[mirror_ubuntu-bionic-kernel.git] / fs / ocfs2 / heartbeat.c

/* -*- mode: c; c-basic-offset: 8; -*-
 * vim: noexpandtab sw=8 ts=8 sts=0:
 *
 * heartbeat.c
 *
 * Register ourselves with the heartbaet service, keep our node maps
 * up to date, and fire off recovery when needed.
 *
 * Copyright (C) 2002, 2004 Oracle.  All rights reserved.
 *
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of the GNU General Public
 * License as published by the Free Software Foundation; either
 * version 2 of the License, or (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 * General Public License for more details.
 *
 * You should have received a copy of the GNU General Public
 * License along with this program; if not, write to the
 * Free Software Foundation, Inc., 59 Temple Place - Suite 330,
 * Boston, MA 021110-1307, USA.
 */

#include <linux/fs.h>
#include <linux/types.h>
#include <linux/slab.h>
#include <linux/highmem.h>
#include <linux/kmod.h>

#include <cluster/heartbeat.h>
#include <cluster/nodemanager.h>

#include <dlm/dlmapi.h>

#define MLOG_MASK_PREFIX ML_SUPER
#include <cluster/masklog.h>

#include "ocfs2.h"

#include "alloc.h"
#include "heartbeat.h"
#include "inode.h"
#include "journal.h"
#include "vote.h"

#include "buffer_head_io.h"

#define OCFS2_HB_NODE_DOWN_PRI     (0x0000002)
#define OCFS2_HB_NODE_UP_PRI	   OCFS2_HB_NODE_DOWN_PRI

static inline void __ocfs2_node_map_set_bit(struct ocfs2_node_map *map,
					    int bit);
static inline void __ocfs2_node_map_clear_bit(struct ocfs2_node_map *map,
					      int bit);
static inline int __ocfs2_node_map_is_empty(struct ocfs2_node_map *map);
static void __ocfs2_node_map_dup(struct ocfs2_node_map *target,
				 struct ocfs2_node_map *from);
static void __ocfs2_node_map_set(struct ocfs2_node_map *target,
				 struct ocfs2_node_map *from);

void ocfs2_init_node_maps(struct ocfs2_super *osb)
{
	spin_lock_init(&osb->node_map_lock);
	ocfs2_node_map_init(&osb->mounted_map);
	ocfs2_node_map_init(&osb->recovery_map);
	ocfs2_node_map_init(&osb->umount_map);
}

static void ocfs2_do_node_down(int node_num,
			       struct ocfs2_super *osb)
{
	BUG_ON(osb->node_num == node_num);

	mlog(0, "ocfs2: node down event for %d\n", node_num);

	if (!osb->dlm) {
		/*
		 * No DLM means we're not even ready to participate yet.
		 * We check the slots after the DLM comes up, so we will
		 * notice the node death then.  We can safely ignore it
		 * here.
		 */
		return;
	}

	if (ocfs2_node_map_test_bit(osb, &osb->umount_map, node_num)) {
		/* If a node is in the umount map, then we've been
		 * expecting him to go down and we know ahead of time
		 * that recovery is not necessary. */
		ocfs2_node_map_clear_bit(osb, &osb->umount_map, node_num);
		return;
	}

	ocfs2_recovery_thread(osb, node_num);

	ocfs2_remove_node_from_vote_queues(osb, node_num);
}

static void ocfs2_hb_node_down_cb(struct o2nm_node *node,
				  int node_num,
				  void *data)
{
	ocfs2_do_node_down(node_num, (struct ocfs2_super *) data);
}

/* Called from the dlm when it's about to evict a node. We may also
 * get a heartbeat callback later. */
static void ocfs2_dlm_eviction_cb(int node_num,
				  void *data)
{
	struct ocfs2_super *osb = (struct ocfs2_super *) data;
	struct super_block *sb = osb->sb;

	mlog(ML_NOTICE, "device (%u,%u): dlm has evicted node %d\n",
	     MAJOR(sb->s_dev), MINOR(sb->s_dev), node_num);

	ocfs2_do_node_down(node_num, osb);
}

static void ocfs2_hb_node_up_cb(struct o2nm_node *node,
				int node_num,
				void *data)
{
	struct ocfs2_super *osb = data;

