From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (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 4E5DE235041 for ; Fri, 12 Sep 2025 03:41:19 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1757648479; cv=none; b=tzFUgrdFb/3FErjPfpPu3B5RFx28cH5SBcVhzXpaOwYj/ZjjPz2yiw0/q8FLN69BFFkP7wtHkeBML4RyZ531VhrzxhVP5L5Fbcr9dJ0S6NRsaVtRLbaOyfV1pkyKf7K/f5vE7X0v7L7nKODm9kDyBxvA7q6g5SS40Sns6SBQVTM= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1757648479; c=relaxed/simple; bh=XDwDklRFyhTQ7jpEFuln8g3jtb2GyRw7CB0tY3hlXIE=; h=Message-ID:Date:MIME-Version:Cc:Subject:To:References:From: In-Reply-To:Content-Type; b=oJbFm5AnqfPJAl7OvTL1xY4v7B0M/Q8VFx6XUN2q/jQTYoirsV+tPW9VpqHLy4yJBAP86pAXj2EUN4fKriiwRvhJvX9kqh9TSoBKRY/vVv1tfps014xlYcmVSESz5RB0TaDh/jgHrjircDZxKYKyQZdoGlP28TZXBgQ/4in8bGU= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=sCNXCSxi; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="sCNXCSxi" Received: by smtp.kernel.org (Postfix) with ESMTPSA id E7CCCC4CEF4; Fri, 12 Sep 2025 03:41:17 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1757648479; bh=XDwDklRFyhTQ7jpEFuln8g3jtb2GyRw7CB0tY3hlXIE=; h=Date:Cc:Subject:To:References:From:In-Reply-To:From; b=sCNXCSxisFb6QSyP/WoUcT62/cIWYvK/VB/grwR38wDI1Sc/zVAJwMao5k7iLDyCK o1mYGgOSrEZLBsiWQTejzn1KDItxoTx8YcZx6+91tlXzmz5LySQrWydAl8OoahZyKu 7xGsLY7GlBiHAdXzpfZ0WgYM9rjT7KWmOKZv+3C+BuOxIIG5eN68ulQcV5WpNzhdJe yFyGJEqWFfknz3ChDzIoLvivUztP9hiubrZM4nZaC3GW17vmd0yqVhUZIjNstqorS8 Z/MO/ldNHKNJukHUqo0ApITHY/ghRsevMaAfVhrWKnDNL8vLZNINON+CQzXyOotnV7 FDDbAc2SkU++w== Message-ID: <2ecb4f74-cc60-4dd4-8dc3-d4f3ff848e87@kernel.org> Date: Fri, 12 Sep 2025 11:41:22 +0800 Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Cc: chao@kernel.org, feng.han@honor.com, jaegeuk@kernel.org, linux-f2fs-devel@lists.sourceforge.net, linux-kernel@vger.kernel.org Subject: Re: [f2fs-dev] [PATCH 1/2] f2fs: fix wrong extent_info data for precache extents To: wangzijie References: <20250912033609.3033352-1-wangzijie1@honor.com> Content-Language: en-US From: Chao Yu In-Reply-To: <20250912033609.3033352-1-wangzijie1@honor.com> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 8bit On 9/12/2025 11:36 AM, wangzijie wrote: >> On 9/11/2025 5:07 PM, wangzijie wrote: >>>> On 9/10/25 21:58, wangzijie wrote: >>>>> When the data layout is like this: >>>>> dnode1: dnode2: >>>>> [0] A [0] NEW_ADDR >>>>> [1] A+1 [1] 0x0 >>>>> ... .... >>>>> [1016] A+1016 >>>>> [1017] B (B!=A+1017) [1017] 0x0 >>>>> >>>>> We can build this kind of layout by following steps(with i_extra_isize:36): >>>>> ./f2fs_io write 1 0 1881 rand dsync testfile >>>>> ./f2fs_io write 1 1881 1 rand buffered testfile >>>>> ./f2fs_io fallocate 0 7708672 4096 testfile >>>>> >>>>> And when we map first data block in dnode2, we will get wrong extent_info data: >>>>> map->m_len = 1 >>>>> ofs = start_pgofs - map->m_lblk = 1882 - 1881 = 1 >>>>> >>>>> ei.fofs = start_pgofs = 1882 >>>>> ei.len = map->m_len - ofs = 1 - 1 = 0 >>>>> >>>>> Fix it by skipping updating this kind of extent info. >>>>> >>>>> Signed-off-by: wangzijie >>>>> --- >>>>> fs/f2fs/data.c | 3 +++ >>>>> 1 file changed, 3 insertions(+) >>>>> >>>>> diff --git a/fs/f2fs/data.c b/fs/f2fs/data.c >>>>> index 7961e0ddf..b8bb71852 100644 >>>>> --- a/fs/f2fs/data.c >>>>> +++ b/fs/f2fs/data.c >>>>> @@ -1649,6 +1649,9 @@ int f2fs_map_blocks(struct inode *inode, struct f2fs_map_blocks *map, int flag) >>>>> >>>>> switch (flag) { >>>>> case F2FS_GET_BLOCK_PRECACHE: >>>>> + if (__is_valid_data_blkaddr(map->m_pblk) && >>>>> + start_pgofs - map->m_lblk == map->m_len) >>>>> + map->m_flags &= ~F2FS_MAP_MAPPED; >>>> >>>> It looks we missed to reset value for map variable in f2fs_precache_extents(), >>>> what do you think of this? >>>> >>>> --- >>>> fs/f2fs/file.c | 4 +++- >>>> 1 file changed, 3 insertions(+), 1 