Re: [Qemu-devel] [PATCH 08/20] gluster: correctly propagate errors

[Paolo Bonzini <pbonzini@redhat.com>]

Il 10/02/2014 09:02, Fam Zheng ha scritto:
> On Sun, 02/09 10:48, Paolo Bonzini wrote:
>> > Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
>> > ---
>> >  block/gluster.c | 24 +++++++++++++-----------
>> >  1 file changed, 13 insertions(+), 11 deletions(-)
>> >
>> > diff --git a/block/gluster.c b/block/gluster.c
>> > index f9dd37f..bc9c59f 100644
>> > --- a/block/gluster.c
>> > +++ b/block/gluster.c
>> > @@ -175,7 +175,8 @@ out:
>> >      return ret;
>> >  }
>> >
>> > -static struct glfs *qemu_gluster_init(GlusterConf *gconf, const char *filename)
>> > +static struct glfs *qemu_gluster_init(GlusterConf *gconf, const char *filename,
>> > +                                      Error **errp)
>> >  {
>> >      struct glfs *glfs = NULL;
>> >      int ret;
>> > @@ -183,8 +184,8 @@ static struct glfs *qemu_gluster_init(GlusterConf *gconf, const char *filename)
>> >
>> >      ret = qemu_gluster_parseuri(gconf, filename);
>> >      if (ret < 0) {
>> > -        error_report("Usage: file=gluster[+transport]://[server[:port]]/"
>> > -            "volname/image[?socket=...]");
>> > +        error_setg(errp, "Usage: file=gluster[+transport]://[server[:port]]/"
>> > +                   "volname/image[?socket=...]");
>> >          errno = -ret;
>> >          goto out;
>> >      }
>> > @@ -211,9 +212,11 @@ static struct glfs *qemu_gluster_init(GlusterConf *gconf, const char *filename)
>> >
>> >      ret = glfs_init(glfs);
>> >      if (ret) {
>> > -        error_report("Gluster connection failed for server=%s port=%d "
>> > -             "volume=%s image=%s transport=%s", gconf->server, gconf->port,
>> > -             gconf->volname, gconf->image, gconf->transport);
>> > +        error_setg_errno(errp, errno,
>> > +                         "Gluster connection failed for server=%s port=%d "
>> > +                         "volume=%s image=%s transport=%s", gconf->server,
>> > +                         gconf->port, gconf->volname, gconf->image,
>> > +                         gconf->transport);
>> >          goto out;
>> >      }
>> >      return glfs;
>> > @@ -283,15 +286,14 @@ static int qemu_gluster_open(BlockDriverState *bs,  QDict *options,
>> >      opts = qemu_opts_create(&runtime_opts, NULL, 0, &error_abort);
>> >      qemu_opts_absorb_qdict(opts, options, &local_err);
>> >      if (error_is_set(&local_err)) {
>> > -        qerror_report_err(local_err);
>> > -        error_free(local_err);
>> > +        error_propagate(errp, local_err);
>> >          ret = -EINVAL;
>> >          goto out;
>> >      }
>> >
>> >      filename = qemu_opt_get(opts, "filename");
>> >
>> > -    s->glfs = qemu_gluster_init(gconf, filename);
>> > +    s->glfs = qemu_gluster_init(gconf, filename, errp);
>> >      if (!s->glfs) {
>> >          ret = -errno;
>> >          goto out;
>> > @@ -389,9 +391,9 @@ static int qemu_gluster_create(const char *filename,
>> >      int64_t total_size = 0;
>> >      GlusterConf *gconf = g_malloc0(sizeof(GlusterConf));
>> >
>> > -    glfs = qemu_gluster_init(gconf, filename);
>> > +    glfs = qemu_gluster_init(gconf, filename, errp);
>> >      if (!glfs) {
>> > -        ret = -errno;
>> > +        ret = -EINVAL;
> Why dropping -errno here?

Because it is not applicable for the usage error messages.  Anyway 
nothing is lost because the errno is already embedded in the error if 
applicable.  If the Error* is set to non-NULL, the caller of 
drv->bdrv_open ignores the return value except to check that it is <0.

Paolo