sys/vfs/hammer/hammer_ondisk.c

   1 /*
   2  * Copyright (c) 2007-2008 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 1.42 2008/05/12 21:17:18 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, int isnew);
  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         hammer_io_init(&volume->io, hmp, HAMMER_STRUCTURE_VOLUME);
 161         volume->io.offset = 0LL;
 162
 163         /*
 164          * Get the device vnode
 165          */
 166         error = nlookup_init(&nd, volume->vol_name, UIO_SYSSPACE, NLC_FOLLOW);
 167         if (error == 0)
 168                 error = nlookup(&nd);
 169         if (error == 0)
 170                 error = cache_vref(&nd.nl_nch, nd.nl_cred, &volume->devvp);
 171         nlookup_done(&nd);
 172         if (error == 0) {
 173                 if (vn_isdisk(volume->devvp, &error)) {
 174                         error = vfs_mountedon(volume->devvp);
 175                 }
 176         }
 177         if (error == 0 &&
 178             count_udev(volume->devvp->v_umajor, volume->devvp->v_uminor) > 0) {
 179                 error = EBUSY;
 180         }
 181         if (error == 0) {
 182                 vn_lock(volume->devvp, LK_EXCLUSIVE | LK_RETRY);
 183                 error = vinvalbuf(volume->devvp, V_SAVE, 0, 0);
 184                 if (error == 0) {
 185                         error = VOP_OPEN(volume->devvp,
 186                                          (ronly ? FREAD : FREAD|FWRITE),
 187                                          FSCRED, NULL);
 188                 }
 189                 vn_unlock(volume->devvp);
 190         }
 191         if (error) {
 192                 hammer_free_volume(volume);
 193                 return(error);
 194         }
 195         volume->devvp->v_rdev->si_mountpoint = mp;
 196         setmp = 1;
 197
 198         /*
 199          * Extract the volume number from the volume header and do various
 200          * sanity checks.
 201          */
 202         error = bread(volume->devvp, 0LL, HAMMER_BUFSIZE, &bp);
 203         if (error)
 204                 goto late_failure;
 205         ondisk = (void *)bp->b_data;
 206         if (ondisk->vol_signature != HAMMER_FSBUF_VOLUME) {
 207                 kprintf("hammer_mount: volume %s has an invalid header\n",
 208                         volume->vol_name);
 209                 error = EFTYPE;
 210                 goto late_failure;
 211         }
 212         volume->vol_no = ondisk->vol_no;
 213         volume->buffer_base = ondisk->vol_buf_beg;
 214         volume->vol_flags = ondisk->vol_flags;
 215         volume->nblocks = ondisk->vol_nblocks;
 216         volume->maxbuf_off = HAMMER_ENCODE_RAW_BUFFER(volume->vol_no,
 217                                     ondisk->vol_buf_end - ondisk->vol_buf_beg);
 218         RB_INIT(&volume->rb_bufs_root);
 219
 220         if (RB_EMPTY(&hmp->rb_vols_root)) {
 221                 hmp->fsid = ondisk->vol_fsid;
 222         } else if (bcmp(&hmp->fsid, &ondisk->vol_fsid, sizeof(uuid_t))) {
 223                 kprintf("hammer_mount: volume %s's fsid does not match "
 224                         "other volumes\n", volume->vol_name);
 225                 error = EFTYPE;
 226                 goto late_failure;
 227         }
 228
 229         /*
 230          * Insert the volume structure into the red-black tree.
 231          */
 232         if (RB_INSERT(hammer_vol_rb_tree, &hmp->rb_vols_root, volume)) {
 233                 kprintf("hammer_mount: volume %s has a duplicate vol_no %d\n",
 234                         volume->vol_name, volume->vol_no);
 235                 error = EEXIST;
 236         }
 237
 238         /*
 239          * Set the root volume .  HAMMER special cases rootvol the structure.
 240          * We do not hold a ref because this would prevent related I/O
 241          * from being flushed.
 242          */
 243         if (error == 0 && ondisk->vol_rootvol == ondisk->vol_no) {
 244                 hmp->rootvol = volume;
 245                 if (bp) {
 246                         brelse(bp);
 247                         bp = NULL;
 248                 }
 249                 hmp->fsid_udev = dev2udev(vn_todev(volume->devvp));
 250                 hmp->mp->mnt_stat.f_blocks += ondisk->vol0_stat_bigblocks *
 251                         (HAMMER_LARGEBLOCK_SIZE / HAMMER_BUFSIZE);
 252         }
 253 late_failure:
 254         if (bp)
 255                 brelse(bp);
 256         if (error) {
 257                 /*vinvalbuf(volume->devvp, V_SAVE, 0, 0);*/
 258                 if (setmp)
 259                         volume->devvp->v_rdev->si_mountpoint = NULL;
 260                 VOP_CLOSE(volume->devvp, ronly ? FREAD : FREAD|FWRITE);
 261                 hammer_free_volume(volume);
 262         }
 263         return (error);
 264 }
 265
 266 /*
 267  * Unload and free a HAMMER volume.  Must return >= 0 to continue scan
 268  * so returns -1 on failure.
 269  */
 270 int
 271 hammer_unload_volume(hammer_volume_t volume, void *data __unused)
 272 {
 273         struct hammer_mount *hmp = volume->io.hmp;
 274         int ronly = ((hmp->mp->mnt_flag & MNT_RDONLY) ? 1 : 0);
 275
 276         /*
 277          * Clean up the root volume pointer, which is held unlocked in hmp.
 278          */
 279         if (hmp->rootvol == volume)
 280                 hmp->rootvol = NULL;
 281
 282         /*
 283          * Unload buffers.
 284          */
 285         RB_SCAN(hammer_buf_rb_tree, &volume->rb_bufs_root, NULL,
 286                         hammer_unload_buffer, NULL);
 287
 288         /*
 289          * Release our buffer and flush anything left in the buffer cache.
