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[GFS2] Macros removal in gfs2.h
[GitHub/mt8127/android_kernel_alcatel_ttab.git] / fs / gfs2 / glock.c
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b3b94faa
DT		 1/*
2 * Copyright (C) Sistina Software, Inc. 1997-2003 All rights reserved.
3 * Copyright (C) 2004-2005 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 v.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/kref.h>
5c676f6d 19#include <linux/gfs2_ondisk.h>
b3b94faa
DT		 20#include <asm/semaphore.h>
21#include <asm/uaccess.h>
22
23#include "gfs2.h"
5c676f6d
SW		 24#include "lm_interface.h"
25#include "incore.h"
b3b94faa
DT		 26#include "glock.h"
27#include "glops.h"
28#include "inode.h"
29#include "lm.h"
30#include "lops.h"
31#include "meta_io.h"
32#include "quota.h"
33#include "super.h"
5c676f6d 34#include "util.h"
b3b94faa
DT		 35
36/* Must be kept in sync with the beginning of struct gfs2_glock */
37struct glock_plug {
38 struct list_head gl_list;
39 unsigned long gl_flags;
40};
41
42struct greedy {
43 struct gfs2_holder gr_gh;
44 struct work_struct gr_work;
45};
46
47typedef void (*glock_examiner) (struct gfs2_glock * gl);
48
49/**
50 * relaxed_state_ok - is a requested lock compatible with the current lock mode?
51 * @actual: the current state of the lock
52 * @requested: the lock state that was requested by the caller
53 * @flags: the modifier flags passed in by the caller
54 *
55 * Returns: 1 if the locks are compatible, 0 otherwise
56 */
57
58static inline int relaxed_state_ok(unsigned int actual, unsigned requested,
59 int flags)
60{
61 if (actual == requested)
62 return 1;
63
64 if (flags & GL_EXACT)
65 return 0;
66
67 if (actual == LM_ST_EXCLUSIVE && requested == LM_ST_SHARED)
68 return 1;
69
70 if (actual != LM_ST_UNLOCKED && (flags & LM_FLAG_ANY))
71 return 1;
72
73 return 0;
74}
75
76/**
77 * gl_hash() - Turn glock number into hash bucket number
78 * @lock: The glock number
79 *
80 * Returns: The number of the corresponding hash bucket
81 */
82
83static unsigned int gl_hash(struct lm_lockname *name)
84{
85 unsigned int h;
86
87 h = jhash(&name->ln_number, sizeof(uint64_t), 0);
88 h = jhash(&name->ln_type, sizeof(unsigned int), h);
89 h &= GFS2_GL_HASH_MASK;
90
91 return h;
92}
93
94/**
95 * glock_free() - Perform a few checks and then release struct gfs2_glock
96 * @gl: The glock to release
97 *
98 * Also calls lock module to release its internal structure for this glock.
99 *
100 */
101
102static void glock_free(struct gfs2_glock *gl)
103{
104 struct gfs2_sbd *sdp = gl->gl_sbd;
105 struct inode *aspace = gl->gl_aspace;
106
107 gfs2_lm_put_lock(sdp, gl->gl_lock);
108
109 if (aspace)
110 gfs2_aspace_put(aspace);
111
112 kmem_cache_free(gfs2_glock_cachep, gl);
b3b94faa
DT		 113}
114
115/**
116 * gfs2_glock_hold() - increment reference count on glock
117 * @gl: The glock to hold
118 *
119 */
120
121void gfs2_glock_hold(struct gfs2_glock *gl)
122{
123 kref_get(&gl->gl_ref);
124}
125
126/* All work is done after the return from kref_put() so we
127 can release the write_lock before the free. */
128
129static void kill_glock(struct kref *kref)
130{
131 struct gfs2_glock *gl = container_of(kref, struct gfs2_glock, gl_ref);
132 struct gfs2_sbd *sdp = gl->gl_sbd;
133
134 gfs2_assert(sdp, gl->gl_state == LM_ST_UNLOCKED);
135 gfs2_assert(sdp, list_empty(&gl->gl_reclaim));
136 gfs2_assert(sdp, list_empty(&gl->gl_holders));
137 gfs2_assert(sdp, list_empty(&gl->gl_waiters1));
138 gfs2_assert(sdp, list_empty(&gl->gl_waiters2));
139 gfs2_assert(sdp, list_empty(&gl->gl_waiters3));
140}
141
142/**
143 * gfs2_glock_put() - Decrement reference count on glock
144 * @gl: The glock to put
145 *
146 */
147
148int gfs2_glock_put(struct gfs2_glock *gl)
149{
150 struct gfs2_sbd *sdp = gl->gl_sbd;
151 struct gfs2_gl_hash_bucket *bucket = gl->gl_bucket;
152 int rv = 0;
153
f55ab26a 154 mutex_lock(&sdp->sd_invalidate_inodes_mutex);
b3b94faa
DT		 155
156 write_lock(&bucket->hb_lock);
157 if (kref_put(&gl->gl_ref, kill_glock)) {
158 list_del_init(&gl->gl_list);
159 write_unlock(&bucket->hb_lock);
160 glock_free(gl);
161 rv = 1;
162 goto out;
163 }
164 write_unlock(&bucket->hb_lock);
165 out:
f55ab26a 166 mutex_unlock(&sdp->sd_invalidate_inodes_mutex);
b3b94faa
DT		 167 return rv;
168}
169
170/**
171 * queue_empty - check to see if a glock's queue is empty
172 * @gl: the glock
173 * @head: the head of the queue to check
174 *
175 * This function protects the list in the event that a process already
176 * has a holder on the list and is adding a second holder for itself.
177 * The glmutex lock is what generally prevents processes from working
178 * on the same glock at once, but the special case of adding a second
179 * holder for yourself ("recursive" locking) doesn't involve locking
180 * glmutex, making the spin lock necessary.
181 *
182 * Returns: 1 if the queue is empty
183 */
184
185static inline int queue_empty(struct gfs2_glock *gl, struct list_head *head)
186{
187 int empty;
188 spin_lock(&gl->gl_spin);
189 empty = list_empty(head);
190 spin_unlock(&gl->gl_spin);
191 return empty;
192}
193
194/**
195 * search_bucket() - Find struct gfs2_glock by lock number
196 * @bucket: the bucket to search
197 * @name: The lock name
198 *
199 * Returns: NULL, or the struct gfs2_glock with the requested number
200 */
201
202static struct gfs2_glock *search_bucket(struct gfs2_gl_hash_bucket *bucket,
203 struct lm_lockname *name)
204{
205 struct gfs2_glock *gl;
206
207 list_for_each_entry(gl, &bucket->hb_list, gl_list) {
208 if (test_bit(GLF_PLUG, &gl->gl_flags))
209 continue;
210 if (!lm_name_equal(&gl->gl_name, name))
211 continue;
212
213 kref_get(&gl->gl_ref);
214
215 return gl;
216 }
217
218 return NULL;
219}
220
221/**
222 * gfs2_glock_find() - Find glock by lock number
223 * @sdp: The GFS2 superblock
224 * @name: The lock name
225 *
226 * Returns: NULL, or the struct gfs2_glock with the requested number
227 */
228
229struct gfs2_glock *gfs2_glock_find(struct gfs2_sbd *sdp,
230 struct lm_lockname *name)
231{
232 struct gfs2_gl_hash_bucket *bucket = &sdp->sd_gl_hash[gl_hash(name)];
233 struct gfs2_glock *gl;
234
235 read_lock(&bucket->hb_lock);
236 gl = search_bucket(bucket, name);
237 read_unlock(&bucket->hb_lock);
238
239 return gl;
240}
241
242/**
243 * gfs2_glock_get() - Get a glock, or create one if one doesn't exist
244 * @sdp: The GFS2 superblock
245 * @number: the lock number
246 * @glops: The glock_operations to use
247 * @create: If 0, don't create the glock if it doesn't exist
248 * @glp: the glock is returned here
249 *
250 * This does not lock a glock, just finds/creates structures for one.
251 *
252 * Returns: errno
253 */
254
255int gfs2_glock_get(struct gfs2_sbd *sdp, uint64_t number,
256 struct gfs2_glock_operations *glops, int create,
257 struct gfs2_glock **glp)
258{
259 struct lm_lockname name;
260 struct gfs2_glock *gl, *tmp;
261 struct gfs2_gl_hash_bucket *bucket;
262 int error;
263
264 name.ln_number = number;
265 name.ln_type = glops->go_type;
266 bucket = &sdp->sd_gl_hash[gl_hash(&name)];
267
268 read_lock(&bucket->hb_lock);
269 gl = search_bucket(bucket, &name);
270 read_unlock(&bucket->hb_lock);
271
272 if (gl || !create) {
273 *glp = gl;
274 return 0;
275 }
276
277 gl = kmem_cache_alloc(gfs2_glock_cachep, GFP_KERNEL);
278 if (!gl)
279 return -ENOMEM;
280
281 memset(gl, 0, sizeof(struct gfs2_glock));
282
283 INIT_LIST_HEAD(&gl->gl_list);
284 gl->gl_name = name;
285 kref_init(&gl->gl_ref);
286
287 spin_lock_init(&gl->gl_spin);
288
289 gl->gl_state = LM_ST_UNLOCKED;
290 INIT_LIST_HEAD(&gl->gl_holders);
291 INIT_LIST_HEAD(&gl->gl_waiters1);
292 INIT_LIST_HEAD(&gl->gl_waiters2);
293 INIT_LIST_HEAD(&gl->gl_waiters3);
294
295 gl->gl_ops = glops;
296
297 gl->gl_bucket = bucket;
298 INIT_LIST_HEAD(&gl->gl_reclaim);
299
300 gl->gl_sbd = sdp;
301
302 lops_init_le(&gl->gl_le, &gfs2_glock_lops);
303 INIT_LIST_HEAD(&gl->gl_ail_list);
304
305 /* If this glock protects actual on-disk data or metadata blocks,
306 create a VFS inode to manage the pages/buffers holding them. */
307 if (glops == &gfs2_inode_glops ||
308 glops == &gfs2_rgrp_glops ||
309 glops == &gfs2_meta_glops) {
310 gl->gl_aspace = gfs2_aspace_get(sdp);
311 if (!gl->gl_aspace) {
312 error = -ENOMEM;
313 goto fail;
314 }
315 }
316
317 error = gfs2_lm_get_lock(sdp, &name, &gl->gl_lock);
318 if (error)
319 goto fail_aspace;
320
b3b94faa
DT		 321 write_lock(&bucket->hb_lock);
322 tmp = search_bucket(bucket, &name);
323 if (tmp) {
324 write_unlock(&bucket->hb_lock);
325 glock_free(gl);
326 gl = tmp;
327 } else {
328 list_add_tail(&gl->gl_list, &bucket->hb_list);
329 write_unlock(&bucket->hb_lock);
330 }
331
332 *glp = gl;
333
334 return 0;
335
336 fail_aspace:
337 if (gl->gl_aspace)
338 gfs2_aspace_put(gl->gl_aspace);
339
340 fail:
341 kmem_cache_free(gfs2_glock_cachep, gl);
342
343 return error;
344}
345
346/**
347 * gfs2_holder_init - initialize a struct gfs2_holder in the default way
348 * @gl: the glock
349 * @state: the state we're requesting
350 * @flags: the modifier flags
351 * @gh: the holder structure
352 *
353 */
354
355void gfs2_holder_init(struct gfs2_glock *gl, unsigned int state, int flags,
356 struct gfs2_holder *gh)
357{
358 INIT_LIST_HEAD(&gh->gh_list);
359 gh->gh_gl = gl;
360 gh->gh_owner = (flags & GL_NEVER_RECURSE) ? NULL : current;
361 gh->gh_state = state;
362 gh->gh_flags = flags;
363 gh->gh_error = 0;
364 gh->gh_iflags = 0;
365 init_completion(&gh->gh_wait);
366
367 if (gh->gh_state == LM_ST_EXCLUSIVE)
368 gh->gh_flags |= GL_LOCAL_EXCL;
369
370 gfs2_glock_hold(gl);
371}
372
373/**
374 * gfs2_holder_reinit - reinitialize a struct gfs2_holder so we can requeue it
375 * @state: the state we're requesting
376 * @flags: the modifier flags
377 * @gh: the holder structure
378 *
379 * Don't mess with the glock.
