ext4: add support for IV_INO_LBLK_64 encryption policies
IV_INO_LBLK_64 encryption policies have special requirements from the
filesystem beyond those of the existing encryption policies:
- Inode numbers must never change, even if the filesystem is resized.
- Inode numbers must be <= 32 bits.
- File logical block numbers must be <= 32 bits.
ext4 has 32-bit inode and file logical block numbers. However,
resize2fs can re-number inodes when shrinking an ext4 filesystem.
However, typically the people who would want to use this format don't
care about filesystem shrinking. They'd be fine with a solution that
just prevents the filesystem from being shrunk.
Therefore, add a new feature flag EXT4_FEATURE_COMPAT_STABLE_INODES that
will do exactly that. Then wire up the fscrypt_operations to expose
this flag to fs/crypto/, so that it allows IV_INO_LBLK_64 policies when
this flag is set.
Acked-by: Theodore Ts'o <tytso@mit.edu>
Signed-off-by: Eric Biggers <ebiggers@google.com>
diff --git a/fs/ext4/ext4.h b/fs/ext4/ext4.h
index 03db3e7..b3a2cc7 100644
--- a/fs/ext4/ext4.h
+++ b/fs/ext4/ext4.h
@@ -1678,6 +1678,7 @@ static inline bool ext4_verity_in_progress(struct inode *inode)
#define EXT4_FEATURE_COMPAT_RESIZE_INODE 0x0010
#define EXT4_FEATURE_COMPAT_DIR_INDEX 0x0020
#define EXT4_FEATURE_COMPAT_SPARSE_SUPER2 0x0200
+#define EXT4_FEATURE_COMPAT_STABLE_INODES 0x0800
#define EXT4_FEATURE_RO_COMPAT_SPARSE_SUPER 0x0001
#define EXT4_FEATURE_RO_COMPAT_LARGE_FILE 0x0002
@@ -1779,6 +1780,7 @@ EXT4_FEATURE_COMPAT_FUNCS(xattr, EXT_ATTR)
EXT4_FEATURE_COMPAT_FUNCS(resize_inode, RESIZE_INODE)
EXT4_FEATURE_COMPAT_FUNCS(dir_index, DIR_INDEX)
EXT4_FEATURE_COMPAT_FUNCS(sparse_super2, SPARSE_SUPER2)
+EXT4_FEATURE_COMPAT_FUNCS(stable_inodes, STABLE_INODES)
EXT4_FEATURE_RO_COMPAT_FUNCS(sparse_super, SPARSE_SUPER)
EXT4_FEATURE_RO_COMPAT_FUNCS(large_file, LARGE_FILE)