From b925acb8f83d7ce3582b34018c05aae1be666abf Mon Sep 17 00:00:00 2001 From: Eric Biggers Date: Thu, 24 Oct 2019 14:54:37 -0700 Subject: 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 Signed-off-by: Eric Biggers --- fs/ext4/super.c | 14 ++++++++++++++ 1 file changed, 14 insertions(+) (limited to 'fs/ext4/super.c') diff --git a/fs/ext4/super.c b/fs/ext4/super.c index dd654e53ba3d..b3cbf8622eab 100644 --- a/fs/ext4/super.c +++ b/fs/ext4/super.c @@ -1345,6 +1345,18 @@ static bool ext4_dummy_context(struct inode *inode) return DUMMY_ENCRYPTION_ENABLED(EXT4_SB(inode->i_sb)); } +static bool ext4_has_stable_inodes(struct super_block *sb) +{ + return ext4_has_feature_stable_inodes(sb); +} + +static void ext4_get_ino_and_lblk_bits(struct super_block *sb, + int *ino_bits_ret, int *lblk_bits_ret) +{ + *ino_bits_ret = 8 * sizeof(EXT4_SB(sb)->s_es->s_inodes_count); + *lblk_bits_ret = 8 * sizeof(ext4_lblk_t); +} + static const struct fscrypt_operations ext4_cryptops = { .key_prefix = "ext4:", .get_context = ext4_get_context, @@ -1352,6 +1364,8 @@ static const struct fscrypt_operations ext4_cryptops = { .dummy_context = ext4_dummy_context, .empty_dir = ext4_empty_dir, .max_namelen = EXT4_NAME_LEN, + .has_stable_inodes = ext4_has_stable_inodes, + .get_ino_and_lblk_bits = ext4_get_ino_and_lblk_bits, }; #endif -- cgit v1.2.3-59-g8ed1b