sys/vfs/hammer2/hammer2_flush.c

   1 /*
   2  * Copyright (c) 2011-2013 The DragonFly Project.  All rights reserved.
   3  *
   4  * This code is derived from software contributed to The DragonFly Project
   5  * by Matthew Dillon <dillon@dragonflybsd.org>
   6  * by Venkatesh Srinivas <vsrinivas@dragonflybsd.org>
   7  *
   8  * Redistribution and use in source and binary forms, with or without
   9  * modification, are permitted provided that the following conditions
  10  * are met:
  11  *
  12  * 1. Redistributions of source code must retain the above copyright
  13  *    notice, this list of conditions and the following disclaimer.
  14  * 2. Redistributions in binary form must reproduce the above copyright
  15  *    notice, this list of conditions and the following disclaimer in
  16  *    the documentation and/or other materials provided with the
  17  *    distribution.
  18  * 3. Neither the name of The DragonFly Project nor the names of its
  19  *    contributors may be used to endorse or promote products derived
  20  *    from this software without specific, prior written permission.
  21  *
  22  * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
  23  * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
  24  * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
  25  * FOR A PARTICULAR PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE
  26  * COPYRIGHT HOLDERS OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
  27  * INCIDENTAL, SPECIAL, EXEMPLARY OR CONSEQUENTIAL DAMAGES (INCLUDING,
  28  * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
  29  * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
  30  * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
  31  * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
  32  * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  33  * SUCH DAMAGE.
  34  */
  35
  36 #include <sys/cdefs.h>
  37 #include <sys/param.h>
  38 #include <sys/systm.h>
  39 #include <sys/types.h>
  40 #include <sys/lock.h>
  41 #include <sys/uuid.h>
  42
  43 #include "hammer2.h"
  44
  45 /*
  46  * Recursively flush the specified chain.  The chain is locked and
  47  * referenced by the caller and will remain so on return.  The chain
  48  * will remain referenced throughout but can temporarily lose its
  49  * lock during the recursion to avoid unnecessarily stalling user
  50  * processes.
  51  */
  52 struct hammer2_flush_info {
  53         hammer2_chain_t *parent;
  54         hammer2_trans_t *trans;
  55         int             depth;
  56         int             diddeferral;
  57         int             pass;
  58         int             cache_index;
  59         struct h2_flush_deferral_list flush_list;
  60         hammer2_tid_t   sync_tid;       /* flush synchronization point */
  61         hammer2_tid_t   mirror_tid;     /* collect mirror TID updates */
  62 };
  63
  64 typedef struct hammer2_flush_info hammer2_flush_info_t;
  65
  66 static void hammer2_chain_flush_core(hammer2_flush_info_t *info,
  67                                 hammer2_chain_t *chain);
  68 static int hammer2_chain_flush_scan1(hammer2_chain_t *child, void *data);
  69 static int hammer2_chain_flush_scan2(hammer2_chain_t *child, void *data);
  70 static void hammer2_rollup_stats(hammer2_chain_t *parent,
  71                                 hammer2_chain_t *child, int how);
  72
  73 #if 0
  74 static __inline
  75 void
  76 hammer2_updatestats(hammer2_flush_info_t *info, hammer2_blockref_t *bref,
  77                     int how)
  78 {
  79         hammer2_key_t bytes;
  80
  81         if (bref->type != 0) {
  82                 bytes = 1 << (bref->data_off & HAMMER2_OFF_MASK_RADIX);
  83                 if (bref->type == HAMMER2_BREF_TYPE_INODE)
  84                         info->inode_count += how;
  85                 if (how < 0)
  86                         info->data_count -= bytes;
  87                 else
  88                         info->data_count += bytes;
  89         }
  90 }
  91 #endif
  92
  93 /*
  94  * Transaction support functions for writing to the filesystem.
  95  *
  96  * Initializing a new transaction allocates a transaction ID.  We
  97  * don't bother marking the volume header MODIFIED.  Instead, the volume
  98  * will be synchronized at a later time as part of a larger flush sequence.
  99  *
 100  * Non-flush transactions can typically run concurrently.  However if
 101  * there are non-flush transaction both before AND after a flush trans,
 102  * the transactions after stall until the ones before finish.
 103  *
 104  * Non-flush transactions occuring after a flush pointer can run concurrently
 105  * with that flush.  They only have to wait for transactions prior to the
 106  * flush trans to complete before they unstall.
 107  *
 108  * WARNING! Transaction ids are only allocated when the transaction becomes
 109  *          active, which allows other transactions to insert ahead of us
 110  *          if we are forced to block (only bioq transactions do that).
 111  *
 112  * WARNING! Modifications to the root volume cannot dup the root volume
 113  *          header to handle synchronization points, so alloc_tid can
 114  *          wind up (harmlessly) more advanced on flush.
 115  *
 116  * WARNING! Operations which might call inode_duplicate()/chain_duplicate()
 117  *          depend heavily on having a unique sync_tid to avoid duplication
 118  *          collisions (which key off of delete_tid).
 119  */
 120 void
 121 hammer2_trans_init(hammer2_trans_t *trans, hammer2_pfsmount_t *pmp, int flags)
 122 {
 123         hammer2_cluster_t *cluster;
 124         hammer2_mount_t *hmp;
 125         hammer2_trans_t *scan;
 126
 127         bzero(trans, sizeof(*trans));
 128         trans->pmp = pmp;
 129         cluster = pmp->cluster;
 130         hmp = cluster->hmp;
 131
 132         hammer2_voldata_lock(hmp);
 133         trans->flags = flags;
 134         trans->td = curthread;
 135         /*trans->delete_gen = 0;*/      /* multiple deletions within trans */
 136
 137         if (flags & HAMMER2_TRANS_ISFLUSH) {
 138                 /*
 139                  * If multiple flushes are trying to run we have to
 140                  * wait until it is our turn, then set curflush to
 141                  * indicate that a flush is now pending (but not
 142                  * necessarily active yet).
 143                  *
 144                  * NOTE: Do not set trans->blocked here.
 145                  */
 146                 ++hmp->flushcnt;
 147                 while (hmp->curflush != NULL) {
 148                         lksleep(&hmp->curflush, &hmp->voldatalk,
 149                                 0, "h2multf", hz);
 150                 }
 151                 hmp->curflush = trans;
 152                 TAILQ_INSERT_TAIL(&hmp->transq, trans, entry);
 153
 154                 /*
 155                  * If we are a flush we have to wait for all transactions
 156                  * prior to our flush synchronization point to complete
 157                  * before we can start our flush.
 158                  *
 159                  * Most importantly, this includes bioq flushes.
 160                  *
 161                  * NOTE: Do not set trans->blocked here.
 162                  */
 163                 while (TAILQ_FIRST(&hmp->transq) != trans) {
 164                         lksleep(&trans->sync_tid, &hmp->voldatalk,
 165                                 0, "h2syncw", hz);
 166                 }
 167
 168                 /*
 169                  * don't assign sync_tid until we become the running
 170                  * flush.  topo_flush_tid is used to control when
 171                  * chain modifications in concurrent transactions are
 172                  * required to delete-duplicate (so as not to disturb
 173                  * the state of what is being currently flushed).
