btrfs: return ENODATA in case RST lookup fails

In case a lookup in the RAID stripe-tree fails, return ENODATA instead of
ENOENT to better distinguish stripe-tree lookups from other code paths
where we return ENOENT.

Suggested-by: Josef Bacik <josef@toxicpanda.com>
Reviewed-by: Josef Bacik <josef@toxicpanda.com>
Signed-off-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>

fs/btrfs/raid-stripe-tree.c

@@ -234,7 +234,7 @@ int btrfs_get_raid_extent_offset(struct btrfs_fs_info *fs_info,
 		found_end = found_logical + found_length;
 
 		if (found_logical > end) {
-			ret = -ENOENT;
+			ret = -ENODATA;
 			goto out;
 		}
 
@@ -280,10 +280,10 @@ int btrfs_get_raid_extent_offset(struct btrfs_fs_info *fs_info,
 	}
 
 	/* If we're here, we haven't found the requested devid in the stripe. */
-	ret = -ENOENT;
+	ret = -ENODATA;
 out:
 	if (ret > 0)
-		ret = -ENOENT;
+		ret = -ENODATA;
 	if (ret && ret != -EIO && !stripe->rst_search_commit_root) {
 		btrfs_debug(fs_info,
 		"cannot find raid-stripe for logical [%llu, %llu] devid %llu, profile %s",