lib/ext2fs/closefs.c

   1 /*
   2  * closefs.c --- close an ext2 filesystem
   3  *
   4  * Copyright (C) 1993, 1994, 1995, 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 #if HAVE_UNISTD_H
  15 #include <unistd.h>
  16 #endif
  17 #include <time.h>
  18 #include <string.h>
  19
  20 #include "ext2_fs.h"
  21 #include "ext2fsP.h"
  22
  23 static int test_root(unsigned int a, unsigned int b)
  24 {
  25         while (1) {
  26                 if (a < b)
  27                         return 0;
  28                 if (a == b)
  29                         return 1;
  30                 if (a % b)
  31                         return 0;
  32                 a = a / b;
  33         }
  34 }
  35
  36 int ext2fs_bg_has_super(ext2_filsys fs, dgrp_t group)
  37 {
  38         if (group == 0)
  39                 return 1;
  40         if (fs->super->s_feature_compat & EXT4_FEATURE_COMPAT_SPARSE_SUPER2) {
  41                 if (group == fs->super->s_backup_bgs[0] ||
  42                     group == fs->super->s_backup_bgs[1])
  43                         return 1;
  44                 return 0;
  45         }
  46         if ((group <= 1) || !(fs->super->s_feature_ro_compat &
  47                               EXT2_FEATURE_RO_COMPAT_SPARSE_SUPER))
  48                 return 1;
  49         if (!(group & 1))
  50                 return 0;
  51         if (test_root(group, 3) || (test_root(group, 5)) ||
  52             test_root(group, 7))
  53                 return 1;
  54
  55         return 0;
  56 }
  57
  58 /*
  59  * ext2fs_super_and_bgd_loc2()
  60  * @fs:                 ext2 fs pointer
  61  * @group               given block group
  62  * @ret_super_blk:      if !NULL, returns super block location
  63  * @ret_old_desc_blk:   if !NULL, returns location of the old block
  64  *                      group descriptor
  65  * @ret_new_desc_blk:   if !NULL, returns location of meta_bg block
  66  *                      group descriptor
  67  * @ret_used_blks:      if !NULL, returns number of blocks used by
  68  *                      super block and group_descriptors.
  69  *
  70  * Returns errcode_t of 0
  71  */
  72 errcode_t ext2fs_super_and_bgd_loc2(ext2_filsys fs,
  73                                            dgrp_t group,
  74                                            blk64_t *ret_super_blk,
  75                                            blk64_t *ret_old_desc_blk,
  76                                            blk64_t *ret_new_desc_blk,
  77                                            blk_t *ret_used_blks)
  78 {
  79         blk64_t group_block, super_blk = 0, old_desc_blk = 0, new_desc_blk = 0;
  80         unsigned int meta_bg, meta_bg_size;
  81         blk_t   numblocks = 0;
  82         blk64_t old_desc_blocks;
  83         int     has_super;
  84
  85         group_block = ext2fs_group_first_block2(fs, group);
  86         if (group_block == 0 && fs->blocksize == 1024)
  87                 group_block = 1; /* Deal with 1024 blocksize && bigalloc */
  88
  89         if (fs->super->s_feature_incompat & EXT2_FEATURE_INCOMPAT_META_BG)
  90                 old_desc_blocks = fs->super->s_first_meta_bg;
  91         else
  92                 old_desc_blocks =
  93                         fs->desc_blocks + fs->super->s_reserved_gdt_blocks;
  94
  95         has_super = ext2fs_bg_has_super(fs, group);
  96
  97         if (has_super) {
  98                 super_blk = group_block;
  99                 numblocks++;
 100         }
 101         meta_bg_size = EXT2_DESC_PER_BLOCK(fs->super);
 102         meta_bg = group / meta_bg_size;
 103
 104         if (!(fs->super->s_feature_incompat & EXT2_FEATURE_INCOMPAT_META_BG) ||
 105             (meta_bg < fs->super->s_first_meta_bg)) {
 106                 if (has_super) {
 107                         old_desc_blk = group_block + 1;
 108                         numblocks += old_desc_blocks;
 109                 }
 110         } else {
 111                 if (((group % meta_bg_size) == 0) ||
 112                     ((group % meta_bg_size) == 1) ||
 113                     ((group % meta_bg_size) == (meta_bg_size-1))) {
 114                         if (has_super)
 115                                 has_super = 1;
 116                         new_desc_blk = group_block + has_super;
 117                         numblocks++;
 118                 }
 119         }
 120
 121         if (ret_super_blk)
 122                 *ret_super_blk = super_blk;
 123         if (ret_old_desc_blk)
 124                 *ret_old_desc_blk = old_desc_blk;
 125         if (ret_new_desc_blk)
 126                 *ret_new_desc_blk = new_desc_blk;
 127         if (ret_used_blks)
 128                 *ret_used_blks = numblocks;
 129
 130         return 0;
 131 }
 132
 133 /*
 134  * This function returns the location of the superblock, block group
 135  * descriptors for a given block group.  It currently returns the
 136  * number of free blocks assuming that inode table and allocation
 137  * bitmaps will be in the group.  This is not necessarily the case
 138  * when the flex_bg feature is enabled, so callers should take care!
