xref: /openbmc/linux/fs/dlm/debug_fs.c (revision 54525552)
1 /******************************************************************************
2 *******************************************************************************
3 **
4 **  Copyright (C) 2005-2009 Red Hat, Inc.  All rights reserved.
5 **
6 **  This copyrighted material is made available to anyone wishing to use,
7 **  modify, copy, or redistribute it subject to the terms and conditions
8 **  of the GNU General Public License v.2.
9 **
10 *******************************************************************************
11 ******************************************************************************/
12 
13 #include <linux/pagemap.h>
14 #include <linux/seq_file.h>
15 #include <linux/module.h>
16 #include <linux/ctype.h>
17 #include <linux/debugfs.h>
18 #include <linux/slab.h>
19 
20 #include "dlm_internal.h"
21 #include "lock.h"
22 
23 #define DLM_DEBUG_BUF_LEN 4096
24 static char debug_buf[DLM_DEBUG_BUF_LEN];
25 static struct mutex debug_buf_lock;
26 
27 static struct dentry *dlm_root;
28 
29 static char *print_lockmode(int mode)
30 {
31 	switch (mode) {
32 	case DLM_LOCK_IV:
33 		return "--";
34 	case DLM_LOCK_NL:
35 		return "NL";
36 	case DLM_LOCK_CR:
37 		return "CR";
38 	case DLM_LOCK_CW:
39 		return "CW";
40 	case DLM_LOCK_PR:
41 		return "PR";
42 	case DLM_LOCK_PW:
43 		return "PW";
44 	case DLM_LOCK_EX:
45 		return "EX";
46 	default:
47 		return "??";
48 	}
49 }
50 
51 static int print_format1_lock(struct seq_file *s, struct dlm_lkb *lkb,
52 			      struct dlm_rsb *res)
53 {
54 	seq_printf(s, "%08x %s", lkb->lkb_id, print_lockmode(lkb->lkb_grmode));
55 
56 	if (lkb->lkb_status == DLM_LKSTS_CONVERT ||
57 	    lkb->lkb_status == DLM_LKSTS_WAITING)
58 		seq_printf(s, " (%s)", print_lockmode(lkb->lkb_rqmode));
59 
60 	if (lkb->lkb_nodeid) {
61 		if (lkb->lkb_nodeid != res->res_nodeid)
62 			seq_printf(s, " Remote: %3d %08x", lkb->lkb_nodeid,
63 				   lkb->lkb_remid);
64 		else
65 			seq_printf(s, " Master:     %08x", lkb->lkb_remid);
66 	}
67 
68 	if (lkb->lkb_wait_type)
69 		seq_printf(s, " wait_type: %d", lkb->lkb_wait_type);
70 
71 	return seq_printf(s, "\n");
72 }
73 
74 static int print_format1(struct dlm_rsb *res, struct seq_file *s)
75 {
76 	struct dlm_lkb *lkb;
77 	int i, lvblen = res->res_ls->ls_lvblen, recover_list, root_list;
78 	int rv;
79 
80 	lock_rsb(res);
81 
82 	rv = seq_printf(s, "\nResource %p Name (len=%d) \"",
83 			res, res->res_length);
84 	if (rv)
85 		goto out;
86 
87 	for (i = 0; i < res->res_length; i++) {
88 		if (isprint(res->res_name[i]))
89 			seq_printf(s, "%c", res->res_name[i]);
90 		else
91 			seq_printf(s, "%c", '.');
92 	}
93 
94 	if (res->res_nodeid > 0)
95 		rv = seq_printf(s, "\"  \nLocal Copy, Master is node %d\n",
96 				res->res_nodeid);
97 	else if (res->res_nodeid == 0)
98 		rv = seq_printf(s, "\"  \nMaster Copy\n");
99 	else if (res->res_nodeid == -1)
100 		rv = seq_printf(s, "\"  \nLooking up master (lkid %x)\n",
101 			   	res->res_first_lkid);
102 	else
103 		rv = seq_printf(s, "\"  \nInvalid master %d\n",
104 				res->res_nodeid);
105 	if (rv)
106 		goto out;
107 
108 	/* Print the LVB: */
109 	if (res->res_lvbptr) {