380 *
381 */
382
383void gfs2_holder_reinit(unsigned int state, int flags, struct gfs2_holder *gh)
384{
385 gh->gh_state = state;
386 gh->gh_flags = flags;
387 if (gh->gh_state == LM_ST_EXCLUSIVE)
388 gh->gh_flags |= GL_LOCAL_EXCL;
389
390 gh->gh_iflags &= 1 << HIF_ALLOCED;
391}
392
393/**
394 * gfs2_holder_uninit - uninitialize a holder structure (drop glock reference)
395 * @gh: the holder structure
396 *
397 */
398
399void gfs2_holder_uninit(struct gfs2_holder *gh)
400{
401 gfs2_glock_put(gh->gh_gl);
402 gh->gh_gl = NULL;
403}
404
405/**
406 * gfs2_holder_get - get a struct gfs2_holder structure
407 * @gl: the glock
408 * @state: the state we're requesting
409 * @flags: the modifier flags
410 * @gfp_flags: __GFP_NOFAIL
411 *
412 * Figure out how big an impact this function has. Either:
413 * 1) Replace it with a cache of structures hanging off the struct gfs2_sbd
414 * 2) Leave it like it is
415 *
416 * Returns: the holder structure, NULL on ENOMEM
417 */
418
419struct gfs2_holder *gfs2_holder_get(struct gfs2_glock *gl, unsigned int state,
420 int flags, gfp_t gfp_flags)
421{
422 struct gfs2_holder *gh;
423
424 gh = kmalloc(sizeof(struct gfs2_holder), gfp_flags);
425 if (!gh)
426 return NULL;
427
428 gfs2_holder_init(gl, state, flags, gh);
429 set_bit(HIF_ALLOCED, &gh->gh_iflags);
430
431 return gh;
432}
433
434/**
435 * gfs2_holder_put - get rid of a struct gfs2_holder structure
436 * @gh: the holder structure
437 *
438 */
439
440void gfs2_holder_put(struct gfs2_holder *gh)
441{
442 gfs2_holder_uninit(gh);
443 kfree(gh);
444}
445
446/**
447 * handle_recurse - put other holder structures (marked recursive)
448 * into the holders list
449 * @gh: the holder structure
450 *
451 */
452
453static void handle_recurse(struct gfs2_holder *gh)
454{
455 struct gfs2_glock *gl = gh->gh_gl;
456 struct gfs2_sbd *sdp = gl->gl_sbd;
457 struct gfs2_holder *tmp_gh, *safe;
458 int found = 0;
459
460 if (gfs2_assert_warn(sdp, gh->gh_owner))
461 return;
462
463 list_for_each_entry_safe(tmp_gh, safe, &gl->gl_waiters3, gh_list) {
464 if (tmp_gh->gh_owner != gh->gh_owner)
465 continue;
466
467 gfs2_assert_warn(sdp,
468 test_bit(HIF_RECURSE, &tmp_gh->gh_iflags));
469
470 list_move_tail(&tmp_gh->gh_list, &gl->gl_holders);
471 tmp_gh->gh_error = 0;
472 set_bit(HIF_HOLDER, &tmp_gh->gh_iflags);
473
474 complete(&tmp_gh->gh_wait);
475
476 found = 1;
477 }
478
479 gfs2_assert_warn(sdp, found);
480}
481
482/**
483 * do_unrecurse - a recursive holder was just dropped of the waiters3 list
484 * @gh: the holder
485 *
486 * If there is only one other recursive holder, clear its HIF_RECURSE bit.
487 * If there is more than one, leave them alone.
488 *
489 */
490
491static void do_unrecurse(struct gfs2_holder *gh)
492{
493 struct gfs2_glock *gl = gh->gh_gl;
494 struct gfs2_sbd *sdp = gl->gl_sbd;
495 struct gfs2_holder *tmp_gh, *last_gh = NULL;
496 int found = 0;
497
498 if (gfs2_assert_warn(sdp, gh->gh_owner))
499 return;
500
501 list_for_each_entry(tmp_gh, &gl->gl_waiters3, gh_list) {
502 if (tmp_gh->gh_owner != gh->gh_owner)
503 continue;
504
505 gfs2_assert_warn(sdp,
506 test_bit(HIF_RECURSE, &tmp_gh->gh_iflags));
507
508 if (found)
509 return;
510
511 found = 1;
512 last_gh = tmp_gh;
513 }
514
515 if (!gfs2_assert_warn(sdp, found))
516 clear_bit(HIF_RECURSE, &last_gh->gh_iflags);
517}
518
519/**
520 * rq_mutex - process a mutex request in the queue
521 * @gh: the glock holder
522 *
523 * Returns: 1 if the queue is blocked
524 */
525
526static int rq_mutex(struct gfs2_holder *gh)
527{
528 struct gfs2_glock *gl = gh->gh_gl;
529
530 list_del_init(&gh->gh_list);
531 /* gh->gh_error never examined. */
532 set_bit(GLF_LOCK, &gl->gl_flags);
533 complete(&gh->gh_wait);
534
535 return 1;
536}
537
538/**
539 * rq_promote - process a promote request in the queue
540 * @gh: the glock holder
541 *
542 * Acquire a new inter-node lock, or change a lock state to more restrictive.
543 *
544 * Returns: 1 if the queue is blocked
545 */
546
547static int rq_promote(struct gfs2_holder *gh)
548{
549 struct gfs2_glock *gl = gh->gh_gl;
550 struct gfs2_sbd *sdp = gl->gl_sbd;
551 struct gfs2_glock_operations *glops = gl->gl_ops;
552 int recurse;
553
554 if (!relaxed_state_ok(gl->gl_state, gh->gh_state, gh->gh_flags)) {
555 if (list_empty(&gl->gl_holders)) {
556 gl->gl_req_gh = gh;
557 set_bit(GLF_LOCK, &gl->gl_flags);
558 spin_unlock(&gl->gl_spin);
559
560 if (atomic_read(&sdp->sd_reclaim_count) >
561 gfs2_tune_get(sdp, gt_reclaim_limit) &&
562 !(gh->gh_flags & LM_FLAG_PRIORITY)) {
563 gfs2_reclaim_glock(sdp);
564 gfs2_reclaim_glock(sdp);
565 }
566
567 glops->go_xmote_th(gl, gh->gh_state,
568 gh->gh_flags);
569
570 spin_lock(&gl->gl_spin);
571 }
572 return 1;
573 }
574
575 if (list_empty(&gl->gl_holders)) {
576 set_bit(HIF_FIRST, &gh->gh_iflags);
577 set_bit(GLF_LOCK, &gl->gl_flags);
578 recurse = 0;
579 } else {
580 struct gfs2_holder *next_gh;
581 if (gh->gh_flags & GL_LOCAL_EXCL)
582 return 1;
583 next_gh = list_entry(gl->gl_holders.next, struct gfs2_holder,
584 gh_list);
585 if (next_gh->gh_flags & GL_LOCAL_EXCL)
586 return 1;
587 recurse = test_bit(HIF_RECURSE, &gh->gh_iflags);
588 }
589
590 list_move_tail(&gh->gh_list, &gl->gl_holders);
591 gh->gh_error = 0;
592 set_bit(HIF_HOLDER, &gh->gh_iflags);
593
594 if (recurse)
595 handle_recurse(gh);
596
597 complete(&gh->gh_wait);
598
599 return 0;
600}
601
602/**
603 * rq_demote - process a demote request in the queue
604 * @gh: the glock holder
605 *
606 * Returns: 1 if the queue is blocked
607 */
608
609static int rq_demote(struct gfs2_holder *gh)
610{
611 struct gfs2_glock *gl = gh->gh_gl;
612 struct gfs2_glock_operations *glops = gl->gl_ops;
613
614 if (!list_empty(&gl->gl_holders))
615 return 1;
616
617 if (gl->gl_state == gh->gh_state || gl->gl_state == LM_ST_UNLOCKED) {
618 list_del_init(&gh->gh_list);
619 gh->gh_error = 0;
620 spin_unlock(&gl->gl_spin);
621 if (test_bit(HIF_DEALLOC, &gh->gh_iflags))
622 gfs2_holder_put(gh);
623 else
624 complete(&gh->gh_wait);
625 spin_lock(&gl->gl_spin);
626 } else {
627 gl->gl_req_gh = gh;
628 set_bit(GLF_LOCK, &gl->gl_flags);
629 spin_unlock(&gl->gl_spin);
630
631 if (gh->gh_state == LM_ST_UNLOCKED ||
632 gl->gl_state != LM_ST_EXCLUSIVE)
633 glops->go_drop_th(gl);
634 else
635 glops->go_xmote_th(gl, gh->gh_state, gh->gh_flags);
636
637 spin_lock(&gl->gl_spin);
638 }
639
640 return 0;
641}
642
643/**
644 * rq_greedy - process a queued request to drop greedy status
645 * @gh: the glock holder
646 *
647 * Returns: 1 if the queue is blocked
648 */
649
650static int rq_greedy(struct gfs2_holder *gh)
651{
652 struct gfs2_glock *gl = gh->gh_gl;
653
654 list_del_init(&gh->gh_list);
655 /* gh->gh_error never examined. */
656 clear_bit(GLF_GREEDY, &gl->gl_flags);
657 spin_unlock(&gl->gl_spin);
658
659 gfs2_holder_uninit(gh);
660 kfree(container_of(gh, struct greedy, gr_gh));
661
662 spin_lock(&gl->gl_spin);
663
664 return 0;
665}
666
667/**
668 * run_queue - process holder structures on a glock
669 * @gl: the glock
670 *
671 */
672
673static void run_queue(struct gfs2_glock *gl)
674{
675 struct gfs2_holder *gh;
676 int blocked = 1;
677
678 for (;;) {
679 if (test_bit(GLF_LOCK, &gl->gl_flags))
680 break;
681
682 if (!list_empty(&gl->gl_waiters1)) {
683 gh = list_entry(gl->gl_waiters1.next,
684 struct gfs2_holder, gh_list);
685
686 if (test_bit(HIF_MUTEX, &gh->gh_iflags))
687 blocked = rq_mutex(gh);
688 else
689 gfs2_assert_warn(gl->gl_sbd, 0);
690
691 } else if (!list_empty(&gl->gl_waiters2) &&
692 !test_bit(GLF_SKIP_WAITERS2, &gl->gl_flags)) {
693 gh = list_entry(gl->gl_waiters2.next,
694 struct gfs2_holder, gh_list);
695
696 if (test_bit(HIF_DEMOTE, &gh->gh_iflags))
697 blocked = rq_demote(gh);
698 else if (test_bit(HIF_GREEDY, &gh->gh_iflags))
699 blocked = rq_greedy(gh);
700 else
701 gfs2_assert_warn(gl->gl_sbd, 0);
702
703 } else if (!list_empty(&gl->gl_waiters3)) {
704 gh = list_entry(gl->gl_waiters3.next,
705 struct gfs2_holder, gh_list);
706
707 if (test_bit(HIF_PROMOTE, &gh->gh_iflags))
708 blocked = rq_promote(gh);
709 else
710 gfs2_assert_warn(gl->gl_sbd, 0);
711
712 } else
713 break;
714
715 if (blocked)
716 break;
717 }
718}
719
720/**
721 * gfs2_glmutex_lock - acquire a local lock on a glock
722 * @gl: the glock
723 *
724 * Gives caller exclusive access to manipulate a glock structure.
