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 #include <sys/buf2.h>
  43
  44 static int
  45 hammer_setup_device(struct vnode **devvpp, const char *dev_path, int ronly);
  46
  47 static void
  48 hammer_close_device(struct vnode **devvpp, int ronly);
  49
  50 static int
  51 hammer_format_volume_header(struct hammer_mount *hmp, struct vnode *devvp,
  52         const char *vol_name, int vol_no, int vol_count,
  53         int64_t vol_size, int64_t boot_area_size, int64_t mem_area_size);
  54
  55 static int
  56 hammer_clear_volume_header(struct vnode *devvp);
  57
  58 struct bigblock_stat {
  59         uint64_t total_bigblocks;
  60         uint64_t total_free_bigblocks;
  61         uint64_t counter;
  62 };
  63
  64 static int
  65 hammer_format_freemap(hammer_transaction_t trans, hammer_volume_t volume,
  66         struct bigblock_stat *stat);
  67
  68 static int
  69 hammer_free_freemap(hammer_transaction_t trans, hammer_volume_t volume,
  70         struct bigblock_stat *stat);
  71
  72 int
  73 hammer_ioc_volume_add(hammer_transaction_t trans, hammer_inode_t ip,
  74                 struct hammer_ioc_volume *ioc)
  75 {
  76         struct hammer_mount *hmp = trans->hmp;
  77         struct mount *mp = hmp->mp;
  78         hammer_volume_t volume;
  79         int error;
  80
  81         if (mp->mnt_flag & MNT_RDONLY) {
  82                 kprintf("Cannot add volume to read-only HAMMER filesystem\n");
  83                 return (EINVAL);
  84         }
  85
  86         if (hmp->nvolumes >= HAMMER_MAX_VOLUMES) {
  87                 kprintf("Max number of HAMMER volumes exceeded\n");
  88                 return (EINVAL);
  89         }
  90
  91         if (hammer_lock_ex_try(&hmp->volume_lock) != 0) {
  92                 kprintf("Another volume operation is in progress!\n");
  93                 return (EAGAIN);
  94         }
  95
  96         /*
  97          * Find an unused volume number.
  98          */
  99         int free_vol_no = 0;
 100         while (free_vol_no < HAMMER_MAX_VOLUMES &&
 101                RB_LOOKUP(hammer_vol_rb_tree, &hmp->rb_vols_root, free_vol_no)) {
 102                 ++free_vol_no;
 103         }
 104         if (free_vol_no >= HAMMER_MAX_VOLUMES) {
 105                 kprintf("Max number of HAMMER volumes exceeded\n");
 106                 hammer_unlock(&hmp->volume_lock);
 107                 return (EINVAL);
 108         }
 109
 110         struct vnode *devvp = NULL;
 111         error = hammer_setup_device(&devvp, ioc->device_name, 0);
 112         if (error)
 113                 goto end;
 114         KKASSERT(devvp);
 115         error = hammer_format_volume_header(
 116                 hmp,
 117                 devvp,
 118                 hmp->rootvol->ondisk->vol_name,
 119                 free_vol_no,
 120                 hmp->nvolumes+1,
 121                 ioc->vol_size,
 122                 ioc->boot_area_size,
 123                 ioc->mem_area_size);
 124         hammer_close_device(&devvp, 0);
 125         if (error)
 126                 goto end;
 127
 128         error = hammer_install_volume(hmp, ioc->device_name, NULL);
 129         if (error)
 130                 goto end;
 131
 132         hammer_sync_lock_sh(trans);
 133         hammer_lock_ex(&hmp->blkmap_lock);
 134
 135         ++hmp->nvolumes;
 136
 137         /*
 138          * Set each volumes new value of the vol_count field.
 139          */
 140         for (int vol_no = 0; vol_no < HAMMER_MAX_VOLUMES; ++vol_no) {
 141                 volume = hammer_get_volume(hmp, vol_no, &error);
 142                 if (volume == NULL && error == ENOENT) {
 143                         /*
 144                          * Skip unused volume numbers
 145                          */
 146                         error = 0;
 147                         continue;
 148                 }
 149                 KKASSERT(volume != NULL && error == 0);
 150                 hammer_modify_volume_field(trans, volume, vol_count);
 151                 volume->ondisk->vol_count = hmp->nvolumes;
 152                 hammer_modify_volume_done(volume);
 153
 154                 /*
 155                  * Only changes to the header of the root volume
 156                  * are automatically flushed to disk. For all
 157                  * other volumes that we modify we do it here.