110 		seq_printf(s, "LVB: ");
111 		for (i = 0; i < lvblen; i++) {
112 			if (i == lvblen / 2)
113 				seq_printf(s, "\n     ");
114 			seq_printf(s, "%02x ",
115 				   (unsigned char) res->res_lvbptr[i]);
116 		}
117 		if (rsb_flag(res, RSB_VALNOTVALID))
118 			seq_printf(s, " (INVALID)");
119 		rv = seq_printf(s, "\n");
120 		if (rv)
121 			goto out;
122 	}
123 
124 	root_list = !list_empty(&res->res_root_list);
125 	recover_list = !list_empty(&res->res_recover_list);
126 
127 	if (root_list || recover_list) {
128 		rv = seq_printf(s, "Recovery: root %d recover %d flags %lx "
129 				"count %d\n", root_list, recover_list,
130 			   	res->res_flags, res->res_recover_locks_count);
131 		if (rv)
132 			goto out;
133 	}
134 
135 	/* Print the locks attached to this resource */
136 	seq_printf(s, "Granted Queue\n");
137 	list_for_each_entry(lkb, &res->res_grantqueue, lkb_statequeue) {
138 		rv = print_format1_lock(s, lkb, res);
139 		if (rv)
140 			goto out;
141 	}
142 
143 	seq_printf(s, "Conversion Queue\n");
144 	list_for_each_entry(lkb, &res->res_convertqueue, lkb_statequeue) {
145 		rv = print_format1_lock(s, lkb, res);
146 		if (rv)
147 			goto out;
148 	}
149 
150 	seq_printf(s, "Waiting Queue\n");
151 	list_for_each_entry(lkb, &res->res_waitqueue, lkb_statequeue) {
152 		rv = print_format1_lock(s, lkb, res);
153 		if (rv)
154 			goto out;
155 	}
156 
157 	if (list_empty(&res->res_lookup))
158 		goto out;
159 
160 	seq_printf(s, "Lookup Queue\n");
161 	list_for_each_entry(lkb, &res->res_lookup, lkb_rsb_lookup) {
162 		rv = seq_printf(s, "%08x %s", lkb->lkb_id,
163 				print_lockmode(lkb->lkb_rqmode));
164 		if (lkb->lkb_wait_type)
165 			seq_printf(s, " wait_type: %d", lkb->lkb_wait_type);
166 		rv = seq_printf(s, "\n");
167 	}
168  out:
169 	unlock_rsb(res);
170 	return rv;
171 }
172 
173 static int print_format2_lock(struct seq_file *s, struct dlm_lkb *lkb,
174 			      struct dlm_rsb *r)
175 {
176 	u64 xid = 0;
177 	u64 us;
178 	int rv;
179 
180 	if (lkb->lkb_flags & DLM_IFL_USER) {
181 		if (lkb->lkb_ua)
182 			xid = lkb->lkb_ua->xid;
183 	}
184 
185 	/* microseconds since lkb was added to current queue */
186 	us = ktime_to_us(ktime_sub(ktime_get(), lkb->lkb_timestamp));
187 
188 	/* id nodeid remid pid xid exflags flags sts grmode rqmode time_us
189 	   r_nodeid r_len r_name */
190 
191 	rv = seq_printf(s, "%x %d %x %u %llu %x %x %d %d %d %llu %u %d \"%s\"\n",
192 			lkb->lkb_id,
193 			lkb->lkb_nodeid,
194 			lkb->lkb_remid,
195 			lkb->lkb_ownpid,
196 			(unsigned long long)xid,
197 			lkb->lkb_exflags,
198 			lkb->lkb_flags,
199 			lkb->lkb_status,
200 			lkb->lkb_grmode,
201 			lkb->lkb_rqmode,
202 			(unsigned long long)us,
203 			r->res_nodeid,
204 			r->res_length,
205 			r->res_name);
206 	return rv;
207 }
208 
209 static int print_format2(struct dlm_rsb *r, struct seq_file *s)
210 {
211 	struct dlm_lkb *lkb;
212 	int rv = 0;
213 
214 	lock_rsb(r);
215 
216 	list_for_each_entry(lkb, &r->res_grantqueue, lkb_statequeue) {
217 		rv = print_format2_lock(s, lkb, r);
218 		if (rv)
219 			goto out;
220 	}
221 
222 	list_for_each_entry(lkb, &r->res_convertqueue, lkb_statequeue) {
223 		rv = print_format2_lock(s, lkb, r);
