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

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

fs/btrfs/ioctl.c

+10 −4
Original line number Diff line number Diff line
@@ -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;

fs/btrfs/transaction.c

+8 −5
Original line number Diff line number Diff line
@@ -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);