From af2946358849ac01ee3a40b79f74c3cc989d6640 Mon Sep 17 00:00:00 2001
From: lassulus <lassulus@lassul.us>
Date: Mon, 22 Aug 2022 16:56:44 +0200
Subject: use /dev/disk/by-path for better nvme support

---
 lib/default.nix | 56 +++++++++++++++++++++++++++++++++++++++++++++-----------
 1 file changed, 45 insertions(+), 11 deletions(-)

(limited to 'lib')

diff --git a/lib/default.nix b/lib/default.nix
index 66e667a..62aed38 100644
--- a/lib/default.nix
+++ b/lib/default.nix
@@ -9,6 +9,31 @@ let {
   body.mount = mount-f {};
 
 
+  helper.find-device = device: let
+    environment = helper.device-id device;
+  in ''
+    if echo '${device}' | grep -q '^/dev/disk'; then
+      # DEVICE points already to /dev/disk, so we don't handle it via /dev/disk/by-path
+      ${environment}='${device}'
+    else
+      ${environment}=$(for x in /dev/disk/by-path/*; do
+        dev=$x
+        if [ "$(readlink -f $x)" = '${device}' ]; then
+          target=$dev
+          break
+        fi
+      done
+      if test -z $target; then
+        echo 'unable to find path of disk: ${device}, bailing out' >&2
+        exit 1
+      else
+        echo $target
+      fi)
+    fi
+  '';
+
+  helper.device-id = device: "DEVICE${builtins.substring 0 5 (builtins.hashString "sha1" device)}";
+
   config-f = q: x: config.${x.type} q x;
 
   config.filesystem = q: x: {
@@ -70,19 +95,24 @@ let {
 
   create.noop = q: x: "";
 
-  create.partition = q: x: ''
-    parted -s ${q.device} mkpart ${x.part-type} ${x.fs-type or ""} ${x.start} ${x.end}
+  create.partition = q: x: let
+    env = helper.device-id q.device;
+  in ''
+    parted -s "''${${env}}" mkpart ${x.part-type} ${x.fs-type or ""} ${x.start} ${x.end}
+    # ensure /dev/disk/by-path/..-partN exists before continuing
+    udevadm trigger --subsystem-match=block; udevadm settle
     ${optionalString (x.bootable or false) ''
-      parted -s ${q.device} set ${toString q.index} boot on
+      parted -s "''${${env}}" set ${toString q.index} boot on
     ''}
     ${concatMapStringsSep "" (flag: ''
-      parted -s ${q.device} set ${toString q.index} ${flag} on
+      parted -s "''${${env}}" set ${toString q.index} ${flag} on
     '') (x.flags or [])}
-    ${create-f { device = q.device + toString q.index; } x.content}
+    ${create-f { device = "\"\${${env}}\"-part" + toString q.index; } x.content}
   '';
 
   create.table = q: x: ''
-    parted -s ${q.device} mklabel ${x.format}
+    ${helper.find-device q.device}
+    parted -s "''${${helper.device-id q.device}}" mklabel ${x.format}
     ${concatStrings (imap (index: create-f (q // { inherit index; })) x.partitions)}
   '';
 
@@ -91,8 +121,8 @@ let {
 
   mount.filesystem = q: x: {
       fs.${x.mountpoint} = ''
-        if ! findmnt "${q.device}" "/mnt${x.mountpoint}" > /dev/null 2>&1; then
-          mount "${q.device}" "/mnt${x.mountpoint}" -o X-mount.mkdir
+        if ! findmnt ${q.device} "/mnt${x.mountpoint}" > /dev/null 2>&1; then
+          mount ${q.device} "/mnt${x.mountpoint}" -o X-mount.mkdir
         fi
       '';
     };
@@ -102,6 +132,7 @@ let {
     # attrValues returns values sorted by name.  This is important, because it
     # ensures that "/" is processed before "/foo" etc.
   in ''
+    ${optionalString (hasAttr "table" z) (concatStringsSep "\n" (attrValues z.table))}
     ${optionalString (hasAttr "luks" z) (concatStringsSep "\n" (attrValues z.luks))}
     ${optionalString (hasAttr "lvm" z) (concatStringsSep "\n" (attrValues z.lvm))}
     ${optionalString (hasAttr "fs" z) (concatStringsSep "\n" (attrValues z.fs))}
@@ -129,8 +160,11 @@ let {
   mount.noop = q: x: {};
 
   mount.partition = q: x:
-    mount-f { device = q.device + toString q.index; } x.content;
+    mount-f { device = "\"\${${helper.device-id q.device}}\"-part" + toString q.index; } x.content;
 
-  mount.table = q: x:
-    foldl' recursiveUpdate {} (imap (index: mount-f (q // { inherit index; })) x.partitions);
+  mount.table = q: x: (
+    recursiveUpdate
+    (foldl' recursiveUpdate {} (imap (index: mount-f (q // { inherit index; device = helper.device-id q.device; })) x.partitions))
+    {table.${q.device} = helper.find-device q.device;}
+  );
 }
-- 
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