 174                  */
 175                 trans->sync_tid = hmp->voldata.alloc_tid++;
 176                 hmp->topo_flush_tid = trans->sync_tid;
 177
 178                 /*
 179                  * Once we become the running flush we can wakeup anyone
 180                  * who blocked on us, up to the next flush.  That is,
 181                  * our flush can run concurrent with frontend operations.
 182                  */
 183                 scan = trans;
 184                 while ((scan = TAILQ_NEXT(scan, entry)) != NULL) {
 185                         if (scan->flags & HAMMER2_TRANS_ISFLUSH)
 186                                 break;
 187                         if (scan->blocked == 0)
 188                                 break;
 189                         scan->blocked = 0;
 190                         wakeup(&scan->blocked);
 191                 }
 192         } else if ((flags & HAMMER2_TRANS_BUFCACHE) && hmp->curflush) {
 193                 /*
 194                  * We cannot block if we are the bioq thread.  When a
 195                  * flush is not pending we can operate normally but
 196                  * if a flush IS pending the bioq thread's transaction
 197                  * must be placed either before or after curflush.
 198                  *
 199                  * If the current flush is waiting the bioq thread's
 200                  * transaction is placed before.  If it is running the
 201                  * bioq thread's transaction is placed after.
 202                  */
 203                 scan = TAILQ_FIRST(&hmp->transq);
 204                 if (scan != hmp->curflush) {
 205                         TAILQ_INSERT_BEFORE(hmp->curflush, trans, entry);
 206                 } else {
 207                         TAILQ_INSERT_TAIL(&hmp->transq, trans, entry);
 208                 }
 209                 trans->sync_tid = hmp->voldata.alloc_tid++;
 210         } else {
 211                 /*
 212                  * If this is a normal transaction and not a flush, or
 213                  * if this is a bioq transaction and no flush is pending,
 214                  * we can queue normally.
 215                  *
 216                  * Normal transactions must block while a pending flush is
 217                  * waiting for prior transactions to complete.  Once the
 218                  * pending flush becomes active we can run concurrently
 219                  * with it.
 220                  */
 221                 TAILQ_INSERT_TAIL(&hmp->transq, trans, entry);
 222                 scan = TAILQ_FIRST(&hmp->transq);
 223                 if (hmp->curflush && hmp->curflush != scan) {
 224                         trans->blocked = 1;
 225                         while (trans->blocked) {
 226                                 lksleep(&trans->blocked, &hmp->voldatalk,
 227                                         0, "h2trans", hz);
 228                         }
 229                 }
 230                 trans->sync_tid = hmp->voldata.alloc_tid++;
 231         }
 232         hammer2_voldata_unlock(hmp, 0);
 233 }
 234
 235 void
 236 hammer2_trans_done(hammer2_trans_t *trans)
 237 {
 238         hammer2_cluster_t *cluster;
 239         hammer2_mount_t *hmp;
 240         hammer2_trans_t *scan;
 241
 242         cluster = trans->pmp->cluster;
 243         hmp = cluster->hmp;
 244
 245         hammer2_voldata_lock(hmp);
 246         TAILQ_REMOVE(&hmp->transq, trans, entry);
 247         if (trans->flags & HAMMER2_TRANS_ISFLUSH) {
 248                 --hmp->flushcnt;
 249                 if (hmp->flushcnt) {
 250                         /*
 251                          * If we were a flush then wakeup anyone waiting on
 252                          * curflush (i.e. other flushes that want to run).
 253                          * Leave topo_flush_id set (I think we could probably
 254                          * clear it to zero here).
 255                          */
 256                         hmp->curflush = NULL;
 257                         wakeup(&hmp->curflush);
 258                 } else {
 259                         /*
 260                          * Theoretically we don't have to clear flush_tid
 261                          * here since the flush will have synchronized
 262                          * all operations <= flush_tid already.  But for
 263                          * now zero-it.
 264                          */
 265                         hmp->curflush = NULL;
 266                         hmp->topo_flush_tid = 0;
 267                 }
 268         } else {
 269                 /*
 270                  * If we are not a flush but a flush is now at the head
 271                  * of the queue and we were previously blocking it,
 272                  * we can now unblock it.
 273                  */
 274                 if (hmp->flushcnt &&
 275                     (scan = TAILQ_FIRST(&hmp->transq)) != NULL &&
 276                     trans->sync_tid < scan->sync_tid &&
 277                     (scan->flags & HAMMER2_TRANS_ISFLUSH)) {
 278                         wakeup(&scan->sync_tid);
 279                 }
 280         }
 281         hammer2_voldata_unlock(hmp, 0);
 282 }
 283
 284 /*
 285  * Flush the chain and all modified sub-chains through the specified
 286  * synchronization point (sync_tid), propagating parent chain modifications
 287  * and mirror_tid updates back up as needed.  Since we are recursing downward
 288  * we do not have to deal with the complexities of multi-homed chains (chains
 289  * with multiple parents).
 290  *
 291  * Caller must have interlocked against any non-flush-related modifying
 292  * operations in progress whos modify_tid values are less than or equal
 293  * to the passed sync_tid.
 294  *
 295  * Caller must have already vetted synchronization points to ensure they
 296  * are properly flushed.  Only snapshots and cluster flushes can create
 297  * these sorts of synchronization points.
 298  *
 299  * This routine can be called from several places but the most important
 300  * is from the hammer2_vop_reclaim() function.  We want to try to completely
 301  * clean out the inode structure to prevent disconnected inodes from
 302  * building up and blowing out the kmalloc pool.  However, it is not actually
 303  * necessary to flush reclaimed inodes to maintain HAMMER2's crash recovery
 304  * capability.
 305  *
 306  * chain is locked on call and will remain locked on return.  If a flush
 307  * occured, the chain's MOVED bit will be set indicating that its parent
 308  * (which is not part of the flush) should be updated.
 309  */
 310 void
 311 hammer2_chain_flush(hammer2_trans_t *trans, hammer2_chain_t *chain)
 312 {
 313         hammer2_chain_t *scan;
 314         hammer2_chain_core_t *core;
 315         hammer2_flush_info_t info;
 316
 317         /*
 318          * Execute the recursive flush and handle deferrals.
 319          *
 320          * Chains can be ridiculously long (thousands deep), so to
 321          * avoid blowing out the kernel stack the recursive flush has a
 322          * depth limit.  Elements at the limit are placed on a list
 323          * for re-execution after the stack has been popped.
 324          */
 325         bzero(&info, sizeof(info));
 326         TAILQ_INIT(&info.flush_list);
 327         info.trans = trans;
 328         info.sync_tid = trans->sync_tid;
 329         info.mirror_tid = 0;
 330         info.cache_index = -1;
 331
 332         core = chain->core;
 333
 334         for (;;) {
 335                 /*
 336                  * Unwind deep recursions which had been deferred.  This
 337                  * can leave MOVED set for these chains, which will be
 338                  * handled when we [re]flush chain after the unwind.
 339                  */
 340                 while ((scan = TAILQ_FIRST(&info.flush_list)) != NULL) {
 341                         KKASSERT(scan->flags & HAMMER2_CHAIN_DEFERRED);
 342                         TAILQ_REMOVE(&info.flush_list, scan, flush_node);
 343                         atomic_clear_int(&scan->flags, HAMMER2_CHAIN_DEFERRED);
 344
 345                         /*
 346                          * Now that we've popped back up we can do a secondary
 347                          * recursion on the deferred elements.
