[PATCH 0/5] Add the test_dummy_encryption key on-demand

[Eric Biggers <ebiggers@kernel.org>]

This series eliminates the call to fscrypt_destroy_keyring() from
__put_super(), which is causing confusion because it looks like (but
actually isn't) a sleep-in-atomic bug.  See the thread "block: sleeping
in atomic warnings", i.e.
https://lore.kernel.org/linux-fsdevel/CAHk-=wg6ohuyrmLJYTfEpDbp2Jwnef54gkcpZ3-BYgy4C6UxRQ@mail.gmail.com
and its responses.

To do this, this series makes it so that the key associated with the
"test_dummy_encryption" mount option is added on-demand when files are
accessed, instead of immediately when the filesystem is mounted.

I was going back and forth between this solution and instead having ext4
and f2fs call fscrypt_destroy_keyring() on ->fill_super failure.  (Or
using Linus's suggestion of adding the test dummy key as the very last
step of ->fill_super.)  It does seem ideal to add the key at mount time,
but I ended up going with this solution instead because it reduces the
number of things the individual filesystems have to handle.

Eric Biggers (5):
  fscrypt: add the test dummy encryption key on-demand
  ext4: stop calling fscrypt_add_test_dummy_key()
  f2fs: stop calling fscrypt_add_test_dummy_key()
  fs/super.c: stop calling fscrypt_destroy_keyring() from __put_super()
  fscrypt: clean up fscrypt_add_test_dummy_key()

 fs/crypto/fscrypt_private.h |  4 ++++
 fs/crypto/keyring.c         | 26 +++++++-------------------
 fs/crypto/keysetup.c        | 23 +++++++++++++++++++++--
 fs/crypto/policy.c          |  3 +--
 fs/ext4/super.c             | 13 +------------
 fs/f2fs/super.c             |  6 ------
 fs/super.c                  |  1 -
 include/linux/fscrypt.h     |  9 ---------
 8 files changed, 34 insertions(+), 51 deletions(-)


base-commit: 6d796c50f84ca79f1722bb131799e5a5710c4700
-- 
2.39.1