xref: /openbmc/linux/fs/dlm/debug_fs.c (revision 6c33a6f4)
1 // SPDX-License-Identifier: GPL-2.0-only
2 /******************************************************************************
3 *******************************************************************************
4 **
5 **  Copyright (C) 2005-2009 Red Hat, Inc.  All rights reserved.
6 **
7 **
8 *******************************************************************************
9 ******************************************************************************/
10 
11 #include <linux/pagemap.h>
12 #include <linux/seq_file.h>
13 #include <linux/init.h>
14 #include <linux/ctype.h>
15 #include <linux/debugfs.h>
16 #include <linux/slab.h>
17 
18 #include "dlm_internal.h"
19 #include "lock.h"
20 
21 #define DLM_DEBUG_BUF_LEN 4096
22 static char debug_buf[DLM_DEBUG_BUF_LEN];
23 static struct mutex debug_buf_lock;
24 
25 static struct dentry *dlm_root;
26 
27 static char *print_lockmode(int mode)
28 {
29 	switch (mode) {
30 	case DLM_LOCK_IV:
31 		return "--";
32 	case DLM_LOCK_NL:
33 		return "NL";
34 	case DLM_LOCK_CR:
35 		return "CR";
36 	case DLM_LOCK_CW:
37 		return "CW";
38 	case DLM_LOCK_PR:
39 		return "PR";
40 	case DLM_LOCK_PW:
41 		return "PW";
42 	case DLM_LOCK_EX:
43 		return "EX";
44 	default:
45 		return "??";
46 	}
47 }
48 
49 static void print_format1_lock(struct seq_file *s, struct dlm_lkb *lkb,
50 			       struct dlm_rsb *res)
51 {
52 	seq_printf(s, "%08x %s", lkb->lkb_id, print_lockmode(lkb->lkb_grmode));
53 
54 	if (lkb->lkb_status == DLM_LKSTS_CONVERT ||
55 	    lkb->lkb_status == DLM_LKSTS_WAITING)
56 		seq_printf(s, " (%s)", print_lockmode(lkb->lkb_rqmode));
57 
58 	if (lkb->lkb_nodeid) {
59 		if (lkb->lkb_nodeid != res->res_nodeid)
60 			seq_printf(s, " Remote: %3d %08x", lkb->lkb_nodeid,
61 				   lkb->lkb_remid);
62 		else
63 			seq_printf(s, " Master:     %08x", lkb->lkb_remid);
64 	}
65 
66 	if (lkb->lkb_wait_type)
67 		seq_printf(s, " wait_type: %d", lkb->lkb_wait_type);
68 
69 	seq_putc(s, '\n');
70 }
71 
72 static void print_format1(struct dlm_rsb *res, struct seq_file *s)
73 {
74 	struct dlm_lkb *lkb;
75 	int i, lvblen = res->res_ls->ls_lvblen, recover_list, root_list;
76 
77 	lock_rsb(res);
78 
79 	seq_printf(s, "\nResource %p Name (len=%d) \"", res, res->res_length);
80 
81 	for (i = 0; i < res->res_length; i++) {
82 		if (isprint(res->res_name[i]))
83 			seq_printf(s, "%c", res->res_name[i]);
84 		else
85 			seq_printf(s, "%c", '.');
86 	}
87 
88 	if (res->res_nodeid > 0)
89 		seq_printf(s, "\"\nLocal Copy, Master is node %d\n",
90 			   res->res_nodeid);
91 	else if (res->res_nodeid == 0)
92 		seq_puts(s, "\"\nMaster Copy\n");
93 	else if (res->res_nodeid == -1)
94 		seq_printf(s, "\"\nLooking up master (lkid %x)\n",
95 			   res->res_first_lkid);
96 	else
97 		seq_printf(s, "\"\nInvalid master %d\n", res->res_nodeid);
98 	if (seq_has_overflowed(s))
99 		goto out;
100 
101 	/* Print the LVB: */
102 	if (res->res_lvbptr) {
103 		seq_puts(s, "LVB: ");
104 		for (i = 0; i < lvblen; i++) {
105 			if (i == lvblen / 2)
106 				seq_puts(s, "\n     ");
107 			seq_printf(s, "%02x ",
