blob: 17d474fab5ab26c2848cf84b06baa255c6e6980a [file] [log] [blame]
David Teiglandb3b94fa2006-01-16 16:50:04 +00001/*
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>
Steven Whitehoused0dc80d2006-03-29 14:36:49 -050019#include <linux/kallsyms.h>
Steven Whitehouse5c676f62006-02-27 17:23:27 -050020#include <linux/gfs2_ondisk.h>
David Teiglandb3b94fa2006-01-16 16:50:04 +000021#include <asm/semaphore.h>
22#include <asm/uaccess.h>
23
24#include "gfs2.h"
Steven Whitehouse5c676f62006-02-27 17:23:27 -050025#include "lm_interface.h"
26#include "incore.h"
David Teiglandb3b94fa2006-01-16 16:50:04 +000027#include "glock.h"
28#include "glops.h"
29#include "inode.h"
30#include "lm.h"
31#include "lops.h"
32#include "meta_io.h"
33#include "quota.h"
34#include "super.h"
Steven Whitehouse5c676f62006-02-27 17:23:27 -050035#include "util.h"
David Teiglandb3b94fa2006-01-16 16:50:04 +000036
37/* Must be kept in sync with the beginning of struct gfs2_glock */
38struct glock_plug {
39 struct list_head gl_list;
40 unsigned long gl_flags;
41};
42
43struct greedy {
44 struct gfs2_holder gr_gh;
45 struct work_struct gr_work;
46};
47
48typedef void (*glock_examiner) (struct gfs2_glock * gl);
49
50/**
51 * relaxed_state_ok - is a requested lock compatible with the current lock mode?
52 * @actual: the current state of the lock
53 * @requested: the lock state that was requested by the caller
54 * @flags: the modifier flags passed in by the caller
55 *
56 * Returns: 1 if the locks are compatible, 0 otherwise
57 */
58
59static inline int relaxed_state_ok(unsigned int actual, unsigned requested,
60 int flags)
61{
62 if (actual == requested)
63 return 1;
64
65 if (flags & GL_EXACT)
66 return 0;
67
68 if (actual == LM_ST_EXCLUSIVE && requested == LM_ST_SHARED)
69 return 1;
70
71 if (actual != LM_ST_UNLOCKED && (flags & LM_FLAG_ANY))
72 return 1;
73
74 return 0;
75}
76
77/**
78 * gl_hash() - Turn glock number into hash bucket number
79 * @lock: The glock number
80 *
81 * Returns: The number of the corresponding hash bucket
82 */
83
84static unsigned int gl_hash(struct lm_lockname *name)
85{
86 unsigned int h;
87
88 h = jhash(&name->ln_number, sizeof(uint64_t), 0);
89 h = jhash(&name->ln_type, sizeof(unsigned int), h);
90 h &= GFS2_GL_HASH_MASK;
91
92 return h;
93}
94
95/**
96 * glock_free() - Perform a few checks and then release struct gfs2_glock
97 * @gl: The glock to release
98 *
99 * Also calls lock module to release its internal structure for this glock.
100 *
101 */
102
103static void glock_free(struct gfs2_glock *gl)
104{
105 struct gfs2_sbd *sdp = gl->gl_sbd;
106 struct inode *aspace = gl->gl_aspace;
107
108 gfs2_lm_put_lock(sdp, gl->gl_lock);
109
110 if (aspace)
111 gfs2_aspace_put(aspace);
112
113 kmem_cache_free(gfs2_glock_cachep, gl);
David Teiglandb3b94fa2006-01-16 16:50:04 +0000114}
115
116/**
117 * gfs2_glock_hold() - increment reference count on glock
118 * @gl: The glock to hold
119 *
120 */
121
122void gfs2_glock_hold(struct gfs2_glock *gl)
123{
124 kref_get(&gl->gl_ref);
125}
126
127/* All work is done after the return from kref_put() so we
128 can release the write_lock before the free. */
129
130static void kill_glock(struct kref *kref)
131{
132 struct gfs2_glock *gl = container_of(kref, struct gfs2_glock, gl_ref);
133 struct gfs2_sbd *sdp = gl->gl_sbd;
134
135 gfs2_assert(sdp, gl->gl_state == LM_ST_UNLOCKED);
136 gfs2_assert(sdp, list_empty(&gl->gl_reclaim));
137 gfs2_assert(sdp, list_empty(&gl->gl_holders));
138 gfs2_assert(sdp, list_empty(&gl->gl_waiters1));
139 gfs2_assert(sdp, list_empty(&gl->gl_waiters2));
140 gfs2_assert(sdp, list_empty(&gl->gl_waiters3));
141}
142
143/**
144 * gfs2_glock_put() - Decrement reference count on glock
145 * @gl: The glock to put
146 *
147 */
148
149int gfs2_glock_put(struct gfs2_glock *gl)
150{
151 struct gfs2_sbd *sdp = gl->gl_sbd;
152 struct gfs2_gl_hash_bucket *bucket = gl->gl_bucket;
153 int rv = 0;
154
Steven Whitehousef55ab262006-02-21 12:51:39 +0000155 mutex_lock(&sdp->sd_invalidate_inodes_mutex);
David Teiglandb3b94fa2006-01-16 16:50:04 +0000156
157 write_lock(&bucket->hb_lock);
158 if (kref_put(&gl->gl_ref, kill_glock)) {
159 list_del_init(&gl->gl_list);
160 write_unlock(&bucket->hb_lock);
Steven Whitehouse190562b2006-04-20 16:57:23 -0400161 BUG_ON(spin_is_locked(&gl->gl_spin));
David Teiglandb3b94fa2006-01-16 16:50:04 +0000162 glock_free(gl);
163 rv = 1;
164 goto out;
165 }
166 write_unlock(&bucket->hb_lock);
167 out:
Steven Whitehousef55ab262006-02-21 12:51:39 +0000168 mutex_unlock(&sdp->sd_invalidate_inodes_mutex);
David Teiglandb3b94fa2006-01-16 16:50:04 +0000169 return rv;
170}
171
172/**
173 * queue_empty - check to see if a glock's queue is empty
174 * @gl: the glock
175 * @head: the head of the queue to check
176 *
177 * This function protects the list in the event that a process already
178 * has a holder on the list and is adding a second holder for itself.
179 * The glmutex lock is what generally prevents processes from working
180 * on the same glock at once, but the special case of adding a second
181 * holder for yourself ("recursive" locking) doesn't involve locking
182 * glmutex, making the spin lock necessary.
183 *
184 * Returns: 1 if the queue is empty
185 */
186
187static inline int queue_empty(struct gfs2_glock *gl, struct list_head *head)
188{
189 int empty;
190 spin_lock(&gl->gl_spin);
191 empty = list_empty(head);
192 spin_unlock(&gl->gl_spin);
193 return empty;
194}
195
196/**
197 * search_bucket() - Find struct gfs2_glock by lock number
198 * @bucket: the bucket to search
199 * @name: The lock name
200 *
201 * Returns: NULL, or the struct gfs2_glock with the requested number
202 */
203
204static struct gfs2_glock *search_bucket(struct gfs2_gl_hash_bucket *bucket,
205 struct lm_lockname *name)
206{
207 struct gfs2_glock *gl;
208
209 list_for_each_entry(gl, &bucket->hb_list, gl_list) {
210 if (test_bit(GLF_PLUG, &gl->gl_flags))
211 continue;
212 if (!lm_name_equal(&gl->gl_name, name))
213 continue;
214
215 kref_get(&gl->gl_ref);
216
217 return gl;
218 }
219
220 return NULL;
221}
222
223/**
224 * gfs2_glock_find() - Find glock by lock number
225 * @sdp: The GFS2 superblock
226 * @name: The lock name
227 *
228 * Returns: NULL, or the struct gfs2_glock with the requested number
229 */
230
231struct gfs2_glock *gfs2_glock_find(struct gfs2_sbd *sdp,
232 struct lm_lockname *name)
233{
234 struct gfs2_gl_hash_bucket *bucket = &sdp->sd_gl_hash[gl_hash(name)];
235 struct gfs2_glock *gl;
236
237 read_lock(&bucket->hb_lock);
238 gl = search_bucket(bucket, name);
239 read_unlock(&bucket->hb_lock);
240
241 return gl;
242}
243
244/**
245 * gfs2_glock_get() - Get a glock, or create one if one doesn't exist
246 * @sdp: The GFS2 superblock
247 * @number: the lock number
248 * @glops: The glock_operations to use
249 * @create: If 0, don't create the glock if it doesn't exist
250 * @glp: the glock is returned here
251 *
252 * This does not lock a glock, just finds/creates structures for one.
253 *
254 * Returns: errno
255 */
256
257int gfs2_glock_get(struct gfs2_sbd *sdp, uint64_t number,
258 struct gfs2_glock_operations *glops, int create,
259 struct gfs2_glock **glp)
260{
261 struct lm_lockname name;
262 struct gfs2_glock *gl, *tmp;
263 struct gfs2_gl_hash_bucket *bucket;
264 int error;
265
266 name.ln_number = number;
267 name.ln_type = glops->go_type;
268 bucket = &sdp->sd_gl_hash[gl_hash(&name)];
269
270 read_lock(&bucket->hb_lock);
271 gl = search_bucket(bucket, &name);
272 read_unlock(&bucket->hb_lock);
273
274 if (gl || !create) {
275 *glp = gl;
276 return 0;
277 }
278
279 gl = kmem_cache_alloc(gfs2_glock_cachep, GFP_KERNEL);
280 if (!gl)
281 return -ENOMEM;
282
283 memset(gl, 0, sizeof(struct gfs2_glock));
284
285 INIT_LIST_HEAD(&gl->gl_list);
286 gl->gl_name = name;
287 kref_init(&gl->gl_ref);
288
289 spin_lock_init(&gl->gl_spin);
290
291 gl->gl_state = LM_ST_UNLOCKED;
292 INIT_LIST_HEAD(&gl->gl_holders);
293 INIT_LIST_HEAD(&gl->gl_waiters1);
294 INIT_LIST_HEAD(&gl->gl_waiters2);
295 INIT_LIST_HEAD(&gl->gl_waiters3);
296
297 gl->gl_ops = glops;
298
299 gl->gl_bucket = bucket;
300 INIT_LIST_HEAD(&gl->gl_reclaim);
301
302 gl->gl_sbd = sdp;
303
304 lops_init_le(&gl->gl_le, &gfs2_glock_lops);
305 INIT_LIST_HEAD(&gl->gl_ail_list);
306
307 /* If this glock protects actual on-disk data or metadata blocks,
308 create a VFS inode to manage the pages/buffers holding them. */
309 if (glops == &gfs2_inode_glops ||
310 glops == &gfs2_rgrp_glops ||
311 glops == &gfs2_meta_glops) {
312 gl->gl_aspace = gfs2_aspace_get(sdp);
313 if (!gl->gl_aspace) {
314 error = -ENOMEM;
315 goto fail;
316 }
317 }
318
319 error = gfs2_lm_get_lock(sdp, &name, &gl->gl_lock);
320 if (error)
321 goto fail_aspace;
322
David Teiglandb3b94fa2006-01-16 16:50:04 +0000323 write_lock(&bucket->hb_lock);
324 tmp = search_bucket(bucket, &name);
325 if (tmp) {
326 write_unlock(&bucket->hb_lock);
327 glock_free(gl);
328 gl = tmp;
329 } else {
330 list_add_tail(&gl->gl_list, &bucket->hb_list);
331 write_unlock(&bucket->hb_lock);
332 }
333
334 *glp = gl;
335
336 return 0;
337
338 fail_aspace:
339 if (gl->gl_aspace)
340 gfs2_aspace_put(gl->gl_aspace);
341
342 fail:
343 kmem_cache_free(gfs2_glock_cachep, gl);
344
345 return error;
346}
347
348/**
349 * gfs2_holder_init - initialize a struct gfs2_holder in the default way
350 * @gl: the glock
351 * @state: the state we're requesting
352 * @flags: the modifier flags
353 * @gh: the holder structure
354 *
355 */
356
Steven Whitehouse190562b2006-04-20 16:57:23 -0400357void gfs2_holder_init(struct gfs2_glock *gl, unsigned int state, unsigned flags,
David Teiglandb3b94fa2006-01-16 16:50:04 +0000358 struct gfs2_holder *gh)
359{
360 INIT_LIST_HEAD(&gh->gh_list);
361 gh->gh_gl = gl;
Steven Whitehoused0dc80d2006-03-29 14:36:49 -0500362 gh->gh_ip = (unsigned long)__builtin_return_address(0);
Steven Whitehouse190562b2006-04-20 16:57:23 -0400363 gh->gh_owner = current;
David Teiglandb3b94fa2006-01-16 16:50:04 +0000364 gh->gh_state = state;
365 gh->gh_flags = flags;
366 gh->gh_error = 0;
367 gh->gh_iflags = 0;
368 init_completion(&gh->gh_wait);
369
370 if (gh->gh_state == LM_ST_EXCLUSIVE)
371 gh->gh_flags |= GL_LOCAL_EXCL;
372
373 gfs2_glock_hold(gl);
374}
375
376/**
377 * gfs2_holder_reinit - reinitialize a struct gfs2_holder so we can requeue it
378 * @state: the state we're requesting
379 * @flags: the modifier flags
380 * @gh: the holder structure
381 *
382 * Don't mess with the glock.
