xref: /openbmc/linux/fs/dlm/debug_fs.c (revision 9b93eb47)
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/init.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 void 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 	seq_putc(s, '\n');
72 }
73 
74 static void 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 
79 	lock_rsb(res);
80 
81 	seq_printf(s, "\nResource %p Name (len=%d) \"", res, res->res_length);
82 
83 	for (i = 0; i < res->res_length; i++) {
84 		if (isprint(res->res_name[i]))
85 			seq_printf(s, "%c", res->res_name[i]);
86 		else
87 			seq_printf(s, "%c", '.');
88 	}
89 
90 	if (res->res_nodeid > 0)
91 		seq_printf(s, "\"\nLocal Copy, Master is node %d\n",
92 			   res->res_nodeid);
93 	else if (res->res_nodeid == 0)
94 		seq_puts(s, "\"\nMaster Copy\n");
95 	else if (res->res_nodeid == -1)
96 		seq_printf(s, "\"\nLooking up master (lkid %x)\n",
97 			   res->res_first_lkid);
98 	else
99 		seq_printf(s, "\"\nInvalid master %d\n", res->res_nodeid);
100 	if (seq_has_overflowed(s))
101 		goto out;
102 
103 	/* Print the LVB: */
104 	if (res->res_lvbptr) {
105 		seq_puts(s, "LVB: ");
106 		for (i = 0; i < lvblen; i++) {
107 			if (i == lvblen / 2)
108 				seq_puts(s, "\n     ");
109 			seq_printf(s, "%02x ",
110 				   (unsigned char) res->res_lvbptr[i]);
111 		}
112 		if (rsb_flag(res, RSB_VALNOTVALID))
113 			seq_puts(s, " (INVALID)");
114 		seq_putc(s, '\n');
115 		if (seq_has_overflowed(s))
116 			goto out;
117 	}
118 
119 	root_list = !list_empty(&res->res_root_list);
120 	recover_list = !list_empty(&res->res_recover_list);
121 
122 	if (root_list || recover_list) {
123 		seq_printf(s, "Recovery: root %d recover %d flags %lx count %d\n",
124 			   root_list, recover_list,
125 			   res->res_flags, res->res_recover_locks_count);
126 	}
127 
128 	/* Print the locks attached to this resource */
129 	seq_puts(s, "Granted Queue\n");
130 	list_for_each_entry(lkb, &res->res_grantqueue, lkb_statequeue) {
131 		print_format1_lock(s, lkb, res);
132 		if (seq_has_overflowed(s))
133 			goto out;
134 	}
135 
136 	seq_puts(s, "Conversion Queue\n");
137 	list_for_each_entry(lkb, &res->res_convertqueue, lkb_statequeue) {
138 		print_format1_lock(s, lkb, res);
139 		if (seq_has_overflowed(s))
140 			goto out;
141 	}
142 
143 	seq_puts(s, "Waiting Queue\n");
144 	list_for_each_entry(lkb, &res->res_waitqueue, lkb_statequeue) {
145 		print_format1_lock(s, lkb, res);
146 		if (seq_has_overflowed(s))
147 			goto out;
148 	}
149 
150 	if (list_empty(&res->res_lookup))
151 		goto out;
152 
153 	seq_puts(s, "Lookup Queue\n");
154 	list_for_each_entry(lkb, &res->res_lookup, lkb_rsb_lookup) {
155 		seq_printf(s, "%08x %s",
156 			   lkb->lkb_id, print_lockmode(lkb->lkb_rqmode));
157 		if (lkb->lkb_wait_type)
158 			seq_printf(s, " wait_type: %d", lkb->lkb_wait_type);
159 		seq_putc(s, '\n');
160 		if (seq_has_overflowed(s))