108 				   (unsigned char) res->res_lvbptr[i]);
109 		}
110 		if (rsb_flag(res, RSB_VALNOTVALID))
111 			seq_puts(s, " (INVALID)");
112 		seq_putc(s, '\n');
113 		if (seq_has_overflowed(s))
114 			goto out;
115 	}
116 
117 	root_list = !list_empty(&res->res_root_list);
118 	recover_list = !list_empty(&res->res_recover_list);
119 
120 	if (root_list || recover_list) {
121 		seq_printf(s, "Recovery: root %d recover %d flags %lx count %d\n",
122 			   root_list, recover_list,
123 			   res->res_flags, res->res_recover_locks_count);
124 	}
125 
126 	/* Print the locks attached to this resource */
127 	seq_puts(s, "Granted Queue\n");
128 	list_for_each_entry(lkb, &res->res_grantqueue, lkb_statequeue) {
129 		print_format1_lock(s, lkb, res);
130 		if (seq_has_overflowed(s))
131 			goto out;
132 	}
133 
134 	seq_puts(s, "Conversion Queue\n");
135 	list_for_each_entry(lkb, &res->res_convertqueue, lkb_statequeue) {
136 		print_format1_lock(s, lkb, res);
137 		if (seq_has_overflowed(s))
138 			goto out;
139 	}
140 
141 	seq_puts(s, "Waiting Queue\n");
142 	list_for_each_entry(lkb, &res->res_waitqueue, lkb_statequeue) {
143 		print_format1_lock(s, lkb, res);
144 		if (seq_has_overflowed(s))
145 			goto out;
146 	}
147 
148 	if (list_empty(&res->res_lookup))
149 		goto out;
150 
151 	seq_puts(s, "Lookup Queue\n");
152 	list_for_each_entry(lkb, &res->res_lookup, lkb_rsb_lookup) {
153 		seq_printf(s, "%08x %s",
154 			   lkb->lkb_id, print_lockmode(lkb->lkb_rqmode));
155 		if (lkb->lkb_wait_type)
156 			seq_printf(s, " wait_type: %d", lkb->lkb_wait_type);
157 		seq_putc(s, '\n');
158 		if (seq_has_overflowed(s))
159 			goto out;
160 	}
161  out:
162 	unlock_rsb(res);
163 }
164 
165 static void print_format2_lock(struct seq_file *s, struct dlm_lkb *lkb,
166 			       struct dlm_rsb *r)
167 {
168 	u64 xid = 0;
169 	u64 us;
170 
171 	if (lkb->lkb_flags & DLM_IFL_USER) {
172 		if (lkb->lkb_ua)
173 			xid = lkb->lkb_ua->xid;
174 	}
175 
176 	/* microseconds since lkb was added to current queue */
177 	us = ktime_to_us(ktime_sub(ktime_get(), lkb->lkb_timestamp));
178 
179 	/* id nodeid remid pid xid exflags flags sts grmode rqmode time_us
180 	   r_nodeid r_len r_name */
181 
182 	seq_printf(s, "%x %d %x %u %llu %x %x %d %d %d %llu %u %d \"%s\"\n",
183 		   lkb->lkb_id,
184 		   lkb->lkb_nodeid,
185 		   lkb->lkb_remid,
186 		   lkb->lkb_ownpid,
187 		   (unsigned long long)xid,
188 		   lkb->lkb_exflags,
189 		   lkb->lkb_flags,
190 		   lkb->lkb_status,
191 		   lkb->lkb_grmode,
192 		   lkb->lkb_rqmode,
193 		   (unsigned long long)us,
194 		   r->res_nodeid,
195 		   r->res_length,
196 		   r->res_name);
197 }
198 
199 static void print_format2(struct dlm_rsb *r, struct seq_file *s)
200 {
201 	struct dlm_lkb *lkb;
202 
203 	lock_rsb(r);
204 
205 	list_for_each_entry(lkb, &r->res_grantqueue, lkb_statequeue) {
206 		print_format2_lock(s, lkb, r);
207 		if (seq_has_overflowed(s))
208 			goto out;
209 	}
210 
211 	list_for_each_entry(lkb, &r->res_convertqueue, lkb_statequeue) {
212 		print_format2_lock(s, lkb, r);
213 		if (seq_has_overflowed(s))
