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 57FB750269 for ; Wed, 14 Aug 2024 09:50:13 +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=1723629013; cv=none; b=Ka1gxdbXqJC5zGIr0ju/RFy0n7wfPovfkVqgNX7EK8SgVTXC1FSkggLUz4QNnO/FAyOqnWpb0L7fcqjj1r4K+jBm4sFAD7I5G29z4PGutdpSd5tKE2lUWBod/zHGZ+33A9sLIu6uWud4jbW0IsPMqjvrbCwLhvf6Qd2EoLOrUvM= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1723629013; c=relaxed/simple; bh=301oXL9Be4WKrU7++f6Fb1I0bax0v9/4TZOUrpwc8EQ=; h=Message-ID:Date:MIME-Version:Subject:To:Cc:References:From: In-Reply-To:Content-Type; b=n0UGn1G/7IdVaKuPrgVaoS9+cbe5WUIENJLlv8SQX1chU8D/v4up+j8A3nR1ggLas5yBgszjW+DVr1iDueg7wYAzGq/u1oNx7Dk3NqwuwrbFRy5Ir+w3l7l69J7HjKkppe5zTYDLFJ0Tvm1YpU3rCLOe1DpIM/yYUnk4nfhpcdQ= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=UzUw+7mT; 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="UzUw+7mT" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 67578C4AF0D; Wed, 14 Aug 2024 09:50:10 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1723629012; bh=301oXL9Be4WKrU7++f6Fb1I0bax0v9/4TZOUrpwc8EQ=; h=Date:Subject:To:Cc:References:From:In-Reply-To:From; b=UzUw+7mTmb669Okkkwlh2k+AJ6DGA7yTXI2MzkMEdR+po0KDC6asCBgzLuACXYC70 YQ5I2rI2pNeY7FpSJ5HkVt0QWwZ1HlUmqStfJuLfo2u25XlDcNRULPWMyPafGQDSoL AusP6SpSMxEgoCkSn8+Uy7zQJoCxIcC5Y5uV5nD/Jg+WOD7xcPkgls9sTT9o+GE/d6 QICdIYodf3+R0zdIYA5w8DpI7it8PWa1WpNRhnMLQTquRWAecKxyBnhKOSNVR1mGXf xfb7cSoIjUUg1M0BC7Jq94T028APt0kDUr7xJaCBr+1eTcQCpaZqRXFqQ78gI4bPpB PVBb7iFbJGqdw== Message-ID: <7860b050-3948-4e23-b40f-a3df522477cd@kernel.org> Date: Wed, 14 Aug 2024 17:50:07 +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 Subject: Re: [PATCH] f2fs: avoid unused block when dio write in LFS mode To: daejun7.park@samsung.com, "jaegeuk@kernel.org" , "linux-f2fs-devel@lists.sourceforge.net" , "linux-kernel@vger.kernel.org" Cc: Seokhwan Kim , Dongjin Kim , Yonggil Song , Jaeyoon Choi , Jeuk Kim , Nayeon Kim , Siwoo Jung References: <20240801074715epcms2p788934486cd0e8090f67ed0d7cffbc91b@epcms2p7> Content-Language: en-US From: Chao Yu In-Reply-To: <20240801074715epcms2p788934486cd0e8090f67ed0d7cffbc91b@epcms2p7> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit On 2024/8/1 15:47, Daejun Park wrote: > This patch addresses the problem that when using LFS mode, unused blocks > may occur in f2fs_map_blocks() during block allocation for dio writes. > > If a new section is allocated during block allocation, it will not be > included in the map struct by map_is_mergeable() if the LBA of the I didn't get it, why below condition in map_is_mergeable() can not catch this case? Can you please explain more? if (map->m_pblk != NEW_ADDR && blkaddr == (map->m_pblk + ofs)) return true; Thanks, > allocated block is not contiguous. However, the block already allocated > in this process will remain unused due to the LFS mode. > > This patch avoids the possibility of unused blocks by escaping > f2fs_map_blocks() when allocating the last block in a section. > > Signed-off-by: Daejun Park > --- > fs/f2fs/data.c | 13 +++++++++++++ > 1 file changed, 13 insertions(+) > > diff --git a/fs/f2fs/data.c b/fs/f2fs/data.c > index b6dcb3bcaef7..b27a3f448f32 100644 > --- a/fs/f2fs/data.c > +++ b/fs/f2fs/data.c > @@ -1711,6 +1711,19 @@ int f2fs_map_blocks(struct inode *inode, struct f2fs_map_blocks *map, int flag) > dn.ofs_in_node = end_offset; > } > > + if (flag == F2FS_GET_BLOCK_DIO && f2fs_lfs_mode(sbi)) { > + int segno = GET_SEGNO(sbi, blkaddr); > + bool last_seg, last_blk; > + > + last_seg = !((segno + 1) % SEGS_PER_SEC(sbi)); > + last_blk = (f2fs_usable_blks_in_seg(sbi, segno) - 1) == > + GET_BLKOFF_FROM_SEG0(sbi, blkaddr); > + > + /* LBA of the next block to be allocated may not be contiguous. */ > + if (last_seg && last_blk) > + goto sync_out; > + } > + > if (pgofs >= end) > goto sync_out; > else if (dn.ofs_in_node < end_offset)