From f0372dde6a0a6e7de7d0a7c2002d0282df6101eb Mon Sep 17 00:00:00 2001
From: Masayuki Ishikawa <masayuki.ishikawa@gmail.com>
Date: Tue, 11 May 2021 10:25:26 +0900
Subject: [PATCH] fs: nfs: Fix rpcclnt_send() in TCP mode

Summary:
- I noticed that NFS over TCP does not work with Ubuntu 18.04
- Finally, I found that the record marking packet should not
  be sent separately
- This commit fixes this issue

Impact:
- TCP mode only

Testing:
- Tested with NFS server on Ubuntu 18.04 (x86_64)
- Tested with spresense:rndis (defconfig will be updated later)

Signed-off-by: Masayuki Ishikawa <Masayuki.Ishikawa@jp.sony.com>
---
 fs/nfs/rpc_clnt.c | 51 +++++++++++++++++++++++++++++++----------------
 1 file changed, 34 insertions(+), 17 deletions(-)

diff --git a/fs/nfs/rpc_clnt.c b/fs/nfs/rpc_clnt.c
index f57fed23bf0..93579667a45 100644
--- a/fs/nfs/rpc_clnt.c
+++ b/fs/nfs/rpc_clnt.c
@@ -297,32 +297,49 @@ bad:
 static int rpcclnt_send(FAR struct rpcclnt *rpc,
                         FAR void *call, int reqlen)
 {
+  struct iovec  iov[2];
+  struct msghdr msg;
   uint32_t mark;
   int ret = OK;
 
-  /* Send the record marking(RM) for stream only */
-
   if (rpc->rc_sotype == SOCK_STREAM)
     {
-      mark = txdr_unsigned(0x80000000 | reqlen);
-      ret = psock_send(&rpc->rc_so, &mark, sizeof(mark), 0);
-      if (ret < 0)
-        {
-          ferr("ERROR: psock_send mark failed: %d\n", ret);
-          return ret;
-        }
+      /* Prepare the record marking(RM) and compose an RPC request
+       * NOTE: Sending a separate packet does not work with Linux host
+       */
+
+      mark = txdr_unsigned(0x80000000 | (reqlen));
+
+      iov[0].iov_base = (FAR void *)&mark;
+      iov[0].iov_len = sizeof(mark);
+      iov[1].iov_base = (FAR void *)call;
+      iov[1].iov_len = reqlen;
+
+      msg.msg_name = NULL;
+      msg.msg_namelen = 0;
+      msg.msg_iov = iov;
+      msg.msg_iovlen = 2;
+      msg.msg_control = NULL;
+      msg.msg_controllen = 0;
+      msg.msg_flags = 0;
+
+      ret = psock_sendmsg(&rpc->rc_so, &msg, 0);
+      ferr("ERROR: psock_sendmsg request failed: %d\n", ret);
+    }
+  else
+    {
+      /* Send the call message
+       *
+       * On success, psock_send returns the number of bytes sent;
+       * On failure, it returns a negated errno value.
+       */
+
+      ret = psock_send(&rpc->rc_so, call, reqlen, 0);
+      ferr("ERROR: psock_send request failed: %d\n", ret);
     }
 
-  /* Send the call message
-   *
-   * On success, psock_send returns the number of bytes sent;
-   * On failure, it returns a negated errno value.
-   */
-
-  ret = psock_send(&rpc->rc_so, call, reqlen, 0);
   if (ret < 0)
     {
-      ferr("ERROR: psock_send request failed: %d\n", ret);
       return ret;
     }