From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from [59.151.112.132] ([59.151.112.132]:49097 "EHLO heian.cn.fujitsu.com" rhost-flags-FAIL-FAIL-OK-FAIL) by vger.kernel.org with ESMTP id S1755427AbbJICRT (ORCPT ); Thu, 8 Oct 2015 22:17:19 -0400 Received: from G08CNEXCHPEKD01.g08.fujitsu.local (localhost.localdomain [127.0.0.1]) by edo.cn.fujitsu.com (8.14.3/8.13.1) with ESMTP id t992GeqO022695 for ; Fri, 9 Oct 2015 10:16:41 +0800 From: Qu Wenruo To: Subject: [PATCH v2 03/23] btrfs: qgroup: Introduce new function to search most left reserve range Date: Fri, 9 Oct 2015 10:15:03 +0800 Message-ID: <1444356905-31410-1-git-send-email-quwenruo@cn.fujitsu.com> In-Reply-To: <1444356684-30162-1-git-send-email-quwenruo@cn.fujitsu.com> References: <1444356684-30162-1-git-send-email-quwenruo@cn.fujitsu.com> MIME-Version: 1.0 Content-Type: text/plain 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 c275312..c771029 100644 --- a/fs/btrfs/qgroup.c +++ b/fs/btrfs/qgroup.c @@ -2541,6 +2541,42 @@ 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 -- 2.6.1