[PATCH] zfs: fix LINUX_ROOT_DEVICE when grub-probe fails

* [PATCH] zfs: fix LINUX_ROOT_DEVICE when grub-probe fails
@ 2020-12-18  2:27 Doug Goldstein
  2020-12-18 13:38 ` Daniel Kiper
  2020-12-23 23:29 ` Daniel Kiper
  0 siblings, 2 replies; 4+ messages in thread
From: Doug Goldstein @ 2020-12-18  2:27 UTC (permalink / raw)
  To: grub-devel
  Cc: Richard Laager, Vladimir Serbinenko, Colin Watson, Doug Goldstein

When grub-probe fails, the current code is to just stuff an empty result
in which causes the user to not knowingly have a system that no longer
boots. grub-probe can fail because the ZFS pool that contains the root
filesystem might have features that grub does not yet support which is a
common configuration for people with a rpool and a bpool. This behavior
uses the zdb utility to dump the same value as the filesystem label
would print.

Signed-off-by: Doug Goldstein <cardoe@cardoe.com>
---
 util/grub.d/10_linux.in     | 2 +-
 util/grub.d/20_linux_xen.in | 2 +-
 2 files changed, 2 insertions(+), 2 deletions(-)

diff --git a/util/grub.d/10_linux.in b/util/grub.d/10_linux.in
index e8b01c0d0..33a25ba8f 100644
--- a/util/grub.d/10_linux.in
+++ b/util/grub.d/10_linux.in
@@ -71,7 +71,7 @@ case x"$GRUB_FS" in
 	    GRUB_CMDLINE_LINUX="rootflags=subvol=${rootsubvol} ${GRUB_CMDLINE_LINUX}"
 	fi;;
     xzfs)
-	rpool=`${grub_probe} --device ${GRUB_DEVICE} --target=fs_label 2>/dev/null || true`
+	rpool=`${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%/}"
 	;;
diff --git a/util/grub.d/20_linux_xen.in b/util/grub.d/20_linux_xen.in
index 3b1f47049..96210c24d 100644
--- a/util/grub.d/20_linux_xen.in
+++ b/util/grub.d/20_linux_xen.in
@@ -79,7 +79,7 @@ case x"$GRUB_FS" in
 	    GRUB_CMDLINE_LINUX="rootflags=subvol=${rootsubvol} ${GRUB_CMDLINE_LINUX}"
 	fi;;
     xzfs)
-	rpool=`${grub_probe} --device ${GRUB_DEVICE} --target=fs_label 2>/dev/null || true`
+	rpool=`${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%/}"
 	;;
-- 
2.24.3 (Apple Git-128)



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