The NFSv4.1 protocol adds support for directory delegations, but it specifies that if you already have a delegation and try to request a new one on the same filehandle, the server must reply that the delegation is unavailable.
Add a new lease manager callback to allow the lease manager (nfsd in this case) to impose this extra check when performing a setlease. Signed-off-by: Jeff Layton <[email protected]> --- fs/locks.c | 5 +++++ include/linux/filelock.h | 14 ++++++++++++++ 2 files changed, 19 insertions(+) diff --git a/fs/locks.c b/fs/locks.c index edf34b9859a16c34dd75ce4d1a6a412dd426c875..8bd0faa384a9bdb0ef0ff40ba7269aed72439739 100644 --- a/fs/locks.c +++ b/fs/locks.c @@ -1826,6 +1826,11 @@ generic_add_lease(struct file *filp, int arg, struct file_lease **flp, void **pr continue; } + /* Allow the lease manager to veto the setlease */ + if (lease->fl_lmops->lm_may_setlease && + !lease->fl_lmops->lm_may_setlease(lease, fl)) + goto out; + /* * No exclusive leases if someone else has a lease on * this file: diff --git a/include/linux/filelock.h b/include/linux/filelock.h index c2ce8ba05d068b451ecf8f513b7e532819a29944..70079beddf61aa32ef01f1114cf0cb3ffaf2131a 100644 --- a/include/linux/filelock.h +++ b/include/linux/filelock.h @@ -49,6 +49,20 @@ struct lease_manager_operations { int (*lm_change)(struct file_lease *, int, struct list_head *); void (*lm_setup)(struct file_lease *, void **); bool (*lm_breaker_owns_lease)(struct file_lease *); + + /** + * lm_may_setlease - extra conditions for setlease + * @new: new file_lease being set + * @old: old (extant) file_lease + * + * This allows the lease manager to add extra conditions when + * setting a lease, based on the presence of an existing lease. + * + * Return values: + * %false: @new and @old conflict + * %true: No conflict detected + */ + bool (*lm_may_setlease)(struct file_lease *new, struct file_lease *old); }; struct lock_manager { -- 2.51.0