214 			goto out;
215 	}
216 
217 	list_for_each_entry(lkb, &r->res_waitqueue, lkb_statequeue) {
218 		print_format2_lock(s, lkb, r);
219 		if (seq_has_overflowed(s))
220 			goto out;
221 	}
222  out:
223 	unlock_rsb(r);
224 }
225 
226 static void print_format3_lock(struct seq_file *s, struct dlm_lkb *lkb,
227 			      int rsb_lookup)
228 {
229 	u64 xid = 0;
230 
231 	if (lkb->lkb_flags & DLM_IFL_USER) {
232 		if (lkb->lkb_ua)
233 			xid = lkb->lkb_ua->xid;
234 	}
235 
236 	seq_printf(s, "lkb %x %d %x %u %llu %x %x %d %d %d %d %d %d %u %llu %llu\n",
237 		   lkb->lkb_id,
238 		   lkb->lkb_nodeid,
239 		   lkb->lkb_remid,
240 		   lkb->lkb_ownpid,
241 		   (unsigned long long)xid,
242 		   lkb->lkb_exflags,
243 		   lkb->lkb_flags,
244 		   lkb->lkb_status,
245 		   lkb->lkb_grmode,
246 		   lkb->lkb_rqmode,
247 		   lkb->lkb_last_bast.mode,
248 		   rsb_lookup,
249 		   lkb->lkb_wait_type,
250 		   lkb->lkb_lvbseq,
251 		   (unsigned long long)ktime_to_ns(lkb->lkb_timestamp),
252 		   (unsigned long long)ktime_to_ns(lkb->lkb_last_bast_time));
253 }
254 
255 static void print_format3(struct dlm_rsb *r, struct seq_file *s)
256 {
257 	struct dlm_lkb *lkb;
258 	int i, lvblen = r->res_ls->ls_lvblen;
259 	int print_name = 1;
260 
261 	lock_rsb(r);
262 
263 	seq_printf(s, "rsb %p %d %x %lx %d %d %u %d ",
264 		   r,
265 		   r->res_nodeid,
266 		   r->res_first_lkid,
267 		   r->res_flags,
268 		   !list_empty(&r->res_root_list),
269 		   !list_empty(&r->res_recover_list),
270 		   r->res_recover_locks_count,
271 		   r->res_length);
272 	if (seq_has_overflowed(s))
273 		goto out;
274 
275 	for (i = 0; i < r->res_length; i++) {
276 		if (!isascii(r->res_name[i]) || !isprint(r->res_name[i]))
277 			print_name = 0;
278 	}
279 
280 	seq_puts(s, print_name ? "str " : "hex");
281 
282 	for (i = 0; i < r->res_length; i++) {
283 		if (print_name)
284 			seq_printf(s, "%c", r->res_name[i]);
285 		else
286 			seq_printf(s, " %02x", (unsigned char)r->res_name[i]);
287 	}
288 	seq_putc(s, '\n');
289 	if (seq_has_overflowed(s))
290 		goto out;
291 
292 	if (!r->res_lvbptr)
293 		goto do_locks;
294 
295 	seq_printf(s, "lvb %u %d", r->res_lvbseq, lvblen);
296 
297 	for (i = 0; i < lvblen; i++)
298 		seq_printf(s, " %02x", (unsigned char)r->res_lvbptr[i]);
299 	seq_putc(s, '\n');
300 	if (seq_has_overflowed(s))
301 		goto out;
302 
303  do_locks:
304 	list_for_each_entry(lkb, &r->res_grantqueue, lkb_statequeue) {
305 		print_format3_lock(s, lkb, 0);
306 		if (seq_has_overflowed(s))
307 			goto out;
308 	}
309 
310 	list_for_each_entry(lkb, &r->res_convertqueue, lkb_statequeue) {
311 		print_format3_lock(s, lkb, 0);
312 		if (seq_has_overflowed(s))
313 			goto out;
314 	}
315 
316 	list_for_each_entry(lkb, &r->res_waitqueue, lkb_statequeue) {
317 		print_format3_lock(s, lkb, 0);
318 		if (seq_has_overflowed(s))
319 			goto out;
320 	}
321 
322 	list_for_each_entry(lkb, &r->res_lookup, lkb_rsb_lookup) {
323 		print_format3_lock(s, lkb, 1);
324 		if (seq_has_overflowed(s))
325 			goto out;
326 	}
327  out:
328 	unlock_rsb(r);
329 }
330 
331 static void print_format4(struct dlm_rsb *r, struct seq_file *s)