383 *
384 */
385
Steven Whitehouse190562b2006-04-20 16:57:23 -0400386void gfs2_holder_reinit(unsigned int state, unsigned flags, struct gfs2_holder *gh)
David Teiglandb3b94fa2006-01-16 16:50:04 +0000387{
388 gh->gh_state = state;
Steven Whitehouse579b78a2006-04-26 14:58:26 -0400389 gh->gh_flags = flags;
David Teiglandb3b94fa2006-01-16 16:50:04 +0000390 if (gh->gh_state == LM_ST_EXCLUSIVE)
391 gh->gh_flags |= GL_LOCAL_EXCL;
392
393 gh->gh_iflags &= 1 << HIF_ALLOCED;
Steven Whitehoused0dc80d2006-03-29 14:36:49 -0500394 gh->gh_ip = (unsigned long)__builtin_return_address(0);
David Teiglandb3b94fa2006-01-16 16:50:04 +0000395}
396
397/**
398 * gfs2_holder_uninit - uninitialize a holder structure (drop glock reference)
399 * @gh: the holder structure
400 *
401 */
402
403void gfs2_holder_uninit(struct gfs2_holder *gh)
404{
405 gfs2_glock_put(gh->gh_gl);
406 gh->gh_gl = NULL;
Steven Whitehoused0dc80d2006-03-29 14:36:49 -0500407 gh->gh_ip = 0;
David Teiglandb3b94fa2006-01-16 16:50:04 +0000408}
409
410/**
411 * gfs2_holder_get - get a struct gfs2_holder structure
412 * @gl: the glock
413 * @state: the state we're requesting
414 * @flags: the modifier flags
415 * @gfp_flags: __GFP_NOFAIL
416 *
417 * Figure out how big an impact this function has. Either:
418 * 1) Replace it with a cache of structures hanging off the struct gfs2_sbd
419 * 2) Leave it like it is
420 *
421 * Returns: the holder structure, NULL on ENOMEM
422 */
423
424struct gfs2_holder *gfs2_holder_get(struct gfs2_glock *gl, unsigned int state,
425 int flags, gfp_t gfp_flags)
426{
427 struct gfs2_holder *gh;
428
429 gh = kmalloc(sizeof(struct gfs2_holder), gfp_flags);
430 if (!gh)
431 return NULL;
432
433 gfs2_holder_init(gl, state, flags, gh);
434 set_bit(HIF_ALLOCED, &gh->gh_iflags);
Steven Whitehoused0dc80d2006-03-29 14:36:49 -0500435 gh->gh_ip = (unsigned long)__builtin_return_address(0);
David Teiglandb3b94fa2006-01-16 16:50:04 +0000436 return gh;
437}
438
439/**
440 * gfs2_holder_put - get rid of a struct gfs2_holder structure
441 * @gh: the holder structure
442 *
443 */
444
445void gfs2_holder_put(struct gfs2_holder *gh)
446{
447 gfs2_holder_uninit(gh);
448 kfree(gh);
449}
450
451/**
David Teiglandb3b94fa2006-01-16 16:50:04 +0000452 * rq_mutex - process a mutex request in the queue
453 * @gh: the glock holder
454 *
455 * Returns: 1 if the queue is blocked
456 */
457
458static int rq_mutex(struct gfs2_holder *gh)
459{
460 struct gfs2_glock *gl = gh->gh_gl;
461
462 list_del_init(&gh->gh_list);
463 /* gh->gh_error never examined. */
464 set_bit(GLF_LOCK, &gl->gl_flags);
465 complete(&gh->gh_wait);
466
467 return 1;
468}
469
470/**
471 * rq_promote - process a promote request in the queue
472 * @gh: the glock holder
473 *
474 * Acquire a new inter-node lock, or change a lock state to more restrictive.
475 *
476 * Returns: 1 if the queue is blocked
477 */
478
479static int rq_promote(struct gfs2_holder *gh)
480{
481 struct gfs2_glock *gl = gh->gh_gl;
482 struct gfs2_sbd *sdp = gl->gl_sbd;
483 struct gfs2_glock_operations *glops = gl->gl_ops;
David Teiglandb3b94fa2006-01-16 16:50:04 +0000484
485 if (!relaxed_state_ok(gl->gl_state, gh->gh_state, gh->gh_flags)) {
486 if (list_empty(&gl->gl_holders)) {
487 gl->gl_req_gh = gh;
488 set_bit(GLF_LOCK, &gl->gl_flags);
489 spin_unlock(&gl->gl_spin);
490
491 if (atomic_read(&sdp->sd_reclaim_count) >
492 gfs2_tune_get(sdp, gt_reclaim_limit) &&
493 !(gh->gh_flags & LM_FLAG_PRIORITY)) {
494 gfs2_reclaim_glock(sdp);
495 gfs2_reclaim_glock(sdp);
496 }
497
498 glops->go_xmote_th(gl, gh->gh_state,
499 gh->gh_flags);
500
501 spin_lock(&gl->gl_spin);
502 }
503 return 1;
504 }
505
506 if (list_empty(&gl->gl_holders)) {
507 set_bit(HIF_FIRST, &gh->gh_iflags);
508 set_bit(GLF_LOCK, &gl->gl_flags);
David Teiglandb3b94fa2006-01-16 16:50:04 +0000509 } else {
510 struct gfs2_holder *next_gh;
511 if (gh->gh_flags & GL_LOCAL_EXCL)
512 return 1;
513 next_gh = list_entry(gl->gl_holders.next, struct gfs2_holder,
514 gh_list);
515 if (next_gh->gh_flags & GL_LOCAL_EXCL)
516 return 1;
David Teiglandb3b94fa2006-01-16 16:50:04 +0000517 }
518
519 list_move_tail(&gh->gh_list, &gl->gl_holders);
520 gh->gh_error = 0;
521 set_bit(HIF_HOLDER, &gh->gh_iflags);
522
David Teiglandb3b94fa2006-01-16 16:50:04 +0000523 complete(&gh->gh_wait);
524
525 return 0;
526}
527
528/**
529 * rq_demote - process a demote request in the queue
530 * @gh: the glock holder
531 *
532 * Returns: 1 if the queue is blocked
533 */
534
535static int rq_demote(struct gfs2_holder *gh)
536{
537 struct gfs2_glock *gl = gh->gh_gl;
538 struct gfs2_glock_operations *glops = gl->gl_ops;
539
540 if (!list_empty(&gl->gl_holders))
541 return 1;
542
543 if (gl->gl_state == gh->gh_state || gl->gl_state == LM_ST_UNLOCKED) {
544 list_del_init(&gh->gh_list);
545 gh->gh_error = 0;
546 spin_unlock(&gl->gl_spin);
547 if (test_bit(HIF_DEALLOC, &gh->gh_iflags))
548 gfs2_holder_put(gh);
549 else
550 complete(&gh->gh_wait);
551 spin_lock(&gl->gl_spin);
552 } else {
553 gl->gl_req_gh = gh;
554 set_bit(GLF_LOCK, &gl->gl_flags);
555 spin_unlock(&gl->gl_spin);
556
557 if (gh->gh_state == LM_ST_UNLOCKED ||
558 gl->gl_state != LM_ST_EXCLUSIVE)
559 glops->go_drop_th(gl);
560 else
561 glops->go_xmote_th(gl, gh->gh_state, gh->gh_flags);
562
563 spin_lock(&gl->gl_spin);
564 }
565
566 return 0;
567}
568
569/**
570 * rq_greedy - process a queued request to drop greedy status
571 * @gh: the glock holder
572 *
573 * Returns: 1 if the queue is blocked
574 */
575
576static int rq_greedy(struct gfs2_holder *gh)
577{
578 struct gfs2_glock *gl = gh->gh_gl;
579
580 list_del_init(&gh->gh_list);
581 /* gh->gh_error never examined. */
582 clear_bit(GLF_GREEDY, &gl->gl_flags);
583 spin_unlock(&gl->gl_spin);
584
585 gfs2_holder_uninit(gh);
586 kfree(container_of(gh, struct greedy, gr_gh));
587
588 spin_lock(&gl->gl_spin);
589
590 return 0;
591}
592
593/**
594 * run_queue - process holder structures on a glock
595 * @gl: the glock
596 *
597 */
David Teiglandb3b94fa2006-01-16 16:50:04 +0000598static void run_queue(struct gfs2_glock *gl)
599{
600 struct gfs2_holder *gh;
601 int blocked = 1;
602
603 for (;;) {
604 if (test_bit(GLF_LOCK, &gl->gl_flags))
605 break;
606
607 if (!list_empty(&gl->gl_waiters1)) {
608 gh = list_entry(gl->gl_waiters1.next,
609 struct gfs2_holder, gh_list);
610
611 if (test_bit(HIF_MUTEX, &gh->gh_iflags))
612 blocked = rq_mutex(gh);
613 else
614 gfs2_assert_warn(gl->gl_sbd, 0);
615
616 } else if (!list_empty(&gl->gl_waiters2) &&
617 !test_bit(GLF_SKIP_WAITERS2, &gl->gl_flags)) {
618 gh = list_entry(gl->gl_waiters2.next,
619 struct gfs2_holder, gh_list);
620
621 if (test_bit(HIF_DEMOTE, &gh->gh_iflags))
622 blocked = rq_demote(gh);
623 else if (test_bit(HIF_GREEDY, &gh->gh_iflags))
624 blocked = rq_greedy(gh);
625 else
626 gfs2_assert_warn(gl->gl_sbd, 0);
627
628 } else if (!list_empty(&gl->gl_waiters3)) {
629 gh = list_entry(gl->gl_waiters3.next,
630 struct gfs2_holder, gh_list);
631
632 if (test_bit(HIF_PROMOTE, &gh->gh_iflags))
633 blocked = rq_promote(gh);
634 else
635 gfs2_assert_warn(gl->gl_sbd, 0);
636
637 } else
638 break;
639
640 if (blocked)
641 break;
642 }
643}
644
645/**
646 * gfs2_glmutex_lock - acquire a local lock on a glock
647 * @gl: the glock
648 *
649 * Gives caller exclusive access to manipulate a glock structure.
