NFSv4: Also ask for attributes when downgrading to a READ-only state

If we're downgrading from a READ+WRITE mode to a READ-only mode, then
ask for cache consistency attributes so that we avoid the revalidation
in nfs_close_context()

Fixes: 3947b74d0f9d ("NFSv4: Don't request a GETATTR on open_downgrade.")
Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>

fs/nfs/nfs4proc.c

@@ -3200,9 +3200,10 @@ static void nfs4_close_prepare(struct rpc_task *task, void *data)
 		goto out_wait;
 	}
 
-	if (calldata->arg.fmode == 0) {
+	if (calldata->arg.fmode == 0)
 		task->tk_msg.rpc_proc = &nfs4_procedures[NFSPROC4_CLNT_CLOSE];
 
+	if (calldata->arg.fmode == 0 || calldata->arg.fmode == FMODE_READ) {
 		/* Close-to-open cache consistency revalidation */
 		if (!nfs4_have_delegation(inode, FMODE_READ))
 			calldata->arg.bitmask = NFS_SERVER(inode)->cache_consistency_bitmask;