
6815         struct r5conf *conf = container_of(shrink, struct r5conf, shrinker);
6816         unsigned long ret = SHRINK_STOP;
6817
6818         if (mutex_trylock(&conf->cache_size_mutex)) {
6819                 ret= 0;
6820                 while (ret < sc->nr_to_scan &&
6821                        conf->max_nr_stripes > conf->min_nr_stripes) {
6822                         if (drop_one_stripe(conf) == 0) {
6823                                 ret = SHRINK_STOP;
6824                                 break;
6825                         }
6826                         ret++;
6827                 }
6828                 mutex_unlock(&conf->cache_size_mutex);
6829         }
6830         return ret;
6831 }
6832
6833 static unsigned long raid5_cache_count(struct shrinker *shrink,
6834                                        struct shrink_control *sc)
6835 {
6836         struct r5conf *conf = container_of(shrink, struct r5conf, shrinker);
6837
6838         if (conf->max_nr_stripes < conf->min_nr_stripes)
6839                 /* unlikely, but not impossible */
6840                 return 0;
6841         return conf->max_nr_stripes - conf->min_nr_stripes;
6842 }
6843
6844 static struct r5conf *setup_conf(struct mddev *mddev)
6845 {
6846         struct r5conf *conf;
6847         int raid_disk, memory, max_disks;
6848         struct md_rdev *rdev;
6849         struct disk_info *disk;
6850         char pers_name[6];
6851         int i;
6852         int group_cnt, worker_cnt_per_group;
6853         struct r5worker_group *new_group;
6854
6855         if (mddev->new_level != 5
6856             && mddev->new_level != 4
6857             && mddev->new_level != 6) {
6858                 pr_warn("md/raid:%s: raid level not set to 4/5/6 (%d)\n",
6859                         mdname(mddev), mddev->new_level);
6860                 return ERR_PTR(-EIO);
6861         }
6862         if ((mddev->new_level == 5
6863              && !algorithm_valid_raid5(mddev->new_layout)) ||
6864             (mddev->new_level == 6
6865              && !algorithm_valid_raid6(mddev->new_layout))) {
6866                 pr_warn("md/raid:%s: layout %d not supported\n",
6867                         mdname(mddev), mddev->new_layout);
6868                 return ERR_PTR(-EIO);
6869         }
6870         if (mddev->new_level == 6 && mddev->raid_disks < 4) {
6871                 pr_warn("md/raid:%s: not enough configured devices (%d, minimum 4)\n",
6872                         mdname(mddev), mddev->raid_disks);
6873                 return ERR_PTR(-EINVAL);
6874         }
6875
6876         if (!mddev->new_chunk_sectors ||
6877             (mddev->new_chunk_sectors << 9) % PAGE_SIZE ||
6878             !is_power_of_2(mddev->new_chunk_sectors)) {
6879                 pr_warn("md/raid:%s: invalid chunk size %d\n",
6880                         mdname(mddev), mddev->new_chunk_sectors << 9);
6881                 return ERR_PTR(-EINVAL);
6882         }
6883
6884         conf = kzalloc(sizeof(struct r5conf), GFP_KERNEL);
6885         if (conf == NULL)
6886                 goto abort;
6887         INIT_LIST_HEAD(&conf->free_list);
6888         INIT_LIST_HEAD(&conf->pending_list);
6889         conf->pending_data = kzalloc(sizeof(struct r5pending_data) *
6890                 PENDING_IO_MAX, GFP_KERNEL);
6891         if (!conf->pending_data)
6892                 goto abort;
6893         for (i = 0; i < PENDING_IO_MAX; i++)
6894                 list_add(&conf->pending_data[i].sibling, &conf->free_list);
6895         /* Don't enable multi-threading by default*/
6896         if (!alloc_thread_groups(conf, 0, &group_cnt, &worker_cnt_per_group,
6897                                  &new_group)) {
6898                 conf->group_cnt = group_cnt;
6899                 conf->worker_cnt_per_group = worker_cnt_per_group;
6900                 conf->worker_groups = new_group;
6901         } else
6902                 goto abort;
6903         spin_lock_init(&conf->device_lock);
6904         seqcount_init(&conf->gen_lock);
6905         mutex_init(&conf->cache_size_mutex);
6906         init_waitqueue_head(&conf->wait_for_quiescent);
6907         init_waitqueue_head(&conf->wait_for_stripe);
6908         init_waitqueue_head(&conf->wait_for_overlap);
6909         INIT_LIST_HEAD(&conf->handle_list);
6910         INIT_LIST_HEAD(&conf->loprio_list);
6911         INIT_LIST_HEAD(&conf->hold_list);
6912         INIT_LIST_HEAD(&conf->delayed_list);
6913         INIT_LIST_HEAD(&conf->bitmap_list);
6914         init_llist_head(&conf->released_stripes);
6915         atomic_set(&conf->active_stripes, 0);
6916         atomic_set(&conf->preread_active_stripes, 0);
6917         atomic_set(&conf->active_aligned_reads, 0);
6918         spin_lock_init(&conf->pending_bios_lock);
6919         conf->batch_bio_dispatch = true;
6920         rdev_for_each(rdev, mddev) {
6921                 if (test_bit(Journal, &rdev->flags))
6922                         continue;
6923                 if (blk_queue_nonrot(bdev_get_queue(rdev->bdev))) {
6924                         conf->batch_bio_dispatch = false;
6925                         break;
6926                 }
6927         }
6928
6929         conf->bypass_threshold = BYPASS_THRESHOLD;
6930         conf->recovery_disabled = mddev->recovery_disabled - 1;
6931
6932         conf->raid_disks = mddev->raid_disks;
6933         if (mddev->reshape_position == MaxSector)
6934                 conf->previous_raid_disks = mddev->raid_disks;
6935         else
6936                 conf->previous_raid_disks = mddev->raid_disks - mddev->delta_disks;
6937         max_disks = max(conf->raid_disks, conf->previous_raid_disks);
6938
6939         conf->disks = kzalloc(max_disks * sizeof(struct disk_info),
6940                               GFP_KERNEL);
6941
6942         if (!conf->disks)
6943                 goto abort;
6944
6945         for (i = 0; i < max_disks; i++) {
6946                 conf->disks[i].extra_page = alloc_page(GFP_KERNEL);
6947                 if (!conf->disks[i].extra_page)
6948                         goto abort;
6949         }
6950
6951         conf->bio_split = bioset_create(BIO_POOL_SIZE, 0, 0);
6952         if (!conf->bio_split)
6953                 goto abort;
6954         conf->mddev = mddev;
6955
6956         if ((conf->stripe_hashtbl = kzalloc(PAGE_SIZE, GFP_KERNEL)) == NULL)
6957                 goto abort;
6958
6959         /* We init hash_locks[0] separately to that it can be used
6960          * as the reference lock in the spin_lock_nest_lock() call
6961          * in lock_all_device_hash_locks_irq in order to convince
6962          * lockdep that we know what we are doing.