650 */
651
652void gfs2_glmutex_lock(struct gfs2_glock *gl)
653{
654 struct gfs2_holder gh;
655
656 gfs2_holder_init(gl, 0, 0, &gh);
657 set_bit(HIF_MUTEX, &gh.gh_iflags);
658
659 spin_lock(&gl->gl_spin);
660 if (test_and_set_bit(GLF_LOCK, &gl->gl_flags))
661 list_add_tail(&gh.gh_list, &gl->gl_waiters1);
662 else
663 complete(&gh.gh_wait);
664 spin_unlock(&gl->gl_spin);
665
666 wait_for_completion(&gh.gh_wait);
667 gfs2_holder_uninit(&gh);
668}
669
670/**
671 * gfs2_glmutex_trylock - try to acquire a local lock on a glock
672 * @gl: the glock
673 *
674 * Returns: 1 if the glock is acquired
675 */
676
677int gfs2_glmutex_trylock(struct gfs2_glock *gl)
678{
679 int acquired = 1;
680
681 spin_lock(&gl->gl_spin);
682 if (test_and_set_bit(GLF_LOCK, &gl->gl_flags))
683 acquired = 0;
684 spin_unlock(&gl->gl_spin);
685
686 return acquired;
687}
688
689/**
690 * gfs2_glmutex_unlock - release a local lock on a glock
691 * @gl: the glock
692 *
693 */
694
695void gfs2_glmutex_unlock(struct gfs2_glock *gl)
696{
697 spin_lock(&gl->gl_spin);
698 clear_bit(GLF_LOCK, &gl->gl_flags);
699 run_queue(gl);
Steven Whitehouse190562b2006-04-20 16:57:23 -0400700 BUG_ON(!spin_is_locked(&gl->gl_spin));
David Teiglandb3b94fa2006-01-16 16:50:04 +0000701 spin_unlock(&gl->gl_spin);
702}
703
704/**
705 * handle_callback - add a demote request to a lock's queue
706 * @gl: the glock
707 * @state: the state the caller wants us to change to
708 *
709 */
710
711static void handle_callback(struct gfs2_glock *gl, unsigned int state)
712{
713 struct gfs2_holder *gh, *new_gh = NULL;
714
715 restart:
716 spin_lock(&gl->gl_spin);
717
718 list_for_each_entry(gh, &gl->gl_waiters2, gh_list) {
719 if (test_bit(HIF_DEMOTE, &gh->gh_iflags) &&
720 gl->gl_req_gh != gh) {
721 if (gh->gh_state != state)
722 gh->gh_state = LM_ST_UNLOCKED;
723 goto out;
724 }
725 }
726
727 if (new_gh) {
728 list_add_tail(&new_gh->gh_list, &gl->gl_waiters2);
729 new_gh = NULL;
730 } else {
731 spin_unlock(&gl->gl_spin);
732
Steven Whitehouse579b78a2006-04-26 14:58:26 -0400733 new_gh = gfs2_holder_get(gl, state, LM_FLAG_TRY,
David Teiglandb3b94fa2006-01-16 16:50:04 +0000734 GFP_KERNEL | __GFP_NOFAIL),
735 set_bit(HIF_DEMOTE, &new_gh->gh_iflags);
736 set_bit(HIF_DEALLOC, &new_gh->gh_iflags);
737
738 goto restart;
739 }
740
741 out:
742 spin_unlock(&gl->gl_spin);
743
744 if (new_gh)
745 gfs2_holder_put(new_gh);
746}
747
748/**
749 * state_change - record that the glock is now in a different state
750 * @gl: the glock
751 * @new_state the new state
752 *
753 */
754
755static void state_change(struct gfs2_glock *gl, unsigned int new_state)
756{
David Teiglandb3b94fa2006-01-16 16:50:04 +0000757 int held1, held2;
758
759 held1 = (gl->gl_state != LM_ST_UNLOCKED);
760 held2 = (new_state != LM_ST_UNLOCKED);
761
762 if (held1 != held2) {
David Teigland6a6b3d02006-02-23 10:11:47 +0000763 if (held2)
David Teiglandb3b94fa2006-01-16 16:50:04 +0000764 gfs2_glock_hold(gl);
David Teigland6a6b3d02006-02-23 10:11:47 +0000765 else
David Teiglandb3b94fa2006-01-16 16:50:04 +0000766 gfs2_glock_put(gl);
David Teiglandb3b94fa2006-01-16 16:50:04 +0000767 }
768
769 gl->gl_state = new_state;
770}
771
772/**
773 * xmote_bh - Called after the lock module is done acquiring a lock
774 * @gl: The glock in question
775 * @ret: the int returned from the lock module
776 *
777 */
778
779static void xmote_bh(struct gfs2_glock *gl, unsigned int ret)
780{
781 struct gfs2_sbd *sdp = gl->gl_sbd;
782 struct gfs2_glock_operations *glops = gl->gl_ops;
783 struct gfs2_holder *gh = gl->gl_req_gh;
784 int prev_state = gl->gl_state;
785 int op_done = 1;
786
787 gfs2_assert_warn(sdp, test_bit(GLF_LOCK, &gl->gl_flags));
788 gfs2_assert_warn(sdp, queue_empty(gl, &gl->gl_holders));
789 gfs2_assert_warn(sdp, !(ret & LM_OUT_ASYNC));
790
791 state_change(gl, ret & LM_OUT_ST_MASK);
792
793 if (prev_state != LM_ST_UNLOCKED && !(ret & LM_OUT_CACHEABLE)) {
794 if (glops->go_inval)
795 glops->go_inval(gl, DIO_METADATA | DIO_DATA);
796 } else if (gl->gl_state == LM_ST_DEFERRED) {
797 /* We might not want to do this here.
798 Look at moving to the inode glops. */
799 if (glops->go_inval)
800 glops->go_inval(gl, DIO_DATA);
801 }
802
803 /* Deal with each possible exit condition */
804
805 if (!gh)
806 gl->gl_stamp = jiffies;
807
808 else if (unlikely(test_bit(SDF_SHUTDOWN, &sdp->sd_flags))) {
809 spin_lock(&gl->gl_spin);
810 list_del_init(&gh->gh_list);
811 gh->gh_error = -EIO;
David Teiglandb3b94fa2006-01-16 16:50:04 +0000812 spin_unlock(&gl->gl_spin);
813
814 } else if (test_bit(HIF_DEMOTE, &gh->gh_iflags)) {
815 spin_lock(&gl->gl_spin);
816 list_del_init(&gh->gh_list);
817 if (gl->gl_state == gh->gh_state ||
818 gl->gl_state == LM_ST_UNLOCKED)
819 gh->gh_error = 0;
820 else {
821 if (gfs2_assert_warn(sdp, gh->gh_flags &
822 (LM_FLAG_TRY | LM_FLAG_TRY_1CB)) == -1)
823 fs_warn(sdp, "ret = 0x%.8X\n", ret);
824 gh->gh_error = GLR_TRYFAILED;
825 }
826 spin_unlock(&gl->gl_spin);
827
828 if (ret & LM_OUT_CANCELED)
829 handle_callback(gl, LM_ST_UNLOCKED); /* Lame */
830
831 } else if (ret & LM_OUT_CANCELED) {
832 spin_lock(&gl->gl_spin);
833 list_del_init(&gh->gh_list);
834 gh->gh_error = GLR_CANCELED;
David Teiglandb3b94fa2006-01-16 16:50:04 +0000835 spin_unlock(&gl->gl_spin);
836
837 } else if (relaxed_state_ok(gl->gl_state, gh->gh_state, gh->gh_flags)) {
838 spin_lock(&gl->gl_spin);
839 list_move_tail(&gh->gh_list, &gl->gl_holders);
840 gh->gh_error = 0;
841 set_bit(HIF_HOLDER, &gh->gh_iflags);
842 spin_unlock(&gl->gl_spin);
843
844 set_bit(HIF_FIRST, &gh->gh_iflags);
845
846 op_done = 0;
847
848 } else if (gh->gh_flags & (LM_FLAG_TRY | LM_FLAG_TRY_1CB)) {
849 spin_lock(&gl->gl_spin);
850 list_del_init(&gh->gh_list);
851 gh->gh_error = GLR_TRYFAILED;
David Teiglandb3b94fa2006-01-16 16:50:04 +0000852 spin_unlock(&gl->gl_spin);
853
854 } else {
855 if (gfs2_assert_withdraw(sdp, 0) == -1)
856 fs_err(sdp, "ret = 0x%.8X\n", ret);
857 }
858
859 if (glops->go_xmote_bh)
860 glops->go_xmote_bh(gl);
861
862 if (op_done) {
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
871 gfs2_glock_put(gl);
872
873 if (gh) {
874 if (test_bit(HIF_DEALLOC, &gh->gh_iflags))
875 gfs2_holder_put(gh);
876 else
877 complete(&gh->gh_wait);
878 }
879}
880
881/**
882 * gfs2_glock_xmote_th - Call into the lock module to acquire or change a glock
883 * @gl: The glock in question
884 * @state: the requested state
885 * @flags: modifier flags to the lock call
886 *
887 */
888
889void gfs2_glock_xmote_th(struct gfs2_glock *gl, unsigned int state, int flags)
890{
891 struct gfs2_sbd *sdp = gl->gl_sbd;
892 struct gfs2_glock_operations *glops = gl->gl_ops;
893 int lck_flags = flags & (LM_FLAG_TRY | LM_FLAG_TRY_1CB |
894 LM_FLAG_NOEXP | LM_FLAG_ANY |
895 LM_FLAG_PRIORITY);
896 unsigned int lck_ret;
897
898 gfs2_assert_warn(sdp, test_bit(GLF_LOCK, &gl->gl_flags));
899 gfs2_assert_warn(sdp, queue_empty(gl, &gl->gl_holders));
900 gfs2_assert_warn(sdp, state != LM_ST_UNLOCKED);
901 gfs2_assert_warn(sdp, state != gl->gl_state);
902
903 if (gl->gl_state == LM_ST_EXCLUSIVE) {
904 if (glops->go_sync)
905 glops->go_sync(gl,
906 DIO_METADATA | DIO_DATA | DIO_RELEASE);
907 }
908
909 gfs2_glock_hold(gl);
910 gl->gl_req_bh = xmote_bh;
911
David Teiglandb3b94fa2006-01-16 16:50:04 +0000912 lck_ret = gfs2_lm_lock(sdp, gl->gl_lock, gl->gl_state, state,
913 lck_flags);
914
