On May 24, 2018, at 5:36 AM, Jan Kara jack@suse.cz wrote:
ext4_resize_fs() has an off-by-one bug when checking whether growing of a filesystem will not overflow inode count. As a result it allows a filesystem with 8192 inodes per group to grow to 64TB which overflows inode count to 0 and makes filesystem unusable. Fix it.
CC: stable@vger.kernel.org Fixes: 3f8a6411fbada1fa482276591e037f3b1adcf55b Reported-by: Jaco Kroon jaco@uls.co.za Signed-off-by: Jan Kara jack@suse.cz
This should be enough to stop the filesystem from exploding. We can look at more complex solutions in a separate patch.
Reviewed-by: Andreas Dilger adilger@dilger.ca
fs/ext4/resize.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/fs/ext4/resize.c b/fs/ext4/resize.c index b6bec270a8e4..d792b7689d92 100644 --- a/fs/ext4/resize.c +++ b/fs/ext4/resize.c @@ -1933,7 +1933,7 @@ int ext4_resize_fs(struct super_block *sb, ext4_fsblk_t n_blocks_count) return 0;
n_group = ext4_get_group_number(sb, n_blocks_count - 1);
- if (n_group > (0xFFFFFFFFUL / EXT4_INODES_PER_GROUP(sb))) {
- if (n_group >= (0xFFFFFFFFUL / EXT4_INODES_PER_GROUP(sb))) { ext4_warning(sb, "resize would cause inodes_count overflow"); return -EINVAL; }
-- 2.13.6
Cheers, Andreas