From 7fd5feff97c4b1f446f8fcf6d37aca0c64e7c763 Mon Sep 17 00:00:00 2001 From: Javier Martinez Canillas Date: Fri, 11 Jun 2021 21:36:16 +0200 Subject: [PATCH] fs/ext2: Ignore checksum seed incompat feature This incompat feature is used to denote that the filesystem stored its metadata checksum seed in the superblock. This is used to allow tune2fs changing the UUID on a mounted metdata_csum filesystem without having to rewrite all the disk metadata. However, the GRUB doesn't use the metadata checksum at all. So, it can just ignore this feature if it is enabled. This is consistent with the GRUB filesystem code in general which just does a best effort to access the filesystem's data. The checksum seed incompat feature has to be removed from the ignore list if the support for metadata checksum verification is added to the GRUB ext2 driver later. Suggested-by: Eric Sandeen Suggested-by: Lukas Czerner Signed-off-by: Javier Martinez Canillas Reviewed-by: Lukas Czerner Reviewed-by: Daniel Kiper --- grub-core/fs/ext2.c | 10 ++++++++-- 1 file changed, 8 insertions(+), 2 deletions(-) diff --git a/grub-core/fs/ext2.c b/grub-core/fs/ext2.c index e7dd78e66..4953a1591 100644 --- a/grub-core/fs/ext2.c +++ b/grub-core/fs/ext2.c @@ -103,6 +103,7 @@ GRUB_MOD_LICENSE ("GPLv3+"); #define EXT4_FEATURE_INCOMPAT_64BIT 0x0080 #define EXT4_FEATURE_INCOMPAT_MMP 0x0100 #define EXT4_FEATURE_INCOMPAT_FLEX_BG 0x0200 +#define EXT4_FEATURE_INCOMPAT_CSUM_SEED 0x2000 #define EXT4_FEATURE_INCOMPAT_ENCRYPT 0x10000 /* The set of back-incompatible features this driver DOES support. Add (OR) @@ -123,10 +124,15 @@ GRUB_MOD_LICENSE ("GPLv3+"); * mmp: Not really back-incompatible - was added as such to * avoid multiple read-write mounts. Safe to ignore for this * RO driver. + * checksum seed: Not really back-incompatible - was added to allow tools + * such as tune2fs to change the UUID on a mounted metadata + * checksummed filesystem. Safe to ignore for now since the + * driver doesn't support checksum verification. However, it + * has to be removed from this list if the support is added later. */ #define EXT2_DRIVER_IGNORED_INCOMPAT ( EXT3_FEATURE_INCOMPAT_RECOVER \ - | EXT4_FEATURE_INCOMPAT_MMP) - + | EXT4_FEATURE_INCOMPAT_MMP \ + | EXT4_FEATURE_INCOMPAT_CSUM_SEED) #define EXT3_JOURNAL_MAGIC_NUMBER 0xc03b3998U -- 2.34.1