915 if (gfs2_assert_withdraw(sdp, !(lck_ret & LM_OUT_ERROR)))
916 return;
917
918 if (lck_ret & LM_OUT_ASYNC)
919 gfs2_assert_warn(sdp, lck_ret == LM_OUT_ASYNC);
920 else
921 xmote_bh(gl, lck_ret);
922}
923
924/**
925 * drop_bh - Called after a lock module unlock completes
926 * @gl: the glock
927 * @ret: the return status
928 *
929 * Doesn't wake up the process waiting on the struct gfs2_holder (if any)
930 * Doesn't drop the reference on the glock the top half took out
931 *
932 */
933
934static void drop_bh(struct gfs2_glock *gl, unsigned int ret)
935{
936 struct gfs2_sbd *sdp = gl->gl_sbd;
937 struct gfs2_glock_operations *glops = gl->gl_ops;
938 struct gfs2_holder *gh = gl->gl_req_gh;
939
940 clear_bit(GLF_PREFETCH, &gl->gl_flags);
941
942 gfs2_assert_warn(sdp, test_bit(GLF_LOCK, &gl->gl_flags));
943 gfs2_assert_warn(sdp, queue_empty(gl, &gl->gl_holders));
944 gfs2_assert_warn(sdp, !ret);
945
946 state_change(gl, LM_ST_UNLOCKED);
947
948 if (glops->go_inval)
949 glops->go_inval(gl, DIO_METADATA | DIO_DATA);
950
951 if (gh) {
952 spin_lock(&gl->gl_spin);
953 list_del_init(&gh->gh_list);
954 gh->gh_error = 0;
955 spin_unlock(&gl->gl_spin);
956 }
957
958 if (glops->go_drop_bh)
959 glops->go_drop_bh(gl);
960
961 spin_lock(&gl->gl_spin);
962 gl->gl_req_gh = NULL;
963 gl->gl_req_bh = NULL;
964 clear_bit(GLF_LOCK, &gl->gl_flags);
965 run_queue(gl);
966 spin_unlock(&gl->gl_spin);
967
968 gfs2_glock_put(gl);
969
970 if (gh) {
971 if (test_bit(HIF_DEALLOC, &gh->gh_iflags))
972 gfs2_holder_put(gh);
973 else
974 complete(&gh->gh_wait);
975 }
976}
977
978/**
979 * gfs2_glock_drop_th - call into the lock module to unlock a lock
980 * @gl: the glock
981 *
982 */
983
984void gfs2_glock_drop_th(struct gfs2_glock *gl)
985{
986 struct gfs2_sbd *sdp = gl->gl_sbd;
987 struct gfs2_glock_operations *glops = gl->gl_ops;
988 unsigned int ret;
989
990 gfs2_assert_warn(sdp, test_bit(GLF_LOCK, &gl->gl_flags));
991 gfs2_assert_warn(sdp, queue_empty(gl, &gl->gl_holders));
992 gfs2_assert_warn(sdp, gl->gl_state != LM_ST_UNLOCKED);
993
994 if (gl->gl_state == LM_ST_EXCLUSIVE) {
995 if (glops->go_sync)
996 glops->go_sync(gl,
997 DIO_METADATA | DIO_DATA | DIO_RELEASE);
998 }
999
1000 gfs2_glock_hold(gl);
1001 gl->gl_req_bh = drop_bh;
1002
David Teiglandb3b94fa2006-01-16 16:50:04 +00001003 ret = gfs2_lm_unlock(sdp, gl->gl_lock, gl->gl_state);
1004
1005 if (gfs2_assert_withdraw(sdp, !(ret & LM_OUT_ERROR)))
1006 return;
1007
1008 if (!ret)
1009 drop_bh(gl, ret);
1010 else
1011 gfs2_assert_warn(sdp, ret == LM_OUT_ASYNC);
1012}
1013
1014/**
1015 * do_cancels - cancel requests for locks stuck waiting on an expire flag
1016 * @gh: the LM_FLAG_PRIORITY holder waiting to acquire the lock
1017 *
1018 * Don't cancel GL_NOCANCEL requests.
1019 */
1020
1021static void do_cancels(struct gfs2_holder *gh)
1022{
1023 struct gfs2_glock *gl = gh->gh_gl;
1024
1025 spin_lock(&gl->gl_spin);
1026
1027 while (gl->gl_req_gh != gh &&
1028 !test_bit(HIF_HOLDER, &gh->gh_iflags) &&
1029 !list_empty(&gh->gh_list)) {
1030 if (gl->gl_req_bh &&
1031 !(gl->gl_req_gh &&
1032 (gl->gl_req_gh->gh_flags & GL_NOCANCEL))) {
1033 spin_unlock(&gl->gl_spin);
1034 gfs2_lm_cancel(gl->gl_sbd, gl->gl_lock);
1035 msleep(100);
1036 spin_lock(&gl->gl_spin);
1037 } else {
1038 spin_unlock(&gl->gl_spin);
1039 msleep(100);
1040 spin_lock(&gl->gl_spin);
1041 }
1042 }
1043
1044 spin_unlock(&gl->gl_spin);
1045}
1046
1047/**
1048 * glock_wait_internal - wait on a glock acquisition
1049 * @gh: the glock holder
1050 *
1051 * Returns: 0 on success
1052 */
1053
1054static int glock_wait_internal(struct gfs2_holder *gh)
1055{
1056 struct gfs2_glock *gl = gh->gh_gl;
1057 struct gfs2_sbd *sdp = gl->gl_sbd;
1058 struct gfs2_glock_operations *glops = gl->gl_ops;
1059
1060 if (test_bit(HIF_ABORTED, &gh->gh_iflags))
1061 return -EIO;
1062
1063 if (gh->gh_flags & (LM_FLAG_TRY | LM_FLAG_TRY_1CB)) {
1064 spin_lock(&gl->gl_spin);
1065 if (gl->gl_req_gh != gh &&
1066 !test_bit(HIF_HOLDER, &gh->gh_iflags) &&
1067 !list_empty(&gh->gh_list)) {
1068 list_del_init(&gh->gh_list);
1069 gh->gh_error = GLR_TRYFAILED;
David Teiglandb3b94fa2006-01-16 16:50:04 +00001070 run_queue(gl);
1071 spin_unlock(&gl->gl_spin);
1072 return gh->gh_error;
1073 }
1074 spin_unlock(&gl->gl_spin);
1075 }
1076
1077 if (gh->gh_flags & LM_FLAG_PRIORITY)
1078 do_cancels(gh);
1079
1080 wait_for_completion(&gh->gh_wait);
1081
1082 if (gh->gh_error)
1083 return gh->gh_error;
1084
1085 gfs2_assert_withdraw(sdp, test_bit(HIF_HOLDER, &gh->gh_iflags));
1086 gfs2_assert_withdraw(sdp, relaxed_state_ok(gl->gl_state,
1087 gh->gh_state,
1088 gh->gh_flags));
1089
1090 if (test_bit(HIF_FIRST, &gh->gh_iflags)) {
1091 gfs2_assert_warn(sdp, test_bit(GLF_LOCK, &gl->gl_flags));
1092
1093 if (glops->go_lock) {
1094 gh->gh_error = glops->go_lock(gh);
1095 if (gh->gh_error) {
1096 spin_lock(&gl->gl_spin);
1097 list_del_init(&gh->gh_list);
David Teiglandb3b94fa2006-01-16 16:50:04 +00001098 spin_unlock(&gl->gl_spin);
1099 }
1100 }
1101
1102 spin_lock(&gl->gl_spin);
1103 gl->gl_req_gh = NULL;
1104 gl->gl_req_bh = NULL;
1105 clear_bit(GLF_LOCK, &gl->gl_flags);
David Teiglandb3b94fa2006-01-16 16:50:04 +00001106 run_queue(gl);
1107 spin_unlock(&gl->gl_spin);
1108 }
1109
1110 return gh->gh_error;
1111}
1112
1113static inline struct gfs2_holder *
1114find_holder_by_owner(struct list_head *head, struct task_struct *owner)
1115{
1116 struct gfs2_holder *gh;
1117
1118 list_for_each_entry(gh, head, gh_list) {
1119 if (gh->gh_owner == owner)
1120 return gh;
1121 }
1122
1123 return NULL;
1124}
1125
1126/**
David Teiglandb3b94fa2006-01-16 16:50:04 +00001127 * add_to_queue - Add a holder to the wait queue (but look for recursion)
1128 * @gh: the holder structure to add
1129 *
1130 */
1131
1132static void add_to_queue(struct gfs2_holder *gh)
1133{
1134 struct gfs2_glock *gl = gh->gh_gl;
1135 struct gfs2_holder *existing;
1136
Steven Whitehouse190562b2006-04-20 16:57:23 -04001137 BUG_ON(!gh->gh_owner);
1138
David Teiglandb3b94fa2006-01-16 16:50:04 +00001139 existing = find_holder_by_owner(&gl->gl_holders, gh->gh_owner);
1140 if (existing) {
Steven Whitehouse5965b1f2006-04-26 13:21:55 -04001141 print_symbol(KERN_WARNING "original: %s\n", existing->gh_ip);
1142 print_symbol(KERN_WARNING "new: %s\n", gh->gh_ip);
1143 BUG();
David Teiglandb3b94fa2006-01-16 16:50:04 +00001144 }
1145
1146 existing = find_holder_by_owner(&gl->gl_waiters3, gh->gh_owner);
1147 if (existing) {
Steven Whitehouse5965b1f2006-04-26 13:21:55 -04001148 print_symbol(KERN_WARNING "original: %s\n", existing->gh_ip);
1149 print_symbol(KERN_WARNING "new: %s\n", gh->gh_ip);
1150 BUG();
David Teiglandb3b94fa2006-01-16 16:50:04 +00001151 }
1152
David Teiglandb3b94fa2006-01-16 16:50:04 +00001153 if (gh->gh_flags & LM_FLAG_PRIORITY)
1154 list_add(&gh->gh_list, &gl->gl_waiters3);
1155 else
1156 list_add_tail(&gh->gh_list, &gl->gl_waiters3);
1157}
1158
1159/**
1160 * gfs2_glock_nq - enqueue a struct gfs2_holder onto a glock (acquire a glock)
1161 * @gh: the holder structure
1162 *
1163 * if (gh->gh_flags & GL_ASYNC), this never returns an error
1164 *
1165 * Returns: 0, GLR_TRYFAILED, or errno on failure
1166 */
1167
1168int gfs2_glock_nq(struct gfs2_holder *gh)
1169{
1170 struct gfs2_glock *gl = gh->gh_gl;
1171 struct gfs2_sbd *sdp = gl->gl_sbd;
1172 int error = 0;
1173
David Teiglandb3b94fa2006-01-16 16:50:04 +00001174 restart:
