lwext4/ext4_balloc.c

   1 /*
   2  * Copyright (c) 2013 Grzegorz Kostka (kostka.grzegorz@gmail.com)
   3  *
   4  *
   5  * HelenOS:
   6  * Copyright (c) 2012 Martin Sucha
   7  * Copyright (c) 2012 Frantisek Princ
   8  * All rights reserved.
   9  *
  10  * Redistribution and use in source and binary forms, with or without
  11  * modification, are permitted provided that the following conditions
  12  * are met:
  13  *
  14  * - Redistributions of source code must retain the above copyright
  15  *   notice, this list of conditions and the following disclaimer.
  16  * - Redistributions in binary form must reproduce the above copyright
  17  *   notice, this list of conditions and the following disclaimer in the
  18  *   documentation and/or other materials provided with the distribution.
  19  * - The name of the author may not be used to endorse or promote products
  20  *   derived from this software without specific prior written permission.
  21  *
  22  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
  23  * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
  24  * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
  25  * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
  26  * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
  27  * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
  28  * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
  29  * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
  30  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
  31  * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  32  */
  33
  34 /** @addtogroup lwext4
  35  * @{
  36  */
  37 /**
  38  * @file  ext4_balloc.c
  39  * @brief Physical block allocator.
  40  */
  41
  42 #include "ext4_config.h"
  43 #include "ext4_balloc.h"
  44 #include "ext4_super.h"
  45 #include "ext4_crc32c.h"
  46 #include "ext4_block_group.h"
  47 #include "ext4_fs.h"
  48 #include "ext4_bitmap.h"
  49 #include "ext4_inode.h"
  50
  51 /**@brief Compute number of block group from block address.
  52  * @param sb superblock pointer.
  53  * @param baddr Absolute address of block.
  54  * @return Block group index
  55  */
  56 uint32_t ext4_balloc_get_bgid_of_block(struct ext4_sblock *s,
  57                                        uint64_t baddr)
  58 {
  59         if (ext4_get32(s, first_data_block) && baddr)
  60                 baddr--;
  61
  62         return baddr / ext4_get32(s, blocks_per_group);
  63 }
  64
  65 /**@brief Compute the starting block address of a block group
  66  * @param sb   superblock pointer.
  67  * @param bgid block group index
  68  * @return Block address
  69  */
  70 uint64_t ext4_balloc_get_block_of_bgid(struct ext4_sblock *s,
  71                                        uint32_t bgid)
  72 {
  73         uint64_t baddr = 0;
  74         if (ext4_get32(s, first_data_block))
  75                 baddr++;
  76
  77         baddr += bgid * ext4_get32(s, blocks_per_group);
  78         return baddr;
  79 }
  80
  81 #if CONFIG_META_CSUM_ENABLE
  82 static uint32_t ext4_balloc_bitmap_csum(struct ext4_sblock *sb,
  83                                         void *bitmap)
  84 {
  85         uint32_t checksum = 0;
  86         if (ext4_sb_feature_ro_com(sb, EXT4_FRO_COM_METADATA_CSUM)) {
  87                 uint32_t blocks_per_group =
  88                         ext4_get32(sb, blocks_per_group);
