diff mbox series

rootfs: Fix support for rootfstype= when root= is given

Message ID 20231113211735.23267-1-stefanb@linux.ibm.com
State New
Headers
Series rootfs: Fix support for rootfstype= when root= is given |

Commit Message

Stefan Berger Nov. 13, 2023, 9:17 p.m. UTC 
  Documentation/filesystems/ramfs-rootfs-initramfs.rst states:

  If CONFIG_TMPFS is enabled, rootfs will use tmpfs instead of ramfs by
  default.  To force ramfs, add "rootfstype=ramfs" to the kernel command
  line.

This currently does not work when root= is provided since then
saved_root_name contains a string and initfstype= is ignored. Therefore,
ramfs is currently always chosen when root= is provided.

The current behavior for rootfs's filesystem is:

   root=       | initfstype= | chosen rootfs filesystem
   ------------+-------------+--------------------------
   unspecified | unspecified | tmpfs
   unspecified | tmpfs       | tmpfs
   unspecified | ramfs       | ramfs
    provided   | ignored     | ramfs

initfstype= should be respected regardless whether root= is given,
as shown below:

   root=       | initfstype= | chosen rootfs filesystem
   ------------+-------------+--------------------------
   unspecified | unspecified | tmpfs  (as before)
   unspecified | tmpfs       | tmpfs  (as before)
   unspecified | ramfs       | ramfs  (as before)
    provided   | unspecified | ramfs  (compatibility with before)
    provided   | tmpfs       | tmpfs  (new)
    provided   | ramfs       | ramfs  (new)

This table represents the new behavior.

Fixes: 6e19eded3684 ("initmpfs: use initramfs if rootfstype= or root=  specified")
Reviewed-by: Stefan Berger <stefanb@linux.ibm.com>
Signed-off-by: Rob Landley <rob@landley.net>
Signed-off-by: Stefan Berger <stefanb@linux.ibm.com>
---
 init/do_mounts.c | 9 ++++++---
 1 file changed, 6 insertions(+), 3 deletions(-)

Comments

Greg KH Nov. 14, 2023, 1:19 p.m. UTC | #1 
On Mon, Nov 13, 2023 at 04:17:35PM -0500, Stefan Berger wrote:
> Documentation/filesystems/ramfs-rootfs-initramfs.rst states:
> 
>   If CONFIG_TMPFS is enabled, rootfs will use tmpfs instead of ramfs by
>   default.  To force ramfs, add "rootfstype=ramfs" to the kernel command
>   line.
> 
> This currently does not work when root= is provided since then
> saved_root_name contains a string and initfstype= is ignored. Therefore,
> ramfs is currently always chosen when root= is provided.
> 
> The current behavior for rootfs's filesystem is:
> 
>    root=       | initfstype= | chosen rootfs filesystem
>    ------------+-------------+--------------------------
>    unspecified | unspecified | tmpfs
>    unspecified | tmpfs       | tmpfs
>    unspecified | ramfs       | ramfs
>     provided   | ignored     | ramfs
> 
> initfstype= should be respected regardless whether root= is given,
> as shown below:
> 
>    root=       | initfstype= | chosen rootfs filesystem
>    ------------+-------------+--------------------------
>    unspecified | unspecified | tmpfs  (as before)
>    unspecified | tmpfs       | tmpfs  (as before)
>    unspecified | ramfs       | ramfs  (as before)
>     provided   | unspecified | ramfs  (compatibility with before)
>     provided   | tmpfs       | tmpfs  (new)
>     provided   | ramfs       | ramfs  (new)
> 
> This table represents the new behavior.
> 
> Fixes: 6e19eded3684 ("initmpfs: use initramfs if rootfstype= or root=  specified")
> Reviewed-by: Stefan Berger <stefanb@linux.ibm.com>
> Signed-off-by: Rob Landley <rob@landley.net>
> Signed-off-by: Stefan Berger <stefanb@linux.ibm.com>
> ---
>  init/do_mounts.c | 9 ++++++---
>  1 file changed, 6 insertions(+), 3 deletions(-)
> 

Hi,

This is the friendly patch-bot of Greg Kroah-Hartman.  You have sent him
a patch that has triggered this response.  He used to manually respond
to these common problems, but in order to save his sanity (he kept
writing the same thing over and over, yet to different people), I was
created.  Hopefully you will not take offence and will fix the problem
in your patch and resubmit it so that it can be accepted into the Linux
kernel tree.

You are receiving this message because of the following common error(s)
as indicated below:

- You have marked a patch with a "Fixes:" tag for a commit that is in an
  older released kernel, yet you do not have a cc: stable line in the
  signed-off-by area at all, which means that the patch will not be
  applied to any older kernel releases.  To properly fix this, please
  follow the documented rules in the
  Documentation/process/stable-kernel-rules.rst file for how to resolve
  this.

If you wish to discuss this problem further, or you have questions about
how to resolve this issue, please feel free to respond to this email and
Greg will reply once he has dug out from the pending patches received
from other developers.

thanks,

greg k-h's patch email bot
diff mbox series

Patch

diff --git a/init/do_mounts.c b/init/do_mounts.c
index 5fdef94f0864..279ad28bf4fb 100644
--- a/init/do_mounts.c
+++ b/init/do_mounts.c
@@ -510,7 +510,10 @@  struct file_system_type rootfs_fs_type = {
 
 void __init init_rootfs(void)
 {
-	if (IS_ENABLED(CONFIG_TMPFS) && !saved_root_name[0] &&
-		(!root_fs_names || strstr(root_fs_names, "tmpfs")))
-		is_tmpfs = true;
+	if (IS_ENABLED(CONFIG_TMPFS)) {
+		if (!saved_root_name[0] && !root_fs_names)
+			is_tmpfs = true;
+		else if (root_fs_names && !!strstr(root_fs_names, "tmpfs"))
+			is_tmpfs = true;
+	}
 }