1175 if (unlikely(test_bit(SDF_SHUTDOWN, &sdp->sd_flags))) {
1176 set_bit(HIF_ABORTED, &gh->gh_iflags);
1177 return -EIO;
1178 }
1179
1180 set_bit(HIF_PROMOTE, &gh->gh_iflags);
1181
1182 spin_lock(&gl->gl_spin);
1183 add_to_queue(gh);
1184 run_queue(gl);
1185 spin_unlock(&gl->gl_spin);
1186
1187 if (!(gh->gh_flags & GL_ASYNC)) {
1188 error = glock_wait_internal(gh);
1189 if (error == GLR_CANCELED) {
Steven Whitehouse190562b2006-04-20 16:57:23 -04001190 msleep(100);
David Teiglandb3b94fa2006-01-16 16:50:04 +00001191 goto restart;
1192 }
1193 }
1194
1195 clear_bit(GLF_PREFETCH, &gl->gl_flags);
1196
1197 return error;
1198}
1199
1200/**
1201 * gfs2_glock_poll - poll to see if an async request has been completed
1202 * @gh: the holder
1203 *
1204 * Returns: 1 if the request is ready to be gfs2_glock_wait()ed on
1205 */
1206
1207int gfs2_glock_poll(struct gfs2_holder *gh)
1208{
1209 struct gfs2_glock *gl = gh->gh_gl;
1210 int ready = 0;
1211
1212 spin_lock(&gl->gl_spin);
1213
1214 if (test_bit(HIF_HOLDER, &gh->gh_iflags))
1215 ready = 1;
1216 else if (list_empty(&gh->gh_list)) {
1217 if (gh->gh_error == GLR_CANCELED) {
1218 spin_unlock(&gl->gl_spin);
Steven Whitehouse190562b2006-04-20 16:57:23 -04001219 msleep(100);
David Teiglandb3b94fa2006-01-16 16:50:04 +00001220 if (gfs2_glock_nq(gh))
1221 return 1;
1222 return 0;
1223 } else
1224 ready = 1;
1225 }
1226
1227 spin_unlock(&gl->gl_spin);
1228
1229 return ready;
1230}
1231
1232/**
1233 * gfs2_glock_wait - wait for a lock acquisition that ended in a GLR_ASYNC
1234 * @gh: the holder structure
1235 *
1236 * Returns: 0, GLR_TRYFAILED, or errno on failure
1237 */
1238
1239int gfs2_glock_wait(struct gfs2_holder *gh)
1240{
1241 int error;
1242
1243 error = glock_wait_internal(gh);
1244 if (error == GLR_CANCELED) {
Steven Whitehouse190562b2006-04-20 16:57:23 -04001245 msleep(100);
David Teiglandb3b94fa2006-01-16 16:50:04 +00001246 gh->gh_flags &= ~GL_ASYNC;
1247 error = gfs2_glock_nq(gh);
1248 }
1249
1250 return error;
1251}
1252
1253/**
1254 * gfs2_glock_dq - dequeue a struct gfs2_holder from a glock (release a glock)
1255 * @gh: the glock holder
1256 *
1257 */
1258
1259void gfs2_glock_dq(struct gfs2_holder *gh)
1260{
1261 struct gfs2_glock *gl = gh->gh_gl;
David Teiglandb3b94fa2006-01-16 16:50:04 +00001262 struct gfs2_glock_operations *glops = gl->gl_ops;
1263
David Teiglandb3b94fa2006-01-16 16:50:04 +00001264 if (gh->gh_flags & GL_SYNC)
1265 set_bit(GLF_SYNC, &gl->gl_flags);
1266
1267 if (gh->gh_flags & GL_NOCACHE)
1268 handle_callback(gl, LM_ST_UNLOCKED);
1269
1270 gfs2_glmutex_lock(gl);
1271
1272 spin_lock(&gl->gl_spin);
1273 list_del_init(&gh->gh_list);
1274
1275 if (list_empty(&gl->gl_holders)) {
1276 spin_unlock(&gl->gl_spin);
1277
1278 if (glops->go_unlock)
1279 glops->go_unlock(gh);
1280
1281 if (test_bit(GLF_SYNC, &gl->gl_flags)) {
1282 if (glops->go_sync)
1283 glops->go_sync(gl, DIO_METADATA | DIO_DATA);
1284 }
1285
1286 gl->gl_stamp = jiffies;
1287
1288 spin_lock(&gl->gl_spin);
1289 }
1290
1291 clear_bit(GLF_LOCK, &gl->gl_flags);
1292 run_queue(gl);
1293 spin_unlock(&gl->gl_spin);
1294}
1295
1296/**
1297 * gfs2_glock_prefetch - Try to prefetch a glock
1298 * @gl: the glock
1299 * @state: the state to prefetch in
1300 * @flags: flags passed to go_xmote_th()
1301 *
1302 */
1303
1304void gfs2_glock_prefetch(struct gfs2_glock *gl, unsigned int state, int flags)
1305{
1306 struct gfs2_glock_operations *glops = gl->gl_ops;
1307
1308 spin_lock(&gl->gl_spin);
1309
1310 if (test_bit(GLF_LOCK, &gl->gl_flags) ||
1311 !list_empty(&gl->gl_holders) ||
1312 !list_empty(&gl->gl_waiters1) ||
1313 !list_empty(&gl->gl_waiters2) ||
1314 !list_empty(&gl->gl_waiters3) ||
1315 relaxed_state_ok(gl->gl_state, state, flags)) {
1316 spin_unlock(&gl->gl_spin);
1317 return;
1318 }
1319
1320 set_bit(GLF_PREFETCH, &gl->gl_flags);
1321 set_bit(GLF_LOCK, &gl->gl_flags);
1322 spin_unlock(&gl->gl_spin);
1323
1324 glops->go_xmote_th(gl, state, flags);
David Teiglandb3b94fa2006-01-16 16:50:04 +00001325}
1326
1327/**
1328 * gfs2_glock_force_drop - Force a glock to be uncached
1329 * @gl: the glock
1330 *
1331 */
1332
1333void gfs2_glock_force_drop(struct gfs2_glock *gl)
1334{
1335 struct gfs2_holder gh;
1336
Steven Whitehouse579b78a2006-04-26 14:58:26 -04001337 gfs2_holder_init(gl, LM_ST_UNLOCKED, 0, &gh);
David Teiglandb3b94fa2006-01-16 16:50:04 +00001338 set_bit(HIF_DEMOTE, &gh.gh_iflags);
1339
1340 spin_lock(&gl->gl_spin);
1341 list_add_tail(&gh.gh_list, &gl->gl_waiters2);
1342 run_queue(gl);
1343 spin_unlock(&gl->gl_spin);
1344
1345 wait_for_completion(&gh.gh_wait);
1346 gfs2_holder_uninit(&gh);
1347}
1348
1349static void greedy_work(void *data)
1350{
David Teiglande7f5c012006-04-27 11:25:45 -04001351 struct greedy *gr = data;
David Teiglandb3b94fa2006-01-16 16:50:04 +00001352 struct gfs2_holder *gh = &gr->gr_gh;
1353 struct gfs2_glock *gl = gh->gh_gl;
1354 struct gfs2_glock_operations *glops = gl->gl_ops;
1355
1356 clear_bit(GLF_SKIP_WAITERS2, &gl->gl_flags);
1357
1358 if (glops->go_greedy)
1359 glops->go_greedy(gl);
1360
1361 spin_lock(&gl->gl_spin);
1362
1363 if (list_empty(&gl->gl_waiters2)) {
1364 clear_bit(GLF_GREEDY, &gl->gl_flags);
1365 spin_unlock(&gl->gl_spin);
1366 gfs2_holder_uninit(gh);
1367 kfree(gr);
1368 } else {
1369 gfs2_glock_hold(gl);
1370 list_add_tail(&gh->gh_list, &gl->gl_waiters2);
1371 run_queue(gl);
1372 spin_unlock(&gl->gl_spin);
1373 gfs2_glock_put(gl);
1374 }
1375}
1376
1377/**
1378 * gfs2_glock_be_greedy -
1379 * @gl:
1380 * @time:
1381 *
1382 * Returns: 0 if go_greedy will be called, 1 otherwise
1383 */
1384
1385int gfs2_glock_be_greedy(struct gfs2_glock *gl, unsigned int time)
1386{
1387 struct greedy *gr;
1388 struct gfs2_holder *gh;
1389
1390 if (!time ||
1391 gl->gl_sbd->sd_args.ar_localcaching ||
1392 test_and_set_bit(GLF_GREEDY, &gl->gl_flags))
1393 return 1;
1394
1395 gr = kmalloc(sizeof(struct greedy), GFP_KERNEL);
1396 if (!gr) {
1397 clear_bit(GLF_GREEDY, &gl->gl_flags);
1398 return 1;
1399 }
1400 gh = &gr->gr_gh;
1401
Steven Whitehouse579b78a2006-04-26 14:58:26 -04001402 gfs2_holder_init(gl, 0, 0, gh);
David Teiglandb3b94fa2006-01-16 16:50:04 +00001403 set_bit(HIF_GREEDY, &gh->gh_iflags);
1404 INIT_WORK(&gr->gr_work, greedy_work, gr);
1405
1406 set_bit(GLF_SKIP_WAITERS2, &gl->gl_flags);
1407 schedule_delayed_work(&gr->gr_work, time);
1408
1409 return 0;
1410}
1411
1412/**
David Teiglandb3b94fa2006-01-16 16:50:04 +00001413 * gfs2_glock_dq_uninit - dequeue a holder from a glock and initialize it
1414 * @gh: the holder structure
1415 *
1416 */
1417
1418void gfs2_glock_dq_uninit(struct gfs2_holder *gh)
1419{
1420 gfs2_glock_dq(gh);
1421 gfs2_holder_uninit(gh);
1422}
1423
1424/**
1425 * gfs2_glock_nq_num - acquire a glock based on lock number
1426 * @sdp: the filesystem
1427 * @number: the lock number
1428 * @glops: the glock operations for the type of glock
1429 * @state: the state to acquire the glock in
1430 * @flags: modifier flags for the aquisition
1431 * @gh: the struct gfs2_holder
1432 *
1433 * Returns: errno
1434 */
1435
1436int gfs2_glock_nq_num(struct gfs2_sbd *sdp, uint64_t number,
1437 struct gfs2_glock_operations *glops, unsigned int state,
1438 int flags, struct gfs2_holder *gh)
1439{
1440 struct gfs2_glock *gl;
1441 int error;
1442
1443 error = gfs2_glock_get(sdp, number, glops, CREATE, &gl);
1444 if (!error) {
1445 error = gfs2_glock_nq_init(gl, state, flags, gh);
