lib/ext2fs/rw_bitmaps.c

   1 /*
   2  * rw_bitmaps.c --- routines to read and write the  inode and block bitmaps.
   3  *
   4  * Copyright (C) 1993, 1994, 1994, 1996 Theodore Ts'o.
   5  *
   6  * %Begin-Header%
   7  * This file may be redistributed under the terms of the GNU Library
   8  * General Public License, version 2.
   9  * %End-Header%
  10  */
  11
  12 #include "config.h"
  13 #include <stdio.h>
  14 #include <string.h>
  15 #if HAVE_UNISTD_H
  16 #include <unistd.h>
  17 #endif
  18 #include <fcntl.h>
  19 #include <time.h>
  20 #ifdef HAVE_SYS_STAT_H
  21 #include <sys/stat.h>
  22 #endif
  23 #ifdef HAVE_SYS_TYPES_H
  24 #include <sys/types.h>
  25 #endif
  26 #ifdef HAVE_PTHREAD_H
  27 #include <pthread.h>
  28 #endif
  29
  30 #include "ext2_fs.h"
  31 #include "ext2fs.h"
  32 #include "e2image.h"
  33
  34 #ifdef HAVE_PTHREAD
  35 typedef pthread_mutex_t mutex_t;
  36
  37 static void unix_pthread_mutex_lock(mutex_t *mutex)
  38 {
  39         if (mutex)
  40                 pthread_mutex_lock(mutex);
  41 }
  42 static void unix_pthread_mutex_unlock(mutex_t *mutex)
  43 {
  44         if (mutex)
  45                 pthread_mutex_unlock(mutex);
  46 }
  47 #else
  48 typedef int mutex_t;
  49 #define unix_pthread_mutex_lock(mutex_t) do {} while (0)
  50 #define unix_pthread_mutex_unlock(mutex_t) do {} while (0)
  51 #endif
  52
  53 static errcode_t write_bitmaps(ext2_filsys fs, int do_inode, int do_block)
  54 {
  55         dgrp_t          i;
  56         unsigned int    j;
  57         int             block_nbytes, inode_nbytes;
  58         unsigned int    nbits;
  59         errcode_t       retval;
  60         char            *block_buf = NULL, *inode_buf = NULL;
  61         int             csum_flag;
  62         blk64_t         blk;
  63         blk64_t         blk_itr = EXT2FS_B2C(fs, fs->super->s_first_data_block);
  64         ext2_ino_t      ino_itr = 1;
  65
  66         EXT2_CHECK_MAGIC(fs, EXT2_ET_MAGIC_EXT2FS_FILSYS);
  67
  68         if (!(fs->flags & EXT2_FLAG_RW))
  69                 return EXT2_ET_RO_FILSYS;
  70
  71         csum_flag = ext2fs_has_group_desc_csum(fs);
  72
  73         inode_nbytes = block_nbytes = 0;
  74         if (do_block) {
  75                 block_nbytes = EXT2_CLUSTERS_PER_GROUP(fs->super) / 8;
  76                 retval = io_channel_alloc_buf(fs->io, 0, &block_buf);
  77                 if (retval)
  78                         goto errout;
  79                 memset(block_buf, 0xff, fs->blocksize);
  80         }
  81         if (do_inode) {
  82                 inode_nbytes = (size_t)
  83                         ((EXT2_INODES_PER_GROUP(fs->super)+7) / 8);
  84                 retval = io_channel_alloc_buf(fs->io, 0, &inode_buf);
  85                 if (retval)
  86                         goto errout;
  87                 memset(inode_buf, 0xff, fs->blocksize);
  88         }
  89
  90         for (i = 0; i < fs->group_desc_count; i++) {
  91                 if (!do_block)
  92                         goto skip_block_bitmap;
  93
  94                 if (csum_flag && ext2fs_bg_flags_test(fs, i, EXT2_BG_BLOCK_UNINIT)
  95                     )
  96                         goto skip_this_block_bitmap;
  97
  98                 retval = ext2fs_get_block_bitmap_range2(fs->block_map,
  99                                 blk_itr, block_nbytes << 3, block_buf);
 100                 if (retval)
 101                         goto errout;
 102
 103                 if (i == fs->group_desc_count - 1) {
 104                         /* Force bitmap padding for the last group */
 105                         nbits = EXT2FS_NUM_B2C(fs,
 106                                 ((ext2fs_blocks_count(fs->super)
 107                                   - (__u64) fs->super->s_first_data_block)
 108                                  % (__u64) EXT2_BLOCKS_PER_GROUP(fs->super)));
 109                         if (nbits)
 110                                 for (j = nbits; j < fs->blocksize * 8; j++)