 158                  *
 159                  * No interlock is needed, volume buffers are not
 160                  * messed with by bioops.
 161                  */
 162                 if (volume != trans->rootvol && volume->io.modified) {
 163                         hammer_crc_set_volume(volume->ondisk);
 164                         hammer_io_flush(&volume->io, 0);
 165                 }
 166
 167                 hammer_rel_volume(volume, 0);
 168         }
 169
 170         volume = hammer_get_volume(hmp, free_vol_no, &error);
 171         KKASSERT(volume != NULL && error == 0);
 172
 173         struct bigblock_stat stat;
 174         error = hammer_format_freemap(trans, volume, &stat);
 175         KKASSERT(error == 0);
 176
 177         /*
 178          * Increase the total number of big-blocks and update stat/vstat totals.
 179          */
 180         hammer_modify_volume_field(trans, trans->rootvol,
 181                 vol0_stat_bigblocks);
 182         trans->rootvol->ondisk->vol0_stat_bigblocks += stat.total_bigblocks;
 183         hammer_modify_volume_done(trans->rootvol);
 184         /*
 185          * Big-block count changed so recompute the total number of blocks.
 186          */
 187         mp->mnt_stat.f_blocks = trans->rootvol->ondisk->vol0_stat_bigblocks *
 188             (HAMMER_BIGBLOCK_SIZE / HAMMER_BUFSIZE);
 189         mp->mnt_vstat.f_blocks = trans->rootvol->ondisk->vol0_stat_bigblocks *
 190             (HAMMER_BIGBLOCK_SIZE / HAMMER_BUFSIZE);
 191
 192         /*
 193          * Increase the number of free big-blocks
 194          * (including the copy in hmp)
 195          */
 196         hammer_modify_volume_field(trans, trans->rootvol,
 197                 vol0_stat_freebigblocks);
 198         trans->rootvol->ondisk->vol0_stat_freebigblocks += stat.total_free_bigblocks;
 199         hmp->copy_stat_freebigblocks =
 200                 trans->rootvol->ondisk->vol0_stat_freebigblocks;
 201         hammer_modify_volume_done(trans->rootvol);
 202
 203         hammer_rel_volume(volume, 0);
 204
 205         hammer_unlock(&hmp->blkmap_lock);
 206         hammer_sync_unlock(trans);
 207
 208         KKASSERT(error == 0);
 209 end:
 210         hammer_unlock(&hmp->volume_lock);
 211         if (error)
 212                 kprintf("An error occurred: %d\n", error);
 213         return (error);
 214 }
 215
 216
 217 /*
 218  * Remove a volume.
 219  */
 220 int
 221 hammer_ioc_volume_del(hammer_transaction_t trans, hammer_inode_t ip,
 222                 struct hammer_ioc_volume *ioc)
 223 {
 224         struct hammer_mount *hmp = trans->hmp;
 225         struct mount *mp = hmp->mp;
 226         hammer_volume_t volume;
 227         int error = 0;
 228
 229         if (mp->mnt_flag & MNT_RDONLY) {
 230                 kprintf("Cannot del volume from read-only HAMMER filesystem\n");
 231                 return (EINVAL);
 232         }
 233
 234         if (hammer_lock_ex_try(&hmp->volume_lock) != 0) {
 235                 kprintf("Another volume operation is in progress!\n");
 236                 return (EAGAIN);
 237         }
 238
 239         volume = NULL;
 240
 241         /*
 242          * find volume by volname
 243          */
 244         for (int vol_no = 0; vol_no < HAMMER_MAX_VOLUMES; ++vol_no) {
 245                 volume = hammer_get_volume(hmp, vol_no, &error);
 246                 if (volume == NULL && error == ENOENT) {
 247                         /*
 248                          * Skip unused volume numbers
 249                          */
 250                         error = 0;
 251                         continue;
 252                 }
 253                 KKASSERT(volume != NULL && error == 0);
 254                 if (strcmp(volume->vol_name, ioc->device_name) == 0) {
 255                         break;
 256                 }
 257                 hammer_rel_volume(volume, 0);
 258                 volume = NULL;
 259         }
 260
 261         if (volume == NULL) {
 262                 kprintf("Couldn't find volume\n");
 263                 error = EINVAL;
 264                 goto end;
 265         }
 266
 267         if (volume == trans->rootvol) {
 268                 kprintf("Cannot remove root-volume\n");
 269                 hammer_rel_volume(volume, 0);