 348                          */
 349                         if (hammer2_debug & 0x0040)
 350                                 kprintf("defered flush %p\n", scan);
 351                         hammer2_chain_lock(scan, HAMMER2_RESOLVE_MAYBE);
 352                         hammer2_chain_flush(trans, scan);
 353                         hammer2_chain_unlock(scan);
 354                         hammer2_chain_drop(scan);       /* ref from deferral */
 355                 }
 356
 357                 /*
 358                  * Flush pass1 on root.
 359                  */
 360                 info.diddeferral = 0;
 361                 hammer2_chain_flush_core(&info, chain);
 362 #if FLUSH_DEBUG
 363                 kprintf("flush_core_done parent=<base> chain=%p.%d %08x\n",
 364                         chain, chain->bref.type, chain->flags);
 365 #endif
 366
 367                 /*
 368                  * Only loop if deep recursions have been deferred.
 369                  */
 370                 if (TAILQ_EMPTY(&info.flush_list))
 371                         break;
 372         }
 373 }
 374
 375 /*
 376  * This is the core of the chain flushing code.  The chain is locked by the
 377  * caller and remains locked on return.  This function is keyed off of
 378  * the SUBMODIFIED bit but must make fine-grained choices based on the
 379  * synchronization point we are flushing to.
 380  *
 381  * If the flush accomplished any work chain will be flagged MOVED
 382  * indicating a copy-on-write propagation back up is required.
 383  * Deep sub-nodes may also have been entered onto the deferral list.
 384  * MOVED is never set on the volume root.
 385  *
 386  * NOTE: modify_tid is different from MODIFIED.  modify_tid is updated
 387  *       only when a chain is specifically modified, and not updated
 388  *       for copy-on-write propagations.  MODIFIED is set on any modification
 389  *       including copy-on-write propagations.
 390  */
 391 static void
 392 hammer2_chain_flush_core(hammer2_flush_info_t *info, hammer2_chain_t *chain)
 393 {
 394         hammer2_mount_t *hmp;
 395         hammer2_blockref_t *bref;
 396         hammer2_off_t pbase;
 397         hammer2_off_t pmask;
 398         hammer2_tid_t saved_sync;
 399         hammer2_trans_t *trans = info->trans;
 400         hammer2_chain_core_t *core;
 401         size_t psize;
 402         size_t boff;
 403         char *bdata;
 404         struct buf *bp;
 405         int error;
 406         int wasmodified;
 407         int diddeferral = 0;
 408
 409         hmp = chain->hmp;
 410
 411 #if FLUSH_DEBUG
 412         if (info->parent)
 413                 kprintf("flush_core %p->%p.%d %08x (%s)\n",
 414                         info->parent, chain, chain->bref.type,
 415                         chain->flags,
 416                         ((chain->bref.type == HAMMER2_BREF_TYPE_INODE) ?
 417                                 chain->data->ipdata.filename : "?"));
 418         else
 419                 kprintf("flush_core NULL->%p.%d %08x (%s)\n",
 420                         chain, chain->bref.type,
 421                         chain->flags,
 422                         ((chain->bref.type == HAMMER2_BREF_TYPE_INODE) ?
 423                                 chain->data->ipdata.filename : "?"));
 424 #endif
 425         /*
 426          * Ignore chains modified beyond the current flush point.  These
 427          * will be treated as if they did not exist.
 428          */
 429         if (chain->modify_tid > info->sync_tid)
 430                 return;
 431
 432         /*
 433          * Deleted chains which have not been destroyed must be retained,
 434          * and we probably have to recurse to clean-up any sub-trees.
 435          * However, restricted flushes can stop processing here because
 436          * the chain cleanup will be handled by a later normal flush.
 437          *
 438          * The MODIFIED bit can likely be cleared in this situation and we
 439          * will do so later on in this procedure.
 440          */
 441         if (chain->delete_tid <= info->sync_tid) {
 442                 if (trans->flags & HAMMER2_TRANS_RESTRICTED)
 443                         return;
 444         }
 445
 446         saved_sync = info->sync_tid;
 447         core = chain->core;
 448
 449         /*
 450          * If SUBMODIFIED is set we recurse the flush and adjust the
 451          * blockrefs accordingly.
 452          *
 453          * NOTE: Looping on SUBMODIFIED can prevent a flush from ever
 454          *       finishing in the face of filesystem activity.
 455          */
 456         if (chain->flags & HAMMER2_CHAIN_SUBMODIFIED) {
 457                 hammer2_chain_t *saved_parent;
 458                 hammer2_tid_t saved_mirror;
 459                 hammer2_chain_layer_t *layer;
 460
 461                 /*
 462                  * Clear SUBMODIFIED to catch races.  Note that any child
 463                  * with MODIFIED, DELETED, or MOVED set during scan2, or
 464                  * which tries to lastdrop but can't free its structures,
 465                  * or which gets defered, will cause SUBMODIFIED to be set
 466                  * again.
 467                  *
 468                  * We don't want to set our chain to MODIFIED gratuitously.
 469                  *
 470                  * We need an extra ref on chain because we are going to
 471                  * release its lock temporarily in our child loop.
 472                  */
 473                 atomic_clear_int(&chain->flags, HAMMER2_CHAIN_SUBMODIFIED);
 474                 hammer2_chain_ref(chain);
 475
 476                 /*
 477                  * Run two passes.  The first pass handles MODIFIED and
 478                  * SUBMODIFIED chains and recurses while the second pass
 479                  * handles MOVED chains on the way back up.
 480                  *
 481                  * If the stack gets too deep we defer scan1, but must
 482                  * be sure to still run scan2 if on the next loop the
 483                  * deferred chain has been flushed and now needs MOVED
 484                  * handling on the way back up.
 485                  *
 486                  * Scan1 is recursive.
 487                  *
 488                  * NOTE: The act of handling a modified/submodified chain can
 489                  *       cause the MOVED Flag to be set.  It can also be set
 490                  *       via hammer2_chain_delete() and in other situations.
 491                  *
 492                  * NOTE: RB_SCAN() must be used instead of RB_FOREACH()
 493                  *       because children can be physically removed during
 494                  *       the scan.
 495                  */
 496                 saved_parent = info->parent;
 497                 saved_mirror = info->mirror_tid;
 498                 info->parent = chain;
 499                 info->mirror_tid = chain->bref.mirror_tid;
 500
 501                 if (info->depth == HAMMER2_FLUSH_DEPTH_LIMIT) {
 502                         if ((chain->flags & HAMMER2_CHAIN_DEFERRED) == 0) {
 503                                 hammer2_chain_ref(chain);
 504                                 TAILQ_INSERT_TAIL(&info->flush_list,
 505                                                   chain, flush_node);
 506                                 atomic_set_int(&chain->flags,
 507                                                HAMMER2_CHAIN_DEFERRED);
 508                         }
 509                         diddeferral = 1;
 510                 } else {
 511                         info->diddeferral = 0;
 512                         spin_lock(&core->cst.spin);
 513                         TAILQ_FOREACH_REVERSE(layer, &core->layerq,
 514                                               h2_layer_list, entry) {
 515                                 ++layer->refs;
 516                                 RB_SCAN(hammer2_chain_tree, &layer->rbtree,
 517                                         NULL, hammer2_chain_flush_scan1, info);
 518                                 --layer->refs;
 519                                 diddeferral += info->diddeferral;
 520                         }
 521                         spin_unlock(&core->cst.spin);
 522                 }
 523
 524                 /*
 525                  * Handle successfully flushed children who are in the MOVED
 526                  * state on the way back up the recursion.  This can have
 527                  * the side-effect of clearing MOVED.