161 			goto out;
162 	}
163  out:
164 	unlock_rsb(res);
165 }
166 
167 static void print_format2_lock(struct seq_file *s, struct dlm_lkb *lkb,
168 			       struct dlm_rsb *r)
169 {
170 	u64 xid = 0;
171 	u64 us;
172 
173 	if (lkb->lkb_flags & DLM_IFL_USER) {
174 		if (lkb->lkb_ua)
175 			xid = lkb->lkb_ua->xid;
176 	}
177 
178 	/* microseconds since lkb was added to current queue */
179 	us = ktime_to_us(ktime_sub(ktime_get(), lkb->lkb_timestamp));
180 
181 	/* id nodeid remid pid xid exflags flags sts grmode rqmode time_us
182 	   r_nodeid r_len r_name */
183 
184 	seq_printf(s, "%x %d %x %u %llu %x %x %d %d %d %llu %u %d \"%s\"\n",
185 		   lkb->lkb_id,
186 		   lkb->lkb_nodeid,
187 		   lkb->lkb_remid,
188 		   lkb->lkb_ownpid,
189 		   (unsigned long long)xid,
190 		   lkb->lkb_exflags,
191 		   lkb->lkb_flags,
192 		   lkb->lkb_status,
193 		   lkb->lkb_grmode,
194 		   lkb->lkb_rqmode,
195 		   (unsigned long long)us,
196 		   r->res_nodeid,
197 		   r->res_length,
198 		   r->res_name);
199 }
200 
201 static void print_format2(struct dlm_rsb *r, struct seq_file *s)
202 {
203 	struct dlm_lkb *lkb;
204 
205 	lock_rsb(r);
206 
207 	list_for_each_entry(lkb, &r->res_grantqueue, lkb_statequeue) {
208 		print_format2_lock(s, lkb, r);
209 		if (seq_has_overflowed(s))
210 			goto out;
211 	}
212 
213 	list_for_each_entry(lkb, &r->res_convertqueue, lkb_statequeue) {
214 		print_format2_lock(s, lkb, r);
215 		if (seq_has_overflowed(s))
216 			goto out;
217 	}
218 
219 	list_for_each_entry(lkb, &r->res_waitqueue, lkb_statequeue) {
220 		print_format2_lock(s, lkb, r);
221 		if (seq_has_overflowed(s))
222 			goto out;
223 	}
224  out:
225 	unlock_rsb(r);
226 }
227 
228 static void print_format3_lock(struct seq_file *s, struct dlm_lkb *lkb,
229 			      int rsb_lookup)
230 {
231 	u64 xid = 0;
232 
233 	if (lkb->lkb_flags & DLM_IFL_USER) {
234 		if (lkb->lkb_ua)
235 			xid = lkb->lkb_ua->xid;
236 	}
237 
238 	seq_printf(s, "lkb %x %d %x %u %llu %x %x %d %d %d %d %d %d %u %llu %llu\n",
239 		   lkb->lkb_id,
240 		   lkb->lkb_nodeid,
241 		   lkb->lkb_remid,
242 		   lkb->lkb_ownpid,
243 		   (unsigned long long)xid,
244 		   lkb->lkb_exflags,
245 		   lkb->lkb_flags,
246 		   lkb->lkb_status,
247 		   lkb->lkb_grmode,
248 		   lkb->lkb_rqmode,
249 		   lkb->lkb_last_bast.mode,
250 		   rsb_lookup,
251 		   lkb->lkb_wait_type,
252 		   lkb->lkb_lvbseq,
253 		   (unsigned long long)ktime_to_ns(lkb->lkb_timestamp),
254 		   (unsigned long long)ktime_to_ns(lkb->lkb_last_bast_time));
255 }
256 
257 static void print_format3(struct dlm_rsb *r, struct seq_file *s)
258 {
259 	struct dlm_lkb *lkb;
260 	int i, lvblen = r->res_ls->ls_lvblen;
261 	int print_name = 1;
262 
263 	lock_rsb(r);
264 
265 	seq_printf(s, "rsb %p %d %x %lx %d %d %u %d ",
266 		   r,
267 		   r->res_nodeid,
268 		   r->res_first_lkid,
269 		   r->res_flags,
