[Spice-devel] [PATCH 07/12] block: save the associated child in BlockDriverState

[Marc-André Lureau]

Hi


On Fri, Jun 21, 2013 at 12:25 AM, Paolo Bonzini <pbonzini at redhat.com> wrote:

> Il 20/06/2013 19:46, Marc-André Lureau ha scritto:
> > This allows the Spice block driver to eject the associated device.
>
> The child can change when you have for example a streaming operation.
>

Ah, can you point me to some function or some way I can reproduce? I don't
know what you mean by a streaming operation here.

What exactly are you trying to do here (I guess I'll understand more
> when I get to the later patches)?
>

Getting to the bottom BlockDriverState to be able to eject & change it. (it
could also be named the "parent", but other parts of the code suggest the
"child" name)

>
> Can you draw the relationships between all the BlockDriverStates in a
> spicebd: drive?
>

Hopefully, but I have only tested with raw images (w/wo snapshot).


> Paolo
>
> > Signed-off-by: Marc-André Lureau <marcandre.lureau at redhat.com>
> > ---
> >  block.c                   | 46
> +++++++++++++++++++++++++++++-----------------
> >  include/block/block_int.h |  1 +
> >  2 files changed, 30 insertions(+), 17 deletions(-)
> >
> > diff --git a/block.c b/block.c
> > index b88ad2f..f502eed 100644
> > --- a/block.c
> > +++ b/block.c
> > @@ -294,7 +294,8 @@ void bdrv_register(BlockDriver *bdrv)
> >  }
> >
> >  /* create a new block device (by default it is empty) */
> > -BlockDriverState *bdrv_new(const char *device_name)
> > +static BlockDriverState *bdrv_new_int(const char *device_name,
> > +    BlockDriverState *child)
> >  {
> >      BlockDriverState *bs;
> >
> > @@ -305,10 +306,16 @@ BlockDriverState *bdrv_new(const char *device_name)
> >      }
> >      bdrv_iostatus_disable(bs);
> >      notifier_list_init(&bs->close_notifiers);
> > +    bs->child = child;
> >
> >      return bs;
> >  }
> >
> > +BlockDriverState *bdrv_new(const char *device_name)
> > +{
> > +    return bdrv_new_int(device_name, NULL);
> > +}
> > +
> >  void bdrv_add_close_notifier(BlockDriverState *bs, Notifier *notify)
> >  {
> >      notifier_list_add(&bs->close_notifiers, notify);
> > @@ -769,16 +776,8 @@ free_and_fail:
> >      return ret;
> >  }
> >
> > -/*
> > - * Opens a file using a protocol (file, host_device, nbd, ...)
> > - *
> > - * options is a QDict of options to pass to the block drivers, or NULL
> for an
> > - * empty set of options. The reference to the QDict belongs to the
> block layer
> > - * after the call (even on failure), so if the caller intends to reuse
> the
> > - * dictionary, it needs to use QINCREF() before calling bdrv_file_open.
> > - */
> > -int bdrv_file_open(BlockDriverState **pbs, const char *filename,
> > -                   QDict *options, int flags)
> > +static int bdrv_file_open_int(BlockDriverState **pbs, const char
> *filename,
> > +    QDict *options, int flags, BlockDriverState *child)
> >  {
> >      BlockDriverState *bs;
> >      BlockDriver *drv;
> > @@ -790,7 +789,7 @@ int bdrv_file_open(BlockDriverState **pbs, const
> char *filename,
> >          options = qdict_new();
> >      }
> >
> > -    bs = bdrv_new("");
> > +    bs = bdrv_new_int("", child);
> >      bs->options = options;
> >      options = qdict_clone_shallow(options);
> >
> > @@ -873,6 +872,20 @@ fail:
> >  }
> >
> >  /*
> > + * Opens a file using a protocol (file, host_device, nbd, ...)
> > + *
> > + * options is a QDict of options to pass to the block drivers, or NULL
> for an
> > + * empty set of options. The reference to the QDict belongs to the
> block layer
> > + * after the call (even on failure), so if the caller intends to reuse
> the
> > + * dictionary, it needs to use QINCREF() before calling bdrv_file_open.
> > + */
> > +int bdrv_file_open(BlockDriverState **pbs, const char *filename,
> > +                   QDict *options, int flags)
> > +{
> > +    return bdrv_file_open_int(pbs, filename, options, flags, NULL);
> > +}
> > +
> > +/*
> >   * Opens the backing file for a BlockDriverState if not yet open
> >   *
> >   * options is a QDict of options to pass to the block drivers, or NULL
> for an
> > @@ -904,7 +917,7 @@ int bdrv_open_backing_file(BlockDriverState *bs,
> QDict *options)
> >          return 0;
> >      }
> >
> > -    bs->backing_hd = bdrv_new("");
> > +    bs->backing_hd = bdrv_new_int("", bs);
> >      bdrv_get_full_backing_filename(bs, backing_filename,
> >                                     sizeof(backing_filename));
> >
> > @@ -990,7 +1003,7 @@ int bdrv_open(BlockDriverState *bs, const char
> *filename, QDict *options,
> >             instead of opening 'filename' directly */
> >
> >          /* if there is a backing file, use it */
> > -        bs1 = bdrv_new("");
> > +        bs1 = bdrv_new_int("", bs);
> >          ret = bdrv_open(bs1, filename, NULL, 0, drv);
> >          if (ret < 0) {
> >              bdrv_delete(bs1);
> > @@ -1043,9 +1056,8 @@ int bdrv_open(BlockDriverState *bs, const char
> *filename, QDict *options,
> >      }
> >
> >      extract_subqdict(options, &file_options, "file.");
> > -
> > -    ret = bdrv_file_open(&file, filename, file_options,
> > -                         bdrv_open_flags(bs, flags));
> > +    ret = bdrv_file_open_int(&file, filename, file_options,
> > +                             bdrv_open_flags(bs, flags), bs);
> >      if (ret < 0) {
> >          goto fail;
> >      }
> > diff --git a/include/block/block_int.h b/include/block/block_int.h
> > index ba52247..9c72b32 100644
> > --- a/include/block/block_int.h
> > +++ b/include/block/block_int.h
> > @@ -245,6 +245,7 @@ struct BlockDriverState {
> >
> >      BlockDriverState *backing_hd;
> >      BlockDriverState *file;
> > +    BlockDriverState *child;
> >
> >      NotifierList close_notifiers;
> >
> >
>
>


-- 
Marc-André Lureau
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