xref: /openbmc/linux/fs/dlm/debug_fs.c (revision b627b4ed)
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 
19 #include "dlm_internal.h"
20 #include "lock.h"
21 
22 #define DLM_DEBUG_BUF_LEN 4096
23 static char debug_buf[DLM_DEBUG_BUF_LEN];
24 static struct mutex debug_buf_lock;
25 
26 static struct dentry *dlm_root;
27 
28 static char *print_lockmode(int mode)
29 {
30 	switch (mode) {
31 	case DLM_LOCK_IV:
32 		return "--";
33 	case DLM_LOCK_NL:
34 		return "NL";
35 	case DLM_LOCK_CR:
36 		return "CR";
37 	case DLM_LOCK_CW:
38 		return "CW";
39 	case DLM_LOCK_PR:
40 		return "PR";
41 	case DLM_LOCK_PW:
42 		return "PW";
43 	case DLM_LOCK_EX:
44 		return "EX";
45 	default:
46 		return "??";
47 	}
48 }
49 
50 static int print_format1_lock(struct seq_file *s, struct dlm_lkb *lkb,
51 			      struct dlm_rsb *res)
52 {
53 	seq_printf(s, "%08x %s", lkb->lkb_id, print_lockmode(lkb->lkb_grmode));
54 
55 	if (lkb->lkb_status == DLM_LKSTS_CONVERT ||
56 	    lkb->lkb_status == DLM_LKSTS_WAITING)
57 		seq_printf(s, " (%s)", print_lockmode(lkb->lkb_rqmode));
58 
59 	if (lkb->lkb_nodeid) {
60 		if (lkb->lkb_nodeid != res->res_nodeid)
61 			seq_printf(s, " Remote: %3d %08x", lkb->lkb_nodeid,
62 				   lkb->lkb_remid);
63 		else
64 			seq_printf(s, " Master:     %08x", lkb->lkb_remid);
65 	}
66 
67 	if (lkb->lkb_wait_type)
68 		seq_printf(s, " wait_type: %d", lkb->lkb_wait_type);
69 
70 	return seq_printf(s, "\n");
71 }
72 
73 static int print_format1(struct dlm_rsb *res, struct seq_file *s)
74 {
75 	struct dlm_lkb *lkb;
76 	int i, lvblen = res->res_ls->ls_lvblen, recover_list, root_list;
77 	int rv;
78 
79 	lock_rsb(res);
80 
81 	rv = seq_printf(s, "\nResource %p Name (len=%d) \"",
82 			res, res->res_length);
83 	if (rv)
84 		goto out;
85 
86 	for (i = 0; i < res->res_length; i++) {
87 		if (isprint(res->res_name[i]))
88 			seq_printf(s, "%c", res->res_name[i]);
89 		else
90 			seq_printf(s, "%c", '.');
91 	}
92 
93 	if (res->res_nodeid > 0)
94 		rv = seq_printf(s, "\"  \nLocal Copy, Master is node %d\n",
95 				res->res_nodeid);
96 	else if (res->res_nodeid == 0)
97 		rv = seq_printf(s, "\"  \nMaster Copy\n");
98 	else if (res->res_nodeid == -1)
99 		rv = seq_printf(s, "\"  \nLooking up master (lkid %x)\n",
100 			   	res->res_first_lkid);
101 	else
102 		rv = seq_printf(s, "\"  \nInvalid master %d\n",
103 				res->res_nodeid);
104 	if (rv)
105 		goto out;
106 
107 	/* Print the LVB: */
108 	if (res->res_lvbptr) {
109 		seq_printf(s, "LVB: ");
110 		for (i = 0; i < lvblen; i++) {
111 			if (i == lvblen / 2)
112 				seq_printf(s, "\n     ");
113 			seq_printf(s, "%02x ",
114 				   (unsigned char) res->res_lvbptr[i]);
115 		}
116 		if (rsb_flag(res, RSB_VALNOTVALID))
117 			seq_printf(s, " (INVALID)");
118 		rv = seq_printf(s, "\n");
119 		if (rv)
120 			goto out;
121 	}
122 
123 	root_list = !list_empty(&res->res_root_list);
124 	recover_list = !list_empty(&res->res_recover_list);
125 
