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_trans_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_trans_set_block_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         rc = ext4_trans_try_revoke_block(fs->bdev, baddr);
 215         if (rc != EOK) {
 216                 bg_ref.dirty = false;
 217                 ext4_fs_put_block_group_ref(&bg_ref);
 218                 return rc;
 219         }
 220         ext4_bcache_invalidate_lba(fs->bdev->bc, baddr, 1);
 221         /* Release block group reference */
 222         return ext4_fs_put_block_group_ref(&bg_ref);
 223 }
 224
 225 int ext4_balloc_free_blocks(struct ext4_inode_ref *inode_ref,
 226                             ext4_fsblk_t first, uint32_t count)
 227 {
 228         int rc = EOK;
 229         struct ext4_fs *fs = inode_ref->fs;
 230         struct ext4_sblock *sb = &fs->sb;
 231
 232         /* Compute indexes */
 233         uint32_t bg_first = ext4_balloc_get_bgid_of_block(sb, first);
 234
 235         /* Compute indexes */
 236         uint32_t bg_last = ext4_balloc_get_bgid_of_block(sb, first + count - 1);
 237
 238         if (!ext4_sb_feature_incom(sb, EXT4_FINCOM_FLEX_BG)) {
 239                 /*It is not possible without flex_bg that blocks are continuous
 240                  * and and last block belongs to other bg.*/
 241                 if (bg_last != bg_first) {
 242                         ext4_dbg(DEBUG_BALLOC, DBG_WARN "FLEX_BG: disabled & "
 243                                 "bg_last: %"PRIu32" bg_first: %"PRIu32"\n",
 244                                 bg_last, bg_first);
 245                 }
 246         }
 247
 248         /* Load block group reference */
 249         struct ext4_block_group_ref bg_ref;
 250         while (bg_first <= bg_last) {
 251
 252                 rc = ext4_fs_get_block_group_ref(fs, bg_first, &bg_ref);
 253                 if (rc != EOK)
 254                         return rc;
 255
 256                 struct ext4_bgroup *bg = bg_ref.block_group;
 257
 258                 uint32_t idx_in_bg_first;
 259                 idx_in_bg_first = ext4_fs_addr_to_idx_bg(sb, first);
 260
 261                 /* Load block with bitmap */
 262                 ext4_fsblk_t bitmap_blk = ext4_bg_get_block_bitmap(bg, sb);
 263
 264                 struct ext4_block blk;
 265                 rc = ext4_trans_block_get(fs->bdev, &blk, bitmap_blk);
 266                 if (rc != EOK) {
 267                         ext4_fs_put_block_group_ref(&bg_ref);
 268                         return rc;
 269                 }
 270
 271                 if (!ext4_balloc_verify_bitmap_csum(sb, bg, blk.data)) {
 272                         ext4_dbg(DEBUG_BALLOC,
 273                                 DBG_WARN "Bitmap checksum failed."
 274                                 "Group: %" PRIu32"\n",
 275                                 bg_ref.index);
 276                 }
 277                 uint32_t free_cnt;
 278                 free_cnt = ext4_sb_get_block_size(sb) * 8 - idx_in_bg_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(blk.data, idx_in_bg_first, free_cnt);
 285                 ext4_balloc_set_bitmap_csum(sb, bg, blk.data);
 286                 ext4_trans_set_block_dirty(blk.buf);
 287
 288                 count -= free_cnt;
 289                 first += free_cnt;
 290
 291                 /* Release block with bitmap */
 292                 rc = ext4_block_set(fs->bdev, &blk);
 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                 ino_blocks = 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                 free_blocks = ext4_bg_get_free_blocks_count(bg, sb);
 315                 free_blocks += free_cnt;
 316                 ext4_bg_set_free_blocks_count(bg, sb, free_blocks);
 317                 bg_ref.dirty = true;
 318
 319                 /* Release block group reference */
 320                 rc = ext4_fs_put_block_group_ref(&bg_ref);
 321                 if (rc != EOK)
 322                         break;
 323
 324                 bg_first++;
 325         }
 326
 327         uint32_t i;
 328         for (i = 0;i < count;i++) {
 329                 rc = ext4_trans_try_revoke_block(fs->bdev, first + i);
 330                 if (rc != EOK)
 331                         return rc;
