fs/ocfs2/cluster/netdebug.c - linux - Git at Google

 // SPDX-License-Identifier: GPL-2.0-or-later
 /*
  * netdebug.c
  *
  * debug functionality for o2net
  *
  * Copyright (C) 2005, 2008 Oracle.  All rights reserved.
  */

 #ifdef CONFIG_DEBUG_FS

 #include <linux/module.h>
 #include <linux/types.h>
 #include <linux/slab.h>
 #include <linux/idr.h>
 #include <linux/kref.h>
 #include <linux/seq_file.h>
 #include <linux/debugfs.h>

 #include <linux/uaccess.h>

 #include "tcp.h"
 #include "nodemanager.h"
 #define MLOG_MASK_PREFIX ML_TCP
 #include "masklog.h"

 #include "tcp_internal.h"

 #define O2NET_DEBUG_DIR		"o2net"
 #define SC_DEBUG_NAME		"sock_containers"
 #define NST_DEBUG_NAME		"send_tracking"
 #define STATS_DEBUG_NAME	"stats"
 #define NODES_DEBUG_NAME	"connected_nodes"

 #define SHOW_SOCK_CONTAINERS	0
 #define SHOW_SOCK_STATS		1

 static struct dentry *o2net_dentry;

 static DEFINE_SPINLOCK(o2net_debug_lock);

 static LIST_HEAD(sock_containers);
 static LIST_HEAD(send_tracking);

 void o2net_debug_add_nst(struct o2net_send_tracking *nst)
 {
 	spin_lock(&o2net_debug_lock);
 	list_add(&nst->st_net_debug_item, &send_tracking);
 	spin_unlock(&o2net_debug_lock);
 }

 void o2net_debug_del_nst(struct o2net_send_tracking *nst)
 {
 	spin_lock(&o2net_debug_lock);
 	if (!list_empty(&nst->st_net_debug_item))
 		list_del_init(&nst->st_net_debug_item);
 	spin_unlock(&o2net_debug_lock);
 }

 static struct o2net_send_tracking
 			*next_nst(struct o2net_send_tracking *nst_start)
 {
 	struct o2net_send_tracking *nst, *ret = NULL;

 	assert_spin_locked(&o2net_debug_lock);

 	list_for_each_entry(nst, &nst_start->st_net_debug_item,
 			    st_net_debug_item) {
 		/* discover the head of the list */
 		if (&nst->st_net_debug_item == &send_tracking)
 			break;

 		/* use st_task to detect real nsts in the list */
 		if (nst->st_task != NULL) {
 			ret = nst;
 			break;
 		}
 	}

 	return ret;
 }

 static void *nst_seq_start(struct seq_file *seq, loff_t *pos)
 {
 	struct o2net_send_tracking *nst, *dummy_nst = seq->private;

 	spin_lock(&o2net_debug_lock);
 	nst = next_nst(dummy_nst);
 	spin_unlock(&o2net_debug_lock);

 	return nst;
 }

 static void *nst_seq_next(struct seq_file *seq, void *v, loff_t *pos)
 {
 	struct o2net_send_tracking *nst, *dummy_nst = seq->private;

 	spin_lock(&o2net_debug_lock);
 	nst = next_nst(dummy_nst);
 	list_del_init(&dummy_nst->st_net_debug_item);
 	if (nst)
 		list_add(&dummy_nst->st_net_debug_item,
 			 &nst->st_net_debug_item);
 	spin_unlock(&o2net_debug_lock);

 	return nst; /* unused, just needs to be null when done */
 }

 static int nst_seq_show(struct seq_file *seq, void *v)
 {
 	struct o2net_send_tracking *nst, *dummy_nst = seq->private;
 	ktime_t now;
 	s64 sock, send, status;

 	spin_lock(&o2net_debug_lock);
 	nst = next_nst(dummy_nst);
 	if (!nst)
 		goto out;

 	now = ktime_get();
 	sock = ktime_to_us(ktime_sub(now, nst->st_sock_time));
 	send = ktime_to_us(ktime_sub(now, nst->st_send_time));
 	status = ktime_to_us(ktime_sub(now, nst->st_status_time));