  89
  90                 /* First calculate crc32 checksum against fs uuid */
  91                 checksum = ext4_crc32c(EXT4_CRC32_INIT, sb->uuid,
  92                                 sizeof(sb->uuid));
  93                 /* Then calculate crc32 checksum against block_group_desc */
  94                 checksum = ext4_crc32c(checksum, bitmap,
  95                                      blocks_per_group / 8);
  96         }
  97         return checksum;
  98 }
  99 #else
 100 #define ext4_balloc_bitmap_csum(...) 0
 101 #endif
 102
 103 void ext4_balloc_set_bitmap_csum(struct ext4_sblock *sb,
 104                                  struct ext4_bgroup *bg,
 105                                  void *bitmap __unused)
 106 {
 107         int desc_size = ext4_sb_get_desc_size(sb);
 108         uint32_t checksum = ext4_balloc_bitmap_csum(sb, bitmap);
 109         uint16_t lo_checksum = to_le16(checksum & 0xFFFF),
 110                  hi_checksum = to_le16(checksum >> 16);
 111
 112         if (!ext4_sb_feature_ro_com(sb, EXT4_FRO_COM_METADATA_CSUM))
 113                 return;
 114
 115         /* See if we need to assign a 32bit checksum */
 116         bg->block_bitmap_csum_lo = lo_checksum;
 117         if (desc_size == EXT4_MAX_BLOCK_GROUP_DESCRIPTOR_SIZE)
 118                 bg->block_bitmap_csum_hi = hi_checksum;
 119
 120 }
 121
 122 #if CONFIG_META_CSUM_ENABLE
 123 static bool
 124 ext4_balloc_verify_bitmap_csum(struct ext4_sblock *sb,
 125                                struct ext4_bgroup *bg,
 126                                void *bitmap __unused)
 127 {
 128         int desc_size = ext4_sb_get_desc_size(sb);
 129         uint32_t checksum = ext4_balloc_bitmap_csum(sb, bitmap);
 130         uint16_t lo_checksum = to_le16(checksum & 0xFFFF),
 131                  hi_checksum = to_le16(checksum >> 16);
 132
 133         if (!ext4_sb_feature_ro_com(sb, EXT4_FRO_COM_METADATA_CSUM))
 134                 return true;
 135
 136         if (bg->block_bitmap_csum_lo != lo_checksum)
 137                 return false;
 138
 139         if (desc_size == EXT4_MAX_BLOCK_GROUP_DESCRIPTOR_SIZE)
 140                 if (bg->block_bitmap_csum_hi != hi_checksum)
 141                         return false;
 142
 143         return true;
 144 }
 145 #else
 146 #define ext4_balloc_verify_bitmap_csum(...) true
 147 #endif
 148
 149 int ext4_balloc_free_block(struct ext4_inode_ref *inode_ref, ext4_fsblk_t baddr)
 150 {
 151         struct ext4_fs *fs = inode_ref->fs;
 152         struct ext4_sblock *sb = &fs->sb;
 153
 154         uint32_t block_group = ext4_balloc_get_bgid_of_block(sb, baddr);
 155         uint32_t index_in_group = ext4_fs_baddr2_index_in_group(sb, baddr);
 156
 157         /* Load block group reference */
 158         struct ext4_block_group_ref bg_ref;
 159         int rc = ext4_fs_get_block_group_ref(fs, block_group, &bg_ref);
 160         if (rc != EOK)
 161                 return rc;
 162
 163         /* Load block with bitmap */
 164         ext4_fsblk_t bitmap_block_addr =
 165             ext4_bg_get_block_bitmap(bg_ref.block_group, sb);
 166
 167         struct ext4_block bitmap_block;
 168
 169         rc = ext4_block_get(fs->bdev, &bitmap_block, bitmap_block_addr);
 170         if (rc != EOK) {
 171                 ext4_fs_put_block_group_ref(&bg_ref);
 172                 return rc;