 332
 333         }
 334
 335         ext4_bcache_invalidate_lba(fs->bdev->bc, first, count);
 336         /*All blocks should be released*/
 337         ext4_assert(count == 0);
 338         return rc;
 339 }
 340
 341 int ext4_balloc_alloc_block(struct ext4_inode_ref *inode_ref,
 342                             ext4_fsblk_t goal,
 343                             ext4_fsblk_t *fblock)
 344 {
 345         ext4_fsblk_t alloc = 0;
 346         ext4_fsblk_t bmp_blk_adr;
 347         uint32_t rel_blk_idx = 0;
 348         uint64_t free_blocks;
 349         int r;
 350         struct ext4_sblock *sb = &inode_ref->fs->sb;
 351
 352         /* Load block group number for goal and relative index */
 353         uint32_t bg_id = ext4_balloc_get_bgid_of_block(sb, goal);
 354         uint32_t idx_in_bg = ext4_fs_addr_to_idx_bg(sb, goal);
 355
 356         struct ext4_block b;
 357         struct ext4_block_group_ref bg_ref;
 358
 359         /* Load block group reference */
 360         r = ext4_fs_get_block_group_ref(inode_ref->fs, bg_id, &bg_ref);
 361         if (r != EOK)
 362                 return r;
 363
 364         struct ext4_bgroup *bg = bg_ref.block_group;
 365
 366         free_blocks = ext4_bg_get_free_blocks_count(bg_ref.block_group, sb);
 367         if (free_blocks == 0) {
 368                 /* This group has no free blocks */
 369                 goto goal_failed;
 370         }
 371
 372         /* Compute indexes */
 373         ext4_fsblk_t first_in_bg;
 374         first_in_bg = ext4_balloc_get_block_of_bgid(sb, bg_ref.index);
 375
 376         uint32_t first_in_bg_index;
 377         first_in_bg_index = ext4_fs_addr_to_idx_bg(sb, first_in_bg);
 378
 379         if (idx_in_bg < first_in_bg_index)
 380                 idx_in_bg = first_in_bg_index;
 381
 382         /* Load block with bitmap */
 383         bmp_blk_adr = ext4_bg_get_block_bitmap(bg_ref.block_group, sb);
 384
 385         r = ext4_trans_block_get(inode_ref->fs->bdev, &b, bmp_blk_adr);
 386         if (r != EOK) {
 387                 ext4_fs_put_block_group_ref(&bg_ref);
 388                 return r;
 389         }
 390
 391         if (!ext4_balloc_verify_bitmap_csum(sb, bg, b.data)) {
 392                 ext4_dbg(DEBUG_BALLOC,
 393                         DBG_WARN "Bitmap checksum failed."
 394                         "Group: %" PRIu32"\n",
 395                         bg_ref.index);
 396         }
 397
 398         /* Check if goal is free */
 399         if (ext4_bmap_is_bit_clr(b.data, idx_in_bg)) {
 400                 ext4_bmap_bit_set(b.data, idx_in_bg);
 401                 ext4_balloc_set_bitmap_csum(sb, bg_ref.block_group,
 402                                             b.data);
 403                 ext4_trans_set_block_dirty(b.buf);
 404                 r = ext4_block_set(inode_ref->fs->bdev, &b);
 405                 if (r != EOK) {
 406                         ext4_fs_put_block_group_ref(&bg_ref);
 407                         return r;
 408                 }
 409
 410                 alloc = ext4_fs_bg_idx_to_addr(sb, idx_in_bg, bg_id);
 411                 goto success;
 412         }
 413
 414         uint32_t blk_in_bg = ext4_blocks_in_group_cnt(sb, bg_id);
 415
 416         uint32_t end_idx = (idx_in_bg + 63) & ~63;
 417         if (end_idx > blk_in_bg)
 418                 end_idx = blk_in_bg;
 419
 420         /* Try to find free block near to goal */
 421         uint32_t tmp_idx;
 422         for (tmp_idx = idx_in_bg + 1; tmp_idx < end_idx; ++tmp_idx) {
 423                 if (ext4_bmap_is_bit_clr(b.data, tmp_idx)) {
 424                         ext4_bmap_bit_set(b.data, tmp_idx);
 425
 426                         ext4_balloc_set_bitmap_csum(sb, bg, b.data);
 427                         ext4_trans_set_block_dirty(b.buf);
 428                         r = ext4_block_set(inode_ref->fs->bdev, &b);
 429                         if (r != EOK)
 430                                 return r;
 431
 432                         alloc = ext4_fs_bg_idx_to_addr(sb, tmp_idx, bg_id);
 433                         goto success;
 434                 }
 435         }
 436
 437         /* Find free bit in bitmap */
 438         r = ext4_bmap_bit_find_clr(b.data, idx_in_bg, blk_in_bg, &rel_blk_idx);
 439         if (r == EOK) {