 290          */
 291         volume->io.flush = 1;
 292         volume->io.waitdep = 1;
 293         hammer_io_release(&volume->io);
 294
 295         /*
 296          * There should be no references on the volume, no clusters, and
 297          * no super-clusters.
 298          */
 299         KKASSERT(volume->io.lock.refs == 0);
 300         KKASSERT(RB_EMPTY(&volume->rb_bufs_root));
 301
 302         volume->ondisk = NULL;
 303         if (volume->devvp) {
 304                 if (volume->devvp->v_rdev &&
 305                     volume->devvp->v_rdev->si_mountpoint == hmp->mp
 306                 ) {
 307                         volume->devvp->v_rdev->si_mountpoint = NULL;
 308                 }
 309                 if (ronly) {
 310                         vinvalbuf(volume->devvp, 0, 0, 0);
 311                         VOP_CLOSE(volume->devvp, FREAD);
 312                 } else {
 313                         vinvalbuf(volume->devvp, V_SAVE, 0, 0);
 314                         VOP_CLOSE(volume->devvp, FREAD|FWRITE);
 315                 }
 316         }
 317
 318         /*
 319          * Destroy the structure
 320          */
 321         RB_REMOVE(hammer_vol_rb_tree, &hmp->rb_vols_root, volume);
 322         hammer_free_volume(volume);
 323         return(0);
 324 }
 325
 326 static
 327 void
 328 hammer_free_volume(hammer_volume_t volume)
 329 {
 330         if (volume->vol_name) {
 331                 kfree(volume->vol_name, M_HAMMER);
 332                 volume->vol_name = NULL;
 333         }
 334         if (volume->devvp) {
 335                 vrele(volume->devvp);
 336                 volume->devvp = NULL;
 337         }
 338         --hammer_count_volumes;
 339         kfree(volume, M_HAMMER);
 340 }
 341
 342 /*
 343  * Get a HAMMER volume.  The volume must already exist.
 344  */
 345 hammer_volume_t
 346 hammer_get_volume(struct hammer_mount *hmp, int32_t vol_no, int *errorp)
 347 {
 348         struct hammer_volume *volume;
 349
 350         /*
 351          * Locate the volume structure
 352          */
 353         volume = RB_LOOKUP(hammer_vol_rb_tree, &hmp->rb_vols_root, vol_no);
 354         if (volume == NULL) {
 355                 *errorp = ENOENT;
 356                 return(NULL);
 357         }
 358         hammer_ref(&volume->io.lock);
 359
 360         /*
 361          * Deal with on-disk info
 362          */
 363         if (volume->ondisk == NULL || volume->io.loading) {
 364                 *errorp = hammer_load_volume(volume);
 365                 if (*errorp) {
 366                         hammer_rel_volume(volume, 1);
 367                         volume = NULL;
 368                 }
 369         } else {
 370                 *errorp = 0;
 371         }
 372         return(volume);
 373 }
 374
 375 int
 376 hammer_ref_volume(hammer_volume_t volume)
 377 {
 378         int error;
 379
 380         hammer_ref(&volume->io.lock);
 381
 382         /*
 383          * Deal with on-disk info
 384          */
 385         if (volume->ondisk == NULL || volume->io.loading) {
 386                 error = hammer_load_volume(volume);
 387                 if (error)
 388                         hammer_rel_volume(volume, 1);
 389         } else {
 390                 error = 0;
 391         }
 392         return (error);
 393 }
 394
 395 hammer_volume_t
 396 hammer_get_root_volume(struct hammer_mount *hmp, int *errorp)
 397 {
 398         hammer_volume_t volume;
 399
 400         volume = hmp->rootvol;
 401         KKASSERT(volume != NULL);
 402         hammer_ref(&volume->io.lock);
 403
 404         /*
 405          * Deal with on-disk info
 406          */
 407         if (volume->ondisk == NULL || volume->io.loading) {
 408                 *errorp = hammer_load_volume(volume);
 409                 if (*errorp) {
 410                         hammer_rel_volume(volume, 1);
 411                         volume = NULL;
 412                 }
 413         } else {
 414                 *errorp = 0;
 415         }
 416         return (volume);
 417 }
 418
 419 /*
 420  * Load a volume's on-disk information.  The volume must be referenced and
 421  * not locked.  We temporarily acquire an exclusive lock to interlock
 422  * against releases or multiple get's.
 423  */
 424 static int
 425 hammer_load_volume(hammer_volume_t volume)
 426 {
 427         int error;
 428
 429         ++volume->io.loading;
 430         hammer_lock_ex(&volume->io.lock);
 431
 432         if (volume->ondisk == NULL) {
 433                 error = hammer_io_read(volume->devvp, &volume->io);
 434                 if (error == 0)
 435                         volume->ondisk = (void *)volume->io.bp->b_data;
 436         } else {
 437                 error = 0;
 438         }
 439         --volume->io.loading;
 440         hammer_unlock(&volume->io.lock);
 441         return(error);
 442 }
 443
 444 /*
 445  * Release a volume.  Call hammer_io_release on the last reference.  We have
 446  * to acquire an exclusive lock to interlock against volume->ondisk tests
 447  * in hammer_load_volume(), and hammer_io_release() also expects an exclusive
 448  * lock to be held.
 449  *
 450  * Volumes are not unloaded from memory during normal operation.
 451  */
 452 void
 453 hammer_rel_volume(hammer_volume_t volume, int flush)
 454 {
 455         if (flush)
 456                 volume->io.flush = 1;
 457         crit_enter();
 458         if (volume->io.lock.refs == 1) {
 459                 ++volume->io.loading;
 460                 hammer_lock_ex(&volume->io.lock);
 461                 if (volume->io.lock.refs == 1) {
 462                         volume->ondisk = NULL;
 463                         hammer_io_release(&volume->io);
 464                 }
 465                 --volume->io.loading;
 466                 hammer_unlock(&volume->io.lock);
 467         }
 468         hammer_unref(&volume->io.lock);
 469         crit_exit();
 470 }
 471
 472 /************************************************************************
 473  *                              BUFFERS                                 *
 474  ************************************************************************
 475  *
 476  * Manage buffers.  Currently all blockmap-backed zones are translated
 477  * to zone-2 buffer offsets.
