Merge tag 'nfs-for-3.13-2' of git://git.linux-nfs.org/projects/trondmy/linux-nfs

Pull NFS client bugfixes:
 - Stable fix for data corruption when retransmitting O_DIRECT writes
 - Stable fix for a deep recursion/stack overflow bug in rpc_release_client
 - Stable fix for infinite looping when mounting a NFSv4.x volume
 - Fix a typo in the nfs mount option parser
 - Allow pNFS layouts to be compiled into the kernel when NFSv4.1 is

* tag 'nfs-for-3.13-2' of git://git.linux-nfs.org/projects/trondmy/linux-nfs:
  nfs: fix pnfs Kconfig defaults
  NFS: correctly report misuse of "migration" mount option.
  nfs: don't retry detect_trunking with RPC_AUTH_UNIX more than once
  SUNRPC: Avoid deep recursion in rpc_release_client
  SUNRPC: Fix a data corruption issue when retransmitting RPC calls

2 files changed, 38 insertions, 19 deletions

diff --git a/net/sunrpc/clnt.c b/net/sunrpc/clnt.c
index dab09dac8fc..f09b7db2c49 100644
--- a/net/sunrpc/clnt.c
+++ b/net/sunrpc/clnt.c
@@ -750,14 +750,16 @@ EXPORT_SYMBOL_GPL(rpc_shutdown_client);
 /*
  * Free an RPC client
  */
-static void
+static struct rpc_clnt *
 rpc_free_client(struct rpc_clnt *clnt)
 {
+	struct rpc_clnt *parent = NULL;
+
 	dprintk_rcu("RPC:       destroying %s client for %s\n",
 			clnt->cl_program->name,
 			rcu_dereference(clnt->cl_xprt)->servername);
 	if (clnt->cl_parent != clnt)
-		rpc_release_client(clnt->cl_parent);
+		parent = clnt->cl_parent;
 	rpc_clnt_remove_pipedir(clnt);
 	rpc_unregister_client(clnt);
 	rpc_free_iostats(clnt->cl_metrics);
@@ -766,18 +768,17 @@ rpc_free_client(struct rpc_clnt *clnt)
 	rpciod_down();
 	rpc_free_clid(clnt);
 	kfree(clnt);
+	return parent;
 }
 
 /*
  * Free an RPC client
  */
-static void
+static struct rpc_clnt * 
 rpc_free_auth(struct rpc_clnt *clnt)
 {
-	if (clnt->cl_auth == NULL) {
-		rpc_free_client(clnt);
-		return;
-	}
+	if (clnt->cl_auth == NULL)
+		return rpc_free_client(clnt);
 
 	/*
 	 * Note: RPCSEC_GSS may need to send NULL RPC calls in order to
@@ -788,7 +789,8 @@ rpc_free_auth(struct rpc_clnt *clnt)
 	rpcauth_release(clnt->cl_auth);
 	clnt->cl_auth = NULL;
 	if (atomic_dec_and_test(&clnt->cl_count))
-		rpc_free_client(clnt);
+		return rpc_free_client(clnt);
+	return NULL;
 }
 
 /*
@@ -799,10 +801,13 @@ rpc_release_client(struct rpc_clnt *clnt)
 {
 	dprintk("RPC:       rpc_release_client(%p)\n", clnt);
 
-	if (list_empty(&clnt->cl_tasks))
-		wake_up(&destroy_wait);
-	if (atomic_dec_and_test(&clnt->cl_count))
-		rpc_free_auth(clnt);
+	do {
+		if (list_empty(&clnt->cl_tasks))
+			wake_up(&destroy_wait);
+		if (!atomic_dec_and_test(&clnt->cl_count))
+			break;
+		clnt = rpc_free_auth(clnt);
+	} while (clnt != NULL);
 }
 EXPORT_SYMBOL_GPL(rpc_release_client);
 
diff --git a/net/sunrpc/xprtsock.c b/net/sunrpc/xprtsock.c
index 17c88928b7d..dd9d295813c 100644
--- a/net/sunrpc/xprtsock.c
+++ b/net/sunrpc/xprtsock.c
@@ -393,8 +393,10 @@ static int xs_send_kvec(struct socket *sock, struct sockaddr *addr, int addrlen,
 	return kernel_sendmsg(sock, &msg, NULL, 0, 0);
 }
 
