[GFS2] Clean up inode number handling
[linux-2.6] / fs / gfs2 / glock.c
1 /*
2  * Copyright (C) Sistina Software, Inc.  1997-2003 All rights reserved.
3  * Copyright (C) 2004-2006 Red Hat, Inc.  All rights reserved.
4  *
5  * This copyrighted material is made available to anyone wishing to use,
6  * modify, copy, or redistribute it subject to the terms and conditions
7  * of the GNU General Public License version 2.
8  */
9
10 #include <linux/sched.h>
11 #include <linux/slab.h>
12 #include <linux/spinlock.h>
13 #include <linux/completion.h>
14 #include <linux/buffer_head.h>
15 #include <linux/delay.h>
16 #include <linux/sort.h>
17 #include <linux/jhash.h>
18 #include <linux/kallsyms.h>
19 #include <linux/gfs2_ondisk.h>
20 #include <linux/list.h>
21 #include <linux/lm_interface.h>
22 #include <linux/wait.h>
23 #include <linux/module.h>
24 #include <linux/rwsem.h>
25 #include <asm/uaccess.h>
26 #include <linux/seq_file.h>
27 #include <linux/debugfs.h>
28 #include <linux/module.h>
29 #include <linux/kallsyms.h>
30
31 #include "gfs2.h"
32 #include "incore.h"
33 #include "glock.h"
34 #include "glops.h"
35 #include "inode.h"
36 #include "lm.h"
37 #include "lops.h"
38 #include "meta_io.h"
39 #include "quota.h"
40 #include "super.h"
41 #include "util.h"
42
43 struct gfs2_gl_hash_bucket {
44         struct hlist_head hb_list;
45 };
46
47 struct glock_iter {
48         int hash;                     /* hash bucket index         */
49         struct gfs2_sbd *sdp;         /* incore superblock         */
50         struct gfs2_glock *gl;        /* current glock struct      */
51         struct hlist_head *hb_list;   /* current hash bucket ptr   */
52         struct seq_file *seq;         /* sequence file for debugfs */
53         char string[512];             /* scratch space             */
54 };
55
56 typedef void (*glock_examiner) (struct gfs2_glock * gl);
57
58 static int gfs2_dump_lockstate(struct gfs2_sbd *sdp);
59 static int dump_glock(struct glock_iter *gi, struct gfs2_glock *gl);
60 static void gfs2_glock_xmote_th(struct gfs2_glock *gl, struct gfs2_holder *gh);
61 static void gfs2_glock_drop_th(struct gfs2_glock *gl);
62 static DECLARE_RWSEM(gfs2_umount_flush_sem);
63 static struct dentry *gfs2_root;
64
65 #define GFS2_GL_HASH_SHIFT      15
66 #define GFS2_GL_HASH_SIZE       (1 << GFS2_GL_HASH_SHIFT)
67 #define GFS2_GL_HASH_MASK       (GFS2_GL_HASH_SIZE - 1)
68
69 static struct gfs2_gl_hash_bucket gl_hash_table[GFS2_GL_HASH_SIZE];
70 static struct dentry *gfs2_root;
71
72 /*
73  * Despite what you might think, the numbers below are not arbitrary :-)
74  * They are taken from the ipv4 routing hash code, which is well tested
75  * and thus should be nearly optimal. Later on we might tweek the numbers
76  * but for now this should be fine.
77  *
78  * The reason for putting the locks in a separate array from the list heads
79  * is that we can have fewer locks than list heads and save memory. We use
80  * the same hash function for both, but with a different hash mask.
81  */
82 #if defined(CONFIG_SMP) || defined(CONFIG_DEBUG_SPINLOCK) || \
83         defined(CONFIG_PROVE_LOCKING)
84
85 #ifdef CONFIG_LOCKDEP
86 # define GL_HASH_LOCK_SZ        256
87 #else
88 # if NR_CPUS >= 32
89 #  define GL_HASH_LOCK_SZ       4096
90 # elif NR_CPUS >= 16
91 #  define GL_HASH_LOCK_SZ       2048
92 # elif NR_CPUS >= 8
93 #  define GL_HASH_LOCK_SZ       1024
94 # elif NR_CPUS >= 4
95 #  define GL_HASH_LOCK_SZ       512
96 # else
97 #  define GL_HASH_LOCK_SZ       256
98 # endif
99 #endif
100
101 /* We never want more locks than chains */
102 #if GFS2_GL_HASH_SIZE < GL_HASH_LOCK_SZ
103 # undef GL_HASH_LOCK_SZ
104 # define GL_HASH_LOCK_SZ GFS2_GL_HASH_SIZE
105 #endif
106
107 static rwlock_t gl_hash_locks[GL_HASH_LOCK_SZ];
108
109 static inline rwlock_t *gl_lock_addr(unsigned int x)
110 {
111         return &gl_hash_locks[x & (GL_HASH_LOCK_SZ-1)];
112 }
113 #else /* not SMP, so no spinlocks required */
114 static inline rwlock_t *gl_lock_addr(unsigned int x)
115 {
116         return NULL;
117 }
118 #endif
119
120 /**
121  * relaxed_state_ok - is a requested lock compatible with the current lock mode?
122  * @actual: the current state of the lock
123  * @requested: the lock state that was requested by the caller
124  * @flags: the modifier flags passed in by the caller
125  *
126  * Returns: 1 if the locks are compatible, 0 otherwise
127  */
128
129 static inline int relaxed_state_ok(unsigned int actual, unsigned requested,
130                                    int flags)
131 {
132         if (actual == requested)
133                 return 1;
134
135         if (flags & GL_EXACT)
136                 return 0;
137
138         if (actual == LM_ST_EXCLUSIVE && requested == LM_ST_SHARED)
139                 return 1;
140
141         if (actual != LM_ST_UNLOCKED && (flags & LM_FLAG_ANY))
142                 return 1;
143
144         return 0;
145 }
146
147 /**
148  * gl_hash() - Turn glock number into hash bucket number
149  * @lock: The glock number
150  *
151  * Returns: The number of the corresponding hash bucket
152  */
153
154 static unsigned int gl_hash(const struct gfs2_sbd *sdp,
155                             const struct lm_lockname *name)
156 {
157         unsigned int h;
158
159         h = jhash(&name->ln_number, sizeof(u64), 0);
160         h = jhash(&name->ln_type, sizeof(unsigned int), h);
161         h = jhash(&sdp, sizeof(struct gfs2_sbd *), h);
162         h &= GFS2_GL_HASH_MASK;
163
164         return h;
165 }
166
167 /**
168  * glock_free() - Perform a few checks and then release struct gfs2_glock
169  * @gl: The glock to release
170  *
171  * Also calls lock module to release its internal structure for this glock.
172  *
173  */
174
175 static void glock_free(struct gfs2_glock *gl)
176 {
177         struct gfs2_sbd *sdp = gl->gl_sbd;
178         struct inode *aspace = gl->gl_aspace;
179
180         gfs2_lm_put_lock(sdp, gl->gl_lock);
181
182         if (aspace)
183                 gfs2_aspace_put(aspace);
184
185         kmem_cache_free(gfs2_glock_cachep, gl);
186 }
187
188 /**
189  * gfs2_glock_hold() - increment reference count on glock
190  * @gl: The glock to hold
191  *
192  */
193
194 void gfs2_glock_hold(struct gfs2_glock *gl)
195 {
196         atomic_inc(&gl->gl_ref);
197 }
198
199 /**
200  * gfs2_glock_put() - Decrement reference count on glock
201  * @gl: The glock to put
202  *
203  */
204
205 int gfs2_glock_put(struct gfs2_glock *gl)
206 {
207         int rv = 0;
208         struct gfs2_sbd *sdp = gl->gl_sbd;
209
210         write_lock(gl_lock_addr(gl->gl_hash));
211         if (atomic_dec_and_test(&gl->gl_ref)) {
212                 hlist_del(&gl->gl_list);
213                 write_unlock(gl_lock_addr(gl->gl_hash));
214                 BUG_ON(spin_is_locked(&gl->gl_spin));
215                 gfs2_assert(sdp, gl->gl_state == LM_ST_UNLOCKED);
216                 gfs2_assert(sdp, list_empty(&gl->gl_reclaim));
217                 gfs2_assert(sdp, list_empty(&gl->gl_holders));
218                 gfs2_assert(sdp, list_empty(&gl->gl_waiters1));
219                 gfs2_assert(sdp, list_empty(&gl->gl_waiters3));
220                 glock_free(gl);
221                 rv = 1;
222                 goto out;
223         }
224         write_unlock(gl_lock_addr(gl->gl_hash));
225 out:
226         return rv;
227 }
228
229 /**
230  * search_bucket() - Find struct gfs2_glock by lock number
231  * @bucket: the bucket to search
232  * @name: The lock name
233  *
234  * Returns: NULL, or the struct gfs2_glock with the requested number
235  */
236
237 static struct gfs2_glock *search_bucket(unsigned int hash,
238                                         const struct gfs2_sbd *sdp,
239                                         const struct lm_lockname *name)
240 {
241         struct gfs2_glock *gl;
242         struct hlist_node *h;
243
244         hlist_for_each_entry(gl, h, &gl_hash_table[hash].hb_list, gl_list) {
245                 if (!lm_name_equal(&gl->gl_name, name))
246                         continue;
247                 if (gl->gl_sbd != sdp)
248                         continue;
249
250                 atomic_inc(&gl->gl_ref);
251
252                 return gl;
253         }
254
255         return NULL;
256 }
257
258 /**
259  * gfs2_glock_find() - Find glock by lock number
260  * @sdp: The GFS2 superblock
261  * @name: The lock name
262  *
263  * Returns: NULL, or the struct gfs2_glock with the requested number
264  */
265
266 static struct gfs2_glock *gfs2_glock_find(const struct gfs2_sbd *sdp,
267                                           const struct lm_lockname *name)
268 {
269         unsigned int hash = gl_hash(sdp, name);
270         struct gfs2_glock *gl;
271
272         read_lock(gl_lock_addr(hash));
273         gl = search_bucket(hash, sdp, name);
274         read_unlock(gl_lock_addr(hash));
275
276         return gl;
277 }
278
279 /**
280  * gfs2_glock_get() - Get a glock, or create one if one doesn't exist
281  * @sdp: The GFS2 superblock
282  * @number: the lock number
283  * @glops: The glock_operations to use
284  * @create: If 0, don't create the glock if it doesn't exist
285  * @glp: the glock is returned here
286  *
287  * This does not lock a glock, just finds/creates structures for one.