 478  */
 479 hammer_buffer_t
 480 hammer_get_buffer(hammer_mount_t hmp, hammer_off_t buf_offset,
 481                   int isnew, int *errorp)
 482 {
 483         hammer_buffer_t buffer;
 484         hammer_volume_t volume;
 485         hammer_off_t    zoneX_offset;
 486         hammer_io_type_t iotype;
 487         int vol_no;
 488         int zone;
 489
 490         zoneX_offset = buf_offset;
 491         zone = HAMMER_ZONE_DECODE(buf_offset);
 492
 493         /*
 494          * What is the buffer class?
 495          */
 496         switch(zone) {
 497         case HAMMER_ZONE_LARGE_DATA_INDEX:
 498         case HAMMER_ZONE_SMALL_DATA_INDEX:
 499                 iotype = HAMMER_STRUCTURE_DATA_BUFFER;
 500                 break;
 501         case HAMMER_ZONE_UNDO_INDEX:
 502                 iotype = HAMMER_STRUCTURE_UNDO_BUFFER;
 503                 break;
 504         default:
 505                 iotype = HAMMER_STRUCTURE_META_BUFFER;
 506                 break;
 507         }
 508
 509         /*
 510          * Handle blockmap offset translations
 511          */
 512         if (zone >= HAMMER_ZONE_BTREE_INDEX) {
 513                 buf_offset = hammer_blockmap_lookup(hmp, buf_offset, errorp);
 514                 KKASSERT(*errorp == 0);
 515         } else if (zone == HAMMER_ZONE_UNDO_INDEX) {
 516                 buf_offset = hammer_undo_lookup(hmp, buf_offset, errorp);
 517                 KKASSERT(*errorp == 0);
 518         }
 519
 520         /*
 521          * Locate the buffer given its zone-2 offset.
 522          */
 523         buf_offset &= ~HAMMER_BUFMASK64;
 524         KKASSERT((buf_offset & HAMMER_ZONE_RAW_BUFFER) ==
 525                  HAMMER_ZONE_RAW_BUFFER);
 526         vol_no = HAMMER_VOL_DECODE(buf_offset);
 527         volume = hammer_get_volume(hmp, vol_no, errorp);
 528         if (volume == NULL)
 529                 return(NULL);
 530
 531         /*
 532          * NOTE: buf_offset and maxbuf_off are both full offset
 533          * specifications.
 534          */
 535         KKASSERT(buf_offset < volume->maxbuf_off);
 536
 537         /*
 538          * Locate and lock the buffer structure, creating one if necessary.
 539          */
 540 again:
 541         buffer = RB_LOOKUP(hammer_buf_rb_tree, &volume->rb_bufs_root,
 542                            buf_offset);
 543         if (buffer == NULL) {
 544                 ++hammer_count_buffers;
 545                 buffer = kmalloc(sizeof(*buffer), M_HAMMER, M_WAITOK|M_ZERO);
 546                 buffer->zone2_offset = buf_offset;
 547                 buffer->volume = volume;
 548
 549                 hammer_io_init(&buffer->io, hmp, iotype);
 550                 buffer->io.offset = volume->ondisk->vol_buf_beg +
 551                                     (buf_offset & HAMMER_OFF_SHORT_MASK);
 552                 TAILQ_INIT(&buffer->clist);
 553                 hammer_ref(&buffer->io.lock);
 554
 555                 /*
 556                  * Insert the buffer into the RB tree and handle late
 557                  * collisions.
 558                  */
 559                 if (RB_INSERT(hammer_buf_rb_tree, &volume->rb_bufs_root, buffer)) {
 560                         hammer_unref(&buffer->io.lock);
 561                         --hammer_count_buffers;
 562                         kfree(buffer, M_HAMMER);
 563                         goto again;
 564                 }
 565                 hammer_ref(&volume->io.lock);
 566         } else {
 567                 hammer_ref(&buffer->io.lock);
 568
 569                 /*
 570                  * The buffer is no longer loose if it has a ref.
 571                  */
 572                 if (buffer->io.mod_list == &hmp->lose_list) {
 573                         TAILQ_REMOVE(buffer->io.mod_list, &buffer->io,
 574                                      mod_entry);
 575                         buffer->io.mod_list = NULL;
 576                 }
 577                 if (buffer->io.lock.refs == 1)
 578                         hammer_io_reinit(&buffer->io, iotype);
 579                 else
 580                         KKASSERT(buffer->io.type == iotype);
 581         }
 582
 583         /*
 584          * Cache the blockmap translation
 585          */
 586         if ((zoneX_offset & HAMMER_ZONE_RAW_BUFFER) != HAMMER_ZONE_RAW_BUFFER)
 587                 buffer->zoneX_offset = zoneX_offset;
 588
 589         /*
 590          * Deal with on-disk info
 591          */
 592         if (buffer->ondisk == NULL || buffer->io.loading) {
 593                 *errorp = hammer_load_buffer(buffer, isnew);
 594                 if (*errorp) {
 595                         hammer_rel_buffer(buffer, 1);
 596                         buffer = NULL;
 597                 }
 598         } else {
 599                 *errorp = 0;
 600         }
 601         hammer_rel_volume(volume, 0);
 602         return(buffer);
 603 }
 604
 605 static int
 606 hammer_load_buffer(hammer_buffer_t buffer, int isnew)
 607 {
 608         hammer_volume_t volume;
 609         int error;
 610
 611         /*
 612          * Load the buffer's on-disk info
 613          */
 614         volume = buffer->volume;
 615         ++buffer->io.loading;
 616         hammer_lock_ex(&buffer->io.lock);
 617
 618         if (buffer->ondisk == NULL) {
 619                 if (isnew) {
 620                         error = hammer_io_new(volume->devvp, &buffer->io);
 621                 } else {
 622                         error = hammer_io_read(volume->devvp, &buffer->io);
 623                 }
 624                 if (error == 0)
 625                         buffer->ondisk = (void *)buffer->io.bp->b_data;
 626         } else if (isnew) {
 627                 error = hammer_io_new(volume->devvp, &buffer->io);
 628         } else {
 629                 error = 0;
 630         }
 631         --buffer->io.loading;
 632         hammer_unlock(&buffer->io.lock);
 633         return (error);
 634 }
 635
 636 /*
 637  * NOTE: Called from RB_SCAN, must return >= 0 for scan to continue.