6963          */
6964         spin_lock_init(conf->hash_locks);
6965         for (i = 1; i < NR_STRIPE_HASH_LOCKS; i++)
6966                 spin_lock_init(conf->hash_locks + i);
6967
6968         for (i = 0; i < NR_STRIPE_HASH_LOCKS; i++)
6969                 INIT_LIST_HEAD(conf->inactive_list + i);
6970
6971         for (i = 0; i < NR_STRIPE_HASH_LOCKS; i++)
6972                 INIT_LIST_HEAD(conf->temp_inactive_list + i);
6973
6974         atomic_set(&conf->r5c_cached_full_stripes, 0);
6975         INIT_LIST_HEAD(&conf->r5c_full_stripe_list);
6976         atomic_set(&conf->r5c_cached_partial_stripes, 0);
6977         INIT_LIST_HEAD(&conf->r5c_partial_stripe_list);
6978         atomic_set(&conf->r5c_flushing_full_stripes, 0);
6979         atomic_set(&conf->r5c_flushing_partial_stripes, 0);
6980
6981         conf->level = mddev->new_level;
6982         conf->chunk_sectors = mddev->new_chunk_sectors;
6983         if (raid5_alloc_percpu(conf) != 0)
6984                 goto abort;
6985
6986         pr_debug("raid456: run(%s) called.\n", mdname(mddev));
6987
6988         rdev_for_each(rdev, mddev) {
6989                 raid_disk = rdev->raid_disk;
6990                 if (raid_disk >= max_disks
6991                     || raid_disk < 0 || test_bit(Journal, &rdev->flags))
6992                         continue;
6993                 disk = conf->disks + raid_disk;
6994
6995                 if (test_bit(Replacement, &rdev->flags)) {
6996                         if (disk->replacement)
6997                                 goto abort;
6998                         disk->replacement = rdev;
6999                 } else {
7000                         if (disk->rdev)
7001                                 goto abort;
7002                         disk->rdev = rdev;
7003                 }
7004
7005                 if (test_bit(In_sync, &rdev->flags)) {
7006                         char b[BDEVNAME_SIZE];
7007                         pr_info("md/raid:%s: device %s operational as raid disk %d\n",
7008                                 mdname(mddev), bdevname(rdev->bdev, b), raid_disk);
7009                 } else if (rdev->saved_raid_disk != raid_disk)
7010                         /* Cannot rely on bitmap to complete recovery */
7011                         conf->fullsync = 1;
7012         }
7013
7014         conf->level = mddev->new_level;
7015         if (conf->level == 6) {
7016                 conf->max_degraded = 2;
7017                 if (raid6_call.xor_syndrome)
7018                         conf->rmw_level = PARITY_ENABLE_RMW;
7019                 else
7020                         conf->rmw_level = PARITY_DISABLE_RMW;
7021         } else {
7022                 conf->max_degraded = 1;
7023                 conf->rmw_level = PARITY_ENABLE_RMW;
7024         }
7025         conf->algorithm = mddev->new_layout;
7026         conf->reshape_progress = mddev->reshape_position;
7027         if (conf->reshape_progress != MaxSector) {
7028                 conf->prev_chunk_sectors = mddev->chunk_sectors;
7029                 conf->prev_algo = mddev->layout;
7030         } else {
7031                 conf->prev_chunk_sectors = conf->chunk_sectors;
7032                 conf->prev_algo = conf->algorithm;
7033         }
7034
7035         conf->min_nr_stripes = NR_STRIPES;
7036         if (mddev->reshape_position != MaxSector) {
7037                 int stripes = max_t(int,
7038                         ((mddev->chunk_sectors << 9) / STRIPE_SIZE) * 4,
7039                         ((mddev->new_chunk_sectors << 9) / STRIPE_SIZE) * 4);
7040                 conf->min_nr_stripes = max(NR_STRIPES, stripes);
7041                 if (conf->min_nr_stripes != NR_STRIPES)
7042                         pr_info("md/raid:%s: force stripe size %d for reshape\n",
7043                                 mdname(mddev), conf->min_nr_stripes);
7044         }
7045         memory = conf->min_nr_stripes * (sizeof(struct stripe_head) +
7046                  max_disks * ((sizeof(struct bio) + PAGE_SIZE))) / 1024;
7047         atomic_set(&conf->empty_inactive_list_nr, NR_STRIPE_HASH_LOCKS);
7048         if (grow_stripes(conf, conf->min_nr_stripes)) {
7049                 pr_warn("md/raid:%s: couldn't allocate %dkB for buffers\n",
7050                         mdname(mddev), memory);
7051                 goto abort;
7052         } else
7053                 pr_debug("md/raid:%s: allocated %dkB\n", mdname(mddev), memory);
7054         /*
7055          * Losing a stripe head costs more than the time to refill it,
7056          * it reduces the queue depth and so can hurt throughput.
7057          * So set it rather large, scaled by number of devices.
7058          */
7059         conf->shrinker.seeks = DEFAULT_SEEKS * conf->raid_disks * 4;
7060         conf->shrinker.scan_objects = raid5_cache_scan;
7061         conf->shrinker.count_objects = raid5_cache_count;
7062         conf->shrinker.batch = 128;
7063         conf->shrinker.flags = 0;
7064         if (register_shrinker(&conf->shrinker)) {
7065                 pr_warn("md/raid:%s: couldn't register shrinker.\n",
7066                         mdname(mddev));
7067                 goto abort;
7068         }
7069
7070         sprintf(pers_name, "raid%d", mddev->new_level);
7071         conf->thread = md_register_thread(raid5d, mddev, pers_name);
7072         if (!conf->thread) {
7073                 pr_warn("md/raid:%s: couldn't allocate thread.\n",
7074                         mdname(mddev));
7075                 goto abort;
7076         }
7077
7078         return conf;
7079
7080  abort:
7081         if (conf) {
7082                 free_conf(conf);
7083                 return ERR_PTR(-EIO);
7084         } else
7085                 return ERR_PTR(-ENOMEM);
7086 }
7087
7088 static int only_parity(int raid_disk, int algo, int raid_disks, int max_degraded)
7089 {
7090         switch (algo) {
7091         case ALGORITHM_PARITY_0:
7092                 if (raid_disk < max_degraded)
7093                         return 1;
7094                 break;
7095         case ALGORITHM_PARITY_N:
7096                 if (raid_disk >= raid_disks - max_degraded)
7097                         return 1;
7098                 break;
7099         case ALGORITHM_PARITY_0_6:
7100                 if (raid_disk == 0 ||
7101                     raid_disk == raid_disks - 1)
7102                         return 1;
7103                 break;
7104         case ALGORITHM_LEFT_ASYMMETRIC_6:
7105         case ALGORITHM_RIGHT_ASYMMETRIC_6:
7106         case ALGORITHM_LEFT_SYMMETRIC_6:
7107         case ALGORITHM_RIGHT_SYMMETRIC_6:
7108                 if (raid_disk == raid_disks - 1)
7109                         return 1;
7110         }
7111         return 0;
7112 }
7113
7114 static int raid5_run(struct mddev *mddev)
7115 {
7116         struct r5conf *conf;
7117         int working_disks = 0;
7118         int dirty_parity_disks = 0;
7119         struct md_rdev *rdev;
7120         struct md_rdev *journal_dev = NULL;
7121         sector_t reshape_offset = 0;
7122         int i;
7123         long long min_offset_diff = 0;
7124         int first = 1;
7125
7126         if (mddev_init_writes_pending(mddev) < 0)
7127                 return -ENOMEM;
7128
7129         if (mddev->recovery_cp != MaxSector)
7130                 pr_notice("md/raid:%s: not clean -- starting background reconstruction\n",
7131                           mdname(mddev));
7132
7133         rdev_for_each(rdev, mddev) {
7134                 long long diff;
7135
7136                 if (test_bit(Journal, &rdev->flags)) {
7137                         journal_dev = rdev;
7138                         continue;
7139                 }
7140                 if (rdev->raid_disk < 0)
7141                         continue;
7142                 diff = (rdev->new_data_offset - rdev->data_offset);
7143                 if (first) {
7144                         min_offset_diff = diff;
7145                         first = 0;
7146                 } else if (mddev->reshape_backwards &&
7147                          diff < min_offset_diff)
7148                         min_offset_diff = diff;
7149                 else if (!mddev->reshape_backwards &&
7150                          diff > min_offset_diff)
7151                         min_offset_diff = diff;
7152         }
7153
7154         if (mddev->reshape_position != MaxSector) {
7155                 /* Check that we can continue the reshape.
7156                  * Difficulties arise if the stripe we would write to
7157                  * next is at or after the stripe we would read from next.
7158                  * For a reshape that changes the number of devices, this
7159                  * is only possible for a very short time, and mdadm makes
7160                  * sure that time appears to have past before assembling
7161                  * the array.  So we fail if that time hasn't passed.
7162                  * For a reshape that keeps the number of devices the same
7163                  * mdadm must be monitoring the reshape can keeping the
7164                  * critical areas read-only and backed up.  It will start
7165                  * the array in read-only mode, so we check for that.
7166                  */
7167                 sector_t here_new, here_old;
7168                 int old_disks;
7169                 int max_degraded = (mddev->level == 6 ? 2 : 1);
7170                 int chunk_sectors;
7171                 int new_data_disks;
7172
7173                 if (journal_dev) {
7174                         pr_warn("md/raid:%s: don't support reshape with journal - aborting.\n",
7175                                 mdname(mddev));
7176                         return -EINVAL;
7177                 }
7178
7179                 if (mddev->new_level != mddev->level) {
7180                         pr_warn("md/raid:%s: unsupported reshape required - aborting.\n",
7181                                 mdname(mddev));
7182                         return -EINVAL;
7183                 }
7184                 old_disks = mddev->raid_disks - mddev->delta_disks;
7185                 /* reshape_position must be on a new-stripe boundary, and one
7186                  * further up in new geometry must map after here in old
7187                  * geometry.
7188                  * If the chunk sizes are different, then as we perform reshape
7189                  * in units of the largest of the two, reshape_position needs
7190                  * be a multiple of the largest chunk size times new data disks.
7191                  */
7192                 here_new = mddev->reshape_position;
7193                 chunk_sectors = max(mddev->chunk_sectors, mddev->new_chunk_sectors);
7194                 new_data_disks = mddev->raid_disks - max_degraded;
7195                 if (sector_div(here_new, chunk_sectors * new_data_disks)) {
7196                         pr_warn("md/raid:%s: reshape_position not on a stripe boundary\n",
7197                                 mdname(mddev));
7198                         return -EINVAL;
7199                 }
7200                 reshape_offset = here_new * chunk_sectors;
7201                 /* here_new is the stripe we will write to */
7202                 here_old = mddev->reshape_position;
7203                 sector_div(here_old, chunk_sectors * (old_disks-max_degraded));
7204                 /* here_old is the first stripe that we might need to read
7205                  * from */
7206                 if (mddev->delta_disks == 0) {
7207                         /* We cannot be sure it is safe to start an in-place
7208                          * reshape.  It is only safe if user-space is monitoring
7209                          * and taking constant backups.