288  *
289  * Returns: errno
290  */
291
292 int gfs2_glock_get(struct gfs2_sbd *sdp, u64 number,
293                    const struct gfs2_glock_operations *glops, int create,
294                    struct gfs2_glock **glp)
295 {
296         struct lm_lockname name = { .ln_number = number, .ln_type = glops->go_type };
297         struct gfs2_glock *gl, *tmp;
298         unsigned int hash = gl_hash(sdp, &name);
299         int error;
300
301         read_lock(gl_lock_addr(hash));
302         gl = search_bucket(hash, sdp, &name);
303         read_unlock(gl_lock_addr(hash));
304
305         if (gl || !create) {
306                 *glp = gl;
307                 return 0;
308         }
309
310         gl = kmem_cache_alloc(gfs2_glock_cachep, GFP_KERNEL);
311         if (!gl)
312                 return -ENOMEM;
313
314         gl->gl_flags = 0;
315         gl->gl_name = name;
316         atomic_set(&gl->gl_ref, 1);
317         gl->gl_state = LM_ST_UNLOCKED;
318         gl->gl_hash = hash;
319         gl->gl_owner_pid = 0;
320         gl->gl_ip = 0;
321         gl->gl_ops = glops;
322         gl->gl_req_gh = NULL;
323         gl->gl_req_bh = NULL;
324         gl->gl_vn = 0;
325         gl->gl_stamp = jiffies;
326         gl->gl_object = NULL;
327         gl->gl_sbd = sdp;
328         gl->gl_aspace = NULL;
329         lops_init_le(&gl->gl_le, &gfs2_glock_lops);
330
331         /* If this glock protects actual on-disk data or metadata blocks,
332            create a VFS inode to manage the pages/buffers holding them. */
333         if (glops == &gfs2_inode_glops || glops == &gfs2_rgrp_glops) {
334                 gl->gl_aspace = gfs2_aspace_get(sdp);
335                 if (!gl->gl_aspace) {
336                         error = -ENOMEM;
337                         goto fail;
338                 }
339         }
340
341         error = gfs2_lm_get_lock(sdp, &name, &gl->gl_lock);
342         if (error)
343                 goto fail_aspace;
344
345         write_lock(gl_lock_addr(hash));
346         tmp = search_bucket(hash, sdp, &name);
347         if (tmp) {
348                 write_unlock(gl_lock_addr(hash));
349                 glock_free(gl);
350                 gl = tmp;
351         } else {
352                 hlist_add_head(&gl->gl_list, &gl_hash_table[hash].hb_list);
353                 write_unlock(gl_lock_addr(hash));
354         }
355
356         *glp = gl;
357
358         return 0;
359
360 fail_aspace:
361         if (gl->gl_aspace)
362                 gfs2_aspace_put(gl->gl_aspace);
363 fail:
364         kmem_cache_free(gfs2_glock_cachep, gl);
365         return error;
366 }
367
368 /**
369  * gfs2_holder_init - initialize a struct gfs2_holder in the default way
370  * @gl: the glock
371  * @state: the state we're requesting
372  * @flags: the modifier flags
373  * @gh: the holder structure
374  *
375  */
376
377 void gfs2_holder_init(struct gfs2_glock *gl, unsigned int state, unsigned flags,
378                       struct gfs2_holder *gh)
379 {
380         INIT_LIST_HEAD(&gh->gh_list);
381         gh->gh_gl = gl;
382         gh->gh_ip = (unsigned long)__builtin_return_address(0);
383         gh->gh_owner_pid = current->pid;
384         gh->gh_state = state;
385         gh->gh_flags = flags;
386         gh->gh_error = 0;
387         gh->gh_iflags = 0;
388         gfs2_glock_hold(gl);
389 }
390
391 /**
392  * gfs2_holder_reinit - reinitialize a struct gfs2_holder so we can requeue it
393  * @state: the state we're requesting
394  * @flags: the modifier flags
395  * @gh: the holder structure
396  *
397  * Don't mess with the glock.
398  *
399  */
400
401 void gfs2_holder_reinit(unsigned int state, unsigned flags, struct gfs2_holder *gh)
402 {
403         gh->gh_state = state;
404         gh->gh_flags = flags;
405         gh->gh_iflags = 0;
406         gh->gh_ip = (unsigned long)__builtin_return_address(0);
407 }
408
409 /**
410  * gfs2_holder_uninit - uninitialize a holder structure (drop glock reference)
411  * @gh: the holder structure
412  *
413  */
414
415 void gfs2_holder_uninit(struct gfs2_holder *gh)
416 {
417         gfs2_glock_put(gh->gh_gl);
418         gh->gh_gl = NULL;
419         gh->gh_ip = 0;
420 }
421
422 static void gfs2_holder_wake(struct gfs2_holder *gh)
423 {
424         clear_bit(HIF_WAIT, &gh->gh_iflags);
425         smp_mb();
426         wake_up_bit(&gh->gh_iflags, HIF_WAIT);
427 }
428
429 static int holder_wait(void *word)
430 {
431         schedule();
432         return 0;
433 }
434
435 static void wait_on_holder(struct gfs2_holder *gh)
436 {
437         might_sleep();
438         wait_on_bit(&gh->gh_iflags, HIF_WAIT, holder_wait, TASK_UNINTERRUPTIBLE);
439 }
440
441 /**
442  * rq_mutex - process a mutex request in the queue
443  * @gh: the glock holder
444  *
445  * Returns: 1 if the queue is blocked
446  */
447
448 static int rq_mutex(struct gfs2_holder *gh)
449 {
450         struct gfs2_glock *gl = gh->gh_gl;
451
452         list_del_init(&gh->gh_list);
453         /*  gh->gh_error never examined.  */
454         set_bit(GLF_LOCK, &gl->gl_flags);
455         clear_bit(HIF_WAIT, &gh->gh_iflags);
456         smp_mb();
457         wake_up_bit(&gh->gh_iflags, HIF_WAIT);
458
459         return 1;
460 }
461
462 /**
463  * rq_promote - process a promote request in the queue
464  * @gh: the glock holder
465  *
466  * Acquire a new inter-node lock, or change a lock state to more restrictive.
467  *
468  * Returns: 1 if the queue is blocked
469  */
470
471 static int rq_promote(struct gfs2_holder *gh)
472 {
473         struct gfs2_glock *gl = gh->gh_gl;
474         struct gfs2_sbd *sdp = gl->gl_sbd;
475
476         if (!relaxed_state_ok(gl->gl_state, gh->gh_state, gh->gh_flags)) {
477                 if (list_empty(&gl->gl_holders)) {
478                         gl->gl_req_gh = gh;
479                         set_bit(GLF_LOCK, &gl->gl_flags);
480                         spin_unlock(&gl->gl_spin);
481
482                         if (atomic_read(&sdp->sd_reclaim_count) >
483                             gfs2_tune_get(sdp, gt_reclaim_limit) &&
484                             !(gh->gh_flags & LM_FLAG_PRIORITY)) {
485                                 gfs2_reclaim_glock(sdp);
486                                 gfs2_reclaim_glock(sdp);
487                         }
488
489                         gfs2_glock_xmote_th(gh->gh_gl, gh);
490                         spin_lock(&gl->gl_spin);
491                 }
492                 return 1;
493         }
494
495         if (list_empty(&gl->gl_holders)) {
496                 set_bit(HIF_FIRST, &gh->gh_iflags);
497                 set_bit(GLF_LOCK, &gl->gl_flags);
498         } else {
499                 struct gfs2_holder *next_gh;
500                 if (gh->gh_state == LM_ST_EXCLUSIVE)
501                         return 1;
502                 next_gh = list_entry(gl->gl_holders.next, struct gfs2_holder,
503                                      gh_list);
504                 if (next_gh->gh_state == LM_ST_EXCLUSIVE)
505                          return 1;
506         }
507
508         list_move_tail(&gh->gh_list, &gl->gl_holders);
509         gh->gh_error = 0;
510         set_bit(HIF_HOLDER, &gh->gh_iflags);
511
512         gfs2_holder_wake(gh);
513
514         return 0;
515 }
516
517 /**
518  * rq_demote - process a demote request in the queue
519  * @gh: the glock holder
520  *
521  * Returns: 1 if the queue is blocked
522  */
523
524 static int rq_demote(struct gfs2_glock *gl)
525 {
526         if (!list_empty(&gl->gl_holders))
527                 return 1;
528
529         if (gl->gl_state == gl->gl_demote_state ||
530             gl->gl_state == LM_ST_UNLOCKED) {
531                 clear_bit(GLF_DEMOTE, &gl->gl_flags);
532                 return 0;
533         }
534         set_bit(GLF_LOCK, &gl->gl_flags);
535         spin_unlock(&gl->gl_spin);
536         if (gl->gl_demote_state == LM_ST_UNLOCKED ||
537             gl->gl_state != LM_ST_EXCLUSIVE)
538                 gfs2_glock_drop_th(gl);
539         else
540                 gfs2_glock_xmote_th(gl, NULL);
541         spin_lock(&gl->gl_spin);
542
543         return 0;
544 }
545
546 /**
547  * run_queue - process holder structures on a glock
548  * @gl: the glock
549  *
550  */
551 static void run_queue(struct gfs2_glock *gl)
552 {
553         struct gfs2_holder *gh;
554         int blocked = 1;
555
556         for (;;) {
557                 if (test_bit(GLF_LOCK, &gl->gl_flags))
558                         break;
559
560                 if (!list_empty(&gl->gl_waiters1)) {
561                         gh = list_entry(gl->gl_waiters1.next,
562                                         struct gfs2_holder, gh_list);
563
564                         if (test_bit(HIF_MUTEX, &gh->gh_iflags))
565                                 blocked = rq_mutex(gh);
566                         else
567                                 gfs2_assert_warn(gl->gl_sbd, 0);
568
569                 } else if (test_bit(GLF_DEMOTE, &gl->gl_flags)) {
570                         blocked = rq_demote(gl);
571                 } else if (!list_empty(&gl->gl_waiters3)) {
572                         gh = list_entry(gl->gl_waiters3.next,
573                                         struct gfs2_holder, gh_list);
574
575                         if (test_bit(HIF_PROMOTE, &gh->gh_iflags))
576                                 blocked = rq_promote(gh);
577                         else
578                                 gfs2_assert_warn(gl->gl_sbd, 0);
579
580                 } else
581                         break;
582
583                 if (blocked)
584                         break;
585         }
586 }
587
588 /**
589  * gfs2_glmutex_lock - acquire a local lock on a glock
590  * @gl: the glock
591  *
592  * Gives caller exclusive access to manipulate a glock structure.
