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         /* 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
 126         if (!ext4_sb_feature_ro_com(sb, EXT4_FRO_COM_METADATA_CSUM))
 127                 return true;
 128
 129         int desc_size = ext4_sb_get_desc_size(sb);
 130         uint32_t checksum = ext4_balloc_bitmap_csum(sb, bitmap);
 131         uint16_t lo_checksum = to_le16(checksum & 0xFFFF),
 132                  hi_checksum = to_le16(checksum >> 16);
 133
 134         if (bg->block_bitmap_csum_lo != lo_checksum)
 135                 return false;
 136
 137         if (desc_size == EXT4_MAX_BLOCK_GROUP_DESCRIPTOR_SIZE)
 138                 if (bg->block_bitmap_csum_hi != hi_checksum)
 139                         return false;
 140
 141         return true;
 142 }
 143 #else
 144 #define ext4_balloc_verify_bitmap_csum(...) true
 145 #endif
 146
 147 int ext4_balloc_free_block(struct ext4_inode_ref *inode_ref, ext4_fsblk_t baddr)
 148 {
 149         struct ext4_fs *fs = inode_ref->fs;
 150         struct ext4_sblock *sb = &fs->sb;
 151
 152         uint32_t block_group = ext4_balloc_get_bgid_of_block(sb, baddr);
 153         uint32_t index_in_group = ext4_fs_baddr2_index_in_group(sb, baddr);
 154
 155         /* Load block group reference */
 156         struct ext4_block_group_ref bg_ref;
 157         int rc = ext4_fs_get_block_group_ref(fs, block_group, &bg_ref);
 158         if (rc != EOK)
 159                 return rc;
 160
 161         /* Load block with bitmap */
 162         ext4_fsblk_t bitmap_block_addr =
 163             ext4_bg_get_block_bitmap(bg_ref.block_group, sb);
 164
 165         struct ext4_block bitmap_block;
 166
 167         rc = ext4_block_get(fs->bdev, &bitmap_block, bitmap_block_addr);
 168         if (rc != EOK) {
 169                 ext4_fs_put_block_group_ref(&bg_ref);
 170                 return rc;
 171         }
 172
 173         if (!ext4_balloc_verify_bitmap_csum(sb,
 174                                bg_ref.block_group,
 175                                bitmap_block.data)) {
 176                 ext4_dbg(DEBUG_BALLOC,
 177                         DBG_WARN "Bitmap checksum failed."
 178                         "Group: %" PRIu32"\n",
 179                         bg_ref.index);
 180         }
 181
 182         /* Modify bitmap */
 183         ext4_bmap_bit_clr(bitmap_block.data, index_in_group);
 184         ext4_balloc_set_bitmap_csum(sb, bg_ref.block_group,
 185                                     bitmap_block.data);
 186         bitmap_block.dirty = true;
 187
 188         /* Release block with bitmap */
 189         rc = ext4_block_set(fs->bdev, &bitmap_block);
 190         if (rc != EOK) {
 191                 /* Error in saving bitmap */
 192                 ext4_fs_put_block_group_ref(&bg_ref);
 193                 return rc;
 194         }
 195
 196         uint32_t block_size = ext4_sb_get_block_size(sb);
 197
 198         /* Update superblock free blocks count */
 199         uint64_t sb_free_blocks = ext4_sb_get_free_blocks_cnt(sb);
 200         sb_free_blocks++;
 201         ext4_sb_set_free_blocks_cnt(sb, sb_free_blocks);
 202
 203         /* Update inode blocks count */
 204         uint64_t ino_blocks = ext4_inode_get_blocks_count(sb, inode_ref->inode);
 205         ino_blocks -= block_size / EXT4_INODE_BLOCK_SIZE;
 206         ext4_inode_set_blocks_count(sb, inode_ref->inode, ino_blocks);
 207         inode_ref->dirty = true;
 208
 209         /* Update block group free blocks count */
 210         uint32_t free_blocks =
