sys/vfs/hammer/hammer_ondisk.c

   1 /*
   2  * Copyright (c) 2007 The DragonFly Project.  All rights reserved.
   3  *
   4  * This code is derived from software contributed to The DragonFly Project
   5  * by Matthew Dillon <dillon@backplane.com>
   6  *
   7  * Redistribution and use in source and binary forms, with or without
   8  * modification, are permitted provided that the following conditions
   9  * are met:
  10  *
  11  * 1. Redistributions of source code must retain the above copyright
  12  *    notice, this list of conditions and the following disclaimer.
  13  * 2. Redistributions in binary form must reproduce the above copyright
  14  *    notice, this list of conditions and the following disclaimer in
  15  *    the documentation and/or other materials provided with the
  16  *    distribution.
  17  * 3. Neither the name of The DragonFly Project nor the names of its
  18  *    contributors may be used to endorse or promote products derived
  19  *    from this software without specific, prior written permission.
  20  *
  21  * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
  22  * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
  23  * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
  24  * FOR A PARTICULAR PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE
  25  * COPYRIGHT HOLDERS OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
  26  * INCIDENTAL, SPECIAL, EXEMPLARY OR CONSEQUENTIAL DAMAGES (INCLUDING,
  27  * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
  28  * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
  29  * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
  30  * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
  31  * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  32  * SUCH DAMAGE.
  33  *
  34  * $DragonFly: src/sys/vfs/hammer/hammer_ondisk.c,v 1.35 2008/03/24 23:50:23 dillon Exp $
  35  */
  36 /*
  37  * Manage HAMMER's on-disk structures.  These routines are primarily
  38  * responsible for interfacing with the kernel's I/O subsystem and for
  39  * managing in-memory structures.
  40  */
  41
  42 #include "hammer.h"
  43 #include <sys/fcntl.h>
  44 #include <sys/nlookup.h>
  45 #include <sys/buf.h>
  46 #include <sys/buf2.h>
  47
  48 static void hammer_free_volume(hammer_volume_t volume);
  49 static int hammer_load_volume(hammer_volume_t volume);
  50 static int hammer_load_buffer(hammer_buffer_t buffer, int isnew);
  51 static int hammer_load_node(hammer_node_t node);
  52
  53 /*
  54  * Red-Black tree support for various structures
  55  */
  56 static int
  57 hammer_ino_rb_compare(hammer_inode_t ip1, hammer_inode_t ip2)
  58 {
  59         if (ip1->obj_id < ip2->obj_id)
  60                 return(-1);
  61         if (ip1->obj_id > ip2->obj_id)
  62                 return(1);
  63         if (ip1->obj_asof < ip2->obj_asof)
  64                 return(-1);
  65         if (ip1->obj_asof > ip2->obj_asof)
  66                 return(1);
  67         return(0);
  68 }
  69
  70 static int
  71 hammer_inode_info_cmp(hammer_inode_info_t info, hammer_inode_t ip)
  72 {
  73         if (info->obj_id < ip->obj_id)
  74                 return(-1);
  75         if (info->obj_id > ip->obj_id)
  76                 return(1);
  77         if (info->obj_asof < ip->obj_asof)
  78                 return(-1);
  79         if (info->obj_asof > ip->obj_asof)
  80                 return(1);
  81         return(0);
  82 }
  83
  84 static int
  85 hammer_vol_rb_compare(hammer_volume_t vol1, hammer_volume_t vol2)
  86 {
  87         if (vol1->vol_no < vol2->vol_no)
  88                 return(-1);
  89         if (vol1->vol_no > vol2->vol_no)
  90                 return(1);
  91         return(0);
  92 }
  93
  94 static int
  95 hammer_buf_rb_compare(hammer_buffer_t buf1, hammer_buffer_t buf2)
  96 {
  97         if (buf1->zone2_offset < buf2->zone2_offset)
  98                 return(-1);
  99         if (buf1->zone2_offset > buf2->zone2_offset)
 100                 return(1);
 101         return(0);
 102 }
 103
 104 static int
 105 hammer_nod_rb_compare(hammer_node_t node1, hammer_node_t node2)
 106 {
 107         if (node1->node_offset < node2->node_offset)
 108                 return(-1);
 109         if (node1->node_offset > node2->node_offset)
 110                 return(1);
 111         return(0);
 112 }
 113
 114 /*
 115  * Note: The lookup function for hammer_ino_rb_tree winds up being named
 116  * hammer_ino_rb_tree_RB_LOOKUP_INFO(root, info).  The other lookup
 117  * functions are normal, e.g. hammer_buf_rb_tree_RB_LOOKUP(root, zone2_offset).
 118  */
 119 RB_GENERATE(hammer_ino_rb_tree, hammer_inode, rb_node, hammer_ino_rb_compare);
 120 RB_GENERATE_XLOOKUP(hammer_ino_rb_tree, INFO, hammer_inode, rb_node,
 121                 hammer_inode_info_cmp, hammer_inode_info_t);
 122 RB_GENERATE2(hammer_vol_rb_tree, hammer_volume, rb_node,
 123              hammer_vol_rb_compare, int32_t, vol_no);
 124 RB_GENERATE2(hammer_buf_rb_tree, hammer_buffer, rb_node,
 125              hammer_buf_rb_compare, hammer_off_t, zone2_offset);
 126 RB_GENERATE2(hammer_nod_rb_tree, hammer_node, rb_node,
 127              hammer_nod_rb_compare, hammer_off_t, node_offset);
 128
 129 /************************************************************************
 130  *                              VOLUMES                                 *
 131  ************************************************************************
 132  *
 133  * Load a HAMMER volume by name.  Returns 0 on success or a positive error
 134  * code on failure.  Volumes must be loaded at mount time, get_volume() will
 135  * not load a new volume.
