---

yaml
---
r: 332575
b: refs/heads/master
c: 9811465
h: refs/heads/master
i:
  332573: 92398b4
  332571: 9c61d8b
  332567: b7bb3e1
  332559: cd630e9
  332543: b713f64
v: v3

[refs]

@@ -1,2 +1,2 @@
 ---
-refs/heads/master: 6bbe3a9c805fcb8cd8d396dafd32078181a7cdd5
+refs/heads/master: 98114659e0d467e2c0ee6f24f2429329328fc312

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);