 173         }
 174
 175         if (!ext4_balloc_verify_bitmap_csum(sb,
 176                                bg_ref.block_group,
 177                                bitmap_block.data)) {
 178                 ext4_dbg(DEBUG_BALLOC,
 179                         DBG_WARN "Bitmap checksum failed."
 180                         "Group: %" PRIu32"\n",
 181                         bg_ref.index);
 182         }
 183
 184         /* Modify bitmap */
 185         ext4_bmap_bit_clr(bitmap_block.data, index_in_group);
 186         ext4_balloc_set_bitmap_csum(sb, bg_ref.block_group,
 187                                     bitmap_block.data);
 188         bitmap_block.dirty = true;
 189
 190         /* Release block with bitmap */
 191         rc = ext4_block_set(fs->bdev, &bitmap_block);
 192         if (rc != EOK) {
 193                 /* Error in saving bitmap */
 194                 ext4_fs_put_block_group_ref(&bg_ref);
 195                 return rc;
 196         }
 197
 198         uint32_t block_size = ext4_sb_get_block_size(sb);
 199
 200         /* Update superblock free blocks count */
 201         uint64_t sb_free_blocks = ext4_sb_get_free_blocks_cnt(sb);
 202         sb_free_blocks++;
 203         ext4_sb_set_free_blocks_cnt(sb, sb_free_blocks);
 204
 205         /* Update inode blocks count */
 206         uint64_t ino_blocks = ext4_inode_get_blocks_count(sb, inode_ref->inode);
 207         ino_blocks -= block_size / EXT4_INODE_BLOCK_SIZE;
 208         ext4_inode_set_blocks_count(sb, inode_ref->inode, ino_blocks);
 209         inode_ref->dirty = true;
 210
 211         /* Update block group free blocks count */
 212         uint32_t free_blocks =
 213             ext4_bg_get_free_blocks_count(bg_ref.block_group, sb);
 214         free_blocks++;
 215         ext4_bg_set_free_blocks_count(bg_ref.block_group, sb, free_blocks);
 216
 217         bg_ref.dirty = true;
 218
 219         /* Release block group reference */
 220         return ext4_fs_put_block_group_ref(&bg_ref);
 221 }
 222
 223 int ext4_balloc_free_blocks(struct ext4_inode_ref *inode_ref, ext4_fsblk_t first,
 224                             uint32_t count)
 225 {
 226         int rc = EOK;
 227         struct ext4_fs *fs = inode_ref->fs;
 228         struct ext4_sblock *sb = &fs->sb;
 229
 230         /* Compute indexes */
 231         uint32_t block_group_first = ext4_balloc_get_bgid_of_block(sb, first);
 232
 233         /* Compute indexes */
 234         uint32_t block_group_last =
 235             ext4_balloc_get_bgid_of_block(sb, first + count - 1);
 236
 237         if (!ext4_sb_feature_incom(sb, EXT4_FINCOM_FLEX_BG)) {
 238                 /*It is not possible without flex_bg that blocks are continuous
 239                  * and and last block belongs to other bg.*/
 240                 ext4_assert(block_group_first == ext4_balloc_get_bgid_of_block(
 241                                                      sb, first + count - 1));
 242         }
 243
 244         /* Load block group reference */
 245         struct ext4_block_group_ref bg_ref;
 246         while (block_group_first <= block_group_last) {
 247
 248                 rc =
 249                     ext4_fs_get_block_group_ref(fs, block_group_first, &bg_ref);
 250                 if (rc != EOK)
 251                         return rc;
 252
 253                 uint32_t index_in_group_first =
 254                     ext4_fs_baddr2_index_in_group(sb, first);
 255
 256                 /* Load block with bitmap */
 257                 ext4_fsblk_t bitmap_block_addr =
 258                     ext4_bg_get_block_bitmap(bg_ref.block_group, sb);
 259
 260                 struct ext4_block bitmap_block;
 261
 262                 rc = ext4_block_get(fs->bdev, &bitmap_block, bitmap_block_addr);
 263                 if (rc != EOK) {
 264                         ext4_fs_put_block_group_ref(&bg_ref);
 265                         return rc;