 136  *
 137  * Calls made to hammer_load_volume() or single-threaded
 138  */
 139 int
 140 hammer_install_volume(struct hammer_mount *hmp, const char *volname)
 141 {
 142         struct mount *mp;
 143         hammer_volume_t volume;
 144         struct hammer_volume_ondisk *ondisk;
 145         struct nlookupdata nd;
 146         struct buf *bp = NULL;
 147         int error;
 148         int ronly;
 149         int setmp = 0;
 150
 151         mp = hmp->mp;
 152         ronly = ((mp->mnt_flag & MNT_RDONLY) ? 1 : 0);
 153
 154         /*
 155          * Allocate a volume structure
 156          */
 157         ++hammer_count_volumes;
 158         volume = kmalloc(sizeof(*volume), M_HAMMER, M_WAITOK|M_ZERO);
 159         volume->vol_name = kstrdup(volname, M_HAMMER);
 160         volume->hmp = hmp;
 161         hammer_io_init(&volume->io, HAMMER_STRUCTURE_VOLUME);
 162         volume->io.offset = 0LL;
 163
 164         /*
 165          * Get the device vnode
 166          */
 167         error = nlookup_init(&nd, volume->vol_name, UIO_SYSSPACE, NLC_FOLLOW);
 168         if (error == 0)
 169                 error = nlookup(&nd);
 170         if (error == 0)
 171                 error = cache_vref(&nd.nl_nch, nd.nl_cred, &volume->devvp);
 172         nlookup_done(&nd);
 173         if (error == 0) {
 174                 if (vn_isdisk(volume->devvp, &error)) {
 175                         error = vfs_mountedon(volume->devvp);
 176                 }
 177         }
 178         if (error == 0 &&
 179             count_udev(volume->devvp->v_umajor, volume->devvp->v_uminor) > 0) {
 180                 error = EBUSY;
 181         }
 182         if (error == 0) {
 183                 vn_lock(volume->devvp, LK_EXCLUSIVE | LK_RETRY);
 184                 error = vinvalbuf(volume->devvp, V_SAVE, 0, 0);
 185                 if (error == 0) {
 186                         error = VOP_OPEN(volume->devvp,
 187                                          (ronly ? FREAD : FREAD|FWRITE),
 188                                          FSCRED, NULL);
 189                 }
 190                 vn_unlock(volume->devvp);
 191         }
 192         if (error) {
 193                 hammer_free_volume(volume);
 194                 return(error);
 195         }
 196         volume->devvp->v_rdev->si_mountpoint = mp;
 197         setmp = 1;
 198
 199         /*
 200          * Extract the volume number from the volume header and do various
 201          * sanity checks.
 202          */
 203         error = bread(volume->devvp, 0LL, HAMMER_BUFSIZE, &bp);
 204         if (error)
 205                 goto late_failure;
 206         ondisk = (void *)bp->b_data;
 207         if (ondisk->vol_signature != HAMMER_FSBUF_VOLUME) {
 208                 kprintf("hammer_mount: volume %s has an invalid header\n",
 209                         volume->vol_name);
 210                 error = EFTYPE;
 211                 goto late_failure;
 212         }
 213         volume->vol_no = ondisk->vol_no;
 214         volume->buffer_base = ondisk->vol_buf_beg;
 215         volume->vol_flags = ondisk->vol_flags;
 216         volume->nblocks = ondisk->vol_nblocks;
 217         volume->maxbuf_off = HAMMER_ENCODE_RAW_BUFFER(volume->vol_no,
 218                                     ondisk->vol_buf_end - ondisk->vol_buf_beg);
 219         RB_INIT(&volume->rb_bufs_root);
 220
 221         hmp->mp->mnt_stat.f_blocks += volume->nblocks;
 222
 223         if (RB_EMPTY(&hmp->rb_vols_root)) {
 224                 hmp->fsid = ondisk->vol_fsid;
 225         } else if (bcmp(&hmp->fsid, &ondisk->vol_fsid, sizeof(uuid_t))) {
 226                 kprintf("hammer_mount: volume %s's fsid does not match "
 227                         "other volumes\n", volume->vol_name);
 228                 error = EFTYPE;
 229                 goto late_failure;
 230         }
 231
 232         /*
 233          * Insert the volume structure into the red-black tree.
 234          */
 235         if (RB_INSERT(hammer_vol_rb_tree, &hmp->rb_vols_root, volume)) {
 236                 kprintf("hammer_mount: volume %s has a duplicate vol_no %d\n",
 237                         volume->vol_name, volume->vol_no);
 238                 error = EEXIST;
 239         }
 240
 241         /*
 242          * Set the root volume .  HAMMER special cases rootvol the structure.
 243          * We do not hold a ref because this would prevent related I/O
 244          * from being flushed.
 245          */
 246         if (error == 0 && ondisk->vol_rootvol == ondisk->vol_no) {
 247                 hmp->rootvol = volume;
 248                 if (bp) {
 249                         brelse(bp);
 250                         bp = NULL;
 251                 }
 252                 hmp->fsid_udev = dev2udev(vn_todev(volume->devvp));
 253         }
 254 late_failure:
 255         if (bp)
 256                 brelse(bp);
 257         if (error) {
 258                 /*vinvalbuf(volume->devvp, V_SAVE, 0, 0);*/
 259                 if (setmp)
 260                         volume->devvp->v_rdev->si_mountpoint = NULL;
 261                 VOP_CLOSE(volume->devvp, ronly ? FREAD : FREAD|FWRITE);
 262                 hammer_free_volume(volume);
 263         }
 264         return (error);
 265 }
 266
 267 /*
 268  * Unload and free a HAMMER volume.  Must return >= 0 to continue scan
 269  * so returns -1 on failure.
 270  */
 271 int
 272 hammer_unload_volume(hammer_volume_t volume, void *data __unused)
 273 {
 274         struct hammer_mount *hmp = volume->hmp;
 275         int ronly = ((hmp->mp->mnt_flag & MNT_RDONLY) ? 1 : 0);
 276
 277         /*
 278          * Sync clusters, sync volume
 279          */
 280
 281         hmp->mp->mnt_stat.f_blocks -= volume->nblocks;
 282
 283         /*
 284          * Clean up the root volume pointer, which is held unlocked in hmp.
 285          */
 286         if (hmp->rootvol == volume)
 287                 hmp->rootvol = NULL;
 288
 289         /*
 290          * Unload buffers.
 291          */
 292         RB_SCAN(hammer_buf_rb_tree, &volume->rb_bufs_root, NULL,
 293                         hammer_unload_buffer, NULL);
 294
 295         /*
 296          * Release our buffer and flush anything left in the buffer cache.
 297          */
 298         volume->io.flush = 1;
 299         volume->io.waitdep = 1;
 300         hammer_io_release(&volume->io);
 301
 302         /*
 303          * There should be no references on the volume, no clusters, and
 304          * no super-clusters.
