From 4f9474a25905de165449c899f20f2db0fc39eae0 Mon Sep 17 00:00:00 2001
From: Josef Bacik <jbacik@fusionio.com>
Date: Fri, 14 Sep 2012 11:22:38 -0400
Subject: [PATCH] --- yaml --- r: 332575 b: refs/heads/master c:
 98114659e0d467e2c0ee6f24f2429329328fc312 h: refs/heads/master i:   332573:
 92398b424300456652235387591eab66f4decbff   332571:
 9c61d8b92afb682092dc03ce6ad6e0cfe9943479   332567:
 b7bb3e161b853b43b0bdf4453e66888eb9446bd8   332559:
 cd630e9a8c55423f911bab62954d49f84e0f9b19   332543:
 b713f647912c12be11d881f46b2ea47b149cd17a v: v3

---
 [refs]                       |  2 +-
 trunk/fs/btrfs/transaction.c | 13 +++++++++++--
 2 files changed, 12 insertions(+), 3 deletions(-)

diff --git a/[refs] b/[refs]
index 5908529d3d41..1175ea60ca2d 100644
--- a/[refs]
+++ b/[refs]
@@ -1,2 +1,2 @@
 ---
-refs/heads/master: 6bbe3a9c805fcb8cd8d396dafd32078181a7cdd5
+refs/heads/master: 98114659e0d467e2c0ee6f24f2429329328fc312
diff --git a/trunk/fs/btrfs/transaction.c b/trunk/fs/btrfs/transaction.c
index c9265a603488..a4fe5494d01b 100644
--- a/trunk/fs/btrfs/transaction.c
+++ b/trunk/fs/btrfs/transaction.c
@@ -342,7 +342,15 @@ static struct btrfs_trans_handle *start_transaction(struct btrfs_root *root,
 	if (!h)
 		return ERR_PTR(-ENOMEM);
 
-	if (!__sb_start_write(root->fs_info->sb, SB_FREEZE_FS, false)) {
+	/*
+	 * If we are JOIN_NOLOCK we're already committing a transaction and
+	 * waiting on this guy, so we don't need to do the sb_start_intwrite
+	 * because we're already holding a ref.  We need this because we could
+	 * have raced in and did an fsync() on a file which can kick a commit
+	 * and then we deadlock with somebody doing a freeze.
+	 */
+	if (type != TRANS_JOIN_NOLOCK &&
+	    !__sb_start_write(root->fs_info->sb, SB_FREEZE_FS, false)) {
 		if (type == TRANS_JOIN_FREEZE)
 			return ERR_PTR(-EPERM);
 		sb_start_intwrite(root->fs_info->sb);
@@ -601,7 +609,8 @@ static int __btrfs_end_transaction(struct btrfs_trans_handle *trans,
 		}
 	}
 
-	sb_end_intwrite(root->fs_info->sb);
+	if (lock)
+		sb_end_intwrite(root->fs_info->sb);
 
 	WARN_ON(cur_trans != info->running_transaction);
 	WARN_ON(atomic_read(&cur_trans->num_writers) < 1);