 	/* get_task_comm isn't exported.  oh well. */
 	seq_printf(seq, "%p:\n"
 		   "  pid:          %lu\n"
 		   "  tgid:         %lu\n"
 		   "  process name: %s\n"
 		   "  node:         %u\n"
 		   "  sc:           %p\n"
 		   "  message id:   %d\n"
 		   "  message type: %u\n"
 		   "  message key:  0x%08x\n"
 		   "  sock acquiry: %lld usecs ago\n"
 		   "  send start:   %lld usecs ago\n"
 		   "  wait start:   %lld usecs ago\n",
 		   nst, (unsigned long)task_pid_nr(nst->st_task),
 		   (unsigned long)nst->st_task->tgid,
 		   nst->st_task->comm, nst->st_node,
 		   nst->st_sc, nst->st_id, nst->st_msg_type,
 		   nst->st_msg_key,
 		   (long long)sock,
 		   (long long)send,
 		   (long long)status);

 out:
 	spin_unlock(&o2net_debug_lock);

 	return 0;
 }

 static void nst_seq_stop(struct seq_file *seq, void *v)
 {
 }

 static const struct seq_operations nst_seq_ops = {
 	.start = nst_seq_start,
 	.next = nst_seq_next,
 	.stop = nst_seq_stop,
 	.show = nst_seq_show,
 };

 static int nst_fop_open(struct inode *inode, struct file *file)
 {
 	struct o2net_send_tracking *dummy_nst;

 	dummy_nst = __seq_open_private(file, &nst_seq_ops, sizeof(*dummy_nst));
 	if (!dummy_nst)
 		return -ENOMEM;
 	o2net_debug_add_nst(dummy_nst);

 	return 0;
 }

 static int nst_fop_release(struct inode *inode, struct file *file)
 {
 	struct seq_file *seq = file->private_data;
 	struct o2net_send_tracking *dummy_nst = seq->private;

 	o2net_debug_del_nst(dummy_nst);
 	return seq_release_private(inode, file);
 }

 static const struct file_operations nst_seq_fops = {
 	.open = nst_fop_open,
 	.read = seq_read,
 	.llseek = seq_lseek,
 	.release = nst_fop_release,
 };

 void o2net_debug_add_sc(struct o2net_sock_container *sc)
 {
 	spin_lock(&o2net_debug_lock);
 	list_add(&sc->sc_net_debug_item, &sock_containers);
 	spin_unlock(&o2net_debug_lock);
 }

 void o2net_debug_del_sc(struct o2net_sock_container *sc)
 {
 	spin_lock(&o2net_debug_lock);
 	list_del_init(&sc->sc_net_debug_item);
 	spin_unlock(&o2net_debug_lock);
 }

 struct o2net_sock_debug {
 	int dbg_ctxt;
 	struct o2net_sock_container *dbg_sock;
 };

 static struct o2net_sock_container
 			*next_sc(struct o2net_sock_container *sc_start)
 {
 	struct o2net_sock_container *sc, *ret = NULL;

 	assert_spin_locked(&o2net_debug_lock);

 	list_for_each_entry(sc, &sc_start->sc_net_debug_item,
 			    sc_net_debug_item) {
 		/* discover the head of the list miscast as a sc */
 		if (&sc->sc_net_debug_item == &sock_containers)
 			break;

 		/* use sc_page to detect real scs in the list */
 		if (sc->sc_page != NULL) {
 			ret = sc;
 			break;
 		}
 	}

 	return ret;
 }

 static void *sc_seq_start(struct seq_file *seq, loff_t *pos)
 {
 	struct o2net_sock_debug *sd = seq->private;
 	struct o2net_sock_container *sc, *dummy_sc = sd->dbg_sock;

 	spin_lock(&o2net_debug_lock);
 	sc = next_sc(dummy_sc);
 	spin_unlock(&o2net_debug_lock);

 	return sc;
 }

 static void *sc_seq_next(struct seq_file *seq, void *v, loff_t *pos)
 {
 	struct o2net_sock_debug *sd = seq->private;
 	struct o2net_sock_container *sc, *dummy_sc = sd->dbg_sock;

 	spin_lock(&o2net_debug_lock);
 	sc = next_sc(dummy_sc);
 	list_del_init(&dummy_sc->sc_net_debug_item);
 	if (sc)
 		list_add(&dummy_sc->sc_net_debug_item, &sc->sc_net_debug_item);
 	spin_unlock(&o2net_debug_lock);

