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 (!(fs->super->s_feature_ro_compat &
  39               EXT2_FEATURE_RO_COMPAT_SPARSE_SUPER) || group <= 1)
  40                 return 1;
  41         if (!(group & 1))
  42                 return 0;
  43         if (test_root(group, 3) || (test_root(group, 5)) ||
  44             test_root(group, 7))
  45                 return 1;
  46
  47         return 0;
  48 }
  49
  50 /*
  51  * ext2fs_super_and_bgd_loc2()
  52  * @fs:                 ext2 fs pointer
  53  * @group               given block group
  54  * @ret_super_blk:      if !NULL, returns super block location
  55  * @ret_old_desc_blk:   if !NULL, returns location of the old block
  56  *                      group descriptor
  57  * @ret_new_desc_blk:   if !NULL, returns location of meta_bg block
  58  *                      group descriptor
  59  * @ret_used_blks:      if !NULL, returns number of blocks used by
  60  *                      super block and group_descriptors.
  61  *
  62  * Returns errcode_t of 0
  63  */
  64 errcode_t ext2fs_super_and_bgd_loc2(ext2_filsys fs,
  65                                            dgrp_t group,
  66                                            blk64_t *ret_super_blk,
  67                                            blk64_t *ret_old_desc_blk,
  68                                            blk64_t *ret_new_desc_blk,
  69                                            blk_t *ret_used_blks)
  70 {
  71         blk64_t group_block, super_blk = 0, old_desc_blk = 0, new_desc_blk = 0;
  72         unsigned int meta_bg, meta_bg_size;
  73         blk_t   numblocks = 0;
  74         blk64_t old_desc_blocks;
  75         int     has_super;
  76
  77         group_block = ext2fs_group_first_block2(fs, group);
  78         if (group_block == 0 && fs->blocksize == 1024)
  79                 group_block = 1; /* Deal with 1024 blocksize && bigalloc */
  80
  81         if (fs->super->s_feature_incompat & EXT2_FEATURE_INCOMPAT_META_BG)
  82                 old_desc_blocks = fs->super->s_first_meta_bg;
  83         else
  84                 old_desc_blocks =
  85                         fs->desc_blocks + fs->super->s_reserved_gdt_blocks;
  86
  87         has_super = ext2fs_bg_has_super(fs, group);
  88
  89         if (has_super) {
  90                 super_blk = group_block;
  91                 numblocks++;
  92         }
  93         meta_bg_size = EXT2_DESC_PER_BLOCK(fs->super);
  94         meta_bg = group / meta_bg_size;
  95
  96         if (!(fs->super->s_feature_incompat & EXT2_FEATURE_INCOMPAT_META_BG) ||
  97             (meta_bg < fs->super->s_first_meta_bg)) {
  98                 if (has_super) {
  99                         old_desc_blk = group_block + 1;
 100                         numblocks += old_desc_blocks;
 101                 }
 102         } else {
 103                 if (((group % meta_bg_size) == 0) ||
 104                     ((group % meta_bg_size) == 1) ||
 105                     ((group % meta_bg_size) == (meta_bg_size-1))) {
 106                         if (has_super)
 107                                 has_super = 1;
 108                         new_desc_blk = group_block + has_super;
 109                         numblocks++;
 110                 }
 111         }
 112
 113         if (ret_super_blk)
 114                 *ret_super_blk = super_blk;
 115         if (ret_old_desc_blk)
 116                 *ret_old_desc_blk = old_desc_blk;
 117         if (ret_new_desc_blk)
 118                 *ret_new_desc_blk = new_desc_blk;
 119         if (ret_used_blks)
 120                 *ret_used_blks = numblocks;
 121
 122         return 0;
 123 }
 124
 125 /*
 126  * This function returns the location of the superblock, block group
 127  * descriptors for a given block group.  It currently returns the
 128  * number of free blocks assuming that inode table and allocation
 129  * bitmaps will be in the group.  This is not necessarily the case
 130  * when the flex_bg feature is enabled, so callers should take care!
 131  * It was only really intended for use by mke2fs, and even there it's
 132  * not that useful.
 133  *
 134  * The ext2fs_super_and_bgd_loc2() function is 64-bit block number
 135  * capable and returns the number of blocks used by super block and
 136  * group descriptors.
