Merge tag 'nfs-for-4.6-1' of git://git.linux-nfs.org/projects/trondmy/linux-nfs

Pull NFS client updates from Trond Myklebust:
 "Highlights include:

  Features:
   - Add support for multiple NFSv4.1 callbacks in flight
   - Initial patchset for RPC multipath support
   - Adapt RPC/RDMA to use the new completion queue API

  Bugfixes and cleanups:
   - nfs4: nfs4_ff_layout_prepare_ds should return NULL if connection failed
   - Cleanups to remove nfs_inode_dio_wait and nfs4_file_fsync
   - Fix RPC/RDMA credit accounting
   - Properly handle RDMA_ERROR replies
   - xprtrdma: Do not wait if ib_post_send() fails
   - xprtrdma: Segment head and tail XDR buffers on page boundaries
   - xprtrdma cleanups for dprintk, physical_op_map and unused macros"

* tag 'nfs-for-4.6-1' of git://git.linux-nfs.org/projects/trondmy/linux-nfs: (35 commits)
  nfs/blocklayout: make sure making a aligned read request
  nfs4: nfs4_ff_layout_prepare_ds should return NULL if connection failed
  nfs: remove nfs_inode_dio_wait
  nfs: remove nfs4_file_fsync
  xprtrdma: Use new CQ API for RPC-over-RDMA client send CQs
  xprtrdma: Use an anonymous union in struct rpcrdma_mw
  xprtrdma: Use new CQ API for RPC-over-RDMA client receive CQs
  xprtrdma: Serialize credit accounting again
  xprtrdma: Properly handle RDMA_ERROR replies
  rpcrdma: Add RPCRDMA_HDRLEN_ERR
  xprtrdma: Do not wait if ib_post_send() fails
  xprtrdma: Segment head and tail XDR buffers on page boundaries
  xprtrdma: Clean up dprintk format string containing a newline
  xprtrdma: Clean up physical_op_map()
  xprtrdma: Clean up unused RPCRDMA_INLINE_PAD_THRESH macro
  NFS add callback_ops to nfs4_proc_bind_conn_to_session_callback
  pnfs/NFSv4.1: Add multipath capabilities to pNFS flexfiles servers over NFSv3
  SUNRPC: Allow addition of new transports to a struct rpc_clnt
  NFSv4.1: nfs4_proc_bind_conn_to_session must iterate over all connections
  SUNRPC: Make NFS swap work with multipath
  ...

6 files changed, 120 insertions, 35 deletions

diff --git a/include/linux/sunrpc/clnt.h b/include/linux/sunrpc/clnt.h
index 131032f15cc1..9a7ddbaf116e 100644
--- a/include/linux/sunrpc/clnt.h
+++ b/include/linux/sunrpc/clnt.h
@@ -25,6 +25,7 @@
 #include <asm/signal.h>
 #include <linux/path.h>
 #include <net/ipv6.h>
+#include <linux/sunrpc/xprtmultipath.h>
 
 struct rpc_inode;
 
@@ -67,6 +68,7 @@ struct rpc_clnt {
 #if IS_ENABLED(CONFIG_SUNRPC_DEBUG)
 	struct dentry		*cl_debugfs;	/* debugfs directory */
 #endif
+	struct rpc_xprt_iter	cl_xpi;
 };
 
 /*
@@ -139,7 +141,6 @@ struct rpc_clnt *rpc_create_xprt(struct rpc_create_args *args,
 					struct rpc_xprt *xprt);
 struct rpc_clnt	*rpc_bind_new_program(struct rpc_clnt *,
 				const struct rpc_program *, u32);
-void rpc_task_reset_client(struct rpc_task *task, struct rpc_clnt *clnt);
 struct rpc_clnt *rpc_clone_client(struct rpc_clnt *);
 struct rpc_clnt *rpc_clone_client_set_auth(struct rpc_clnt *,
 				rpc_authflavor_t);
@@ -181,6 +182,21 @@ size_t		rpc_peeraddr(struct rpc_clnt *, struct sockaddr *, size_t);
 const char	*rpc_peeraddr2str(struct rpc_clnt *, enum rpc_display_format_t);
 int		rpc_localaddr(struct rpc_clnt *, struct sockaddr *, size_t);
 