 638  */
 639 int
 640 hammer_unload_buffer(hammer_buffer_t buffer, void *data __unused)
 641 {
 642         hammer_ref(&buffer->io.lock);
 643         hammer_flush_buffer_nodes(buffer);
 644         KKASSERT(buffer->io.lock.refs == 1);
 645         hammer_rel_buffer(buffer, 2);
 646         return(0);
 647 }
 648
 649 /*
 650  * Reference a buffer that is either already referenced or via a specially
 651  * handled pointer (aka cursor->buffer).
 652  */
 653 int
 654 hammer_ref_buffer(hammer_buffer_t buffer)
 655 {
 656         int error;
 657
 658         hammer_ref(&buffer->io.lock);
 659
 660         /*
 661          * No longer loose
 662          */
 663         if (buffer->io.mod_list == &buffer->io.hmp->lose_list) {
 664                 TAILQ_REMOVE(buffer->io.mod_list, &buffer->io, mod_entry);
 665                 buffer->io.mod_list = NULL;
 666         }
 667
 668         if (buffer->ondisk == NULL || buffer->io.loading) {
 669                 error = hammer_load_buffer(buffer, 0);
 670                 if (error) {
 671                         hammer_rel_buffer(buffer, 1);
 672                         /*
 673                          * NOTE: buffer pointer can become stale after
 674                          * the above release.
 675                          */
 676                 }
 677         } else {
 678                 error = 0;
 679         }
 680         return(error);
 681 }
 682
 683 /*
 684  * Release a buffer.  We have to deal with several places where
 685  * another thread can ref the buffer.
 686  *
 687  * Only destroy the structure itself if the related buffer cache buffer
 688  * was disassociated from it.  This ties the management of the structure
 689  * to the buffer cache subsystem.  buffer->ondisk determines whether the
 690  * embedded io is referenced or not.
 691  */
 692 void
 693 hammer_rel_buffer(hammer_buffer_t buffer, int flush)
 694 {
 695         hammer_volume_t volume;
 696         int freeme = 0;
 697
 698         if (flush)
 699                 buffer->io.flush = 1;
 700         crit_enter();
 701         if (buffer->io.lock.refs == 1) {
 702                 ++buffer->io.loading;   /* force interlock check */
 703                 hammer_lock_ex(&buffer->io.lock);
 704                 if (buffer->io.lock.refs == 1) {
 705                         hammer_io_release(&buffer->io);
 706                         hammer_flush_buffer_nodes(buffer);
 707                         KKASSERT(TAILQ_EMPTY(&buffer->clist));
 708
 709                         if (buffer->io.bp == NULL &&
 710                             buffer->io.lock.refs == 1) {
 711                                 /*
 712                                  * Final cleanup
 713                                  */
 714                                 volume = buffer->volume;
 715                                 RB_REMOVE(hammer_buf_rb_tree,
 716                                           &volume->rb_bufs_root, buffer);
 717                                 buffer->volume = NULL; /* sanity */
 718                                 hammer_rel_volume(volume, 0);
 719                                 freeme = 1;
 720                         }
 721                 }
 722                 --buffer->io.loading;
 723                 hammer_unlock(&buffer->io.lock);
 724         }
 725         hammer_unref(&buffer->io.lock);
 726         crit_exit();
 727         if (freeme) {
 728                 KKASSERT(buffer->io.mod_list == NULL);
 729                 --hammer_count_buffers;
 730                 kfree(buffer, M_HAMMER);
 731         }
 732 }
 733
 734 /*
 735  * Remove the zoneX translation cache for a buffer given its zone-2 offset.
 736  */
 737 void
 738 hammer_uncache_buffer(hammer_mount_t hmp, hammer_off_t buf_offset)
 739 {
 740         hammer_volume_t volume;
 741         hammer_buffer_t buffer;
 742         int vol_no;
 743         int error;
 744
 745         buf_offset &= ~HAMMER_BUFMASK64;
 746         KKASSERT((buf_offset & HAMMER_ZONE_RAW_BUFFER) ==
 747                  HAMMER_ZONE_RAW_BUFFER);
 748         vol_no = HAMMER_VOL_DECODE(buf_offset);
 749         volume = hammer_get_volume(hmp, vol_no, &error);
 750         KKASSERT(volume != 0);
 751         KKASSERT(buf_offset < volume->maxbuf_off);
 752
 753         buffer = RB_LOOKUP(hammer_buf_rb_tree, &volume->rb_bufs_root,
 754                            buf_offset);
 755         if (buffer)
 756                 buffer->zoneX_offset = 0;
 757         hammer_rel_volume(volume, 0);
 758 }
 759
 760 /*
 761  * Access the filesystem buffer containing the specified hammer offset.
 762  * buf_offset is a conglomeration of the volume number and vol_buf_beg
 763  * relative buffer offset.  It must also have bit 55 set to be valid.
 764  * (see hammer_off_t in hammer_disk.h).
 765  *
 766  * Any prior buffer in *bufferp will be released and replaced by the
 767  * requested buffer.