 	return sc; /* unused, just needs to be null when done */
 }

 #ifdef CONFIG_OCFS2_FS_STATS
 # define sc_send_count(_s)		((_s)->sc_send_count)
 # define sc_recv_count(_s)		((_s)->sc_recv_count)
 # define sc_tv_acquiry_total_ns(_s)	(ktime_to_ns((_s)->sc_tv_acquiry_total))
 # define sc_tv_send_total_ns(_s)	(ktime_to_ns((_s)->sc_tv_send_total))
 # define sc_tv_status_total_ns(_s)	(ktime_to_ns((_s)->sc_tv_status_total))
 # define sc_tv_process_total_ns(_s)	(ktime_to_ns((_s)->sc_tv_process_total))
 #else
 # define sc_send_count(_s)		(0U)
 # define sc_recv_count(_s)		(0U)
 # define sc_tv_acquiry_total_ns(_s)	(0LL)
 # define sc_tv_send_total_ns(_s)	(0LL)
 # define sc_tv_status_total_ns(_s)	(0LL)
 # define sc_tv_process_total_ns(_s)	(0LL)
 #endif

 /* So that debugfs.ocfs2 can determine which format is being used */
 #define O2NET_STATS_STR_VERSION		1
 static void sc_show_sock_stats(struct seq_file *seq,
 			       struct o2net_sock_container *sc)
 {
 	if (!sc)
 		return;

 	seq_printf(seq, "%d,%u,%lu,%lld,%lld,%lld,%lu,%lld\n", O2NET_STATS_STR_VERSION,
 		   sc->sc_node->nd_num, (unsigned long)sc_send_count(sc),
 		   (long long)sc_tv_acquiry_total_ns(sc),
 		   (long long)sc_tv_send_total_ns(sc),
 		   (long long)sc_tv_status_total_ns(sc),
 		   (unsigned long)sc_recv_count(sc),
 		   (long long)sc_tv_process_total_ns(sc));
 }

 static void sc_show_sock_container(struct seq_file *seq,
 				   struct o2net_sock_container *sc)
 {
 	struct inet_sock *inet = NULL;
 	__be32 saddr = 0, daddr = 0;
 	__be16 sport = 0, dport = 0;

 	if (!sc)
 		return;

 	if (sc->sc_sock) {
 		inet = inet_sk(sc->sc_sock->sk);
 		/* the stack's structs aren't sparse endian clean */
 		saddr = (__force __be32)inet->inet_saddr;
 		daddr = (__force __be32)inet->inet_daddr;
 		sport = (__force __be16)inet->inet_sport;
 		dport = (__force __be16)inet->inet_dport;
 	}

 	/* XXX sigh, inet-> doesn't have sparse annotation so any
 	 * use of it here generates a warning with -Wbitwise */
 	seq_printf(seq, "%p:\n"
 		   "  krefs:           %d\n"
 		   "  sock:            %pI4:%u -> "
 				      "%pI4:%u\n"
 		   "  remote node:     %s\n"
 		   "  page off:        %zu\n"
 		   "  handshake ok:    %u\n"
 		   "  timer:           %lld usecs\n"
 		   "  data ready:      %lld usecs\n"
 		   "  advance start:   %lld usecs\n"
 		   "  advance stop:    %lld usecs\n"
 		   "  func start:      %lld usecs\n"
 		   "  func stop:       %lld usecs\n"
 		   "  func key:        0x%08x\n"
 		   "  func type:       %u\n",
 		   sc,
 		   kref_read(&sc->sc_kref),
 		   &saddr, inet ? ntohs(sport) : 0,
 		   &daddr, inet ? ntohs(dport) : 0,
 		   sc->sc_node->nd_name,
 		   sc->sc_page_off,
 		   sc->sc_handshake_ok,
 		   (long long)ktime_to_us(sc->sc_tv_timer),
 		   (long long)ktime_to_us(sc->sc_tv_data_ready),
 		   (long long)ktime_to_us(sc->sc_tv_advance_start),
 		   (long long)ktime_to_us(sc->sc_tv_advance_stop),
 		   (long long)ktime_to_us(sc->sc_tv_func_start),
 		   (long long)ktime_to_us(sc->sc_tv_func_stop),
 		   sc->sc_msg_key,
 		   sc->sc_msg_type);
 }

 static int sc_seq_show(struct seq_file *seq, void *v)
 {
 	struct o2net_sock_debug *sd = seq->private;
 	struct o2net_sock_container *sc, *dummy_sc = sd->dbg_sock;