 305          */
 306         KKASSERT(volume->io.lock.refs == 0);
 307         KKASSERT(RB_EMPTY(&volume->rb_bufs_root));
 308
 309         volume->ondisk = NULL;
 310         if (volume->devvp) {
 311                 if (volume->devvp->v_rdev &&
 312                     volume->devvp->v_rdev->si_mountpoint == hmp->mp
 313                 ) {
 314                         volume->devvp->v_rdev->si_mountpoint = NULL;
 315                 }
 316                 if (ronly) {
 317                         vinvalbuf(volume->devvp, 0, 0, 0);
 318                         VOP_CLOSE(volume->devvp, FREAD);
 319                 } else {
 320                         vinvalbuf(volume->devvp, V_SAVE, 0, 0);
 321                         VOP_CLOSE(volume->devvp, FREAD|FWRITE);
 322                 }
 323         }
 324
 325         /*
 326          * Destroy the structure
 327          */
 328         RB_REMOVE(hammer_vol_rb_tree, &hmp->rb_vols_root, volume);
 329         hammer_free_volume(volume);
 330         return(0);
 331 }
 332
 333 static
 334 void
 335 hammer_free_volume(hammer_volume_t volume)
 336 {
 337         if (volume->vol_name) {
 338                 kfree(volume->vol_name, M_HAMMER);
 339                 volume->vol_name = NULL;
 340         }
 341         if (volume->devvp) {
 342                 vrele(volume->devvp);
 343                 volume->devvp = NULL;
 344         }
 345         --hammer_count_volumes;
 346         kfree(volume, M_HAMMER);
 347 }
 348
 349 /*
 350  * Get a HAMMER volume.  The volume must already exist.
 351  */
 352 hammer_volume_t
 353 hammer_get_volume(struct hammer_mount *hmp, int32_t vol_no, int *errorp)
 354 {
 355         struct hammer_volume *volume;
 356
 357         /*
 358          * Locate the volume structure
 359          */
 360         volume = RB_LOOKUP(hammer_vol_rb_tree, &hmp->rb_vols_root, vol_no);
 361         if (volume == NULL) {
 362                 *errorp = ENOENT;
 363                 return(NULL);
 364         }
 365         hammer_ref(&volume->io.lock);
 366
 367         /*
 368          * Deal with on-disk info
 369          */
 370         if (volume->ondisk == NULL || volume->io.loading) {
 371                 *errorp = hammer_load_volume(volume);
 372                 if (*errorp) {
 373                         hammer_rel_volume(volume, 1);
 374                         volume = NULL;
 375                 }
 376         } else {
 377                 *errorp = 0;
 378         }
 379         return(volume);
 380 }
 381
 382 int
 383 hammer_ref_volume(hammer_volume_t volume)
 384 {
 385         int error;
 386
 387         hammer_ref(&volume->io.lock);
 388
 389         /*
 390          * Deal with on-disk info
 391          */
 392         if (volume->ondisk == NULL || volume->io.loading) {
 393                 error = hammer_load_volume(volume);
 394                 if (error)
 395                         hammer_rel_volume(volume, 1);
 396         } else {
 397                 error = 0;
 398         }
 399         return (error);
 400 }
 401
 402 hammer_volume_t
 403 hammer_get_root_volume(struct hammer_mount *hmp, int *errorp)
 404 {
 405         hammer_volume_t volume;
 406
 407         volume = hmp->rootvol;
 408         KKASSERT(volume != NULL);
 409         hammer_ref(&volume->io.lock);
 410
 411         /*
 412          * Deal with on-disk info
 413          */
 414         if (volume->ondisk == NULL || volume->io.loading) {
 415                 *errorp = hammer_load_volume(volume);
 416                 if (*errorp) {
 417                         hammer_rel_volume(volume, 1);
 418                         volume = NULL;
 419                 }
 420         } else {
 421                 *errorp = 0;
 422         }
 423         return (volume);
 424 }
 425
 426 /*
 427  * Load a volume's on-disk information.  The volume must be referenced and
 428  * not locked.  We temporarily acquire an exclusive lock to interlock
 429  * against releases or multiple get's.
 430  */
 431 static int
 432 hammer_load_volume(hammer_volume_t volume)
 433 {
 434         int error;
 435
 436         hammer_lock_ex(&volume->io.lock);
 437         KKASSERT(volume->io.loading == 0);
 438         ++volume->io.loading;
 439
 440         if (volume->ondisk == NULL) {
 441                 error = hammer_io_read(volume->devvp, &volume->io);
 442                 if (error == 0)
 443                         volume->ondisk = (void *)volume->io.bp->b_data;
 444         } else {
 445                 error = 0;
 446         }
 447         --volume->io.loading;
 448         hammer_unlock(&volume->io.lock);
 449         return(error);
 450 }
 451
 452 /*
 453  * Release a volume.  Call hammer_io_release on the last reference.  We have
 454  * to acquire an exclusive lock to interlock against volume->ondisk tests
 455  * in hammer_load_volume(), and hammer_io_release() also expects an exclusive
 456  * lock to be held.
 457  *
 458  * Volumes are not unloaded from memory during normal operation.
 459  */
 460 void
 461 hammer_rel_volume(hammer_volume_t volume, int flush)
 462 {
 463         if (flush)
 464                 volume->io.flush = 1;
 465         crit_enter();
 466         if (volume->io.lock.refs == 1) {
 467                 ++volume->io.loading;
 468                 hammer_lock_ex(&volume->io.lock);
 469                 if (volume->io.lock.refs == 1) {
 470                         volume->ondisk = NULL;
 471                         hammer_io_release(&volume->io);
 472                 }
 473                 --volume->io.loading;
 474                 hammer_unlock(&volume->io.lock);
 475         }
 476         hammer_unref(&volume->io.lock);
 477         crit_exit();
 478 }
 479
 480 /************************************************************************
 481  *                              BUFFERS                                 *
 482  ************************************************************************
 483  *
 484  * Manage buffers.  Currently all blockmap-backed zones are translated
 485  * to zone-2 buffer offsets.