332 {
333 	int our_nodeid = dlm_our_nodeid();
334 	int print_name = 1;
335 	int i;
336 
337 	lock_rsb(r);
338 
339 	seq_printf(s, "rsb %p %d %d %d %d %lu %lx %d ",
340 		   r,
341 		   r->res_nodeid,
342 		   r->res_master_nodeid,
343 		   r->res_dir_nodeid,
344 		   our_nodeid,
345 		   r->res_toss_time,
346 		   r->res_flags,
347 		   r->res_length);
348 
349 	for (i = 0; i < r->res_length; i++) {
350 		if (!isascii(r->res_name[i]) || !isprint(r->res_name[i]))
351 			print_name = 0;
352 	}
353 
354 	seq_puts(s, print_name ? "str " : "hex");
355 
356 	for (i = 0; i < r->res_length; i++) {
357 		if (print_name)
358 			seq_printf(s, "%c", r->res_name[i]);
359 		else
360 			seq_printf(s, " %02x", (unsigned char)r->res_name[i]);
361 	}
362 	seq_putc(s, '\n');
363 	unlock_rsb(r);
364 }
365 
366 struct rsbtbl_iter {
367 	struct dlm_rsb *rsb;
368 	unsigned bucket;
369 	int format;
370 	int header;
371 };
372 
373 /*
374  * If the buffer is full, seq_printf can be called again, but it
375  * does nothing.  So, the these printing routines periodically check
376  * seq_has_overflowed to avoid wasting too much time trying to print to
377  * a full buffer.
378  */
379 
380 static int table_seq_show(struct seq_file *seq, void *iter_ptr)
381 {
382 	struct rsbtbl_iter *ri = iter_ptr;
383 
384 	switch (ri->format) {
385 	case 1:
386 		print_format1(ri->rsb, seq);
387 		break;
388 	case 2:
389 		if (ri->header) {
390 			seq_puts(seq, "id nodeid remid pid xid exflags flags sts grmode rqmode time_ms r_nodeid r_len r_name\n");
391 			ri->header = 0;
392 		}
393 		print_format2(ri->rsb, seq);
394 		break;
395 	case 3:
396 		if (ri->header) {
397 			seq_puts(seq, "version rsb 1.1 lvb 1.1 lkb 1.1\n");
398 			ri->header = 0;
399 		}
400 		print_format3(ri->rsb, seq);
401 		break;
402 	case 4:
403 		if (ri->header) {
404 			seq_puts(seq, "version 4 rsb 2\n");
405 			ri->header = 0;
406 		}
407 		print_format4(ri->rsb, seq);
408 		break;
409 	}
410 
411 	return 0;
412 }
413 
414 static const struct seq_operations format1_seq_ops;
415 static const struct seq_operations format2_seq_ops;
416 static const struct seq_operations format3_seq_ops;
417 static const struct seq_operations format4_seq_ops;
418 
419 static void *table_seq_start(struct seq_file *seq, loff_t *pos)
420 {
421 	struct rb_root *tree;
422 	struct rb_node *node;
423 	struct dlm_ls *ls = seq->private;
424 	struct rsbtbl_iter *ri;
425 	struct dlm_rsb *r;
426 	loff_t n = *pos;
427 	unsigned bucket, entry;
428 	int toss = (seq->op == &format4_seq_ops);
429 
430 	bucket = n >> 32;
431 	entry = n & ((1LL << 32) - 1);
432 
433 	if (bucket >= ls->ls_rsbtbl_size)
434 		return NULL;
435 
436 	ri = kzalloc(sizeof(*ri), GFP_NOFS);
437 	if (!ri)
438 		return NULL;
439 	if (n == 0)
440 		ri->header = 1;
441 	if (seq->op == &format1_seq_ops)
442 		ri->format = 1;
443 	if (seq->op == &format2_seq_ops)
444 		ri->format = 2;
445 	if (seq->op == &format3_seq_ops)
446 		ri->format = 3;
447 	if (seq->op == &format4_seq_ops)
448 		ri->format = 4;
449 
450 	tree = toss ? &ls->ls_rsbtbl[bucket].toss : &ls->ls_rsbtbl[bucket].keep;
