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(int a, int b)
  24 {
  25         if (a == 0)
  26                 return 1;
  27         while (1) {
  28                 if (a == 1)
  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, int group_block)
  37 {
  38         if (!(fs->super->s_feature_ro_compat &
  39               EXT2_FEATURE_RO_COMPAT_SPARSE_SUPER))
  40                 return 1;
  41
  42         if (test_root(group_block, 3) || (test_root(group_block, 5)) ||
  43             test_root(group_block, 7))
  44                 return 1;
  45
  46         return 0;
  47 }
  48
  49 /*
  50  * ext2fs_super_and_bgd_loc2()
  51  * @fs:                 ext2 fs pointer
  52  * @group               given block group
  53  * @ret_super_blk:      if !NULL, returns super block location
  54  * @ret_old_desc_blk:   if !NULL, returns location of the old block
  55  *                      group descriptor
  56  * @ret_new_desc_blk:   if !NULL, returns location of meta_bg block
  57  *                      group descriptor
  58  * @ret_used_blks:      if !NULL, returns number of blocks used by
  59  *                      super block and group_descriptors.
  60  *
  61  * Returns errcode_t of 0
  62  */
  63 errcode_t ext2fs_super_and_bgd_loc2(ext2_filsys fs,
  64                                            dgrp_t group,
  65                                            blk64_t *ret_super_blk,
  66                                            blk64_t *ret_old_desc_blk,
  67                                            blk64_t *ret_new_desc_blk,
  68                                            blk_t *ret_used_blks)
  69 {
  70         blk64_t group_block, super_blk = 0, old_desc_blk = 0, new_desc_blk = 0;
  71         unsigned int meta_bg, meta_bg_size;
  72         blk_t   numblocks = 0;
  73         blk64_t old_desc_blocks;
  74         int     has_super;
  75
  76         group_block = ext2fs_group_first_block2(fs, group);
  77         if (group_block == 0 && fs->blocksize == 1024)
  78                 group_block = 1; /* Deal with 1024 blocksize && bigalloc */
  79
  80         if (fs->super->s_feature_incompat & EXT2_FEATURE_INCOMPAT_META_BG)
  81                 old_desc_blocks = fs->super->s_first_meta_bg;
  82         else
  83                 old_desc_blocks =
  84                         fs->desc_blocks + fs->super->s_reserved_gdt_blocks;
  85
  86         has_super = ext2fs_bg_has_super(fs, group);
  87
  88         if (has_super) {
  89                 super_blk = group_block;
  90                 numblocks++;
  91         }
  92         meta_bg_size = EXT2_DESC_PER_BLOCK(fs->super);
  93         meta_bg = group / meta_bg_size;
  94
  95         if (!(fs->super->s_feature_incompat & EXT2_FEATURE_INCOMPAT_META_BG) ||
  96             (meta_bg < fs->super->s_first_meta_bg)) {
  97                 if (has_super) {
  98                         old_desc_blk = group_block + 1;
  99                         numblocks += old_desc_blocks;
 100                 }
 101         } else {
 102                 if (((group % meta_bg_size) == 0) ||
 103                     ((group % meta_bg_size) == 1) ||
 104                     ((group % meta_bg_size) == (meta_bg_size-1))) {
 105                         if (has_super)
 106                                 has_super = 1;
 107                         new_desc_blk = group_block + has_super;
 108                         numblocks++;
 109                 }
 110         }
 111
 112         if (ret_super_blk)
 113                 *ret_super_blk = super_blk;
 114         if (ret_old_desc_blk)
 115                 *ret_old_desc_blk = old_desc_blk;
 116         if (ret_new_desc_blk)
 117                 *ret_new_desc_blk = new_desc_blk;
 118         if (ret_used_blks)
 119                 *ret_used_blks = numblocks;
 120
 121         return 0;
 122 }
 123
 124 /*
 125  * This function returns the location of the superblock, block group
 126  * descriptors for a given block group.  It currently returns the
 127  * number of free blocks assuming that inode table and allocation
 128  * bitmaps will be in the group.  This is not necessarily the case
 129  * when the flex_bg feature is enabled, so callers should take care!
 130  * It was only really intended for use by mke2fs, and even there it's
 131  * not that useful.
 132  *
 133  * The ext2fs_super_and_bgd_loc2() function is 64-bit block number
 134  * capable and returns the number of blocks used by super block and
 135  * group descriptors.
