sys/vfs/hammer2/hammer2_flush.c

   1 /*
   2  * Copyright (c) 2011-2018 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  *                      TRANSACTION AND FLUSH HANDLING
  37  *
  38  * Deceptively simple but actually fairly difficult to implement properly is
  39  * how I would describe it.
  40  *
  41  * Flushing generally occurs bottom-up but requires a top-down scan to
  42  * locate chains with MODIFIED and/or UPDATE bits set.  The ONFLUSH flag
  43  * tells how to recurse downward to find these chains.
  44  */
  45
  46 #include <sys/cdefs.h>
  47 #include <sys/param.h>
  48 #include <sys/systm.h>
  49 #include <sys/types.h>
  50 #include <sys/lock.h>
  51 #include <sys/vnode.h>
  52 #include <sys/buf.h>
  53
  54 #include "hammer2.h"
  55
  56 #define HAMMER2_FLUSH_DEPTH_LIMIT       60      /* stack recursion limit */
  57
  58
  59 /*
  60  * Recursively flush the specified chain.  The chain is locked and
  61  * referenced by the caller and will remain so on return.  The chain
  62  * will remain referenced throughout but can temporarily lose its
  63  * lock during the recursion to avoid unnecessarily stalling user
  64  * processes.
  65  */
  66 struct hammer2_flush_info {
  67         hammer2_chain_t *parent;
  68         int             depth;
  69         int             error;                  /* cumulative error */
  70         int             flags;
  71 #ifdef HAMMER2_SCAN_DEBUG
  72         long            scan_count;
  73         long            scan_mod_count;
  74         long            scan_upd_count;
  75         long            scan_onf_count;
  76         long            scan_del_count;
  77         long            scan_btype[7];
  78 #endif
  79 };
  80
  81 typedef struct hammer2_flush_info hammer2_flush_info_t;
  82
  83 static int hammer2_flush_core(hammer2_flush_info_t *info,
  84                                 hammer2_chain_t *chain, int flags);
  85 static int hammer2_flush_recurse(hammer2_chain_t *child, void *data);
  86
  87 /*
  88  * Any per-pfs transaction initialization goes here.
  89  */
  90 void
  91 hammer2_trans_manage_init(hammer2_pfs_t *pmp)
  92 {
  93 }
  94
  95 /*
  96  * Transaction support for any modifying operation.  Transactions are used
  97  * in the pmp layer by the frontend and in the spmp layer by the backend.
  98  *
  99  * 0                    - Normal transaction.  Interlocks against just the
 100  *                        COPYQ portion of an ISFLUSH transaction.
 101  *
 102  * TRANS_ISFLUSH        - Flush transaction.  Interlocks against other flush
 103  *                        transactions.
 104  *
 105  *                        When COPYQ is also specified, waits for the count
 106  *                        to drop to 1.
 107  *
 108  * TRANS_BUFCACHE       - Buffer cache transaction.  No interlock.
 109  *
 110  * TRANS_SIDEQ          - Run the sideq (only tested in trans_done())
 111  *
 112  * Initializing a new transaction allocates a transaction ID.  Typically
 113  * passed a pmp (hmp passed as NULL), indicating a cluster transaction.  Can
 114  * be passed a NULL pmp and non-NULL hmp to indicate a transaction on a single
 115  * media target.  The latter mode is used by the recovery code.
 116  */
 117 void
 118 hammer2_trans_init(hammer2_pfs_t *pmp, uint32_t flags)
 119 {
 120         uint32_t oflags;
 121         uint32_t nflags;
 122         int dowait;
 123
 124         for (;;) {
 125                 oflags = pmp->trans.flags;
 126                 cpu_ccfence();
 127                 dowait = 0;
 128
 129                 if (flags & HAMMER2_TRANS_ISFLUSH) {
 130                         /*
 131                          * Interlock against other flush transactions.
 132                          */
 133                         if (oflags & HAMMER2_TRANS_ISFLUSH) {
 134                                 nflags = oflags | HAMMER2_TRANS_WAITING;
 135                                 dowait = 1;
 136                         } else {
 137                                 nflags = (oflags | flags) + 1;
 138                         }
 139                 } else if (flags & HAMMER2_TRANS_BUFCACHE) {
 140                         /*
 141                          * Requesting strategy transaction from buffer-cache,
 142                          * or a VM getpages/putpages through the buffer cache.
 143                          * We must allow such transactions in all situations
 144                          * to avoid deadlocks.
 145                          */
 146                         nflags = (oflags | flags) + 1;
 147                 } else {
 148                         /*
 149                          * Normal transaction.  We do not interlock against
 150                          * BUFCACHE or ISFLUSH.
 151                          *
 152                          * Note that vnode locks may be held going into
 153                          * this call.
 154                          *
 155                          * NOTE: Remember that non-modifying operations
 156                          *       such as read, stat, readdir, etc, do
 157                          *       not use transactions.
 158                          */
 159                         nflags = (oflags | flags) + 1;
 160                 }
 161                 if (dowait)
 162                         tsleep_interlock(&pmp->trans.sync_wait, 0);
 163                 if (atomic_cmpset_int(&pmp->trans.flags, oflags, nflags)) {
 164                         if (dowait == 0)
 165                                 break;
 166                         tsleep(&pmp->trans.sync_wait, PINTERLOCKED,
 167                                "h2trans", hz);
 168                         /* retry */
 169                 } else {
 170                         cpu_pause();
 171                         /* retry */
 172                 }
 173                 /* retry */
 174         }
 175
 176 #if 0
 177         /*
 178          * When entering a FLUSH transaction with COPYQ set, wait for the
 179          * transaction count to drop to 1 (our flush transaction only)
 180          * before proceeding.
 181          *
 182          * This waits for all non-flush transactions to complete and blocks
 183          * new non-flush transactions from starting until COPYQ is cleared.
 184          * (the flush will then proceed after clearing COPYQ).  This should
 185          * be a very short stall on modifying operations.
 186          */
 187         while ((flags & HAMMER2_TRANS_ISFLUSH) &&
 188                (flags & HAMMER2_TRANS_COPYQ)) {
 189                 oflags = pmp->trans.flags;
 190                 cpu_ccfence();
 191                 if ((oflags & HAMMER2_TRANS_MASK) == 1)
 192                         break;
 193                 nflags = oflags | HAMMER2_TRANS_WAITING;
 194                 tsleep_interlock(&pmp->trans.sync_wait, 0);
 195                 if (atomic_cmpset_int(&pmp->trans.flags, oflags, nflags)) {
 196                         tsleep(&pmp->trans.sync_wait, PINTERLOCKED,
 197                                "h2trans2", hz);
 198                 }
 199         }
 200 #endif
 201 }
 202
 203 /*
 204  * Start a sub-transaction, there is no 'subdone' function.  This will
 205  * issue a new modify_tid (mtid) for the current transaction, which is a
 206  * CLC (cluster level change) id and not a per-node id.
 207  *
 208  * This function must be called for each XOP when multiple XOPs are run in
 209  * sequence within a transaction.
 210  *
 211  * Callers typically update the inode with the transaction mtid manually
 212  * to enforce sequencing.
 213  */
 214 hammer2_tid_t
 215 hammer2_trans_sub(hammer2_pfs_t *pmp)
 216 {
 217         hammer2_tid_t mtid;
 218
 219         mtid = atomic_fetchadd_64(&pmp->modify_tid, 1);
 220
 221         return (mtid);
 222 }
 223
 224 void
 225 hammer2_trans_setflags(hammer2_pfs_t *pmp, uint32_t flags)
 226 {
 227         atomic_set_int(&pmp->trans.flags, flags);
 228 }
 229
 230 /*
 231  * Typically used to clear trans flags asynchronously.  If TRANS_WAITING
 232  * is in the mask, and was previously set, this function will wake up
 233  * any waiters.
