ext4_utils/ext4_utils.c

   1 /*
   2  * Copyright (C) 2010 The Android Open Source Project
   3  *
   4  * Licensed under the Apache License, Version 2.0 (the "License");
   5  * you may not use this file except in compliance with the License.
   6  * You may obtain a copy of the License at
   7  *
   8  *      http://www.apache.org/licenses/LICENSE-2.0
   9  *
  10  * Unless required by applicable law or agreed to in writing, software
  11  * distributed under the License is distributed on an "AS IS" BASIS,
  12  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
  13  * See the License for the specific language governing permissions and
  14  * limitations under the License.
  15  */
  16
  17 #include "ext4_utils.h"
  18 #include "allocate.h"
  19 #include "indirect.h"
  20 #include "extent.h"
  21 #include "sha1.h"
  22
  23 #include <sparse/sparse.h>
  24 #ifdef REAL_UUID
  25 #include <uuid.h>
  26 #endif
  27
  28 #include <fcntl.h>
  29 #include <inttypes.h>
  30 #include <sys/stat.h>
  31 #include <sys/types.h>
  32 #include <stddef.h>
  33 #include <string.h>
  34
  35 #ifdef USE_MINGW
  36 #include <winsock2.h>
  37 #else
  38 #include <arpa/inet.h>
  39 #include <sys/ioctl.h>
  40 #endif
  41
  42 #if defined(__linux__)
  43 #include <linux/fs.h>
  44 #elif defined(__APPLE__) && defined(__MACH__)
  45 #include <sys/disk.h>
  46 #endif
  47
  48 int force = 0;
  49 struct fs_info info;
  50 struct fs_aux_info aux_info;
  51 struct sparse_file *ext4_sparse_file;
  52
  53 jmp_buf setjmp_env;
  54
  55 /* Definition from RFC-4122 */
  56 struct uuid {
  57     u32 time_low;
  58     u16 time_mid;
  59     u16 time_hi_and_version;
  60     u8 clk_seq_hi_res;
  61     u8 clk_seq_low;
  62     u16 node0_1;
  63     u32 node2_5;
  64 };
  65
  66 static void sha1_hash(const char *namespace, const char *name,
  67     unsigned char sha1[SHA1_DIGEST_LENGTH])
  68 {
  69     SHA1_CTX ctx;
  70     SHA1Init(&ctx);
  71     SHA1Update(&ctx, (const u8*)namespace, strlen(namespace));
  72     SHA1Update(&ctx, (const u8*)name, strlen(name));
  73     SHA1Final(sha1, &ctx);
  74 }
  75
  76 static void generate_sha1_uuid(const char *namespace, const char *name, u8 result[16])
  77 {
  78     unsigned char sha1[SHA1_DIGEST_LENGTH];
  79     struct uuid *uuid = (struct uuid *)result;
  80
  81     sha1_hash(namespace, name, (unsigned char*)sha1);
  82     memcpy(uuid, sha1, sizeof(struct uuid));
  83
  84     uuid->time_low = ntohl(uuid->time_low);
  85     uuid->time_mid = ntohs(uuid->time_mid);
  86     uuid->time_hi_and_version = ntohs(uuid->time_hi_and_version);
  87     uuid->time_hi_and_version &= 0x0FFF;
  88     uuid->time_hi_and_version |= (5 << 12);
  89     uuid->clk_seq_hi_res &= ~(1 << 6);
  90     uuid->clk_seq_hi_res |= 1 << 7;
  91 }
  92
  93 /* returns 1 if a is a power of b */
  94 static int is_power_of(int a, int b)
  95 {
  96         while (a > b) {
  97                 if (a % b)
  98                         return 0;
  99                 a /= b;
 100         }
 101
 102         return (a == b) ? 1 : 0;
 103 }
 104
 105 int bitmap_get_bit(u8 *bitmap, u32 bit)
 106 {
 107         if (bitmap[bit / 8] & (1 << (bit % 8)))
 108                 return 1;
 109
 110         return 0;
 111 }
 112
 113 void bitmap_clear_bit(u8 *bitmap, u32 bit)
 114 {
 115         bitmap[bit / 8] &= ~(1 << (bit % 8));
 116
 117         return;
 118 }
 119
 120 /* Returns 1 if the bg contains a backup superblock.  On filesystems with