 137  */
 138 int ext2fs_super_and_bgd_loc(ext2_filsys fs,
 139                              dgrp_t group,
 140                              blk_t *ret_super_blk,
 141                              blk_t *ret_old_desc_blk,
 142                              blk_t *ret_new_desc_blk,
 143                              int *ret_meta_bg)
 144 {
 145         blk64_t ret_super_blk2;
 146         blk64_t ret_old_desc_blk2;
 147         blk64_t ret_new_desc_blk2;
 148         blk_t ret_used_blks;
 149         blk_t numblocks;
 150         unsigned int meta_bg_size;
 151
 152         ext2fs_super_and_bgd_loc2(fs, group, &ret_super_blk2,
 153                                         &ret_old_desc_blk2,
 154                                         &ret_new_desc_blk2,
 155                                         &ret_used_blks);
 156
 157         numblocks = ext2fs_group_blocks_count(fs, group);
 158
 159         if (ret_super_blk)
 160                 *ret_super_blk = (blk_t)ret_super_blk2;
 161         if (ret_old_desc_blk)
 162                 *ret_old_desc_blk = (blk_t)ret_old_desc_blk2;
 163         if (ret_new_desc_blk)
 164                 *ret_new_desc_blk = (blk_t)ret_new_desc_blk2;
 165         if (ret_meta_bg) {
 166                 meta_bg_size = EXT2_DESC_PER_BLOCK(fs->super);
 167                 *ret_meta_bg = group / meta_bg_size;
 168         }
 169
 170         numblocks -= 2 + fs->inode_blocks_per_group + ret_used_blks;
 171
 172         return numblocks;
 173 }
 174
 175 /*
 176  * This function forces out the primary superblock.  We need to only
 177  * write out those fields which we have changed, since if the
 178  * filesystem is mounted, it may have changed some of the other
 179  * fields.
 180  *
 181  * It takes as input a superblock which has already been byte swapped
 182  * (if necessary).
 183  *
 184  */
 185 static errcode_t write_primary_superblock(ext2_filsys fs,
 186                                           struct ext2_super_block *super)
 187 {
 188         __u16           *old_super, *new_super;
 189         int             check_idx, write_idx, size;
 190         errcode_t       retval;
 191
 192         if (!fs->io->manager->write_byte || !fs->orig_super) {
 193         fallback:
 194                 io_channel_set_blksize(fs->io, SUPERBLOCK_OFFSET);
 195                 retval = io_channel_write_blk64(fs->io, 1, -SUPERBLOCK_SIZE,
 196                                               super);
 197                 io_channel_set_blksize(fs->io, fs->blocksize);
 198                 return retval;
 199         }
 200
 201         old_super = (__u16 *) fs->orig_super;
 202         new_super = (__u16 *) super;
 203
 204         for (check_idx = 0; check_idx < SUPERBLOCK_SIZE/2; check_idx++) {
 205                 if (old_super[check_idx] == new_super[check_idx])
 206                         continue;
 207                 write_idx = check_idx;
 208                 for (check_idx++; check_idx < SUPERBLOCK_SIZE/2; check_idx++)
 209                         if (old_super[check_idx] == new_super[check_idx])
 210                                 break;
 211                 size = 2 * (check_idx - write_idx);
 212 #if 0
 213                 printf("Writing %d bytes starting at %d\n",
 214                        size, write_idx*2);
 215 #endif
 216                 retval = io_channel_write_byte(fs->io,
 217                                SUPERBLOCK_OFFSET + (2 * write_idx), size,
 218                                                new_super + write_idx);
 219                 if (retval == EXT2_ET_UNIMPLEMENTED)
 220                         goto fallback;
 221                 if (retval)
 222                         return retval;
 223         }
 224         memcpy(fs->orig_super, super, SUPERBLOCK_SIZE);
 225         return 0;
 226 }
 227
 228
 229 /*
 230  * Updates the revision to EXT2_DYNAMIC_REV
 231  */
 232 void ext2fs_update_dynamic_rev(ext2_filsys fs)
 233 {
 234         struct ext2_super_block *sb = fs->super;
 235
 236         if (sb->s_rev_level > EXT2_GOOD_OLD_REV)
 237                 return;
 238
 239         sb->s_rev_level = EXT2_DYNAMIC_REV;
 240         sb->s_first_ino = EXT2_GOOD_OLD_FIRST_INO;
 241         sb->s_inode_size = EXT2_GOOD_OLD_INODE_SIZE;
 242         /* s_uuid is handled by e2fsck already */
 243         /* other fields should be left alone */
 244 }
 245
 246 static errcode_t write_backup_super(ext2_filsys fs, dgrp_t group,
 247                                     blk64_t group_block,
 248                                     struct ext2_super_block *super_shadow)
 249 {
 250         dgrp_t  sgrp = group;
 251
 252         if (sgrp > ((1 << 16) - 1))
 253                 sgrp = (1 << 16) - 1;
 254 #ifdef WORDS_BIGENDIAN
 255         super_shadow->s_block_group_nr = ext2fs_swab16(sgrp);
 256 #else
 257         fs->super->s_block_group_nr = sgrp;
 258 #endif
 259
 260         return io_channel_write_blk64(fs->io, group_block, -SUPERBLOCK_SIZE,
 261                                     super_shadow);
 262 }
 263
 264 errcode_t ext2fs_flush(ext2_filsys fs)
 265 {
 266         return ext2fs_flush2(fs, 0);
