[PATCH v4 0/7] add support for direct I/O with fscrypt using blk-crypto

Satya Tangirala
2020-07-20T23:37:45Z

This patch series adds support for direct I/O with fscrypt using
blk-crypto. It has been rebased on fscrypt/master.

Patch 1 adds two functions to fscrypt that need to be called to determine
if direct I/O is supported for a request.

Patches 2 and 3 wire up direct-io and iomap respectively with the functions
introduced in Patch 1 and set bio crypt contexts on bios when appropriate
by calling into fscrypt.

Patches 4 and 5 allow ext4 and f2fs direct I/O to support fscrypt without
falling back to buffered I/O.

Patches 6 and 7 update the fscrypt documentation for inline encryption
support and direct I/O. The documentation now notes the required conditions
for inline encryption and direct I/O on encrypted files.

This patch series was tested by running xfstests with test_dummy_encryption
with and without the 'inlinecrypt' mount option, and there were no
meaningful regressions. One regression was for generic/587 on ext4,
but that test isn't compatible with test_dummy_encryption in the first
place, and the test "incorrectly" passes without the 'inlinecrypt' mount
option - a patch will be sent out to exclude that test when
test_dummy_encryption is turned on with ext4 (like the other quota related
tests that use user visible quota files). The other regression was for
generic/252 on ext4, which does direct I/O with a buffer aligned to the
block device's blocksize, but not necessarily aligned to the filesystem's
block size, which direct I/O with fscrypt requires.

Changes v3 => v4:
- Fix bug in iomap_dio_bio_actor() where fscrypt_limit_io_pages() was
being called too early (thanks Eric!)
- Improve comments and fix formatting in documentation
- iomap_dio_zero() is only called to zero out partial blocks, but
direct I/O is only supported on encrypted files when I/O is
blocksize aligned, so it doesn't need to set encryption contexts on
bios. Replace setting the encryption context with a WARN_ON(). (Eric)

Changes v2 => v3:
- add changelog to coverletter

Changes v1 => v2:
- Fix bug in f2fs caused by replacing f2fs_post_read_required() with
!fscrypt_dio_supported() since the latter doesn't check for
compressed inodes unlike the former.
- Add patches 6 and 7 for fscrypt documentation
- cleanups and comments

Eric Biggers (5):
fscrypt: Add functions for direct I/O support
direct-io: add support for fscrypt using blk-crypto
iomap: support direct I/O with fscrypt using blk-crypto
ext4: support direct I/O with fscrypt using blk-crypto
f2fs: support direct I/O with fscrypt using blk-crypto

Satya Tangirala (2):
fscrypt: document inline encryption support
fscrypt: update documentation for direct I/O support

Documentation/filesystems/fscrypt.rst | 36 +++++++++++-
fs/crypto/crypto.c | 8 +++
fs/crypto/inline_crypt.c | 82 +++++++++++++++++++++++++++
fs/direct-io.c | 15 ++++-
fs/ext4/file.c | 10 ++--
fs/f2fs/f2fs.h | 6 +-
fs/iomap/direct-io.c | 12 +++-
include/linux/fscrypt.h | 19 +++++++
8 files changed, 178 insertions(+), 10 deletions(-)

--
2.28.0.rc0.105.gf9edc3c819-goog