diff mbox series

[v3] rootfs: Fix support for rootfstype= when root= is given

Message ID 20231120011248.396012-1-stefanb@linux.ibm.com
State New
Headers
Series [v3] rootfs: Fix support for rootfstype= when root= is given |

Commit Message

Stefan Berger Nov. 20, 2023, 1:12 a.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 rootfstype= is ignored. Therefore,
ramfs is currently always chosen when root= is provided.

The current behavior for rootfs's filesystem is:

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

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

   root=       | rootfstype= | 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")
Cc: <stable@vger.kernel.org>
Signed-off-by: Rob Landley <rob@landley.net>
Link: https://lore.kernel.org/lkml/8244c75f-445e-b15b-9dbf-266e7ca666e2@landley.net/
Signed-off-by: Stefan Berger <stefanb@linux.ibm.com>

---

v3:
 - Changed initfstype= to rootfstype=
 - Remove my R-b

v2:
 - Cc'ing stable mailing list now
---
 init/do_mounts.c | 9 ++++++---
 1 file changed, 6 insertions(+), 3 deletions(-)

Comments

Greg KH Nov. 28, 2023, 9:54 a.m. UTC | #1 
On Sun, Nov 19, 2023 at 08:12:48PM -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 rootfstype= is ignored. Therefore,
> ramfs is currently always chosen when root= is provided.
> 
> The current behavior for rootfs's filesystem is:
> 
>    root=       | rootfstype= | chosen rootfs filesystem
>    ------------+-------------+--------------------------
>    unspecified | unspecified | tmpfs
>    unspecified | tmpfs       | tmpfs
>    unspecified | ramfs       | ramfs
>     provided   | ignored     | ramfs
> 
> rootfstype= should be respected regardless whether root= is given,
> as shown below:
> 
>    root=       | rootfstype= | 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")
> Cc: <stable@vger.kernel.org>
> Signed-off-by: Rob Landley <rob@landley.net>
> Link: https://lore.kernel.org/lkml/8244c75f-445e-b15b-9dbf-266e7ca666e2@landley.net/
> Signed-off-by: Stefan Berger <stefanb@linux.ibm.com>

Acked-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

Who should take this patch?  Me?  Or someone else?

thanks,

greg k-h
Mimi Zohar Nov. 28, 2023, 12:18 p.m. UTC | #2 
On Tue, 2023-11-28 at 09:54 +0000, Greg KH wrote:
> On Sun, Nov 19, 2023 at 08:12:48PM -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 rootfstype= is ignored. Therefore,
> > ramfs is currently always chosen when root= is provided.
> > 
> > The current behavior for rootfs's filesystem is:
> > 
> >    root=       | rootfstype= | chosen rootfs filesystem
> >    ------------+-------------+--------------------------
> >    unspecified | unspecified | tmpfs
> >    unspecified | tmpfs       | tmpfs
> >    unspecified | ramfs       | ramfs
> >     provided   | ignored     | ramfs
> > 
> > rootfstype= should be respected regardless whether root= is given,
> > as shown below:
> > 
> >    root=       | rootfstype= | 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")
> > Cc: <stable@vger.kernel.org>
> > Signed-off-by: Rob Landley <rob@landley.net>
> > Link: https://lore.kernel.org/lkml/8244c75f-445e-b15b-9dbf-266e7ca666e2@landley.net/
> > Signed-off-by: Stefan Berger <stefanb@linux.ibm.com>
> 
> Acked-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
> 
> Who should take this patch?  Me?  Or someone else?

Reviewed-and-Tested-by: Mimi Zohar <zohar@linux.ibm.com>

Thanks, Greg.  As there is no initramfs maintainer, I'd appreciate your
picking it up.
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;
+	}
 }