451 
452 	spin_lock(&ls->ls_rsbtbl[bucket].lock);
453 	if (!RB_EMPTY_ROOT(tree)) {
454 		for (node = rb_first(tree); node; node = rb_next(node)) {
455 			r = rb_entry(node, struct dlm_rsb, res_hashnode);
456 			if (!entry--) {
457 				dlm_hold_rsb(r);
458 				ri->rsb = r;
459 				ri->bucket = bucket;
460 				spin_unlock(&ls->ls_rsbtbl[bucket].lock);
461 				return ri;
462 			}
463 		}
464 	}
465 	spin_unlock(&ls->ls_rsbtbl[bucket].lock);
466 
467 	/*
468 	 * move to the first rsb in the next non-empty bucket
469 	 */
470 
471 	/* zero the entry */
472 	n &= ~((1LL << 32) - 1);
473 
474 	while (1) {
475 		bucket++;
476 		n += 1LL << 32;
477 
478 		if (bucket >= ls->ls_rsbtbl_size) {
479 			kfree(ri);
480 			return NULL;
481 		}
482 		tree = toss ? &ls->ls_rsbtbl[bucket].toss : &ls->ls_rsbtbl[bucket].keep;
483 
484 		spin_lock(&ls->ls_rsbtbl[bucket].lock);
485 		if (!RB_EMPTY_ROOT(tree)) {
486 			node = rb_first(tree);
487 			r = rb_entry(node, struct dlm_rsb, res_hashnode);
488 			dlm_hold_rsb(r);
489 			ri->rsb = r;
490 			ri->bucket = bucket;
491 			spin_unlock(&ls->ls_rsbtbl[bucket].lock);
492 			*pos = n;
493 			return ri;
494 		}
495 		spin_unlock(&ls->ls_rsbtbl[bucket].lock);
496 	}
497 }
498 
499 static void *table_seq_next(struct seq_file *seq, void *iter_ptr, loff_t *pos)
500 {
501 	struct dlm_ls *ls = seq->private;
502 	struct rsbtbl_iter *ri = iter_ptr;
503 	struct rb_root *tree;
504 	struct rb_node *next;
505 	struct dlm_rsb *r, *rp;
506 	loff_t n = *pos;
507 	unsigned bucket;
508 	int toss = (seq->op == &format4_seq_ops);
509 
510 	bucket = n >> 32;
511 
512 	/*
513 	 * move to the next rsb in the same bucket
514 	 */
515 
516 	spin_lock(&ls->ls_rsbtbl[bucket].lock);
517 	rp = ri->rsb;
518 	next = rb_next(&rp->res_hashnode);
519 
520 	if (next) {
521 		r = rb_entry(next, struct dlm_rsb, res_hashnode);
522 		dlm_hold_rsb(r);
523 		ri->rsb = r;
524 		spin_unlock(&ls->ls_rsbtbl[bucket].lock);
525 		dlm_put_rsb(rp);
526 		++*pos;
527 		return ri;
528 	}
529 	spin_unlock(&ls->ls_rsbtbl[bucket].lock);
530 	dlm_put_rsb(rp);
531 
532 	/*
533 	 * move to the first rsb in the next non-empty bucket
534 	 */
535 
536 	/* zero the entry */
537 	n &= ~((1LL << 32) - 1);
538 
539 	while (1) {
540 		bucket++;
541 		n += 1LL << 32;
542 
543 		if (bucket >= ls->ls_rsbtbl_size) {
544 			kfree(ri);
545 			return NULL;
546 		}
547 		tree = toss ? &ls->ls_rsbtbl[bucket].toss : &ls->ls_rsbtbl[bucket].keep;
548 
549 		spin_lock(&ls->ls_rsbtbl[bucket].lock);
550 		if (!RB_EMPTY_ROOT(tree)) {
551 			next = rb_first(tree);
552 			r = rb_entry(next, struct dlm_rsb, res_hashnode);
553 			dlm_hold_rsb(r);
554 			ri->rsb = r;
555 			ri->bucket = bucket;
556 			spin_unlock(&ls->ls_rsbtbl[bucket].lock);
557 			*pos = n;
558 			return ri;
559 		}
560 		spin_unlock(&ls->ls_rsbtbl[bucket].lock);
561 	}
562 }
563 
564 static void table_seq_stop(struct seq_file *seq, void *iter_ptr)
565 {
566 	struct rsbtbl_iter *ri = iter_ptr;
567 
568 	if (ri) {
569 		dlm_put_rsb(ri->rsb);
570 		kfree(ri);
571 	}
572 }
573 
