sys/vfs/hammer/hammer_volume.c

   1 /*
   2  * Copyright (c) 2009 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> and
   6  * Michael Neumann <mneumann@ntecs.de>
   7  *
   8  * Redistribution and use in source and binary forms, with or without
   9  * modification, are permitted provided that the following conditions
  10  * are met:
  11  *
  12  * 1. Redistributions of source code must retain the above copyright
  13  *    notice, this list of conditions and the following disclaimer.
  14  * 2. Redistributions in binary form must reproduce the above copyright
  15  *    notice, this list of conditions and the following disclaimer in
  16  *    the documentation and/or other materials provided with the
  17  *    distribution.
  18  * 3. Neither the name of The DragonFly Project nor the names of its
  19  *    contributors may be used to endorse or promote products derived
  20  *    from this software without specific, prior written permission.
  21  *
  22  * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
  23  * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
  24  * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
  25  * FOR A PARTICULAR PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE
  26  * COPYRIGHT HOLDERS OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
  27  * INCIDENTAL, SPECIAL, EXEMPLARY OR CONSEQUENTIAL DAMAGES (INCLUDING,
  28  * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
  29  * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
  30  * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
  31  * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
  32  * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  33  * SUCH DAMAGE.
  34  *
  35  */
  36
  37 #include "hammer.h"
  38 #include <sys/fcntl.h>
  39 #include <sys/nlookup.h>
  40 #include <sys/buf.h>
  41
  42 static int
  43 hammer_setup_device(struct vnode **devvpp, const char *dev_path, int ronly);
  44
  45 static void
  46 hammer_close_device(struct vnode **devvpp, int ronly);
  47
  48 static int
  49 hammer_format_volume_header(struct hammer_mount *hmp, struct vnode *devvp,
  50         const char *vol_name, int vol_no, int vol_count,
  51         int64_t vol_size, int64_t boot_area_size, int64_t mem_area_size);
  52
  53 static uint64_t
  54 hammer_format_freemap(hammer_transaction_t trans, hammer_volume_t volume);
  55
  56 static int
  57 hammer_free_freemap(hammer_transaction_t trans, hammer_volume_t volume);
  58
  59
  60 int
  61 hammer_ioc_volume_add(hammer_transaction_t trans, hammer_inode_t ip,
  62                 struct hammer_ioc_volume *ioc)
  63 {
  64         struct hammer_mount *hmp = trans->hmp;
  65         struct mount *mp = hmp->mp;
  66         hammer_volume_t volume;
  67         int error;
  68
  69         if (mp->mnt_flag & MNT_RDONLY) {
  70                 kprintf("Cannot add volume to read-only HAMMER filesystem\n");
  71                 return (EINVAL);
  72         }
  73
  74         if (hmp->nvolumes + 1 >= HAMMER_MAX_VOLUMES) {
  75                 kprintf("Max number of HAMMER volumes exceeded\n");
  76                 return (EINVAL);
  77         }
  78
  79         /*
  80          * Find an unused volume number.
  81          */
  82         int free_vol_no = 0;
  83         while (free_vol_no < HAMMER_MAX_VOLUMES &&
  84                RB_LOOKUP(hammer_vol_rb_tree, &hmp->rb_vols_root, free_vol_no)) {
  85                 ++free_vol_no;
  86         }
  87         if (free_vol_no >= HAMMER_MAX_VOLUMES) {
  88                 kprintf("Max number of HAMMER volumes exceeded\n");
  89                 return (EINVAL);
  90         }
  91
  92         struct vnode *devvp = NULL;
  93         error = hammer_setup_device(&devvp, ioc->device_name, 0);
  94         if (error)
  95                 goto end;
  96         KKASSERT(devvp);
  97         error = hammer_format_volume_header(
  98                 hmp,
  99                 devvp,
 100                 hmp->rootvol->ondisk->vol_name,
 101                 free_vol_no,
 102                 hmp->nvolumes+1,
 103                 ioc->vol_size,
 104                 ioc->boot_area_size,
 105                 ioc->mem_area_size);
 106         hammer_close_device(&devvp, 0);
 107         if (error)
 108                 goto end;
 109
 110         error = hammer_install_volume(hmp, ioc->device_name, NULL);
 111         if (error)
 112                 goto end;
 113
 114         hammer_sync_lock_sh(trans);
 115         hammer_lock_ex(&hmp->blkmap_lock);
 116
 117         ++hmp->nvolumes;
 118
 119         /*
 120          * Set each volumes new value of the vol_count field.