270 		   !list_empty(&r->res_root_list),
271 		   !list_empty(&r->res_recover_list),
272 		   r->res_recover_locks_count,
273 		   r->res_length);
274 	if (seq_has_overflowed(s))
275 		goto out;
276 
277 	for (i = 0; i < r->res_length; i++) {
278 		if (!isascii(r->res_name[i]) || !isprint(r->res_name[i]))
279 			print_name = 0;
280 	}
281 
282 	seq_puts(s, print_name ? "str " : "hex");
283 
284 	for (i = 0; i < r->res_length; i++) {
285 		if (print_name)
286 			seq_printf(s, "%c", r->res_name[i]);
287 		else
288 			seq_printf(s, " %02x", (unsigned char)r->res_name[i]);
289 	}
290 	seq_putc(s, '\n');
291 	if (seq_has_overflowed(s))
292 		goto out;
293 
294 	if (!r->res_lvbptr)
295 		goto do_locks;
296 
297 	seq_printf(s, "lvb %u %d", r->res_lvbseq, lvblen);
298 
299 	for (i = 0; i < lvblen; i++)
300 		seq_printf(s, " %02x", (unsigned char)r->res_lvbptr[i]);
301 	seq_putc(s, '\n');
302 	if (seq_has_overflowed(s))
303 		goto out;
304 
305  do_locks:
306 	list_for_each_entry(lkb, &r->res_grantqueue, lkb_statequeue) {
307 		print_format3_lock(s, lkb, 0);
308 		if (seq_has_overflowed(s))
309 			goto out;
310 	}
311 
312 	list_for_each_entry(lkb, &r->res_convertqueue, lkb_statequeue) {
313 		print_format3_lock(s, lkb, 0);
314 		if (seq_has_overflowed(s))
315 			goto out;
316 	}
317 
318 	list_for_each_entry(lkb, &r->res_waitqueue, lkb_statequeue) {
319 		print_format3_lock(s, lkb, 0);
320 		if (seq_has_overflowed(s))
321 			goto out;
322 	}
323 
324 	list_for_each_entry(lkb, &r->res_lookup, lkb_rsb_lookup) {
325 		print_format3_lock(s, lkb, 1);
326 		if (seq_has_overflowed(s))
327 			goto out;
328 	}
329  out:
330 	unlock_rsb(r);
331 }
332 
333 static void print_format4(struct dlm_rsb *r, struct seq_file *s)
334 {
335 	int our_nodeid = dlm_our_nodeid();
336 	int print_name = 1;
337 	int i;
338 
339 	lock_rsb(r);
340 
341 	seq_printf(s, "rsb %p %d %d %d %d %lu %lx %d ",
342 		   r,
343 		   r->res_nodeid,
344 		   r->res_master_nodeid,
345 		   r->res_dir_nodeid,
346 		   our_nodeid,
347 		   r->res_toss_time,
348 		   r->res_flags,
349 		   r->res_length);
350 
351 	for (i = 0; i < r->res_length; i++) {
352 		if (!isascii(r->res_name[i]) || !isprint(r->res_name[i]))
353 			print_name = 0;
354 	}
355 
356 	seq_puts(s, print_name ? "str " : "hex");
357 
358 	for (i = 0; i < r->res_length; i++) {
359 		if (print_name)
360 			seq_printf(s, "%c", r->res_name[i]);
361 		else
362 			seq_printf(s, " %02x", (unsigned char)r->res_name[i]);
363 	}
364 	seq_putc(s, '\n');
365 	unlock_rsb(r);
366 }
367 
368 struct rsbtbl_iter {
369 	struct dlm_rsb *rsb;
370 	unsigned bucket;
371 	int format;
372 	int header;
373 };
374 
375 /*
376  * If the buffer is full, seq_printf can be called again, but it
377  * does nothing.  So, the these printing routines periodically check
378  * seq_has_overflowed to avoid wasting too much time trying to print to
379  * a full buffer.
