Jan, Following v2 incorporates a few fixes and ACKs from review of v1 [1]. 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. Patches to add ->encode_fh() to overlay with default configuation are available on my github branch [2]. I will re-post them after this patch set will be approved. Based on the discussion on the UAPI alternatives, I kept the AT_HANDLE_FID UAPI, which seems the simplest of them all. There is an LTP test [3] that tests reporting fid from overlayfs, which also demonstrates the use of AT_HANDLE_FID for requesting a non-decodeable file handle by userspace and there is a man page draft [4] for the documentation of the AT_HANDLE_FID flags. Thanks, Amir. Changes since v1: - Fixes to Kerneldoc (Chuck) - Added ACKs (Chuck,Jeff) - Explain the logic of requiring ->s_export_op (Jan) - Added man page draft [1] https://lore.kernel.org/linux-fsdevel/20230425130105.2606684-1-amir73il@xxxxxxxxx/ [2] https://github.com/amir73il/linux/commits/exportfs_encode_fid [3] https://github.com/amir73il/ltp/commits/exportfs_encode_fid [4] https://github.com/amir73il/man-pages/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 | 33 ++++++++++++++++++--- fs/fhandle.c | 22 +++++++++----- fs/nfsd/nfsfh.c | 5 ++-- fs/notify/fanotify/fanotify.c | 4 +-- fs/notify/fanotify/fanotify_user.c | 7 ++--- fs/notify/fdinfo.c | 2 +- include/linux/exportfs.h | 18 +++++++++-- include/uapi/linux/fcntl.h | 5 ++++ 9 files changed, 74 insertions(+), 26 deletions(-) -- 2.34.1