1446 gfs2_glock_put(gl);
1447 }
1448
1449 return error;
1450}
1451
1452/**
1453 * glock_compare - Compare two struct gfs2_glock structures for sorting
1454 * @arg_a: the first structure
1455 * @arg_b: the second structure
1456 *
1457 */
1458
1459static int glock_compare(const void *arg_a, const void *arg_b)
1460{
1461 struct gfs2_holder *gh_a = *(struct gfs2_holder **)arg_a;
1462 struct gfs2_holder *gh_b = *(struct gfs2_holder **)arg_b;
1463 struct lm_lockname *a = &gh_a->gh_gl->gl_name;
1464 struct lm_lockname *b = &gh_b->gh_gl->gl_name;
1465 int ret = 0;
1466
1467 if (a->ln_number > b->ln_number)
1468 ret = 1;
1469 else if (a->ln_number < b->ln_number)
1470 ret = -1;
1471 else {
1472 if (gh_a->gh_state == LM_ST_SHARED &&
1473 gh_b->gh_state == LM_ST_EXCLUSIVE)
1474 ret = 1;
1475 else if (!(gh_a->gh_flags & GL_LOCAL_EXCL) &&
1476 (gh_b->gh_flags & GL_LOCAL_EXCL))
1477 ret = 1;
1478 }
1479
1480 return ret;
1481}
1482
1483/**
1484 * nq_m_sync - synchonously acquire more than one glock in deadlock free order
1485 * @num_gh: the number of structures
1486 * @ghs: an array of struct gfs2_holder structures
1487 *
1488 * Returns: 0 on success (all glocks acquired),
1489 * errno on failure (no glocks acquired)
1490 */
1491
1492static int nq_m_sync(unsigned int num_gh, struct gfs2_holder *ghs,
1493 struct gfs2_holder **p)
1494{
1495 unsigned int x;
1496 int error = 0;
1497
1498 for (x = 0; x < num_gh; x++)
1499 p[x] = &ghs[x];
1500
1501 sort(p, num_gh, sizeof(struct gfs2_holder *), glock_compare, NULL);
1502
1503 for (x = 0; x < num_gh; x++) {
1504 p[x]->gh_flags &= ~(LM_FLAG_TRY | GL_ASYNC);
1505
1506 error = gfs2_glock_nq(p[x]);
1507 if (error) {
1508 while (x--)
1509 gfs2_glock_dq(p[x]);
1510 break;
1511 }
1512 }
1513
1514 return error;
1515}
1516
1517/**
1518 * gfs2_glock_nq_m - acquire multiple glocks
1519 * @num_gh: the number of structures
1520 * @ghs: an array of struct gfs2_holder structures
1521 *
1522 * Figure out how big an impact this function has. Either:
1523 * 1) Replace this code with code that calls gfs2_glock_prefetch()
1524 * 2) Forget async stuff and just call nq_m_sync()
1525 * 3) Leave it like it is
1526 *
1527 * Returns: 0 on success (all glocks acquired),
1528 * errno on failure (no glocks acquired)
1529 */
1530
1531int gfs2_glock_nq_m(unsigned int num_gh, struct gfs2_holder *ghs)
1532{
1533 int *e;
1534 unsigned int x;
1535 int borked = 0, serious = 0;
1536 int error = 0;
1537
1538 if (!num_gh)
1539 return 0;
1540
1541 if (num_gh == 1) {
1542 ghs->gh_flags &= ~(LM_FLAG_TRY | GL_ASYNC);
1543 return gfs2_glock_nq(ghs);
1544 }
1545
1546 e = kcalloc(num_gh, sizeof(struct gfs2_holder *), GFP_KERNEL);
1547 if (!e)
1548 return -ENOMEM;
1549
1550 for (x = 0; x < num_gh; x++) {
1551 ghs[x].gh_flags |= LM_FLAG_TRY | GL_ASYNC;
1552 error = gfs2_glock_nq(&ghs[x]);
1553 if (error) {
1554 borked = 1;
1555 serious = error;
1556 num_gh = x;
1557 break;
1558 }
1559 }
1560
1561 for (x = 0; x < num_gh; x++) {
1562 error = e[x] = glock_wait_internal(&ghs[x]);
1563 if (error) {
1564 borked = 1;
1565 if (error != GLR_TRYFAILED && error != GLR_CANCELED)
1566 serious = error;
1567 }
1568 }
1569
1570 if (!borked) {
1571 kfree(e);
1572 return 0;
1573 }
1574
1575 for (x = 0; x < num_gh; x++)
1576 if (!e[x])
1577 gfs2_glock_dq(&ghs[x]);
1578
1579 if (serious)
1580 error = serious;
1581 else {
1582 for (x = 0; x < num_gh; x++)
1583 gfs2_holder_reinit(ghs[x].gh_state, ghs[x].gh_flags,
1584 &ghs[x]);
1585 error = nq_m_sync(num_gh, ghs, (struct gfs2_holder **)e);
1586 }
1587
1588 kfree(e);
1589
1590 return error;
1591}
1592
1593/**
1594 * gfs2_glock_dq_m - release multiple glocks
1595 * @num_gh: the number of structures
1596 * @ghs: an array of struct gfs2_holder structures
1597 *
1598 */
1599
1600void gfs2_glock_dq_m(unsigned int num_gh, struct gfs2_holder *ghs)
1601{
1602 unsigned int x;
1603
1604 for (x = 0; x < num_gh; x++)
1605 gfs2_glock_dq(&ghs[x]);
1606}
1607
1608/**
1609 * gfs2_glock_dq_uninit_m - release multiple glocks
1610 * @num_gh: the number of structures
1611 * @ghs: an array of struct gfs2_holder structures
1612 *
1613 */
1614
1615void gfs2_glock_dq_uninit_m(unsigned int num_gh, struct gfs2_holder *ghs)
1616{
1617 unsigned int x;
1618
1619 for (x = 0; x < num_gh; x++)
1620 gfs2_glock_dq_uninit(&ghs[x]);
1621}
1622
1623/**
1624 * gfs2_glock_prefetch_num - prefetch a glock based on lock number
1625 * @sdp: the filesystem
1626 * @number: the lock number
1627 * @glops: the glock operations for the type of glock
1628 * @state: the state to acquire the glock in
1629 * @flags: modifier flags for the aquisition
1630 *
1631 * Returns: errno
1632 */
1633
1634void gfs2_glock_prefetch_num(struct gfs2_sbd *sdp, uint64_t number,
1635 struct gfs2_glock_operations *glops,
1636 unsigned int state, int flags)
1637{
1638 struct gfs2_glock *gl;
1639 int error;
1640
1641 if (atomic_read(&sdp->sd_reclaim_count) <
1642 gfs2_tune_get(sdp, gt_reclaim_limit)) {
1643 error = gfs2_glock_get(sdp, number, glops, CREATE, &gl);
1644 if (!error) {
1645 gfs2_glock_prefetch(gl, state, flags);
1646 gfs2_glock_put(gl);
1647 }
1648 }
1649}
1650
1651/**
1652 * gfs2_lvb_hold - attach a LVB from a glock
1653 * @gl: The glock in question
1654 *
1655 */
1656
1657int gfs2_lvb_hold(struct gfs2_glock *gl)
1658{
1659 int error;
1660
1661 gfs2_glmutex_lock(gl);
1662
1663 if (!atomic_read(&gl->gl_lvb_count)) {
1664 error = gfs2_lm_hold_lvb(gl->gl_sbd, gl->gl_lock, &gl->gl_lvb);
1665 if (error) {
1666 gfs2_glmutex_unlock(gl);
1667 return error;
1668 }
1669 gfs2_glock_hold(gl);
1670 }
1671 atomic_inc(&gl->gl_lvb_count);
1672
1673 gfs2_glmutex_unlock(gl);
1674
1675 return 0;
1676}
1677
1678/**
1679 * gfs2_lvb_unhold - detach a LVB from a glock
1680 * @gl: The glock in question
1681 *
1682 */
1683
1684void gfs2_lvb_unhold(struct gfs2_glock *gl)
1685{
1686 gfs2_glock_hold(gl);
1687 gfs2_glmutex_lock(gl);
1688
1689 gfs2_assert(gl->gl_sbd, atomic_read(&gl->gl_lvb_count) > 0);
1690 if (atomic_dec_and_test(&gl->gl_lvb_count)) {
1691 gfs2_lm_unhold_lvb(gl->gl_sbd, gl->gl_lock, gl->gl_lvb);
1692 gl->gl_lvb = NULL;
1693 gfs2_glock_put(gl);
1694 }
1695
1696 gfs2_glmutex_unlock(gl);
1697 gfs2_glock_put(gl);
1698}
1699
1700void gfs2_lvb_sync(struct gfs2_glock *gl)
1701{
1702 gfs2_glmutex_lock(gl);
1703
1704 gfs2_assert(gl->gl_sbd, atomic_read(&gl->gl_lvb_count));
1705 if (!gfs2_assert_warn(gl->gl_sbd, gfs2_glock_is_held_excl(gl)))
1706 gfs2_lm_sync_lvb(gl->gl_sbd, gl->gl_lock, gl->gl_lvb);
1707
1708 gfs2_glmutex_unlock(gl);
1709}
1710
1711static void blocking_cb(struct gfs2_sbd *sdp, struct lm_lockname *name,
1712 unsigned int state)
1713{
1714 struct gfs2_glock *gl;
1715
1716 gl = gfs2_glock_find(sdp, name);
1717 if (!gl)
1718 return;
1719
1720 if (gl->gl_ops->go_callback)
1721 gl->gl_ops->go_callback(gl, state);
1722 handle_callback(gl, state);
1723
1724 spin_lock(&gl->gl_spin);
1725 run_queue(gl);
1726 spin_unlock(&gl->gl_spin);
1727
1728 gfs2_glock_put(gl);
1729}
1730
1731/**
1732 * gfs2_glock_cb - Callback used by locking module
1733 * @fsdata: Pointer to the superblock
1734 * @type: Type of callback
1735 * @data: Type dependent data pointer
1736 *
1737 * Called by the locking module when it wants to tell us something.
1738 * Either we need to drop a lock, one of our ASYNC requests completed, or
1739 * a journal from another client needs to be recovered.