 121          */
 122         for (int vol_no = 0; vol_no < HAMMER_MAX_VOLUMES; ++vol_no) {
 123                 if (vol_no == free_vol_no)
 124                         continue;
 125
 126                 volume = hammer_get_volume(hmp, vol_no, &error);
 127                 if (volume == NULL && error == ENOENT) {
 128                         /*
 129                          * Skip unused volume numbers
 130                          */
 131                         error = 0;
 132                         continue;
 133                 }
 134                 KKASSERT(volume != NULL && error == 0);
 135                 hammer_modify_volume_field(trans, volume, vol_count);
 136                 volume->ondisk->vol_count = hmp->nvolumes;
 137                 hammer_modify_volume_done(volume);
 138                 hammer_rel_volume(volume, 0);
 139         }
 140
 141         volume = hammer_get_volume(hmp, free_vol_no, &error);
 142         KKASSERT(volume != NULL && error == 0);
 143
 144         uint64_t total_free_bigblocks =
 145                 hammer_format_freemap(trans, volume);
 146
 147         /*
 148          * Increase the total number of bigblocks
 149          */
 150         hammer_modify_volume_field(trans, trans->rootvol,
 151                 vol0_stat_bigblocks);
 152         trans->rootvol->ondisk->vol0_stat_bigblocks += total_free_bigblocks;
 153         hammer_modify_volume_done(trans->rootvol);
 154
 155         /*
 156          * Increase the number of free bigblocks
 157          * (including the copy in hmp)
 158          */
 159         hammer_modify_volume_field(trans, trans->rootvol,
 160                 vol0_stat_freebigblocks);
 161         trans->rootvol->ondisk->vol0_stat_freebigblocks += total_free_bigblocks;
 162         hmp->copy_stat_freebigblocks =
 163                 trans->rootvol->ondisk->vol0_stat_freebigblocks;
 164         hammer_modify_volume_done(trans->rootvol);
 165
 166         hammer_rel_volume(volume, 0);
 167
 168         hammer_unlock(&hmp->blkmap_lock);
 169         hammer_sync_unlock(trans);
 170
 171 end:
 172         if (error)
 173                 kprintf("An error occurred: %d\n", error);
 174         return (error);
 175 }
 176
 177
 178 /*
 179  * Remove a volume.
 180  */
 181 int
 182 hammer_ioc_volume_del(hammer_transaction_t trans, hammer_inode_t ip,
 183                 struct hammer_ioc_volume *ioc)
 184 {
 185         struct hammer_mount *hmp = trans->hmp;
 186         struct mount *mp = hmp->mp;
 187         hammer_volume_t volume;
 188         int error = 0;
 189
 190         if (mp->mnt_flag & MNT_RDONLY) {
 191                 kprintf("Cannot del volume from read-only HAMMER filesystem\n");
 192                 return (EINVAL);
 193         }
 194
 195
 196         volume = NULL;
 197
 198         /*
 199          * find volume by volname
 200          */
 201         for (int vol_no = 0; vol_no < HAMMER_MAX_VOLUMES; ++vol_no) {
 202                 volume = hammer_get_volume(hmp, vol_no, &error);
 203                 if (volume == NULL && error == ENOENT) {
 204                         /*
 205                          * Skip unused volume numbers
 206                          */
 207                         error = 0;
 208                         continue;
 209                 }
 210                 KKASSERT(volume != NULL && error == 0);
 211                 if (strcmp(volume->vol_name, ioc->device_name) == 0) {
 212                         break;
 213                 }
 214                 volume = NULL;
 215         }
 216
 217         if (!volume) {
 218                 kprintf("Couldn't find volume\n");
 219                 return (EINVAL);
 220         }
 221
 222         if (volume == trans->rootvol) {
 223                 kprintf("Cannot remove root-volume\n");
 224                 hammer_rel_volume(volume, 0);
 225                 return (EINVAL);
 226         }
 227
 228         /*
 229          *
 230          */
 231
 232         hmp->volume_to_remove = volume->vol_no;
 233
 234         struct hammer_ioc_reblock reblock;
 235         bzero(&reblock, sizeof(reblock));
 236
 237         reblock.key_beg.localization = HAMMER_MIN_LOCALIZATION;
