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ext4: check for out-of-order index extents in ext4_valid_extent_entries()

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After commit 5946d089379a ("ext4: check for overlapping extents in
ext4_valid_extent_entries()"), we can check out the overlapping extent
entry in leaf extent blocks. But the out-of-order extent entry in index
extent blocks could also trigger bad things if the filesystem is
inconsistent. So this patch add a check to figure out the out-of-order
index extents and return error.

Signed-off-by: Zhang Yi <yi.zhang@huawei.com>
Reviewed-by: Theodore Ts'o <tytso@mit.edu>
Link: https://lore.kernel.org/r/20210908120850.4012324-2-yi.zhang@huawei.com
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
This commit is contained in:
Zhang Yi 2021-09-08 20:08:48 +08:00 committed by Theodore Ts'o
parent 31d21d219b
commit 8dd27feced
1 changed files with 12 additions and 5 deletions
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17
fs/ext4/extents.c
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@ -357,6 +357,9 @@ static int ext4_valid_extent_entries(struct inode *inode,
ext4_fsblk_t *pblk, int depth)
{
unsigned short entries;
ext4_lblk_t lblock = 0;
ext4_lblk_t prev = 0;
if (eh->eh_entries == 0)
return 1;
@ -365,31 +368,35 @@ static int ext4_valid_extent_entries(struct inode *inode,
if (depth == 0) {
/* leaf entries */
struct ext4_extent *ext = EXT_FIRST_EXTENT(eh);
ext4_lblk_t lblock = 0;
ext4_lblk_t prev = 0;
int len = 0;
while (entries) {
if (!ext4_valid_extent(inode, ext))
return 0;
/* Check for overlapping extents */
lblock = le32_to_cpu(ext->ee_block);
len = ext4_ext_get_actual_len(ext);
if ((lblock <= prev) && prev) {
*pblk = ext4_ext_pblock(ext);
return 0;
}
prev = lblock + ext4_ext_get_actual_len(ext) - 1;
ext++;
entries--;
prev = lblock + len - 1;
}
} else {
struct ext4_extent_idx *ext_idx = EXT_FIRST_INDEX(eh);
while (entries) {
if (!ext4_valid_extent_idx(inode, ext_idx))
return 0;
/* Check for overlapping index extents */
lblock = le32_to_cpu(ext_idx->ei_block);
if ((lblock <= prev) && prev) {
*pblk = ext4_idx_pblock(ext_idx);
return 0;
}
ext_idx++;
entries--;
prev = lblock;
}
}
return 1;