 266                 }
 267
 268                 if (!ext4_balloc_verify_bitmap_csum(sb,
 269                                        bg_ref.block_group,
 270                                        bitmap_block.data)) {
 271                         ext4_dbg(DEBUG_BALLOC,
 272                                 DBG_WARN "Bitmap checksum failed."
 273                                 "Group: %" PRIu32"\n",
 274                                 bg_ref.index);
 275                 }
 276
 277                 uint32_t free_cnt =
 278                     ext4_sb_get_block_size(sb) * 8 - index_in_group_first;
 279
 280                 /*If last block, free only count blocks*/
 281                 free_cnt = count > free_cnt ? free_cnt : count;
 282
 283                 /* Modify bitmap */
 284                 ext4_bmap_bits_free(bitmap_block.data, index_in_group_first,
 285                                     free_cnt);
 286                 ext4_balloc_set_bitmap_csum(sb, bg_ref.block_group,
 287                                             bitmap_block.data);
 288                 bitmap_block.dirty = true;
 289
 290                 count -= free_cnt;
 291                 first += free_cnt;
 292
 293                 /* Release block with bitmap */
 294                 rc = ext4_block_set(fs->bdev, &bitmap_block);
 295                 if (rc != EOK) {
 296                         ext4_fs_put_block_group_ref(&bg_ref);
 297                         return rc;
 298                 }
 299
 300                 uint32_t block_size = ext4_sb_get_block_size(sb);
 301
 302                 /* Update superblock free blocks count */
 303                 uint64_t sb_free_blocks = ext4_sb_get_free_blocks_cnt(sb);
 304                 sb_free_blocks += free_cnt;
 305                 ext4_sb_set_free_blocks_cnt(sb, sb_free_blocks);
 306
 307                 /* Update inode blocks count */
 308                 uint64_t ino_blocks =
 309                     ext4_inode_get_blocks_count(sb, inode_ref->inode);
 310                 ino_blocks -= free_cnt * (block_size / EXT4_INODE_BLOCK_SIZE);
 311                 ext4_inode_set_blocks_count(sb, inode_ref->inode, ino_blocks);
 312                 inode_ref->dirty = true;
 313
 314                 /* Update block group free blocks count */
 315                 uint32_t free_blocks =
 316                     ext4_bg_get_free_blocks_count(bg_ref.block_group, sb);
 317                 free_blocks += free_cnt;
 318                 ext4_bg_set_free_blocks_count(bg_ref.block_group, sb,
 319                                               free_blocks);
 320                 bg_ref.dirty = true;
 321
 322                 /* Release block group reference */
 323                 rc = ext4_fs_put_block_group_ref(&bg_ref);
 324                 if (rc != EOK)
 325                         break;
 326
 327                 block_group_first++;
 328         }
 329
 330         /*All blocks should be released*/
 331         ext4_assert(count == 0);
 332         return rc;
 333 }
 334
 335 int ext4_balloc_alloc_block(struct ext4_inode_ref *inode_ref,
 336                             ext4_fsblk_t goal,
 337                             ext4_fsblk_t *fblock)
 338 {
 339         ext4_fsblk_t allocated_block = 0;
 340         ext4_fsblk_t bitmap_block_addr;
 341         uint32_t rel_block_idx = 0;
 342         uint64_t free_blocks;
 343         struct ext4_block bitmap_block;
 344         int rc;
 345
 346         struct ext4_sblock *sb = &inode_ref->fs->sb;
 347
 348         /* Load block group number for goal and relative index */
 349         uint32_t block_group = ext4_balloc_get_bgid_of_block(sb, goal);
 350         uint32_t index_in_group = ext4_fs_baddr2_index_in_group(sb, goal);
 351
 352         /* Load block group reference */
 353         struct ext4_block_group_ref bg_ref;
 354         rc = ext4_fs_get_block_group_ref(inode_ref->fs, block_group, &bg_ref);
 355         if (rc != EOK)
 356                 return rc;
 357
 358         free_blocks = ext4_bg_get_free_blocks_count(bg_ref.block_group, sb);
 359         if (free_blocks == 0) {
 360                 /* This group has no free blocks */
 361                 goto goal_failed;
 362         }
 363
 364         /* Compute indexes */
 365         ext4_fsblk_t first_in_group = ext4_balloc_get_block_of_bgid(sb, bg_ref.index);
 366
 367         uint32_t first_in_group_index =
 368             ext4_fs_baddr2_index_in_group(sb, first_in_group);
 369
 370         if (index_in_group < first_in_group_index)
 371                 index_in_group = first_in_group_index;
 372
 373         /* Load block with bitmap */
 374         bitmap_block_addr = ext4_bg_get_block_bitmap(bg_ref.block_group, sb);
 375
 376         rc = ext4_block_get(inode_ref->fs->bdev, &bitmap_block,
 377                             bitmap_block_addr);
 378         if (rc != EOK) {
 379                 ext4_fs_put_block_group_ref(&bg_ref);
 380                 return rc;