 121    the sparse_super feature, only block groups 0, 1, and powers of 3, 5,
 122    and 7 have backup superblocks.  Otherwise, all block groups have backup
 123    superblocks */
 124 int ext4_bg_has_super_block(int bg)
 125 {
 126         /* Without sparse_super, every block group has a superblock */
 127         if (!(info.feat_ro_compat & EXT4_FEATURE_RO_COMPAT_SPARSE_SUPER))
 128                 return 1;
 129
 130         if (bg == 0 || bg == 1)
 131                 return 1;
 132
 133         if (is_power_of(bg, 3) || is_power_of(bg, 5) || is_power_of(bg, 7))
 134                 return 1;
 135
 136         return 0;
 137 }
 138
 139 /* Function to read the primary superblock */
 140 void read_sb(int fd, struct ext4_super_block *sb)
 141 {
 142         off64_t ret;
 143
 144         ret = lseek64(fd, 1024, SEEK_SET);
 145         if (ret < 0)
 146                 critical_error_errno("failed to seek to superblock");
 147
 148         ret = read(fd, sb, sizeof(*sb));
 149         if (ret < 0)
 150                 critical_error_errno("failed to read superblock");
 151         if (ret != sizeof(*sb))
 152                 critical_error("failed to read all of superblock");
 153 }
 154
 155 /* Function to write a primary or backup superblock at a given offset */
 156 void write_sb(int fd, unsigned long long offset, struct ext4_super_block *sb)
 157 {
 158         off64_t ret;
 159
 160         ret = lseek64(fd, offset, SEEK_SET);
 161         if (ret < 0)
 162                 critical_error_errno("failed to seek to superblock");
 163
 164         ret = write(fd, sb, sizeof(*sb));
 165         if (ret < 0)
 166                 critical_error_errno("failed to write superblock");
 167         if (ret != sizeof(*sb))
 168                 critical_error("failed to write all of superblock");
 169 }
 170
 171 /* Write the filesystem image to a file */
 172 void write_ext4_image(int fd, int gz, int sparse, int crc)
 173 {
 174         sparse_file_write(ext4_sparse_file, fd, gz, sparse, crc);
 175 }
 176
 177 /* Compute the rest of the parameters of the filesystem from the basic info */
 178 void ext4_create_fs_aux_info()
 179 {
 180         aux_info.first_data_block = (info.block_size > 1024) ? 0 : 1;
 181         aux_info.len_blocks = info.len / info.block_size;
 182         aux_info.inode_table_blocks = DIV_ROUND_UP(info.inodes_per_group * info.inode_size,
 183                 info.block_size);
 184         aux_info.groups = DIV_ROUND_UP(aux_info.len_blocks - aux_info.first_data_block,
 185                 info.blocks_per_group);
 186         aux_info.blocks_per_ind = info.block_size / sizeof(u32);
 187         aux_info.blocks_per_dind = aux_info.blocks_per_ind * aux_info.blocks_per_ind;
 188         aux_info.blocks_per_tind = aux_info.blocks_per_dind * aux_info.blocks_per_dind;
 189
 190         aux_info.bg_desc_blocks =
 191                 DIV_ROUND_UP(aux_info.groups * sizeof(struct ext2_group_desc),
 192                         info.block_size);
 193
 194         aux_info.default_i_flags = EXT4_NOATIME_FL;
 195
 196         u32 last_group_size = aux_info.len_blocks % info.blocks_per_group;
 197         u32 last_header_size = 2 + aux_info.inode_table_blocks;
 198         if (ext4_bg_has_super_block(aux_info.groups - 1))
 199                 last_header_size += 1 + aux_info.bg_desc_blocks +
 200                         info.bg_desc_reserve_blocks;
 201         if (last_group_size > 0 && last_group_size < last_header_size) {
