Wire up ext4 to support inline encryption via the helper functions which
fs/crypto/ now provides. This includes:
- Adding a mount option 'inlinecrypt' which enables inline encryption
on encrypted files where it can be used.
- Setting the bio_crypt_ctx on bios that will be submitted to an
inline-encrypted file.
Note: submit_bh_wbc() in fs/buffer.c also needed to be patched for
this part, since ext4 sometimes uses ll_rw_block() on file data.
- Not adding logically discontiguous data to bios that will be submitted
to an inline-encrypted file.
- Not doing filesystem-layer crypto on inline-encrypted files.
Co-developed-by: Satya Tangirala <satyat@google.com>
Signed-off-by: Satya Tangirala <satyat@google.com>
Reviewed-by: Theodore Ts'o <tytso@mit.edu>
Link: https://lore.kernel.org/r/20200702015607.1215430-5-satyat@google.com
Signed-off-by: Eric Biggers <ebiggers@google.com>