224 		if (rv)
225 			goto out;
226 	}
227 
228 	list_for_each_entry(lkb, &r->res_waitqueue, lkb_statequeue) {
229 		rv = print_format2_lock(s, lkb, r);
230 		if (rv)
231 			goto out;
232 	}
233  out:
234 	unlock_rsb(r);
235 	return rv;
236 }
237 
238 static int print_format3_lock(struct seq_file *s, struct dlm_lkb *lkb,
239 			      int rsb_lookup)
240 {
241 	u64 xid = 0;
242 	int rv;
243 
244 	if (lkb->lkb_flags & DLM_IFL_USER) {
245 		if (lkb->lkb_ua)
246 			xid = lkb->lkb_ua->xid;
247 	}
248 
249 	rv = seq_printf(s, "lkb %x %d %x %u %llu %x %x %d %d %d %d %d %d %u %llu %llu\n",
250 			lkb->lkb_id,
251 			lkb->lkb_nodeid,
252 			lkb->lkb_remid,
253 			lkb->lkb_ownpid,
254 			(unsigned long long)xid,
255 			lkb->lkb_exflags,
256 			lkb->lkb_flags,
257 			lkb->lkb_status,
258 			lkb->lkb_grmode,
259 			lkb->lkb_rqmode,
260 			lkb->lkb_last_bast.mode,
261 			rsb_lookup,
262 			lkb->lkb_wait_type,
263 			lkb->lkb_lvbseq,
264 			(unsigned long long)ktime_to_ns(lkb->lkb_timestamp),
265 			(unsigned long long)ktime_to_ns(lkb->lkb_last_bast_time));
266 	return rv;
267 }
268 
269 static int print_format3(struct dlm_rsb *r, struct seq_file *s)
270 {
271 	struct dlm_lkb *lkb;
272 	int i, lvblen = r->res_ls->ls_lvblen;
273 	int print_name = 1;
274 	int rv;
275 
276 	lock_rsb(r);
277 
278 	rv = seq_printf(s, "rsb %p %d %x %lx %d %d %u %d ",
279 			r,
280 			r->res_nodeid,
281 			r->res_first_lkid,
282 			r->res_flags,
283 			!list_empty(&r->res_root_list),
284 			!list_empty(&r->res_recover_list),
285 			r->res_recover_locks_count,
286 			r->res_length);
287 	if (rv)
288 		goto out;
289 
290 	for (i = 0; i < r->res_length; i++) {
291 		if (!isascii(r->res_name[i]) || !isprint(r->res_name[i]))
292 			print_name = 0;
293 	}
294 
295 	seq_printf(s, "%s", print_name ? "str " : "hex");
296 
297 	for (i = 0; i < r->res_length; i++) {
298 		if (print_name)
299 			seq_printf(s, "%c", r->res_name[i]);
300 		else
301 			seq_printf(s, " %02x", (unsigned char)r->res_name[i]);
302 	}
303 	rv = seq_printf(s, "\n");
304 	if (rv)
305 		goto out;
306 
307 	if (!r->res_lvbptr)
308 		goto do_locks;
309 
310 	seq_printf(s, "lvb %u %d", r->res_lvbseq, lvblen);
311 
312 	for (i = 0; i < lvblen; i++)
313 		seq_printf(s, " %02x", (unsigned char)r->res_lvbptr[i]);
314 	rv = seq_printf(s, "\n");
315 	if (rv)
316 		goto out;
317 
318  do_locks:
319 	list_for_each_entry(lkb, &r->res_grantqueue, lkb_statequeue) {
320 		rv = print_format3_lock(s, lkb, 0);
321 		if (rv)
322 			goto out;
323 	}
324 
325 	list_for_each_entry(lkb, &r->res_convertqueue, lkb_statequeue) {
326 		rv = print_format3_lock(s, lkb, 0);
327 		if (rv)
328 			goto out;
329 	}
330 
331 	list_for_each_entry(lkb, &r->res_waitqueue, lkb_statequeue) {
332 		rv = print_format3_lock(s, lkb, 0);
333 		if (rv)
334 			goto out;
335 	}
336 
337 	list_for_each_entry(lkb, &r->res_lookup, lkb_rsb_lookup) {
338 		rv = print_format3_lock(s, lkb, 1);
339 		if (rv)
340 			goto out;
341 	}
342  out:
343 	unlock_rsb(r);
344 	return rv;
345 }
346 
347 struct rsbtbl_iter {
348 	struct dlm_rsb *rsb;
349 	unsigned bucket;
350 	int format;
351 	int header;
352 };
353 
354 /* seq_printf returns -1 if the buffer is full, and 0 otherwise.
