src/ext4_fs.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 /** @addtogroup lwext4
  34  * @{
  35  */
  36 /**
  37  * @file  ext4_fs.c
  38  * @brief More complex filesystem functions.
  39  */
  40
  41 #include "ext4_config.h"
  42 #include "ext4_types.h"
  43 #include "ext4_misc.h"
  44 #include "ext4_errno.h"
  45 #include "ext4_debug.h"
  46
  47 #include "ext4_trans.h"
  48 #include "ext4_fs.h"
  49 #include "ext4_blockdev.h"
  50 #include "ext4_super.h"
  51 #include "ext4_crc32.h"
  52 #include "ext4_block_group.h"
  53 #include "ext4_balloc.h"
  54 #include "ext4_bitmap.h"
  55 #include "ext4_inode.h"
  56 #include "ext4_ialloc.h"
  57 #include "ext4_extent.h"
  58
  59 #include <string.h>
  60
  61 int ext4_fs_init(struct ext4_fs *fs, struct ext4_blockdev *bdev,
  62                  bool read_only)
  63 {
  64         int r, i;
  65         uint16_t tmp;
  66         uint32_t bsize;
  67
  68         ext4_assert(fs && bdev);
  69
  70         fs->bdev = bdev;
  71
  72         fs->read_only = read_only;
  73
  74         r = ext4_sb_read(fs->bdev, &fs->sb);
  75         if (r != EOK)
  76                 return r;
  77
  78         if (!ext4_sb_check(&fs->sb))
  79                 return ENOTSUP;
  80
  81         bsize = ext4_sb_get_block_size(&fs->sb);
  82         if (bsize > EXT4_MAX_BLOCK_SIZE)
  83                 return ENXIO;
  84
  85         r = ext4_fs_check_features(fs, &read_only);
  86         if (r != EOK)
  87                 return r;
  88
  89         if (read_only)
  90                 fs->read_only = read_only;
  91
  92         /* Compute limits for indirect block levels */
  93         uint32_t blocks_id = bsize / sizeof(uint32_t);
  94
  95         fs->inode_block_limits[0] = EXT4_INODE_DIRECT_BLOCK_COUNT;
  96         fs->inode_blocks_per_level[0] = 1;
  97
  98         for (i = 1; i < 4; i++) {
  99                 fs->inode_blocks_per_level[i] =
 100                     fs->inode_blocks_per_level[i - 1] * blocks_id;
 101                 fs->inode_block_limits[i] = fs->inode_block_limits[i - 1] +
 102                                             fs->inode_blocks_per_level[i];
 103         }
 104
 105         /*Validate FS*/
 106         tmp = ext4_get16(&fs->sb, state);
 107         if (tmp & EXT4_SUPERBLOCK_STATE_ERROR_FS)
 108                 ext4_dbg(DEBUG_FS, DBG_WARN
 109                                 "last umount error: superblock fs_error flag\n");
 110
 111
 112         if (!fs->read_only) {
 113                 /* Mark system as mounted */
 114                 ext4_set16(&fs->sb, state, EXT4_SUPERBLOCK_STATE_ERROR_FS);
 115                 r = ext4_sb_write(fs->bdev, &fs->sb);
 116                 if (r != EOK)
 117                         return r;
 118
 119                 /*Update mount count*/
 120                 ext4_set16(&fs->sb, mount_count, ext4_get16(&fs->sb, mount_count) + 1);
 121         }
 122
 123         return r;
 124 }
 125
 126 int ext4_fs_fini(struct ext4_fs *fs)
 127 {
 128         ext4_assert(fs);
 129
 130         /*Set superblock state*/
 131         ext4_set16(&fs->sb, state, EXT4_SUPERBLOCK_STATE_VALID_FS);
 132
 133         if (!fs->read_only)
 134                 return ext4_sb_write(fs->bdev, &fs->sb);
 135
 136         return EOK;
 137 }
 138
 139 static void ext4_fs_debug_features_inc(uint32_t features_incompatible)
 140 {
 141         if (features_incompatible & EXT4_FINCOM_COMPRESSION)
 142                 ext4_dbg(DEBUG_FS, DBG_NONE "compression\n");
 143         if (features_incompatible & EXT4_FINCOM_FILETYPE)
 144                 ext4_dbg(DEBUG_FS, DBG_NONE "filetype\n");
 145         if (features_incompatible & EXT4_FINCOM_RECOVER)
 146                 ext4_dbg(DEBUG_FS, DBG_NONE "recover\n");
 147         if (features_incompatible & EXT4_FINCOM_JOURNAL_DEV)
 148                 ext4_dbg(DEBUG_FS, DBG_NONE "journal_dev\n");
 149         if (features_incompatible & EXT4_FINCOM_META_BG)
 150                 ext4_dbg(DEBUG_FS, DBG_NONE "meta_bg\n");
 151         if (features_incompatible & EXT4_FINCOM_EXTENTS)
 152                 ext4_dbg(DEBUG_FS, DBG_NONE "extents\n");
 153         if (features_incompatible & EXT4_FINCOM_64BIT)
 154                 ext4_dbg(DEBUG_FS, DBG_NONE "64bit\n");
 155         if (features_incompatible & EXT4_FINCOM_MMP)
 156                 ext4_dbg(DEBUG_FS, DBG_NONE "mnp\n");
 157         if (features_incompatible & EXT4_FINCOM_FLEX_BG)
 158                 ext4_dbg(DEBUG_FS, DBG_NONE "flex_bg\n");
 159         if (features_incompatible & EXT4_FINCOM_EA_INODE)
 160                 ext4_dbg(DEBUG_FS, DBG_NONE "ea_inode\n");
 161         if (features_incompatible & EXT4_FINCOM_DIRDATA)
 162                 ext4_dbg(DEBUG_FS, DBG_NONE "dirdata\n");
 163         if (features_incompatible & EXT4_FINCOM_BG_USE_META_CSUM)
 164                 ext4_dbg(DEBUG_FS, DBG_NONE "meta_csum\n");
 165         if (features_incompatible & EXT4_FINCOM_LARGEDIR)
 166                 ext4_dbg(DEBUG_FS, DBG_NONE "largedir\n");
 167         if (features_incompatible & EXT4_FINCOM_INLINE_DATA)
 168                 ext4_dbg(DEBUG_FS, DBG_NONE "inline_data\n");
 169 }
 170 static void ext4_fs_debug_features_comp(uint32_t features_compatible)
 171 {
 172         if (features_compatible & EXT4_FCOM_DIR_PREALLOC)
 173                 ext4_dbg(DEBUG_FS, DBG_NONE "dir_prealloc\n");
 174         if (features_compatible & EXT4_FCOM_IMAGIC_INODES)
 175                 ext4_dbg(DEBUG_FS, DBG_NONE "imagic_inodes\n");
 176         if (features_compatible & EXT4_FCOM_HAS_JOURNAL)
 177                 ext4_dbg(DEBUG_FS, DBG_NONE "has_journal\n");
 178         if (features_compatible & EXT4_FCOM_EXT_ATTR)
 179                 ext4_dbg(DEBUG_FS, DBG_NONE "ext_attr\n");
 180         if (features_compatible & EXT4_FCOM_RESIZE_INODE)
 181                 ext4_dbg(DEBUG_FS, DBG_NONE "resize_inode\n");
 182         if (features_compatible & EXT4_FCOM_DIR_INDEX)
 183                 ext4_dbg(DEBUG_FS, DBG_NONE "dir_index\n");
 184 }
 185
 186 static void ext4_fs_debug_features_ro(uint32_t features_ro)
 187 {
 188         if (features_ro & EXT4_FRO_COM_SPARSE_SUPER)
 189                 ext4_dbg(DEBUG_FS, DBG_NONE "sparse_super\n");
 190         if (features_ro & EXT4_FRO_COM_LARGE_FILE)
 191                 ext4_dbg(DEBUG_FS, DBG_NONE "large_file\n");
 192         if (features_ro & EXT4_FRO_COM_BTREE_DIR)
 193                 ext4_dbg(DEBUG_FS, DBG_NONE "btree_dir\n");
 194         if (features_ro & EXT4_FRO_COM_HUGE_FILE)
 195                 ext4_dbg(DEBUG_FS, DBG_NONE "huge_file\n");
 196         if (features_ro & EXT4_FRO_COM_GDT_CSUM)
 197                 ext4_dbg(DEBUG_FS, DBG_NONE "gtd_csum\n");
 198         if (features_ro & EXT4_FRO_COM_DIR_NLINK)
 199                 ext4_dbg(DEBUG_FS, DBG_NONE "dir_nlink\n");
 200         if (features_ro & EXT4_FRO_COM_EXTRA_ISIZE)
 201                 ext4_dbg(DEBUG_FS, DBG_NONE "extra_isize\n");
 202         if (features_ro & EXT4_FRO_COM_QUOTA)
 203                 ext4_dbg(DEBUG_FS, DBG_NONE "quota\n");
 204         if (features_ro & EXT4_FRO_COM_BIGALLOC)
 205                 ext4_dbg(DEBUG_FS, DBG_NONE "bigalloc\n");
 206         if (features_ro & EXT4_FRO_COM_METADATA_CSUM)
 207                 ext4_dbg(DEBUG_FS, DBG_NONE "metadata_csum\n");
 208 }
 209
 210 int ext4_fs_check_features(struct ext4_fs *fs, bool *read_only)
 211 {
 212         ext4_assert(fs && read_only);
 213         uint32_t v;
 214         if (ext4_get32(&fs->sb, rev_level) == 0) {
 215                 *read_only = false;
 216                 return EOK;
 217         }
 218
 219         ext4_dbg(DEBUG_FS, DBG_INFO "sblock features_incompatible:\n");
 220         ext4_fs_debug_features_inc(ext4_get32(&fs->sb, features_incompatible));
 221
 222         ext4_dbg(DEBUG_FS, DBG_INFO "sblock features_compatible:\n");
 223         ext4_fs_debug_features_comp(ext4_get32(&fs->sb, features_compatible));
 224
 225         ext4_dbg(DEBUG_FS, DBG_INFO "sblock features_read_only:\n");
 226         ext4_fs_debug_features_ro(ext4_get32(&fs->sb, features_read_only));
 227
 228         /*Check features_incompatible*/
 229         v = (ext4_get32(&fs->sb, features_incompatible) &
 230              (~CONFIG_SUPPORTED_FINCOM));
 231         if (v) {
 232                 ext4_dbg(DEBUG_FS, DBG_ERROR
 233                                 "sblock has unsupported features incompatible:\n");
 234                 ext4_fs_debug_features_inc(v);
 235                 return ENOTSUP;
 236         }
 237
 238         /*Check features_read_only*/
 239         v = ext4_get32(&fs->sb, features_read_only);
 240         v &= ~CONFIG_SUPPORTED_FRO_COM;
 241         if (v) {
 242                 ext4_dbg(DEBUG_FS, DBG_WARN
 243                         "sblock has unsupported features read only:\n");
 244                 ext4_fs_debug_features_ro(v);
 245                 *read_only = true;
 246                 return EOK;
 247         }
 248         *read_only = false;
 249
 250         return EOK;
 251 }
 252
 253 /**@brief Determine whether the block is inside the group.