725 */
726
727void gfs2_glmutex_lock(struct gfs2_glock *gl)
728{
729 struct gfs2_holder gh;
730
731 gfs2_holder_init(gl, 0, 0, &gh);
732 set_bit(HIF_MUTEX, &gh.gh_iflags);
733
734 spin_lock(&gl->gl_spin);
735 if (test_and_set_bit(GLF_LOCK, &gl->gl_flags))
736 list_add_tail(&gh.gh_list, &gl->gl_waiters1);
737 else
738 complete(&gh.gh_wait);
739 spin_unlock(&gl->gl_spin);
740
741 wait_for_completion(&gh.gh_wait);
742 gfs2_holder_uninit(&gh);
743}
744
745/**
746 * gfs2_glmutex_trylock - try to acquire a local lock on a glock
747 * @gl: the glock
748 *
749 * Returns: 1 if the glock is acquired
750 */
751
752int gfs2_glmutex_trylock(struct gfs2_glock *gl)
753{
754 int acquired = 1;
755
756 spin_lock(&gl->gl_spin);
757 if (test_and_set_bit(GLF_LOCK, &gl->gl_flags))
758 acquired = 0;
759 spin_unlock(&gl->gl_spin);
760
761 return acquired;
762}
763
764/**
765 * gfs2_glmutex_unlock - release a local lock on a glock
766 * @gl: the glock
767 *
768 */
769
770void gfs2_glmutex_unlock(struct gfs2_glock *gl)
771{
772 spin_lock(&gl->gl_spin);
773 clear_bit(GLF_LOCK, &gl->gl_flags);
774 run_queue(gl);
775 spin_unlock(&gl->gl_spin);
776}
777
778/**
779 * handle_callback - add a demote request to a lock's queue
780 * @gl: the glock
781 * @state: the state the caller wants us to change to
782 *
783 */
784
785static void handle_callback(struct gfs2_glock *gl, unsigned int state)
786{
787 struct gfs2_holder *gh, *new_gh = NULL;
788
789 restart:
790 spin_lock(&gl->gl_spin);
791
792 list_for_each_entry(gh, &gl->gl_waiters2, gh_list) {
793 if (test_bit(HIF_DEMOTE, &gh->gh_iflags) &&
794 gl->gl_req_gh != gh) {
795 if (gh->gh_state != state)
796 gh->gh_state = LM_ST_UNLOCKED;
797 goto out;
798 }
799 }
800
801 if (new_gh) {
802 list_add_tail(&new_gh->gh_list, &gl->gl_waiters2);
803 new_gh = NULL;
804 } else {
805 spin_unlock(&gl->gl_spin);
806
807 new_gh = gfs2_holder_get(gl, state,
808 LM_FLAG_TRY | GL_NEVER_RECURSE,
809 GFP_KERNEL | __GFP_NOFAIL),
810 set_bit(HIF_DEMOTE, &new_gh->gh_iflags);
811 set_bit(HIF_DEALLOC, &new_gh->gh_iflags);
812
813 goto restart;
814 }
815
816 out:
817 spin_unlock(&gl->gl_spin);
818
819 if (new_gh)
820 gfs2_holder_put(new_gh);
821}
822
823/**
824 * state_change - record that the glock is now in a different state
825 * @gl: the glock
826 * @new_state the new state
827 *
828 */
829
830static void state_change(struct gfs2_glock *gl, unsigned int new_state)
831{
b3b94faa
DT		 832 int held1, held2;
833
834 held1 = (gl->gl_state != LM_ST_UNLOCKED);
835 held2 = (new_state != LM_ST_UNLOCKED);
836
837 if (held1 != held2) {
6a6b3d01 838 if (held2)
b3b94faa 839 gfs2_glock_hold(gl);
6a6b3d01 840 else
b3b94faa 841 gfs2_glock_put(gl);
b3b94faa
DT		 842 }
843
844 gl->gl_state = new_state;
845}
846
847/**
848 * xmote_bh - Called after the lock module is done acquiring a lock
849 * @gl: The glock in question
850 * @ret: the int returned from the lock module
851 *
852 */
853
854static void xmote_bh(struct gfs2_glock *gl, unsigned int ret)
855{
856 struct gfs2_sbd *sdp = gl->gl_sbd;
857 struct gfs2_glock_operations *glops = gl->gl_ops;
858 struct gfs2_holder *gh = gl->gl_req_gh;
859 int prev_state = gl->gl_state;
860 int op_done = 1;
861
862 gfs2_assert_warn(sdp, test_bit(GLF_LOCK, &gl->gl_flags));
863 gfs2_assert_warn(sdp, queue_empty(gl, &gl->gl_holders));
864 gfs2_assert_warn(sdp, !(ret & LM_OUT_ASYNC));
865
866 state_change(gl, ret & LM_OUT_ST_MASK);
867
868 if (prev_state != LM_ST_UNLOCKED && !(ret & LM_OUT_CACHEABLE)) {
869 if (glops->go_inval)
870 glops->go_inval(gl, DIO_METADATA | DIO_DATA);
871 } else if (gl->gl_state == LM_ST_DEFERRED) {
872 /* We might not want to do this here.
873 Look at moving to the inode glops. */
874 if (glops->go_inval)
875 glops->go_inval(gl, DIO_DATA);
876 }
877
878 /* Deal with each possible exit condition */
879
880 if (!gh)
881 gl->gl_stamp = jiffies;
882
883 else if (unlikely(test_bit(SDF_SHUTDOWN, &sdp->sd_flags))) {
884 spin_lock(&gl->gl_spin);
885 list_del_init(&gh->gh_list);
886 gh->gh_error = -EIO;
887 if (test_bit(HIF_RECURSE, &gh->gh_iflags))
888 do_unrecurse(gh);
889 spin_unlock(&gl->gl_spin);
890
891 } else if (test_bit(HIF_DEMOTE, &gh->gh_iflags)) {
892 spin_lock(&gl->gl_spin);
893 list_del_init(&gh->gh_list);
894 if (gl->gl_state == gh->gh_state ||
895 gl->gl_state == LM_ST_UNLOCKED)
896 gh->gh_error = 0;
897 else {
898 if (gfs2_assert_warn(sdp, gh->gh_flags &
899 (LM_FLAG_TRY | LM_FLAG_TRY_1CB)) == -1)
900 fs_warn(sdp, "ret = 0x%.8X\n", ret);
901 gh->gh_error = GLR_TRYFAILED;
902 }
903 spin_unlock(&gl->gl_spin);
904
905 if (ret & LM_OUT_CANCELED)
906 handle_callback(gl, LM_ST_UNLOCKED); /* Lame */
907
908 } else if (ret & LM_OUT_CANCELED) {
909 spin_lock(&gl->gl_spin);
910 list_del_init(&gh->gh_list);
911 gh->gh_error = GLR_CANCELED;
912 if (test_bit(HIF_RECURSE, &gh->gh_iflags))
913 do_unrecurse(gh);
914 spin_unlock(&gl->gl_spin);
915
916 } else if (relaxed_state_ok(gl->gl_state, gh->gh_state, gh->gh_flags)) {
917 spin_lock(&gl->gl_spin);
918 list_move_tail(&gh->gh_list, &gl->gl_holders);
919 gh->gh_error = 0;
920 set_bit(HIF_HOLDER, &gh->gh_iflags);
921 spin_unlock(&gl->gl_spin);
922
923 set_bit(HIF_FIRST, &gh->gh_iflags);
924
925 op_done = 0;
926
927 } else if (gh->gh_flags & (LM_FLAG_TRY | LM_FLAG_TRY_1CB)) {
928 spin_lock(&gl->gl_spin);
929 list_del_init(&gh->gh_list);
930 gh->gh_error = GLR_TRYFAILED;
931 if (test_bit(HIF_RECURSE, &gh->gh_iflags))
932 do_unrecurse(gh);
933 spin_unlock(&gl->gl_spin);
934
935 } else {
936 if (gfs2_assert_withdraw(sdp, 0) == -1)
937 fs_err(sdp, "ret = 0x%.8X\n", ret);
938 }
939
940 if (glops->go_xmote_bh)
941 glops->go_xmote_bh(gl);
942
943 if (op_done) {
944 spin_lock(&gl->gl_spin);
945 gl->gl_req_gh = NULL;
946 gl->gl_req_bh = NULL;
947 clear_bit(GLF_LOCK, &gl->gl_flags);
948 run_queue(gl);
949 spin_unlock(&gl->gl_spin);
950 }
951
952 gfs2_glock_put(gl);
953
954 if (gh) {
955 if (test_bit(HIF_DEALLOC, &gh->gh_iflags))
956 gfs2_holder_put(gh);
957 else
958 complete(&gh->gh_wait);
959 }
960}
961
962/**
963 * gfs2_glock_xmote_th - Call into the lock module to acquire or change a glock
964 * @gl: The glock in question
965 * @state: the requested state
966 * @flags: modifier flags to the lock call
967 *
968 */
969
970void gfs2_glock_xmote_th(struct gfs2_glock *gl, unsigned int state, int flags)
971{
972 struct gfs2_sbd *sdp = gl->gl_sbd;
973 struct gfs2_glock_operations *glops = gl->gl_ops;
974 int lck_flags = flags & (LM_FLAG_TRY | LM_FLAG_TRY_1CB |