593  */
594
595 static void gfs2_glmutex_lock(struct gfs2_glock *gl)
596 {
597         struct gfs2_holder gh;
598
599         gfs2_holder_init(gl, 0, 0, &gh);
600         set_bit(HIF_MUTEX, &gh.gh_iflags);
601         if (test_and_set_bit(HIF_WAIT, &gh.gh_iflags))
602                 BUG();
603
604         spin_lock(&gl->gl_spin);
605         if (test_and_set_bit(GLF_LOCK, &gl->gl_flags)) {
606                 list_add_tail(&gh.gh_list, &gl->gl_waiters1);
607         } else {
608                 gl->gl_owner_pid = current->pid;
609                 gl->gl_ip = (unsigned long)__builtin_return_address(0);
610                 clear_bit(HIF_WAIT, &gh.gh_iflags);
611                 smp_mb();
612                 wake_up_bit(&gh.gh_iflags, HIF_WAIT);
613         }
614         spin_unlock(&gl->gl_spin);
615
616         wait_on_holder(&gh);
617         gfs2_holder_uninit(&gh);
618 }
619
620 /**
621  * gfs2_glmutex_trylock - try to acquire a local lock on a glock
622  * @gl: the glock
623  *
624  * Returns: 1 if the glock is acquired
625  */
626
627 static int gfs2_glmutex_trylock(struct gfs2_glock *gl)
628 {
629         int acquired = 1;
630
631         spin_lock(&gl->gl_spin);
632         if (test_and_set_bit(GLF_LOCK, &gl->gl_flags)) {
633                 acquired = 0;
634         } else {
635                 gl->gl_owner_pid = current->pid;
636                 gl->gl_ip = (unsigned long)__builtin_return_address(0);
637         }
638         spin_unlock(&gl->gl_spin);
639
640         return acquired;
641 }
642
643 /**
644  * gfs2_glmutex_unlock - release a local lock on a glock
645  * @gl: the glock
646  *
647  */
648
649 static void gfs2_glmutex_unlock(struct gfs2_glock *gl)
650 {
651         spin_lock(&gl->gl_spin);
652         clear_bit(GLF_LOCK, &gl->gl_flags);
653         gl->gl_owner_pid = 0;
654         gl->gl_ip = 0;
655         run_queue(gl);
656         BUG_ON(!spin_is_locked(&gl->gl_spin));
657         spin_unlock(&gl->gl_spin);
658 }
659
660 /**
661  * handle_callback - process a demote request
662  * @gl: the glock
663  * @state: the state the caller wants us to change to
664  *
665  * There are only two requests that we are going to see in actual
666  * practise: LM_ST_SHARED and LM_ST_UNLOCKED
667  */
668
669 static void handle_callback(struct gfs2_glock *gl, unsigned int state)
670 {
671         spin_lock(&gl->gl_spin);
672         if (test_and_set_bit(GLF_DEMOTE, &gl->gl_flags) == 0) {
673                 gl->gl_demote_state = state;
674                 gl->gl_demote_time = jiffies;
675         } else if (gl->gl_demote_state != LM_ST_UNLOCKED) {
676                 gl->gl_demote_state = state;
677         }
678         spin_unlock(&gl->gl_spin);
679 }
680
681 /**
682  * state_change - record that the glock is now in a different state
683  * @gl: the glock
684  * @new_state the new state
685  *
686  */
687
688 static void state_change(struct gfs2_glock *gl, unsigned int new_state)
689 {
690         int held1, held2;
691
692         held1 = (gl->gl_state != LM_ST_UNLOCKED);
693         held2 = (new_state != LM_ST_UNLOCKED);
694
695         if (held1 != held2) {
696                 if (held2)
697                         gfs2_glock_hold(gl);
698                 else
699                         gfs2_glock_put(gl);
700         }
701
702         gl->gl_state = new_state;
703 }
704
705 /**
706  * xmote_bh - Called after the lock module is done acquiring a lock
707  * @gl: The glock in question
708  * @ret: the int returned from the lock module
709  *
710  */
711
712 static void xmote_bh(struct gfs2_glock *gl, unsigned int ret)
713 {
714         struct gfs2_sbd *sdp = gl->gl_sbd;
715         const struct gfs2_glock_operations *glops = gl->gl_ops;
716         struct gfs2_holder *gh = gl->gl_req_gh;
717         int prev_state = gl->gl_state;
718         int op_done = 1;
719
720         gfs2_assert_warn(sdp, test_bit(GLF_LOCK, &gl->gl_flags));
721         gfs2_assert_warn(sdp, list_empty(&gl->gl_holders));
722         gfs2_assert_warn(sdp, !(ret & LM_OUT_ASYNC));
723
724         state_change(gl, ret & LM_OUT_ST_MASK);
725
726         if (prev_state != LM_ST_UNLOCKED && !(ret & LM_OUT_CACHEABLE)) {
727                 if (glops->go_inval)
728                         glops->go_inval(gl, DIO_METADATA);
729         } else if (gl->gl_state == LM_ST_DEFERRED) {
730                 /* We might not want to do this here.
731                    Look at moving to the inode glops. */
732                 if (glops->go_inval)
733                         glops->go_inval(gl, 0);
734         }
735
736         /*  Deal with each possible exit condition  */
737
738         if (!gh) {
739                 gl->gl_stamp = jiffies;
740                 if (ret & LM_OUT_CANCELED)
741                         op_done = 0;
742                 else
743                         clear_bit(GLF_DEMOTE, &gl->gl_flags);
744         } else {
745                 spin_lock(&gl->gl_spin);
746                 list_del_init(&gh->gh_list);
747                 gh->gh_error = -EIO;
748                 if (unlikely(test_bit(SDF_SHUTDOWN, &sdp->sd_flags))) 
749                         goto out;
750                 gh->gh_error = GLR_CANCELED;
751                 if (ret & LM_OUT_CANCELED) 
752                         goto out;
753                 if (relaxed_state_ok(gl->gl_state, gh->gh_state, gh->gh_flags)) {
754                         list_add_tail(&gh->gh_list, &gl->gl_holders);
755                         gh->gh_error = 0;
756                         set_bit(HIF_HOLDER, &gh->gh_iflags);
757                         set_bit(HIF_FIRST, &gh->gh_iflags);
758                         op_done = 0;
759                         goto out;
760                 }
761                 gh->gh_error = GLR_TRYFAILED;
762                 if (gh->gh_flags & (LM_FLAG_TRY | LM_FLAG_TRY_1CB))
763                         goto out;
764                 gh->gh_error = -EINVAL;
765                 if (gfs2_assert_withdraw(sdp, 0) == -1)
766                         fs_err(sdp, "ret = 0x%.8X\n", ret);
767 out:
768                 spin_unlock(&gl->gl_spin);
769         }
770
771         if (glops->go_xmote_bh)
772                 glops->go_xmote_bh(gl);
773
774         if (op_done) {
775                 spin_lock(&gl->gl_spin);
776                 gl->gl_req_gh = NULL;
777                 gl->gl_req_bh = NULL;
778                 clear_bit(GLF_LOCK, &gl->gl_flags);
779                 run_queue(gl);
780                 spin_unlock(&gl->gl_spin);
781         }
782
783         gfs2_glock_put(gl);
784
785         if (gh)
786                 gfs2_holder_wake(gh);
787 }
788
789 /**
790  * gfs2_glock_xmote_th - Call into the lock module to acquire or change a glock
791  * @gl: The glock in question
792  * @state: the requested state
793  * @flags: modifier flags to the lock call
794  *
795  */
796
797 void gfs2_glock_xmote_th(struct gfs2_glock *gl, struct gfs2_holder *gh)
798 {
799         struct gfs2_sbd *sdp = gl->gl_sbd;
800         int flags = gh ? gh->gh_flags : 0;
801         unsigned state = gh ? gh->gh_state : gl->gl_demote_state;
802         const struct gfs2_glock_operations *glops = gl->gl_ops;
803         int lck_flags = flags & (LM_FLAG_TRY | LM_FLAG_TRY_1CB |
804                                  LM_FLAG_NOEXP | LM_FLAG_ANY |
