[libvirt] [PATCH 1/2] storage: Fix coverity warning

[John Ferlan]

On 08/20/2013 05:08 AM, Osier Yang wrote:
> Introduced by commit e0139e30444:
> 
> 1777 	    /* Updating pool metadata */
> 
> (40) Event var_deref_op: Dereferencing null pointer "newvol".
>      Also see events: [assign_zero]
> 
> 1778 	    pool->def->allocation += newvol->allocation;
> 1779 	    pool->def->available -= newvol->allocation;
> ---
>  src/storage/storage_driver.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/src/storage/storage_driver.c b/src/storage/storage_driver.c
> index 7908ba6..63a954b 100644
> --- a/src/storage/storage_driver.c
> +++ b/src/storage/storage_driver.c
> @@ -1758,7 +1758,6 @@ storageVolCreateXMLFrom(virStoragePoolPtr obj,
>  
>      origvol->building = 0;
>      newvol->building = 0;
> -    newvol = NULL;
>      pool->asyncjobs--;
>  
>      if (origpool) {

...
The next condition is:

    if (buildret < 0) {
        virStoragePoolObjUnlock(pool);
        storageVolDelete(volobj, 0);
        pool = NULL;
        goto cleanup;
    }

Since previously we'd have 'newvol = NULL;' already, there would need to
be one added here too..  Since, prior to this there's code:

    pool->volumes.objs[pool->volumes.count++] = newvol;

which saves the pointer...

Perhaps it'd work better to do the following:

unsigned long long allocation = 0x0ULL;

...


allocation = newvol->allocation;
newvol = NULL;

...

pool->def->allocation += allocation;
pool->def->available -= allocation;



> @@ -1781,6 +1780,7 @@ storageVolCreateXMLFrom(virStoragePoolPtr obj,
>      VIR_INFO("Creating volume '%s' in storage pool '%s'",
>               volobj->name, pool->def->name);
>      ret = volobj;
> +    newvol = NULL;

and this would become unnecessary

>      volobj = NULL;
>  
>  cleanup:
>