975 LM_FLAG_NOEXP | LM_FLAG_ANY |
976 LM_FLAG_PRIORITY);
977 unsigned int lck_ret;
978
979 gfs2_assert_warn(sdp, test_bit(GLF_LOCK, &gl->gl_flags));
980 gfs2_assert_warn(sdp, queue_empty(gl, &gl->gl_holders));
981 gfs2_assert_warn(sdp, state != LM_ST_UNLOCKED);
982 gfs2_assert_warn(sdp, state != gl->gl_state);
983
984 if (gl->gl_state == LM_ST_EXCLUSIVE) {
985 if (glops->go_sync)
986 glops->go_sync(gl,
987 DIO_METADATA | DIO_DATA | DIO_RELEASE);
988 }
989
990 gfs2_glock_hold(gl);
991 gl->gl_req_bh = xmote_bh;
992
b3b94faa
DT		 993 lck_ret = gfs2_lm_lock(sdp, gl->gl_lock, gl->gl_state, state,
994 lck_flags);
995
996 if (gfs2_assert_withdraw(sdp, !(lck_ret & LM_OUT_ERROR)))
997 return;
998
999 if (lck_ret & LM_OUT_ASYNC)
1000 gfs2_assert_warn(sdp, lck_ret == LM_OUT_ASYNC);
1001 else
1002 xmote_bh(gl, lck_ret);
1003}
1004
1005/**
1006 * drop_bh - Called after a lock module unlock completes
1007 * @gl: the glock
1008 * @ret: the return status
1009 *
1010 * Doesn't wake up the process waiting on the struct gfs2_holder (if any)
1011 * Doesn't drop the reference on the glock the top half took out
1012 *
1013 */
1014
1015static void drop_bh(struct gfs2_glock *gl, unsigned int ret)
1016{
1017 struct gfs2_sbd *sdp = gl->gl_sbd;
1018 struct gfs2_glock_operations *glops = gl->gl_ops;
1019 struct gfs2_holder *gh = gl->gl_req_gh;
1020
1021 clear_bit(GLF_PREFETCH, &gl->gl_flags);
1022
1023 gfs2_assert_warn(sdp, test_bit(GLF_LOCK, &gl->gl_flags));
1024 gfs2_assert_warn(sdp, queue_empty(gl, &gl->gl_holders));
1025 gfs2_assert_warn(sdp, !ret);
1026
1027 state_change(gl, LM_ST_UNLOCKED);
1028
1029 if (glops->go_inval)
1030 glops->go_inval(gl, DIO_METADATA | DIO_DATA);
1031
1032 if (gh) {
1033 spin_lock(&gl->gl_spin);
1034 list_del_init(&gh->gh_list);
1035 gh->gh_error = 0;
1036 spin_unlock(&gl->gl_spin);
1037 }
1038
1039 if (glops->go_drop_bh)
1040 glops->go_drop_bh(gl);
1041
1042 spin_lock(&gl->gl_spin);
1043 gl->gl_req_gh = NULL;
1044 gl->gl_req_bh = NULL;
1045 clear_bit(GLF_LOCK, &gl->gl_flags);
1046 run_queue(gl);
1047 spin_unlock(&gl->gl_spin);
1048
1049 gfs2_glock_put(gl);
1050
1051 if (gh) {
1052 if (test_bit(HIF_DEALLOC, &gh->gh_iflags))
1053 gfs2_holder_put(gh);
1054 else
1055 complete(&gh->gh_wait);
1056 }
1057}
1058
1059/**
1060 * gfs2_glock_drop_th - call into the lock module to unlock a lock
1061 * @gl: the glock
1062 *
1063 */
1064
1065void gfs2_glock_drop_th(struct gfs2_glock *gl)
1066{
1067 struct gfs2_sbd *sdp = gl->gl_sbd;
1068 struct gfs2_glock_operations *glops = gl->gl_ops;
1069 unsigned int ret;
1070
1071 gfs2_assert_warn(sdp, test_bit(GLF_LOCK, &gl->gl_flags));
1072 gfs2_assert_warn(sdp, queue_empty(gl, &gl->gl_holders));
1073 gfs2_assert_warn(sdp, gl->gl_state != LM_ST_UNLOCKED);
1074
1075 if (gl->gl_state == LM_ST_EXCLUSIVE) {
1076 if (glops->go_sync)
1077 glops->go_sync(gl,
1078 DIO_METADATA | DIO_DATA | DIO_RELEASE);
1079 }
1080
1081 gfs2_glock_hold(gl);
1082 gl->gl_req_bh = drop_bh;
1083
b3b94faa
DT		 1084 ret = gfs2_lm_unlock(sdp, gl->gl_lock, gl->gl_state);
1085
1086 if (gfs2_assert_withdraw(sdp, !(ret & LM_OUT_ERROR)))
1087 return;
1088
1089 if (!ret)
1090 drop_bh(gl, ret);
1091 else
1092 gfs2_assert_warn(sdp, ret == LM_OUT_ASYNC);
1093}
1094
1095/**
1096 * do_cancels - cancel requests for locks stuck waiting on an expire flag
1097 * @gh: the LM_FLAG_PRIORITY holder waiting to acquire the lock
1098 *
1099 * Don't cancel GL_NOCANCEL requests.
1100 */
1101
1102static void do_cancels(struct gfs2_holder *gh)
1103{
1104 struct gfs2_glock *gl = gh->gh_gl;
1105
1106 spin_lock(&gl->gl_spin);
1107
1108 while (gl->gl_req_gh != gh &&
1109 !test_bit(HIF_HOLDER, &gh->gh_iflags) &&
1110 !list_empty(&gh->gh_list)) {
1111 if (gl->gl_req_bh &&
1112 !(gl->gl_req_gh &&
1113 (gl->gl_req_gh->gh_flags & GL_NOCANCEL))) {
1114 spin_unlock(&gl->gl_spin);
1115 gfs2_lm_cancel(gl->gl_sbd, gl->gl_lock);
1116 msleep(100);
1117 spin_lock(&gl->gl_spin);
1118 } else {
1119 spin_unlock(&gl->gl_spin);
1120 msleep(100);
1121 spin_lock(&gl->gl_spin);
1122 }
1123 }
1124
1125 spin_unlock(&gl->gl_spin);
1126}
1127
1128/**
1129 * glock_wait_internal - wait on a glock acquisition
1130 * @gh: the glock holder
1131 *
1132 * Returns: 0 on success
1133 */
1134
1135static int glock_wait_internal(struct gfs2_holder *gh)
1136{
1137 struct gfs2_glock *gl = gh->gh_gl;
1138 struct gfs2_sbd *sdp = gl->gl_sbd;
1139 struct gfs2_glock_operations *glops = gl->gl_ops;
1140
1141 if (test_bit(HIF_ABORTED, &gh->gh_iflags))
1142 return -EIO;
1143
1144 if (gh->gh_flags & (LM_FLAG_TRY | LM_FLAG_TRY_1CB)) {
1145 spin_lock(&gl->gl_spin);
1146 if (gl->gl_req_gh != gh &&
1147 !test_bit(HIF_HOLDER, &gh->gh_iflags) &&
1148 !list_empty(&gh->gh_list)) {
1149 list_del_init(&gh->gh_list);
1150 gh->gh_error = GLR_TRYFAILED;
1151 if (test_bit(HIF_RECURSE, &gh->gh_iflags))
1152 do_unrecurse(gh);
1153 run_queue(gl);
1154 spin_unlock(&gl->gl_spin);
1155 return gh->gh_error;
1156 }
1157 spin_unlock(&gl->gl_spin);
1158 }
1159
1160 if (gh->gh_flags & LM_FLAG_PRIORITY)
1161 do_cancels(gh);
1162
1163 wait_for_completion(&gh->gh_wait);
1164
1165 if (gh->gh_error)
1166 return gh->gh_error;
1167
1168 gfs2_assert_withdraw(sdp, test_bit(HIF_HOLDER, &gh->gh_iflags));
1169 gfs2_assert_withdraw(sdp, relaxed_state_ok(gl->gl_state,
1170 gh->gh_state,
1171 gh->gh_flags));
1172
1173 if (test_bit(HIF_FIRST, &gh->gh_iflags)) {
1174 gfs2_assert_warn(sdp, test_bit(GLF_LOCK, &gl->gl_flags));
1175
1176 if (glops->go_lock) {
1177 gh->gh_error = glops->go_lock(gh);
1178 if (gh->gh_error) {
1179 spin_lock(&gl->gl_spin);
1180 list_del_init(&gh->gh_list);
1181 if (test_and_clear_bit(HIF_RECURSE,
1182 &gh->gh_iflags))
1183 do_unrecurse(gh);
1184 spin_unlock(&gl->gl_spin);
1185 }
1186 }
1187
1188 spin_lock(&gl->gl_spin);
1189 gl->gl_req_gh = NULL;
1190 gl->gl_req_bh = NULL;
1191 clear_bit(GLF_LOCK, &gl->gl_flags);
1192 if (test_bit(HIF_RECURSE, &gh->gh_iflags))
1193 handle_recurse(gh);
1194 run_queue(gl);
1195 spin_unlock(&gl->gl_spin);
1196 }
1197
1198 return gh->gh_error;
1199}
1200
1201static inline struct gfs2_holder *
1202find_holder_by_owner(struct list_head *head, struct task_struct *owner)
1203{
1204 struct gfs2_holder *gh;
1205
1206 list_for_each_entry(gh, head, gh_list) {
1207 if (gh->gh_owner == owner)
1208 return gh;
1209 }
1210
1211 return NULL;
1212}
1213
1214/**
1215 * recurse_check -
1216 *
1217 * Make sure the new holder is compatible with the pre-existing one.