 486  */
 487 hammer_buffer_t
 488 hammer_get_buffer(hammer_mount_t hmp, hammer_off_t buf_offset,
 489                   int isnew, int *errorp)
 490 {
 491         hammer_buffer_t buffer;
 492         hammer_volume_t volume;
 493         hammer_off_t    zoneX_offset;
 494         int vol_no;
 495         int zone;
 496
 497         zoneX_offset = buf_offset;
 498         zone = HAMMER_ZONE_DECODE(buf_offset);
 499         if (zone >= HAMMER_ZONE_BTREE_INDEX) {
 500                 buf_offset = hammer_blockmap_lookup(hmp, buf_offset, errorp);
 501                 KKASSERT(*errorp == 0);
 502         } else if (zone == HAMMER_ZONE_UNDO_INDEX) {
 503                 buf_offset = hammer_undo_lookup(hmp, buf_offset, errorp);
 504                 KKASSERT(*errorp == 0);
 505         }
 506         buf_offset &= ~HAMMER_BUFMASK64;
 507         KKASSERT((buf_offset & HAMMER_ZONE_RAW_BUFFER) ==
 508                  HAMMER_ZONE_RAW_BUFFER);
 509         vol_no = HAMMER_VOL_DECODE(buf_offset);
 510         volume = hammer_get_volume(hmp, vol_no, errorp);
 511         if (volume == NULL)
 512                 return(NULL);
 513
 514         /*
 515          * NOTE: buf_offset and maxbuf_off are both full offset
 516          * specifications.
 517          */
 518         KKASSERT(buf_offset < volume->maxbuf_off);
 519
 520         /*
 521          * Locate and lock the buffer structure, creating one if necessary.
 522          */
 523 again:
 524         buffer = RB_LOOKUP(hammer_buf_rb_tree, &volume->rb_bufs_root,
 525                            buf_offset);
 526         if (buffer == NULL) {
 527                 ++hammer_count_buffers;
 528                 buffer = kmalloc(sizeof(*buffer), M_HAMMER, M_WAITOK|M_ZERO);
 529                 buffer->zone2_offset = buf_offset;
 530                 buffer->volume = volume;
 531                 hammer_io_init(&buffer->io, HAMMER_STRUCTURE_BUFFER);
 532                 buffer->io.offset = volume->ondisk->vol_buf_beg +
 533                                     (buf_offset & HAMMER_OFF_SHORT_MASK);
 534                 TAILQ_INIT(&buffer->clist);
 535                 hammer_ref(&buffer->io.lock);
 536
 537                 /*
 538                  * Insert the buffer into the RB tree and handle late
 539                  * collisions.
 540                  */
 541                 if (RB_INSERT(hammer_buf_rb_tree, &volume->rb_bufs_root, buffer)) {
 542                         hammer_unref(&buffer->io.lock);
 543                         --hammer_count_buffers;
 544                         kfree(buffer, M_HAMMER);
 545                         goto again;
 546                 }
 547                 hammer_ref(&volume->io.lock);
 548         } else {
 549                 hammer_ref(&buffer->io.lock);
 550         }
 551
 552         /*
 553          * Cache the blockmap translation
 554          */
 555         if ((zoneX_offset & HAMMER_ZONE_RAW_BUFFER) != HAMMER_ZONE_RAW_BUFFER)
 556                 buffer->zoneX_offset = zoneX_offset;
 557
 558         /*
 559          * Deal with on-disk info
 560          */
 561         if (buffer->ondisk == NULL || buffer->io.loading) {
 562                 *errorp = hammer_load_buffer(buffer, isnew);
 563                 if (*errorp) {
 564                         hammer_rel_buffer(buffer, 1);
 565                         buffer = NULL;
 566                 }
 567         } else {
 568                 *errorp = 0;
 569         }
 570         hammer_rel_volume(volume, 0);
 571         return(buffer);
 572 }
 573
 574 static int
 575 hammer_load_buffer(hammer_buffer_t buffer, int isnew)
 576 {
 577         hammer_volume_t volume;
 578         int error;
 579
 580         /*
 581          * Load the buffer's on-disk info
 582          */
 583         volume = buffer->volume;
 584         ++buffer->io.loading;
 585         hammer_lock_ex(&buffer->io.lock);
 586
 587         if (buffer->ondisk == NULL) {
 588                 if (isnew) {
 589                         error = hammer_io_new(volume->devvp, &buffer->io);
 590                 } else {
 591                         error = hammer_io_read(volume->devvp, &buffer->io);
 592                 }
 593                 if (error == 0)
 594                         buffer->ondisk = (void *)buffer->io.bp->b_data;
 595         } else if (isnew) {
 596                 error = hammer_io_new(volume->devvp, &buffer->io);
 597         } else {
 598                 error = 0;
 599         }
 600         if (error == 0 && isnew) {
 601                 hammer_modify_buffer(NULL, buffer, NULL, 0);
 602                 /* additional initialization goes here */
 603         }
 604         --buffer->io.loading;
 605         hammer_unlock(&buffer->io.lock);
 606         return (error);
 607 }
 608
 609 /*
 610  * NOTE: Called from RB_SCAN, must return >= 0 for scan to continue.
 611  */
 612 int
 613 hammer_unload_buffer(hammer_buffer_t buffer, void *data __unused)
 614 {
 615         hammer_ref(&buffer->io.lock);
 616         hammer_flush_buffer_nodes(buffer);
 617         KKASSERT(buffer->io.lock.refs == 1);
 618         hammer_rel_buffer(buffer, 2);
 619         return(0);
 620 }
 621
 622 /*
 623  * Reference a buffer that is either already referenced or via a specially
 624  * handled pointer (aka cursor->buffer).
 625  */
 626 int
 627 hammer_ref_buffer(hammer_buffer_t buffer)
 628 {
 629         int error;
 630
 631         hammer_ref(&buffer->io.lock);
 632         if (buffer->ondisk == NULL || buffer->io.loading) {
 633                 error = hammer_load_buffer(buffer, 0);
 634                 if (error) {
 635                         hammer_rel_buffer(buffer, 1);
 636                         /*
 637                          * NOTE: buffer pointer can become stale after
 638                          * the above release.
 639                          */
 640                 }
 641         } else {
 642                 error = 0;
 643         }
 644         return(error);
 645 }
 646
 647 /*
 648  * Release a buffer.  We have to deal with several places where
 649  * another thread can ref the buffer.
 650  *
 651  * Only destroy the structure itself if the related buffer cache buffer
 652  * was disassociated from it.  This ties the management of the structure
 653  * to the buffer cache subsystem.  buffer->ondisk determines whether the
 654  * embedded io is referenced or not.