 381         }
 382
 383         if (!ext4_balloc_verify_bitmap_csum(sb,
 384                                bg_ref.block_group,
 385                                bitmap_block.data)) {
 386                 ext4_dbg(DEBUG_BALLOC,
 387                         DBG_WARN "Bitmap checksum failed."
 388                         "Group: %" PRIu32"\n",
 389                         bg_ref.index);
 390         }
 391
 392         /* Check if goal is free */
 393         if (ext4_bmap_is_bit_clr(bitmap_block.data, index_in_group)) {
 394                 ext4_bmap_bit_set(bitmap_block.data, index_in_group);
 395                 ext4_balloc_set_bitmap_csum(sb, bg_ref.block_group,
 396                                             bitmap_block.data);
 397                 bitmap_block.dirty = true;
 398                 rc = ext4_block_set(inode_ref->fs->bdev, &bitmap_block);
 399                 if (rc != EOK) {
 400                         ext4_fs_put_block_group_ref(&bg_ref);
 401                         return rc;
 402                 }
 403
 404                 allocated_block = ext4_fs_index_in_group2_baddr(
 405                     sb, index_in_group, block_group);
 406
 407                 goto success;
 408         }
 409
 410         uint32_t blocks_in_group = ext4_blocks_in_group_cnt(sb, block_group);
 411
 412         uint32_t end_idx = (index_in_group + 63) & ~63;
 413         if (end_idx > blocks_in_group)
 414                 end_idx = blocks_in_group;
 415
 416         /* Try to find free block near to goal */
 417         uint32_t tmp_idx;
 418         for (tmp_idx = index_in_group + 1; tmp_idx < end_idx; ++tmp_idx) {
 419                 if (ext4_bmap_is_bit_clr(bitmap_block.data, tmp_idx)) {
 420                         ext4_bmap_bit_set(bitmap_block.data, tmp_idx);
 421
 422                         ext4_balloc_set_bitmap_csum(sb, bg_ref.block_group,
 423                                                     bitmap_block.data);
 424                         bitmap_block.dirty = true;
 425                         rc = ext4_block_set(inode_ref->fs->bdev, &bitmap_block);
 426                         if (rc != EOK)
 427                                 return rc;
 428
 429                         allocated_block = ext4_fs_index_in_group2_baddr(
 430                             sb, tmp_idx, block_group);
 431
 432                         goto success;
 433                 }
 434         }
 435
 436         /* Find free bit in bitmap */
 437         rc = ext4_bmap_bit_find_clr(bitmap_block.data, index_in_group,
 438                                     blocks_in_group, &rel_block_idx);
 439         if (rc == EOK) {
 440                 ext4_bmap_bit_set(bitmap_block.data, rel_block_idx);
 441                 ext4_balloc_set_bitmap_csum(sb, bg_ref.block_group,
 442                                             bitmap_block.data);
 443                 bitmap_block.dirty = true;
 444                 rc = ext4_block_set(inode_ref->fs->bdev, &bitmap_block);
 445                 if (rc != EOK)
 446                         return rc;
 447
 448                 allocated_block = ext4_fs_index_in_group2_baddr(
 449                     sb, rel_block_idx, block_group);
 450
 451                 goto success;
 452         }
 453
 454         /* No free block found yet */
 455         rc = ext4_block_set(inode_ref->fs->bdev, &bitmap_block);
 456         if (rc != EOK) {
 457                 ext4_fs_put_block_group_ref(&bg_ref);
 458                 return rc;
 459         }
 460
 461 goal_failed:
 462
 463         rc = ext4_fs_put_block_group_ref(&bg_ref);
 464         if (rc != EOK)
 465                 return rc;
 466
 467         /* Try other block groups */
 468         uint32_t block_group_count = ext4_block_group_cnt(sb);
 469
 470         uint32_t bgid = (block_group + 1) % block_group_count;
 471         uint32_t count = block_group_count;
 472
 473         while (count > 0) {
 474                 rc = ext4_fs_get_block_group_ref(inode_ref->fs, bgid, &bg_ref);
 475                 if (rc != EOK)
 476                         return rc;
 477
 478                 free_blocks =
 479                     ext4_bg_get_free_blocks_count(bg_ref.block_group, sb);
 480                 if (free_blocks == 0) {
 481                         /* This group has no free blocks */
 482                         goto next_group;
 483                 }
 484
 485                 /* Load block with bitmap */
 486                 bitmap_block_addr =
 487                     ext4_bg_get_block_bitmap(bg_ref.block_group, sb);
 488
 489                 rc = ext4_block_get(inode_ref->fs->bdev, &bitmap_block,
 490                                     bitmap_block_addr);
 491
 492                 if (rc != EOK) {
 493                         ext4_fs_put_block_group_ref(&bg_ref);
 494                         return rc;