7210                          * mdadm always starts a situation like this in
7211                          * readonly mode so it can take control before
7212                          * allowing any writes.  So just check for that.
7213                          */
7214                         if (abs(min_offset_diff) >= mddev->chunk_sectors &&
7215                             abs(min_offset_diff) >= mddev->new_chunk_sectors)
7216                                 /* not really in-place - so OK */;
7217                         else if (mddev->ro == 0) {
7218                                 pr_warn("md/raid:%s: in-place reshape must be started in read-only mode - aborting\n",
7219                                         mdname(mddev));
7220                                 return -EINVAL;
7221                         }
7222                 } else if (mddev->reshape_backwards
7223                     ? (here_new * chunk_sectors + min_offset_diff <=
7224                        here_old * chunk_sectors)
7225                     : (here_new * chunk_sectors >=
7226                        here_old * chunk_sectors + (-min_offset_diff))) {
7227                         /* Reading from the same stripe as writing to - bad */
7228                         pr_warn("md/raid:%s: reshape_position too early for auto-recovery - aborting.\n",
7229                                 mdname(mddev));
7230                         return -EINVAL;
7231                 }
7232                 pr_debug("md/raid:%s: reshape will continue\n", mdname(mddev));
7233                 /* OK, we should be able to continue; */
7234         } else {
7235                 BUG_ON(mddev->level != mddev->new_level);
7236                 BUG_ON(mddev->layout != mddev->new_layout);
7237                 BUG_ON(mddev->chunk_sectors != mddev->new_chunk_sectors);
7238                 BUG_ON(mddev->delta_disks != 0);
7239         }
7240
7241         if (test_bit(MD_HAS_JOURNAL, &mddev->flags) &&
7242             test_bit(MD_HAS_PPL, &mddev->flags)) {
7243                 pr_warn("md/raid:%s: using journal device and PPL not allowed - disabling PPL\n",
7244                         mdname(mddev));
7245                 clear_bit(MD_HAS_PPL, &mddev->flags);
7246         }
7247
7248         if (mddev->private == NULL)
7249                 conf = setup_conf(mddev);
7250         else
7251                 conf = mddev->private;
7252
7253         if (IS_ERR(conf))
7254                 return PTR_ERR(conf);
7255
7256         if (test_bit(MD_HAS_JOURNAL, &mddev->flags)) {
7257                 if (!journal_dev) {
7258                         pr_warn("md/raid:%s: journal disk is missing, force array readonly\n",
7259                                 mdname(mddev));
7260                         mddev->ro = 1;
7261                         set_disk_ro(mddev->gendisk, 1);
7262                 } else if (mddev->recovery_cp == MaxSector)
7263                         set_bit(MD_JOURNAL_CLEAN, &mddev->flags);
7264         }
7265
7266         conf->min_offset_diff = min_offset_diff;
7267         mddev->thread = conf->thread;
7268         conf->thread = NULL;
7269         mddev->private = conf;
7270
7271         for (i = 0; i < conf->raid_disks && conf->previous_raid_disks;
7272              i++) {
7273                 rdev = conf->disks[i].rdev;
7274                 if (!rdev && conf->disks[i].replacement) {
7275                         /* The replacement is all we have yet */
7276                         rdev = conf->disks[i].replacement;
7277                         conf->disks[i].replacement = NULL;
7278                         clear_bit(Replacement, &rdev->flags);
7279                         conf->disks[i].rdev = rdev;
7280                 }
7281                 if (!rdev)
7282                         continue;
7283                 if (conf->disks[i].replacement &&
7284                     conf->reshape_progress != MaxSector) {
7285                         /* replacements and reshape simply do not mix. */
7286                         pr_warn("md: cannot handle concurrent replacement and reshape.\n");
7287                         goto abort;
7288                 }
7289                 if (test_bit(In_sync, &rdev->flags)) {
7290                         working_disks++;
7291                         continue;
7292                 }
7293                 /* This disc is not fully in-sync.  However if it
7294                  * just stored parity (beyond the recovery_offset),
7295                  * when we don't need to be concerned about the
7296                  * array being dirty.
7297                  * When reshape goes 'backwards', we never have
7298                  * partially completed devices, so we only need
7299                  * to worry about reshape going forwards.
7300                  */
7301                 /* Hack because v0.91 doesn't store recovery_offset properly. */
7302                 if (mddev->major_version == 0 &&
7303                     mddev->minor_version > 90)
7304                         rdev->recovery_offset = reshape_offset;
7305
7306                 if (rdev->recovery_offset < reshape_offset) {
7307                         /* We need to check old and new layout */
7308                         if (!only_parity(rdev->raid_disk,
7309                                          conf->algorithm,
7310                                          conf->raid_disks,
7311                                          conf->max_degraded))
7312                                 continue;
7313                 }
7314                 if (!only_parity(rdev->raid_disk,
7315                                  conf->prev_algo,
7316                                  conf->previous_raid_disks,
7317                                  conf->max_degraded))
7318                         continue;
7319                 dirty_parity_disks++;
7320         }
7321
7322         /*
7323          * 0 for a fully functional array, 1 or 2 for a degraded array.
7324          */
7325         mddev->degraded = raid5_calc_degraded(conf);
7326
7327         if (has_failed(conf)) {
7328                 pr_crit("md/raid:%s: not enough operational devices (%d/%d failed)\n",
7329                         mdname(mddev), mddev->degraded, conf->raid_disks);
7330                 goto abort;
7331         }
7332
7333         /* device size must be a multiple of chunk size */
7334         mddev->dev_sectors &= ~(mddev->chunk_sectors - 1);
7335         mddev->resync_max_sectors = mddev->dev_sectors;
7336
7337         if (mddev->degraded > dirty_parity_disks &&
7338             mddev->recovery_cp != MaxSector) {
7339                 if (test_bit(MD_HAS_PPL, &mddev->flags))
7340                         pr_crit("md/raid:%s: starting dirty degraded array with PPL.\n",
7341                                 mdname(mddev));
7342                 else if (mddev->ok_start_degraded)
7343                         pr_crit("md/raid:%s: starting dirty degraded array - data corruption possible.\n",
7344                                 mdname(mddev));
7345                 else {
7346                         pr_crit("md/raid:%s: cannot start dirty degraded array.\n",
7347                                 mdname(mddev));
7348                         goto abort;
7349                 }
7350         }
7351
7352         pr_info("md/raid:%s: raid level %d active with %d out of %d devices, algorithm %d\n",
7353                 mdname(mddev), conf->level,
7354                 mddev->raid_disks-mddev->degraded, mddev->raid_disks,
7355                 mddev->new_layout);
7356
7357         print_raid5_conf(conf);
7358
7359         if (conf->reshape_progress != MaxSector) {
7360                 conf->reshape_safe = conf->reshape_progress;
7361                 atomic_set(&conf->reshape_stripes, 0);
7362                 clear_bit(MD_RECOVERY_SYNC, &mddev->recovery);
7363                 clear_bit(MD_RECOVERY_CHECK, &mddev->recovery);
7364                 set_bit(MD_RECOVERY_RESHAPE, &mddev->recovery);
7365                 set_bit(MD_RECOVERY_RUNNING, &mddev->recovery);
7366                 mddev->sync_thread = md_register_thread(md_do_sync, mddev,
7367                                                         "reshape");
7368         }
7369
7370         /* Ok, everything is just fine now */
7371         if (mddev->to_remove == &raid5_attrs_group)
7372                 mddev->to_remove = NULL;
7373         else if (mddev->kobj.sd &&
7374             sysfs_create_group(&mddev->kobj, &raid5_attrs_group))
7375                 pr_warn("raid5: failed to create sysfs attributes for %s\n",
7376                         mdname(mddev));
7377         md_set_array_sectors(mddev, raid5_size(mddev, 0, 0));
7378
7379         if (mddev->queue) {
7380                 int chunk_size;
7381                 /* read-ahead size must cover two whole stripes, which
7382                  * is 2 * (datadisks) * chunksize where 'n' is the
7383                  * number of raid devices
7384                  */
7385                 int data_disks = conf->previous_raid_disks - conf->max_degraded;
7386                 int stripe = data_disks *
7387                         ((mddev->chunk_sectors << 9) / PAGE_SIZE);
7388                 if (mddev->queue->backing_dev_info->ra_pages < 2 * stripe)
7389                         mddev->queue->backing_dev_info->ra_pages = 2 * stripe;
7390
7391                 chunk_size = mddev->chunk_sectors << 9;
7392                 blk_queue_io_min(mddev->queue, chunk_size);
7393                 blk_queue_io_opt(mddev->queue, chunk_size *
7394                                  (conf->raid_disks - conf->max_degraded));
7395                 mddev->queue->limits.raid_partial_stripes_expensive = 1;
7396                 /*
7397                  * We can only discard a whole stripe. It doesn't make sense to
7398                  * discard data disk but write parity disk
7399                  */
7400                 stripe = stripe * PAGE_SIZE;
7401                 /* Round up to power of 2, as discard handling
7402                  * currently assumes that */
7403                 while ((stripe-1) & stripe)
7404                         stripe = (stripe | (stripe-1)) + 1;
7405                 mddev->queue->limits.discard_alignment = stripe;
7406                 mddev->queue->limits.discard_granularity = stripe;
7407
7408                 blk_queue_max_write_same_sectors(mddev->queue, 0);
7409                 blk_queue_max_write_zeroes_sectors(mddev->queue, 0);
7410
7411                 rdev_for_each(rdev, mddev) {
7412                         disk_stack_limits(mddev->gendisk, rdev->bdev,
7413                                           rdev->data_offset << 9);
7414                         disk_stack_limits(mddev->gendisk, rdev->bdev,
7415                                           rdev->new_data_offset << 9);
7416                 }
7417
7418                 /*
7419                  * zeroing is required, otherwise data
7420                  * could be lost. Consider a scenario: discard a stripe
7421                  * (the stripe could be inconsistent if
7422                  * discard_zeroes_data is 0); write one disk of the
7423                  * stripe (the stripe could be inconsistent again
7424                  * depending on which disks are used to calculate
7425                  * parity); the disk is broken; The stripe data of this
7426                  * disk is lost.
