Re: [Qemu-devel] [PATCH v4 4/6] qemu-io: Add 'write -f' to test FUA flag

[Eric Blake]

On 05/06/2016 10:05 AM, Max Reitz wrote:
> On 05.05.2016 05:42, Eric Blake wrote:
>> Make it easier to test block drivers with BDRV_REQ_FUA in
>> .supported_write_flags, by adding the '-f' flag to qemu-io to
>> conditionally pass the flag through to specific writes ('write',
>> 'write -z', 'writev', 'aio_write', 'aio_write -z'). You'll want
>> to use 'qemu-io -t none' to actually make -f useful (as
>> otherwise, the default writethrough mode automatically sets the
>> FUA bit on every write).
>>
>> Signed-off-by: Eric Blake <address@hidden>
>> ---
>>  qemu-io-cmds.c | 57 
>> +++++++++++++++++++++++++++++++++++++++++----------------
>>  1 file changed, 41 insertions(+), 16 deletions(-)
>>
>> diff --git a/qemu-io-cmds.c b/qemu-io-cmds.c
>> index 8bcf742..ba811fe 100644
>> --- a/qemu-io-cmds.c
>> +++ b/qemu-io-cmds.c
> 
> [...]
> 
>> @@ -1010,6 +1018,11 @@ static int write_f(BlockBackend *blk, int argc, char 
>> **argv)
>>          return 0;
>>      }
>>
>> +    if ((flags & BDRV_REQ_FUA) && (bflag + cflag)) {
> 
> || would do the same job as +, except it looks nicer.

Holdover from rebasing the s/int/bool/ change earlier in the series.
Will fix.

> 
> Although technically correct, I'm very hesitant to give an R-b for
> boolean arithmetics.

Well-defined by C doesn't mean well-understood :)  I'm also more
comfortable with boolean operators for boolean variables; and I even
know of a recent patch to GNU coreutils due to gcc 7 starting to warn
about constructs on bool that look fishy because of promotion-to-int
when using non-bool operators.

-- 
Eric Blake   eblake redhat com    +1-919-301-3266
Libvirt virtualization library http://libvirt.org

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