 	spin_lock(&o2net_debug_lock);
 	sc = next_sc(dummy_sc);

 	if (sc) {
 		if (sd->dbg_ctxt == SHOW_SOCK_CONTAINERS)
 			sc_show_sock_container(seq, sc);
 		else
 			sc_show_sock_stats(seq, sc);
 	}

 	spin_unlock(&o2net_debug_lock);

 	return 0;
 }

 static void sc_seq_stop(struct seq_file *seq, void *v)
 {
 }

 static const struct seq_operations sc_seq_ops = {
 	.start = sc_seq_start,
 	.next = sc_seq_next,
 	.stop = sc_seq_stop,
 	.show = sc_seq_show,
 };

 static int sc_common_open(struct file *file, int ctxt)
 {
 	struct o2net_sock_debug *sd;
 	struct o2net_sock_container *dummy_sc;

 	dummy_sc = kzalloc(sizeof(*dummy_sc), GFP_KERNEL);
 	if (!dummy_sc)
 		return -ENOMEM;

 	sd = __seq_open_private(file, &sc_seq_ops, sizeof(*sd));
 	if (!sd) {
 		kfree(dummy_sc);
 		return -ENOMEM;
 	}

 	sd->dbg_ctxt = ctxt;
 	sd->dbg_sock = dummy_sc;

 	o2net_debug_add_sc(dummy_sc);

 	return 0;
 }

 static int sc_fop_release(struct inode *inode, struct file *file)
 {
 	struct seq_file *seq = file->private_data;
 	struct o2net_sock_debug *sd = seq->private;
 	struct o2net_sock_container *dummy_sc = sd->dbg_sock;

 	o2net_debug_del_sc(dummy_sc);
 	kfree(dummy_sc);
 	return seq_release_private(inode, file);
 }

 static int stats_fop_open(struct inode *inode, struct file *file)
 {
 	return sc_common_open(file, SHOW_SOCK_STATS);
 }

 static const struct file_operations stats_seq_fops = {
 	.open = stats_fop_open,
 	.read = seq_read,
 	.llseek = seq_lseek,
 	.release = sc_fop_release,
 };

 static int sc_fop_open(struct inode *inode, struct file *file)
 {
 	return sc_common_open(file, SHOW_SOCK_CONTAINERS);
 }

 static const struct file_operations sc_seq_fops = {
 	.open = sc_fop_open,
 	.read = seq_read,
 	.llseek = seq_lseek,
 	.release = sc_fop_release,
 };

 static int o2net_fill_bitmap(char *buf, int len)
 {
 	unsigned long map[BITS_TO_LONGS(O2NM_MAX_NODES)];
 	int i = -1, out = 0;

 	o2net_fill_node_map(map, O2NM_MAX_NODES);

 	while ((i = find_next_bit(map, O2NM_MAX_NODES, i + 1)) < O2NM_MAX_NODES)
 		out += scnprintf(buf + out, PAGE_SIZE - out, "%d ", i);
 	out += scnprintf(buf + out, PAGE_SIZE - out, "\n");

 	return out;
 }

 static int nodes_fop_open(struct inode *inode, struct file *file)
 {
 	char *buf;

 	buf = kmalloc(PAGE_SIZE, GFP_KERNEL);
 	if (!buf)
 		return -ENOMEM;

 	i_size_write(inode, o2net_fill_bitmap(buf, PAGE_SIZE));

 	file->private_data = buf;

 	return 0;
 }

 static int o2net_debug_release(struct inode *inode, struct file *file)
 {
 	kfree(file->private_data);
 	return 0;
 }

 static ssize_t o2net_debug_read(struct file *file, char __user *buf,
 				size_t nbytes, loff_t *ppos)
 {
 	return simple_read_from_buffer(buf, nbytes, ppos, file->private_data,
 				       i_size_read(file->f_mapping->host));
 }

 static const struct file_operations nodes_fops = {
 	.open		= nodes_fop_open,
 	.release	= o2net_debug_release,
 	.read		= o2net_debug_read,
 	.llseek		= generic_file_llseek,
 };

 void o2net_debugfs_exit(void)
 {
 	debugfs_remove_recursive(o2net_dentry);
 }

 void o2net_debugfs_init(void)
 {
 	umode_t mode = S_IFREG|S_IRUSR;

 	o2net_dentry = debugfs_create_dir(O2NET_DEBUG_DIR, NULL);

 	debugfs_create_file(NST_DEBUG_NAME, mode, o2net_dentry, NULL,
 			    &nst_seq_fops);
 	debugfs_create_file(SC_DEBUG_NAME, mode, o2net_dentry, NULL,
 			    &sc_seq_fops);
 	debugfs_create_file(STATS_DEBUG_NAME, mode, o2net_dentry, NULL,
 			    &stats_seq_fops);
 	debugfs_create_file(NODES_DEBUG_NAME, mode, o2net_dentry, NULL,
 			    &nodes_fops);
 }

