Add compatibility file for GRUB versions up to v2.06

cmd/zpool/Makefile.am

@@ -140,7 +140,8 @@ dist_zpoolcompat_DATA = \
 	%D%/compatibility.d/freebsd-11.2 \
 	%D%/compatibility.d/freebsd-11.3 \
 	%D%/compatibility.d/freenas-9.10.2 \
-	%D%/compatibility.d/grub2 \
+	%D%/compatibility.d/grub2-2.06 \
+	%D%/compatibility.d/grub2-2.12 \
 	%D%/compatibility.d/openzfs-2.0-freebsd \
 	%D%/compatibility.d/openzfs-2.0-linux \
 	%D%/compatibility.d/openzfs-2.1-freebsd \
@@ -171,6 +172,7 @@ zpoolcompatlinks = \
 	"freebsd-11.3		freebsd-12.2" \
 	"freebsd-11.3		freebsd-12.3" \
 	"freebsd-11.3		freebsd-12.4" \
+	"grub2-2.12		grub2" \
 	"openzfs-2.1-freebsd	freebsd-13.0" \
 	"openzfs-2.1-freebsd	freebsd-13.1" \
 	"openzfs-2.1-freebsd	freebsd-13.2" \

cmd/zpool/compatibility.d/grub2-2.06

@@ -0,0 +1,23 @@
+# Features which are supported by GRUB2 versions prior to v2.12.
+#
+# GRUB is not able to detect ZFS pool if snaphsot of top level boot pool
+# is created. This issue is observed with GRUB versions before v2.12 if
+# extensible_dataset feature is enabled on ZFS boot pool.
+#
+# This file lists all read-only comaptible features except
+# extensible_dataset and any other feature that depends on it.
+#
+allocation_classes
+async_destroy
+block_cloning
+device_rebuild
+embedded_data
+empty_bpobj
+enabled_txg
+hole_birth
+log_spacemap
+lz4_compress
+resilver_defer
+spacemap_histogram
+spacemap_v2
+zpool_checkpoint

cmd/zpool/compatibility.d/grub2 → cmd/zpool/compatibility.d/grub2-2.12

@@ -1,4 +1,4 @@
-# Features which are supported by GRUB2
+# Features which are supported by GRUB2 versions from v2.12 onwards.
 allocation_classes
 async_destroy
 block_cloning

man/man7/zpool-features.7

@@ -219,7 +219,7 @@ to the end of the line is ignored.
 .Sy Example :
 .Bd -literal -compact -offset 4n
 .No example# Nm cat Pa /usr/share/zfs/compatibility.d/grub2
-# Features which are supported by GRUB2
+# Features which are supported by GRUB2 versions from v2.12 onwards.
 allocation_classes
 async_destroy
 block_cloning
@@ -243,6 +243,31 @@ userobj_accounting
 zilsaxattr
 zpool_checkpoint
 
+.No example# Nm cat Pa /usr/share/zfs/compatibility.d/grub2-2.06
+# Features which are supported by GRUB2 versions prior to v2.12.
+#
+# GRUB is not able to detect ZFS pool if snaphsot of top level boot pool
+# is created. This issue is observed with GRUB versions before v2.12 if
+# extensible_dataset feature is enabled on ZFS boot pool.
+#
+# This file lists all read-only comaptible features except
+# extensible_dataset and any other feature that depends on it.
+#
+allocation_classes
+async_destroy
+block_cloning
+device_rebuild
+embedded_data
+empty_bpobj
+enabled_txg
+hole_birth
+log_spacemap
+lz4_compress
+resilver_defer
+spacemap_histogram
+spacemap_v2
+zpool_checkpoint
+
 .No example# Nm zpool Cm create Fl o Sy compatibility Ns = Ns Ar grub2 Ar bootpool Ar vdev
 .Ed
 .Pp
@@ -681,7 +706,7 @@ are destroyed.
 Large dnodes allow more data to be stored in the bonus buffer,
 thus potentially improving performance by avoiding the use of spill blocks.
 .
-.feature com.delphix livelist yes
+.feature com.delphix livelist yes extensible_dataset
 This feature allows clones to be deleted faster than the traditional method
 when a large number of random/sparse writes have been made to the clone.
 All blocks allocated and freed after a clone is created are tracked by the

tests/zfs-tests/tests/functional/cli_root/zpool_create/zpool_create.shlib

@@ -119,9 +119,8 @@ function check_feature_set
 	while read line; do
 		typeset flag=1
 
-		if [[ "$line" == "#*" ]]; then
-			continue
-		fi
+		# Skip comments
+		[[ $line = \#* ]] && continue
 
 		for set in "$@"; do
 			if ! grep -q "$line" $ZPOOL_COMPAT_DIR/$set; then