 254  * @param baddr   block address
 255  * @param bgid    block group id
 256  * @return Error code
 257  */
 258 static bool ext4_block_in_group(struct ext4_sblock *s, ext4_fsblk_t baddr,
 259                                 uint32_t bgid)
 260 {
 261         uint32_t actual_bgid;
 262         actual_bgid = ext4_balloc_get_bgid_of_block(s, baddr);
 263         if (actual_bgid == bgid)
 264                 return true;
 265         return false;
 266 }
 267
 268 /**@brief   To avoid calling the atomic setbit hundreds or thousands of times, we only
 269  *          need to use it within a single byte (to ensure we get endianness right).
 270  *          We can use memset for the rest of the bitmap as there are no other users.
 271  */
 272 static void ext4_fs_mark_bitmap_end(int start_bit, int end_bit, void *bitmap)
 273 {
 274         int i;
 275
 276         if (start_bit >= end_bit)
 277                 return;
 278
 279         for (i = start_bit; (unsigned)i < ((start_bit + 7) & ~7UL); i++)
 280                 ext4_bmap_bit_set(bitmap, i);
 281
 282         if (i < end_bit)
 283                 memset((char *)bitmap + (i >> 3), 0xff, (end_bit - i) >> 3);
 284 }
 285
 286 /**@brief Initialize block bitmap in block group.
 287  * @param bg_ref Reference to block group
 288  * @return Error code
 289  */
 290 static int ext4_fs_init_block_bitmap(struct ext4_block_group_ref *bg_ref)
 291 {
 292         struct ext4_sblock *sb = &bg_ref->fs->sb;
 293         struct ext4_bgroup *bg = bg_ref->block_group;
 294         int rc;
 295
 296         uint32_t bit, bit_max;
 297         uint32_t group_blocks;
 298         uint16_t inode_size = ext4_get16(sb, inode_size);
 299         uint32_t block_size = ext4_sb_get_block_size(sb);
 300         uint32_t inodes_per_group = ext4_get32(sb, inodes_per_group);
 301
 302         ext4_fsblk_t i;
 303         ext4_fsblk_t bmp_blk = ext4_bg_get_block_bitmap(bg, sb);
 304         ext4_fsblk_t bmp_inode = ext4_bg_get_inode_bitmap(bg, sb);
 305         ext4_fsblk_t inode_table = ext4_bg_get_inode_table_first_block(bg, sb);
 306         ext4_fsblk_t first_bg = ext4_balloc_get_block_of_bgid(sb, bg_ref->index);
 307
 308         uint32_t dsc_per_block =  block_size / ext4_sb_get_desc_size(sb);
 309
 310         bool flex_bg = ext4_sb_feature_incom(sb, EXT4_FINCOM_FLEX_BG);
 311         bool meta_bg = ext4_sb_feature_incom(sb, EXT4_FINCOM_META_BG);
 312
 313         uint32_t inode_table_bcnt = inodes_per_group * inode_size / block_size;
 314
 315         struct ext4_block block_bitmap;
 316         rc = ext4_trans_block_get_noread(bg_ref->fs->bdev, &block_bitmap, bmp_blk);
 317         if (rc != EOK)
 318                 return rc;
 319
 320         memset(block_bitmap.data, 0, block_size);
 321         bit_max = ext4_sb_is_super_in_bg(sb, bg_ref->index);
 322
 323         uint32_t count = ext4_sb_first_meta_bg(sb) * dsc_per_block;
 324         if (!meta_bg || bg_ref->index < count) {
 325                 if (bit_max) {
 326                         bit_max += ext4_bg_num_gdb(sb, bg_ref->index);
 327                         bit_max += ext4_get16(sb, s_reserved_gdt_blocks);
 328                 }
 329         } else { /* For META_BG_BLOCK_GROUPS */
 330                 bit_max += ext4_bg_num_gdb(sb, bg_ref->index);
 331         }
 332         for (bit = 0; bit < bit_max; bit++)
 333                 ext4_bmap_bit_set(block_bitmap.data, bit);
 334
 335         if (bg_ref->index == ext4_block_group_cnt(sb) - 1) {
 336                 /*
 337                  * Even though mke2fs always initialize first and last group
 338                  * if some other tool enabled the EXT4_BG_BLOCK_UNINIT we need
 339                  * to make sure we calculate the right free blocks
 340                  */
 341
 342                 group_blocks = (uint32_t)(ext4_sb_get_blocks_cnt(sb) -
 343                                           ext4_get32(sb, first_data_block) -
 344                                           ext4_get32(sb, blocks_per_group) *
 345                                           (ext4_block_group_cnt(sb) - 1));
 346         } else {
 347                 group_blocks = ext4_get32(sb, blocks_per_group);
 348         }
 349
 350         bool in_bg;
 351         in_bg = ext4_block_in_group(sb, bmp_blk, bg_ref->index);
 352         if (!flex_bg || in_bg)
 353                 ext4_bmap_bit_set(block_bitmap.data,
 354                                   (uint32_t)(bmp_blk - first_bg));
 355
 356         in_bg = ext4_block_in_group(sb, bmp_inode, bg_ref->index);
 357         if (!flex_bg || in_bg)
 358                 ext4_bmap_bit_set(block_bitmap.data,
 359                                   (uint32_t)(bmp_inode - first_bg));
 360
 361         for (i = inode_table; i < inode_table + inode_table_bcnt; i++) {
 362                 in_bg = ext4_block_in_group(sb, i, bg_ref->index);
 363                 if (!flex_bg || in_bg)
 364                         ext4_bmap_bit_set(block_bitmap.data,
 365                                           (uint32_t)(i - first_bg));
 366         }
 367         /*
 368          * Also if the number of blocks within the group is
 369          * less than the blocksize * 8 ( which is the size
 370          * of bitmap ), set rest of the block bitmap to 1
 371          */
 372         ext4_fs_mark_bitmap_end(group_blocks, block_size * 8, block_bitmap.data);
 373         ext4_trans_set_block_dirty(block_bitmap.buf);
 374
 375         ext4_balloc_set_bitmap_csum(sb, bg_ref->block_group, block_bitmap.data);
 376         bg_ref->dirty = true;
 377
 378         /* Save bitmap */
 379         return ext4_block_set(bg_ref->fs->bdev, &block_bitmap);
 380 }
 381
 382 /**@brief Initialize i-node bitmap in block group.
 383  * @param bg_ref Reference to block group
 384  * @return Error code
 385  */
 386 static int ext4_fs_init_inode_bitmap(struct ext4_block_group_ref *bg_ref)
 387 {
 388         int rc;
 389         struct ext4_sblock *sb = &bg_ref->fs->sb;
 390         struct ext4_bgroup *bg = bg_ref->block_group;
 391
 392         /* Load bitmap */
 393         ext4_fsblk_t bitmap_block_addr = ext4_bg_get_inode_bitmap(bg, sb);
 394
 395         struct ext4_block b;
 396         rc = ext4_trans_block_get_noread(bg_ref->fs->bdev, &b, bitmap_block_addr);
 397         if (rc != EOK)
 398                 return rc;
 399
 400         /* Initialize all bitmap bits to zero */
 401         uint32_t block_size = ext4_sb_get_block_size(sb);
 402         uint32_t inodes_per_group = ext4_get32(sb, inodes_per_group);
 403
 404         memset(b.data, 0, (inodes_per_group + 7) / 8);
 405
 406         uint32_t start_bit = inodes_per_group;
 407         uint32_t end_bit = block_size * 8;
 408
 409         uint32_t i;
 410         for (i = start_bit; i < ((start_bit + 7) & ~7UL); i++)
 411                 ext4_bmap_bit_set(b.data, i);
 412
 413         if (i < end_bit)
 414                 memset(b.data + (i >> 3), 0xff, (end_bit - i) >> 3);
 415
 416         ext4_trans_set_block_dirty(b.buf);
 417
 418         ext4_ialloc_set_bitmap_csum(sb, bg, b.data);
 419         bg_ref->dirty = true;
 420
 421         /* Save bitmap */
 422         return ext4_block_set(bg_ref->fs->bdev, &b);
 423 }
 424
 425 /**@brief Initialize i-node table in block group.
