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 (ext2fs_has_feature_sparse_super2(fs->super)) {
  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) || !ext2fs_has_feature_sparse_super(fs->super))
  47                 return 1;
  48         if (!(group & 1))
  49                 return 0;
  50         if (test_root(group, 3) || (test_root(group, 5)) ||
  51             test_root(group, 7))
  52                 return 1;
  53
  54         return 0;
  55 }
  56
  57 /*
  58  * ext2fs_super_and_bgd_loc2()
  59  * @fs:                 ext2 fs pointer
  60  * @group               given block group
  61  * @ret_super_blk:      if !NULL, returns super block location
  62  * @ret_old_desc_blk:   if !NULL, returns location of the old block
  63  *                      group descriptor
  64  * @ret_new_desc_blk:   if !NULL, returns location of meta_bg block
  65  *                      group descriptor
  66  * @ret_used_blks:      if !NULL, returns number of blocks used by
  67  *                      super block and group_descriptors.
  68  *
  69  * Returns errcode_t of 0
  70  */
  71 errcode_t ext2fs_super_and_bgd_loc2(ext2_filsys fs,
  72                                            dgrp_t group,
  73                                            blk64_t *ret_super_blk,
  74                                            blk64_t *ret_old_desc_blk,
  75                                            blk64_t *ret_new_desc_blk,
  76                                            blk_t *ret_used_blks)
  77 {
  78         blk64_t group_block, super_blk = 0, old_desc_blk = 0, new_desc_blk = 0;
  79         unsigned int meta_bg, meta_bg_size;
  80         blk_t   numblocks = 0;
  81         blk64_t old_desc_blocks;
  82         int     has_super;
  83
  84         group_block = ext2fs_group_first_block2(fs, group);
  85         if (group_block == 0 && fs->blocksize == 1024)
  86                 group_block = 1; /* Deal with 1024 blocksize && bigalloc */
  87
  88         if (ext2fs_has_feature_meta_bg(fs->super))
  89                 old_desc_blocks = fs->super->s_first_meta_bg;
  90         else
  91                 old_desc_blocks =
  92                         fs->desc_blocks + fs->super->s_reserved_gdt_blocks;
  93
  94         has_super = ext2fs_bg_has_super(fs, group);
  95
  96         if (has_super) {
  97                 super_blk = group_block;
  98                 numblocks++;
  99         }
 100         meta_bg_size = EXT2_DESC_PER_BLOCK(fs->super);
 101         meta_bg = group / meta_bg_size;
 102
 103         if (!ext2fs_has_feature_meta_bg(fs->super) ||
 104             (meta_bg < fs->super->s_first_meta_bg)) {
 105                 if (has_super) {
 106                         old_desc_blk = group_block + 1;
 107                         numblocks += old_desc_blocks;
 108                 }
 109         } else {
 110                 if (((group % meta_bg_size) == 0) ||
 111                     ((group % meta_bg_size) == 1) ||
 112                     ((group % meta_bg_size) == (meta_bg_size-1))) {
 113                         if (has_super)
 114                                 has_super = 1;
 115                         new_desc_blk = group_block + has_super;
 116                         numblocks++;
 117                 }
 118         }
 119
 120         if (ret_super_blk)
 121                 *ret_super_blk = super_blk;
 122         if (ret_old_desc_blk)
 123                 *ret_old_desc_blk = old_desc_blk;
 124         if (ret_new_desc_blk)
 125                 *ret_new_desc_blk = new_desc_blk;
 126         if (ret_used_blks)
 127                 *ret_used_blks = numblocks;
 128
 129         return 0;
 130 }
 131
 132 /*
 133  * This function returns the location of the superblock, block group
 134  * descriptors for a given block group.  It currently returns the
 135  * number of free blocks assuming that inode table and allocation
 136  * bitmaps will be in the group.  This is not necessarily the case
 137  * when the flex_bg feature is enabled, so callers should take care!
