[PATCH] initramfs + sysfs as root fix

[PATCH] initramfs + sysfs as root fix

[Garrett Kajmowicz]

This is my first real patch, so please vet thoroughly

This patch allows a person to not require mounting a root device at startup.  
This works idealy for people trying to use the initramfs/sysfs as the only 
filesystem.

What happens is that when the root device is set to 0,0 mount_root is not 
called.  I have tested in VMWare extensively, and the patch is quite minimal.

Please let me know if I should send this somewhere else as well.

Also, please be adviased that I did not dream up the goto - I am just keeping 
in line with the existing file structure.


Garrett Kajmowicz
gkajmowi@tbaytel.net

--- linux-2.6.0-test3/init/do_mounts.c  2003-08-09 00:34:47.000000000 -0400
+++ linux/init/do_mounts.c      2003-08-23 17:22:59.000000000 -0400
@@ -380,6 +380,12 @@
        if (is_floppy && rd_doload && rd_load_disk(0))
                ROOT_DEV = Root_RAM0;

+#ifndef CONFIG_ROOT_NFS
+       if (MAJOR(ROOT_DEV) == UNNAMED_MAJOR && MINOR(ROOT_DEV) == 0) {
+               goto out;
+       }
+#endif
+
        mount_root();
 out:
        umount_devfs("/dev");

Re: [PATCH] initramfs + sysfs as root fix

[H. Peter Anvin]

Followup to:  <200308232157.53962.gkajmowi@tbaytel.net>
By author:    Garrett Kajmowicz <gkajmowi@tbaytel.net>
In newsgroup: linux.dev.kernel
>
> This is my first real patch, so please vet thoroughly
> 
> This patch allows a person to not require mounting a root device at startup.  
> This works idealy for people trying to use the initramfs/sysfs as the only 
> filesystem.
> 
> What happens is that when the root device is set to 0,0 mount_root is not 
> called.  I have tested in VMWare extensively, and the patch is quite minimal.
> 
> +++ linux/init/do_mounts.c      2003-08-23 17:22:59.000000000 -0400
> @@ -380,6 +380,12 @@
>         if (is_floppy && rd_doload && rd_load_disk(0))
>                 ROOT_DEV = Root_RAM0;
> 
> +#ifndef CONFIG_ROOT_NFS
> +       if (MAJOR(ROOT_DEV) == UNNAMED_MAJOR && MINOR(ROOT_DEV) == 0) {
> +               goto out;
> +       }
> +#endif
> +
>         mount_root();

It seems ugly, to say the least, to conditionalize this on
CONFIG_ROOT_NFS.  If anything it should be conditionalized on no NFS
root actually configured, which is a very different thing.

(Of course, then nfsroot should be done via initramfs...)

	-hpa
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