 #endif	/* CONFIG_DEBUG_FS */
	// SPDX-License-Identifier: GPL-2.0-or-later
	/*
	* netdebug.c
	*
	* debug functionality for o2net
	*
	* Copyright (C) 2005, 2008 Oracle. All rights reserved.
	*/

	#ifdef CONFIG_DEBUG_FS

	#include <linux/module.h>
	#include <linux/types.h>
	#include <linux/slab.h>
	#include <linux/idr.h>
	#include <linux/kref.h>
	#include <linux/seq_file.h>
	#include <linux/debugfs.h>

	#include <linux/uaccess.h>

	#include "tcp.h"
	#include "nodemanager.h"
	#define MLOG_MASK_PREFIX ML_TCP
	#include "masklog.h"

	#include "tcp_internal.h"

	#define O2NET_DEBUG_DIR "o2net"
	#define SC_DEBUG_NAME "sock_containers"
	#define NST_DEBUG_NAME "send_tracking"
	#define STATS_DEBUG_NAME "stats"
	#define NODES_DEBUG_NAME "connected_nodes"

	#define SHOW_SOCK_CONTAINERS 0
	#define SHOW_SOCK_STATS 1

	static struct dentry *o2net_dentry;

	static DEFINE_SPINLOCK(o2net_debug_lock);

	static LIST_HEAD(sock_containers);
	static LIST_HEAD(send_tracking);

	void o2net_debug_add_nst(struct o2net_send_tracking *nst)
	{
	spin_lock(&o2net_debug_lock);
	list_add(&nst->st_net_debug_item, &send_tracking);
	spin_unlock(&o2net_debug_lock);
	}

	void o2net_debug_del_nst(struct o2net_send_tracking *nst)
	{
	spin_lock(&o2net_debug_lock);
	if (!list_empty(&nst->st_net_debug_item))
	list_del_init(&nst->st_net_debug_item);
	spin_unlock(&o2net_debug_lock);
	}

	static struct o2net_send_tracking
	next_nst(struct o2net_send_tracking nst_start)
	{
	struct o2net_send_tracking nst, ret = NULL;

	assert_spin_locked(&o2net_debug_lock);

	list_for_each_entry(nst, &nst_start->st_net_debug_item,
	st_net_debug_item) {
	/* discover the head of the list */
	if (&nst->st_net_debug_item == &send_tracking)
	break;

	/* use st_task to detect real nsts in the list */
	if (nst->st_task != NULL) {
	ret = nst;
	break;
	}
	}

	return ret;
	}

	static void nst_seq_start(struct seq_file seq, loff_t *pos)
	{
	struct o2net_send_tracking nst, dummy_nst = seq->private;

	spin_lock(&o2net_debug_lock);
	nst = next_nst(dummy_nst);
	spin_unlock(&o2net_debug_lock);

	return nst;
	}

	static void nst_seq_next(struct seq_file seq, void v, loff_t pos)
	{
	struct o2net_send_tracking nst, dummy_nst = seq->private;

	spin_lock(&o2net_debug_lock);
	nst = next_nst(dummy_nst);
	list_del_init(&dummy_nst->st_net_debug_item);
	if (nst)
	list_add(&dummy_nst->st_net_debug_item,
	&nst->st_net_debug_item);
	spin_unlock(&o2net_debug_lock);

	return nst; /* unused, just needs to be null when done */
	}

	static int nst_seq_show(struct seq_file seq, void v)
	{
	struct o2net_send_tracking nst, dummy_nst = seq->private;
	ktime_t now;
	s64 sock, send, status;

	spin_lock(&o2net_debug_lock);
	nst = next_nst(dummy_nst);
	if (!nst)
	goto out;

	now = ktime_get();
	sock = ktime_to_us(ktime_sub(now, nst->st_sock_time));
	send = ktime_to_us(ktime_sub(now, nst->st_send_time));
	status = ktime_to_us(ktime_sub(now, nst->st_status_time));

