Commit fdef89ce authored by Filipe Manana's avatar Filipe Manana Committed by David Sterba
Browse files

btrfs: avoid starting new transaction when cleaning qgroup during subvolume drop 



At btrfs_qgroup_cleanup_dropped_subvolume() all we want to commit the
current transaction in order to have all the qgroup rfer/excl numbers up
to date. However we are using btrfs_start_transaction(), which joins the
current transaction if there is one that is not yet committing, but also
starts a new one if there is none or if the current one is already
committing (its state is >= TRANS_STATE_COMMIT_START). This later case
results in unnecessary IO, wasting time and a pointless rotation of the
backup roots in the super block.

So instead of using btrfs_start_transaction() followed by a
btrfs_commit_transaction(), use btrfs_commit_current_transaction() which
achieves our purpose and avoids starting and committing new transactions.

Reviewed-by: default avatarQu Wenruo <wqu@suse.com>
Signed-off-by: default avatarFilipe Manana <fdmanana@suse.com>
Signed-off-by: default avatarDavid Sterba <dsterba@suse.com>
parent e2f0943c

fs/btrfs/qgroup.c

+1 −5
Original line number Diff line number Diff line
@@ -1880,11 +1880,7 @@ int btrfs_qgroup_cleanup_dropped_subvolume(struct btrfs_fs_info *fs_info, u64 su 
	 * Commit current transaction to make sure all the rfer/excl numbers

	 * get updated.

	 */

	trans = btrfs_start_transaction(fs_info->quota_root, 0);

	if (IS_ERR(trans))

		return PTR_ERR(trans);



	ret = btrfs_commit_transaction(trans);

	ret = btrfs_commit_current_transaction(fs_info->quota_root);

	if (ret < 0)

		return ret;