Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752061AbdC0ISu (ORCPT ); Mon, 27 Mar 2017 04:18:50 -0400 Received: from szxga03-in.huawei.com ([45.249.212.189]:4461 "EHLO dggrg03-dlp.huawei.com" rhost-flags-OK-FAIL-OK-FAIL) by vger.kernel.org with ESMTP id S1751465AbdC0ISn (ORCPT ); Mon, 27 Mar 2017 04:18:43 -0400 Subject: Re: [f2fs-dev] [PATCH 1/5] f2fs: relax node version check for victim data in gc To: Jaegeuk Kim References: <20170325075933.21072-1-jaegeuk@kernel.org> <2b848126-cf2c-2145-083a-ae5ca77356b6@huawei.com> <20170325212742.GA24857@jaegeuk.local> CC: , , From: Chao Yu Message-ID: Date: Mon, 27 Mar 2017 16:18:26 +0800 User-Agent: Mozilla/5.0 (Windows NT 6.1; WOW64; rv:45.0) Gecko/20100101 Thunderbird/45.0 MIME-Version: 1.0 In-Reply-To: <20170325212742.GA24857@jaegeuk.local> Content-Type: text/plain; charset="windows-1252" Content-Transfer-Encoding: 7bit X-Originating-IP: [10.134.22.195] X-CFilter-Loop: Reflected X-Mirapoint-Virus-RAPID-Raw: score=unknown(0), refid=str=0001.0A090202.58D8CAD5.0079,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: 11b0b0dd1f87a1f618be9ccb544851c3 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2078 Lines: 70 On 2017/3/26 5:27, Jaegeuk Kim wrote: > On 03/25, Chao Yu wrote: >> Hi Jaegeuk, >> >> On 2017/3/25 15:59, Jaegeuk Kim wrote: >>> - has_not_enough_free_secs >>> node_secs: 0 dent_secs: 0 freed:0 free_segments:103 reserved:104 >>> >>> - f2fs_gc >>> - get_victim_by_default >>> alloc_mode 0, gc_mode 1, max_search 2672, offset 4654, ofs_unit 1 >>> >>> - do_garbage_collect >>> start_segno 3976, end_segno 3977 type 0 >>> >>> - is_alive >>> nid 22797, blkaddr 2131882, ofs_in_node 0, version 0x8/0x0 >>> >>> - gc_data_segment 766, segno 3976, block 512/426 not alive >>> >>> So, this patch fixes subtle corrupted case where node version does not match >>> to summary version which results in infinite loop by gc. >>> >>> Reported-by: Yunlei He >>> Signed-off-by: Jaegeuk Kim >>> --- >>> fs/f2fs/gc.c | 6 ++++-- >>> 1 file changed, 4 insertions(+), 2 deletions(-) >>> >>> diff --git a/fs/f2fs/gc.c b/fs/f2fs/gc.c >>> index 939be88a8833..bbeee41aaf73 100644 >>> --- a/fs/f2fs/gc.c >>> +++ b/fs/f2fs/gc.c >>> @@ -551,8 +551,10 @@ static bool is_alive(struct f2fs_sb_info *sbi, struct f2fs_summary *sum, >>> get_node_info(sbi, nid, dni); >>> >>> if (sum->version != dni->version) { >> >> If the node was been truncated, we will increase its version number, since it >> was been truncated, so it will never be writebacked to storage, so the version >> in summary will not be updated. > > That's covered by node page lock, so we shouldn't be reached out to this point. > Let's think more about this. Yes, agreed. ;) Thanks, > > Thanks, > >> So this case can happen, shouldn't we just set SBI_NEED_FSCK for the case: >> sum->version != dni->version - 1 >> >> Thanks, >> >>> - f2fs_put_page(node_page, 1); >>> - return false; >>> + f2fs_msg(sbi->sb, KERN_WARNING, >>> + "%s: valid data with mismatched node version.", >>> + __func__); >>> + set_sbi_flag(sbi, SBI_NEED_FSCK); >>> } >>> >>> *nofs = ofs_of_node(node_page); >>> > > . >