 111                                         ext2fs_set_bit(j, block_buf);
 112                 }
 113
 114                 retval = ext2fs_block_bitmap_csum_set(fs, i, block_buf,
 115                                                       block_nbytes);
 116                 if (retval)
 117                         return retval;
 118                 ext2fs_group_desc_csum_set(fs, i);
 119                 fs->flags |= EXT2_FLAG_DIRTY;
 120
 121                 blk = ext2fs_block_bitmap_loc(fs, i);
 122                 if (blk && blk < ext2fs_blocks_count(fs->super)) {
 123                         retval = io_channel_write_blk64(fs->io, blk, 1,
 124                                                         block_buf);
 125                         if (retval) {
 126                                 retval = EXT2_ET_BLOCK_BITMAP_WRITE;
 127                                 goto errout;
 128                         }
 129                 }
 130         skip_this_block_bitmap:
 131                 blk_itr += block_nbytes << 3;
 132         skip_block_bitmap:
 133
 134                 if (!do_inode)
 135                         continue;
 136
 137                 if (csum_flag && ext2fs_bg_flags_test(fs, i, EXT2_BG_INODE_UNINIT)
 138                     )
 139                         goto skip_this_inode_bitmap;
 140
 141                 retval = ext2fs_get_inode_bitmap_range2(fs->inode_map,
 142                                 ino_itr, inode_nbytes << 3, inode_buf);
 143                 if (retval)
 144                         goto errout;
 145
 146                 retval = ext2fs_inode_bitmap_csum_set(fs, i, inode_buf,
 147                                                       inode_nbytes);
 148                 if (retval)
 149                         goto errout;
 150                 ext2fs_group_desc_csum_set(fs, i);
 151                 fs->flags |= EXT2_FLAG_DIRTY;
 152
 153                 blk = ext2fs_inode_bitmap_loc(fs, i);
 154                 if (blk && blk < ext2fs_blocks_count(fs->super)) {
 155                         retval = io_channel_write_blk64(fs->io, blk, 1,
 156                                                       inode_buf);
 157                         if (retval) {
 158                                 retval = EXT2_ET_INODE_BITMAP_WRITE;
 159                                 goto errout;
 160                         }
 161                 }
 162         skip_this_inode_bitmap:
 163                 ino_itr += inode_nbytes << 3;
 164
 165         }
 166         if (do_block) {
 167                 fs->flags &= ~EXT2_FLAG_BB_DIRTY;
 168                 ext2fs_free_mem(&block_buf);
 169         }
 170         if (do_inode) {
 171                 fs->flags &= ~EXT2_FLAG_IB_DIRTY;
 172                 ext2fs_free_mem(&inode_buf);
 173         }
 174         return 0;
 175 errout:
 176         if (inode_buf)
 177                 ext2fs_free_mem(&inode_buf);
 178         if (block_buf)
 179                 ext2fs_free_mem(&block_buf);
 180         return retval;
 181 }
 182
 183 static errcode_t mark_uninit_bg_group_blocks(ext2_filsys fs)
 184 {
 185         dgrp_t                  i;
 186         blk64_t                 blk;
 187         ext2fs_block_bitmap     bmap = fs->block_map;
 188
 189         for (i = 0; i < fs->group_desc_count; i++) {
 190                 if (!ext2fs_bg_flags_test(fs, i, EXT2_BG_BLOCK_UNINIT))
 191                         continue;
 192
 193                 ext2fs_reserve_super_and_bgd(fs, i, bmap);
 194
 195                 /*
 196                  * Mark the blocks used for the inode table
 197                  */
 198                 blk = ext2fs_inode_table_loc(fs, i);
 199                 if (blk)
 200                         ext2fs_mark_block_bitmap_range2(bmap, blk,
 201                                                 fs->inode_blocks_per_group);
 202
 203                 /*
 204                  * Mark block used for the block bitmap
 205                  */
