On Wed, Sep 16, 2020 at 09:11:23PM -0700, Eric Biggers wrote: > Hello, > > This series reworks the implementation of creating new encrypted files > by introducing new helper functions that allow filesystems to set up the > inodes' keys earlier, prior to taking too many filesystem locks. > > This fixes deadlocks that are possible during memory reclaim because > fscrypt_get_encryption_info() isn't GFP_NOFS-safe, yet it's called > during an ext4 transaction or under f2fs_lock_op(). It also fixes a > similar deadlock where f2fs can try to recursively lock a page when the > test_dummy_encryption mount option is in use. > > It also solves an ordering problem that the ceph support for fscrypt > will have. For more details about this ordering problem, see the > discussion on Jeff Layton's RFC patchsets for ceph fscrypt support > (v1: https://lkml.kernel.org/linux-fscrypt/20200821182813.52570-1-jlayton@xxxxxxxxxx/T/#u > v2: https://lkml.kernel.org/linux-fscrypt/20200904160537.76663-1-jlayton@xxxxxxxxxx/T/#u > v3: https://lkml.kernel.org/linux-fscrypt/20200914191707.380444-1-jlayton@xxxxxxxxxx/T/#u) > Note that v3 of the ceph patchset is based on v2 of this patchset. > > Patch 1 adds the above-mentioned new helper functions. Patches 2-5 > convert ext4, f2fs, and ubifs to use them, and patches 6-9 clean up a > few things afterwards. > > Finally, patches 10-13 change the implementation of > test_dummy_encryption to no longer set up an encryption key for > unencrypted directories, which was confusing and was causing problems. > > This patchset applies to the master branch of > https://git.kernel.org/pub/scm/fs/fscrypt/fscrypt.git. > It can also be retrieved from tag "fscrypt-file-creation-v3" of > https://git.kernel.org/pub/scm/linux/kernel/git/ebiggers/linux.git. > > I'm looking to apply this for 5.10; reviews are greatly appreciated! > > Changed v2 => v3: > - Added patch that changes fscrypt_set_test_dummy_encryption() to take > a 'const char *'. (Needed by ceph.) > - Fixed bug where fscrypt_prepare_new_inode() succeeded even if the > new inode's key couldn't be set up. > - Fixed bug where fscrypt_prepare_new_inode() wouldn't derive the > dirhash key for new casefolded directories. > - Made warning messages account for i_ino possibly being 0 now. > > Changed v1 => v2: > - Added mention of another deadlock this fixes. > - Added patches to improve the test_dummy_encryption implementation. > - Dropped an ext4 cleanup patch that can be done separately later. > - Lots of small cleanups, and a couple small fixes. > > Eric Biggers (13): > fscrypt: add fscrypt_prepare_new_inode() and fscrypt_set_context() > ext4: factor out ext4_xattr_credits_for_new_inode() > ext4: use fscrypt_prepare_new_inode() and fscrypt_set_context() > f2fs: use fscrypt_prepare_new_inode() and fscrypt_set_context() > ubifs: use fscrypt_prepare_new_inode() and fscrypt_set_context() > fscrypt: adjust logging for in-creation inodes > fscrypt: remove fscrypt_inherit_context() > fscrypt: require that fscrypt_encrypt_symlink() already has key > fscrypt: stop pretending that key setup is nofs-safe > fscrypt: make "#define fscrypt_policy" user-only > fscrypt: move fscrypt_prepare_symlink() out-of-line > fscrypt: handle test_dummy_encryption in more logical way > fscrypt: make fscrypt_set_test_dummy_encryption() take a 'const char > *' All applied to fscrypt.git#master for 5.10. I'd still really appreciate more reviews and acks, though. - Eric