 238         reblock.key_beg.obj_id = HAMMER_MIN_OBJID;
 239         reblock.key_end.localization = HAMMER_MAX_LOCALIZATION;
 240         reblock.key_end.obj_id = HAMMER_MAX_OBJID;
 241         //reblock.head.flags = flags & HAMMER_IOC_DO_FLAGS;
 242         reblock.free_level = HAMMER_LARGEBLOCK_SIZE;
 243         reblock.free_level = 0;
 244
 245         error = hammer_ioc_reblock(trans, ip, &reblock);
 246
 247         if (error) {
 248                 kprintf("reblock failed: %d\n", error);
 249                 hmp->volume_to_remove = -1;
 250                 hammer_rel_volume(volume, 0);
 251                 return (error);
 252         }
 253
 254         hammer_sync_lock_sh(trans);
 255         hammer_lock_ex(&hmp->blkmap_lock);
 256
 257         error = hammer_free_freemap(trans, volume);
 258         if (error) {
 259                 kprintf("Failed to free volume\n");
 260                 hmp->volume_to_remove = -1;
 261                 hammer_rel_volume(volume, 0);
 262                 hammer_unlock(&hmp->blkmap_lock);
 263                 hammer_sync_unlock(trans);
 264                 return (error);
 265         }
 266
 267         hmp->volume_to_remove = -1;
 268         hammer_rel_volume(volume, 1);
 269
 270         /* XXX: unload volume! */
 271         /*error = hammer_unload_volume(volume, NULL);
 272         if (error == -1) {
 273                 kprintf("Failed to unload volume\n");
 274                 hammer_unlock(&hmp->blkmap_lock);
 275                 hammer_sync_unlock(trans);
 276                 return (error);
 277         }*/
 278
 279         --hmp->nvolumes;
 280
 281         /*
 282          * Set each volume's new value of the vol_count field.
 283          */
 284         for (int vol_no = 0; vol_no < HAMMER_MAX_VOLUMES; ++vol_no) {
 285                 volume = hammer_get_volume(hmp, vol_no, &error);
 286                 if (volume == NULL && error == ENOENT) {
 287                         /*
 288                          * Skip unused volume numbers
 289                          */
 290                         error = 0;
 291                         continue;
 292                 }
 293                 KKASSERT(volume != NULL && error == 0);
 294                 hammer_modify_volume_field(trans, volume, vol_count);
 295                 volume->ondisk->vol_count = hmp->nvolumes;
 296                 hammer_modify_volume_done(volume);
 297                 hammer_rel_volume(volume, 0);
 298         }
 299
 300         hammer_unlock(&hmp->blkmap_lock);
 301         hammer_sync_unlock(trans);
 302
 303         return (0);
 304 }
 305
 306
 307 /*
 308  * Iterate over all usable L1 entries of the volume and
 309  * the corresponding L2 entries.
 310  */
 311 static int
 312 hammer_iterate_l1l2_entries(hammer_transaction_t trans, hammer_volume_t volume,
 313         int (*callback)(hammer_transaction_t, hammer_buffer_t *,
 314                 struct hammer_blockmap_layer1*, struct hammer_blockmap_layer2 *,
 315                 hammer_off_t, int, void *),
 316         void *data)
 317 {
 318         struct hammer_mount *hmp = trans->hmp;
 319         hammer_blockmap_t freemap = &hmp->blockmap[HAMMER_ZONE_FREEMAP_INDEX];
 320         hammer_buffer_t buffer = NULL;
 321         int error = 0;
 322
 323         hammer_off_t phys_off;
 324         hammer_off_t block_off;
 325         hammer_off_t layer1_off;
 326         hammer_off_t layer2_off;
 327         hammer_off_t aligned_buf_end_off;
 328         struct hammer_blockmap_layer1 *layer1;
 329         struct hammer_blockmap_layer2 *layer2;
 330
 331         /*
 332          * Calculate the usable size of the volume, which
 333          * must be aligned at a bigblock (8 MB) boundary.
 334          */
 335         aligned_buf_end_off = (HAMMER_ENCODE_RAW_BUFFER(volume->ondisk->vol_no,
 336                 (volume->ondisk->vol_buf_end - volume->ondisk->vol_buf_beg)
 337                 & ~HAMMER_LARGEBLOCK_MASK64));
 338
 339         /*
 340          * Iterate the volume's address space in chunks of 4 TB, where each
 341          * chunk consists of at least one physically available 8 MB bigblock.
 342          *
 343          * For each chunk we need one L1 entry and one L2 bigblock.
