4.9-stable review patch. If anyone has any objections, please let me know.
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From: Filipe Manana fdmanana@suse.com
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@vger.kernel.org # 4.9+ Signed-off-by: Filipe Manana fdmanana@suse.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/inode.c | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-)
--- a/fs/btrfs/inode.c +++ b/fs/btrfs/inode.c @@ -9561,6 +9561,7 @@ 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;
@@ -9751,7 +9752,8 @@ out_fail: dest_log_pinned = false; } } - ret = btrfs_end_transaction(trans, root); + ret2 = btrfs_end_transaction(trans, root); + ret = ret ? ret : ret2; out_notrans: if (new_ino == BTRFS_FIRST_FREE_OBJECTID) up_read(&dest->fs_info->subvol_sem);