 206                 blk = ext2fs_block_bitmap_loc(fs, i);
 207                 if (blk && blk < ext2fs_blocks_count(fs->super))
 208                         ext2fs_mark_block_bitmap2(bmap, blk);
 209
 210                 /*
 211                  * Mark block used for the inode bitmap
 212                  */
 213                 blk = ext2fs_inode_bitmap_loc(fs, i);
 214                 if (blk && blk < ext2fs_blocks_count(fs->super))
 215                         ext2fs_mark_block_bitmap2(bmap, blk);
 216         }
 217         return 0;
 218 }
 219
 220 static int bitmap_tail_verify(unsigned char *bitmap, int first, int last)
 221 {
 222         int i;
 223
 224         for (i = first; i <= last; i++)
 225                 if (bitmap[i] != 0xff)
 226                         return 0;
 227         return 1;
 228 }
 229
 230 static errcode_t read_bitmaps_range_prepare(ext2_filsys fs, int flags)
 231 {
 232         errcode_t retval;
 233         int block_nbytes = EXT2_CLUSTERS_PER_GROUP(fs->super) / 8;
 234         int inode_nbytes = EXT2_INODES_PER_GROUP(fs->super) / 8;
 235         char *buf;
 236
 237         EXT2_CHECK_MAGIC(fs, EXT2_ET_MAGIC_EXT2FS_FILSYS);
 238
 239         if ((block_nbytes > (int) fs->blocksize) ||
 240             (inode_nbytes > (int) fs->blocksize))
 241                 return EXT2_ET_CORRUPT_SUPERBLOCK;
 242
 243         fs->write_bitmaps = ext2fs_write_bitmaps;
 244
 245         retval = ext2fs_get_mem(strlen(fs->device_name) + 80, &buf);
 246         if (retval)
 247                 return retval;
 248
 249         if (flags & EXT2FS_BITMAPS_BLOCK) {
 250                 if (fs->block_map)
 251                         ext2fs_free_block_bitmap(fs->block_map);
 252                 strcpy(buf, "block bitmap for ");
 253                 strcat(buf, fs->device_name);
 254                 retval = ext2fs_allocate_block_bitmap(fs, buf, &fs->block_map);
 255                 if (retval)
 256                         goto cleanup;
 257         }
 258
 259         if (flags & EXT2FS_BITMAPS_INODE) {
 260                 if (fs->inode_map)
 261                         ext2fs_free_inode_bitmap(fs->inode_map);
 262                 strcpy(buf, "inode bitmap for ");
 263                 strcat(buf, fs->device_name);
 264                 retval = ext2fs_allocate_inode_bitmap(fs, buf, &fs->inode_map);
 265                 if (retval)
 266                         goto cleanup;
 267         }
 268         ext2fs_free_mem(&buf);
 269         return retval;
 270
 271 cleanup:
 272         if (flags & EXT2FS_BITMAPS_BLOCK) {
 273                 ext2fs_free_block_bitmap(fs->block_map);
 274                 fs->block_map = 0;
 275         }
 276         if (flags & EXT2FS_BITMAPS_INODE) {
 277                 ext2fs_free_inode_bitmap(fs->inode_map);
 278                 fs->inode_map = 0;
 279         }
 280         ext2fs_free_mem(&buf);
 281         return retval;
 282 }
 283
 284 static errcode_t read_bitmaps_range_start(ext2_filsys fs, int flags,
 285                                           dgrp_t start, dgrp_t end,
 286                                           mutex_t *mutex,
 287                                           int *tail_flags)
 288 {
 289         dgrp_t i;
 290         char *block_bitmap = 0, *inode_bitmap = 0;
 291         errcode_t retval = 0;
 292         int block_nbytes = EXT2_CLUSTERS_PER_GROUP(fs->super) / 8;
 293         int inode_nbytes = EXT2_INODES_PER_GROUP(fs->super) / 8;
 294         int csum_flag;
 295         unsigned int    cnt;
 296         blk64_t blk;
 297         blk64_t blk_itr = EXT2FS_B2C(fs, fs->super->s_first_data_block);
 298         blk64_t   blk_cnt;
 299         ext2_ino_t ino_itr = 1;
 300         ext2_ino_t ino_cnt;
 301
 302         csum_flag = ext2fs_has_group_desc_csum(fs);
 303
 304         if (flags & EXT2FS_BITMAPS_BLOCK) {
 305                 retval = io_channel_alloc_buf(fs->io, 0, &block_bitmap);
 306                 if (retval)