 267 }
 268
 269 errcode_t ext2fs_flush2(ext2_filsys fs, int flags)
 270 {
 271         dgrp_t          i;
 272         errcode_t       retval;
 273         unsigned long   fs_state;
 274         __u32           feature_incompat;
 275         struct ext2_super_block *super_shadow = 0;
 276         struct ext2_group_desc *group_shadow = 0;
 277 #ifdef WORDS_BIGENDIAN
 278         struct ext2_group_desc *gdp;
 279         dgrp_t          j;
 280 #endif
 281         char    *group_ptr;
 282         int     old_desc_blocks;
 283         struct ext2fs_numeric_progress_struct progress;
 284
 285         EXT2_CHECK_MAGIC(fs, EXT2_ET_MAGIC_EXT2FS_FILSYS);
 286
 287         fs_state = fs->super->s_state;
 288         feature_incompat = fs->super->s_feature_incompat;
 289
 290         fs->super->s_wtime = fs->now ? fs->now : time(NULL);
 291         fs->super->s_block_group_nr = 0;
 292 #ifdef WORDS_BIGENDIAN
 293         retval = EXT2_ET_NO_MEMORY;
 294         retval = ext2fs_get_mem(SUPERBLOCK_SIZE, &super_shadow);
 295         if (retval)
 296                 goto errout;
 297         retval = ext2fs_get_array(fs->desc_blocks, fs->blocksize,
 298                                   &group_shadow);
 299         if (retval)
 300                 goto errout;
 301         memcpy(group_shadow, fs->group_desc, (size_t) fs->blocksize *
 302                fs->desc_blocks);
 303
 304         /* swap the group descriptors */
 305         for (j=0; j < fs->group_desc_count; j++) {
 306                 gdp = ext2fs_group_desc(fs, group_shadow, j);
 307                 ext2fs_swap_group_desc2(fs, gdp);
 308         }
 309 #else
 310         super_shadow = fs->super;
 311         group_shadow = ext2fs_group_desc(fs, fs->group_desc, 0);
 312 #endif
 313
 314         /*
 315          * Set the state of the FS to be non-valid.  (The state has
 316          * already been backed up earlier, and will be restored after
 317          * we write out the backup superblocks.)
 318          */
 319         fs->super->s_state &= ~EXT2_VALID_FS;
 320         fs->super->s_feature_incompat &= ~EXT3_FEATURE_INCOMPAT_RECOVER;
 321 #ifdef WORDS_BIGENDIAN
 322         *super_shadow = *fs->super;
 323         ext2fs_swap_super(super_shadow);
 324 #endif
 325
 326         /*
 327          * If this is an external journal device, don't write out the
 328          * block group descriptors or any of the backup superblocks
 329          */
 330         if (fs->super->s_feature_incompat &
 331             EXT3_FEATURE_INCOMPAT_JOURNAL_DEV)
 332                 goto write_primary_superblock_only;
 333
 334         /*
 335          * Write out the master group descriptors, and the backup
 336          * superblocks and group descriptors.
 337          */
 338         group_ptr = (char *) group_shadow;
 339         if (fs->super->s_feature_incompat & EXT2_FEATURE_INCOMPAT_META_BG)
 340                 old_desc_blocks = fs->super->s_first_meta_bg;
 341         else
 342                 old_desc_blocks = fs->desc_blocks;
 343
 344         ext2fs_numeric_progress_init(fs, &progress, NULL,
 345                                      fs->group_desc_count);
 346
 347
 348         for (i = 0; i < fs->group_desc_count; i++) {
 349                 blk64_t super_blk, old_desc_blk, new_desc_blk;
 350
 351                 ext2fs_numeric_progress_update(fs, &progress, i);
 352                 ext2fs_super_and_bgd_loc2(fs, i, &super_blk, &old_desc_blk,
 353                                          &new_desc_blk, 0);
 354
 355                 if (!(fs->flags & EXT2_FLAG_MASTER_SB_ONLY) &&i && super_blk) {
 356                         retval = write_backup_super(fs, i, super_blk,
 357                                                     super_shadow);
 358                         if (retval)
 359                                 goto errout;
 360                 }
 361                 if (fs->flags & EXT2_FLAG_SUPER_ONLY)
 362                         continue;
 363                 if ((old_desc_blk) &&
 364                     (!(fs->flags & EXT2_FLAG_MASTER_SB_ONLY) || (i == 0))) {
 365                         retval = io_channel_write_blk64(fs->io,
 366                               old_desc_blk, old_desc_blocks, group_ptr);
 367                         if (retval)
 368                                 goto errout;
 369                 }
 370                 if (new_desc_blk) {
 371                         int meta_bg = i / EXT2_DESC_PER_BLOCK(fs->super);
 372
 373                         retval = io_channel_write_blk64(fs->io, new_desc_blk,
 374                                 1, group_ptr + (meta_bg*fs->blocksize));
 375                         if (retval)
 376                                 goto errout;
 377                 }
 378         }
 379
 380         ext2fs_numeric_progress_close(fs, &progress, NULL);
 381
 382         /*
 383          * If the write_bitmaps() function is present, call it to
 384          * flush the bitmaps.  This is done this way so that a simple
 385          * program that doesn't mess with the bitmaps doesn't need to
 386          * drag in the bitmaps.c code.
