From 6ad9fa64944b23817e8fa642c81fc3ecc93a3464 Mon Sep 17 00:00:00 2001
From: Olaf Hering <olaf@aepfle.de>
Date: Mon, 3 Sep 2012 19:50:44 +0200
Subject: force virtio_blk in old guest kernel

Signed-off-by: Olaf Hering <olaf@aepfle.de>
---
 fish/options.c         |  7 +++++--
 src/guestfs-internal.h |  1 +
 src/handle.c           | 16 ++++++++++++++++
 src/inspect-fs-unix.c  |  4 ++--
 src/launch-direct.c    |  2 ++
 test-tool/test-tool.c  | 15 ++++++++++++---
 6 files changed, 38 insertions(+), 7 deletions(-)

diff --git a/fish/options.c b/fish/options.c
index 770576b..6f143e1 100644
--- a/fish/options.c
+++ b/fish/options.c
@@ -100,7 +100,10 @@ add_drives (struct drv *drv, char next_drive)
 {
   int r;
   struct guestfs_add_drive_opts_argv ad_optargs;
-
+  int use_virtio_blk = 0;
+#ifdef GUESTFS_QEMU_NO_VIRTIO_BLK
+  use_virtio_blk = 1;
+#endif
   if (next_drive > 'z') {
     fprintf (stderr,
              _("%s: too many drives added on the command line\n"),
@@ -114,7 +117,7 @@ add_drives (struct drv *drv, char next_drive)
     free (drv->device);
     drv->device = NULL;
 
-    if (asprintf (&drv->device, "/dev/sd%c", next_drive) == -1) {
+    if (asprintf (&drv->device, "/dev/%s%c", use_virtio_blk ? "vd" : "sd", next_drive) == -1) {
       perror ("asprintf");
       exit (EXIT_FAILURE);
     }
diff --git a/src/guestfs-internal.h b/src/guestfs-internal.h
index 8888603..d4f6e90 100644
--- a/src/guestfs-internal.h
+++ b/src/guestfs-internal.h
@@ -472,6 +472,7 @@ struct guestfs_h
   unsigned int nr_requested_credentials;
   virConnectCredentialPtr requested_credentials;
 #endif
+  int use_virtio_blk;
 };
 
 /* Per-filesystem data stored for inspect_os. */
diff --git a/src/handle.c b/src/handle.c
index fffe825..4633df6 100644
--- a/src/handle.c
+++ b/src/handle.c
@@ -237,6 +237,22 @@ parse_environment (guestfs_h *g,
     }
   }
 
+/*
+ * Currently virtio_scsi is forced if qemu in the host supports this
+ * feature. This test does however not take the capabilities of the started
+ * guest into account. As a result no disks will be found if the guest
+ * kernel is older than 3.4.
+ */
+#ifdef GUESTFS_QEMU_NO_VIRTIO_BLK
+  static const char env_string[] = "GUESTFS_QEMU_NO_VIRTIO_BLK";
+  str = getenv(env_string);
+  g->use_virtio_blk = str == NULL;
+  if (str)
+    debug (g, "SuSE: %s in environment, preserving virtio-scsi setting.", env_string);
+  else
+    debug (g, "SuSE: %s not in environment, preventing virtio-scsi usage in old guest kernel.", env_string);
+#endif
+
   return 0;
 }
 
diff --git a/src/inspect-fs-unix.c b/src/inspect-fs-unix.c
index 93e035f..6d38bf8 100644
--- a/src/inspect-fs-unix.c
+++ b/src/inspect-fs-unix.c
@@ -1419,7 +1419,7 @@ resolve_fstab_device_diskbyid (guestfs_h *g, const char *part,
     return 0;
 
   /* Make the partition name and check it exists. */
-  device = safe_asprintf (g, "/dev/sda%s", part);
+  device = safe_asprintf (g, "/dev/%sa%s", g->use_virtio_blk ? "vd" : "sd", part);
   if (!is_partition (g, device)) {
     free (device);
     return 0;
@@ -1512,7 +1512,7 @@ resolve_fstab_device (guestfs_h *g, const char *spec, Hash_table *md_map)
     if (disk_i != -1 && disk_i <= 26 &&
         slice_i > 0 && slice_i <= 1 /* > 4 .. see comment above */ &&
         part_i >= 0 && part_i < 26) {
-      device = safe_asprintf (g, "/dev/sd%c%d", disk_i + 'a', part_i + 5);
+      device = safe_asprintf (g, "/dev/%s%c%d", g->use_virtio_blk ? "vd" : "sd", disk_i + 'a', part_i + 5);
     }
   }
   else if ((part = match1 (g, spec, re_diskbyid)) != NULL) {
diff --git a/src/launch-direct.c b/src/launch-direct.c
index f44cc20..d212b87 100644
--- a/src/launch-direct.c
+++ b/src/launch-direct.c
@@ -1066,6 +1066,8 @@ qemu_supports_virtio_scsi (guestfs_h *g, struct backend_direct_data *data)
         data->virtio_scsi = 3;
     }
   }
+ if (g->use_virtio_blk)
+     data->virtio_scsi = 2;
 
   return data->virtio_scsi == 1;
 }
diff --git a/test-tool/test-tool.c b/test-tool/test-tool.c
index 3a35226..03565ac 100644
--- a/test-tool/test-tool.c
+++ b/test-tool/test-tool.c
@@ -44,6 +44,14 @@
 
 #define DEFAULT_TIMEOUT 600
 
+#ifdef GUESTFS_QEMU_NO_VIRTIO_BLK
+static const char disk[] = "/dev/vda";
+static const char part[] = "/dev/vda1";
+#else
+static const char disk[] = "/dev/sda";
+static const char part[] = "/dev/sda1";
+#endif
+
 static int timeout = DEFAULT_TIMEOUT;
 
 static void set_qemu (guestfs_h *g, const char *path, int use_wrapper);
@@ -186,6 +194,7 @@ main (int argc, char *argv[])
     exit (EXIT_FAILURE);
   }
   guestfs_set_verbose (g, 1);
+  guestfs_set_trace (g, 1);
 
   if (qemu)
     set_qemu (g, qemu, qemu_use_wrapper);
@@ -272,19 +281,19 @@ main (int argc, char *argv[])
   fflush (stdout);
 
   /* Create the filesystem and mount everything. */
-  if (guestfs_part_disk (g, "/dev/sda", "mbr") == -1) {
+  if (guestfs_part_disk (g, disk, "mbr") == -1) {
     fprintf (stderr,
              _("libguestfs-test-tool: failed to run part-disk\n"));
     exit (EXIT_FAILURE);
   }
 
-  if (guestfs_mkfs (g, "ext2", "/dev/sda1") == -1) {
+  if (guestfs_mkfs (g, "ext2", part) == -1) {
     fprintf (stderr,
              _("libguestfs-test-tool: failed to mkfs.ext2\n"));
     exit (EXIT_FAILURE);
   }
 
-  if (guestfs_mount (g, "/dev/sda1", "/") == -1) {
+  if (guestfs_mount (g, part, "/") == -1) {
     fprintf (stderr,
              _("libguestfs-test-tool: failed to mount /dev/sda1 on /\n"));
     exit (EXIT_FAILURE);