 528                  *
 529                  * Scan2 is non-recursive.
 530                  */
 531                 if (diddeferral) {
 532                         atomic_set_int(&chain->flags,
 533                                        HAMMER2_CHAIN_SUBMODIFIED);
 534                         spin_lock(&core->cst.spin);
 535                 } else {
 536                         spin_lock(&core->cst.spin);
 537                         TAILQ_FOREACH_REVERSE(layer, &core->layerq,
 538                                               h2_layer_list, entry) {
 539                                 info->pass = 1;
 540                                 ++layer->refs;
 541                                 RB_SCAN(hammer2_chain_tree, &layer->rbtree,
 542                                         NULL, hammer2_chain_flush_scan2, info);
 543                                 info->pass = 2;
 544                                 RB_SCAN(hammer2_chain_tree, &layer->rbtree,
 545                                         NULL, hammer2_chain_flush_scan2, info);
 546                                 /*diddeferral += info->diddeferral; n/a*/
 547                                 --layer->refs;
 548                         }
 549                 }
 550                 hammer2_chain_layer_check_locked(chain->hmp, core);
 551                 spin_unlock(&core->cst.spin);
 552
 553                 chain->bref.mirror_tid = info->mirror_tid;
 554                 info->mirror_tid = saved_mirror;
 555                 info->parent = saved_parent;
 556                 hammer2_chain_drop(chain);
 557         }
 558
 559         /*
 560          * Restore sync_tid in case it was restricted by a delete/duplicate.
 561          */
 562         info->sync_tid = saved_sync;
 563
 564         /*
 565          * Rollup diddeferral for caller.  Note direct assignment, not +=.
 566          */
 567         info->diddeferral = diddeferral;
 568
 569         /*
 570          * Do not flush chain if there were any deferrals.  It will be
 571          * retried later after the deferrals are independently handled.
 572          */
 573         if (diddeferral) {
 574                 if (hammer2_debug & 0x0008) {
 575                         kprintf("%*.*s} %p/%d %04x (deferred)",
 576                                 info->depth, info->depth, "",
 577                                 chain, chain->refs, chain->flags);
 578                 }
 579                 return;
 580         }
 581
 582         /*
 583          * If we encounter a deleted chain within our flush we can clear
 584          * the MODIFIED bit and avoid flushing it whether it has been
 585          * destroyed or not.  We must make sure that the chain is flagged
 586          * MOVED in this situation so the parent picks up the deletion.
 587          *
 588          * Note that scan2 has already executed above so statistics have
 589          * already been rolled up.
 590          */
 591         if (chain->delete_tid <= info->sync_tid) {
 592                 if (chain->flags & HAMMER2_CHAIN_MODIFIED) {
 593                         if (chain->bp) {
 594                                 if (chain->bytes == chain->bp->b_bufsize)
 595                                         chain->bp->b_flags |= B_INVAL|B_RELBUF;
 596                         }
 597                         if ((chain->flags & HAMMER2_CHAIN_MOVED) == 0) {
 598                                 hammer2_chain_ref(chain);
 599                                 atomic_set_int(&chain->flags,
 600                                                HAMMER2_CHAIN_MOVED);
 601                         }
 602                         atomic_clear_int(&chain->flags, HAMMER2_CHAIN_MODIFIED);
 603                         hammer2_chain_drop(chain);
 604                 }
 605                 return;
 606         }
 607 #if 0
 608         if ((chain->flags & HAMMER2_CHAIN_DESTROYED) &&
 609             (chain->flags & HAMMER2_CHAIN_DELETED) &&
 610             (trans->flags & HAMMER2_TRANS_RESTRICTED) == 0) {
 611                 /*
 612                  * Throw-away the MODIFIED flag
 613                  */
 614                 if (chain->flags & HAMMER2_CHAIN_MODIFIED) {
 615                         if (chain->bp) {
 616                                 if (chain->bytes == chain->bp->b_bufsize)
 617                                         chain->bp->b_flags |= B_INVAL|B_RELBUF;
 618                         }
 619                         atomic_clear_int(&chain->flags, HAMMER2_CHAIN_MODIFIED);
 620                         hammer2_chain_drop(chain);
 621                 }
 622                 return;
 623         }
 624 #endif
 625
 626         /*
 627          * A degenerate flush might not have flushed anything and thus not
 628          * processed modified blocks on the way back up.  Detect the case.
 629          *
 630          * Note that MOVED can be set without MODIFIED being set due to
 631          * a deletion, in which case it is handled by Scan2 later on.
 632          *
 633          * Both bits can be set along with DELETED due to a deletion if
 634          * modified data within the synchronization zone and the chain
 635          * was then deleted beyond the zone, in which case we still have
 636          * to flush for synchronization point consistency.  Otherwise though
 637          * DELETED and MODIFIED are treated as separate flags.
 638          */
 639         if ((chain->flags & HAMMER2_CHAIN_MODIFIED) == 0)
 640                 return;
 641
 642         /*
 643          * Issue flush.
 644          *
 645          * A DESTROYED node that reaches this point must be flushed for
 646          * synchronization point consistency.
 647          */
 648
 649         /*
 650          * Update mirror_tid, clear MODIFIED, and set MOVED.
 651          *
 652          * The caller will update the parent's reference to this chain
 653          * by testing MOVED as long as the modification was in-bounds.
 654          *
 655          * MOVED is never set on the volume root as there is no parent
 656          * to adjust.
 657          */
 658         if (chain->bref.mirror_tid < info->sync_tid)
 659                 chain->bref.mirror_tid = info->sync_tid;
 660         wasmodified = (chain->flags & HAMMER2_CHAIN_MODIFIED) != 0;
 661         atomic_clear_int(&chain->flags, HAMMER2_CHAIN_MODIFIED);
 662         if (chain == &hmp->vchain)
 663                 kprintf("(FLUSHED VOLUME HEADER)\n");
 664         if (chain == &hmp->fchain)
 665                 kprintf("(FLUSHED FREEMAP HEADER)\n");
 666
 667         if ((chain->flags & HAMMER2_CHAIN_MOVED) ||
 668             chain == &hmp->vchain ||
 669             chain == &hmp->fchain) {
 670                 /*
 671                  * Drop the ref from the MODIFIED bit we cleared.
 672                  */
 673                 if (wasmodified)
 674                         hammer2_chain_drop(chain);
 675         } else {
 676                 /*
 677                  * If we were MODIFIED we inherit the ref from clearing
 678                  * that bit, otherwise we need another ref.
