block: Catch attempt to attach multiple devices to a blockdev

For instance, -device scsi-disk,drive=foo -device scsi-disk,drive=foo
happily creates two SCSI disks connected to the same block device.
It's all downhill from there.

Device usb-storage deliberately attaches twice to the same blockdev,
which fails with the fix in place.  Detach before the second attach
there.

Also catch attempt to delete while a guest device model is attached.

Signed-off-by: Markus Armbruster <armbru@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>

1 files changed, 2 insertions, 1 deletions

diff --git a/hw/qdev.h b/hw/qdev.h
index 7a01a8170e..cbc89f2c1e 100644
--- a/hw/qdev.h
+++ b/hw/qdev.h
@@ -275,7 +275,8 @@ void qdev_prop_set_string(DeviceState *dev, const char *name, char *value);
 void qdev_prop_set_chr(DeviceState *dev, const char *name, CharDriverState *value);
 void qdev_prop_set_netdev(DeviceState *dev, const char *name, VLANClientState *value);
 void qdev_prop_set_vlan(DeviceState *dev, const char *name, VLANState *value);
-void qdev_prop_set_drive(DeviceState *dev, const char *name, BlockDriverState *value);
+int qdev_prop_set_drive(DeviceState *dev, const char *name, BlockDriverState *value) QEMU_WARN_UNUSED_RESULT;
+void qdev_prop_set_drive_nofail(DeviceState *dev, const char *name, BlockDriverState *value);
 void qdev_prop_set_macaddr(DeviceState *dev, const char *name, uint8_t *value);
 /* FIXME: Remove opaque pointer properties.  */
 void qdev_prop_set_ptr(DeviceState *dev, const char *name, void *value);