7427                  *
7428                  * We only allow DISCARD if the sysadmin has confirmed that
7429                  * only safe devices are in use by setting a module parameter.
7430                  * A better idea might be to turn DISCARD into WRITE_ZEROES
7431                  * requests, as that is required to be safe.
7432                  */
7433                 if (devices_handle_discard_safely &&
7434                     mddev->queue->limits.max_discard_sectors >= (stripe >> 9) &&
7435                     mddev->queue->limits.discard_granularity >= stripe)
7436                         queue_flag_set_unlocked(QUEUE_FLAG_DISCARD,
7437                                                 mddev->queue);
7438                 else
7439                         queue_flag_clear_unlocked(QUEUE_FLAG_DISCARD,
7440                                                 mddev->queue);
7441
7442                 blk_queue_max_hw_sectors(mddev->queue, UINT_MAX);
7443         }
7444
7445         if (log_init(conf, journal_dev, raid5_has_ppl(conf)))
7446                 goto abort;
7447
7448         return 0;
7449 abort:
7450         md_unregister_thread(&mddev->thread);
7451         print_raid5_conf(conf);
7452         free_conf(conf);
7453         mddev->private = NULL;
7454         pr_warn("md/raid:%s: failed to run raid set.\n", mdname(mddev));
7455         return -EIO;
7456 }
7457
7458 static void raid5_free(struct mddev *mddev, void *priv)
7459 {
7460         struct r5conf *conf = priv;
7461
7462         free_conf(conf);
7463         mddev->to_remove = &raid5_attrs_group;
7464 }
7465
7466 static void raid5_status(struct seq_file *seq, struct mddev *mddev)
7467 {
7468         struct r5conf *conf = mddev->private;
7469         int i;
7470
7471         seq_printf(seq, " level %d, %dk chunk, algorithm %d", mddev->level,
7472                 conf->chunk_sectors / 2, mddev->layout);
7473         seq_printf (seq, " [%d/%d] [", conf->raid_disks, conf->raid_disks - mddev->degraded);
7474         rcu_read_lock();
7475         for (i = 0; i < conf->raid_disks; i++) {
7476                 struct md_rdev *rdev = rcu_dereference(conf->disks[i].rdev);
7477                 seq_printf (seq, "%s", rdev && test_bit(In_sync, &rdev->flags) ? "U" : "_");
7478         }
7479         rcu_read_unlock();
7480         seq_printf (seq, "]");
7481 }
7482
7483 static void print_raid5_conf (struct r5conf *conf)
7484 {
7485         int i;
7486         struct disk_info *tmp;
7487
7488         pr_debug("RAID conf printout:\n");
7489         if (!conf) {
7490                 pr_debug("(conf==NULL)\n");
7491                 return;
7492         }
7493         pr_debug(" --- level:%d rd:%d wd:%d\n", conf->level,
7494                conf->raid_disks,
7495                conf->raid_disks - conf->mddev->degraded);
7496
7497         for (i = 0; i < conf->raid_disks; i++) {
7498                 char b[BDEVNAME_SIZE];
7499                 tmp = conf->disks + i;
7500                 if (tmp->rdev)
7501                         pr_debug(" disk %d, o:%d, dev:%s\n",
7502                                i, !test_bit(Faulty, &tmp->rdev->flags),
7503                                bdevname(tmp->rdev->bdev, b));
7504         }
7505 }
7506
7507 static int raid5_spare_active(struct mddev *mddev)
7508 {
7509         int i;
7510         struct r5conf *conf = mddev->private;
7511         struct disk_info *tmp;
7512         int count = 0;
7513         unsigned long flags;
7514
7515         for (i = 0; i < conf->raid_disks; i++) {
7516                 tmp = conf->disks + i;
7517                 if (tmp->replacement
7518                     && tmp->replacement->recovery_offset == MaxSector
7519                     && !test_bit(Faulty, &tmp->replacement->flags)
7520                     && !test_and_set_bit(In_sync, &tmp->replacement->flags)) {
7521                         /* Replacement has just become active. */
7522                         if (!tmp->rdev
7523                             || !test_and_clear_bit(In_sync, &tmp->rdev->flags))
7524                                 count++;
7525                         if (tmp->rdev) {
7526                                 /* Replaced device not technically faulty,
7527                                  * but we need to be sure it gets removed
7528                                  * and never re-added.
7529                                  */
7530                                 set_bit(Faulty, &tmp->rdev->flags);
7531                                 sysfs_notify_dirent_safe(
7532                                         tmp->rdev->sysfs_state);
7533                         }
7534                         sysfs_notify_dirent_safe(tmp->replacement->sysfs_state);
7535                 } else if (tmp->rdev
7536                     && tmp->rdev->recovery_offset == MaxSector
7537                     && !test_bit(Faulty, &tmp->rdev->flags)
7538                     && !test_and_set_bit(In_sync, &tmp->rdev->flags)) {
7539                         count++;
7540                         sysfs_notify_dirent_safe(tmp->rdev->sysfs_state);
7541                 }
7542         }
7543         spin_lock_irqsave(&conf->device_lock, flags);
7544         mddev->degraded = raid5_calc_degraded(conf);
7545         spin_unlock_irqrestore(&conf->device_lock, flags);
7546         print_raid5_conf(conf);
7547         return count;
7548 }
7549
7550 static int raid5_remove_disk(struct mddev *mddev, struct md_rdev *rdev)
7551 {
7552         struct r5conf *conf = mddev->private;
7553         int err = 0;
7554         int number = rdev->raid_disk;
7555         struct md_rdev **rdevp;
7556         struct disk_info *p = conf->disks + number;
7557
7558         print_raid5_conf(conf);
7559         if (test_bit(Journal, &rdev->flags) && conf->log) {
7560                 /*
7561                  * we can't wait pending write here, as this is called in
7562                  * raid5d, wait will deadlock.
7563                  * neilb: there is no locking about new writes here,
7564                  * so this cannot be safe.
7565                  */
7566                 if (atomic_read(&conf->active_stripes) ||
7567                     atomic_read(&conf->r5c_cached_full_stripes) ||
7568                     atomic_read(&conf->r5c_cached_partial_stripes)) {
7569                         return -EBUSY;
7570                 }
7571                 log_exit(conf);
7572                 return 0;
7573         }
7574         if (rdev == p->rdev)
7575                 rdevp = &p->rdev;
7576         else if (rdev == p->replacement)
7577                 rdevp = &p->replacement;
7578         else
7579                 return 0;
7580
7581         if (number >= conf->raid_disks &&
7582             conf->reshape_progress == MaxSector)
7583                 clear_bit(In_sync, &rdev->flags);
7584
7585         if (test_bit(In_sync, &rdev->flags) ||
7586             atomic_read(&rdev->nr_pending)) {
7587                 err = -EBUSY;
7588                 goto abort;
7589         }
7590         /* Only remove non-faulty devices if recovery
7591          * isn't possible.