 270                 error = EINVAL;
 271                 goto end;
 272         }
 273
 274         /*
 275          * Reblock filesystem
 276          */
 277         hmp->volume_to_remove = volume->vol_no;
 278
 279         struct hammer_ioc_reblock reblock;
 280         bzero(&reblock, sizeof(reblock));
 281
 282         reblock.key_beg.localization = HAMMER_MIN_LOCALIZATION;
 283         reblock.key_beg.obj_id = HAMMER_MIN_OBJID;
 284         reblock.key_end.localization = HAMMER_MAX_LOCALIZATION;
 285         reblock.key_end.obj_id = HAMMER_MAX_OBJID;
 286         reblock.head.flags = HAMMER_IOC_DO_FLAGS;
 287         reblock.free_level = 0;
 288
 289         error = hammer_ioc_reblock(trans, ip, &reblock);
 290
 291         if (reblock.head.flags & HAMMER_IOC_HEAD_INTR) {
 292                 error = EINTR;
 293         }
 294
 295         if (error) {
 296                 if (error == EINTR) {
 297                         kprintf("reblock was interrupted\n");
 298                 } else {
 299                         kprintf("reblock failed: %d\n", error);
 300                 }
 301                 hmp->volume_to_remove = -1;
 302                 hammer_rel_volume(volume, 0);
 303                 goto end;
 304         }
 305
 306         /*
 307          * Sync filesystem
 308          */
 309         int count = 0;
 310         while (hammer_flusher_haswork(hmp)) {
 311                 hammer_flusher_sync(hmp);
 312                 ++count;
 313                 if (count >= 5) {
 314                         if (count == 5)
 315                                 kprintf("HAMMER: flushing.");
 316                         else
 317                                 kprintf(".");
 318                         tsleep(&count, 0, "hmrufl", hz);
 319                 }
 320                 if (count == 30) {
 321                         kprintf("giving up");
 322                         break;
 323                 }
 324         }
 325         kprintf("\n");
 326
 327         hammer_sync_lock_sh(trans);
 328         hammer_lock_ex(&hmp->blkmap_lock);
 329
 330         /*
 331          * We use stat later to update rootvol's big-block stats
 332          */
 333         struct bigblock_stat stat;
 334         error = hammer_free_freemap(trans, volume, &stat);
 335         if (error) {
 336                 kprintf("Failed to free volume. Volume not empty!\n");
 337                 hmp->volume_to_remove = -1;
 338                 hammer_rel_volume(volume, 0);
 339                 hammer_unlock(&hmp->blkmap_lock);
 340                 hammer_sync_unlock(trans);
 341                 goto end;
 342         }
 343
 344         hmp->volume_to_remove = -1;
 345
 346         hammer_rel_volume(volume, 0);
 347
 348         /*
 349          * Unload buffers
 350          */
 351         RB_SCAN(hammer_buf_rb_tree, &hmp->rb_bufs_root, NULL,
 352                 hammer_unload_buffer, volume);
 353
 354         error = hammer_unload_volume(volume, NULL);
 355         if (error == -1) {
 356                 kprintf("Failed to unload volume\n");
 357                 hammer_unlock(&hmp->blkmap_lock);
 358                 hammer_sync_unlock(trans);
 359                 goto end;
 360         }
 361
 362         volume = NULL;
 363         --hmp->nvolumes;
 364
 365         /*
 366          * Set each volume's new value of the vol_count field.
 367          */
 368         for (int vol_no = 0; vol_no < HAMMER_MAX_VOLUMES; ++vol_no) {
 369                 volume = hammer_get_volume(hmp, vol_no, &error);
 370                 if (volume == NULL && error == ENOENT) {
 371                         /*
 372                          * Skip unused volume numbers
 373                          */
 374                         error = 0;
 375                         continue;
 376                 }
 377
 378                 KKASSERT(volume != NULL && error == 0);
 379                 hammer_modify_volume_field(trans, volume, vol_count);
 380                 volume->ondisk->vol_count = hmp->nvolumes;
 381                 hammer_modify_volume_done(volume);
 382
 383                 /*
 384                  * Only changes to the header of the root volume
 385                  * are automatically flushed to disk. For all
 386                  * other volumes that we modify we do it here.