 655  */
 656 void
 657 hammer_rel_buffer(hammer_buffer_t buffer, int flush)
 658 {
 659         hammer_volume_t volume;
 660         int freeme = 0;
 661
 662         if (flush)
 663                 buffer->io.flush = 1;
 664         crit_enter();
 665         if (buffer->io.lock.refs == 1) {
 666                 ++buffer->io.loading;   /* force interlock check */
 667                 hammer_lock_ex(&buffer->io.lock);
 668                 if (buffer->io.lock.refs == 1) {
 669                         hammer_io_release(&buffer->io);
 670                         hammer_flush_buffer_nodes(buffer);
 671                         KKASSERT(TAILQ_EMPTY(&buffer->clist));
 672
 673                         if (buffer->io.bp == NULL &&
 674                             buffer->io.lock.refs == 1) {
 675                                 /*
 676                                  * Final cleanup
 677                                  */
 678                                 volume = buffer->volume;
 679                                 RB_REMOVE(hammer_buf_rb_tree,
 680                                           &volume->rb_bufs_root, buffer);
 681                                 buffer->volume = NULL; /* sanity */
 682                                 hammer_rel_volume(volume, 0);
 683                                 freeme = 1;
 684                         }
 685                 }
 686                 --buffer->io.loading;
 687                 hammer_unlock(&buffer->io.lock);
 688         }
 689         hammer_unref(&buffer->io.lock);
 690         crit_exit();
 691         if (freeme) {
 692                 --hammer_count_buffers;
 693                 kfree(buffer, M_HAMMER);
 694         }
 695 }
 696
 697 /*
 698  * Remove the zoneX translation cache for a buffer given its zone-2 offset.
 699  */
 700 void
 701 hammer_uncache_buffer(hammer_mount_t hmp, hammer_off_t buf_offset)
 702 {
 703         hammer_volume_t volume;
 704         hammer_buffer_t buffer;
 705         int vol_no;
 706         int error;
 707
 708         buf_offset &= ~HAMMER_BUFMASK64;
 709         KKASSERT((buf_offset & HAMMER_ZONE_RAW_BUFFER) ==
 710                  HAMMER_ZONE_RAW_BUFFER);
 711         vol_no = HAMMER_VOL_DECODE(buf_offset);
 712         volume = hammer_get_volume(hmp, vol_no, &error);
 713         KKASSERT(volume != 0);
 714         KKASSERT(buf_offset < volume->maxbuf_off);
 715
 716         buffer = RB_LOOKUP(hammer_buf_rb_tree, &volume->rb_bufs_root,
 717                            buf_offset);
 718         if (buffer)
 719                 buffer->zoneX_offset = 0;
 720         hammer_rel_volume(volume, 0);
 721 }
 722
 723 /*
 724  * Access the filesystem buffer containing the specified hammer offset.
 725  * buf_offset is a conglomeration of the volume number and vol_buf_beg
 726  * relative buffer offset.  It must also have bit 55 set to be valid.
 727  * (see hammer_off_t in hammer_disk.h).
 728  *
 729  * Any prior buffer in *bufferp will be released and replaced by the
 730  * requested buffer.
 731  */
 732 void *
 733 hammer_bread(hammer_mount_t hmp, hammer_off_t buf_offset, int *errorp,
 734              struct hammer_buffer **bufferp)
 735 {
 736         hammer_buffer_t buffer;
 737         int32_t xoff = (int32_t)buf_offset & HAMMER_BUFMASK;
 738
 739         buf_offset &= ~HAMMER_BUFMASK64;
 740         KKASSERT((buf_offset & HAMMER_OFF_ZONE_MASK) != 0);
 741
 742         buffer = *bufferp;
 743         if (buffer == NULL || (buffer->zone2_offset != buf_offset &&
 744                                buffer->zoneX_offset != buf_offset)) {
 745                 if (buffer)
 746                         hammer_rel_buffer(buffer, 0);
 747                 buffer = hammer_get_buffer(hmp, buf_offset, 0, errorp);
 748                 *bufferp = buffer;
 749         } else {
 750                 *errorp = 0;
 751         }
 752
 753         /*
 754          * Return a pointer to the buffer data.
 755          */
 756         if (buffer == NULL)
 757                 return(NULL);
 758         else
 759                 return((char *)buffer->ondisk + xoff);
 760 }
 761
 762 /*
 763  * Access the filesystem buffer containing the specified hammer offset.
 764  * No disk read operation occurs.  The result buffer may contain garbage.
 765  *
 766  * Any prior buffer in *bufferp will be released and replaced by the
 767  * requested buffer.
 768  */
 769 void *
 770 hammer_bnew(hammer_mount_t hmp, hammer_off_t buf_offset, int *errorp,
 771              struct hammer_buffer **bufferp)
 772 {
 773         hammer_buffer_t buffer;
 774         int32_t xoff = (int32_t)buf_offset & HAMMER_BUFMASK;
 775
 776         buf_offset &= ~HAMMER_BUFMASK64;
 777
 778         buffer = *bufferp;
 779         if (buffer == NULL || (buffer->zone2_offset != buf_offset &&
 780                                buffer->zoneX_offset != buf_offset)) {
 781                 if (buffer)
 782                         hammer_rel_buffer(buffer, 0);
 783                 buffer = hammer_get_buffer(hmp, buf_offset, 1, errorp);
 784                 *bufferp = buffer;
 785         } else {
 786                 *errorp = 0;
 787         }
 788
 789         /*
 790          * Return a pointer to the buffer data.
 791          */
 792         if (buffer == NULL)
 793                 return(NULL);
 794         else
 795                 return((char *)buffer->ondisk + xoff);
 796 }
 797
 798 /************************************************************************
 799  *                              NODES                                   *
 800  ************************************************************************
 801  *
 802  * Manage B-Tree nodes.  B-Tree nodes represent the primary indexing
 803  * method used by the HAMMER filesystem.
 804  *
 805  * Unlike other HAMMER structures, a hammer_node can be PASSIVELY
 806  * associated with its buffer, and will only referenced the buffer while
 807  * the node itself is referenced.
 808  *
 809  * A hammer_node can also be passively associated with other HAMMER
 810  * structures, such as inodes, while retaining 0 references.  These
 811  * associations can be cleared backwards using a pointer-to-pointer in
 812  * the hammer_node.
