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 A51F434136B for ; Wed, 17 Sep 2025 15:59:25 +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=1758124765; cv=none; b=paADew6EmgK0wpebo5xbfAJ2DNkcwQYJ27a3EKcMDzglPHnzf/d1cQJ189xwn5q5os1lv9NgCf6QvLnFGN5v8gY85ULq4aUNJ6T3xwp+wLk7vhsQ/aJLilQO7tC+mpUHFreIljEX3VJpDojT4anafjVlr1AZkM8uMtnCBOoAda4= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1758124765; c=relaxed/simple; bh=NnGX677nwdyHGZdxlN31q3yooL9zbXMipdVwiJ+dzBk=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=NWcTwQRM9tMfNMWjihGb+Absu99VpKs/UinDTUHBvH4cJtBUWZb/KThpgGeSEJuUJyZqAL3KO8Pa7MeESbw/R9R+vAqiQrExdSBcKJ9uwFi9ek7Ag5c08Z5F5Pelh5push2s2BXuS0kHzFri3GfIfmu4EnJFnlvSoZm/mclWI0s= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=q5M0aTe4; 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="q5M0aTe4" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 3BC55C4CEE7; Wed, 17 Sep 2025 15:59:25 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1758124765; bh=NnGX677nwdyHGZdxlN31q3yooL9zbXMipdVwiJ+dzBk=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=q5M0aTe4F3gwnP33KkGj3X8l9LNtVvODxOO439YyMDX8reXD3J2xZQKP2LPN80SUN QTeoMVUo+TBPRblP8kq9PZv3voN3GLMYqEPMapXyBniyJFmT5OEBu/TS8j7Ndvy779 crFuKVgbx8LSbXpNeHsnZ+hHEzY+cfYIhCoNkYLJdNByCAhgmI6C0CMXPglVjy3ZGW f4z+3adIG8moNfUJ/zvM+4gpd5Kc5bNF2EBoD8lGnD7lfCF0ntXGKUxgnpOM3tY665 LeBhLS2TIZGSIfBGTiHv8Yo3B8lSbyg4/x8nVjs0ssRxrHfM2sSCujVc5JXA9yVmHX vv8NLMVkpcDlA== Date: Wed, 17 Sep 2025 15:59:23 +0000 From: Jaegeuk Kim To: wangzijie Cc: chao@kernel.org, linux-f2fs-devel@lists.sourceforge.net, linux-kernel@vger.kernel.org, bintian.wang@honor.com, feng.han@honor.com Subject: Re: [f2fs-dev] [PATCH v3 1/2] f2fs: fix zero-sized extent for precache extents Message-ID: References: <20250917023622.516052-1-wangzijie1@honor.com> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20250917023622.516052-1-wangzijie1@honor.com> On 09/17, wangzijie wrote: > Script to reproduce: > f2fs_io write 1 0 1881 rand dsync testfile > f2fs_io fallocate 0 7708672 4096 testfile > f2fs_io write 1 1881 1 rand buffered testfile > fsync testfile > umount > mount > f2fs_io precache_extents testfile > > When the 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 > > During precache_extents, 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 zero-sized extent: > > 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 > > > Rebased on patch[1], this patch can cover these cases to avoid zero-sized extent: > A,B,C is valid blkaddr > 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 > > [1] https://lore.kernel.org/linux-f2fs-devel/20250912081250.44383-1-chao@kernel.org/ > > Fixes: c4020b2da4c9 ("f2fs: support F2FS_IOC_PRECACHE_EXTENTS") > Signed-off-by: wangzijie > --- > Rebased on: > https://lore.kernel.org/linux-f2fs-devel/20250912081250.44383-1-chao@kernel.org/ > v2: > https://lore.kernel.org/linux-f2fs-devel/20250915035246.98055-1-wangzijie1@honor.com/ > --- > fs/f2fs/data.c | 7 ++++--- > 1 file changed, 4 insertions(+), 3 deletions(-) > > diff --git a/fs/f2fs/data.c b/fs/f2fs/data.c > index 838eae39d..7a5170b32 100644 > --- a/fs/f2fs/data.c > +++ b/fs/f2fs/data.c > @@ -1778,9 +1778,10 @@ int f2fs_map_blocks(struct inode *inode, struct f2fs_map_blocks *map, int flag) > 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) Applied with if (map->m_len > ofs) > + 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 = is_hole ? pgofs + 1 : pgofs; > -- > 2.25.1