 426  * @param bg_ref Reference to block group
 427  * @return Error code
 428  */
 429 static int ext4_fs_init_inode_table(struct ext4_block_group_ref *bg_ref)
 430 {
 431         struct ext4_sblock *sb = &bg_ref->fs->sb;
 432         struct ext4_bgroup *bg = bg_ref->block_group;
 433
 434         uint32_t inode_size = ext4_get32(sb, inode_size);
 435         uint32_t block_size = ext4_sb_get_block_size(sb);
 436         uint32_t inodes_per_block = block_size / inode_size;
 437         uint32_t inodes_in_group = ext4_inodes_in_group_cnt(sb, bg_ref->index);
 438         uint32_t table_blocks = inodes_in_group / inodes_per_block;
 439         ext4_fsblk_t fblock;
 440
 441         if (inodes_in_group % inodes_per_block)
 442                 table_blocks++;
 443
 444         /* Compute initialization bounds */
 445         ext4_fsblk_t first_block = ext4_bg_get_inode_table_first_block(bg, sb);
 446
 447         ext4_fsblk_t last_block = first_block + table_blocks - 1;
 448
 449         /* Initialization of all itable blocks */
 450         for (fblock = first_block; fblock <= last_block; ++fblock) {
 451                 struct ext4_block b;
 452                 int rc = ext4_trans_block_get_noread(bg_ref->fs->bdev, &b, fblock);
 453                 if (rc != EOK)
 454                         return rc;
 455
 456                 memset(b.data, 0, block_size);
 457                 ext4_trans_set_block_dirty(b.buf);
 458
 459                 ext4_block_set(bg_ref->fs->bdev, &b);
 460                 if (rc != EOK)
 461                         return rc;
 462         }
 463
 464         return EOK;
 465 }
 466
 467 static ext4_fsblk_t ext4_fs_get_descriptor_block(struct ext4_sblock *s,
 468                                              uint32_t bgid,
 469                                              uint32_t dsc_per_block)
 470 {
 471         uint32_t first_meta_bg, dsc_id;
 472         int has_super = 0;
 473         dsc_id = bgid / dsc_per_block;
 474         first_meta_bg = ext4_sb_first_meta_bg(s);
 475
 476         bool meta_bg = ext4_sb_feature_incom(s, EXT4_FINCOM_META_BG);
 477
 478         if (!meta_bg || dsc_id < first_meta_bg)
 479                 return ext4_get32(s, first_data_block) + dsc_id + 1;
 480
 481         if (ext4_sb_is_super_in_bg(s, bgid))
 482                 has_super = 1;
 483
 484         return (has_super + ext4_fs_first_bg_block_no(s, bgid));
 485 }
 486
 487 /**@brief  Compute checksum of block group descriptor.
 488  * @param sb   Superblock
 489  * @param bgid Index of block group in the filesystem
 490  * @param bg   Block group to compute checksum for
 491  * @return Checksum value
 492  */
 493 static uint16_t ext4_fs_bg_checksum(struct ext4_sblock *sb, uint32_t bgid,
 494                                     struct ext4_bgroup *bg)
 495 {
 496         /* If checksum not supported, 0 will be returned */
 497         uint16_t crc = 0;
 498 #if CONFIG_META_CSUM_ENABLE
 499         /* Compute the checksum only if the filesystem supports it */
 500         if (ext4_sb_feature_ro_com(sb, EXT4_FRO_COM_METADATA_CSUM)) {
 501                 /* Use metadata_csum algorithm instead */
 502                 uint32_t le32_bgid = to_le32(bgid);
 503                 uint32_t orig_checksum, checksum;
 504
 505                 /* Preparation: temporarily set bg checksum to 0 */
 506                 orig_checksum = bg->checksum;
 507                 bg->checksum = 0;
 508
 509                 /* First calculate crc32 checksum against fs uuid */
 510                 checksum = ext4_crc32c(EXT4_CRC32_INIT, sb->uuid,
 511                                 sizeof(sb->uuid));
 512                 /* Then calculate crc32 checksum against bgid */
 513                 checksum = ext4_crc32c(checksum, &le32_bgid, sizeof(bgid));
 514                 /* Finally calculate crc32 checksum against block_group_desc */
 515                 checksum = ext4_crc32c(checksum, bg, ext4_sb_get_desc_size(sb));
 516                 bg->checksum = orig_checksum;
 517
 518                 crc = checksum & 0xFFFF;
 519                 return crc;
 520         }
 521 #endif
 522         if (ext4_sb_feature_ro_com(sb, EXT4_FRO_COM_GDT_CSUM)) {
 523                 uint8_t *base = (uint8_t *)bg;
 524                 uint8_t *checksum = (uint8_t *)&bg->checksum;
 525
 526                 uint32_t offset = (uint32_t)(checksum - base);
 527
 528                 /* Convert block group index to little endian */
 529                 uint32_t group = to_le32(bgid);
 530
 531                 /* Initialization */
 532                 crc = ext4_bg_crc16(~0, sb->uuid, sizeof(sb->uuid));
 533
 534                 /* Include index of block group */
 535                 crc = ext4_bg_crc16(crc, (uint8_t *)&group, sizeof(group));
 536
 537                 /* Compute crc from the first part (stop before checksum field)
 538                  */
 539                 crc = ext4_bg_crc16(crc, (uint8_t *)bg, offset);
 540
 541                 /* Skip checksum */
 542                 offset += sizeof(bg->checksum);
 543
 544                 /* Checksum of the rest of block group descriptor */
 545                 if ((ext4_sb_feature_incom(sb, EXT4_FINCOM_64BIT)) &&
 546                     (offset < ext4_sb_get_desc_size(sb))) {
 547
 548                         const uint8_t *start = ((uint8_t *)bg) + offset;
 549                         size_t len = ext4_sb_get_desc_size(sb) - offset;
 550                         crc = ext4_bg_crc16(crc, start, len);
 551                 }
 552         }
 553         return crc;
 554 }
 555
 556 #if CONFIG_META_CSUM_ENABLE
 557 static bool ext4_fs_verify_bg_csum(struct ext4_sblock *sb,
 558                                    uint32_t bgid,
 559                                    struct ext4_bgroup *bg)
 560 {
 561         if (!ext4_sb_feature_ro_com(sb, EXT4_FRO_COM_METADATA_CSUM))
 562                 return true;
 563
 564         return ext4_fs_bg_checksum(sb, bgid, bg) == to_le16(bg->checksum);
 565 }
 566 #else
 567 #define ext4_fs_verify_bg_csum(...) true
 568 #endif
 569
 570 int ext4_fs_get_block_group_ref(struct ext4_fs *fs, uint32_t bgid,
 571                                 struct ext4_block_group_ref *ref)
 572 {
 573         /* Compute number of descriptors, that fits in one data block */
 574         uint32_t block_size = ext4_sb_get_block_size(&fs->sb);
 575         uint32_t dsc_cnt = block_size / ext4_sb_get_desc_size(&fs->sb);
 576
 577         /* Block group descriptor table starts at the next block after
 578          * superblock */
 579         uint64_t block_id = ext4_fs_get_descriptor_block(&fs->sb, bgid, dsc_cnt);
 580
 581         uint32_t offset = (bgid % dsc_cnt) * ext4_sb_get_desc_size(&fs->sb);
 582
 583         int rc = ext4_trans_block_get(fs->bdev, &ref->block, block_id);
 584         if (rc != EOK)
 585                 return rc;
 586
 587         ref->block_group = (void *)(ref->block.data + offset);
 588         ref->fs = fs;
 589         ref->index = bgid;
 590         ref->dirty = false;
 591         struct ext4_bgroup *bg = ref->block_group;
