[PATCH] zfs: fix root dataset detection on encrypted pools

[PATCH] zfs: fix root dataset detection on encrypted pools

[Christian Schoenebeck via Grub-devel]

grub-probe fails on encrypted zfs pools, causing $rpool variable
to be empty. Therefore check variables $rpool and $bootfs to
be both non-empty strings before assembling LINUX_ROOT_DEVICE.

If one of the two variables is empty, use "zfs list" as fallback
for detecting the zfs root dataset instead.

Signed-off-by: Christian Schoenebeck <linux_oss@crudebyte.com>
---
 util/grub.d/10_linux.in | 8 +++++++-
 1 file changed, 7 insertions(+), 1 deletion(-)

diff --git a/util/grub.d/10_linux.in b/util/grub.d/10_linux.in
index 07649cd3b..acbd2ab64 100644
--- a/util/grub.d/10_linux.in
+++ b/util/grub.d/10_linux.in
@@ -75,7 +75,13 @@ case x"$GRUB_FS" in
     xzfs)
 	rpool=`${grub_probe} --device ${GRUB_DEVICE} --target=fs_label 2>/dev/null || zdb -l ${GRUB_DEVICE} | awk -F \' '/ name/ { print $2 }'`
 	bootfs="`make_system_path_relative_to_its_root / | sed -e "s,@$,,"`"
-	LINUX_ROOT_DEVICE="ZFS=${rpool}${bootfs%/}"
+	# grub-probe fails on encrypted zfs pools, use zfs list as fallback
+	if [ -n "$rpool" ] && [ -n "$bootfs" ]; then
+	    LINUX_ROOT_DEVICE="ZFS=${rpool}${bootfs%/}"
+	else
+	    root_dataset=`zfs list -Ho mountpoint,name | grep '^/[[:space:]]' | tail -n1 | cut -f 2 2>/dev/null || true`
+	    LINUX_ROOT_DEVICE="ZFS=${root_dataset}"
+	fi
 	;;
 esac
 
-- 
2.47.3


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Re: [PATCH] zfs: fix root dataset detection on encrypted pools

[Christian Schoenebeck via Grub-devel]

On Monday, 9 February 2026 19:56:00 CET Christian Schoenebeck wrote:
> grub-probe fails on encrypted zfs pools, causing $rpool variable
> to be empty. Therefore check variables $rpool and $bootfs to
> be both non-empty strings before assembling LINUX_ROOT_DEVICE.
> 
> If one of the two variables is empty, use "zfs list" as fallback
> for detecting the zfs root dataset instead.
> 
> Signed-off-by: Christian Schoenebeck <linux_oss@crudebyte.com>
> ---
>  util/grub.d/10_linux.in | 8 +++++++-
>  1 file changed, 7 insertions(+), 1 deletion(-)

Ping, anyone?

/Christian

> diff --git a/util/grub.d/10_linux.in b/util/grub.d/10_linux.in
> index 07649cd3b..acbd2ab64 100644
> --- a/util/grub.d/10_linux.in
> +++ b/util/grub.d/10_linux.in
> @@ -75,7 +75,13 @@ case x"$GRUB_FS" in
>      xzfs)
>         rpool=`${grub_probe} --device ${GRUB_DEVICE} --target=fs_label 2>/dev/null || zdb -l ${GRUB_DEVICE} | awk -F \' '/ name/ { print $2 }'`
>         bootfs="`make_system_path_relative_to_its_root / | sed -e "s,@$,,"`"
> -       LINUX_ROOT_DEVICE="ZFS=${rpool}${bootfs%/}"
> +       # grub-probe fails on encrypted zfs pools, use zfs list as fallback
> +       if [ -n "$rpool" ] && [ -n "$bootfs" ]; then
> +           LINUX_ROOT_DEVICE="ZFS=${rpool}${bootfs%/}"
> +       else
> +           root_dataset=`zfs list -Ho mountpoint,name | grep '^/[[:space:]]' | tail -n1 | cut -f 2 2>/dev/null || true`
> +           LINUX_ROOT_DEVICE="ZFS=${root_dataset}"
> +       fi
>         ;;
>  esac
>  
> -- 
> 2.47.3



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Re: [PATCH] zfs: fix root dataset detection on encrypted pools

[Christian Schoenebeck via Grub-devel]

On Wednesday, 18 February 2026 11:28:18 CET Christian Schoenebeck wrote:
> On Monday, 9 February 2026 19:56:00 CET Christian Schoenebeck wrote:
> > grub-probe fails on encrypted zfs pools, causing $rpool variable
> > to be empty. Therefore check variables $rpool and $bootfs to
> > be both non-empty strings before assembling LINUX_ROOT_DEVICE.
> > 
> > If one of the two variables is empty, use "zfs list" as fallback
> > for detecting the zfs root dataset instead.
> > 
> > Signed-off-by: Christian Schoenebeck <linux_oss@crudebyte.com>
> > ---
> > 
> >  util/grub.d/10_linux.in | 8 +++++++-
> >  1 file changed, 7 insertions(+), 1 deletion(-)

Ping

> Ping, anyone?
> 
> /Christian
> 
> > diff --git a/util/grub.d/10_linux.in b/util/grub.d/10_linux.in
> > index 07649cd3b..acbd2ab64 100644
> > --- a/util/grub.d/10_linux.in
> > +++ b/util/grub.d/10_linux.in
> > @@ -75,7 +75,13 @@ case x"$GRUB_FS" in
> >      xzfs)
> >         rpool=`${grub_probe} --device ${GRUB_DEVICE} --target=fs_label 2>/dev/null || zdb -l ${GRUB_DEVICE} | awk -F \' '/ name/ { print $2 }'`
> >         bootfs="`make_system_path_relative_to_its_root / | sed -e "s,@$,,"`"
> > -       LINUX_ROOT_DEVICE="ZFS=${rpool}${bootfs%/}"
> > +       # grub-probe fails on encrypted zfs pools, use zfs list as fallback
> > +       if [ -n "$rpool" ] && [ -n "$bootfs" ]; then
> > +           LINUX_ROOT_DEVICE="ZFS=${rpool}${bootfs%/}"
> > +       else
> > +           root_dataset=`zfs list -Ho mountpoint,name | grep '^/[[:space:]]' | tail -n1 | cut -f 2 2>/dev/null || true`
> > +           LINUX_ROOT_DEVICE="ZFS=${root_dataset}"
> > +       fi
> >         ;;
> >  esac
> >  
> > -- 
> > 2.47.3



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