SUNRPC: Don't try to parse incomplete RPC messages

If the copy of the RPC reply into our buffers did not complete, and
we could end up with a truncated message. In that case, just resend
the call.

Fixes: a0584ee9aed80 ("SUNRPC: Use struct xdr_stream when decoding...")
Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>

1 files changed, 13 insertions, 1 deletions

diff --git a/net/sunrpc/clnt.c b/net/sunrpc/clnt.c
index 44d5cf318813..8b622ceb1158 100644
--- a/net/sunrpc/clnt.c
+++ b/net/sunrpc/clnt.c
@@ -2465,6 +2465,7 @@ call_decode(struct rpc_task *task)
         struct rpc_clnt *clnt = task->tk_client;
         struct rpc_rqst *req = task->tk_rqstp;
         struct xdr_stream xdr;
+        int err;
 
         dprint_status(task);
 
@@ -2487,6 +2488,15 @@ call_decode(struct rpc_task *task)
          * before it changed req->rq_reply_bytes_recvd.
          */
         smp_rmb();
+
+        /*
+         * Did we ever call xprt_complete_rqst()? If not, we should assume
+         * the message is incomplete.
+         */
+        err = -EAGAIN;
+        if (!req->rq_reply_bytes_recvd)
+                goto out;
+
         req->rq_rcv_buf.len = req->rq_private_buf.len;
 
         /* Check that the softirq receive buffer is valid */
@@ -2495,7 +2505,9 @@ call_decode(struct rpc_task *task)
 
         xdr_init_decode(&xdr, &req->rq_rcv_buf,
                         req->rq_rcv_buf.head[0].iov_base, req);
-        switch (rpc_decode_header(task, &xdr)) {
+        err = rpc_decode_header(task, &xdr);
+out:
+        switch (err) {
         case 0:
                 task->tk_action = rpc_exit_task;
                 task->tk_status = rpcauth_unwrap_resp(task, &xdr);