fs-writeback: Add helper function to start writeback if idle

[pandora-kernel.git] / fs / fs-writeback.c

diff --git a/fs/fs-writeback.c b/fs/fs-writeback.c
index 49bc1b8..f6c2155 100644 (file)
--- a/fs/fs-writeback.c
+++ b/fs/fs-writeback.c
@@ -1186,6 +1186,23 @@ void writeback_inodes_sb(struct super_block *sb)
 }
 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