lwext4/ext4_balloc.c

   1 /*
   2  * Copyright (c) 2013 Grzegorz Kostka (kostka.grzegorz@gmail.com)
   3  *
   4  * HelenOS:
   5  * Copyright (c) 2012 Martin Sucha
   6  * Copyright (c) 2012 Frantisek Princ
   7  * All rights reserved.
   8  *
   9  * Redistribution and use in source and binary forms, with or without
  10  * modification, are permitted provided that the following conditions
  11  * are met:
  12  *
  13  * - Redistributions of source code must retain the above copyright
  14  *   notice, this list of conditions and the following disclaimer.
  15  * - Redistributions in binary form must reproduce the above copyright
  16  *   notice, this list of conditions and the following disclaimer in the
  17  *   documentation and/or other materials provided with the distribution.
  18  * - The name of the author may not be used to endorse or promote products
  19  *   derived from this software without specific prior written permission.
  20  *
  21  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
  22  * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
  23  * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
  24  * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
  25  * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
  26  * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
  27  * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
  28  * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
  29  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
  30  * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  31  */
  32
  33 /** @addtogroup lwext4
  34  * @{
  35  */
  36 /**
  37  * @file  ext4_balloc.c
  38  * @brief Physical block allocator.
  39  */
  40
  41 #include "ext4_config.h"
  42 #include "ext4_balloc.h"
  43 #include "ext4_super.h"
  44 #include "ext4_crc32c.h"
  45 #include "ext4_block_group.h"
  46 #include "ext4_fs.h"
  47 #include "ext4_bitmap.h"
  48 #include "ext4_inode.h"
  49
  50 /**@brief Compute number of block group from block address.
  51  * @param sb superblock pointer.
  52  * @param baddr Absolute address of block.
  53  * @return Block group index
  54  */
  55 uint32_t ext4_balloc_get_bgid_of_block(struct ext4_sblock *s,
  56                                        uint64_t baddr)
  57 {
  58         if (ext4_get32(s, first_data_block) && baddr)
  59                 baddr--;
  60
  61         return baddr / ext4_get32(s, blocks_per_group);
  62 }
  63
  64 /**@brief Compute the starting block address of a block group
  65  * @param sb   superblock pointer.
  66  * @param bgid block group index
  67  * @return Block address
  68  */
  69 uint64_t ext4_balloc_get_block_of_bgid(struct ext4_sblock *s,
  70                                        uint32_t bgid)
  71 {
  72         uint64_t baddr = 0;
  73         if (ext4_get32(s, first_data_block))
  74                 baddr++;
  75
  76         baddr += bgid * ext4_get32(s, blocks_per_group);
  77         return baddr;
  78 }
  79
  80 #if CONFIG_META_CSUM_ENABLE
  81 static uint32_t ext4_balloc_bitmap_csum(struct ext4_sblock *sb,
  82                                         void *bitmap)
  83 {
  84         uint32_t checksum = 0;
  85         if (ext4_sb_feature_ro_com(sb, EXT4_FRO_COM_METADATA_CSUM)) {
  86                 uint32_t blocks_per_group = ext4_get32(sb, blocks_per_group);