1218 *
1219 */
1220
1221static int recurse_check(struct gfs2_holder *existing, struct gfs2_holder *new,
1222 unsigned int state)
1223{
1224 struct gfs2_sbd *sdp = existing->gh_gl->gl_sbd;
1225
1226 if (gfs2_assert_warn(sdp, (new->gh_flags & LM_FLAG_ANY) ||
1227 !(existing->gh_flags & LM_FLAG_ANY)))
1228 goto fail;
1229
1230 if (gfs2_assert_warn(sdp, (existing->gh_flags & GL_LOCAL_EXCL) ||
1231 !(new->gh_flags & GL_LOCAL_EXCL)))
1232 goto fail;
1233
1234 if (gfs2_assert_warn(sdp, relaxed_state_ok(state, new->gh_state,
1235 new->gh_flags)))
1236 goto fail;
1237
1238 return 0;
1239
1240 fail:
1241 set_bit(HIF_ABORTED, &new->gh_iflags);
1242 return -EINVAL;
1243}
1244
1245/**
1246 * add_to_queue - Add a holder to the wait queue (but look for recursion)
1247 * @gh: the holder structure to add
1248 *
1249 */
1250
1251static void add_to_queue(struct gfs2_holder *gh)
1252{
1253 struct gfs2_glock *gl = gh->gh_gl;
1254 struct gfs2_holder *existing;
1255
1256 if (!gh->gh_owner)
1257 goto out;
1258
1259 existing = find_holder_by_owner(&gl->gl_holders, gh->gh_owner);
1260 if (existing) {
1261 if (recurse_check(existing, gh, gl->gl_state))
1262 return;
1263
1264 list_add_tail(&gh->gh_list, &gl->gl_holders);
1265 set_bit(HIF_HOLDER, &gh->gh_iflags);
1266
1267 gh->gh_error = 0;
1268 complete(&gh->gh_wait);
1269
1270 return;
1271 }
1272
1273 existing = find_holder_by_owner(&gl->gl_waiters3, gh->gh_owner);
1274 if (existing) {
1275 if (recurse_check(existing, gh, existing->gh_state))
1276 return;
1277
1278 set_bit(HIF_RECURSE, &gh->gh_iflags);
1279 set_bit(HIF_RECURSE, &existing->gh_iflags);
1280
1281 list_add_tail(&gh->gh_list, &gl->gl_waiters3);
1282
1283 return;
1284 }
1285
1286 out:
1287 if (gh->gh_flags & LM_FLAG_PRIORITY)
1288 list_add(&gh->gh_list, &gl->gl_waiters3);
1289 else
1290 list_add_tail(&gh->gh_list, &gl->gl_waiters3);
1291}
1292
1293/**
1294 * gfs2_glock_nq - enqueue a struct gfs2_holder onto a glock (acquire a glock)
1295 * @gh: the holder structure
1296 *
1297 * if (gh->gh_flags & GL_ASYNC), this never returns an error
1298 *
1299 * Returns: 0, GLR_TRYFAILED, or errno on failure
1300 */
1301
1302int gfs2_glock_nq(struct gfs2_holder *gh)
1303{
1304 struct gfs2_glock *gl = gh->gh_gl;
1305 struct gfs2_sbd *sdp = gl->gl_sbd;
1306 int error = 0;
1307
b3b94faa
DT		 1308 restart:
1309 if (unlikely(test_bit(SDF_SHUTDOWN, &sdp->sd_flags))) {
1310 set_bit(HIF_ABORTED, &gh->gh_iflags);
1311 return -EIO;
1312 }
1313
1314 set_bit(HIF_PROMOTE, &gh->gh_iflags);
1315
1316 spin_lock(&gl->gl_spin);
1317 add_to_queue(gh);
1318 run_queue(gl);
1319 spin_unlock(&gl->gl_spin);
1320
1321 if (!(gh->gh_flags & GL_ASYNC)) {
1322 error = glock_wait_internal(gh);
1323 if (error == GLR_CANCELED) {
1324 msleep(1000);
1325 goto restart;
1326 }
1327 }
1328
1329 clear_bit(GLF_PREFETCH, &gl->gl_flags);
1330
1331 return error;
1332}
1333
1334/**
1335 * gfs2_glock_poll - poll to see if an async request has been completed
1336 * @gh: the holder
1337 *
1338 * Returns: 1 if the request is ready to be gfs2_glock_wait()ed on
1339 */
1340
1341int gfs2_glock_poll(struct gfs2_holder *gh)
1342{
1343 struct gfs2_glock *gl = gh->gh_gl;
1344 int ready = 0;
1345
1346 spin_lock(&gl->gl_spin);
1347
1348 if (test_bit(HIF_HOLDER, &gh->gh_iflags))
1349 ready = 1;
1350 else if (list_empty(&gh->gh_list)) {
1351 if (gh->gh_error == GLR_CANCELED) {
1352 spin_unlock(&gl->gl_spin);
1353 msleep(1000);
1354 if (gfs2_glock_nq(gh))
1355 return 1;
1356 return 0;
1357 } else
1358 ready = 1;
1359 }
1360
1361 spin_unlock(&gl->gl_spin);
1362
1363 return ready;
1364}
1365
1366/**
1367 * gfs2_glock_wait - wait for a lock acquisition that ended in a GLR_ASYNC
1368 * @gh: the holder structure
1369 *
1370 * Returns: 0, GLR_TRYFAILED, or errno on failure
1371 */
1372
1373int gfs2_glock_wait(struct gfs2_holder *gh)
1374{
1375 int error;
1376
1377 error = glock_wait_internal(gh);
1378 if (error == GLR_CANCELED) {
1379 msleep(1000);
1380 gh->gh_flags &= ~GL_ASYNC;
1381 error = gfs2_glock_nq(gh);
1382 }
1383
1384 return error;
1385}
1386
1387/**
1388 * gfs2_glock_dq - dequeue a struct gfs2_holder from a glock (release a glock)
1389 * @gh: the glock holder
1390 *
1391 */
1392
1393void gfs2_glock_dq(struct gfs2_holder *gh)
1394{
1395 struct gfs2_glock *gl = gh->gh_gl;
b3b94faa
DT		 1396 struct gfs2_glock_operations *glops = gl->gl_ops;
1397
b3b94faa
DT		 1398 if (gh->gh_flags & GL_SYNC)
1399 set_bit(GLF_SYNC, &gl->gl_flags);
1400
1401 if (gh->gh_flags & GL_NOCACHE)
1402 handle_callback(gl, LM_ST_UNLOCKED);
1403
1404 gfs2_glmutex_lock(gl);
1405
1406 spin_lock(&gl->gl_spin);
1407 list_del_init(&gh->gh_list);
1408
1409 if (list_empty(&gl->gl_holders)) {
1410 spin_unlock(&gl->gl_spin);
1411
1412 if (glops->go_unlock)
1413 glops->go_unlock(gh);
1414
1415 if (test_bit(GLF_SYNC, &gl->gl_flags)) {
1416 if (glops->go_sync)
1417 glops->go_sync(gl, DIO_METADATA | DIO_DATA);
1418 }
1419
1420 gl->gl_stamp = jiffies;
1421
1422 spin_lock(&gl->gl_spin);
1423 }
1424
1425 clear_bit(GLF_LOCK, &gl->gl_flags);
1426 run_queue(gl);
1427 spin_unlock(&gl->gl_spin);
1428}
1429
1430/**
1431 * gfs2_glock_prefetch - Try to prefetch a glock
1432 * @gl: the glock
1433 * @state: the state to prefetch in
1434 * @flags: flags passed to go_xmote_th()
1435 *
1436 */
1437
1438void gfs2_glock_prefetch(struct gfs2_glock *gl, unsigned int state, int flags)
1439{
1440 struct gfs2_glock_operations *glops = gl->gl_ops;
1441
1442 spin_lock(&gl->gl_spin);
1443
1444 if (test_bit(GLF_LOCK, &gl->gl_flags) ||
1445 !list_empty(&gl->gl_holders) ||
1446 !list_empty(&gl->gl_waiters1) ||
1447 !list_empty(&gl->gl_waiters2) ||
1448 !list_empty(&gl->gl_waiters3) ||
1449 relaxed_state_ok(gl->gl_state, state, flags)) {
1450 spin_unlock(&gl->gl_spin);
1451 return;
1452 }
1453
1454 set_bit(GLF_PREFETCH, &gl->gl_flags);
1455 set_bit(GLF_LOCK, &gl->gl_flags);
1456 spin_unlock(&gl->gl_spin);
1457
1458 glops->go_xmote_th(gl, state, flags);
b3b94faa
DT		 1459}
1460
1461/**
1462 * gfs2_glock_force_drop - Force a glock to be uncached
1463 * @gl: the glock
1464 *
1465 */
1466
1467void gfs2_glock_force_drop(struct gfs2_glock *gl)
1468{
1469 struct gfs2_holder gh;
1470
1471 gfs2_holder_init(gl, LM_ST_UNLOCKED, GL_NEVER_RECURSE, &gh);
1472 set_bit(HIF_DEMOTE, &gh.gh_iflags);
1473
1474 spin_lock(&gl->gl_spin);
1475 list_add_tail(&gh.gh_list, &gl->gl_waiters2);
1476 run_queue(gl);
1477 spin_unlock(&gl->gl_spin);
1478
1479 wait_for_completion(&gh.gh_wait);
1480 gfs2_holder_uninit(&gh);
1481}
1482
1483static void greedy_work(void *data)
1484{
1485 struct greedy *gr = (struct greedy *)data;
1486 struct gfs2_holder *gh = &gr->gr_gh;
1487 struct gfs2_glock *gl = gh->gh_gl;
1488 struct gfs2_glock_operations *glops = gl->gl_ops;
1489
1490 clear_bit(GLF_SKIP_WAITERS2, &gl->gl_flags);
1491
1492 if (glops->go_greedy)
1493 glops->go_greedy(gl);
1494
1495 spin_lock(&gl->gl_spin);
1496
1497 if (list_empty(&gl->gl_waiters2)) {
1498 clear_bit(GLF_GREEDY, &gl->gl_flags);
1499 spin_unlock(&gl->gl_spin);
1500 gfs2_holder_uninit(gh);
1501 kfree(gr);
1502 } else {
1503 gfs2_glock_hold(gl);
1504 list_add_tail(&gh->gh_list, &gl->gl_waiters2);
1505 run_queue(gl);
1506 spin_unlock(&gl->gl_spin);
1507 gfs2_glock_put(gl);
1508 }
1509}
1510
1511/**
1512 * gfs2_glock_be_greedy -
1513 * @gl:
1514 * @time:
1515 *
1516 * Returns: 0 if go_greedy will be called, 1 otherwise
1517 */
1518
1519int gfs2_glock_be_greedy(struct gfs2_glock *gl, unsigned int time)
1520{
1521 struct greedy *gr;
1522 struct gfs2_holder *gh;
1523
1524 if (!time ||
1525 gl->gl_sbd->sd_args.ar_localcaching ||
1526 test_and_set_bit(GLF_GREEDY, &gl->gl_flags))
1527 return 1;
1528
1529 gr = kmalloc(sizeof(struct greedy), GFP_KERNEL);
1530 if (!gr) {
1531 clear_bit(GLF_GREEDY, &gl->gl_flags);
1532 return 1;
1533 }
1534 gh = &gr->gr_gh;
1535
1536 gfs2_holder_init(gl, 0, GL_NEVER_RECURSE, gh);
1537 set_bit(HIF_GREEDY, &gh->gh_iflags);
1538 INIT_WORK(&gr->gr_work, greedy_work, gr);
1539
1540 set_bit(GLF_SKIP_WAITERS2, &gl->gl_flags);
1541 schedule_delayed_work(&gr->gr_work, time);
1542
1543 return 0;
1544}
1545
1546/**
1547 * gfs2_glock_nq_init - intialize a holder and enqueue it on a glock
1548 * @gl: the glock
1549 * @state: the state we're requesting
1550 * @flags: the modifier flags
1551 * @gh: the holder structure
1552 *
1553 * Returns: 0, GLR_*, or errno
1554 */
1555
1556int gfs2_glock_nq_init(struct gfs2_glock *gl, unsigned int state, int flags,
1557 struct gfs2_holder *gh)
1558{
1559 int error;
1560
