bug#47889: [installer image] grub-install efi fails getting canonical path to /boot/efi on dos-formatted disk

[Mathieu Othacehe]

Hello Florian,

> Can you force GPT also in 2.?  All disk partitions get removed anyway.
> Arch wiki says MSDOS layout does not work on all EFI systems
> <https://wiki.archlinux.org/index.php/EFI_system_partition#Create_the_partition>.

Well I'm not sure, if someone has an MSDOS partition table with an ESP
partition it wouldn't be a good idea to wipe it.

The attached patch forces GPT if there's no partition table, and will
preserve/create an ESP partition on an MSDOS/EFI setup. I'm testing it
on various machines, seems to work fine.

WDYT?

Thanks,

Mathieu

>From 65339286fe9d0c4758c04cfcaa177334577741cc Mon Sep 17 00:00:00 2001
From: Mathieu Othacehe <othacehe@gnu.org>
Date: Sun, 25 Apr 2021 19:06:31 +0200
Subject: [PATCH] wip esp

---
 gnu/installer/newt/partition.scm | 16 +++++++-----
 gnu/installer/parted.scm         | 45 ++++++++++++++------------------
 2 files changed, 28 insertions(+), 33 deletions(-)

diff --git a/gnu/installer/newt/partition.scm b/gnu/installer/newt/partition.scm
index 81cf68d782..2dcb10bbdb 100644
--- a/gnu/installer/newt/partition.scm
+++ b/gnu/installer/newt/partition.scm
@@ -95,14 +95,16 @@ DEVICES list."
 
 (define (run-label-page button-text button-callback)
   "Run a page asking the user to select a partition table label."
-  (run-listbox-selection-page
-   #:info-text (G_ "Select a new partition table type. \
+  (if (efi-installation?)
+      "gpt"
+      (run-listbox-selection-page
+       #:info-text (G_ "Select a new partition table type. \
 Be careful, all data on the disk will be lost.")
-   #:title (G_ "Partition table")
-   #:listbox-items '("msdos" "gpt")
-   #:listbox-item->text identity
-   #:button-text button-text
-   #:button-callback-procedure button-callback))
+       #:title (G_ "Partition table")
+       #:listbox-items '("msdos" "gpt")
+       #:listbox-item->text identity
+       #:button-text button-text
+       #:button-callback-procedure button-callback)))
 
 (define (run-type-page partition)
   "Run a page asking the user to select a partition type."
diff --git a/gnu/installer/parted.scm b/gnu/installer/parted.scm
index 9ef263d1f9..6d6e500d71 100644
--- a/gnu/installer/parted.scm
+++ b/gnu/installer/parted.scm
@@ -70,6 +70,7 @@
             small-freespace-partition?
             esp-partition?
             boot-partition?
+            efi-installation?
             default-esp-mount-point
 
             with-delay-device-in-use?
@@ -193,12 +194,8 @@ inferior to MAX-SIZE, #f otherwise."
 (define (esp-partition? partition)
   "Return #t if partition has the ESP flag, return #f otherwise."
   (let* ((disk (partition-disk partition))
-         (disk-type (disk-disk-type disk))
-         (has-extended? (disk-type-check-feature
-                         disk-type
-                         DISK-TYPE-FEATURE-EXTENDED)))
+         (disk-type (disk-disk-type disk)))
     (and (data-partition? partition)
-         (not has-extended?)
          (partition-is-flag-available? partition PARTITION-FLAG-ESP)
          (partition-get-flag partition PARTITION-FLAG-ESP))))
 
@@ -918,30 +915,26 @@ exists."
          ;; disk space. Otherwise, set the swap size to 5% of the disk space.
          (swap-size (min default-swap-size five-percent-disk)))
 
-    (if has-extended?
-        ;; msdos - remove everything.
-        (disk-remove-all-partitions disk)
-        ;; gpt - remove everything but esp if it exists.
-        (for-each
-         (lambda (partition)
-           (and (data-partition? partition)
-                (disk-remove-partition* disk partition)))
-         non-boot-partitions))
+    ;; Remove everything but esp if it exists.
+    (for-each
+     (lambda (partition)
+       (and (data-partition? partition)
+            (disk-remove-partition* disk partition)))
+     non-boot-partitions)
 
     (let* ((start-partition
-            (and (not has-extended?)
-                 (if (efi-installation?)
-                     (and (not esp-partition)
-                          (user-partition
-                           (fs-type 'fat32)
-                           (esp? #t)
-                           (size new-esp-size)
-                           (mount-point (default-esp-mount-point))))
+            (if (efi-installation?)
+                (and (not esp-partition)
                      (user-partition
-                      (fs-type 'ext4)
-                      (bootable? #t)
-                      (bios-grub? #t)
-                      (size bios-grub-size)))))
+                      (fs-type 'fat32)
+                      (esp? #t)
+                      (size new-esp-size)
+                      (mount-point (default-esp-mount-point))))
+                (user-partition
+                 (fs-type 'ext4)
+                 (bootable? #t)
+                 (bios-grub? #t)
+                 (size bios-grub-size))))
            (new-partitions
             (cond
              ((or (eq? scheme 'entire-root)
-- 
2.31.1