[PATCH 11/11] Btrfs: Add ACCESS_ONCE() to transaction->abort accesses

[Miao Xie <miaox@cn.fujitsu.com>]

We may access and update transaction->abort on the different CPUs without lock,
so we need ACCESS_ONCE() wrapper to make sure we can get the new value.

Signed-off-by: Miao Xie <miaox@cn.fujitsu.com>
---
 fs/btrfs/super.c       | 2 +-
 fs/btrfs/transaction.c | 9 ++++-----
 2 files changed, 5 insertions(+), 6 deletions(-)

diff --git a/fs/btrfs/super.c b/fs/btrfs/super.c
index f714379..0d88513 100644
--- a/fs/btrfs/super.c
+++ b/fs/btrfs/super.c
@@ -267,7 +267,7 @@ void __btrfs_abort_transaction(struct btrfs_trans_handle *trans,
 			     function, line, errstr);
 		return;
 	}
-	trans->transaction->aborted = errno;
+	ACCESS_ONCE(trans->transaction->aborted) = errno;
 	__btrfs_std_error(root->fs_info, function, line, errno, NULL);
 }
 /*
diff --git a/fs/btrfs/transaction.c b/fs/btrfs/transaction.c
index a950d48..ee6cf27 100644
--- a/fs/btrfs/transaction.c
+++ b/fs/btrfs/transaction.c
@@ -1468,11 +1468,6 @@ int btrfs_commit_transaction(struct btrfs_trans_handle *trans,
 		goto cleanup_transaction;
 	}
 
-	if (cur_trans->aborted) {
-		ret = cur_trans->aborted;
-		goto cleanup_transaction;
-	}
-
 	/* make a pass through all the delayed refs we have so far
 	 * any runnings procs may add more while we are here
 	 */
@@ -1574,6 +1569,10 @@ int btrfs_commit_transaction(struct btrfs_trans_handle *trans,
 	wait_event(cur_trans->writer_wait,
 		   atomic_read(&cur_trans->num_writers) == 1);
 
+	if (ACCESS_ONCE(cur_trans->aborted)) {
+		ret = cur_trans->aborted;
+		goto cleanup_transaction;
+	}
 	/*
 	 * the reloc mutex makes sure that we stop
 	 * the balancing code from coming in and moving
-- 
1.7.11.7