  87
  88                 /* First calculate crc32 checksum against fs uuid */
  89                 checksum = ext4_crc32c(EXT4_CRC32_INIT, sb->uuid,
  90                                 sizeof(sb->uuid));
  91                 /* Then calculate crc32 checksum against block_group_desc */
  92                 checksum = ext4_crc32c(checksum, bitmap, blocks_per_group / 8);
  93         }
  94         return checksum;
  95 }
  96 #else
  97 #define ext4_balloc_bitmap_csum(...) 0
  98 #endif
  99
 100 void ext4_balloc_set_bitmap_csum(struct ext4_sblock *sb,
 101                                  struct ext4_bgroup *bg,
 102                                  void *bitmap __unused)
 103 {
 104         int desc_size = ext4_sb_get_desc_size(sb);
 105         uint32_t checksum = ext4_balloc_bitmap_csum(sb, bitmap);
 106         uint16_t lo_checksum = to_le16(checksum & 0xFFFF),
 107                  hi_checksum = to_le16(checksum >> 16);
 108
 109         if (!ext4_sb_feature_ro_com(sb, EXT4_FRO_COM_METADATA_CSUM))
 110                 return;
 111
 112         /* See if we need to assign a 32bit checksum */
 113         bg->block_bitmap_csum_lo = lo_checksum;
 114         if (desc_size == EXT4_MAX_BLOCK_GROUP_DESCRIPTOR_SIZE)
 115                 bg->block_bitmap_csum_hi = hi_checksum;
 116
 117 }
 118
 119 #if CONFIG_META_CSUM_ENABLE
 120 static bool
 121 ext4_balloc_verify_bitmap_csum(struct ext4_sblock *sb,
 122                                struct ext4_bgroup *bg,
 123                                void *bitmap __unused)
 124 {
 125         int desc_size = ext4_sb_get_desc_size(sb);
 126         uint32_t checksum = ext4_balloc_bitmap_csum(sb, bitmap);
 127         uint16_t lo_checksum = to_le16(checksum & 0xFFFF),
 128                  hi_checksum = to_le16(checksum >> 16);
 129
 130         if (!ext4_sb_feature_ro_com(sb, EXT4_FRO_COM_METADATA_CSUM))
 131                 return true;
 132
 133         if (bg->block_bitmap_csum_lo != lo_checksum)
 134                 return false;
 135
 136         if (desc_size == EXT4_MAX_BLOCK_GROUP_DESCRIPTOR_SIZE)
 137                 if (bg->block_bitmap_csum_hi != hi_checksum)
 138                         return false;
 139
 140         return true;
 141 }
 142 #else
 143 #define ext4_balloc_verify_bitmap_csum(...) true
 144 #endif
 145
 146 int ext4_balloc_free_block(struct ext4_inode_ref *inode_ref, ext4_fsblk_t baddr)
 147 {
 148         struct ext4_fs *fs = inode_ref->fs;
 149         struct ext4_sblock *sb = &fs->sb;
 150
 151         uint32_t bg_id = ext4_balloc_get_bgid_of_block(sb, baddr);
 152         uint32_t index_in_group = ext4_fs_addr_to_idx_bg(sb, baddr);
 153
 154         /* Load block group reference */
 155         struct ext4_block_group_ref bg_ref;
 156         int rc = ext4_fs_get_block_group_ref(fs, bg_id, &bg_ref);
 157         if (rc != EOK)
 158                 return rc;
 159
 160         struct ext4_bgroup *bg = bg_ref.block_group;
 161
 162         /* Load block with bitmap */
 163         ext4_fsblk_t bitmap_block_addr =
 164             ext4_bg_get_block_bitmap(bg, sb);
 165
 166         struct ext4_block bitmap_block;
 167
 168         rc = ext4_block_get(fs->bdev, &bitmap_block, bitmap_block_addr);
 169         if (rc != EOK) {
 170                 ext4_fs_put_block_group_ref(&bg_ref);
 171                 return rc;
