[PATCH v6 00/20] nfsd: add support for CB_NOTIFY callbacks in directory delegations

[Jeff Layton <jlayton@kernel.org>]

This version of the patchset fixes up yet more problems that Sashiko
and Chuck flagged during review. Progress!

Please consider for v7.3. Original cover letter follows:

---------------------------------8<------------------------------------

This patchset builds on the directory delegation work we did a few
months ago to add support for CB_NOTIFY callbacks for some events. In
particular, creates, unlinks and renames. The server also sends updated
directory attributes in the notifications. With this support, the client
can register interest in a directory and get notifications about changes
within it without losing its lease.

The series starts with patches to allow the vfs to ignore certain types
of events on directories. nfsd can then request these sorts of
delegations on directories, and then set up inotify watches on the
directory to trigger sending CB_NOTIFY events.

This has mainly been tested with pynfs, with some new testcases that
I'll be posting soon. They seem to work fine with those tests, but I
don't think we'll want to merge these until we have a complete
client-side implementation to test against.

Signed-off-by: Jeff Layton <jlayton@kernel.org>
---
Changes in v6:
- fold earlier fix series into their respective patches
- tighten up RCU handling on fi_deleg_file
- move nfsd_fsnotify_recalc_mask() to filecache.c
- encoding failure now triggers deleg recall
- take snapshot of new dentry name when creating event
- Link to v5: https://lore.kernel.org/r/20260522-dir-deleg-v5-0-542cddfad576@kernel.org

Changes in v5:
- properly free dir delegation when alloc_pages_bulk() fails
- handle nfsd_file with no mark in nfsd_fsnotify_recalc_mask()
- nfsd_get_dir_deleg() should use stable nf pointer instead of
  depending on fi_deleg_file
- use GFP_NOFS in alloc_nfsd_notify_event() since it's called with locks
  held
- nfsd_handle_dir_event() tracepoint now handles NULL pointers safely
- Link to v4: https://lore.kernel.org/r/20260522-dir-deleg-v4-0-2acb883ac6bc@kernel.org

Changes in v4:
- Rebase onto Chuck's nfsd-testing branch. Minor contextual fixups.
- Link to v3: https://lore.kernel.org/r/20260428-dir-deleg-v3-0-5a0780ba9def@kernel.org

Changes in v3:
- Fix error handling in alloc_init_dir_deleg()
- Link to v2: https://lore.kernel.org/r/20260416-dir-deleg-v2-0-851426a550f6@kernel.org

Changes in v2:
- Fix __break_lease handling with different lease types on flc_lease list
- Add FSNOTIFY_EVENT_RENAME data type to properly handle cross-directory rename events
- Display fsnotify mask symbolically in tracepoints
- New tracepoint in fsnotify()
- Recalc fsnotify mask after unlocking lease instead of before
- Don't notify client that is making the changes
- After sending CB_NOTIFY, requeue if new events came in while running
- Document removal of NFS4_VERIFIER_SIZE/NFS4_FHSIZE from UAPI headers
- Properly release nfsd_dir_fsnotify_group on server shutdown
- Link to v1: https://lore.kernel.org/r/20260407-dir-deleg-v1-0-aaf68c478abd@kernel.org

---
Jeff Layton (20):
      nfsd: check fl_lmops in nfsd_breaker_owns_lease()
      nfsd: add protocol support for CB_NOTIFY
      nfs_common: add new NOTIFY4_* flags proposed in RFC8881bis
      nfsd: allow nfsd to get a dir lease with an ignore mask
      nfsd: update the fsnotify mark when setting or removing a dir delegation
      nfsd: make nfsd4_callback_ops->prepare operation bool return
      nfsd: add callback encoding and decoding linkages for CB_NOTIFY
      nfsd: use RCU to protect fi_deleg_file
      nfsd: add data structures for handling CB_NOTIFY
      nfsd: add notification handlers for dir events
      nfsd: apply the notify mask to the delegation when requested
      nfsd: add helper to marshal a fattr4 from completed args
      nfsd: allow nfsd4_encode_fattr4_change() to work with no export
      nfsd: send basic file attributes in CB_NOTIFY
      nfsd: allow encoding a filehandle into fattr4 without a svc_fh
      nfsd: add a fi_connectable flag to struct nfs4_file
      nfsd: add the filehandle to returned attributes in CB_NOTIFY
      nfsd: properly track requested child attributes
      nfsd: track requested dir attributes
      nfsd: add support to CB_NOTIFY for dir attribute changes

 Documentation/sunrpc/xdr/nfs4_1.x    | 262 ++++++++++++++-
 fs/nfsd/filecache.c                  | 122 ++++++-
 fs/nfsd/filecache.h                  |   3 +
 fs/nfsd/nfs4callback.c               |  97 +++++-
 fs/nfsd/nfs4layouts.c                |  10 +-
 fs/nfsd/nfs4proc.c                   |  17 +
 fs/nfsd/nfs4state.c                  | 590 ++++++++++++++++++++++++++++++----
 fs/nfsd/nfs4xdr.c                    | 330 +++++++++++++++++--
 fs/nfsd/nfs4xdr_gen.c                | 601 ++++++++++++++++++++++++++++++++++-
 fs/nfsd/nfs4xdr_gen.h                |  20 +-
 fs/nfsd/nfsfh.c                      |  10 +-
 fs/nfsd/nfsfh.h                      |   1 +
 fs/nfsd/state.h                      |  85 ++++-
 fs/nfsd/trace.h                      |  24 ++
 fs/nfsd/xdr4.h                       |   5 +
 fs/nfsd/xdr4cb.h                     |  12 +
 include/linux/nfs4.h                 | 127 --------
 include/linux/sunrpc/xdrgen/nfs4_1.h | 291 ++++++++++++++++-
 include/uapi/linux/nfs4.h            |   2 -
 19 files changed, 2339 insertions(+), 270 deletions(-)
---
base-commit: 8defc3ed26a2b4c8677ce2106c2c92cd26ef1316
change-id: 20260325-dir-deleg-339066dd1017

Best regards,
-- 
Jeff Layton <jlayton@kernel.org>