 211             ext4_bg_get_free_blocks_count(bg_ref.block_group, sb);
 212         free_blocks++;
 213         ext4_bg_set_free_blocks_count(bg_ref.block_group, sb, free_blocks);
 214
 215         bg_ref.dirty = true;
 216
 217         /* Release block group reference */
 218         return ext4_fs_put_block_group_ref(&bg_ref);
 219 }
 220
 221 int ext4_balloc_free_blocks(struct ext4_inode_ref *inode_ref, ext4_fsblk_t first,
 222                             uint32_t count)
 223 {
 224         int rc = EOK;
 225         struct ext4_fs *fs = inode_ref->fs;
 226         struct ext4_sblock *sb = &fs->sb;
 227
 228         /* Compute indexes */
 229         uint32_t block_group_first = ext4_balloc_get_bgid_of_block(sb, first);
 230
 231         /* Compute indexes */
 232         uint32_t block_group_last =
 233             ext4_balloc_get_bgid_of_block(sb, first + count - 1);
 234
 235         if (!ext4_sb_feature_incom(sb, EXT4_FINCOM_FLEX_BG)) {
 236                 /*It is not possible without flex_bg that blocks are continuous
 237                  * and and last block belongs to other bg.*/
 238                 ext4_assert(block_group_first == ext4_balloc_get_bgid_of_block(
 239                                                      sb, first + count - 1));
 240         }
 241
 242         /* Load block group reference */
 243         struct ext4_block_group_ref bg_ref;
 244         while (block_group_first <= block_group_last) {
 245
 246                 rc =
 247                     ext4_fs_get_block_group_ref(fs, block_group_first, &bg_ref);
 248                 if (rc != EOK)
 249                         return rc;
 250
 251                 uint32_t index_in_group_first =
 252                     ext4_fs_baddr2_index_in_group(sb, first);
 253
 254                 /* Load block with bitmap */
 255                 ext4_fsblk_t bitmap_block_addr =
 256                     ext4_bg_get_block_bitmap(bg_ref.block_group, sb);
 257
 258                 struct ext4_block bitmap_block;
 259
 260                 rc = ext4_block_get(fs->bdev, &bitmap_block, bitmap_block_addr);
 261                 if (rc != EOK) {
 262                         ext4_fs_put_block_group_ref(&bg_ref);
 263                         return rc;
 264                 }
 265
 266                 if (!ext4_balloc_verify_bitmap_csum(sb,
 267                                        bg_ref.block_group,
 268                                        bitmap_block.data)) {
 269                         ext4_dbg(DEBUG_BALLOC,
 270                                 DBG_WARN "Bitmap checksum failed."
 271                                 "Group: %" PRIu32"\n",
 272                                 bg_ref.index);
 273                 }
 274
 275                 uint32_t free_cnt =
 276                     ext4_sb_get_block_size(sb) * 8 - index_in_group_first;
 277
 278                 /*If last block, free only count blocks*/
 279                 free_cnt = count > free_cnt ? free_cnt : count;
 280
 281                 /* Modify bitmap */
 282                 ext4_bmap_bits_free(bitmap_block.data, index_in_group_first,
 283                                     free_cnt);
 284                 ext4_balloc_set_bitmap_csum(sb, bg_ref.block_group,
 285                                             bitmap_block.data);
 286                 bitmap_block.dirty = true;
 287
 288                 count -= free_cnt;
 289                 first += free_cnt;
 290
 291                 /* Release block with bitmap */
 292                 rc = ext4_block_set(fs->bdev, &bitmap_block);
 293                 if (rc != EOK) {
