From 9c61d8b92afb682092dc03ce6ad6e0cfe9943479 Mon Sep 17 00:00:00 2001
From: Josef Bacik <jbacik@fusionio.com>
Date: Fri, 14 Sep 2012 10:34:40 -0400
Subject: [PATCH] --- yaml --- r: 332571 b: refs/heads/master c:
 60376ce4a8396bc5cd777be05b6a9bf044520f42 h: refs/heads/master i:   332569:
 14450dc78dcf7af8be86c7f60dbf2aa695806993   332567:
 b7bb3e161b853b43b0bdf4453e66888eb9446bd8 v: v3

---
 [refs]                       |  2 +-
 trunk/fs/btrfs/super.c       | 15 ++++++---------
 trunk/fs/btrfs/transaction.c | 12 +++++++++++-
 trunk/fs/btrfs/transaction.h |  1 +
 4 files changed, 19 insertions(+), 11 deletions(-)

diff --git a/[refs] b/[refs]
index a7b4eb0f5be1..002819381e3d 100644
--- a/[refs]
+++ b/[refs]
@@ -1,2 +1,2 @@
 ---
-refs/heads/master: b3ae244e7174d981c09ad7a6a68e7909d600aaca
+refs/heads/master: 60376ce4a8396bc5cd777be05b6a9bf044520f42
diff --git a/trunk/fs/btrfs/super.c b/trunk/fs/btrfs/super.c
index 867e8e799dea..903ab2d7068a 100644
--- a/trunk/fs/btrfs/super.c
+++ b/trunk/fs/btrfs/super.c
@@ -854,16 +854,13 @@ int btrfs_sync_fs(struct super_block *sb, int wait)
 
 	btrfs_wait_ordered_extents(root, 0, 0);
 
-	spin_lock(&fs_info->trans_lock);
-	if (!fs_info->running_transaction) {
-		spin_unlock(&fs_info->trans_lock);
-		return 0;
-	}
-	spin_unlock(&fs_info->trans_lock);
-
-	trans = btrfs_join_transaction(root);
-	if (IS_ERR(trans))
+	trans = btrfs_join_transaction_freeze(root);
+	if (IS_ERR(trans)) {
+		/* Frozen, don't bother */
+		if (PTR_ERR(trans) == -EPERM)
+			return 0;
 		return PTR_ERR(trans);
+	}
 	return btrfs_commit_transaction(trans, root);
 }
 
diff --git a/trunk/fs/btrfs/transaction.c b/trunk/fs/btrfs/transaction.c
index c01dec70c960..e4bfac8d54b8 100644
--- a/trunk/fs/btrfs/transaction.c
+++ b/trunk/fs/btrfs/transaction.c
@@ -272,6 +272,7 @@ enum btrfs_trans_type {
 	TRANS_JOIN,
 	TRANS_USERSPACE,
 	TRANS_JOIN_NOLOCK,
+	TRANS_JOIN_FREEZE,
 };
 
 static int may_wait_transaction(struct btrfs_root *root, int type)
@@ -341,7 +342,11 @@ static struct btrfs_trans_handle *start_transaction(struct btrfs_root *root,
 	if (!h)
 		return ERR_PTR(-ENOMEM);
 
-	sb_start_intwrite(root->fs_info->sb);
+	if (!__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);
+	}
 
 	if (may_wait_transaction(root, type))
 		wait_current_trans(root);
@@ -424,6 +429,11 @@ struct btrfs_trans_handle *btrfs_start_ioctl_transaction(struct btrfs_root *root
 	return start_transaction(root, 0, TRANS_USERSPACE, 0);
 }
 
+struct btrfs_trans_handle *btrfs_join_transaction_freeze(struct btrfs_root *root)
+{
+	return start_transaction(root, 0, TRANS_JOIN_FREEZE, 0);
+}
+
 /* wait for a transaction commit to be fully complete */
 static noinline void wait_for_commit(struct btrfs_root *root,
 				    struct btrfs_transaction *commit)
diff --git a/trunk/fs/btrfs/transaction.h b/trunk/fs/btrfs/transaction.h
index b6463e128048..fbf8313b9d67 100644
--- a/trunk/fs/btrfs/transaction.h
+++ b/trunk/fs/btrfs/transaction.h
@@ -102,6 +102,7 @@ struct btrfs_trans_handle *btrfs_start_transaction_noflush(
 					struct btrfs_root *root, int num_items);
 struct btrfs_trans_handle *btrfs_join_transaction(struct btrfs_root *root);
 struct btrfs_trans_handle *btrfs_join_transaction_nolock(struct btrfs_root *root);
+struct btrfs_trans_handle *btrfs_join_transaction_freeze(struct btrfs_root *root);
 struct btrfs_trans_handle *btrfs_start_ioctl_transaction(struct btrfs_root *root);
 int btrfs_wait_for_commit(struct btrfs_root *root, u64 transid);
 int btrfs_write_and_wait_transaction(struct btrfs_trans_handle *trans,