7592          */
7593         if (!test_bit(Faulty, &rdev->flags) &&
7594             mddev->recovery_disabled != conf->recovery_disabled &&
7595             !has_failed(conf) &&
7596             (!p->replacement || p->replacement == rdev) &&
7597             number < conf->raid_disks) {
7598                 err = -EBUSY;
7599                 goto abort;
7600         }
7601         *rdevp = NULL;
7602         if (!test_bit(RemoveSynchronized, &rdev->flags)) {
7603                 synchronize_rcu();
7604                 if (atomic_read(&rdev->nr_pending)) {
7605                         /* lost the race, try later */
7606                         err = -EBUSY;
7607                         *rdevp = rdev;
7608                 }
7609         }
7610         if (!err) {
7611                 err = log_modify(conf, rdev, false);
7612                 if (err)
7613                         goto abort;
7614         }
7615         if (p->replacement) {
7616                 /* We must have just cleared 'rdev' */
7617                 p->rdev = p->replacement;
7618                 clear_bit(Replacement, &p->replacement->flags);
7619                 smp_mb(); /* Make sure other CPUs may see both as identical
7620                            * but will never see neither - if they are careful
7621                            */
7622                 p->replacement = NULL;
7623
7624                 if (!err)
7625                         err = log_modify(conf, p->rdev, true);
7626         }
7627
7628         clear_bit(WantReplacement, &rdev->flags);
7629 abort:
7630
7631         print_raid5_conf(conf);
7632         return err;
7633 }
7634
7635 static int raid5_add_disk(struct mddev *mddev, struct md_rdev *rdev)
7636 {
7637         struct r5conf *conf = mddev->private;
7638         int err = -EEXIST;
7639         int disk;
7640         struct disk_info *p;
7641         int first = 0;
7642         int last = conf->raid_disks - 1;
7643
7644         if (test_bit(Journal, &rdev->flags)) {
7645                 if (conf->log)
7646                         return -EBUSY;
7647
7648                 rdev->raid_disk = 0;
7649                 /*
7650                  * The array is in readonly mode if journal is missing, so no
7651                  * write requests running. We should be safe
7652                  */
7653                 log_init(conf, rdev, false);
7654                 return 0;
7655         }
7656         if (mddev->recovery_disabled == conf->recovery_disabled)
7657                 return -EBUSY;
7658
7659         if (rdev->saved_raid_disk < 0 && has_failed(conf))
7660                 /* no point adding a device */
7661                 return -EINVAL;
7662
7663         if (rdev->raid_disk >= 0)
7664                 first = last = rdev->raid_disk;
7665
7666         /*
7667          * find the disk ... but prefer rdev->saved_raid_disk
7668          * if possible.
7669          */
7670         if (rdev->saved_raid_disk >= 0 &&
7671             rdev->saved_raid_disk >= first &&
7672             conf->disks[rdev->saved_raid_disk].rdev == NULL)
7673                 first = rdev->saved_raid_disk;
7674
7675         for (disk = first; disk <= last; disk++) {
7676                 p = conf->disks + disk;
7677                 if (p->rdev == NULL) {
7678                         clear_bit(In_sync, &rdev->flags);
7679                         rdev->raid_disk = disk;
7680                         if (rdev->saved_raid_disk != disk)
7681                                 conf->fullsync = 1;
7682                         rcu_assign_pointer(p->rdev, rdev);
7683
7684                         err = log_modify(conf, rdev, true);
7685
7686                         goto out;
7687                 }
7688         }
7689         for (disk = first; disk <= last; disk++) {
7690                 p = conf->disks + disk;
7691                 if (test_bit(WantReplacement, &p->rdev->flags) &&
7692                     p->replacement == NULL) {
7693                         clear_bit(In_sync, &rdev->flags);
7694                         set_bit(Replacement, &rdev->flags);
7695                         rdev->raid_disk = disk;
7696                         err = 0;
7697                         conf->fullsync = 1;
7698                         rcu_assign_pointer(p->replacement, rdev);
7699                         break;
7700                 }
7701         }
7702 out:
7703         print_raid5_conf(conf);
7704         return err;
7705 }
7706
7707 static int raid5_resize(struct mddev *mddev, sector_t sectors)
7708 {
7709         /* no resync is happening, and there is enough space
7710          * on all devices, so we can resize.
7711          * We need to make sure resync covers any new space.
7712          * If the array is shrinking we should possibly wait until
7713          * any io in the removed space completes, but it hardly seems
7714          * worth it.
7715          */
7716         sector_t newsize;
7717         struct r5conf *conf = mddev->private;
7718
7719         if (conf->log || raid5_has_ppl(conf))
7720                 return -EINVAL;
7721         sectors &= ~((sector_t)conf->chunk_sectors - 1);
7722         newsize = raid5_size(mddev, sectors, mddev->raid_disks);
7723         if (mddev->external_size &&
7724             mddev->array_sectors > newsize)
7725                 return -EINVAL;
7726         if (mddev->bitmap) {
7727                 int ret = bitmap_resize(mddev->bitmap, sectors, 0, 0);
7728                 if (ret)
7729                         return ret;
7730         }
7731         md_set_array_sectors(mddev, newsize);
7732         if (sectors > mddev->dev_sectors &&
7733             mddev->recovery_cp > mddev->dev_sectors) {
7734                 mddev->recovery_cp = mddev->dev_sectors;
7735                 set_bit(MD_RECOVERY_NEEDED, &mddev->recovery);
7736         }
7737         mddev->dev_sectors = sectors;
7738         mddev->resync_max_sectors = sectors;
7739         return 0;
7740 }
7741
7742 static int check_stripe_cache(struct mddev *mddev)
7743 {
7744         /* Can only proceed if there are plenty of stripe_heads.
7745          * We need a minimum of one full stripe,, and for sensible progress
7746          * it is best to have about 4 times that.
7747          * If we require 4 times, then the default 256 4K stripe_heads will
7748          * allow for chunk sizes up to 256K, which is probably OK.
7749          * If the chunk size is greater, user-space should request more
7750          * stripe_heads first.
7751          */
7752         struct r5conf *conf = mddev->private;
7753         if (((mddev->chunk_sectors << 9) / STRIPE_SIZE) * 4
7754             > conf->min_nr_stripes ||
7755             ((mddev->new_chunk_sectors << 9) / STRIPE_SIZE) * 4
7756             > conf->min_nr_stripes) {
7757                 pr_warn("md/raid:%s: reshape: not enough stripes.  Needed %lu\n",
7758                         mdname(mddev),
7759                         ((max(mddev->chunk_sectors, mddev->new_chunk_sectors) << 9)
7760                          / STRIPE_SIZE)*4);
7761                 return 0;
7762         }
7763         return 1;
7764 }
7765
7766 static int check_reshape(struct mddev *mddev)
7767 {
7768         struct r5conf *conf = mddev->private;
7769
7770         if (conf->log || raid5_has_ppl(conf))
7771                 return -EINVAL;
7772         if (mddev->delta_disks == 0 &&
7773             mddev->new_layout == mddev->layout &&
7774             mddev->new_chunk_sectors == mddev->chunk_sectors)
7775                 return 0; /* nothing to do */
7776         if (has_failed(conf))
7777                 return -EINVAL;
7778         if (mddev->delta_disks < 0 && mddev->reshape_position == MaxSector) {
7779                 /* We might be able to shrink, but the devices must
7780                  * be made bigger first.
7781                  * For raid6, 4 is the minimum size.
7782                  * Otherwise 2 is the minimum
7783                  */
7784                 int min = 2;
7785                 if (mddev->level == 6)
7786                         min = 4;
7787                 if (mddev->raid_disks + mddev->delta_disks < min)
7788                         return -EINVAL;
7789         }
7790
7791         if (!check_stripe_cache(mddev))
7792                 return -ENOSPC;
7793
7794         if (mddev->new_chunk_sectors > mddev->chunk_sectors ||
7795             mddev->delta_disks > 0)
7796                 if (resize_chunks(conf,
7797                                   conf->previous_raid_disks
7798                                   + max(0, mddev->delta_disks),
7799                                   max(mddev->new_chunk_sectors,
7800                                       mddev->chunk_sectors)
7801                             ) < 0)
7802                         return -ENOMEM;
7803
7804         if (conf->previous_raid_disks + mddev->delta_disks <= conf->pool_size)
7805                 return 0; /* never bother to shrink */
7806         return resize_stripes(conf, (conf->previous_raid_disks
7807                                      + mddev->delta_disks));
7808 }
7809
7810 static int raid5_start_reshape(struct mddev *mddev)
7811 {
7812         struct r5conf *conf = mddev->private;
7813         struct md_rdev *rdev;
7814         int spares = 0;
7815         unsigned long flags;
7816
7817         if (test_bit(MD_RECOVERY_RUNNING, &mddev->recovery))
7818                 return -EBUSY;
7819
7820         if (!check_stripe_cache(mddev))
7821                 return -ENOSPC;
7822
7823         if (has_failed(conf))
7824                 return -EINVAL;
7825
7826         rdev_for_each(rdev, mddev) {
7827                 if (!test_bit(In_sync, &rdev->flags)
7828                     && !test_bit(Faulty, &rdev->flags))
7829                         spares++;
7830         }
7831
7832         if (spares - mddev->degraded < mddev->delta_disks - conf->max_degraded)
7833                 /* Not enough devices even to make a degraded array
7834                  * of that size
7835                  */
7836                 return -EINVAL;
7837
7838         /* Refuse to reduce size of the array.  Any reductions in
7839          * array size must be through explicit setting of array_size
7840          * attribute.
