dlm: fix QUECVT when convert queue is empty
[linux-2.6.git] / fs / dlm / debug_fs.c
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 rb_node *node;
397         struct dlm_ls *ls = seq->private;
398         struct rsbtbl_iter *ri;
399         struct dlm_rsb *r;
400         loff_t n = *pos;
401         unsigned bucket, entry;
402
403         bucket = n >> 32;
404         entry = n & ((1LL << 32) - 1);
405
406         if (bucket >= ls->ls_rsbtbl_size)
407                 return NULL;
408
409         ri = kzalloc(sizeof(struct rsbtbl_iter), GFP_NOFS);
410         if (!ri)
411                 return NULL;
412         if (n == 0)
413                 ri->header = 1;
414         if (seq->op == &format1_seq_ops)
415                 ri->format = 1;
416         if (seq->op == &format2_seq_ops)
417                 ri->format = 2;
418         if (seq->op == &format3_seq_ops)
419                 ri->format = 3;
420
421         spin_lock(&ls->ls_rsbtbl[bucket].lock);
422         if (!RB_EMPTY_ROOT(&ls->ls_rsbtbl[bucket].keep)) {
423                 for (node = rb_first(&ls->ls_rsbtbl[bucket].keep); node;
424                      node = rb_next(node)) {
425                         r = rb_entry(node, struct dlm_rsb, res_hashnode);
426                         if (!entry--) {
427                                 dlm_hold_rsb(r);
428                                 ri->rsb = r;
429                                 ri->bucket = bucket;
430                                 spin_unlock(&ls->ls_rsbtbl[bucket].lock);
431                                 return ri;
432                         }
433                 }
434         }
435         spin_unlock(&ls->ls_rsbtbl[bucket].lock);
436
437         /*
438          * move to the first rsb in the next non-empty bucket
439          */
440
441         /* zero the entry */
442         n &= ~((1LL << 32) - 1);
443
444         while (1) {
445                 bucket++;
446                 n += 1LL << 32;
447
448                 if (bucket >= ls->ls_rsbtbl_size) {
449                         kfree(ri);
450                         return NULL;
451                 }
452
453                 spin_lock(&ls->ls_rsbtbl[bucket].lock);
454                 if (!RB_EMPTY_ROOT(&ls->ls_rsbtbl[bucket].keep)) {
455                         node = rb_first(&ls->ls_rsbtbl[bucket].keep);
456                         r = rb_entry(node, struct dlm_rsb, res_hashnode);
457                         dlm_hold_rsb(r);
458                         ri->rsb = r;
459                         ri->bucket = bucket;
460                         spin_unlock(&ls->ls_rsbtbl[bucket].lock);
461                         *pos = n;
462                         return ri;
463                 }
464                 spin_unlock(&ls->ls_rsbtbl[bucket].lock);
465         }
466 }
467
468 static void *table_seq_next(struct seq_file *seq, void *iter_ptr, loff_t *pos)
469 {
470         struct dlm_ls *ls = seq->private;
471         struct rsbtbl_iter *ri = iter_ptr;
472         struct rb_node *next;
473         struct dlm_rsb *r, *rp;
474         loff_t n = *pos;
475         unsigned bucket;
476
477         bucket = n >> 32;
478
479         /*
480          * move to the next rsb in the same bucket
481          */
482
483         spin_lock(&ls->ls_rsbtbl[bucket].lock);
484         rp = ri->rsb;
485         next = rb_next(&rp->res_hashnode);
486
487         if (next) {
488                 r = rb_entry(next, struct dlm_rsb, res_hashnode);
489                 dlm_hold_rsb(r);
490                 ri->rsb = r;
491                 spin_unlock(&ls->ls_rsbtbl[bucket].lock);
492                 dlm_put_rsb(rp);
493                 ++*pos;
494                 return ri;
495         }
496         spin_unlock(&ls->ls_rsbtbl[bucket].lock);
497         dlm_put_rsb(rp);
498
499         /*
500          * move to the first rsb in the next non-empty bucket
501          */
502
503         /* zero the entry */
504         n &= ~((1LL << 32) - 1);