126 	if (root_list || recover_list) {
127 		rv = seq_printf(s, "Recovery: root %d recover %d flags %lx "
128 				"count %d\n", root_list, recover_list,
129 			   	res->res_flags, res->res_recover_locks_count);
130 		if (rv)
131 			goto out;
132 	}
133 
134 	/* Print the locks attached to this resource */
135 	seq_printf(s, "Granted Queue\n");
136 	list_for_each_entry(lkb, &res->res_grantqueue, lkb_statequeue) {
137 		rv = print_format1_lock(s, lkb, res);
138 		if (rv)
139 			goto out;
140 	}
141 
142 	seq_printf(s, "Conversion Queue\n");
143 	list_for_each_entry(lkb, &res->res_convertqueue, lkb_statequeue) {
144 		rv = print_format1_lock(s, lkb, res);
145 		if (rv)
146 			goto out;
147 	}
148 
149 	seq_printf(s, "Waiting Queue\n");
150 	list_for_each_entry(lkb, &res->res_waitqueue, lkb_statequeue) {
151 		rv = print_format1_lock(s, lkb, res);
152 		if (rv)
153 			goto out;
154 	}
155 
156 	if (list_empty(&res->res_lookup))
157 		goto out;
158 
159 	seq_printf(s, "Lookup Queue\n");
160 	list_for_each_entry(lkb, &res->res_lookup, lkb_rsb_lookup) {
161 		rv = seq_printf(s, "%08x %s", lkb->lkb_id,
162 				print_lockmode(lkb->lkb_rqmode));
163 		if (lkb->lkb_wait_type)
164 			seq_printf(s, " wait_type: %d", lkb->lkb_wait_type);
165 		rv = seq_printf(s, "\n");
166 	}
167  out:
168 	unlock_rsb(res);
169 	return rv;
170 }
171 
172 static int print_format2_lock(struct seq_file *s, struct dlm_lkb *lkb,
173 			      struct dlm_rsb *r)
174 {
175 	u64 xid = 0;
176 	u64 us;
177 	int rv;
178 
179 	if (lkb->lkb_flags & DLM_IFL_USER) {
180 		if (lkb->lkb_ua)
181 			xid = lkb->lkb_ua->xid;
182 	}
183 
184 	/* microseconds since lkb was added to current queue */
185 	us = ktime_to_us(ktime_sub(ktime_get(), lkb->lkb_timestamp));
186 
187 	/* id nodeid remid pid xid exflags flags sts grmode rqmode time_us
188 	   r_nodeid r_len r_name */
189 
190 	rv = seq_printf(s, "%x %d %x %u %llu %x %x %d %d %d %llu %u %d \"%s\"\n",
191 			lkb->lkb_id,
192 			lkb->lkb_nodeid,
193 			lkb->lkb_remid,
194 			lkb->lkb_ownpid,
195 			(unsigned long long)xid,
196 			lkb->lkb_exflags,
197 			lkb->lkb_flags,
198 			lkb->lkb_status,
199 			lkb->lkb_grmode,
200 			lkb->lkb_rqmode,
201 			(unsigned long long)us,
202 			r->res_nodeid,
203 			r->res_length,
204 			r->res_name);
205 	return rv;
206 }
207 
208 static int print_format2(struct dlm_rsb *r, struct seq_file *s)
209 {
210 	struct dlm_lkb *lkb;
211 	int rv = 0;
212 
213 	lock_rsb(r);
214 
215 	list_for_each_entry(lkb, &r->res_grantqueue, lkb_statequeue) {
216 		rv = print_format2_lock(s, lkb, r);
217 		if (rv)
218 			goto out;
219 	}
220 
221 	list_for_each_entry(lkb, &r->res_convertqueue, lkb_statequeue) {
222 		rv = print_format2_lock(s, lkb, r);
223 		if (rv)
224 			goto out;
225 	}
226 
227 	list_for_each_entry(lkb, &r->res_waitqueue, lkb_statequeue) {
228 		rv = print_format2_lock(s, lkb, r);
229 		if (rv)
230 			goto out;
231 	}
232  out:
233 	unlock_rsb(r);
234 	return rv;
235 }
