Re: [PATCH 0/5] add support for direct I/O with fscrypt using blk-crypto

[Eric Biggers <ebiggers@kernel.org>]

On Thu, Jul 09, 2020 at 07:47:46PM +0000, Satya Tangirala wrote:
> This patch series adds support for direct I/O with fscrypt using
> blk-crypto. It has been rebased on fscrypt/inline-encryption.

Nit: use fscrypt/master instead.  (Eventually I'll delete the
"inline-encryption" branch.)

> 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.
> 
> 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. The only 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).

Note that xfstests has a check that prevents most of the direct I/O tests from
running when the 'test_dummy_encryption' mount option was specified:

_require_odirect()
{
        if [ $FSTYP = "ext4" ] || [ $FSTYP = "f2fs" ] ; then
                if echo "$MOUNT_OPTIONS" | grep -q "test_dummy_encryption"; then
                        _notrun "$FSTYP encryption doesn't support O_DIRECT"
                fi
        fi

We should try changing that check to not skip the test if the 'inlinecrypt'
mount option was also specified.

- Eric