Make alt-w a toggle between R/O and R/W imports

Author: ahesford

90zfsbootmenu/zfsbootmenu-lib.sh

@@ -237,7 +237,7 @@ kexec_kernel() {
 
   # Export if read-write, to ensure a clean pool
   pool="${selected%%/*}"
-  if [ "$( zpool get -H -o value readonly "${pool}" )" = "off" ]; then
+  if is_writable "${pool}"; then
     export_pool "${pool}"
   fi
 
@@ -853,6 +853,27 @@ resume_prompt() {
   return 0
 }
 
+# arg1: pool name
+# prints nothing
+# returns: 0 when pool is writable, 1 otherwise
+
+is_writable() {
+  local pool roflag
+
+  pool="${1}"
+  [ -n "${pool}" ] || return 1
+
+  # Pool is not writable if the property can't be read
+  roflag="$( zpool get -H -o value readonly "${pool}" 2>/dev/null )" || return 1
+
+  if [ "x${roflag}" = "xoff" ]; then
+    return 0
+  fi
+
+  # Otherwise, pool is not writable
+  return 1
+}
+
 # arg1: pool name
 # prints: nothing
 # returns: 0 on success, 1 on failure
@@ -863,15 +884,15 @@ set_rw_pool() {
   pool="${1}"
   [ -n "${pool}" ] || return 1
 
+  # If force_export is set, skip evaluating if the pool is already read-write
+  # shellcheck disable=SC2154
+  [ -n "${force_export}" ] || ! is_writable "${pool}" || return 0
+
   if grep -q "${pool}" "${BASE}/degraded" >/dev/null 2>&1; then
     color=red delay=10 timed_prompt "Operation prohibited" "Pool '${pool}' cannot be imported read-write"
     return 1
   fi
 
-  # If force_export is set, skip evaluating if the pool is already read-write
-  # shellcheck disable=SC2154
-  [ -n "${force_export}" ] || [ "x$( zpool get -H -o value readonly "${pool}" )" = "xon" ] || return 0
-
   resume_prompt "${pool}" || return 1
 
   if export_pool "${pool}" ; then

90zfsbootmenu/zfsbootmenu.sh

@@ -126,8 +126,8 @@ if [[ -n "${BOOTFS}" ]]; then
       tput clear
       if ! key_wrapper "${BOOTFS}" ; then
         emergency_shell "unable to load required key for ${BOOTFS}"
-      elif  find_be_kernels "${BOOTFS}" ; then
-      # Automatically select a kernel and boot it
+      elif find_be_kernels "${BOOTFS}" ; then
+        # Automatically select a kernel and boot it
         kexec_kernel "$( select_kernel "${BOOTFS}" )"
       fi
     fi
@@ -256,14 +256,14 @@ while true; do
           ;;
           # Check available space early in the process
           "enter")
-            avail_space_exact="$( zfs list -p -H -o available "${selected_snap%/*}" )"
+            avail_space_exact="$( zfs list -p -H -o available "${parent_ds}" )"
             be_size_exact="$( zfs list -p -H -o refer "${selected_snap}" )"
             leftover_space=$(( avail_space_exact - be_size_exact ))
             if [ "${leftover_space}" -le 0 ]; then
-              avail_space="$( zfs list -H -o available "${selected_snap%/*}" )"
+              avail_space="$( zfs list -H -o available "${parent_ds}" )"
               be_size="$( zfs list -H -o refer "${selected_snap}" )"
               color=red delay=10 timed_prompt "Insufficient space for duplication" \
-                "'${selected_snap%/*}' has ${avail_space} free but needs ${be_size}"
+                "'${parent_ds}' has ${avail_space} free but needs ${be_size}"
               continue
             fi
           ;;
@@ -322,7 +322,17 @@ while true; do
         ;;
       "alt-w")
         pool="${selected_be%%/*}"
-        if set_rw_pool "${pool}"; then
+        need_key=''
+
+        if is_writable "${pool}"; then
+          if export_pool "${pool}" && read_write='' import_pool "${pool}"; then
+            need_key=1
+          fi
+        elif set_rw_pool "${pool}"; then
+          need_key=1
+        fi
+
+        if [ -n "${need_key}" ]; then
           CLEAR_SCREEN=1 key_wrapper "${pool}"
         fi
         ;;