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authorJohannes Thumshirn <jthumshirn@suse.de>2019-02-18 13:28:37 +0300
committerDavid Sterba <dsterba@suse.com>2019-02-25 16:13:41 +0300
commit349ae63f40638a28c6fce52e8447c2d14b84cc0c (patch)
treea5d03c2b46557502b02ce7937be65a61d046005e /fs/btrfs
parente49be14b8d80e23bb7c53d78c21717a474ade76b (diff)
downloadlinux-349ae63f40638a28c6fce52e8447c2d14b84cc0c.tar.xz
btrfs: ensure that a DUP or RAID1 block group has exactly two stripes
We recently had a customer issue with a corrupted filesystem. When trying to mount this image btrfs panicked with a division by zero in calc_stripe_length(). The corrupt chunk had a 'num_stripes' value of 1. calc_stripe_length() takes this value and divides it by the number of copies the RAID profile is expected to have to calculate the amount of data stripes. As a DUP profile is expected to have 2 copies this division resulted in 1/2 = 0. Later then the 'data_stripes' variable is used as a divisor in the stripe length calculation which results in a division by 0 and thus a kernel panic. When encountering a filesystem with a DUP block group and a 'num_stripes' value unequal to 2, refuse mounting as the image is corrupted and will lead to unexpected behaviour. Code inspection showed a RAID1 block group has the same issues. Fixes: e06cd3dd7cea ("Btrfs: add validadtion checks for chunk loading") CC: stable@vger.kernel.org # 4.4+ Reviewed-by: Qu Wenruo <wqu@suse.com> Reviewed-by: Nikolay Borisov <nborisov@suse.com> Signed-off-by: Johannes Thumshirn <jthumshirn@suse.de> Reviewed-by: David Sterba <dsterba@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
Diffstat (limited to 'fs/btrfs')
-rw-r--r--fs/btrfs/volumes.c4
1 files changed, 2 insertions, 2 deletions
diff --git a/fs/btrfs/volumes.c b/fs/btrfs/volumes.c
index 03f223aa7194..9024eee889b9 100644
--- a/fs/btrfs/volumes.c
+++ b/fs/btrfs/volumes.c
@@ -6791,10 +6791,10 @@ static int btrfs_check_chunk_valid(struct btrfs_fs_info *fs_info,
}
if ((type & BTRFS_BLOCK_GROUP_RAID10 && sub_stripes != 2) ||
- (type & BTRFS_BLOCK_GROUP_RAID1 && num_stripes < 1) ||
+ (type & BTRFS_BLOCK_GROUP_RAID1 && num_stripes != 2) ||
(type & BTRFS_BLOCK_GROUP_RAID5 && num_stripes < 2) ||
(type & BTRFS_BLOCK_GROUP_RAID6 && num_stripes < 3) ||
- (type & BTRFS_BLOCK_GROUP_DUP && num_stripes > 2) ||
+ (type & BTRFS_BLOCK_GROUP_DUP && num_stripes != 2) ||
((type & BTRFS_BLOCK_GROUP_PROFILE_MASK) == 0 &&
num_stripes != 1)) {
btrfs_err(fs_info,