Chao Yu <c...@kernel.org> 于2024年11月6日周三 10:16写道： > > On 2024/11/5 19:02, Zhiguo Niu wrote: > > Chao Yu <c...@kernel.org> 于2024年11月5日周二 18:39写道： > >> > >> On 2024/11/5 15:28, Zhiguo Niu wrote: > >>> Chao Yu <c...@kernel.org> 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 <zhiguo....@unisoc.com> > >>>>> --- > >>>>> 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?" 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, > >>>> > >> >
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