 172         }
 173
 174         if (!ext4_balloc_verify_bitmap_csum(sb, bg, bitmap_block.data)) {
 175                 ext4_dbg(DEBUG_BALLOC,
 176                         DBG_WARN "Bitmap checksum failed."
 177                         "Group: %" PRIu32"\n",
 178                         bg_ref.index);
 179         }
 180
 181         /* Modify bitmap */
 182         ext4_bmap_bit_clr(bitmap_block.data, index_in_group);
 183         ext4_balloc_set_bitmap_csum(sb, bg, bitmap_block.data);
 184         ext4_bcache_set_dirty(bitmap_block.buf);
 185
 186         /* Release block with bitmap */
 187         rc = ext4_block_set(fs->bdev, &bitmap_block);
 188         if (rc != EOK) {
 189                 /* Error in saving bitmap */
 190                 ext4_fs_put_block_group_ref(&bg_ref);
 191                 return rc;
 192         }
 193
 194         uint32_t block_size = ext4_sb_get_block_size(sb);
 195
 196         /* Update superblock free blocks count */
 197         uint64_t sb_free_blocks = ext4_sb_get_free_blocks_cnt(sb);
 198         sb_free_blocks++;
 199         ext4_sb_set_free_blocks_cnt(sb, sb_free_blocks);
 200
 201         /* Update inode blocks count */
 202         uint64_t ino_blocks = ext4_inode_get_blocks_count(sb, inode_ref->inode);
 203         ino_blocks -= block_size / EXT4_INODE_BLOCK_SIZE;
 204         ext4_inode_set_blocks_count(sb, inode_ref->inode, ino_blocks);
 205         inode_ref->dirty = true;
 206
 207         /* Update block group free blocks count */
 208         uint32_t free_blocks = ext4_bg_get_free_blocks_count(bg, sb);
 209         free_blocks++;
 210         ext4_bg_set_free_blocks_count(bg, sb, free_blocks);
 211
 212         bg_ref.dirty = true;
 213
 214         /* Release block group reference */
 215         return ext4_fs_put_block_group_ref(&bg_ref);
 216 }
 217
 218 int ext4_balloc_free_blocks(struct ext4_inode_ref *inode_ref,
 219                             ext4_fsblk_t first, uint32_t count)
 220 {
 221         int rc = EOK;
 222         struct ext4_fs *fs = inode_ref->fs;
 223         struct ext4_sblock *sb = &fs->sb;
 224
 225         /* Compute indexes */
 226         uint32_t bg_first = ext4_balloc_get_bgid_of_block(sb, first);
 227
 228         /* Compute indexes */
 229         uint32_t bg_last = ext4_balloc_get_bgid_of_block(sb, first + count - 1);
 230
 231         if (!ext4_sb_feature_incom(sb, EXT4_FINCOM_FLEX_BG)) {
 232                 /*It is not possible without flex_bg that blocks are continuous
 233                  * and and last block belongs to other bg.*/
 234                 if (bg_last != bg_first) {
 235                         ext4_dbg(DEBUG_BALLOC, DBG_WARN "FLEX_BG: disabled & "
 236                                 "bg_last: %"PRIu32" bg_first: %"PRIu32"\n",
 237                                 bg_last, bg_first);
 238                 }
 239         }
 240
 241         /* Load block group reference */
 242         struct ext4_block_group_ref bg_ref;
 243         while (bg_first <= bg_last) {
 244
 245                 rc = ext4_fs_get_block_group_ref(fs, bg_first, &bg_ref);
 246                 if (rc != EOK)
 247                         return rc;
 248
 249                 struct ext4_bgroup *bg = bg_ref.block_group;
 250
 251                 uint32_t idx_in_bg_first;
 252                 idx_in_bg_first = ext4_fs_addr_to_idx_bg(sb, first);
 253
 254                 /* Load block with bitmap */
 255                 ext4_fsblk_t bitmap_blk = ext4_bg_get_block_bitmap(bg, sb);
 256
 257                 struct ext4_block blk;
 258                 rc = ext4_block_get(fs->bdev, &blk, bitmap_blk);
 259                 if (rc != EOK) {
 260                         ext4_fs_put_block_group_ref(&bg_ref);
 261                         return rc;