 592
 593         if (!ext4_fs_verify_bg_csum(&fs->sb, bgid, bg)) {
 594                 ext4_dbg(DEBUG_FS,
 595                          DBG_WARN "Block group descriptor checksum failed."
 596                          "Block group index: %" PRIu32"\n",
 597                          bgid);
 598         }
 599
 600         if (ext4_bg_has_flag(bg, EXT4_BLOCK_GROUP_BLOCK_UNINIT)) {
 601                 rc = ext4_fs_init_block_bitmap(ref);
 602                 if (rc != EOK) {
 603                         ext4_block_set(fs->bdev, &ref->block);
 604                         return rc;
 605                 }
 606                 ext4_bg_clear_flag(bg, EXT4_BLOCK_GROUP_BLOCK_UNINIT);
 607                 ref->dirty = true;
 608         }
 609
 610         if (ext4_bg_has_flag(bg, EXT4_BLOCK_GROUP_INODE_UNINIT)) {
 611                 rc = ext4_fs_init_inode_bitmap(ref);
 612                 if (rc != EOK) {
 613                         ext4_block_set(ref->fs->bdev, &ref->block);
 614                         return rc;
 615                 }
 616
 617                 ext4_bg_clear_flag(bg, EXT4_BLOCK_GROUP_INODE_UNINIT);
 618
 619                 if (!ext4_bg_has_flag(bg, EXT4_BLOCK_GROUP_ITABLE_ZEROED)) {
 620                         rc = ext4_fs_init_inode_table(ref);
 621                         if (rc != EOK) {
 622                                 ext4_block_set(fs->bdev, &ref->block);
 623                                 return rc;
 624                         }
 625
 626                         ext4_bg_set_flag(bg, EXT4_BLOCK_GROUP_ITABLE_ZEROED);
 627                 }
 628
 629                 ref->dirty = true;
 630         }
 631
 632         return EOK;
 633 }
 634
 635 int ext4_fs_put_block_group_ref(struct ext4_block_group_ref *ref)
 636 {
 637         /* Check if reference modified */
 638         if (ref->dirty) {
 639                 /* Compute new checksum of block group */
 640                 uint16_t cs;
 641                 cs = ext4_fs_bg_checksum(&ref->fs->sb, ref->index,
 642                                          ref->block_group);
 643                 ref->block_group->checksum = to_le16(cs);
 644
 645                 /* Mark block dirty for writing changes to physical device */
 646                 ext4_trans_set_block_dirty(ref->block.buf);
 647         }
 648
 649         /* Put back block, that contains block group descriptor */
 650         return ext4_block_set(ref->fs->bdev, &ref->block);
 651 }
 652
 653 #if CONFIG_META_CSUM_ENABLE
 654 static uint32_t ext4_fs_inode_checksum(struct ext4_inode_ref *inode_ref)
 655 {
 656         uint32_t checksum = 0;
 657         struct ext4_sblock *sb = &inode_ref->fs->sb;
 658         uint16_t inode_size = ext4_get16(sb, inode_size);
 659
 660         if (ext4_sb_feature_ro_com(sb, EXT4_FRO_COM_METADATA_CSUM)) {
 661                 uint32_t orig_checksum;
 662
 663                 uint32_t ino_index = to_le32(inode_ref->index);
 664                 uint32_t ino_gen =
 665                         to_le32(ext4_inode_get_generation(inode_ref->inode));
 666
 667                 /* Preparation: temporarily set bg checksum to 0 */
 668                 orig_checksum = ext4_inode_get_csum(sb, inode_ref->inode);
 669                 ext4_inode_set_csum(sb, inode_ref->inode, 0);
 670
 671                 /* First calculate crc32 checksum against fs uuid */
 672                 checksum = ext4_crc32c(EXT4_CRC32_INIT, sb->uuid,
 673                                        sizeof(sb->uuid));
 674                 /* Then calculate crc32 checksum against inode number
 675                  * and inode generation */
 676                 checksum = ext4_crc32c(checksum, &ino_index, sizeof(ino_index));
 677                 checksum = ext4_crc32c(checksum, &ino_gen, sizeof(ino_gen));
 678                 /* Finally calculate crc32 checksum against
 679                  * the entire inode */
 680                 checksum = ext4_crc32c(checksum, inode_ref->inode, inode_size);
 681                 ext4_inode_set_csum(sb, inode_ref->inode, orig_checksum);
 682
 683                 /* If inode size is not large enough to hold the
 684                  * upper 16bit of the checksum */
 685                 if (inode_size == EXT4_GOOD_OLD_INODE_SIZE)
 686                         checksum &= 0xFFFF;
 687
 688         }
 689         return checksum;
 690 }
 691 #else
 692 #define ext4_fs_inode_checksum(...) 0
 693 #endif
 694
 695 static void ext4_fs_set_inode_checksum(struct ext4_inode_ref *inode_ref)
 696 {
 697         struct ext4_sblock *sb = &inode_ref->fs->sb;
 698         if (!ext4_sb_feature_ro_com(sb, EXT4_FRO_COM_METADATA_CSUM))
 699                 return;
 700
 701         uint32_t csum = ext4_fs_inode_checksum(inode_ref);
 702         ext4_inode_set_csum(sb, inode_ref->inode, csum);
 703 }
 704
 705 #if CONFIG_META_CSUM_ENABLE
 706 static bool ext4_fs_verify_inode_csum(struct ext4_inode_ref *inode_ref)
 707 {
 708         struct ext4_sblock *sb = &inode_ref->fs->sb;
 709         if (!ext4_sb_feature_ro_com(sb, EXT4_FRO_COM_METADATA_CSUM))
 710                 return true;
 711
 712         return ext4_inode_get_csum(sb, inode_ref->inode) ==
 713                 ext4_fs_inode_checksum(inode_ref);
 714 }
 715 #else
 716 #define ext4_fs_verify_inode_csum(...) true
 717 #endif
 718
 719 static int
 720 __ext4_fs_get_inode_ref(struct ext4_fs *fs, uint32_t index,
 721                         struct ext4_inode_ref *ref,
 722                         bool initialized)
 723 {
 724         /* Compute number of i-nodes, that fits in one data block */
 725         uint32_t inodes_per_group = ext4_get32(&fs->sb, inodes_per_group);
 726
 727         /*
 728          * Inode numbers are 1-based, but it is simpler to work with 0-based
 729          * when computing indices
 730          */
 731         index -= 1;
 732         uint32_t block_group = index / inodes_per_group;
 733         uint32_t offset_in_group = index % inodes_per_group;
 734
 735         /* Load block group, where i-node is located */
 736         struct ext4_block_group_ref bg_ref;
 737
 738         int rc = ext4_fs_get_block_group_ref(fs, block_group, &bg_ref);
 739         if (rc != EOK) {
 740                 return rc;
 741         }
 742
 743         /* Load block address, where i-node table is located */
 744         ext4_fsblk_t inode_table_start =
 745             ext4_bg_get_inode_table_first_block(bg_ref.block_group, &fs->sb);
 746
 747         /* Put back block group reference (not needed more) */
 748         rc = ext4_fs_put_block_group_ref(&bg_ref);
 749         if (rc != EOK) {
 750                 return rc;
 751         }
 752
 753         /* Compute position of i-node in the block group */
 754         uint16_t inode_size = ext4_get16(&fs->sb, inode_size);
 755         uint32_t block_size = ext4_sb_get_block_size(&fs->sb);
 756         uint32_t byte_offset_in_group = offset_in_group * inode_size;
 757
 758         /* Compute block address */
 759         ext4_fsblk_t block_id =
 760             inode_table_start + (byte_offset_in_group / block_size);
 761
 762         rc = ext4_trans_block_get(fs->bdev, &ref->block, block_id);
 763         if (rc != EOK) {
 764                 return rc;
 765         }
 766
 767         /* Compute position of i-node in the data block */
 768         uint32_t offset_in_block = byte_offset_in_group % block_size;
 769         ref->inode = (struct ext4_inode *)(ref->block.data + offset_in_block);
 770
 771         /* We need to store the original value of index in the reference */
 772         ref->index = index + 1;
 773         ref->fs = fs;
 774         ref->dirty = false;