 387          */
 388         if (fs->write_bitmaps) {
 389                 retval = fs->write_bitmaps(fs);
 390                 if (retval)
 391                         goto errout;
 392         }
 393
 394 write_primary_superblock_only:
 395         /*
 396          * Write out master superblock.  This has to be done
 397          * separately, since it is located at a fixed location
 398          * (SUPERBLOCK_OFFSET).  We flush all other pending changes
 399          * out to disk first, just to avoid a race condition with an
 400          * insy-tinsy window....
 401          */
 402
 403         fs->super->s_block_group_nr = 0;
 404         fs->super->s_state = fs_state;
 405         fs->super->s_feature_incompat = feature_incompat;
 406 #ifdef WORDS_BIGENDIAN
 407         *super_shadow = *fs->super;
 408         ext2fs_swap_super(super_shadow);
 409 #endif
 410
 411         if (!(flags & EXT2_FLAG_FLUSH_NO_SYNC))
 412                 retval = io_channel_flush(fs->io);
 413         retval = write_primary_superblock(fs, super_shadow);
 414         if (retval)
 415                 goto errout;
 416
 417         fs->flags &= ~EXT2_FLAG_DIRTY;
 418
 419         if (!(flags & EXT2_FLAG_FLUSH_NO_SYNC))
 420                 retval = io_channel_flush(fs->io);
 421 errout:
 422         fs->super->s_state = fs_state;
 423 #ifdef WORDS_BIGENDIAN
 424         if (super_shadow)
 425                 ext2fs_free_mem(&super_shadow);
 426         if (group_shadow)
 427                 ext2fs_free_mem(&group_shadow);
 428 #endif
 429         return retval;
 430 }
 431
 432 errcode_t ext2fs_close(ext2_filsys fs)
 433 {
 434         return ext2fs_close2(fs, 0);
 435 }
 436
 437 errcode_t ext2fs_close2(ext2_filsys fs, int flags)
 438 {
 439         errcode_t       retval;
 440         int             meta_blks;
 441         io_stats stats = 0;
 442
 443         EXT2_CHECK_MAGIC(fs, EXT2_ET_MAGIC_EXT2FS_FILSYS);
 444
 445         if (fs->write_bitmaps) {
 446                 retval = fs->write_bitmaps(fs);
 447                 if (retval)
 448                         return retval;
 449         }
 450         if (fs->super->s_kbytes_written &&
 451             fs->io->manager->get_stats)
 452                 fs->io->manager->get_stats(fs->io, &stats);
 453         if (stats && stats->bytes_written && (fs->flags & EXT2_FLAG_RW)) {
 454                 fs->super->s_kbytes_written += stats->bytes_written >> 10;
 455                 meta_blks = fs->desc_blocks + 1;
 456                 if (!(fs->flags & EXT2_FLAG_SUPER_ONLY))
 457                         fs->super->s_kbytes_written += meta_blks /
 458                                 (fs->blocksize / 1024);
 459                 if ((fs->flags & EXT2_FLAG_DIRTY) == 0)
 460                         fs->flags |= EXT2_FLAG_SUPER_ONLY | EXT2_FLAG_DIRTY;
 461         }
 462         if (fs->flags & EXT2_FLAG_DIRTY) {
 463                 retval = ext2fs_flush2(fs, flags);
 464                 if (retval)
 465                         return retval;
 466         }
 467
 468         retval = ext2fs_mmp_stop(fs);
 469         if (retval)
 470                 return retval;
 471
 472         ext2fs_free(fs);
 473         return 0;
 474 }
 475