-static int xs_send_pagedata(struct socket *sock, struct xdr_buf *xdr, unsigned int base, int more)
+static int xs_send_pagedata(struct socket *sock, struct xdr_buf *xdr, unsigned int base, int more, bool zerocopy)
 {
+	ssize_t (*do_sendpage)(struct socket *sock, struct page *page,
+			int offset, size_t size, int flags);
 	struct page **ppage;
 	unsigned int remainder;
 	int err, sent = 0;
@@ -403,6 +405,9 @@ static int xs_send_pagedata(struct socket *sock, struct xdr_buf *xdr, unsigned i
 	base += xdr->page_base;
 	ppage = xdr->pages + (base >> PAGE_SHIFT);
 	base &= ~PAGE_MASK;
+	do_sendpage = sock->ops->sendpage;
+	if (!zerocopy)
+		do_sendpage = sock_no_sendpage;
 	for(;;) {
 		unsigned int len = min_t(unsigned int, PAGE_SIZE - base, remainder);
 		int flags = XS_SENDMSG_FLAGS;
@@ -410,7 +415,7 @@ 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, base, len, flags);
+		err = do_sendpage(sock, *ppage, base, len, flags);
 		if (remainder == 0 || err != len)
 			break;
 		sent += err;
@@ -431,9 +436,10 @@ static int xs_send_pagedata(struct socket *sock, struct xdr_buf *xdr, unsigned i
  * @addrlen: UDP only -- length of destination address
  * @xdr: buffer containing this request
  * @base: starting position in the buffer
+ * @zerocopy: true if it is safe to use sendpage()
  *
  */
-static int xs_sendpages(struct socket *sock, struct sockaddr *addr, int addrlen, struct xdr_buf *xdr, unsigned int base)
+static int xs_sendpages(struct socket *sock, struct sockaddr *addr, int addrlen, struct xdr_buf *xdr, unsigned int base, bool zerocopy)
 {
 	unsigned int remainder = xdr->len - base;
 	int err, sent = 0;
@@ -461,7 +467,7 @@ static int xs_sendpages(struct socket *sock, struct sockaddr *addr, int addrlen,
 	if (base < xdr->page_len) {
 		unsigned int len = xdr->page_len - base;
 		remainder -= len;
-		err = xs_send_pagedata(sock, xdr, base, remainder != 0);
+		err = xs_send_pagedata(sock, xdr, base, remainder != 0, zerocopy);
 		if (remainder == 0 || err != len)
 			goto out;
 		sent += err;
@@ -564,7 +570,7 @@ static int xs_local_send_request(struct rpc_task *task)
 			req->rq_svec->iov_base, req->rq_svec->iov_len);
 
 	status = xs_sendpages(transport->sock, NULL, 0,
-						xdr, req->rq_bytes_sent);
+						xdr, req->rq_bytes_sent, true);
 	dprintk("RPC:       %s(%u) = %d\n",
 			__func__, xdr->len - req->rq_bytes_sent, status);
 	if (likely(status >= 0)) {
@@ -620,7 +626,7 @@ static int xs_udp_send_request(struct rpc_task *task)
 	status = xs_sendpages(transport->sock,
 			      xs_addr(xprt),
 			      xprt->addrlen, xdr,
-			      req->rq_bytes_sent);
+			      req->rq_bytes_sent, true);
 
 	dprintk("RPC:       xs_udp_send_request(%u) = %d\n",
 			xdr->len - req->rq_bytes_sent, status);
@@ -693,6 +699,7 @@ static int xs_tcp_send_request(struct rpc_task *task)
 	struct rpc_xprt *xprt = req->rq_xprt;
 	struct sock_xprt *transport = container_of(xprt, struct sock_xprt, xprt);
 	struct xdr_buf *xdr = &req->rq_snd_buf;
+	bool zerocopy = true;
 	int status;
 
 	xs_encode_stream_record_marker(&req->rq_snd_buf);
@@ -700,13 +707,20 @@ static int xs_tcp_send_request(struct rpc_task *task)
 	xs_pktdump("packet data:",
 				req->rq_svec->iov_base,
 				req->rq_svec->iov_len);
+	/* Don't use zero copy if this is a resend. If the RPC call
+	 * completes while the socket holds a reference to the pages,
+	 * then we may end up resending corrupted data.
+	 */
+	if (task->tk_flags & RPC_TASK_SENT)
+		zerocopy = false;
 
 	/* Continue transmitting the packet/record. We must be careful
 	 * to cope with writespace callbacks arriving _after_ we have
 	 * called sendmsg(). */
 	while (1) {
 		status = xs_sendpages(transport->sock,
-					NULL, 0, xdr, req->rq_bytes_sent);
+					NULL, 0, xdr, req->rq_bytes_sent,
+					zerocopy);
 
 		dprintk("RPC:       xs_tcp_send_request(%u) = %d\n",
 				xdr->len - req->rq_bytes_sent, status);