NFS: include filelayout DS rpc stats in mountstats

Include RPC statistics from all data servers in /proc/self/mountstats for pNFS
filelayout mounts.

Signed-off-by: Weston Andros Adamson <[e-mail]>
Signed-off-by: Trond Myklebust <[e-mail]>

fs/nfs/nfs4filelayout.c

···
 #include <linux/nfs_page.h>
 #include <linux/module.h>
 
+#include <linux/sunrpc/metrics.h>
+
 #include "internal.h"
 #include "nfs4filelayout.h"
 
···
 	rdata->mds_ops->rpc_call_done(task, data);
 }
 
+static void filelayout_read_count_stats(struct rpc_task *task, void *data)
+{
+	struct nfs_read_data *rdata = (struct nfs_read_data *)data;
+
+	rpc_count_iostats(task, NFS_SERVER(rdata->inode)->client->cl_metrics);
+}
+
 static void filelayout_read_release(void *data)
 {
 	struct nfs_read_data *rdata = (struct nfs_read_data *)data;
···
 	wdata->mds_ops->rpc_call_done(task, data);
 }
 
+static void filelayout_write_count_stats(struct rpc_task *task, void *data)
+{
+	struct nfs_write_data *wdata = (struct nfs_write_data *)data;
+
+	rpc_count_iostats(task, NFS_SERVER(wdata->inode)->client->cl_metrics);
+}
+
 static void filelayout_write_release(void *data)
 {
 	struct nfs_write_data *wdata = (struct nfs_write_data *)data;
···
 struct rpc_call_ops filelayout_read_call_ops = {
 	.rpc_call_prepare = filelayout_read_prepare,
 	.rpc_call_done = filelayout_read_call_done,
+	.rpc_count_stats = filelayout_read_count_stats,
 	.rpc_release = filelayout_read_release,
 };
 
 struct rpc_call_ops filelayout_write_call_ops = {
 	.rpc_call_prepare = filelayout_write_prepare,
 	.rpc_call_done = filelayout_write_call_done,
+	.rpc_count_stats = filelayout_write_count_stats,
 	.rpc_release = filelayout_write_release,
 };
 
 struct rpc_call_ops filelayout_commit_call_ops = {
 	.rpc_call_prepare = filelayout_write_prepare,
 	.rpc_call_done = filelayout_write_call_done,
+	.rpc_count_stats = filelayout_write_count_stats,
 	.rpc_release = filelayout_commit_release,
 };
 

include/linux/sunrpc/metrics.h

···
 #ifdef CONFIG_PROC_FS
 
 struct rpc_iostats *	rpc_alloc_iostats(struct rpc_clnt *);
-void			rpc_count_iostats(struct rpc_task *);
+void			rpc_count_iostats(const struct rpc_task *,
+					  struct rpc_iostats *);
 void			rpc_print_iostats(struct seq_file *, struct rpc_clnt *);
 void			rpc_free_iostats(struct rpc_iostats *);
 
 #else  /*  CONFIG_PROC_FS  */
 
 static inline struct rpc_iostats *rpc_alloc_iostats(struct rpc_clnt *clnt) { return NULL; }
-static inline void rpc_count_iostats(struct rpc_task *task) {}
+static inline void rpc_count_iostats(const struct rpc_task *task,
+				     struct rpc_iostats *stats) {}
 static inline void rpc_print_iostats(struct seq_file *seq, struct rpc_clnt *clnt) {}
 static inline void rpc_free_iostats(struct rpc_iostats *stats) {}
 

include/linux/sunrpc/sched.h

···
 struct rpc_call_ops {
 	void (*rpc_call_prepare)(struct rpc_task *, void *);
 	void (*rpc_call_done)(struct rpc_task *, void *);
+	void (*rpc_count_stats)(struct rpc_task *, void *);
 	void (*rpc_release)(void *);
 };
 

net/sunrpc/stats.c

···
 /**
  * rpc_count_iostats - tally up per-task stats
  * @task: completed rpc_task
+ * @stats: array of stat structures
  *
  * Relies on the caller for serialization.
  */
-void rpc_count_iostats(struct rpc_task *task)
+void rpc_count_iostats(const struct rpc_task *task, struct rpc_iostats *stats)
 {
 	struct rpc_rqst *req = task->tk_rqstp;
-	struct rpc_iostats *stats;
 	struct rpc_iostats *op_metrics;
 	ktime_t delta;
 
-	if (!task->tk_client || !task->tk_client->cl_metrics || !req)
+	if (!stats || !req)
 		return;
 
-	stats = task->tk_client->cl_metrics;
 	op_metrics = &stats[task->tk_msg.rpc_proc->p_statidx];
 
 	op_metrics->om_ops++;
···
 	delta = ktime_sub(ktime_get(), task->tk_start);
 	op_metrics->om_execute = ktime_add(op_metrics->om_execute, delta);
 }
+EXPORT_SYMBOL_GPL(rpc_count_iostats);
 
 static void _print_name(struct seq_file *seq, unsigned int op,
 			struct rpc_procinfo *procs)

net/sunrpc/xprt.c

···
 		return;
 
 	xprt = req->rq_xprt;
-	rpc_count_iostats(task);
+	if (task->tk_ops->rpc_count_stats != NULL)
+		task->tk_ops->rpc_count_stats(task, task->tk_calldata);
+	else if (task->tk_client)
+		rpc_count_iostats(task, task->tk_client->cl_metrics);
 	spin_lock_bh(&xprt->transport_lock);
 	xprt->ops->release_xprt(xprt, task);
 	if (xprt->ops->release_request)