From: Josef Bacik josef@toxicpanda.com
commit 867ed321f90d06aaba84e2c91de51cd3038825ef upstream.
While testing my error handling patches, I added a error injection site at btrfs_inc_extent_ref, to validate the error handling I added was doing the correct thing. However I hit a pretty ugly corruption while doing this check, with the following error injection stack trace:
btrfs_inc_extent_ref btrfs_copy_root create_reloc_root btrfs_init_reloc_root btrfs_record_root_in_trans btrfs_start_transaction btrfs_update_inode btrfs_update_time touch_atime file_accessed btrfs_file_mmap
This is because we do not catch the error from btrfs_inc_extent_ref, which in practice would be ENOMEM, which means we lose the extent references for a root that has already been allocated and inserted, which is the problem. Fix this by aborting the transaction if we fail to do the reference modification.
CC: stable@vger.kernel.org # 4.4+ Signed-off-by: Josef Bacik josef@toxicpanda.com Reviewed-by: David Sterba dsterba@suse.com Signed-off-by: David Sterba dsterba@suse.com Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- fs/btrfs/ctree.c | 5 +++-- 1 file changed, 3 insertions(+), 2 deletions(-)
--- a/fs/btrfs/ctree.c +++ b/fs/btrfs/ctree.c @@ -279,9 +279,10 @@ int btrfs_copy_root(struct btrfs_trans_h ret = btrfs_inc_ref(trans, root, cow, 1); else ret = btrfs_inc_ref(trans, root, cow, 0); - - if (ret) + if (ret) { + btrfs_abort_transaction(trans, ret); return ret; + }
btrfs_mark_buffer_dirty(cow); *cow_ret = cow;