[Virtio-fs] [PATCH] init/do_mounts.c: add virtio_fs root fs support

[Stefan Hajnoczi]

It is useful to mount the root file system via virtio_fs.  During
testing a monolithic kernel is more convenient than an initramfs but
we'll need to teach the kernel how to boot directly from virtio_fs.

Signed-off-by: Stefan Hajnoczi <stefanha at redhat.com>
---
 init/do_mounts.c | 10 ++++++++++
 1 file changed, 10 insertions(+)

diff --git a/init/do_mounts.c b/init/do_mounts.c
index f8c230c77035..b2d9650488d7 100644
--- a/init/do_mounts.c
+++ b/init/do_mounts.c
@@ -553,6 +553,16 @@ void __init mount_root(void)
 			change_floppy("root floppy");
 	}
 #endif
+#ifdef CONFIG_VIRTIO_FS
+	if (root_fs_names && !strcmp(root_fs_names, "virtio_fs")) {
+		if (!do_mount_root(root_device_name, "virtio_fs",
+				   root_mountflags, root_mount_data))
+			return;
+
+		panic("VFS: Unable to mount root fs \"%s\" from virtio_fs",
+		      root_device_name);
+	}
+#endif
 #ifdef CONFIG_BLOCK
 	{
 		int err = create_dev("/dev/root", ROOT_DEV);
-- 
2.21.0