 679                  */
 680                 if (wasmodified == 0)
 681                         hammer2_chain_ref(chain);
 682                 atomic_set_int(&chain->flags, HAMMER2_CHAIN_MOVED);
 683         }
 684
 685         /*
 686          * If this is part of a recursive flush we can go ahead and write
 687          * out the buffer cache buffer and pass a new bref back up the chain
 688          * via the MOVED bit.
 689          *
 690          * Volume headers are NOT flushed here as they require special
 691          * processing.
 692          */
 693         switch(chain->bref.type) {
 694         case HAMMER2_BREF_TYPE_FREEMAP:
 695                 hammer2_modify_volume(hmp);
 696                 break;
 697         case HAMMER2_BREF_TYPE_VOLUME:
 698                 /*
 699                  * We should flush the free block table before we calculate
 700                  * CRCs and copy voldata -> volsync.
 701                  *
 702                  * To prevent SMP races, fchain must remain locked until
 703                  * voldata is copied to volsync.
 704                  */
 705                 hammer2_chain_lock(&hmp->fchain, HAMMER2_RESOLVE_ALWAYS);
 706                 if (hmp->fchain.flags & (HAMMER2_CHAIN_MODIFIED |
 707                                          HAMMER2_CHAIN_SUBMODIFIED)) {
 708                         /* this will modify vchain as a side effect */
 709                         hammer2_chain_flush(info->trans, &hmp->fchain);
 710                 }
 711
 712                 /*
 713                  * The volume header is flushed manually by the syncer, not
 714                  * here.  All we do is adjust the crc's.
 715                  */
 716                 KKASSERT(chain->data != NULL);
 717                 KKASSERT(chain->bp == NULL);
 718                 kprintf("volume header mirror_tid %jd\n",
 719                         hmp->voldata.mirror_tid);
 720
 721                 hmp->voldata.icrc_sects[HAMMER2_VOL_ICRC_SECT1]=
 722                         hammer2_icrc32(
 723                                 (char *)&hmp->voldata +
 724                                  HAMMER2_VOLUME_ICRC1_OFF,
 725                                 HAMMER2_VOLUME_ICRC1_SIZE);
 726                 hmp->voldata.icrc_sects[HAMMER2_VOL_ICRC_SECT0]=
 727                         hammer2_icrc32(
 728                                 (char *)&hmp->voldata +
 729                                  HAMMER2_VOLUME_ICRC0_OFF,
 730                                 HAMMER2_VOLUME_ICRC0_SIZE);
 731                 hmp->voldata.icrc_volheader =
 732                         hammer2_icrc32(
 733                                 (char *)&hmp->voldata +
 734                                  HAMMER2_VOLUME_ICRCVH_OFF,
 735                                 HAMMER2_VOLUME_ICRCVH_SIZE);
 736                 hmp->volsync = hmp->voldata;
 737                 atomic_set_int(&chain->flags, HAMMER2_CHAIN_VOLUMESYNC);
 738                 hammer2_chain_unlock(&hmp->fchain);
 739                 break;
 740         case HAMMER2_BREF_TYPE_DATA:
 741                 /*
 742                  * Data elements have already been flushed via the logical
 743                  * file buffer cache.  Their hash was set in the bref by
 744                  * the vop_write code.
 745                  *
 746                  * Make sure any device buffer(s) have been flushed out here.
 747                  * (there aren't usually any to flush).
 748                  */
 749                 psize = hammer2_devblksize(chain->bytes);
 750                 pmask = (hammer2_off_t)psize - 1;
 751                 pbase = chain->bref.data_off & ~pmask;
 752                 boff = chain->bref.data_off & (HAMMER2_OFF_MASK & pmask);
 753
 754                 bp = getblk(hmp->devvp, pbase, psize, GETBLK_NOWAIT, 0);
 755                 if (bp) {
 756                         if ((bp->b_flags & (B_CACHE | B_DIRTY)) ==
 757                             (B_CACHE | B_DIRTY)) {
 758                                 cluster_awrite(bp);
 759                         } else {
 760                                 bp->b_flags |= B_RELBUF;
 761                                 brelse(bp);
 762                         }
 763                 }
 764                 break;
 765 #if 0
 766         case HAMMER2_BREF_TYPE_INDIRECT:
 767                 /*
 768                  * Indirect blocks may be in an INITIAL state.  Use the
 769                  * chain_lock() call to ensure that the buffer has been
 770                  * instantiated (even though it is already locked the buffer
 771                  * might not have been instantiated).
 772                  *
 773                  * Only write the buffer out if it is dirty, it is possible
 774                  * the operating system had already written out the buffer.
 775                  */
 776                 hammer2_chain_lock(chain, HAMMER2_RESOLVE_ALWAYS);
 777                 KKASSERT(chain->bp != NULL);
 778
 779                 bp = chain->bp;
 780                 if ((chain->flags & HAMMER2_CHAIN_DIRTYBP) ||
 781                     (bp->b_flags & B_DIRTY)) {
 782                         bdwrite(chain->bp);
 783                 } else {
 784                         brelse(chain->bp);
 785                 }
 786                 chain->bp = NULL;
 787                 chain->data = NULL;
 788                 hammer2_chain_unlock(chain);
 789                 break;
 790 #endif
 791         case HAMMER2_BREF_TYPE_INDIRECT:
 792         case HAMMER2_BREF_TYPE_FREEMAP_NODE:
 793                 /*
 794                  * Device-backed.  Buffer will be flushed by the sync
 795                  * code XXX.
 796                  */
 797                 KKASSERT((chain->flags & HAMMER2_CHAIN_EMBEDDED) == 0);
 798                 break;
 799         case HAMMER2_BREF_TYPE_FREEMAP_LEAF:
 800         default:
 801                 /*
 802                  * Embedded elements have to be flushed out.
 803                  * (Basically just BREF_TYPE_INODE).
 804                  */
 805                 KKASSERT(chain->flags & HAMMER2_CHAIN_EMBEDDED);
 806                 KKASSERT(chain->data != NULL);
 807                 KKASSERT(chain->bp == NULL);
 808                 bref = &chain->bref;
 809
 810                 KKASSERT((bref->data_off & HAMMER2_OFF_MASK) != 0);
 811                 KKASSERT(HAMMER2_DEC_CHECK(chain->bref.methods) ==
 812                          HAMMER2_CHECK_ISCSI32 ||
 813                          HAMMER2_DEC_CHECK(chain->bref.methods) ==
 814                          HAMMER2_CHECK_FREEMAP);
 815
 816                 /*
 817                  * The data is embedded, we have to acquire the
 818                  * buffer cache buffer and copy the data into it.
 819                  */
 820                 psize = hammer2_devblksize(chain->bytes);
 821                 pmask = (hammer2_off_t)psize - 1;
 822                 pbase = bref->data_off & ~pmask;
 823                 boff = bref->data_off & (HAMMER2_OFF_MASK & pmask);
 824
 825                 /*
 826                  * The getblk() optimization can only be used if the
 827                  * physical block size matches the request.
 828                  */
 829                 error = bread(hmp->devvp, pbase, psize, &bp);
 830                 KKASSERT(error == 0);
 831
 832                 bdata = (char *)bp->b_data + boff;
 833
 834                 /*
 835                  * Copy the data to the buffer, mark the buffer
 836                  * dirty, and convert the chain to unmodified.