	/* get_task_comm isn't exported. oh well. */
	seq_printf(seq, "%p:\n"
	" pid: %lu\n"
	" tgid: %lu\n"
	" process name: %s\n"
	" node: %u\n"
	" sc: %p\n"
	" message id: %d\n"
	" message type: %u\n"
	" message key: 0x%08x\n"
	" sock acquiry: %lld usecs ago\n"
	" send start: %lld usecs ago\n"
	" wait start: %lld usecs ago\n",
	nst, (unsigned long)task_pid_nr(nst->st_task),
	(unsigned long)nst->st_task->tgid,
	nst->st_task->comm, nst->st_node,
	nst->st_sc, nst->st_id, nst->st_msg_type,
	nst->st_msg_key,
	(long long)sock,
	(long long)send,
	(long long)status);

	out:
	spin_unlock(&o2net_debug_lock);

	return 0;
	}

	static void nst_seq_stop(struct seq_file seq, void v)
	{
	}

	static const struct seq_operations nst_seq_ops = {
	.start = nst_seq_start,
	.next = nst_seq_next,
	.stop = nst_seq_stop,
	.show = nst_seq_show,
	};

	static int nst_fop_open(struct inode inode, struct file file)
	{
	struct o2net_send_tracking *dummy_nst;

	dummy_nst = __seq_open_private(file, &nst_seq_ops, sizeof(*dummy_nst));
	if (!dummy_nst)
	return -ENOMEM;
	o2net_debug_add_nst(dummy_nst);

	return 0;
	}

	static int nst_fop_release(struct inode inode, struct file file)
	{
	struct seq_file *seq = file->private_data;
	struct o2net_send_tracking *dummy_nst = seq->private;

	o2net_debug_del_nst(dummy_nst);
	return seq_release_private(inode, file);
	}

	static const struct file_operations nst_seq_fops = {
	.open = nst_fop_open,
	.read = seq_read,
	.llseek = seq_lseek,
	.release = nst_fop_release,
	};

	void o2net_debug_add_sc(struct o2net_sock_container *sc)
	{
	spin_lock(&o2net_debug_lock);
	list_add(&sc->sc_net_debug_item, &sock_containers);
	spin_unlock(&o2net_debug_lock);
	}

	void o2net_debug_del_sc(struct o2net_sock_container *sc)
	{
	spin_lock(&o2net_debug_lock);
	list_del_init(&sc->sc_net_debug_item);
	spin_unlock(&o2net_debug_lock);
	}

	struct o2net_sock_debug {
	int dbg_ctxt;
	struct o2net_sock_container *dbg_sock;
	};

	static struct o2net_sock_container
	next_sc(struct o2net_sock_container sc_start)
	{
	struct o2net_sock_container sc, ret = NULL;

	assert_spin_locked(&o2net_debug_lock);

	list_for_each_entry(sc, &sc_start->sc_net_debug_item,
	sc_net_debug_item) {
	/* discover the head of the list miscast as a sc */
	if (&sc->sc_net_debug_item == &sock_containers)
	break;

	/* use sc_page to detect real scs in the list */
	if (sc->sc_page != NULL) {
	ret = sc;
	break;
	}
	}

	return ret;
	}

	static void sc_seq_start(struct seq_file seq, loff_t *pos)
	{
	struct o2net_sock_debug *sd = seq->private;
	struct o2net_sock_container sc, dummy_sc = sd->dbg_sock;

	spin_lock(&o2net_debug_lock);
	sc = next_sc(dummy_sc);
	spin_unlock(&o2net_debug_lock);

	return sc;
	}

	static void sc_seq_next(struct seq_file seq, void v, loff_t pos)
	{
	struct o2net_sock_debug *sd = seq->private;
	struct o2net_sock_container sc, dummy_sc = sd->dbg_sock;

	spin_lock(&o2net_debug_lock);
	sc = next_sc(dummy_sc);
	list_del_init(&dummy_sc->sc_net_debug_item);
	if (sc)
	list_add(&dummy_sc->sc_net_debug_item, &sc->sc_net_debug_item);
	spin_unlock(&o2net_debug_lock);

