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- #include <stdio.h>
- #if HAVE_UNISTD_H
- #include <unistd.h>
- #endif
- #include <time.h>
- #include <string.h>
- #include "ext2_fs.h"
- #include "ext2fsP.h"
- static int test_root(int a, int b)
- {
- if (a == 0)
- return 1;
- while (1) {
- if (a == 1)
- return 1;
- if (a % b)
- return 0;
- a = a / b;
- }
- }
- int ext2fs_bg_has_super(ext2_filsys fs, int group_block)
- {
- if (!(fs->super->s_feature_ro_compat &
- EXT2_FEATURE_RO_COMPAT_SPARSE_SUPER))
- return 1;
- if (test_root(group_block, 3) || (test_root(group_block, 5)) ||
- test_root(group_block, 7))
- return 1;
- return 0;
- }
- int ext2fs_super_and_bgd_loc(ext2_filsys fs,
- dgrp_t group,
- blk_t *ret_super_blk,
- blk_t *ret_old_desc_blk,
- blk_t *ret_new_desc_blk,
- int *ret_meta_bg)
- {
- blk_t group_block, super_blk = 0, old_desc_blk = 0, new_desc_blk = 0;
- unsigned int meta_bg, meta_bg_size;
- int numblocks, has_super;
- int old_desc_blocks;
- group_block = fs->super->s_first_data_block +
- (group * fs->super->s_blocks_per_group);
- if (fs->super->s_feature_incompat & EXT2_FEATURE_INCOMPAT_META_BG)
- old_desc_blocks = fs->super->s_first_meta_bg;
- else
- old_desc_blocks =
- fs->desc_blocks + fs->super->s_reserved_gdt_blocks;
- if (group == fs->group_desc_count-1) {
- numblocks = (fs->super->s_blocks_count -
- fs->super->s_first_data_block) %
- fs->super->s_blocks_per_group;
- if (!numblocks)
- numblocks = fs->super->s_blocks_per_group;
- } else
- numblocks = fs->super->s_blocks_per_group;
- has_super = ext2fs_bg_has_super(fs, group);
- if (has_super) {
- super_blk = group_block;
- numblocks--;
- }
- meta_bg_size = (fs->blocksize / sizeof (struct ext2_group_desc));
- meta_bg = group / meta_bg_size;
- if (!(fs->super->s_feature_incompat & EXT2_FEATURE_INCOMPAT_META_BG) ||
- (meta_bg < fs->super->s_first_meta_bg)) {
- if (has_super) {
- old_desc_blk = group_block + 1;
- numblocks -= old_desc_blocks;
- }
- } else {
- if (((group % meta_bg_size) == 0) ||
- ((group % meta_bg_size) == 1) ||
- ((group % meta_bg_size) == (meta_bg_size-1))) {
- if (has_super)
- has_super = 1;
- new_desc_blk = group_block + has_super;
- numblocks--;
- }
- }
- numblocks -= 2 + fs->inode_blocks_per_group;
- if (ret_super_blk)
- *ret_super_blk = super_blk;
- if (ret_old_desc_blk)
- *ret_old_desc_blk = old_desc_blk;
- if (ret_new_desc_blk)
- *ret_new_desc_blk = new_desc_blk;
- if (ret_meta_bg)
- *ret_meta_bg = meta_bg;
- return numblocks;
- }
- static errcode_t write_primary_superblock(ext2_filsys fs,
- struct ext2_super_block *super)
- {
- __u16 *old_super, *new_super;
- int check_idx, write_idx, size;
- errcode_t retval;
- if (!fs->io->manager->write_byte || !fs->orig_super) {
- io_channel_set_blksize(fs->io, SUPERBLOCK_OFFSET);
- retval = io_channel_write_blk(fs->io, 1, -SUPERBLOCK_SIZE,
- super);
- io_channel_set_blksize(fs->io, fs->blocksize);
- return retval;
- }
- old_super = (__u16 *) fs->orig_super;
- new_super = (__u16 *) super;
- for (check_idx = 0; check_idx < SUPERBLOCK_SIZE/2; check_idx++) {
- if (old_super[check_idx] == new_super[check_idx])
- continue;
- write_idx = check_idx;
- for (check_idx++; check_idx < SUPERBLOCK_SIZE/2; check_idx++)
- if (old_super[check_idx] == new_super[check_idx])
- break;
- size = 2 * (check_idx - write_idx);
- retval = io_channel_write_byte(fs->io,
- SUPERBLOCK_OFFSET + (2 * write_idx), size,
- new_super + write_idx);
- if (retval)
- return retval;
- }
- memcpy(fs->orig_super, super, SUPERBLOCK_SIZE);
- return 0;
- }
- void ext2fs_update_dynamic_rev(ext2_filsys fs)
- {
- struct ext2_super_block *sb = fs->super;
- if (sb->s_rev_level > EXT2_GOOD_OLD_REV)
- return;
- sb->s_rev_level = EXT2_DYNAMIC_REV;
- sb->s_first_ino = EXT2_GOOD_OLD_FIRST_INO;
- sb->s_inode_size = EXT2_GOOD_OLD_INODE_SIZE;
-
-
- }
- static errcode_t write_backup_super(ext2_filsys fs, dgrp_t group,
- blk_t group_block,
- struct ext2_super_block *super_shadow)
- {
