[PATCH 0/8] Revert setting casefolding dentry operations through s_d_op

When case-insensitive and fscrypt were adapted to work together, we moved the
code that sets the dentry operations for case-insensitive dentries(d_hash and
d_compare) to happen from a helper inside ->lookup.  This is because fscrypt
wants to set d_revalidate only on some dentries, so it does it only for them in
d_revalidate.

But, case-insensitive hooks are actually set on all dentries in the filesystem,
so the natural place to do it is through s_d_op and let d_alloc handle it [1].
In addition, doing it inside the ->lookup is a problem for case-insensitive
dentries that are not created through ->lookup, like those coming
open-by-fhandle[2], which will not see the required d_ops.

This patchset therefore reverts to using sb->s_d_op to set the dentry operations
for case-insensitive filesystems.  In order to set case-insensitive hooks early
and not require every dentry to have d_revalidate in case-insensitive
filesystems, it introduces a patch suggested by Al Viro to disable d_revalidate
on some dentries on the fly.

It survives fstests encrypt and quick groups without regressions.  Based on v6.7-rc1.

[1] https://lore.kernel.org/linux-fsdevel/20231123195327.GP38156@ZenIV/ (local)
[2] https://lore.kernel.org/linux-fsdevel/20231123171255.GN38156@ZenIV/ (local)

Gabriel Krisman Bertazi (8):
  dcache: Add helper to disable d_revalidate for a specific dentry
  fscrypt: Drop d_revalidate if key is available
  libfs: Merge encrypted_ci_dentry_ops and ci_dentry_ops
  libfs: Expose generic_ci_dentry_ops outside of libfs
  ext4: Set the case-insensitive dentry operations through ->s_d_op
  f2fs: Set the case-insensitive dentry operations through ->s_d_op
  libfs: Don't support setting casefold operations during lookup
  fscrypt: Move d_revalidate configuration back into fscrypt

 fs/crypto/fname.c       |  9 +++++-
 fs/crypto/hooks.c       |  8 ++++++
 fs/dcache.c             | 10 +++++++
 fs/ext4/namei.c         |  1 -
 fs/ext4/super.c         |  3 ++
 fs/f2fs/namei.c         |  1 -
 fs/f2fs/super.c         |  3 ++
 fs/libfs.c              | 64 +++--------------------------------------
 fs/ubifs/dir.c          |  1 -
 include/linux/dcache.h  |  1 +
 include/linux/fs.h      |  2 +-
 include/linux/fscrypt.h | 10 +++----
 12 files changed, 43 insertions(+), 70 deletions(-)

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2.43.0