 202                 aux_info.groups--;
 203                 aux_info.len_blocks -= last_group_size;
 204         }
 205
 206         aux_info.sb = calloc(info.block_size, 1);
 207         /* Alloc an array to hold the pointers to the backup superblocks */
 208         aux_info.backup_sb = calloc(aux_info.groups, sizeof(char *));
 209
 210         if (!aux_info.sb)
 211                 critical_error_errno("calloc");
 212
 213         aux_info.bg_desc = calloc(info.block_size, aux_info.bg_desc_blocks);
 214         if (!aux_info.bg_desc)
 215                 critical_error_errno("calloc");
 216         aux_info.xattrs = NULL;
 217 }
 218
 219 void ext4_free_fs_aux_info()
 220 {
 221         unsigned int i;
 222
 223         for (i=0; i<aux_info.groups; i++) {
 224                 if (aux_info.backup_sb[i])
 225                         free(aux_info.backup_sb[i]);
 226         }
 227         free(aux_info.sb);
 228         free(aux_info.bg_desc);
 229 }
 230
 231 /* Fill in the superblock memory buffer based on the filesystem parameters */
 232 void ext4_fill_in_sb(int real_uuid)
 233 {
 234         unsigned int i;
 235         struct ext4_super_block *sb = aux_info.sb;
 236
 237         sb->s_inodes_count = info.inodes_per_group * aux_info.groups;
 238         sb->s_blocks_count_lo = aux_info.len_blocks;
 239         sb->s_r_blocks_count_lo = 0;
 240         sb->s_free_blocks_count_lo = 0;
 241         sb->s_free_inodes_count = 0;
 242         sb->s_first_data_block = aux_info.first_data_block;
 243         sb->s_log_block_size = log_2(info.block_size / 1024);
 244         sb->s_obso_log_frag_size = log_2(info.block_size / 1024);
 245         sb->s_blocks_per_group = info.blocks_per_group;
 246         sb->s_obso_frags_per_group = info.blocks_per_group;
 247         sb->s_inodes_per_group = info.inodes_per_group;
 248         sb->s_mtime = 0;
 249         sb->s_wtime = 0;
 250         sb->s_mnt_count = 0;
 251         sb->s_max_mnt_count = 0xFFFF;
 252         sb->s_magic = EXT4_SUPER_MAGIC;
 253         sb->s_state = EXT4_VALID_FS;
 254         sb->s_errors = EXT4_ERRORS_RO;
 255         sb->s_minor_rev_level = 0;
 256         sb->s_lastcheck = 0;
 257         sb->s_checkinterval = 0;
 258         sb->s_creator_os = EXT4_OS_LINUX;
 259         sb->s_rev_level = EXT4_DYNAMIC_REV;
 260         sb->s_def_resuid = EXT4_DEF_RESUID;
 261         sb->s_def_resgid = EXT4_DEF_RESGID;
 262
 263         sb->s_first_ino = EXT4_GOOD_OLD_FIRST_INO;
 264         sb->s_inode_size = info.inode_size;
 265         sb->s_block_group_nr = 0;
 266         sb->s_feature_compat = info.feat_compat;
 267         sb->s_feature_incompat = info.feat_incompat;
 268         sb->s_feature_ro_compat = info.feat_ro_compat;
 269         if (real_uuid == 1) {
 270 #ifdef REAL_UUID
 271             uuid_generate(sb->s_uuid);
 272 #else
 273             fprintf(stderr, "Not compiled with real UUID support\n");
 274             abort();
 275 #endif
 276         } else {
 277             generate_sha1_uuid("extandroid/make_ext4fs", info.label, sb->s_uuid);
 278         }
 279         memset(sb->s_volume_name, 0, sizeof(sb->s_volume_name));
 280         strncpy(sb->s_volume_name, info.label, sizeof(sb->s_volume_name));
 281         memset(sb->s_last_mounted, 0, sizeof(sb->s_last_mounted));
 282         sb->s_algorithm_usage_bitmap = 0;
 283
 284         sb->s_reserved_gdt_blocks = info.bg_desc_reserve_blocks;
 285         sb->s_prealloc_blocks = 0;
