NFS: add hooks to account for NFSERR_JUKEBOX errors

Make an inode or an nfs_server struct available in the logic that handles
JUKEBOX/DELAY type errors so the NFS client can account for them.

This patch is split out from the main nfs iostat patch to highlight minor
architectural changes required to support this statistic.

Test plan:
None.
Signed-off-by: Chuck Lever <cel@netapp.com>
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>

fs/nfs/iostat.h

@@ -103,6 +103,7 @@ enum nfs_stat_eventcounters {
 	NFSIOS_SILLYRENAME,
 	NFSIOS_SHORTREAD,
 	NFSIOS_SHORTWRITE,
+	NFSIOS_DELAY,
 	__NFSIOS_COUNTSMAX,
 };
 
@@ -116,28 +117,38 @@ struct nfs_iostats {
 	unsigned long		events[__NFSIOS_COUNTSMAX];
 } ____cacheline_aligned;
 
-static inline void nfs_inc_stats(struct inode *inode, enum nfs_stat_eventcounters stat)
+static inline void nfs_inc_server_stats(struct nfs_server *server, enum nfs_stat_eventcounters stat)
 {
 	struct nfs_iostats *iostats;
 	int cpu;
 
 	cpu = get_cpu();
-	iostats = per_cpu_ptr(NFS_SERVER(inode)->io_stats, cpu);
+	iostats = per_cpu_ptr(server->io_stats, cpu);
 	iostats->events[stat] ++;
 	put_cpu_no_resched();
 }
 
-static inline void nfs_add_stats(struct inode *inode, enum nfs_stat_bytecounters stat, unsigned long addend)
+static inline void nfs_inc_stats(struct inode *inode, enum nfs_stat_eventcounters stat)
+{
+	nfs_inc_server_stats(NFS_SERVER(inode), stat);
+}
+
+static inline void nfs_add_server_stats(struct nfs_server *server, enum nfs_stat_bytecounters stat, unsigned long addend)
 {
 	struct nfs_iostats *iostats;
 	int cpu;
 
 	cpu = get_cpu();
-	iostats = per_cpu_ptr(NFS_SERVER(inode)->io_stats, cpu);
+	iostats = per_cpu_ptr(server->io_stats, cpu);
 	iostats->bytes[stat] += addend;
 	put_cpu_no_resched();
 }
 
+static inline void nfs_add_stats(struct inode *inode, enum nfs_stat_bytecounters stat, unsigned long addend)
+{
+	nfs_add_server_stats(NFS_SERVER(inode), stat, addend);
+}
+
 static inline struct nfs_iostats *nfs_alloc_iostats(void)
 {
 	return alloc_percpu(struct nfs_iostats);

fs/nfs/nfs3proc.c

@@ -19,6 +19,8 @@
 #include <linux/smp_lock.h>
 #include <linux/nfs_mount.h>
 
+#include "iostat.h"
+
 #define NFSDBG_FACILITY		NFSDBG_PROC
 
 extern struct rpc_procinfo nfs3_procedures[];
@@ -58,10 +60,11 @@ nfs3_rpc_call_wrapper(struct rpc_clnt *clnt, u32 proc, void *argp, void *resp, i
 		nfs3_rpc_wrapper(clnt, msg, flags)
 
 static int
-nfs3_async_handle_jukebox(struct rpc_task *task)
+nfs3_async_handle_jukebox(struct rpc_task *task, struct inode *inode)
 {
 	if (task->tk_status != -EJUKEBOX)
 		return 0;
+	nfs_inc_stats(inode, NFSIOS_DELAY);
 	task->tk_status = 0;
 	rpc_restart_call(task);
 	rpc_delay(task, NFS_JUKEBOX_RETRY_TIME);
@@ -447,7 +450,7 @@ nfs3_proc_unlink_done(struct dentry *dir, struct rpc_task *task)
 	struct rpc_message *msg = &task->tk_msg;
 	struct nfs_fattr	*dir_attr;
 
-	if (nfs3_async_handle_jukebox(task))
+	if (nfs3_async_handle_jukebox(task, dir->d_inode))
 		return 1;
 	if (msg->rpc_argp) {
 		dir_attr = (struct nfs_fattr*)msg->rpc_resp;
@@ -748,7 +751,7 @@ static void nfs3_read_done(struct rpc_task *task, void *calldata)
 {
 	struct nfs_read_data *data = calldata;
 
-	if (nfs3_async_handle_jukebox(task))
+	if (nfs3_async_handle_jukebox(task, data->inode))
 		return;
 	/* Call back common NFS readpage processing */
 	if (task->tk_status >= 0)
@@ -786,7 +789,7 @@ static void nfs3_write_done(struct rpc_task *task, void *calldata)
 {
 	struct nfs_write_data *data = calldata;
 
-	if (nfs3_async_handle_jukebox(task))
+	if (nfs3_async_handle_jukebox(task, data->inode))
 		return;
 	if (task->tk_status >= 0)
 		nfs_post_op_update_inode(data->inode, data->res.fattr);
@@ -833,7 +836,7 @@ static void nfs3_commit_done(struct rpc_task *task, void *calldata)
 {
 	struct nfs_write_data *data = calldata;
 
-	if (nfs3_async_handle_jukebox(task))
+	if (nfs3_async_handle_jukebox(task, data->inode))
 		return;
 	if (task->tk_status >= 0)
 		nfs_post_op_update_inode(data->inode, data->res.fattr);

fs/nfs/nfs4proc.c

@@ -51,6 +51,7 @@
 
 #include "nfs4_fs.h"
 #include "delegation.h"
+#include "iostat.h"
 
 #define NFSDBG_FACILITY		NFSDBG_PROC
 
@@ -2755,8 +2756,10 @@ nfs4_async_handle_error(struct rpc_task *task, const struct nfs_server *server)
 				rpc_wake_up_task(task);
 			task->tk_status = 0;
 			return -EAGAIN;
-		case -NFS4ERR_GRACE:
 		case -NFS4ERR_DELAY:
+			nfs_inc_server_stats((struct nfs_server *) server,
+						NFSIOS_DELAY);
+		case -NFS4ERR_GRACE:
 			rpc_delay(task, NFS4_POLL_RETRY_MAX);
 			task->tk_status = 0;
 			return -EAGAIN;