1561 gfs2_holder_init(gl, state, flags, gh);
1562
1563 error = gfs2_glock_nq(gh);
1564 if (error)
1565 gfs2_holder_uninit(gh);
1566
1567 return error;
1568}
1569
1570/**
1571 * gfs2_glock_dq_uninit - dequeue a holder from a glock and initialize it
1572 * @gh: the holder structure
1573 *
1574 */
1575
1576void gfs2_glock_dq_uninit(struct gfs2_holder *gh)
1577{
1578 gfs2_glock_dq(gh);
1579 gfs2_holder_uninit(gh);
1580}
1581
1582/**
1583 * gfs2_glock_nq_num - acquire a glock based on lock number
1584 * @sdp: the filesystem
1585 * @number: the lock number
1586 * @glops: the glock operations for the type of glock
1587 * @state: the state to acquire the glock in
1588 * @flags: modifier flags for the aquisition
1589 * @gh: the struct gfs2_holder
1590 *
1591 * Returns: errno
1592 */
1593
1594int gfs2_glock_nq_num(struct gfs2_sbd *sdp, uint64_t number,
1595 struct gfs2_glock_operations *glops, unsigned int state,
1596 int flags, struct gfs2_holder *gh)
1597{
1598 struct gfs2_glock *gl;
1599 int error;
1600
1601 error = gfs2_glock_get(sdp, number, glops, CREATE, &gl);
1602 if (!error) {
1603 error = gfs2_glock_nq_init(gl, state, flags, gh);
1604 gfs2_glock_put(gl);
1605 }
1606
1607 return error;
1608}
1609
1610/**
1611 * glock_compare - Compare two struct gfs2_glock structures for sorting
1612 * @arg_a: the first structure
1613 * @arg_b: the second structure
1614 *
1615 */
1616
1617static int glock_compare(const void *arg_a, const void *arg_b)
1618{
1619 struct gfs2_holder *gh_a = *(struct gfs2_holder **)arg_a;
1620 struct gfs2_holder *gh_b = *(struct gfs2_holder **)arg_b;
1621 struct lm_lockname *a = &gh_a->gh_gl->gl_name;
1622 struct lm_lockname *b = &gh_b->gh_gl->gl_name;
1623 int ret = 0;
1624
1625 if (a->ln_number > b->ln_number)
1626 ret = 1;
1627 else if (a->ln_number < b->ln_number)
1628 ret = -1;
1629 else {
1630 if (gh_a->gh_state == LM_ST_SHARED &&
1631 gh_b->gh_state == LM_ST_EXCLUSIVE)
1632 ret = 1;
1633 else if (!(gh_a->gh_flags & GL_LOCAL_EXCL) &&
1634 (gh_b->gh_flags & GL_LOCAL_EXCL))
1635 ret = 1;
1636 }
1637
1638 return ret;
1639}
1640
1641/**
1642 * nq_m_sync - synchonously acquire more than one glock in deadlock free order
1643 * @num_gh: the number of structures
1644 * @ghs: an array of struct gfs2_holder structures
1645 *
1646 * Returns: 0 on success (all glocks acquired),
1647 * errno on failure (no glocks acquired)
1648 */
1649
1650static int nq_m_sync(unsigned int num_gh, struct gfs2_holder *ghs,
1651 struct gfs2_holder **p)
1652{
1653 unsigned int x;
1654 int error = 0;
1655
1656 for (x = 0; x < num_gh; x++)
1657 p[x] = &ghs[x];
1658
1659 sort(p, num_gh, sizeof(struct gfs2_holder *), glock_compare, NULL);
1660
1661 for (x = 0; x < num_gh; x++) {
1662 p[x]->gh_flags &= ~(LM_FLAG_TRY | GL_ASYNC);
1663
1664 error = gfs2_glock_nq(p[x]);
1665 if (error) {
1666 while (x--)
1667 gfs2_glock_dq(p[x]);
1668 break;
1669 }
1670 }
1671
1672 return error;
1673}
1674
1675/**
1676 * gfs2_glock_nq_m - acquire multiple glocks
1677 * @num_gh: the number of structures
1678 * @ghs: an array of struct gfs2_holder structures
1679 *
1680 * Figure out how big an impact this function has. Either:
1681 * 1) Replace this code with code that calls gfs2_glock_prefetch()
1682 * 2) Forget async stuff and just call nq_m_sync()
1683 * 3) Leave it like it is
1684 *
1685 * Returns: 0 on success (all glocks acquired),
1686 * errno on failure (no glocks acquired)
1687 */
1688
1689int gfs2_glock_nq_m(unsigned int num_gh, struct gfs2_holder *ghs)
1690{
1691 int *e;
1692 unsigned int x;
1693 int borked = 0, serious = 0;
1694 int error = 0;
1695
1696 if (!num_gh)
1697 return 0;
1698
1699 if (num_gh == 1) {
1700 ghs->gh_flags &= ~(LM_FLAG_TRY | GL_ASYNC);
1701 return gfs2_glock_nq(ghs);
1702 }
1703
1704 e = kcalloc(num_gh, sizeof(struct gfs2_holder *), GFP_KERNEL);
1705 if (!e)
1706 return -ENOMEM;
1707
1708 for (x = 0; x < num_gh; x++) {
1709 ghs[x].gh_flags |= LM_FLAG_TRY | GL_ASYNC;
1710 error = gfs2_glock_nq(&ghs[x]);
1711 if (error) {
1712 borked = 1;
1713 serious = error;
1714 num_gh = x;
1715 break;
1716 }
1717 }
1718
1719 for (x = 0; x < num_gh; x++) {
1720 error = e[x] = glock_wait_internal(&ghs[x]);
1721 if (error) {
1722 borked = 1;
1723 if (error != GLR_TRYFAILED && error != GLR_CANCELED)
1724 serious = error;
1725 }
1726 }
1727
1728 if (!borked) {
1729 kfree(e);
1730 return 0;
1731 }
1732
1733 for (x = 0; x < num_gh; x++)
1734 if (!e[x])
1735 gfs2_glock_dq(&ghs[x]);
1736
1737 if (serious)
1738 error = serious;
1739 else {
1740 for (x = 0; x < num_gh; x++)
1741 gfs2_holder_reinit(ghs[x].gh_state, ghs[x].gh_flags,
1742 &ghs[x]);
1743 error = nq_m_sync(num_gh, ghs, (struct gfs2_holder **)e);
1744 }
1745
1746 kfree(e);
1747
1748 return error;
1749}
1750
1751/**
1752 * gfs2_glock_dq_m - release multiple glocks
1753 * @num_gh: the number of structures
1754 * @ghs: an array of struct gfs2_holder structures
1755 *
1756 */
1757
1758void gfs2_glock_dq_m(unsigned int num_gh, struct gfs2_holder *ghs)
1759{
1760 unsigned int x;
1761
1762 for (x = 0; x < num_gh; x++)
1763 gfs2_glock_dq(&ghs[x]);
1764}
1765
1766/**
1767 * gfs2_glock_dq_uninit_m - release multiple glocks
1768 * @num_gh: the number of structures
1769 * @ghs: an array of struct gfs2_holder structures
1770 *
1771 */
1772
1773void gfs2_glock_dq_uninit_m(unsigned int num_gh, struct gfs2_holder *ghs)
1774{
1775 unsigned int x;
1776
1777 for (x = 0; x < num_gh; x++)
1778 gfs2_glock_dq_uninit(&ghs[x]);
1779}
1780
1781/**
1782 * gfs2_glock_prefetch_num - prefetch a glock based on lock number
1783 * @sdp: the filesystem
1784 * @number: the lock number
1785 * @glops: the glock operations for the type of glock
1786 * @state: the state to acquire the glock in
1787 * @flags: modifier flags for the aquisition
1788 *
1789 * Returns: errno
1790 */
1791
1792void gfs2_glock_prefetch_num(struct gfs2_sbd *sdp, uint64_t number,
1793 struct gfs2_glock_operations *glops,
1794 unsigned int state, int flags)
1795{
1796 struct gfs2_glock *gl;
1797 int error;
1798
1799 if (atomic_read(&sdp->sd_reclaim_count) <
1800 gfs2_tune_get(sdp, gt_reclaim_limit)) {
1801 error = gfs2_glock_get(sdp, number, glops, CREATE, &gl);
1802 if (!error) {
1803 gfs2_glock_prefetch(gl, state, flags);
1804 gfs2_glock_put(gl);
1805 }
1806 }
1807}
1808
1809/**
1810 * gfs2_lvb_hold - attach a LVB from a glock
1811 * @gl: The glock in question
1812 *
1813 */
1814
1815int gfs2_lvb_hold(struct gfs2_glock *gl)
1816{
1817 int error;
1818
1819 gfs2_glmutex_lock(gl);
1820
1821 if (!atomic_read(&gl->gl_lvb_count)) {
1822 error = gfs2_lm_hold_lvb(gl->gl_sbd, gl->gl_lock, &gl->gl_lvb);
1823 if (error) {
1824 gfs2_glmutex_unlock(gl);
1825 return error;
1826 }
1827 gfs2_glock_hold(gl);
1828 }
1829 atomic_inc(&gl->gl_lvb_count);
1830
1831 gfs2_glmutex_unlock(gl);
1832
1833 return 0;
1834}
1835
1836/**
1837 * gfs2_lvb_unhold - detach a LVB from a glock
1838 * @gl: The glock in question
1839 *
1840 */
1841
1842void gfs2_lvb_unhold(struct gfs2_glock *gl)
1843{
1844 gfs2_glock_hold(gl);
1845 gfs2_glmutex_lock(gl);
1846
1847 gfs2_assert(gl->gl_sbd, atomic_read(&gl->gl_lvb_count) > 0);
1848 if (atomic_dec_and_test(&gl->gl_lvb_count)) {
1849 gfs2_lm_unhold_lvb(gl->gl_sbd, gl->gl_lock, gl->gl_lvb);
1850 gl->gl_lvb = NULL;
1851 gfs2_glock_put(gl);
1852 }
1853
1854 gfs2_glmutex_unlock(gl);
1855 gfs2_glock_put(gl);
1856}
1857
1858void gfs2_lvb_sync(struct gfs2_glock *gl)
1859{
1860 gfs2_glmutex_lock(gl);
1861
1862 gfs2_assert(gl->gl_sbd, atomic_read(&gl->gl_lvb_count));
1863 if (!gfs2_assert_warn(gl->gl_sbd, gfs2_glock_is_held_excl(gl)))
1864 gfs2_lm_sync_lvb(gl->gl_sbd, gl->gl_lock, gl->gl_lvb);
1865
1866 gfs2_glmutex_unlock(gl);
1867}
1868
1869static void blocking_cb(struct gfs2_sbd *sdp, struct lm_lockname *name,
1870 unsigned int state)
1871{
1872 struct gfs2_glock *gl;
1873
1874 gl = gfs2_glock_find(sdp, name);
1875 if (!gl)
1876 return;
1877
1878 if (gl->gl_ops->go_callback)
1879 gl->gl_ops->go_callback(gl, state);
1880 handle_callback(gl, state);
1881
1882 spin_lock(&gl->gl_spin);
1883 run_queue(gl);
1884 spin_unlock(&gl->gl_spin);
1885
1886 gfs2_glock_put(gl);
1887}
1888
1889/**
1890 * gfs2_glock_cb - Callback used by locking module
1891 * @fsdata: Pointer to the superblock
1892 * @type: Type of callback
1893 * @data: Type dependent data pointer
1894 *
1895 * Called by the locking module when it wants to tell us something.
1896 * Either we need to drop a lock, one of our ASYNC requests completed, or
1897 * a journal from another client needs to be recovered.