 234  */
 235 void
 236 hammer2_trans_clearflags(hammer2_pfs_t *pmp, uint32_t flags)
 237 {
 238         uint32_t oflags;
 239         uint32_t nflags;
 240
 241         for (;;) {
 242                 oflags = pmp->trans.flags;
 243                 cpu_ccfence();
 244                 nflags = oflags & ~flags;
 245                 if (atomic_cmpset_int(&pmp->trans.flags, oflags, nflags)) {
 246                         if ((oflags ^ nflags) & HAMMER2_TRANS_WAITING)
 247                                 wakeup(&pmp->trans.sync_wait);
 248                         break;
 249                 }
 250                 cpu_pause();
 251                 /* retry */
 252         }
 253 }
 254
 255 void
 256 hammer2_trans_done(hammer2_pfs_t *pmp, uint32_t flags)
 257 {
 258         uint32_t oflags;
 259         uint32_t nflags;
 260
 261 #if 0
 262         /*
 263          * Modifying ops on the front-end can cause dirty inodes to
 264          * build up in the sideq.  We don't flush these on inactive/reclaim
 265          * due to potential deadlocks, so we have to deal with them from
 266          * inside other nominal modifying front-end transactions.
 267          */
 268         if ((flags & HAMMER2_TRANS_SIDEQ) &&
 269             pmp->sideq_count > hammer2_limit_dirty_inodes / 2 &&
 270             pmp->sideq_count > (pmp->inum_count >> 3) &&
 271             pmp->mp) {
 272                 speedup_syncer(pmp->mp);
 273         }
 274 #endif
 275
 276         /*
 277          * Clean-up the transaction.  Wakeup any waiters when finishing
 278          * a flush transaction or transitioning the non-flush transaction
 279          * count from 2->1 while a flush transaction is pending.
 280          */
 281         for (;;) {
 282                 oflags = pmp->trans.flags;
 283                 cpu_ccfence();
 284                 KKASSERT(oflags & HAMMER2_TRANS_MASK);
 285
 286                 nflags = (oflags - 1) & ~flags;
 287                 if (flags & HAMMER2_TRANS_ISFLUSH) {
 288                         nflags &= ~HAMMER2_TRANS_WAITING;
 289                 }
 290                 if ((oflags & (HAMMER2_TRANS_ISFLUSH|HAMMER2_TRANS_MASK)) ==
 291                     (HAMMER2_TRANS_ISFLUSH|2)) {
 292                         nflags &= ~HAMMER2_TRANS_WAITING;
 293                 }
 294                 if (atomic_cmpset_int(&pmp->trans.flags, oflags, nflags)) {
 295                         if ((oflags ^ nflags) & HAMMER2_TRANS_WAITING)
 296                                 wakeup(&pmp->trans.sync_wait);
 297                         break;
 298                 }
 299                 cpu_pause();
 300                 /* retry */
 301         }
 302 }
 303
 304 /*
 305  * Obtain new, unique inode number (not serialized by caller).
 306  */
 307 hammer2_tid_t
 308 hammer2_trans_newinum(hammer2_pfs_t *pmp)
 309 {
 310         hammer2_tid_t tid;
 311
 312         tid = atomic_fetchadd_64(&pmp->inode_tid, 1);
 313
 314         return tid;
 315 }
 316
 317 /*
 318  * Assert that a strategy call is ok here.  Currently we allow strategy
 319  * calls in all situations, including during flushes.  Previously:
 320  *      (old) (1) In a normal transaction.
 321  */
 322 void
 323 hammer2_trans_assert_strategy(hammer2_pfs_t *pmp)
 324 {
 325 #if 0
 326         KKASSERT((pmp->trans.flags & HAMMER2_TRANS_ISFLUSH) == 0);
 327 #endif
 328 }
 329
 330 /*
 331  * Flush the chain and all modified sub-chains through the specified
 332  * synchronization point, propagating blockref updates back up.  As
 333  * part of this propagation, mirror_tid and inode/data usage statistics
 334  * propagates back upward.
 335  *
 336  * Returns a HAMMER2 error code, 0 if no error.  Note that I/O errors from
 337  * buffers dirtied during the flush operation can occur later.
 338  *
 339  * modify_tid (clc - cluster level change) is not propagated.
 340  *
 341  * update_tid (clc) is used for validation and is not propagated by this
 342  * function.
 343  *
 344  * This routine can be called from several places but the most important
 345  * is from VFS_SYNC (frontend) via hammer2_xop_inode_flush (backend).
 346  *
 347  * chain is locked on call and will remain locked on return.  The chain's
 348  * UPDATE flag indicates that its parent's block table (which is not yet
 349  * part of the flush) should be updated.
 350  *
 351  * flags:
 352  *      HAMMER2_FLUSH_TOP       Indicates that this is the top of the flush.
 353  *                              Is cleared for the recursion.
 354  *
 355  *      HAMMER2_FLUSH_ALL       Recurse everything
 356  *
 357  *      HAMMER2_FLUSH_INODE_STOP
 358  *                              Stop at PFS inode or normal inode boundary
 359  */
 360 int
 361 hammer2_flush(hammer2_chain_t *chain, int flags)
 362 {
 363         hammer2_flush_info_t info;
 364         int loops;
 365
 366         /*
 367          * Execute the recursive flush and handle deferrals.
 368          *
 369          * Chains can be ridiculously long (thousands deep), so to
 370          * avoid blowing out the kernel stack the recursive flush has a
 371          * depth limit.  Elements at the limit are placed on a list
 372          * for re-execution after the stack has been popped.
 373          */
 374         bzero(&info, sizeof(info));
 375         info.flags = flags & ~HAMMER2_FLUSH_TOP;
 376
 377         /*
 378          * Calculate parent (can be NULL), if not NULL the flush core
 379          * expects the parent to be referenced so it can easily lock/unlock
 380          * it without it getting ripped up.
 381          */
 382         if ((info.parent = chain->parent) != NULL)
 383                 hammer2_chain_ref(info.parent);
 384
 385         /*
 386          * Extra ref needed because flush_core expects it when replacing
 387          * chain.
 388          */
 389         hammer2_chain_ref(chain);
 390         loops = 0;
 391
 392         for (;;) {
 393                 /*
 394                  * [re]flush chain as the deep recursion may have generated
 395                  * additional modifications.
 396                  */
 397                 if (info.parent != chain->parent) {
 398                         if (hammer2_debug & 0x0040) {
 399                                 kprintf("LOST CHILD4 %p->%p "
 400                                         "(actual parent %p)\n",
 401                                         info.parent, chain, chain->parent);
 402                         }
 403                         hammer2_chain_drop(info.parent);
 404                         info.parent = chain->parent;
 405                         hammer2_chain_ref(info.parent);
 406                 }
 407                 if (hammer2_flush_core(&info, chain, flags) == 0)
 408                         break;
 409
 410                 if (++loops % 1000 == 0) {
 411                         kprintf("hammer2_flush: excessive loops on %p\n",
 412                                 chain);
 413                         if (hammer2_debug & 0x100000)
 414                                 Debugger("hell4");
 415                 }
 416         }
 417 #ifdef HAMMER2_SCAN_DEBUG
 418         if (info.scan_count >= 10)
 419         kprintf("hammer2_flush: scan_count %ld (%ld,%ld,%ld,%ld) "
 420                 "bt(%ld,%ld,%ld,%ld,%ld,%ld)\n",
 421                 info.scan_count,
 422                 info.scan_mod_count,
 423                 info.scan_upd_count,
 424                 info.scan_onf_count,
 425                 info.scan_del_count,
 426                 info.scan_btype[1],
 427                 info.scan_btype[2],
 428                 info.scan_btype[3],
 429                 info.scan_btype[4],
 430                 info.scan_btype[5],
 431                 info.scan_btype[6]);
 432 #endif
 433         hammer2_chain_drop(chain);
 434         if (info.parent)
 435                 hammer2_chain_drop(info.parent);
 436         return (info.error);
 437 }
 438
 439 /*
 440  * This is the core of the chain flushing code.  The chain is locked by the
 441  * caller and must also have an extra ref on it by the caller, and remains
 442  * locked and will have an extra ref on return.  info.parent is referenced
 443  * but not locked.
