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 E0B3418DF64 for ; Wed, 6 Nov 2024 02:40:22 +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=1730860823; cv=none; b=GVRMl9GTP9ngIf66os2+XYRasLNgrfwqLlhEYnzvlUUapXrojfZyhY7WZTuOyLVib3G/0PeJ+Oq3AHYiljk2UevaKF4yfwxmOfel1oqDzhQ87vK8PVe8DgjNha92mrdOzZL7FKU4fdfuYQUIzUSgIxIiII0bHcep8uTlotarf04= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1730860823; c=relaxed/simple; bh=8skSwEKa2BJdI+HdH5Bnq08Ua01XRXyPvb6CEc1N0+o=; h=Message-ID:Date:MIME-Version:Cc:Subject:To:References:From: In-Reply-To:Content-Type; b=r8+CZRlrFtax9dZ9WC5THhE8yASqA0LaKWXw93ixuMb+CTXsEWCyVGSRr4F8eYKSVcM4oiGnY2ys+DHm3xbsbv3ddnYU8Gw4U8ulgk6hxKE4qx437dLMI3VJ5lhItzEqQMhVpu8wiFhhxECuPmTK/tii7THUhXF51ZExovlSKOw= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=WWXLSvRT; 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="WWXLSvRT" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 8AB95C4CECF; Wed, 6 Nov 2024 02:40:20 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1730860822; bh=8skSwEKa2BJdI+HdH5Bnq08Ua01XRXyPvb6CEc1N0+o=; h=Date:Cc:Subject:To:References:From:In-Reply-To:From; b=WWXLSvRTbUiPWWKtMytVIOms90KKpuZmDWJjG5XKjv3F4uI0pAzyM1IYTigynUanc EqvLbwa86M5kudGz8nuZbG+NlUIw+TGFetghuLiPIbmCcImZIIJWIHX4oDo8zG85OF ZZYVaAMIDQDEk5EtfhRfpkGr60JvP8PoDFZnU8SJcfzM4kOgZZ0JAC/8YnhdhonLdB ylzR5W2Os02g4AWb3yH2dg3vQAMX4r+Wh7GjnKZITsn9y+jOgCsrMSYnwWATTfFCJN KVimjE8sw7F8EbIdmsRHD5z+uTdR9Fxg2AoouH2PPRFem5z7+5yePqOCbv131hqZMs lg3KzOj4JVdaQ== Message-ID: Date: Wed, 6 Nov 2024 10:40:17 +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> <9199e9fc-7b5b-4069-b79b-65ba5ae1b0f6@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 2024/11/6 10:26, Zhiguo Niu wrote: > Chao Yu 于2024年11月6日周三 10:16写道： >> >> 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? > hi Chao, > it is right w/o my patch. >> >> And for you case, it calculates last_blk correctly. > So you suggest that "Should we round_up len after start_blk & last_blk > calculation?" Zhiguo, Yes, I think alignment of len should not affect calculation of last_blk. I mean this, --- fs/f2fs/data.c | 6 +++--- include/linux/f2fs_fs.h | 3 ++- 2 files changed, 5 insertions(+), 4 deletions(-) diff --git a/fs/f2fs/data.c b/fs/f2fs/data.c index 7d1bb9518a40..cbbb956f420d 100644 --- a/fs/f2fs/data.c +++ b/fs/f2fs/data.c @@ -1967,12 +1967,12 @@ 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); - start_blk = bytes_to_blks(inode, start); last_blk = bytes_to_blks(inode, start + len - 1); + if (len & F2FS_BLKSIZE_MASK) + len = round_up(len, F2FS_BLKSIZE); + next: memset(&map, 0, sizeof(map)); map.m_lblk = start_blk; diff --git a/include/linux/f2fs_fs.h b/include/linux/f2fs_fs.h index b0b821edfd97..954e8e8344b7 100644 --- a/include/linux/f2fs_fs.h +++ b/include/linux/f2fs_fs.h @@ -24,10 +24,11 @@ #define NEW_ADDR ((block_t)-1) /* used as block_t addresses */ #define COMPRESS_ADDR ((block_t)-2) /* used as compressed data flag */ +#define F2FS_BLKSIZE_MASK (F2FS_BLKSIZE - 1) #define F2FS_BYTES_TO_BLK(bytes) ((bytes) >> F2FS_BLKSIZE_BITS) #define F2FS_BLK_TO_BYTES(blk) ((blk) << F2FS_BLKSIZE_BITS) #define F2FS_BLK_END_BYTES(blk) (F2FS_BLK_TO_BYTES(blk + 1) - 1) -#define F2FS_BLK_ALIGN(x) (F2FS_BYTES_TO_BLK((x) + F2FS_BLKSIZE - 1)) +#define F2FS_BLK_ALIGN(x) (F2FS_BYTES_TO_BLK((x) + F2FS_BLKSIZE - 1)) /* 0, 1(node nid), 2(meta nid) are reserved node id */ #define F2FS_RESERVED_NODE_NUM 3 -- 2.40.1 > Thanks >> >> 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, >>>>>> >>>> >>