 136  */
 137 int ext2fs_super_and_bgd_loc(ext2_filsys fs,
 138                              dgrp_t group,
 139                              blk_t *ret_super_blk,
 140                              blk_t *ret_old_desc_blk,
 141                              blk_t *ret_new_desc_blk,
 142                              int *ret_meta_bg)
 143 {
 144         blk64_t ret_super_blk2;
 145         blk64_t ret_old_desc_blk2;
 146         blk64_t ret_new_desc_blk2;
 147         blk_t ret_used_blks;
 148         blk_t numblocks;
 149         unsigned int meta_bg_size;
 150
 151         ext2fs_super_and_bgd_loc2(fs, group, &ret_super_blk2,
 152                                         &ret_old_desc_blk2,
 153                                         &ret_new_desc_blk2,
 154                                         &ret_used_blks);
 155
 156         numblocks = ext2fs_group_blocks_count(fs, group);
 157
 158         if (ret_super_blk)
 159                 *ret_super_blk = (blk_t)ret_super_blk2;
 160         if (ret_old_desc_blk)
 161                 *ret_old_desc_blk = (blk_t)ret_old_desc_blk2;
 162         if (ret_new_desc_blk)
 163                 *ret_new_desc_blk = (blk_t)ret_new_desc_blk2;
 164         if (ret_meta_bg) {
 165                 meta_bg_size = EXT2_DESC_PER_BLOCK(fs->super);
 166                 *ret_meta_bg = group / meta_bg_size;
 167         }
 168
 169         numblocks -= 2 + fs->inode_blocks_per_group + ret_used_blks;
 170
 171         return numblocks;
 172 }
 173
 174 /*
 175  * This function forces out the primary superblock.  We need to only
 176  * write out those fields which we have changed, since if the
 177  * filesystem is mounted, it may have changed some of the other
 178  * fields.
 179  *
 180  * It takes as input a superblock which has already been byte swapped
 181  * (if necessary).
 182  *
 183  */
 184 static errcode_t write_primary_superblock(ext2_filsys fs,
 185                                           struct ext2_super_block *super)
 186 {
 187         __u16           *old_super, *new_super;
 188         int             check_idx, write_idx, size;
 189         errcode_t       retval;
 190
 191         if (!fs->io->manager->write_byte || !fs->orig_super) {
 192         fallback:
 193                 io_channel_set_blksize(fs->io, SUPERBLOCK_OFFSET);
 194                 retval = io_channel_write_blk64(fs->io, 1, -SUPERBLOCK_SIZE,
 195                                               super);
 196                 io_channel_set_blksize(fs->io, fs->blocksize);
 197                 return retval;
 198         }
 199
 200         old_super = (__u16 *) fs->orig_super;
 201         new_super = (__u16 *) super;
 202
 203         for (check_idx = 0; check_idx < SUPERBLOCK_SIZE/2; check_idx++) {
 204                 if (old_super[check_idx] == new_super[check_idx])
 205                         continue;
 206                 write_idx = check_idx;
 207                 for (check_idx++; check_idx < SUPERBLOCK_SIZE/2; check_idx++)
 208                         if (old_super[check_idx] == new_super[check_idx])
 209                                 break;
 210                 size = 2 * (check_idx - write_idx);
 211 #if 0
 212                 printf("Writing %d bytes starting at %d\n",
 213                        size, write_idx*2);
 214 #endif
 215                 retval = io_channel_write_byte(fs->io,
 216                                SUPERBLOCK_OFFSET + (2 * write_idx), size,
 217                                                new_super + write_idx);
 218                 if (retval == EXT2_ET_UNIMPLEMENTED)
 219                         goto fallback;
 220                 if (retval)
 221                         return retval;
 222         }
 223         memcpy(fs->orig_super, super, SUPERBLOCK_SIZE);
 224         return 0;
 225 }
 226
 227
 228 /*
 229  * Updates the revision to EXT2_DYNAMIC_REV
 230  */
 231 void ext2fs_update_dynamic_rev(ext2_filsys fs)
