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 218302EB1F for ; Tue, 5 Nov 2024 10:39:31 +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=1730803172; cv=none; b=e2n6XIj5FQnwyv2masYA/mOI21SXdrMQThnboZWhym32kpO1iCPiN8u9gqdAtud7KAzT4Vn0Q2Y2bV72+Btta6FBa5iBwgTb6iusMI7StnUH5J00I9UxmIh4G2x6PnQU980hpCsSonxUS0JvrUfVffLa72+GAdKafa5edFOMWP4= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1730803172; c=relaxed/simple; bh=3/xAX4B7Wj8zuIXV6aOmApU6XauE3kcnSEIfW53M1Gg=; h=Message-ID:Date:MIME-Version:Cc:Subject:To:References:From: In-Reply-To:Content-Type; b=Y88yc9Gq/0OXmWkkWQQTk8I0DlXGfA1qjAvAL2OsBmBMSoIcIVdcQQttwPjLcjTSpH7ql7OCLY3TrFaOQ+pMt5pNO4HzGKxNf/LMlOsuyYB41/AdsMRyKca/TMCtEz2MeHr70tGn90c35v9+eyQL2yDOlA8klYVjv1YM1cFWLVk= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=rnxecJvq; 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="rnxecJvq" Received: by smtp.kernel.org (Postfix) with ESMTPSA id D43ABC4CECF; Tue, 5 Nov 2024 10:39:29 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1730803171; bh=3/xAX4B7Wj8zuIXV6aOmApU6XauE3kcnSEIfW53M1Gg=; h=Date:Cc:Subject:To:References:From:In-Reply-To:From; b=rnxecJvql01bCuAChTZME/JJL8upUBjFgdncpmNuW8lwhBv+cJRaGBj+giiHbtAeu B/wEBXO38BlW/kTBqOIfRVEM7a+32z84uHjUCQygS3Hb4hsk3C0OTcUJTsRAR1ZDwi q7JiA5v0uN880PYCw0MQb5a2IZlsCzM3U3s1fNuVN2JNtODySh+7lHjCJvAM3VmpMM 3IHAAv3t1SDDp8aUWq/5w5Cvlby0F5pbEPR6TwsfIxFSP7XpY0qiO/1u8s7b0xBO1h mPn0JaGVkMKFSAkBtOVyFRmzk9fd32xKVN+Tf8MHIGCsN60oHq6GtqZbCz9UpAKn+m zZF+fIhXrgGQQ== Message-ID: <22873055-370b-4240-83ff-96bcfa91413a@kernel.org> Date: Tue, 5 Nov 2024 18:39:27 +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 Yu , Zhiguo Niu , jaegeuk@kernel.org, linux-f2fs-devel@lists.sourceforge.net, linux-kernel@vger.kernel.org, ke.wang@unisoc.com, Hao_hao.Wang@unisoc.com Subject: Re: [PATCH V2] f2fs: fix to adjust appropriate length for fiemap To: Zhiguo Niu References: <1730685372-2995-1-git-send-email-zhiguo.niu@unisoc.com> Content-Language: en-US From: Chao Yu In-Reply-To: Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 8bit On 2024/11/5 15:28, Zhiguo Niu wrote: > Chao Yu 于2024年11月5日周二 15:04写道： >> >> On 2024/11/4 9:56, Zhiguo Niu wrote: >>> If user give a file size as "length" parameter for fiemap >>> operations, but if this size is non-block size aligned, >>> it will show 2 segments fiemap results even this whole file >>> is contiguous on disk, such as the following results: >>> >>> ./f2fs_io fiemap 0 19034 ylog/analyzer.py >>> Fiemap: offset = 0 len = 19034 >>> logical addr. physical addr. length flags >>> 0 0000000000000000 0000000020baa000 0000000000004000 00001000 >>> 1 0000000000004000 0000000020bae000 0000000000001000 00001001 >>> >>> after this patch: >>> ./f2fs_io fiemap 0 19034 ylog/analyzer.py >>> Fiemap: offset = 0 len = 19034 >>> logical addr. physical addr. length flags >>> 0 0000000000000000 00000000315f3000 0000000000005000 00001001 >>> >>> Signed-off-by: Zhiguo Niu >>> --- >>> V2: correct commit msg according to Chao's questions >>> f2fs_io has been modified for testing, the length for fiemap is >>> real file size, not block number >>> --- >>> fs/f2fs/data.c | 4 ++-- >>> 1 file changed, 2 insertions(+), 2 deletions(-) >>> >>> diff --git a/fs/f2fs/data.c b/fs/f2fs/data.c >>> index 306b86b0..9fc229d 100644 >>> --- a/fs/f2fs/data.c >>> +++ b/fs/f2fs/data.c >>> @@ -1966,8 +1966,8 @@ int f2fs_fiemap(struct inode *inode, struct fiemap_extent_info *fieinfo, >>> goto out; >>> } >>> >>> - if (bytes_to_blks(inode, len) == 0) >>> - len = blks_to_bytes(inode, 1); >>> + if (len & (blks_to_bytes(inode, 1) - 1)) >>> + len = round_up(len, blks_to_bytes(inode, 1)); >> >> How do you think of getting rid of above alignment for len? >> >>> >>> start_blk = bytes_to_blks(inode, start); >>> last_blk = bytes_to_blks(inode, start + len - 1); >> >> And round up end position w/: >> >> last_blk = bytes_to_blks(inode, round_up(start + len - 1, F2FS_BLKSIZE)); > Hi Chao, > I think this will change the current code logic > ------------- > if (start_blk > last_blk) > goto out; > ------------- > for example, a file with size 19006, but the length from the user is 16384. > before this modification, last_blk = bytes_to_blks(inode, start + > len - 1) = (inode, 16383) = 3 > after the first f2fs_map_blocks(). start_blk change to be 4, > after the second f2fs_map_blocks(), fiemap_fill_nex_exten will be > called to fill user parameter and then > will goto out because start_blk > last_blk, then fiemap flow finishes. > but after this modification, last_blk will be 4 > will do f2fs_map_blocks() until reach the max_file_blocks(inode) Yes, you're right, however, w/ this patch, it may change last_blk, e.g. xfs_io file -c "fiemap -v 0 19006" vs xfs_io file -c "fiemap -v 2 19006" start_blk and last_blk will be: 0, 4 and 0, 5. Should we round_up len after start_blk & last_blk calculation? Thanks, > thanks！ >> >> Thanks, >>