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>
diff --git a/block.c b/block.c
index 31ca4c5..4c65035 100644
--- a/block.c
+++ b/block.c
@@ -665,6 +665,8 @@
void bdrv_delete(BlockDriverState *bs)
{
+ assert(!bs->peer);
+
/* remove from list, if necessary */
if (bs->device_name[0] != '\0') {
QTAILQ_REMOVE(&bdrv_states, bs, list);
@@ -678,6 +680,26 @@
qemu_free(bs);
}
+int bdrv_attach(BlockDriverState *bs, DeviceState *qdev)
+{
+ if (bs->peer) {
+ return -EBUSY;
+ }
+ bs->peer = qdev;
+ return 0;
+}
+
+void bdrv_detach(BlockDriverState *bs, DeviceState *qdev)
+{
+ assert(bs->peer == qdev);
+ bs->peer = NULL;
+}
+
+DeviceState *bdrv_get_attached(BlockDriverState *bs)
+{
+ return bs->peer;
+}
+
/*
* Run consistency checks on an image
*