 813  *
 814  * This allows the HAMMER implementation to cache hammer_nodes long-term
 815  * and short-cut a great deal of the infrastructure's complexity.  In
 816  * most cases a cached node can be reacquired without having to dip into
 817  * either the buffer or cluster management code.
 818  *
 819  * The caller must pass a referenced cluster on call and will retain
 820  * ownership of the reference on return.  The node will acquire its own
 821  * additional references, if necessary.
 822  */
 823 hammer_node_t
 824 hammer_get_node(hammer_mount_t hmp, hammer_off_t node_offset, int *errorp)
 825 {
 826         hammer_node_t node;
 827
 828         KKASSERT((node_offset & HAMMER_OFF_ZONE_MASK) == HAMMER_ZONE_BTREE);
 829
 830         /*
 831          * Locate the structure, allocating one if necessary.
 832          */
 833 again:
 834         node = RB_LOOKUP(hammer_nod_rb_tree, &hmp->rb_nods_root, node_offset);
 835         if (node == NULL) {
 836                 ++hammer_count_nodes;
 837                 node = kmalloc(sizeof(*node), M_HAMMER, M_WAITOK|M_ZERO);
 838                 node->node_offset = node_offset;
 839                 node->hmp = hmp;
 840                 if (RB_INSERT(hammer_nod_rb_tree, &hmp->rb_nods_root, node)) {
 841                         --hammer_count_nodes;
 842                         kfree(node, M_HAMMER);
 843                         goto again;
 844                 }
 845         }
 846         hammer_ref(&node->lock);
 847         *errorp = hammer_load_node(node);
 848         if (*errorp) {
 849                 hammer_rel_node(node);
 850                 node = NULL;
 851         }
 852         return(node);
 853 }
 854
 855 /*
 856  * Reference an already-referenced node.
 857  */
 858 int
 859 hammer_ref_node(hammer_node_t node)
 860 {
 861         int error;
 862
 863         KKASSERT(node->lock.refs > 0);
 864         hammer_ref(&node->lock);
 865         if ((error = hammer_load_node(node)) != 0)
 866                 hammer_rel_node(node);
 867         return(error);
 868 }
 869
 870 /*
 871  * Load a node's on-disk data reference.
 872  */
 873 static int
 874 hammer_load_node(hammer_node_t node)
 875 {
 876         hammer_buffer_t buffer;
 877         int error;
 878
 879         if (node->ondisk)
 880                 return(0);
 881         error = 0;
 882         hammer_lock_ex(&node->lock);
 883         if (node->ondisk == NULL) {
 884                 /*
 885                  * This is a little confusing but the jist is that
 886                  * node->buffer determines whether the node is on
 887                  * the buffer's clist and node->ondisk determines
 888                  * whether the buffer is referenced.
 889                  */
 890                 if ((buffer = node->buffer) != NULL) {
 891                         error = hammer_ref_buffer(buffer);
 892                 } else {
 893                         buffer = hammer_get_buffer(node->hmp,
 894                                                    node->node_offset, 0,
 895                                                    &error);
 896                         if (buffer) {
 897                                 KKASSERT(error == 0);
 898                                 TAILQ_INSERT_TAIL(&buffer->clist,
 899                                                   node, entry);
 900                                 node->buffer = buffer;
 901                         }
 902                 }
 903                 if (error == 0) {
 904                         node->ondisk = (void *)((char *)buffer->ondisk +
 905                                (node->node_offset & HAMMER_BUFMASK));
 906                 }
 907         }
 908         hammer_unlock(&node->lock);
 909         return (error);
 910 }
 911
 912 /*
 913  * Safely reference a node, interlock against flushes via the IO subsystem.
 914  */
 915 hammer_node_t
 916 hammer_ref_node_safe(struct hammer_mount *hmp, struct hammer_node **cache,
 917                      int *errorp)
 918 {
 919         hammer_node_t node;
 920
 921         if ((node = *cache) != NULL)
 922                 hammer_ref(&node->lock);
 923         if (node) {
 924                 *errorp = hammer_load_node(node);
 925                 if (*errorp) {
 926                         hammer_rel_node(node);
 927                         node = NULL;
 928                 }
 929         } else {
 930                 *errorp = ENOENT;
 931         }
 932         return(node);
 933 }
 934
 935 /*
 936  * Release a hammer_node.  On the last release the node dereferences
 937  * its underlying buffer and may or may not be destroyed.
 938  */
 939 void
 940 hammer_rel_node(hammer_node_t node)
 941 {
 942         hammer_buffer_t buffer;
 943
 944         /*
 945          * If this isn't the last ref just decrement the ref count and
 946          * return.
 947          */
 948         if (node->lock.refs > 1) {
 949                 hammer_unref(&node->lock);
 950                 return;
 951         }
 952
 953         /*
 954          * If there is no ondisk info or no buffer the node failed to load,
 955          * remove the last reference and destroy the node.
 956          */
 957         if (node->ondisk == NULL) {
 958                 hammer_unref(&node->lock);
 959                 hammer_flush_node(node);
 960                 /* node is stale now */
 961                 return;
 962         }
 963
 964         /*
 965          * Do final cleanups and then either destroy the node and leave it
 966          * passively cached.  The buffer reference is removed regardless.
 967          */
 968         buffer = node->buffer;
 969         node->ondisk = NULL;
 970
 971         if ((node->flags & HAMMER_NODE_FLUSH) == 0) {
 972                 hammer_unref(&node->lock);
 973                 hammer_rel_buffer(buffer, 0);
 974                 return;
 975         }
 976
 977         /*
 978          * Destroy the node.
 979          */
 980         hammer_unref(&node->lock);
 981         hammer_flush_node(node);
 982         /* node is stale */
 983         hammer_rel_buffer(buffer, 0);
 984 }
 985
 986 /*
 987  *
 988  *
 989  */
 990 void
 991 hammer_delete_node(hammer_transaction_t trans, hammer_node_t node)
 992 {
 993         node->flags |= HAMMER_NODE_DELETED;
 994         hammer_blockmap_free(trans, node->node_offset, sizeof(*node->ondisk));
 995 }
 996
 997 /*
 998  * Passively cache a referenced hammer_node in *cache.  The caller may
 999  * release the node on return.
1000  */
1001 void
1002 hammer_cache_node(hammer_node_t node, struct hammer_node **cache)
1003 {
1004         hammer_node_t old;
1005
1006         /*
1007          * If the node is being deleted, don't cache it!