355    If the buffer is full, seq_printf can be called again, but it
356    does nothing and just returns -1.  So, the these printing routines
357    periodically check the return value to avoid wasting too much time
358    trying to print to a full buffer. */
359 
360 static int table_seq_show(struct seq_file *seq, void *iter_ptr)
361 {
362 	struct rsbtbl_iter *ri = iter_ptr;
363 	int rv = 0;
364 
365 	switch (ri->format) {
366 	case 1:
367 		rv = print_format1(ri->rsb, seq);
368 		break;
369 	case 2:
370 		if (ri->header) {
371 			seq_printf(seq, "id nodeid remid pid xid exflags "
372 					"flags sts grmode rqmode time_ms "
373 					"r_nodeid r_len r_name\n");
374 			ri->header = 0;
375 		}
376 		rv = print_format2(ri->rsb, seq);
377 		break;
378 	case 3:
379 		if (ri->header) {
380 			seq_printf(seq, "version rsb 1.1 lvb 1.1 lkb 1.1\n");
381 			ri->header = 0;
382 		}
383 		rv = print_format3(ri->rsb, seq);
384 		break;
385 	}
386 
387 	return rv;
388 }
389 
390 static const struct seq_operations format1_seq_ops;
391 static const struct seq_operations format2_seq_ops;
392 static const struct seq_operations format3_seq_ops;
393 
394 static void *table_seq_start(struct seq_file *seq, loff_t *pos)
395 {
396 	struct dlm_ls *ls = seq->private;
397 	struct rsbtbl_iter *ri;
398 	struct dlm_rsb *r;
399 	loff_t n = *pos;
400 	unsigned bucket, entry;
401 
402 	bucket = n >> 32;
403 	entry = n & ((1LL << 32) - 1);
404 
405 	if (bucket >= ls->ls_rsbtbl_size)
406 		return NULL;
407 
408 	ri = kzalloc(sizeof(struct rsbtbl_iter), GFP_NOFS);
409 	if (!ri)
410 		return NULL;
411 	if (n == 0)
412 		ri->header = 1;
413 	if (seq->op == &format1_seq_ops)
414 		ri->format = 1;
415 	if (seq->op == &format2_seq_ops)
416 		ri->format = 2;
417 	if (seq->op == &format3_seq_ops)
418 		ri->format = 3;
419 
420 	spin_lock(&ls->ls_rsbtbl[bucket].lock);
421 	if (!list_empty(&ls->ls_rsbtbl[bucket].list)) {
422 		list_for_each_entry(r, &ls->ls_rsbtbl[bucket].list,
423 				    res_hashchain) {
424 			if (!entry--) {
425 				dlm_hold_rsb(r);
426 				ri->rsb = r;
427 				ri->bucket = bucket;
428 				spin_unlock(&ls->ls_rsbtbl[bucket].lock);
429 				return ri;
430 			}
431 		}
432 	}
433 	spin_unlock(&ls->ls_rsbtbl[bucket].lock);
434 
435 	/*
436 	 * move to the first rsb in the next non-empty bucket
437 	 */
438 
439 	/* zero the entry */
440 	n &= ~((1LL << 32) - 1);
441 
442 	while (1) {
443 		bucket++;
444 		n += 1LL << 32;
445 
446 		if (bucket >= ls->ls_rsbtbl_size) {
447 			kfree(ri);
448 			return NULL;
449 		}
450 
451 		spin_lock(&ls->ls_rsbtbl[bucket].lock);
452 		if (!list_empty(&ls->ls_rsbtbl[bucket].list)) {
453 			r = list_first_entry(&ls->ls_rsbtbl[bucket].list,
454 					     struct dlm_rsb, res_hashchain);
455 			dlm_hold_rsb(r);
456 			ri->rsb = r;
457 			ri->bucket = bucket;
458 			spin_unlock(&ls->ls_rsbtbl[bucket].lock);
459 			*pos = n;
460 			return ri;
461 		}
462 		spin_unlock(&ls->ls_rsbtbl[bucket].lock);
463 	}
464 }
465 
466 static void *table_seq_next(struct seq_file *seq, void *iter_ptr, loff_t *pos)
467 {
468 	struct dlm_ls *ls = seq->private;
469 	struct rsbtbl_iter *ri = iter_ptr;
470 	struct list_head *next;
471 	struct dlm_rsb *r, *rp;
472 	loff_t n = *pos;
473 	unsigned bucket;
474 
475 	bucket = n >> 32;
476 
477 	/*
478 	 * move to the next rsb in the same bucket
479 	 */
480 