 262                 }
 263
 264                 if (!ext4_balloc_verify_bitmap_csum(sb, bg, blk.data)) {
 265                         ext4_dbg(DEBUG_BALLOC,
 266                                 DBG_WARN "Bitmap checksum failed."
 267                                 "Group: %" PRIu32"\n",
 268                                 bg_ref.index);
 269                 }
 270                 uint32_t free_cnt;
 271                 free_cnt = ext4_sb_get_block_size(sb) * 8 - idx_in_bg_first;
 272
 273                 /*If last block, free only count blocks*/
 274                 free_cnt = count > free_cnt ? free_cnt : count;
 275
 276                 /* Modify bitmap */
 277                 ext4_bmap_bits_free(blk.data, idx_in_bg_first, free_cnt);
 278                 ext4_balloc_set_bitmap_csum(sb, bg, blk.data);
 279                 ext4_bcache_set_dirty(blk.buf);
 280
 281                 count -= free_cnt;
 282                 first += free_cnt;
 283
 284                 /* Release block with bitmap */
 285                 rc = ext4_block_set(fs->bdev, &blk);
 286                 if (rc != EOK) {
 287                         ext4_fs_put_block_group_ref(&bg_ref);
 288                         return rc;
 289                 }
 290
 291                 uint32_t block_size = ext4_sb_get_block_size(sb);
 292
 293                 /* Update superblock free blocks count */
 294                 uint64_t sb_free_blocks = ext4_sb_get_free_blocks_cnt(sb);
 295                 sb_free_blocks += free_cnt;
 296                 ext4_sb_set_free_blocks_cnt(sb, sb_free_blocks);
 297
 298                 /* Update inode blocks count */
 299                 uint64_t ino_blocks;
 300                 ino_blocks = ext4_inode_get_blocks_count(sb, inode_ref->inode);
 301                 ino_blocks -= free_cnt * (block_size / EXT4_INODE_BLOCK_SIZE);
 302                 ext4_inode_set_blocks_count(sb, inode_ref->inode, ino_blocks);
 303                 inode_ref->dirty = true;
 304
 305                 /* Update block group free blocks count */
 306                 uint32_t free_blocks;
 307                 free_blocks = ext4_bg_get_free_blocks_count(bg, sb);
 308                 free_blocks += free_cnt;
 309                 ext4_bg_set_free_blocks_count(bg, sb, free_blocks);
 310                 bg_ref.dirty = true;
 311
 312                 /* Release block group reference */
 313                 rc = ext4_fs_put_block_group_ref(&bg_ref);
 314                 if (rc != EOK)
 315                         break;
 316
 317                 bg_first++;
 318         }
 319
 320         /*All blocks should be released*/
 321         ext4_assert(count == 0);
 322         return rc;
 323 }
 324
 325 int ext4_balloc_alloc_block(struct ext4_inode_ref *inode_ref,
 326                             ext4_fsblk_t goal,
 327                             ext4_fsblk_t *fblock)
 328 {
 329         ext4_fsblk_t alloc = 0;
 330         ext4_fsblk_t bmp_blk_adr;
 331         uint32_t rel_blk_idx = 0;
 332         uint64_t free_blocks;
 333         int r;
 334         struct ext4_sblock *sb = &inode_ref->fs->sb;
 335
 336         /* Load block group number for goal and relative index */
 337         uint32_t bg_id = ext4_balloc_get_bgid_of_block(sb, goal);
 338         uint32_t idx_in_bg = ext4_fs_addr_to_idx_bg(sb, goal);
 339
 340         struct ext4_block b;
 341         struct ext4_block_group_ref bg_ref;
 342
 343         /* Load block group reference */
 344         r = ext4_fs_get_block_group_ref(inode_ref->fs, bg_id, &bg_ref);
 345         if (r != EOK)
 346                 return r;
 347
 348         struct ext4_bgroup *bg = bg_ref.block_group;
 349
 350         free_blocks = ext4_bg_get_free_blocks_count(bg_ref.block_group, sb);
 351         if (free_blocks == 0) {
 352                 /* This group has no free blocks */
 353                 goto goal_failed;
 354         }
 355
 356         /* Compute indexes */
 357         ext4_fsblk_t first_in_bg;
 358         first_in_bg = ext4_balloc_get_block_of_bgid(sb, bg_ref.index);
 359
 360         uint32_t first_in_bg_index;
 361         first_in_bg_index = ext4_fs_addr_to_idx_bg(sb, first_in_bg);
 362
 363         if (idx_in_bg < first_in_bg_index)
 364                 idx_in_bg = first_in_bg_index;
 365
 366         /* Load block with bitmap */
 367         bmp_blk_adr = ext4_bg_get_block_bitmap(bg_ref.block_group, sb);
 368
 369         r = ext4_block_get(inode_ref->fs->bdev, &b, bmp_blk_adr);
 370         if (r != EOK) {
 371                 ext4_fs_put_block_group_ref(&bg_ref);
 372                 return r;
