Merge branch 'bjorn-notify' into release
[pandora-kernel.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
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