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 C178318FC75 for ; Wed, 6 Nov 2024 02:16:24 +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=1730859384; cv=none; b=BJrEKInLB3LoY7RKbkM3NQCzIiorVzM07N/ecyKDvIl9PzkViJ2On4cGvYjp/6QGae3ckkQAd6ArfonhSo4gU9zxj89pKT9YfJB4XE4q2eeCT8SIYSkXrAsMrNNInIfV1hUip2rL0e+dBIWZcKw7OyKS8+HTotknNteNwipc16U= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1730859384; c=relaxed/simple; bh=06l34PWhvl4tdNiJSYbSZO4mr1xYv8cmwY77xvFqw2Q=; h=Message-ID:Date:MIME-Version:Cc:Subject:To:References:From: In-Reply-To:Content-Type; b=mKJxDnnXRS03FkYTTHuP77ybkdL00j3i0Mka3qhfflp11pDTQGM1aHNLVfHYVQ67UiCcrcxJHeF3UcbSgTrRMKEo2Juqw3vucgmwCS1L0cMpEcjzvag0HZ3Ikpi+EZRPL02BE4degI1MTjESCDnADNKkYY6vFuVD8ooreFM7O4o= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=dSi0Z35M; 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="dSi0Z35M" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 9C423C4CED1; Wed, 6 Nov 2024 02:16:22 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1730859384; bh=06l34PWhvl4tdNiJSYbSZO4mr1xYv8cmwY77xvFqw2Q=; h=Date:Cc:Subject:To:References:From:In-Reply-To:From; b=dSi0Z35MYmjitvBnV1jBnhBWpPchp+wG3KFIZXuY8ya7S6M9P+DXegErXesVIvIBn TgKj/SVY0vHbOh7TF1lgZnWeffWqby6TLMK1YsVwTojrMA8XFO1g+R7aCJTr5/ta9R WIAoj4ekSnvQjVLmZ5gcrdFCqjeiw67/COz2TBUo+Cwu2EzD3AqfsPg28UbQ9b/ys4 TsYQd7p5i1/Hp6vnyIE4+P7azDxOcnov69XbBzS4U1YOtIgWRP1NVh46mH/LDnuW0X Xn65pf2fCjxq5IYe81/c8azbLHykJSgSg5t9+o5HmWFI8HNOHqeS4xZruqZIMcTh2q xq0/ic6Ai9GSg== Message-ID: <9199e9fc-7b5b-4069-b79b-65ba5ae1b0f6@kernel.org> Date: Wed, 6 Nov 2024 10:16:20 +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> <22873055-370b-4240-83ff-96bcfa91413a@kernel.org> 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 19:02, Zhiguo Niu wrote: > Chao Yu 于2024年11月5日周二 18:39写道： >> >> 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. > Hi Chao, > yes, but w/o this patch , the original code still has the same situation?? > for example > xfs_io file -c "fiemap -v 0 16384" vs xfs_io file -c "fiemap -v 2 16384" > start_blk and last_blk will be: 0, 3 and 0, 4. For the case "fiemap -v 2 19006", offset is 2, and length is 19006, so last_offset is 19008, and last_blk should be 4 rather than 5, right? And for you case, it calculates last_blk correctly. Thanks, > but overall last_blk will change loop counts but has not affect on the results. >> >> Should we round_up len after start_blk & last_blk calculation? > I thinks it is ok ,but just a little bit redundant with the following > handling about len. > > if (bytes_to_blks(inode, len) == 0) > len = blks_to_bytes(inode, 1); > > Based on the above situation, > do you have any other good suggestions? ^^ > thanks! > >> >> Thanks, >> >>> thanks！ >>>> >>>> Thanks, >>>> >>