 387                  *
 388                  * No interlock is needed, volume buffers are not
 389                  * messed with by bioops.
 390                  */
 391                 if (volume != trans->rootvol && volume->io.modified) {
 392                         hammer_crc_set_volume(volume->ondisk);
 393                         hammer_io_flush(&volume->io, 0);
 394                 }
 395
 396                 hammer_rel_volume(volume, 0);
 397         }
 398
 399         /*
 400          * Update the total number of big-blocks
 401          */
 402         hammer_modify_volume_field(trans, trans->rootvol,
 403                 vol0_stat_bigblocks);
 404         trans->rootvol->ondisk->vol0_stat_bigblocks -= stat.total_bigblocks;
 405         hammer_modify_volume_done(trans->rootvol);
 406
 407         /*
 408          * Update the number of free big-blocks
 409          * (including the copy in hmp)
 410          */
 411         hammer_modify_volume_field(trans, trans->rootvol,
 412                 vol0_stat_freebigblocks);
 413         trans->rootvol->ondisk->vol0_stat_freebigblocks -= stat.total_free_bigblocks;
 414         hmp->copy_stat_freebigblocks =
 415                 trans->rootvol->ondisk->vol0_stat_freebigblocks;
 416         hammer_modify_volume_done(trans->rootvol);
 417         /*
 418          * Big-block count changed so recompute the total number of blocks.
 419          */
 420         mp->mnt_stat.f_blocks = trans->rootvol->ondisk->vol0_stat_bigblocks *
 421             (HAMMER_BIGBLOCK_SIZE / HAMMER_BUFSIZE);
 422         mp->mnt_vstat.f_blocks = trans->rootvol->ondisk->vol0_stat_bigblocks *
 423             (HAMMER_BIGBLOCK_SIZE / HAMMER_BUFSIZE);
 424
 425         hammer_unlock(&hmp->blkmap_lock);
 426         hammer_sync_unlock(trans);
 427
 428         /*
 429          * Erase the volume header of the removed device.
 430          *
 431          * This is to not accidentally mount the volume again.
 432          */
 433         struct vnode *devvp = NULL;
 434         error = hammer_setup_device(&devvp, ioc->device_name, 0);
 435         if (error) {
 436                 kprintf("Failed to open device: %s\n", ioc->device_name);
 437                 goto end;
 438         }
 439         KKASSERT(devvp);
 440         error = hammer_clear_volume_header(devvp);
 441         if (error) {
 442                 kprintf("Failed to clear volume header of device: %s\n",
 443                         ioc->device_name);
 444                 goto end;
 445         }
 446         hammer_close_device(&devvp, 0);
 447
 448         KKASSERT(error == 0);
 449 end:
 450         hammer_unlock(&hmp->volume_lock);
 451         return (error);
 452 }
 453
 454
 455 int
 456 hammer_ioc_volume_list(hammer_transaction_t trans, hammer_inode_t ip,
 457     struct hammer_ioc_volume_list *ioc)
 458 {
 459         struct hammer_mount *hmp = trans->hmp;
 460         hammer_volume_t volume;
 461         int error = 0;
 462         int i, cnt, len;
 463
 464         for (i = 0, cnt = 0; i < HAMMER_MAX_VOLUMES && cnt < ioc->nvols; i++) {
 465                 volume = hammer_get_volume(hmp, i, &error);
 466                 if (volume == NULL && error == ENOENT) {
 467                         error = 0;
 468                         continue;
 469                 }
 470                 KKASSERT(volume != NULL && error == 0);
 471
 472                 len = strlen(volume->vol_name) + 1;
 473                 KKASSERT(len <= MAXPATHLEN);
 474
 475                 error = copyout(volume->vol_name, ioc->vols[cnt].device_name,
 476                                 len);
 477                 if (error) {
 478                         hammer_rel_volume(volume, 0);
 479                         return (error);
 480                 }
 481                 cnt++;
 482                 hammer_rel_volume(volume, 0);
 483         }
 484         ioc->nvols = cnt;
 485
 486         return (error);
 487 }
 488
 489 /*
 490  * Iterate over all usable L1 entries of the volume and
 491  * the corresponding L2 entries.
