Re: [Qemu-block] Is the use of bdrv_getlength() in qcow.c kosher?

[Eric Blake]

On 08/04/2017 10:32 AM, Eric Blake wrote:
> On 08/04/2017 07:45 AM, Markus Armbruster wrote:
>> Markus Armbruster <address@hidden> writes:
>>
>>> bdrv_getlength() can fail.  The uses in qcow.c don't check.  Is that
>>> safe?
>>
>> There's another one in qcow2_co_pwritev_compressed().
>>
>> Yet another one in dump_refcounts().

I haven't seen a patch for these yet, so I'll submit one shortly.

>>
>> While we're talking: the one in qcow2_measure() assigns to a variable of
>> type ssize_t.  Should be int64_t.
> 
> Oh indeed.  I wonder if my recently-added qemu-iotests 190 will catch
> that on a 32-bit machine?  If not, it should...

I can't trigger a failure, because the code in question is doing:


        int64_t ssize = bdrv_getlength(in_bs);
        if (ssize < 0) {
            error_setg_errno(&local_err, -ssize,
                             "Unable to get image virtual_size");
            goto err;
        }

Yes, the variable name is odd, but the types look correct.

-- 
Eric Blake, Principal Software Engineer
Red Hat, Inc.           +1-919-301-3266
Virtualization:  qemu.org | libvirt.org

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