1740 */
1741
1742void gfs2_glock_cb(lm_fsdata_t *fsdata, unsigned int type, void *data)
1743{
1744 struct gfs2_sbd *sdp = (struct gfs2_sbd *)fsdata;
1745
David Teiglandb3b94fa2006-01-16 16:50:04 +00001746 switch (type) {
1747 case LM_CB_NEED_E:
David Teiglande7f5c012006-04-27 11:25:45 -04001748 blocking_cb(sdp, data, LM_ST_UNLOCKED);
David Teiglandb3b94fa2006-01-16 16:50:04 +00001749 return;
1750
1751 case LM_CB_NEED_D:
David Teiglande7f5c012006-04-27 11:25:45 -04001752 blocking_cb(sdp, data, LM_ST_DEFERRED);
David Teiglandb3b94fa2006-01-16 16:50:04 +00001753 return;
1754
1755 case LM_CB_NEED_S:
David Teiglande7f5c012006-04-27 11:25:45 -04001756 blocking_cb(sdp, data, LM_ST_SHARED);
David Teiglandb3b94fa2006-01-16 16:50:04 +00001757 return;
1758
1759 case LM_CB_ASYNC: {
David Teiglande7f5c012006-04-27 11:25:45 -04001760 struct lm_async_cb *async = data;
David Teiglandb3b94fa2006-01-16 16:50:04 +00001761 struct gfs2_glock *gl;
1762
1763 gl = gfs2_glock_find(sdp, &async->lc_name);
1764 if (gfs2_assert_warn(sdp, gl))
1765 return;
1766 if (!gfs2_assert_warn(sdp, gl->gl_req_bh))
1767 gl->gl_req_bh(gl, async->lc_ret);
1768 gfs2_glock_put(gl);
David Teiglandb3b94fa2006-01-16 16:50:04 +00001769 return;
1770 }
1771
1772 case LM_CB_NEED_RECOVERY:
1773 gfs2_jdesc_make_dirty(sdp, *(unsigned int *)data);
1774 if (sdp->sd_recoverd_process)
1775 wake_up_process(sdp->sd_recoverd_process);
1776 return;
1777
1778 case LM_CB_DROPLOCKS:
1779 gfs2_gl_hash_clear(sdp, NO_WAIT);
1780 gfs2_quota_scan(sdp);
1781 return;
1782
1783 default:
1784 gfs2_assert_warn(sdp, 0);
1785 return;
1786 }
1787}
1788
1789/**
1790 * gfs2_try_toss_inode - try to remove a particular inode struct from cache
1791 * sdp: the filesystem
1792 * inum: the inode number
1793 *
1794 */
1795
1796void gfs2_try_toss_inode(struct gfs2_sbd *sdp, struct gfs2_inum *inum)
1797{
1798 struct gfs2_glock *gl;
1799 struct gfs2_inode *ip;
1800 int error;
1801
1802 error = gfs2_glock_get(sdp, inum->no_addr, &gfs2_inode_glops,
1803 NO_CREATE, &gl);
1804 if (error || !gl)
1805 return;
1806
1807 if (!gfs2_glmutex_trylock(gl))
1808 goto out;
1809
Steven Whitehouse5c676f62006-02-27 17:23:27 -05001810 ip = gl->gl_object;
David Teiglandb3b94fa2006-01-16 16:50:04 +00001811 if (!ip)
1812 goto out_unlock;
1813
1814 if (atomic_read(&ip->i_count))
1815 goto out_unlock;
1816
1817 gfs2_inode_destroy(ip);
1818
1819 out_unlock:
1820 gfs2_glmutex_unlock(gl);
1821
1822 out:
1823 gfs2_glock_put(gl);
1824}
1825
1826/**
1827 * gfs2_iopen_go_callback - Try to kick the inode/vnode associated with an
1828 * iopen glock from memory
1829 * @io_gl: the iopen glock
1830 * @state: the state into which the glock should be put
1831 *
1832 */
1833
1834void gfs2_iopen_go_callback(struct gfs2_glock *io_gl, unsigned int state)
1835{
1836 struct gfs2_glock *i_gl;
1837
1838 if (state != LM_ST_UNLOCKED)
1839 return;
1840
1841 spin_lock(&io_gl->gl_spin);
Steven Whitehouse5c676f62006-02-27 17:23:27 -05001842 i_gl = io_gl->gl_object;
David Teiglandb3b94fa2006-01-16 16:50:04 +00001843 if (i_gl) {
1844 gfs2_glock_hold(i_gl);
1845 spin_unlock(&io_gl->gl_spin);
1846 } else {
1847 spin_unlock(&io_gl->gl_spin);
1848 return;
1849 }
1850
1851 if (gfs2_glmutex_trylock(i_gl)) {
Steven Whitehouse5c676f62006-02-27 17:23:27 -05001852 struct gfs2_inode *ip = i_gl->gl_object;
David Teiglandb3b94fa2006-01-16 16:50:04 +00001853 if (ip) {
1854 gfs2_try_toss_vnode(ip);
1855 gfs2_glmutex_unlock(i_gl);
1856 gfs2_glock_schedule_for_reclaim(i_gl);
1857 goto out;
1858 }
1859 gfs2_glmutex_unlock(i_gl);
1860 }
1861
1862 out:
1863 gfs2_glock_put(i_gl);
1864}
1865
1866/**
1867 * demote_ok - Check to see if it's ok to unlock a glock
1868 * @gl: the glock
1869 *
1870 * Returns: 1 if it's ok
1871 */
1872
1873static int demote_ok(struct gfs2_glock *gl)
1874{
1875 struct gfs2_sbd *sdp = gl->gl_sbd;
1876 struct gfs2_glock_operations *glops = gl->gl_ops;
1877 int demote = 1;
1878
1879 if (test_bit(GLF_STICKY, &gl->gl_flags))
1880 demote = 0;
1881 else if (test_bit(GLF_PREFETCH, &gl->gl_flags))
1882 demote = time_after_eq(jiffies,
1883 gl->gl_stamp +
1884 gfs2_tune_get(sdp, gt_prefetch_secs) * HZ);
1885 else if (glops->go_demote_ok)
1886 demote = glops->go_demote_ok(gl);
1887
1888 return demote;
1889}
1890
1891/**
1892 * gfs2_glock_schedule_for_reclaim - Add a glock to the reclaim list
1893 * @gl: the glock
1894 *
1895 */
1896
1897void gfs2_glock_schedule_for_reclaim(struct gfs2_glock *gl)
1898{
1899 struct gfs2_sbd *sdp = gl->gl_sbd;
1900
1901 spin_lock(&sdp->sd_reclaim_lock);
1902 if (list_empty(&gl->gl_reclaim)) {
1903 gfs2_glock_hold(gl);
1904 list_add(&gl->gl_reclaim, &sdp->sd_reclaim_list);
1905 atomic_inc(&sdp->sd_reclaim_count);
1906 }
1907 spin_unlock(&sdp->sd_reclaim_lock);
1908
1909 wake_up(&sdp->sd_reclaim_wq);
1910}
1911
1912/**
1913 * gfs2_reclaim_glock - process the next glock on the filesystem's reclaim list
1914 * @sdp: the filesystem
1915 *
1916 * Called from gfs2_glockd() glock reclaim daemon, or when promoting a
1917 * different glock and we notice that there are a lot of glocks in the
1918 * reclaim list.
1919 *
1920 */
1921
1922void gfs2_reclaim_glock(struct gfs2_sbd *sdp)
1923{
1924 struct gfs2_glock *gl;
1925
1926 spin_lock(&sdp->sd_reclaim_lock);
1927 if (list_empty(&sdp->sd_reclaim_list)) {
1928 spin_unlock(&sdp->sd_reclaim_lock);
1929 return;
1930 }
1931 gl = list_entry(sdp->sd_reclaim_list.next,
1932 struct gfs2_glock, gl_reclaim);
1933 list_del_init(&gl->gl_reclaim);
1934 spin_unlock(&sdp->sd_reclaim_lock);
1935
1936 atomic_dec(&sdp->sd_reclaim_count);
1937 atomic_inc(&sdp->sd_reclaimed);
1938
1939 if (gfs2_glmutex_trylock(gl)) {
1940 if (gl->gl_ops == &gfs2_inode_glops) {
Steven Whitehouse5c676f62006-02-27 17:23:27 -05001941 struct gfs2_inode *ip = gl->gl_object;
David Teiglandb3b94fa2006-01-16 16:50:04 +00001942 if (ip && !atomic_read(&ip->i_count))
1943 gfs2_inode_destroy(ip);
1944 }
1945 if (queue_empty(gl, &gl->gl_holders) &&
1946 gl->gl_state != LM_ST_UNLOCKED &&
1947 demote_ok(gl))
1948 handle_callback(gl, LM_ST_UNLOCKED);
1949 gfs2_glmutex_unlock(gl);
1950 }
1951
1952 gfs2_glock_put(gl);
1953}
1954
1955/**
1956 * examine_bucket - Call a function for glock in a hash bucket
1957 * @examiner: the function
1958 * @sdp: the filesystem
1959 * @bucket: the bucket
1960 *
1961 * Returns: 1 if the bucket has entries
1962 */
1963
1964static int examine_bucket(glock_examiner examiner, struct gfs2_sbd *sdp,
1965 struct gfs2_gl_hash_bucket *bucket)
1966{
1967 struct glock_plug plug;
1968 struct list_head *tmp;
1969 struct gfs2_glock *gl;
1970 int entries;
1971
1972 /* Add "plug" to end of bucket list, work back up list from there */
1973 memset(&plug.gl_flags, 0, sizeof(unsigned long));
1974 set_bit(GLF_PLUG, &plug.gl_flags);
1975
1976 write_lock(&bucket->hb_lock);
1977 list_add(&plug.gl_list, &bucket->hb_list);
1978 write_unlock(&bucket->hb_lock);
1979
1980 for (;;) {
1981 write_lock(&bucket->hb_lock);
1982
1983 for (;;) {
1984 tmp = plug.gl_list.next;
1985
1986 if (tmp == &bucket->hb_list) {
1987 list_del(&plug.gl_list);
1988 entries = !list_empty(&bucket->hb_list);
1989 write_unlock(&bucket->hb_lock);
1990 return entries;
1991 }
1992 gl = list_entry(tmp, struct gfs2_glock, gl_list);
1993
1994 /* Move plug up list */
1995 list_move(&plug.gl_list, &gl->gl_list);
1996
1997 if (test_bit(GLF_PLUG, &gl->gl_flags))
1998 continue;
1999
2000 /* examiner() must glock_put() */
2001 gfs2_glock_hold(gl);
2002
2003 break;
2004 }
2005
2006 write_unlock(&bucket->hb_lock);
2007
2008 examiner(gl);
2009 }
2010}
2011
2012/**
2013 * scan_glock - look at a glock and see if we can reclaim it
2014 * @gl: the glock to look at
2015 *
2016 */
2017
2018static void scan_glock(struct gfs2_glock *gl)
2019{
2020 if (gfs2_glmutex_trylock(gl)) {
2021 if (gl->gl_ops == &gfs2_inode_glops) {
Steven Whitehouse5c676f62006-02-27 17:23:27 -05002022 struct gfs2_inode *ip = gl->gl_object;
David Teiglandb3b94fa2006-01-16 16:50:04 +00002023 if (ip && !atomic_read(&ip->i_count))
2024 goto out_schedule;
2025 }
2026 if (queue_empty(gl, &gl->gl_holders) &&
2027 gl->gl_state != LM_ST_UNLOCKED &&
2028 demote_ok(gl))
2029 goto out_schedule;
2030
2031 gfs2_glmutex_unlock(gl);
2032 }
2033
2034 gfs2_glock_put(gl);
2035
2036 return;
2037
2038 out_schedule:
2039 gfs2_glmutex_unlock(gl);
2040 gfs2_glock_schedule_for_reclaim(gl);
2041 gfs2_glock_put(gl);
2042}
2043
2044/**
2045 * gfs2_scand_internal - Look for glocks and inodes to toss from memory
2046 * @sdp: the filesystem
2047 *
2048 */
2049
2050void gfs2_scand_internal(struct gfs2_sbd *sdp)
2051{
2052 unsigned int x;
2053
2054 for (x = 0; x < GFS2_GL_HASH_SIZE; x++) {
2055 examine_bucket(scan_glock, sdp, &sdp->sd_gl_hash[x]);
2056 cond_resched();
2057 }
2058}
2059
2060/**
2061 * clear_glock - look at a glock and see if we can free it from glock cache
2062 * @gl: the glock to look at
2063 *
2064 */
2065
2066static void clear_glock(struct gfs2_glock *gl)
2067{
2068 struct gfs2_sbd *sdp = gl->gl_sbd;
2069 int released;
2070
2071 spin_lock(&sdp->sd_reclaim_lock);
2072 if (!list_empty(&gl->gl_reclaim)) {
2073 list_del_init(&gl->gl_reclaim);
2074 atomic_dec(&sdp->sd_reclaim_count);
Steven Whitehouse190562b2006-04-20 16:57:23 -04002075 spin_unlock(&sdp->sd_reclaim_lock);
David Teiglandb3b94fa2006-01-16 16:50:04 +00002076 released = gfs2_glock_put(gl);
2077 gfs2_assert(sdp, !released);
Steven Whitehouse190562b2006-04-20 16:57:23 -04002078 } else {
2079 spin_unlock(&sdp->sd_reclaim_lock);
David Teiglandb3b94fa2006-01-16 16:50:04 +00002080 }
David Teiglandb3b94fa2006-01-16 16:50:04 +00002081
2082 if (gfs2_glmutex_trylock(gl)) {
2083 if (gl->gl_ops == &gfs2_inode_glops) {
Steven Whitehouse5c676f62006-02-27 17:23:27 -05002084 struct gfs2_inode *ip = gl->gl_object;
David Teiglandb3b94fa2006-01-16 16:50:04 +00002085 if (ip && !atomic_read(&ip->i_count))
2086 gfs2_inode_destroy(ip);
2087 }
2088 if (queue_empty(gl, &gl->gl_holders) &&
2089 gl->gl_state != LM_ST_UNLOCKED)
2090 handle_callback(gl, LM_ST_UNLOCKED);
2091
2092 gfs2_glmutex_unlock(gl);
2093 }
2094
2095 gfs2_glock_put(gl);
2096}
2097
2098/**
2099 * gfs2_gl_hash_clear - Empty out the glock hash table
2100 * @sdp: the filesystem
2101 * @wait: wait until it's all gone
2102 *
2103 * Called when unmounting the filesystem, or when inter-node lock manager
2104 * requests DROPLOCKS because it is running out of capacity.