 495                 }
 496
 497                 if (!ext4_balloc_verify_bitmap_csum(sb,
 498                                        bg_ref.block_group,
 499                                        bitmap_block.data)) {
 500                         ext4_dbg(DEBUG_BALLOC,
 501                                 DBG_WARN "Bitmap checksum failed."
 502                                 "Group: %" PRIu32"\n",
 503                                 bg_ref.index);
 504                 }
 505
 506                 /* Compute indexes */
 507                 first_in_group = ext4_balloc_get_block_of_bgid(sb, bgid);
 508                 index_in_group =
 509                     ext4_fs_baddr2_index_in_group(sb, first_in_group);
 510                 blocks_in_group = ext4_blocks_in_group_cnt(sb, bgid);
 511
 512                 first_in_group_index =
 513                     ext4_fs_baddr2_index_in_group(sb, first_in_group);
 514
 515                 if (index_in_group < first_in_group_index)
 516                         index_in_group = first_in_group_index;
 517
 518                 rc = ext4_bmap_bit_find_clr(bitmap_block.data, index_in_group,
 519                                             blocks_in_group, &rel_block_idx);
 520
 521                 if (rc == EOK) {
 522
 523                         ext4_bmap_bit_set(bitmap_block.data, rel_block_idx);
 524
 525                         ext4_balloc_set_bitmap_csum(sb, bg_ref.block_group,
 526                                                     bitmap_block.data);
 527                         bitmap_block.dirty = true;
 528                         rc = ext4_block_set(inode_ref->fs->bdev, &bitmap_block);
 529                         if (rc != EOK) {
 530                                 ext4_fs_put_block_group_ref(&bg_ref);
 531                                 return rc;
 532                         }
 533
 534                         allocated_block = ext4_fs_index_in_group2_baddr(
 535                             sb, rel_block_idx, bgid);
 536
 537                         goto success;
 538                 }
 539
 540                 rc = ext4_block_set(inode_ref->fs->bdev, &bitmap_block);
 541                 if (rc != EOK) {
 542                         ext4_fs_put_block_group_ref(&bg_ref);
 543                         return rc;
 544                 }
 545
 546         next_group:
 547                 rc = ext4_fs_put_block_group_ref(&bg_ref);
 548                 if (rc != EOK) {
 549                         return rc;
 550                 }
 551
 552                 /* Goto next group */
 553                 bgid = (bgid + 1) % block_group_count;
 554                 count--;
 555         }
 556
 557         return ENOSPC;
 558
 559 success:
 560     /* Empty command - because of syntax */
 561     ;
 562
 563         uint32_t block_size = ext4_sb_get_block_size(sb);
 564
 565         /* Update superblock free blocks count */
 566         uint64_t sb_free_blocks = ext4_sb_get_free_blocks_cnt(sb);
 567         sb_free_blocks--;
 568         ext4_sb_set_free_blocks_cnt(sb, sb_free_blocks);
 569
 570         /* Update inode blocks (different block size!) count */
 571         uint64_t ino_blocks = ext4_inode_get_blocks_count(sb, inode_ref->inode);
 572         ino_blocks += block_size / EXT4_INODE_BLOCK_SIZE;
 573         ext4_inode_set_blocks_count(sb, inode_ref->inode, ino_blocks);
 574         inode_ref->dirty = true;
 575
 576         /* Update block group free blocks count */
 577         uint64_t bg_free_blocks =
 578             ext4_bg_get_free_blocks_count(bg_ref.block_group, sb);
 579         bg_free_blocks--;
 580         ext4_bg_set_free_blocks_count(bg_ref.block_group, sb, bg_free_blocks);
