On Tue, Oct 22, 2019 at 08:33:10PM -0700, Eric Biggers wrote: > 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 > > Changed v1 => v2: > - Added check for S_ISREG() which technically should be there, though > it happens not to matter currently. > > 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 | 48 ++++++++++++++++++++++++--- > fs/ext4/super.c | 7 ---- > 3 files changed, 45 insertions(+), 14 deletions(-) > Any more comments on this? Ted, are you interested in taking this through the ext4 tree for 5.5? - Eric
