lvm-support-2.06.patch

From: Alexander Rumyantsev <github.com@rumyantsev.com>
Date: Mon Jul 13 14:34:12 UTC 2015
Subject: [PATCH] Install to LVM PVs

Original patch made by Gabriel de Perthuis <g2p.code@gmail.com>
http://lists.gnu.org/archive/html/grub-devel/2013-09/msg00113.html

This patch lets grub install to a reserved area in LVM physical volumes.
These bootloader areas can be created with LVM 2.02.99 and the --bootloaderareasize argument to pvcreate and vgconvert.
Tested it in QEMU and VMware, installing to and booting a disk that contains a PV and no partition table.

Adopted for RHEL-based distros by Alexander Rumyantsev <github.com@rumyantsev.com>
Just add this file to patches list in RPM spec file and rebuild the package

diff -Naur grub-2.06.orig/grub-core/disk/lvm.c grub-2.06/grub-core/disk/lvm.c
--- grub-2.06.orig/grub-core/disk/lvm.c	2023-03-05 13:14:42.558637854 +0300
+++ grub-2.06/grub-core/disk/lvm.c	2023-03-05 13:15:09.890765170 +0300
@@ -132,6 +132,38 @@
     }
 }
 
+static struct grub_lvm_pv_header *
+grub_lvm_get_pvh(grub_disk_t disk, char buf[static GRUB_LVM_LABEL_SIZE])
+{
+  struct grub_lvm_label_header *lh = (struct grub_lvm_label_header *) buf;
+  unsigned int i;
+
+  /* Search for label. */
+  for (i = 0; i < GRUB_LVM_LABEL_SCAN_SECTORS; i++)
+    {
+      if (grub_disk_read (disk, i, 0, GRUB_LVM_LABEL_SIZE, buf))
+       return NULL;
+
+      if ((! grub_strncmp ((char *)lh->id, GRUB_LVM_LABEL_ID,
+                          sizeof (lh->id)))
+         && (! grub_strncmp ((char *)lh->type, GRUB_LVM_LVM2_LABEL,
+                             sizeof (lh->type))))
+       break;
+    }
+
+  /* Return if we didn't find a label. */
+  if (i == GRUB_LVM_LABEL_SCAN_SECTORS)
+    {
+#ifdef GRUB_UTIL
+      grub_util_info ("no LVM signature found");
+#endif
+      return NULL;
+    }
+
+  return (struct grub_lvm_pv_header *) (buf + grub_le_to_cpu32(lh->offset_xl));
+}
+
+
 static struct grub_diskfilter_vg * 
 grub_lvm_detect (grub_disk_t disk,
 		 struct grub_diskfilter_pv_id *id,
@@ -145,7 +177,6 @@
   char pv_id[GRUB_LVM_ID_STRLEN+1];
   char *metadatabuf, *mda_end, *vgname;
   const char *p, *q;
-  struct grub_lvm_label_header *lh = (struct grub_lvm_label_header *) buf;
   struct grub_lvm_pv_header *pvh;
   struct grub_lvm_disk_locn *dlocn;
   struct grub_lvm_mda_header *mdah;
@@ -155,44 +186,9 @@
   struct grub_diskfilter_vg *vg;
   struct grub_diskfilter_pv *pv;
 
-  /* Search for label. */
-  for (i = 0; i < GRUB_LVM_LABEL_SCAN_SECTORS; i++)
-    {
-      err = grub_disk_read (disk, i, 0, sizeof(buf), buf);
-      if (err)
-	goto fail;
-
-      if ((! grub_strncmp ((char *)lh->id, GRUB_LVM_LABEL_ID,
-			   sizeof (lh->id)))
-	  && (! grub_strncmp ((char *)lh->type, GRUB_LVM_LVM2_LABEL,
-			      sizeof (lh->type))))
-	break;
-    }
-
-  /* Return if we didn't find a label. */
-  if (i == GRUB_LVM_LABEL_SCAN_SECTORS)
-    {
-#ifdef GRUB_UTIL
-      grub_util_info ("no LVM signature found");
-#endif
-      goto fail;
-    }
-
-  /*
-   * We read a grub_lvm_pv_header and then 2 grub_lvm_disk_locns that
-   * immediately follow the PV header. Make sure we have space for both.
-   */
-  if (grub_le_to_cpu32 (lh->offset_xl) >=
-      GRUB_LVM_LABEL_SIZE - sizeof (struct grub_lvm_pv_header) -
-      2 * sizeof (struct grub_lvm_disk_locn))
-    {
-#ifdef GRUB_UTIL
-      grub_util_info ("LVM PV header/disk locations are beyond the end of the block");
-#endif
-      goto fail;
-    }
-
-  pvh = (struct grub_lvm_pv_header *) (buf + grub_le_to_cpu32(lh->offset_xl));
+  pvh = grub_lvm_get_pvh(disk, buf);
+  if (! pvh)
+    goto fail;
 
   for (i = 0, j = 0; i < GRUB_LVM_ID_LEN; i++)
     {
@@ -205,7 +201,7 @@
   dlocn = pvh->disk_areas_xl;
 
   dlocn++;
-  /* Is it possible to have multiple data/metadata areas? I haven't
+  /* Is it possible to have multiple data areas? I haven't
      seen devices that have it. */
   if (dlocn->offset)
     {
@@ -1072,6 +1068,89 @@
   return NULL;
 }
 
