block: Reuse reference handling from bdrv_open()

Remove the reference parameter and the related handling code from
bdrv_file_open(), since it exists in bdrv_open() now as well.
Signed-off-by: NMax Reitz <mreitz@redhat.com>
Reviewed-by: NBenoit Canet <benoit@irqsave.net>
Reviewed-by: NKevin Wolf <kwolf@redhat.com>
Signed-off-by: NKevin Wolf <kwolf@redhat.com>

block.c

@@ -961,8 +961,7 @@ free_and_fail:
  * dictionary, it needs to use QINCREF() before calling bdrv_file_open.
  */
 static int bdrv_file_open(BlockDriverState **pbs, const char *filename,
-                          const char *reference, QDict *options, int flags,
-                          Error **errp)
+                          QDict *options, int flags, Error **errp)
 {
     BlockDriverState *bs = NULL;
     BlockDriver *drv;
@@ -976,23 +975,6 @@ static int bdrv_file_open(BlockDriverState **pbs, const char *filename,
         options = qdict_new();
     }
 
-    if (reference) {
-        if (filename || qdict_size(options)) {
-            error_setg(errp, "Cannot reference an existing block device with "
-                       "additional options or a new filename");
-            return -EINVAL;
-        }
-        QDECREF(options);
-
-        bs = bdrv_lookup_bs(reference, reference, errp);
-        if (!bs) {
-            return -ENODEV;
-        }
-        bdrv_ref(bs);
-        *pbs = bs;
-        return 0;
-    }
-
     bs = bdrv_new("");
     bs->options = options;
     options = qdict_clone_shallow(options);
@@ -1245,12 +1227,6 @@ int bdrv_open(BlockDriverState **pbs, const char *filename,
 
     assert(pbs);
 
-    if (flags & BDRV_O_PROTOCOL) {
-        assert(!drv);
-        return bdrv_file_open(pbs, filename, reference, options,
-                              flags & ~BDRV_O_PROTOCOL, errp);
-    }
-
     if (reference) {
         bool options_non_empty = options ? qdict_size(options) : false;
         QDECREF(options);
@@ -1276,6 +1252,12 @@ int bdrv_open(BlockDriverState **pbs, const char *filename,
         return 0;
     }
 
+    if (flags & BDRV_O_PROTOCOL) {
+        assert(!drv);
+        return bdrv_file_open(pbs, filename, options, flags & ~BDRV_O_PROTOCOL,
+                              errp);
+    }
+
     if (*pbs) {
         bs = *pbs;
     } else {