	BUG_ON(osb->node_num == node_num);

	mlog(0, "node up event for %d\n", node_num);
	ocfs2_node_map_clear_bit(osb, &osb->umount_map, node_num);
}

void ocfs2_setup_hb_callbacks(struct ocfs2_super *osb)
{
	o2hb_setup_callback(&osb->osb_hb_down, O2HB_NODE_DOWN_CB,
			    ocfs2_hb_node_down_cb, osb,
			    OCFS2_HB_NODE_DOWN_PRI);

	o2hb_setup_callback(&osb->osb_hb_up, O2HB_NODE_UP_CB,
			    ocfs2_hb_node_up_cb, osb, OCFS2_HB_NODE_UP_PRI);

	/* Not exactly a heartbeat callback, but leads to essentially
	 * the same path so we set it up here. */
	dlm_setup_eviction_cb(&osb->osb_eviction_cb,
			      ocfs2_dlm_eviction_cb,
			      osb);
}

/* Most functions here are just stubs for now... */
int ocfs2_register_hb_callbacks(struct ocfs2_super *osb)
{
	int status;

	status = o2hb_register_callback(&osb->osb_hb_down);
	if (status < 0) {
		mlog_errno(status);
		goto bail;
	}

	status = o2hb_register_callback(&osb->osb_hb_up);
	if (status < 0)
		mlog_errno(status);

bail:
	return status;
}

void ocfs2_clear_hb_callbacks(struct ocfs2_super *osb)
{
	int status;

	status = o2hb_unregister_callback(&osb->osb_hb_down);
	if (status < 0)
		mlog_errno(status);

	status = o2hb_unregister_callback(&osb->osb_hb_up);
	if (status < 0)
		mlog_errno(status);
}

void ocfs2_stop_heartbeat(struct ocfs2_super *osb)
{
	int ret;
	char *argv[5], *envp[3];

	if (!osb->uuid_str) {
		/* This can happen if we don't get far enough in mount... */
		mlog(0, "No UUID with which to stop heartbeat!\n\n");
		return;
	}

	argv[0] = (char *)o2nm_get_hb_ctl_path();
	argv[1] = "-K";
	argv[2] = "-u";
	argv[3] = osb->uuid_str;
	argv[4] = NULL;

	mlog(0, "Run: %s %s %s %s\n", argv[0], argv[1], argv[2], argv[3]);

	/* minimal command environment taken from cpu_run_sbin_hotplug */
	envp[0] = "HOME=/";
	envp[1] = "PATH=/sbin:/bin:/usr/sbin:/usr/bin";
	envp[2] = NULL;

	ret = call_usermodehelper(argv[0], argv, envp, 1);
	if (ret < 0)
		mlog_errno(ret);
}

/* special case -1 for now
 * TODO: should *really* make sure the calling func never passes -1!!  */
void ocfs2_node_map_init(struct ocfs2_node_map *map)
{
	map->num_nodes = OCFS2_NODE_MAP_MAX_NODES;
	memset(map->map, 0, BITS_TO_LONGS(OCFS2_NODE_MAP_MAX_NODES) *
	       sizeof(unsigned long));
}

static inline void __ocfs2_node_map_set_bit(struct ocfs2_node_map *map,
					    int bit)
{
	set_bit(bit, map->map);
}

void ocfs2_node_map_set_bit(struct ocfs2_super *osb,
			    struct ocfs2_node_map *map,
			    int bit)
{
	if (bit==-1)
		return;
	BUG_ON(bit >= map->num_nodes);
	spin_lock(&osb->node_map_lock);
	__ocfs2_node_map_set_bit(map, bit);
	spin_unlock(&osb->node_map_lock);
}

static inline void __ocfs2_node_map_clear_bit(struct ocfs2_node_map *map,
					      int bit)
{
	clear_bit(bit, map->map);
}

void ocfs2_node_map_clear_bit(struct ocfs2_super *osb,
			      struct ocfs2_node_map *map,
			      int bit)
{
	if (bit==-1)
		return;
	BUG_ON(bit >= map->num_nodes);
	spin_lock(&osb->node_map_lock);
	__ocfs2_node_map_clear_bit(map, bit);
	spin_unlock(&osb->node_map_lock);
}

