fscrypt: support for inline-encryption-optimized policies

Hello,

In preparation for adding inline encryption support to fscrypt, this patchset adds a new fscrypt policy flag which modifies the encryption to be optimized for inline encryption hardware compliant with the UFS standard --- specifically, to use a smaller number of keys while still using at most 64 IV bits. This required adding the inode number to the IVs. For ext4, this precludes filesystem shrinking, so I've also added a compat feature which will prevent the filesystem from being shrunk.

I've separated this from the full "Inline Encryption Support" patchset
(https://lkml.kernel.org/linux-fsdevel/[email protected]/)
to avoid conflating an implementation (inline encryption) with a new on-disk format (INLINE_CRYPT_OPTIMIZED). This patchset purely adds support for INLINE_CRYPT_OPTIMIZED policies to fscrypt, but implements them using the existing filesystem layer crypto.

We're planning to make the *implementation* (filesystem layer or inline crypto) be controlled by a mount option '-o inlinecrypt'.

This patchset applies to fscrypt.git#master and can also be retrieved from
https://git.kernel.org/pub/scm/linux/kernel/git/ebiggers/linux.git/log/?h=inline-crypt-optimized-v1

A ciphertext verification test for INLINE_CRYPT_OPTIMIZED policies can be found at
https://git.kernel.org/pub/scm/linux/kernel/git/ebiggers/xfstests-dev.git/log/?h=inline-encryption

Work-in-progress patches for the inline encryption implementation of both INLINE_CRYPT_OPTIMIZED and regular policies can be found at
https://git.kernel.org/pub/scm/linux/kernel/git/ebiggers/linux.git/log/?h=inline-encryption-wip

Eric Biggers (3):
fscrypt: add support for inline-encryption-optimized policies
ext4: add support for INLINE_CRYPT_OPTIMIZED encryption policies
f2fs: add support for INLINE_CRYPT_OPTIMIZED encryption policies

 Documentation/filesystems/fscrypt.rst | 53 +++++++++++++++++++--------
 fs/crypto/crypto.c                    | 11 +++++-
 fs/crypto/fscrypt_private.h           | 20 +++++++---
 fs/crypto/keyring.c                   |  6 ++-
 fs/crypto/keysetup.c                  | 47 +++++++++++++++++++-----
 fs/crypto/policy.c                    | 42 ++++++++++++++++++++-
 fs/ext4/ext4.h                        |  2 +
 fs/ext4/super.c                       | 14 +++++++
 fs/f2fs/super.c                       | 26 ++++++++++---
 include/linux/fscrypt.h               |  3 ++
 include/uapi/linux/fscrypt.h          | 15 ++++----
 11 files changed, 191 insertions(+), 48 deletions(-)

2.23.0.866.gb869b98d4c-goog