- dgrp_t sgrp = group;
- if (sgrp > ((1 << 16) - 1))
- sgrp = (1 << 16) - 1;
- #if BB_BIG_ENDIAN
- if (fs->flags & EXT2_FLAG_SWAP_BYTES)
- super_shadow->s_block_group_nr = ext2fs_swab16(sgrp);
- else
- #endif
- fs->super->s_block_group_nr = sgrp;
- return io_channel_write_blk(fs->io, group_block, -SUPERBLOCK_SIZE,
- super_shadow);
- }
- errcode_t ext2fs_flush(ext2_filsys fs)
- {
- dgrp_t i;
- blk_t group_block;
- errcode_t retval;
- unsigned long fs_state;
- struct ext2_super_block *super_shadow = 0;
- struct ext2_group_desc *group_shadow = 0;
- char *group_ptr;
- int old_desc_blocks;
- #if BB_BIG_ENDIAN
- dgrp_t j;
- struct ext2_group_desc *s, *t;
- #endif
- EXT2_CHECK_MAGIC(fs, EXT2_ET_MAGIC_EXT2FS_FILSYS);
- fs_state = fs->super->s_state;
- fs->super->s_wtime = time(NULL);
- fs->super->s_block_group_nr = 0;
- #if BB_BIG_ENDIAN
- if (fs->flags & EXT2_FLAG_SWAP_BYTES) {
- retval = EXT2_ET_NO_MEMORY;
- retval = ext2fs_get_mem(SUPERBLOCK_SIZE, &super_shadow);
- if (retval)
- goto errout;
- retval = ext2fs_get_mem((size_t)(fs->blocksize *
- fs->desc_blocks),
- &group_shadow);
- if (retval)
- goto errout;
- memset(group_shadow, 0, (size_t) fs->blocksize *
- fs->desc_blocks);
-
- for (j=0, s=fs->group_desc, t=group_shadow;
- j < fs->group_desc_count; j++, t++, s++) {
- *t = *s;
- ext2fs_swap_group_desc(t);
- }
- } else {
- super_shadow = fs->super;
- group_shadow = fs->group_desc;
- }
- #else
- super_shadow = fs->super;
- group_shadow = fs->group_desc;
- #endif
-
- if (fs->super->s_feature_incompat &
- EXT3_FEATURE_INCOMPAT_JOURNAL_DEV)
- goto write_primary_superblock_only;
-
- fs->super->s_state &= ~EXT2_VALID_FS;
- #if BB_BIG_ENDIAN
- if (fs->flags & EXT2_FLAG_SWAP_BYTES) {
- *super_shadow = *fs->super;
- ext2fs_swap_super(super_shadow);
- }
- #endif
-
- group_block = fs->super->s_first_data_block;
- group_ptr = (char *) group_shadow;
- if (fs->super->s_feature_incompat & EXT2_FEATURE_INCOMPAT_META_BG)
- old_desc_blocks = fs->super->s_first_meta_bg;
- else
- old_desc_blocks = fs->desc_blocks;
- for (i = 0; i < fs->group_desc_count; i++) {
- blk_t super_blk, old_desc_blk, new_desc_blk;
- int meta_bg;
- ext2fs_super_and_bgd_loc(fs, i, &super_blk, &old_desc_blk,
- &new_desc_blk, &meta_bg);
- if (!(fs->flags & EXT2_FLAG_MASTER_SB_ONLY) &&i && super_blk) {
- retval = write_backup_super(fs, i, super_blk,
- super_shadow);
- if (retval)
- goto errout;
- }
- if (fs->flags & EXT2_FLAG_SUPER_ONLY)
- continue;
- if ((old_desc_blk) &&
- (!(fs->flags & EXT2_FLAG_MASTER_SB_ONLY) || (i == 0))) {
- retval = io_channel_write_blk(fs->io,
- old_desc_blk, old_desc_blocks, group_ptr);
- if (retval)
- goto errout;
- }
- if (new_desc_blk) {
- retval = io_channel_write_blk(fs->io, new_desc_blk,
- 1, group_ptr + (meta_bg*fs->blocksize));
- if (retval)
- goto errout;
- }
- }
- fs->super->s_block_group_nr = 0;
- fs->super->s_state = fs_state;
- #if BB_BIG_ENDIAN
- if (fs->flags & EXT2_FLAG_SWAP_BYTES) {
- *super_shadow = *fs->super;
- ext2fs_swap_super(super_shadow);
- }
- #endif
-
- if (fs->write_bitmaps) {
- retval = fs->write_bitmaps(fs);
- if (retval)
- goto errout;
- }
- write_primary_superblock_only:
-
- retval = io_channel_flush(fs->io);
- retval = write_primary_superblock(fs, super_shadow);
- if (retval)
- goto errout;
- fs->flags &= ~EXT2_FLAG_DIRTY;
- retval = io_channel_flush(fs->io);
- errout:
- fs->super->s_state = fs_state;
- if (fs->flags & EXT2_FLAG_SWAP_BYTES) {
- if (super_shadow)
- ext2fs_free_mem(&super_shadow);
- if (group_shadow)
- ext2fs_free_mem(&group_shadow);
- }
- return retval;
- }
- errcode_t ext2fs_close(ext2_filsys fs)
- {
- errcode_t retval;
- EXT2_CHECK_MAGIC(fs, EXT2_ET_MAGIC_EXT2FS_FILSYS);
- if (fs->flags & EXT2_FLAG_DIRTY) {
- retval = ext2fs_flush(fs);
- if (retval)
- return retval;
- }
- if (fs->write_bitmaps) {
- retval = fs->write_bitmaps(fs);
- if (retval)
- return retval;
- }
- ext2fs_free(fs);
- return 0;
- }
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