---

yaml
---
r: 140324
b: refs/heads/master
c: bedf762
h: refs/heads/master
v: v3

[refs]

@@ -1,2 +1,2 @@
 ---
-refs/heads/master: b765ead57da62cccf7fa21e00e6eed65e9df62b0
+refs/heads/master: bedf762ba3a4b70295661fa70c29c1f18fe0f351

trunk/fs/btrfs/volumes.c

@@ -148,7 +148,7 @@ static noinline int run_scheduled_bios(struct btrfs_device *device)
 	unsigned long limit;
 	unsigned long last_waited = 0;
 
-	bdi = device->bdev->bd_inode->i_mapping->backing_dev_info;
+	bdi = blk_get_backing_dev_info(device->bdev);
 	fs_info = device->dev_root->fs_info;
 	limit = btrfs_async_submit_limit(fs_info);
 	limit = limit * 2 / 3;
@@ -258,6 +258,18 @@ static noinline int run_scheduled_bios(struct btrfs_device *device)
 	if (device->pending_bios)
 		goto loop_lock;
 	spin_unlock(&device->io_lock);
+
+	/*
+	 * IO has already been through a long path to get here.  Checksumming,
+	 * async helper threads, perhaps compression.  We've done a pretty
+	 * good job of collecting a batch of IO and should just unplug
+	 * the device right away.
+	 *
+	 * This will help anyone who is waiting on the IO, they might have
+	 * already unplugged, but managed to do so before the bio they
+	 * cared about found its way down here.
+	 */
+	blk_run_backing_dev(bdi, NULL);
 done:
 	return 0;
 }