 373         }
 374
 375         if (!ext4_balloc_verify_bitmap_csum(sb, bg, b.data)) {
 376                 ext4_dbg(DEBUG_BALLOC,
 377                         DBG_WARN "Bitmap checksum failed."
 378                         "Group: %" PRIu32"\n",
 379                         bg_ref.index);
 380         }
 381
 382         /* Check if goal is free */
 383         if (ext4_bmap_is_bit_clr(b.data, idx_in_bg)) {
 384                 ext4_bmap_bit_set(b.data, idx_in_bg);
 385                 ext4_balloc_set_bitmap_csum(sb, bg_ref.block_group,
 386                                             b.data);
 387                 ext4_bcache_set_dirty(b.buf);
 388                 r = ext4_block_set(inode_ref->fs->bdev, &b);
 389                 if (r != EOK) {
 390                         ext4_fs_put_block_group_ref(&bg_ref);
 391                         return r;
 392                 }
 393
 394                 alloc = ext4_fs_bg_idx_to_addr(sb, idx_in_bg, bg_id);
 395                 goto success;
 396         }
 397
 398         uint32_t blk_in_bg = ext4_blocks_in_group_cnt(sb, bg_id);
 399
 400         uint32_t end_idx = (idx_in_bg + 63) & ~63;
 401         if (end_idx > blk_in_bg)
 402                 end_idx = blk_in_bg;
 403
 404         /* Try to find free block near to goal */
 405         uint32_t tmp_idx;
 406         for (tmp_idx = idx_in_bg + 1; tmp_idx < end_idx; ++tmp_idx) {
 407                 if (ext4_bmap_is_bit_clr(b.data, tmp_idx)) {
 408                         ext4_bmap_bit_set(b.data, tmp_idx);
 409
 410                         ext4_balloc_set_bitmap_csum(sb, bg, b.data);
 411                         ext4_bcache_set_dirty(b.buf);
 412                         r = ext4_block_set(inode_ref->fs->bdev, &b);
 413                         if (r != EOK)
 414                                 return r;
 415
 416                         alloc = ext4_fs_bg_idx_to_addr(sb, tmp_idx, bg_id);
 417                         goto success;
 418                 }
 419         }
 420
 421         /* Find free bit in bitmap */
 422         r = ext4_bmap_bit_find_clr(b.data, idx_in_bg, blk_in_bg, &rel_blk_idx);
 423         if (r == EOK) {
 424                 ext4_bmap_bit_set(b.data, rel_blk_idx);
 425                 ext4_balloc_set_bitmap_csum(sb, bg_ref.block_group, b.data);
 426                 ext4_bcache_set_dirty(b.buf);
 427                 r = ext4_block_set(inode_ref->fs->bdev, &b);
 428                 if (r != EOK)
 429                         return r;
 430
 431                 alloc = ext4_fs_bg_idx_to_addr(sb, rel_blk_idx, bg_id);
 432                 goto success;
 433         }
 434
 435         /* No free block found yet */
 436         r = ext4_block_set(inode_ref->fs->bdev, &b);
 437         if (r != EOK) {
 438                 ext4_fs_put_block_group_ref(&bg_ref);
 439                 return r;
 440         }
 441
 442 goal_failed:
 443
 444         r = ext4_fs_put_block_group_ref(&bg_ref);
 445         if (r != EOK)
 446                 return r;
 447
 448         /* Try other block groups */
 449         uint32_t block_group_count = ext4_block_group_cnt(sb);
 450         uint32_t bgid = (bg_id + 1) % block_group_count;
 451         uint32_t count = block_group_count;
 452
 453         while (count > 0) {
 454                 r = ext4_fs_get_block_group_ref(inode_ref->fs, bgid, &bg_ref);
 455                 if (r != EOK)
 456                         return r;
 457
 458                 struct ext4_bgroup *bg = bg_ref.block_group;
 459                 free_blocks = ext4_bg_get_free_blocks_count(bg, sb);
 460                 if (free_blocks == 0) {
 461                         /* This group has no free blocks */
 462                         goto next_group;
 463                 }
 464
 465                 /* Load block with bitmap */
 466                 bmp_blk_adr = ext4_bg_get_block_bitmap(bg, sb);
 467                 r = ext4_block_get(inode_ref->fs->bdev, &b, bmp_blk_adr);
 468                 if (r != EOK) {
 469                         ext4_fs_put_block_group_ref(&bg_ref);
 470                         return r;
