From f01314a822dbe9ad39b2f7d0f3717ef6e4c24f4a Mon Sep 17 00:00:00 2001
From: Michael Chang <[email protected]>
Date: Fri, 15 Apr 2022 21:45:04 +0800
Subject: [PATCH 2/2] Mark environmet blocks as used for image embedding.

Now that grub will attempt to use full btrfs bootloader area, the
embedded image could have overlapped with environment blocks if it's
size grows too much. Let's define a dedicated area for environment
blocks to the used block mappings for the embedding process so it can be
skipped.

Signed-off-by: Michael Chang <[email protected]>
---
 grub-core/fs/btrfs.c | 3 ++-
 include/grub/fs.h    | 2 ++
 util/grub-editenv.c  | 2 +-
 3 files changed, 5 insertions(+), 2 deletions(-)

--- a/grub-core/fs/btrfs.c
+++ b/grub-core/fs/btrfs.c
@@ -2637,7 +2637,7 @@
 
 static const struct {
   struct embed_region available;
-  struct embed_region used[6];
+  struct embed_region used[7];
 } btrfs_head = {
   .available = {0, GRUB_DISK_KiB_TO_SECTORS (1024)}, /* The first 1 MiB. */
   .used = {
@@ -2645,6 +2645,7 @@
     {GRUB_DISK_KiB_TO_SECTORS (64) - 1, 1},                        /* Overflow guard. */
     {GRUB_DISK_KiB_TO_SECTORS (64), GRUB_DISK_KiB_TO_SECTORS (4)}, /* 4 KiB superblock. */
     {GRUB_DISK_KiB_TO_SECTORS (68), 1},                            /* Overflow guard. */
+    {GRUB_DISK_KiB_TO_SECTORS (ENV_BTRFS_OFFSET) - 1, 3},          /* Environment Block. */
     {GRUB_DISK_KiB_TO_SECTORS (1024) - 1, 1},                      /* Overflow guard. */
     {0, 0}                                                         /* Array terminator. */
   }
--- a/include/grub/fs.h
+++ b/include/grub/fs.h
@@ -128,4 +128,6 @@
 
 grub_fs_t EXPORT_FUNC(grub_fs_probe) (grub_device_t device);
 
+#define ENV_BTRFS_OFFSET (256)
+
 #endif /* ! GRUB_FS_HEADER */
--- a/util/grub-editenv.c
+++ b/util/grub-editenv.c
@@ -128,7 +128,7 @@
   int offset;
   int size;
 } fs_envblk_spec[] = {
-  { "btrfs", 256 * 1024, GRUB_DISK_SECTOR_SIZE },
+  { "btrfs", ENV_BTRFS_OFFSET * 1024, GRUB_DISK_SECTOR_SIZE },
   { NULL, 0, 0 }
 };