[git pull] pile 5: simplifying ->d_name audits, easy part

[Al Viro <viro@zeniv.linux.org.uk>]

The last vfs-related pull request for tonight; there's an ->f_path counterpart
of that one, but I'd rather leave it for tomorrow - it's trickier and it would
be easier to deal with once work.mount gets merged.

A trivial conflict in fs/afs/internal.h...

The following changes since commit b320789d6883cc00ac78ce83bccbfe7ed58afcf0:

  Linux 6.17-rc4 (2025-08-31 15:33:07 -0700)

are available in the Git repository at:

  git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs.git tags/pull-qstr

for you to fetch changes up to 180a9cc3fd6a020746fbd7f97b9b62295a325fd2:

  make it easier to catch those who try to modify ->d_name (2025-09-15 21:08:33 -0400)

----------------------------------------------------------------
	Simplifying ->d_name audits, easy part.

Turn dentry->d_name into an anon union of const struct qsrt (d_name
itself) and a writable alias (__d_name).  With constification of some
struct qstr * arguments of functions that get &dentry->d_name passed
to them, that ends up with all modifications provably done only in
fs/dcache.c (and a fairly small part of it).

Any new places doing modifications will be easy to find - grep for
__d_name will suffice.

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

----------------------------------------------------------------
Al Viro (6):
      security_dentry_init_security(): constify qstr argument
      exfat_find(): constify qstr argument
      afs_edit_dir_{add,remove}(): constify qstr argument
      afs_dir_search: constify qstr argument
      generic_ci_validate_strict_name(): constify name argument
      make it easier to catch those who try to modify ->d_name

 fs/afs/dir_edit.c             |  4 ++--
 fs/afs/dir_search.c           |  2 +-
 fs/afs/internal.h             |  6 +++---
 fs/dcache.c                   | 26 +++++++++++++-------------
 fs/exfat/namei.c              |  2 +-
 include/linux/dcache.h        |  5 ++++-
 include/linux/fs.h            |  6 ++++--
 include/linux/lsm_hook_defs.h |  2 +-
 include/linux/security.h      |  4 ++--
 security/security.c           |  2 +-
 security/selinux/hooks.c      |  2 +-
 security/smack/smack_lsm.c    |  2 +-
 12 files changed, 34 insertions(+), 29 deletions(-)