 307                         goto cleanup;
 308         } else {
 309                 block_nbytes = 0;
 310         }
 311
 312         if (flags & EXT2FS_BITMAPS_INODE) {
 313                 retval = io_channel_alloc_buf(fs->io, 0, &inode_bitmap);
 314                 if (retval)
 315                         goto cleanup;
 316         } else {
 317                 inode_nbytes = 0;
 318         }
 319
 320         /* io should be null */
 321         if (fs->flags & EXT2_FLAG_IMAGE_FILE) {
 322                 blk = (ext2fs_le32_to_cpu(fs->image_header->offset_inodemap) / fs->blocksize);
 323                 ino_cnt = fs->super->s_inodes_count;
 324                 while (inode_bitmap && ino_cnt > 0) {
 325                         retval = io_channel_read_blk64(fs->image_io, blk++,
 326                                                      1, inode_bitmap);
 327                         if (retval)
 328                                 goto cleanup;
 329                         cnt = fs->blocksize << 3;
 330                         if (cnt > ino_cnt)
 331                                 cnt = ino_cnt;
 332                         retval = ext2fs_set_inode_bitmap_range2(fs->inode_map,
 333                                                ino_itr, cnt, inode_bitmap);
 334                         if (retval)
 335                                 goto cleanup;
 336                         ino_itr += cnt;
 337                         ino_cnt -= cnt;
 338                 }
 339                 blk = (ext2fs_le32_to_cpu(fs->image_header->offset_blockmap) /
 340                        fs->blocksize);
 341                 blk_cnt = EXT2_GROUPS_TO_CLUSTERS(fs->super,
 342                                                   fs->group_desc_count);
 343                 while (block_bitmap && blk_cnt > 0) {
 344                         retval = io_channel_read_blk64(fs->image_io, blk++,
 345                                                      1, block_bitmap);
 346                         if (retval)
 347                                 goto cleanup;
 348                         cnt = fs->blocksize << 3;
 349                         if (cnt > blk_cnt)
 350                                 cnt = blk_cnt;
 351                         retval = ext2fs_set_block_bitmap_range2(fs->block_map,
 352                                        blk_itr, cnt, block_bitmap);
 353                         if (retval)
 354                                 goto cleanup;
 355                         blk_itr += cnt;
 356                         blk_cnt -= cnt;
 357                 }
 358                 goto cleanup;
 359         }
 360
 361         blk_itr += ((blk64_t)start * (block_nbytes << 3));
 362         ino_itr += ((blk64_t)start * (inode_nbytes << 3));
 363         for (i = start; i <= end; i++) {
 364                 if (block_bitmap) {
 365                         blk = ext2fs_block_bitmap_loc(fs, i);
 366                         if ((csum_flag &&
 367                              ext2fs_bg_flags_test(fs, i, EXT2_BG_BLOCK_UNINIT) &&
 368                              ext2fs_group_desc_csum_verify(fs, i)) ||
 369                             (blk >= ext2fs_blocks_count(fs->super)))
 370                                 blk = 0;
 371                         if (blk) {
 372                                 retval = io_channel_read_blk64(fs->io, blk,
 373                                                                1, block_bitmap);
 374                                 if (retval) {
 375                                         retval = EXT2_ET_BLOCK_BITMAP_READ;
 376                                         goto cleanup;
 377                                 }
 378                                 /* verify block bitmap checksum */
 379                                 if (!(fs->flags &
 380                                       EXT2_FLAG_IGNORE_CSUM_ERRORS) &&
 381                                     !ext2fs_block_bitmap_csum_verify(fs, i,
 382                                                 block_bitmap, block_nbytes)) {
