supermin_init.diff

--- o/supermin-5.1.15/init/init.c	2016-02-17 18:11:24.000000000 +0200
+++ supermin-5.1.15/init/init.c	2016-03-13 15:18:36.430069676 +0200
@@ -149,6 +149,7 @@
    */
   char *root, *path;
   size_t len;
+  int is_9p = !!strstr(cmdline, "rootfstype=9p");
   root = strstr (cmdline, "root=");
   if (root) {
     root += 5;
@@ -157,14 +158,28 @@
     len = strcspn (root, " ");
     root[len] = '\0';
 
+    if (is_9p) {
+        if (verbose)
+            fprintf (stderr, "supermin: mounting new 9p root %son /root\n", root);
+        if (mount (root, "/root", "9p", MS_NOATIME, "trans=virtio,version=9p2000.L,cache=loose")) {
+            perror ("mount /root");
+            exit (EXIT_FAILURE);
+        }
+        if (verbose)
+            fprintf (stderr, "supermin: mounted new 9p root %son /root\n", root);
+        goto mounted;
+    }
+
     asprintf (&path, "/sys/block/%s/dev", root);
 
     uint64_t delay_ns = 250000;
     int virtio_message = 0;
     while (delay_ns <= MAX_ROOT_WAIT * UINT64_C(1000000000)) {
       fp = fopen (path, "r");
-      if (fp != NULL)
+      if (fp != NULL) {
+        root = NULL;
         goto found;
+      }
 
       if (delay_ns > 1000000000) {
 	fprintf (stderr,
@@ -203,7 +218,7 @@
   }
 
   fprintf (stderr,
-           "supermin: no ext2 root device found\n"
+           "supermin: no ext2 or 9p root device found\n"
            "Please include FULL verbose output in your bug report.\n");
   exit (EXIT_FAILURE);
 
@@ -217,17 +232,6 @@
   int minor = atoi (p);
 
   fclose (fp);
-  if (umount ("/sys") == -1) {
-    perror ("umount: /sys");
-    exit (EXIT_FAILURE);
-  }
-
-  /* Make current process the controlling process of the tty. */
-  setsid ();
-#ifdef TIOCSCTTY
-  if (ioctl (0, TIOCSCTTY, 1) == -1)
-    perror ("ioctl: TIOCSCTTY");
-#endif
 
   if (verbose)
     fprintf (stderr, "supermin: creating /dev/root as block special %d:%d\n",
@@ -246,6 +250,18 @@
     exit (EXIT_FAILURE);
   }
 
+mounted:
+  if (umount ("/sys") == -1) {
+    perror ("umount: /sys");
+    exit (EXIT_FAILURE);
+  }
+  /* Make current process the controlling process of the tty. */
+  setsid ();
+#ifdef TIOCSCTTY
+  if (ioctl (0, TIOCSCTTY, 1) == -1)
+    perror ("ioctl: TIOCSCTTY");
+#endif
+
   /* Note that pivot_root won't work.  See the note in
    * Documentation/filesystems/ramfs-rootfs-initramfs.txt
    * We could remove the old initramfs files, but let's not bother.