 471                 }
 472
 473                 if (!ext4_balloc_verify_bitmap_csum(sb, bg, b.data)) {
 474                         ext4_dbg(DEBUG_BALLOC,
 475                                 DBG_WARN "Bitmap checksum failed."
 476                                 "Group: %" PRIu32"\n",
 477                                 bg_ref.index);
 478                 }
 479
 480                 /* Compute indexes */
 481                 first_in_bg = ext4_balloc_get_block_of_bgid(sb, bgid);
 482                 idx_in_bg = ext4_fs_addr_to_idx_bg(sb, first_in_bg);
 483                 blk_in_bg = ext4_blocks_in_group_cnt(sb, bgid);
 484                 first_in_bg_index = ext4_fs_addr_to_idx_bg(sb, first_in_bg);
 485
 486                 if (idx_in_bg < first_in_bg_index)
 487                         idx_in_bg = first_in_bg_index;
 488
 489                 r = ext4_bmap_bit_find_clr(b.data, idx_in_bg, blk_in_bg,
 490                                 &rel_blk_idx);
 491                 if (r == EOK) {
 492                         ext4_bmap_bit_set(b.data, rel_blk_idx);
 493                         ext4_balloc_set_bitmap_csum(sb, bg, b.data);
 494                         ext4_bcache_set_dirty(b.buf);
 495                         r = ext4_block_set(inode_ref->fs->bdev, &b);
 496                         if (r != EOK) {
 497                                 ext4_fs_put_block_group_ref(&bg_ref);
 498                                 return r;
 499                         }
 500
 501                         alloc = ext4_fs_bg_idx_to_addr(sb, rel_blk_idx, bgid);
 502                         goto success;
 503                 }
 504
 505                 r = ext4_block_set(inode_ref->fs->bdev, &b);
 506                 if (r != EOK) {
 507                         ext4_fs_put_block_group_ref(&bg_ref);
 508                         return r;
 509                 }
 510
 511         next_group:
 512                 r = ext4_fs_put_block_group_ref(&bg_ref);
 513                 if (r != EOK) {
 514                         return r;
 515                 }
 516
 517                 /* Goto next group */
 518                 bgid = (bgid + 1) % block_group_count;
 519                 count--;
 520         }
 521
 522         return ENOSPC;
 523
 524 success:
 525     /* Empty command - because of syntax */
 526     ;
 527
 528         uint32_t block_size = ext4_sb_get_block_size(sb);
 529
 530         /* Update superblock free blocks count */
 531         uint64_t sb_free_blocks = ext4_sb_get_free_blocks_cnt(sb);
 532         sb_free_blocks--;
 533         ext4_sb_set_free_blocks_cnt(sb, sb_free_blocks);
 534
 535         /* Update inode blocks (different block size!) count */
 536         uint64_t ino_blocks = ext4_inode_get_blocks_count(sb, inode_ref->inode);
 537         ino_blocks += block_size / EXT4_INODE_BLOCK_SIZE;
 538         ext4_inode_set_blocks_count(sb, inode_ref->inode, ino_blocks);
 539         inode_ref->dirty = true;
 540
 541         /* Update block group free blocks count */
 542
 543         uint32_t fb_cnt = ext4_bg_get_free_blocks_count(bg_ref.block_group, sb);
 544         fb_cnt--;
 545         ext4_bg_set_free_blocks_count(bg_ref.block_group, sb, fb_cnt);
 546
 547         bg_ref.dirty = true;
 548         r = ext4_fs_put_block_group_ref(&bg_ref);