 383                                         retval =
 384                                         EXT2_ET_BLOCK_BITMAP_CSUM_INVALID;
 385                                         goto cleanup;
 386                                 }
 387                                 if (!bitmap_tail_verify((unsigned char *) block_bitmap,
 388                                                         block_nbytes, fs->blocksize - 1))
 389                                         *tail_flags |= EXT2_FLAG_BBITMAP_TAIL_PROBLEM;
 390                         } else
 391                                 memset(block_bitmap, 0, block_nbytes);
 392                         cnt = block_nbytes << 3;
 393                         unix_pthread_mutex_lock(mutex);
 394                         retval = ext2fs_set_block_bitmap_range2(fs->block_map,
 395                                                blk_itr, cnt, block_bitmap);
 396                         unix_pthread_mutex_unlock(mutex);
 397                         if (retval)
 398                                 goto cleanup;
 399                         blk_itr += block_nbytes << 3;
 400                 }
 401                 if (inode_bitmap) {
 402                         blk = ext2fs_inode_bitmap_loc(fs, i);
 403                         if ((csum_flag &&
 404                              ext2fs_bg_flags_test(fs, i, EXT2_BG_INODE_UNINIT) &&
 405                              ext2fs_group_desc_csum_verify(fs, i)) ||
 406                             (blk >= ext2fs_blocks_count(fs->super)))
 407                                 blk = 0;
 408                         if (blk) {
 409                                 retval = io_channel_read_blk64(fs->io, blk,
 410                                                                1, inode_bitmap);
 411                                 if (retval) {
 412                                         retval = EXT2_ET_INODE_BITMAP_READ;
 413                                         goto cleanup;
 414                                 }
 415
 416                                 /* verify inode bitmap checksum */
 417                                 if (!(fs->flags &
 418                                       EXT2_FLAG_IGNORE_CSUM_ERRORS) &&
 419                                     !ext2fs_inode_bitmap_csum_verify(fs, i,
 420                                                 inode_bitmap, inode_nbytes)) {
 421                                         retval =
 422                                         EXT2_ET_INODE_BITMAP_CSUM_INVALID;
 423                                         goto cleanup;
 424                                 }
 425                                 if (!bitmap_tail_verify((unsigned char *) inode_bitmap,
 426                                                         inode_nbytes, fs->blocksize - 1))
 427                                         *tail_flags |= EXT2_FLAG_IBITMAP_TAIL_PROBLEM;
 428                         } else
 429                                 memset(inode_bitmap, 0, inode_nbytes);
 430                         cnt = inode_nbytes << 3;
 431                         unix_pthread_mutex_lock(mutex);
 432                         retval = ext2fs_set_inode_bitmap_range2(fs->inode_map,
 433                                                ino_itr, cnt, inode_bitmap);
 434                         unix_pthread_mutex_unlock(mutex);
 435                         if (retval)
 436                                 goto cleanup;
 437                         ino_itr += inode_nbytes << 3;
 438                 }
 439         }
 440
 441 cleanup:
 442         if (inode_bitmap)
 443                 ext2fs_free_mem(&inode_bitmap);
 444         if (block_bitmap)
 445                 ext2fs_free_mem(&block_bitmap);
 446         return retval;
 447 }
 448
 449 static errcode_t read_bitmaps_range_end(ext2_filsys fs, int flags,
 450                                         int tail_flags)
 451 {
 452         errcode_t retval;
 453
