Re: [PATCH] nbd: Fix regression with multiple meta contexts

[Eric Blake <eblake@redhat.com>]

On 2/12/20 3:24 AM, Laurent Vivier wrote:
> Le 06/02/2020 à 18:38, Eric Blake a écrit :
>> Detected by a hang in the libnbd testsuite.  If a client requests
>> multiple meta contexts (both base:allocation and qemu:dirty-bitmap:x)
>> at the same time, our attempt to silence a false-positive warning
>> about a potential uninitialized variable introduced botched logic: we
>> were short-circuiting the second context, and never sending the
>> NBD_REPLY_FLAG_DONE.  Combining two 'if' into one 'if/else' in
>> bdf200a55 was wrong (I'm a bit embarrassed that such a change was my
>> initial suggestion after the v1 patch, then I did not review the v2
>> patch that actually got committed). Revert that, and instead silence
>> the false positive warning by replacing 'return ret' with 'return 0'
>> (the value it always has at that point in the code, even though it
>> eluded the deduction abilities of the robot that reported the false
>> positive).
>>
>> Fixes: bdf200a5535
>> Signed-off-by: Eric Blake <eblake@redhat.com>
>> ---
>>
>> It's never fun when a regression is caused by a patch taken through
>> qemu-trivial, proving that the patch was not trivial after all.
> 
> Do you want this one be merged using the trivial branch?

Up to you; I'm also fine taking it through my NBD tree as I have a few 
other NBD patches landing soon.

-- 
Eric Blake, Principal Software Engineer
Red Hat, Inc.           +1-919-301-3226
Virtualization:  qemu.org | libvirt.org