 286         sb->s_prealloc_dir_blocks = 0;
 287
 288         //memcpy(sb->s_journal_uuid, sb->s_uuid, sizeof(sb->s_journal_uuid));
 289         if (info.feat_compat & EXT4_FEATURE_COMPAT_HAS_JOURNAL)
 290                 sb->s_journal_inum = EXT4_JOURNAL_INO;
 291         sb->s_journal_dev = 0;
 292         sb->s_last_orphan = 0;
 293         sb->s_hash_seed[0] = 0; /* FIXME */
 294         sb->s_def_hash_version = DX_HASH_TEA;
 295         sb->s_reserved_char_pad = EXT4_JNL_BACKUP_BLOCKS;
 296         sb->s_desc_size = sizeof(struct ext2_group_desc);
 297         sb->s_default_mount_opts = 0; /* FIXME */
 298         sb->s_first_meta_bg = 0;
 299         sb->s_mkfs_time = 0;
 300         //sb->s_jnl_blocks[17]; /* FIXME */
 301
 302         sb->s_blocks_count_hi = aux_info.len_blocks >> 32;
 303         sb->s_r_blocks_count_hi = 0;
 304         sb->s_free_blocks_count_hi = 0;
 305         sb->s_min_extra_isize = sizeof(struct ext4_inode) -
 306                 EXT4_GOOD_OLD_INODE_SIZE;
 307         sb->s_want_extra_isize = sizeof(struct ext4_inode) -
 308                 EXT4_GOOD_OLD_INODE_SIZE;
 309         sb->s_flags = 2;
 310         sb->s_raid_stride = 0;
 311         sb->s_mmp_interval = 0;
 312         sb->s_mmp_block = 0;
 313         sb->s_raid_stripe_width = 0;
 314         sb->s_log_groups_per_flex = 0;
 315         sb->s_kbytes_written = 0;
 316
 317         for (i = 0; i < aux_info.groups; i++) {
 318                 u64 group_start_block = aux_info.first_data_block + i *
 319                         info.blocks_per_group;
 320                 u32 header_size = 0;
 321                 if (ext4_bg_has_super_block(i)) {
 322                         if (i != 0) {
 323                                 aux_info.backup_sb[i] = calloc(info.block_size, 1);
 324                                 memcpy(aux_info.backup_sb[i], sb, info.block_size);
 325                                 /* Update the block group nr of this backup superblock */
 326                                 aux_info.backup_sb[i]->s_block_group_nr = i;
 327                                 sparse_file_add_data(ext4_sparse_file, aux_info.backup_sb[i],
 328                                                 info.block_size, group_start_block);
 329                         }
 330                         sparse_file_add_data(ext4_sparse_file, aux_info.bg_desc,
 331                                 aux_info.bg_desc_blocks * info.block_size,
 332                                 group_start_block + 1);
 333                         header_size = 1 + aux_info.bg_desc_blocks + info.bg_desc_reserve_blocks;
 334                 }
 335
 336                 aux_info.bg_desc[i].bg_block_bitmap = group_start_block + header_size;
 337                 aux_info.bg_desc[i].bg_inode_bitmap = group_start_block + header_size + 1;
 338                 aux_info.bg_desc[i].bg_inode_table = group_start_block + header_size + 2;
 339
 340                 aux_info.bg_desc[i].bg_free_blocks_count = sb->s_blocks_per_group;
 341                 aux_info.bg_desc[i].bg_free_inodes_count = sb->s_inodes_per_group;
 342                 aux_info.bg_desc[i].bg_used_dirs_count = 0;
 343         }
 344 }
 345
 346 void ext4_queue_sb(void)
 347 {
 348         /* The write_data* functions expect only block aligned calls.
 349          * This is not an issue, except when we write out the super
 350          * block on a system with a block size > 1K.  So, we need to
 351          * deal with that here.