 775
 776         if (initialized && !ext4_fs_verify_inode_csum(ref)) {
 777                 ext4_dbg(DEBUG_FS,
 778                         DBG_WARN "Inode checksum failed."
 779                         "Inode: %" PRIu32"\n",
 780                         ref->index);
 781         }
 782
 783         return EOK;
 784 }
 785
 786 int ext4_fs_get_inode_ref(struct ext4_fs *fs, uint32_t index,
 787                           struct ext4_inode_ref *ref)
 788 {
 789         return __ext4_fs_get_inode_ref(fs, index, ref, true);
 790 }
 791
 792 int ext4_fs_put_inode_ref(struct ext4_inode_ref *ref)
 793 {
 794         /* Check if reference modified */
 795         if (ref->dirty) {
 796                 /* Mark block dirty for writing changes to physical device */
 797                 ext4_fs_set_inode_checksum(ref);
 798                 ext4_trans_set_block_dirty(ref->block.buf);
 799         }
 800
 801         /* Put back block, that contains i-node */
 802         return ext4_block_set(ref->fs->bdev, &ref->block);
 803 }
 804
 805 void ext4_fs_inode_blocks_init(struct ext4_fs *fs,
 806                                struct ext4_inode_ref *inode_ref)
 807 {
 808         int i;
 809         struct ext4_inode *inode = inode_ref->inode;
 810
 811         for (i = 0; i < EXT4_INODE_BLOCKS; i++)
 812                 inode->blocks[i] = 0;
 813
 814         (void)fs;
 815 #if CONFIG_EXTENT_ENABLE
 816         /* Initialize extents if needed */
 817         if (ext4_sb_feature_incom(&fs->sb, EXT4_FINCOM_EXTENTS)) {
 818                 ext4_inode_set_flag(inode, EXT4_INODE_FLAG_EXTENTS);
 819
 820                 /* Initialize extent root header */
 821                 ext4_extent_tree_init(inode_ref);
 822         }
 823 #endif
 824 }
 825
 826 uint32_t ext4_fs_correspond_inode_mode(int filetype)
 827 {
 828         switch (filetype) {
 829         case EXT4_DE_DIR:
 830                 return EXT4_INODE_MODE_DIRECTORY;
 831         case EXT4_DE_REG_FILE:
 832                 return EXT4_INODE_MODE_FILE;
 833         case EXT4_DE_SYMLINK:
 834                 return EXT4_INODE_MODE_SOFTLINK;
 835         case EXT4_DE_CHRDEV:
 836                 return EXT4_INODE_MODE_CHARDEV;
 837         case EXT4_DE_BLKDEV:
 838                 return EXT4_INODE_MODE_BLOCKDEV;
 839         case EXT4_DE_FIFO:
 840                 return EXT4_INODE_MODE_FIFO;
 841         case EXT4_DE_SOCK:
 842                 return EXT4_INODE_MODE_SOCKET;
 843         }
 844         /* FIXME: unsupported filetype */
 845         return EXT4_INODE_MODE_FILE;
 846 }
 847
 848 int ext4_fs_alloc_inode(struct ext4_fs *fs, struct ext4_inode_ref *inode_ref,
 849                         int filetype)
 850 {
 851         /* Check if newly allocated i-node will be a directory */
 852         bool is_dir;
 853         uint32_t type;
 854         uint16_t inode_size = ext4_get16(&fs->sb, inode_size);
 855
 856         is_dir = (filetype == EXT4_DE_DIR);
 857
 858         /* Allocate inode by allocation algorithm */
 859         uint32_t index;
 860         int rc = ext4_ialloc_alloc_inode(fs, &index, is_dir);
 861         if (rc != EOK)
 862                 return rc;
 863
 864         /* Load i-node from on-disk i-node table */
 865         rc = __ext4_fs_get_inode_ref(fs, index, inode_ref, false);
 866         if (rc != EOK) {
 867                 ext4_ialloc_free_inode(fs, index, is_dir);
 868                 return rc;
 869         }
 870
 871         /* Initialize i-node */
 872         struct ext4_inode *inode = inode_ref->inode;
 873
 874         memset(inode, 0, inode_size);
 875
 876         uint32_t mode;
 877         if (is_dir) {
 878                 /*
 879                  * Default directory permissions to be compatible with other
 880                  * systems
 881                  * 0777 (octal) == rwxrwxrwx
 882                  */
 883
 884                 mode = 0777;
 885                 mode |= EXT4_INODE_MODE_DIRECTORY;
 886         } else if (filetype == EXT4_DE_SYMLINK) {
 887                 /*
 888                  * Default symbolic link permissions to be compatible with other systems
 889                  * 0777 (octal) == rwxrwxrwx
 890                  */
 891
 892                 mode = 0777;
 893                 mode |= EXT4_INODE_MODE_SOFTLINK;
 894         } else {
 895                 /*
 896                  * Default file permissions to be compatible with other systems
 897                  * 0666 (octal) == rw-rw-rw-
 898                  */
 899
 900                 mode = 0666;
 901                 mode |= ext4_fs_correspond_inode_mode(filetype);
 902         }
 903         ext4_inode_set_mode(&fs->sb, inode, mode);
 904
 905         ext4_inode_set_links_cnt(inode, 0);
 906         ext4_inode_set_uid(inode, 0);
 907         ext4_inode_set_gid(inode, 0);
 908         ext4_inode_set_size(inode, 0);
 909         ext4_inode_set_access_time(inode, 0);
 910         ext4_inode_set_change_inode_time(inode, 0);
 911         ext4_inode_set_modif_time(inode, 0);
 912         ext4_inode_set_del_time(inode, 0);
 913         ext4_inode_set_blocks_count(&fs->sb, inode, 0);
 914         ext4_inode_set_flags(inode, 0);
 915         ext4_inode_set_generation(inode, 0);
 916         if (inode_size > EXT4_GOOD_OLD_INODE_SIZE) {
 917                 uint16_t off = offsetof(struct ext4_inode, extra_isize);
 918                 uint16_t size = sizeof(struct ext4_inode) - off;
 919                 ext4_inode_set_extra_isize(&fs->sb, inode, size);
 920         }
 921
 922         /* Reset blocks array. For inode which is not directory or file, just
 923          * fill in blocks with 0 */
 924         type = ext4_inode_type(&fs->sb, inode_ref->inode);
 925         if (type == EXT4_INODE_MODE_CHARDEV ||
 926             type == EXT4_INODE_MODE_BLOCKDEV ||
 927             type == EXT4_INODE_MODE_SOCKET ||
 928             type == EXT4_INODE_MODE_SOFTLINK) {
 929                 for (int i = 0; i < EXT4_INODE_BLOCKS; i++)
 930                         inode->blocks[i] = 0;
 931
 932         } else {
 933                 ext4_fs_inode_blocks_init(fs, inode_ref);
 934         }
 935
 936         inode_ref->dirty = true;
 937
 938         return EOK;
 939 }
 940
 941 int ext4_fs_free_inode(struct ext4_inode_ref *inode_ref)
 942 {
 943         struct ext4_fs *fs = inode_ref->fs;
 944         uint32_t offset;
 945         uint32_t suboff;
 946         int rc;
 947 #if CONFIG_EXTENT_ENABLE
 948         /* For extents must be data block destroyed by other way */
 949         if ((ext4_sb_feature_incom(&fs->sb, EXT4_FINCOM_EXTENTS)) &&
 950             (ext4_inode_has_flag(inode_ref->inode, EXT4_INODE_FLAG_EXTENTS))) {
 951                 /* Data structures are released during truncate operation... */
 952                 goto finish;
 953         }
 954 #endif
 955         /* Release all indirect (no data) blocks */
 956
 957         /* 1) Single indirect */
 958         ext4_fsblk_t fblock = ext4_inode_get_indirect_block(inode_ref->inode, 0);
 959         if (fblock != 0) {
 960                 int rc = ext4_balloc_free_block(inode_ref, fblock);
 961                 if (rc != EOK)
 962                         return rc;
 963
 964                 ext4_inode_set_indirect_block(inode_ref->inode, 0, 0);
 965         }
 966
 967         uint32_t block_size = ext4_sb_get_block_size(&fs->sb);
 968         uint32_t count = block_size / sizeof(uint32_t);
 969
 970         struct ext4_block block;
 971
 972         /* 2) Double indirect */
 973         fblock = ext4_inode_get_indirect_block(inode_ref->inode, 1);
 974         if (fblock != 0) {
 975                 int rc = ext4_trans_block_get(fs->bdev, &block, fblock);
 976                 if (rc != EOK)
 977                         return rc;
 978
 979                 ext4_fsblk_t ind_block;
 980                 for (offset = 0; offset < count; ++offset) {
 981                         ind_block = to_le32(((uint32_t *)block.data)[offset]);
 982
 983                         if (ind_block == 0)
 984                                 continue;
 985                         rc = ext4_balloc_free_block(inode_ref, ind_block);
 986                         if (rc != EOK) {
 987                                 ext4_block_set(fs->bdev, &block);
 988                                 return rc;
 989                         }
 990
 991                 }
 992
 993                 ext4_block_set(fs->bdev, &block);
 994                 rc = ext4_balloc_free_block(inode_ref, fblock);
 995                 if (rc != EOK)
 996                         return rc;
 997
 998                 ext4_inode_set_indirect_block(inode_ref->inode, 1, 0);
 999         }
1000
1001         /* 3) Tripple indirect */
1002         struct ext4_block subblock;
1003         fblock = ext4_inode_get_indirect_block(inode_ref->inode, 2);
1004         if (fblock == 0)
1005                 goto finish;
1006         rc = ext4_trans_block_get(fs->bdev, &block, fblock);
1007         if (rc != EOK)
1008                 return rc;
1009
1010         ext4_fsblk_t ind_block;
1011         for (offset = 0; offset < count; ++offset) {
1012                 ind_block = to_le32(((uint32_t *)block.data)[offset]);
1013
1014                 if (ind_block == 0)
1015                         continue;
1016                 rc = ext4_trans_block_get(fs->bdev, &subblock,
1017                                 ind_block);
1018                 if (rc != EOK) {
1019                         ext4_block_set(fs->bdev, &block);
1020                         return rc;
1021                 }
1022
1023                 ext4_fsblk_t ind_subblk;
1024                 for (suboff = 0; suboff < count; ++suboff) {
1025                         ind_subblk = to_le32(((uint32_t *)subblock.data)[suboff]);
1026
1027                         if (ind_subblk == 0)
1028                                 continue;
1029                         rc = ext4_balloc_free_block(inode_ref, ind_subblk);