505
506         while (1) {
507                 bucket++;
508                 n += 1LL << 32;
509
510                 if (bucket >= ls->ls_rsbtbl_size) {
511                         kfree(ri);
512                         return NULL;
513                 }
514
515                 spin_lock(&ls->ls_rsbtbl[bucket].lock);
516                 if (!RB_EMPTY_ROOT(&ls->ls_rsbtbl[bucket].keep)) {
517                         next = rb_first(&ls->ls_rsbtbl[bucket].keep);
518                         r = rb_entry(next, struct dlm_rsb, res_hashnode);
519                         dlm_hold_rsb(r);
520                         ri->rsb = r;
521                         ri->bucket = bucket;
522                         spin_unlock(&ls->ls_rsbtbl[bucket].lock);
523                         *pos = n;
524                         return ri;
525                 }
526                 spin_unlock(&ls->ls_rsbtbl[bucket].lock);
527         }
528 }
529
530 static void table_seq_stop(struct seq_file *seq, void *iter_ptr)
531 {
532         struct rsbtbl_iter *ri = iter_ptr;
533
534         if (ri) {
535                 dlm_put_rsb(ri->rsb);
536                 kfree(ri);
537         }
538 }
539
540 static const struct seq_operations format1_seq_ops = {
541         .start = table_seq_start,
542         .next  = table_seq_next,
543         .stop  = table_seq_stop,
544         .show  = table_seq_show,
545 };
546
547 static const struct seq_operations format2_seq_ops = {
548         .start = table_seq_start,
549         .next  = table_seq_next,
550         .stop  = table_seq_stop,
551         .show  = table_seq_show,
552 };
553
554 static const struct seq_operations format3_seq_ops = {
555         .start = table_seq_start,
556         .next  = table_seq_next,
557         .stop  = table_seq_stop,
558         .show  = table_seq_show,
559 };
560
561 static const struct file_operations format1_fops;
562 static const struct file_operations format2_fops;
563 static const struct file_operations format3_fops;
564
565 static int table_open(struct inode *inode, struct file *file)
566 {
567         struct seq_file *seq;
568         int ret = -1;
569
570         if (file->f_op == &format1_fops)
571                 ret = seq_open(file, &format1_seq_ops);
572         else if (file->f_op == &format2_fops)
573                 ret = seq_open(file, &format2_seq_ops);
574         else if (file->f_op == &format3_fops)
575                 ret = seq_open(file, &format3_seq_ops);
576
577         if (ret)
578                 return ret;
579
580         seq = file->private_data;
581         seq->private = inode->i_private; /* the dlm_ls */
582         return 0;
583 }
584
585 static const struct file_operations format1_fops = {
586         .owner   = THIS_MODULE,
587         .open    = table_open,
588         .read    = seq_read,
589         .llseek  = seq_lseek,
590         .release = seq_release
591 };
592
593 static const struct file_operations format2_fops = {
594         .owner   = THIS_MODULE,
595         .open    = table_open,
596         .read    = seq_read,
597         .llseek  = seq_lseek,
598         .release = seq_release
599 };
600
601 static const struct file_operations format3_fops = {
602         .owner   = THIS_MODULE,
603         .open    = table_open,
604         .read    = seq_read,
605         .llseek  = seq_lseek,
606         .release = seq_release
607 };
608
609 /*
610  * dump lkb's on the ls_waiters list
611  */
612 static ssize_t waiters_read(struct file *file, char __user *userbuf,
613                             size_t count, loff_t *ppos)
614 {
615         struct dlm_ls *ls = file->private_data;
616         struct dlm_lkb *lkb;
617         size_t len = DLM_DEBUG_BUF_LEN, pos = 0, ret, rv;
618
619         mutex_lock(&debug_buf_lock);
620         mutex_lock(&ls->ls_waiters_mutex);
621         memset(debug_buf, 0, sizeof(debug_buf));
622
623         list_for_each_entry(lkb, &ls->ls_waiters, lkb_wait_reply) {
