1 files changed, 22 insertions, 0 deletions
diff --git a/fs/xfs/scrub/bitmap.c b/fs/xfs/scrub/bitmap.c
index dc139f0031dc..85e5beda186f 100644
--- a/fs/xfs/scrub/bitmap.c
+++ b/fs/xfs/scrub/bitmap.c
@@ -396,3 +396,25 @@ xbitmap_empty(
 {
 	return bitmap->xb_root.rb_root.rb_node == NULL;
 }
+
+/* Is the start of the range set or clear?  And for how long? */
+bool
+xbitmap_test(
+	struct xbitmap		*bitmap,
+	uint64_t		start,
+	uint64_t		*len)
+{
+	struct xbitmap_node	*bn;
+	uint64_t		last = start + *len - 1;
+
+	bn = xbitmap_tree_iter_first(&bitmap->xb_root, start, last);
+	if (!bn)
+		return false;
+	if (bn->bn_start <= start) {
+		if (bn->bn_last < last)
+			*len = bn->bn_last - start + 1;
+		return true;
+	}
+	*len = bn->bn_start - start;
+	return false;
+}