1030                         if (rc != EOK) {
1031                                 ext4_block_set(fs->bdev, &subblock);
1032                                 ext4_block_set(fs->bdev, &block);
1033                                 return rc;
1034                         }
1035
1036                 }
1037
1038                 ext4_block_set(fs->bdev, &subblock);
1039
1040                 rc = ext4_balloc_free_block(inode_ref,
1041                                 ind_block);
1042                 if (rc != EOK) {
1043                         ext4_block_set(fs->bdev, &block);
1044                         return rc;
1045                 }
1046
1047         }
1048
1049         ext4_block_set(fs->bdev, &block);
1050         rc = ext4_balloc_free_block(inode_ref, fblock);
1051         if (rc != EOK)
1052                 return rc;
1053
1054         ext4_inode_set_indirect_block(inode_ref->inode, 2, 0);
1055 finish:
1056         /* Mark inode dirty for writing to the physical device */
1057         inode_ref->dirty = true;
1058
1059         /* Free block with extended attributes if present */
1060         ext4_fsblk_t xattr_block =
1061             ext4_inode_get_file_acl(inode_ref->inode, &fs->sb);
1062         if (xattr_block) {
1063                 int rc = ext4_balloc_free_block(inode_ref, xattr_block);
1064                 if (rc != EOK)
1065                         return rc;
1066
1067                 ext4_inode_set_file_acl(inode_ref->inode, &fs->sb, 0);
1068         }
1069
1070         /* Free inode by allocator */
1071         if (ext4_inode_is_type(&fs->sb, inode_ref->inode,
1072                                EXT4_INODE_MODE_DIRECTORY))
1073                 rc = ext4_ialloc_free_inode(fs, inode_ref->index, true);
1074         else
1075                 rc = ext4_ialloc_free_inode(fs, inode_ref->index, false);
1076
1077         return rc;
1078 }
1079
1080
1081 /**@brief Release data block from i-node
1082  * @param inode_ref I-node to release block from
1083  * @param iblock    Logical block to be released
1084  * @return Error code
1085  */
1086 static int ext4_fs_release_inode_block(struct ext4_inode_ref *inode_ref,
1087                                 ext4_lblk_t iblock)
1088 {
1089         ext4_fsblk_t fblock;
1090
1091         struct ext4_fs *fs = inode_ref->fs;
1092
1093         /* Extents are handled otherwise = there is not support in this function
1094          */
1095         ext4_assert(!(
1096             ext4_sb_feature_incom(&fs->sb, EXT4_FINCOM_EXTENTS) &&
1097             (ext4_inode_has_flag(inode_ref->inode, EXT4_INODE_FLAG_EXTENTS))));
1098
1099         struct ext4_inode *inode = inode_ref->inode;
1100
1101         /* Handle simple case when we are dealing with direct reference */
1102         if (iblock < EXT4_INODE_DIRECT_BLOCK_COUNT) {
1103                 fblock = ext4_inode_get_direct_block(inode, iblock);
1104
1105                 /* Sparse file */
1106                 if (fblock == 0)
1107                         return EOK;
1108
1109                 ext4_inode_set_direct_block(inode, iblock, 0);
1110                 return ext4_balloc_free_block(inode_ref, fblock);
1111         }
1112
1113         /* Determine the indirection level needed to get the desired block */
1114         unsigned int level = 0;
1115         unsigned int i;
1116         for (i = 1; i < 4; i++) {
1117                 if (iblock < fs->inode_block_limits[i]) {
1118                         level = i;
1119                         break;
1120                 }
1121         }
1122
1123         if (level == 0)
1124                 return EIO;
1125
1126         /* Compute offsets for the topmost level */
1127         uint32_t block_offset_in_level =
1128                 (uint32_t)(iblock - fs->inode_block_limits[level - 1]);
1129         ext4_fsblk_t current_block =
1130             ext4_inode_get_indirect_block(inode, level - 1);
1131         uint32_t offset_in_block =
1132             (uint32_t)(block_offset_in_level / fs->inode_blocks_per_level[level - 1]);
1133
1134         /*
1135          * Navigate through other levels, until we find the block number
1136          * or find null reference meaning we are dealing with sparse file
1137          */
1138         struct ext4_block block;
1139
1140         while (level > 0) {
1141
1142                 /* Sparse check */
1143                 if (current_block == 0)
1144                         return EOK;
1145
1146                 int rc = ext4_trans_block_get(fs->bdev, &block, current_block);
1147                 if (rc != EOK)
1148                         return rc;
1149
1150                 current_block =
1151                     to_le32(((uint32_t *)block.data)[offset_in_block]);
1152
1153                 /* Set zero if physical data block address found */
1154                 if (level == 1) {
1155                         ((uint32_t *)block.data)[offset_in_block] = to_le32(0);
1156                         ext4_trans_set_block_dirty(block.buf);
1157                 }
1158
1159                 rc = ext4_block_set(fs->bdev, &block);
1160                 if (rc != EOK)
1161                         return rc;
1162
1163                 level--;
1164
1165                 /*
1166                  * If we are on the last level, break here as
1167                  * there is no next level to visit
1168                  */
1169                 if (level == 0)
1170                         break;
1171
1172                 /* Visit the next level */
1173                 block_offset_in_level %= fs->inode_blocks_per_level[level];
1174                 offset_in_block = (uint32_t)(block_offset_in_level /
1175                                   fs->inode_blocks_per_level[level - 1]);
1176         }
1177
1178         fblock = current_block;
1179         if (fblock == 0)
1180                 return EOK;
1181
1182         /* Physical block is not referenced, it can be released */
1183         return ext4_balloc_free_block(inode_ref, fblock);
1184 }
1185
1186 int ext4_fs_truncate_inode(struct ext4_inode_ref *inode_ref, uint64_t new_size)
1187 {
1188         struct ext4_sblock *sb = &inode_ref->fs->sb;
1189         uint32_t i;
1190         int r;
1191         bool v;
1192
1193         /* Check flags, if i-node can be truncated */
1194         if (!ext4_inode_can_truncate(sb, inode_ref->inode))
1195                 return EINVAL;
1196
1197         /* If sizes are equal, nothing has to be done. */
1198         uint64_t old_size = ext4_inode_get_size(sb, inode_ref->inode);
1199         if (old_size == new_size)
1200                 return EOK;
1201
1202         /* It's not supported to make the larger file by truncate operation */
1203         if (old_size < new_size)
1204                 return EINVAL;
1205
1206         /* For symbolic link which is small enough */
1207         v = ext4_inode_is_type(sb, inode_ref->inode, EXT4_INODE_MODE_SOFTLINK);
1208         if (v && old_size < sizeof(inode_ref->inode->blocks) &&
1209             !ext4_inode_get_blocks_count(sb, inode_ref->inode)) {
1210                 char *content = (char *)inode_ref->inode->blocks + new_size;
1211                 memset(content, 0,
1212                        sizeof(inode_ref->inode->blocks) - (uint32_t)new_size);
1213                 ext4_inode_set_size(inode_ref->inode, new_size);
1214                 inode_ref->dirty = true;
1215
1216                 return EOK;
1217         }
1218
1219         i = ext4_inode_type(sb, inode_ref->inode);
1220         if (i == EXT4_INODE_MODE_CHARDEV ||
1221             i == EXT4_INODE_MODE_BLOCKDEV ||
1222             i == EXT4_INODE_MODE_SOCKET) {
1223                 inode_ref->inode->blocks[0] = 0;
1224                 inode_ref->inode->blocks[1] = 0;
1225
1226                 inode_ref->dirty = true;
1227                 return EOK;
1228         }
1229
1230         /* Compute how many blocks will be released */
1231         uint32_t block_size = ext4_sb_get_block_size(sb);
1232         uint32_t new_blocks_cnt = (uint32_t)((new_size + block_size - 1) / block_size);
1233         uint32_t old_blocks_cnt = (uint32_t)((old_size + block_size - 1) / block_size);
1234         uint32_t diff_blocks_cnt = old_blocks_cnt - new_blocks_cnt;
1235 #if CONFIG_EXTENT_ENABLE
1236         if ((ext4_sb_feature_incom(sb, EXT4_FINCOM_EXTENTS)) &&
1237             (ext4_inode_has_flag(inode_ref->inode, EXT4_INODE_FLAG_EXTENTS))) {
1238
1239                 /* Extents require special operation */
1240                 if (diff_blocks_cnt) {
1241                         r = ext4_extent_remove_space(inode_ref, new_blocks_cnt,
1242                                                      EXT_MAX_BLOCKS);
1243                         if (r != EOK)
1244                                 return r;
1245
1246                 }
1247         } else
1248 #endif
1249         {
1250                 /* Release data blocks from the end of file */
1251
1252                 /* Starting from 1 because of logical blocks are numbered from 0
1253                  */
1254                 for (i = 0; i < diff_blocks_cnt; ++i) {
1255                         r = ext4_fs_release_inode_block(inode_ref,
1256                                                         new_blocks_cnt + i);
1257                         if (r != EOK)
1258                                 return r;
1259                 }
1260         }
1261
1262         /* Update i-node */
1263         ext4_inode_set_size(inode_ref->inode, new_size);
1264         inode_ref->dirty = true;
1265
1266         return EOK;
1267 }
1268
1269 /**@brief Compute 'goal' for inode index
1270  * @param inode_ref Reference to inode, to allocate block for
1271  * @return goal
1272  */
1273 ext4_fsblk_t ext4_fs_inode_to_goal_block(struct ext4_inode_ref *inode_ref)
1274 {
1275         uint32_t grp_inodes = ext4_get32(&inode_ref->fs->sb, inodes_per_group);
1276         return (inode_ref->index - 1) / grp_inodes;
1277 }
1278
1279 /**@brief Compute 'goal' for allocation algorithm (For blockmap).
