Re: [Qemu-devel] [RFC 10/10] QMP/HMP: change: Use QMP tray commands

[Luiz Capitulino <lcapitulino@redhat.com>]

On Mon, 6 Jun 2011 17:18:31 +0530
Amit Shah <amit.shah@redhat.com> wrote:

> On (Fri) 03 Jun 2011 [16:04:02], Luiz Capitulino wrote:
> > This commit rewrites change in terms of blockdev-tray-open,
> > blockdev-media-insert and blockdev-tray-close.
> > 
> > There should be no visible changes in HMP or QMP, except that
> > the use of this command causes the BLOCK_TRAY_OPEN *and*
> > BLOCK_TRAY_CLOSE events to emitted.
> > 
> > Signed-off-by: Luiz Capitulino <lcapitulino@redhat.com>
> > ---
> >  blockdev.c |   43 +++++++++----------------------------------
> >  1 files changed, 9 insertions(+), 34 deletions(-)
> > 
> > diff --git a/blockdev.c b/blockdev.c
> > index 36c56fd..e9edcb3 100644
> > --- a/blockdev.c
> > +++ b/blockdev.c
> > @@ -648,23 +648,6 @@ out:
> >      return ret;
> >  }
> >  
> > -static int eject_device(Monitor *mon, BlockDriverState *bs, int force)
> > -{
> > -    if (!force) {
> > -        if (!bdrv_is_removable(bs)) {
> > -            qerror_report(QERR_DEVICE_NOT_REMOVABLE,
> > -                           bdrv_get_device_name(bs));
> > -            return -1;
> > -        }
> > -        if (bdrv_is_locked(bs)) {
> > -            qerror_report(QERR_DEVICE_LOCKED, bdrv_get_device_name(bs));
> > -            return -1;
> > -        }
> > -    }
> > -    bdrv_close(bs);
> > -    return 0;
> > -}
> > -
> >  static BlockDriverState *bdrv_removable_find(const char *name)
> >  {
> >      BlockDriverState *bs;
> > @@ -819,30 +802,22 @@ int do_change_block(Monitor *mon, const char *device,
> >                      const char *filename, const char *fmt)
> >  {
> >      BlockDriverState *bs;
> > -    BlockDriver *drv = NULL;
> > -    int bdrv_flags;
> >  
> > -    bs = bdrv_find(device);
> > -    if (!bs) {
> > -        qerror_report(QERR_DEVICE_NOT_FOUND, device);
> > +    if (tray_open(device, 1, 0) < 0) { /* XXX: should we force? */
> >          return -1;
> >      }
> > -    if (fmt) {
> > -        drv = bdrv_find_whitelisted_format(fmt);
> > -        if (!drv) {
> > -            qerror_report(QERR_INVALID_BLOCK_FORMAT, fmt);
> > -            return -1;
> > -        }
> > -    }
> > -    if (eject_device(mon, bs, 0) < 0) {
> > +
> > +    if (media_insert(device, filename, fmt) < 0) {
> >          return -1;
> >      }
> > -    bdrv_flags = bdrv_is_read_only(bs) ? 0 : BDRV_O_RDWR;
> > -    bdrv_flags |= bdrv_is_snapshot(bs) ? BDRV_O_SNAPSHOT : 0;
> > -    if (bdrv_open(bs, filename, bdrv_flags, drv) < 0) {
> > -        qerror_report(QERR_OPEN_FILE_FAILED, filename);
> > +
> > +    if (tray_close(device) < 0) {
> > +        /* XXX: open the tray and remove the media? */
> >          return -1;
> >      }
> 
> So if the new medium points to a non-existent file, close will fail,

media_insert() will and tray_close() won't be called. That's what you
meant, right?

> and leave the tray in the open state.  A next change command will fail
> because the tray is already open.  Not a good thing.

tray_open() shouldn't fail if the tray is already open.