lvm_vg: add lvm thinpool/thinlv support

Co-authored-by: ajs124 <git@ajs124.de>

example/lvm-thin.nix

@@ -0,0 +1,71 @@
+{
+  disko.devices = {
+    disk = {
+      vdb = {
+        type = "disk";
+        device = "/dev/vdb";
+        content = {
+          type = "gpt";
+          partitions = {
+            ESP = {
+              size = "500M";
+              type = "EF00";
+              content = {
+                type = "filesystem";
+                format = "vfat";
+                mountpoint = "/boot";
+                mountOptions = [
+                  "defaults"
+                ];
+              };
+            };
+            primary = {
+              size = "100%";
+              content = {
+                type = "lvm_pv";
+                vg = "mainpool";
+              };
+            };
+          };
+        };
+      };
+    };
+    lvm_vg = {
+      mainpool = {
+        type = "lvm_vg";
+        lvs = {
+          thinpool = {
+            size = "100M";
+            lvm_type = "thin-pool";
+          };
+          root = {
+            size = "10M";
+            lvm_type = "thinlv";
+            pool = "thinpool";
+            content = {
+              type = "filesystem";
+              format = "ext4";
+              mountpoint = "/";
+              mountOptions = [
+                "defaults"
+              ];
+            };
+          };
+          home = {
+            size = "10M";
+            lvm_type = "thinlv";
+            pool = "thinpool";
+            content = {
+              type = "filesystem";
+              format = "ext4";
+              mountpoint = "/home";
+            };
+          };
+          raw = {
+            size = "10M";
+          };
+        };
+      };
+    };
+  };
+}

lib/types/lvm_vg.nix

@@ -1,4 +1,10 @@
 { config, options, lib, diskoLib, ... }:
+let
+  # Load kernel modules to ensure device mapper types are available
+  kernelModules = lib.filter (x: x != "") (map
+    (lv: lib.optionalString (lv.lvm_type != null && lv.lvm_type != "thinlv") "dm-${lv.lvm_type}")
+  (lib.attrValues config.lvs));
+in
 {
   options = {
     name = lib.mkOption {
@@ -21,7 +27,7 @@
           };
           priority = lib.mkOption {
             type = lib.types.int;
-            default = if (lib.hasInfix "100%" lv.config.size) then 9001 else 1000;
+            default = (if lv.config.lvm_type == "thin-pool" then 501 else 1000) + (if lib.hasInfix "100%" lv.config.size then 251 else 0);
             defaultText = lib.literalExpression ''
               if (lib.hasInfix "100%" lv.config.size) then 9001 else 1000
             '';
@@ -33,7 +39,7 @@
           };
           lvm_type = lib.mkOption {
             # TODO: add raid10
-            type = lib.types.nullOr (lib.types.enum [ "mirror" "raid0" "raid1" "raid4" "raid5" "raid6" ]); # TODO add all lib.types
+            type = lib.types.nullOr (lib.types.enum [ "mirror" "raid0" "raid1" "raid4" "raid5" "raid6" "thin-pool" "thinlv" ]); # TODO add all lib.types
             default = null; # maybe there is always a default type?
             description = "LVM type";
           };
@@ -42,6 +48,11 @@
             default = [ ];
             description = "Extra arguments";
           };
+          pool = lib.mkOption {
+            type = lib.types.nullOr lib.types.str;
+            default = null;
+            description = "Name of pool LV that this LV belongs to";
+          };
           content = diskoLib.partitionType { parent = config; device = "/dev/${config.name}/${lv.config.name}"; };
         };
       }));
@@ -67,6 +78,7 @@
           sortedLvs = lib.sort (a: b: a.priority < b.priority) (lib.attrValues config.lvs);
         in
         ''
+          ${lib.concatMapStringsSep "\n" (k: ''modprobe "${k}"'') kernelModules}
           readarray -t lvm_devices < <(cat "$disko_devices_dir"/lvm_${config.name})
           if ! vgdisplay "${config.name}" >/dev/null; then
             vgcreate ${config.name} \
@@ -76,9 +88,12 @@
             if ! lvdisplay '${config.name}/${lv.name}'; then
               lvcreate \
                 --yes \
-                ${if lib.hasInfix "%" lv.size then "-l" else "-L"} ${lv.size} \
+                ${if (lv.lvm_type == "thinlv") then "-V"
+                  else if lib.hasInfix "%" lv.size then "-l" else "-L"} \
+                  ${lv.size} \
                 -n ${lv.name} \
-                ${lib.optionalString (lv.lvm_type != null) "--type=${lv.lvm_type}"} \
+                ${lib.optionalString (lv.lvm_type == "thinlv") "--thinpool=${lv.pool}"} \
+                ${lib.optionalString (lv.lvm_type != null && lv.lvm_type != "thinlv") "--type=${lv.lvm_type}"} \
                 ${toString lv.extraArgs} \
                 ${config.name}
             fi
@@ -110,7 +125,7 @@
     _config = lib.mkOption {
       internal = true;
       readOnly = true;
-      default =
+      default = [ { boot.initrd.kernelModules = kernelModules; } ] ++
         map
           (lv: [
             (lib.optional (lv.content != null) lv.content._config)

tests/lvm-thin.nix

@@ -0,0 +1,11 @@
+{ pkgs ? import <nixpkgs> { }
+, diskoLib ? pkgs.callPackage ../lib { }
+}:
+diskoLib.testLib.makeDiskoTest {
+  inherit pkgs;
+  name = "lvm-thin";
+  disko-config = ../example/lvm-thin.nix;
+  extraTestScript = ''
+    machine.succeed("mountpoint /home");
+  '';
+}