linux-ext4 - [PATCH v4 00/12] Set casefold/fscrypt dentry operations through sb->s_d

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Date: Fri, 26 Jan 2024 21:10:00 -0300
From: Gabriel Krisman Bertazi <krisman@...e.de>
To: ebiggers@...nel.org,
	viro@...iv.linux.org.uk,
	jaegeuk@...nel.org,
	tytso@....edu
Cc: amir73il@...il.com,
	linux-ext4@...r.kernel.org,
	linux-f2fs-devel@...ts.sourceforge.net,
	linux-fsdevel@...r.kernel.org,
	Gabriel Krisman Bertazi <krisman@...e.de>
Subject: [PATCH v4 00/12] Set casefold/fscrypt dentry operations through sb->s_d_op

Hi,

The v4 of this patchset addresses the issues Eric pointed out in the
previous version.  The patch merging the fscrypt lookup helpers was
completely rewritten to avoid the race condition; We also now return
immediately from __fscrypt_handle_d_move; Finally, the overlayfs patch
message was improved.  Further details can be found on the changelog of
each patch.

As usual, this survived fstests on ext4 and f2fs.

---
original cover letter:

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/
[2] https://lore.kernel.org/linux-fsdevel/20231123171255.GN38156@ZenIV/

Gabriel Krisman Bertazi (12):
  ovl: Reject mounting over case-insensitive directories
  fscrypt: Factor out a helper to configure the lookup dentry
  fscrypt: Call fscrypt_prepare_lookup_dentry on unencrypted dentries
  fscrypt: Drop d_revalidate for valid dentries during lookup
  fscrypt: Drop d_revalidate once the key is added
  fscrypt: Ignore non-fscrypt volumes during d_move
  libfs: Merge encrypted_ci_dentry_ops and ci_dentry_ops
  libfs: Add helper to choose dentry operations at mount-time
  ext4: Configure dentry operations at dentry-creation time
  f2fs: Configure dentry operations at dentry-creation time
  ubifs: Configure dentry operations at dentry-creation time
  libfs: Drop generic_set_encrypted_ci_d_ops

 fs/crypto/hooks.c       | 28 ++++-----------
 fs/ext4/namei.c         |  1 -
 fs/ext4/super.c         |  1 +
 fs/f2fs/namei.c         |  1 -
 fs/f2fs/super.c         |  1 +
 fs/libfs.c              | 62 +++++++++-----------------------
 fs/overlayfs/params.c   | 14 ++++++--
 fs/ubifs/dir.c          |  1 -
 fs/ubifs/super.c        |  1 +
 include/linux/fs.h      | 11 +++++-
 include/linux/fscrypt.h | 78 +++++++++++++++++++++++++++++------------
 11 files changed, 103 insertions(+), 96 deletions(-)

-- 
2.43.0