1 files changed, 53 insertions, 2 deletions
diff --git a/gnu/installer/parted.scm b/gnu/installer/parted.scm
index fcc936a391..51fa7cf9d9 100644
--- a/gnu/installer/parted.scm
+++ b/gnu/installer/parted.scm
@@ -319,6 +319,25 @@ PARTED-OBJECT field equals PARTITION, return #f if not found."
                   partition))
         user-partitions))
 
+(define (read-partition-uuid/retry file-name)
+  "Call READ-PARTITION-UUID with 5 retries spaced by 1 second.  This is useful
+if the partition table is updated by the kernel at the time this function is
+called, causing the underlying /dev to be absent."
+  (define max-retries 5)
+
+  (let loop ((retry max-retries))
+    (catch #t
+      (lambda ()
+        (read-partition-uuid file-name))
+      (lambda _
+        (if (> retry 0)
+            (begin
+              (sleep 1)
+              (loop (- retry 1)))
+            (error
+             (format #f (G_ "Could not open ~a after ~a retries~%.")
+                     file-name max-retries)))))))
+
 
 ;;
 ;; Devices
@@ -360,12 +379,44 @@ fail. See rereadpt function in wipefs.c of util-linux for an explanation."
 (define %min-device-size
   (* 2 GIBIBYTE-SIZE)) ;2GiB
 
+(define (mapped-device? device)
+  "Return #true if DEVICE is a mapped device, false otherwise."
+  (string-prefix? "/dev/dm-" device))
+
+;; TODO: Use DM_TABLE_DEPS ioctl instead of dmsetup.
+(define (mapped-device-parent-partition device)
+  "Return the parent partition path of the mapped DEVICE."
+  (let* ((command `("dmsetup" "deps" ,device "-o" "devname"))
+         (parent #f)
+         (handler
+          (lambda (input)
+            ;; We are parsing an output that should look like:
+            ;; 1 dependencies  : (sda2)
+            (let ((result
+                   (string-match "\\(([^\\)]+)\\)"
+                                 (get-string-all input))))
+              (and result
+                   (set! parent
+                         (format #f "/dev/~a"
+                                 (match:substring result 1))))))))
+    (run-external-command-with-handler handler command)
+    parent))
+
 (define (eligible-devices)
   "Return all the available devices except the install device and the devices
 which are smaller than %MIN-DEVICE-SIZE."
 
   (define the-installer-root-partition-path
-    (installer-root-partition-path))
+    (let ((root (installer-root-partition-path)))
+      (cond
+       ((mapped-device? root)
+        ;; If the partition is a mapped device (/dev/dm-X), locate the parent
+        ;; partition.  It is the case when Ventoy is used to host the
+        ;; installation image.
+        (let ((parent (mapped-device-parent-partition root)))
+          (installer-log-line "mapped device ~a -> ~a" parent root)
+          parent))
+       (else root))))
 
   (define (small-device? device)
     (let ((length (device-length device))
@@ -1108,7 +1159,7 @@ Return #t if all the statements are valid."
                (need-formatting?
                 (user-partition-need-formatting? user-partition)))
            (or need-formatting?
-               (read-partition-uuid file-name)
+               (read-partition-uuid/retry file-name)
                (raise
                 (condition
                  (&cannot-read-uuid