1898 */
1899
1900void gfs2_glock_cb(lm_fsdata_t *fsdata, unsigned int type, void *data)
1901{
1902 struct gfs2_sbd *sdp = (struct gfs2_sbd *)fsdata;
1903
b3b94faa
DT		 1904 switch (type) {
1905 case LM_CB_NEED_E:
1906 blocking_cb(sdp, (struct lm_lockname *)data, LM_ST_UNLOCKED);
1907 return;
1908
1909 case LM_CB_NEED_D:
1910 blocking_cb(sdp, (struct lm_lockname *)data, LM_ST_DEFERRED);
1911 return;
1912
1913 case LM_CB_NEED_S:
1914 blocking_cb(sdp, (struct lm_lockname *)data, LM_ST_SHARED);
1915 return;
1916
1917 case LM_CB_ASYNC: {
1918 struct lm_async_cb *async = (struct lm_async_cb *)data;
1919 struct gfs2_glock *gl;
1920
1921 gl = gfs2_glock_find(sdp, &async->lc_name);
1922 if (gfs2_assert_warn(sdp, gl))
1923 return;
1924 if (!gfs2_assert_warn(sdp, gl->gl_req_bh))
1925 gl->gl_req_bh(gl, async->lc_ret);
1926 gfs2_glock_put(gl);
1927
1928 return;
1929 }
1930
1931 case LM_CB_NEED_RECOVERY:
1932 gfs2_jdesc_make_dirty(sdp, *(unsigned int *)data);
1933 if (sdp->sd_recoverd_process)
1934 wake_up_process(sdp->sd_recoverd_process);
1935 return;
1936
1937 case LM_CB_DROPLOCKS:
1938 gfs2_gl_hash_clear(sdp, NO_WAIT);
1939 gfs2_quota_scan(sdp);
1940 return;
1941
1942 default:
1943 gfs2_assert_warn(sdp, 0);
1944 return;
1945 }
1946}
1947
1948/**
1949 * gfs2_try_toss_inode - try to remove a particular inode struct from cache
1950 * sdp: the filesystem
1951 * inum: the inode number
1952 *
1953 */
1954
1955void gfs2_try_toss_inode(struct gfs2_sbd *sdp, struct gfs2_inum *inum)
1956{
1957 struct gfs2_glock *gl;
1958 struct gfs2_inode *ip;
1959 int error;
1960
1961 error = gfs2_glock_get(sdp, inum->no_addr, &gfs2_inode_glops,
1962 NO_CREATE, &gl);
1963 if (error || !gl)
1964 return;
1965
1966 if (!gfs2_glmutex_trylock(gl))
1967 goto out;
1968
5c676f6d 1969 ip = gl->gl_object;
b3b94faa
DT		 1970 if (!ip)
1971 goto out_unlock;
1972
1973 if (atomic_read(&ip->i_count))
1974 goto out_unlock;
1975
1976 gfs2_inode_destroy(ip);
1977
1978 out_unlock:
1979 gfs2_glmutex_unlock(gl);
1980
1981 out:
1982 gfs2_glock_put(gl);
1983}
1984
1985/**
1986 * gfs2_iopen_go_callback - Try to kick the inode/vnode associated with an
1987 * iopen glock from memory
1988 * @io_gl: the iopen glock
1989 * @state: the state into which the glock should be put
1990 *
1991 */
1992
1993void gfs2_iopen_go_callback(struct gfs2_glock *io_gl, unsigned int state)
1994{
1995 struct gfs2_glock *i_gl;
1996
1997 if (state != LM_ST_UNLOCKED)
1998 return;
1999
2000 spin_lock(&io_gl->gl_spin);
5c676f6d 2001 i_gl = io_gl->gl_object;
b3b94faa
DT		 2002 if (i_gl) {
2003 gfs2_glock_hold(i_gl);
2004 spin_unlock(&io_gl->gl_spin);
2005 } else {
2006 spin_unlock(&io_gl->gl_spin);
2007 return;
2008 }
2009
2010 if (gfs2_glmutex_trylock(i_gl)) {
5c676f6d 2011 struct gfs2_inode *ip = i_gl->gl_object;
b3b94faa
DT		 2012 if (ip) {
2013 gfs2_try_toss_vnode(ip);
2014 gfs2_glmutex_unlock(i_gl);
2015 gfs2_glock_schedule_for_reclaim(i_gl);
2016 goto out;
2017 }
2018 gfs2_glmutex_unlock(i_gl);
2019 }
2020
2021 out:
2022 gfs2_glock_put(i_gl);
2023}
2024
2025/**
2026 * demote_ok - Check to see if it's ok to unlock a glock
2027 * @gl: the glock
2028 *
2029 * Returns: 1 if it's ok
2030 */
2031
2032static int demote_ok(struct gfs2_glock *gl)
2033{
2034 struct gfs2_sbd *sdp = gl->gl_sbd;
2035 struct gfs2_glock_operations *glops = gl->gl_ops;
2036 int demote = 1;
2037
2038 if (test_bit(GLF_STICKY, &gl->gl_flags))
2039 demote = 0;
2040 else if (test_bit(GLF_PREFETCH, &gl->gl_flags))
2041 demote = time_after_eq(jiffies,
2042 gl->gl_stamp +
2043 gfs2_tune_get(sdp, gt_prefetch_secs) * HZ);
2044 else if (glops->go_demote_ok)
2045 demote = glops->go_demote_ok(gl);
2046
2047 return demote;
2048}
2049
2050/**
2051 * gfs2_glock_schedule_for_reclaim - Add a glock to the reclaim list
2052 * @gl: the glock
2053 *
2054 */
2055
2056void gfs2_glock_schedule_for_reclaim(struct gfs2_glock *gl)
2057{
2058 struct gfs2_sbd *sdp = gl->gl_sbd;
2059
2060 spin_lock(&sdp->sd_reclaim_lock);
2061 if (list_empty(&gl->gl_reclaim)) {
2062 gfs2_glock_hold(gl);
2063 list_add(&gl->gl_reclaim, &sdp->sd_reclaim_list);
2064 atomic_inc(&sdp->sd_reclaim_count);
2065 }
2066 spin_unlock(&sdp->sd_reclaim_lock);
2067
2068 wake_up(&sdp->sd_reclaim_wq);
2069}
2070
2071/**
2072 * gfs2_reclaim_glock - process the next glock on the filesystem's reclaim list
2073 * @sdp: the filesystem
2074 *
2075 * Called from gfs2_glockd() glock reclaim daemon, or when promoting a
2076 * different glock and we notice that there are a lot of glocks in the
2077 * reclaim list.
2078 *
2079 */
2080
2081void gfs2_reclaim_glock(struct gfs2_sbd *sdp)
2082{
2083 struct gfs2_glock *gl;
2084
2085 spin_lock(&sdp->sd_reclaim_lock);
2086 if (list_empty(&sdp->sd_reclaim_list)) {
2087 spin_unlock(&sdp->sd_reclaim_lock);
2088 return;
2089 }
2090 gl = list_entry(sdp->sd_reclaim_list.next,
2091 struct gfs2_glock, gl_reclaim);
2092 list_del_init(&gl->gl_reclaim);
2093 spin_unlock(&sdp->sd_reclaim_lock);
2094
2095 atomic_dec(&sdp->sd_reclaim_count);
2096 atomic_inc(&sdp->sd_reclaimed);
2097
2098 if (gfs2_glmutex_trylock(gl)) {
2099 if (gl->gl_ops == &gfs2_inode_glops) {
5c676f6d 2100 struct gfs2_inode *ip = gl->gl_object;
b3b94faa
DT		 2101 if (ip && !atomic_read(&ip->i_count))
2102 gfs2_inode_destroy(ip);
2103 }
2104 if (queue_empty(gl, &gl->gl_holders) &&
2105 gl->gl_state != LM_ST_UNLOCKED &&
2106 demote_ok(gl))
2107 handle_callback(gl, LM_ST_UNLOCKED);
2108 gfs2_glmutex_unlock(gl);
2109 }
2110
2111 gfs2_glock_put(gl);
2112}
2113
2114/**
2115 * examine_bucket - Call a function for glock in a hash bucket
2116 * @examiner: the function
2117 * @sdp: the filesystem
2118 * @bucket: the bucket
2119 *
2120 * Returns: 1 if the bucket has entries
2121 */
2122
2123static int examine_bucket(glock_examiner examiner, struct gfs2_sbd *sdp,
2124 struct gfs2_gl_hash_bucket *bucket)
2125{
2126 struct glock_plug plug;
2127 struct list_head *tmp;
2128 struct gfs2_glock *gl;
2129 int entries;
2130
2131 /* Add "plug" to end of bucket list, work back up list from there */
2132 memset(&plug.gl_flags, 0, sizeof(unsigned long));
2133 set_bit(GLF_PLUG, &plug.gl_flags);
2134
2135 write_lock(&bucket->hb_lock);
2136 list_add(&plug.gl_list, &bucket->hb_list);
2137 write_unlock(&bucket->hb_lock);
2138
2139 for (;;) {
2140 write_lock(&bucket->hb_lock);
2141
2142 for (;;) {
2143 tmp = plug.gl_list.next;
2144
2145 if (tmp == &bucket->hb_list) {
2146 list_del(&plug.gl_list);
2147 entries = !list_empty(&bucket->hb_list);
2148 write_unlock(&bucket->hb_lock);
2149 return entries;
2150 }
2151 gl = list_entry(tmp, struct gfs2_glock, gl_list);
2152
2153 /* Move plug up list */
2154 list_move(&plug.gl_list, &gl->gl_list);
2155
2156 if (test_bit(GLF_PLUG, &gl->gl_flags))
2157 continue;
2158
2159 /* examiner() must glock_put() */
2160 gfs2_glock_hold(gl);
2161
2162 break;
2163 }
2164
2165 write_unlock(&bucket->hb_lock);
2166
2167 examiner(gl);
2168 }
2169}
2170
2171/**
2172 * scan_glock - look at a glock and see if we can reclaim it
2173 * @gl: the glock to look at
2174 *
2175 */
2176
2177static void scan_glock(struct gfs2_glock *gl)
2178{
2179 if (gfs2_glmutex_trylock(gl)) {
2180 if (gl->gl_ops == &gfs2_inode_glops) {
5c676f6d 2181 struct gfs2_inode *ip = gl->gl_object;
b3b94faa
DT		 2182 if (ip && !atomic_read(&ip->i_count))
2183 goto out_schedule;
2184 }
2185 if (queue_empty(gl, &gl->gl_holders) &&
2186 gl->gl_state != LM_ST_UNLOCKED &&
2187 demote_ok(gl))
2188 goto out_schedule;
2189
2190 gfs2_glmutex_unlock(gl);
2191 }
2192
2193 gfs2_glock_put(gl);
2194
2195 return;
2196
2197 out_schedule:
2198 gfs2_glmutex_unlock(gl);
2199 gfs2_glock_schedule_for_reclaim(gl);
2200 gfs2_glock_put(gl);
2201}
2202
2203/**
2204 * gfs2_scand_internal - Look for glocks and inodes to toss from memory
2205 * @sdp: the filesystem
2206 *
2207 */
2208
2209void gfs2_scand_internal(struct gfs2_sbd *sdp)
2210{
2211 unsigned int x;
2212
2213 for (x = 0; x < GFS2_GL_HASH_SIZE; x++) {
2214 examine_bucket(scan_glock, sdp, &sdp->sd_gl_hash[x]);
2215 cond_resched();
2216 }
2217}
2218
2219/**
2220 * clear_glock - look at a glock and see if we can free it from glock cache
2221 * @gl: the glock to look at
2222 *
2223 */
2224
2225static void clear_glock(struct gfs2_glock *gl)
2226{
2227 struct gfs2_sbd *sdp = gl->gl_sbd;
2228 int released;
2229
2230 spin_lock(&sdp->sd_reclaim_lock);
2231 if (!list_empty(&gl->gl_reclaim)) {
2232 list_del_init(&gl->gl_reclaim);
2233 atomic_dec(&sdp->sd_reclaim_count);
2234 released = gfs2_glock_put(gl);
2235 gfs2_assert(sdp, !released);
2236 }
2237 spin_unlock(&sdp->sd_reclaim_lock);
2238
2239 if (gfs2_glmutex_trylock(gl)) {
2240 if (gl->gl_ops == &gfs2_inode_glops) {
5c676f6d 2241 struct gfs2_inode *ip = gl->gl_object;
b3b94faa
DT		 2242 if (ip && !atomic_read(&ip->i_count))
2243 gfs2_inode_destroy(ip);
2244 }
2245 if (queue_empty(gl, &gl->gl_holders) &&
2246 gl->gl_state != LM_ST_UNLOCKED)
2247 handle_callback(gl, LM_ST_UNLOCKED);
2248
2249 gfs2_glmutex_unlock(gl);
2250 }
2251
2252 gfs2_glock_put(gl);
2253}
2254
2255/**
2256 * gfs2_gl_hash_clear - Empty out the glock hash table
2257 * @sdp: the filesystem
2258 * @wait: wait until it's all gone
2259 *
2260 * Called when unmounting the filesystem, or when inter-node lock manager
2261 * requests DROPLOCKS because it is running out of capacity.