 139  * It was only really intended for use by mke2fs, and even there it's
 140  * not that useful.
 141  *
 142  * The ext2fs_super_and_bgd_loc2() function is 64-bit block number
 143  * capable and returns the number of blocks used by super block and
 144  * group descriptors.
 145  */
 146 int ext2fs_super_and_bgd_loc(ext2_filsys fs,
 147                              dgrp_t group,
 148                              blk_t *ret_super_blk,
 149                              blk_t *ret_old_desc_blk,
 150                              blk_t *ret_new_desc_blk,
 151                              int *ret_meta_bg)
 152 {
 153         blk64_t ret_super_blk2;
 154         blk64_t ret_old_desc_blk2;
 155         blk64_t ret_new_desc_blk2;
 156         blk_t ret_used_blks;
 157         blk_t numblocks;
 158         unsigned int meta_bg_size;
 159
 160         ext2fs_super_and_bgd_loc2(fs, group, &ret_super_blk2,
 161                                         &ret_old_desc_blk2,
 162                                         &ret_new_desc_blk2,
 163                                         &ret_used_blks);
 164
 165         numblocks = ext2fs_group_blocks_count(fs, group);
 166
 167         if (ret_super_blk)
 168                 *ret_super_blk = (blk_t)ret_super_blk2;
 169         if (ret_old_desc_blk)
 170                 *ret_old_desc_blk = (blk_t)ret_old_desc_blk2;
 171         if (ret_new_desc_blk)
 172                 *ret_new_desc_blk = (blk_t)ret_new_desc_blk2;
 173         if (ret_meta_bg) {
 174                 meta_bg_size = EXT2_DESC_PER_BLOCK(fs->super);
 175                 *ret_meta_bg = group / meta_bg_size;
 176         }
 177
 178         numblocks -= 2 + fs->inode_blocks_per_group + ret_used_blks;
 179
 180         return numblocks;
 181 }
 182
 183 /*
 184  * This function forces out the primary superblock.  We need to only
 185  * write out those fields which we have changed, since if the
 186  * filesystem is mounted, it may have changed some of the other
 187  * fields.
 188  *
 189  * It takes as input a superblock which has already been byte swapped
 190  * (if necessary).