+int 		rpc_clnt_iterate_for_each_xprt(struct rpc_clnt *clnt,
+			int (*fn)(struct rpc_clnt *, struct rpc_xprt *, void *),
+			void *data);
+
+int 		rpc_clnt_test_and_add_xprt(struct rpc_clnt *clnt,
+			struct rpc_xprt_switch *xps,
+			struct rpc_xprt *xprt,
+			void *dummy);
+int		rpc_clnt_add_xprt(struct rpc_clnt *, struct xprt_create *,
+			int (*setup)(struct rpc_clnt *,
+				struct rpc_xprt_switch *,
+				struct rpc_xprt *,
+				void *),
+			void *data);
+
 const char *rpc_proc_name(const struct rpc_task *task);
 #endif /* __KERNEL__ */
 #endif /* _LINUX_SUNRPC_CLNT_H */
diff --git a/include/linux/sunrpc/rpc_rdma.h b/include/linux/sunrpc/rpc_rdma.h
index f33c5a4d6fe4..3b1ff38f0c37 100644
--- a/include/linux/sunrpc/rpc_rdma.h
+++ b/include/linux/sunrpc/rpc_rdma.h
@@ -93,6 +93,12 @@ struct rpcrdma_msg {
 			__be32 rm_pempty[3];	/* 3 empty chunk lists */
 		} rm_padded;
 
+		struct {
+			__be32 rm_err;
+			__be32 rm_vers_low;
+			__be32 rm_vers_high;
+		} rm_error;
+
 		__be32 rm_chunks[0];	/* read, write and reply chunks */
 
 	} rm_body;
@@ -102,17 +108,13 @@ struct rpcrdma_msg {
  * Smallest RPC/RDMA header: rm_xid through rm_type, then rm_nochunks
  */
 #define RPCRDMA_HDRLEN_MIN	(sizeof(__be32) * 7)
+#define RPCRDMA_HDRLEN_ERR	(sizeof(__be32) * 5)
 
 enum rpcrdma_errcode {
 	ERR_VERS = 1,
 	ERR_CHUNK = 2
 };
 
-struct rpcrdma_err_vers {
-	uint32_t rdma_vers_low;	/* Version range supported by peer */
-	uint32_t rdma_vers_high;
-};
-
 enum rpcrdma_proc {
 	RDMA_MSG = 0,		/* An RPC call or reply msg */
 	RDMA_NOMSG = 1,		/* An RPC call or reply msg - separate body */
diff --git a/include/linux/sunrpc/sched.h b/include/linux/sunrpc/sched.h
index d703f0ef37d8..05a1809c44d9 100644
--- a/include/linux/sunrpc/sched.h
+++ b/include/linux/sunrpc/sched.h
@@ -42,40 +42,43 @@ struct rpc_wait {
  */
 struct rpc_task {
 	atomic_t		tk_count;	/* Reference count */
+	int			tk_status;	/* result of last operation */
 	struct list_head	tk_task;	/* global list of tasks */
-	struct rpc_clnt *	tk_client;	/* RPC client */
-	struct rpc_rqst *	tk_rqstp;	/* RPC request */
-
-	/*
-	 * RPC call state
-	 */
-	struct rpc_message	tk_msg;		/* RPC call info */
 
 	/*
 	 * callback	to be executed after waking up
 	 * action	next procedure for async tasks
-	 * tk_ops	caller callbacks
 	 */
 	void			(*tk_callback)(struct rpc_task *);
 	void			(*tk_action)(struct rpc_task *);
-	const struct rpc_call_ops *tk_ops;
-	void *			tk_calldata;
 
 	unsigned long		tk_timeout;	/* timeout for rpc_sleep() */
 	unsigned long		tk_runstate;	/* Task run status */
-	struct workqueue_struct	*tk_workqueue;	/* Normally rpciod, but could
-						 * be any workqueue
-						 */
+
 	struct rpc_wait_queue 	*tk_waitqueue;	/* RPC wait queue we're on */
 	union {
 		struct work_struct	tk_work;	/* Async task work queue */
 		struct rpc_wait		tk_wait;	/* RPC wait */
 	} u;
 