380  */
381 
382 static int table_seq_show(struct seq_file *seq, void *iter_ptr)
383 {
384 	struct rsbtbl_iter *ri = iter_ptr;
385 
386 	switch (ri->format) {
387 	case 1:
388 		print_format1(ri->rsb, seq);
389 		break;
390 	case 2:
391 		if (ri->header) {
392 			seq_puts(seq, "id nodeid remid pid xid exflags flags sts grmode rqmode time_ms r_nodeid r_len r_name\n");
393 			ri->header = 0;
394 		}
395 		print_format2(ri->rsb, seq);
396 		break;
397 	case 3:
398 		if (ri->header) {
399 			seq_puts(seq, "version rsb 1.1 lvb 1.1 lkb 1.1\n");
400 			ri->header = 0;
401 		}
402 		print_format3(ri->rsb, seq);
403 		break;
404 	case 4:
405 		if (ri->header) {
406 			seq_puts(seq, "version 4 rsb 2\n");
407 			ri->header = 0;
408 		}
409 		print_format4(ri->rsb, seq);
410 		break;
411 	}
412 
413 	return 0;
414 }
415 
416 static const struct seq_operations format1_seq_ops;
417 static const struct seq_operations format2_seq_ops;
418 static const struct seq_operations format3_seq_ops;
419 static const struct seq_operations format4_seq_ops;
420 
421 static void *table_seq_start(struct seq_file *seq, loff_t *pos)
422 {
423 	struct rb_root *tree;
424 	struct rb_node *node;
425 	struct dlm_ls *ls = seq->private;
426 	struct rsbtbl_iter *ri;
427 	struct dlm_rsb *r;
428 	loff_t n = *pos;
429 	unsigned bucket, entry;
430 	int toss = (seq->op == &format4_seq_ops);
431 
432 	bucket = n >> 32;
433 	entry = n & ((1LL << 32) - 1);
434 
435 	if (bucket >= ls->ls_rsbtbl_size)
436 		return NULL;
437 
438 	ri = kzalloc(sizeof(*ri), GFP_NOFS);
439 	if (!ri)
440 		return NULL;
441 	if (n == 0)
442 		ri->header = 1;
443 	if (seq->op == &format1_seq_ops)
444 		ri->format = 1;
445 	if (seq->op == &format2_seq_ops)
446 		ri->format = 2;
447 	if (seq->op == &format3_seq_ops)
448 		ri->format = 3;
449 	if (seq->op == &format4_seq_ops)
450 		ri->format = 4;
451 
452 	tree = toss ? &ls->ls_rsbtbl[bucket].toss : &ls->ls_rsbtbl[bucket].keep;
453 
454 	spin_lock(&ls->ls_rsbtbl[bucket].lock);
455 	if (!RB_EMPTY_ROOT(tree)) {
456 		for (node = rb_first(tree); node; node = rb_next(node)) {
457 			r = rb_entry(node, struct dlm_rsb, res_hashnode);
458 			if (!entry--) {
459 				dlm_hold_rsb(r);
460 				ri->rsb = r;
461 				ri->bucket = bucket;
462 				spin_unlock(&ls->ls_rsbtbl[bucket].lock);
463 				return ri;
464 			}
465 		}
466 	}
467 	spin_unlock(&ls->ls_rsbtbl[bucket].lock);
468 
469 	/*
470 	 * move to the first rsb in the next non-empty bucket
471 	 */
472 
473 	/* zero the entry */
474 	n &= ~((1LL << 32) - 1);
475 
476 	while (1) {
477 		bucket++;
478 		n += 1LL << 32;
479 
480 		if (bucket >= ls->ls_rsbtbl_size) {
481 			kfree(ri);
482 			return NULL;
483 		}
484 		tree = toss ? &ls->ls_rsbtbl[bucket].toss : &ls->ls_rsbtbl[bucket].keep;
485 
486 		spin_lock(&ls->ls_rsbtbl[bucket].lock);
487 		if (!RB_EMPTY_ROOT(tree)) {
488 			node = rb_first(tree);
489 			r = rb_entry(node, struct dlm_rsb, res_hashnode);