 191  *
 192  */
 193 static errcode_t write_primary_superblock(ext2_filsys fs,
 194                                           struct ext2_super_block *super)
 195 {
 196         __u16           *old_super, *new_super;
 197         int             check_idx, write_idx, size;
 198         errcode_t       retval;
 199
 200         if (!fs->io->manager->write_byte || !fs->orig_super) {
 201         fallback:
 202                 io_channel_set_blksize(fs->io, SUPERBLOCK_OFFSET);
 203                 retval = io_channel_write_blk64(fs->io, 1, -SUPERBLOCK_SIZE,
 204                                               super);
 205                 io_channel_set_blksize(fs->io, fs->blocksize);
 206                 return retval;
 207         }
 208
 209         old_super = (__u16 *) fs->orig_super;
 210         new_super = (__u16 *) super;
 211
 212         for (check_idx = 0; check_idx < SUPERBLOCK_SIZE/2; check_idx++) {
 213                 if (old_super[check_idx] == new_super[check_idx])
 214                         continue;
 215                 write_idx = check_idx;
 216                 for (check_idx++; check_idx < SUPERBLOCK_SIZE/2; check_idx++)
 217                         if (old_super[check_idx] == new_super[check_idx])
 218                                 break;
 219                 size = 2 * (check_idx - write_idx);
 220 #if 0
 221                 printf("Writing %d bytes starting at %d\n",
 222                        size, write_idx*2);
 223 #endif
 224                 retval = io_channel_write_byte(fs->io,
 225                                SUPERBLOCK_OFFSET + (2 * write_idx), size,
 226                                                new_super + write_idx);
 227                 if (retval == EXT2_ET_UNIMPLEMENTED)
 228                         goto fallback;
 229                 if (retval)
 230                         return retval;
 231         }
 232         memcpy(fs->orig_super, super, SUPERBLOCK_SIZE);
 233         return 0;
 234 }
 235
 236
 237 /*
 238  * Updates the revision to EXT2_DYNAMIC_REV
 239  */
 240 void ext2fs_update_dynamic_rev(ext2_filsys fs)
 241 {
 242         struct ext2_super_block *sb = fs->super;
 243
 244         if (sb->s_rev_level > EXT2_GOOD_OLD_REV)
 245                 return;
 246
 247         sb->s_rev_level = EXT2_DYNAMIC_REV;
 248         sb->s_first_ino = EXT2_GOOD_OLD_FIRST_INO;
 249         sb->s_inode_size = EXT2_GOOD_OLD_INODE_SIZE;
 250         /* s_uuid is handled by e2fsck already */
 251         /* other fields should be left alone */
 252 }
 253
 254 static errcode_t write_backup_super(ext2_filsys fs, dgrp_t group,
 255                                     blk64_t group_block,
 256                                     struct ext2_super_block *super_shadow)
 257 {
 258         errcode_t retval;
 259         dgrp_t  sgrp = group;
 260
 261         if (sgrp > ((1 << 16) - 1))
 262                 sgrp = (1 << 16) - 1;
 263
 264         super_shadow->s_block_group_nr = sgrp;
 265 #ifdef WORDS_BIGENDIAN
 266         ext2fs_swap_super(super_shadow);
 267 #endif
 268         retval = ext2fs_superblock_csum_set(fs, super_shadow);
 269         if (retval)
 270                 return retval;
 271
 272         return io_channel_write_blk64(fs->io, group_block, -SUPERBLOCK_SIZE,
 273                                     super_shadow);
 274 }
 275
 276 errcode_t ext2fs_flush(ext2_filsys fs)
 277 {
 278         return ext2fs_flush2(fs, 0);
 279 }
 280
 281 errcode_t ext2fs_flush2(ext2_filsys fs, int flags)
 282 {
 283         dgrp_t          i;
 284         errcode_t       retval;
 285         unsigned long   fs_state;
 286         __u32           feature_incompat;
 287         struct ext2_super_block *super_shadow = 0;
 288         struct ext2_group_desc *group_shadow = 0;
 289 #ifdef WORDS_BIGENDIAN
 290         struct ext2_group_desc *gdp;
 291         dgrp_t          j;
 292 #endif
 293         char    *group_ptr;
 294         int     old_desc_blocks;
 295         struct ext2fs_numeric_progress_struct progress;
 296
 297         EXT2_CHECK_MAGIC(fs, EXT2_ET_MAGIC_EXT2FS_FILSYS);
 298
 299         fs_state = fs->super->s_state;
 300         feature_incompat = fs->super->s_feature_incompat;
 301
 302         fs->super->s_wtime = fs->now ? fs->now : time(NULL);
 303         fs->super->s_block_group_nr = 0;
 304
 305         /*
 306          * If the write_bitmaps() function is present, call it to
 307          * flush the bitmaps.  This is done this way so that a simple
 308          * program that doesn't mess with the bitmaps doesn't need to
 309          * drag in the bitmaps.c code.
 310          *
 311          * Bitmap checksums live in the group descriptor, so the
 312          * bitmaps need to be written before the descriptors.