 232 {
 233         struct ext2_super_block *sb = fs->super;
 234
 235         if (sb->s_rev_level > EXT2_GOOD_OLD_REV)
 236                 return;
 237
 238         sb->s_rev_level = EXT2_DYNAMIC_REV;
 239         sb->s_first_ino = EXT2_GOOD_OLD_FIRST_INO;
 240         sb->s_inode_size = EXT2_GOOD_OLD_INODE_SIZE;
 241         /* s_uuid is handled by e2fsck already */
 242         /* other fields should be left alone */
 243 }
 244
 245 static errcode_t write_backup_super(ext2_filsys fs, dgrp_t group,
 246                                     blk_t group_block,
 247                                     struct ext2_super_block *super_shadow)
 248 {
 249         dgrp_t  sgrp = group;
 250
 251         if (sgrp > ((1 << 16) - 1))
 252                 sgrp = (1 << 16) - 1;
 253 #ifdef WORDS_BIGENDIAN
 254         super_shadow->s_block_group_nr = ext2fs_swab16(sgrp);
 255 #else
 256         fs->super->s_block_group_nr = sgrp;
 257 #endif
 258
 259         return io_channel_write_blk64(fs->io, group_block, -SUPERBLOCK_SIZE,
 260                                     super_shadow);
 261 }
 262
 263 errcode_t ext2fs_flush(ext2_filsys fs)
 264 {
 265         return ext2fs_flush2(fs, 0);
 266 }
 267
 268 errcode_t ext2fs_flush2(ext2_filsys fs, int flags)
 269 {
 270         dgrp_t          i;
 271         errcode_t       retval;
 272         unsigned long   fs_state;
 273         __u32           feature_incompat;
 274         struct ext2_super_block *super_shadow = 0;
 275         struct ext2_group_desc *group_shadow = 0;
 276 #ifdef WORDS_BIGENDIAN
 277         struct ext2_group_desc *gdp;
 278         dgrp_t          j;
 279 #endif
 280         char    *group_ptr;
 281         int     old_desc_blocks;
 282         struct ext2fs_numeric_progress_struct progress;
 283
 284         EXT2_CHECK_MAGIC(fs, EXT2_ET_MAGIC_EXT2FS_FILSYS);
 285
 286         fs_state = fs->super->s_state;
 287         feature_incompat = fs->super->s_feature_incompat;
 288
 289         fs->super->s_wtime = fs->now ? fs->now : time(NULL);
 290         fs->super->s_block_group_nr = 0;
 291 #ifdef WORDS_BIGENDIAN
 292         retval = EXT2_ET_NO_MEMORY;
 293         retval = ext2fs_get_mem(SUPERBLOCK_SIZE, &super_shadow);
 294         if (retval)
 295                 goto errout;
 296         retval = ext2fs_get_array(fs->desc_blocks, fs->blocksize,
 297                                   &group_shadow);
 298         if (retval)
 299                 goto errout;
 300         memcpy(group_shadow, fs->group_desc, (size_t) fs->blocksize *
 301                fs->desc_blocks);
 302
 303         /* swap the group descriptors */
 304         for (j=0; j < fs->group_desc_count; j++) {
 305                 gdp = ext2fs_group_desc(fs, group_shadow, j);
 306                 ext2fs_swap_group_desc2(fs, gdp);
 307         }
 308 #else
 309         super_shadow = fs->super;
 310         group_shadow = ext2fs_group_desc(fs, fs->group_desc, 0);
 311 #endif
 312
 313         /*
 314          * Set the state of the FS to be non-valid.  (The state has
 315          * already been backed up earlier, and will be restored after
 316          * we write out the backup superblocks.)
 317          */
 318         fs->super->s_state &= ~EXT2_VALID_FS;
 319         fs->super->s_feature_incompat &= ~EXT3_FEATURE_INCOMPAT_RECOVER;
 320 #ifdef WORDS_BIGENDIAN
 321         *super_shadow = *fs->super;
 322         ext2fs_swap_super(super_shadow);
 323 #endif
 324
 325         /*
 326          * If this is an external journal device, don't write out the
 327          * block group descriptors or any of the backup superblocks
 328          */
 329         if (fs->super->s_feature_incompat &
 330             EXT3_FEATURE_INCOMPAT_JOURNAL_DEV)
 331                 goto write_primary_superblock_only;
 332
 333         /*
 334          * Write out the master group descriptors, and the backup
 335          * superblocks and group descriptors.
