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 = sgrp;
 264 #ifdef WORDS_BIGENDIAN
 265         ext2fs_swap_super(super_shadow);
 266 #endif
 267         retval = ext2fs_superblock_csum_set(fs, super_shadow);
 268         if (retval)
 269                 return retval;
 270
 271         return io_channel_write_blk64(fs->io, group_block, -SUPERBLOCK_SIZE,
 272                                     super_shadow);
 273 }
 274
 275 errcode_t ext2fs_flush(ext2_filsys fs)
 276 {
 277         return ext2fs_flush2(fs, 0);
 278 }
 279
 280 errcode_t ext2fs_flush2(ext2_filsys fs, int flags)
 281 {
 282         dgrp_t          i;
 283         errcode_t       retval;
 284         unsigned long   fs_state;
 285         __u32           feature_incompat;
 286         struct ext2_super_block *super_shadow = 0;
 287         struct ext2_group_desc *group_shadow = 0;
 288 #ifdef WORDS_BIGENDIAN
 289         struct ext2_group_desc *gdp;
 290         dgrp_t          j;
 291 #endif
 292         char    *group_ptr;
 293         blk64_t old_desc_blocks;
 294         struct ext2fs_numeric_progress_struct progress;
 295
 296         EXT2_CHECK_MAGIC(fs, EXT2_ET_MAGIC_EXT2FS_FILSYS);
 297
 298         fs_state = fs->super->s_state;
 299         feature_incompat = fs->super->s_feature_incompat;
 300
 301         fs->super->s_wtime = fs->now ? fs->now : time(NULL);
 302         fs->super->s_block_group_nr = 0;
 303
 304         /*
 305          * If the write_bitmaps() function is present, call it to
 306          * flush the bitmaps.  This is done this way so that a simple
 307          * program that doesn't mess with the bitmaps doesn't need to
 308          * drag in the bitmaps.c code.
 309          *
 310          * Bitmap checksums live in the group descriptor, so the
 311          * bitmaps need to be written before the descriptors.
 312          */
 313         if (fs->write_bitmaps) {
 314                 retval = fs->write_bitmaps(fs);
 315                 if (retval)
 316                         goto errout;
 317         }
 318
 319         /* Prepare the group descriptors for writing */
 320 #ifdef WORDS_BIGENDIAN
 321         retval = EXT2_ET_NO_MEMORY;
 322         retval = ext2fs_get_mem(SUPERBLOCK_SIZE, &super_shadow);
 323         if (retval)
 324                 goto errout;
 325         retval = ext2fs_get_array(fs->desc_blocks, fs->blocksize,
 326                                   &group_shadow);
 327         if (retval)
 328                 goto errout;
 329         memcpy(super_shadow, fs->super, sizeof(struct ext2_super_block));
 330         memcpy(group_shadow, fs->group_desc, (size_t) fs->blocksize *
 331                fs->desc_blocks);
 332
 333         /* swap the group descriptors */
 334         for (j = 0; j < fs->group_desc_count; j++) {
 335                 gdp = ext2fs_group_desc(fs, group_shadow, j);
 336                 ext2fs_swap_group_desc2(fs, gdp);
 337         }
 338 #else
 339         super_shadow = fs->super;
 340         group_shadow = ext2fs_group_desc(fs, fs->group_desc, 0);
 341 #endif
 342
 343         /*
 344          * Set the state of the FS to be non-valid.  (The state has
 345          * already been backed up earlier, and will be restored after
 346          * we write out the backup superblocks.)
 347          */
 348         fs->super->s_state &= ~EXT2_VALID_FS;
 349         ext2fs_clear_feature_journal_needs_recovery(fs->super);
 350
 351         /*
 352          * If this is an external journal device, don't write out the
 353          * block group descriptors or any of the backup superblocks
 354          */
 355         if (ext2fs_has_feature_journal_dev(fs->super))
 356                 goto write_primary_superblock_only;
 357
 358         /*
 359          * Write out the master group descriptors, and the backup
 360          * superblocks and group descriptors.