 344          * We use the first bigblock of each chunk as L2 block.
 345          */
 346         for (phys_off = HAMMER_ENCODE_RAW_BUFFER(volume->ondisk->vol_no, 0);
 347              phys_off < aligned_buf_end_off;
 348              phys_off += HAMMER_BLOCKMAP_LAYER2) {
 349                 for (block_off = 0;
 350                      block_off < HAMMER_BLOCKMAP_LAYER2;
 351                      block_off += HAMMER_LARGEBLOCK_SIZE) {
 352                         layer2_off = phys_off +
 353                                 HAMMER_BLOCKMAP_LAYER2_OFFSET(block_off);
 354                         layer2 = hammer_bread(hmp, layer2_off, &error,
 355                                                 &buffer);
 356                         if (error)
 357                                 goto end;
 358
 359                         int zone;
 360                         if (block_off == 0) {
 361                                 /*
 362                                  * The first entry represents the L2 bigblock
 363                                  * itself.
 364                                  */
 365                                 zone = HAMMER_ZONE_FREEMAP_INDEX;
 366                         } else if (phys_off + block_off < aligned_buf_end_off) {
 367                                 /*
 368                                  * Available bigblock
 369                                  */
 370                                 zone = 0;
 371                         } else {
 372                                 /*
 373                                  * Bigblock outside of physically available
 374                                  * space
 375                                  */
 376                                 zone = HAMMER_ZONE_UNAVAIL_INDEX;
 377                         }
 378
 379                         error = callback(trans, &buffer, NULL, layer2, 0, zone,
 380                                         data);
 381                         if (error)
 382                                 goto end;
 383                 }
 384
 385                 layer1_off = freemap->phys_offset +
 386                                 HAMMER_BLOCKMAP_LAYER1_OFFSET(phys_off);
 387                 layer1 = hammer_bread(hmp, layer1_off, &error, &buffer);
 388                 if (error)
 389                         goto end;
 390
 391                 error = callback(trans, &buffer, layer1, NULL, phys_off, 0,
 392                                 data);
 393                 if (error)
 394                         goto end;
 395         }
 396
 397 end:
 398         if (buffer) {
 399                 hammer_rel_buffer(buffer, 0);
 400                 buffer = NULL;
 401         }
 402
 403         return error;
 404 }
 405
 406 struct format_bigblock_stat {
 407         uint64_t total_free_bigblocks;
 408         uint64_t free_bigblocks;
 409 };
 410
 411 static int
 412 format_callback(hammer_transaction_t trans, hammer_buffer_t *bufferp,
 413         struct hammer_blockmap_layer1 *layer1,
 414         struct hammer_blockmap_layer2 *layer2,
 415         hammer_off_t phys_off,
 416         int layer2_zone,
 417         void *data)
 418 {
 419         struct format_bigblock_stat *stat = (struct format_bigblock_stat*)data;
 420
 421         if (layer1) {
 422                 KKASSERT(layer1->phys_offset == HAMMER_BLOCKMAP_UNAVAIL);
 423
 424                 hammer_modify_buffer(trans, *bufferp, layer1, sizeof(*layer1));
 425                 bzero(layer1, sizeof(layer1));
 426                 layer1->phys_offset = phys_off;
 427                 layer1->blocks_free = stat->free_bigblocks;
 428                 layer1->layer1_crc = crc32(layer1, HAMMER_LAYER1_CRCSIZE);
 429                 hammer_modify_buffer_done(*bufferp);
 430
 431                 stat->total_free_bigblocks += stat->free_bigblocks;
 432                 stat->free_bigblocks = 0; /* reset */
 433         } else if (layer2) {
 434                 hammer_modify_buffer(trans, *bufferp, layer2, sizeof(*layer2));
 435                 bzero(layer2, sizeof(*layer2));
 436
 437                 layer2->zone = layer2_zone;
 438
 439                 switch (layer2->zone) {
 440                 case HAMMER_ZONE_FREEMAP_INDEX:
 441                         /*
 442                          * The first entry represents the L2 bigblock itself.