 444  *
 445  * Upon return, the caller can test the UPDATE bit on the chain to determine
 446  * if the parent needs updating.
 447  *
 448  * If non-zero is returned, the chain's parent changed during the flush and
 449  * the caller must retry the operation.
 450  *
 451  * (1) Determine if this node is a candidate for the flush, return if it is
 452  *     not.  fchain and vchain are always candidates for the flush.
 453  *
 454  * (2) If we recurse too deep the chain is entered onto the deferral list and
 455  *     the current flush stack is aborted until after the deferral list is
 456  *     run.
 457  *
 458  * (3) Recursively flush live children (rbtree).  This can create deferrals.
 459  *     A successful flush clears the MODIFIED and UPDATE bits on the children
 460  *     and typically causes the parent to be marked MODIFIED as the children
 461  *     update the parent's block table.  A parent might already be marked
 462  *     MODIFIED due to a deletion (whos blocktable update in the parent is
 463  *     handled by the frontend), or if the parent itself is modified by the
 464  *     frontend for other reasons.
 465  *
 466  * (4) Permanently disconnected sub-trees are cleaned up by the front-end.
 467  *     Deleted-but-open inodes can still be individually flushed via the
 468  *     filesystem syncer.
 469  *
 470  * (5) Delete parents on the way back up if they are normal indirect blocks
 471  *     and have no children.
 472  *
 473  * (6) Note that an unmodified child may still need the block table in its
 474  *     parent updated (e.g. rename/move).  The child will have UPDATE set
 475  *     in this case.
 476  *
 477  *                      WARNING ON BREF MODIFY_TID/MIRROR_TID
 478  *
 479  * blockref.modify_tid is consistent only within a PFS, and will not be
 480  * consistent during synchronization.  mirror_tid is consistent across the
 481  * block device regardless of the PFS.
 482  */
 483 static int
 484 hammer2_flush_core(hammer2_flush_info_t *info, hammer2_chain_t *chain,
 485                    int flags)
 486 {
 487         hammer2_chain_t *parent;
 488         hammer2_dev_t *hmp;
 489         int save_error;
 490         int retry;
 491
 492         retry = 0;
 493
 494         /*
 495          * (1) Optimize downward recursion to locate nodes needing action.
 496          *     Nothing to do if none of these flags are set.
 497          */
 498         if ((chain->flags & HAMMER2_CHAIN_FLUSH_MASK) == 0)
 499                 return 0;
 500
 501         hmp = chain->hmp;
 502
 503         /*
 504          * NOTE: parent can be NULL, usually due to destroy races.
 505          */
 506         parent = info->parent;
 507         KKASSERT(chain->parent == parent);
 508
 509         /*
 510          * Downward search recursion
 511          *
 512          * We must be careful on cold stops, which often occur on inode
 513          * boundaries due to the way hammer2_vfs_sync() sequences the flush.
 514          * Be sure to issue an appropriate chain_setflush()
 515          */
 516         if ((chain->flags & HAMMER2_CHAIN_PFSBOUNDARY) &&
 517             (flags & HAMMER2_FLUSH_ALL) == 0 &&
 518             (flags & HAMMER2_FLUSH_TOP) == 0 &&
 519             chain->pmp && chain->pmp->mp) {
 520                 /*
 521                  * If FLUSH_ALL is not specified the caller does not want
 522                  * to recurse through PFS roots that have been mounted.
 523                  *
 524                  * (If the PFS has not been mounted there may not be
 525                  *  anything monitoring its chains and its up to us
 526                  *  to flush it).
 527                  *
 528                  * The typical sequence is to flush dirty PFS's starting at
 529                  * their root downward, then flush the device root (vchain).
 530                  * It is this second flush that typically leaves out the
 531                  * ALL flag.
 532                  *
 533                  * However we must still process the PFSROOT chains for block
 534                  * table updates in their parent (which IS part of our flush).
 535                  *
 536                  * NOTE: The volume root, vchain, does not set PFSBOUNDARY.
 537                  *
 538                  * NOTE: We must re-set ONFLUSH in the parent to retain if
 539                  *       this chain (that we are skipping) requires work.
 540                  */
 541                 if (chain->flags & (HAMMER2_CHAIN_ONFLUSH |
 542                                     HAMMER2_CHAIN_DESTROY |
 543                                     HAMMER2_CHAIN_MODIFIED)) {
 544                         hammer2_chain_setflush(parent);
 545                 }
 546                 goto done;
 547         } else if (chain->bref.type == HAMMER2_BREF_TYPE_INODE &&
 548                    (flags & HAMMER2_FLUSH_INODE_STOP) &&
 549                    (flags & HAMMER2_FLUSH_ALL) == 0 &&
 550                    (flags & HAMMER2_FLUSH_TOP) == 0 &&
 551                    chain->pmp && chain->pmp->mp) {
 552                 /*
 553                  * When FLUSH_INODE_STOP is specified we are being asked not
 554                  * to include any inode changes for inodes we encounter,
 555                  * with the exception of the inode that the flush began with.
 556                  * So: INODE, INODE_STOP, and TOP==0 basically.
 557                  *
 558                  * Dirty inodes are flushed based on the hammer2_inode
 559                  * in-memory structure, issuing a chain_setflush() here
 560                  * will only cause unnecessary traversals of the topology.
 561                  */
 562                 goto done;
 563 #if 0
 564                 /*
 565                  * If FLUSH_INODE_STOP is specified and both ALL and TOP
 566                  * are clear, we must not flush the chain.  The chain should
 567                  * have already been flushed and any further ONFLUSH/UPDATE
 568                  * setting will be related to the next flush.
 569                  *
 570                  * This features allows us to flush inodes independently of
 571                  * each other and meta-data above the inodes separately.
 572                  */
 573                 if (chain->flags & (HAMMER2_CHAIN_ONFLUSH |
 574                                     HAMMER2_CHAIN_DESTROY |
 575                                     HAMMER2_CHAIN_MODIFIED)) {
 576                         if (parent)
 577                                 hammer2_chain_setflush(parent);
 578                 }
 579 #endif
 580         } else if (info->depth == HAMMER2_FLUSH_DEPTH_LIMIT) {
 581                 /*
 582                  * Recursion depth reached.
 583                  */
 584                 panic("hammer2: flush depth limit");
 585         } else if (chain->flags & (HAMMER2_CHAIN_ONFLUSH |
 586                                    HAMMER2_CHAIN_DESTROY)) {
 587                 /*
 588                  * Downward recursion search (actual flush occurs bottom-up).
 589                  * pre-clear ONFLUSH.  It can get set again due to races or
 590                  * flush errors, which we want so the scan finds us again in
 591                  * the next flush.
 592                  *
 593                  * We must also recurse if DESTROY is set so we can finally
 594                  * get rid of the related children, otherwise the node will
 595                  * just get re-flushed on lastdrop.
 596                  *
 597                  * WARNING!  The recursion will unlock/relock info->parent
 598                  *           (which is 'chain'), potentially allowing it
 599                  *           to be ripped up.
 600                  */
 601                 atomic_clear_int(&chain->flags, HAMMER2_CHAIN_ONFLUSH);
 602                 save_error = info->error;
 603                 info->error = 0;
 604                 info->parent = chain;
 605
 606                 /*
 607                  * We may have to do this twice to catch any indirect
 608                  * block maintenance that occurs.
