Re: [PATCH] iotests: don't run tests requiring cached writes in '-nocache' mode

[Kevin Wolf]

Am 26.01.2024 um 12:04 hat Andrey Drobyshev geschrieben:
> On 1/26/24 12:24, Kevin Wolf wrote:
> > Am 11.12.2023 um 14:32 hat Andrey Drobyshev geschrieben:
> >> There're tests whose logic implies running without O_DIRECT set,
> >> otherwise they fail when running iotests in '-nocache' mode.  For these
> >> tests let's add _require_no_o_direct() helper which can be put in the
> >> preabmle and which makes sure '-nocache' isn't set.  Use it to skip
> >> running the following tests:
> >>
> >>   * 271: creates files with unaligned sizes, thus producing multiple
> >>     errors like:
> >>
> >> qemu-io: can't open device /path/to/t.qcow2.raw: Cannot get 'write'
> >> permission without 'resize': Image size is not a multiple of request 
> >> alignment
> >>
> >>   * 308, file-io-error: use fuse exports.  Though fuse does have
> >>     'direct-io' mode (see https://docs.kernel.org/filesystems/fuse-io.html)
> >>     we aren't using it yet, thus getting errors like:
> >>
> >> qemu-io: can't open device /path/to/t.qcow2.fuse: Could not open
> >> '/path/to/t.qcow2.fuse': filesystem does not support O_DIRECT
> >>
> >> Signed-off-by: Andrey Drobyshev <andrey.drobyshev@virtuozzo.com>
> > 
> > How are you running qemu-iotests to make these tests fail? I tried to
> > reproduce, but they just pass for me:
> > 
> > $ tests/qemu-iotests/check -qcow2 -nocache 271 308 file-io-error
> > [...]
> > 271             pass       [11:20:50] [11:21:11]   21.1s  (last: 20.4s) 
> > 308             pass       [11:21:11] [11:21:14]   3.3s   (last: 3.3s)  
> > file-io-error   pass       [11:21:14] [11:21:14]   0.3s   (last: 0.3s)  
> > Passed all 3 iotests
> > 
> > $ tests/qemu-iotests/check -raw -nocache 271 308 file-io-error
> > 271             not run    [11:21:20] [11:21:21]   ...                  not 
> > suitable for this image format: raw
> > 308             pass       [11:21:21] [11:21:24]   3.8s   (last: 2.8s)  
> > file-io-error   pass       [11:21:24] [11:21:25]   0.3s   (last: 0.3s)  
> > Not run: 271
> > Passed all 2 iotests
> > 
> > Kevin
> > 
> 
> As for the test 271, I imagine this might be caused by different request
> alignment.  The failure occurs in block.c, bdrv_node_refresh_perm().  If
> I print the alignment out explicitly, I get:
> 
> qemu-io: can't open device /path/to/t.qcow2.raw: Cannot get 'write'
> permission without 'resize': Image size is not a multiple of request
> alignment: 4096

Oh, do you have a 4k sector size? I think for me O_DIRECT only enforces
512 byte alignment. I can later try again on a 4k sector size loopback
device or something.

If so, I think that's worth mentioning in the commit message.

> For the record, I'm running tests on ext4.

I don't expect that this makes the difference, but xfs for me.

> I'm not sure about the fuse tests though.  Could it also have smth to do
> with the underlying fs?

Probably the same request alignment thing then.

Kevin