805                                  LM_FLAG_PRIORITY);
806         unsigned int lck_ret;
807
808         if (glops->go_xmote_th)
809                 glops->go_xmote_th(gl);
810
811         gfs2_assert_warn(sdp, test_bit(GLF_LOCK, &gl->gl_flags));
812         gfs2_assert_warn(sdp, list_empty(&gl->gl_holders));
813         gfs2_assert_warn(sdp, state != LM_ST_UNLOCKED);
814         gfs2_assert_warn(sdp, state != gl->gl_state);
815
816         gfs2_glock_hold(gl);
817         gl->gl_req_bh = xmote_bh;
818
819         lck_ret = gfs2_lm_lock(sdp, gl->gl_lock, gl->gl_state, state, lck_flags);
820
821         if (gfs2_assert_withdraw(sdp, !(lck_ret & LM_OUT_ERROR)))
822                 return;
823
824         if (lck_ret & LM_OUT_ASYNC)
825                 gfs2_assert_warn(sdp, lck_ret == LM_OUT_ASYNC);
826         else
827                 xmote_bh(gl, lck_ret);
828 }
829
830 /**
831  * drop_bh - Called after a lock module unlock completes
832  * @gl: the glock
833  * @ret: the return status
834  *
835  * Doesn't wake up the process waiting on the struct gfs2_holder (if any)
836  * Doesn't drop the reference on the glock the top half took out
837  *
838  */
839
840 static void drop_bh(struct gfs2_glock *gl, unsigned int ret)
841 {
842         struct gfs2_sbd *sdp = gl->gl_sbd;
843         const struct gfs2_glock_operations *glops = gl->gl_ops;
844         struct gfs2_holder *gh = gl->gl_req_gh;
845
846         gfs2_assert_warn(sdp, test_bit(GLF_LOCK, &gl->gl_flags));
847         gfs2_assert_warn(sdp, list_empty(&gl->gl_holders));
848         gfs2_assert_warn(sdp, !ret);
849
850         state_change(gl, LM_ST_UNLOCKED);
851         clear_bit(GLF_DEMOTE, &gl->gl_flags);
852
853         if (glops->go_inval)
854                 glops->go_inval(gl, DIO_METADATA);
855
856         if (gh) {
857                 spin_lock(&gl->gl_spin);
858                 list_del_init(&gh->gh_list);
859                 gh->gh_error = 0;
860                 spin_unlock(&gl->gl_spin);
861         }
862
863         spin_lock(&gl->gl_spin);
864         gl->gl_req_gh = NULL;
865         gl->gl_req_bh = NULL;
866         clear_bit(GLF_LOCK, &gl->gl_flags);
867         run_queue(gl);
868         spin_unlock(&gl->gl_spin);
869
870         gfs2_glock_put(gl);
871
872         if (gh)
873                 gfs2_holder_wake(gh);
874 }
875
876 /**
877  * gfs2_glock_drop_th - call into the lock module to unlock a lock
878  * @gl: the glock
879  *
880  */
881
882 static void gfs2_glock_drop_th(struct gfs2_glock *gl)
883 {
884         struct gfs2_sbd *sdp = gl->gl_sbd;
885         const struct gfs2_glock_operations *glops = gl->gl_ops;
886         unsigned int ret;
887
888         if (glops->go_drop_th)
889                 glops->go_drop_th(gl);
890
891         gfs2_assert_warn(sdp, test_bit(GLF_LOCK, &gl->gl_flags));
892         gfs2_assert_warn(sdp, list_empty(&gl->gl_holders));
893         gfs2_assert_warn(sdp, gl->gl_state != LM_ST_UNLOCKED);
894
895         gfs2_glock_hold(gl);
896         gl->gl_req_bh = drop_bh;
897
898         ret = gfs2_lm_unlock(sdp, gl->gl_lock, gl->gl_state);
899
900         if (gfs2_assert_withdraw(sdp, !(ret & LM_OUT_ERROR)))
901                 return;
902
903         if (!ret)
904                 drop_bh(gl, ret);
905         else
906                 gfs2_assert_warn(sdp, ret == LM_OUT_ASYNC);
907 }
908
909 /**
910  * do_cancels - cancel requests for locks stuck waiting on an expire flag
911  * @gh: the LM_FLAG_PRIORITY holder waiting to acquire the lock
912  *
913  * Don't cancel GL_NOCANCEL requests.
914  */
915
916 static void do_cancels(struct gfs2_holder *gh)
917 {
918         struct gfs2_glock *gl = gh->gh_gl;
919
920         spin_lock(&gl->gl_spin);
921
922         while (gl->gl_req_gh != gh &&
923                !test_bit(HIF_HOLDER, &gh->gh_iflags) &&
924                !list_empty(&gh->gh_list)) {
925                 if (gl->gl_req_bh && !(gl->gl_req_gh &&
926                                      (gl->gl_req_gh->gh_flags & GL_NOCANCEL))) {
927                         spin_unlock(&gl->gl_spin);
928                         gfs2_lm_cancel(gl->gl_sbd, gl->gl_lock);
929                         msleep(100);
930                         spin_lock(&gl->gl_spin);
931                 } else {
932                         spin_unlock(&gl->gl_spin);
933                         msleep(100);
934                         spin_lock(&gl->gl_spin);
935                 }
936         }
937
938         spin_unlock(&gl->gl_spin);
939 }
940
941 /**
942  * glock_wait_internal - wait on a glock acquisition
943  * @gh: the glock holder
944  *
945  * Returns: 0 on success
946  */
947
948 static int glock_wait_internal(struct gfs2_holder *gh)
949 {
950         struct gfs2_glock *gl = gh->gh_gl;
951         struct gfs2_sbd *sdp = gl->gl_sbd;
952         const struct gfs2_glock_operations *glops = gl->gl_ops;
953
954         if (test_bit(HIF_ABORTED, &gh->gh_iflags))
955                 return -EIO;
956
957         if (gh->gh_flags & (LM_FLAG_TRY | LM_FLAG_TRY_1CB)) {
958                 spin_lock(&gl->gl_spin);
959                 if (gl->gl_req_gh != gh &&
960                     !test_bit(HIF_HOLDER, &gh->gh_iflags) &&
961                     !list_empty(&gh->gh_list)) {
962                         list_del_init(&gh->gh_list);
963                         gh->gh_error = GLR_TRYFAILED;
964                         run_queue(gl);
965                         spin_unlock(&gl->gl_spin);
966                         return gh->gh_error;
967                 }
968                 spin_unlock(&gl->gl_spin);
969         }
970
971         if (gh->gh_flags & LM_FLAG_PRIORITY)
972                 do_cancels(gh);
973
974         wait_on_holder(gh);
975         if (gh->gh_error)
976                 return gh->gh_error;
977
978         gfs2_assert_withdraw(sdp, test_bit(HIF_HOLDER, &gh->gh_iflags));
979         gfs2_assert_withdraw(sdp, relaxed_state_ok(gl->gl_state, gh->gh_state,
980                                                    gh->gh_flags));
981
982         if (test_bit(HIF_FIRST, &gh->gh_iflags)) {
983                 gfs2_assert_warn(sdp, test_bit(GLF_LOCK, &gl->gl_flags));
984
985                 if (glops->go_lock) {
986                         gh->gh_error = glops->go_lock(gh);
987                         if (gh->gh_error) {
988                                 spin_lock(&gl->gl_spin);
989                                 list_del_init(&gh->gh_list);
990                                 spin_unlock(&gl->gl_spin);
991                         }
992                 }
993
994                 spin_lock(&gl->gl_spin);
995                 gl->gl_req_gh = NULL;
996                 gl->gl_req_bh = NULL;
997                 clear_bit(GLF_LOCK, &gl->gl_flags);
998                 run_queue(gl);
999                 spin_unlock(&gl->gl_spin);
1000         }
1001
1002         return gh->gh_error;
1003 }
1004
1005 static inline struct gfs2_holder *
1006 find_holder_by_owner(struct list_head *head, pid_t pid)
1007 {
1008         struct gfs2_holder *gh;
1009
1010         list_for_each_entry(gh, head, gh_list) {
1011                 if (gh->gh_owner_pid == pid)
1012                         return gh;
1013         }
1014
1015         return NULL;
1016 }
1017
1018 static void print_dbg(struct glock_iter *gi, const char *fmt, ...)