 138  * It was only really intended for use by mke2fs, and even there it's
 139  * not that useful.
 140  *
 141  * The ext2fs_super_and_bgd_loc2() function is 64-bit block number
 142  * capable and returns the number of blocks used by super block and
 143  * group descriptors.
 144  */
 145 int ext2fs_super_and_bgd_loc(ext2_filsys fs,
 146                              dgrp_t group,
 147                              blk_t *ret_super_blk,
 148                              blk_t *ret_old_desc_blk,
 149                              blk_t *ret_new_desc_blk,
 150                              int *ret_meta_bg)
 151 {
 152         blk64_t ret_super_blk2;
 153         blk64_t ret_old_desc_blk2;
 154         blk64_t ret_new_desc_blk2;
 155         blk_t ret_used_blks;
 156         blk_t numblocks;
 157         unsigned int meta_bg_size;
 158
 159         ext2fs_super_and_bgd_loc2(fs, group, &ret_super_blk2,
 160                                         &ret_old_desc_blk2,
 161                                         &ret_new_desc_blk2,
 162                                         &ret_used_blks);
 163
 164         numblocks = ext2fs_group_blocks_count(fs, group);
 165
 166         if (ret_super_blk)
 167                 *ret_super_blk = (blk_t)ret_super_blk2;
 168         if (ret_old_desc_blk)
 169                 *ret_old_desc_blk = (blk_t)ret_old_desc_blk2;
 170         if (ret_new_desc_blk)
 171                 *ret_new_desc_blk = (blk_t)ret_new_desc_blk2;
 172         if (ret_meta_bg) {
 173                 meta_bg_size = EXT2_DESC_PER_BLOCK(fs->super);
 174                 *ret_meta_bg = group / meta_bg_size;
 175         }
 176
 177         numblocks -= 2 + fs->inode_blocks_per_group + ret_used_blks;
 178
 179         return numblocks;
 180 }
 181
 182 /*
 183  * This function forces out the primary superblock.  We need to only
 184  * write out those fields which we have changed, since if the
 185  * filesystem is mounted, it may have changed some of the other
 186  * fields.
 187  *
 188  * It takes as input a superblock which has already been byte swapped
 189  * (if necessary).
 190  *
 191  */
 192 static errcode_t write_primary_superblock(ext2_filsys fs,
 193                                           struct ext2_super_block *super)
 194 {
 195         __u16           *old_super, *new_super;
 196         int             check_idx, write_idx, size;
 197         errcode_t       retval;
 198
 199         if (!fs->io->manager->write_byte || !fs->orig_super) {
 200         fallback:
 201                 io_channel_set_blksize(fs->io, SUPERBLOCK_OFFSET);
 202                 retval = io_channel_write_blk64(fs->io, 1, -SUPERBLOCK_SIZE,
 203                                               super);
 204                 io_channel_set_blksize(fs->io, fs->blocksize);
 205                 return retval;
 206         }
 207
 208         old_super = (__u16 *) fs->orig_super;
 209         new_super = (__u16 *) super;
 210
 211         for (check_idx = 0; check_idx < SUPERBLOCK_SIZE/2; check_idx++) {
 212                 if (old_super[check_idx] == new_super[check_idx])
 213                         continue;
 214                 write_idx = check_idx;
 215                 for (check_idx++; check_idx < SUPERBLOCK_SIZE/2; check_idx++)
 216                         if (old_super[check_idx] == new_super[check_idx])
 217                                 break;
 218                 size = 2 * (check_idx - write_idx);
 219 #if 0
 220                 printf("Writing %d bytes starting at %d\n",
 221                        size, write_idx*2);
 222 #endif
