Re: [PATCH] generic: make 17[1-4] work well when btrfs compression is enabled

["Darrick J. Wong" <darrick.wong@oracle.com>]

On Mon, Oct 10, 2016 at 11:49:03AM +0800, Wang Xiaoguang wrote:
> hi,
> 
> On 10/10/2016 05:04 AM, Darrick J. Wong wrote:
> >On Sat, Oct 08, 2016 at 01:36:10AM +1100, Dave Chinner wrote:
> >>On Fri, Oct 07, 2016 at 03:00:42PM +0800, Wang Xiaoguang wrote:
> >>>When enabling btrfs compression, original codes can not fill fs
> >>>correctly, fix this.
> >>>
> >>>Signed-off-by: Wang Xiaoguang <wangxg.fnst@cn.fujitsu.com>
> >>>---
> >>>  tests/generic/171 | 4 +---
> >>>  tests/generic/172 | 2 +-
> >>>  tests/generic/173 | 4 +---
> >>>  tests/generic/174 | 4 +---
> >>>  4 files changed, 4 insertions(+), 10 deletions(-)
> >>>
> >>>diff --git a/tests/generic/171 b/tests/generic/171
> >>>index f391685..d2ae8e4 100755
> >>>--- a/tests/generic/171
> >>>+++ b/tests/generic/171
> >>>@@ -75,9 +75,7 @@ _cp_reflink $testdir/bigfile $testdir/clonefile
> >>>  sync
> >>>  echo "Allocate the rest of the space"
> >>>-nr_free=$(stat -f -c '%f' $testdir)
> >>>-touch $testdir/file0 $testdir/file1
> >Why remove this line which ensures that the inode we're going to use (file1)
> >later in the test has been allocated /before/ we try to eat all the space?
> Sorry, I don't understand :)
> In generic/171, generic/172, generic/173, generic/174, you created file0 and
> file1, but I don't see test cases use them and they are empty.
> 
> >
> >>>-_pwrite_byte 0x61 0 $((blksz * nr_free)) $testdir/eat_my_space >> $seqres.full 2>&1
> >>>+dd if=/dev/zero of=$testdir/eat_my_space >> $seqres.full 2>&1
> >Uh... isn't a bunch of zeroes just as compressible as 0x61?
> 0x61 is also compressible.
> >I suppose
> >the point here is to write until write returns ENOSPC, since in btrfs
> >land we can't assume that writing $nr blocks will use up at least that
> >much space.
> Yes.

Ok, just making sure I figured it out correctly. :)

> >
> >Does XFS reflink still pass this test with this patch?
> Could you please give a stable xfs repotory that supports xfs reflink,
> thanks.

The for-next branch of Dave Chinner's kernel tree:
https://git.kernel.org/cgit/linux/kernel/git/dgc/linux-xfs.git/?h=for-next

And userspace programs in my repo:
https://github.com/djwong/xfsprogs/tree/for-dave-for-4.9-10

(I wouldn't call them stable, but they are what's submitted for 4.9.)

> >>Please don't replace xfs_io writes using a specific data pattern
> >>with dd calls that write zeros. Indeed, we don't use dd for new
> >>tests anymore - xfs_io should be used.
> >>
> >>Write a function that fills all the remaining free space (one may
> >>already exist) and call it in all these places.
> >Yeah, there already are a few of these...
> OK, I'll use it, thanks.

No problem! :)

--D

> 
> Regards,
> Xiaoguang Wang
> >
> >--D
> >
> >>Cheers,
> >>
> >>Dave.
> >>-- 
> >>Dave Chinner
> >>david@fromorbit.com
> >>--
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> >
> 
> 
>