490 			dlm_hold_rsb(r);
491 			ri->rsb = r;
492 			ri->bucket = bucket;
493 			spin_unlock(&ls->ls_rsbtbl[bucket].lock);
494 			*pos = n;
495 			return ri;
496 		}
497 		spin_unlock(&ls->ls_rsbtbl[bucket].lock);
498 	}
499 }
500 
501 static void *table_seq_next(struct seq_file *seq, void *iter_ptr, loff_t *pos)
502 {
503 	struct dlm_ls *ls = seq->private;
504 	struct rsbtbl_iter *ri = iter_ptr;
505 	struct rb_root *tree;
506 	struct rb_node *next;
507 	struct dlm_rsb *r, *rp;
508 	loff_t n = *pos;
509 	unsigned bucket;
510 	int toss = (seq->op == &format4_seq_ops);
511 
512 	bucket = n >> 32;
513 
514 	/*
515 	 * move to the next rsb in the same bucket
516 	 */
517 
518 	spin_lock(&ls->ls_rsbtbl[bucket].lock);
519 	rp = ri->rsb;
520 	next = rb_next(&rp->res_hashnode);
521 
522 	if (next) {
523 		r = rb_entry(next, struct dlm_rsb, res_hashnode);
524 		dlm_hold_rsb(r);
525 		ri->rsb = r;
526 		spin_unlock(&ls->ls_rsbtbl[bucket].lock);
527 		dlm_put_rsb(rp);
528 		++*pos;
529 		return ri;
530 	}
531 	spin_unlock(&ls->ls_rsbtbl[bucket].lock);
532 	dlm_put_rsb(rp);
533 
534 	/*
535 	 * move to the first rsb in the next non-empty bucket
536 	 */
537 
538 	/* zero the entry */
539 	n &= ~((1LL << 32) - 1);
540 
541 	while (1) {
542 		bucket++;
543 		n += 1LL << 32;
544 
545 		if (bucket >= ls->ls_rsbtbl_size) {
546 			kfree(ri);
547 			return NULL;
548 		}
549 		tree = toss ? &ls->ls_rsbtbl[bucket].toss : &ls->ls_rsbtbl[bucket].keep;
550 
551 		spin_lock(&ls->ls_rsbtbl[bucket].lock);
552 		if (!RB_EMPTY_ROOT(tree)) {
553 			next = rb_first(tree);
554 			r = rb_entry(next, struct dlm_rsb, res_hashnode);
555 			dlm_hold_rsb(r);
556 			ri->rsb = r;
557 			ri->bucket = bucket;
558 			spin_unlock(&ls->ls_rsbtbl[bucket].lock);
559 			*pos = n;
560 			return ri;
561 		}
562 		spin_unlock(&ls->ls_rsbtbl[bucket].lock);
563 	}
564 }
565 
566 static void table_seq_stop(struct seq_file *seq, void *iter_ptr)
567 {
568 	struct rsbtbl_iter *ri = iter_ptr;
569 
570 	if (ri) {
571 		dlm_put_rsb(ri->rsb);
572 		kfree(ri);
573 	}
574 }
575 
576 static const struct seq_operations format1_seq_ops = {
577 	.start = table_seq_start,
578 	.next  = table_seq_next,
579 	.stop  = table_seq_stop,
580 	.show  = table_seq_show,
581 };
582 
583 static const struct seq_operations format2_seq_ops = {
584 	.start = table_seq_start,
585 	.next  = table_seq_next,
586 	.stop  = table_seq_stop,
587 	.show  = table_seq_show,
588 };
589 
590 static const struct seq_operations format3_seq_ops = {
591 	.start = table_seq_start,
592 	.next  = table_seq_next,
593 	.stop  = table_seq_stop,
594 	.show  = table_seq_show,
595 };
596 
597 static const struct seq_operations format4_seq_ops = {
598 	.start = table_seq_start,
599 	.next  = table_seq_next,
600 	.stop  = table_seq_stop,
601 	.show  = table_seq_show,
602 };
603 
604 static const struct file_operations format1_fops;