 223                 retval = io_channel_write_byte(fs->io,
 224                                SUPERBLOCK_OFFSET + (2 * write_idx), size,
 225                                                new_super + write_idx);
 226                 if (retval == EXT2_ET_UNIMPLEMENTED)
 227                         goto fallback;
 228                 if (retval)
 229                         return retval;
 230         }
 231         memcpy(fs->orig_super, super, SUPERBLOCK_SIZE);
 232         return 0;
 233 }
 234
 235
 236 /*
 237  * Updates the revision to EXT2_DYNAMIC_REV
 238  */
 239 void ext2fs_update_dynamic_rev(ext2_filsys fs)
 240 {
 241         struct ext2_super_block *sb = fs->super;
 242
 243         if (sb->s_rev_level > EXT2_GOOD_OLD_REV)
 244                 return;
 245
 246         sb->s_rev_level = EXT2_DYNAMIC_REV;
 247         sb->s_first_ino = EXT2_GOOD_OLD_FIRST_INO;
 248         sb->s_inode_size = EXT2_GOOD_OLD_INODE_SIZE;
 249         /* s_uuid is handled by e2fsck already */
 250         /* other fields should be left alone */
 251 }
 252
 253 static errcode_t write_backup_super(ext2_filsys fs, dgrp_t group,
 254                                     blk64_t group_block,
 255                                     struct ext2_super_block *super_shadow)
 256 {
 257         errcode_t retval;
 258         dgrp_t  sgrp = group;
 259
 260         if (sgrp > ((1 << 16) - 1))
 261                 sgrp = (1 << 16) - 1;
 262
 263         super_shadow->s_block_group_nr = ext2fs_cpu_to_le16(sgrp);
 264
 265         retval = ext2fs_superblock_csum_set(fs, super_shadow);
 266         if (retval)
 267                 return retval;
 268
 269         return io_channel_write_blk64(fs->io, group_block, -SUPERBLOCK_SIZE,
 270                                     super_shadow);
 271 }
 272
 273 errcode_t ext2fs_flush(ext2_filsys fs)
 274 {
 275         return ext2fs_flush2(fs, 0);
 276 }
 277
 278 errcode_t ext2fs_flush2(ext2_filsys fs, int flags)
 279 {
 280         dgrp_t          i;
 281         errcode_t       retval;
 282         unsigned long   fs_state;
 283         __u32           feature_incompat;
 284         struct ext2_super_block *super_shadow = 0;
 285         struct opaque_ext2_group_desc *group_shadow = 0;
 286 #ifdef WORDS_BIGENDIAN
 287         struct ext2_group_desc *gdp;
 288         dgrp_t          j;
 289 #endif
 290         char    *group_ptr;
 291         blk64_t old_desc_blocks;
 292         struct ext2fs_numeric_progress_struct progress;
 293
 294         EXT2_CHECK_MAGIC(fs, EXT2_ET_MAGIC_EXT2FS_FILSYS);
 295
 296         fs_state = fs->super->s_state;
 297         feature_incompat = fs->super->s_feature_incompat;
 298
 299         fs->super->s_wtime = fs->now ? fs->now : time(NULL);
 300         fs->super->s_block_group_nr = 0;
 301
 302         /*
 303          * If the write_bitmaps() function is present, call it to
 304          * flush the bitmaps.  This is done this way so that a simple
 305          * program that doesn't mess with the bitmaps doesn't need to
 306          * drag in the bitmaps.c code.
 307          *
 308          * Bitmap checksums live in the group descriptor, so the
 309          * bitmaps need to be written before the descriptors.
 310          */
 311         if (fs->write_bitmaps) {
 312                 retval = fs->write_bitmaps(fs);
 313                 if (retval)
 314                         goto errout;
 315         }
 316
 317         /*
 318          * Set the state of the FS to be non-valid.  (The state has
 319          * already been backed up earlier, and will be restored after
 320          * we write out the backup superblocks.)