 492  */
 493 static int
 494 hammer_iterate_l1l2_entries(hammer_transaction_t trans, hammer_volume_t volume,
 495         int (*callback)(hammer_transaction_t, hammer_volume_t, hammer_buffer_t*,
 496                 struct hammer_blockmap_layer1*, struct hammer_blockmap_layer2*,
 497                 hammer_off_t, hammer_off_t, void*),
 498         void *data)
 499 {
 500         struct hammer_mount *hmp = trans->hmp;
 501         hammer_blockmap_t freemap = &hmp->blockmap[HAMMER_ZONE_FREEMAP_INDEX];
 502         hammer_buffer_t buffer = NULL;
 503         int error = 0;
 504
 505         hammer_off_t phys_off;
 506         hammer_off_t block_off;
 507         hammer_off_t layer1_off;
 508         hammer_off_t layer2_off;
 509         hammer_off_t aligned_buf_end_off;
 510         struct hammer_blockmap_layer1 *layer1;
 511         struct hammer_blockmap_layer2 *layer2;
 512
 513         /*
 514          * Calculate the usable size of the volume, which
 515          * must be aligned at a big-block (8 MB) boundary.
 516          */
 517         aligned_buf_end_off = (HAMMER_ENCODE_RAW_BUFFER(volume->ondisk->vol_no,
 518                 (volume->ondisk->vol_buf_end - volume->ondisk->vol_buf_beg)
 519                 & ~HAMMER_BIGBLOCK_MASK64));
 520
 521         /*
 522          * Iterate the volume's address space in chunks of 4 TB, where each
 523          * chunk consists of at least one physically available 8 MB big-block.
 524          *
 525          * For each chunk we need one L1 entry and one L2 big-block.
 526          * We use the first big-block of each chunk as L2 block.
 527          */
 528         for (phys_off = HAMMER_ENCODE_RAW_BUFFER(volume->ondisk->vol_no, 0);
 529              phys_off < aligned_buf_end_off;
 530              phys_off += HAMMER_BLOCKMAP_LAYER2) {
 531                 for (block_off = 0;
 532                      block_off < HAMMER_BLOCKMAP_LAYER2;
 533                      block_off += HAMMER_BIGBLOCK_SIZE) {
 534                         layer2_off = phys_off +
 535                                 HAMMER_BLOCKMAP_LAYER2_OFFSET(block_off);
 536                         layer2 = hammer_bread(hmp, layer2_off, &error, &buffer);
 537                         if (error)
 538                                 goto end;
 539
 540                         error = callback(trans, volume, &buffer, NULL,
 541                                          layer2, phys_off, block_off, data);
 542                         if (error)
 543                                 goto end;
 544                 }
 545
 546                 layer1_off = freemap->phys_offset +
 547                                 HAMMER_BLOCKMAP_LAYER1_OFFSET(phys_off);
 548                 layer1 = hammer_bread(hmp, layer1_off, &error, &buffer);
 549                 if (error)
 550                         goto end;
 551
 552                 error = callback(trans, volume, &buffer, layer1, NULL,
 553                                  phys_off, 0, data);
 554                 if (error)
 555                         goto end;
 556         }
 557
 558 end:
 559         if (buffer) {
 560                 hammer_rel_buffer(buffer, 0);
 561                 buffer = NULL;
 562         }
 563
 564         return error;
 565 }
 566
 567
 568 static int
 569 format_callback(hammer_transaction_t trans, hammer_volume_t volume,
 570         hammer_buffer_t *bufferp,
 571         struct hammer_blockmap_layer1 *layer1,
 572         struct hammer_blockmap_layer2 *layer2,
 573         hammer_off_t phys_off,
 574         hammer_off_t block_off,
 575         void *data)
 576 {
 577         struct bigblock_stat *stat = (struct bigblock_stat*)data;
 578
 579         /*
 580          * Calculate the usable size of the volume, which must be aligned
 581          * at a big-block (8 MB) boundary.