 609                  */
 610                 hammer2_spin_ex(&chain->core.spin);
 611                 RB_SCAN(hammer2_chain_tree, &chain->core.rbtree,
 612                         NULL, hammer2_flush_recurse, info);
 613                 if (chain->flags & HAMMER2_CHAIN_ONFLUSH) {
 614                         atomic_clear_int(&chain->flags, HAMMER2_CHAIN_ONFLUSH);
 615                         RB_SCAN(hammer2_chain_tree, &chain->core.rbtree,
 616                                 NULL, hammer2_flush_recurse, info);
 617                 }
 618                 hammer2_spin_unex(&chain->core.spin);
 619                 info->parent = parent;
 620
 621                 /*
 622                  * Re-set the flush bits if the flush was incomplete or
 623                  * an error occurred.  If an error occurs it is typically
 624                  * an allocation error.  Errors do not cause deferrals.
 625                  */
 626                 if (info->error)
 627                         hammer2_chain_setflush(chain);
 628                 info->error |= save_error;
 629
 630                 /*
 631                  * If we lost the parent->chain association we have to
 632                  * stop processing this chain because it is no longer
 633                  * in this recursion.  If it moved, it will be handled
 634                  * by the ONFLUSH flag elsewhere.
 635                  */
 636                 if (chain->parent != parent) {
 637                         kprintf("LOST CHILD2 %p->%p (actual parent %p)\n",
 638                                 parent, chain, chain->parent);
 639                         goto done;
 640                 }
 641         }
 642
 643         /*
 644          * Now we are in the bottom-up part of the recursion.
 645          *
 646          * We continue to try to update the chain on lower-level errors, but
 647          * the flush code may decide not to flush the volume root.
 648          *
 649          * XXX should we continue to try to update the chain if an error
 650          *     occurred?
 651          */
 652
 653         /*
 654          * Both parent and chain must be locked in order to flush chain,
 655          * in order to properly update the parent under certain conditions.
 656          *
 657          * In addition, we can't safely unlock/relock the chain once we
 658          * start flushing the chain itself, which we would have to do later
 659          * on in order to lock the parent if we didn't do that now.
 660          */
 661         hammer2_chain_ref_hold(chain);
 662         hammer2_chain_unlock(chain);
 663         if (parent)
 664                 hammer2_chain_lock(parent, HAMMER2_RESOLVE_ALWAYS);
 665         hammer2_chain_lock(chain, HAMMER2_RESOLVE_MAYBE);
 666         hammer2_chain_drop_unhold(chain);
 667
 668         /*
 669          * Can't process if we can't access their content.
 670          */
 671         if ((parent && parent->error) || chain->error) {
 672                 kprintf("hammer2: chain error during flush\n");
 673                 info->error |= chain->error;
 674                 if (parent) {
 675                         info->error |= parent->error;
 676                         hammer2_chain_unlock(parent);
 677                 }
 678                 goto done;
 679         }
 680
 681         if (chain->parent != parent) {
 682                 if (hammer2_debug & 0x0040) {
 683                         kprintf("LOST CHILD3 %p->%p (actual parent %p)\n",
 684                                 parent, chain, chain->parent);
 685                 }
 686                 KKASSERT(parent != NULL);
 687                 hammer2_chain_unlock(parent);
 688                 retry = 1;
 689                 goto done;
 690         }
 691
 692         /*
 693          * Propagate the DESTROY flag downwards.  This dummies up the flush
 694          * code and tries to invalidate related buffer cache buffers to
 695          * avoid the disk write.
 696          */
 697         if (parent && (parent->flags & HAMMER2_CHAIN_DESTROY))
 698                 atomic_set_int(&chain->flags, HAMMER2_CHAIN_DESTROY);
 699
 700         /*
 701          * Dispose of the modified bit.
 702          *
 703          * If parent is present, the UPDATE bit should already be set.
 704          * UPDATE should already be set.
 705          * bref.mirror_tid should already be set.
 706          */
 707         if (chain->flags & HAMMER2_CHAIN_MODIFIED) {
 708                 KKASSERT((chain->flags & HAMMER2_CHAIN_UPDATE) ||
 709                          chain->parent == NULL);
 710                 atomic_clear_int(&chain->flags, HAMMER2_CHAIN_MODIFIED);
 711                 atomic_add_long(&hammer2_count_modified_chains, -1);
 712
 713                 /*
 714                  * Manage threads waiting for excessive dirty memory to
 715                  * be retired.
 716                  */
 717                 if (chain->pmp)
 718                         hammer2_pfs_memory_wakeup(chain->pmp, -1);
 719
 720 #if 0
 721                 if ((chain->flags & HAMMER2_CHAIN_UPDATE) == 0 &&
 722                     chain != &hmp->vchain &&
 723                     chain != &hmp->fchain) {
 724                         /*
 725                          * Set UPDATE bit indicating that the parent block
 726                          * table requires updating.
 727                          */
 728                         atomic_set_int(&chain->flags, HAMMER2_CHAIN_UPDATE);
 729                 }
 730 #endif
 731
 732                 /*
 733                  * Issue the flush.  This is indirect via the DIO.
 734                  *
 735                  * NOTE: A DELETED node that reaches this point must be
 736                  *       flushed for synchronization point consistency.
 737                  *
 738                  * NOTE: Even though MODIFIED was already set, the related DIO
 739                  *       might not be dirty due to a system buffer cache
 740                  *       flush and must be set dirty if we are going to make
 741                  *       further modifications to the buffer.  Chains with
 742                  *       embedded data don't need this.
 743                  */
 744                 if (hammer2_debug & 0x1000) {
 745                         kprintf("Flush %p.%d %016jx/%d data=%016jx\n",
 746                                 chain, chain->bref.type,
 747                                 (uintmax_t)chain->bref.key,
 748                                 chain->bref.keybits,
 749                                 (uintmax_t)chain->bref.data_off);
 750                 }
 751
 752                 /*
 753                  * Update chain CRCs for flush.
 754                  *
 755                  * NOTE: Volume headers are NOT flushed here as they require
 756                  *       special processing.
 757                  */
 758                 switch(chain->bref.type) {
 759                 case HAMMER2_BREF_TYPE_FREEMAP:
 760                         /*
 761                          * Update the volume header's freemap_tid to the
 762                          * freemap's flushing mirror_tid.
 763                          *
 764                          * (note: embedded data, do not call setdirty)
 765                          */
 766                         KKASSERT(hmp->vchain.flags & HAMMER2_CHAIN_MODIFIED);
 767                         KKASSERT(chain == &hmp->fchain);
 768                         hmp->voldata.freemap_tid = chain->bref.mirror_tid;
 769                         if (hammer2_debug & 0x8000) {
 770                                 /* debug only, avoid syslogd loop */
 771                                 kprintf("sync freemap mirror_tid %08jx\n",
 772                                         (intmax_t)chain->bref.mirror_tid);
 773                         }
 774
 775                         /*
 776                          * The freemap can be flushed independently of the
 777                          * main topology, but for the case where it is
 778                          * flushed in the same transaction, and flushed
 779                          * before vchain (a case we want to allow for
 780                          * performance reasons), make sure modifications
 781                          * made during the flush under vchain use a new
 782                          * transaction id.
 783                          *
 784                          * Otherwise the mount recovery code will get confused.
 785                          */
 786                         ++hmp->voldata.mirror_tid;
 787                         break;
 788                 case HAMMER2_BREF_TYPE_VOLUME:
 789                         /*
 790                          * The free block table is flushed by
 791                          * hammer2_vfs_sync() before it flushes vchain.
 792                          * We must still hold fchain locked while copying
 793                          * voldata to volsync, however.
 794                          *
 795                          * These do not error per-say since their data does
 796                          * not need to be re-read from media on lock.
 797                          *
 798                          * (note: embedded data, do not call setdirty)
 799                          */
 800                         hammer2_chain_lock(&hmp->fchain,
 801                                            HAMMER2_RESOLVE_ALWAYS);
 802                         hammer2_voldata_lock(hmp);
 803                         if (hammer2_debug & 0x8000) {
 804                                 /* debug only, avoid syslogd loop */
 805                                 kprintf("sync volume  mirror_tid %08jx\n",
 806                                         (intmax_t)chain->bref.mirror_tid);
 807                         }
 808
 809                         /*
 810                          * Update the volume header's mirror_tid to the
 811                          * main topology's flushing mirror_tid.  It is
 812                          * possible that voldata.mirror_tid is already
 813                          * beyond bref.mirror_tid due to the bump we made
 814                          * above in BREF_TYPE_FREEMAP.
