debian/patches/ignore_checksum_seed_incompat_feature.patch

   1 commit 7fd5feff97c4b1f446f8fcf6d37aca0c64e7c763
   2 Author: Javier Martinez Canillas <javierm@redhat.com>
   3 Date:   Fri Jun 11 21:36:16 2021 +0200
   4
   5     fs/ext2: Ignore checksum seed incompat feature
   6
   7     This incompat feature is used to denote that the filesystem stored its
   8     metadata checksum seed in the superblock. This is used to allow tune2fs
   9     changing the UUID on a mounted metdata_csum filesystem without having
  10     to rewrite all the disk metadata. However, the GRUB doesn't use the
  11     metadata checksum at all. So, it can just ignore this feature if it
  12     is enabled. This is consistent with the GRUB filesystem code in general
  13     which just does a best effort to access the filesystem's data.
  14
  15     The checksum seed incompat feature has to be removed from the ignore
  16     list if the support for metadata checksum verification is added to the
  17     GRUB ext2 driver later.
  18
  19     Suggested-by: Eric Sandeen <esandeen@redhat.com>
  20     Suggested-by: Lukas Czerner <lczerner@redhat.com>
  21     Signed-off-by: Javier Martinez Canillas <javierm@redhat.com>
  22     Reviewed-by: Lukas Czerner <lczerner@redhat.com>
  23     Reviewed-by: Daniel Kiper <daniel.kiper@oracle.com>
  24
  25 diff --git a/grub-core/fs/ext2.c b/grub-core/fs/ext2.c
  26 index e7dd78e66..4953a1591 100644
  27 --- a/grub-core/fs/ext2.c
  28 +++ b/grub-core/fs/ext2.c
  29 @@ -103,6 +103,7 @@ GRUB_MOD_LICENSE ("GPLv3+");
  30  #define EXT4_FEATURE_INCOMPAT_64BIT            0x0080
  31  #define EXT4_FEATURE_INCOMPAT_MMP              0x0100
  32  #define EXT4_FEATURE_INCOMPAT_FLEX_BG          0x0200
  33 +#define EXT4_FEATURE_INCOMPAT_CSUM_SEED                0x2000
  34  #define EXT4_FEATURE_INCOMPAT_ENCRYPT          0x10000
  35
  36  /* The set of back-incompatible features this driver DOES support. Add (OR)
  37 @@ -123,10 +124,15 @@ GRUB_MOD_LICENSE ("GPLv3+");
  38   * mmp:            Not really back-incompatible - was added as such to
  39   *                 avoid multiple read-write mounts. Safe to ignore for this
  40   *                 RO driver.
  41 + * checksum seed:  Not really back-incompatible - was added to allow tools
  42 + *                 such as tune2fs to change the UUID on a mounted metadata
  43 + *                 checksummed filesystem. Safe to ignore for now since the
  44 + *                 driver doesn't support checksum verification. However, it
  45 + *                 has to be removed from this list if the support is added later.
  46   */
  47  #define EXT2_DRIVER_IGNORED_INCOMPAT ( EXT3_FEATURE_INCOMPAT_RECOVER \
  48 -                                    | EXT4_FEATURE_INCOMPAT_MMP)
  49 -
  50 +                                    | EXT4_FEATURE_INCOMPAT_MMP \
  51 +                                    | EXT4_FEATURE_INCOMPAT_CSUM_SEED)
  52
  53  #define EXT3_JOURNAL_MAGIC_NUMBER      0xc03b3998U
  54