Re: [RFC][PATCH 0/4] Prepare for supporting more filesystems with fanotify

[Chuck Lever <cel@kernel.org>]

On Tue, Apr 25, 2023 at 04:01:01PM +0300, Amir Goldstein wrote:
> Jan,
> 
> Following up on the FAN_REPORT_ANY_FID proposal [1], here is a shot at an
> alternative proposal to seamlessly support more filesystems.
> 
> While fanotify relaxes the requirements for filesystems to support
> reporting fid to require only the ->encode_fh() operation, there are
> currently no new filesystems that meet the relaxed requirements.
> 
> I will shortly post patches that allow overlayfs to meet the new
> requirements with default overlay configurations.
> 
> The overlay and vfs/fanotify patch sets are completely independent.
> The are both available on my github branch [2] and there is a simple
> LTP test variant that tests reporting fid from overlayfs [3], which
> also demonstrates the minor UAPI change of name_to_handle_at(2) for
> requesting a non-decodeable file handle by userspace.
> 
> Thanks,
> Amir.
> 
> [1] https://lore.kernel.org/linux-fsdevel/20230417162721.ouzs33oh6mb7vtft@quack3/
> [2] https://github.com/amir73il/linux/commits/exportfs_encode_fid
> [3] https://github.com/amir73il/ltp/commits/exportfs_encode_fid
> 
> Amir Goldstein (4):
>   exportfs: change connectable argument to bit flags
>   exportfs: add explicit flag to request non-decodeable file handles
>   exportfs: allow exporting non-decodeable file handles to userspace
>   fanotify: support reporting non-decodeable file handles
> 
>  Documentation/filesystems/nfs/exporting.rst |  4 +--
>  fs/exportfs/expfs.c                         | 29 ++++++++++++++++++---
>  fs/fhandle.c                                | 20 ++++++++------
>  fs/nfsd/nfsfh.c                             |  5 ++--
>  fs/notify/fanotify/fanotify.c               |  4 +--
>  fs/notify/fanotify/fanotify_user.c          |  6 ++---
>  fs/notify/fdinfo.c                          |  2 +-
>  include/linux/exportfs.h                    | 18 ++++++++++---
>  include/uapi/linux/fcntl.h                  |  5 ++++
>  9 files changed, 67 insertions(+), 26 deletions(-)

Hello Amir-

Note that the maintainers of exportfs are Jeff and myself. Please
copy us on future versions of this patch series. Thanks!

[cel@klimt even-releases]$ scripts/get_maintainer.pl fs/exportfs/
Chuck Lever <chuck.lever@oracle.com> (supporter:KERNEL NFSD, SUNRPC, AND LOCKD SERVERS)
Jeff Layton <jlayton@kernel.org> (supporter:KERNEL NFSD, SUNRPC, AND LOCKD SERVERS)
linux-nfs@vger.kernel.org (open list:KERNEL NFSD, SUNRPC, AND LOCKD SERVERS)
linux-kernel@vger.kernel.org (open list)