4.14-stable review patch. If anyone has any objections, please let me know. ------------------ From: Filipe Manana <fdmanana@xxxxxxxx> commit c5b4a50b74018b3677098151ec5f4fce07d5e6a0 upstream. If we failed during a rename exchange operation after starting/joining a transaction, we would end up replacing the return value, stored in the local 'ret' variable, with the return value from btrfs_end_transaction(). So this could end up returning 0 (success) to user space despite the operation having failed and aborted the transaction, because if there are multiple tasks having a reference on the transaction at the time btrfs_end_transaction() is called by the rename exchange, that function returns 0 (otherwise it returns -EIO and not the original error value). So fix this by not overwriting the return value on error after getting a transaction handle. Fixes: cdd1fedf8261 ("btrfs: add support for RENAME_EXCHANGE and RENAME_WHITEOUT") CC: stable@xxxxxxxxxxxxxxx # 4.9+ Signed-off-by: Filipe Manana <fdmanana@xxxxxxxx> Reviewed-by: David Sterba <dsterba@xxxxxxxx> Signed-off-by: David Sterba <dsterba@xxxxxxxx> Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx> --- fs/btrfs/inode.c | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-) --- a/fs/btrfs/inode.c +++ b/fs/btrfs/inode.c @@ -9769,6 +9769,7 @@ static int btrfs_rename_exchange(struct u64 new_idx = 0; u64 root_objectid; int ret; + int ret2; bool root_log_pinned = false; bool dest_log_pinned = false; @@ -9965,7 +9966,8 @@ out_fail: dest_log_pinned = false; } } - ret = btrfs_end_transaction(trans); + ret2 = btrfs_end_transaction(trans); + ret = ret ? ret : ret2; out_notrans: if (new_ino == BTRFS_FIRST_FREE_OBJECTID) up_read(&fs_info->subvol_sem);