Support more filesystems with FAN_REPORT_FID

Jan,

Following up on the plan laid out in this discussion, this patch set
implements the simpler and less controversial part of the plan to
enable AT_HANDLE_FID for all filesystems.

One filesystem that I tested which gained FAN_REPORT_FID support is 9p,
but there are many other filesystem for whom fanotify will become mostly
inotify drop-in replacement after this change.

Since the main goal of this change is to progress fanotify towards being
an inotify drop-in replacement, support for FAN_REPORT_FID with sb/mount
mark is at lower priority.

Because I think that support for FAN_REPORT_FID with sb/mount mark is
controversial with non-decodeable (AT_HANDLE_FID) file handles, I have
also disabled this feature that was added in v6.6-rc1 to ovelrayfs.

If you agree to this retroactive change, the path #1 should be fast
tracked into v6.6.

The rest of the changes should probably go in via the vfs tree after
review from you and nfsd maintainers.

Thanks,
Amir.

[1] https://lore.kernel.org/r/20230920110429.f4wkfuls73pd55pv...

Amir Goldstein (5):
  fanotify: limit reporting of event with non-decodeable file handles
  exportfs: add helpers to check if filesystem can encode/decode file
    handles
  exportfs: make ->encode_fh() a mandatory method for NFS export
  exportfs: define FILEID_INO64_GEN* file handle types
  exportfs: support encoding non-decodeable file handles by default

 Documentation/filesystems/nfs/exporting.rst |  7 +--
 Documentation/filesystems/porting.rst       |  9 ++++
 fs/affs/namei.c                             |  1 +
 fs/befs/linuxvfs.c                          |  1 +
 fs/efs/super.c                              |  1 +
 fs/erofs/super.c                            |  1 +
 fs/exportfs/expfs.c                         | 50 +++++++++++++++------
 fs/ext2/super.c                             |  1 +
 fs/ext4/super.c                             |  1 +
 fs/f2fs/super.c                             |  1 +
 fs/fat/nfs.c                                |  1 +
 fs/fhandle.c                                |  6 +--
 fs/fuse/inode.c                             |  7 +--
 fs/jffs2/super.c                            |  1 +
 fs/jfs/super.c                              |  1 +
 fs/nfsd/export.c                            |  3 +-
 fs/notify/fanotify/fanotify_user.c          | 25 +++++++----
 fs/ntfs/namei.c                             |  1 +
 fs/ntfs3/super.c                            |  1 +
 fs/overlayfs/util.c                         |  2 +-
 fs/smb/client/export.c                      |  9 ++--
 fs/squashfs/export.c                        |  1 +
 fs/ufs/super.c                              |  1 +
 include/linux/exportfs.h                    | 46 ++++++++++++++++++-
 24 files changed, 133 insertions(+), 45 deletions(-)

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2.34.1