 837                  */
 838                 bcopy(chain->data, bdata, chain->bytes);
 839                 bp->b_flags |= B_CLUSTEROK;
 840                 bdwrite(bp);
 841                 bp = NULL;
 842
 843                 switch(HAMMER2_DEC_CHECK(chain->bref.methods)) {
 844                 case HAMMER2_CHECK_FREEMAP:
 845                         chain->bref.check.freemap.icrc32 =
 846                                 hammer2_icrc32(chain->data, chain->bytes);
 847                         break;
 848                 case HAMMER2_CHECK_ISCSI32:
 849                         chain->bref.check.iscsi32.value =
 850                                 hammer2_icrc32(chain->data, chain->bytes);
 851                         break;
 852                 default:
 853                         panic("hammer2_flush_core: bad crc type");
 854                         break; /* NOT REACHED */
 855                 }
 856                 if (chain->bref.type == HAMMER2_BREF_TYPE_INODE)
 857                         ++hammer2_iod_meta_write;
 858                 else
 859                         ++hammer2_iod_indr_write;
 860         }
 861 }
 862
 863 /*
 864  * Flush helper scan1 (recursive)
 865  *
 866  * Flushes the children of the caller's chain (parent) and updates
 867  * the blockref, restricted by sync_tid.
 868  *
 869  * Ripouts during the loop should not cause any problems.  Because we are
 870  * flushing to a synchronization point, modification races will occur after
 871  * sync_tid and do not have to be flushed anyway.
 872  *
 873  * It is also ok if the parent is chain_duplicate()'d while unlocked because
 874  * the delete/duplication will install a delete_tid that is still larger than
 875  * our current sync_tid.
 876  */
 877 static int
 878 hammer2_chain_flush_scan1(hammer2_chain_t *child, void *data)
 879 {
 880         hammer2_flush_info_t *info = data;
 881         hammer2_trans_t *trans = info->trans;
 882         hammer2_chain_t *parent = info->parent;
 883         int diddeferral;
 884
 885         /*
 886          * We should only need to recurse if SUBMODIFIED is set, but as
 887          * a safety also recurse if MODIFIED is also set.
 888          *
 889          * Return early if neither bit is set.  We must re-assert the
 890          * SUBMODIFIED flag in the parent if any child covered by the
 891          * parent (via delete_tid) is skipped.
 892          */
 893         if ((child->flags & (HAMMER2_CHAIN_MODIFIED |
 894                              HAMMER2_CHAIN_SUBMODIFIED)) == 0) {
 895                 return (0);
 896         }
 897         if (child->modify_tid > trans->sync_tid) {
 898                 if (parent->delete_tid > trans->sync_tid) {
 899                         atomic_set_int(&parent->flags,
 900                                        HAMMER2_CHAIN_SUBMODIFIED);
 901                 }
 902                 return (0);
 903         }
 904
 905         hammer2_chain_ref(child);
 906         spin_unlock(&parent->core->cst.spin);
 907
 908         /*
 909          * The caller has added a ref to the parent so we can temporarily
 910          * unlock it in order to lock the child.  Re-check the flags before
 911          * continuing.
 912          */
 913         hammer2_chain_unlock(parent);
 914         hammer2_chain_lock(child, HAMMER2_RESOLVE_MAYBE);
 915
 916         if ((child->flags & (HAMMER2_CHAIN_MODIFIED |
 917                              HAMMER2_CHAIN_SUBMODIFIED)) == 0) {
 918                 hammer2_chain_unlock(child);
 919                 hammer2_chain_drop(child);
 920                 hammer2_chain_lock(parent, HAMMER2_RESOLVE_MAYBE);
 921                 spin_lock(&parent->core->cst.spin);
 922                 return (0);
 923         }
 924         if (child->modify_tid > trans->sync_tid) {
 925                 hammer2_chain_unlock(child);
 926                 hammer2_chain_drop(child);
 927                 hammer2_chain_lock(parent, HAMMER2_RESOLVE_MAYBE);
 928                 spin_lock(&parent->core->cst.spin);
 929                 if (parent->delete_tid > trans->sync_tid) {
 930                         atomic_set_int(&parent->flags,
 931                                        HAMMER2_CHAIN_SUBMODIFIED);
 932                 }
 933                 return (0);
 934         }
 935
 936         /*
 937          * The DESTROYED flag can only be initially set on an unreferenced
 938          * deleted inode and will propagate downward via the mechanic below.
 939          * Such inode chains have been deleted for good and should no longer
 940          * be subject to delete/duplication.
 941          *
 942          * This optimization allows the inode reclaim (destroy unlinked file
 943          * on vnode reclamation after last close) to be flagged by just
 944          * setting HAMMER2_CHAIN_DESTROYED at the top level and then will
 945          * cause the chains to be terminated and related buffers to be
 946          * invalidated and not flushed out.
 947          *
 948          * We have to be careful not to propagate the DESTROYED flag if
 949          * the destruction occurred after our flush sync_tid.
 950          */
 951         if ((parent->flags & HAMMER2_CHAIN_DESTROYED) &&
 952             (child->flags & HAMMER2_CHAIN_DELETED) &&
 953             (child->flags & HAMMER2_CHAIN_DESTROYED) == 0) {
 954                 atomic_set_int(&child->flags, HAMMER2_CHAIN_DESTROYED |
 955                                               HAMMER2_CHAIN_SUBMODIFIED);
 956         }
 957
 958         /*
 959          * Recurse and collect deferral data.
 960          */
 961         diddeferral = info->diddeferral;
 962         ++info->depth;
 963         hammer2_chain_flush_core(info, child);
 964 #if FLUSH_DEBUG
 965         kprintf("flush_core_done parent=%p flags=%08x child=%p.%d %08x\n",
 966                 parent, parent->flags, child, child->bref.type, child->flags);
 967 #endif
 968         --info->depth;
 969         info->diddeferral += diddeferral;
 970
 971         if (child->flags & HAMMER2_CHAIN_SUBMODIFIED)
 972                 atomic_set_int(&parent->flags, HAMMER2_CHAIN_SUBMODIFIED);
 973
 974         hammer2_chain_unlock(child);
 975         hammer2_chain_drop(child);
 976
 977         hammer2_chain_lock(parent, HAMMER2_RESOLVE_MAYBE);
 978
 979         spin_lock(&parent->core->cst.spin);
 980
 981         return (0);
 982 }
 983
 984 /*
 985  * Flush helper scan2 (non-recursive)
 986  *
 987  * This pass on a chain's children propagates any MOVED or DELETED
 988  * elements back up the chain towards the root after those elements have
 989  * been fully flushed.  Unlike scan1, this function is NOT recursive and
 990  * the parent remains locked across the entire scan.
 991  *
 992  * SCAN2 is called twice, once with pass set to 1 and once with it set to 2.
 993  * We have to do this so base[] elements can be deleted in pass 1 to make
 994  * room for adding new elements in pass 2.
 995  *
 996  * This function also rolls up storage statistics.
 997  *
 998  * NOTE!  We must re-set SUBMODIFIED on the parent(s) as appropriate, and
 999  *        due to the above conditions it is possible to do this and still
1000  *        have some children flagged MOVED depending on the synchronization.
