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

[Andrey Drobyshev]

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

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

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

Andrey