On thu, 8 Dec 2011 10:04:34 -0800, Kamal Mostafa wrote:

 /**
- * writeback_inodes_sb_if_idle	-	start writeback if none underway
+ * try_to_writeback_inodes_sb_nr	-	start writeback if none underway
  * @sb: the superblock
  * @nr: the number of pages to write
  *
  * Invoke writeback_inodes_sb if no writeback is currently underway.
  * Returns 1 if writeback was started, 0 if not.
  */
-int writeback_inodes_sb_nr_if_idle(struct super_block *sb,
+int try_to_writeback_inodes_sb_nr(struct super_block *sb,
 				   unsigned long nr,
 				   enum wb_reason reason)
 {
 	if (!writeback_in_progress(sb->s_bdi)) {
 		down_read(&sb->s_umount);
-		writeback_inodes_sb_nr(sb, nr, reason);
+		if (nr == 0)
+			writeback_inodes_sb(sb, reason);
+		else
+			writeback_inodes_sb_nr(sb, nr, reason);
 		up_read(&sb->s_umount);
 		return 1;
 	} else
 		return 0;

The comment said "Returns 1 if writeback was started", so if writeback_in_progress()
return true, I think this function also should return 1.

BTW: Does anyone know when this patchset will be merged into the main tree?

Thanks
Miao