7841          */
7842         if (raid5_size(mddev, 0, conf->raid_disks + mddev->delta_disks)
7843             < mddev->array_sectors) {
7844                 pr_warn("md/raid:%s: array size must be reduced before number of disks\n",
7845                         mdname(mddev));
7846                 return -EINVAL;
7847         }
7848
7849         atomic_set(&conf->reshape_stripes, 0);
7850         spin_lock_irq(&conf->device_lock);
7851         write_seqcount_begin(&conf->gen_lock);
7852         conf->previous_raid_disks = conf->raid_disks;
7853         conf->raid_disks += mddev->delta_disks;
7854         conf->prev_chunk_sectors = conf->chunk_sectors;
7855         conf->chunk_sectors = mddev->new_chunk_sectors;
7856         conf->prev_algo = conf->algorithm;
7857         conf->algorithm = mddev->new_layout;
7858         conf->generation++;
7859         /* Code that selects data_offset needs to see the generation update
7860          * if reshape_progress has been set - so a memory barrier needed.
7861          */
7862         smp_mb();
7863         if (mddev->reshape_backwards)
7864                 conf->reshape_progress = raid5_size(mddev, 0, 0);
7865         else
7866                 conf->reshape_progress = 0;
7867         conf->reshape_safe = conf->reshape_progress;
7868         write_seqcount_end(&conf->gen_lock);
7869         spin_unlock_irq(&conf->device_lock);
7870
7871         /* Now make sure any requests that proceeded on the assumption
7872          * the reshape wasn't running - like Discard or Read - have
7873          * completed.
7874          */
7875         mddev_suspend(mddev);
7876         mddev_resume(mddev);
7877
7878         /* Add some new drives, as many as will fit.
7879          * We know there are enough to make the newly sized array work.
7880          * Don't add devices if we are reducing the number of
7881          * devices in the array.  This is because it is not possible
7882          * to correctly record the "partially reconstructed" state of
7883          * such devices during the reshape and confusion could result.
7884          */
7885         if (mddev->delta_disks >= 0) {
7886                 rdev_for_each(rdev, mddev)
7887                         if (rdev->raid_disk < 0 &&
7888                             !test_bit(Faulty, &rdev->flags)) {
7889                                 if (raid5_add_disk(mddev, rdev) == 0) {
7890                                         if (rdev->raid_disk
7891                                             >= conf->previous_raid_disks)
7892                                                 set_bit(In_sync, &rdev->flags);
7893                                         else
7894                                                 rdev->recovery_offset = 0;
7895
7896                                         if (sysfs_link_rdev(mddev, rdev))
7897                                                 /* Failure here is OK */;
7898                                 }
7899                         } else if (rdev->raid_disk >= conf->previous_raid_disks
7900                                    && !test_bit(Faulty, &rdev->flags)) {
7901                                 /* This is a spare that was manually added */
7902                                 set_bit(In_sync, &rdev->flags);
7903                         }
7904
7905                 /* When a reshape changes the number of devices,
7906                  * ->degraded is measured against the larger of the
7907                  * pre and post number of devices.
7908                  */
7909                 spin_lock_irqsave(&conf->device_lock, flags);
7910                 mddev->degraded = raid5_calc_degraded(conf);
7911                 spin_unlock_irqrestore(&conf->device_lock, flags);
7912         }
7913         mddev->raid_disks = conf->raid_disks;
7914         mddev->reshape_position = conf->reshape_progress;
7915         set_bit(MD_SB_CHANGE_DEVS, &mddev->sb_flags);
7916
7917         clear_bit(MD_RECOVERY_SYNC, &mddev->recovery);
7918         clear_bit(MD_RECOVERY_CHECK, &mddev->recovery);
7919         clear_bit(MD_RECOVERY_DONE, &mddev->recovery);
7920         set_bit(MD_RECOVERY_RESHAPE, &mddev->recovery);
7921         set_bit(MD_RECOVERY_RUNNING, &mddev->recovery);
7922         mddev->sync_thread = md_register_thread(md_do_sync, mddev,
7923                                                 "reshape");
7924         if (!mddev->sync_thread) {
7925                 mddev->recovery = 0;
7926                 spin_lock_irq(&conf->device_lock);
7927                 write_seqcount_begin(&conf->gen_lock);
7928                 mddev->raid_disks = conf->raid_disks = conf->previous_raid_disks;
7929                 mddev->new_chunk_sectors =
7930                         conf->chunk_sectors = conf->prev_chunk_sectors;
7931                 mddev->new_layout = conf->algorithm = conf->prev_algo;
7932                 rdev_for_each(rdev, mddev)
7933                         rdev->new_data_offset = rdev->data_offset;
7934                 smp_wmb();
7935                 conf->generation --;
7936                 conf->reshape_progress = MaxSector;
7937                 mddev->reshape_position = MaxSector;
7938                 write_seqcount_end(&conf->gen_lock);
7939                 spin_unlock_irq(&conf->device_lock);
7940                 return -EAGAIN;
7941         }
7942         conf->reshape_checkpoint = jiffies;
7943         md_wakeup_thread(mddev->sync_thread);
7944         md_new_event(mddev);
7945         return 0;
7946 }
7947
7948 /* This is called from the reshape thread and should make any
7949  * changes needed in 'conf'
7950  */
7951 static void end_reshape(struct r5conf *conf)
7952 {
7953
7954         if (!test_bit(MD_RECOVERY_INTR, &conf->mddev->recovery)) {
7955
7956                 spin_lock_irq(&conf->device_lock);
7957                 conf->previous_raid_disks = conf->raid_disks;
7958                 md_finish_reshape(conf->mddev);
7959                 smp_wmb();
7960                 conf->reshape_progress = MaxSector;
7961                 conf->mddev->reshape_position = MaxSector;
7962                 spin_unlock_irq(&conf->device_lock);
7963                 wake_up(&conf->wait_for_overlap);
7964
7965                 /* read-ahead size must cover two whole stripes, which is
7966                  * 2 * (datadisks) * chunksize where 'n' is the number of raid devices
7967                  */
7968                 if (conf->mddev->queue) {
7969                         int data_disks = conf->raid_disks - conf->max_degraded;
7970                         int stripe = data_disks * ((conf->chunk_sectors << 9)
7971                                                    / PAGE_SIZE);
7972                         if (conf->mddev->queue->backing_dev_info->ra_pages < 2 * stripe)
7973                                 conf->mddev->queue->backing_dev_info->ra_pages = 2 * stripe;
7974                 }
7975         }
7976 }
7977
7978 /* This is called from the raid5d thread with mddev_lock held.
7979  * It makes config changes to the device.
