diff --git a/fs/fs-writeback.c b/fs/fs-writeback.c
index 49bc1b8..f6c2155 100644
--- a/fs/fs-writeback.c
+++ b/fs/fs-writeback.c
@@ -1187,6 +1187,23 @@
 EXPORT_SYMBOL(writeback_inodes_sb);
 
 /**
+ * writeback_inodes_sb_if_idle	-	start writeback if none underway
+ * @sb: the superblock
+ *
+ * Invoke writeback_inodes_sb if no writeback is currently underway.
+ * Returns 1 if writeback was started, 0 if not.
+ */
+int writeback_inodes_sb_if_idle(struct super_block *sb)
+{
+	if (!writeback_in_progress(sb->s_bdi)) {
+		writeback_inodes_sb(sb);
+		return 1;
+	} else
+		return 0;
+}
+EXPORT_SYMBOL(writeback_inodes_sb_if_idle);
+
+/**
  * sync_inodes_sb	-	sync sb inode pages
  * @sb: the superblock
  *
diff --git a/include/linux/writeback.h b/include/linux/writeback.h
index c18c008..76e8903 100644
--- a/include/linux/writeback.h
+++ b/include/linux/writeback.h
@@ -70,6 +70,7 @@
 struct bdi_writeback;
 int inode_wait(void *);
 void writeback_inodes_sb(struct super_block *);
+int writeback_inodes_sb_if_idle(struct super_block *);
 void sync_inodes_sb(struct super_block *);
 void writeback_inodes_wbc(struct writeback_control *wbc);
 long wb_do_writeback(struct bdi_writeback *wb, int force_wait);