From mboxrd@z Thu Jan 1 00:00:00 1970 From: Ding Tianhong Subject: [RFC] Is it a bug for nfs on udp6 mode or kernel? Date: Wed, 13 Apr 2016 19:28:41 +0800 Message-ID: <570E2D69.7080102@huawei.com> Mime-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: QUOTED-PRINTABLE To: , , Netdev , "linux-kernel@vger.kernel.org" , , , Return-path: Sender: linux-kernel-owner@vger.kernel.org List-Id: netdev.vger.kernel.org Hi everyone: I have met this problem when I try to test udp6 for nfs connection, my = environment is: Server: kernel: 4.1.15 IP:xxxx::36/64 MTU:1500 Setting: /etc/exports:/home/nfs *(rw,sync,no_subtree_check,no_root_squa= sh) Client: kernel: 4.1.18 IP:xxxx::90/64 MTU:1500 command: mount -t nfs -o vers=3D3,proto=3Dudp6,rsize=3D4096,wsize=3D409= 6 [xxxx::36]:/home/nfs /home/tmp I check the nfs parameter configuration, it looks fine and could work w= ell for proto=3Dtcp6. Then I have mount correctly and try to run the command "ls", it hang. When I use the rsize=3D1024 and wsize=3D1024 to mount, the problem disa= ppeared, so I guess it is the problem for GSO or GRO for UDP=E3=80=82 Then I try to debug the problem, first I tcpdump the package from cline= to server, and found that the client have send readdirplus message to server correctly, and then = the Server send a 4k package to client(the big package will frag to 4 package by GSO), till now it l= ooks fine, and the Client Nic could receive the 4 skb then send to upper stack to ipv6 and udp, I found the= incoming 4 package has been merged to one and send to upper stack just like sunrpc, but I try to open the = rpc_debug, it looks that the rpc could not receive message. I built a simple demo to test the udp stack, use the client socket to s= end big package to server socket, it work well, so I think the udp is fine, maybe the bug is in sunrpc. The test is very simple, does any body met the same problem like me, th= anks for any suggestion. Ding=20