 815                          */
 816                         if (hmp->voldata.mirror_tid < chain->bref.mirror_tid) {
 817                                 hmp->voldata.mirror_tid =
 818                                         chain->bref.mirror_tid;
 819                         }
 820
 821                         /*
 822                          * The volume header is flushed manually by the
 823                          * syncer, not here.  All we do here is adjust the
 824                          * crc's.
 825                          */
 826                         KKASSERT(chain->data != NULL);
 827                         KKASSERT(chain->dio == NULL);
 828
 829                         hmp->voldata.icrc_sects[HAMMER2_VOL_ICRC_SECT1]=
 830                                 hammer2_icrc32(
 831                                         (char *)&hmp->voldata +
 832                                          HAMMER2_VOLUME_ICRC1_OFF,
 833                                         HAMMER2_VOLUME_ICRC1_SIZE);
 834                         hmp->voldata.icrc_sects[HAMMER2_VOL_ICRC_SECT0]=
 835                                 hammer2_icrc32(
 836                                         (char *)&hmp->voldata +
 837                                          HAMMER2_VOLUME_ICRC0_OFF,
 838                                         HAMMER2_VOLUME_ICRC0_SIZE);
 839                         hmp->voldata.icrc_volheader =
 840                                 hammer2_icrc32(
 841                                         (char *)&hmp->voldata +
 842                                          HAMMER2_VOLUME_ICRCVH_OFF,
 843                                         HAMMER2_VOLUME_ICRCVH_SIZE);
 844
 845                         if (hammer2_debug & 0x8000) {
 846                                 /* debug only, avoid syslogd loop */
 847                                 kprintf("syncvolhdr %016jx %016jx\n",
 848                                         hmp->voldata.mirror_tid,
 849                                         hmp->vchain.bref.mirror_tid);
 850                         }
 851                         hmp->volsync = hmp->voldata;
 852                         atomic_set_int(&chain->flags, HAMMER2_CHAIN_VOLUMESYNC);
 853                         hammer2_voldata_unlock(hmp);
 854                         hammer2_chain_unlock(&hmp->fchain);
 855                         break;
 856                 case HAMMER2_BREF_TYPE_DATA:
 857                         /*
 858                          * Data elements have already been flushed via the
 859                          * logical file buffer cache.  Their hash was set in
 860                          * the bref by the vop_write code.  Do not re-dirty.
 861                          *
 862                          * Make sure any device buffer(s) have been flushed
 863                          * out here (there aren't usually any to flush) XXX.
 864                          */
 865                         break;
 866                 case HAMMER2_BREF_TYPE_INDIRECT:
 867                 case HAMMER2_BREF_TYPE_FREEMAP_NODE:
 868                 case HAMMER2_BREF_TYPE_FREEMAP_LEAF:
 869                         /*
 870                          * Buffer I/O will be cleaned up when the volume is
 871                          * flushed (but the kernel is free to flush it before
 872                          * then, as well).
 873                          */
 874                         hammer2_chain_setcheck(chain, chain->data);
 875                         break;
 876                 case HAMMER2_BREF_TYPE_DIRENT:
 877                         /*
 878                          * A directory entry can use the check area to store
 879                          * the filename for filenames <= 64 bytes, don't blow
 880                          * it up!
 881                          */
 882                         if (chain->bytes)
 883                                 hammer2_chain_setcheck(chain, chain->data);
 884                         break;
 885                 case HAMMER2_BREF_TYPE_INODE:
 886                         /*
 887                          * NOTE: We must call io_setdirty() to make any late
 888                          *       changes to the inode data, the system might
 889                          *       have already flushed the buffer.
 890                          */
 891                         if (chain->data->ipdata.meta.op_flags &
 892                             HAMMER2_OPFLAG_PFSROOT) {
 893                                 /*
 894                                  * non-NULL pmp if mounted as a PFS.  We must
 895                                  * sync fields cached in the pmp? XXX
 896                                  */
 897                                 hammer2_inode_data_t *ipdata;
 898
 899                                 hammer2_io_setdirty(chain->dio);
 900                                 ipdata = &chain->data->ipdata;
 901                                 if (chain->pmp) {
 902                                         ipdata->meta.pfs_inum =
 903                                                 chain->pmp->inode_tid;
 904                                 }
 905                         } else {
 906                                 /* can't be mounted as a PFS */
 907                         }
 908
 909                         hammer2_chain_setcheck(chain, chain->data);
 910                         break;
 911                 default:
 912                         panic("hammer2_flush_core: unsupported "
 913                               "embedded bref %d",
 914                               chain->bref.type);
 915                         /* NOT REACHED */
 916                 }
 917
 918                 /*
 919                  * If the chain was destroyed try to avoid unnecessary I/O
 920                  * that might not have yet occurred.  Remove the data range
 921                  * from dedup candidacy and attempt to invalidation that
 922                  * potentially dirty portion of the I/O buffer.
 923                  */
 924                 if (chain->flags & HAMMER2_CHAIN_DESTROY) {
 925                         hammer2_io_dedup_delete(hmp,
 926                                                 chain->bref.type,
 927                                                 chain->bref.data_off,
 928                                                 chain->bytes);
 929 #if 0
 930                         hammer2_io_t *dio;
 931                         if (chain->dio) {
 932                                 hammer2_io_inval(chain->dio,
 933                                                  chain->bref.data_off,
 934                                                  chain->bytes);
 935                         } else if ((dio = hammer2_io_getquick(hmp,
 936                                                   chain->bref.data_off,
 937                                                   chain->bytes,
 938                                                   1)) != NULL) {
 939                                 hammer2_io_inval(dio,
 940                                                  chain->bref.data_off,
 941                                                  chain->bytes);
 942                                 hammer2_io_putblk(&dio);
 943                         }
 944 #endif
 945                 }
 946         }
 947
 948         /*
 949          * If UPDATE is set the parent block table may need to be updated.
 950          * This can fail if the hammer2_chain_modify() fails.
 951          *
 952          * NOTE: UPDATE may be set on vchain or fchain in which case
 953          *       parent could be NULL, or on an inode that has not yet
 954          *       been inserted into the radix tree.  It's easiest to allow
 955          *       the case and test for NULL.  parent can also wind up being
 956          *       NULL due to a deletion so we need to handle the case anyway.
 957          *
 958          * NOTE: UPDATE can be set when chains are renamed into or out of
 959          *       an indirect block, without the chain itself being flagged
 960          *       MODIFIED.
 961          *
 962          * If no parent exists we can just clear the UPDATE bit.  If the
 963          * chain gets reattached later on the bit will simply get set
 964          * again.
 965          */
 966         if ((chain->flags & HAMMER2_CHAIN_UPDATE) && parent == NULL)
 967                 atomic_clear_int(&chain->flags, HAMMER2_CHAIN_UPDATE);
 968
 969         /*
 970          * When flushing an inode outside of a FLUSH_FSSYNC we must NOT
 971          * update the parent block table to point at the flushed inode.
 972          * The block table should only ever be updated by the filesystem
 973          * sync code.  If we do, inode<->inode dependencies (such as
 974          * directory entries vs inode nlink count) can wind up not being
 975          * flushed together and result in a broken topology if a crash/reboot
 976          * occurs at the wrong time.
 977          */
 978         if (chain->bref.type == HAMMER2_BREF_TYPE_INODE &&
 979             (flags & HAMMER2_FLUSH_INODE_STOP) &&
 980             (flags & HAMMER2_FLUSH_FSSYNC) == 0 &&
 981             (flags & HAMMER2_FLUSH_ALL) == 0 &&
 982             chain->pmp && chain->pmp->mp) {
 983 #ifdef HAMMER2_DEBUG_SYNC
 984                 kprintf("inum %ld do not update parent, non-fssync\n",
 985                         (long)chain->bref.key);
 986 #endif
 987                 goto skipupdate;
 988         }
 989 #ifdef HAMMER2_DEBUG_SYNC
 990         if (chain->bref.type == HAMMER2_BREF_TYPE_INODE)
 991                 kprintf("inum %ld update parent\n", (long)chain->bref.key);
 992 #endif
 993
 994         /*
 995          * The chain may need its blockrefs updated in the parent, normal
 996          * path.
