File 0001-ieee1275-support-dm-multipath-bootlist.patch of Package grub2

From 951a2d79d3685e85df8f45f6f60002ab35c8d944 Mon Sep 17 00:00:00 2001
From: Michael Chang <mchang@suse.com>
Date: Tue, 16 Dec 2025 20:17:35 +0800
Subject: [PATCH] ieee1275: support dm multipath bootlist

Currently, when grub2-install is invoked on PowerPC (unless --no-nvram
is used), it updates Open Firmware NVRAM boot-device with the Open
Firmware path of the selected boot device.

When the install device is a device-mapper multipath device, the system
may boot through more than one underlying physical path. However, GRUB
currently records only a single Open Firmware path in boot-device, so
firmware does not have alternative paths available for failover.

This patch fixes the issue by detecting dm-multipath devices and
updating boot-device with the Open Firmware paths for all underlying
physical paths.

Signed-off-by: Michael Chang <mchang@suse.com>
---
 grub-core/osdep/unix/platform.c | 115 ++++++++++++++++++++++++++++++++
 1 file changed, 115 insertions(+)

diff --git a/grub-core/osdep/unix/platform.c b/grub-core/osdep/unix/platform.c
index e8e28f3d4..733a8ec55 100644
--- a/grub-core/osdep/unix/platform.c
+++ b/grub-core/osdep/unix/platform.c
@@ -304,6 +304,112 @@ add_multiple_nvme_bootdevices (const char *install_device)
   return multipath_boot;
 }
 
+static char *
+add_multiple_dm_multipath_bootdevices (const char *devname)
+{
+  char *devdir, *device, *tmp;
+  char *ret = NULL;
+  char *sysfs_path = NULL, *sysfs_uuid = NULL, *sysfs_slaves = NULL;
+  FILE *fp = NULL;
+  char dm_uuid[sizeof ("mpath-")];
+  DIR *dp = NULL;
+  struct dirent *de;
+  char *physical_paths[8];
+  const int max_physical_path = sizeof (physical_paths) / sizeof (physical_paths[0]);
+  int num_path = 0;
+  int i;
+
+  devdir = xrealpath (devname);
+  tmp = strrchr (devdir, '/');
+  if (tmp != NULL)
+    tmp++;
+  else
+    tmp = devdir;
+  device = xstrdup (tmp);
+  *tmp = '\0';
+
+  if (device[0] != 'd' || device[1] != 'm' || device[2] != '-')
+    goto out;
+
+  sysfs_path = xasprintf ("%s%s", "/sys/block/", device);
+  sysfs_uuid = xasprintf ("%s/dm/uuid", sysfs_path);
+
+  fp = fopen(sysfs_uuid, "r");
+  if (fp == NULL)
+    goto out;
+
+  if (fread (dm_uuid, 1, sizeof (dm_uuid) - 1, fp) != sizeof (dm_uuid) - 1)
+    goto out;
+
+  dm_uuid[sizeof (dm_uuid) - 1] = '\0';
+
+  if (strcmp (dm_uuid, "mpath-") != 0)
+    goto out;
+
+  sysfs_slaves = xasprintf ("%s/slaves", sysfs_path);
+
+  dp = opendir (sysfs_slaves);
+
+  if (dp == NULL)
+    goto out;
+
+  while ((de = readdir (dp)) != NULL)
+    {
+      char *p = NULL;
+      struct stat st;
+
+      if (strcmp (de->d_name, ".") == 0 || strcmp (de->d_name, "..") == 0)
+	continue;
+
+      p = xasprintf ("%s%s", devdir, de->d_name);
+
+      if (lstat (p, &st) < 0 || ! S_ISBLK (st.st_mode))
+	{
+	  free (p);
+	  continue;
+	}
+
+      physical_paths[num_path++] = p;
+      if (num_path > max_physical_path)
+	break;
+    }
+
+  if (num_path > 1)
+    qsort (physical_paths, num_path, sizeof (physical_paths[0]), grub_qsort_strcmp);
+
+  for (ret = NULL, i = 0; i < num_path; i++)
+    {
+      char *p = get_ofpathname (physical_paths[i]);
+
+      if (p == NULL || *p == '\0')
+	continue;
+
+      if (ret != NULL)
+	{
+	  char *t = ret;
+	  ret = xasprintf ("%s %s", ret, p);
+	  free (t);
+	  free (p);
+	}
+      else
+	ret = p;
+    }
+
+ out:
+  for (i = 0; i < num_path; i++)
+    free (physical_paths[i]);
+  if (dp != NULL)
+    closedir (dp);
+  free (sysfs_slaves);
+  if (fp != NULL)
+    fclose (fp);
+  free (sysfs_uuid);
+  free (sysfs_path);
+  free (device);
+  free (devdir);
+  return ret;
+}
+
 void
 grub_install_register_ieee1275 (int is_prep, const char *install_device,
 				int partno, const char *relpath)
@@ -355,6 +461,15 @@ grub_install_register_ieee1275 (int is_prep, const char *install_device,
           free (boot_device);
           boot_device = add_multiple_nvme_bootdevices (install_device);
         }
+      else
+	{
+	  char *mpath_devices = add_multiple_dm_multipath_bootdevices (install_device);
+	  if (mpath_devices != NULL)
+	    {
+	      free (boot_device);
+	      boot_device = mpath_devices;
+	    }
+	}
     }
 
   if (grub_util_exec ((const char * []){ "nvsetenv", "boot-device",
-- 
2.53.0