 443                          */
 444                         layer2->append_off = HAMMER_LARGEBLOCK_SIZE;
 445                         layer2->bytes_free = 0;
 446                         break;
 447
 448                 case 0:
 449                         /*
 450                          * Available bigblock
 451                          */
 452                         layer2->append_off = 0;
 453                         layer2->bytes_free = HAMMER_LARGEBLOCK_SIZE;
 454                         ++stat->free_bigblocks;
 455                         break;
 456
 457                 case HAMMER_ZONE_UNAVAIL_INDEX:
 458                         /*
 459                          * Bigblock outside of physically available space
 460                          */
 461                         layer2->append_off = HAMMER_LARGEBLOCK_SIZE;
 462                         layer2->bytes_free = 0;
 463                         break;
 464                 default:
 465                         KKASSERT(0);
 466                 }
 467
 468                 layer2->entry_crc = crc32(layer2, HAMMER_LAYER2_CRCSIZE);
 469                 hammer_modify_buffer_done(*bufferp);
 470         } else {
 471                 KKASSERT(0);
 472         }
 473
 474         return 0;
 475 }
 476
 477 static uint64_t
 478 hammer_format_freemap(hammer_transaction_t trans, hammer_volume_t volume)
 479 {
 480         int error = 0;
 481
 482         struct format_bigblock_stat stat;
 483         stat.total_free_bigblocks = 0;
 484         stat.free_bigblocks = 0;
 485
 486         error = hammer_iterate_l1l2_entries(trans, volume, format_callback,
 487                                         (void*)&stat);
 488         KKASSERT(error == 0);
 489
 490         return stat.total_free_bigblocks;
 491 }
 492
 493 static int
 494 free_callback(hammer_transaction_t trans, hammer_buffer_t *bufferp,
 495         struct hammer_blockmap_layer1 *layer1,
 496         struct hammer_blockmap_layer2 *layer2,
 497         hammer_off_t phys_off,
 498         int layer2_zone,
 499         void *data __unused)
 500 {
 501         if (layer1) {
 502                 /*
 503                  * Free the L1 entry
 504                  */
 505                 hammer_modify_buffer(trans, *bufferp, layer1, sizeof(*layer1));
 506                 bzero(layer1, sizeof(layer1));
 507                 layer1->phys_offset = HAMMER_BLOCKMAP_UNAVAIL;
 508                 layer1->layer1_crc = crc32(layer1, HAMMER_LAYER1_CRCSIZE);
 509                 hammer_modify_buffer_done(*bufferp);
 510
 511                 return 0;
 512         } else if (layer2) {
 513                 switch (layer2_zone) {
 514                 case HAMMER_ZONE_FREEMAP_INDEX:
 515                 case HAMMER_ZONE_UNAVAIL_INDEX:
 516                         return 0;
 517                 case 0:
 518                         if (layer2->append_off == 0 &&
 519                             layer2->bytes_free == HAMMER_LARGEBLOCK_SIZE) {
 520                                 return 0;
 521                         } else {
 522                                 return EINVAL; /* FIXME */
 523                         }
 524                 default:
 525                         return EINVAL;  /* FIXME */
 526                 }
 527         } else {
 528                 KKASSERT(0);
 529         }
 530
 531         return EINVAL;
 532 }
 533
 534 static int
 535 hammer_free_freemap(hammer_transaction_t trans, hammer_volume_t volume)
 536 {
 537         return hammer_iterate_l1l2_entries(trans, volume, free_callback, NULL);
 538 }
 539
 540 /************************************************************************
 541  *                              MISC                                    *
 542  ************************************************************************
 543  */
 544
 545 static int
 546 hammer_setup_device(struct vnode **devvpp, const char *dev_path, int ronly)
 547 {
 548         int error;
 549         struct nlookupdata nd;
 550
 551         /*
 552          * Get the device vnode
 553          */
 554         if (*devvpp == NULL) {
 555                 error = nlookup_init(&nd, dev_path, UIO_SYSSPACE, NLC_FOLLOW);
 556                 if (error == 0)
 557                         error = nlookup(&nd);
 558                 if (error == 0)
 559                         error = cache_vref(&nd.nl_nch, nd.nl_cred, devvpp);
 560                 nlookup_done(&nd);
 561         } else {
 562                 error = 0;
 563         }
 564
 565         if (error == 0) {
 566                 if (vn_isdisk(*devvpp, &error)) {
 567                         error = vfs_mountedon(*devvpp);
 568                 }
 569         }
 570         if (error == 0 && vcount(*devvpp) > 0)
 571                 error = EBUSY;
 572         if (error == 0) {
 573                 vn_lock(*devvpp, LK_EXCLUSIVE | LK_RETRY);
 574                 error = vinvalbuf(*devvpp, V_SAVE, 0, 0);
 575                 if (error == 0) {
 576                         error = VOP_OPEN(*devvpp,
 577                                          (ronly ? FREAD : FREAD|FWRITE),
 578                                          FSCRED, NULL);
 579                 }
 580                 vn_unlock(*devvpp);
 581         }
 582         if (error && *devvpp) {
 583                 vrele(*devvpp);
 584                 *devvpp = NULL;
 585         }
 586         return (error);
 587 }
 588
 589 static void
 590 hammer_close_device(struct vnode **devvpp, int ronly)
 591 {
 592         VOP_CLOSE(*devvpp, (ronly ? FREAD : FREAD|FWRITE));
 593         if (*devvpp) {
 594                 vinvalbuf(*devvpp, ronly ? 0 : V_SAVE, 0, 0);
 595                 vrele(*devvpp);
 596                 *devvpp = NULL;
 597         }
 598 }
 599
 600 static int
 601 hammer_format_volume_header(struct hammer_mount *hmp, struct vnode *devvp,
 602         const char *vol_name, int vol_no, int vol_count,
 603         int64_t vol_size, int64_t boot_area_size, int64_t mem_area_size)
 604 {
 605         struct buf *bp = NULL;
 606         struct hammer_volume_ondisk *ondisk;
 607         int error;
 608
 609         /*
 610          * Extract the volume number from the volume header and do various
 611          * sanity checks.
