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 900732EBDDC for ; Fri, 12 Sep 2025 10:38:56 +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=1757673536; cv=none; b=kngHm1npgwBIgKWlVtjOiKCGQ1Aww9Wu7chD7Ug/4MtqYkeKA5pIDygk5tEurC7qfoJHKBTz0rqFr5GGlRClU3PK2R1pn+Alfw2ZubUbjUWmBDQyQ5puIvt/QGsOMnTjd6CuiUAflK1VbssOXv/cPjKrYWFubP16cpKhAV+U5K8= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1757673536; c=relaxed/simple; bh=iPCFZZNGeEXP4VXVwEOl0dkNG1owk4NNFMYpbjH9kgI=; h=Message-ID:Date:MIME-Version:Cc:Subject:To:References:From: In-Reply-To:Content-Type; b=nIG0Jbjf23rxnS4LHGgEh47d2EIaGQCWgB2F4f/C5jylTy0I77JnhrM3IU9+jqiLuiw5bU+KnQH5mlL7rQahKOApGAdyb7IOM/qimHjCpmZGiL3KBDcTrsCfkgojCYbNGd+PWtWeAU9/0hrf69iaCqWqlgOxLFg5DED+SusZOuU= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=PLGckd0Z; 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="PLGckd0Z" Received: by smtp.kernel.org (Postfix) with ESMTPSA id DC7CBC4CEFA; Fri, 12 Sep 2025 10:38:54 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1757673536; bh=iPCFZZNGeEXP4VXVwEOl0dkNG1owk4NNFMYpbjH9kgI=; h=Date:Cc:Subject:To:References:From:In-Reply-To:From; b=PLGckd0ZoLa+xWUPJPCbrNyz6t6ZLFWHFVE8ilK4gAJPx0557r6mT373s+3OsWxVT 7r33UTrmNbBLYCNfbEcWM48Lbx1GrI/K0V4mweZRSdpYZBZulS9mkSdUsMIQ5MjFDb v9JKc2KgBTW+RSPyR+bXpaGcAp10Ml0lUv7jENmPx4IObMVkrUIbq/c0JocNJN4n+W MsMT/nkYH4UE+9G2qI/cqf68M2V7oB01u4rnoPPU0FZBHIn8xQUno3ln+VY5Eb21ga 1JmcOlJoFRNuCD/p70lNwKs5zOurQXVuFhtKhsGdK6cH5ALNEKaKMbQkDWQK+ZaECj O3pEtE/EVA56Q== Message-ID: <6464ded0-b25e-4ce8-a05b-6caa394fbe63@kernel.org> Date: Fri, 12 Sep 2025 18:38:58 +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: <2ecb4f74-cc60-4dd4-8dc3-d4f3ff848e87@kernel.org> <20250912100650.3594565-1-wangzijie1@honor.com> Content-Language: en-US From: Chao Yu In-Reply-To: <20250912100650.3594565-1-wangzijie1@honor.com> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 8bit On 9/12/2025 6:06 PM, wangzijie wrote: >> 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, > > Hi Chao, > I test some cases with this change: > > diff --git a/fs/f2fs/data.c b/fs/f2fs/data.c > index 7961e0ddf..7093fdc95 100644 > --- a/fs/f2fs/data.c > +++ b/fs/f2fs/data.c > @@ -1777,13 +1777,13 @@ 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) { > unsigned int ofs = start_pgofs - map->m_lblk; > - > - f2fs_update_read_extent_cache_range(&dn, > - start_pgofs, map->m_pblk + ofs, > - map->m_len - ofs); > + if (map->m_len - ofs > 0) > + f2fs_update_read_extent_cache_range(&dn, > + start_pgofs, map->m_pblk + ofs, > + map->m_len - ofs); > } > if (map->m_next_extent) > - *map->m_next_extent = pgofs + 1; > + *map->m_next_extent = is_hole ? pgofs + 1 : pgofs; > } > f2fs_put_dnode(&dn); > unlock_out: > > > test cases: > > case1: > dnode1: dnode2: > [0] A [0] NEW_ADDR > [1] A+1 [1] 0x0 > ... .... > [1016] A+1016 > [1017] B (B!=A+1017) [1017] 0x0 > > case2: > dnode1: dnode2: > [0] A [0] C (C!=B+1) > [1] A+1 [1] C+1 > ... .... > [1016] A+1016 > [1017] B (B!=A+1017) [1017] 0x0 > > case3: > dnode1: dnode2: > [0] A [0] C (C!=B+2) > [1] A+1 [1] C+1 > ... .... > [1015] A+1015 > [1016] B (B!=A+1016) > [1017] B+1 [1017] 0x0 > > case4: > one blkaddr is adjcent to previous extent, and it is valid. > > And from the result, it seems this change can cover these > situations correctly. > Do we need a patch with this change? Zijie, thanks for the test. IMO, we'd better use these changes: - - f2fs_update_read_extent_cache_range(&dn, - start_pgofs, map->m_pblk + ofs, - map->m_len - ofs); + if (map->m_len - ofs > 0) + f2fs_update_read_extent_cache_range(&dn, + start_pgofs, map->m_pblk + ofs, + map->m_len - ofs); instead of 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; Can you please rebase your patchset on mine and send v2? https://lore.kernel.org/linux-f2fs-devel/20250912081250.44383-1-chao@kernel.org BTW, please add fixes line in your patch. Thanks,