574 static const struct seq_operations format1_seq_ops = {
575 	.start = table_seq_start,
576 	.next  = table_seq_next,
577 	.stop  = table_seq_stop,
578 	.show  = table_seq_show,
579 };
580 
581 static const struct seq_operations format2_seq_ops = {
582 	.start = table_seq_start,
583 	.next  = table_seq_next,
584 	.stop  = table_seq_stop,
585 	.show  = table_seq_show,
586 };
587 
588 static const struct seq_operations format3_seq_ops = {
589 	.start = table_seq_start,
590 	.next  = table_seq_next,
591 	.stop  = table_seq_stop,
592 	.show  = table_seq_show,
593 };
594 
595 static const struct seq_operations format4_seq_ops = {
596 	.start = table_seq_start,
597 	.next  = table_seq_next,
598 	.stop  = table_seq_stop,
599 	.show  = table_seq_show,
600 };
601 
602 static const struct file_operations format1_fops;
603 static const struct file_operations format2_fops;
604 static const struct file_operations format3_fops;
605 static const struct file_operations format4_fops;
606 
607 static int table_open1(struct inode *inode, struct file *file)
608 {
609 	struct seq_file *seq;
610 	int ret;
611 
612 	ret = seq_open(file, &format1_seq_ops);
613 	if (ret)
614 		return ret;
615 
616 	seq = file->private_data;
617 	seq->private = inode->i_private; /* the dlm_ls */
618 	return 0;
619 }
620 
621 static int table_open2(struct inode *inode, struct file *file)
622 {
623 	struct seq_file *seq;
624 	int ret;
625 
626 	ret = seq_open(file, &format2_seq_ops);
627 	if (ret)
628 		return ret;
629 
630 	seq = file->private_data;
631 	seq->private = inode->i_private; /* the dlm_ls */
632 	return 0;
633 }
634 
635 static int table_open3(struct inode *inode, struct file *file)
636 {
637 	struct seq_file *seq;
638 	int ret;
639 
640 	ret = seq_open(file, &format3_seq_ops);
641 	if (ret)
642 		return ret;
643 
644 	seq = file->private_data;
645 	seq->private = inode->i_private; /* the dlm_ls */
646 	return 0;
647 }
648 
649 static int table_open4(struct inode *inode, struct file *file)
650 {
651 	struct seq_file *seq;
652 	int ret;
653 
654 	ret = seq_open(file, &format4_seq_ops);
655 	if (ret)
656 		return ret;
657 
658 	seq = file->private_data;
659 	seq->private = inode->i_private; /* the dlm_ls */
660 	return 0;
661 }
662 
663 static const struct file_operations format1_fops = {
664 	.owner   = THIS_MODULE,
665 	.open    = table_open1,
666 	.read    = seq_read,
667 	.llseek  = seq_lseek,
668 	.release = seq_release
669 };
670 
671 static const struct file_operations format2_fops = {
672 	.owner   = THIS_MODULE,
673 	.open    = table_open2,
674 	.read    = seq_read,
675 	.llseek  = seq_lseek,
676 	.release = seq_release
677 };
678 
679 static const struct file_operations format3_fops = {
680 	.owner   = THIS_MODULE,
681 	.open    = table_open3,
682 	.read    = seq_read,
683 	.llseek  = seq_lseek,
684 	.release = seq_release
685 };
686 
687 static const struct file_operations format4_fops = {
688 	.owner   = THIS_MODULE,
689 	.open    = table_open4,
690 	.read    = seq_read,
691 	.llseek  = seq_lseek,
692 	.release = seq_release
693 };
694 
695 /*
696  * dump lkb's on the ls_waiters list
