Commit ff7c1d33 authored by Miao Xie's avatar Miao Xie Committed by Chris Mason

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: default avatarMiao Xie <miaox@cn.fujitsu.com>
Signed-off-by: default avatarChris Mason <chris.mason@fusionio.com>
parent 9a8c28be
......@@ -3065,16 +3065,22 @@ static noinline long btrfs_ioctl_start_sync(struct btrfs_root *root,
u64 transid;
int ret;
trans = btrfs_start_transaction(root, 0);
if (IS_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;
......
......@@ -1307,6 +1307,7 @@ static void do_async_commit(struct work_struct *work)
* We've got freeze protection passed with the transaction.
* Tell lockdep about it.
*/
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_);
......@@ -1347,7 +1348,9 @@ int btrfs_commit_transaction_async(struct btrfs_trans_handle *trans,
* 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],
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);
......
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