 440                 ext4_bmap_bit_set(b.data, rel_blk_idx);
 441                 ext4_balloc_set_bitmap_csum(sb, bg_ref.block_group, b.data);
 442                 ext4_trans_set_block_dirty(b.buf);
 443                 r = ext4_block_set(inode_ref->fs->bdev, &b);
 444                 if (r != EOK)
 445                         return r;
 446
 447                 alloc = ext4_fs_bg_idx_to_addr(sb, rel_blk_idx, bg_id);
 448                 goto success;
 449         }
 450
 451         /* No free block found yet */
 452         r = ext4_block_set(inode_ref->fs->bdev, &b);
 453         if (r != EOK) {
 454                 ext4_fs_put_block_group_ref(&bg_ref);
 455                 return r;
 456         }
 457
 458 goal_failed:
 459
 460         r = ext4_fs_put_block_group_ref(&bg_ref);
 461         if (r != EOK)
 462                 return r;
 463
 464         /* Try other block groups */
 465         uint32_t block_group_count = ext4_block_group_cnt(sb);
 466         uint32_t bgid = (bg_id + 1) % block_group_count;
 467         uint32_t count = block_group_count;
 468
 469         while (count > 0) {
 470                 r = ext4_fs_get_block_group_ref(inode_ref->fs, bgid, &bg_ref);
 471                 if (r != EOK)
 472                         return r;
 473
 474                 struct ext4_bgroup *bg = bg_ref.block_group;
 475                 free_blocks = ext4_bg_get_free_blocks_count(bg, sb);
 476                 if (free_blocks == 0) {
 477                         /* This group has no free blocks */
 478                         goto next_group;
 479                 }
 480
 481                 /* Load block with bitmap */
 482                 bmp_blk_adr = ext4_bg_get_block_bitmap(bg, sb);
 483                 r = ext4_trans_block_get(inode_ref->fs->bdev, &b, bmp_blk_adr);
 484                 if (r != EOK) {
 485                         ext4_fs_put_block_group_ref(&bg_ref);
 486                         return r;
 487                 }
 488
 489                 if (!ext4_balloc_verify_bitmap_csum(sb, bg, b.data)) {
 490                         ext4_dbg(DEBUG_BALLOC,
 491                                 DBG_WARN "Bitmap checksum failed."
 492                                 "Group: %" PRIu32"\n",
 493                                 bg_ref.index);
 494                 }
 495
 496                 /* Compute indexes */
 497                 first_in_bg = ext4_balloc_get_block_of_bgid(sb, bgid);
 498                 idx_in_bg = ext4_fs_addr_to_idx_bg(sb, first_in_bg);
 499                 blk_in_bg = ext4_blocks_in_group_cnt(sb, bgid);
 500                 first_in_bg_index = ext4_fs_addr_to_idx_bg(sb, first_in_bg);
 501
 502                 if (idx_in_bg < first_in_bg_index)
 503                         idx_in_bg = first_in_bg_index;
 504
 505                 r = ext4_bmap_bit_find_clr(b.data, idx_in_bg, blk_in_bg,
 506                                 &rel_blk_idx);
 507                 if (r == EOK) {
 508                         ext4_bmap_bit_set(b.data, rel_blk_idx);
 509                         ext4_balloc_set_bitmap_csum(sb, bg, b.data);
 510                         ext4_trans_set_block_dirty(b.buf);
 511                         r = ext4_block_set(inode_ref->fs->bdev, &b);
 512                         if (r != EOK) {
 513                                 ext4_fs_put_block_group_ref(&bg_ref);
 514                                 return r;
 515                         }
 516
 517                         alloc = ext4_fs_bg_idx_to_addr(sb, rel_blk_idx, bgid);
 518                         goto success;
 519                 }
 520
 521                 r = ext4_block_set(inode_ref->fs->bdev, &b);
 522                 if (r != EOK) {
 523                         ext4_fs_put_block_group_ref(&bg_ref);
 524                         return r;
 525                 }
 526
 527         next_group:
 528                 r = ext4_fs_put_block_group_ref(&bg_ref);
 529                 if (r != EOK) {
 530                         return r;
 531                 }
 532
 533                 /* Goto next group */
 534                 bgid = (bgid + 1) % block_group_count;
 535                 count--;
 536         }
 537
 538         return ENOSPC;
 539
 540 success:
 541     /* Empty command - because of syntax */
