diff --git a/kmod/src/btree.c b/kmod/src/btree.c
index 069a50bf..23878451 100644
--- a/kmod/src/btree.c
+++ b/kmod/src/btree.c
@@ -953,3 +953,38 @@ void scoutfs_btree_release(struct scoutfs_btree_cursor *curs)
 	}
 	curs->bl = NULL;
 }
+
+/*
+ * Find the first missing key between the caller's keys, inclusive.  Set
+ * the caller's hole key and return 0 if we find a missing key.  Return
+ * -ENOSPC if all the keys in the range were present or -errno on errors.
+ *
+ * The caller ensures that it's safe for us to be walking this region
+ * of the tree.
+ */
+int scoutfs_btree_hole(struct super_block *sb, struct scoutfs_key *first,
+		       struct scoutfs_key *last, struct scoutfs_key *hole)
+{
+	DECLARE_SCOUTFS_BTREE_CURSOR(curs);
+	int ret;
+
+	*hole = *first;
+	while ((ret = scoutfs_btree_next(sb, first, last, &curs)) > 0) {
+		/* return our expected hole if we skipped it */
+		if (scoutfs_key_cmp(hole, curs.key) < 0)
+			break;
+
+		*hole = *curs.key;
+		scoutfs_inc_key(hole);
+	}
+	scoutfs_btree_release(&curs);
+
+	if (ret >= 0) {
+		if (scoutfs_key_cmp(hole, last) <= 0)
+			ret = 0;
+		else
+			ret = -ENOSPC;
+	}
+
+	return ret;
+}
diff --git a/kmod/src/btree.h b/kmod/src/btree.h
index e902a6bd..5804cbc3 100644
--- a/kmod/src/btree.h
+++ b/kmod/src/btree.h
@@ -28,6 +28,8 @@ int scoutfs_btree_next(struct super_block *sb, struct scoutfs_key *first,
 int scoutfs_btree_dirty(struct super_block *sb, struct scoutfs_key *key);
 void scoutfs_btree_update(struct super_block *sb, struct scoutfs_key *key,
                           struct scoutfs_btree_cursor *curs);
+int scoutfs_btree_hole(struct super_block *sb, struct scoutfs_key *first,
+		       struct scoutfs_key *last, struct scoutfs_key *hole);
 
 void scoutfs_btree_release(struct scoutfs_btree_cursor *curs);
 
diff --git a/kmod/src/dir.c b/kmod/src/dir.c
index 730cc7b2..39745fb7 100644
--- a/kmod/src/dir.c
+++ b/kmod/src/dir.c
@@ -341,21 +341,10 @@ static int scoutfs_mknod(struct inode *dir, struct dentry *dentry, umode_t mode,
 	scoutfs_set_key(&last, scoutfs_ino(dir), SCOUTFS_DIRENT_KEY,
 			last_dirent_key_offset(h));
 
-	/* find the first unoccupied key offset after the hashed name */
-	key = first;
-	while ((ret = scoutfs_btree_next(sb, &first, &last, &curs)) > 0) {
-		key = *curs.key;
-		scoutfs_inc_key(&key);
-	}
-	scoutfs_btree_release(&curs);
-	if (ret < 0)
+	ret = scoutfs_btree_hole(sb, &first, &last, &key);
+	if (ret)
 		goto out;
 
-	if (scoutfs_key_cmp(&key, &last) > 0) {
-		ret = -ENOSPC;
-		goto out;
-	}
-
 	ret = scoutfs_btree_insert(sb, &key, bytes, &curs);
 	if (ret)
 		goto out;