1 files changed, 10 insertions, 2 deletions

diff --git a/fs/nfs/nfs42xdr.c b/fs/nfs/nfs42xdr.c
index 6dc6f2aea0d6..8b2605882a20 100644
--- a/fs/nfs/nfs42xdr.c
+++ b/fs/nfs/nfs42xdr.c
@@ -330,13 +330,21 @@ static int decode_write_response(struct xdr_stream *xdr,
                                  struct nfs42_write_res *res)
 {
         __be32 *p;
-        int stateids;
 
         p = xdr_inline_decode(xdr, 4 + 8 + 4);
         if (unlikely(!p))
                 goto out_overflow;
 
-        stateids = be32_to_cpup(p++);
+        /*
+         * We never use asynchronous mode, so warn if a server returns
+         * a stateid.
+         */
+        if (unlikely(*p != 0)) {
+                pr_err_once("%s: server has set unrequested "
+                                "asynchronous mode\n", __func__);
+                return -EREMOTEIO;
+        }
+        p++;
         p = xdr_decode_hyper(p, &res->count);
         res->verifier.committed = be32_to_cpup(p);
         return decode_verifier(xdr, &res->verifier.verifier);