Return-Path: Received: from smtp02.citrix.com ([66.165.176.63]:4118 "EHLO SMTP02.CITRIX.COM" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754411Ab1GVNSM (ORCPT ); Fri, 22 Jul 2011 09:18:12 -0400 From: Ian Campbell To: netdev@vger.kernel.org, linux-nfs@vger.kernel.org CC: Ian Campbell , Trond Myklebust , "David S. Miller" , Neil Brown , "J. Bruce Fields" Subject: [PATCH 13/13] sunrpc: use SKB fragment destructors to delay completion until page is released by network stack. Date: Fri, 22 Jul 2011 14:17:33 +0100 Message-ID: <1311340653-19336-13-git-send-email-ian.campbell@citrix.com> In-Reply-To: <1311340095.12772.57.camel@zakaz.uk.xensource.com> References: <1311340095.12772.57.camel@zakaz.uk.xensource.com> Content-Type: text/plain Sender: linux-nfs-owner@vger.kernel.org List-ID: MIME-Version: 1.0 This prevents an issue where an ACK is delayed, a retransmit is queued (either at the RPC or TCP level) and the ACK arrives before the retransmission hits the wire. If this happens to an NFS WRITE RPC then the write() system call completes and the userspace process can continue, potentially modifying data referenced by the retransmission before the retransmission occurs. Signed-off-by: Ian Campbell Cc: Trond Myklebust Cc: "David S. Miller" Cc: Neil Brown Cc: "J. Bruce Fields" Cc: linux-nfs@vger.kernel.org Cc: netdev@vger.kernel.org [since v1: Push down from NFS layer into RPM layer ] --- include/linux/sunrpc/xdr.h | 2 ++ include/linux/sunrpc/xprt.h | 5 ++++- net/sunrpc/clnt.c | 27 ++++++++++++++++++++++----- net/sunrpc/svcsock.c | 2 +- net/sunrpc/xprt.c | 13 +++++++++++++ net/sunrpc/xprtsock.c | 2 +- 6 files changed, 43 insertions(+), 8 deletions(-) diff --git a/include/linux/sunrpc/xdr.h b/include/linux/sunrpc/xdr.h index a20970e..172f81e 100644 --- a/include/linux/sunrpc/xdr.h +++ b/include/linux/sunrpc/xdr.h @@ -16,6 +16,7 @@ #include #include #include +#include /* * Buffer adjustment @@ -57,6 +58,7 @@ struct xdr_buf { tail[1]; /* Appended after page data */ struct page ** pages; /* Array of contiguous pages */ + struct skb_frag_destructor *destructor; unsigned int page_base, /* Start of page data */ page_len, /* Length of page data */ flags; /* Flags for data disposition */ diff --git a/include/linux/sunrpc/xprt.h b/include/linux/sunrpc/xprt.h index 81cce3b..0de6bc3 100644 --- a/include/linux/sunrpc/xprt.h +++ b/include/linux/sunrpc/xprt.h @@ -91,7 +91,10 @@ struct rpc_rqst { /* A cookie used to track the state of the transport connection */ - + struct skb_frag_destructor destructor; /* SKB paged fragment + * destructor for + * transmitted pages*/ + /* * Partial send handling */ diff --git a/net/sunrpc/clnt.c b/net/sunrpc/clnt.c index 8c91415..1145a19 100644 --- a/net/sunrpc/clnt.c +++ b/net/sunrpc/clnt.c @@ -61,6 +61,7 @@ static void call_reserve(struct rpc_task *task); static void call_reserveresult(struct rpc_task *task); static void call_allocate(struct rpc_task *task); static void call_decode(struct rpc_task *task); +static void call_complete(struct rpc_task *task); static void call_bind(struct rpc_task *task); static void call_bind_status(struct rpc_task *task); static void call_transmit(struct rpc_task *task); @@ -1114,6 +1115,8 @@ rpc_xdr_encode(struct rpc_task *task) (char *)req->rq_buffer + req->rq_callsize, req->rq_rcvsize); + req->rq_snd_buf.destructor = &req->destructor; + p = rpc_encode_header(task); if (p == NULL) { printk(KERN_INFO "RPC: couldn't encode RPC header, exit EIO\n"); @@ -1277,6 +1280,7 @@ call_connect_status(struct rpc_task *task) static void call_transmit(struct rpc_task *task) { + struct rpc_rqst *req = task->tk_rqstp; dprint_status(task); task->tk_action = call_status; @@ -1310,8 +1314,8 @@ call_transmit(struct rpc_task *task) call_transmit_status(task); if (rpc_reply_expected(task)) return; - task->tk_action = rpc_exit_task; - rpc_wake_up_queued_task(&task->tk_xprt->pending, task); + task->tk_action = call_complete; + skb_frag_destructor_unref(&req->destructor); } /* @@ -1384,7 +1388,8 @@ call_bc_transmit(struct rpc_task *task) return; } - task->tk_action = rpc_exit_task; + task->tk_action = call_complete; + skb_frag_destructor_unref(&req->destructor); if (task->tk_status < 0) { printk(KERN_NOTICE "RPC: Could not send backchannel reply " "error: %d\n", task->tk_status); @@ -1424,7 +1429,6 @@ call_bc_transmit(struct rpc_task *task) "error: %d\n", task->tk_status); break; } - rpc_wake_up_queued_task(&req->rq_xprt->pending, task); } #endif /* CONFIG_NFS_V4_1 */ @@ -1591,12 +1595,14 @@ call_decode(struct rpc_task *task) return; } - task->tk_action = rpc_exit_task; + task->tk_action = call_complete; if (decode) { task->tk_status = rpcauth_unwrap_resp(task, decode, req, p, task->tk_msg.rpc_resp); } + rpc_sleep_on(&req->rq_xprt->pending, task, NULL); + skb_frag_destructor_unref(&req->destructor); dprintk("RPC: %5u call_decode result %d\n", task->tk_pid, task->tk_status); return; @@ -1611,6 +1617,17 @@ out_retry: } } +/* + * 8. Wait for pages to be released by the network stack. + */ +static void +call_complete(struct rpc_task *task) +{ + struct rpc_rqst *req = task->tk_rqstp; + dprintk("RPC: %5u call_complete result %d\n", task->tk_pid, task->tk_status); + task->tk_action = rpc_exit_task; +} + static __be32 * rpc_encode_header(struct rpc_task *task) { diff --git a/net/sunrpc/svcsock.c b/net/sunrpc/svcsock.c index a80b1d3..40c2420 100644 --- a/net/sunrpc/svcsock.c +++ b/net/sunrpc/svcsock.c @@ -194,7 +194,7 @@ int svc_send_common(struct socket *sock, struct xdr_buf *xdr, while (pglen > 0) { if (slen == size) flags = 0; - result = kernel_sendpage(sock, *ppage, NULL, base, size, flags); + result = kernel_sendpage(sock, *ppage, xdr->destructor, base, size, flags); if (result > 0) len += result; if (result != size) diff --git a/net/sunrpc/xprt.c b/net/sunrpc/xprt.c index ce5eb68..62f52a3 100644 --- a/net/sunrpc/xprt.c +++ b/net/sunrpc/xprt.c @@ -1017,6 +1017,16 @@ static inline void xprt_init_xid(struct rpc_xprt *xprt) xprt->xid = net_random(); } +static int xprt_complete_skb_pages(void *calldata) +{ + struct rpc_task *task = calldata; + struct rpc_rqst *req = task->tk_rqstp; + + dprintk("RPC: %5u completing skb pages\n", task->tk_pid); + rpc_wake_up_queued_task(&req->rq_xprt->pending, task); + return 0; +} + static void xprt_request_init(struct rpc_task *task, struct rpc_xprt *xprt) { struct rpc_rqst *req = task->tk_rqstp; @@ -1028,6 +1038,9 @@ static void xprt_request_init(struct rpc_task *task, struct rpc_xprt *xprt) req->rq_xid = xprt_alloc_xid(xprt); req->rq_release_snd_buf = NULL; xprt_reset_majortimeo(req); + atomic_set(&req->destructor.ref, 1); + req->destructor.destroy = &xprt_complete_skb_pages; + req->destructor.data = task; dprintk("RPC: %5u reserved req %p xid %08x\n", task->tk_pid, req, ntohl(req->rq_xid)); } diff --git a/net/sunrpc/xprtsock.c b/net/sunrpc/xprtsock.c index d027621..ca1643b 100644 --- a/net/sunrpc/xprtsock.c +++ b/net/sunrpc/xprtsock.c @@ -397,7 +397,7 @@ static int xs_send_pagedata(struct socket *sock, struct xdr_buf *xdr, unsigned i remainder -= len; if (remainder != 0 || more) flags |= MSG_MORE; - err = sock->ops->sendpage(sock, *ppage, NULL, base, len, flags); + err = sock->ops->sendpage(sock, *ppage, xdr->destructor, base, len, flags); if (remainder == 0 || err != len) break; sent += err; -- 1.7.2.5