 313          */
 314         if (fs->write_bitmaps) {
 315                 retval = fs->write_bitmaps(fs);
 316                 if (retval)
 317                         goto errout;
 318         }
 319
 320         /* Prepare the group descriptors for writing */
 321 #ifdef WORDS_BIGENDIAN
 322         retval = EXT2_ET_NO_MEMORY;
 323         retval = ext2fs_get_mem(SUPERBLOCK_SIZE, &super_shadow);
 324         if (retval)
 325                 goto errout;
 326         retval = ext2fs_get_array(fs->desc_blocks, fs->blocksize,
 327                                   &group_shadow);
 328         if (retval)
 329                 goto errout;
 330         memcpy(super_shadow, fs->super, sizeof(struct ext2_super_block));
 331         memcpy(group_shadow, fs->group_desc, (size_t) fs->blocksize *
 332                fs->desc_blocks);
 333
 334         /* swap the group descriptors */
 335         for (j = 0; j < fs->group_desc_count; j++) {
 336                 gdp = ext2fs_group_desc(fs, group_shadow, j);
 337                 ext2fs_swap_group_desc2(fs, gdp);
 338         }
 339 #else
 340         super_shadow = fs->super;
 341         group_shadow = ext2fs_group_desc(fs, fs->group_desc, 0);
 342 #endif
 343
 344         /*
 345          * Set the state of the FS to be non-valid.  (The state has
 346          * already been backed up earlier, and will be restored after
 347          * we write out the backup superblocks.)
 348          */
 349         fs->super->s_state &= ~EXT2_VALID_FS;
 350         fs->super->s_feature_incompat &= ~EXT3_FEATURE_INCOMPAT_RECOVER;
 351
 352         /*
 353          * If this is an external journal device, don't write out the
 354          * block group descriptors or any of the backup superblocks
 355          */
 356         if (fs->super->s_feature_incompat &
 357             EXT3_FEATURE_INCOMPAT_JOURNAL_DEV)
 358                 goto write_primary_superblock_only;
 359
 360         /*
 361          * Write out the master group descriptors, and the backup
 362          * superblocks and group descriptors.
 363          */
 364         group_ptr = (char *) group_shadow;
 365         if (fs->super->s_feature_incompat & EXT2_FEATURE_INCOMPAT_META_BG) {
 366                 old_desc_blocks = fs->super->s_first_meta_bg;
 367                 if (old_desc_blocks > fs->super->s_first_meta_bg)
 368                         old_desc_blocks = fs->desc_blocks;
 369         } else
 370                 old_desc_blocks = fs->desc_blocks;
 371
 372         if (fs->progress_ops && fs->progress_ops->init)
 373                 (fs->progress_ops->init)(fs, &progress, NULL,
 374                                          fs->group_desc_count);
 375
 376
 377         for (i = 0; i < fs->group_desc_count; i++) {
 378                 blk64_t super_blk, old_desc_blk, new_desc_blk;
 379
 380                 if (fs->progress_ops && fs->progress_ops->update)
 381                         (fs->progress_ops->update)(fs, &progress, i);
 382                 ext2fs_super_and_bgd_loc2(fs, i, &super_blk, &old_desc_blk,
 383                                          &new_desc_blk, 0);
 384
 385                 if (!(fs->flags & EXT2_FLAG_MASTER_SB_ONLY) &&i && super_blk) {
 386                         retval = write_backup_super(fs, i, super_blk,
 387                                                     super_shadow);
 388                         if (retval)
 389                                 goto errout;
 390                 }
 391                 if (fs->flags & EXT2_FLAG_SUPER_ONLY)
 392                         continue;
 393                 if ((old_desc_blk) &&
 394                     (!(fs->flags & EXT2_FLAG_MASTER_SB_ONLY) || (i == 0))) {
 395                         retval = io_channel_write_blk64(fs->io,
 396                               old_desc_blk, old_desc_blocks, group_ptr);
 397                         if (retval)
 398                                 goto errout;
 399                 }
 400                 if (new_desc_blk) {
 401                         int meta_bg = i / EXT2_DESC_PER_BLOCK(fs->super);
 402
 403                         retval = io_channel_write_blk64(fs->io, new_desc_blk,
 404                                 1, group_ptr + (meta_bg*fs->blocksize));
 405                         if (retval)
 406                                 goto errout;
 407                 }
 408         }
 409
 410         if (fs->progress_ops && fs->progress_ops->close)
 411                 (fs->progress_ops->close)(fs, &progress, NULL);
 412
 413 write_primary_superblock_only:
 414         /*
 415          * Write out master superblock.  This has to be done
 416          * separately, since it is located at a fixed location
 417          * (SUPERBLOCK_OFFSET).  We flush all other pending changes
 418          * out to disk first, just to avoid a race condition with an
 419          * insy-tinsy window....
