Re: [Qemu-devel] [PATCH V6 2/8] block: Allow the user to define "node-name" option both on command line and QMP.

[Kevin Wolf <kwolf@redhat.com>]

Am 24.01.2014 um 15:51 hat Benoît Canet geschrieben:
> Le Thursday 23 Jan 2014 à 21:31:33 (+0100), Benoît Canet a écrit :
> > From: Benoît Canet <benoit@irqsave.net>
> > 
> > Signed-off-by: Benoit Canet <benoit@irqsave.net>
> > ---
> >  block.c          | 36 ++++++++++++++++++++++++++++++++++++
> >  qapi-schema.json |  2 ++
> >  2 files changed, 38 insertions(+)
> > 
> > diff --git a/block.c b/block.c
> > index 60b70bc..d9d02d2 100644
> > --- a/block.c
> > +++ b/block.c
> > @@ -728,6 +728,33 @@ static int bdrv_open_flags(BlockDriverState *bs, int flags)
> >      return open_flags;
> >  }
> >  
> > +static int bdrv_assign_node_name(BlockDriverState *bs,
> > +                                 const char *node_name,
> > +                                 Error **errp)
> > +{
> > +    if (!node_name) {
> > +        return 0;
> > +    }
> > +
> > +    /* empty string node name is invalid */
> > +    if (node_name[0] == '\0') {
> > +        error_setg(errp, "Empty node name");
> > +        return -EINVAL;
> > +    }
> > +
> > +    /* takes care of avoiding duplicates node names */
> > +    if (bdrv_find_node(node_name)) {
> > +        error_setg(errp, "Duplicate node name");
> > +        return -EINVAL;
> > +    }
> > +
> > +    /* copy node name into the bs and insert it into the graph list */
> > +    pstrcpy(bs->node_name, sizeof(bs->node_name), node_name);
> > +    QTAILQ_INSERT_TAIL(&graph_bdrv_states, bs, node_list);
> > +
> > +    return 0;
> > +}
> > +
> >  /*
> >   * Common part for opening disk images and files
> >   *
> > @@ -738,6 +765,7 @@ static int bdrv_open_common(BlockDriverState *bs, BlockDriverState *file,
> >  {
> >      int ret, open_flags;
> >      const char *filename;
> > +    const char *node_name = NULL;
> >      Error *local_err = NULL;
> >  
> >      assert(drv != NULL);
> > @@ -752,6 +780,14 @@ static int bdrv_open_common(BlockDriverState *bs, BlockDriverState *file,
> >  
> >      trace_bdrv_open_common(bs, filename ?: "", flags, drv->format_name);
> >  
> > +    node_name = qdict_get_try_str(options, "node-name");
> 
> > +    qdict_del(options, "node-name");
> 
> Kevin: I wonder if I delete the option too early hence zeroing node-name ? 

For the record, we concluded on IRC that I would squash the following
patch in:

diff --git a/block.c b/block.c
index 9dc1216..f043669 100644
--- a/block.c
+++ b/block.c
@@ -788,12 +788,11 @@ static int bdrv_open_common(BlockDriverState *bs, BlockDriverState *file,
     trace_bdrv_open_common(bs, filename ?: "", flags, drv->format_name);
 
     node_name = qdict_get_try_str(options, "node-name");
-    qdict_del(options, "node-name");
-
     ret = bdrv_assign_node_name(bs, node_name, errp);
     if (ret < 0) {
         return ret;
     }
+    qdict_del(options, "node-name");
 
     /* bdrv_open() with directly using a protocol as drv. This layer is already
      * opened, so assign it to bs (while file becomes a closed BlockDriverState)

Kevin

> > +
> > +    ret = bdrv_assign_node_name(bs, node_name, errp);
> > +    if (ret < 0) {
> > +        return ret;
> > +    }
> > +
> >      /* bdrv_open() with directly using a protocol as drv. This layer is already
> >       * opened, so assign it to bs (while file becomes a closed BlockDriverState)
> >       * and return immediately. */
> > diff --git a/qapi-schema.json b/qapi-schema.json
> > index 35f7b34..04167da 100644
> > --- a/qapi-schema.json
> > +++ b/qapi-schema.json
> > @@ -4090,6 +4090,7 @@
> >  # @id:          #optional id by which the new block device can be referred to.
> >  #               This is a required option on the top level of blockdev-add, and
> >  #               currently not allowed on any other level.
> > +# @node-name:   #optional the name of a block driver state node (Since 2.0)
> >  # @discard:     #optional discard-related options (default: ignore)
> >  # @cache:       #optional cache-related options
> >  # @aio:         #optional AIO backend (default: threads)
> > @@ -4105,6 +4106,7 @@
> >  { 'type': 'BlockdevOptionsBase',
> >    'data': { 'driver': 'str',
> >              '*id': 'str',
> > +            '*node-name': 'str',
> >              '*discard': 'BlockdevDiscardOptions',
> >              '*cache': 'BlockdevCacheOptions',
> >              '*aio': 'BlockdevAioOptions',
> > -- 
> > 1.8.3.2
> >