From: Colin Watson <cjwatson@ubuntu.com>
Subject: Improve devmapper support
Date: 2011-05-18 07:35:47 +0000

=== modified file 'grub-core/kern/emu/getroot.c'
--- a/grub-core/kern/emu/getroot.c	2011-04-21 09:26:29 +0000
+++ b/grub-core/kern/emu/getroot.c	2011-05-18 07:35:47 +0000
@@ -34,6 +34,10 @@
 #include <stdint.h>
 #include <grub/util/misc.h>
 
+#ifdef HAVE_DEVICE_MAPPER
+# include <libdevmapper.h>
+#endif
+
 #ifdef __GNU__
 #include <hurd.h>
 #include <hurd/lookup.h>
@@ -634,32 +638,65 @@
 }
 
 static int
-grub_util_is_dmraid (const char *os_dev)
+grub_util_is_lvm (const char *os_dev)
 {
-  if (! strncmp (os_dev, "/dev/mapper/nvidia_", 19))
-    return 1;
-  else if (! strncmp (os_dev, "/dev/mapper/isw_", 16))
-    return 1;
-  else if (! strncmp (os_dev, "/dev/mapper/hpt37x_", 19))
-    return 1;
-  else if (! strncmp (os_dev, "/dev/mapper/hpt45x_", 19))
-    return 1;
-  else if (! strncmp (os_dev, "/dev/mapper/via_", 16))
-    return 1;
-  else if (! strncmp (os_dev, "/dev/mapper/lsi_", 16))
-    return 1;
-  else if (! strncmp (os_dev, "/dev/mapper/pdc_", 16))
-    return 1;
-  else if (! strncmp (os_dev, "/dev/mapper/jmicron_", 20))
-    return 1;
-  else if (! strncmp (os_dev, "/dev/mapper/asr_", 16))
-    return 1;
-  else if (! strncmp (os_dev, "/dev/mapper/sil_", 16))
-    return 1;
-  else if (! strncmp (os_dev, "/dev/mapper/ddf1_", 17))
-    return 1;
-
-  return 0;
+  if ((strncmp ("/dev/mapper/", os_dev, 12) != 0))
+    return 0;
+  
+#ifdef HAVE_DEVICE_MAPPER
+  {
+    struct dm_tree *tree;
+    uint32_t maj, min;
+    struct dm_tree_node *node = NULL;
+    const char *node_uuid;
+    struct stat st;
+
+    if (stat (os_dev, &st) < 0)
+      return 0;
+
+    tree = dm_tree_create ();
+    if (! tree)
+      {
+	grub_printf ("Failed to create tree\n");
+	grub_dprintf ("hostdisk", "dm_tree_create failed\n");
+	return 0;
+      }
+
+    maj = major (st.st_rdev);
+    min = minor (st.st_rdev);
+
+    if (! dm_tree_add_dev (tree, maj, min))
+      {
+	grub_dprintf ("hostdisk", "dm_tree_add_dev failed\n");
+	dm_tree_free (tree);
+	return 0;
+      }
+
+    node = dm_tree_find_node (tree, maj, min);
+    if (! node)
+      {
+	grub_dprintf ("hostdisk", "dm_tree_find_node failed\n");
+	dm_tree_free (tree);
+	return 0;
+      }
+    node_uuid = dm_tree_node_get_uuid (node);
+    if (! node_uuid)
+      {
+	grub_dprintf ("hostdisk", "%s has no DM uuid\n", os_dev);
+	dm_tree_free (tree);
+	return 0;
+      }
+    if (strncmp (node_uuid, "LVM-", 4) != 0)
+      {
+	dm_tree_free (tree);
+	return 0;
+      }
+    dm_tree_free (tree);
+    return 1;
+  }
+#else
+  return 1;
+#endif /* HAVE_DEVICE_MAPPER */
 }
 
 int
@@ -671,13 +708,11 @@
     return GRUB_DEV_ABSTRACTION_NONE;
 
   /* Check for LVM.  */
-  if (!strncmp (os_dev, "/dev/mapper/", 12)
-      && ! grub_util_is_dmraid (os_dev)
-      && strncmp (os_dev, "/dev/mapper/mpath", 17) != 0)
+  if (grub_util_is_lvm (os_dev))
     return GRUB_DEV_ABSTRACTION_LVM;
 
   /* Check for RAID.  */
-  if (!strncmp (os_dev, "/dev/md", 7))
+  if (!strncmp (os_dev, "/dev/md", 7) && ! grub_util_device_is_mapped (os_dev))
     return GRUB_DEV_ABSTRACTION_RAID;
 #endif
 

=== modified file 'grub-core/kern/emu/hostdisk.c'
--- a/grub-core/kern/emu/hostdisk.c	2011-05-09 16:59:35 +0000
+++ b/grub-core/kern/emu/hostdisk.c	2011-05-18 07:35:47 +0000
@@ -24,6 +24,7 @@
 #include <grub/err.h>
 #include <grub/emu/misc.h>
 #include <grub/emu/hostdisk.h>
+#include <grub/emu/getroot.h>
 #include <grub/misc.h>
 #include <grub/i18n.h>
 #include <grub/list.h>
@@ -331,18 +332,23 @@
   return GRUB_ERR_NONE;
 }
 