 612          */
 613         KKASSERT(HAMMER_BUFSIZE >= sizeof(struct hammer_volume_ondisk));
 614         error = bread(devvp, 0LL, HAMMER_BUFSIZE, &bp);
 615         if (error || bp->b_bcount < sizeof(struct hammer_volume_ondisk))
 616                 goto late_failure;
 617
 618         ondisk = (struct hammer_volume_ondisk*) bp->b_data;
 619
 620         /*
 621          * Note that we do NOT allow to use a device that contains
 622          * a valid HAMMER signature. It has to be cleaned up with dd
 623          * before.
 624          */
 625         if (ondisk->vol_signature == HAMMER_FSBUF_VOLUME) {
 626                 kprintf("hammer_volume_add: Formatting of valid HAMMER volume "
 627                         "%s denied. Erase with dd!\n", vol_name);
 628                 error = EFTYPE;
 629                 goto late_failure;
 630         }
 631
 632         bzero(ondisk, sizeof(struct hammer_volume_ondisk));
 633         ksnprintf(ondisk->vol_name, sizeof(ondisk->vol_name), "%s", vol_name);
 634         ondisk->vol_fstype = hmp->rootvol->ondisk->vol_fstype;
 635         ondisk->vol_signature = HAMMER_FSBUF_VOLUME;
 636         ondisk->vol_fsid = hmp->fsid;
 637         ondisk->vol_rootvol = hmp->rootvol->vol_no;
 638         ondisk->vol_no = vol_no;
 639         ondisk->vol_count = vol_count;
 640         ondisk->vol_version = hmp->version;
 641
 642         /*
 643          * Reserve space for (future) header junk, setup our poor-man's
 644          * bigblock allocator.
 645          */
 646         int64_t vol_alloc = HAMMER_BUFSIZE * 16;
 647
 648         ondisk->vol_bot_beg = vol_alloc;
 649         vol_alloc += boot_area_size;
 650         ondisk->vol_mem_beg = vol_alloc;
 651         vol_alloc += mem_area_size;
 652
 653         /*
 654          * The remaining area is the zone 2 buffer allocation area.  These
 655          * buffers
 656          */
 657         ondisk->vol_buf_beg = vol_alloc;
 658         ondisk->vol_buf_end = vol_size & ~(int64_t)HAMMER_BUFMASK;
 659
 660         if (ondisk->vol_buf_end < ondisk->vol_buf_beg) {
 661                 kprintf("volume %d %s is too small to hold the volume header",
 662                      ondisk->vol_no, ondisk->vol_name);
 663                 error = EFTYPE;
 664                 goto late_failure;
 665         }
 666
 667         ondisk->vol_nblocks = (ondisk->vol_buf_end - ondisk->vol_buf_beg) /
 668                               HAMMER_BUFSIZE;
 669         ondisk->vol_blocksize = HAMMER_BUFSIZE;
 670
 671         /*
 672          * Write volume header to disk
 673          */
 674         error = bwrite(bp);
 675         bp = NULL;
 676
 677 late_failure:
 678         if (bp)
 679                 brelse(bp);
 680         return (error);
 681 }