 454         /* Mark group blocks for any BLOCK_UNINIT groups */
 455         if (flags & EXT2FS_BITMAPS_BLOCK) {
 456                 retval = mark_uninit_bg_group_blocks(fs);
 457                 if (retval)
 458                         return retval;
 459                 fs->flags &= ~EXT2_FLAG_BBITMAP_TAIL_PROBLEM;
 460         }
 461         if (flags & EXT2FS_BITMAPS_INODE)
 462                 fs->flags &= ~EXT2_FLAG_IBITMAP_TAIL_PROBLEM;
 463         fs->flags |= tail_flags;
 464
 465         return 0;
 466 }
 467
 468 static void read_bitmaps_cleanup_on_error(ext2_filsys fs, int flags)
 469 {
 470         if (flags & EXT2FS_BITMAPS_BLOCK) {
 471                 ext2fs_free_block_bitmap(fs->block_map);
 472                 fs->block_map = 0;
 473         }
 474         if (flags & EXT2FS_BITMAPS_INODE) {
 475                 ext2fs_free_inode_bitmap(fs->inode_map);
 476                 fs->inode_map = 0;
 477         }
 478 }
 479
 480 static errcode_t read_bitmaps_range(ext2_filsys fs, int flags,
 481                                     dgrp_t start, dgrp_t end)
 482 {
 483         errcode_t retval;
 484         int tail_flags = 0;
 485
 486         retval = read_bitmaps_range_prepare(fs, flags);
 487         if (retval)
 488                 return retval;
 489
 490         retval = read_bitmaps_range_start(fs, flags, start, end,
 491                                           NULL, &tail_flags);
 492         if (retval == 0)
 493                 retval = read_bitmaps_range_end(fs, flags, tail_flags);
 494         if (retval)
 495                 read_bitmaps_cleanup_on_error(fs, flags);
 496         return retval;
 497 }
 498
 499 #ifdef HAVE_PTHREAD
 500 struct read_bitmaps_thread_info {
 501         ext2_filsys     rbt_fs;
 502         int             rbt_flags;
 503         dgrp_t          rbt_grp_start;
 504         dgrp_t          rbt_grp_end;
 505         errcode_t       rbt_retval;
 506         pthread_mutex_t *rbt_mutex;
 507         int             rbt_tail_flags;
 508 };
 509
 510 static void *read_bitmaps_thread(void *data)
 511 {
 512         struct read_bitmaps_thread_info *rbt = data;
 513
 514         rbt->rbt_retval = read_bitmaps_range_start(rbt->rbt_fs, rbt->rbt_flags,
 515                                 rbt->rbt_grp_start, rbt->rbt_grp_end,
 516                                 rbt->rbt_mutex, &rbt->rbt_tail_flags);
 517         return NULL;
 518 }
 519 #endif
 520
 521 errcode_t ext2fs_rw_bitmaps(ext2_filsys fs, int flags, int num_threads)
 522 {
 523 #ifdef HAVE_PTHREAD
 524         pthread_attr_t  attr;
 525         pthread_t *thread_ids = NULL;
 526         struct read_bitmaps_thread_info *thread_infos = NULL;
 527         pthread_mutex_t rbt_mutex = PTHREAD_MUTEX_INITIALIZER;
 528         errcode_t retval;
 529         errcode_t rc;
 530         unsigned flexbg_size = 1U << fs->super->s_log_groups_per_flex;
 531         dgrp_t average_group;
 532         int i, tail_flags = 0;
 533 #endif
 534
 535         if (flags & ~EXT2FS_BITMAPS_VALID_FLAGS)
 536                 return EXT2_ET_INVALID_ARGUMENT;
 537
 538         if (ext2fs_has_feature_journal_dev(fs->super))
 539                 return EXT2_ET_EXTERNAL_JOURNAL_NOSUPP;
 540
 541         if (flags & EXT2FS_BITMAPS_WRITE)
 542                 return write_bitmaps(fs, flags & EXT2FS_BITMAPS_INODE,
 543                                      flags & EXT2FS_BITMAPS_BLOCK);
 544
 545 #ifdef HAVE_PTHREAD
 546         if (((fs->io->flags & CHANNEL_FLAGS_THREADS) == 0) ||
 547             (num_threads == 1) || (fs->flags & EXT2_FLAG_IMAGE_FILE))
 548                 goto fallback;
 549
 550 #if defined(HAVE_SYSCONF) && defined(_SC_NPROCESSORS_CONF)
 551         if (num_threads < 0)
 552                 num_threads = sysconf(_SC_NPROCESSORS_CONF);
 553 #endif
 554         /*
 555          * Guess for now; eventually we should probably define
 556          * ext2fs_get_num_cpus() and teach it how to get this info on
 557          * MacOS, FreeBSD, etc.
