linux-ext4 - Re: [PATCH] generic/473: fix expectation properly in out file

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Date:   Wed, 24 Feb 2021 17:16:26 +0800
From:   Chengguang Xu <cgxu519@...ernel.net>
To:     "Su Yue" <l@...enly.su>
Cc:     "guaneryu" <guaneryu@...il.com>,
        "fstests" <fstests@...r.kernel.org>,
        "linux-fsdevel" <linux-fsdevel@...r.kernel.org>,
        "linux-ext4" <linux-ext4@...r.kernel.org>,
        "linux-xfs" <linux-xfs@...r.kernel.org>,
        "linux-btrfs" <linux-btrfs@...r.kernel.org>
Subject: Re: [PATCH] generic/473: fix expectation properly in out file

 ---- 在 星期三, 2021-02-24 16:51:03 Chengguang Xu <cgxu519@...ernel.net> 撰写 ----
 >  ---- 在 星期三, 2021-02-24 15:52:17 Su Yue <l@...enly.su> 撰写 ----
 >  > 
 >  > Cc to the author and linux-xfs, since it's xfsprogs related.
 >  > 
 >  > On Tue 23 Feb 2021 at 21:40, Chengguang Xu <cgxu519@...ernel.net> 
 >  > wrote:
 >  > 
 >  > > It seems the expected result of testcase of "Hole + Data"
 >  > > in generic/473 is not correct, so just fix it properly.
 >  > >
 >  > 
 >  > But it's not proper...
 >  > 
 >  > > Signed-off-by: Chengguang Xu <cgxu519@...ernel.net>
 >  > > ---
 >  > >  tests/generic/473.out | 2 +-
 >  > >  1 file changed, 1 insertion(+), 1 deletion(-)
 >  > >
 >  > > diff --git a/tests/generic/473.out b/tests/generic/473.out
 >  > > index 75816388..f1ee5805 100644
 >  > > --- a/tests/generic/473.out
 >  > > +++ b/tests/generic/473.out
 >  > > @@ -6,7 +6,7 @@ Data + Hole
 >  > >  1: [256..287]: hole
 >  > >  Hole + Data
 >  > >  0: [0..127]: hole
 >  > > -1: [128..255]: data
 >  > > +1: [128..135]: data
 >  > >
 >  > The line is produced by `$XFS_IO_PROG -c "fiemap -v 0 65k" $file | 
 >  > _filter_fiemap`.
 >  > 0-64k is a hole and 64k-128k is a data extent.
 >  > fiemap ioctl always returns *complete* ranges of extents.

Finally, I found btrfs returns *complete* rangne of extents but xfs/ext4 does not. :-/


[root@...89-226-centos /test]# xfs_io -c "fiemap 0 65k" a
a:
        0: [0..127]: hole
        1: [128..255]: 24576..24703
[root@...89-226-centos /test]# xfs_io -c "fiemap 0 128k" a
a:
        0: [0..127]: hole
        1: [128..255]: 24576..24703



 > 
 > Manual testing result in latest kernel like below.
 > 
 > [root@...tos test]# uname -a
 > Linux centos 5.11.0+ #5 SMP Tue Feb 23 21:02:27 CST 2021 x86_64 x86_64 x86_64 GNU/Linux
 > 
 > [root@...tos test]# xfs_io -V
 > xfs_io version 5.0.0
 > 
 > [root@...tos test]# stat a
 >   File: a
 >   Size: 4194304         Blocks: 0          IO Block: 4096   regular file
 > Device: fc01h/64513d    Inode: 140         Links: 1
 > Access: (0644/-rw-r--r--)  Uid: (    0/    root)   Gid: (    0/    root)
 > Access: 2021-02-24 16:33:20.235654140 +0800
 > Modify: 2021-02-24 16:33:25.070641521 +0800
 > Change: 2021-02-24 16:33:25.070641521 +0800
 >  Birth: -
 >  
 > [root@...tos test]# xfs_io -c "pwrite 64k 64k" a
 > wrote 65536/65536 bytes at offset 65536
 > 64 KiB, 16 ops; 0.0000 sec (992.063 MiB/sec and 253968.2540 ops/sec)
 > 
 > [root@...8-4-centos test]# xfs_io -c "fiemap -v 0 65k" a
 > a:
 >  EXT: FILE-OFFSET      BLOCK-RANGE      TOTAL FLAGS
 >    0: [0..127]:        hole               128
 >    1: [128..135]:      360..367             8   0x1
 >    
 > [root@...tos test]# xfs_io -c "fiemap -v 0 128k" a
 > a:
 >  EXT: FILE-OFFSET      BLOCK-RANGE      TOTAL FLAGS
 >    0: [0..127]:        hole               128
 >    1: [128..255]:      360..487           128   0x1
 > 
 > 
 >  > 
 >  > You may ask why the ending hole range is not aligned to 128 in 
 >  > 473.out. Because
 >  > fiemap ioctl returns nothing of querying holes. xfs_io does the 
 >  > extra
 >  > print work for holes.
 >  > 
 >  > xfsprogs-dev/io/fiemap.c:
 >  > for holes:
 >  >  153     if (lstart > llast) {
 >  >  154         print_hole(0, 0, 0, cur_extent, lflag, true, llast, 
 >  >  lstart);
 >  >  155         cur_extent++;
 >  >  156         num_printed++;
 >  >  157     }
 >  > 
 >  > for the ending hole:
 >  >   381     if (cur_extent && last_logical < range_end)
 >  >   382         print_hole(foff_w, boff_w, tot_w, cur_extent, lflag, 
 >  >   !vflag,
 >  >   383                BTOBBT(last_logical), BTOBBT(range_end));
 >  > 
 >  > >  Hole + Data + Hole
 >  > >  0: [0..127]: hole
 >  > >  1: [128..255]: data
 >  > 
 >