1280  * @param inode_ref Reference to inode, to allocate block for
1281  * @param goal
1282  * @return error code
1283  */
1284 int ext4_fs_indirect_find_goal(struct ext4_inode_ref *inode_ref,
1285                                ext4_fsblk_t *goal)
1286 {
1287         int r;
1288         struct ext4_sblock *sb = &inode_ref->fs->sb;
1289         *goal = 0;
1290
1291         uint64_t inode_size = ext4_inode_get_size(sb, inode_ref->inode);
1292         uint32_t block_size = ext4_sb_get_block_size(sb);
1293         uint32_t iblock_cnt = (uint32_t)(inode_size / block_size);
1294
1295         if (inode_size % block_size != 0)
1296                 iblock_cnt++;
1297
1298         /* If inode has some blocks, get last block address + 1 */
1299         if (iblock_cnt > 0) {
1300                 r = ext4_fs_get_inode_dblk_idx(inode_ref, iblock_cnt - 1,
1301                                                goal, false);
1302                 if (r != EOK)
1303                         return r;
1304
1305                 if (*goal != 0) {
1306                         (*goal)++;
1307                         return r;
1308                 }
1309
1310                 /* If goal == 0, sparse file -> continue */
1311         }
1312
1313         /* Identify block group of inode */
1314
1315         uint32_t inodes_per_bg = ext4_get32(sb, inodes_per_group);
1316         uint32_t block_group = (inode_ref->index - 1) / inodes_per_bg;
1317         block_size = ext4_sb_get_block_size(sb);
1318
1319         /* Load block group reference */
1320         struct ext4_block_group_ref bg_ref;
1321         r = ext4_fs_get_block_group_ref(inode_ref->fs, block_group, &bg_ref);
1322         if (r != EOK)
1323                 return r;
1324
1325         struct ext4_bgroup *bg = bg_ref.block_group;
1326
1327         /* Compute indexes */
1328         uint32_t bg_count = ext4_block_group_cnt(sb);
1329         ext4_fsblk_t itab_first_block = ext4_bg_get_inode_table_first_block(bg, sb);
1330         uint16_t itab_item_size = ext4_get16(sb, inode_size);
1331         uint32_t itab_bytes;
1332
1333         /* Check for last block group */
1334         if (block_group < bg_count - 1) {
1335                 itab_bytes = inodes_per_bg * itab_item_size;
1336         } else {
1337                 /* Last block group could be smaller */
1338                 uint32_t inodes_cnt = ext4_get32(sb, inodes_count);
1339
1340                 itab_bytes = (inodes_cnt - ((bg_count - 1) * inodes_per_bg));
1341                 itab_bytes *= itab_item_size;
1342         }
1343
1344         ext4_fsblk_t inode_table_blocks = itab_bytes / block_size;
1345
1346         if (itab_bytes % block_size)
1347                 inode_table_blocks++;
1348
1349         *goal = itab_first_block + inode_table_blocks;
1350
1351         return ext4_fs_put_block_group_ref(&bg_ref);
1352 }
1353
1354 static int ext4_fs_get_inode_dblk_idx_internal(struct ext4_inode_ref *inode_ref,
1355                                        ext4_lblk_t iblock, ext4_fsblk_t *fblock,
1356                                        bool extent_create,
1357                                        bool support_unwritten __unused)
1358 {
1359         struct ext4_fs *fs = inode_ref->fs;
1360
1361         /* For empty file is situation simple */
1362         if (ext4_inode_get_size(&fs->sb, inode_ref->inode) == 0) {
1363                 *fblock = 0;
1364                 return EOK;
1365         }
1366
1367         ext4_fsblk_t current_block;
1368
1369         (void)extent_create;
1370 #if CONFIG_EXTENT_ENABLE
1371         /* Handle i-node using extents */
1372         if ((ext4_sb_feature_incom(&fs->sb, EXT4_FINCOM_EXTENTS)) &&
1373             (ext4_inode_has_flag(inode_ref->inode, EXT4_INODE_FLAG_EXTENTS))) {
1374
1375                 ext4_fsblk_t current_fsblk;
1376                 int rc = ext4_extent_get_blocks(inode_ref, iblock, 1,
1377                                 &current_fsblk, extent_create, NULL);
1378                 if (rc != EOK)
1379                         return rc;
1380
1381                 current_block = current_fsblk;
1382                 *fblock = current_block;
1383
1384                 ext4_assert(*fblock || support_unwritten);
1385                 return EOK;
1386         }
1387 #endif
1388
1389         struct ext4_inode *inode = inode_ref->inode;
1390
1391         /* Direct block are read directly from array in i-node structure */
1392         if (iblock < EXT4_INODE_DIRECT_BLOCK_COUNT) {
1393                 current_block =
1394                     ext4_inode_get_direct_block(inode, (uint32_t)iblock);
1395                 *fblock = current_block;
1396                 return EOK;
1397         }
1398
1399         /* Determine indirection level of the target block */
1400         unsigned int l = 0;
1401         unsigned int i;
1402         for (i = 1; i < 4; i++) {
1403                 if (iblock < fs->inode_block_limits[i]) {
1404                         l = i;
1405                         break;
1406                 }
1407         }
1408
1409         if (l == 0)
1410                 return EIO;
1411
1412         /* Compute offsets for the topmost level */
1413         uint32_t blk_off_in_lvl = (uint32_t)(iblock - fs->inode_block_limits[l - 1]);
1414         current_block = ext4_inode_get_indirect_block(inode, l - 1);
1415         uint32_t off_in_blk = (uint32_t)(blk_off_in_lvl / fs->inode_blocks_per_level[l - 1]);
1416
1417         /* Sparse file */
1418         if (current_block == 0) {
1419                 *fblock = 0;
1420                 return EOK;
1421         }
1422
1423         struct ext4_block block;
1424
1425         /*
1426          * Navigate through other levels, until we find the block number
1427          * or find null reference meaning we are dealing with sparse file
1428          */
1429         while (l > 0) {
1430                 /* Load indirect block */
1431                 int rc = ext4_trans_block_get(fs->bdev, &block, current_block);
1432                 if (rc != EOK)
1433                         return rc;
1434
1435                 /* Read block address from indirect block */
1436                 current_block =
1437                     to_le32(((uint32_t *)block.data)[off_in_blk]);
1438
1439                 /* Put back indirect block untouched */
1440                 rc = ext4_block_set(fs->bdev, &block);
1441                 if (rc != EOK)
1442                         return rc;
1443
1444                 /* Check for sparse file */
1445                 if (current_block == 0) {
1446                         *fblock = 0;
1447                         return EOK;
1448                 }
1449
1450                 /* Jump to the next level */
1451                 l--;
1452
1453                 /* Termination condition - we have address of data block loaded
1454                  */
1455                 if (l == 0)
1456                         break;
1457
1458                 /* Visit the next level */
1459                 blk_off_in_lvl %= fs->inode_blocks_per_level[l];
1460                 off_in_blk = (uint32_t)(blk_off_in_lvl / fs->inode_blocks_per_level[l - 1]);
1461         }
1462
1463         *fblock = current_block;
1464
1465         return EOK;
1466 }
1467
1468
1469 int ext4_fs_get_inode_dblk_idx(struct ext4_inode_ref *inode_ref,
1470                                ext4_lblk_t iblock, ext4_fsblk_t *fblock,
1471                                bool support_unwritten)
1472 {
1473         return ext4_fs_get_inode_dblk_idx_internal(inode_ref, iblock, fblock,
1474                                                    false, support_unwritten);
1475 }
1476
1477 int ext4_fs_init_inode_dblk_idx(struct ext4_inode_ref *inode_ref,
1478                                 ext4_lblk_t iblock, ext4_fsblk_t *fblock)
1479 {
1480         return ext4_fs_get_inode_dblk_idx_internal(inode_ref, iblock, fblock,
1481                                                    true, true);
1482 }
1483
1484 static int ext4_fs_set_inode_data_block_index(struct ext4_inode_ref *inode_ref,
1485                                        ext4_lblk_t iblock, ext4_fsblk_t fblock)
1486 {
1487         struct ext4_fs *fs = inode_ref->fs;
1488
1489 #if CONFIG_EXTENT_ENABLE
1490         /* Handle inode using extents */
1491         if ((ext4_sb_feature_incom(&fs->sb, EXT4_FINCOM_EXTENTS)) &&
1492             (ext4_inode_has_flag(inode_ref->inode, EXT4_INODE_FLAG_EXTENTS))) {
1493                 /* Not reachable */
1494                 return ENOTSUP;
1495         }
1496 #endif
1497
1498         /* Handle simple case when we are dealing with direct reference */
1499         if (iblock < EXT4_INODE_DIRECT_BLOCK_COUNT) {
1500                 ext4_inode_set_direct_block(inode_ref->inode, (uint32_t)iblock,
1501                                             (uint32_t)fblock);
1502                 inode_ref->dirty = true;
1503
1504                 return EOK;
1505         }
1506
1507         /* Determine the indirection level needed to get the desired block */
1508         unsigned int l = 0;
1509         unsigned int i;
1510         for (i = 1; i < 4; i++) {
1511                 if (iblock < fs->inode_block_limits[i]) {
1512                         l = i;
1513                         break;
1514                 }
1515         }
1516
1517         if (l == 0)
1518                 return EIO;
1519
1520         uint32_t block_size = ext4_sb_get_block_size(&fs->sb);
1521
1522         /* Compute offsets for the topmost level */
1523         uint32_t blk_off_in_lvl = (uint32_t)(iblock - fs->inode_block_limits[l - 1]);
1524         ext4_fsblk_t current_block =
1525                         ext4_inode_get_indirect_block(inode_ref->inode, l - 1);
