blockdev: Make orphaned -drive fatal

Block backends defined with "-drive if=T" with T other than "none" are
meant to be picked up by machine initialization code: a suitable
frontend gets created and wired up automatically.

If machine initialization code doesn't comply, the block backend
remains unused.  This triggers a warning since commit a66c9dc7, v2.2.0.
Drives created by default are exempted; use -nodefaults to get rid of
them.

Turn this warning into an error.
Signed-off-by: NMarkus Armbruster <armbru@redhat.com>
Message-Id: <1487153147-11530-8-git-send-email-armbru@redhat.com>
Reviewed-by: NJohn Snow <jsnow@redhat.com>

blockdev.c

@@ -227,30 +227,30 @@ DriveInfo *drive_get(BlockInterfaceType type, int bus, int unit)
     return NULL;
 }
 
-bool drive_check_orphaned(void)
+void drive_check_orphaned(void)
 {
     BlockBackend *blk;
     DriveInfo *dinfo;
     Location loc;
-    bool rs = false;
+    bool orphans = false;
 
     for (blk = blk_next(NULL); blk; blk = blk_next(blk)) {
         dinfo = blk_legacy_dinfo(blk);
-        /* If dinfo->bdrv->dev is NULL, it has no device attached. */
-        /* Unless this is a default drive, this may be an oversight. */
         if (!blk_get_attached_dev(blk) && !dinfo->is_default &&
             dinfo->type != IF_NONE) {
             loc_push_none(&loc);
             qemu_opts_loc_restore(dinfo->opts);
-            error_report("warning: machine type does not support"
+            error_report("machine type does not support"
                          " if=%s,bus=%d,unit=%d",
                          if_name[dinfo->type], dinfo->bus, dinfo->unit);
             loc_pop(&loc);
-            rs = true;
+            orphans = true;
         }
     }
 
-    return rs;
+    if (orphans) {
+        exit(1);
+    }
 }
 
 DriveInfo *drive_get_by_index(BlockInterfaceType type, int index)

include/sysemu/blockdev.h

@@ -48,7 +48,7 @@ BlockBackend *blk_by_legacy_dinfo(DriveInfo *dinfo);
 void override_max_devs(BlockInterfaceType type, int max_devs);
 
 DriveInfo *drive_get(BlockInterfaceType type, int bus, int unit);
-bool drive_check_orphaned(void);
+void drive_check_orphaned(void);
 DriveInfo *drive_get_by_index(BlockInterfaceType type, int index);
 int drive_get_max_bus(BlockInterfaceType type);
 int drive_get_max_devs(BlockInterfaceType type);