624                 ret = snprintf(debug_buf + pos, len - pos, "%x %d %d %s\n",
625                                lkb->lkb_id, lkb->lkb_wait_type,
626                                lkb->lkb_nodeid, lkb->lkb_resource->res_name);
627                 if (ret >= len - pos)
628                         break;
629                 pos += ret;
630         }
631         mutex_unlock(&ls->ls_waiters_mutex);
632
633         rv = simple_read_from_buffer(userbuf, count, ppos, debug_buf, pos);
634         mutex_unlock(&debug_buf_lock);
635         return rv;
636 }
637
638 static const struct file_operations waiters_fops = {
639         .owner   = THIS_MODULE,
640         .open    = simple_open,
641         .read    = waiters_read,
642         .llseek  = default_llseek,
643 };
644
645 void dlm_delete_debug_file(struct dlm_ls *ls)
646 {
647         if (ls->ls_debug_rsb_dentry)
648                 debugfs_remove(ls->ls_debug_rsb_dentry);
649         if (ls->ls_debug_waiters_dentry)
650                 debugfs_remove(ls->ls_debug_waiters_dentry);
651         if (ls->ls_debug_locks_dentry)
652                 debugfs_remove(ls->ls_debug_locks_dentry);
653         if (ls->ls_debug_all_dentry)
654                 debugfs_remove(ls->ls_debug_all_dentry);
655 }
656
657 int dlm_create_debug_file(struct dlm_ls *ls)
658 {
659         char name[DLM_LOCKSPACE_LEN+8];
660
661         /* format 1 */
662
663         ls->ls_debug_rsb_dentry = debugfs_create_file(ls->ls_name,
664                                                       S_IFREG | S_IRUGO,
665                                                       dlm_root,
666                                                       ls,
667                                                       &format1_fops);
668         if (!ls->ls_debug_rsb_dentry)
669                 goto fail;
670
671         /* format 2 */
672
673         memset(name, 0, sizeof(name));
674         snprintf(name, DLM_LOCKSPACE_LEN+8, "%s_locks", ls->ls_name);
675
676         ls->ls_debug_locks_dentry = debugfs_create_file(name,
677                                                         S_IFREG | S_IRUGO,
678                                                         dlm_root,
679                                                         ls,
680                                                         &format2_fops);
681         if (!ls->ls_debug_locks_dentry)
682                 goto fail;
683
684         /* format 3 */
685
686         memset(name, 0, sizeof(name));
687         snprintf(name, DLM_LOCKSPACE_LEN+8, "%s_all", ls->ls_name);
688
689         ls->ls_debug_all_dentry = debugfs_create_file(name,
690                                                       S_IFREG | S_IRUGO,
691                                                       dlm_root,
692                                                       ls,
693                                                       &format3_fops);
694         if (!ls->ls_debug_all_dentry)
695                 goto fail;
696
697         memset(name, 0, sizeof(name));
698         snprintf(name, DLM_LOCKSPACE_LEN+8, "%s_waiters", ls->ls_name);
699
700         ls->ls_debug_waiters_dentry = debugfs_create_file(name,
701                                                           S_IFREG | S_IRUGO,
702                                                           dlm_root,
703                                                           ls,
704                                                           &waiters_fops);
705         if (!ls->ls_debug_waiters_dentry)
706                 goto fail;
707
708         return 0;
709
710  fail:
711         dlm_delete_debug_file(ls);
712         return -ENOMEM;
713 }
714
715 int __init dlm_register_debugfs(void)
716 {
717         mutex_init(&debug_buf_lock);
718         dlm_root = debugfs_create_dir("dlm", NULL);
719         return dlm_root ? 0 : -ENOMEM;
720 }
721
722 void dlm_unregister_debugfs(void)
723 {
724         debugfs_remove(dlm_root);
725 }
726