 352          */
 353         if (info.block_size > 1024) {
 354                 u8 *buf = calloc(info.block_size, 1);
 355                 memcpy(buf + 1024, (u8*)aux_info.sb, 1024);
 356                 sparse_file_add_data(ext4_sparse_file, buf, info.block_size, 0);
 357         } else {
 358                 sparse_file_add_data(ext4_sparse_file, aux_info.sb, 1024, 1);
 359         }
 360 }
 361
 362 void ext4_parse_sb_info(struct ext4_super_block *sb)
 363 {
 364         if (sb->s_magic != EXT4_SUPER_MAGIC)
 365                 error("superblock magic incorrect");
 366
 367         if ((sb->s_state & EXT4_VALID_FS) != EXT4_VALID_FS)
 368                 error("filesystem state not valid");
 369
 370         ext4_parse_sb(sb, &info);
 371
 372         ext4_create_fs_aux_info();
 373
 374         memcpy(aux_info.sb, sb, sizeof(*sb));
 375
 376         if (aux_info.first_data_block != sb->s_first_data_block)
 377                 critical_error("first data block does not match");
 378 }
 379
 380 void ext4_create_resize_inode()
 381 {
 382         struct block_allocation *reserve_inode_alloc = create_allocation();
 383         u32 reserve_inode_len = 0;
 384         unsigned int i;
 385
 386         struct ext4_inode *inode = get_inode(EXT4_RESIZE_INO);
 387         if (inode == NULL) {
 388                 error("failed to get resize inode");
 389                 return;
 390         }
 391
 392         for (i = 0; i < aux_info.groups; i++) {
 393                 if (ext4_bg_has_super_block(i)) {
 394                         u64 group_start_block = aux_info.first_data_block + i *
 395                                 info.blocks_per_group;
 396                         u32 reserved_block_start = group_start_block + 1 +
 397                                 aux_info.bg_desc_blocks;
 398                         u32 reserved_block_len = info.bg_desc_reserve_blocks;
 399                         append_region(reserve_inode_alloc, reserved_block_start,
 400                                 reserved_block_len, i);
 401                         reserve_inode_len += reserved_block_len;
 402                 }
 403         }
 404
 405         inode_attach_resize(inode, reserve_inode_alloc);
 406
 407         inode->i_mode = S_IFREG | S_IRUSR | S_IWUSR;
 408         inode->i_links_count = 1;
 409
 410         free_alloc(reserve_inode_alloc);
 411 }
 412
 413 /* Allocate the blocks to hold a journal inode and connect them to the
 414    reserved journal inode */
 415 void ext4_create_journal_inode()
 416 {
 417         struct ext4_inode *inode = get_inode(EXT4_JOURNAL_INO);
 418         if (inode == NULL) {
 419                 error("failed to get journal inode");
 420                 return;
 421         }
 422
 423         u8 *journal_data = inode_allocate_data_extents(inode,
 424                         info.journal_blocks * info.block_size,
 425                         info.journal_blocks * info.block_size);
 426         if (!journal_data) {
 427                 error("failed to allocate extents for journal data");
 428                 return;
 429         }
 430
 431         inode->i_mode = S_IFREG | S_IRUSR | S_IWUSR;
 432         inode->i_links_count = 1;
 433
 434         journal_superblock_t *jsb = (journal_superblock_t *)journal_data;
 435         jsb->s_header.h_magic = htonl(JBD2_MAGIC_NUMBER);
 436         jsb->s_header.h_blocktype = htonl(JBD2_SUPERBLOCK_V2);
 437         jsb->s_blocksize = htonl(info.block_size);
 438         jsb->s_maxlen = htonl(info.journal_blocks);
 439         jsb->s_nr_users = htonl(1);
 440         jsb->s_first = htonl(1);
 441         jsb->s_sequence = htonl(1);
 442
 443         memcpy(aux_info.sb->s_jnl_blocks, &inode->i_block, sizeof(inode->i_block));
 444 }
 445
 446 /* Update the number of free blocks and inodes in the filesystem and in each
 447    block group */
 448 void ext4_update_free()
 449 {
 450         u32 i;
 451
 452         for (i = 0; i < aux_info.groups; i++) {
 453                 u32 bg_free_blocks = get_free_blocks(i);
 454                 u32 bg_free_inodes = get_free_inodes(i);
 455                 u16 crc;
 456
 457                 aux_info.bg_desc[i].bg_free_blocks_count = bg_free_blocks;
 458                 aux_info.sb->s_free_blocks_count_lo += bg_free_blocks;
 459
 460                 aux_info.bg_desc[i].bg_free_inodes_count = bg_free_inodes;
 461                 aux_info.sb->s_free_inodes_count += bg_free_inodes;
 462
 463                 aux_info.bg_desc[i].bg_used_dirs_count += get_directories(i);
 464
 465                 aux_info.bg_desc[i].bg_flags = get_bg_flags(i);