+#ifdef GRUB_UTIL
+int
+grub_util_is_lvm(grub_disk_t disk)
+{
+  struct grub_diskfilter_pv_id id;
+  struct grub_diskfilter_vg *vg;
+  grub_disk_addr_t start_sector;
+  vg = grub_lvm_detect(disk, &id, &start_sector);
+  if (! vg)
+    return 0;
+  /* don't free the vg, it's held by grub_diskfilter_vg_register */
+  grub_free(id.uuid);
+  return 1;
+}
+
+grub_err_t
+grub_util_lvm_embed (struct grub_disk *disk, unsigned int *nsectors,
+                    unsigned int max_nsectors,
+                    grub_embed_type_t embed_type,
+                    grub_disk_addr_t **sectors)
+{
+  char buf[GRUB_LVM_LABEL_SIZE];
+  struct grub_lvm_pv_header *pvh;
+  struct grub_lvm_pv_header_ext *pvh_ext;
+  struct grub_diskfilter_pv *pv = NULL;
+  struct grub_diskfilter_vg *vg = NULL;
+  struct grub_lvm_disk_locn *dlocn;
+  grub_uint64_t ba_offset, ba_size, ba_start_sector;
+  unsigned int i;
+
+  if (embed_type != GRUB_EMBED_PCBIOS)
+    return grub_error (GRUB_ERR_NOT_IMPLEMENTED_YET,
+                      "LVM curently supports only PC-BIOS embedding");
+  if (disk->partition)
+    return grub_error (GRUB_ERR_BUG, "disk isn't LVM");
+  pv = grub_diskfilter_get_pv_from_disk (disk, &vg);
+  if (! pv)
+    return grub_error (GRUB_ERR_BUG, "disk isn't LVM");
+
+  pvh = grub_lvm_get_pvh(disk, buf);
+  if (! pvh)
+    return grub_error (GRUB_ERR_BUG, "disk isn't LVM");
+
+  dlocn = pvh->disk_areas_xl;
+
+  /* skip past the data area list */
+  while (dlocn->offset)
+    dlocn++;
+  dlocn++;
+  /* and the metadata area list */
+  while (dlocn->offset)
+    dlocn++;
+  dlocn++;
+
+  pvh_ext = (struct grub_lvm_pv_header_ext*)dlocn;
+  if (! pvh_ext->version_xl)
+    return grub_error (GRUB_ERR_BUG, "LVM PV doesn't have a bootloader area");
+
+  dlocn = pvh_ext->disk_areas_xl;
+  ba_offset = grub_le_to_cpu64 (dlocn->offset);
+  ba_size = grub_le_to_cpu64 (dlocn->size);
+  if (! (ba_offset && ba_size))
+    return grub_error (GRUB_ERR_BUG, "LVM PV doesn't have a bootloader area");
+  /* could be worked around with extra arithmetic if this actually happens */
+  if (ba_offset % GRUB_DISK_SECTOR_SIZE)
+    return grub_error (
+      GRUB_ERR_BUG, "LVM bootloader area is improperly aligned");
+  ba_start_sector = ba_offset / GRUB_DISK_SECTOR_SIZE;
+
+  *nsectors = ba_size / GRUB_DISK_SECTOR_SIZE;
+  if (*nsectors > max_nsectors)
+    *nsectors = max_nsectors;
+
+  *sectors = grub_malloc (*nsectors * sizeof (**sectors));
+  if (!*sectors)
+    return grub_errno;
+  for (i = 0; i < *nsectors; i++)
+    (*sectors)[i] = ba_start_sector + i;
+
+  return GRUB_ERR_NONE;
+}
+#endif
+
 
 
 static struct grub_diskfilter grub_lvm_dev = {
diff -Naur grub-2.06.orig/include/grub/diskfilter.h grub-2.06/include/grub/diskfilter.h
--- grub-2.06.orig/include/grub/diskfilter.h	2023-03-05 13:14:42.635638213 +0300
+++ grub-2.06/include/grub/diskfilter.h	2023-03-05 13:15:09.891765175 +0300
@@ -75,6 +75,9 @@
 #ifdef GRUB_UTIL
   char **partmaps;
 #endif
+  /* Optional bootloader embedding area */
+  grub_uint64_t ba_offset;
+  grub_uint64_t ba_size;
 };
 