 768  */
 769 void *
 770 hammer_bread(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         KKASSERT((buf_offset & HAMMER_OFF_ZONE_MASK) != 0);
 778
 779         buffer = *bufferp;
 780         if (buffer == NULL || (buffer->zone2_offset != buf_offset &&
 781                                buffer->zoneX_offset != buf_offset)) {
 782                 if (buffer)
 783                         hammer_rel_buffer(buffer, 0);
 784                 buffer = hammer_get_buffer(hmp, buf_offset, 0, errorp);
 785                 *bufferp = buffer;
 786         } else {
 787                 *errorp = 0;
 788         }
 789
 790         /*
 791          * Return a pointer to the buffer data.
 792          */
 793         if (buffer == NULL)
 794                 return(NULL);
 795         else
 796                 return((char *)buffer->ondisk + xoff);
 797 }
 798
 799 /*
 800  * Access the filesystem buffer containing the specified hammer offset.
 801  * No disk read operation occurs.  The result buffer may contain garbage.
 802  *
 803  * Any prior buffer in *bufferp will be released and replaced by the
 804  * requested buffer.
 805  *
 806  * This function marks the buffer dirty but does not increment its
 807  * modify_refs count.
 808  */
 809 void *
 810 hammer_bnew(hammer_mount_t hmp, hammer_off_t buf_offset, int *errorp,
 811              struct hammer_buffer **bufferp)
 812 {
 813         hammer_buffer_t buffer;
 814         int32_t xoff = (int32_t)buf_offset & HAMMER_BUFMASK;
 815
 816         buf_offset &= ~HAMMER_BUFMASK64;
 817
 818         buffer = *bufferp;
 819         if (buffer == NULL || (buffer->zone2_offset != buf_offset &&
 820                                buffer->zoneX_offset != buf_offset)) {
 821                 if (buffer)
 822                         hammer_rel_buffer(buffer, 0);
 823                 buffer = hammer_get_buffer(hmp, buf_offset, 1, errorp);
 824                 *bufferp = buffer;
 825         } else {
 826                 *errorp = 0;
 827         }
 828
 829         /*
 830          * Return a pointer to the buffer data.
 831          */
 832         if (buffer == NULL)
 833                 return(NULL);
 834         else
 835                 return((char *)buffer->ondisk + xoff);
 836 }
 837
 838 /************************************************************************
 839  *                              NODES                                   *
 840  ************************************************************************
 841  *
 842  * Manage B-Tree nodes.  B-Tree nodes represent the primary indexing
 843  * method used by the HAMMER filesystem.
 844  *
 845  * Unlike other HAMMER structures, a hammer_node can be PASSIVELY
 846  * associated with its buffer, and will only referenced the buffer while
 847  * the node itself is referenced.
 848  *
 849  * A hammer_node can also be passively associated with other HAMMER
 850  * structures, such as inodes, while retaining 0 references.  These
 851  * associations can be cleared backwards using a pointer-to-pointer in
 852  * the hammer_node.
 853  *
 854  * This allows the HAMMER implementation to cache hammer_nodes long-term
 855  * and short-cut a great deal of the infrastructure's complexity.  In
 856  * most cases a cached node can be reacquired without having to dip into
 857  * either the buffer or cluster management code.
 858  *
 859  * The caller must pass a referenced cluster on call and will retain
 860  * ownership of the reference on return.  The node will acquire its own
 861  * additional references, if necessary.
 862  */
 863 hammer_node_t
 864 hammer_get_node(hammer_mount_t hmp, hammer_off_t node_offset,
 865                 int isnew, int *errorp)
 866 {
 867         hammer_node_t node;
 868
 869         KKASSERT((node_offset & HAMMER_OFF_ZONE_MASK) == HAMMER_ZONE_BTREE);
 870
 871         /*
 872          * Locate the structure, allocating one if necessary.
 873          */
 874 again:
 875         node = RB_LOOKUP(hammer_nod_rb_tree, &hmp->rb_nods_root, node_offset);
 876         if (node == NULL) {
 877                 ++hammer_count_nodes;
 878                 node = kmalloc(sizeof(*node), M_HAMMER, M_WAITOK|M_ZERO);
 879                 node->node_offset = node_offset;
 880                 node->hmp = hmp;
 881                 if (RB_INSERT(hammer_nod_rb_tree, &hmp->rb_nods_root, node)) {
 882                         --hammer_count_nodes;
 883                         kfree(node, M_HAMMER);
 884                         goto again;
 885                 }
 886         }
 887         hammer_ref(&node->lock);
 888         if (node->ondisk)
 889                 *errorp = 0;
 890         else
 891                 *errorp = hammer_load_node(node, isnew);
 892         if (*errorp) {
 893                 hammer_rel_node(node);
 894                 node = NULL;
 895         }
 896         return(node);
 897 }
 898
 899 /*
 900  * Reference an already-referenced node.
 901  */
 902 void
 903 hammer_ref_node(hammer_node_t node)
 904 {
 905         KKASSERT(node->lock.refs > 0 && node->ondisk != NULL);
 906         hammer_ref(&node->lock);
 907 }
 908
 909 /*
 910  * Load a node's on-disk data reference.
 911  */
 912 static int
 913 hammer_load_node(hammer_node_t node, int isnew)
 914 {
 915         hammer_buffer_t buffer;
 916         int error;
 917
 918         error = 0;
 919         ++node->loading;
 920         hammer_lock_ex(&node->lock);
 921         if (node->ondisk == NULL) {
 922                 /*
 923                  * This is a little confusing but the jist is that
 924                  * node->buffer determines whether the node is on
 925                  * the buffer's clist and node->ondisk determines
 926                  * whether the buffer is referenced.
 927                  *
 928                  * We could be racing a buffer release, in which case
 929                  * node->buffer may become NULL while we are blocked
 930                  * referencing the buffer.
