From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S933090AbdKGDRL (ORCPT ); Mon, 6 Nov 2017 22:17:11 -0500 Received: from szxga04-in.huawei.com ([45.249.212.190]:9966 "EHLO szxga04-in.huawei.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932452AbdKGDRJ (ORCPT ); Mon, 6 Nov 2017 22:17:09 -0500 Subject: Re: [PATCH v2] f2fs: add bug_on when f2fs_gc even fails to get one victim To: Jaegeuk Kim CC: , , , , , , , References: <1507729864-118702-1-git-send-email-yunlong.song@huawei.com> <1507901500-162168-1-git-send-email-yunlong.song@huawei.com> <20171103034402.GC11335@jaegeuk-macbookpro.roam.corp.google.com> <3b26badb-c34e-3c2d-74a2-26ecef1f64ff@huawei.com> <20171107023835.GG88544@jaegeuk-macbookpro.roam.corp.google.com> <20171107024058.GH88544@jaegeuk-macbookpro.roam.corp.google.com> From: Yunlong Song Message-ID: Date: Tue, 7 Nov 2017 11:16:03 +0800 User-Agent: Mozilla/5.0 (Windows NT 6.1; WOW64; rv:52.0) Gecko/20100101 Thunderbird/52.2.1 MIME-Version: 1.0 In-Reply-To: <20171107024058.GH88544@jaegeuk-macbookpro.roam.corp.google.com> Content-Type: text/plain; charset="utf-8"; format=flowed Content-Transfer-Encoding: 7bit Content-Language: en-US X-Originating-IP: [10.111.220.140] X-CFilter-Loop: Reflected X-Mirapoint-Virus-RAPID-Raw: score=unknown(0), refid=str=0001.0A020206.5A0125A3.0075,ss=1,re=0.000,recu=0.000,reip=0.000,cl=1,cld=1,fgs=0, ip=0.0.0.0, so=2014-11-16 11:51:01, dmn=2013-03-21 17:37:32 X-Mirapoint-Loop-Id: 20c7a0107845dfff9443a1dc0a088d9f Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Because I find that some out-of-free problem is caused by the failure of get victim target. For example, chao has pointed out that he has found out a bug when adding this bug_on last week. On 2017/11/7 10:40, Jaegeuk Kim wrote: > On 11/06, Jaegeuk Kim wrote: >> On 11/06, Yunlong Song wrote: >>> Agree. >>> >>> On 2017/11/3 11:44, Jaegeuk Kim wrote: >>>> On 10/13, Yunlong Song wrote: >>>>> This can help us to debug on some corner case. >>>>> >>>>> Signed-off-by: Yunlong Song >>>>> Signed-off-by: Chao Yu >>>>> --- >>>>> fs/f2fs/gc.c | 6 +++++- >>>>> 1 file changed, 5 insertions(+), 1 deletion(-) >>>>> >>>>> diff --git a/fs/f2fs/gc.c b/fs/f2fs/gc.c >>>>> index 197ebf4..2b03202 100644 >>>>> --- a/fs/f2fs/gc.c >>>>> +++ b/fs/f2fs/gc.c >>>>> @@ -986,6 +986,7 @@ int f2fs_gc(struct f2fs_sb_info *sbi, bool sync, >>>>> .ilist = LIST_HEAD_INIT(gc_list.ilist), >>>>> .iroot = RADIX_TREE_INIT(GFP_NOFS), >>>>> }; >>>>> + bool need_fggc = false; >>>>> trace_f2fs_gc_begin(sbi->sb, sync, background, >>>>> get_pages(sbi, F2FS_DIRTY_NODES), >>>>> @@ -1018,8 +1019,10 @@ int f2fs_gc(struct f2fs_sb_info *sbi, bool sync, >>>>> if (ret) >>>>> goto stop; >>>>> } >>>>> - if (has_not_enough_free_secs(sbi, 0, 0)) >>>>> + if (has_not_enough_free_secs(sbi, 0, 0)) { >>>>> gc_type = FG_GC; >>>>> + need_fggc = true; >>>>> + } >>>>> } >>>>> /* f2fs_balance_fs doesn't need to do BG_GC in critical path. */ >>>>> @@ -1028,6 +1031,7 @@ int f2fs_gc(struct f2fs_sb_info *sbi, bool sync, >>>>> goto stop; >>>>> } >>>>> if (!__get_victim(sbi, &segno, gc_type)) { >>>>> + f2fs_bug_on(sbi, !total_freed && need_fggc); >>>> Just like this? >>> That's OK. >> I'm not quite sure whether this is really a bug_on case. >> Let me make it WARN_ON() for debugging purpose first. > BTW, why is this the special case where BG_GC detects FG_GC? > >> Thanks, >> >>>> f2fs_bug_on(sbi, !total_freed && !sync && gc_type == FG_GC); >>>> >>>>> ret = -ENODATA; >>>>> goto stop; >>>>> } >>>>> -- >>>>> 1.8.5.2 >>>> . >>>> >>> -- >>> Thanks, >>> Yunlong Song >>> > . > -- Thanks, Yunlong Song