From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail.kernel.org ([198.145.29.99]:36448 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751783AbdJNAOr (ORCPT ); Fri, 13 Oct 2017 20:14:47 -0400 Subject: Re: [f2fs-dev] [PATCH v2] f2fs: update dirty status for CURSEG as well To: Yunlong Song , jaegeuk@kernel.org, yuchao0@huawei.com, yunlong.song@icloud.com Cc: linux-fsdevel@vger.kernel.org, miaoxie@huawei.com, linux-kernel@vger.kernel.org, linux-f2fs-devel@lists.sourceforge.net References: <1507728318-113117-1-git-send-email-yunlong.song@huawei.com> <1507900897-156286-1-git-send-email-yunlong.song@huawei.com> From: Chao Yu Message-ID: <72f5511f-dcd4-939b-661f-f333738ee691@kernel.org> Date: Sat, 14 Oct 2017 08:14:35 +0800 MIME-Version: 1.0 In-Reply-To: <1507900897-156286-1-git-send-email-yunlong.song@huawei.com> Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 7bit Sender: linux-fsdevel-owner@vger.kernel.org List-ID: On 2017/10/13 21:21, Yunlong Song wrote: > Without this patch, it will cause all the free segments using up in some > corner case. For example, there are 100 segments, and 20 of them are > reserved for ovp. If 79 segments are full of data, segment 80 becomes > CURSEG segment, write 512 blocks and then delete 511 blocks. Since it is > CURSEG segment, the __locate_dirty_segment will not update its dirty > status. Then the dirty_segments(sbi) is 0, f2fs_gc will fail to > get_victim, and f2fs_balance_fs will fail to trigger gc action. After > f2fs_balance_fs returns, f2fs can continue to write data to segment 81. > Again, segment 81 becomes CURSEG segment, write 512 blocks and delete > 511 blocks, the dirty_segments(sbi) is 0 and f2fs_gc fail again. This > can finally use up all the free segments and cause panic. Look into this patch again, I found refresh_sit_entry is called after ->allocate_segment, so if all 512 blocks were allocated, log header should have been moved to another segment, so locate_dirty_segment in refresh_sit_entry should update dirty status of previous segment correctly, anything I'm missing? Thanks, > > Signed-off-by: Yunlong Song > --- > fs/f2fs/segment.c | 4 ++-- > 1 file changed, 2 insertions(+), 2 deletions(-) > > diff --git a/fs/f2fs/segment.c b/fs/f2fs/segment.c > index bfbcff8..0fce076 100644 > --- a/fs/f2fs/segment.c > +++ b/fs/f2fs/segment.c > @@ -687,7 +687,7 @@ static void __locate_dirty_segment(struct f2fs_sb_info *sbi, unsigned int segno, > struct dirty_seglist_info *dirty_i = DIRTY_I(sbi); > > /* need not be added */ > - if (IS_CURSEG(sbi, segno)) > + if (IS_CURSEG(sbi, segno) && dirty_type == PRE) > return; > > if (!test_and_set_bit(segno, dirty_i->dirty_segmap[dirty_type])) > @@ -737,7 +737,7 @@ static void locate_dirty_segment(struct f2fs_sb_info *sbi, unsigned int segno) > struct dirty_seglist_info *dirty_i = DIRTY_I(sbi); > unsigned short valid_blocks; > > - if (segno == NULL_SEGNO || IS_CURSEG(sbi, segno)) > + if (segno == NULL_SEGNO) > return; > > mutex_lock(&dirty_i->seglist_lock); >