deletion(-) >>>> >>>> diff --git a/fs/f2fs/file.c b/fs/f2fs/file.c >>>> index 1aae4361d0a8..2b14151d4130 100644 >>>> --- a/fs/f2fs/file.c >>>> +++ b/fs/f2fs/file.c >>>> @@ -3599,7 +3599,7 @@ static int f2fs_ioc_io_prio(struct file *filp, unsigned long arg) >>>> int f2fs_precache_extents(struct inode *inode) >>>> { >>>> struct f2fs_inode_info *fi = F2FS_I(inode); >>>> - struct f2fs_map_blocks map; >>>> + struct f2fs_map_blocks map = { 0 }; >>>> pgoff_t m_next_extent; >>>> loff_t end; >>>> int err; >>>> @@ -3617,6 +3617,8 @@ int f2fs_precache_extents(struct inode *inode) >>>> >>>> while (map.m_lblk < end) { >>>> map.m_len = end - map.m_lblk; >>>> + map.m_pblk = 0; >>>> + map.m_flags = 0; >>>> >>>> f2fs_down_write(&fi->i_gc_rwsem[WRITE]); >>>> err = f2fs_map_blocks(inode, &map, F2FS_GET_BLOCK_PRECACHE); >>>> -- >>>> 2.49.0 >>>> >>>> Thanks, >>>> >>>>> goto sync_out; >>>>> case F2FS_GET_BLOCK_BMAP: >>>>> map->m_pblk = 0; >>> >>> >>> We have already reset m_flags (map->m_flags = 0) in f2fs_map_blocks(). >> >> Zijie: >> >> Oops, that's right, thanks for correcting me. >> >>> >>> I think that this bug is caused by we missed to reset m_flags when we >>> goto next_dnode in below caseļ¼š >>> >>> Data layout is something like this: >>> dnode1: dnode2: >>> [0] A [0] NEW_ADDR >>> [1] A+1 [1] 0x0 >>> ... >>> [1016] A+1016 >>> [1017] B (B!=A+1017) [1017] 0x0 >>> >>> we map the last block(valid blkaddr) in dnode1: >>> map->m_flags |= F2FS_MAP_MAPPED; >>> map->m_pblk = blkaddr(valid blkaddr); >>> map->m_len = 1; >>> then we goto next_dnode, meet the first block in dnode2(hole), goto sync_out: >>> map->m_flags & F2FS_MAP_MAPPED == true, and we make wrong blkaddr/len for extent_info. >> >> So, can you please add above explanation into commit message? that >> should be helpful for understanding the problem more clearly. >> >> Please take a look at this case w/ your patch: >> >> mkfs.f2fs -O extra_attr,compression /dev/vdb -f >> mount /dev/vdb /mnt/f2fs -o mode=lfs >> cd /mnt/f2fs >> f2fs_io write 1 0 1883 rand dsync testfile >> f2fs_io fallocate 0 7712768 4096 testfile >> f2fs_io write 1 1881 1 rand buffered testfile >> xfs_io testfile -c "fsync" >> cd / >> umount /mnt/f2fs >> mount /dev/vdb /mnt/f2fs >> f2fs_io precache_extents /mnt/f2fs/testfile >> umount /mnt/f2fs >> >> f2fs_io-733 [010] ..... 78.134136: f2fs_update_read_extent_tree_range: dev = (253,16), ino = 4, pgofs = 1882, len = 0, blkaddr = 17410, c_len = 0 >> >> I suspect we need this? >> >> @@ -1784,7 +1781,8 @@ int f2fs_map_blocks(struct inode *inode, struct f2fs_map_blocks *map, int flag) >> } >> >> if (flag == F2FS_GET_BLOCK_PRECACHE) { >> - if (map->m_flags & F2FS_MAP_MAPPED) { >> + if ((map->m_flags & F2FS_MAP_MAPPED) && >> + (map->m_len - ofs)) { >> unsigned int ofs = start_pgofs - map->m_lblk; >> >> f2fs_update_read_extent_cache_range(&dn, > > Thanks for pointing out this. Let me find a way to cover these cases and do more test. > >> BTW, I find another bug, if one blkaddr is adjcent to previous extent, >> but and it is valid, we need to set m_next_extent to pgofs rather than >> pgofs + 1. >> >> diff --git a/fs/f2fs/data.c b/fs/f2fs/data.c >> index cbf8841642c7..ac88ed68059c 100644 >> --- a/fs/f2fs/data.c >> +++ b/fs/f2fs/data.c >> @@ -1789,8 +1789,11 @@ int f2fs_map_blocks(struct inode *inode, struct f2fs_map_blocks *map, int flag) >> start_pgofs, map->m_pblk + ofs, >> map->m_len - ofs); >> } >> - if (map->m_next_extent) >> - *map->m_next_extent = pgofs + 1; >> + if (map->m_next_extent) { >> + *map->m_next_extent = pgofs; >> + if (!__is_valid_data_blkaddr(blkaddr)) >> + *map->m_next_extent += 1; >> + } >> } >> f2fs_put_dnode(&dn); > > Maybe it can be this? > if (map->m_next_extent) > *map->m_next_extent = is_hole ? pgofs + 1 : pgofs; It's better, will update, thank you. :) Thanks,