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: Josef Bacik <jbacik@fb.com>
Tested-by: Jeff Mahoney <jeffm@suse.com>
Signed-off-by: Chris Mason <clm@fb.com>
diff --git a/fs/btrfs/extent-tree.c b/fs/btrfs/extent-tree.c
index d09cf7a..db76cc1 100644
--- a/fs/btrfs/extent-tree.c
+++ b/fs/btrfs/extent-tree.c
@@ -4271,13 +4271,10 @@
 	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;
 }