605 static const struct file_operations format2_fops;
606 static const struct file_operations format3_fops;
607 static const struct file_operations format4_fops;
608 
609 static int table_open1(struct inode *inode, struct file *file)
610 {
611 	struct seq_file *seq;
612 	int ret;
613 
614 	ret = seq_open(file, &format1_seq_ops);
615 	if (ret)
616 		return ret;
617 
618 	seq = file->private_data;
619 	seq->private = inode->i_private; /* the dlm_ls */
620 	return 0;
621 }
622 
623 static int table_open2(struct inode *inode, struct file *file)
624 {
625 	struct seq_file *seq;
626 	int ret;
627 
628 	ret = seq_open(file, &format2_seq_ops);
629 	if (ret)
630 		return ret;
631 
632 	seq = file->private_data;
633 	seq->private = inode->i_private; /* the dlm_ls */
634 	return 0;
635 }
636 
637 static int table_open3(struct inode *inode, struct file *file)
638 {
639 	struct seq_file *seq;
640 	int ret;
641 
642 	ret = seq_open(file, &format3_seq_ops);
643 	if (ret)
644 		return ret;
645 
646 	seq = file->private_data;
647 	seq->private = inode->i_private; /* the dlm_ls */
648 	return 0;
649 }
650 
651 static int table_open4(struct inode *inode, struct file *file)
652 {
653 	struct seq_file *seq;
654 	int ret;
655 
656 	ret = seq_open(file, &format4_seq_ops);
657 	if (ret)
658 		return ret;
659 
660 	seq = file->private_data;
661 	seq->private = inode->i_private; /* the dlm_ls */
662 	return 0;
663 }
664 
665 static const struct file_operations format1_fops = {
666 	.owner   = THIS_MODULE,
667 	.open    = table_open1,
668 	.read    = seq_read,
669 	.llseek  = seq_lseek,
670 	.release = seq_release
671 };
672 
673 static const struct file_operations format2_fops = {
674 	.owner   = THIS_MODULE,
675 	.open    = table_open2,
676 	.read    = seq_read,
677 	.llseek  = seq_lseek,
678 	.release = seq_release
679 };
680 
681 static const struct file_operations format3_fops = {
682 	.owner   = THIS_MODULE,
683 	.open    = table_open3,
684 	.read    = seq_read,
685 	.llseek  = seq_lseek,
686 	.release = seq_release
687 };
688 
689 static const struct file_operations format4_fops = {
690 	.owner   = THIS_MODULE,
691 	.open    = table_open4,
692 	.read    = seq_read,
693 	.llseek  = seq_lseek,
694 	.release = seq_release
695 };
696 
697 /*
698  * dump lkb's on the ls_waiters list
699  */
700 static ssize_t waiters_read(struct file *file, char __user *userbuf,
701 			    size_t count, loff_t *ppos)
702 {
703 	struct dlm_ls *ls = file->private_data;
704 	struct dlm_lkb *lkb;
705 	size_t len = DLM_DEBUG_BUF_LEN, pos = 0, ret, rv;
706 
707 	mutex_lock(&debug_buf_lock);
708 	mutex_lock(&ls->ls_waiters_mutex);
709 	memset(debug_buf, 0, sizeof(debug_buf));
710 
711 	list_for_each_entry(lkb, &ls->ls_waiters, lkb_wait_reply) {
712 		ret = snprintf(debug_buf + pos, len - pos, "%x %d %d %s\n",
713 			       lkb->lkb_id, lkb->lkb_wait_type,
714 			       lkb->lkb_nodeid, lkb->lkb_resource->res_name);