 321          */
 322         fs->super->s_state &= ~EXT2_VALID_FS;
 323         ext2fs_clear_feature_journal_needs_recovery(fs->super);
 324
 325         /* Byte swap the superblock and the group descriptors if necessary */
 326 #ifdef WORDS_BIGENDIAN
 327         retval = EXT2_ET_NO_MEMORY;
 328         retval = ext2fs_get_mem(SUPERBLOCK_SIZE, &super_shadow);
 329         if (retval)
 330                 goto errout;
 331         retval = ext2fs_get_array(fs->desc_blocks, fs->blocksize,
 332                                   &group_shadow);
 333         if (retval)
 334                 goto errout;
 335         memcpy(super_shadow, fs->super, sizeof(struct ext2_super_block));
 336         memcpy(group_shadow, fs->group_desc, (size_t) fs->blocksize *
 337                fs->desc_blocks);
 338
 339         ext2fs_swap_super(super_shadow);
 340         for (j = 0; j < fs->group_desc_count; j++) {
 341                 gdp = ext2fs_group_desc(fs, group_shadow, j);
 342                 ext2fs_swap_group_desc2(fs, gdp);
 343         }
 344 #else
 345         super_shadow = fs->super;
 346         group_shadow = fs->group_desc;
 347 #endif
 348
 349         /*
 350          * If this is an external journal device, don't write out the
 351          * block group descriptors or any of the backup superblocks
 352          */
 353         if (ext2fs_has_feature_journal_dev(fs->super))
 354                 goto write_primary_superblock_only;
 355
 356         /*
 357          * Write out the master group descriptors, and the backup
 358          * superblocks and group descriptors.
 359          */
 360         group_ptr = (char *) group_shadow;
 361         if (ext2fs_has_feature_meta_bg(fs->super)) {
 362                 old_desc_blocks = fs->super->s_first_meta_bg;
 363                 if (old_desc_blocks > fs->desc_blocks)
 364                         old_desc_blocks = fs->desc_blocks;
 365         } else
 366                 old_desc_blocks = fs->desc_blocks;
 367
 368         if (fs->progress_ops && fs->progress_ops->init)
 369                 (fs->progress_ops->init)(fs, &progress, NULL,
 370                                          fs->group_desc_count);
 371
 372
 373         for (i = 0; i < fs->group_desc_count; i++) {
 374                 blk64_t super_blk, old_desc_blk, new_desc_blk;
 375
 376                 if (fs->progress_ops && fs->progress_ops->update)
 377                         (fs->progress_ops->update)(fs, &progress, i);
 378                 ext2fs_super_and_bgd_loc2(fs, i, &super_blk, &old_desc_blk,
 379                                          &new_desc_blk, 0);
 380
 381                 if (!(fs->flags & EXT2_FLAG_MASTER_SB_ONLY) &&i && super_blk) {
 382                         retval = write_backup_super(fs, i, super_blk,
 383                                                     super_shadow);
 384                         if (retval)
 385                                 goto errout;
 386                 }
 387                 if (fs->flags & EXT2_FLAG_SUPER_ONLY)
 388                         continue;
 389                 if ((old_desc_blk) &&
 390                     (!(fs->flags & EXT2_FLAG_MASTER_SB_ONLY) || (i == 0))) {
 391                         retval = io_channel_write_blk64(fs->io,
 392                               old_desc_blk, old_desc_blocks, group_ptr);
 393                         if (retval)
 394                                 goto errout;
 395                 }
 396                 if (new_desc_blk) {
 397                         int meta_bg = i / EXT2_DESC_PER_BLOCK(fs->super);
 398
 399                         retval = io_channel_write_blk64(fs->io, new_desc_blk,
 400                                 1, group_ptr + (meta_bg*fs->blocksize));
 401                         if (retval)
 402                                 goto errout;
 403                 }
 404         }
 405
 406         if (fs->progress_ops && fs->progress_ops->close)
 407                 (fs->progress_ops->close)(fs, &progress, NULL);
 408
 409 write_primary_superblock_only:
 410         /*
 411          * Write out master superblock.  This has to be done
 412          * separately, since it is located at a fixed location
 413          * (SUPERBLOCK_OFFSET).  We flush all other pending changes
 414          * out to disk first, just to avoid a race condition with an
 415          * insy-tinsy window....