 558          * ref: https://stackoverflow.com/questions/150355
 559          */
 560         if (num_threads < 0)
 561                 num_threads = 4;
 562
 563         if ((unsigned) num_threads > fs->group_desc_count)
 564                 num_threads = fs->group_desc_count;
 565         average_group = fs->group_desc_count / num_threads;
 566         if (ext2fs_has_feature_flex_bg(fs->super)) {
 567                 average_group = (average_group / flexbg_size) * flexbg_size;
 568         }
 569         if ((num_threads <= 1) || (average_group == 0))
 570                 goto fallback;
 571
 572         io_channel_set_options(fs->io, "cache=off");
 573         retval = pthread_attr_init(&attr);
 574         if (retval)
 575                 return retval;
 576
 577         thread_ids = calloc(sizeof(pthread_t), num_threads);
 578         if (!thread_ids)
 579                 return ENOMEM;
 580
 581         thread_infos = calloc(sizeof(struct read_bitmaps_thread_info),
 582                                 num_threads);
 583         if (!thread_infos)
 584                 goto out;
 585
 586         retval = read_bitmaps_range_prepare(fs, flags);
 587         if (retval)
 588                 goto out;
 589
 590 //      fprintf(stdout, "Multiple threads triggered to read bitmaps\n");
 591         for (i = 0; i < num_threads; i++) {
 592                 thread_infos[i].rbt_fs = fs;
 593                 thread_infos[i].rbt_flags = flags;
 594                 thread_infos[i].rbt_mutex = &rbt_mutex;
 595                 thread_infos[i].rbt_tail_flags = 0;
 596                 if (i == 0)
 597                         thread_infos[i].rbt_grp_start = 0;
 598                 else
 599                         thread_infos[i].rbt_grp_start = average_group * i + 1;
 600
 601                 if (i == num_threads - 1)
 602                         thread_infos[i].rbt_grp_end = fs->group_desc_count - 1;
 603                 else
 604                         thread_infos[i].rbt_grp_end = average_group * (i + 1);
 605                 retval = pthread_create(&thread_ids[i], &attr,
 606                                         &read_bitmaps_thread, &thread_infos[i]);
 607                 if (retval)
 608                         break;
 609         }
 610         for (i = 0; i < num_threads; i++) {
 611                 if (!thread_ids[i])
 612                         break;
 613                 rc = pthread_join(thread_ids[i], NULL);
 614                 if (rc && !retval)
 615                         retval = rc;
 616                 rc = thread_infos[i].rbt_retval;
 617                 if (rc && !retval)
 618                         retval = rc;
 619                 tail_flags |= thread_infos[i].rbt_tail_flags;
 620         }
 621 out:
 622         rc = pthread_attr_destroy(&attr);
 623         if (rc && !retval)
 624                 retval = rc;
 625         free(thread_infos);
 626         free(thread_ids);
 627
 628         if (retval == 0)
 629                 retval = read_bitmaps_range_end(fs, flags, tail_flags);
 630         if (retval)
 631                 read_bitmaps_cleanup_on_error(fs, flags);
 632         /* XXX should save and restore cache setting */
 633         io_channel_set_options(fs->io, "cache=on");
 634         return retval;
 635 fallback:
 636 #endif /* HAVE_PTHREAD */
 637         return read_bitmaps_range(fs, flags, 0, fs->group_desc_count - 1);
 638 }
 639
 640 errcode_t ext2fs_read_inode_bitmap(ext2_filsys fs)
 641 {
 642         return ext2fs_rw_bitmaps(fs, EXT2FS_BITMAPS_INODE, -1);
 643 }
 644
 645 errcode_t ext2fs_read_block_bitmap(ext2_filsys fs)
 646 {
 647         return ext2fs_rw_bitmaps(fs, EXT2FS_BITMAPS_BLOCK, -1);
 648 }
 649
 650 errcode_t ext2fs_write_inode_bitmap(ext2_filsys fs)
 651 {
 652         return write_bitmaps(fs, 1, 0);
 653 }
 654
 655 errcode_t ext2fs_write_block_bitmap (ext2_filsys fs)
 656 {
 657         return write_bitmaps(fs, 0, 1);
 658 }
 659
 660 errcode_t ext2fs_read_bitmaps(ext2_filsys fs)
 661 {
 662         int flags = 0;
 663
 664         if (!fs->inode_map)
 665                 flags |= EXT2FS_BITMAPS_INODE;
 666         if (!fs->block_map)
 667                 flags |= EXT2FS_BITMAPS_BLOCK;
 668         if (flags == 0)
 669                 return 0;
 670         return ext2fs_rw_bitmaps(fs, flags, -1);
 671 }
 672
 673 errcode_t ext2fs_write_bitmaps(ext2_filsys fs)
 674 {
 675         int do_inode = fs->inode_map && ext2fs_test_ib_dirty(fs);
 676         int do_block = fs->block_map && ext2fs_test_bb_dirty(fs);
 677
 678         if (!do_inode && !do_block)
 679                 return 0;
 680
 681         return write_bitmaps(fs, do_inode, do_block);
 682 }