int ocfs2_node_map_test_bit(struct ocfs2_super *osb,
			    struct ocfs2_node_map *map,
			    int bit)
{
	int ret;
	if (bit >= map->num_nodes) {
		mlog(ML_ERROR, "bit=%d map->num_nodes=%d\n", bit, map->num_nodes);
		BUG();
	}
	spin_lock(&osb->node_map_lock);
	ret = test_bit(bit, map->map);
	spin_unlock(&osb->node_map_lock);
	return ret;
}

static inline int __ocfs2_node_map_is_empty(struct ocfs2_node_map *map)
{
	int bit;
	bit = find_next_bit(map->map, map->num_nodes, 0);
	if (bit < map->num_nodes)
		return 0;
	return 1;
}

int ocfs2_node_map_is_empty(struct ocfs2_super *osb,
			    struct ocfs2_node_map *map)
{
	int ret;
	BUG_ON(map->num_nodes == 0);
	spin_lock(&osb->node_map_lock);
	ret = __ocfs2_node_map_is_empty(map);
	spin_unlock(&osb->node_map_lock);
	return ret;
}

static void __ocfs2_node_map_dup(struct ocfs2_node_map *target,
				 struct ocfs2_node_map *from)
{
	BUG_ON(from->num_nodes == 0);
	ocfs2_node_map_init(target);
	__ocfs2_node_map_set(target, from);
}

/* returns 1 if bit is the only bit set in target, 0 otherwise */
int ocfs2_node_map_is_only(struct ocfs2_super *osb,
			   struct ocfs2_node_map *target,
			   int bit)
{
	struct ocfs2_node_map temp;
	int ret;

	spin_lock(&osb->node_map_lock);
	__ocfs2_node_map_dup(&temp, target);
	__ocfs2_node_map_clear_bit(&temp, bit);
	ret = __ocfs2_node_map_is_empty(&temp);
	spin_unlock(&osb->node_map_lock);

	return ret;
}

static void __ocfs2_node_map_set(struct ocfs2_node_map *target,
				 struct ocfs2_node_map *from)
{
	int num_longs, i;

	BUG_ON(target->num_nodes != from->num_nodes);
	BUG_ON(target->num_nodes == 0);

	num_longs = BITS_TO_LONGS(target->num_nodes);
	for (i = 0; i < num_longs; i++)
		target->map[i] = from->map[i];
}

/* Returns whether the recovery bit was actually set - it may not be
 * if a node is still marked as needing recovery */
int ocfs2_recovery_map_set(struct ocfs2_super *osb,
			   int num)
{
	int set = 0;

	spin_lock(&osb->node_map_lock);

	__ocfs2_node_map_clear_bit(&osb->mounted_map, num);

	if (!test_bit(num, osb->recovery_map.map)) {
	    __ocfs2_node_map_set_bit(&osb->recovery_map, num);
	    set = 1;
	}

	spin_unlock(&osb->node_map_lock);

	return set;
}

void ocfs2_recovery_map_clear(struct ocfs2_super *osb,
			      int num)
{
	ocfs2_node_map_clear_bit(osb, &osb->recovery_map, num);
}

int ocfs2_node_map_iterate(struct ocfs2_super *osb,
			   struct ocfs2_node_map *map,
			   int idx)
{
	int i = idx;