1019 {
1020         va_list args;
1021
1022         va_start(args, fmt);
1023         if (gi) {
1024                 vsprintf(gi->string, fmt, args);
1025                 seq_printf(gi->seq, gi->string);
1026         }
1027         else
1028                 vprintk(fmt, args);
1029         va_end(args);
1030 }
1031
1032 /**
1033  * add_to_queue - Add a holder to the wait queue (but look for recursion)
1034  * @gh: the holder structure to add
1035  *
1036  */
1037
1038 static void add_to_queue(struct gfs2_holder *gh)
1039 {
1040         struct gfs2_glock *gl = gh->gh_gl;
1041         struct gfs2_holder *existing;
1042
1043         BUG_ON(!gh->gh_owner_pid);
1044         if (test_and_set_bit(HIF_WAIT, &gh->gh_iflags))
1045                 BUG();
1046
1047         existing = find_holder_by_owner(&gl->gl_holders, gh->gh_owner_pid);
1048         if (existing) {
1049                 print_symbol(KERN_WARNING "original: %s\n", existing->gh_ip);
1050                 printk(KERN_INFO "pid : %d\n", existing->gh_owner_pid);
1051                 printk(KERN_INFO "lock type : %d lock state : %d\n",
1052                                 existing->gh_gl->gl_name.ln_type, existing->gh_gl->gl_state);
1053                 print_symbol(KERN_WARNING "new: %s\n", gh->gh_ip);
1054                 printk(KERN_INFO "pid : %d\n", gh->gh_owner_pid);
1055                 printk(KERN_INFO "lock type : %d lock state : %d\n",
1056                                 gl->gl_name.ln_type, gl->gl_state);
1057                 BUG();
1058         }
1059
1060         existing = find_holder_by_owner(&gl->gl_waiters3, gh->gh_owner_pid);
1061         if (existing) {
1062                 print_symbol(KERN_WARNING "original: %s\n", existing->gh_ip);
1063                 print_symbol(KERN_WARNING "new: %s\n", gh->gh_ip);
1064                 BUG();
1065         }
1066
1067         if (gh->gh_flags & LM_FLAG_PRIORITY)
1068                 list_add(&gh->gh_list, &gl->gl_waiters3);
1069         else
1070                 list_add_tail(&gh->gh_list, &gl->gl_waiters3);
1071 }
1072
1073 /**
1074  * gfs2_glock_nq - enqueue a struct gfs2_holder onto a glock (acquire a glock)
1075  * @gh: the holder structure
1076  *
1077  * if (gh->gh_flags & GL_ASYNC), this never returns an error
1078  *
1079  * Returns: 0, GLR_TRYFAILED, or errno on failure
1080  */
1081
1082 int gfs2_glock_nq(struct gfs2_holder *gh)
1083 {
1084         struct gfs2_glock *gl = gh->gh_gl;
1085         struct gfs2_sbd *sdp = gl->gl_sbd;
1086         int error = 0;
1087
1088 restart:
1089         if (unlikely(test_bit(SDF_SHUTDOWN, &sdp->sd_flags))) {
1090                 set_bit(HIF_ABORTED, &gh->gh_iflags);
1091                 return -EIO;
1092         }
1093
1094         set_bit(HIF_PROMOTE, &gh->gh_iflags);
1095
1096         spin_lock(&gl->gl_spin);
1097         add_to_queue(gh);
1098         run_queue(gl);
1099         spin_unlock(&gl->gl_spin);
1100
1101         if (!(gh->gh_flags & GL_ASYNC)) {
1102                 error = glock_wait_internal(gh);
1103                 if (error == GLR_CANCELED) {
1104                         msleep(100);
1105                         goto restart;
1106                 }
1107         }
1108
1109         return error;
1110 }
1111
1112 /**
1113  * gfs2_glock_poll - poll to see if an async request has been completed
1114  * @gh: the holder
1115  *
1116  * Returns: 1 if the request is ready to be gfs2_glock_wait()ed on
1117  */
1118
1119 int gfs2_glock_poll(struct gfs2_holder *gh)
1120 {
1121         struct gfs2_glock *gl = gh->gh_gl;
1122         int ready = 0;
1123
1124         spin_lock(&gl->gl_spin);
1125
1126         if (test_bit(HIF_HOLDER, &gh->gh_iflags))
1127                 ready = 1;
1128         else if (list_empty(&gh->gh_list)) {
1129                 if (gh->gh_error == GLR_CANCELED) {
1130                         spin_unlock(&gl->gl_spin);
1131                         msleep(100);
1132                         if (gfs2_glock_nq(gh))
1133                                 return 1;
1134                         return 0;
1135                 } else
1136                         ready = 1;
1137         }
1138
1139         spin_unlock(&gl->gl_spin);
1140
1141         return ready;
1142 }
1143
1144 /**
1145  * gfs2_glock_wait - wait for a lock acquisition that ended in a GLR_ASYNC
1146  * @gh: the holder structure
1147  *
1148  * Returns: 0, GLR_TRYFAILED, or errno on failure
1149  */
1150
1151 int gfs2_glock_wait(struct gfs2_holder *gh)
1152 {
1153         int error;
1154
1155         error = glock_wait_internal(gh);
1156         if (error == GLR_CANCELED) {
1157                 msleep(100);
1158                 gh->gh_flags &= ~GL_ASYNC;
1159                 error = gfs2_glock_nq(gh);
1160         }
1161
1162         return error;
1163 }
1164
1165 /**
1166  * gfs2_glock_dq - dequeue a struct gfs2_holder from a glock (release a glock)
1167  * @gh: the glock holder
1168  *
1169  */
1170
1171 void gfs2_glock_dq(struct gfs2_holder *gh)
1172 {
1173         struct gfs2_glock *gl = gh->gh_gl;
1174         const struct gfs2_glock_operations *glops = gl->gl_ops;
1175
1176         if (gh->gh_flags & GL_NOCACHE)
1177                 handle_callback(gl, LM_ST_UNLOCKED);
1178
1179         gfs2_glmutex_lock(gl);
1180
1181         spin_lock(&gl->gl_spin);
1182         list_del_init(&gh->gh_list);
1183
1184         if (list_empty(&gl->gl_holders)) {
1185                 spin_unlock(&gl->gl_spin);
1186
1187                 if (glops->go_unlock)
1188                         glops->go_unlock(gh);
1189
1190                 spin_lock(&gl->gl_spin);
1191                 gl->gl_stamp = jiffies;
1192         }
1193
1194         clear_bit(GLF_LOCK, &gl->gl_flags);
1195         run_queue(gl);
1196         spin_unlock(&gl->gl_spin);
1197 }
1198
1199 /**
1200  * gfs2_glock_dq_uninit - dequeue a holder from a glock and initialize it
1201  * @gh: the holder structure
1202  *
1203  */
1204
1205 void gfs2_glock_dq_uninit(struct gfs2_holder *gh)
1206 {
1207         gfs2_glock_dq(gh);
1208         gfs2_holder_uninit(gh);
1209 }
1210
1211 /**
1212  * gfs2_glock_nq_num - acquire a glock based on lock number
1213  * @sdp: the filesystem
1214  * @number: the lock number
1215  * @glops: the glock operations for the type of glock
1216  * @state: the state to acquire the glock in
1217  * @flags: modifier flags for the aquisition
1218  * @gh: the struct gfs2_holder
1219  *
1220  * Returns: errno
1221  */
1222
1223 int gfs2_glock_nq_num(struct gfs2_sbd *sdp, u64 number,
1224                       const struct gfs2_glock_operations *glops,
1225                       unsigned int state, int flags, struct gfs2_holder *gh)
1226 {
1227         struct gfs2_glock *gl;
1228         int error;
1229
1230         error = gfs2_glock_get(sdp, number, glops, CREATE, &gl);
1231         if (!error) {
1232                 error = gfs2_glock_nq_init(gl, state, flags, gh);
1233                 gfs2_glock_put(gl);
1234         }
1235
1236         return error;
1237 }
1238
1239 /**
1240  * glock_compare - Compare two struct gfs2_glock structures for sorting
1241  * @arg_a: the first structure
1242  * @arg_b: the second structure
1243  *
1244  */
1245
1246 static int glock_compare(const void *arg_a, const void *arg_b)
1247 {
1248         const struct gfs2_holder *gh_a = *(const struct gfs2_holder **)arg_a;
1249         const struct gfs2_holder *gh_b = *(const struct gfs2_holder **)arg_b;
1250         const struct lm_lockname *a = &gh_a->gh_gl->gl_name;
1251         const struct lm_lockname *b = &gh_b->gh_gl->gl_name;
1252
1253         if (a->ln_number > b->ln_number)
1254                 return 1;
1255         if (a->ln_number < b->ln_number)
1256                 return -1;
1257         BUG_ON(gh_a->gh_gl->gl_ops->go_type == gh_b->gh_gl->gl_ops->go_type);
1258         return 0;
1259 }
1260
1261 /**
1262  * nq_m_sync - synchonously acquire more than one glock in deadlock free order
1263  * @num_gh: the number of structures
1264  * @ghs: an array of struct gfs2_holder structures
1265  *
1266  * Returns: 0 on success (all glocks acquired),
1267  *          errno on failure (no glocks acquired)
1268  */
1269
1270 static int nq_m_sync(unsigned int num_gh, struct gfs2_holder *ghs,
1271                      struct gfs2_holder **p)
1272 {
1273         unsigned int x;
1274         int error = 0;
1275
1276         for (x = 0; x < num_gh; x++)
1277                 p[x] = &ghs[x];
1278
1279         sort(p, num_gh, sizeof(struct gfs2_holder *), glock_compare, NULL);
1280
1281         for (x = 0; x < num_gh; x++) {
1282                 p[x]->gh_flags &= ~(LM_FLAG_TRY | GL_ASYNC);
1283
1284                 error = gfs2_glock_nq(p[x]);
1285                 if (error) {
1286                         while (x--)
1287                                 gfs2_glock_dq(p[x]);
1288                         break;