 466
 467                 crc = ext4_crc16(~0, aux_info.sb->s_uuid, sizeof(aux_info.sb->s_uuid));
 468                 crc = ext4_crc16(crc, &i, sizeof(i));
 469                 crc = ext4_crc16(crc, &aux_info.bg_desc[i], offsetof(struct ext2_group_desc, bg_checksum));
 470                 aux_info.bg_desc[i].bg_checksum = crc;
 471         }
 472 }
 473
 474 u64 get_block_device_size(int fd)
 475 {
 476         u64 size = 0;
 477         int ret;
 478
 479 #if defined(__linux__)
 480         ret = ioctl(fd, BLKGETSIZE64, &size);
 481 #elif defined(__APPLE__) && defined(__MACH__)
 482         ret = ioctl(fd, DKIOCGETBLOCKCOUNT, &size);
 483 #else
 484         close(fd);
 485         return 0;
 486 #endif
 487
 488         if (ret)
 489                 return 0;
 490
 491         return size;
 492 }
 493
 494 int is_block_device_fd(int fd)
 495 {
 496 #ifdef USE_MINGW
 497         return 0;
 498 #else
 499         struct stat st;
 500         int ret = fstat(fd, &st);
 501         if (ret < 0)
 502                 return 0;
 503
 504         return S_ISBLK(st.st_mode);
 505 #endif
 506 }
 507
 508 u64 get_file_size(int fd)
 509 {
 510         struct stat buf;
 511         int ret;
 512         u64 reserve_len = 0;
 513         s64 computed_size;
 514
 515         ret = fstat(fd, &buf);
 516         if (ret)
 517                 return 0;
 518
 519         if (info.len < 0)
 520                 reserve_len = -info.len;
 521
 522         if (S_ISREG(buf.st_mode))
 523                 computed_size = buf.st_size - reserve_len;
 524         else if (S_ISBLK(buf.st_mode))
 525                 computed_size = get_block_device_size(fd) - reserve_len;
 526         else
 527                 computed_size = 0;
 528
 529         if (computed_size < 0) {
 530                 warn("Computed filesystem size less than 0");
 531                 computed_size = 0;
 532         }
 533
 534         return computed_size;
 535 }
 536
 537 u64 parse_num(const char *arg)
 538 {
 539         char *endptr;
 540         u64 num = strtoull(arg, &endptr, 10);
 541         if (*endptr == 'k' || *endptr == 'K')
 542                 num *= 1024LL;
 543         else if (*endptr == 'm' || *endptr == 'M')
 544                 num *= 1024LL * 1024LL;
 545         else if (*endptr == 'g' || *endptr == 'G')
 546                 num *= 1024LL * 1024LL * 1024LL;
 547
 548         return num;
 549 }
 550
 551 int read_ext(int fd, int verbose)
 552 {
 553         off64_t ret;
 554         struct ext4_super_block sb;
 555
 556         read_sb(fd, &sb);
 557
 558         ext4_parse_sb_info(&sb);
 559
 560         ret = lseek64(fd, info.len, SEEK_SET);
 561         if (ret < 0)
 562                 critical_error_errno("failed to seek to end of input image");
 563
 564         ret = lseek64(fd, info.block_size * (aux_info.first_data_block + 1), SEEK_SET);
 565         if (ret < 0)
 566                 critical_error_errno("failed to seek to block group descriptors");
 567
 568         ret = read(fd, aux_info.bg_desc, info.block_size * aux_info.bg_desc_blocks);
 569         if (ret < 0)
 570                 critical_error_errno("failed to read block group descriptors");
 571         if (ret != (int)info.block_size * (int)aux_info.bg_desc_blocks)
 572                 critical_error("failed to read all of block group descriptors");
 573
 574         if (verbose) {
 575                 printf("Found filesystem with parameters:\n");
 576                 printf("    Size: %"PRIu64"\n", info.len);
 577                 printf("    Block size: %d\n", info.block_size);
 578                 printf("    Blocks per group: %d\n", info.blocks_per_group);
 579                 printf("    Inodes per group: %d\n", info.inodes_per_group);
 580                 printf("    Inode size: %d\n", info.inode_size);
 581                 printf("    Label: %s\n", info.label);
 582                 printf("    Blocks: %"PRIu64"\n", aux_info.len_blocks);
 583                 printf("    Block groups: %d\n", aux_info.groups);
 584                 printf("    Reserved block group size: %d\n", info.bg_desc_reserve_blocks);
 585                 printf("    Used %d/%d inodes and %d/%d blocks\n",
 586                         aux_info.sb->s_inodes_count - aux_info.sb->s_free_inodes_count,
 587                         aux_info.sb->s_inodes_count,
 588                         aux_info.sb->s_blocks_count_lo - aux_info.sb->s_free_blocks_count_lo,
 589                         aux_info.sb->s_blocks_count_lo);
 590         }
 591
 592         return 0;
 593 }
 594