	idx = O2NM_INVALID_NODE_NUM;
	spin_lock(&osb->node_map_lock);
	if ((i != O2NM_INVALID_NODE_NUM) &&
	    (i >= 0) &&
	    (i < map->num_nodes)) {
		while(i < map->num_nodes) {
			if (test_bit(i, map->map)) {
				idx = i;
				break;
			}
			i++;
		}
	}
	spin_unlock(&osb->node_map_lock);
	return idx;
}
Commit	Line	Data
ccd979bd MF	1	/* -- mode: c; c-basic-offset: 8; --
	2	* vim: noexpandtab sw=8 ts=8 sts=0:
	3	*
	4	* heartbeat.c
	5	*
	6	* Register ourselves with the heartbaet service, keep our node maps
	7	* up to date, and fire off recovery when needed.
	8	*
	9	* Copyright (C) 2002, 2004 Oracle. All rights reserved.
	10	*
	11	* This program is free software; you can redistribute it and/or
	12	* modify it under the terms of the GNU General Public
	13	* License as published by the Free Software Foundation; either
	14	* version 2 of the License, or (at your option) any later version.
	15	*
	16	* This program is distributed in the hope that it will be useful,
	17	* but WITHOUT ANY WARRANTY; without even the implied warranty of
	18	* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
	19	* General Public License for more details.
	20	*
	21	* You should have received a copy of the GNU General Public
	22	* License along with this program; if not, write to the
	23	* Free Software Foundation, Inc., 59 Temple Place - Suite 330,
	24	* Boston, MA 021110-1307, USA.
	25	*/
	26
	27	#include <linux/fs.h>
	28	#include <linux/types.h>
	29	#include <linux/slab.h>
	30	#include <linux/highmem.h>
	31	#include <linux/kmod.h>
	32
	33	#include <cluster/heartbeat.h>
	34	#include <cluster/nodemanager.h>
	35
	36	#include <dlm/dlmapi.h>
	37
	38	#define MLOG_MASK_PREFIX ML_SUPER
	39	#include <cluster/masklog.h>
	40
	41	#include "ocfs2.h"
	42
	43	#include "alloc.h"
	44	#include "heartbeat.h"
	45	#include "inode.h"
	46	#include "journal.h"
	47	#include "vote.h"
	48
	49	#include "buffer_head_io.h"
	50
	51	#define OCFS2_HB_NODE_DOWN_PRI (0x0000002)
	52	#define OCFS2_HB_NODE_UP_PRI OCFS2_HB_NODE_DOWN_PRI
	53
	54	static inline void __ocfs2_node_map_set_bit(struct ocfs2_node_map *map,
	55	int bit);
	56	static inline void __ocfs2_node_map_clear_bit(struct ocfs2_node_map *map,
	57	int bit);
	58	static inline int __ocfs2_node_map_is_empty(struct ocfs2_node_map *map);
	59	static void __ocfs2_node_map_dup(struct ocfs2_node_map *target,
	60	struct ocfs2_node_map *from);
	61	static void __ocfs2_node_map_set(struct ocfs2_node_map *target,
	62	struct ocfs2_node_map *from);
	63
	64	void ocfs2_init_node_maps(struct ocfs2_super *osb)
65	{
66	spin_lock_init(&osb->node_map_lock);
67	ocfs2_node_map_init(&osb->mounted_map);
68	ocfs2_node_map_init(&osb->recovery_map);
69	ocfs2_node_map_init(&osb->umount_map);
70	}
71
72	static void ocfs2_do_node_down(int node_num,
73	struct ocfs2_super *osb)
74	{
75	BUG_ON(osb->node_num == node_num);
76
77	mlog(0, "ocfs2: node down event for %d\n", node_num);
78
79	if (!osb->dlm) {
80	/*
81	* No DLM means we're not even ready to participate yet.
82	* We check the slots after the DLM comes up, so we will
83	* notice the node death then. We can safely ignore it
84	* here.
85	*/
86	return;
87	}
88
89	if (ocfs2_node_map_test_bit(osb, &osb->umount_map, node_num)) {
90	/* If a node is in the umount map, then we've been
91	* expecting him to go down and we know ahead of time
92	* that recovery is not necessary. */
93	ocfs2_node_map_clear_bit(osb, &osb->umount_map, node_num);
94	return;
95	}
96
97	ocfs2_recovery_thread(osb, node_num);
98
99	ocfs2_remove_node_from_vote_queues(osb, node_num);
100	}
101