 997          */
 998         if (chain->flags & HAMMER2_CHAIN_UPDATE) {
 999                 hammer2_blockref_t *base;
1000                 int count;
1001
1002                 /*
1003                  * Clear UPDATE flag, mark parent modified, update its
1004                  * modify_tid if necessary, and adjust the parent blockmap.
1005                  */
1006                 atomic_clear_int(&chain->flags, HAMMER2_CHAIN_UPDATE);
1007
1008                 /*
1009                  * (optional code)
1010                  *
1011                  * Avoid actually modifying and updating the parent if it
1012                  * was flagged for destruction.  This can greatly reduce
1013                  * disk I/O in large tree removals because the
1014                  * hammer2_io_setinval() call in the upward recursion
1015                  * (see MODIFIED code above) can only handle a few cases.
1016                  */
1017                 if (parent->flags & HAMMER2_CHAIN_DESTROY) {
1018                         if (parent->bref.modify_tid < chain->bref.modify_tid) {
1019                                 parent->bref.modify_tid =
1020                                         chain->bref.modify_tid;
1021                         }
1022                         atomic_clear_int(&chain->flags, HAMMER2_CHAIN_BLKMAPPED |
1023                                                         HAMMER2_CHAIN_BLKMAPUPD);
1024                         goto skipupdate;
1025                 }
1026
1027                 /*
1028                  * The flusher is responsible for deleting empty indirect
1029                  * blocks at this point.  If we don't do this, no major harm
1030                  * will be done but the empty indirect blocks will stay in
1031                  * the topology and make it a messy and inefficient.
1032                  *
1033                  * The flusher is also responsible for collapsing the
1034                  * content of an indirect block into its parent whenever
1035                  * possible (with some hysteresis).  Not doing this will also
1036                  * not harm the topology, but would make it messy and
1037                  * inefficient.
1038                  */
1039                 if (chain->bref.type == HAMMER2_BREF_TYPE_INDIRECT) {
1040                         if (hammer2_chain_indirect_maintenance(parent, chain))
1041                                 goto skipupdate;
1042                 }
1043
1044                 /*
1045                  * We are updating the parent's blockmap, the parent must
1046                  * be set modified.  If this fails we re-set the UPDATE flag
1047                  * in the child.
1048                  *
1049                  * NOTE! A modification error can be ENOSPC.  We still want
1050                  *       to flush modified chains recursively, not break out,
1051                  *       so we just skip the update in this situation and
1052                  *       continue.  That is, we still need to try to clean
1053                  *       out dirty chains and buffers.
1054                  *
1055                  *       This may not help bulkfree though. XXX
1056                  */
1057                 save_error = hammer2_chain_modify(parent, 0, 0, 0);
1058                 if (save_error) {
1059                         info->error |= save_error;
1060                         kprintf("hammer2_flush: %016jx.%02x error=%08x\n",
1061                                 parent->bref.data_off, parent->bref.type,
1062                                 save_error);
1063                         atomic_set_int(&chain->flags, HAMMER2_CHAIN_UPDATE);
1064                         goto skipupdate;
1065                 }
1066                 if (parent->bref.modify_tid < chain->bref.modify_tid)
1067                         parent->bref.modify_tid = chain->bref.modify_tid;
1068
1069                 /*
1070                  * Calculate blockmap pointer
1071                  */
1072                 switch(parent->bref.type) {
1073                 case HAMMER2_BREF_TYPE_INODE:
1074                         /*
1075                          * Access the inode's block array.  However, there is
1076                          * no block array if the inode is flagged DIRECTDATA.
1077                          */
1078                         if (parent->data &&
1079                             (parent->data->ipdata.meta.op_flags &
1080                              HAMMER2_OPFLAG_DIRECTDATA) == 0) {
1081                                 base = &parent->data->
1082                                         ipdata.u.blockset.blockref[0];
1083                         } else {
1084                                 base = NULL;
1085                         }
1086                         count = HAMMER2_SET_COUNT;
1087                         break;
1088                 case HAMMER2_BREF_TYPE_INDIRECT:
1089                 case HAMMER2_BREF_TYPE_FREEMAP_NODE:
1090                         if (parent->data)
1091                                 base = &parent->data->npdata[0];
1092                         else
1093                                 base = NULL;
1094                         count = parent->bytes / sizeof(hammer2_blockref_t);
1095                         break;
1096                 case HAMMER2_BREF_TYPE_VOLUME:
1097                         base = &chain->hmp->voldata.sroot_blockset.blockref[0];
1098                         count = HAMMER2_SET_COUNT;
1099                         break;
1100                 case HAMMER2_BREF_TYPE_FREEMAP:
1101                         base = &parent->data->npdata[0];
1102                         count = HAMMER2_SET_COUNT;
1103                         break;
1104                 default:
1105                         base = NULL;
1106                         count = 0;
1107                         panic("hammer2_flush_core: "
1108                               "unrecognized blockref type: %d",
1109                               parent->bref.type);
1110                         break;
1111                 }
1112
1113                 /*
1114                  * Blocktable updates
1115                  *
1116                  * We synchronize pending statistics at this time.  Delta
1117                  * adjustments designated for the current and upper level
1118                  * are synchronized.
1119                  */
1120                 if (base && (chain->flags & HAMMER2_CHAIN_BLKMAPUPD)) {
1121                         if (chain->flags & HAMMER2_CHAIN_BLKMAPPED) {
1122                                 hammer2_spin_ex(&parent->core.spin);
1123                                 hammer2_base_delete(parent, base, count, chain,
1124                                                     NULL);
1125                                 hammer2_spin_unex(&parent->core.spin);
1126                                 /* base_delete clears both bits */
1127                         } else {
1128                                 atomic_clear_int(&chain->flags,
1129                                                  HAMMER2_CHAIN_BLKMAPUPD);
1130                         }
1131                 }
1132                 if (base && (chain->flags & HAMMER2_CHAIN_BLKMAPPED) == 0) {
1133                         hammer2_spin_ex(&parent->core.spin);
1134                         hammer2_base_insert(parent, base, count,
1135                                             chain, &chain->bref);
1136                         hammer2_spin_unex(&parent->core.spin);
1137                         /* base_insert sets BLKMAPPED */
1138                 }
1139         }
1140 skipupdate:
1141         if (parent)
1142                 hammer2_chain_unlock(parent);
1143
1144         /*
1145          * Final cleanup after flush
1146          */
1147 done:
1148         KKASSERT(chain->refs > 0);
1149
1150         return retry;
1151 }
1152
1153 /*
1154  * Flush recursion helper, called from flush_core, calls flush_core.
1155  *
1156  * Flushes the children of the caller's chain (info->parent), restricted
1157  * by sync_tid.
1158  *
1159  * This function may set info->error as a side effect.
1160  *
1161  * WARNING! If we do not call hammer2_flush_core() we must update
1162  *          bref.mirror_tid ourselves to indicate that the flush has
1163  *          processed the child.
1164  *
1165  * WARNING! parent->core spinlock is held on entry and return.
1166  */
1167 static int
1168 hammer2_flush_recurse(hammer2_chain_t *child, void *data)
1169 {
1170         hammer2_flush_info_t *info = data;
1171         hammer2_chain_t *parent = info->parent;
1172
1173 #ifdef HAMMER2_SCAN_DEBUG
1174         ++info->scan_count;
1175         if (child->flags & HAMMER2_CHAIN_MODIFIED)
1176                 ++info->scan_mod_count;
1177         if (child->flags & HAMMER2_CHAIN_UPDATE)
1178                 ++info->scan_upd_count;
1179         if (child->flags & HAMMER2_CHAIN_ONFLUSH)
1180                 ++info->scan_onf_count;
1181 #endif
1182
1183         /*
1184          * (child can never be fchain or vchain so a special check isn't
1185          *  needed).