 294                         ext4_fs_put_block_group_ref(&bg_ref);
 295                         return rc;
 296                 }
 297
 298                 uint32_t block_size = ext4_sb_get_block_size(sb);
 299
 300                 /* Update superblock free blocks count */
 301                 uint64_t sb_free_blocks = ext4_sb_get_free_blocks_cnt(sb);
 302                 sb_free_blocks += free_cnt;
 303                 ext4_sb_set_free_blocks_cnt(sb, sb_free_blocks);
 304
 305                 /* Update inode blocks count */
 306                 uint64_t ino_blocks =
 307                     ext4_inode_get_blocks_count(sb, inode_ref->inode);
 308                 ino_blocks -= free_cnt * (block_size / EXT4_INODE_BLOCK_SIZE);
 309                 ext4_inode_set_blocks_count(sb, inode_ref->inode, ino_blocks);
 310                 inode_ref->dirty = true;
 311
 312                 /* Update block group free blocks count */
 313                 uint32_t free_blocks =
 314                     ext4_bg_get_free_blocks_count(bg_ref.block_group, sb);
 315                 free_blocks += free_cnt;
 316                 ext4_bg_set_free_blocks_count(bg_ref.block_group, sb,
 317                                               free_blocks);
 318                 bg_ref.dirty = true;
 319
 320                 /* Release block group reference */
 321                 rc = ext4_fs_put_block_group_ref(&bg_ref);
 322                 if (rc != EOK)
 323                         break;
 324
 325                 block_group_first++;
 326         }
 327
 328         /*All blocks should be released*/
 329         ext4_assert(count == 0);
 330         return rc;
 331 }
 332
 333 int ext4_balloc_alloc_block(struct ext4_inode_ref *inode_ref,
 334                             ext4_fsblk_t goal,
 335                             ext4_fsblk_t *fblock)
 336 {
 337         ext4_fsblk_t allocated_block = 0;
 338         ext4_fsblk_t bitmap_block_addr;
 339         uint32_t rel_block_idx = 0;
 340         uint64_t free_blocks;
 341         struct ext4_block bitmap_block;
 342         int rc;
 343
 344         struct ext4_sblock *sb = &inode_ref->fs->sb;
 345
 346         /* Load block group number for goal and relative index */
 347         uint32_t block_group = ext4_balloc_get_bgid_of_block(sb, goal);
 348         uint32_t index_in_group = ext4_fs_baddr2_index_in_group(sb, goal);
 349
 350         /* Load block group reference */
 351         struct ext4_block_group_ref bg_ref;
 352         rc = ext4_fs_get_block_group_ref(inode_ref->fs, block_group, &bg_ref);
 353         if (rc != EOK)
 354                 return rc;
 355
 356         free_blocks = ext4_bg_get_free_blocks_count(bg_ref.block_group, sb);
 357         if (free_blocks == 0) {
 358                 /* This group has no free blocks */
 359                 goto goal_failed;
 360         }
 361
 362         /* Compute indexes */
 363         ext4_fsblk_t first_in_group = ext4_balloc_get_block_of_bgid(sb, bg_ref.index);
 364
 365         uint32_t first_in_group_index =
 366             ext4_fs_baddr2_index_in_group(sb, first_in_group);
 367
 368         if (index_in_group < first_in_group_index)
 369                 index_in_group = first_in_group_index;
 370
 371         /* Load block with bitmap */
 372         bitmap_block_addr = ext4_bg_get_block_bitmap(bg_ref.block_group, sb);
 373
 374         rc = ext4_block_get(inode_ref->fs->bdev, &bitmap_block,
 375                             bitmap_block_addr);
 376         if (rc != EOK) {
 377                 ext4_fs_put_block_group_ref(&bg_ref);
 378                 return rc;