 582          */
 583         hammer_off_t aligned_buf_end_off;
 584         aligned_buf_end_off = (HAMMER_ENCODE_RAW_BUFFER(volume->ondisk->vol_no,
 585                 (volume->ondisk->vol_buf_end - volume->ondisk->vol_buf_beg)
 586                 & ~HAMMER_BIGBLOCK_MASK64));
 587
 588         if (layer1) {
 589                 KKASSERT(layer1->phys_offset == HAMMER_BLOCKMAP_UNAVAIL);
 590
 591                 hammer_modify_buffer(trans, *bufferp, layer1, sizeof(*layer1));
 592                 bzero(layer1, sizeof(*layer1));
 593                 layer1->phys_offset = phys_off;
 594                 layer1->blocks_free = stat->counter;
 595                 layer1->layer1_crc = crc32(layer1, HAMMER_LAYER1_CRCSIZE);
 596                 hammer_modify_buffer_done(*bufferp);
 597
 598                 stat->total_free_bigblocks += stat->counter;
 599                 stat->counter = 0; /* reset */
 600         } else if (layer2) {
 601                 hammer_modify_buffer(trans, *bufferp, layer2, sizeof(*layer2));
 602                 bzero(layer2, sizeof(*layer2));
 603
 604                 if (block_off == 0) {
 605                         /*
 606                          * The first entry represents the L2 big-block itself.
 607                          */
 608                         layer2->zone = HAMMER_ZONE_FREEMAP_INDEX;
 609                         layer2->append_off = HAMMER_BIGBLOCK_SIZE;
 610                         layer2->bytes_free = 0;
 611                         ++stat->total_bigblocks;
 612                 } else if (phys_off + block_off < aligned_buf_end_off) {
 613                         /*
 614                          * Available big-block
 615                          */
 616                         layer2->zone = 0;
 617                         layer2->append_off = 0;
 618                         layer2->bytes_free = HAMMER_BIGBLOCK_SIZE;
 619                         ++stat->total_bigblocks;
 620                         ++stat->counter;
 621                 } else {
 622                         /*
 623                          * Big-block outside of physically available
 624                          * space
 625                          */
 626                         layer2->zone = HAMMER_ZONE_UNAVAIL_INDEX;
 627                         layer2->append_off = HAMMER_BIGBLOCK_SIZE;
 628                         layer2->bytes_free = 0;
 629                 }
 630
 631                 layer2->entry_crc = crc32(layer2, HAMMER_LAYER2_CRCSIZE);
 632                 hammer_modify_buffer_done(*bufferp);
 633         } else {
 634                 KKASSERT(0);
 635         }
 636
 637         return 0;
 638 }
 639
 640 static int
 641 hammer_format_freemap(hammer_transaction_t trans, hammer_volume_t volume,
 642         struct bigblock_stat *stat)
 643 {
 644         stat->total_bigblocks = 0;
 645         stat->total_free_bigblocks = 0;
 646         stat->counter = 0;
 647         return hammer_iterate_l1l2_entries(trans, volume, format_callback, stat);
 648 }
 649
 650 static int
 651 free_callback(hammer_transaction_t trans, hammer_volume_t volume __unused,
 652         hammer_buffer_t *bufferp,
 653         struct hammer_blockmap_layer1 *layer1,
 654         struct hammer_blockmap_layer2 *layer2,
 655         hammer_off_t phys_off,
 656         hammer_off_t block_off __unused,
 657         void *data)
 658 {
 659         struct bigblock_stat *stat = (struct bigblock_stat*)data;
 660
 661         /*
 662          * No modifications to ondisk structures
 663          */
 664         int testonly = (stat == NULL);
 665
 666         if (layer1) {
 667                 if (layer1->phys_offset == HAMMER_BLOCKMAP_UNAVAIL) {
 668                         /*
 669                          * This layer1 entry is already free.