697  */
698 static ssize_t waiters_read(struct file *file, char __user *userbuf,
699 			    size_t count, loff_t *ppos)
700 {
701 	struct dlm_ls *ls = file->private_data;
702 	struct dlm_lkb *lkb;
703 	size_t len = DLM_DEBUG_BUF_LEN, pos = 0, ret, rv;
704 
705 	mutex_lock(&debug_buf_lock);
706 	mutex_lock(&ls->ls_waiters_mutex);
707 	memset(debug_buf, 0, sizeof(debug_buf));
708 
709 	list_for_each_entry(lkb, &ls->ls_waiters, lkb_wait_reply) {
710 		ret = snprintf(debug_buf + pos, len - pos, "%x %d %d %s\n",
711 			       lkb->lkb_id, lkb->lkb_wait_type,
712 			       lkb->lkb_nodeid, lkb->lkb_resource->res_name);
713 		if (ret >= len - pos)
714 			break;
715 		pos += ret;
716 	}
717 	mutex_unlock(&ls->ls_waiters_mutex);
718 
719 	rv = simple_read_from_buffer(userbuf, count, ppos, debug_buf, pos);
720 	mutex_unlock(&debug_buf_lock);
721 	return rv;
722 }
723 
724 static const struct file_operations waiters_fops = {
725 	.owner   = THIS_MODULE,
726 	.open    = simple_open,
727 	.read    = waiters_read,
728 	.llseek  = default_llseek,
729 };
730 
731 void dlm_delete_debug_file(struct dlm_ls *ls)
732 {
733 	debugfs_remove(ls->ls_debug_rsb_dentry);
734 	debugfs_remove(ls->ls_debug_waiters_dentry);
735 	debugfs_remove(ls->ls_debug_locks_dentry);
736 	debugfs_remove(ls->ls_debug_all_dentry);
737 	debugfs_remove(ls->ls_debug_toss_dentry);
738 }
739 
740 void dlm_create_debug_file(struct dlm_ls *ls)
741 {
742 	char name[DLM_LOCKSPACE_LEN + 8];
743 
744 	/* format 1 */
745 
746 	ls->ls_debug_rsb_dentry = debugfs_create_file(ls->ls_name,
747 						      S_IFREG | S_IRUGO,
748 						      dlm_root,
749 						      ls,
750 						      &format1_fops);
751 
752 	/* format 2 */
753 
754 	memset(name, 0, sizeof(name));
755 	snprintf(name, DLM_LOCKSPACE_LEN + 8, "%s_locks", ls->ls_name);
756 
757 	ls->ls_debug_locks_dentry = debugfs_create_file(name,
758 							S_IFREG | S_IRUGO,
759 							dlm_root,
760 							ls,
761 							&format2_fops);
762 
763 	/* format 3 */
764 
765 	memset(name, 0, sizeof(name));
766 	snprintf(name, DLM_LOCKSPACE_LEN + 8, "%s_all", ls->ls_name);
767 
768 	ls->ls_debug_all_dentry = debugfs_create_file(name,
769 						      S_IFREG | S_IRUGO,
770 						      dlm_root,
771 						      ls,
772 						      &format3_fops);
773 
774 	/* format 4 */
775 
776 	memset(name, 0, sizeof(name));
777 	snprintf(name, DLM_LOCKSPACE_LEN + 8, "%s_toss", ls->ls_name);
778 
779 	ls->ls_debug_toss_dentry = debugfs_create_file(name,
780 						       S_IFREG | S_IRUGO,
781 						       dlm_root,
782 						       ls,
783 						       &format4_fops);
784 
785 	memset(name, 0, sizeof(name));
786 	snprintf(name, DLM_LOCKSPACE_LEN + 8, "%s_waiters", ls->ls_name);
787 
788 	ls->ls_debug_waiters_dentry = debugfs_create_file(name,
789 							  S_IFREG | S_IRUGO,
790 							  dlm_root,
791 							  ls,
792 							  &waiters_fops);
793 }
794 
795 void __init dlm_register_debugfs(void)
796 {
797 	mutex_init(&debug_buf_lock);
798 	dlm_root = debugfs_create_dir("dlm", NULL);
799 }
800 
801 void dlm_unregister_debugfs(void)
802 {
803 	debugfs_remove(dlm_root);
804 }
805 
806