On Fri, Apr 01, 2022 at 06:37:10AM -0400, Jeff Layton wrote:
> On Thu, 2022-03-31 at 20:03 +0000, Eric Biggers wrote:
> > On Thu, Mar 31, 2022 at 11:30:44AM -0400, Jeff Layton wrote:
> > > static struct fscrypt_operations ceph_fscrypt_ops = {
> > > .key_prefix = "ceph:",
> > > .get_context = ceph_crypt_get_context,
> > > .set_context = ceph_crypt_set_context,
> > > .empty_dir = ceph_crypt_empty_dir,
> > > + .has_stable_inodes = ceph_crypt_has_stable_inodes,
> > > };
> >
> > What is the use case for implementing this? Note the comment in the struct
> > definition:
> >
> > /*
> > * Check whether the filesystem's inode numbers and UUID are stable,
> > * meaning that they will never be changed even by offline operations
> > * such as filesystem shrinking and therefore can be used in the
> > * encryption without the possibility of files becoming unreadable.
> > *
> > * Filesystems only need to implement this function if they want to
> > * support the FSCRYPT_POLICY_FLAG_IV_INO_LBLK_{32,64} flags. These
> > * flags are designed to work around the limitations of UFS and eMMC
> > * inline crypto hardware, and they shouldn't be used in scenarios where
> > * such hardware isn't being used.
> > *
> > * Leaving this NULL is equivalent to always returning false.
> > */
> > bool (*has_stable_inodes)(struct super_block *sb);
> >
> > I think you should just leave this NULL for now.
> >
>
> Mostly we were just looking for ways to make all of the -g encrypt
> xfstests pass. I'll plan to drop this patch and 07/54. I don't see any
> need to support legacy modes or stuff that involves special storage hw.
Do generic/592 and generic/602 fail without this patch? If so, that would be a
test bug, since they should be skipped if the filesystem doesn't support
FSCRYPT_POLICY_FLAG_IV_INO_LBLK_{64,32}. I think that
_require_encryption_policy_support() should be already taking care of that,
though?
- Eric
