btrfs: use __u16 for the return value of btrfs_qgroup_level()

The qgroup level is limited to u16, so no need to use u64 for it.
Signed-off-by: Qu Wenruo <wqu@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>

fs/btrfs/qgroup.c

@@ -538,7 +538,7 @@ bool btrfs_check_quota_leak(struct btrfs_fs_info *fs_info)
 			if (qgroup->rsv.values[i]) {
 				ret = true;
 				btrfs_warn(fs_info,
-		"qgroup %llu/%llu has unreleased space, type %d rsv %llu",
+		"qgroup %hu/%llu has unreleased space, type %d rsv %llu",
 				   btrfs_qgroup_level(qgroup->qgroupid),
 				   btrfs_qgroup_subvolid(qgroup->qgroupid),
 				   i, qgroup->rsv.values[i]);

include/uapi/linux/btrfs_tree.h

@@ -913,9 +913,9 @@ struct btrfs_free_space_info {
 #define BTRFS_FREE_SPACE_USING_BITMAPS (1ULL << 0)
 
 #define BTRFS_QGROUP_LEVEL_SHIFT		48
-static inline __u64 btrfs_qgroup_level(__u64 qgroupid)
+static inline __u16 btrfs_qgroup_level(__u64 qgroupid)
 {
-	return qgroupid >> BTRFS_QGROUP_LEVEL_SHIFT;
+	return (__u16)(qgroupid >> BTRFS_QGROUP_LEVEL_SHIFT);
 }
 
 /*