1186          *
1187          * We must ref the child before unlocking the spinlock.
1188          *
1189          * The caller has added a ref to the parent so we can temporarily
1190          * unlock it in order to lock the child.  However, if it no longer
1191          * winds up being the child of the parent we must skip this child.
1192          *
1193          * NOTE! chain locking errors are fatal.  They are never out-of-space
1194          *       errors.
1195          */
1196         hammer2_chain_ref(child);
1197         hammer2_spin_unex(&parent->core.spin);
1198
1199         hammer2_chain_ref_hold(parent);
1200         hammer2_chain_unlock(parent);
1201         hammer2_chain_lock(child, HAMMER2_RESOLVE_MAYBE);
1202         if (child->parent != parent) {
1203                 kprintf("LOST CHILD1 %p->%p (actual parent %p)\n",
1204                         parent, child, child->parent);
1205                 goto done;
1206         }
1207         if (child->error) {
1208                 kprintf("CHILD ERROR DURING FLUSH LOCK %p->%p\n",
1209                         parent, child);
1210                 info->error |= child->error;
1211                 goto done;
1212         }
1213
1214         /*
1215          * Must propagate the DESTROY flag downwards, otherwise the
1216          * parent could end up never being removed because it will
1217          * be requeued to the flusher if it survives this run due to
1218          * the flag.
1219          */
1220         if (parent && (parent->flags & HAMMER2_CHAIN_DESTROY))
1221                 atomic_set_int(&child->flags, HAMMER2_CHAIN_DESTROY);
1222 #ifdef HAMMER2_SCAN_DEBUG
1223         if (child->flags & HAMMER2_CHAIN_DESTROY)
1224                 ++info->scan_del_count;
1225 #endif
1226         /*
1227          * Special handling of the root inode.  Because the root inode
1228          * contains an index of all the inodes in the PFS in addition to
1229          * its normal directory entries, any flush that is not part of a
1230          * filesystem sync must only flush the directory entries, and not
1231          * anything else.
1232          *
1233          * The child might be an indirect block, but H2 guarantees that
1234          * the key-range will fully partition the inode index from the
1235          * directory entries so the case just works naturally.
1236          */
1237         if ((parent->bref.flags & HAMMER2_BREF_FLAG_PFSROOT) &&
1238             (child->flags & HAMMER2_CHAIN_DESTROY) == 0 &&
1239             parent->bref.type == HAMMER2_BREF_TYPE_INODE &&
1240             (info->flags & HAMMER2_FLUSH_FSSYNC) == 0) {
1241                 if ((child->bref.key & HAMMER2_DIRHASH_VISIBLE) == 0) {
1242                         if (child->flags & HAMMER2_CHAIN_FLUSH_MASK) {
1243                                 hammer2_chain_setflush(parent);
1244                         }
1245                         goto done;
1246                 }
1247         }
1248
1249         /*
1250          * Recurse and collect deferral data.  We're in the media flush,
1251          * this can cross PFS boundaries.
1252          */
1253         if (child->flags & HAMMER2_CHAIN_FLUSH_MASK) {
1254 #ifdef HAMMER2_SCAN_DEBUG
1255                 if (child->bref.type < 7)
1256                         ++info->scan_btype[child->bref.type];
1257 #endif
1258                 ++info->depth;
1259                 hammer2_flush_core(info, child, info->flags);
1260                 --info->depth;
1261         }
1262
1263 done:
1264         /*
1265          * Relock to continue the loop.
1266          */
1267         hammer2_chain_unlock(child);
1268         hammer2_chain_lock(parent, HAMMER2_RESOLVE_MAYBE);
1269         hammer2_chain_drop_unhold(parent);
1270         if (parent->error) {
1271                 kprintf("PARENT ERROR DURING FLUSH LOCK %p->%p\n",
1272                         parent, child);
1273                 info->error |= parent->error;
1274         }
1275         hammer2_chain_drop(child);
1276         KKASSERT(info->parent == parent);
1277         hammer2_spin_ex(&parent->core.spin);
1278
1279         return (0);
1280 }
1281
1282 /*
1283  * flush helper (backend threaded)
1284  *
1285  * Flushes chain topology for the specified inode.
1286  *
1287  * HAMMER2_XOP_INODE_STOP       The flush recursion stops at inode boundaries.
1288  *                              Inodes belonging to the same flush are flushed
1289  *                              separately.
1290  *
1291  * chain->parent can be NULL, usually due to destroy races or detached inodes.
1292  *
1293  * Primarily called from vfs_sync().
1294  */
1295 void
1296 hammer2_xop_inode_flush(hammer2_xop_t *arg, void *scratch __unused, int clindex)
1297 {
1298         hammer2_xop_flush_t *xop = &arg->xop_flush;
1299         hammer2_chain_t *chain;
1300         hammer2_inode_t *ip;
1301         hammer2_dev_t *hmp;
1302         hammer2_pfs_t *pmp;
1303         hammer2_devvp_t *e;
1304         struct vnode *devvp;
1305         int flush_error = 0;
1306         int fsync_error = 0;
1307         int total_error = 0;
1308         int j;
1309         int xflags;
1310         int ispfsroot = 0;
1311
1312         xflags = HAMMER2_FLUSH_TOP;
1313         if (xop->head.flags & HAMMER2_XOP_INODE_STOP)
1314                 xflags |= HAMMER2_FLUSH_INODE_STOP;
1315         if (xop->head.flags & HAMMER2_XOP_FSSYNC)
1316                 xflags |= HAMMER2_FLUSH_FSSYNC;
1317
1318         /*
1319          * Flush core chains
1320          */
1321         ip = xop->head.ip1;
1322         pmp = ip->pmp;
1323         chain = hammer2_inode_chain(ip, clindex, HAMMER2_RESOLVE_ALWAYS);
1324         if (chain) {
1325                 hmp = chain->hmp;
1326                 if (chain->flags & HAMMER2_CHAIN_FLUSH_MASK) {
1327                         /*
1328                          * Due to flush partitioning the chain topology
1329                          * above the inode's chain may no longer be flagged.
1330                          * When asked to flush an inode, remark the topology
1331                          * leading to that inode.
1332                          */
1333                         if (chain->parent)
1334                                 hammer2_chain_setflush(chain->parent);
1335                         hammer2_flush(chain, xflags);
1336
1337                         /* XXX cluster */
1338                         if (ip == pmp->iroot && pmp != hmp->spmp) {
1339                                 hammer2_spin_ex(&pmp->inum_spin);
1340                                 pmp->pfs_iroot_blocksets[clindex] =
1341                                         chain->data->ipdata.u.blockset;
1342                                 hammer2_spin_unex(&pmp->inum_spin);
1343                         }
1344
1345 #if 0
1346                         /*
1347                          * Propogate upwards but only cross an inode boundary
1348                          * for inodes associated with the current filesystem
1349                          * sync.
1350                          */
1351                         if ((xop->head.flags & HAMMER2_XOP_PARENTONFLUSH) ||
1352                             chain->bref.type != HAMMER2_BREF_TYPE_INODE) {
1353                                 parent = chain->parent;
1354                                 if (parent)
1355                                         hammer2_chain_setflush(parent);
1356                         }
1357 #endif
1358                 }
1359                 if (chain->flags & HAMMER2_CHAIN_PFSBOUNDARY)
1360                         ispfsroot = 1;
1361                 hammer2_chain_unlock(chain);
1362                 hammer2_chain_drop(chain);
1363                 chain = NULL;
1364         } else {
1365                 hmp = NULL;
1366         }
1367
1368         /*
1369          * Only flush the volume header if asked to, plus the inode must also
1370          * be the PFS root.