102	static void ocfs2_hb_node_down_cb(struct o2nm_node *node,
103	int node_num,
104	void *data)
105	{
106	ocfs2_do_node_down(node_num, (struct ocfs2_super *) data);
107	}
108
109	/* Called from the dlm when it's about to evict a node. We may also
110	* get a heartbeat callback later. */
111	static void ocfs2_dlm_eviction_cb(int node_num,
112	void *data)
113	{
114	struct ocfs2_super osb = (struct ocfs2_super ) data;
115	struct super_block *sb = osb->sb;
116
117	mlog(ML_NOTICE, "device (%u,%u): dlm has evicted node %d\n",
118	MAJOR(sb->s_dev), MINOR(sb->s_dev), node_num);
119
120	ocfs2_do_node_down(node_num, osb);
121	}
122
123	static void ocfs2_hb_node_up_cb(struct o2nm_node *node,
124	int node_num,
125	void *data)
126	{
127	struct ocfs2_super *osb = data;
128
129	BUG_ON(osb->node_num == node_num);
130
131	mlog(0, "node up event for %d\n", node_num);
132	ocfs2_node_map_clear_bit(osb, &osb->umount_map, node_num);
133	}
134
135	void ocfs2_setup_hb_callbacks(struct ocfs2_super *osb)
136	{
137	o2hb_setup_callback(&osb->osb_hb_down, O2HB_NODE_DOWN_CB,
138	ocfs2_hb_node_down_cb, osb,
139	OCFS2_HB_NODE_DOWN_PRI);
140
141	o2hb_setup_callback(&osb->osb_hb_up, O2HB_NODE_UP_CB,
142	ocfs2_hb_node_up_cb, osb, OCFS2_HB_NODE_UP_PRI);
143
144	/* Not exactly a heartbeat callback, but leads to essentially
145	* the same path so we set it up here. */
146	dlm_setup_eviction_cb(&osb->osb_eviction_cb,
147	ocfs2_dlm_eviction_cb,
148	osb);
149	}
150
151	/* Most functions here are just stubs for now... */
152	int ocfs2_register_hb_callbacks(struct ocfs2_super *osb)
153	{
154	int status;
155
156	status = o2hb_register_callback(&osb->osb_hb_down);
157	if (status < 0) {
158	mlog_errno(status);
159	goto bail;
160	}
161
162	status = o2hb_register_callback(&osb->osb_hb_up);
163	if (status < 0)
164	mlog_errno(status);
165
166	bail:
167	return status;
168	}
169
170	void ocfs2_clear_hb_callbacks(struct ocfs2_super *osb)
171	{
172	int status;
173
174	status = o2hb_unregister_callback(&osb->osb_hb_down);
175	if (status < 0)
176	mlog_errno(status);
177
178	status = o2hb_unregister_callback(&osb->osb_hb_up);
179	if (status < 0)
180	mlog_errno(status);
181	}
182
183	void ocfs2_stop_heartbeat(struct ocfs2_super *osb)
184	{
185	int ret;
186	char argv[5], envp[3];
187
188	if (!osb->uuid_str) {
189	/* This can happen if we don't get far enough in mount... */
190	mlog(0, "No UUID with which to stop heartbeat!\n\n");
191	return;
192	}
193
194	argv[0] = (char *)o2nm_get_hb_ctl_path();
195	argv[1] = "-K";
196	argv[2] = "-u";
197	argv[3] = osb->uuid_str;
198	argv[4] = NULL;
199
200	mlog(0, "Run: %s %s %s %s\n", argv[0], argv[1], argv[2], argv[3]);
201
202	/* minimal command environment taken from cpu_run_sbin_hotplug */
203	envp[0] = "HOME=/";
204	envp[1] = "PATH=/sbin:/bin:/usr/sbin:/usr/bin";
205	envp[2] = NULL;
206
207	ret = call_usermodehelper(argv[0], argv, envp, 1);
208	if (ret < 0)
209	mlog_errno(ret);
210	}
211
212	/* special case -1 for now
213	* TODO: should really make sure the calling func never passes -1!! */
214	void ocfs2_node_map_init(struct ocfs2_node_map *map)
215	{
216	map->num_nodes = OCFS2_NODE_MAP_MAX_NODES;
217	memset(map->map, 0, BITS_TO_LONGS(OCFS2_NODE_MAP_MAX_NODES) *
218	sizeof(unsigned long));
219	}
220
221	static inline void __ocfs2_node_map_set_bit(struct ocfs2_node_map *map,
222	int bit)
223	{
224	set_bit(bit, map->map);
225	}
226
227	void ocfs2_node_map_set_bit(struct ocfs2_super *osb,
228	struct ocfs2_node_map *map,
229	int bit)
230	{
231	if (bit==-1)
232	return;
233	BUG_ON(bit >= map->num_nodes);
234	spin_lock(&osb->node_map_lock);