 670                          */
 671                         return 0;
 672                 }
 673
 674                 KKASSERT((int)HAMMER_VOL_DECODE(layer1->phys_offset) ==
 675                         trans->hmp->volume_to_remove);
 676
 677                 if (testonly)
 678                         return 0;
 679
 680                 /*
 681                  * Free the L1 entry
 682                  */
 683                 hammer_modify_buffer(trans, *bufferp, layer1, sizeof(*layer1));
 684                 bzero(layer1, sizeof(*layer1));
 685                 layer1->phys_offset = HAMMER_BLOCKMAP_UNAVAIL;
 686                 layer1->layer1_crc = crc32(layer1, HAMMER_LAYER1_CRCSIZE);
 687                 hammer_modify_buffer_done(*bufferp);
 688
 689                 return 0;
 690         } else if (layer2) {
 691                 if (layer2->zone == HAMMER_ZONE_UNAVAIL_INDEX) {
 692                         return 0;
 693                 }
 694
 695                 if (layer2->zone == HAMMER_ZONE_FREEMAP_INDEX) {
 696                         if (stat) {
 697                                 ++stat->total_bigblocks;
 698                         }
 699                         return 0;
 700                 }
 701
 702                 if (layer2->append_off == 0 &&
 703                     layer2->bytes_free == HAMMER_BIGBLOCK_SIZE) {
 704                         if (stat) {
 705                                 ++stat->total_bigblocks;
 706                                 ++stat->total_free_bigblocks;
 707                         }
 708                         return 0;
 709                 }
 710
 711                 /*
 712                  * We found a layer2 entry that is not empty!
 713                  */
 714                 return EBUSY;
 715         } else {
 716                 KKASSERT(0);
 717         }
 718
 719         return EINVAL;
 720 }
 721
 722 static int
 723 hammer_free_freemap(hammer_transaction_t trans, hammer_volume_t volume,
 724         struct bigblock_stat *stat)
 725 {
 726         int error;
 727
 728         stat->total_bigblocks = 0;
 729         stat->total_free_bigblocks = 0;
 730         stat->counter = 0;
 731
 732         error = hammer_iterate_l1l2_entries(trans, volume, free_callback, NULL);
 733         if (error)
 734                 return error;
 735
 736         error = hammer_iterate_l1l2_entries(trans, volume, free_callback, stat);
 737         return error;
 738 }
 739
 740 /************************************************************************
 741  *                              MISC                                    *
 742  ************************************************************************
 743  */
 744
 745 static int
 746 hammer_setup_device(struct vnode **devvpp, const char *dev_path, int ronly)
 747 {
 748         int error;
 749         struct nlookupdata nd;
 750
 751         /*
 752          * Get the device vnode
 753          */
 754         if (*devvpp == NULL) {
 755                 error = nlookup_init(&nd, dev_path, UIO_SYSSPACE, NLC_FOLLOW);
 756                 if (error == 0)
 757                         error = nlookup(&nd);
 758                 if (error == 0)
 759                         error = cache_vref(&nd.nl_nch, nd.nl_cred, devvpp);
 760                 nlookup_done(&nd);
 761         } else {
 762                 error = 0;
 763         }
 764
 765         if (error == 0) {
 766                 if (vn_isdisk(*devvpp, &error)) {
 767                         error = vfs_mountedon(*devvpp);
 768                 }
 769         }
 770         if (error == 0 && vcount(*devvpp) > 0)
 771                 error = EBUSY;
 772         if (error == 0) {
 773                 vn_lock(*devvpp, LK_EXCLUSIVE | LK_RETRY);
 774                 error = vinvalbuf(*devvpp, V_SAVE, 0, 0);
 775                 if (error == 0) {
 776                         error = VOP_OPEN(*devvpp,
 777                                          (ronly ? FREAD : FREAD|FWRITE),
 778                                          FSCRED, NULL);
 779                 }
 780                 vn_unlock(*devvpp);
 781         }
 782         if (error && *devvpp) {
 783                 vrele(*devvpp);
 784                 *devvpp = NULL;
 785         }
 786         return (error);
 787 }
 788
 789 static void
 790 hammer_close_device(struct vnode **devvpp, int ronly)
 791 {
 792         if (*devvpp) {
 793                 vn_lock(*devvpp, LK_EXCLUSIVE | LK_RETRY);
 794                 vinvalbuf(*devvpp, ronly ? 0 : V_SAVE, 0, 0);
 795                 VOP_CLOSE(*devvpp, (ronly ? FREAD : FREAD|FWRITE), NULL);
 796                 vn_unlock(*devvpp);
 797                 vrele(*devvpp);
 798                 *devvpp = NULL;
 799         }
 800 }
 801
 802 static int
 803 hammer_format_volume_header(struct hammer_mount *hmp, struct vnode *devvp,
 804         const char *vol_name, int vol_no, int vol_count,
 805         int64_t vol_size, int64_t boot_area_size, int64_t mem_area_size)
 806 {
 807         struct buf *bp = NULL;
 808         struct hammer_volume_ondisk *ondisk;
 809         int error;
 810
 811         /*
 812          * Extract the volume number from the volume header and do various
 813          * sanity checks.