1008          */
1009         if (node->flags & HAMMER_NODE_DELETED)
1010                 return;
1011
1012         /*
1013          * Cache the node.  If we previously cached a different node we
1014          * have to give HAMMER a chance to destroy it.
1015          */
1016 again:
1017         if (node->cache1 != cache) {
1018                 if (node->cache2 != cache) {
1019                         if ((old = *cache) != NULL) {
1020                                 KKASSERT(node->lock.refs != 0);
1021                                 hammer_uncache_node(cache);
1022                                 goto again;
1023                         }
1024                         if (node->cache2)
1025                                 *node->cache2 = NULL;
1026                         node->cache2 = node->cache1;
1027                         node->cache1 = cache;
1028                         *cache = node;
1029                 } else {
1030                         struct hammer_node **tmp;
1031                         tmp = node->cache1;
1032                         node->cache1 = node->cache2;
1033                         node->cache2 = tmp;
1034                 }
1035         }
1036 }
1037
1038 void
1039 hammer_uncache_node(struct hammer_node **cache)
1040 {
1041         hammer_node_t node;
1042
1043         if ((node = *cache) != NULL) {
1044                 *cache = NULL;
1045                 if (node->cache1 == cache) {
1046                         node->cache1 = node->cache2;
1047                         node->cache2 = NULL;
1048                 } else if (node->cache2 == cache) {
1049                         node->cache2 = NULL;
1050                 } else {
1051                         panic("hammer_uncache_node: missing cache linkage");
1052                 }
1053                 if (node->cache1 == NULL && node->cache2 == NULL)
1054                         hammer_flush_node(node);
1055         }
1056 }
1057
1058 /*
1059  * Remove a node's cache references and destroy the node if it has no
1060  * other references or backing store.
1061  */
1062 void
1063 hammer_flush_node(hammer_node_t node)
1064 {
1065         hammer_buffer_t buffer;
1066
1067         if (node->cache1)
1068                 *node->cache1 = NULL;
1069         if (node->cache2)
1070                 *node->cache2 = NULL;
1071         if (node->lock.refs == 0 && node->ondisk == NULL) {
1072                 RB_REMOVE(hammer_nod_rb_tree, &node->hmp->rb_nods_root, node);
1073                 if ((buffer = node->buffer) != NULL) {
1074                         node->buffer = NULL;
1075                         TAILQ_REMOVE(&buffer->clist, node, entry);
1076                         /* buffer is unreferenced because ondisk is NULL */
1077                 }
1078                 --hammer_count_nodes;
1079                 kfree(node, M_HAMMER);
1080         }
1081 }
1082
1083 /*
1084  * Flush passively cached B-Tree nodes associated with this buffer.
1085  * This is only called when the buffer is about to be destroyed, so
1086  * none of the nodes should have any references.
1087  */
1088 void
1089 hammer_flush_buffer_nodes(hammer_buffer_t buffer)
1090 {
1091         hammer_node_t node;
1092
1093         while ((node = TAILQ_FIRST(&buffer->clist)) != NULL) {
1094                 KKASSERT(node->lock.refs == 0 && node->ondisk == NULL);
1095                 hammer_ref(&node->lock);
1096                 node->flags |= HAMMER_NODE_FLUSH;
1097                 hammer_rel_node(node);
1098         }
1099 }
1100
1101
1102 /************************************************************************
1103  *                              ALLOCATORS                              *
1104  ************************************************************************/
1105
1106 /*
1107  * Allocate a B-Tree node.
1108  */
1109 hammer_node_t
1110 hammer_alloc_btree(hammer_transaction_t trans, int *errorp)
1111 {
1112         hammer_buffer_t buffer = NULL;
1113         hammer_node_t node = NULL;
1114         hammer_off_t node_offset;
1115
1116         node_offset = hammer_blockmap_alloc(trans, HAMMER_ZONE_BTREE_INDEX,
1117                                             sizeof(struct hammer_node_ondisk),
1118                                             errorp);
1119         if (*errorp == 0) {
1120                 node = hammer_get_node(trans->hmp, node_offset, errorp);
1121                 hammer_modify_node_noundo(trans, node);
1122                 bzero(node->ondisk, sizeof(*node->ondisk));
1123         }
1124         if (buffer)
1125                 hammer_rel_buffer(buffer, 0);
1126         return(node);
1127 }
1128
1129 /*
1130  * The returned buffers are already appropriately marked as being modified.
1131  * If the caller marks them again unnecessary undo records may be generated.
1132  *
1133  * In-band data is indicated by data_bufferp == NULL.  Pass a data_len of 0
1134  * for zero-fill (caller modifies data_len afterwords).
1135  */
1136 void *
1137 hammer_alloc_record(hammer_transaction_t trans,
1138                     hammer_off_t *rec_offp, u_int16_t rec_type,
1139                     struct hammer_buffer **rec_bufferp,
1140                     int32_t data_len, void **datap,
1141                     struct hammer_buffer **data_bufferp, int *errorp)
1142 {
1143         hammer_record_ondisk_t rec;
1144         hammer_off_t rec_offset;
1145         hammer_off_t data_offset;
1146         int32_t reclen;
1147
1148         if (datap)
1149                 *datap = NULL;
1150
1151         /*
1152          * Allocate the record
1153          */
1154         rec_offset = hammer_blockmap_alloc(trans, HAMMER_ZONE_RECORD_INDEX,
1155                                            HAMMER_RECORD_SIZE, errorp);
1156         if (*errorp)
1157                 return(NULL);
1158
1159         /*
1160          * Allocate data
1161          */
1162         if (data_len) {
1163                 if (data_bufferp == NULL) {
1164                         switch(rec_type) {
1165                         case HAMMER_RECTYPE_DATA:
1166                                 reclen = offsetof(struct hammer_data_record,
1167                                                   data[0]);
1168                                 break;
1169                         case HAMMER_RECTYPE_DIRENTRY:
1170                                 reclen = offsetof(struct hammer_entry_record,
1171                                                   name[0]);
1172                                 break;
1173                         default:
1174                                 panic("hammer_alloc_record: illegal "
1175                                       "in-band data");
1176                                 /* NOT REACHED */
1177                                 reclen = 0;
1178                                 break;
1179                         }
1180                         KKASSERT(reclen + data_len <= HAMMER_RECORD_SIZE);
1181                         data_offset = rec_offset + reclen;
1182                 } else if (data_len < HAMMER_BUFSIZE) {
1183                         data_offset = hammer_blockmap_alloc(trans,
1184                                                 HAMMER_ZONE_SMALL_DATA_INDEX,
1185                                                 data_len, errorp);
1186                 } else {
1187                         data_offset = hammer_blockmap_alloc(trans,
1188                                                 HAMMER_ZONE_LARGE_DATA_INDEX,
1189                                                 data_len, errorp);
1190                 }
1191         } else {
1192                 data_offset = 0;
1193         }
1194         if (*errorp) {
1195                 hammer_blockmap_free(trans, rec_offset, HAMMER_RECORD_SIZE);
1196                 return(NULL);
1197         }
1198
1199         /*
1200          * Basic return values.