 361          */
 362         group_ptr = (char *) group_shadow;
 363         if (ext2fs_has_feature_meta_bg(fs->super)) {
 364                 old_desc_blocks = fs->super->s_first_meta_bg;
 365                 if (old_desc_blocks > fs->desc_blocks)
 366                         old_desc_blocks = fs->desc_blocks;
 367         } else
 368                 old_desc_blocks = fs->desc_blocks;
 369
 370         if (fs->progress_ops && fs->progress_ops->init)
 371                 (fs->progress_ops->init)(fs, &progress, NULL,
 372                                          fs->group_desc_count);
 373
 374
 375         for (i = 0; i < fs->group_desc_count; i++) {
 376                 blk64_t super_blk, old_desc_blk, new_desc_blk;
 377
 378                 if (fs->progress_ops && fs->progress_ops->update)
 379                         (fs->progress_ops->update)(fs, &progress, i);
 380                 ext2fs_super_and_bgd_loc2(fs, i, &super_blk, &old_desc_blk,
 381                                          &new_desc_blk, 0);
 382
 383                 if (!(fs->flags & EXT2_FLAG_MASTER_SB_ONLY) &&i && super_blk) {
 384                         retval = write_backup_super(fs, i, super_blk,
 385                                                     super_shadow);
 386                         if (retval)
 387                                 goto errout;
 388                 }
 389                 if (fs->flags & EXT2_FLAG_SUPER_ONLY)
 390                         continue;
 391                 if ((old_desc_blk) &&
 392                     (!(fs->flags & EXT2_FLAG_MASTER_SB_ONLY) || (i == 0))) {
 393                         retval = io_channel_write_blk64(fs->io,
 394                               old_desc_blk, old_desc_blocks, group_ptr);
 395                         if (retval)
 396                                 goto errout;
 397                 }
 398                 if (new_desc_blk) {
 399                         int meta_bg = i / EXT2_DESC_PER_BLOCK(fs->super);
 400
 401                         retval = io_channel_write_blk64(fs->io, new_desc_blk,
 402                                 1, group_ptr + (meta_bg*fs->blocksize));
 403                         if (retval)
 404                                 goto errout;
 405                 }
 406         }
 407
 408         if (fs->progress_ops && fs->progress_ops->close)
 409                 (fs->progress_ops->close)(fs, &progress, NULL);
 410
 411 write_primary_superblock_only:
 412         /*
 413          * Write out master superblock.  This has to be done
 414          * separately, since it is located at a fixed location
 415          * (SUPERBLOCK_OFFSET).  We flush all other pending changes
 416          * out to disk first, just to avoid a race condition with an
 417          * insy-tinsy window....
 418          */
 419
 420         fs->super->s_block_group_nr = 0;
 421         fs->super->s_state = fs_state;
 422         fs->super->s_feature_incompat = feature_incompat;
 423 #ifdef WORDS_BIGENDIAN
 424         *super_shadow = *fs->super;
 425         ext2fs_swap_super(super_shadow);
 426 #endif
 427
 428         retval = ext2fs_superblock_csum_set(fs, super_shadow);
 429         if (retval)
 430                 return retval;
 431
 432         if (!(flags & EXT2_FLAG_FLUSH_NO_SYNC))
 433                 retval = io_channel_flush(fs->io);
 434         retval = write_primary_superblock(fs, super_shadow);
 435         if (retval)
 436                 goto errout;
 437
 438         fs->flags &= ~EXT2_FLAG_DIRTY;
 439
 440         if (!(flags & EXT2_FLAG_FLUSH_NO_SYNC))
 441                 retval = io_channel_flush(fs->io);
 442 errout:
 443         fs->super->s_state = fs_state;
 444 #ifdef WORDS_BIGENDIAN
 445         if (super_shadow)
 446                 ext2fs_free_mem(&super_shadow);
 447         if (group_shadow)
 448                 ext2fs_free_mem(&group_shadow);
 449 #endif
 450         return retval;
 451 }
 452
 453 errcode_t ext2fs_close_free(ext2_filsys *fs_ptr)
 454 {
 455         errcode_t ret;
 456         ext2_filsys fs = *fs_ptr;
 457
 458         ret = ext2fs_close2(fs, 0);
 459         if (ret)
 460                 ext2fs_free(fs);
 461         *fs_ptr = NULL;
 462         return ret;
 463 }
 464
 465 errcode_t ext2fs_close(ext2_filsys fs)
 466 {
 467         return ext2fs_close2(fs, 0);
 468 }
 469
 470 errcode_t ext2fs_close2(ext2_filsys fs, int flags)
 471 {
 472         errcode_t       retval;
 473         int             meta_blks;
 474         io_stats stats = 0;
 475
 476         EXT2_CHECK_MAGIC(fs, EXT2_ET_MAGIC_EXT2FS_FILSYS);
 477
 478         if (fs->write_bitmaps) {
 479                 retval = fs->write_bitmaps(fs);
 480                 if (retval)
 481                         return retval;
 482         }
 483         if (fs->super->s_kbytes_written &&
 484             fs->io->manager->get_stats)
 485                 fs->io->manager->get_stats(fs->io, &stats);
 486         if (stats && stats->bytes_written && (fs->flags & EXT2_FLAG_RW)) {
 487                 fs->super->s_kbytes_written += stats->bytes_written >> 10;
 488                 meta_blks = fs->desc_blocks + 1;
 489                 if (!(fs->flags & EXT2_FLAG_SUPER_ONLY))
 490                         fs->super->s_kbytes_written += meta_blks /
 491                                 (fs->blocksize / 1024);
 492                 if ((fs->flags & EXT2_FLAG_DIRTY) == 0)
 493                         fs->flags |= EXT2_FLAG_SUPER_ONLY | EXT2_FLAG_DIRTY;
 494         }
 495         if (fs->flags & EXT2_FLAG_DIRTY) {
 496                 retval = ext2fs_flush2(fs, flags);
 497                 if (retval)
 498                         return retval;
 499         }
 500
 501         retval = ext2fs_mmp_stop(fs);
 502         if (retval)
 503                 return retval;
 504
 505         ext2fs_free(fs);
 506         return 0;
 507 }
 508