1001  *
1002  * NOTE!  A deletion is a visbility issue, there can still be references to
1003  *        deleted elements (for example, to an unlinked file which is still
1004  *        open), and there can also be multiple chains pointing to the same
1005  *        bref where some are deleted and some are not (for example due to
1006  *        a rename).   So a chain marked for deletion is basically considered
1007  *        to be live until it is explicitly destroyed or until its ref-count
1008  *        reaches zero (also implying that MOVED and MODIFIED are clear).
1009  */
1010 static int
1011 hammer2_chain_flush_scan2(hammer2_chain_t *child, void *data)
1012 {
1013         hammer2_flush_info_t *info = data;
1014         hammer2_chain_t *parent = info->parent;
1015         hammer2_chain_core_t *above = child->above;
1016         hammer2_mount_t *hmp = child->hmp;
1017         hammer2_trans_t *trans = info->trans;
1018         hammer2_blockref_t *base;
1019         int count;
1020         int ok;
1021
1022         /*
1023          * Inodes with stale children that have been converted to DIRECTDATA
1024          * mode (file extension or hardlink conversion typically) need to
1025          * skipped right now before we start messing with a non-existant
1026          * block table.
1027          */
1028 #if 0
1029         if (parent->bref.type == HAMMER2_BREF_TYPE_INODE &&
1030             (parent->data->ipdata.op_flags & HAMMER2_OPFLAG_DIRECTDATA)) {
1031                 goto finalize;
1032         }
1033 #endif
1034
1035         /*
1036          * Ignore children created after our flush point, treating them as
1037          * if they did not exist).  These children will not cause the parent
1038          * to be updated.
1039          *
1040          * When we encounter such children and the parent chain has not been
1041          * deleted, delete/duplicated, or delete/duplicated-for-move, then
1042          * the parent may be used to funnel through several flush points.
1043          * We must re-set the SUBMODIFIED flag in the parent to ensure that
1044          * those flushes have visbility.  A simple test of delete_tid suffices
1045          * to determine if the parent spans beyond our current flush.
1046          */
1047         if (child->modify_tid > trans->sync_tid) {
1048                 goto finalize;
1049         }
1050
1051         /*
1052          * Ignore children which have not changed.  The parent's block table
1053          * is already correct.
1054          *
1055          * XXX The MOVED bit is only cleared when all multi-homed parents
1056          *     have flushed, creating a situation where a re-flush can occur
1057          *     via a parent which has already flushed.  The hammer2_base_*()
1058          *     functions currently have a hack to deal with this case but
1059          *     we need something better.
1060          */
1061         if ((child->flags & HAMMER2_CHAIN_MOVED) == 0) {
1062                 goto finalize;
1063         }
1064
1065         /*
1066          * Make sure child is referenced before we unlock.
1067          */
1068         hammer2_chain_ref(child);
1069         spin_unlock(&above->cst.spin);
1070
1071         /*
1072          * Parent reflushed after the child has passed them by should skip
1073          * due to the modify_tid test. XXX
1074          */
1075         hammer2_chain_lock(child, HAMMER2_RESOLVE_NEVER);
1076         KKASSERT(child->above == above);
1077         KKASSERT(parent->core == above);
1078
1079         /*
1080          * The parent's blockref to the child must be deleted or updated.
1081          *
1082          * This point is not reached on successful DESTROYED optimizations
1083          * but can be reached on recursive deletions and restricted flushes.
1084          *
1085          * Because flushes are ordered we do not have to make a
1086          * modify/duplicate of indirect blocks.  That is, the flush
1087          * code does not have to kmalloc or duplicate anything.  We
1088          * can adjust the indirect block table in-place and reuse the
1089          * chain.  It IS possible that the chain has already been duplicated
1090          * or may wind up being duplicated on-the-fly by modifying code
1091          * on the frontend.  We simply use the original and ignore such
1092          * chains.  However, it does mean we can't clear the MOVED bit.
1093          *
1094          * XXX recursive deletions not optimized.
1095          */
1096         hammer2_chain_modify(trans, &parent,
1097                              HAMMER2_MODIFY_NO_MODIFY_TID |
1098                              HAMMER2_MODIFY_ASSERTNOCOPY);
1099
1100         switch(parent->bref.type) {
1101         case HAMMER2_BREF_TYPE_INODE:
1102                 /*
1103                  * XXX Should assert that OPFLAG_DIRECTDATA is 0 once we
1104                  * properly duplicate the inode headers and do proper flush
1105                  * range checks (all the children should be beyond the flush
1106                  * point).  For now just don't sync the non-applicable
1107                  * children.
1108                  *
1109                  * XXX Can also occur due to hardlink consolidation.  We
1110                  * set OPFLAG_DIRECTDATA to prevent the indirect and data
1111                  * blocks from syncing ot the hardlink pointer.
1112                  */
1113 #if 0
1114                 KKASSERT((parent->data->ipdata.op_flags &
1115                           HAMMER2_OPFLAG_DIRECTDATA) == 0);
1116 #endif
1117 #if 0
1118                 if (parent->data->ipdata.op_flags & HAMMER2_OPFLAG_DIRECTDATA) {
1119                         base = NULL;
1120                 } else
1121 #endif
1122                 {
1123                         base = &parent->data->ipdata.u.blockset.blockref[0];
1124                         count = HAMMER2_SET_COUNT;
1125                 }
1126                 break;
1127         case HAMMER2_BREF_TYPE_INDIRECT:
1128         case HAMMER2_BREF_TYPE_FREEMAP_NODE:
1129                 if (parent->data) {
1130                         base = &parent->data->npdata[0];
1131                 } else {
1132                         base = NULL;
1133                         KKASSERT(child->flags & HAMMER2_CHAIN_DELETED);
1134                 }
1135                 count = parent->bytes / sizeof(hammer2_blockref_t);
1136                 break;
1137         case HAMMER2_BREF_TYPE_VOLUME:
1138                 base = &hmp->voldata.sroot_blockset.blockref[0];
1139                 count = HAMMER2_SET_COUNT;
1140                 break;
1141         case HAMMER2_BREF_TYPE_FREEMAP:
1142                 base = &parent->data->npdata[0];
1143                 count = HAMMER2_SET_COUNT;
1144                 break;
1145         default:
1146                 base = NULL;
1147                 count = 0;
1148                 panic("hammer2_chain_flush_scan2: "
1149                       "unrecognized blockref type: %d",
1150                       parent->bref.type);
1151         }
1152
1153         /*
1154          * Don't bother updating a deleted parent's blockrefs (caller will
1155          * optimize-out the disk write).  Note that this is not optional,
1156          * a deleted parent's blockref array might not be synchronized at
1157          * all so calling hammer2_base*() functions could result in a panic.
1158          *
1159          * Otherwise, we need to be COUNTEDBREFS synchronized for the
1160          * hammer2_base_*() functions.
1161          */
1162         if (parent->delete_tid <= trans->sync_tid)
1163                 base = NULL;
1164         else if ((above->flags & HAMMER2_CORE_COUNTEDBREFS) == 0)
1165                 hammer2_chain_countbrefs(above, base, count);
1166
1167         /*
1168          * Update the parent's blockref table and propagate mirror_tid.
