NFSv4: Don't reclaim delegations that have been returned or revoked

If the delegation has already been revoked, we want to avoid reclaiming
it on reboot.

Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>

fs/nfs/delegation.c

@@ -199,7 +199,7 @@ void nfs_inode_reclaim_delegation(struct inode *inode, const struct cred *cred,
 	delegation = rcu_dereference(NFS_I(inode)->delegation);
 	if (delegation != NULL) {
 		spin_lock(&delegation->lock);
-		if (delegation->inode != NULL) {
+		if (nfs4_is_valid_delegation(delegation, 0)) {
 			nfs4_stateid_copy(&delegation->stateid, stateid);
 			delegation->type = type;
 			delegation->pagemod_limit = pagemod_limit;