From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from cn.fujitsu.com ([222.73.24.84]:1039 "EHLO song.cn.fujitsu.com" rhost-flags-OK-FAIL-OK-OK) by vger.kernel.org with ESMTP id S1756621Ab3EGG14 (ORCPT ); Tue, 7 May 2013 02:27:56 -0400 Message-ID: <51889BF1.1000300@cn.fujitsu.com> Date: Tue, 07 May 2013 14:15:13 +0800 From: Wang Shilong MIME-Version: 1.0 To: Linux Btrfs CC: Jan Schmidt Subject: [PATCH] Btrfs: save us a mutex_lock usage when doing quota rescan Content-Type: text/plain; charset=UTF-8 Sender: linux-btrfs-owner@vger.kernel.org List-ID: If qgroup_rescan worker is in progress, we should ignore the extent that has not been dealt with qgroup_rescan worker,just let them dealt later otherwise we may get wrong qgroup accounting. However, we have checked this before find_all_roots() without spin_lock. When doing qgroup accounting, we don't have to check it again, because during this period,qgroup_rescan worker can deal with more extents and qgroup_rescan_extent->objectid can only go larger, so here the check is unnecessary. Just remove this check, so that we don't need hold qgroup_rescan_lock when doing qgroup accounting. Signed-off-by: Wang Shilong --- fs/btrfs/qgroup.c | 9 --------- 1 files changed, 0 insertions(+), 9 deletions(-) diff --git a/fs/btrfs/qgroup.c b/fs/btrfs/qgroup.c index d059d86..2710784 100644 --- a/fs/btrfs/qgroup.c +++ b/fs/btrfs/qgroup.c @@ -1445,15 +1445,7 @@ int btrfs_qgroup_account_ref(struct btrfs_trans_handle *trans, if (ret < 0) return ret; - mutex_lock(&fs_info->qgroup_rescan_lock); spin_lock(&fs_info->qgroup_lock); - if (fs_info->qgroup_flags & BTRFS_QGROUP_STATUS_FLAG_RESCAN) { - if (fs_info->qgroup_rescan_progress.objectid <= node->bytenr) { - ret = 0; - goto unlock; - } - } - quota_root = fs_info->quota_root; if (!quota_root) goto unlock; @@ -1492,7 +1484,6 @@ int btrfs_qgroup_account_ref(struct btrfs_trans_handle *trans, unlock: spin_unlock(&fs_info->qgroup_lock); - mutex_unlock(&fs_info->qgroup_rescan_lock); ulist_free(roots); return ret; -- 1.7.7.6