From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from szxga02-in.huawei.com (szxga02-in.huawei.com [45.249.212.188]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 4D44D210F4; Thu, 4 Jan 2024 11:32:00 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=quarantine dis=none) header.from=huawei.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=huawei.com Received: from mail.maildlp.com (unknown [172.19.163.174]) by szxga02-in.huawei.com (SkyGuard) with ESMTP id 4T5PYB3DcmzWlkW; Thu, 4 Jan 2024 19:31:10 +0800 (CST) Received: from dggpeml500021.china.huawei.com (unknown [7.185.36.21]) by mail.maildlp.com (Postfix) with ESMTPS id B3708140487; Thu, 4 Jan 2024 19:31:52 +0800 (CST) Received: from [10.174.177.174] (10.174.177.174) by dggpeml500021.china.huawei.com (7.185.36.21) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256) id 15.1.2507.35; Thu, 4 Jan 2024 19:31:52 +0800 Message-ID: <6c93726b-75b8-a6a6-34d3-d0f6c7a1f35d@huawei.com> Date: Thu, 4 Jan 2024 19:31:51 +0800 Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:102.0) Gecko/20100101 Thunderbird/102.1.2 Subject: Re: [PATCH v2 3/8] ext4: regenerate buddy after block freeing failed if under fc replay To: Jan Kara CC: , , , , , , , , Baokun Li References: <20231221150558.2740823-1-libaokun1@huawei.com> <20231221150558.2740823-4-libaokun1@huawei.com> <20240104103336.fjwhqiv2maezquef@quack3> Content-Language: en-US From: Baokun Li In-Reply-To: <20240104103336.fjwhqiv2maezquef@quack3> Content-Type: text/plain; charset="UTF-8"; format=flowed Content-Transfer-Encoding: 8bit X-ClientProxiedBy: dggems702-chm.china.huawei.com (10.3.19.179) To dggpeml500021.china.huawei.com (7.185.36.21) On 2024/1/4 18:33, Jan Kara wrote: > On Thu 21-12-23 23:05:53, Baokun Li wrote: >> This reverts [Fixes] under fast commit replay. When we are freeing blocks >> that have already been freed, the buddy may be corrupted, and we need to >> regenerate the buddy when the fast commit is being replayed in order to >> avoid using an corrupted buddy, since it will not mark the group block >> bitmap as corrupted at that point. > I'd rephrase the changelog as: > > This mostly reverts commit 6bd97bf273bd ("ext4: remove redundant > mb_regenerate_buddy()") and reintroduces mb_regenerate_buddy(). Based on > code in mb_free_blocks(), fast commit replay can end up marking as free > blocks that are already marked as such. This causes corruption of the > buddy bitmap so we need to regenerate it in that case. > > Otherwise the patch looks good to me so feel free to add: > > Reviewed-by: Jan Kara > > Honza Hello Honza, Happy New Year! Thank you very much for your review! This changelog looks a lot more relevant!  I will use this changelog in the next version. >> Reported-by: Jan Kara >> Fixes: 6bd97bf273bd ("ext4: remove redundant mb_regenerate_buddy()") >> Signed-off-by: Baokun Li >> --- >> fs/ext4/mballoc.c | 20 ++++++++++++++++++++ >> 1 file changed, 20 insertions(+) >> >> diff --git a/fs/ext4/mballoc.c b/fs/ext4/mballoc.c >> index a95fa6e2b0f9..f6131ba514c8 100644 >> --- a/fs/ext4/mballoc.c >> +++ b/fs/ext4/mballoc.c >> @@ -1233,6 +1233,24 @@ void ext4_mb_generate_buddy(struct super_block *sb, >> atomic64_add(period, &sbi->s_mb_generation_time); >> } >> >> +static void mb_regenerate_buddy(struct ext4_buddy *e4b) >> +{ >> + int count; >> + int order = 1; >> + void *buddy; >> + >> + while ((buddy = mb_find_buddy(e4b, order++, &count))) >> + mb_set_bits(buddy, 0, count); >> + >> + e4b->bd_info->bb_fragments = 0; >> + memset(e4b->bd_info->bb_counters, 0, >> + sizeof(*e4b->bd_info->bb_counters) * >> + (e4b->bd_sb->s_blocksize_bits + 2)); >> + >> + ext4_mb_generate_buddy(e4b->bd_sb, e4b->bd_buddy, >> + e4b->bd_bitmap, e4b->bd_group, e4b->bd_info); >> +} >> + >> /* The buddy information is attached the buddy cache inode >> * for convenience. The information regarding each group >> * is loaded via ext4_mb_load_buddy. The information involve >> @@ -1921,6 +1939,8 @@ static void mb_free_blocks(struct inode *inode, struct ext4_buddy *e4b, >> ext4_mark_group_bitmap_corrupted( >> sb, e4b->bd_group, >> EXT4_GROUP_INFO_BBITMAP_CORRUPT); >> + } else { >> + mb_regenerate_buddy(e4b); >> } >> goto done; >> } >> -- >> 2.31.1 >> Thanks again! -- With Best Regards, Baokun Li .