 416          */
 417
 418         fs->super->s_block_group_nr = 0;
 419         fs->super->s_state = fs_state;
 420         fs->super->s_feature_incompat = feature_incompat;
 421 #ifdef WORDS_BIGENDIAN
 422         *super_shadow = *fs->super;
 423         ext2fs_swap_super(super_shadow);
 424 #endif
 425
 426         retval = ext2fs_superblock_csum_set(fs, super_shadow);
 427         if (retval)
 428                 return retval;
 429
 430         if (!(flags & EXT2_FLAG_FLUSH_NO_SYNC)) {
 431                 retval = io_channel_flush(fs->io);
 432                 if (retval)
 433                         goto errout;
 434         }
 435         retval = write_primary_superblock(fs, super_shadow);
 436         if (retval)
 437                 goto errout;
 438
 439         fs->flags &= ~EXT2_FLAG_DIRTY;
 440
 441         if (!(flags & EXT2_FLAG_FLUSH_NO_SYNC)) {
 442                 retval = io_channel_flush(fs->io);
 443                 if (retval)
 444                         goto errout;
 445         }
 446 errout:
 447         fs->super->s_state = fs_state;
 448 #ifdef WORDS_BIGENDIAN
 449         if (super_shadow)
 450                 ext2fs_free_mem(&super_shadow);
 451         if (group_shadow)
 452                 ext2fs_free_mem(&group_shadow);
 453 #endif
 454         return retval;
 455 }
 456
 457 errcode_t ext2fs_close_free(ext2_filsys *fs_ptr)
 458 {
 459         errcode_t ret;
 460         ext2_filsys fs = *fs_ptr;
 461
 462         ret = ext2fs_close2(fs, 0);
 463         if (ret)
 464                 ext2fs_free(fs);
 465         *fs_ptr = NULL;
 466         return ret;
 467 }
 468
 469 errcode_t ext2fs_close(ext2_filsys fs)
 470 {
 471         return ext2fs_close2(fs, 0);
 472 }
 473
 474 errcode_t ext2fs_close2(ext2_filsys fs, int flags)
 475 {
 476         errcode_t       retval;
 477         int             meta_blks;
 478         io_stats stats = 0;
 479
 480         EXT2_CHECK_MAGIC(fs, EXT2_ET_MAGIC_EXT2FS_FILSYS);
 481
 482         if (fs->write_bitmaps) {
 483                 retval = fs->write_bitmaps(fs);
 484                 if (retval)
 485                         return retval;
 486         }
 487         if (fs->super->s_kbytes_written &&
 488             fs->io->manager->get_stats)
 489                 fs->io->manager->get_stats(fs->io, &stats);
 490         if (stats && stats->bytes_written && (fs->flags & EXT2_FLAG_RW)) {
 491                 fs->super->s_kbytes_written += stats->bytes_written >> 10;
 492                 meta_blks = fs->desc_blocks + 1;
 493                 if (!(fs->flags & EXT2_FLAG_SUPER_ONLY))
 494                         fs->super->s_kbytes_written += meta_blks /
 495                                 (fs->blocksize / 1024);
 496                 if ((fs->flags & EXT2_FLAG_DIRTY) == 0)
 497                         fs->flags |= EXT2_FLAG_SUPER_ONLY | EXT2_FLAG_DIRTY;
 498         }
 499         if (fs->flags & EXT2_FLAG_DIRTY) {
 500                 retval = ext2fs_flush2(fs, flags);
 501                 if (retval)
 502                         return retval;
 503         }
 504
 505         retval = ext2fs_mmp_stop(fs);
 506         if (retval)
 507                 return retval;
 508
 509         ext2fs_free(fs);
 510         return 0;
 511 }
 512