1526         uint32_t off_in_blk = (uint32_t)(blk_off_in_lvl / fs->inode_blocks_per_level[l - 1]);
1527
1528         ext4_fsblk_t new_blk;
1529
1530         struct ext4_block block;
1531         struct ext4_block new_block;
1532
1533         /* Is needed to allocate indirect block on the i-node level */
1534         if (current_block == 0) {
1535                 /* Allocate new indirect block */
1536                 ext4_fsblk_t goal;
1537                 int rc = ext4_fs_indirect_find_goal(inode_ref, &goal);
1538                 if (rc != EOK)
1539                         return rc;
1540
1541                 rc = ext4_balloc_alloc_block(inode_ref, goal, &new_blk);
1542                 if (rc != EOK)
1543                         return rc;
1544
1545                 /* Update i-node */
1546                 ext4_inode_set_indirect_block(inode_ref->inode, l - 1,
1547                                 (uint32_t)new_blk);
1548                 inode_ref->dirty = true;
1549
1550                 /* Load newly allocated block */
1551                 rc = ext4_trans_block_get_noread(fs->bdev, &new_block, new_blk);
1552                 if (rc != EOK) {
1553                         ext4_balloc_free_block(inode_ref, new_blk);
1554                         return rc;
1555                 }
1556
1557                 /* Initialize new block */
1558                 memset(new_block.data, 0, block_size);
1559                 ext4_trans_set_block_dirty(new_block.buf);
1560
1561                 /* Put back the allocated block */
1562                 rc = ext4_block_set(fs->bdev, &new_block);
1563                 if (rc != EOK)
1564                         return rc;
1565
1566                 current_block = new_blk;
1567         }
1568
1569         /*
1570          * Navigate through other levels, until we find the block number
1571          * or find null reference meaning we are dealing with sparse file
1572          */
1573         while (l > 0) {
1574                 int rc = ext4_trans_block_get(fs->bdev, &block, current_block);
1575                 if (rc != EOK)
1576                         return rc;
1577
1578                 current_block = to_le32(((uint32_t *)block.data)[off_in_blk]);
1579                 if ((l > 1) && (current_block == 0)) {
1580                         ext4_fsblk_t goal;
1581                         rc = ext4_fs_indirect_find_goal(inode_ref, &goal);
1582                         if (rc != EOK) {
1583                                 ext4_block_set(fs->bdev, &block);
1584                                 return rc;
1585                         }
1586
1587                         /* Allocate new block */
1588                         rc =
1589                             ext4_balloc_alloc_block(inode_ref, goal, &new_blk);
1590                         if (rc != EOK) {
1591                                 ext4_block_set(fs->bdev, &block);
1592                                 return rc;
1593                         }
1594
1595                         /* Load newly allocated block */
1596                         rc = ext4_trans_block_get_noread(fs->bdev, &new_block,
1597                                             new_blk);
1598
1599                         if (rc != EOK) {
1600                                 ext4_block_set(fs->bdev, &block);
1601                                 return rc;
1602                         }
1603
1604                         /* Initialize allocated block */
1605                         memset(new_block.data, 0, block_size);
1606                         ext4_trans_set_block_dirty(new_block.buf);
1607
1608                         rc = ext4_block_set(fs->bdev, &new_block);
1609                         if (rc != EOK) {
1610                                 ext4_block_set(fs->bdev, &block);
1611                                 return rc;
1612                         }
1613
1614                         /* Write block address to the parent */
1615                         uint32_t * p = (uint32_t * )block.data;
1616                         p[off_in_blk] = to_le32((uint32_t)new_blk);
1617                         ext4_trans_set_block_dirty(block.buf);
1618                         current_block = new_blk;
1619                 }
1620
1621                 /* Will be finished, write the fblock address */
1622                 if (l == 1) {
1623                         uint32_t * p = (uint32_t * )block.data;
1624                         p[off_in_blk] = to_le32((uint32_t)fblock);
1625                         ext4_trans_set_block_dirty(block.buf);
1626                 }
1627
1628                 rc = ext4_block_set(fs->bdev, &block);
1629                 if (rc != EOK)
1630                         return rc;
1631
1632                 l--;
1633
1634                 /*
1635                  * If we are on the last level, break here as
1636                  * there is no next level to visit
1637                  */
1638                 if (l == 0)
1639                         break;
1640
1641                 /* Visit the next level */
1642                 blk_off_in_lvl %= fs->inode_blocks_per_level[l];
1643                 off_in_blk = (uint32_t)(blk_off_in_lvl / fs->inode_blocks_per_level[l - 1]);
1644         }
1645
1646         return EOK;
1647 }
1648
1649
1650 int ext4_fs_append_inode_dblk(struct ext4_inode_ref *inode_ref,
1651                               ext4_fsblk_t *fblock, ext4_lblk_t *iblock)
1652 {
1653 #if CONFIG_EXTENT_ENABLE
1654         /* Handle extents separately */
1655         if ((ext4_sb_feature_incom(&inode_ref->fs->sb, EXT4_FINCOM_EXTENTS)) &&
1656             (ext4_inode_has_flag(inode_ref->inode, EXT4_INODE_FLAG_EXTENTS))) {
1657                 int rc;
1658                 ext4_fsblk_t current_fsblk;
1659                 struct ext4_sblock *sb = &inode_ref->fs->sb;
1660                 uint64_t inode_size = ext4_inode_get_size(sb, inode_ref->inode);
1661                 uint32_t block_size = ext4_sb_get_block_size(sb);
1662                 *iblock = (uint32_t)((inode_size + block_size - 1) / block_size);
1663
1664                 rc = ext4_extent_get_blocks(inode_ref, *iblock, 1,
1665                                                 &current_fsblk, true, NULL);
1666                 if (rc != EOK)
1667                         return rc;
1668
1669                 *fblock = current_fsblk;
1670                 ext4_assert(*fblock);
1671
1672                 ext4_inode_set_size(inode_ref->inode, inode_size + block_size);
1673                 inode_ref->dirty = true;
1674
1675
1676                 return rc;
1677         }
1678 #endif
1679         struct ext4_sblock *sb = &inode_ref->fs->sb;
1680
1681         /* Compute next block index and allocate data block */
1682         uint64_t inode_size = ext4_inode_get_size(sb, inode_ref->inode);
1683         uint32_t block_size = ext4_sb_get_block_size(sb);
1684
1685         /* Align size i-node size */
1686         if ((inode_size % block_size) != 0)
1687                 inode_size += block_size - (inode_size % block_size);
1688
1689         /* Logical blocks are numbered from 0 */
1690         uint32_t new_block_idx = (uint32_t)(inode_size / block_size);
1691
1692         /* Allocate new physical block */
1693         ext4_fsblk_t goal, phys_block;
1694         int rc = ext4_fs_indirect_find_goal(inode_ref, &goal);
1695         if (rc != EOK)
1696                 return rc;
1697
1698         rc = ext4_balloc_alloc_block(inode_ref, goal, &phys_block);
1699         if (rc != EOK)
1700                 return rc;
1701
1702         /* Add physical block address to the i-node */
1703         rc = ext4_fs_set_inode_data_block_index(inode_ref, new_block_idx,
1704                                                 phys_block);
1705         if (rc != EOK) {
1706                 ext4_balloc_free_block(inode_ref, phys_block);
1707                 return rc;
1708         }
1709
1710         /* Update i-node */
1711         ext4_inode_set_size(inode_ref->inode, inode_size + block_size);
1712         inode_ref->dirty = true;
1713
1714         *fblock = phys_block;
1715         *iblock = new_block_idx;
1716
1717         return EOK;
1718 }
1719
1720 void ext4_fs_inode_links_count_inc(struct ext4_inode_ref *inode_ref)
1721 {
1722         uint16_t link;
1723         bool is_dx;
1724         link = ext4_inode_get_links_cnt(inode_ref->inode);
1725         link++;
1726         ext4_inode_set_links_cnt(inode_ref->inode, link);
1727
1728         is_dx = ext4_sb_feature_com(&inode_ref->fs->sb, EXT4_FCOM_DIR_INDEX) &&
1729                 ext4_inode_has_flag(inode_ref->inode, EXT4_INODE_FLAG_INDEX);
1730
1731         if (is_dx && link > 1) {
1732                 if (link >= EXT4_LINK_MAX || link == 2) {
1733                         ext4_inode_set_links_cnt(inode_ref->inode, 1);
1734
1735                         uint32_t v;
1736                         v = ext4_get32(&inode_ref->fs->sb, features_read_only);
1737                         v |= EXT4_FRO_COM_DIR_NLINK;
1738                         ext4_set32(&inode_ref->fs->sb, features_read_only, v);
1739                 }
1740         }
1741 }
1742
1743 void ext4_fs_inode_links_count_dec(struct ext4_inode_ref *inode_ref)
1744 {
1745         uint16_t links = ext4_inode_get_links_cnt(inode_ref->inode);
1746         if (!ext4_inode_is_type(&inode_ref->fs->sb, inode_ref->inode,
1747                                 EXT4_INODE_MODE_DIRECTORY)) {
1748                 if (links > 0)
1749                         ext4_inode_set_links_cnt(inode_ref->inode, links - 1);
1750                 return;
1751         }
1752
1753         if (links > 2)
1754                 ext4_inode_set_links_cnt(inode_ref->inode, links - 1);
1755 }
1756
1757 /**
1758  * @}
1759  */