[Buildroot] [git commit] boot/grub2: fix incompat e2fsprogs feature use
Peter Korsgaard
peter at korsgaard.com
Sat Sep 30 09:59:31 UTC 2023
commit: https://git.buildroot.net/buildroot/commit/?id=9c25f1b51eeb988449ad0f1f524283ef5361ee4d
branch: https://git.buildroot.net/buildroot/commit/?id=refs/heads/master
With bump of package/e2fsprogs to 1.47.0 [1] a freshly generated
ext4 fs has unfortunately different default features enabled
(e.g. metadata_csum_seed). This and some other newer fs features
(e.g. large_dir) are however not supported by our grub2.
Thus, newly generated ext-based rootfs won't be recognized by grub2
and are therefore not bootable/usable from grub2 anymore. This is
an issue already known to other Linux derivates [2],[3],[4].
This commit introduces two additional upstream patches to
package/grub2 which adds EXT4_FEATURE_INCOMPAT_CSUM_SEED and
EXT4_FEATURE_INCOMPAT_LARGEDIR to the EXT2_DRIVER_IGNORED_INCOMPAT
list of ignored incompatible ext features, allowing grub2 to
use ext filesystems with these newer default feature sets.
[1] https://git.buildroot.net/buildroot/commit/?id=6a21733f839478d902f3eab287a82b456e55f708
[2] https://bugs.launchpad.net/ubuntu/+source/grub2/+bug/1844012
[3] https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=1031325
[4] https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=1030939
Signed-off-by: Jens Maus <mail at jens-maus.de>
Signed-off-by: Peter Korsgaard <peter at korsgaard.com>
---
...xt2-Ignore-checksum-seed-incompat-feature.patch | 61 ++++++++++++++++++++++
...xt2-Ignore-the-large_dir-incompat-feature.patch | 60 +++++++++++++++++++++
2 files changed, 121 insertions(+)
diff --git a/boot/grub2/0019-fs-ext2-Ignore-checksum-seed-incompat-feature.patch b/boot/grub2/0019-fs-ext2-Ignore-checksum-seed-incompat-feature.patch
new file mode 100644
index 0000000000..9a913e2279
--- /dev/null
+++ b/boot/grub2/0019-fs-ext2-Ignore-checksum-seed-incompat-feature.patch
@@ -0,0 +1,61 @@
+From 7fd5feff97c4b1f446f8fcf6d37aca0c64e7c763 Mon Sep 17 00:00:00 2001
+From: Javier Martinez Canillas <javierm at redhat.com>
+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 <esandeen at redhat.com>
+Suggested-by: Lukas Czerner <lczerner at redhat.com>
+Signed-off-by: Javier Martinez Canillas <javierm at redhat.com>
+Reviewed-by: Lukas Czerner <lczerner at redhat.com>
+Reviewed-by: Daniel Kiper <daniel.kiper at oracle.com>
+Upstream: 7fd5feff97c4b1f446f8fcf6d37aca0c64e7c763
+Signed-off-by: Jens Maus <mail at jens-maus.de>
+---
+ 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
+
diff --git a/boot/grub2/0020-fs-ext2-Ignore-the-large_dir-incompat-feature.patch b/boot/grub2/0020-fs-ext2-Ignore-the-large_dir-incompat-feature.patch
new file mode 100644
index 0000000000..43b182f968
--- /dev/null
+++ b/boot/grub2/0020-fs-ext2-Ignore-the-large_dir-incompat-feature.patch
@@ -0,0 +1,60 @@
+From 2e9fa73a040462b81bfbfe56c0bc7ad2d30b446b Mon Sep 17 00:00:00 2001
+From: Theodore Ts'o <tytso at mit.edu>
+Date: Tue, 30 Aug 2022 22:41:59 -0400
+Subject: [PATCH] fs/ext2: Ignore the large_dir incompat feature
+
+Recently, ext4 added the large_dir feature, which adds support for
+a 3 level htree directory support.
+
+The GRUB supports existing file systems with htree directories by
+ignoring their existence, and since the index nodes for the hash tree
+look like deleted directory entries (by design), the GRUB can simply do
+a brute force O(n) linear search of directories. The same is true for
+3 level deep htrees indicated by large_dir feature flag.
+
+Hence, it is safe for the GRUB to ignore the large_dir incompat feature.
+
+Fixes: https://savannah.gnu.org/bugs/?61606
+
+Signed-off-by: Theodore Ts'o <tytso at mit.edu>
+Reviewed-by: Daniel Kiper <daniel.kiper at oracle.com>
+Upstream: 2e9fa73a040462b81bfbfe56c0bc7ad2d30b446b
+Signed-off-by: Jens Maus <mail at jens-maus.de>
+---
+ grub-core/fs/ext2.c | 10 +++++++++-
+ 1 file changed, 9 insertions(+), 1 deletion(-)
+
+diff --git a/grub-core/fs/ext2.c b/grub-core/fs/ext2.c
+index 0989e26e1..e1cc5e62a 100644
+--- a/grub-core/fs/ext2.c
++++ b/grub-core/fs/ext2.c
+@@ -104,6 +104,7 @@ GRUB_MOD_LICENSE ("GPLv3+");
+ #define EXT4_FEATURE_INCOMPAT_MMP 0x0100
+ #define EXT4_FEATURE_INCOMPAT_FLEX_BG 0x0200
+ #define EXT4_FEATURE_INCOMPAT_CSUM_SEED 0x2000
++#define EXT4_FEATURE_INCOMPAT_LARGEDIR 0x4000 /* >2GB or 3 level htree */
+ #define EXT4_FEATURE_INCOMPAT_ENCRYPT 0x10000
+
+ /* The set of back-incompatible features this driver DOES support. Add (OR)
+@@ -129,10 +130,17 @@ GRUB_MOD_LICENSE ("GPLv3+");
+ * 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.
++ * large_dir: Not back-incompatible given that the GRUB ext2 driver does
++ * not implement EXT2_FEATURE_COMPAT_DIR_INDEX. If the GRUB
++ * eventually supports the htree feature (aka dir_index)
++ * it should support 3 level htrees and then move
++ * EXT4_FEATURE_INCOMPAT_LARGEDIR to
++ * EXT2_DRIVER_SUPPORTED_INCOMPAT.
+ */
+ #define EXT2_DRIVER_IGNORED_INCOMPAT ( EXT3_FEATURE_INCOMPAT_RECOVER \
+ | EXT4_FEATURE_INCOMPAT_MMP \
+- | EXT4_FEATURE_INCOMPAT_CSUM_SEED)
++ | EXT4_FEATURE_INCOMPAT_CSUM_SEED \
++ | EXT4_FEATURE_INCOMPAT_LARGEDIR)
+
+ #define EXT3_JOURNAL_MAGIC_NUMBER 0xc03b3998U
+
+--
+2.34.1
+
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