 420          */
 421
 422         fs->super->s_block_group_nr = 0;
 423         fs->super->s_state = fs_state;
 424         fs->super->s_feature_incompat = feature_incompat;
 425 #ifdef WORDS_BIGENDIAN
 426         *super_shadow = *fs->super;
 427         ext2fs_swap_super(super_shadow);
 428 #endif
 429
 430         retval = ext2fs_superblock_csum_set(fs, super_shadow);
 431         if (retval)
 432                 return retval;
 433
 434         if (!(flags & EXT2_FLAG_FLUSH_NO_SYNC))
 435                 retval = io_channel_flush(fs->io);
 436         retval = write_primary_superblock(fs, super_shadow);
 437         if (retval)
 438                 goto errout;
 439
 440         fs->flags &= ~EXT2_FLAG_DIRTY;
 441
 442         if (!(flags & EXT2_FLAG_FLUSH_NO_SYNC))
 443                 retval = io_channel_flush(fs->io);
 444 errout:
 445         fs->super->s_state = fs_state;
 446 #ifdef WORDS_BIGENDIAN
 447         if (super_shadow)
 448                 ext2fs_free_mem(&super_shadow);
 449         if (group_shadow)
 450                 ext2fs_free_mem(&group_shadow);
 451 #endif
 452         return retval;
 453 }
 454
 455 errcode_t ext2fs_close_free(ext2_filsys *fs_ptr)
 456 {
 457         errcode_t ret;
 458         ext2_filsys fs = *fs_ptr;
 459
 460         ret = ext2fs_close2(fs, 0);
 461         if (ret)
 462                 ext2fs_free(fs);
 463         *fs_ptr = NULL;
 464         return ret;
 465 }
 466
 467 errcode_t ext2fs_close(ext2_filsys fs)
 468 {
 469         return ext2fs_close2(fs, 0);
 470 }
 471
 472 errcode_t ext2fs_close2(ext2_filsys fs, int flags)
 473 {
 474         errcode_t       retval;
 475         int             meta_blks;
 476         io_stats stats = 0;
 477
 478         EXT2_CHECK_MAGIC(fs, EXT2_ET_MAGIC_EXT2FS_FILSYS);
 479
 480         if (fs->write_bitmaps) {
 481                 retval = fs->write_bitmaps(fs);
 482                 if (retval)
 483                         return retval;
 484         }
 485         if (fs->super->s_kbytes_written &&
 486             fs->io->manager->get_stats)
 487                 fs->io->manager->get_stats(fs->io, &stats);
 488         if (stats && stats->bytes_written && (fs->flags & EXT2_FLAG_RW)) {
 489                 fs->super->s_kbytes_written += stats->bytes_written >> 10;
 490                 meta_blks = fs->desc_blocks + 1;
 491                 if (!(fs->flags & EXT2_FLAG_SUPER_ONLY))
 492                         fs->super->s_kbytes_written += meta_blks /
 493                                 (fs->blocksize / 1024);
 494                 if ((fs->flags & EXT2_FLAG_DIRTY) == 0)
 495                         fs->flags |= EXT2_FLAG_SUPER_ONLY | EXT2_FLAG_DIRTY;
 496         }
 497         if (fs->flags & EXT2_FLAG_DIRTY) {
 498                 retval = ext2fs_flush2(fs, flags);
 499                 if (retval)
 500                         return retval;
 501         }
 502
 503         retval = ext2fs_mmp_stop(fs);
 504         if (retval)
 505                 return retval;
 506
 507         ext2fs_free(fs);
 508         return 0;
 509 }
 510