NFS: Don't open code clearing of delegation state

Add a helper for the case when the nfs4 open state has been set to use
a delegation stateid, and we want to revert to using the open stateid.
Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>

fs/nfs/nfs4proc.c

@@ -1637,6 +1637,14 @@ static void nfs_state_set_delegation(struct nfs4_state *state,
 	write_sequnlock(&state->seqlock);
 }
 
+static void nfs_state_clear_delegation(struct nfs4_state *state)
+{
+	write_seqlock(&state->seqlock);
+	nfs4_stateid_copy(&state->stateid, &state->open_stateid);
+	clear_bit(NFS_DELEGATED_STATE, &state->flags);
+	write_sequnlock(&state->seqlock);
+}
+
 static int update_open_stateid(struct nfs4_state *state,
 		const nfs4_stateid *open_stateid,
 		const nfs4_stateid *delegation,
@@ -2145,10 +2153,7 @@ int nfs4_open_delegation_recall(struct nfs_open_context *ctx,
 	if (IS_ERR(opendata))
 		return PTR_ERR(opendata);
 	nfs4_stateid_copy(&opendata->o_arg.u.delegation, stateid);
-	write_seqlock(&state->seqlock);
-	nfs4_stateid_copy(&state->stateid, &state->open_stateid);
-	write_sequnlock(&state->seqlock);
-	clear_bit(NFS_DELEGATED_STATE, &state->flags);
+	nfs_state_clear_delegation(state);
 	switch (type & (FMODE_READ|FMODE_WRITE)) {
 	case FMODE_READ|FMODE_WRITE:
 	case FMODE_WRITE:
@@ -2601,10 +2606,7 @@ static void nfs_finish_clear_delegation_stateid(struct nfs4_state *state,
 		const nfs4_stateid *stateid)
 {
 	nfs_remove_bad_delegation(state->inode, stateid);
-	write_seqlock(&state->seqlock);
-	nfs4_stateid_copy(&state->stateid, &state->open_stateid);
-	write_sequnlock(&state->seqlock);
-	clear_bit(NFS_DELEGATED_STATE, &state->flags);
+	nfs_state_clear_delegation(state);
 }
 
 static void nfs40_clear_delegation_stateid(struct nfs4_state *state)
@@ -2672,13 +2674,14 @@ static void nfs41_check_delegation_stateid(struct nfs4_state *state)
 	delegation = rcu_dereference(NFS_I(state->inode)->delegation);
 	if (delegation == NULL) {
 		rcu_read_unlock();
+		nfs_state_clear_delegation(state);
 		return;
 	}
 
 	nfs4_stateid_copy(&stateid, &delegation->stateid);
 	if (test_bit(NFS_DELEGATION_REVOKED, &delegation->flags)) {
 		rcu_read_unlock();
-		nfs_finish_clear_delegation_stateid(state, &stateid);
+		nfs_state_clear_delegation(state);
 		return;
 	}