+	/*
+	 * RPC call state
+	 */
+	struct rpc_message	tk_msg;		/* RPC call info */
+	void *			tk_calldata;	/* Caller private data */
+	const struct rpc_call_ops *tk_ops;	/* Caller callbacks */
+
+	struct rpc_clnt *	tk_client;	/* RPC client */
+	struct rpc_xprt *	tk_xprt;	/* Transport */
+
+	struct rpc_rqst *	tk_rqstp;	/* RPC request */
+
+	struct workqueue_struct	*tk_workqueue;	/* Normally rpciod, but could
+						 * be any workqueue
+						 */
 	ktime_t			tk_start;	/* RPC task init timestamp */
 
 	pid_t			tk_owner;	/* Process id for batching tasks */
-	int			tk_status;	/* result of last operation */
 	unsigned short		tk_flags;	/* misc flags */
 	unsigned short		tk_timeouts;	/* maj timeouts */
 
@@ -100,6 +103,7 @@ struct rpc_call_ops {
 struct rpc_task_setup {
 	struct rpc_task *task;
 	struct rpc_clnt *rpc_client;
+	struct rpc_xprt *rpc_xprt;
 	const struct rpc_message *rpc_message;
 	const struct rpc_call_ops *callback_ops;
 	void *callback_data;
diff --git a/include/linux/sunrpc/xprt.h b/include/linux/sunrpc/xprt.h
index 69ef5b3ab038..fb0d212e0d3a 100644
--- a/include/linux/sunrpc/xprt.h
+++ b/include/linux/sunrpc/xprt.h
@@ -13,6 +13,7 @@
 #include <linux/socket.h>
 #include <linux/in.h>
 #include <linux/ktime.h>
+#include <linux/kref.h>
 #include <linux/sunrpc/sched.h>
 #include <linux/sunrpc/xdr.h>
 #include <linux/sunrpc/msg_prot.h>
@@ -166,7 +167,7 @@ enum xprt_transports {
 };
 
 struct rpc_xprt {
-	atomic_t		count;		/* Reference count */
+	struct kref		kref;		/* Reference count */
 	struct rpc_xprt_ops *	ops;		/* transport methods */
 
 	const struct rpc_timeout *timeout;	/* timeout parms */
@@ -197,6 +198,11 @@ struct rpc_xprt {
 	unsigned int		bind_index;	/* bind function index */
 
 	/*
+	 * Multipath
+	 */
+	struct list_head	xprt_switch;
+
+	/*
 	 * Connection of transports
 	 */
 	unsigned long		bind_timeout,
@@ -256,6 +262,7 @@ struct rpc_xprt {
 	struct dentry		*debugfs;		/* debugfs directory */
 	atomic_t		inject_disconnect;
 #endif
+	struct rcu_head		rcu;
 };
 
 #if defined(CONFIG_SUNRPC_BACKCHANNEL)
@@ -318,24 +325,13 @@ int			xprt_adjust_timeout(struct rpc_rqst *req);
 void			xprt_release_xprt(struct rpc_xprt *xprt, struct rpc_task *task);
 void			xprt_release_xprt_cong(struct rpc_xprt *xprt, struct rpc_task *task);
 void			xprt_release(struct rpc_task *task);
+struct rpc_xprt *	xprt_get(struct rpc_xprt *xprt);
 void			xprt_put(struct rpc_xprt *xprt);
 struct rpc_xprt *	xprt_alloc(struct net *net, size_t size,
 				unsigned int num_prealloc,
 				unsigned int max_req);
 void			xprt_free(struct rpc_xprt *);
 
