[git pull] d_revalidate pile (v2)

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

->d_revalidate() series, along with ->d_iname preliminary work.
One trivial conflict in fs/afs/dir.c - afs_do_lookup_one() has lost
one argument in mainline and switched another from dentry to qstr
in this series.

Change since the previous variant: made external_name.name word-aligned
and explicitly documented the layout constraints for struct external_name.

The following changes since commit 40384c840ea1944d7c5a392e8975ed088ecf0b37:

  Linux 6.13-rc1 (2024-12-01 14:28:56 -0800)

are available in the Git repository at:

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

for you to fetch changes up to 30d61efe118cad1a73ad2ad66a3298e4abdf9f41:

  9p: fix ->rename_sem exclusion (2025-01-27 19:25:24 -0500)

----------------------------------------------------------------
Provide stable parent and name to ->d_revalidate() instances

Most of the filesystem methods where we care about dentry name
and parent have their stability guaranteed by the callers;
->d_revalidate() is the major exception.

It's easy enough for callers to supply stable values for
expected name and expected parent of the dentry being
validated.  That kills quite a bit of boilerplate in
->d_revalidate() instances, along with a bunch of races
where they used to access ->d_name without sufficient
precautions.

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

----------------------------------------------------------------
Al Viro (20):
      make sure that DNAME_INLINE_LEN is a multiple of word size
      dcache: back inline names with a struct-wrapped array of unsigned long
      make take_dentry_name_snapshot() lockless
      dissolve external_name.u into separate members
      ext4 fast_commit: make use of name_snapshot primitives
      generic_ci_d_compare(): use shortname_storage
      Pass parent directory inode and expected name to ->d_revalidate()
      afs_d_revalidate(): use stable name and parent inode passed by caller
      ceph_d_revalidate(): use stable parent inode passed by caller
      ceph_d_revalidate(): propagate stable name down into request encoding
      fscrypt_d_revalidate(): use stable parent inode passed by caller
      exfat_d_revalidate(): use stable parent inode passed by caller
      vfat_revalidate{,_ci}(): use stable parent inode passed by caller
      fuse_dentry_revalidate(): use stable parent inode and name passed by caller
      gfs2_drevalidate(): use stable parent inode and name passed by caller
      nfs{,4}_lookup_validate(): use stable parent inode passed by caller
      nfs: fix ->d_revalidate() UAF on ->d_name accesses
      ocfs2_dentry_revalidate(): use stable parent inode and name passed by caller
      orangefs_d_revalidate(): use stable parent inode and name passed by caller
      9p: fix ->rename_sem exclusion

 Documentation/filesystems/locking.rst        |   7 +-
 Documentation/filesystems/porting.rst        |  16 +++++
 Documentation/filesystems/vfs.rst            |  24 ++++++-
 fs/9p/v9fs.h                                 |   2 +-
 fs/9p/vfs_dentry.c                           |  26 ++++++-
 fs/afs/dir.c                                 |  40 ++++-------
 fs/ceph/dir.c                                |  25 ++-----
 fs/ceph/mds_client.c                         |   9 ++-
 fs/ceph/mds_client.h                         |   2 +
 fs/coda/dir.c                                |   3 +-
 fs/crypto/fname.c                            |  22 ++----
 fs/dcache.c                                  | 103 ++++++++++++++++-----------
 fs/ecryptfs/dentry.c                         |  18 +++--
 fs/exfat/namei.c                             |  11 +--
 fs/ext4/fast_commit.c                        |  29 ++------
 fs/ext4/fast_commit.h                        |   3 +-
 fs/fat/namei_vfat.c                          |  19 +++--
 fs/fuse/dir.c                                |  20 +++---
 fs/gfs2/dentry.c                             |  31 ++++----
 fs/hfs/sysdep.c                              |   3 +-
 fs/jfs/namei.c                               |   3 +-
 fs/kernfs/dir.c                              |   3 +-
 fs/libfs.c                                   |  15 ++--
 fs/namei.c                                   |  18 ++---
 fs/nfs/dir.c                                 |  62 +++++++---------
 fs/nfs/namespace.c                           |   2 +-
 fs/nfs/nfs3proc.c                            |   5 +-
 fs/nfs/nfs4proc.c                            |  20 +++---
 fs/nfs/proc.c                                |   6 +-
 fs/ocfs2/dcache.c                            |  14 ++--
 fs/orangefs/dcache.c                         |  22 +++---
 fs/overlayfs/super.c                         |  22 +++++-
 fs/proc/base.c                               |   6 +-
 fs/proc/fd.c                                 |   3 +-
 fs/proc/generic.c                            |   6 +-
 fs/proc/proc_sysctl.c                        |   3 +-
 fs/smb/client/dir.c                          |   3 +-
 fs/tracefs/inode.c                           |   3 +-
 fs/vboxsf/dir.c                              |   3 +-
 include/linux/dcache.h                       |  23 ++++--
 include/linux/fscrypt.h                      |   7 +-
 include/linux/nfs_xdr.h                      |   2 +-
 tools/testing/selftests/bpf/progs/find_vma.c |   2 +-
 43 files changed, 359 insertions(+), 307 deletions(-)