7980  */
7981 static void raid5_finish_reshape(struct mddev *mddev)
7982 {
7983         struct r5conf *conf = mddev->private;
7984
7985         if (!test_bit(MD_RECOVERY_INTR, &mddev->recovery)) {
7986
7987                 if (mddev->delta_disks > 0) {
7988                         md_set_array_sectors(mddev, raid5_size(mddev, 0, 0));
7989                         if (mddev->queue) {
7990                                 set_capacity(mddev->gendisk, mddev->array_sectors);
7991                                 revalidate_disk(mddev->gendisk);
7992                         }
7993                 } else {
7994                         int d;
7995                         spin_lock_irq(&conf->device_lock);
7996                         mddev->degraded = raid5_calc_degraded(conf);
7997                         spin_unlock_irq(&conf->device_lock);
7998                         for (d = conf->raid_disks ;
7999                              d < conf->raid_disks - mddev->delta_disks;
8000                              d++) {
8001                                 struct md_rdev *rdev = conf->disks[d].rdev;
8002                                 if (rdev)
8003                                         clear_bit(In_sync, &rdev->flags);
8004                                 rdev = conf->disks[d].replacement;
8005                                 if (rdev)
8006                                         clear_bit(In_sync, &rdev->flags);
8007                         }
8008                 }
8009                 mddev->layout = conf->algorithm;
8010                 mddev->chunk_sectors = conf->chunk_sectors;
8011                 mddev->reshape_position = MaxSector;
8012                 mddev->delta_disks = 0;
8013                 mddev->reshape_backwards = 0;
8014         }
8015 }
8016
8017 static void raid5_quiesce(struct mddev *mddev, int state)
8018 {
8019         struct r5conf *conf = mddev->private;
8020
8021         switch(state) {
8022         case 2: /* resume for a suspend */
8023                 wake_up(&conf->wait_for_overlap);
8024                 break;
8025
8026         case 1: /* stop all writes */
8027                 lock_all_device_hash_locks_irq(conf);
8028                 /* '2' tells resync/reshape to pause so that all
8029                  * active stripes can drain
8030                  */
8031                 r5c_flush_cache(conf, INT_MAX);
8032                 conf->quiesce = 2;
8033                 wait_event_cmd(conf->wait_for_quiescent,
8034                                     atomic_read(&conf->active_stripes) == 0 &&
8035                                     atomic_read(&conf->active_aligned_reads) == 0,
8036                                     unlock_all_device_hash_locks_irq(conf),
8037                                     lock_all_device_hash_locks_irq(conf));
8038                 conf->quiesce = 1;
8039                 unlock_all_device_hash_locks_irq(conf);
8040                 /* allow reshape to continue */
8041                 wake_up(&conf->wait_for_overlap);
8042                 break;
8043
8044         case 0: /* re-enable writes */
8045                 lock_all_device_hash_locks_irq(conf);
8046                 conf->quiesce = 0;
8047                 wake_up(&conf->wait_for_quiescent);
8048                 wake_up(&conf->wait_for_overlap);
8049                 unlock_all_device_hash_locks_irq(conf);
8050                 break;
8051         }
8052         r5l_quiesce(conf->log, state);
8053 }
8054
8055 static void *raid45_takeover_raid0(struct mddev *mddev, int level)
8056 {
8057         struct r0conf *raid0_conf = mddev->private;
8058         sector_t sectors;
8059
8060         /* for raid0 takeover only one zone is supported */
8061         if (raid0_conf->nr_strip_zones > 1) {
8062                 pr_warn("md/raid:%s: cannot takeover raid0 with more than one zone.\n",
8063                         mdname(mddev));
8064                 return ERR_PTR(-EINVAL);
8065         }
8066
8067         sectors = raid0_conf->strip_zone[0].zone_end;
8068         sector_div(sectors, raid0_conf->strip_zone[0].nb_dev);
8069         mddev->dev_sectors = sectors;
8070         mddev->new_level = level;
8071         mddev->new_layout = ALGORITHM_PARITY_N;
8072         mddev->new_chunk_sectors = mddev->chunk_sectors;
8073         mddev->raid_disks += 1;
8074         mddev->delta_disks = 1;
8075         /* make sure it will be not marked as dirty */
8076         mddev->recovery_cp = MaxSector;
8077
8078         return setup_conf(mddev);
8079 }
8080
8081 static void *raid5_takeover_raid1(struct mddev *mddev)
8082 {
8083         int chunksect;
8084         void *ret;
8085
8086         if (mddev->raid_disks != 2 ||
8087             mddev->degraded > 1)
8088                 return ERR_PTR(-EINVAL);
8089
8090         /* Should check if there are write-behind devices? */
8091
8092         chunksect = 64*2; /* 64K by default */
8093
8094         /* The array must be an exact multiple of chunksize */
8095         while (chunksect && (mddev->array_sectors & (chunksect-1)))
8096                 chunksect >>= 1;
8097
8098         if ((chunksect<<9) < STRIPE_SIZE)
8099                 /* array size does not allow a suitable chunk size */
8100                 return ERR_PTR(-EINVAL);
8101
8102         mddev->new_level = 5;
8103         mddev->new_layout = ALGORITHM_LEFT_SYMMETRIC;
8104         mddev->new_chunk_sectors = chunksect;
8105
8106         ret = setup_conf(mddev);
8107         if (!IS_ERR(ret))
8108                 mddev_clear_unsupported_flags(mddev,
8109                         UNSUPPORTED_MDDEV_FLAGS);
8110         return ret;
8111 }
8112
8113 static void *raid5_takeover_raid6(struct mddev *mddev)
8114 {
8115         int new_layout;
8116
8117         switch (mddev->layout) {
8118         case ALGORITHM_LEFT_ASYMMETRIC_6:
8119                 new_layout = ALGORITHM_LEFT_ASYMMETRIC;
8120                 break;
8121         case ALGORITHM_RIGHT_ASYMMETRIC_6:
8122                 new_layout = ALGORITHM_RIGHT_ASYMMETRIC;
8123                 break;
8124         case ALGORITHM_LEFT_SYMMETRIC_6:
8125                 new_layout = ALGORITHM_LEFT_SYMMETRIC;
8126                 break;
8127         case ALGORITHM_RIGHT_SYMMETRIC_6:
8128                 new_layout = ALGORITHM_RIGHT_SYMMETRIC;
8129                 break;
8130         case ALGORITHM_PARITY_0_6:
8131                 new_layout = ALGORITHM_PARITY_0;
8132                 break;
8133         case ALGORITHM_PARITY_N:
8134                 new_layout = ALGORITHM_PARITY_N;
8135                 break;
8136         default:
8137                 return ERR_PTR(-EINVAL);
8138         }
8139         mddev->new_level = 5;
8140         mddev->new_layout = new_layout;
8141         mddev->delta_disks = -1;
8142         mddev->raid_disks -= 1;
8143         return setup_conf(mddev);
8144 }
8145
8146 static int raid5_check_reshape(struct mddev *mddev)
8147 {
8148         /* For a 2-drive array, the layout and chunk size can be changed
8149          * immediately as not restriping is needed.
8150          * For larger arrays we record the new value - after validation
8151          * to be used by a reshape pass.
8152          */
8153         struct r5conf *conf = mddev->private;
8154         int new_chunk = mddev->new_chunk_sectors;
8155
8156         if (mddev->new_layout >= 0 && !algorithm_valid_raid5(mddev->new_layout))
8157                 return -EINVAL;
8158         if (new_chunk > 0) {
8159                 if (!is_power_of_2(new_chunk))
8160                         return -EINVAL;
8161                 if (new_chunk < (PAGE_SIZE>>9))
8162                         return -EINVAL;
8163                 if (mddev->array_sectors & (new_chunk-1))
8164                         /* not factor of array size */
8165                         return -EINVAL;
8166         }
8167
8168         /* They look valid */
8169
8170         if (mddev->raid_disks == 2) {
8171                 /* can make the change immediately */
8172                 if (mddev->new_layout >= 0) {
8173                         conf->algorithm = mddev->new_layout;
8174                         mddev->layout = mddev->new_layout;
8175                 }
8176                 if (new_chunk > 0) {
8177                         conf->chunk_sectors = new_chunk ;
8178                         mddev->chunk_sectors = new_chunk;
8179                 }
8180                 set_bit(MD_SB_CHANGE_DEVS, &mddev->sb_flags);
8181                 md_wakeup_thread(mddev->thread);
8182         }
8183         return check_reshape(mddev);
8184 }
8185
8186 static int raid6_check_reshape(struct mddev *mddev)
8187 {
8188         int new_chunk = mddev->new_chunk_sectors;
8189
8190         if (mddev->new_layout >= 0 && !algorithm_valid_raid6(mddev->new_layout))
8191                 return -EINVAL;
8192         if (new_chunk > 0) {
8193                 if (!is_power_of_2(new_chunk))
8194                         return -EINVAL;
8195                 if (new_chunk < (PAGE_SIZE >> 9))
8196                         return -EINVAL;
8197                 if (mddev->array_sectors & (new_chunk-1))
8198                         /* not factor of array size */
8199                         return -EINVAL;
8200         }
8201
8202         /* They look valid */
8203         return check_reshape(mddev);
8204 }
8205
8206 static void *raid5_takeover(struct mddev *mddev)
8207 {
8208         /* raid5 can take over:
8209          *  raid0 - if there is only one strip zone - make it a raid4 layout
8210          *  raid1 - if there are two drives.  We need to know the chunk size
8211          *  raid4 - trivial - just use a raid4 layout.
8212          *  raid6 - Providing it is a *_6 layout
8213          */
8214         if (mddev->level == 0)
8215                 return raid45_takeover_raid0(mddev, 5);
8216         if (mddev->level == 1)
8217                 return raid5_takeover_raid1(mddev);
8218         if (mddev->level == 4) {
8219                 mddev->new_layout = ALGORITHM_PARITY_N;
8220                 mddev->new_level = 5;
8221                 return setup_conf(mddev);
8222         }
8223         if (mddev->level == 6)
8224                 return raid5_takeover_raid6(mddev);
8225
8226         return ERR_PTR(-EINVAL);
8227 }
8228
8229 static void *raid4_takeover(struct mddev *mddev)
8230 {
8231         /* raid4 can take over:
8232          *  raid0 - if there is only one strip zone
8233          *  raid5 - if layout is right
8234          */
8235         if (mddev->level == 0)
8236                 return raid45_takeover_raid0(mddev, 4);
8237         if (mddev->level == 5 &&
8238             mddev->layout == ALGORITHM_PARITY_N) {
8239                 mddev->new_layout = 0;
8240                 mddev->new_level = 4;
8241                 return setup_conf(mddev);
8242         }
8243         return ERR_PTR(-EINVAL);
8244 }
8245
8246 static struct md_personality raid5_personality;
8247
8248 static void *raid6_takeover(struct mddev *mddev)
8249 {
8250         /* Currently can only take over a raid5.  We map the
8251          * personality to an equivalent raid6 personality
8252          * with the Q block at the end.