 931                  */
 932                 if ((buffer = node->buffer) != NULL) {
 933                         error = hammer_ref_buffer(buffer);
 934                         if (error == 0 && node->buffer == NULL) {
 935                                 TAILQ_INSERT_TAIL(&buffer->clist,
 936                                                   node, entry);
 937                                 node->buffer = buffer;
 938                         }
 939                 } else {
 940                         buffer = hammer_get_buffer(node->hmp,
 941                                                    node->node_offset, 0,
 942                                                    &error);
 943                         if (buffer) {
 944                                 KKASSERT(error == 0);
 945                                 TAILQ_INSERT_TAIL(&buffer->clist,
 946                                                   node, entry);
 947                                 node->buffer = buffer;
 948                         }
 949                 }
 950                 if (error == 0) {
 951                         node->ondisk = (void *)((char *)buffer->ondisk +
 952                                (node->node_offset & HAMMER_BUFMASK));
 953                         if (isnew == 0 &&
 954                             hammer_crc_test_btree(node->ondisk) == 0) {
 955                                 Debugger("CRC FAILED: B-TREE NODE");
 956                         }
 957                 }
 958         }
 959         --node->loading;
 960         hammer_unlock(&node->lock);
 961         return (error);
 962 }
 963
 964 /*
 965  * Safely reference a node, interlock against flushes via the IO subsystem.
 966  */
 967 hammer_node_t
 968 hammer_ref_node_safe(struct hammer_mount *hmp, struct hammer_node **cache,
 969                      int *errorp)
 970 {
 971         hammer_node_t node;
 972
 973         node = *cache;
 974         if (node != NULL) {
 975                 hammer_ref(&node->lock);
 976                 if (node->ondisk)
 977                         *errorp = 0;
 978                 else
 979                         *errorp = hammer_load_node(node, 0);
 980                 if (*errorp) {
 981                         hammer_rel_node(node);
 982                         node = NULL;
 983                 }
 984         } else {
 985                 *errorp = ENOENT;
 986         }
 987         return(node);
 988 }
 989
 990 /*
 991  * Release a hammer_node.  On the last release the node dereferences
 992  * its underlying buffer and may or may not be destroyed.
 993  */
 994 void
 995 hammer_rel_node(hammer_node_t node)
 996 {
 997         hammer_buffer_t buffer;
 998
 999         /*
1000          * If this isn't the last ref just decrement the ref count and
1001          * return.
1002          */
1003         if (node->lock.refs > 1) {
1004                 hammer_unref(&node->lock);
1005                 return;
1006         }
1007
1008         /*
1009          * If there is no ondisk info or no buffer the node failed to load,
1010          * remove the last reference and destroy the node.
1011          */
1012         if (node->ondisk == NULL) {
1013                 hammer_unref(&node->lock);
1014                 hammer_flush_node(node);
1015                 /* node is stale now */
1016                 return;
1017         }
1018
1019         /*
1020          * Do final cleanups and then either destroy the node and leave it
1021          * passively cached.  The buffer reference is removed regardless.
1022          */
1023         buffer = node->buffer;
1024         node->ondisk = NULL;
1025
1026         if ((node->flags & HAMMER_NODE_FLUSH) == 0) {
1027                 hammer_unref(&node->lock);
1028                 hammer_rel_buffer(buffer, 0);
1029                 return;
1030         }
1031
1032         /*
1033          * Destroy the node.
1034          */
1035         hammer_unref(&node->lock);
1036         hammer_flush_node(node);
1037         /* node is stale */
1038         hammer_rel_buffer(buffer, 0);
1039 }
1040
1041 /*
1042  * Free space on-media associated with a B-Tree node.
1043  */
1044 void
1045 hammer_delete_node(hammer_transaction_t trans, hammer_node_t node)
1046 {
1047         node->flags |= HAMMER_NODE_DELETED;
1048         hammer_blockmap_free(trans, node->node_offset, sizeof(*node->ondisk));
1049 }
1050
1051 /*
1052  * Passively cache a referenced hammer_node in *cache.  The caller may
1053  * release the node on return.
1054  */
1055 void
1056 hammer_cache_node(hammer_node_t node, struct hammer_node **cache)
1057 {
1058         hammer_node_t old;
1059
1060         /*
1061          * If the node is being deleted, don't cache it!
1062          */
1063         if (node->flags & HAMMER_NODE_DELETED)
1064                 return;
1065
1066         /*
1067          * Cache the node.  If we previously cached a different node we
1068          * have to give HAMMER a chance to destroy it.
1069          */
1070 again:
1071         if (node->cache1 != cache) {
1072                 if (node->cache2 != cache) {
1073                         if ((old = *cache) != NULL) {
1074                                 KKASSERT(node->lock.refs != 0);
1075                                 hammer_uncache_node(cache);
1076                                 goto again;
1077                         }
1078                         if (node->cache2)
1079                                 *node->cache2 = NULL;
1080                         node->cache2 = node->cache1;
1081                         node->cache1 = cache;
1082                         *cache = node;
1083                 } else {
1084                         struct hammer_node **tmp;
1085                         tmp = node->cache1;
1086                         node->cache1 = node->cache2;
1087                         node->cache2 = tmp;
1088                 }
1089         }
1090 }
1091
1092 void
1093 hammer_uncache_node(struct hammer_node **cache)
1094 {
1095         hammer_node_t node;
1096
1097         if ((node = *cache) != NULL) {
1098                 *cache = NULL;
1099                 if (node->cache1 == cache) {
1100                         node->cache1 = node->cache2;
1101                         node->cache2 = NULL;
1102                 } else if (node->cache2 == cache) {
1103                         node->cache2 = NULL;
1104                 } else {
1105                         panic("hammer_uncache_node: missing cache linkage");
1106                 }
1107                 if (node->cache1 == NULL && node->cache2 == NULL)
1108                         hammer_flush_node(node);
1109         }
1110 }
1111
1112 /*
1113  * Remove a node's cache references and destroy the node if it has no
1114  * other references or backing store.
