zfsbootmenu: add zbm.bootfs parameter

Author: zdykstra

zfsbootmenu/init.d/50-import-pools

@@ -105,17 +105,25 @@ if [ "${unsupported}" -ne 0 ]; then
 fi
 unset unsupported
 
-# Attempt to find the bootfs property
-# shellcheck disable=SC2086
-while read -r _bootfs; do
-  if [ "${_bootfs}" = "-" ]; then
-    BOOTFS=
+if [ -n "${zbm_prefer_bootfs}" ]; then
+  if is_zfs_filesystem "${zbm_prefer_bootfs}" ; then
+    BOOTFS="${zbm_prefer_bootfs}"
   else
-    BOOTFS="${_bootfs}"
-    break
+    zerror "zbm.bootfs value '${zbm_prefer_bootfs}' not a ZFS dataset"
   fi
-done <<<"$( zpool list -H -o bootfs "${zbm_prefer_pool:---}" )"
-unset _bootfs
+else
+  # Attempt to find the bootfs property
+  # shellcheck disable=SC2086
+  while read -r _bootfs; do
+    if [ "${_bootfs}" = "-" ]; then
+      BOOTFS=
+    else
+      BOOTFS="${_bootfs}"
+      break
+    fi
+  done <<<"$( zpool list -H -o bootfs "${zbm_prefer_pool:---}" )"
+  unset _bootfs
+fi
 
 if [ -n "${BOOTFS}" ]; then
   export BOOTFS

zfsbootmenu/pre-init/zfsbootmenu-parse-commandline.sh

@@ -219,30 +219,40 @@ if kcl_override=$( get_zbm_arg zbm.kcl_override ) ; then
   zinfo "overriding all BE KCLs with: '$( kcl_assemble < "${BASE}/cmdline" )'"
 fi
 
-zbm_prefer_pool=
-if zbm_prefer_pool=$( get_zbm_arg zbm.prefer ) ; then
-  # shellcheck disable=SC2034
-  zbm_prefer_pool="${zbm_prefer_pool%%/*}"
-  zinfo "preferring ${zbm_prefer_pool} for bootfs"
-fi
-
 zbm_wait_for_devices=
 if zbm_wait_for_devices=$( get_zbm_arg zbm.wait_for ) ; then
   zinfo "system will wait for ${zbm_wait_for_devices}"
 fi
 
-# pool! : this pool must be imported before all others
-# pool!!: this pool, and no others, must be imported
+zbm_prefer_bootfs=
+if zbm_prefer_bootfs=$( get_zbm_arg zbm.bootfs ) ; then
+  zinfo "using ${zbm_prefer_bootfs} for bootfs"
+fi
+
+zbm_prefer_pool=
+if zbm_prefer_pool=$( get_zbm_arg zbm.prefer ) ; then
+  # shellcheck disable=SC2034
+  zbm_prefer_pool="${zbm_prefer_pool%%/*}"
+  [ -z  "${zbm_prefer_bootfs}" ] && zinfo "preferring ${zbm_prefer_pool} for bootfs"
+fi
 
 # shellcheck disable=SC2034
 case "${zbm_prefer_pool}" in
   *!!)
     zbm_require_pool="only"
     zbm_prefer_pool="${zbm_prefer_pool%!!}"
+    zinfo "will only attempt to import ${zbm_prefer_pool}"
+
+    if [ -n "${zbm_prefer_bootfs}" ] && [ "${zbm_prefer_pool}" != "${zbm_prefer_bootfs%%/*}" ]; then
+      zerror "zbm.bootfs '${zbm_prefer_bootfs}' not on the exclusive pool import"
+      unset zbm_prefer_bootfs
+    fi
+
     ;;
   *!)
     zbm_require_pool="yes"
     zbm_prefer_pool="${zbm_prefer_pool%!}"
+    zinfo "requiring pool ${zbm_prefer_pool}"
     ;;
   *)
     zbm_require_pool=""

zfsbootmenu/pre-init/zfsbootmenu-preinit.sh

@@ -28,6 +28,7 @@ export menu_timeout='${menu_timeout}'
 export loglevel='${loglevel}'
 export zbm_prefer_pool='${zbm_prefer_pool}'
 export zbm_require_pool='${zbm_require_pool}'
+export zbm_prefer_bootfs='${zbm_prefer_bootfs}'
 export default_hostid=00bab10c
 export zbm_sort='${zbm_sort}'
 export zbm_set_hostid='${zbm_set_hostid}'