Btrfs: don't start a new transaction when starting sync
If there is no running transaction in the fs, we needn't start a new one when
we want to start sync.
Signed-off-by: Miao Xie <miaox@cn.fujitsu.com>
Signed-off-by: Chris Mason <chris.mason@fusionio.com>
diff --git a/fs/btrfs/ioctl.c b/fs/btrfs/ioctl.c
index 5022e62..7b1f614 100644
--- a/fs/btrfs/ioctl.c
+++ b/fs/btrfs/ioctl.c
@@ -3065,16 +3065,22 @@
u64 transid;
int ret;
- trans = btrfs_start_transaction(root, 0);
- if (IS_ERR(trans))
- return PTR_ERR(trans);
+ trans = btrfs_attach_transaction(root);
+ if (IS_ERR(trans)) {
+ if (PTR_ERR(trans) != -ENOENT)
+ return PTR_ERR(trans);
+
+ /* No running transaction, don't bother */
+ transid = root->fs_info->last_trans_committed;
+ goto out;
+ }
transid = trans->transid;
ret = btrfs_commit_transaction_async(trans, root, 0);
if (ret) {
btrfs_end_transaction(trans, root);
return ret;
}
-
+out:
if (argp)
if (copy_to_user(argp, &transid, sizeof(transid)))
return -EFAULT;
diff --git a/fs/btrfs/transaction.c b/fs/btrfs/transaction.c
index bcc6b65..8db401f 100644
--- a/fs/btrfs/transaction.c
+++ b/fs/btrfs/transaction.c
@@ -1307,9 +1307,10 @@
* We've got freeze protection passed with the transaction.
* Tell lockdep about it.
*/
- rwsem_acquire_read(
- &ac->root->fs_info->sb->s_writers.lock_map[SB_FREEZE_FS-1],
- 0, 1, _THIS_IP_);
+ if (ac->newtrans->type < TRANS_JOIN_NOLOCK)
+ rwsem_acquire_read(
+ &ac->root->fs_info->sb->s_writers.lock_map[SB_FREEZE_FS-1],
+ 0, 1, _THIS_IP_);
current->journal_info = ac->newtrans;
@@ -1347,8 +1348,10 @@
* Tell lockdep we've released the freeze rwsem, since the
* async commit thread will be the one to unlock it.
*/
- rwsem_release(&root->fs_info->sb->s_writers.lock_map[SB_FREEZE_FS-1],
- 1, _THIS_IP_);
+ if (trans->type < TRANS_JOIN_NOLOCK)
+ rwsem_release(
+ &root->fs_info->sb->s_writers.lock_map[SB_FREEZE_FS-1],
+ 1, _THIS_IP_);
schedule_delayed_work(&ac->work, 0);