715 		if (ret >= len - pos)
716 			break;
717 		pos += ret;
718 	}
719 	mutex_unlock(&ls->ls_waiters_mutex);
720 
721 	rv = simple_read_from_buffer(userbuf, count, ppos, debug_buf, pos);
722 	mutex_unlock(&debug_buf_lock);
723 	return rv;
724 }
725 
726 static const struct file_operations waiters_fops = {
727 	.owner   = THIS_MODULE,
728 	.open    = simple_open,
729 	.read    = waiters_read,
730 	.llseek  = default_llseek,
731 };
732 
733 void dlm_delete_debug_file(struct dlm_ls *ls)
734 {
735 	debugfs_remove(ls->ls_debug_rsb_dentry);
736 	debugfs_remove(ls->ls_debug_waiters_dentry);
737 	debugfs_remove(ls->ls_debug_locks_dentry);
738 	debugfs_remove(ls->ls_debug_all_dentry);
739 	debugfs_remove(ls->ls_debug_toss_dentry);
740 }
741 
742 int dlm_create_debug_file(struct dlm_ls *ls)
743 {
744 	char name[DLM_LOCKSPACE_LEN + 8];
745 
746 	/* format 1 */
747 
748 	ls->ls_debug_rsb_dentry = debugfs_create_file(ls->ls_name,
749 						      S_IFREG | S_IRUGO,
750 						      dlm_root,
751 						      ls,
752 						      &format1_fops);
753 	if (!ls->ls_debug_rsb_dentry)
754 		goto fail;
755 
756 	/* format 2 */
757 
758 	memset(name, 0, sizeof(name));
759 	snprintf(name, DLM_LOCKSPACE_LEN + 8, "%s_locks", ls->ls_name);
760 
761 	ls->ls_debug_locks_dentry = debugfs_create_file(name,
762 							S_IFREG | S_IRUGO,
763 							dlm_root,
764 							ls,
765 							&format2_fops);
766 	if (!ls->ls_debug_locks_dentry)
767 		goto fail;
768 
769 	/* format 3 */
770 
771 	memset(name, 0, sizeof(name));
772 	snprintf(name, DLM_LOCKSPACE_LEN + 8, "%s_all", ls->ls_name);
773 
774 	ls->ls_debug_all_dentry = debugfs_create_file(name,
775 						      S_IFREG | S_IRUGO,
776 						      dlm_root,
777 						      ls,
778 						      &format3_fops);
779 	if (!ls->ls_debug_all_dentry)
780 		goto fail;
781 
782 	/* format 4 */
783 
784 	memset(name, 0, sizeof(name));
785 	snprintf(name, DLM_LOCKSPACE_LEN + 8, "%s_toss", ls->ls_name);
786 
787 	ls->ls_debug_toss_dentry = debugfs_create_file(name,
788 						       S_IFREG | S_IRUGO,
789 						       dlm_root,
790 						       ls,
791 						       &format4_fops);
792 	if (!ls->ls_debug_toss_dentry)
793 		goto fail;
794 
795 	memset(name, 0, sizeof(name));
796 	snprintf(name, DLM_LOCKSPACE_LEN + 8, "%s_waiters", ls->ls_name);
797 
798 	ls->ls_debug_waiters_dentry = debugfs_create_file(name,
799 							  S_IFREG | S_IRUGO,
800 							  dlm_root,
801 							  ls,
802 							  &waiters_fops);
803 	if (!ls->ls_debug_waiters_dentry)
804 		goto fail;
805 
806 	return 0;
807 
808  fail:
809 	dlm_delete_debug_file(ls);
810 	return -ENOMEM;
811 }
812 
813 int __init dlm_register_debugfs(void)
814 {
815 	mutex_init(&debug_buf_lock);
816 	dlm_root = debugfs_create_dir("dlm", NULL);
817 	return dlm_root ? 0 : -ENOMEM;
818 }
819 
820 void dlm_unregister_debugfs(void)
821 {
822 	debugfs_remove(dlm_root);
823 }
824 
825