[libvirt PATCH] storage_backend_fs: use MKFS ony if WITH_STORAGE_FS is defined

[Michal Privoznik]

On 4/21/21 4:23 PM, Pavel Hrdina wrote:
> On Wed, Apr 21, 2021 at 04:06:05PM +0200, Michal Privoznik wrote:
>> On 4/21/21 3:33 PM, Pavel Hrdina wrote:
>>> The code in storage_backend_fs is used for storage_dir and storage_fs
>>> drivers so some parts need to be guarded by checking for
>>> WITH_STORAGE_FS.
>>>
>>> Fixes: 16c69e7aaed4cabfd8e8c19cc326854d4c480437
>>> Signed-off-by: Pavel Hrdina <phrdina at redhat.com>
>>> ---
>>>
>>> GitLab CI faild on MacOS and FreeBSD where storage_fs is disabled.
>>>
>>>    src/storage/storage_backend_fs.c | 2 ++
>>>    1 file changed, 2 insertions(+)
>>>
>>> diff --git a/src/storage/storage_backend_fs.c b/src/storage/storage_backend_fs.c
>>> index af645ea9de..e6a348521d 100644
>>> --- a/src/storage/storage_backend_fs.c
>>> +++ b/src/storage/storage_backend_fs.c
>>> @@ -401,6 +401,7 @@ static int
>>>    virStorageBackendExecuteMKFS(const char *device,
>>>                                 const char *format)
>>>    {
>>> +#if WITH_STORAGE_FS
>>>        g_autoptr(virCommand) cmd = NULL;
>>>        g_autofree char *mkfs = virFindFileInPath(MKFS);
>>> @@ -431,6 +432,7 @@ virStorageBackendExecuteMKFS(const char *device,
>>>        if (virCommandRun(cmd, NULL) < 0)
>>>            return -1;
>>> +#endif /* WITH_STORAGE_FS */
>>>        return 0;
>>>    }
>>>
>>
>> This function has only one caller so we can be sure for now that it is not
>> called when !WITH_STORAGE_FS but I think we would be much more safe if in
>> that case an error would be returned, instead of return 0.
>>
>> Can't we do something like this?
>>
>> diff --git c/src/storage/storage_backend_fs.c
>> w/src/storage/storage_backend_fs.c
>> index af645ea9de..09da8ec8b6 100644
>> --- c/src/storage/storage_backend_fs.c
>> +++ w/src/storage/storage_backend_fs.c
>> @@ -402,7 +402,11 @@ virStorageBackendExecuteMKFS(const char *device,
>>                                const char *format)
>>   {
>>       g_autoptr(virCommand) cmd = NULL;
>> -    g_autofree char *mkfs = virFindFileInPath(MKFS);
>> +    g_autofree char *mkfs = NULL;
>> +
>> +#ifdef MKFS
>> +    mkfs = virFindFileInPath(MKFS);
>> +#endif
> 
> I wanted to avoid using #ifdef MKFS because once this series [1] is
> merged it will be always true. In addition using WITH_STORAGE_FS is what
> we do for other functions in this file as well so I wanted to keep it
> consistent.

But MKFS is not only used when WITH_STORAGE_FS. It's also used for 
VIR_STORAGE_POOL_DIR: There' a path from 
virStorageBackendFileSystemBuild() to virStorageBackendExecuteMKFS().

And your suggested patches are not merged yet, thus what I'm suggesting 
feels a bit more correct.

> 
> If you are OK with using WITH_STORAGE_FS instead of MKFS in the ifdef
> we can push this version.

But okay, I guess I can live with success reported incorrectly on 
freebsd and mac :-)

Michal