This patch series adds support for direct I/O with fscrypt using blk-crypto. Till now, the blk-crypto-fallback expected the offset and length of each bvec in a bio to be aligned to the crypto data unit size. This in turn would mean that any user buffer used to read/write encrypted data using the blk-crypto framework would need to be aligned to the crypto data unit size. Patch 1 enables blk-crypto-fallback to work without this requirement. It also relaxes the alignment requirement that blk-crypto checks for - now, blk-crypto only requires that the length of the I/O is aligned to the crypto data unit size. This allows direct I/O support introduced in the later patches in this series to require extra alignment restrictions on user buffers. Patch 2 relaxes the alignment check that blk-crypto performs on bios. blk-crypto would check that the offset and length of each bvec in a bio is aligned to the data unit size, since the blk-crypto-fallback required it. As this is no longer the case, blk-crypto now only checks that the total length of the bio is data unit size aligned. Patch 3 adds two functions to fscrypt that need to be called to determine if direct I/O is supported for a request. Patches 4 and 5 modify direct-io and iomap respectively to set bio crypt contexts on bios when appropriate by calling into fscrypt. Patches 6 and 7 allow ext4 and f2fs direct I/O to support fscrypt without falling back to buffered I/O. Patch 8 updates the fscrypt documentation for direct I/O support. 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. Without any modification, xfstests skip any direct I/O test when using ext4/encrypt and f2fs/encrypt, so I modified xfstests not to skip those tests. Among those tests, generic/465 fails with ext4/encrypt because a bio ends up being split in the middle of a crypto data unit. Patch 1 from v7 (which has been sent out as a separate patch series) fixes this. Note that the blk-crypto-fallback changes (Patch 1 in v8 in this series) were also tested through xfstests by using this series along with the patch series that ensures bios aren't split in the middle of a data unit (Patch 1 from v7) - Some tests (such as generic/465 again) result in bvecs that don't contain a complete data unit (so a data unit is split across multiple bvecs), and only pass with this patch. Changes v7 => v8: - Patch 1 from v7 (which ensured that bios aren't split in the middle of a data unit) has been sent out in a separate patch series, as it's required even without this patch series. That patch series can now be found at https://lore.kernel.org/linux-block/20210114154723.2495814-1-satyat@xxxxxxxxxx/ - Patch 2 from v7 has been split into 2 patches (Patch 1 and 2 in v8). - Update docs Changes v6 => v7: - add patches 1 and 2 to allow blk-crypto to work with user buffers not aligned to crypto data unit size, so that direct I/O doesn't require that alignment either. - some cleanups Changes v5 => v6: - fix bug with fscrypt_limit_io_blocks() and make it ready for 64 bit block numbers. - remove Reviewed-by for Patch 1 due to significant changes from when the Reviewed-by was given. Changes v4 => v5: - replace fscrypt_limit_io_pages() with fscrypt_limit_io_block(), which is now called by individual filesystems (currently only ext4) instead of the iomap code. This new function serves the same end purpose as the one it replaces (ensuring that DUNs within a bio are contiguous) but operates purely with blocks instead of with pages. - make iomap_dio_zero() set bio_crypt_ctx's again, instead of just a WARN_ON() since some folks prefer that instead. - add Reviewed-by's 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 (3): block: blk-crypto-fallback: handle data unit split across multiple bvecs block: blk-crypto: relax alignment requirements for bvecs in bios fscrypt: update documentation for direct I/O support Documentation/filesystems/fscrypt.rst | 21 ++- block/blk-crypto-fallback.c | 203 ++++++++++++++++++++------ block/blk-crypto.c | 19 +-- fs/crypto/crypto.c | 8 + fs/crypto/inline_crypt.c | 74 ++++++++++ fs/direct-io.c | 15 +- fs/ext4/file.c | 10 +- fs/ext4/inode.c | 7 + fs/f2fs/f2fs.h | 6 +- fs/iomap/direct-io.c | 6 + include/linux/fscrypt.h | 18 +++ 11 files changed, 315 insertions(+), 72 deletions(-) -- 2.30.0.280.ga3ce27912f-goog