	return sc; /* unused, just needs to be null when done */
	}

	#ifdef CONFIG_OCFS2_FS_STATS
	# define sc_send_count(_s) ((_s)->sc_send_count)
	# define sc_recv_count(_s) ((_s)->sc_recv_count)
	# define sc_tv_acquiry_total_ns(_s) (ktime_to_ns((_s)->sc_tv_acquiry_total))
	# define sc_tv_send_total_ns(_s) (ktime_to_ns((_s)->sc_tv_send_total))
	# define sc_tv_status_total_ns(_s) (ktime_to_ns((_s)->sc_tv_status_total))
	# define sc_tv_process_total_ns(_s) (ktime_to_ns((_s)->sc_tv_process_total))
	#else
	# define sc_send_count(_s) (0U)
	# define sc_recv_count(_s) (0U)
	# define sc_tv_acquiry_total_ns(_s) (0LL)
	# define sc_tv_send_total_ns(_s) (0LL)
	# define sc_tv_status_total_ns(_s) (0LL)
	# define sc_tv_process_total_ns(_s) (0LL)
	#endif

	/* So that debugfs.ocfs2 can determine which format is being used */
	#define O2NET_STATS_STR_VERSION 1
	static void sc_show_sock_stats(struct seq_file *seq,
	struct o2net_sock_container *sc)
	{
	if (!sc)
	return;

	seq_printf(seq, "%d,%u,%lu,%lld,%lld,%lld,%lu,%lld\n", O2NET_STATS_STR_VERSION,
	sc->sc_node->nd_num, (unsigned long)sc_send_count(sc),
	(long long)sc_tv_acquiry_total_ns(sc),
	(long long)sc_tv_send_total_ns(sc),
	(long long)sc_tv_status_total_ns(sc),
	(unsigned long)sc_recv_count(sc),
	(long long)sc_tv_process_total_ns(sc));
	}

	static void sc_show_sock_container(struct seq_file *seq,
	struct o2net_sock_container *sc)
	{
	struct inet_sock *inet = NULL;
	__be32 saddr = 0, daddr = 0;
	__be16 sport = 0, dport = 0;

	if (!sc)
	return;

	if (sc->sc_sock) {
	inet = inet_sk(sc->sc_sock->sk);
	/* the stack's structs aren't sparse endian clean */
	saddr = (__force __be32)inet->inet_saddr;
	daddr = (__force __be32)inet->inet_daddr;
	sport = (__force __be16)inet->inet_sport;
	dport = (__force __be16)inet->inet_dport;
	}

	/* XXX sigh, inet-> doesn't have sparse annotation so any
	* use of it here generates a warning with -Wbitwise */
	seq_printf(seq, "%p:\n"
	" krefs: %d\n"
	" sock: %pI4:%u -> "
	"%pI4:%u\n"
	" remote node: %s\n"
	" page off: %zu\n"
	" handshake ok: %u\n"
	" timer: %lld usecs\n"
	" data ready: %lld usecs\n"
	" advance start: %lld usecs\n"
	" advance stop: %lld usecs\n"
	" func start: %lld usecs\n"
	" func stop: %lld usecs\n"
	" func key: 0x%08x\n"
	" func type: %u\n",
	sc,
	kref_read(&sc->sc_kref),
	&saddr, inet ? ntohs(sport) : 0,
	&daddr, inet ? ntohs(dport) : 0,
	sc->sc_node->nd_name,
	sc->sc_page_off,
	sc->sc_handshake_ok,
	(long long)ktime_to_us(sc->sc_tv_timer),
	(long long)ktime_to_us(sc->sc_tv_data_ready),
	(long long)ktime_to_us(sc->sc_tv_advance_start),
	(long long)ktime_to_us(sc->sc_tv_advance_stop),
	(long long)ktime_to_us(sc->sc_tv_func_start),
	(long long)ktime_to_us(sc->sc_tv_func_stop),
	sc->sc_msg_key,
	sc->sc_msg_type);
	}

	static int sc_seq_show(struct seq_file seq, void v)
	{
	struct o2net_sock_debug *sd = seq->private;
	struct o2net_sock_container sc, dummy_sc = sd->dbg_sock;

	spin_lock(&o2net_debug_lock);
	sc = next_sc(dummy_sc);

	if (sc) {
	if (sd->dbg_ctxt == SHOW_SOCK_CONTAINERS)
	sc_show_sock_container(seq, sc);
	else
	sc_show_sock_stats(seq, sc);
	}

	spin_unlock(&o2net_debug_lock);