1371          */
1372         if ((xop->head.flags & HAMMER2_XOP_VOLHDR) == 0)
1373                 goto skip;
1374         if (ispfsroot == 0)
1375                 goto skip;
1376
1377         /*
1378          * Flush volume roots.  Avoid replication, we only want to
1379          * flush each hammer2_dev (hmp) once.
1380          */
1381         for (j = clindex - 1; j >= 0; --j) {
1382                 if ((chain = ip->cluster.array[j].chain) != NULL) {
1383                         if (chain->hmp == hmp) {
1384                                 chain = NULL;   /* safety */
1385                                 goto skip;
1386                         }
1387                 }
1388         }
1389         chain = NULL;   /* safety */
1390
1391         /*
1392          * spmp transaction.  The super-root is never directly mounted so
1393          * there shouldn't be any vnodes, let alone any dirty vnodes
1394          * associated with it, so we shouldn't have to mess around with any
1395          * vnode flushes here.
1396          */
1397         hammer2_trans_init(hmp->spmp, HAMMER2_TRANS_ISFLUSH);
1398
1399         /*
1400          * We must flush the superroot down to the PFS iroot.  Remember
1401          * that hammer2_chain_setflush() stops at inode boundaries, so
1402          * the pmp->iroot has been flushed and flagged down to the superroot,
1403          * but the volume root (vchain) probably has not yet been flagged.
1404          */
1405         if (hmp->spmp->iroot) {
1406                 chain = hmp->spmp->iroot->cluster.array[0].chain;
1407                 if (chain) {
1408                         hammer2_chain_ref(chain);
1409                         hammer2_chain_lock(chain, HAMMER2_RESOLVE_ALWAYS);
1410                         flush_error |=
1411                                 hammer2_flush(chain,
1412                                               HAMMER2_FLUSH_TOP |
1413                                               HAMMER2_FLUSH_INODE_STOP |
1414                                               HAMMER2_FLUSH_FSSYNC);
1415                         hammer2_chain_unlock(chain);
1416                         hammer2_chain_drop(chain);
1417                 }
1418         }
1419
1420         /*
1421          * Media mounts have two 'roots', vchain for the topology
1422          * and fchain for the free block table.  Flush both.
1423          *
1424          * Note that the topology and free block table are handled
1425          * independently, so the free block table can wind up being
1426          * ahead of the topology.  We depend on the bulk free scan
1427          * code to deal with any loose ends.
1428          *
1429          * vchain and fchain do not error on-lock since their data does
1430          * not have to be re-read from media.
1431          */
1432         hammer2_chain_ref(&hmp->vchain);
1433         hammer2_chain_lock(&hmp->vchain, HAMMER2_RESOLVE_ALWAYS);
1434         hammer2_chain_ref(&hmp->fchain);
1435         hammer2_chain_lock(&hmp->fchain, HAMMER2_RESOLVE_ALWAYS);
1436         if (hmp->fchain.flags & HAMMER2_CHAIN_FLUSH_MASK) {
1437                 /*
1438                  * This will also modify vchain as a side effect,
1439                  * mark vchain as modified now.
1440                  */
1441                 hammer2_voldata_modify(hmp);
1442                 chain = &hmp->fchain;
1443                 flush_error |= hammer2_flush(chain, HAMMER2_FLUSH_TOP);
1444                 KKASSERT(chain == &hmp->fchain);
1445         }
1446         hammer2_chain_unlock(&hmp->fchain);
1447         hammer2_chain_unlock(&hmp->vchain);
1448         hammer2_chain_drop(&hmp->fchain);
1449         /* vchain dropped down below */
1450
1451         hammer2_chain_lock(&hmp->vchain, HAMMER2_RESOLVE_ALWAYS);
1452         if (hmp->vchain.flags & HAMMER2_CHAIN_FLUSH_MASK) {
1453                 chain = &hmp->vchain;
1454                 flush_error |= hammer2_flush(chain, HAMMER2_FLUSH_TOP);
1455                 KKASSERT(chain == &hmp->vchain);
1456         }
1457         hammer2_chain_unlock(&hmp->vchain);
1458         hammer2_chain_drop(&hmp->vchain);
1459
1460         /*
1461          * We can't safely flush the volume header until we have
1462          * flushed any device buffers which have built up.
1463          *
1464          * XXX this isn't being incremental
1465          */
1466         TAILQ_FOREACH(e, &hmp->devvpl, entry) {
1467                 devvp = e->devvp;
1468                 KKASSERT(devvp);
1469                 vn_lock(devvp, LK_EXCLUSIVE | LK_RETRY);
1470                 fsync_error = VOP_FSYNC(devvp, MNT_WAIT, 0);
1471                 vn_unlock(devvp);
1472                 if (fsync_error || flush_error) {
1473                         kprintf("hammer2: sync error fsync=%d h2flush=0x%04x dev=%s\n",
1474                                 fsync_error, flush_error, e->path);
1475                 }
1476         }
1477
1478         /*
1479          * The flush code sets CHAIN_VOLUMESYNC to indicate that the
1480          * volume header needs synchronization via hmp->volsync.
1481          *
1482          * XXX synchronize the flag & data with only this flush XXX
1483          */
1484         if (fsync_error == 0 && flush_error == 0 &&
1485             (hmp->vchain.flags & HAMMER2_CHAIN_VOLUMESYNC)) {
1486                 struct buf *bp;
1487                 int vol_error = 0;
1488
1489                 /*
1490                  * Synchronize the disk before flushing the volume
1491                  * header.
1492                  */
1493                 bp = getpbuf(NULL);
1494                 bp->b_bio1.bio_offset = 0;
1495                 bp->b_bufsize = 0;
1496                 bp->b_bcount = 0;
1497                 bp->b_cmd = BUF_CMD_FLUSH;
1498                 bp->b_bio1.bio_done = biodone_sync;
1499                 bp->b_bio1.bio_flags |= BIO_SYNC;
1500                 vn_strategy(hmp->devvp, &bp->b_bio1);
1501                 fsync_error = biowait(&bp->b_bio1, "h2vol");
1502                 relpbuf(bp, NULL);
1503
1504                 /*
1505                  * Then we can safely flush the version of the
1506                  * volume header synchronized by the flush code.
1507                  */
1508                 j = hmp->volhdrno + 1;
1509                 if (j < 0)
1510                         j = 0;
1511                 if (j >= HAMMER2_NUM_VOLHDRS)
1512                         j = 0;
1513                 if (j * HAMMER2_ZONE_BYTES64 + HAMMER2_SEGSIZE >
1514                     hmp->volsync.volu_size) {
1515                         j = 0;
1516                 }
1517                 if (hammer2_debug & 0x8000) {
1518                         /* debug only, avoid syslogd loop */
1519                         kprintf("sync volhdr %d %jd\n",
1520                                 j, (intmax_t)hmp->volsync.volu_size);
1521                 }
1522                 bp = getblk(hmp->devvp, j * HAMMER2_ZONE_BYTES64,
1523                             HAMMER2_PBUFSIZE, GETBLK_KVABIO, 0);
1524                 atomic_clear_int(&hmp->vchain.flags,
1525                                  HAMMER2_CHAIN_VOLUMESYNC);
1526                 bkvasync(bp);
1527                 bcopy(&hmp->volsync, bp->b_data, HAMMER2_PBUFSIZE);
1528                 vol_error = bwrite(bp);
1529                 hmp->volhdrno = j;
1530                 if (vol_error)
1531                         fsync_error = vol_error;
1532         }
1533         if (flush_error)
1534                 total_error = flush_error;
1535         if (fsync_error)
1536                 total_error = hammer2_errno_to_error(fsync_error);
1537
1538         /* spmp trans */
1539         hammer2_trans_done(hmp->spmp, HAMMER2_TRANS_ISFLUSH);
1540 skip:
1541         hammer2_xop_feed(&xop->head, NULL, clindex, total_error);
1542 }