Re: [Qemu-devel] [PATCH v2 3/3] block/nfs: switch to error_init_local

["Michael S. Tsirkin" <mst@redhat.com>]

On Wed, Jun 17, 2015 at 09:32:09AM -0600, Eric Blake wrote:
> On 06/17/2015 01:24 AM, Michael S. Tsirkin wrote:
> > We probably should just switch everyone, this is
> > just to demonstrate the API usage.
> > 
> > Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
> > ---
> >  block/nfs.c | 2 +-
> >  1 file changed, 1 insertion(+), 1 deletion(-)
> > 
> > diff --git a/block/nfs.c b/block/nfs.c
> > index ca9e24e..de4b8c3 100644
> > --- a/block/nfs.c
> > +++ b/block/nfs.c
> > @@ -385,7 +385,7 @@ static int nfs_file_open(BlockDriverState *bs, QDict *options, int flags,
> >      NFSClient *client = bs->opaque;
> >      int64_t ret;
> >      QemuOpts *opts;
> > -    Error *local_err = NULL;
> > +    Error *local_err = error_init_local(errp);
> >  
> >      client->aio_context = bdrv_get_aio_context(bs);
> 
> More context:
> 
> >     opts = qemu_opts_create(&runtime_opts, NULL, 0, &error_abort);
> >     qemu_opts_absorb_qdict(opts, options, &local_err);
> >     if (local_err) {
> >         error_propagate(errp, local_err);
> >         ret = -EINVAL;
> 
> Oops.  Your initialization means that if the caller passed in
> &error_abort, then local_err is now non-NULL, and we will attempt to do
> error_propagate(errp, error_abort), which will abort().  You'd have to
> change that to
>    if (!error_is_abort(local_err)) {

Looking at the alternatives, this seems like a reasonable change,
does it not?
Except it's a slightly ugly name, we need a new wrapper
     if (!error_is_set(local_err))
which does if (!local_err || local_err == &error_abort)
internally.

> -- 
> Eric Blake   eblake redhat com    +1-919-301-3266
> Libvirt virtualization library http://libvirt.org
>