Hello, This patchset makes ext4 support encryption on filesystems where the filesystem block size is not equal to PAGE_SIZE. This allows e.g. PowerPC systems to use ext4 encryption. Most of the work for this was already done in prior kernel releases; now the only part missing is decryption support in block_read_full_page(). Chandan Rajendra has proposed a patchset "Consolidate FS read I/O callbacks code" [1] to address this and do various other things like make ext4 use mpage_readpages() again, and make ext4 and f2fs share more code. But it doesn't seem to be going anywhere. Therefore, I propose we simply add decryption support to block_read_full_page() for now. This is a fairly small change, and it gets ext4 encryption with subpage-sized blocks working. Note: to keep things simple I'm just allocating the work object from the bi_end_io function with GFP_ATOMIC. But if people think it's necessary, it could be changed to use preallocation like the page-based read path. Tested with 'gce-xfstests -c ext4/encrypt_1k -g auto', using the new "encrypt_1k" config I created. All tests pass except for those that already fail or are excluded with the encrypt or 1k configs, and 2 tests that try to create 1023-byte symlinks which fails since encrypted symlinks are limited to blocksize-3 bytes. Also ran the dedicated encryption tests using 'kvm-xfstests -c ext4/1k -g encrypt'; all pass, including the on-disk ciphertext verification tests. [1] https://lkml.kernel.org/linux-fsdevel/20190910155115.28550-1-chandan@xxxxxxxxxxxxx/T/#u Chandan Rajendra (1): ext4: Enable encryption for subpage-sized blocks Eric Biggers (1): fs/buffer.c: support fscrypt in block_read_full_page() Documentation/filesystems/fscrypt.rst | 4 +-- fs/buffer.c | 47 ++++++++++++++++++++++++--- fs/ext4/super.c | 7 ---- 3 files changed, 44 insertions(+), 14 deletions(-) -- 2.23.0
