NFSv4/pnfs: Return valid stateids in nfs_layout_find_inode_by_stateid()

Make sure to test the stateid for validity so that we catch instances
where the server may have been reusing stateids in
nfs_layout_find_inode_by_stateid().

Fixes: 7b410d9c ("pNFS: Delay getting the layout header in CB_LAYOUTRECALL handlers")
Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>

fs/nfs/callback_proc.c

@@ -128,6 +128,8 @@ static struct inode *nfs_layout_find_inode_by_stateid(struct nfs_client *clp,
 
 	list_for_each_entry_rcu(server, &clp->cl_superblocks, client_link) {
 		list_for_each_entry(lo, &server->layouts, plh_layouts) {
+			if (!pnfs_layout_is_valid(lo))
+				continue;
 			if (stateid != NULL &&
 			    !nfs4_stateid_match_other(stateid, &lo->plh_stateid))
 				continue;