Btrfs: handle quota reserve failure properly

btrfs/022 was spitting a warning for the case that we exceed the quota.  If we
fail to make our quota reservation we need to clean up our data space
reservation.  Thanks,
Signed-off-by: NJosef Bacik <jbacik@fb.com>
Tested-by: NJeff Mahoney <jeffm@suse.com>
Signed-off-by: NChris Mason <clm@fb.com>

fs/btrfs/extent-tree.c

@@ -4271,13 +4271,10 @@ int btrfs_check_data_free_space(struct inode *inode, u64 start, u64 len)
 	if (ret < 0)
 		return ret;
 
-	/*
-	 * Use new btrfs_qgroup_reserve_data to reserve precious data space
-	 *
-	 * TODO: Find a good method to avoid reserve data space for NOCOW
-	 * range, but don't impact performance on quota disable case.
-	 */
+	/* Use new btrfs_qgroup_reserve_data to reserve precious data space. */
 	ret = btrfs_qgroup_reserve_data(inode, start, len);
+	if (ret)
+		btrfs_free_reserved_data_space_noquota(inode, start, len);
 	return ret;
 }