+int
+grub_util_device_is_mapped (const char *dev)
+{
 #ifdef HAVE_DEVICE_MAPPER
-static int
-device_is_mapped (const char *dev)
-{
   struct stat st;
 
+  if (!grub_device_mapper_supported ())
+    return 0;
+
   if (stat (dev, &st) < 0)
     return 0;
 
   return dm_is_dm_major (major (st.st_rdev));
+#else
+  return 0;
+#endif /* HAVE_DEVICE_MAPPER */
 }
-#endif /* HAVE_DEVICE_MAPPER */
 
 #if defined (__FreeBSD__) || defined(__FreeBSD_kernel__)
 /* FIXME: geom actually gives us the whole container hierarchy.
@@ -418,7 +424,7 @@
 # endif /* !defined(HAVE_DIOCGDINFO) */
 
 # ifdef HAVE_DEVICE_MAPPER
-  if (grub_device_mapper_supported () && device_is_mapped (dev)) {
+  if (grub_util_device_is_mapped (dev)) {
     struct dm_task *task = NULL;
     grub_uint64_t start, length;
     char *target_type, *params, *space;
@@ -1149,6 +1155,54 @@
   return ret;
 }
 
+#ifdef HAVE_DEVICE_MAPPER
+static int
+grub_util_get_dm_node_linear_info (const char *dev,
+				   int *maj, int *min)
+{
+  struct dm_task *dmt;
+  void *next = NULL;
+  uint64_t length, start;
+  char *target, *params;
+  char *ptr;
+  int major, minor;
+
+  dmt = dm_task_create(DM_DEVICE_TABLE);
+  if (!dmt)
+    return 0;
+  
+  if (!dm_task_set_name(dmt, dev))
+    return 0;
+  dm_task_no_open_count(dmt);
+  if (!dm_task_run(dmt))
+    return 0;
+  next = dm_get_next_target(dmt, next, &start, &length,
+			    &target, &params);
+  if (grub_strcmp (target, "linear") != 0)
+    return 0;
+  major = grub_strtoul (params, &ptr, 10);
+  if (grub_errno)
+    {
+      grub_errno = GRUB_ERR_NONE;
+      return 0;
+    }
+  if (*ptr != ':')
+    return 0;
+  ptr++;
+  minor = grub_strtoul (ptr, 0, 10);
+  if (grub_errno)
+    {
+      grub_errno = GRUB_ERR_NONE;
+      return 0;
+    }
+  if (maj)
+    *maj = major;
+  if (min)
+    *min = minor;
+  return 1;
+}
+#endif
+
 static char *
 convert_system_partition_to_system_disk (const char *os_dev, struct stat *st)
 {
@@ -1325,9 +1379,39 @@
 	      node = NULL;
 	      goto devmapper_out;
 	    }
-	  else if (strncmp (node_uuid, "DMRAID-", 7) != 0)
-	    {
+	  if (strncmp (node_uuid, "LVM-", 4) == 0)
+	    {
+	      grub_dprintf ("hostdisk", "%s is an LVM\n", path);
+	      node = NULL;
+	      goto devmapper_out;
+	    }
+	  if (strncmp (node_uuid, "mpath-", 6) == 0)
+	    {
+	      /* Multipath partitions have partN-mpath-* UUIDs, and are
+		 linear mappings so are handled by
+		 grub_util_get_dm_node_linear_info.  Multipath disks are not
+		 linear mappings and must be handled specially.  */
+	      grub_dprintf ("hostdisk", "%s is a multipath disk\n", path);
+	      mapper_name = dm_tree_node_get_name (node);
+	      goto devmapper_out;
+	    }
+	  if (strncmp (node_uuid, "DMRAID-", 7) != 0)
+	    {
+	      int major, minor;
+	      const char *node_name;
 	      grub_dprintf ("hostdisk", "%s is not DM-RAID\n", path);
+
+	      if ((node_name = dm_tree_node_get_name (node))
+		  && grub_util_get_dm_node_linear_info (node_name,
+							&major, &minor))
+		{
+		  if (tree)
+		    dm_tree_free (tree);
+		  free (path);
+		  char *ret = grub_find_device (NULL, (major << 8) | minor);
+		  return ret;
+		}
+
 	      node = NULL;
 	      goto devmapper_out;
 	    }

=== modified file 'include/grub/emu/misc.h'
--- a/include/grub/emu/misc.h	2010-12-02 13:26:46 +0000
+++ b/include/grub/emu/misc.h	2011-05-18 07:35:47 +0000
@@ -54,6 +54,8 @@
 
 char *grub_make_system_path_relative_to_its_root (const char *path)
   __attribute__ ((warn_unused_result));
+int
+grub_util_device_is_mapped (const char *dev);
 
 void * EXPORT_FUNC(xmalloc) (grub_size_t size) __attribute__ ((warn_unused_result));
 void * EXPORT_FUNC(xrealloc) (void *ptr, grub_size_t size) __attribute__ ((warn_unused_result));