2262 */
2263
2264void gfs2_gl_hash_clear(struct gfs2_sbd *sdp, int wait)
2265{
2266 unsigned long t;
2267 unsigned int x;
2268 int cont;
2269
2270 t = jiffies;
2271
2272 for (;;) {
2273 cont = 0;
2274
2275 for (x = 0; x < GFS2_GL_HASH_SIZE; x++)
2276 if (examine_bucket(clear_glock, sdp,
2277 &sdp->sd_gl_hash[x]))
2278 cont = 1;
2279
2280 if (!wait || !cont)
2281 break;
2282
2283 if (time_after_eq(jiffies,
2284 t + gfs2_tune_get(sdp, gt_stall_secs) * HZ)) {
2285 fs_warn(sdp, "Unmount seems to be stalled. "
2286 "Dumping lock state...\n");
2287 gfs2_dump_lockstate(sdp);
2288 t = jiffies;
2289 }
2290
2291 /* invalidate_inodes() requires that the sb inodes list
2292 not change, but an async completion callback for an
2293 unlock can occur which does glock_put() which
2294 can call iput() which will change the sb inodes list.
2295 invalidate_inodes_mutex prevents glock_put()'s during
2296 an invalidate_inodes() */
2297
f55ab26a 2298 mutex_lock(&sdp->sd_invalidate_inodes_mutex);
b3b94faa 2299 invalidate_inodes(sdp->sd_vfs);
f55ab26a 2300 mutex_unlock(&sdp->sd_invalidate_inodes_mutex);
b3b94faa
DT		 2301 yield();
2302 }
2303}
2304
2305/*
2306 * Diagnostic routines to help debug distributed deadlock
2307 */
2308
2309/**
2310 * dump_holder - print information about a glock holder
2311 * @str: a string naming the type of holder
2312 * @gh: the glock holder
2313 *
2314 * Returns: 0 on success, -ENOBUFS when we run out of space
2315 */
2316
2317static int dump_holder(char *str, struct gfs2_holder *gh)
2318{
2319 unsigned int x;
2320 int error = -ENOBUFS;
2321
d92a8d48
SW		 2322 printk(KERN_INFO " %s\n", str);
2323 printk(KERN_INFO " owner = %ld\n",
b3b94faa 2324 (gh->gh_owner) ? (long)gh->gh_owner->pid : -1);
d92a8d48
SW		 2325 printk(KERN_INFO " gh_state = %u\n", gh->gh_state);
2326 printk(KERN_INFO " gh_flags =");
b3b94faa
DT		 2327 for (x = 0; x < 32; x++)
2328 if (gh->gh_flags & (1 << x))
2329 printk(" %u", x);
2330 printk(" \n");
d92a8d48
SW		 2331 printk(KERN_INFO " error = %d\n", gh->gh_error);
2332 printk(KERN_INFO " gh_iflags =");
b3b94faa
DT		 2333 for (x = 0; x < 32; x++)
2334 if (test_bit(x, &gh->gh_iflags))
2335 printk(" %u", x);
2336 printk(" \n");
2337
2338 error = 0;
2339
2340 return error;
2341}
2342
2343/**
2344 * dump_inode - print information about an inode
2345 * @ip: the inode
2346 *
2347 * Returns: 0 on success, -ENOBUFS when we run out of space
2348 */
2349
2350static int dump_inode(struct gfs2_inode *ip)
2351{
2352 unsigned int x;
2353 int error = -ENOBUFS;
2354
d92a8d48
SW		 2355 printk(KERN_INFO " Inode:\n");
2356 printk(KERN_INFO " num = %llu %llu\n",
b3b94faa 2357 ip->i_num.no_formal_ino, ip->i_num.no_addr);
d92a8d48
SW		 2358 printk(KERN_INFO " type = %u\n", IF2DT(ip->i_di.di_mode));
2359 printk(KERN_INFO " i_count = %d\n", atomic_read(&ip->i_count));
2360 printk(KERN_INFO " i_flags =");
b3b94faa
DT		 2361 for (x = 0; x < 32; x++)
2362 if (test_bit(x, &ip->i_flags))
2363 printk(" %u", x);
2364 printk(" \n");
d92a8d48 2365 printk(KERN_INFO " vnode = %s\n", (ip->i_vnode) ? "yes" : "no");
b3b94faa
DT		 2366
2367 error = 0;
2368
2369 return error;
2370}
2371
2372/**
2373 * dump_glock - print information about a glock
2374 * @gl: the glock
2375 * @count: where we are in the buffer
2376 *
2377 * Returns: 0 on success, -ENOBUFS when we run out of space
2378 */
2379
2380static int dump_glock(struct gfs2_glock *gl)
2381{
2382 struct gfs2_holder *gh;
2383 unsigned int x;
2384 int error = -ENOBUFS;
2385
2386 spin_lock(&gl->gl_spin);
2387
d92a8d48 2388 printk(KERN_INFO "Glock (%u, %llu)\n",
b3b94faa
DT		 2389 gl->gl_name.ln_type,
2390 gl->gl_name.ln_number);
d92a8d48 2391 printk(KERN_INFO " gl_flags =");
b3b94faa
DT		 2392 for (x = 0; x < 32; x++)
2393 if (test_bit(x, &gl->gl_flags))
2394 printk(" %u", x);
2395 printk(" \n");
d92a8d48
SW		 2396 printk(KERN_INFO " gl_ref = %d\n", atomic_read(&gl->gl_ref.refcount));
2397 printk(KERN_INFO " gl_state = %u\n", gl->gl_state);
2398 printk(KERN_INFO " req_gh = %s\n", (gl->gl_req_gh) ? "yes" : "no");
2399 printk(KERN_INFO " req_bh = %s\n", (gl->gl_req_bh) ? "yes" : "no");
2400 printk(KERN_INFO " lvb_count = %d\n", atomic_read(&gl->gl_lvb_count));
2401 printk(KERN_INFO " object = %s\n", (gl->gl_object) ? "yes" : "no");
2402 printk(KERN_INFO " le = %s\n",
b3b94faa 2403 (list_empty(&gl->gl_le.le_list)) ? "no" : "yes");
d92a8d48 2404 printk(KERN_INFO " reclaim = %s\n",
b3b94faa
DT		 2405 (list_empty(&gl->gl_reclaim)) ? "no" : "yes");
2406 if (gl->gl_aspace)
d92a8d48 2407 printk(KERN_INFO " aspace = %lu\n",
b3b94faa
DT		 2408 gl->gl_aspace->i_mapping->nrpages);
2409 else
d92a8d48
SW		 2410 printk(KERN_INFO " aspace = no\n");
2411 printk(KERN_INFO " ail = %d\n", atomic_read(&gl->gl_ail_count));
b3b94faa
DT		 2412 if (gl->gl_req_gh) {
2413 error = dump_holder("Request", gl->gl_req_gh);
2414 if (error)
2415 goto out;
2416 }
2417 list_for_each_entry(gh, &gl->gl_holders, gh_list) {
2418 error = dump_holder("Holder", gh);
2419 if (error)
2420 goto out;
2421 }
2422 list_for_each_entry(gh, &gl->gl_waiters1, gh_list) {
2423 error = dump_holder("Waiter1", gh);
2424 if (error)
2425 goto out;
2426 }
2427 list_for_each_entry(gh, &gl->gl_waiters2, gh_list) {
2428 error = dump_holder("Waiter2", gh);
2429 if (error)
2430 goto out;
2431 }
2432 list_for_each_entry(gh, &gl->gl_waiters3, gh_list) {
2433 error = dump_holder("Waiter3", gh);
2434 if (error)
2435 goto out;
2436 }
5c676f6d 2437 if (gl->gl_ops == &gfs2_inode_glops && gl->gl_object) {
b3b94faa
DT		 2438 if (!test_bit(GLF_LOCK, &gl->gl_flags) &&
2439 list_empty(&gl->gl_holders)) {
5c676f6d 2440 error = dump_inode(gl->gl_object);
b3b94faa
DT		 2441 if (error)
2442 goto out;
2443 } else {
2444 error = -ENOBUFS;
d92a8d48 2445 printk(KERN_INFO " Inode: busy\n");
b3b94faa
DT		 2446 }
2447 }
2448
2449 error = 0;
2450
2451 out:
2452 spin_unlock(&gl->gl_spin);
2453
2454 return error;
2455}
2456
2457/**
2458 * gfs2_dump_lockstate - print out the current lockstate
2459 * @sdp: the filesystem
2460 * @ub: the buffer to copy the information into
2461 *
2462 * If @ub is NULL, dump the lockstate to the console.
2463 *
2464 */
2465
2466int gfs2_dump_lockstate(struct gfs2_sbd *sdp)
2467{
2468 struct gfs2_gl_hash_bucket *bucket;
2469 struct gfs2_glock *gl;
2470 unsigned int x;
2471 int error = 0;
2472
2473 for (x = 0; x < GFS2_GL_HASH_SIZE; x++) {
2474 bucket = &sdp->sd_gl_hash[x];
2475
2476 read_lock(&bucket->hb_lock);
2477
2478 list_for_each_entry(gl, &bucket->hb_list, gl_list) {
2479 if (test_bit(GLF_PLUG, &gl->gl_flags))
2480 continue;
2481
2482 error = dump_glock(gl);
2483 if (error)
2484 break;
2485 }
2486
2487 read_unlock(&bucket->hb_lock);
2488
2489 if (error)
2490 break;
2491 }
2492
2493
2494 return error;
2495}
2496
kernel source for telekom puls (alcatel/mediatek)