 581
 582         bg_ref.dirty = true;
 583
 584         rc = ext4_fs_put_block_group_ref(&bg_ref);
 585
 586         *fblock = allocated_block;
 587         return rc;
 588 }
 589
 590 int ext4_balloc_try_alloc_block(struct ext4_inode_ref *inode_ref,
 591                                 ext4_fsblk_t baddr, bool *free)
 592 {
 593         int rc;
 594
 595         struct ext4_fs *fs = inode_ref->fs;
 596         struct ext4_sblock *sb = &fs->sb;
 597
 598         /* Compute indexes */
 599         uint32_t block_group = ext4_balloc_get_bgid_of_block(sb, baddr);
 600         uint32_t index_in_group = ext4_fs_baddr2_index_in_group(sb, baddr);
 601
 602         /* Load block group reference */
 603         struct ext4_block_group_ref bg_ref;
 604         rc = ext4_fs_get_block_group_ref(fs, block_group, &bg_ref);
 605         if (rc != EOK)
 606                 return rc;
 607
 608         /* Load block with bitmap */
 609         ext4_fsblk_t bitmap_block_addr =
 610             ext4_bg_get_block_bitmap(bg_ref.block_group, sb);
 611
 612         struct ext4_block bitmap_block;
 613
 614         rc = ext4_block_get(fs->bdev, &bitmap_block, bitmap_block_addr);
 615         if (rc != EOK) {
 616                 ext4_fs_put_block_group_ref(&bg_ref);
 617                 return rc;
 618         }
 619
 620         if (!ext4_balloc_verify_bitmap_csum(sb,
 621                                bg_ref.block_group,
 622                                bitmap_block.data)) {
 623                 ext4_dbg(DEBUG_BALLOC,
 624                         DBG_WARN "Bitmap checksum failed."
 625                         "Group: %" PRIu32"\n",
 626                         bg_ref.index);
 627         }
 628
 629         /* Check if block is free */
 630         *free = ext4_bmap_is_bit_clr(bitmap_block.data, index_in_group);
 631
 632         /* Allocate block if possible */
 633         if (*free) {
 634                 ext4_bmap_bit_set(bitmap_block.data, index_in_group);
 635                 ext4_balloc_set_bitmap_csum(sb, bg_ref.block_group,
 636                                             bitmap_block.data);
 637                 bitmap_block.dirty = true;
 638         }
 639
 640         /* Release block with bitmap */
 641         rc = ext4_block_set(fs->bdev, &bitmap_block);
 642         if (rc != EOK) {
 643                 /* Error in saving bitmap */
 644                 ext4_fs_put_block_group_ref(&bg_ref);
 645                 return rc;
 646         }
 647
 648         /* If block is not free, return */
 649         if (!(*free))
 650                 goto terminate;
 651
 652         uint32_t block_size = ext4_sb_get_block_size(sb);
 653
 654         /* Update superblock free blocks count */
 655         uint64_t sb_free_blocks = ext4_sb_get_free_blocks_cnt(sb);
 656         sb_free_blocks--;
 657         ext4_sb_set_free_blocks_cnt(sb, sb_free_blocks);
 658
 659         /* Update inode blocks count */
 660         uint64_t ino_blocks = ext4_inode_get_blocks_count(sb, inode_ref->inode);
 661         ino_blocks += block_size / EXT4_INODE_BLOCK_SIZE;
 662         ext4_inode_set_blocks_count(sb, inode_ref->inode, ino_blocks);
 663         inode_ref->dirty = true;
 664
 665         /* Update block group free blocks count */
 666         uint32_t free_blocks =
 667             ext4_bg_get_free_blocks_count(bg_ref.block_group, sb);
 668         free_blocks--;
 669         ext4_bg_set_free_blocks_count(bg_ref.block_group, sb, free_blocks);
 670
 671         bg_ref.dirty = true;
 672
 673 terminate:
 674         return ext4_fs_put_block_group_ref(&bg_ref);
 675 }
 676
 677 /**
 678  * @}
 679  */