[PATCH RFC v17 03/11] NFSD: Add lm_lock_expired call out

[Dai Ngo <dai.ngo@oracle.com>]

Add callout function nfsd4_lm_lock_expired for lm_lock_expired.
If lock request has conflict with courtesy client then expire the
courtesy client and return no conflict to caller.

Signed-off-by: Dai Ngo <dai.ngo@oracle.com>
---
 fs/nfsd/nfs4state.c | 22 ++++++++++++++++++++++
 fs/nfsd/state.h     | 14 ++++++++++++++
 2 files changed, 36 insertions(+)

diff --git a/fs/nfsd/nfs4state.c b/fs/nfsd/nfs4state.c
index a65d59510681..80772662236b 100644
--- a/fs/nfsd/nfs4state.c
+++ b/fs/nfsd/nfs4state.c
@@ -6578,10 +6578,32 @@ nfsd4_lm_notify(struct file_lock *fl)
 	}
 }
 
+/**
+ * nfsd4_lm_lock_expired - check if lock conflict can be resolved.
+ *
+ * @fl: pointer to file_lock with a potential conflict
+ * Return values:
+ *   %false: real conflict, lock conflict can not be resolved.
+ *   %true: no conflict, lock conflict was resolved.
+ *
+ * Note that this function is called while the flc_lock is held.
+ */
+static bool
+nfsd4_lm_lock_expired(struct file_lock *fl)
+{
+	struct nfs4_lockowner *lo;
+
+	if (!fl)
+		return false;
+	lo = (struct nfs4_lockowner *)fl->fl_owner;
+	return nfsd4_expire_courtesy_clnt(lo->lo_owner.so_client);
+}
+
 static const struct lock_manager_operations nfsd_posix_mng_ops  = {
 	.lm_notify = nfsd4_lm_notify,
 	.lm_get_owner = nfsd4_lm_get_owner,
 	.lm_put_owner = nfsd4_lm_put_owner,
+	.lm_lock_expired = nfsd4_lm_lock_expired,
 };
 
 static inline void
diff --git a/fs/nfsd/state.h b/fs/nfsd/state.h
index 40e390abc842..d156ae3ab46c 100644
--- a/fs/nfsd/state.h
+++ b/fs/nfsd/state.h
@@ -735,4 +735,18 @@ extern void nfsd4_client_record_remove(struct nfs4_client *clp);
 extern int nfsd4_client_record_check(struct nfs4_client *clp);
 extern void nfsd4_record_grace_done(struct nfsd_net *nn);
 
+static inline bool
+nfsd4_expire_courtesy_clnt(struct nfs4_client *clp)
+{
+	bool rc = false;
+
+	spin_lock(&clp->cl_cs_lock);
+	if (clp->cl_cs_client_state == NFSD4_CLIENT_COURTESY)
+		clp->cl_cs_client_state = NFSD4_CLIENT_EXPIRED;
+	if (clp->cl_cs_client_state == NFSD4_CLIENT_EXPIRED)
+		rc = true;
+	spin_unlock(&clp->cl_cs_lock);
+	return rc;
+}
+
 #endif   /* NFSD4_STATE_H */
-- 
2.9.5