1115  */
1116 void
1117 hammer_flush_node(hammer_node_t node)
1118 {
1119         hammer_buffer_t buffer;
1120
1121         if (node->cache1)
1122                 *node->cache1 = NULL;
1123         if (node->cache2)
1124                 *node->cache2 = NULL;
1125         if (node->lock.refs == 0 && node->ondisk == NULL) {
1126                 RB_REMOVE(hammer_nod_rb_tree, &node->hmp->rb_nods_root, node);
1127                 if ((buffer = node->buffer) != NULL) {
1128                         node->buffer = NULL;
1129                         TAILQ_REMOVE(&buffer->clist, node, entry);
1130                         /* buffer is unreferenced because ondisk is NULL */
1131                 }
1132                 --hammer_count_nodes;
1133                 kfree(node, M_HAMMER);
1134         }
1135 }
1136
1137 /*
1138  * Flush passively cached B-Tree nodes associated with this buffer.
1139  * This is only called when the buffer is about to be destroyed, so
1140  * none of the nodes should have any references.  The buffer is locked.
1141  *
1142  * We may be interlocked with the buffer.
1143  */
1144 void
1145 hammer_flush_buffer_nodes(hammer_buffer_t buffer)
1146 {
1147         hammer_node_t node;
1148
1149         while ((node = TAILQ_FIRST(&buffer->clist)) != NULL) {
1150                 KKASSERT(node->ondisk == NULL);
1151
1152                 if (node->lock.refs == 0) {
1153                         hammer_ref(&node->lock);
1154                         node->flags |= HAMMER_NODE_FLUSH;
1155                         hammer_rel_node(node);
1156                 } else {
1157                         KKASSERT(node->loading != 0);
1158                         KKASSERT(node->buffer != NULL);
1159                         buffer = node->buffer;
1160                         node->buffer = NULL;
1161                         TAILQ_REMOVE(&buffer->clist, node, entry);
1162                         /* buffer is unreferenced because ondisk is NULL */
1163                 }
1164         }
1165 }
1166
1167
1168 /************************************************************************
1169  *                              ALLOCATORS                              *
1170  ************************************************************************/
1171
1172 /*
1173  * Allocate a B-Tree node.
1174  */
1175 hammer_node_t
1176 hammer_alloc_btree(hammer_transaction_t trans, int *errorp)
1177 {
1178         hammer_buffer_t buffer = NULL;
1179         hammer_node_t node = NULL;
1180         hammer_off_t node_offset;
1181
1182         node_offset = hammer_blockmap_alloc(trans, HAMMER_ZONE_BTREE_INDEX,
1183                                             sizeof(struct hammer_node_ondisk),
1184                                             errorp);
1185         if (*errorp == 0) {
1186                 node = hammer_get_node(trans->hmp, node_offset, 1, errorp);
1187                 hammer_modify_node_noundo(trans, node);
1188                 bzero(node->ondisk, sizeof(*node->ondisk));
1189                 hammer_modify_node_done(node);
1190         }
1191         if (buffer)
1192                 hammer_rel_buffer(buffer, 0);
1193         return(node);
1194 }
1195
1196 #if 0
1197
1198 /*
1199  * The returned buffers are already appropriately marked as being modified.
1200  * If the caller marks them again unnecessary undo records may be generated.
1201  *
1202  * In-band data is indicated by data_bufferp == NULL.  Pass a data_len of 0
1203  * for zero-fill (caller modifies data_len afterwords).
1204  *
1205  * If the caller is responsible for calling hammer_modify_*() prior to making
1206  * any additional modifications to either the returned record buffer or the
1207  * returned data buffer.
1208  */
1209 void *
1210 hammer_alloc_record(hammer_transaction_t trans,
1211                     hammer_off_t *rec_offp, u_int16_t rec_type,
1212                     struct hammer_buffer **rec_bufferp,
1213                     int32_t data_len, void **datap,
1214                     hammer_off_t *data_offp,
1215                     struct hammer_buffer **data_bufferp, int *errorp)
1216 {
1217         hammer_record_ondisk_t rec;
1218         hammer_off_t rec_offset;
1219         hammer_off_t data_offset;
1220         int32_t reclen;
1221
1222         if (datap)
1223                 *datap = NULL;
1224
1225         /*
1226          * Allocate the record
1227          */
1228         rec_offset = hammer_blockmap_alloc(trans, HAMMER_ZONE_RECORD_INDEX,
1229                                            HAMMER_RECORD_SIZE, errorp);
1230         if (*errorp)
1231                 return(NULL);
1232         if (data_offp)
1233                 *data_offp = 0;
1234
1235         /*
1236          * Allocate data
1237          */
1238         if (data_len) {
1239                 if (data_bufferp == NULL) {
1240                         switch(rec_type) {
1241                         case HAMMER_RECTYPE_DATA:
1242                                 reclen = offsetof(struct hammer_data_record,
1243                                                   data[0]);
1244                                 break;
1245                         case HAMMER_RECTYPE_DIRENTRY:
1246                                 reclen = offsetof(struct hammer_entry_record,
1247                                                   name[0]);
1248                                 break;
1249                         default:
1250                                 panic("hammer_alloc_record: illegal "
1251                                       "in-band data");
1252                                 /* NOT REACHED */
1253                                 reclen = 0;
1254                                 break;
1255                         }
1256                         KKASSERT(reclen + data_len <= HAMMER_RECORD_SIZE);
1257                         data_offset = rec_offset + reclen;
1258                 } else if (data_len < HAMMER_BUFSIZE) {
1259                         data_offset = hammer_blockmap_alloc(trans,
1260                                                 HAMMER_ZONE_SMALL_DATA_INDEX,
1261                                                 data_len, errorp);
1262                         *data_offp = data_offset;
1263                 } else {
1264                         data_offset = hammer_blockmap_alloc(trans,
1265                                                 HAMMER_ZONE_LARGE_DATA_INDEX,
1266                                                 data_len, errorp);
1267                         *data_offp = data_offset;
1268                 }
1269         } else {
1270                 data_offset = 0;
1271         }
1272         if (*errorp) {
1273                 hammer_blockmap_free(trans, rec_offset, HAMMER_RECORD_SIZE);
1274                 return(NULL);
1275         }
1276
1277         /*
1278          * Basic return values.