-/**
- * xprt_get - return a reference to an RPC transport.
- * @xprt: pointer to the transport
- *
- */
-static inline struct rpc_xprt *xprt_get(struct rpc_xprt *xprt)
-{
-	if (atomic_inc_not_zero(&xprt->count))
-		return xprt;
-	return NULL;
-}
-
 static inline __be32 *xprt_skip_transport_header(struct rpc_xprt *xprt, __be32 *p)
 {
 	return p + xprt->tsh_size;
diff --git a/include/linux/sunrpc/xprtmultipath.h b/include/linux/sunrpc/xprtmultipath.h
new file mode 100644
index 000000000000..5a9acffa41be
--- /dev/null
+++ b/include/linux/sunrpc/xprtmultipath.h
@@ -0,0 +1,69 @@
+/*
+ * RPC client multipathing definitions
+ *
+ * Copyright (c) 2015, 2016, Primary Data, Inc. All rights reserved.
+ *
+ * Trond Myklebust <trond.myklebust@primarydata.com>
+ */
+#ifndef _NET_SUNRPC_XPRTMULTIPATH_H
+#define _NET_SUNRPC_XPRTMULTIPATH_H
+
+struct rpc_xprt_iter_ops;
+struct rpc_xprt_switch {
+	spinlock_t		xps_lock;
+	struct kref		xps_kref;
+
+	unsigned int		xps_nxprts;
+	struct list_head	xps_xprt_list;
+
+	struct net *		xps_net;
+
+	const struct rpc_xprt_iter_ops *xps_iter_ops;
+
+	struct rcu_head		xps_rcu;
+};
+
+struct rpc_xprt_iter {
+	struct rpc_xprt_switch __rcu *xpi_xpswitch;
+	struct rpc_xprt *	xpi_cursor;
+
+	const struct rpc_xprt_iter_ops *xpi_ops;
+};
+
+
+struct rpc_xprt_iter_ops {
+	void (*xpi_rewind)(struct rpc_xprt_iter *);
+	struct rpc_xprt *(*xpi_xprt)(struct rpc_xprt_iter *);
+	struct rpc_xprt *(*xpi_next)(struct rpc_xprt_iter *);
+};
+
+extern struct rpc_xprt_switch *xprt_switch_alloc(struct rpc_xprt *xprt,
+		gfp_t gfp_flags);
+
+extern struct rpc_xprt_switch *xprt_switch_get(struct rpc_xprt_switch *xps);
+extern void xprt_switch_put(struct rpc_xprt_switch *xps);
+
+extern void rpc_xprt_switch_set_roundrobin(struct rpc_xprt_switch *xps);
+
+extern void rpc_xprt_switch_add_xprt(struct rpc_xprt_switch *xps,
+		struct rpc_xprt *xprt);
+extern void rpc_xprt_switch_remove_xprt(struct rpc_xprt_switch *xps,
+		struct rpc_xprt *xprt);
+
+extern void xprt_iter_init(struct rpc_xprt_iter *xpi,
+		struct rpc_xprt_switch *xps);
+
+extern void xprt_iter_init_listall(struct rpc_xprt_iter *xpi,
+		struct rpc_xprt_switch *xps);
+
+extern void xprt_iter_destroy(struct rpc_xprt_iter *xpi);
+
+extern struct rpc_xprt_switch *xprt_iter_xchg_switch(
+		struct rpc_xprt_iter *xpi,
+		struct rpc_xprt_switch *newswitch);
+
+extern struct rpc_xprt *xprt_iter_xprt(struct rpc_xprt_iter *xpi);
+extern struct rpc_xprt *xprt_iter_get_xprt(struct rpc_xprt_iter *xpi);
+extern struct rpc_xprt *xprt_iter_get_next(struct rpc_xprt_iter *xpi);
+
+#endif
diff --git a/include/linux/sunrpc/xprtrdma.h b/include/linux/sunrpc/xprtrdma.h
index b7b279b54504..767190b01363 100644
--- a/include/linux/sunrpc/xprtrdma.h
+++ b/include/linux/sunrpc/xprtrdma.h
@@ -54,8 +54,6 @@
 
 #define RPCRDMA_DEF_INLINE  (1024)	/* default inline max */
 
-#define RPCRDMA_INLINE_PAD_THRESH  (512)/* payload threshold to pad (bytes) */
-
 /* Memory registration strategies, by number.
  * This is part of a kernel / user space API. Do not remove. */
 enum rpcrdma_memreg {