481 	spin_lock(&ls->ls_rsbtbl[bucket].lock);
482 	rp = ri->rsb;
483 	next = rp->res_hashchain.next;
484 
485 	if (next != &ls->ls_rsbtbl[bucket].list) {
486 		r = list_entry(next, struct dlm_rsb, res_hashchain);
487 		dlm_hold_rsb(r);
488 		ri->rsb = r;
489 		spin_unlock(&ls->ls_rsbtbl[bucket].lock);
490 		dlm_put_rsb(rp);
491 		++*pos;
492 		return ri;
493 	}
494 	spin_unlock(&ls->ls_rsbtbl[bucket].lock);
495 	dlm_put_rsb(rp);
496 
497 	/*
498 	 * move to the first rsb in the next non-empty bucket
499 	 */
500 
501 	/* zero the entry */
502 	n &= ~((1LL << 32) - 1);
503 
504 	while (1) {
505 		bucket++;
506 		n += 1LL << 32;
507 
508 		if (bucket >= ls->ls_rsbtbl_size) {
509 			kfree(ri);
510 			return NULL;
511 		}
512 
513 		spin_lock(&ls->ls_rsbtbl[bucket].lock);
514 		if (!list_empty(&ls->ls_rsbtbl[bucket].list)) {
515 			r = list_first_entry(&ls->ls_rsbtbl[bucket].list,
516 					     struct dlm_rsb, res_hashchain);
517 			dlm_hold_rsb(r);
518 			ri->rsb = r;
519 			ri->bucket = bucket;
520 			spin_unlock(&ls->ls_rsbtbl[bucket].lock);
521 			*pos = n;
522 			return ri;
523 		}
524 		spin_unlock(&ls->ls_rsbtbl[bucket].lock);
525 	}
526 }
527 
528 static void table_seq_stop(struct seq_file *seq, void *iter_ptr)
529 {
530 	struct rsbtbl_iter *ri = iter_ptr;
531 
532 	if (ri) {
533 		dlm_put_rsb(ri->rsb);
534 		kfree(ri);
535 	}
536 }
537 
538 static const struct seq_operations format1_seq_ops = {
539 	.start = table_seq_start,
540 	.next  = table_seq_next,
541 	.stop  = table_seq_stop,
542 	.show  = table_seq_show,
543 };
544 
545 static const struct seq_operations format2_seq_ops = {
546 	.start = table_seq_start,
547 	.next  = table_seq_next,
548 	.stop  = table_seq_stop,
549 	.show  = table_seq_show,
550 };
551 
552 static const struct seq_operations format3_seq_ops = {
553 	.start = table_seq_start,
554 	.next  = table_seq_next,
555 	.stop  = table_seq_stop,
556 	.show  = table_seq_show,
557 };
558 
559 static const struct file_operations format1_fops;
560 static const struct file_operations format2_fops;
561 static const struct file_operations format3_fops;
562 
563 static int table_open(struct inode *inode, struct file *file)
564 {
565 	struct seq_file *seq;
566 	int ret = -1;
567 
568 	if (file->f_op == &format1_fops)
569 		ret = seq_open(file, &format1_seq_ops);
570 	else if (file->f_op == &format2_fops)
571 		ret = seq_open(file, &format2_seq_ops);
572 	else if (file->f_op == &format3_fops)
573 		ret = seq_open(file, &format3_seq_ops);
574 
575 	if (ret)
576 		return ret;
577 
578 	seq = file->private_data;
579 	seq->private = inode->i_private; /* the dlm_ls */
580 	return 0;
581 }
582 
583 static const struct file_operations format1_fops = {
584 	.owner   = THIS_MODULE,
585 	.open    = table_open,
586 	.read    = seq_read,
587 	.llseek  = seq_lseek,
588 	.release = seq_release
589 };
590 
591 static const struct file_operations format2_fops = {
592 	.owner   = THIS_MODULE,
593 	.open    = table_open,
594 	.read    = seq_read,
595 	.llseek  = seq_lseek,
596 	.release = seq_release
597 };
598 
599 static const struct file_operations format3_fops = {
600 	.owner   = THIS_MODULE,
601 	.open    = table_open,
602 	.read    = seq_read,
603 	.llseek  = seq_lseek,
604 	.release = seq_release
605 };
606 
607 /*
608  * dump lkb's on the ls_waiters list
609  */
610 