236 
237 static int print_format3_lock(struct seq_file *s, struct dlm_lkb *lkb,
238 			      int rsb_lookup)
239 {
240 	u64 xid = 0;
241 	int rv;
242 
243 	if (lkb->lkb_flags & DLM_IFL_USER) {
244 		if (lkb->lkb_ua)
245 			xid = lkb->lkb_ua->xid;
246 	}
247 
248 	rv = seq_printf(s, "lkb %x %d %x %u %llu %x %x %d %d %d %d %d %d %u %llu %llu\n",
249 			lkb->lkb_id,
250 			lkb->lkb_nodeid,
251 			lkb->lkb_remid,
252 			lkb->lkb_ownpid,
253 			(unsigned long long)xid,
254 			lkb->lkb_exflags,
255 			lkb->lkb_flags,
256 			lkb->lkb_status,
257 			lkb->lkb_grmode,
258 			lkb->lkb_rqmode,
259 			lkb->lkb_highbast,
260 			rsb_lookup,
261 			lkb->lkb_wait_type,
262 			lkb->lkb_lvbseq,
263 			(unsigned long long)ktime_to_ns(lkb->lkb_timestamp),
264 			(unsigned long long)ktime_to_ns(lkb->lkb_time_bast));
265 	return rv;
266 }
267 
268 static int print_format3(struct dlm_rsb *r, struct seq_file *s)
269 {
270 	struct dlm_lkb *lkb;
271 	int i, lvblen = r->res_ls->ls_lvblen;
272 	int print_name = 1;
273 	int rv;
274 
275 	lock_rsb(r);
276 
277 	rv = seq_printf(s, "rsb %p %d %x %lx %d %d %u %d ",
278 			r,
279 			r->res_nodeid,
280 			r->res_first_lkid,
281 			r->res_flags,
282 			!list_empty(&r->res_root_list),
283 			!list_empty(&r->res_recover_list),
284 			r->res_recover_locks_count,
285 			r->res_length);
286 	if (rv)
287 		goto out;
288 
289 	for (i = 0; i < r->res_length; i++) {
290 		if (!isascii(r->res_name[i]) || !isprint(r->res_name[i]))
291 			print_name = 0;
292 	}
293 
294 	seq_printf(s, "%s", print_name ? "str " : "hex");
295 
296 	for (i = 0; i < r->res_length; i++) {
297 		if (print_name)
298 			seq_printf(s, "%c", r->res_name[i]);
299 		else
300 			seq_printf(s, " %02x", (unsigned char)r->res_name[i]);
301 	}
302 	rv = seq_printf(s, "\n");
303 	if (rv)
304 		goto out;
305 
306 	if (!r->res_lvbptr)
307 		goto do_locks;
308 
309 	seq_printf(s, "lvb %u %d", r->res_lvbseq, lvblen);
310 
311 	for (i = 0; i < lvblen; i++)
312 		seq_printf(s, " %02x", (unsigned char)r->res_lvbptr[i]);
313 	rv = seq_printf(s, "\n");
314 	if (rv)
315 		goto out;
316 
317  do_locks:
318 	list_for_each_entry(lkb, &r->res_grantqueue, lkb_statequeue) {
319 		rv = print_format3_lock(s, lkb, 0);
320 		if (rv)
321 			goto out;
322 	}
323 
324 	list_for_each_entry(lkb, &r->res_convertqueue, lkb_statequeue) {
325 		rv = print_format3_lock(s, lkb, 0);
326 		if (rv)
327 			goto out;
328 	}
329 
330 	list_for_each_entry(lkb, &r->res_waitqueue, lkb_statequeue) {
331 		rv = print_format3_lock(s, lkb, 0);
332 		if (rv)
333 			goto out;
334 	}
335 
336 	list_for_each_entry(lkb, &r->res_lookup, lkb_rsb_lookup) {
337 		rv = print_format3_lock(s, lkb, 1);
338 		if (rv)
339 			goto out;
340 	}
341  out:
342 	unlock_rsb(r);
343 	return rv;
344 }
345 
346 struct rsbtbl_iter {
347 	struct dlm_rsb *rsb;
348 	unsigned bucket;
349 	int format;
350 	int header;
351 };
352 
353 /* seq_printf returns -1 if the buffer is full, and 0 otherwise.