 336          */
 337         group_ptr = (char *) group_shadow;
 338         if (fs->super->s_feature_incompat & EXT2_FEATURE_INCOMPAT_META_BG)
 339                 old_desc_blocks = fs->super->s_first_meta_bg;
 340         else
 341                 old_desc_blocks = fs->desc_blocks;
 342
 343         ext2fs_numeric_progress_init(fs, &progress, NULL,
 344                                      fs->group_desc_count);
 345
 346
 347         for (i = 0; i < fs->group_desc_count; i++) {
 348                 blk64_t super_blk, old_desc_blk, new_desc_blk;
 349
 350                 ext2fs_numeric_progress_update(fs, &progress, i);
 351                 ext2fs_super_and_bgd_loc2(fs, i, &super_blk, &old_desc_blk,
 352                                          &new_desc_blk, 0);
 353
 354                 if (!(fs->flags & EXT2_FLAG_MASTER_SB_ONLY) &&i && super_blk) {
 355                         retval = write_backup_super(fs, i, super_blk,
 356                                                     super_shadow);
 357                         if (retval)
 358                                 goto errout;
 359                 }
 360                 if (fs->flags & EXT2_FLAG_SUPER_ONLY)
 361                         continue;
 362                 if ((old_desc_blk) &&
 363                     (!(fs->flags & EXT2_FLAG_MASTER_SB_ONLY) || (i == 0))) {
 364                         retval = io_channel_write_blk64(fs->io,
 365                               old_desc_blk, old_desc_blocks, group_ptr);
 366                         if (retval)
 367                                 goto errout;
 368                 }
 369                 if (new_desc_blk) {
 370                         int meta_bg = i / EXT2_DESC_PER_BLOCK(fs->super);
 371
 372                         retval = io_channel_write_blk64(fs->io, new_desc_blk,
 373                                 1, group_ptr + (meta_bg*fs->blocksize));
 374                         if (retval)
 375                                 goto errout;
 376                 }
 377         }
 378
 379         ext2fs_numeric_progress_close(fs, &progress, NULL);
 380
 381         /*
 382          * If the write_bitmaps() function is present, call it to
 383          * flush the bitmaps.  This is done this way so that a simple
 384          * program that doesn't mess with the bitmaps doesn't need to
 385          * drag in the bitmaps.c code.
 386          */
 387         if (fs->write_bitmaps) {
 388                 retval = fs->write_bitmaps(fs);
 389                 if (retval)
 390                         goto errout;
 391         }
 392
 393 write_primary_superblock_only:
 394         /*
 395          * Write out master superblock.  This has to be done
 396          * separately, since it is located at a fixed location
 397          * (SUPERBLOCK_OFFSET).  We flush all other pending changes
 398          * out to disk first, just to avoid a race condition with an
 399          * insy-tinsy window....
 400          */
 401
 402         fs->super->s_block_group_nr = 0;
 403         fs->super->s_state = fs_state;
 404         fs->super->s_feature_incompat = feature_incompat;
 405 #ifdef WORDS_BIGENDIAN
 406         *super_shadow = *fs->super;
 407         ext2fs_swap_super(super_shadow);
 408 #endif
 409
 410         if (!(flags & EXT2_FLAG_FLUSH_NO_SYNC))
 411                 retval = io_channel_flush(fs->io);
 412         retval = write_primary_superblock(fs, super_shadow);
 413         if (retval)
 414                 goto errout;
 415
 416         fs->flags &= ~EXT2_FLAG_DIRTY;
 417
 418         if (!(flags & EXT2_FLAG_FLUSH_NO_SYNC))
 419                 retval = io_channel_flush(fs->io);
 420 errout:
 421         fs->super->s_state = fs_state;
 422 #ifdef WORDS_BIGENDIAN
 423         if (super_shadow)
 424                 ext2fs_free_mem(&super_shadow);
 425         if (group_shadow)
 426                 ext2fs_free_mem(&group_shadow);
 427 #endif
 428         return retval;
 429 }
 430
 431 errcode_t ext2fs_close(ext2_filsys fs)
 432 {
 433         return ext2fs_close2(fs, 0);
 434 }
 435
 436 errcode_t ext2fs_close2(ext2_filsys fs, int flags)
 437 {
 438         errcode_t       retval;
 439         int             meta_blks;
 440         io_stats stats = 0;
 441
 442         EXT2_CHECK_MAGIC(fs, EXT2_ET_MAGIC_EXT2FS_FILSYS);
 443
 444         if (fs->write_bitmaps) {
 445                 retval = fs->write_bitmaps(fs);
 446                 if (retval)
 447                         return retval;
 448         }
 449         if (fs->super->s_kbytes_written &&
 450             fs->io->manager->get_stats)
 451                 fs->io->manager->get_stats(fs->io, &stats);
 452         if (stats && stats->bytes_written && (fs->flags & EXT2_FLAG_RW)) {
 453                 fs->super->s_kbytes_written += stats->bytes_written >> 10;
 454                 meta_blks = fs->desc_blocks + 1;
 455                 if (!(fs->flags & EXT2_FLAG_SUPER_ONLY))
 456                         fs->super->s_kbytes_written += meta_blks /
 457                                 (fs->blocksize / 1024);
 458                 if ((fs->flags & EXT2_FLAG_DIRTY) == 0)
 459                         fs->flags |= EXT2_FLAG_SUPER_ONLY | EXT2_FLAG_DIRTY;
 460         }
 461         if (fs->flags & EXT2_FLAG_DIRTY) {
 462                 retval = ext2fs_flush2(fs, flags);
 463                 if (retval)
 464                         return retval;
 465         }
 466         ext2fs_free(fs);
 467         return 0;
 468 }
 469