From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from cn.fujitsu.com ([222.73.24.84]:18969 "EHLO song.cn.fujitsu.com" rhost-flags-OK-FAIL-OK-OK) by vger.kernel.org with ESMTP id S1752218AbbIBHvY (ORCPT ); Wed, 2 Sep 2015 03:51:24 -0400 Received: from localhost.localdomain (tang.cn.fujitsu.com [127.0.0.1]) by tang.cn.fujitsu.com (8.14.3/8.13.1) with ESMTP id t810XlIg023763 for ; Tue, 1 Sep 2015 08:33:52 +0800 From: Qu Wenruo To: linux-btrfs@vger.kernel.org Subject: [PATCH RFC 03/14] btrfs: qgroup: Introduce new function to search most left reserve range Date: Tue, 1 Sep 2015 08:31:43 +0800 Message-Id: <1441067515-21105-4-git-send-email-quwenruo@cn.fujitsu.com> In-Reply-To: <1441067515-21105-1-git-send-email-quwenruo@cn.fujitsu.com> References: <1441067515-21105-1-git-send-email-quwenruo@cn.fujitsu.com> Sender: linux-btrfs-owner@vger.kernel.org List-ID: Introduce the new function to search the most left reserve range in a reserve map. It provides the basis for later reserve map implement. Signed-off-by: Qu Wenruo --- fs/btrfs/qgroup.c | 36 ++++++++++++++++++++++++++++++++++++ 1 file changed, 36 insertions(+) diff --git a/fs/btrfs/qgroup.c b/fs/btrfs/qgroup.c index 2e9a93f..e19fe6a 100644 --- a/fs/btrfs/qgroup.c +++ b/fs/btrfs/qgroup.c @@ -2513,6 +2513,42 @@ btrfs_qgroup_rescan_resume(struct btrfs_fs_info *fs_info) } /* + * Return the nearest left range of given start + * No ensure about the range will cover start. + */ +static struct data_rsv_range * +find_reserve_range(struct btrfs_qgroup_data_rsv_map *map, u64 start) +{ + struct rb_node **p = &map->root.rb_node; + struct rb_node *parent = NULL; + struct rb_node *prev = NULL; + struct data_rsv_range *range = NULL; + + while (*p) { + parent = *p; + range = rb_entry(parent, struct data_rsv_range, node); + if (range->start < start) + p = &(*p)->rb_right; + else if (range->start > start) + p = &(*p)->rb_left; + else + return range; + } + + /* empty tree */ + if (!parent) + return NULL; + if (range->start <= start) + return range; + + prev = rb_prev(parent); + /* Already most left one */ + if (!prev) + return range; + return rb_entry(prev, struct data_rsv_range, node); +} + +/* * Init data_rsv_map for a given inode. * * This is needed at write time as quota can be disabled and then enabled -- 2.5.0