zfs: Allow three tries to decrypt datasets

nixos/modules/tasks/filesystems/zfs.nix

@@ -146,7 +146,14 @@ let
                 none )
                   ;;
                 prompt )
-                  ${systemd}/bin/systemd-ask-password "Enter key for $ds:" | ${cfgZfs.package}/sbin/zfs load-key "$ds"
+                  tries=3
+                  success=false
+                  while [[ $success != true ]] && [[ $tries -gt 0 ]]; do
+                    ${systemd}/bin/systemd-ask-password "Enter key for $ds:" | ${cfgZfs.package}/sbin/zfs load-key "$ds" \
+                      && success=true \
+                      || tries=$((tries - 1))
+                  done
+                  [[ $success = true ]]
                   ;;
                 * )
                   ${cfgZfs.package}/sbin/zfs load-key "$ds"