354    If the buffer is full, seq_printf can be called again, but it
355    does nothing and just returns -1.  So, the these printing routines
356    periodically check the return value to avoid wasting too much time
357    trying to print to a full buffer. */
358 
359 static int table_seq_show(struct seq_file *seq, void *iter_ptr)
360 {
361 	struct rsbtbl_iter *ri = iter_ptr;
362 	int rv = 0;
363 
364 	switch (ri->format) {
365 	case 1:
366 		rv = print_format1(ri->rsb, seq);
367 		break;
368 	case 2:
369 		if (ri->header) {
370 			seq_printf(seq, "id nodeid remid pid xid exflags "
371 					"flags sts grmode rqmode time_ms "
372 					"r_nodeid r_len r_name\n");
373 			ri->header = 0;
374 		}
375 		rv = print_format2(ri->rsb, seq);
376 		break;
377 	case 3:
378 		if (ri->header) {
379 			seq_printf(seq, "version rsb 1.1 lvb 1.1 lkb 1.1\n");
380 			ri->header = 0;
381 		}
382 		rv = print_format3(ri->rsb, seq);
383 		break;
384 	}
385 
386 	return rv;
387 }
388 
389 static struct seq_operations format1_seq_ops;
390 static struct seq_operations format2_seq_ops;
391 static struct seq_operations format3_seq_ops;
392 
393 static void *table_seq_start(struct seq_file *seq, loff_t *pos)
394 {
395 	struct dlm_ls *ls = seq->private;
396 	struct rsbtbl_iter *ri;
397 	struct dlm_rsb *r;
398 	loff_t n = *pos;
399 	unsigned bucket, entry;
400 
401 	bucket = n >> 32;
402 	entry = n & ((1LL << 32) - 1);
403 
404 	if (bucket >= ls->ls_rsbtbl_size)
405 		return NULL;
406 
407 	ri = kzalloc(sizeof(struct rsbtbl_iter), GFP_KERNEL);
408 	if (!ri)
409 		return NULL;
410 	if (n == 0)
411 		ri->header = 1;
412 	if (seq->op == &format1_seq_ops)
413 		ri->format = 1;
414 	if (seq->op == &format2_seq_ops)
415 		ri->format = 2;
416 	if (seq->op == &format3_seq_ops)
417 		ri->format = 3;
418 
419 	spin_lock(&ls->ls_rsbtbl[bucket].lock);
420 	if (!list_empty(&ls->ls_rsbtbl[bucket].list)) {
421 		list_for_each_entry(r, &ls->ls_rsbtbl[bucket].list,
422 				    res_hashchain) {
423 			if (!entry--) {
424 				dlm_hold_rsb(r);
425 				ri->rsb = r;
426 				ri->bucket = bucket;
427 				spin_unlock(&ls->ls_rsbtbl[bucket].lock);
428 				return ri;
429 			}
430 		}
431 	}
432 	spin_unlock(&ls->ls_rsbtbl[bucket].lock);
433 
434 	/*
435 	 * move to the first rsb in the next non-empty bucket
436 	 */
437 
438 	/* zero the entry */
439 	n &= ~((1LL << 32) - 1);
440 
441 	while (1) {
442 		bucket++;
443 		n += 1LL << 32;
444 
445 		if (bucket >= ls->ls_rsbtbl_size) {
446 			kfree(ri);
447 			return NULL;
448 		}
449 
450 		spin_lock(&ls->ls_rsbtbl[bucket].lock);
451 		if (!list_empty(&ls->ls_rsbtbl[bucket].list)) {
452 			r = list_first_entry(&ls->ls_rsbtbl[bucket].list,
453 					     struct dlm_rsb, res_hashchain);
454 			dlm_hold_rsb(r);
455 			ri->rsb = r;
456 			ri->bucket = bucket;
457 			spin_unlock(&ls->ls_rsbtbl[bucket].lock);
458 			*pos = n;
459 			return ri;
460 		}
461 		spin_unlock(&ls->ls_rsbtbl[bucket].lock);
462 	}
463 }
464 
465 static void *table_seq_next(struct seq_file *seq, void *iter_ptr, loff_t *pos)
466 {
467 	struct dlm_ls *ls = seq->private;
468 	struct rsbtbl_iter *ri = iter_ptr;
469 	struct list_head *next;
470 	struct dlm_rsb *r, *rp;
471 	loff_t n = *pos;
472 	unsigned bucket;
473 
474 	bucket = n >> 32;
475 
476 	/*
477 	 * move to the next rsb in the same bucket
478 	 */