 struct grub_diskfilter_lv {
diff -Naur grub-2.06.orig/include/grub/emu/hostdisk.h grub-2.06/include/grub/emu/hostdisk.h
--- grub-2.06.orig/include/grub/emu/hostdisk.h	2023-03-05 13:14:42.625638166 +0300
+++ grub-2.06/include/grub/emu/hostdisk.h	2023-03-05 13:15:09.891765175 +0300
@@ -45,9 +45,16 @@
 char *
 grub_util_get_ldm (grub_disk_t disk, grub_disk_addr_t start);
 int
+grub_util_is_lvm (grub_disk_t disk);
+int
 grub_util_is_ldm (grub_disk_t disk);
 #ifdef GRUB_UTIL
 grub_err_t
+grub_util_lvm_embed (struct grub_disk *disk, unsigned int *nsectors,
+                    unsigned int max_nsectors,
+                    grub_embed_type_t embed_type,
+                    grub_disk_addr_t **sectors);
+grub_err_t
 grub_util_ldm_embed (struct grub_disk *disk, unsigned int *nsectors,
 		     unsigned int max_nsectors,
 		     grub_embed_type_t embed_type,
diff -Naur grub-2.06.orig/include/grub/lvm.h grub-2.06/include/grub/lvm.h
--- grub-2.06.orig/include/grub/lvm.h	2023-03-05 13:14:42.638638227 +0300
+++ grub-2.06/include/grub/lvm.h	2023-03-05 13:15:09.891765175 +0300
@@ -62,6 +62,13 @@
   struct grub_lvm_disk_locn disk_areas_xl[0];	/* Two lists */
 } GRUB_PACKED;
 
+struct grub_lvm_pv_header_ext {
+  grub_uint32_t version_xl;
+  grub_uint32_t flags_xl;
+  /* NULL-terminated list of bootloader embedding areas */
+  struct grub_lvm_disk_locn disk_areas_xl[0];
+} __attribute__ ((packed));
+
 #define GRUB_LVM_FMTT_MAGIC "\040\114\126\115\062\040\170\133\065\101\045\162\060\116\052\076"
 #define GRUB_LVM_FMTT_VERSION 1
 #define GRUB_LVM_MDA_HEADER_SIZE 512
diff -Naur grub-2.06.orig/util/setup.c grub-2.06/util/setup.c
--- grub-2.06.orig/util/setup.c	2023-03-05 13:14:42.674638394 +0300
+++ grub-2.06/util/setup.c	2023-03-05 13:13:28.372292303 +0300
@@ -403,7 +403,7 @@
       .container = dest_dev->disk->partition,
       .multiple_partmaps = 0
     };
-    int is_ldm;
+    int is_ldm, is_lvm;
     grub_err_t err;
     grub_disk_addr_t *sectors;
     unsigned int i;
@@ -412,6 +412,7 @@
 
     grub_partition_iterate (dest_dev->disk, identify_partmap, &ctx);
 
+#ifndef GRUB_SETUP_SPARC64
 #ifdef GRUB_SETUP_BIOS
     /* Copy the partition table.  */
     if (ctx.dest_partmap ||
@@ -422,6 +423,7 @@
 
     free (tmp_img);
 #endif
+#endif
 
     if (ctx.container
 	&& grub_strcmp (ctx.container->partmap->name, "msdos") == 0
@@ -438,8 +440,9 @@
       grub_errno = GRUB_ERR_NONE;
 
     is_ldm = grub_util_is_ldm (dest_dev->disk);
+    is_lvm = grub_util_is_lvm (dest_dev->disk);
 
-    if (fs_probe)
+    if (!is_lvm && fs_probe)
       {
 	if (!fs && !ctx.dest_partmap)
 	  grub_util_error (_("unable to identify a filesystem in %s; safety check can't be performed"),
@@ -477,7 +480,7 @@
 
       }
 
-    if (! ctx.dest_partmap && ! fs && !is_ldm)
+    if (! ctx.dest_partmap && ! fs && !is_ldm && !is_lvm)
       {
 	grub_util_warn ("%s", _("Attempting to install GRUB to a partitionless disk or to a partition.  This is a BAD idea."));
 	goto unable_to_embed;
@@ -526,7 +529,28 @@
     maxsec += 2;
 #endif
 
-    if (is_ldm)
+    if (is_lvm) {
+      err = grub_util_lvm_embed (dest_dev->disk, &nsec, maxsec,
+                                 GRUB_EMBED_PCBIOS, &sectors);
+
+#ifdef GRUB_SETUP_BIOS
+      /* DIRTY HACK: Do not allow blkid to determine msdos partition type */
+
+      /* clear partition table */
+      memset (boot_img + GRUB_BOOT_MACHINE_WINDOWS_NT_MAGIC,
+              0, GRUB_BOOT_MACHINE_PART_END - GRUB_BOOT_MACHINE_WINDOWS_NT_MAGIC);
+
+      /* first partition boot flag: invalid partition */
+      ((struct grub_msdos_partition_entry *)
+        (boot_img + GRUB_BOOT_MACHINE_PART_START))->flag = 0x01;
+
+      /* first partition type: GPT */
+      ((struct grub_msdos_partition_entry *)
+        (boot_img + GRUB_BOOT_MACHINE_PART_START))->type = GRUB_PC_PARTITION_TYPE_GPT_DISK;
+#endif
+
+    }
+    else if (is_ldm)
       err = grub_util_ldm_embed (dest_dev->disk, &nsec, maxsec,
 				 GRUB_EMBED_PCBIOS, &sectors);
     else if (ctx.dest_partmap)