1279          *
1280          * Note that because this is a 'new' buffer, there is no need to
1281          * generate UNDO records for it.
1282          */
1283         *rec_offp = rec_offset;
1284         rec = hammer_bread(trans->hmp, rec_offset, errorp, rec_bufferp);
1285         hammer_modify_buffer(trans, *rec_bufferp, NULL, 0);
1286         bzero(rec, sizeof(*rec));
1287         KKASSERT(*errorp == 0);
1288         rec->base.data_off = data_offset;
1289         rec->base.data_len = data_len;
1290         hammer_modify_buffer_done(*rec_bufferp);
1291
1292         if (data_bufferp) {
1293                 if (data_len) {
1294                         *datap = hammer_bread(trans->hmp, data_offset, errorp,
1295                                               data_bufferp);
1296                         KKASSERT(*errorp == 0);
1297                 } else {
1298                         *datap = NULL;
1299                 }
1300         } else if (data_len) {
1301                 KKASSERT(data_offset + data_len - rec_offset <=
1302                          HAMMER_RECORD_SIZE);
1303                 if (datap) {
1304                         *datap = (void *)((char *)rec +
1305                                           (int32_t)(data_offset - rec_offset));
1306                 }
1307         } else {
1308                 KKASSERT(datap == NULL);
1309         }
1310         KKASSERT(*errorp == 0);
1311         return(rec);
1312 }
1313
1314 #endif
1315
1316 /*
1317  * Allocate data.  If the address of a data buffer is supplied then
1318  * any prior non-NULL *data_bufferp will be released and *data_bufferp
1319  * will be set to the related buffer.  The caller must release it when
1320  * finally done.  The initial *data_bufferp should be set to NULL by
1321  * the caller.
1322  *
1323  * The caller is responsible for making hammer_modify*() calls on the
1324  * *data_bufferp.
1325  */
1326 void *
1327 hammer_alloc_data(hammer_transaction_t trans, int32_t data_len,
1328                   hammer_off_t *data_offsetp,
1329                   struct hammer_buffer **data_bufferp, int *errorp)
1330 {
1331         void *data;
1332
1333         /*
1334          * Allocate data
1335          */
1336         if (data_len) {
1337                 if (data_len < HAMMER_BUFSIZE) {
1338                         *data_offsetp = hammer_blockmap_alloc(trans,
1339                                                 HAMMER_ZONE_SMALL_DATA_INDEX,
1340                                                 data_len, errorp);
1341                 } else {
1342                         *data_offsetp = hammer_blockmap_alloc(trans,
1343                                                 HAMMER_ZONE_LARGE_DATA_INDEX,
1344                                                 data_len, errorp);
1345                 }
1346         } else {
1347                 *data_offsetp = 0;
1348         }
1349         if (*errorp == 0 && data_bufferp) {
1350                 if (data_len) {
1351                         data = hammer_bread(trans->hmp, *data_offsetp, errorp,
1352                                             data_bufferp);
1353                         KKASSERT(*errorp == 0);
1354                 } else {
1355                         data = NULL;
1356                 }
1357         } else {
1358                 data = NULL;
1359         }
1360         KKASSERT(*errorp == 0);
1361         return(data);
1362 }
1363
1364 /*
1365  * Sync dirty buffers to the media and clean-up any loose ends.
1366  */
1367 static int hammer_sync_scan1(struct mount *mp, struct vnode *vp, void *data);
1368 static int hammer_sync_scan2(struct mount *mp, struct vnode *vp, void *data);
1369
1370 int
1371 hammer_sync_hmp(hammer_mount_t hmp, int waitfor)
1372 {
1373         struct hammer_sync_info info;
1374
1375         info.error = 0;
1376         info.waitfor = waitfor;
1377
1378         vmntvnodescan(hmp->mp, VMSC_GETVP|VMSC_NOWAIT,
1379                       hammer_sync_scan1, hammer_sync_scan2, &info);
1380         if (waitfor == MNT_WAIT)
1381                 hammer_flusher_sync(hmp);
1382         else
1383                 hammer_flusher_async(hmp);
1384
1385         return(info.error);
1386 }
1387
1388 static int
1389 hammer_sync_scan1(struct mount *mp, struct vnode *vp, void *data)
1390 {
1391         struct hammer_inode *ip;
1392
1393         ip = VTOI(vp);
1394         if (vp->v_type == VNON || ip == NULL ||
1395             ((ip->flags & HAMMER_INODE_MODMASK) == 0 &&
1396              RB_EMPTY(&vp->v_rbdirty_tree))) {
1397                 return(-1);
1398         }
1399         return(0);
1400 }
1401
1402 static int
1403 hammer_sync_scan2(struct mount *mp, struct vnode *vp, void *data)
1404 {
1405         struct hammer_sync_info *info = data;
1406         struct hammer_inode *ip;
1407         int error;
1408
1409         ip = VTOI(vp);
1410         if (vp->v_type == VNON || vp->v_type == VBAD ||
1411             ((ip->flags & HAMMER_INODE_MODMASK) == 0 &&
1412              RB_EMPTY(&vp->v_rbdirty_tree))) {
1413                 return(0);
1414         }
1415         error = VOP_FSYNC(vp, info->waitfor);
1416         if (error)
1417                 info->error = error;
1418         return(0);
1419 }
1420