479 
480 	spin_lock(&ls->ls_rsbtbl[bucket].lock);
481 	rp = ri->rsb;
482 	next = rp->res_hashchain.next;
483 
484 	if (next != &ls->ls_rsbtbl[bucket].list) {
485 		r = list_entry(next, struct dlm_rsb, res_hashchain);
486 		dlm_hold_rsb(r);
487 		ri->rsb = r;
488 		spin_unlock(&ls->ls_rsbtbl[bucket].lock);
489 		dlm_put_rsb(rp);
490 		++*pos;
491 		return ri;
492 	}
493 	spin_unlock(&ls->ls_rsbtbl[bucket].lock);
494 	dlm_put_rsb(rp);
495 
496 	/*
497 	 * move to the first rsb in the next non-empty bucket
498 	 */
499 
500 	/* zero the entry */
501 	n &= ~((1LL << 32) - 1);
502 
503 	while (1) {
504 		bucket++;
505 		n += 1LL << 32;
506 
507 		if (bucket >= ls->ls_rsbtbl_size) {
508 			kfree(ri);
509 			return NULL;
510 		}
511 
512 		spin_lock(&ls->ls_rsbtbl[bucket].lock);
513 		if (!list_empty(&ls->ls_rsbtbl[bucket].list)) {
514 			r = list_first_entry(&ls->ls_rsbtbl[bucket].list,
515 					     struct dlm_rsb, res_hashchain);
516 			dlm_hold_rsb(r);
517 			ri->rsb = r;
518 			ri->bucket = bucket;
519 			spin_unlock(&ls->ls_rsbtbl[bucket].lock);
520 			*pos = n;
521 			return ri;
522 		}
523 		spin_unlock(&ls->ls_rsbtbl[bucket].lock);
524 	}
525 }
526 
527 static void table_seq_stop(struct seq_file *seq, void *iter_ptr)
528 {
529 	struct rsbtbl_iter *ri = iter_ptr;
530 
531 	if (ri) {
532 		dlm_put_rsb(ri->rsb);
533 		kfree(ri);
534 	}
535 }
536 
537 static struct seq_operations format1_seq_ops = {
538 	.start = table_seq_start,
539 	.next  = table_seq_next,
540 	.stop  = table_seq_stop,
541 	.show  = table_seq_show,
542 };
543 
544 static struct seq_operations format2_seq_ops = {
545 	.start = table_seq_start,
546 	.next  = table_seq_next,
547 	.stop  = table_seq_stop,
548 	.show  = table_seq_show,
549 };
550 
551 static struct seq_operations format3_seq_ops = {
552 	.start = table_seq_start,
553 	.next  = table_seq_next,
554 	.stop  = table_seq_stop,
555 	.show  = table_seq_show,
556 };
557 
558 static const struct file_operations format1_fops;
559 static const struct file_operations format2_fops;
560 static const struct file_operations format3_fops;
561 
562 static int table_open(struct inode *inode, struct file *file)
563 {
564 	struct seq_file *seq;
565 	int ret = -1;
566 
567 	if (file->f_op == &format1_fops)
568 		ret = seq_open(file, &format1_seq_ops);
569 	else if (file->f_op == &format2_fops)
570 		ret = seq_open(file, &format2_seq_ops);
571 	else if (file->f_op == &format3_fops)
572 		ret = seq_open(file, &format3_seq_ops);
573 
574 	if (ret)
575 		return ret;
576 
577 	seq = file->private_data;
578 	seq->private = inode->i_private; /* the dlm_ls */
579 	return 0;
580 }
581 
582 static const struct file_operations format1_fops = {
583 	.owner   = THIS_MODULE,
584 	.open    = table_open,
585 	.read    = seq_read,
586 	.llseek  = seq_lseek,
587 	.release = seq_release
588 };
589 
590 static const struct file_operations format2_fops = {
591 	.owner   = THIS_MODULE,
592 	.open    = table_open,
593 	.read    = seq_read,
594 	.llseek  = seq_lseek,
595 	.release = seq_release
596 };
597 
598 static const struct file_operations format3_fops = {
599 	.owner   = THIS_MODULE,
600 	.open    = table_open,
601 	.read    = seq_read,
602 	.llseek  = seq_lseek,
603 	.release = seq_release
604 };
605 
606 /*
607  * dump lkb's on the ls_waiters list
608  */
609 