1289                 }
1290         }
1291
1292         return error;
1293 }
1294
1295 /**
1296  * gfs2_glock_nq_m - acquire multiple glocks
1297  * @num_gh: the number of structures
1298  * @ghs: an array of struct gfs2_holder structures
1299  *
1300  * Figure out how big an impact this function has.  Either:
1301  * 1) Replace this code with code that calls gfs2_glock_prefetch()
1302  * 2) Forget async stuff and just call nq_m_sync()
1303  * 3) Leave it like it is
1304  *
1305  * Returns: 0 on success (all glocks acquired),
1306  *          errno on failure (no glocks acquired)
1307  */
1308
1309 int gfs2_glock_nq_m(unsigned int num_gh, struct gfs2_holder *ghs)
1310 {
1311         int *e;
1312         unsigned int x;
1313         int borked = 0, serious = 0;
1314         int error = 0;
1315
1316         if (!num_gh)
1317                 return 0;
1318
1319         if (num_gh == 1) {
1320                 ghs->gh_flags &= ~(LM_FLAG_TRY | GL_ASYNC);
1321                 return gfs2_glock_nq(ghs);
1322         }
1323
1324         e = kcalloc(num_gh, sizeof(struct gfs2_holder *), GFP_KERNEL);
1325         if (!e)
1326                 return -ENOMEM;
1327
1328         for (x = 0; x < num_gh; x++) {
1329                 ghs[x].gh_flags |= LM_FLAG_TRY | GL_ASYNC;
1330                 error = gfs2_glock_nq(&ghs[x]);
1331                 if (error) {
1332                         borked = 1;
1333                         serious = error;
1334                         num_gh = x;
1335                         break;
1336                 }
1337         }
1338
1339         for (x = 0; x < num_gh; x++) {
1340                 error = e[x] = glock_wait_internal(&ghs[x]);
1341                 if (error) {
1342                         borked = 1;
1343                         if (error != GLR_TRYFAILED && error != GLR_CANCELED)
1344                                 serious = error;
1345                 }
1346         }
1347
1348         if (!borked) {
1349                 kfree(e);
1350                 return 0;
1351         }
1352
1353         for (x = 0; x < num_gh; x++)
1354                 if (!e[x])
1355                         gfs2_glock_dq(&ghs[x]);
1356
1357         if (serious)
1358                 error = serious;
1359         else {
1360                 for (x = 0; x < num_gh; x++)
1361                         gfs2_holder_reinit(ghs[x].gh_state, ghs[x].gh_flags,
1362                                           &ghs[x]);
1363                 error = nq_m_sync(num_gh, ghs, (struct gfs2_holder **)e);
1364         }
1365
1366         kfree(e);
1367
1368         return error;
1369 }
1370
1371 /**
1372  * gfs2_glock_dq_m - release multiple glocks
1373  * @num_gh: the number of structures
1374  * @ghs: an array of struct gfs2_holder structures
1375  *
1376  */
1377
1378 void gfs2_glock_dq_m(unsigned int num_gh, struct gfs2_holder *ghs)
1379 {
1380         unsigned int x;
1381
1382         for (x = 0; x < num_gh; x++)
1383                 gfs2_glock_dq(&ghs[x]);
1384 }
1385
1386 /**
1387  * gfs2_glock_dq_uninit_m - release multiple glocks
1388  * @num_gh: the number of structures
1389  * @ghs: an array of struct gfs2_holder structures
1390  *
1391  */
1392
1393 void gfs2_glock_dq_uninit_m(unsigned int num_gh, struct gfs2_holder *ghs)
1394 {
1395         unsigned int x;
1396
1397         for (x = 0; x < num_gh; x++)
1398                 gfs2_glock_dq_uninit(&ghs[x]);
1399 }
1400
1401 /**
1402  * gfs2_lvb_hold - attach a LVB from a glock
1403  * @gl: The glock in question
1404  *
1405  */
1406
1407 int gfs2_lvb_hold(struct gfs2_glock *gl)
1408 {
1409         int error;
1410
1411         gfs2_glmutex_lock(gl);
1412
1413         if (!atomic_read(&gl->gl_lvb_count)) {
1414                 error = gfs2_lm_hold_lvb(gl->gl_sbd, gl->gl_lock, &gl->gl_lvb);
1415                 if (error) {
1416                         gfs2_glmutex_unlock(gl);
1417                         return error;
1418                 }
1419                 gfs2_glock_hold(gl);
1420         }
1421         atomic_inc(&gl->gl_lvb_count);
1422
1423         gfs2_glmutex_unlock(gl);
1424
1425         return 0;
1426 }
1427
1428 /**
1429  * gfs2_lvb_unhold - detach a LVB from a glock
1430  * @gl: The glock in question
1431  *
1432  */
1433
1434 void gfs2_lvb_unhold(struct gfs2_glock *gl)
1435 {
1436         gfs2_glock_hold(gl);
1437         gfs2_glmutex_lock(gl);
1438
1439         gfs2_assert(gl->gl_sbd, atomic_read(&gl->gl_lvb_count) > 0);
1440         if (atomic_dec_and_test(&gl->gl_lvb_count)) {
1441                 gfs2_lm_unhold_lvb(gl->gl_sbd, gl->gl_lock, gl->gl_lvb);
1442                 gl->gl_lvb = NULL;
1443                 gfs2_glock_put(gl);
1444         }
1445
1446         gfs2_glmutex_unlock(gl);
1447         gfs2_glock_put(gl);
1448 }
1449
1450 static void blocking_cb(struct gfs2_sbd *sdp, struct lm_lockname *name,
1451                         unsigned int state)
1452 {
1453         struct gfs2_glock *gl;
1454
1455         gl = gfs2_glock_find(sdp, name);
1456         if (!gl)
1457                 return;
1458
1459         handle_callback(gl, state);
1460
1461         spin_lock(&gl->gl_spin);
1462         run_queue(gl);
1463         spin_unlock(&gl->gl_spin);
1464
1465         gfs2_glock_put(gl);
1466 }
1467
1468 /**
1469  * gfs2_glock_cb - Callback used by locking module
1470  * @sdp: Pointer to the superblock
1471  * @type: Type of callback
1472  * @data: Type dependent data pointer
1473  *
1474  * Called by the locking module when it wants to tell us something.
1475  * Either we need to drop a lock, one of our ASYNC requests completed, or
1476  * a journal from another client needs to be recovered.
1477  */
1478
1479 void gfs2_glock_cb(void *cb_data, unsigned int type, void *data)
1480 {
1481         struct gfs2_sbd *sdp = cb_data;
1482
1483         switch (type) {
1484         case LM_CB_NEED_E:
1485                 blocking_cb(sdp, data, LM_ST_UNLOCKED);
1486                 return;
1487
1488         case LM_CB_NEED_D:
1489                 blocking_cb(sdp, data, LM_ST_DEFERRED);
1490                 return;
1491
1492         case LM_CB_NEED_S:
1493                 blocking_cb(sdp, data, LM_ST_SHARED);
1494                 return;
1495
1496         case LM_CB_ASYNC: {
1497                 struct lm_async_cb *async = data;
1498                 struct gfs2_glock *gl;
1499
1500                 down_read(&gfs2_umount_flush_sem);
1501                 gl = gfs2_glock_find(sdp, &async->lc_name);
1502                 if (gfs2_assert_warn(sdp, gl))
1503                         return;
1504                 if (!gfs2_assert_warn(sdp, gl->gl_req_bh))
1505                         gl->gl_req_bh(gl, async->lc_ret);
1506                 gfs2_glock_put(gl);
1507                 up_read(&gfs2_umount_flush_sem);
1508                 return;
1509         }
1510
1511         case LM_CB_NEED_RECOVERY:
1512                 gfs2_jdesc_make_dirty(sdp, *(unsigned int *)data);
1513                 if (sdp->sd_recoverd_process)
1514                         wake_up_process(sdp->sd_recoverd_process);
1515                 return;
1516
1517         case LM_CB_DROPLOCKS:
1518                 gfs2_gl_hash_clear(sdp, NO_WAIT);
1519                 gfs2_quota_scan(sdp);
1520                 return;
1521
1522         default:
1523                 gfs2_assert_warn(sdp, 0);
1524                 return;
1525         }
1526 }
1527
1528 /**
1529  * demote_ok - Check to see if it's ok to unlock a glock
1530  * @gl: the glock
1531  *
1532  * Returns: 1 if it's ok
1533  */
1534
1535 static int demote_ok(struct gfs2_glock *gl)
1536 {
1537         const struct gfs2_glock_operations *glops = gl->gl_ops;
1538         int demote = 1;
1539
1540         if (test_bit(GLF_STICKY, &gl->gl_flags))
1541                 demote = 0;
1542         else if (glops->go_demote_ok)
1543                 demote = glops->go_demote_ok(gl);
1544
1545         return demote;
1546 }
1547
1548 /**
1549  * gfs2_glock_schedule_for_reclaim - Add a glock to the reclaim list
1550  * @gl: the glock
1551  *
1552  */
1553
1554 void gfs2_glock_schedule_for_reclaim(struct gfs2_glock *gl)
1555 {
1556         struct gfs2_sbd *sdp = gl->gl_sbd;
1557
1558         spin_lock(&sdp->sd_reclaim_lock);
1559         if (list_empty(&gl->gl_reclaim)) {
1560                 gfs2_glock_hold(gl);
1561                 list_add(&gl->gl_reclaim, &sdp->sd_reclaim_list);
1562                 atomic_inc(&sdp->sd_reclaim_count);
1563         }
1564         spin_unlock(&sdp->sd_reclaim_lock);
1565
1566         wake_up(&sdp->sd_reclaim_wq);
1567 }
1568
1569 /**
1570  * gfs2_reclaim_glock - process the next glock on the filesystem's reclaim list
1571  * @sdp: the filesystem
1572  *
1573  * Called from gfs2_glockd() glock reclaim daemon, or when promoting a
1574  * different glock and we notice that there are a lot of glocks in the
1575  * reclaim list.