 542     ;
 543
 544         uint32_t block_size = ext4_sb_get_block_size(sb);
 545
 546         /* Update superblock free blocks count */
 547         uint64_t sb_free_blocks = ext4_sb_get_free_blocks_cnt(sb);
 548         sb_free_blocks--;
 549         ext4_sb_set_free_blocks_cnt(sb, sb_free_blocks);
 550
 551         /* Update inode blocks (different block size!) count */
 552         uint64_t ino_blocks = ext4_inode_get_blocks_count(sb, inode_ref->inode);
 553         ino_blocks += block_size / EXT4_INODE_BLOCK_SIZE;
 554         ext4_inode_set_blocks_count(sb, inode_ref->inode, ino_blocks);
 555         inode_ref->dirty = true;
 556
 557         /* Update block group free blocks count */
 558
 559         uint32_t fb_cnt = ext4_bg_get_free_blocks_count(bg_ref.block_group, sb);
 560         fb_cnt--;
 561         ext4_bg_set_free_blocks_count(bg_ref.block_group, sb, fb_cnt);
 562
 563         bg_ref.dirty = true;
 564         r = ext4_fs_put_block_group_ref(&bg_ref);
 565
 566         *fblock = alloc;
 567         return r;
 568 }
 569
 570 int ext4_balloc_try_alloc_block(struct ext4_inode_ref *inode_ref,
 571                                 ext4_fsblk_t baddr, bool *free)
 572 {
 573         int rc;
 574
 575         struct ext4_fs *fs = inode_ref->fs;
 576         struct ext4_sblock *sb = &fs->sb;
 577
 578         /* Compute indexes */
 579         uint32_t block_group = ext4_balloc_get_bgid_of_block(sb, baddr);
 580         uint32_t index_in_group = ext4_fs_addr_to_idx_bg(sb, baddr);
 581
 582         /* Load block group reference */
 583         struct ext4_block_group_ref bg_ref;
 584         rc = ext4_fs_get_block_group_ref(fs, block_group, &bg_ref);
 585         if (rc != EOK)
 586                 return rc;
 587
 588         /* Load block with bitmap */
 589         ext4_fsblk_t bmp_blk_addr;
 590         bmp_blk_addr = ext4_bg_get_block_bitmap(bg_ref.block_group, sb);
 591
 592         struct ext4_block b;
 593         rc = ext4_trans_block_get(fs->bdev, &b, bmp_blk_addr);
 594         if (rc != EOK) {
 595                 ext4_fs_put_block_group_ref(&bg_ref);
 596                 return rc;
 597         }
 598
 599         if (!ext4_balloc_verify_bitmap_csum(sb, bg_ref.block_group, b.data)) {
 600                 ext4_dbg(DEBUG_BALLOC,
 601                         DBG_WARN "Bitmap checksum failed."
 602                         "Group: %" PRIu32"\n",
 603                         bg_ref.index);
 604         }
 605
 606         /* Check if block is free */
 607         *free = ext4_bmap_is_bit_clr(b.data, index_in_group);
 608
 609         /* Allocate block if possible */
 610         if (*free) {
 611                 ext4_bmap_bit_set(b.data, index_in_group);
 612                 ext4_balloc_set_bitmap_csum(sb, bg_ref.block_group, b.data);
 613                 ext4_trans_set_block_dirty(b.buf);
 614         }
 615
 616         /* Release block with bitmap */
 617         rc = ext4_block_set(fs->bdev, &b);
 618         if (rc != EOK) {
 619                 /* Error in saving bitmap */
 620                 ext4_fs_put_block_group_ref(&bg_ref);
 621                 return rc;
 622         }
 623
 624         /* If block is not free, return */
 625         if (!(*free))
 626                 goto terminate;
 627
 628         uint32_t block_size = ext4_sb_get_block_size(sb);
 629
 630         /* Update superblock free blocks count */
 631         uint64_t sb_free_blocks = ext4_sb_get_free_blocks_cnt(sb);
 632         sb_free_blocks--;
 633         ext4_sb_set_free_blocks_cnt(sb, sb_free_blocks);
 634
 635         /* Update inode blocks count */
 636         uint64_t ino_blocks = ext4_inode_get_blocks_count(sb, inode_ref->inode);
 637         ino_blocks += block_size / EXT4_INODE_BLOCK_SIZE;
 638         ext4_inode_set_blocks_count(sb, inode_ref->inode, ino_blocks);
 639         inode_ref->dirty = true;
 640
 641         /* Update block group free blocks count */
 642         uint32_t fb_cnt = ext4_bg_get_free_blocks_count(bg_ref.block_group, sb);
 643         fb_cnt--;
 644         ext4_bg_set_free_blocks_count(bg_ref.block_group, sb, fb_cnt);
 645
 646         bg_ref.dirty = true;
 647
 648 terminate:
 649         return ext4_fs_put_block_group_ref(&bg_ref);
 650 }
 651
 652 /**
 653  * @}
 654  */