 549
 550         *fblock = alloc;
 551         return r;
 552 }
 553
 554 int ext4_balloc_try_alloc_block(struct ext4_inode_ref *inode_ref,
 555                                 ext4_fsblk_t baddr, bool *free)
 556 {
 557         int rc;
 558
 559         struct ext4_fs *fs = inode_ref->fs;
 560         struct ext4_sblock *sb = &fs->sb;
 561
 562         /* Compute indexes */
 563         uint32_t block_group = ext4_balloc_get_bgid_of_block(sb, baddr);
 564         uint32_t index_in_group = ext4_fs_addr_to_idx_bg(sb, baddr);
 565
 566         /* Load block group reference */
 567         struct ext4_block_group_ref bg_ref;
 568         rc = ext4_fs_get_block_group_ref(fs, block_group, &bg_ref);
 569         if (rc != EOK)
 570                 return rc;
 571
 572         /* Load block with bitmap */
 573         ext4_fsblk_t bmp_blk_addr;
 574         bmp_blk_addr = ext4_bg_get_block_bitmap(bg_ref.block_group, sb);
 575
 576         struct ext4_block b;
 577         rc = ext4_block_get(fs->bdev, &b, bmp_blk_addr);
 578         if (rc != EOK) {
 579                 ext4_fs_put_block_group_ref(&bg_ref);
 580                 return rc;
 581         }
 582
 583         if (!ext4_balloc_verify_bitmap_csum(sb, bg_ref.block_group, b.data)) {
 584                 ext4_dbg(DEBUG_BALLOC,
 585                         DBG_WARN "Bitmap checksum failed."
 586                         "Group: %" PRIu32"\n",
 587                         bg_ref.index);
 588         }
 589
 590         /* Check if block is free */
 591         *free = ext4_bmap_is_bit_clr(b.data, index_in_group);
 592
 593         /* Allocate block if possible */
 594         if (*free) {
 595                 ext4_bmap_bit_set(b.data, index_in_group);
 596                 ext4_balloc_set_bitmap_csum(sb, bg_ref.block_group, b.data);
 597                 ext4_bcache_set_dirty(b.buf);
 598         }
 599
 600         /* Release block with bitmap */
 601         rc = ext4_block_set(fs->bdev, &b);
 602         if (rc != EOK) {
 603                 /* Error in saving bitmap */
 604                 ext4_fs_put_block_group_ref(&bg_ref);
 605                 return rc;
 606         }
 607
 608         /* If block is not free, return */
 609         if (!(*free))
 610                 goto terminate;
 611
 612         uint32_t block_size = ext4_sb_get_block_size(sb);
 613
 614         /* Update superblock free blocks count */
 615         uint64_t sb_free_blocks = ext4_sb_get_free_blocks_cnt(sb);
 616         sb_free_blocks--;
 617         ext4_sb_set_free_blocks_cnt(sb, sb_free_blocks);
 618
 619         /* Update inode blocks count */
 620         uint64_t ino_blocks = ext4_inode_get_blocks_count(sb, inode_ref->inode);
 621         ino_blocks += block_size / EXT4_INODE_BLOCK_SIZE;
 622         ext4_inode_set_blocks_count(sb, inode_ref->inode, ino_blocks);
 623         inode_ref->dirty = true;
 624
 625         /* Update block group free blocks count */
 626         uint32_t fb_cnt = ext4_bg_get_free_blocks_count(bg_ref.block_group, sb);
 627         fb_cnt--;
 628         ext4_bg_set_free_blocks_count(bg_ref.block_group, sb, fb_cnt);
 629
 630         bg_ref.dirty = true;
 631
 632 terminate:
 633         return ext4_fs_put_block_group_ref(&bg_ref);
 634 }
 635
 636 /**
 637  * @}
 638  */