1576  *
1577  */
1578
1579 void gfs2_reclaim_glock(struct gfs2_sbd *sdp)
1580 {
1581         struct gfs2_glock *gl;
1582
1583         spin_lock(&sdp->sd_reclaim_lock);
1584         if (list_empty(&sdp->sd_reclaim_list)) {
1585                 spin_unlock(&sdp->sd_reclaim_lock);
1586                 return;
1587         }
1588         gl = list_entry(sdp->sd_reclaim_list.next,
1589                         struct gfs2_glock, gl_reclaim);
1590         list_del_init(&gl->gl_reclaim);
1591         spin_unlock(&sdp->sd_reclaim_lock);
1592
1593         atomic_dec(&sdp->sd_reclaim_count);
1594         atomic_inc(&sdp->sd_reclaimed);
1595
1596         if (gfs2_glmutex_trylock(gl)) {
1597                 if (list_empty(&gl->gl_holders) &&
1598                     gl->gl_state != LM_ST_UNLOCKED && demote_ok(gl))
1599                         handle_callback(gl, LM_ST_UNLOCKED);
1600                 gfs2_glmutex_unlock(gl);
1601         }
1602
1603         gfs2_glock_put(gl);
1604 }
1605
1606 /**
1607  * examine_bucket - Call a function for glock in a hash bucket
1608  * @examiner: the function
1609  * @sdp: the filesystem
1610  * @bucket: the bucket
1611  *
1612  * Returns: 1 if the bucket has entries
1613  */
1614
1615 static int examine_bucket(glock_examiner examiner, struct gfs2_sbd *sdp,
1616                           unsigned int hash)
1617 {
1618         struct gfs2_glock *gl, *prev = NULL;
1619         int has_entries = 0;
1620         struct hlist_head *head = &gl_hash_table[hash].hb_list;
1621
1622         read_lock(gl_lock_addr(hash));
1623         /* Can't use hlist_for_each_entry - don't want prefetch here */
1624         if (hlist_empty(head))
1625                 goto out;
1626         gl = list_entry(head->first, struct gfs2_glock, gl_list);
1627         while(1) {
1628                 if (gl->gl_sbd == sdp) {
1629                         gfs2_glock_hold(gl);
1630                         read_unlock(gl_lock_addr(hash));
1631                         if (prev)
1632                                 gfs2_glock_put(prev);
1633                         prev = gl;
1634                         examiner(gl);
1635                         has_entries = 1;
1636                         read_lock(gl_lock_addr(hash));
1637                 }
1638                 if (gl->gl_list.next == NULL)
1639                         break;
1640                 gl = list_entry(gl->gl_list.next, struct gfs2_glock, gl_list);
1641         }
1642 out:
1643         read_unlock(gl_lock_addr(hash));
1644         if (prev)
1645                 gfs2_glock_put(prev);
1646         return has_entries;
1647 }
1648
1649 /**
1650  * scan_glock - look at a glock and see if we can reclaim it
1651  * @gl: the glock to look at
1652  *
1653  */
1654
1655 static void scan_glock(struct gfs2_glock *gl)
1656 {
1657         if (gl->gl_ops == &gfs2_inode_glops && gl->gl_object)
1658                 return;
1659
1660         if (gfs2_glmutex_trylock(gl)) {
1661                 if (list_empty(&gl->gl_holders) &&
1662                     gl->gl_state != LM_ST_UNLOCKED && demote_ok(gl))
1663                         goto out_schedule;
1664                 gfs2_glmutex_unlock(gl);
1665         }
1666         return;
1667
1668 out_schedule:
1669         gfs2_glmutex_unlock(gl);
1670         gfs2_glock_schedule_for_reclaim(gl);
1671 }
1672
1673 /**
1674  * gfs2_scand_internal - Look for glocks and inodes to toss from memory
1675  * @sdp: the filesystem
1676  *
1677  */
1678
1679 void gfs2_scand_internal(struct gfs2_sbd *sdp)
1680 {
1681         unsigned int x;
1682
1683         for (x = 0; x < GFS2_GL_HASH_SIZE; x++)
1684                 examine_bucket(scan_glock, sdp, x);
1685 }
1686
1687 /**
1688  * clear_glock - look at a glock and see if we can free it from glock cache
1689  * @gl: the glock to look at
1690  *
1691  */
1692
1693 static void clear_glock(struct gfs2_glock *gl)
1694 {
1695         struct gfs2_sbd *sdp = gl->gl_sbd;
1696         int released;
1697
1698         spin_lock(&sdp->sd_reclaim_lock);
1699         if (!list_empty(&gl->gl_reclaim)) {
1700                 list_del_init(&gl->gl_reclaim);
1701                 atomic_dec(&sdp->sd_reclaim_count);
1702                 spin_unlock(&sdp->sd_reclaim_lock);
1703                 released = gfs2_glock_put(gl);
1704                 gfs2_assert(sdp, !released);
1705         } else {
1706                 spin_unlock(&sdp->sd_reclaim_lock);
1707         }
1708
1709         if (gfs2_glmutex_trylock(gl)) {
1710                 if (list_empty(&gl->gl_holders) &&
1711                     gl->gl_state != LM_ST_UNLOCKED)
1712                         handle_callback(gl, LM_ST_UNLOCKED);
1713                 gfs2_glmutex_unlock(gl);
1714         }
1715 }
1716
1717 /**
1718  * gfs2_gl_hash_clear - Empty out the glock hash table
1719  * @sdp: the filesystem
1720  * @wait: wait until it's all gone
1721  *
1722  * Called when unmounting the filesystem, or when inter-node lock manager
1723  * requests DROPLOCKS because it is running out of capacity.
1724  */
1725
1726 void gfs2_gl_hash_clear(struct gfs2_sbd *sdp, int wait)
1727 {
1728         unsigned long t;
1729         unsigned int x;
1730         int cont;
1731
1732         t = jiffies;
1733
1734         for (;;) {
1735                 cont = 0;
1736                 for (x = 0; x < GFS2_GL_HASH_SIZE; x++) {
1737                         if (examine_bucket(clear_glock, sdp, x))
1738                                 cont = 1;
1739                 }
1740
1741                 if (!wait || !cont)
1742                         break;
1743
1744                 if (time_after_eq(jiffies,
1745                                   t + gfs2_tune_get(sdp, gt_stall_secs) * HZ)) {
1746                         fs_warn(sdp, "Unmount seems to be stalled. "
1747                                      "Dumping lock state...\n");
1748                         gfs2_dump_lockstate(sdp);
1749                         t = jiffies;
1750                 }
1751
1752                 down_write(&gfs2_umount_flush_sem);
1753                 invalidate_inodes(sdp->sd_vfs);
1754                 up_write(&gfs2_umount_flush_sem);
1755                 msleep(10);
1756         }
1757 }
1758
1759 /*
1760  *  Diagnostic routines to help debug distributed deadlock
1761  */
1762
1763 static void gfs2_print_symbol(struct glock_iter *gi, const char *fmt,
1764                               unsigned long address)
1765 {
1766         char buffer[KSYM_SYMBOL_LEN];
1767
1768         sprint_symbol(buffer, address);
1769         print_dbg(gi, fmt, buffer);
1770 }
1771
1772 /**
1773  * dump_holder - print information about a glock holder
1774  * @str: a string naming the type of holder
1775  * @gh: the glock holder
1776  *
1777  * Returns: 0 on success, -ENOBUFS when we run out of space
1778  */
1779
1780 static int dump_holder(struct glock_iter *gi, char *str,
1781                        struct gfs2_holder *gh)
1782 {
1783         unsigned int x;
1784         struct task_struct *gh_owner;
1785
1786         print_dbg(gi, "  %s\n", str);
1787         if (gh->gh_owner_pid) {
1788                 print_dbg(gi, "    owner = %ld ", (long)gh->gh_owner_pid);
1789                 gh_owner = find_task_by_pid(gh->gh_owner_pid);
1790                 if (gh_owner)
1791                         print_dbg(gi, "(%s)\n", gh_owner->comm);
1792                 else
1793                         print_dbg(gi, "(ended)\n");
1794         } else
1795                 print_dbg(gi, "    owner = -1\n");
1796         print_dbg(gi, "    gh_state = %u\n", gh->gh_state);
1797         print_dbg(gi, "    gh_flags =");
1798         for (x = 0; x < 32; x++)
1799                 if (gh->gh_flags & (1 << x))
1800                         print_dbg(gi, " %u", x);
1801         print_dbg(gi, " \n");
1802         print_dbg(gi, "    error = %d\n", gh->gh_error);
1803         print_dbg(gi, "    gh_iflags =");
1804         for (x = 0; x < 32; x++)
1805                 if (test_bit(x, &gh->gh_iflags))
1806                         print_dbg(gi, " %u", x);
1807         print_dbg(gi, " \n");
1808         gfs2_print_symbol(gi, "    initialized at: %s\n", gh->gh_ip);
1809
1810         return 0;
1811 }
1812
1813 /**
1814  * dump_inode - print information about an inode
1815  * @ip: the inode
1816  *
1817  * Returns: 0 on success, -ENOBUFS when we run out of space
1818  */
1819
1820 static int dump_inode(struct glock_iter *gi, struct gfs2_inode *ip)
1821 {
1822         unsigned int x;
1823
1824         print_dbg(gi, "  Inode:\n");
1825         print_dbg(gi, "    num = %llu/%llu\n",
1826                   (unsigned long long)ip->i_no_formal_ino,
1827                   (unsigned long long)ip->i_no_addr);
1828         print_dbg(gi, "    type = %u\n", IF2DT(ip->i_inode.i_mode));
1829         print_dbg(gi, "    i_flags =");
1830         for (x = 0; x < 32; x++)
1831                 if (test_bit(x, &ip->i_flags))
1832                         print_dbg(gi, " %u", x);
1833         print_dbg(gi, " \n");
1834         return 0;
1835 }
1836
1837 /**
1838  * dump_glock - print information about a glock
1839  * @gl: the glock
1840  * @count: where we are in the buffer
1841  *
1842  * Returns: 0 on success, -ENOBUFS when we run out of space
1843  */
1844
1845 static int dump_glock(struct glock_iter *gi, struct gfs2_glock *gl)
1846 {
1847         struct gfs2_holder *gh;
1848         unsigned int x;
1849         int error = -ENOBUFS;
1850         struct task_struct *gl_owner;
1851
1852         spin_lock(&gl->gl_spin);
1853
1854         print_dbg(gi, "Glock 0x%p (%u, %llu)\n", gl, gl->gl_name.ln_type,
1855                    (unsigned long long)gl->gl_name.ln_number);
1856         print_dbg(gi, "  gl_flags =");
1857         for (x = 0; x < 32; x++) {
1858                 if (test_bit(x, &gl->gl_flags))
1859                         print_dbg(gi, " %u", x);
1860         }
1861         if (!test_bit(GLF_LOCK, &gl->gl_flags))
1862                 print_dbg(gi, " (unlocked)");
1863         print_dbg(gi, " \n");
1864         print_dbg(gi, "  gl_ref = %d\n", atomic_read(&gl->gl_ref));
1865         print_dbg(gi, "  gl_state = %u\n", gl->gl_state);
1866         if (gl->gl_owner_pid) {
1867                 gl_owner = find_task_by_pid(gl->gl_owner_pid);
1868                 if (gl_owner)
1869                         print_dbg(gi, "  gl_owner = pid %d (%s)\n",
1870                                   gl->gl_owner_pid, gl_owner->comm);
1871                 else
1872                         print_dbg(gi, "  gl_owner = %d (ended)\n",
1873                                   gl->gl_owner_pid);
1874         } else
1875                 print_dbg(gi, "  gl_owner = -1\n");
1876         print_dbg(gi, "  gl_ip = %lu\n", gl->gl_ip);
1877         print_dbg(gi, "  req_gh = %s\n", (gl->gl_req_gh) ? "yes" : "no");
1878         print_dbg(gi, "  req_bh = %s\n", (gl->gl_req_bh) ? "yes" : "no");
1879         print_dbg(gi, "  lvb_count = %d\n", atomic_read(&gl->gl_lvb_count));
1880         print_dbg(gi, "  object = %s\n", (gl->gl_object) ? "yes" : "no");
1881         print_dbg(gi, "  le = %s\n",
1882                    (list_empty(&gl->gl_le.le_list)) ? "no" : "yes");
1883         print_dbg(gi, "  reclaim = %s\n",
1884                    (list_empty(&gl->gl_reclaim)) ? "no" : "yes");
1885         if (gl->gl_aspace)
1886                 print_dbg(gi, "  aspace = 0x%p nrpages = %lu\n", gl->gl_aspace,
1887                            gl->gl_aspace->i_mapping->nrpages);
1888         else
1889                 print_dbg(gi, "  aspace = no\n");
1890         print_dbg(gi, "  ail = %d\n", atomic_read(&gl->gl_ail_count));
1891         if (gl->gl_req_gh) {
1892                 error = dump_holder(gi, "Request", gl->gl_req_gh);
1893                 if (error)
1894                         goto out;
1895         }
1896         list_for_each_entry(gh, &gl->gl_holders, gh_list) {
1897                 error = dump_holder(gi, "Holder", gh);
1898                 if (error)
1899                         goto out;
1900         }
1901         list_for_each_entry(gh, &gl->gl_waiters1, gh_list) {
1902                 error = dump_holder(gi, "Waiter1", gh);
1903                 if (error)
1904                         goto out;
1905         }
1906         list_for_each_entry(gh, &gl->gl_waiters3, gh_list) {
1907                 error = dump_holder(gi, "Waiter3", gh);
1908                 if (error)
1909                         goto out;
1910         }
1911         if (test_bit(GLF_DEMOTE, &gl->gl_flags)) {
1912                 print_dbg(gi, "  Demotion req to state %u (%llu uS ago)\n",
1913                           gl->gl_demote_state, (unsigned long long)
1914                           (jiffies - gl->gl_demote_time)*(1000000/HZ));
1915         }
1916         if (gl->gl_ops == &gfs2_inode_glops && gl->gl_object) {
1917                 if (!test_bit(GLF_LOCK, &gl->gl_flags) &&
1918                         list_empty(&gl->gl_holders)) {
1919                         error = dump_inode(gi, gl->gl_object);
1920                         if (error)
1921                                 goto out;
1922                 } else {
1923                         error = -ENOBUFS;
1924                         print_dbg(gi, "  Inode: busy\n");
1925                 }
1926         }
1927
1928         error = 0;
1929
1930 out:
1931         spin_unlock(&gl->gl_spin);
1932         return error;
1933 }
1934
1935 /**
1936  * gfs2_dump_lockstate - print out the current lockstate
1937  * @sdp: the filesystem
1938  * @ub: the buffer to copy the information into
1939  *
1940  * If @ub is NULL, dump the lockstate to the console.