235	__ocfs2_node_map_set_bit(map, bit);
236	spin_unlock(&osb->node_map_lock);
237	}
238
239	static inline void __ocfs2_node_map_clear_bit(struct ocfs2_node_map *map,
240	int bit)
241	{
242	clear_bit(bit, map->map);
243	}
244
245	void ocfs2_node_map_clear_bit(struct ocfs2_super *osb,
246	struct ocfs2_node_map *map,
247	int bit)
248	{
249	if (bit==-1)
250	return;
251	BUG_ON(bit >= map->num_nodes);
252	spin_lock(&osb->node_map_lock);
253	__ocfs2_node_map_clear_bit(map, bit);
254	spin_unlock(&osb->node_map_lock);
255	}
256
257	int ocfs2_node_map_test_bit(struct ocfs2_super *osb,
258	struct ocfs2_node_map *map,
259	int bit)
260	{
261	int ret;
262	if (bit >= map->num_nodes) {
263	mlog(ML_ERROR, "bit=%d map->num_nodes=%d\n", bit, map->num_nodes);
264	BUG();
265	}
266	spin_lock(&osb->node_map_lock);
267	ret = test_bit(bit, map->map);
268	spin_unlock(&osb->node_map_lock);
269	return ret;
270	}
271
272	static inline int __ocfs2_node_map_is_empty(struct ocfs2_node_map *map)
273	{
274	int bit;
275	bit = find_next_bit(map->map, map->num_nodes, 0);
276	if (bit < map->num_nodes)
277	return 0;
278	return 1;
279	}
280
281	int ocfs2_node_map_is_empty(struct ocfs2_super *osb,
282	struct ocfs2_node_map *map)
283	{
284	int ret;
285	BUG_ON(map->num_nodes == 0);
286	spin_lock(&osb->node_map_lock);
287	ret = __ocfs2_node_map_is_empty(map);
288	spin_unlock(&osb->node_map_lock);
289	return ret;
290	}
291
292	static void __ocfs2_node_map_dup(struct ocfs2_node_map *target,
293	struct ocfs2_node_map *from)
294	{
295	BUG_ON(from->num_nodes == 0);
296	ocfs2_node_map_init(target);
297	__ocfs2_node_map_set(target, from);
298	}
299
300	/* returns 1 if bit is the only bit set in target, 0 otherwise */
301	int ocfs2_node_map_is_only(struct ocfs2_super *osb,
302	struct ocfs2_node_map *target,
303	int bit)
304	{
305	struct ocfs2_node_map temp;
306	int ret;
307
308	spin_lock(&osb->node_map_lock);
309	__ocfs2_node_map_dup(&temp, target);
310	__ocfs2_node_map_clear_bit(&temp, bit);
311	ret = __ocfs2_node_map_is_empty(&temp);
312	spin_unlock(&osb->node_map_lock);
313
314	return ret;
315	}
316
317	static void __ocfs2_node_map_set(struct ocfs2_node_map *target,
318	struct ocfs2_node_map *from)
319	{
320	int num_longs, i;
321
322	BUG_ON(target->num_nodes != from->num_nodes);
323	BUG_ON(target->num_nodes == 0);
324
325	num_longs = BITS_TO_LONGS(target->num_nodes);
326	for (i = 0; i < num_longs; i++)
327	target->map[i] = from->map[i];
328	}
329
330	/* Returns whether the recovery bit was actually set - it may not be
331	* if a node is still marked as needing recovery */
332	int ocfs2_recovery_map_set(struct ocfs2_super *osb,
333	int num)
334	{
335	int set = 0;
336
337	spin_lock(&osb->node_map_lock);
338
339	__ocfs2_node_map_clear_bit(&osb->mounted_map, num);
340
341	if (!test_bit(num, osb->recovery_map.map)) {
342	__ocfs2_node_map_set_bit(&osb->recovery_map, num);
343	set = 1;
344	}
345
346	spin_unlock(&osb->node_map_lock);
347
348	return set;
349	}
350
351	void ocfs2_recovery_map_clear(struct ocfs2_super *osb,
352	int num)
353	{
354	ocfs2_node_map_clear_bit(osb, &osb->recovery_map, num);
355	}
356
357	int ocfs2_node_map_iterate(struct ocfs2_super *osb,
358	struct ocfs2_node_map *map,
359	int idx)
360	{
361	int i = idx;
362
363	idx = O2NM_INVALID_NODE_NUM;
364	spin_lock(&osb->node_map_lock);
365	if ((i != O2NM_INVALID_NODE_NUM) &&
366	(i >= 0) &&
367	(i < map->num_nodes)) {
368	while(i < map->num_nodes) {
369	if (test_bit(i, map->map)) {
370	idx = i;
371	break;
372	}
373	i++;
374	}
375	}
376	spin_unlock(&osb->node_map_lock);
377	return idx;
378	}