From a68370515356a3eddbfaf7f56418b3cf85d76c2c Mon Sep 17 00:00:00 2001
From: Chris Mason <chris.mason@oracle.com>
Date: Wed, 4 Feb 2009 09:19:41 -0500
Subject: Btrfs: Catch missed bios in the async bio submission thread

The async bio submission thread was missing some bios that were
added after it had decided there was no work left to do.

Signed-off-by: Chris Mason <chris.mason@oracle.com>

diff --git a/fs/btrfs/async-thread.c b/fs/btrfs/async-thread.c
index d5f4e94..f2e80f3 100644
--- a/fs/btrfs/async-thread.c
+++ b/fs/btrfs/async-thread.c
@@ -349,6 +349,7 @@ int btrfs_requeue_work(struct btrfs_work *work)
 {
 	struct btrfs_worker_thread *worker = work->worker;
 	unsigned long flags;
+	int wake = 0;
 
 	if (test_and_set_bit(WORK_QUEUED_BIT, &work->flags))
 		goto out;
@@ -367,10 +368,16 @@ int btrfs_requeue_work(struct btrfs_work *work)
 			       &worker->workers->worker_list);
 		spin_unlock_irqrestore(&worker->workers->lock, flags);
 	}
+	if (!worker->working) {
+		wake = 1;
+		worker->working = 1;
+	}
 
 	spin_unlock_irqrestore(&worker->lock, flags);
-
+	if (wake)
+		wake_up_process(worker->task);
 out:
+
 	return 0;
 }
 
@@ -397,6 +404,7 @@ int btrfs_queue_worker(struct btrfs_workers *workers, struct btrfs_work *work)
 	}
 
 	spin_lock_irqsave(&worker->lock, flags);
+
 	atomic_inc(&worker->num_pending);
 	check_busy_worker(worker);
 	list_add_tail(&work->list, &worker->pending);
diff --git a/fs/btrfs/volumes.c b/fs/btrfs/volumes.c
index fd0bedb..bcd14eb 100644
--- a/fs/btrfs/volumes.c
+++ b/fs/btrfs/volumes.c
@@ -154,6 +154,7 @@ static noinline int run_scheduled_bios(struct btrfs_device *device)
 loop:
 	spin_lock(&device->io_lock);
 
+loop_lock:
 	/* take all the bios off the list at once and process them
 	 * later on (without the lock held).  But, remember the
 	 * tail and other pointers so the bios can be properly reinserted
@@ -203,7 +204,7 @@ loop:
 		 * is now congested.  Back off and let other work structs
 		 * run instead
 		 */
-		if (pending && bdi_write_congested(bdi) &&
+		if (pending && bdi_write_congested(bdi) && num_run > 16 &&
 		    fs_info->fs_devices->open_devices > 1) {
 			struct bio *old_head;
 
@@ -215,7 +216,8 @@ loop:
 				tail->bi_next = old_head;
 			else
 				device->pending_bio_tail = tail;
-			device->running_pending = 0;
+
+			device->running_pending = 1;
 
 			spin_unlock(&device->io_lock);
 			btrfs_requeue_work(&device->work);
@@ -224,6 +226,11 @@ loop:
 	}
 	if (again)
 		goto loop;
+
+	spin_lock(&device->io_lock);
+	if (device->pending_bios)
+		goto loop_lock;
+	spin_unlock(&device->io_lock);
 done:
 	return 0;
 }
-- 
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