1169          *
1170          * NOTE! Children with modify_tid's beyond our flush point are
1171          *       considered to not exist for the purposes of updating the
1172          *       parent's blockref array.
1173          *
1174          * NOTE! Updates to a parent's blockref table do not adjust the
1175          *       parent's bref.modify_tid, only its bref.mirror_tid.
1176          */
1177         if (info->pass == 1 && child->delete_tid <= trans->sync_tid) {
1178                 /*
1179                  * Deleting.  Only adjust the block array if it contains
1180                  * the child's entry (child's REPLACE flag is set).  Clear
1181                  * the child's REPLACE flag only once all possible parent's
1182                  * have been updated.
1183                  */
1184                 ok = 1;
1185                 if (base && (child->flags & HAMMER2_CHAIN_REPLACE)) {
1186                         hammer2_rollup_stats(parent, child, -1);
1187                         spin_lock(&above->cst.spin);
1188                         hammer2_base_delete(base, count, above,
1189                                             &info->cache_index, &child->bref);
1190                         if (TAILQ_NEXT(parent, core_entry) == NULL) {
1191                                 atomic_clear_int(&child->flags,
1192                                                HAMMER2_CHAIN_REPLACE);
1193                         }
1194                         spin_unlock(&above->cst.spin);
1195                 }
1196                 if (info->mirror_tid < child->delete_tid)
1197                         info->mirror_tid = child->delete_tid;
1198         } else if (info->pass == 2 && child->delete_tid > trans->sync_tid) {
1199                 /*
1200                  * Inserting.  Only set the child's REPLACE flag indicating
1201                  * that the parent's blockref array entry is valid once all
1202                  * possible parent's have been updated.
1203                  */
1204                 ok = 1;
1205                 if (base) {
1206                         if (child->flags & HAMMER2_CHAIN_REPLACE)
1207                                 hammer2_rollup_stats(parent, child, 0);
1208                         else
1209                                 hammer2_rollup_stats(parent, child, 1);
1210                         spin_lock(&above->cst.spin);
1211                         hammer2_base_insert(base, count, above,
1212                                             &info->cache_index, &child->bref,
1213                                             child->flags);
1214                         if (TAILQ_NEXT(parent, core_entry) == NULL) {
1215                                 atomic_set_int(&child->flags,
1216                                                HAMMER2_CHAIN_REPLACE);
1217                         }
1218                         spin_unlock(&above->cst.spin);
1219                 }
1220                 if (info->mirror_tid < child->modify_tid)
1221                         info->mirror_tid = child->modify_tid;
1222         } else {
1223                 ok = 0;
1224         }
1225
1226         if (info->mirror_tid < child->bref.mirror_tid) {
1227                 info->mirror_tid = child->bref.mirror_tid;
1228         }
1229         if ((parent->bref.type == HAMMER2_BREF_TYPE_VOLUME ||
1230              parent->bref.type == HAMMER2_BREF_TYPE_FREEMAP) &&
1231             hmp->voldata.mirror_tid < child->bref.mirror_tid) {
1232                 hmp->voldata.mirror_tid = child->bref.mirror_tid;
1233         }
1234
1235         /*
1236          * Only clear MOVED once all possible parents have been flushed.
1237          *
1238          * When can we safely clear the MOVED flag?  Flushes down duplicate
1239          * paths can occur out of order, for example if an inode is moved
1240          * as part of a hardlink consolidation or if an inode is moved into
1241          * an indirect block indexed before the inode.
1242          */
1243         if (ok && (child->flags & HAMMER2_CHAIN_MOVED)) {
1244                 hammer2_chain_t *scan;
1245                 int ok = 1;
1246
1247                 spin_lock(&above->cst.spin);
1248                 TAILQ_FOREACH(scan, &above->ownerq, core_entry) {
1249                         /*
1250                          * XXX weird code also checked at the top of scan2,
1251                          *     I would like to fix this by detaching the core
1252                          *     on initial hardlink consolidation (1->2 nlinks).
1253                          */
1254 #if 0
1255                         if (scan->bref.type == HAMMER2_BREF_TYPE_INODE &&
1256                             (scan->data->ipdata.op_flags &
1257                              HAMMER2_OPFLAG_DIRECTDATA)) {
1258                                 continue;
1259                         }
1260 #endif
1261                         if (scan->flags & HAMMER2_CHAIN_SUBMODIFIED) {
1262                                 ok = 0;
1263                                 break;
1264                         }
1265                 }
1266                 spin_unlock(&above->cst.spin);
1267                 if (ok) {
1268                         atomic_clear_int(&child->flags, HAMMER2_CHAIN_MOVED);
1269                         hammer2_chain_drop(child);      /* flag */
1270                 }
1271         }
1272
1273         /*
1274          * Unlock the child.  This can wind up dropping the child's
1275          * last ref, removing it from the parent's RB tree, and deallocating
1276          * the structure.  The RB_SCAN() our caller is doing handles the
1277          * situation.
1278          */
1279         hammer2_chain_unlock(child);
1280         hammer2_chain_drop(child);
1281         spin_lock(&above->cst.spin);
1282
1283         /*
1284          * The parent cleared SUBMODIFIED prior to the scan.  If the child
1285          * still requires a flush (possibly due to being outside the current
1286          * synchronization zone), we must re-set SUBMODIFIED on the way back
1287          * up.
1288          */
1289 finalize:
1290         return (0);
1291 }
1292
1293 static
1294 void
1295 hammer2_rollup_stats(hammer2_chain_t *parent, hammer2_chain_t *child, int how)
1296 {
1297 #if 0
1298         hammer2_chain_t *grandp;
1299 #endif
1300
1301         parent->data_count += child->data_count;
1302         parent->inode_count += child->inode_count;
1303         child->data_count = 0;
1304         child->inode_count = 0;
1305         if (how < 0) {
1306                 parent->data_count -= child->bytes;
1307                 if (child->bref.type == HAMMER2_BREF_TYPE_INODE) {
1308                         parent->inode_count -= 1;
1309 #if 0
1310                         /* XXX child->data may be NULL atm */
1311                         parent->data_count -= child->data->ipdata.data_count;
1312                         parent->inode_count -= child->data->ipdata.inode_count;
1313 #endif
1314                 }
1315         } else if (how > 0) {
1316                 parent->data_count += child->bytes;
1317                 if (child->bref.type == HAMMER2_BREF_TYPE_INODE) {
1318                         parent->inode_count += 1;
1319 #if 0
1320                         /* XXX child->data may be NULL atm */
1321                         parent->data_count += child->data->ipdata.data_count;
1322                         parent->inode_count += child->data->ipdata.inode_count;
1323 #endif
1324                 }
1325         }
1326         if (parent->bref.type == HAMMER2_BREF_TYPE_INODE) {
1327                 parent->data->ipdata.data_count += parent->data_count;
1328                 parent->data->ipdata.inode_count += parent->inode_count;
1329 #if 0
1330                 for (grandp = parent->above->first_parent;
1331                      grandp;
1332                      grandp = grandp->next_parent) {
1333                         grandp->data_count += parent->data_count;
1334                         grandp->inode_count += parent->inode_count;
1335                 }
1336 #endif
1337                 parent->data_count = 0;
1338                 parent->inode_count = 0;
1339         }
1340 }