8253          */
8254         int new_layout;
8255
8256         if (mddev->pers != &raid5_personality)
8257                 return ERR_PTR(-EINVAL);
8258         if (mddev->degraded > 1)
8259                 return ERR_PTR(-EINVAL);
8260         if (mddev->raid_disks > 253)
8261                 return ERR_PTR(-EINVAL);
8262         if (mddev->raid_disks < 3)
8263                 return ERR_PTR(-EINVAL);
8264
8265         switch (mddev->layout) {
8266         case ALGORITHM_LEFT_ASYMMETRIC:
8267                 new_layout = ALGORITHM_LEFT_ASYMMETRIC_6;
8268                 break;
8269         case ALGORITHM_RIGHT_ASYMMETRIC:
8270                 new_layout = ALGORITHM_RIGHT_ASYMMETRIC_6;
8271                 break;
8272         case ALGORITHM_LEFT_SYMMETRIC:
8273                 new_layout = ALGORITHM_LEFT_SYMMETRIC_6;
8274                 break;
8275         case ALGORITHM_RIGHT_SYMMETRIC:
8276                 new_layout = ALGORITHM_RIGHT_SYMMETRIC_6;
8277                 break;
8278         case ALGORITHM_PARITY_0:
8279                 new_layout = ALGORITHM_PARITY_0_6;
8280                 break;
8281         case ALGORITHM_PARITY_N:
8282                 new_layout = ALGORITHM_PARITY_N;
8283                 break;
8284         default:
8285                 return ERR_PTR(-EINVAL);
8286         }
8287         mddev->new_level = 6;
8288         mddev->new_layout = new_layout;
8289         mddev->delta_disks = 1;
8290         mddev->raid_disks += 1;
8291         return setup_conf(mddev);
8292 }
8293
8294 static int raid5_change_consistency_policy(struct mddev *mddev, const char *buf)
8295 {
8296         struct r5conf *conf;
8297         int err;
8298
8299         err = mddev_lock(mddev);
8300         if (err)
8301                 return err;
8302         conf = mddev->private;
8303         if (!conf) {
8304                 mddev_unlock(mddev);
8305                 return -ENODEV;
8306         }
8307
8308         if (strncmp(buf, "ppl", 3) == 0) {
8309                 /* ppl only works with RAID 5 */
8310                 if (!raid5_has_ppl(conf) && conf->level == 5) {
8311                         err = log_init(conf, NULL, true);
8312                         if (!err) {
8313                                 err = resize_stripes(conf, conf->pool_size);
8314                                 if (err)
8315                                         log_exit(conf);
8316                         }
8317                 } else
8318                         err = -EINVAL;
8319         } else if (strncmp(buf, "resync", 6) == 0) {
8320                 if (raid5_has_ppl(conf)) {
8321                         mddev_suspend(mddev);
8322                         log_exit(conf);
8323                         mddev_resume(mddev);
8324                         err = resize_stripes(conf, conf->pool_size);
8325                 } else if (test_bit(MD_HAS_JOURNAL, &conf->mddev->flags) &&
8326                            r5l_log_disk_error(conf)) {
8327                         bool journal_dev_exists = false;
8328                         struct md_rdev *rdev;
8329
8330                         rdev_for_each(rdev, mddev)
8331                                 if (test_bit(Journal, &rdev->flags)) {
8332                                         journal_dev_exists = true;
8333                                         break;
8334                                 }
8335
8336                         if (!journal_dev_exists) {
8337                                 mddev_suspend(mddev);
8338                                 clear_bit(MD_HAS_JOURNAL, &mddev->flags);
8339                                 mddev_resume(mddev);
8340                         } else  /* need remove journal device first */
8341                                 err = -EBUSY;
8342                 } else
8343                         err = -EINVAL;
8344         } else {
8345                 err = -EINVAL;
8346         }
8347
8348         if (!err)
8349                 md_update_sb(mddev, 1);
8350
8351         mddev_unlock(mddev);
8352
8353         return err;
8354 }
8355
8356 static struct md_personality raid6_personality =
8357 {
8358         .name           = "raid6",
8359         .level          = 6,
8360         .owner          = THIS_MODULE,
8361         .make_request   = raid5_make_request,
8362         .run            = raid5_run,
8363         .free           = raid5_free,
8364         .status         = raid5_status,
8365         .error_handler  = raid5_error,
8366         .hot_add_disk   = raid5_add_disk,
8367         .hot_remove_disk= raid5_remove_disk,
8368         .spare_active   = raid5_spare_active,
8369         .sync_request   = raid5_sync_request,
8370         .resize         = raid5_resize,
8371         .size           = raid5_size,
8372         .check_reshape  = raid6_check_reshape,
8373         .start_reshape  = raid5_start_reshape,
8374         .finish_reshape = raid5_finish_reshape,
8375         .quiesce        = raid5_quiesce,
8376         .takeover       = raid6_takeover,
8377         .congested      = raid5_congested,
8378         .change_consistency_policy = raid5_change_consistency_policy,
8379 };
8380 static struct md_personality raid5_personality =
8381 {
8382         .name           = "raid5",
8383         .level          = 5,
8384         .owner          = THIS_MODULE,
8385         .make_request   = raid5_make_request,
8386         .run            = raid5_run,
8387         .free           = raid5_free,
8388         .status         = raid5_status,
8389         .error_handler  = raid5_error,
8390         .hot_add_disk   = raid5_add_disk,
8391         .hot_remove_disk= raid5_remove_disk,
8392         .spare_active   = raid5_spare_active,
8393         .sync_request   = raid5_sync_request,
8394         .resize         = raid5_resize,
8395         .size           = raid5_size,
8396         .check_reshape  = raid5_check_reshape,
8397         .start_reshape  = raid5_start_reshape,
8398         .finish_reshape = raid5_finish_reshape,
8399         .quiesce        = raid5_quiesce,
8400         .takeover       = raid5_takeover,
8401         .congested      = raid5_congested,
8402         .change_consistency_policy = raid5_change_consistency_policy,
8403 };
8404
8405 static struct md_personality raid4_personality =
8406 {
8407         .name           = "raid4",
8408         .level          = 4,
8409         .owner          = THIS_MODULE,
8410         .make_request   = raid5_make_request,
8411         .run            = raid5_run,
8412         .free           = raid5_free,
8413         .status         = raid5_status,
8414         .error_handler  = raid5_error,
8415         .hot_add_disk   = raid5_add_disk,
8416         .hot_remove_disk= raid5_remove_disk,
8417         .spare_active   = raid5_spare_active,
8418         .sync_request   = raid5_sync_request,
8419         .resize         = raid5_resize,
8420         .size           = raid5_size,
8421         .check_reshape  = raid5_check_reshape,
8422         .start_reshape  = raid5_start_reshape,
8423         .finish_reshape = raid5_finish_reshape,
8424         .quiesce        = raid5_quiesce,
8425         .takeover       = raid4_takeover,
8426         .congested      = raid5_congested,
8427         .change_consistency_policy = raid5_change_consistency_policy,
8428 };
8429
8430 static int __init raid5_init(void)
8431 {
8432         int ret;
8433
8434         raid5_wq = alloc_workqueue("raid5wq",
8435                 WQ_UNBOUND|WQ_MEM_RECLAIM|WQ_CPU_INTENSIVE|WQ_SYSFS, 0);
8436         if (!raid5_wq)
8437                 return -ENOMEM;
8438
8439         ret = cpuhp_setup_state_multi(CPUHP_MD_RAID5_PREPARE,
8440                                       "md/raid5:prepare",
8441                                       raid456_cpu_up_prepare,
8442                                       raid456_cpu_dead);
8443         if (ret) {
8444                 destroy_workqueue(raid5_wq);
8445                 return ret;
8446         }
8447         register_md_personality(&raid6_personality);
8448         register_md_personality(&raid5_personality);
8449         register_md_personality(&raid4_personality);
8450         return 0;
8451 }
8452
8453 static void raid5_exit(void)
8454 {
8455         unregister_md_personality(&raid6_personality);
8456         unregister_md_personality(&raid5_personality);
8457         unregister_md_personality(&raid4_personality);
8458         cpuhp_remove_multi_state(CPUHP_MD_RAID5_PREPARE);
8459         destroy_workqueue(raid5_wq);
8460 }
8461
8462 module_init(raid5_init);
8463 module_exit(raid5_exit);
8464 MODULE_LICENSE("GPL");
8465 MODULE_DESCRIPTION("RAID4/5/6 (striping with parity) personality for MD");
8466 MODULE_ALIAS("md-personality-4"); /* RAID5 */
8467 MODULE_ALIAS("md-raid5");
8468 MODULE_ALIAS("md-raid4");
8469 MODULE_ALIAS("md-level-5");
8470 MODULE_ALIAS("md-level-4");
8471 MODULE_ALIAS("md-personality-8"); /* RAID6 */
8472 MODULE_ALIAS("md-raid6");
8473 MODULE_ALIAS("md-level-6");
8474
8475 /* This used to be two separate modules, they were: */
8476 MODULE_ALIAS("raid5");
8477 MODULE_ALIAS("raid6");