On 01/10/2014 01:27 AM, Trond Myklebust wrote: > > On Jan 9, 2014, at 11:26, Dr Fields James Bruce <bfields@xxxxxxxxxxxx> wrote: > >> On Thu, Jan 09, 2014 at 06:33:10PM +0800, Kinglong Mee wrote: >>> Besides checking rpc_xprt out of xs_setup_bc_tcp, >>> increase it's reference (it's important). >> >> This sounds wrong to me: the presence of a backchannel can't prevent the >> client's connection from going away. Instead, when the connection dies, >> any associated backchannels should be immediately destroyed. > > Hi Bruce, > > The right way to deal with this is to have knfsd shut down the rpc_client > when it detects the TCP disconnection event. Yes, that's right. Knfsd has do it as you said. When getting xprt's status of XPT_CLOSE in svc_recv/svc_handle_xprt, knfsd will delete the xprt by svc_delete_xprt. In svc_delete_xprt, knfsd calls call_xpt_users to notify those users of the xprt. So, nfsd4_conn_lost will be called to free the connection. After freeing connection, nfsd4_probe_callback will update the callback for the client. And, the clp->cl_cb_client will be shutdown in nfsd4_process_cb_update. At last, all using of the xprt will be released. I have test it, that's OK. > The xprt->count shouldn’t be an issue here: > it has nothing to do with the socket connection state. The xprt of backchannel, there are two references, 1. rpc_clnt 2. svc_xprt For rpc_clnt, initialize the xprt->count in xs_setup_bc_tcp, or increase it in create_backchannel_client, and, decrease in rpc_free_client. For svc_xprt, increase it in xs_setup_bc_tcp, and decrease in svc_xprt_free. thanks, Kinglong Mee -- To unsubscribe from this list: send the line "unsubscribe linux-nfs" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