 814          */
 815         KKASSERT(HAMMER_BUFSIZE >= sizeof(struct hammer_volume_ondisk));
 816         error = bread(devvp, 0LL, HAMMER_BUFSIZE, &bp);
 817         if (error || bp->b_bcount < sizeof(struct hammer_volume_ondisk))
 818                 goto late_failure;
 819
 820         ondisk = (struct hammer_volume_ondisk*) bp->b_data;
 821
 822         /*
 823          * Note that we do NOT allow to use a device that contains
 824          * a valid HAMMER signature. It has to be cleaned up with dd
 825          * before.
 826          */
 827         if (ondisk->vol_signature == HAMMER_FSBUF_VOLUME) {
 828                 kprintf("hammer_volume_add: Formatting of valid HAMMER volume "
 829                         "%s denied. Erase with dd!\n", vol_name);
 830                 error = EFTYPE;
 831                 goto late_failure;
 832         }
 833
 834         bzero(ondisk, sizeof(struct hammer_volume_ondisk));
 835         ksnprintf(ondisk->vol_name, sizeof(ondisk->vol_name), "%s", vol_name);
 836         ondisk->vol_fstype = hmp->rootvol->ondisk->vol_fstype;
 837         ondisk->vol_signature = HAMMER_FSBUF_VOLUME;
 838         ondisk->vol_fsid = hmp->fsid;
 839         ondisk->vol_rootvol = hmp->rootvol->vol_no;
 840         ondisk->vol_no = vol_no;
 841         ondisk->vol_count = vol_count;
 842         ondisk->vol_version = hmp->version;
 843
 844         /*
 845          * Reserve space for (future) header junk, setup our poor-man's
 846          * big-block allocator.
 847          */
 848         int64_t vol_alloc = HAMMER_BUFSIZE * 16;
 849
 850         ondisk->vol_bot_beg = vol_alloc;
 851         vol_alloc += boot_area_size;
 852         ondisk->vol_mem_beg = vol_alloc;
 853         vol_alloc += mem_area_size;
 854
 855         /*
 856          * The remaining area is the zone 2 buffer allocation area.  These
 857          * buffers
 858          */
 859         ondisk->vol_buf_beg = vol_alloc;
 860         ondisk->vol_buf_end = vol_size & ~(int64_t)HAMMER_BUFMASK;
 861
 862         if (ondisk->vol_buf_end < ondisk->vol_buf_beg) {
 863                 kprintf("volume %d %s is too small to hold the volume header\n",
 864                      ondisk->vol_no, ondisk->vol_name);
 865                 error = EFTYPE;
 866                 goto late_failure;
 867         }
 868
 869         ondisk->vol_nblocks = (ondisk->vol_buf_end - ondisk->vol_buf_beg) /
 870                               HAMMER_BUFSIZE;
 871         ondisk->vol_blocksize = HAMMER_BUFSIZE;
 872
 873         /*
 874          * Write volume header to disk
 875          */
 876         error = bwrite(bp);
 877         bp = NULL;
 878
 879 late_failure:
 880         if (bp)
 881                 brelse(bp);
 882         return (error);
 883 }
 884
 885 /*
 886  * Invalidates the volume header. Used by volume-del.
 887  */
 888 static int
 889 hammer_clear_volume_header(struct vnode *devvp)
 890 {
 891         struct buf *bp = NULL;
 892         struct hammer_volume_ondisk *ondisk;
 893         int error;
 894
 895         KKASSERT(HAMMER_BUFSIZE >= sizeof(struct hammer_volume_ondisk));
 896         error = bread(devvp, 0LL, HAMMER_BUFSIZE, &bp);
 897         if (error || bp->b_bcount < sizeof(struct hammer_volume_ondisk))
 898                 goto late_failure;
 899
 900         ondisk = (struct hammer_volume_ondisk*) bp->b_data;
 901         bzero(ondisk, sizeof(struct hammer_volume_ondisk));
 902
 903         error = bwrite(bp);
 904         bp = NULL;
 905
 906 late_failure:
 907         if (bp)
 908                 brelse(bp);
 909         return (error);
 910 }