filelock: add support for ignoring deleg breaks for dir change events

filelock: add support for ignoring deleg breaks for dir change events

If a NFS client requests a directory delegation with a notification
bitmask covering directory change events, the server shouldn't recall
the delegation. Instead the client will be notified of the change after
the fact.

Add support for ignoring lease breaks on directory changes. Add a new
flags parameter to try_break_deleg() and teach __break_lease how to
ignore certain types of delegation break events.

Reviewed-by: Jan Kara <jack@suse.cz>
Signed-off-by: Jeff Layton <jlayton@kernel.org>
Link: https://patch.msgid.link/20260428-dir-deleg-v3-2-5a0780ba9def@kernel.org
Acked-by: Chuck Lever <chuck.lever@oracle.com>
Signed-off-by: Christian Brauner <brauner@kernel.org>