1201          */
1202         *rec_offp = rec_offset;
1203         rec = hammer_bread(trans->hmp, rec_offset, errorp, rec_bufferp);
1204         hammer_modify_buffer(trans, *rec_bufferp, NULL, 0);
1205         bzero(rec, sizeof(*rec));
1206         KKASSERT(*errorp == 0);
1207         rec->base.data_off = data_offset;
1208         rec->base.data_len = data_len;
1209
1210         if (data_bufferp) {
1211                 if (data_len) {
1212                         *datap = hammer_bread(trans->hmp, data_offset, errorp,
1213                                               data_bufferp);
1214                         KKASSERT(*errorp == 0);
1215                         hammer_modify_buffer(trans, *data_bufferp, NULL, 0);
1216                 } else {
1217                         *datap = NULL;
1218                 }
1219         } else if (data_len) {
1220                 KKASSERT(data_offset + data_len - rec_offset <=
1221                          HAMMER_RECORD_SIZE);
1222                 if (datap) {
1223                         *datap = (void *)((char *)rec +
1224                                           (int32_t)(data_offset - rec_offset));
1225                 }
1226         } else {
1227                 KKASSERT(datap == NULL);
1228         }
1229         KKASSERT(*errorp == 0);
1230         return(rec);
1231 }
1232
1233 void *
1234 hammer_alloc_data(hammer_transaction_t trans, int32_t data_len,
1235                   hammer_off_t *data_offsetp,
1236                   struct hammer_buffer **data_bufferp, int *errorp)
1237 {
1238         void *data;
1239
1240         /*
1241          * Allocate data
1242          */
1243         if (data_len) {
1244                 if (data_len < HAMMER_BUFSIZE) {
1245                         *data_offsetp = hammer_blockmap_alloc(trans,
1246                                                 HAMMER_ZONE_SMALL_DATA_INDEX,
1247                                                 data_len, errorp);
1248                 } else {
1249                         *data_offsetp = hammer_blockmap_alloc(trans,
1250                                                 HAMMER_ZONE_LARGE_DATA_INDEX,
1251                                                 data_len, errorp);
1252                 }
1253         } else {
1254                 *data_offsetp = 0;
1255         }
1256         if (*errorp == 0 && data_bufferp) {
1257                 if (data_len) {
1258                         data = hammer_bread(trans->hmp, *data_offsetp, errorp,
1259                                             data_bufferp);
1260                         KKASSERT(*errorp == 0);
1261                         hammer_modify_buffer(trans, *data_bufferp, NULL, 0);
1262                 } else {
1263                         data = NULL;
1264                 }
1265         } else {
1266                 data = NULL;
1267         }
1268         KKASSERT(*errorp == 0);
1269         return(data);
1270 }
1271
1272
1273 /*
1274  * Sync dirty buffers to the media
1275  */
1276
1277 static int hammer_sync_scan1(struct mount *mp, struct vnode *vp, void *data);
1278 static int hammer_sync_scan2(struct mount *mp, struct vnode *vp, void *data);
1279
1280 int
1281 hammer_sync_hmp(hammer_mount_t hmp, int waitfor)
1282 {
1283         struct hammer_sync_info info;
1284
1285         info.error = 0;
1286         info.waitfor = waitfor;
1287
1288         vmntvnodescan(hmp->mp, VMSC_GETVP|VMSC_NOWAIT,
1289                       hammer_sync_scan1, hammer_sync_scan2, &info);
1290
1291         RB_SCAN(hammer_vol_rb_tree, &hmp->rb_vols_root, NULL,
1292                 hammer_sync_volume, &info);
1293         return(info.error);
1294 }
1295
1296 static int
1297 hammer_sync_scan1(struct mount *mp, struct vnode *vp, void *data)
1298 {
1299         struct hammer_inode *ip;
1300
1301         ip = VTOI(vp);
1302         if (vp->v_type == VNON || ip == NULL ||
1303             ((ip->flags & HAMMER_INODE_MODMASK) == 0 &&
1304              RB_EMPTY(&vp->v_rbdirty_tree))) {
1305                 return(-1);
1306         }
1307         return(0);
1308 }
1309
1310 static int
1311 hammer_sync_scan2(struct mount *mp, struct vnode *vp, void *data)
1312 {
1313         struct hammer_sync_info *info = data;
1314         struct hammer_inode *ip;
1315         int error;
1316
1317         ip = VTOI(vp);
1318         if (vp->v_type == VNON || vp->v_type == VBAD ||
1319             ((ip->flags & HAMMER_INODE_MODMASK) == 0 &&
1320              RB_EMPTY(&vp->v_rbdirty_tree))) {
1321                 return(0);
1322         }
1323         error = VOP_FSYNC(vp, info->waitfor);
1324         if (error)
1325                 info->error = error;
1326         return(0);
1327 }
1328
1329 int
1330 hammer_sync_volume(hammer_volume_t volume, void *data)
1331 {
1332         struct hammer_sync_info *info = data;
1333
1334         hammer_ref(&volume->io.lock);
1335         RB_SCAN(hammer_buf_rb_tree, &volume->rb_bufs_root, NULL,
1336                 hammer_sync_buffer, info);
1337         hammer_rel_volume(volume, 1);
1338         return(0);
1339 }
1340
1341 int
1342 hammer_sync_buffer(hammer_buffer_t buffer, void *data __unused)
1343 {
1344         hammer_ref(&buffer->io.lock);
1345         hammer_rel_buffer(buffer, 1);
1346         return(0);
1347 }
1348