	return 0;
	}

	static void sc_seq_stop(struct seq_file seq, void v)
	{
	}

	static const struct seq_operations sc_seq_ops = {
	.start = sc_seq_start,
	.next = sc_seq_next,
	.stop = sc_seq_stop,
	.show = sc_seq_show,
	};

	static int sc_common_open(struct file *file, int ctxt)
	{
	struct o2net_sock_debug *sd;
	struct o2net_sock_container *dummy_sc;

	dummy_sc = kzalloc(sizeof(*dummy_sc), GFP_KERNEL);
	if (!dummy_sc)
	return -ENOMEM;

	sd = __seq_open_private(file, &sc_seq_ops, sizeof(*sd));
	if (!sd) {
	kfree(dummy_sc);
	return -ENOMEM;
	}

	sd->dbg_ctxt = ctxt;
	sd->dbg_sock = dummy_sc;

	o2net_debug_add_sc(dummy_sc);

	return 0;
	}

	static int sc_fop_release(struct inode inode, struct file file)
	{
	struct seq_file *seq = file->private_data;
	struct o2net_sock_debug *sd = seq->private;
	struct o2net_sock_container *dummy_sc = sd->dbg_sock;

	o2net_debug_del_sc(dummy_sc);
	kfree(dummy_sc);
	return seq_release_private(inode, file);
	}

	static int stats_fop_open(struct inode inode, struct file file)
	{
	return sc_common_open(file, SHOW_SOCK_STATS);
	}

	static const struct file_operations stats_seq_fops = {
	.open = stats_fop_open,
	.read = seq_read,
	.llseek = seq_lseek,
	.release = sc_fop_release,
	};

	static int sc_fop_open(struct inode inode, struct file file)
	{
	return sc_common_open(file, SHOW_SOCK_CONTAINERS);
	}

	static const struct file_operations sc_seq_fops = {
	.open = sc_fop_open,
	.read = seq_read,
	.llseek = seq_lseek,
	.release = sc_fop_release,
	};

	static int o2net_fill_bitmap(char *buf, int len)
	{
	unsigned long map[BITS_TO_LONGS(O2NM_MAX_NODES)];
	int i = -1, out = 0;

	o2net_fill_node_map(map, O2NM_MAX_NODES);

	while ((i = find_next_bit(map, O2NM_MAX_NODES, i + 1)) < O2NM_MAX_NODES)
	out += scnprintf(buf + out, PAGE_SIZE - out, "%d ", i);
	out += scnprintf(buf + out, PAGE_SIZE - out, "\n");

	return out;
	}

	static int nodes_fop_open(struct inode inode, struct file file)
	{
	char *buf;

	buf = kmalloc(PAGE_SIZE, GFP_KERNEL);
	if (!buf)
	return -ENOMEM;

	i_size_write(inode, o2net_fill_bitmap(buf, PAGE_SIZE));

	file->private_data = buf;

	return 0;
	}

	static int o2net_debug_release(struct inode inode, struct file file)
	{
	kfree(file->private_data);
	return 0;
	}

	static ssize_t o2net_debug_read(struct file file, char __user buf,
	size_t nbytes, loff_t *ppos)
	{
	return simple_read_from_buffer(buf, nbytes, ppos, file->private_data,
	i_size_read(file->f_mapping->host));
	}

	static const struct file_operations nodes_fops = {
	.open = nodes_fop_open,
	.release = o2net_debug_release,
	.read = o2net_debug_read,
	.llseek = generic_file_llseek,
	};

	void o2net_debugfs_exit(void)
	{
	debugfs_remove_recursive(o2net_dentry);
	}

	void o2net_debugfs_init(void)
	{
	umode_t mode = S_IFREG\|S_IRUSR;

	o2net_dentry = debugfs_create_dir(O2NET_DEBUG_DIR, NULL);

	debugfs_create_file(NST_DEBUG_NAME, mode, o2net_dentry, NULL,
	&nst_seq_fops);
	debugfs_create_file(SC_DEBUG_NAME, mode, o2net_dentry, NULL,
	&sc_seq_fops);
	debugfs_create_file(STATS_DEBUG_NAME, mode, o2net_dentry, NULL,
	&stats_seq_fops);
	debugfs_create_file(NODES_DEBUG_NAME, mode, o2net_dentry, NULL,
	&nodes_fops);
	}

	#endif /* CONFIG_DEBUG_FS */