 379         }
 380
 381         if (!ext4_balloc_verify_bitmap_csum(sb,
 382                                bg_ref.block_group,
 383                                bitmap_block.data)) {
 384                 ext4_dbg(DEBUG_BALLOC,
 385                         DBG_WARN "Bitmap checksum failed."
 386                         "Group: %" PRIu32"\n",
 387                         bg_ref.index);
 388         }
 389
 390         /* Check if goal is free */
 391         if (ext4_bmap_is_bit_clr(bitmap_block.data, index_in_group)) {
 392                 ext4_bmap_bit_set(bitmap_block.data, index_in_group);
 393                 ext4_balloc_set_bitmap_csum(sb, bg_ref.block_group,
 394                                             bitmap_block.data);
 395                 bitmap_block.dirty = true;
 396                 rc = ext4_block_set(inode_ref->fs->bdev, &bitmap_block);
 397                 if (rc != EOK) {
 398                         ext4_fs_put_block_group_ref(&bg_ref);
 399                         return rc;
 400                 }
 401
 402                 allocated_block = ext4_fs_index_in_group2_baddr(
 403                     sb, index_in_group, block_group);
 404
 405                 goto success;
 406         }
 407
 408         uint32_t blocks_in_group = ext4_blocks_in_group_cnt(sb, block_group);
 409
 410         uint32_t end_idx = (index_in_group + 63) & ~63;
 411         if (end_idx > blocks_in_group)
 412                 end_idx = blocks_in_group;
 413
 414         /* Try to find free block near to goal */
 415         uint32_t tmp_idx;
 416         for (tmp_idx = index_in_group + 1; tmp_idx < end_idx; ++tmp_idx) {
 417                 if (ext4_bmap_is_bit_clr(bitmap_block.data, tmp_idx)) {
 418                         ext4_bmap_bit_set(bitmap_block.data, tmp_idx);
 419
 420                         ext4_balloc_set_bitmap_csum(sb, bg_ref.block_group,
 421                                                     bitmap_block.data);
 422                         bitmap_block.dirty = true;
 423                         rc = ext4_block_set(inode_ref->fs->bdev, &bitmap_block);
 424                         if (rc != EOK)
 425                                 return rc;
 426
 427                         allocated_block = ext4_fs_index_in_group2_baddr(
 428                             sb, tmp_idx, block_group);
 429
 430                         goto success;
 431                 }
 432         }
 433
 434         /* Find free bit in bitmap */
 435         rc = ext4_bmap_bit_find_clr(bitmap_block.data, index_in_group,
 436                                     blocks_in_group, &rel_block_idx);
 437         if (rc == EOK) {
 438                 ext4_bmap_bit_set(bitmap_block.data, rel_block_idx);
 439                 ext4_balloc_set_bitmap_csum(sb, bg_ref.block_group,
 440                                             bitmap_block.data);
 441                 bitmap_block.dirty = true;
 442                 rc = ext4_block_set(inode_ref->fs->bdev, &bitmap_block);
 443                 if (rc != EOK)
 444                         return rc;
 445
 446                 allocated_block = ext4_fs_index_in_group2_baddr(
 447                     sb, rel_block_idx, block_group);
 448
 449                 goto success;
 450         }
 451
 452         /* No free block found yet */
 453         rc = ext4_block_set(inode_ref->fs->bdev, &bitmap_block);
 454         if (rc != EOK) {
 455                 ext4_fs_put_block_group_ref(&bg_ref);
 456                 return rc;
 457         }
 458
 459 goal_failed:
 460
 461         rc = ext4_fs_put_block_group_ref(&bg_ref);
 462         if (rc != EOK)
 463                 return rc;
 464
 465         /* Try other block groups */
 466         uint32_t block_group_count = ext4_block_group_cnt(sb);
 467
 468         uint32_t bgid = (block_group + 1) % block_group_count;
 469         uint32_t count = block_group_count;
 470
 471         while (count > 0) {
 472                 rc = ext4_fs_get_block_group_ref(inode_ref->fs, bgid, &bg_ref);
 473                 if (rc != EOK)
 474                         return rc;
 475
 476                 free_blocks =
 477                     ext4_bg_get_free_blocks_count(bg_ref.block_group, sb);
 478                 if (free_blocks == 0) {
 479                         /* This group has no free blocks */
 480                         goto next_group;
 481                 }
 482
 483                 /* Load block with bitmap */
 484                 bitmap_block_addr =
 485                     ext4_bg_get_block_bitmap(bg_ref.block_group, sb);
 486
 487                 rc = ext4_block_get(inode_ref->fs->bdev, &bitmap_block,
 488                                     bitmap_block_addr);
 489
 490                 if (rc != EOK) {
 491                         ext4_fs_put_block_group_ref(&bg_ref);
 492                         return rc;
