From d7eb6fa8f448fc57d4d6935435ba6ffe29a9af37 Mon Sep 17 00:00:00 2001
From: Josef Bacik <josef@redhat.com>
Date: Tue, 14 Jun 2011 16:22:15 -0400
Subject: [PATCH] --- yaml --- r: 253813 b: refs/heads/master c:
 ed0ca14021e5ae3147602128641aa7f742ab227c h: refs/heads/master i:   253811:
 a681b40ca290eb4c870bb0421141e2e5e1edb970 v: v3

---
 [refs]                       |  2 +-
 trunk/fs/btrfs/transaction.c | 14 +++++++++++---
 2 files changed, 12 insertions(+), 4 deletions(-)

diff --git a/[refs] b/[refs]
index b5880ddffd9a..2aaf5ba4900d 100644
--- a/[refs]
+++ b/[refs]
@@ -1,2 +1,2 @@
 ---
-refs/heads/master: 8351583e3f6e430ce8f71913909a96ad5cc6a2f6
+refs/heads/master: ed0ca14021e5ae3147602128641aa7f742ab227c
diff --git a/trunk/fs/btrfs/transaction.c b/trunk/fs/btrfs/transaction.c
index 2b3590b9fe98..56695595e036 100644
--- a/trunk/fs/btrfs/transaction.c
+++ b/trunk/fs/btrfs/transaction.c
@@ -1241,12 +1241,20 @@ int btrfs_commit_transaction(struct btrfs_trans_handle *trans,
 			schedule_timeout(1);
 
 		finish_wait(&cur_trans->writer_wait, &wait);
-		spin_lock(&root->fs_info->trans_lock);
-		root->fs_info->trans_no_join = 1;
-		spin_unlock(&root->fs_info->trans_lock);
 	} while (atomic_read(&cur_trans->num_writers) > 1 ||
 		 (should_grow && cur_trans->num_joined != joined));
 
+	/*
+	 * Ok now we need to make sure to block out any other joins while we
+	 * commit the transaction.  We could have started a join before setting
+	 * no_join so make sure to wait for num_writers to == 1 again.
+	 */
+	spin_lock(&root->fs_info->trans_lock);
+	root->fs_info->trans_no_join = 1;
+	spin_unlock(&root->fs_info->trans_lock);
+	wait_event(cur_trans->writer_wait,
+		   atomic_read(&cur_trans->num_writers) == 1);
+
 	ret = create_pending_snapshots(trans, root->fs_info);
 	BUG_ON(ret);