--- zzzz-none-000/linux-3.10.107/fs/nilfs2/bmap.c	2017-06-27 09:49:32.000000000 +0000
+++ scorpion-7490-727/linux-3.10.107/fs/nilfs2/bmap.c	2021-02-04 17:41:59.000000000 +0000
@@ -152,9 +152,7 @@
  *
  * %-EEXIST - A record associated with @key already exist.
  */
-int nilfs_bmap_insert(struct nilfs_bmap *bmap,
-		      unsigned long key,
-		      unsigned long rec)
+int nilfs_bmap_insert(struct nilfs_bmap *bmap, __u64 key, unsigned long rec)
 {
 	int ret;
 
@@ -191,19 +189,47 @@
 	return bmap->b_ops->bop_delete(bmap, key);
 }
 
-int nilfs_bmap_last_key(struct nilfs_bmap *bmap, unsigned long *key)
+/**
+ * nilfs_bmap_seek_key - seek a valid entry and return its key
+ * @bmap: bmap struct
+ * @start: start key number
+ * @keyp: place to store valid key
+ *
+ * Description: nilfs_bmap_seek_key() seeks a valid key on @bmap
+ * starting from @start, and stores it to @keyp if found.
+ *
+ * Return Value: On success, 0 is returned. On error, one of the following
+ * negative error codes is returned.
+ *
+ * %-EIO - I/O error.
+ *
+ * %-ENOMEM - Insufficient amount of memory available.
+ *
+ * %-ENOENT - No valid entry was found
+ */
+int nilfs_bmap_seek_key(struct nilfs_bmap *bmap, __u64 start, __u64 *keyp)
 {
-	__u64 lastkey;
 	int ret;
 
 	down_read(&bmap->b_sem);
-	ret = bmap->b_ops->bop_last_key(bmap, &lastkey);
+	ret = bmap->b_ops->bop_seek_key(bmap, start, keyp);
+	up_read(&bmap->b_sem);
+
+	if (ret < 0)
+		ret = nilfs_bmap_convert_error(bmap, __func__, ret);
+	return ret;
+}
+
+int nilfs_bmap_last_key(struct nilfs_bmap *bmap, __u64 *keyp)
+{
+	int ret;
+
+	down_read(&bmap->b_sem);
+	ret = bmap->b_ops->bop_last_key(bmap, keyp);
 	up_read(&bmap->b_sem);
 
 	if (ret < 0)
 		ret = nilfs_bmap_convert_error(bmap, __func__, ret);
-	else
-		*key = lastkey;
 	return ret;
 }
 
@@ -224,7 +250,7 @@
  *
  * %-ENOENT - A record associated with @key does not exist.
  */
-int nilfs_bmap_delete(struct nilfs_bmap *bmap, unsigned long key)
+int nilfs_bmap_delete(struct nilfs_bmap *bmap, __u64 key)
 {
 	int ret;
 
@@ -235,7 +261,7 @@
 	return nilfs_bmap_convert_error(bmap, __func__, ret);
 }
 
-static int nilfs_bmap_do_truncate(struct nilfs_bmap *bmap, unsigned long key)
+static int nilfs_bmap_do_truncate(struct nilfs_bmap *bmap, __u64 key)
 {
 	__u64 lastkey;
 	int ret;
@@ -276,7 +302,7 @@
  *
  * %-ENOMEM - Insufficient amount of memory available.
  */
-int nilfs_bmap_truncate(struct nilfs_bmap *bmap, unsigned long key)
+int nilfs_bmap_truncate(struct nilfs_bmap *bmap, __u64 key)
 {
 	int ret;