610 static int waiters_open(struct inode *inode, struct file *file)
611 {
612 	file->private_data = inode->i_private;
613 	return 0;
614 }
615 
616 static ssize_t waiters_read(struct file *file, char __user *userbuf,
617 			    size_t count, loff_t *ppos)
618 {
619 	struct dlm_ls *ls = file->private_data;
620 	struct dlm_lkb *lkb;
621 	size_t len = DLM_DEBUG_BUF_LEN, pos = 0, ret, rv;
622 
623 	mutex_lock(&debug_buf_lock);
624 	mutex_lock(&ls->ls_waiters_mutex);
625 	memset(debug_buf, 0, sizeof(debug_buf));
626 
627 	list_for_each_entry(lkb, &ls->ls_waiters, lkb_wait_reply) {
628 		ret = snprintf(debug_buf + pos, len - pos, "%x %d %d %s\n",
629 			       lkb->lkb_id, lkb->lkb_wait_type,
630 			       lkb->lkb_nodeid, lkb->lkb_resource->res_name);
631 		if (ret >= len - pos)
632 			break;
633 		pos += ret;
634 	}
635 	mutex_unlock(&ls->ls_waiters_mutex);
636 
637 	rv = simple_read_from_buffer(userbuf, count, ppos, debug_buf, pos);
638 	mutex_unlock(&debug_buf_lock);
639 	return rv;
640 }
641 
642 static const struct file_operations waiters_fops = {
643 	.owner   = THIS_MODULE,
644 	.open    = waiters_open,
645 	.read    = waiters_read
646 };
647 
648 void dlm_delete_debug_file(struct dlm_ls *ls)
649 {
650 	if (ls->ls_debug_rsb_dentry)
651 		debugfs_remove(ls->ls_debug_rsb_dentry);
652 	if (ls->ls_debug_waiters_dentry)
653 		debugfs_remove(ls->ls_debug_waiters_dentry);
654 	if (ls->ls_debug_locks_dentry)
655 		debugfs_remove(ls->ls_debug_locks_dentry);
656 	if (ls->ls_debug_all_dentry)
657 		debugfs_remove(ls->ls_debug_all_dentry);
658 }
659 
660 int dlm_create_debug_file(struct dlm_ls *ls)
661 {
662 	char name[DLM_LOCKSPACE_LEN+8];
663 
664 	/* format 1 */
665 
666 	ls->ls_debug_rsb_dentry = debugfs_create_file(ls->ls_name,
667 						      S_IFREG | S_IRUGO,
668 						      dlm_root,
669 						      ls,
670 						      &format1_fops);
671 	if (!ls->ls_debug_rsb_dentry)
672 		goto fail;
673 
674 	/* format 2 */
675 
676 	memset(name, 0, sizeof(name));
677 	snprintf(name, DLM_LOCKSPACE_LEN+8, "%s_locks", ls->ls_name);
678 
679 	ls->ls_debug_locks_dentry = debugfs_create_file(name,
680 							S_IFREG | S_IRUGO,
681 							dlm_root,
682 							ls,
683 							&format2_fops);
684 	if (!ls->ls_debug_locks_dentry)
685 		goto fail;
686 
687 	/* format 3 */
688 
689 	memset(name, 0, sizeof(name));
690 	snprintf(name, DLM_LOCKSPACE_LEN+8, "%s_all", ls->ls_name);
691 
692 	ls->ls_debug_all_dentry = debugfs_create_file(name,
693 						      S_IFREG | S_IRUGO,
694 						      dlm_root,
695 						      ls,
696 						      &format3_fops);
697 	if (!ls->ls_debug_all_dentry)
698 		goto fail;
699 
700 	memset(name, 0, sizeof(name));
701 	snprintf(name, DLM_LOCKSPACE_LEN+8, "%s_waiters", ls->ls_name);
702 
703 	ls->ls_debug_waiters_dentry = debugfs_create_file(name,
704 							  S_IFREG | S_IRUGO,
705 							  dlm_root,
706 							  ls,
707 							  &waiters_fops);
708 	if (!ls->ls_debug_waiters_dentry)
709 		goto fail;
710 
711 	return 0;
712 
713  fail:
714 	dlm_delete_debug_file(ls);
715 	return -ENOMEM;
716 }
717 
718 int __init dlm_register_debugfs(void)
719 {
720 	mutex_init(&debug_buf_lock);
721 	dlm_root = debugfs_create_dir("dlm", NULL);
722 	return dlm_root ? 0 : -ENOMEM;
723 }
724 
725 void dlm_unregister_debugfs(void)
726 {
727 	debugfs_remove(dlm_root);
728 }
729 
730