611 static int waiters_open(struct inode *inode, struct file *file)
612 {
613 	file->private_data = inode->i_private;
614 	return 0;
615 }
616 
617 static ssize_t waiters_read(struct file *file, char __user *userbuf,
618 			    size_t count, loff_t *ppos)
619 {
620 	struct dlm_ls *ls = file->private_data;
621 	struct dlm_lkb *lkb;
622 	size_t len = DLM_DEBUG_BUF_LEN, pos = 0, ret, rv;
623 
624 	mutex_lock(&debug_buf_lock);
625 	mutex_lock(&ls->ls_waiters_mutex);
626 	memset(debug_buf, 0, sizeof(debug_buf));
627 
628 	list_for_each_entry(lkb, &ls->ls_waiters, lkb_wait_reply) {
629 		ret = snprintf(debug_buf + pos, len - pos, "%x %d %d %s\n",
630 			       lkb->lkb_id, lkb->lkb_wait_type,
631 			       lkb->lkb_nodeid, lkb->lkb_resource->res_name);
632 		if (ret >= len - pos)
633 			break;
634 		pos += ret;
635 	}
636 	mutex_unlock(&ls->ls_waiters_mutex);
637 
638 	rv = simple_read_from_buffer(userbuf, count, ppos, debug_buf, pos);
639 	mutex_unlock(&debug_buf_lock);
640 	return rv;
641 }
642 
643 static const struct file_operations waiters_fops = {
644 	.owner   = THIS_MODULE,
645 	.open    = waiters_open,
646 	.read    = waiters_read,
647 	.llseek  = default_llseek,
648 };
649 
650 void dlm_delete_debug_file(struct dlm_ls *ls)
651 {
652 	if (ls->ls_debug_rsb_dentry)
653 		debugfs_remove(ls->ls_debug_rsb_dentry);
654 	if (ls->ls_debug_waiters_dentry)
655 		debugfs_remove(ls->ls_debug_waiters_dentry);
656 	if (ls->ls_debug_locks_dentry)
657 		debugfs_remove(ls->ls_debug_locks_dentry);
658 	if (ls->ls_debug_all_dentry)
659 		debugfs_remove(ls->ls_debug_all_dentry);
660 }
661 
662 int dlm_create_debug_file(struct dlm_ls *ls)
663 {
664 	char name[DLM_LOCKSPACE_LEN+8];
665 
666 	/* format 1 */
667 
668 	ls->ls_debug_rsb_dentry = debugfs_create_file(ls->ls_name,
669 						      S_IFREG | S_IRUGO,
670 						      dlm_root,
671 						      ls,
672 						      &format1_fops);
673 	if (!ls->ls_debug_rsb_dentry)
674 		goto fail;
675 
676 	/* format 2 */
677 
678 	memset(name, 0, sizeof(name));
679 	snprintf(name, DLM_LOCKSPACE_LEN+8, "%s_locks", ls->ls_name);
680 
681 	ls->ls_debug_locks_dentry = debugfs_create_file(name,
682 							S_IFREG | S_IRUGO,
683 							dlm_root,
684 							ls,
685 							&format2_fops);
686 	if (!ls->ls_debug_locks_dentry)
687 		goto fail;
688 
689 	/* format 3 */
690 
691 	memset(name, 0, sizeof(name));
692 	snprintf(name, DLM_LOCKSPACE_LEN+8, "%s_all", ls->ls_name);
693 
694 	ls->ls_debug_all_dentry = debugfs_create_file(name,
695 						      S_IFREG | S_IRUGO,
696 						      dlm_root,
697 						      ls,
698 						      &format3_fops);
699 	if (!ls->ls_debug_all_dentry)
700 		goto fail;
701 
702 	memset(name, 0, sizeof(name));
703 	snprintf(name, DLM_LOCKSPACE_LEN+8, "%s_waiters", ls->ls_name);
704 
705 	ls->ls_debug_waiters_dentry = debugfs_create_file(name,
706 							  S_IFREG | S_IRUGO,
707 							  dlm_root,
708 							  ls,
709 							  &waiters_fops);
710 	if (!ls->ls_debug_waiters_dentry)
711 		goto fail;
712 
713 	return 0;
714 
715  fail:
716 	dlm_delete_debug_file(ls);
717 	return -ENOMEM;
718 }
719 
720 int __init dlm_register_debugfs(void)
721 {
722 	mutex_init(&debug_buf_lock);
723 	dlm_root = debugfs_create_dir("dlm", NULL);
724 	return dlm_root ? 0 : -ENOMEM;
725 }
726 
727 void dlm_unregister_debugfs(void)
728 {
729 	debugfs_remove(dlm_root);
730 }
731 
732