1941  *
1942  */
1943
1944 static int gfs2_dump_lockstate(struct gfs2_sbd *sdp)
1945 {
1946         struct gfs2_glock *gl;
1947         struct hlist_node *h;
1948         unsigned int x;
1949         int error = 0;
1950
1951         for (x = 0; x < GFS2_GL_HASH_SIZE; x++) {
1952
1953                 read_lock(gl_lock_addr(x));
1954
1955                 hlist_for_each_entry(gl, h, &gl_hash_table[x].hb_list, gl_list) {
1956                         if (gl->gl_sbd != sdp)
1957                                 continue;
1958
1959                         error = dump_glock(NULL, gl);
1960                         if (error)
1961                                 break;
1962                 }
1963
1964                 read_unlock(gl_lock_addr(x));
1965
1966                 if (error)
1967                         break;
1968         }
1969
1970
1971         return error;
1972 }
1973
1974 int __init gfs2_glock_init(void)
1975 {
1976         unsigned i;
1977         for(i = 0; i < GFS2_GL_HASH_SIZE; i++) {
1978                 INIT_HLIST_HEAD(&gl_hash_table[i].hb_list);
1979         }
1980 #ifdef GL_HASH_LOCK_SZ
1981         for(i = 0; i < GL_HASH_LOCK_SZ; i++) {
1982                 rwlock_init(&gl_hash_locks[i]);
1983         }
1984 #endif
1985         return 0;
1986 }
1987
1988 static int gfs2_glock_iter_next(struct glock_iter *gi)
1989 {
1990         read_lock(gl_lock_addr(gi->hash));
1991         while (1) {
1992                 if (!gi->hb_list) {  /* If we don't have a hash bucket yet */
1993                         gi->hb_list = &gl_hash_table[gi->hash].hb_list;
1994                         if (hlist_empty(gi->hb_list)) {
1995                                 read_unlock(gl_lock_addr(gi->hash));
1996                                 gi->hash++;
1997                                 read_lock(gl_lock_addr(gi->hash));
1998                                 gi->hb_list = NULL;
1999                                 if (gi->hash >= GFS2_GL_HASH_SIZE) {
2000                                         read_unlock(gl_lock_addr(gi->hash));
2001                                         return 1;
2002                                 }
2003                                 else
2004                                         continue;
2005                         }
2006                         if (!hlist_empty(gi->hb_list)) {
2007                                 gi->gl = list_entry(gi->hb_list->first,
2008                                                     struct gfs2_glock,
2009                                                     gl_list);
2010                         }
2011                 } else {
2012                         if (gi->gl->gl_list.next == NULL) {
2013                                 read_unlock(gl_lock_addr(gi->hash));
2014                                 gi->hash++;
2015                                 read_lock(gl_lock_addr(gi->hash));
2016                                 gi->hb_list = NULL;
2017                                 continue;
2018                         }
2019                         gi->gl = list_entry(gi->gl->gl_list.next,
2020                                             struct gfs2_glock, gl_list);
2021                 }
2022                 if (gi->gl)
2023                         break;
2024         }
2025         read_unlock(gl_lock_addr(gi->hash));
2026         return 0;
2027 }
2028
2029 static void gfs2_glock_iter_free(struct glock_iter *gi)
2030 {
2031         kfree(gi);
2032 }
2033
2034 static struct glock_iter *gfs2_glock_iter_init(struct gfs2_sbd *sdp)
2035 {
2036         struct glock_iter *gi;
2037
2038         gi = kmalloc(sizeof (*gi), GFP_KERNEL);
2039         if (!gi)
2040                 return NULL;
2041
2042         gi->sdp = sdp;
2043         gi->hash = 0;
2044         gi->gl = NULL;
2045         gi->hb_list = NULL;
2046         gi->seq = NULL;
2047         memset(gi->string, 0, sizeof(gi->string));
2048
2049         if (gfs2_glock_iter_next(gi)) {
2050                 gfs2_glock_iter_free(gi);
2051                 return NULL;
2052         }
2053
2054         return gi;
2055 }
2056
2057 static void *gfs2_glock_seq_start(struct seq_file *file, loff_t *pos)
2058 {
2059         struct glock_iter *gi;
2060         loff_t n = *pos;
2061
2062         gi = gfs2_glock_iter_init(file->private);
2063         if (!gi)
2064                 return NULL;
2065
2066         while (n--) {
2067                 if (gfs2_glock_iter_next(gi)) {
2068                         gfs2_glock_iter_free(gi);
2069                         return NULL;
2070                 }
2071         }
2072
2073         return gi;
2074 }
2075
2076 static void *gfs2_glock_seq_next(struct seq_file *file, void *iter_ptr,
2077                                  loff_t *pos)
2078 {
2079         struct glock_iter *gi = iter_ptr;
2080
2081         (*pos)++;
2082
2083         if (gfs2_glock_iter_next(gi)) {
2084                 gfs2_glock_iter_free(gi);
2085                 return NULL;
2086         }
2087
2088         return gi;
2089 }
2090
2091 static void gfs2_glock_seq_stop(struct seq_file *file, void *iter_ptr)
2092 {
2093         /* nothing for now */
2094 }
2095
2096 static int gfs2_glock_seq_show(struct seq_file *file, void *iter_ptr)
2097 {
2098         struct glock_iter *gi = iter_ptr;
2099
2100         gi->seq = file;
2101         dump_glock(gi, gi->gl);
2102
2103         return 0;
2104 }
2105
2106 static struct seq_operations gfs2_glock_seq_ops = {
2107         .start = gfs2_glock_seq_start,
2108         .next  = gfs2_glock_seq_next,
2109         .stop  = gfs2_glock_seq_stop,
2110         .show  = gfs2_glock_seq_show,
2111 };
2112
2113 static int gfs2_debugfs_open(struct inode *inode, struct file *file)
2114 {
2115         struct seq_file *seq;
2116         int ret;
2117
2118         ret = seq_open(file, &gfs2_glock_seq_ops);
2119         if (ret)
2120                 return ret;
2121
2122         seq = file->private_data;
2123         seq->private = inode->i_private;
2124
2125         return 0;
2126 }
2127
2128 static const struct file_operations gfs2_debug_fops = {
2129         .owner   = THIS_MODULE,
2130         .open    = gfs2_debugfs_open,
2131         .read    = seq_read,
2132         .llseek  = seq_lseek,
2133         .release = seq_release
2134 };
2135
2136 int gfs2_create_debugfs_file(struct gfs2_sbd *sdp)
2137 {
2138         sdp->debugfs_dir = debugfs_create_dir(sdp->sd_table_name, gfs2_root);
2139         if (!sdp->debugfs_dir)
2140                 return -ENOMEM;
2141         sdp->debugfs_dentry_glocks = debugfs_create_file("glocks",
2142                                                          S_IFREG | S_IRUGO,
2143                                                          sdp->debugfs_dir, sdp,
2144                                                          &gfs2_debug_fops);
2145         if (!sdp->debugfs_dentry_glocks)
2146                 return -ENOMEM;
2147
2148         return 0;
2149 }
2150
2151 void gfs2_delete_debugfs_file(struct gfs2_sbd *sdp)
2152 {
2153         if (sdp && sdp->debugfs_dir) {
2154                 if (sdp->debugfs_dentry_glocks) {
2155                         debugfs_remove(sdp->debugfs_dentry_glocks);
2156                         sdp->debugfs_dentry_glocks = NULL;
2157                 }
2158                 debugfs_remove(sdp->debugfs_dir);
2159                 sdp->debugfs_dir = NULL;
2160         }
2161 }
2162
2163 int gfs2_register_debugfs(void)
2164 {
2165         gfs2_root = debugfs_create_dir("gfs2", NULL);
2166         return gfs2_root ? 0 : -ENOMEM;
2167 }
2168
2169 void gfs2_unregister_debugfs(void)
2170 {
2171         debugfs_remove(gfs2_root);
2172         gfs2_root = NULL;
2173 }