[libvirt] [PATCH] Log an error when we fail to set the COW attribute

[Ján Tomko]

On 07/17/2014 01:54 PM, John Ferlan wrote:
> 
> 
> On 07/17/2014 06:22 AM, Ján Tomko wrote:
>> Coverity complains about the return value of ioctl not being checked.
>>
>> Even though we carry on when this fails (just like qemu-img does),
>> we can log an error.
>> ---
>>  src/storage/storage_backend.c | 9 +++++++--
>>  1 file changed, 7 insertions(+), 2 deletions(-)
>>
>> diff --git a/src/storage/storage_backend.c b/src/storage/storage_backend.c
>> index 5e7aa3c..b8b89ca 100644
>> --- a/src/storage/storage_backend.c
>> +++ b/src/storage/storage_backend.c
>> @@ -464,9 +464,14 @@ virStorageBackendCreateRaw(virConnectPtr conn ATTRIBUTE_UNUSED,
>>           * The FS_IOC_SETFLAGS ioctl return value will be ignored since any
>>           * failure of this operation should not block the left work.
>>           */
>> -        if (ioctl(fd, FS_IOC_GETFLAGS, &attr) == 0) {
>> +        if (ioctl(fd, FS_IOC_GETFLAGS, &attr) < 0) {
>> +            virReportSystemError(errno, "%s", _("Failed to get fs flags"));
>> +        } else {
>>              attr |= FS_NOCOW_FL;
>> -            ioctl(fd, FS_IOC_SETFLAGS, &attr);
>> +            if (ioctl(fd, FS_IOC_SETFLAGS, &attr) < 0) {
>> +                virReportSystemError(errno, "%s",
>> +                                     _("Failed to set NOCOW flag"));
>> +            }
>>          }
>>  #endif
>>      }
>>
> 
> Looks like you were already looking at the failure when my Coverity scan
> ran... Should have checked if there already was a patch before sending
> my response in Chunyan Liu's original series.
> 
> In any case, seems better to me to at least log the error whether or not
> the code wants to "block the left work" (any chance to clean that
> comment up a bit :-) - hopefully there's not too much "right work" left
> either).
> 
> ACK,
> 

I've changed "left work" to "volume creation" and pushed the patch.

Jan

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