 493                 }
 494
 495                 if (!ext4_balloc_verify_bitmap_csum(sb,
 496                                        bg_ref.block_group,
 497                                        bitmap_block.data)) {
 498                         ext4_dbg(DEBUG_BALLOC,
 499                                 DBG_WARN "Bitmap checksum failed."
 500                                 "Group: %" PRIu32"\n",
 501                                 bg_ref.index);
 502                 }
 503
 504                 /* Compute indexes */
 505                 first_in_group = ext4_balloc_get_block_of_bgid(sb, bgid);
 506                 index_in_group =
 507                     ext4_fs_baddr2_index_in_group(sb, first_in_group);
 508                 blocks_in_group = ext4_blocks_in_group_cnt(sb, bgid);
 509
 510                 first_in_group_index =
 511                     ext4_fs_baddr2_index_in_group(sb, first_in_group);
 512
 513                 if (index_in_group < first_in_group_index)
 514                         index_in_group = first_in_group_index;
 515
 516                 rc = ext4_bmap_bit_find_clr(bitmap_block.data, index_in_group,
 517                                             blocks_in_group, &rel_block_idx);
 518
 519                 if (rc == EOK) {
 520
 521                         ext4_bmap_bit_set(bitmap_block.data, rel_block_idx);
 522
 523                         ext4_balloc_set_bitmap_csum(sb, bg_ref.block_group,
 524                                                     bitmap_block.data);
 525                         bitmap_block.dirty = true;
 526                         rc = ext4_block_set(inode_ref->fs->bdev, &bitmap_block);
 527                         if (rc != EOK) {
 528                                 ext4_fs_put_block_group_ref(&bg_ref);
 529                                 return rc;
 530                         }
 531
 532                         allocated_block = ext4_fs_index_in_group2_baddr(
 533                             sb, rel_block_idx, bgid);
 534
 535                         goto success;
 536                 }
 537
 538                 rc = ext4_block_set(inode_ref->fs->bdev, &bitmap_block);
 539                 if (rc != EOK) {
 540                         ext4_fs_put_block_group_ref(&bg_ref);
 541                         return rc;
 542                 }
 543
 544         next_group:
 545                 rc = ext4_fs_put_block_group_ref(&bg_ref);
 546                 if (rc != EOK) {
 547                         return rc;
 548                 }
 549
 550                 /* Goto next group */
 551                 bgid = (bgid + 1) % block_group_count;
 552                 count--;
 553         }
 554
 555         return ENOSPC;
 556
 557 success:
 558     /* Empty command - because of syntax */
 559     ;
 560
 561         uint32_t block_size = ext4_sb_get_block_size(sb);
 562
 563         /* Update superblock free blocks count */
 564         uint64_t sb_free_blocks = ext4_sb_get_free_blocks_cnt(sb);
 565         sb_free_blocks--;
 566         ext4_sb_set_free_blocks_cnt(sb, sb_free_blocks);
 567
 568         /* Update inode blocks (different block size!) count */
 569         uint64_t ino_blocks = ext4_inode_get_blocks_count(sb, inode_ref->inode);
 570         ino_blocks += block_size / EXT4_INODE_BLOCK_SIZE;
 571         ext4_inode_set_blocks_count(sb, inode_ref->inode, ino_blocks);
 572         inode_ref->dirty = true;
 573
 574         /* Update block group free blocks count */
 575         uint64_t bg_free_blocks =
 576             ext4_bg_get_free_blocks_count(bg_ref.block_group, sb);
 577         bg_free_blocks--;
 578         ext4_bg_set_free_blocks_count(bg_ref.block_group, sb, bg_free_blocks);
 579
 580         bg_ref.dirty = true;
 581
 582         rc = ext4_fs_put_block_group_ref(&bg_ref);
 583
 584         *fblock = allocated_block;
 585         return rc;
 586 }
 587
 588 int ext4_balloc_try_alloc_block(struct ext4_inode_ref *inode_ref,
 589                                 ext4_fsblk_t baddr, bool *free)
 590 {
 591         int rc;
 592
 593         struct ext4_fs *fs = inode_ref->fs;
 594         struct ext4_sblock *sb = &fs->sb;
 595
 596         /* Compute indexes */
 597         uint32_t block_group = ext4_balloc_get_bgid_of_block(sb, baddr);
 598         uint32_t index_in_group = ext4_fs_baddr2_index_in_group(sb, baddr);
 599
 600         /* Load block group reference */
 601         struct ext4_block_group_ref bg_ref;
 602         rc = ext4_fs_get_block_group_ref(fs, block_group, &bg_ref);
 603         if (rc != EOK)
 604                 return rc;
 605
 606         /* Load block with bitmap */
 607         ext4_fsblk_t bitmap_block_addr =
 608             ext4_bg_get_block_bitmap(bg_ref.block_group, sb);
 609
 610         struct ext4_block bitmap_block;
 611
 612         rc = ext4_block_get(fs->bdev, &bitmap_block, bitmap_block_addr);
 613         if (rc != EOK) {
 614                 ext4_fs_put_block_group_ref(&bg_ref);
 615                 return rc;
 616         }
 617
 618         if (!ext4_balloc_verify_bitmap_csum(sb,
 619                                bg_ref.block_group,
 620                                bitmap_block.data)) {
 621                 ext4_dbg(DEBUG_BALLOC,
 622                         DBG_WARN "Bitmap checksum failed."
 623                         "Group: %" PRIu32"\n",
 624                         bg_ref.index);
 625         }
 626
 627         /* Check if block is free */
 628         *free = ext4_bmap_is_bit_clr(bitmap_block.data, index_in_group);
 629
 630         /* Allocate block if possible */
 631         if (*free) {
 632                 ext4_bmap_bit_set(bitmap_block.data, index_in_group);
 633                 ext4_balloc_set_bitmap_csum(sb, bg_ref.block_group,
 634                                             bitmap_block.data);
 635                 bitmap_block.dirty = true;
 636         }
 637
 638         /* Release block with bitmap */
 639         rc = ext4_block_set(fs->bdev, &bitmap_block);
 640         if (rc != EOK) {
 641                 /* Error in saving bitmap */
 642                 ext4_fs_put_block_group_ref(&bg_ref);
 643                 return rc;
 644         }
 645
 646         /* If block is not free, return */
 647         if (!(*free))
 648                 goto terminate;
 649
 650         uint32_t block_size = ext4_sb_get_block_size(sb);
 651
 652         /* Update superblock free blocks count */
 653         uint64_t sb_free_blocks = ext4_sb_get_free_blocks_cnt(sb);
 654         sb_free_blocks--;
 655         ext4_sb_set_free_blocks_cnt(sb, sb_free_blocks);
 656
 657         /* Update inode blocks count */
 658         uint64_t ino_blocks = ext4_inode_get_blocks_count(sb, inode_ref->inode);
 659         ino_blocks += block_size / EXT4_INODE_BLOCK_SIZE;
 660         ext4_inode_set_blocks_count(sb, inode_ref->inode, ino_blocks);
 661         inode_ref->dirty = true;
 662
 663         /* Update block group free blocks count */
 664         uint32_t free_blocks =
 665             ext4_bg_get_free_blocks_count(bg_ref.block_group, sb);
 666         free_blocks--;
 667         ext4_bg_set_free_blocks_count(bg_ref.block_group, sb, free_blocks);
 668
 669         bg_ref.dirty = true;
 670
 671 terminate:
 672         return ext4_fs_put_block_group_ref(&bg_ref);
 673 }
 674
 675 /**
 676  * @}
 677  */