2105 */
2106
2107void gfs2_gl_hash_clear(struct gfs2_sbd *sdp, int wait)
2108{
2109 unsigned long t;
2110 unsigned int x;
2111 int cont;
2112
2113 t = jiffies;
2114
2115 for (;;) {
2116 cont = 0;
2117
2118 for (x = 0; x < GFS2_GL_HASH_SIZE; x++)
2119 if (examine_bucket(clear_glock, sdp,
2120 &sdp->sd_gl_hash[x]))
2121 cont = 1;
2122
2123 if (!wait || !cont)
2124 break;
2125
2126 if (time_after_eq(jiffies,
2127 t + gfs2_tune_get(sdp, gt_stall_secs) * HZ)) {
2128 fs_warn(sdp, "Unmount seems to be stalled. "
2129 "Dumping lock state...\n");
2130 gfs2_dump_lockstate(sdp);
2131 t = jiffies;
2132 }
2133
2134 /* invalidate_inodes() requires that the sb inodes list
2135 not change, but an async completion callback for an
2136 unlock can occur which does glock_put() which
2137 can call iput() which will change the sb inodes list.
2138 invalidate_inodes_mutex prevents glock_put()'s during
2139 an invalidate_inodes() */
2140
Steven Whitehousef55ab262006-02-21 12:51:39 +00002141 mutex_lock(&sdp->sd_invalidate_inodes_mutex);
David Teiglandb3b94fa2006-01-16 16:50:04 +00002142 invalidate_inodes(sdp->sd_vfs);
Steven Whitehousef55ab262006-02-21 12:51:39 +00002143 mutex_unlock(&sdp->sd_invalidate_inodes_mutex);
David Teiglandb3b94fa2006-01-16 16:50:04 +00002144 yield();
2145 }
2146}
2147
2148/*
2149 * Diagnostic routines to help debug distributed deadlock
2150 */
2151
2152/**
2153 * dump_holder - print information about a glock holder
2154 * @str: a string naming the type of holder
2155 * @gh: the glock holder
2156 *
2157 * Returns: 0 on success, -ENOBUFS when we run out of space
2158 */
2159
2160static int dump_holder(char *str, struct gfs2_holder *gh)
2161{
2162 unsigned int x;
2163 int error = -ENOBUFS;
2164
Steven Whitehoused92a8d42006-02-27 10:57:14 -05002165 printk(KERN_INFO " %s\n", str);
2166 printk(KERN_INFO " owner = %ld\n",
David Teiglandb3b94fa2006-01-16 16:50:04 +00002167 (gh->gh_owner) ? (long)gh->gh_owner->pid : -1);
Steven Whitehoused92a8d42006-02-27 10:57:14 -05002168 printk(KERN_INFO " gh_state = %u\n", gh->gh_state);
2169 printk(KERN_INFO " gh_flags =");
David Teiglandb3b94fa2006-01-16 16:50:04 +00002170 for (x = 0; x < 32; x++)
2171 if (gh->gh_flags & (1 << x))
2172 printk(" %u", x);
2173 printk(" \n");
Steven Whitehoused92a8d42006-02-27 10:57:14 -05002174 printk(KERN_INFO " error = %d\n", gh->gh_error);
2175 printk(KERN_INFO " gh_iflags =");
David Teiglandb3b94fa2006-01-16 16:50:04 +00002176 for (x = 0; x < 32; x++)
2177 if (test_bit(x, &gh->gh_iflags))
2178 printk(" %u", x);
2179 printk(" \n");
Steven Whitehoused0dc80d2006-03-29 14:36:49 -05002180 print_symbol(KERN_INFO " initialized at: %s\n", gh->gh_ip);
David Teiglandb3b94fa2006-01-16 16:50:04 +00002181
2182 error = 0;
2183
2184 return error;
2185}
2186
2187/**
2188 * dump_inode - print information about an inode
2189 * @ip: the inode
2190 *
2191 * Returns: 0 on success, -ENOBUFS when we run out of space
2192 */
2193
2194static int dump_inode(struct gfs2_inode *ip)
2195{
2196 unsigned int x;
2197 int error = -ENOBUFS;
2198
Steven Whitehoused92a8d42006-02-27 10:57:14 -05002199 printk(KERN_INFO " Inode:\n");
2200 printk(KERN_INFO " num = %llu %llu\n",
David Teiglandb3b94fa2006-01-16 16:50:04 +00002201 ip->i_num.no_formal_ino, ip->i_num.no_addr);
Steven Whitehoused92a8d42006-02-27 10:57:14 -05002202 printk(KERN_INFO " type = %u\n", IF2DT(ip->i_di.di_mode));
2203 printk(KERN_INFO " i_count = %d\n", atomic_read(&ip->i_count));
2204 printk(KERN_INFO " i_flags =");
David Teiglandb3b94fa2006-01-16 16:50:04 +00002205 for (x = 0; x < 32; x++)
2206 if (test_bit(x, &ip->i_flags))
2207 printk(" %u", x);
2208 printk(" \n");
Steven Whitehoused92a8d42006-02-27 10:57:14 -05002209 printk(KERN_INFO " vnode = %s\n", (ip->i_vnode) ? "yes" : "no");
David Teiglandb3b94fa2006-01-16 16:50:04 +00002210
2211 error = 0;
2212
2213 return error;
2214}
2215
2216/**
2217 * dump_glock - print information about a glock
2218 * @gl: the glock
2219 * @count: where we are in the buffer
2220 *
2221 * Returns: 0 on success, -ENOBUFS when we run out of space
2222 */
2223
2224static int dump_glock(struct gfs2_glock *gl)
2225{
2226 struct gfs2_holder *gh;
2227 unsigned int x;
2228 int error = -ENOBUFS;
2229
2230 spin_lock(&gl->gl_spin);
2231
Steven Whitehoused92a8d42006-02-27 10:57:14 -05002232 printk(KERN_INFO "Glock (%u, %llu)\n",
David Teiglandb3b94fa2006-01-16 16:50:04 +00002233 gl->gl_name.ln_type,
2234 gl->gl_name.ln_number);
Steven Whitehoused92a8d42006-02-27 10:57:14 -05002235 printk(KERN_INFO " gl_flags =");
David Teiglandb3b94fa2006-01-16 16:50:04 +00002236 for (x = 0; x < 32; x++)
2237 if (test_bit(x, &gl->gl_flags))
2238 printk(" %u", x);
2239 printk(" \n");
Steven Whitehoused92a8d42006-02-27 10:57:14 -05002240 printk(KERN_INFO " gl_ref = %d\n", atomic_read(&gl->gl_ref.refcount));
2241 printk(KERN_INFO " gl_state = %u\n", gl->gl_state);
2242 printk(KERN_INFO " req_gh = %s\n", (gl->gl_req_gh) ? "yes" : "no");
2243 printk(KERN_INFO " req_bh = %s\n", (gl->gl_req_bh) ? "yes" : "no");
2244 printk(KERN_INFO " lvb_count = %d\n", atomic_read(&gl->gl_lvb_count));
2245 printk(KERN_INFO " object = %s\n", (gl->gl_object) ? "yes" : "no");
2246 printk(KERN_INFO " le = %s\n",
David Teiglandb3b94fa2006-01-16 16:50:04 +00002247 (list_empty(&gl->gl_le.le_list)) ? "no" : "yes");
Steven Whitehoused92a8d42006-02-27 10:57:14 -05002248 printk(KERN_INFO " reclaim = %s\n",
David Teiglandb3b94fa2006-01-16 16:50:04 +00002249 (list_empty(&gl->gl_reclaim)) ? "no" : "yes");
2250 if (gl->gl_aspace)
Steven Whitehoused92a8d42006-02-27 10:57:14 -05002251 printk(KERN_INFO " aspace = %lu\n",
David Teiglandb3b94fa2006-01-16 16:50:04 +00002252 gl->gl_aspace->i_mapping->nrpages);
2253 else
Steven Whitehoused92a8d42006-02-27 10:57:14 -05002254 printk(KERN_INFO " aspace = no\n");
2255 printk(KERN_INFO " ail = %d\n", atomic_read(&gl->gl_ail_count));
David Teiglandb3b94fa2006-01-16 16:50:04 +00002256 if (gl->gl_req_gh) {
2257 error = dump_holder("Request", gl->gl_req_gh);
2258 if (error)
2259 goto out;
2260 }
2261 list_for_each_entry(gh, &gl->gl_holders, gh_list) {
2262 error = dump_holder("Holder", gh);
2263 if (error)
2264 goto out;
2265 }
2266 list_for_each_entry(gh, &gl->gl_waiters1, gh_list) {
2267 error = dump_holder("Waiter1", gh);
2268 if (error)
2269 goto out;
2270 }
2271 list_for_each_entry(gh, &gl->gl_waiters2, gh_list) {
2272 error = dump_holder("Waiter2", gh);
2273 if (error)
2274 goto out;
2275 }
2276 list_for_each_entry(gh, &gl->gl_waiters3, gh_list) {
2277 error = dump_holder("Waiter3", gh);
2278 if (error)
2279 goto out;
2280 }
Steven Whitehouse5c676f62006-02-27 17:23:27 -05002281 if (gl->gl_ops == &gfs2_inode_glops && gl->gl_object) {
David Teiglandb3b94fa2006-01-16 16:50:04 +00002282 if (!test_bit(GLF_LOCK, &gl->gl_flags) &&
2283 list_empty(&gl->gl_holders)) {
Steven Whitehouse5c676f62006-02-27 17:23:27 -05002284 error = dump_inode(gl->gl_object);
David Teiglandb3b94fa2006-01-16 16:50:04 +00002285 if (error)
2286 goto out;
2287 } else {
2288 error = -ENOBUFS;
Steven Whitehoused92a8d42006-02-27 10:57:14 -05002289 printk(KERN_INFO " Inode: busy\n");
David Teiglandb3b94fa2006-01-16 16:50:04 +00002290 }
2291 }
2292
2293 error = 0;
2294
2295 out:
2296 spin_unlock(&gl->gl_spin);
2297
2298 return error;
2299}
2300
2301/**
2302 * gfs2_dump_lockstate - print out the current lockstate
2303 * @sdp: the filesystem
2304 * @ub: the buffer to copy the information into
2305 *
2306 * If @ub is NULL, dump the lockstate to the console.
2307 *
2308 */
2309
2310int gfs2_dump_lockstate(struct gfs2_sbd *sdp)
2311{
2312 struct gfs2_gl_hash_bucket *bucket;
2313 struct gfs2_glock *gl;
2314 unsigned int x;
2315 int error = 0;
2316
2317 for (x = 0; x < GFS2_GL_HASH_SIZE; x++) {
2318 bucket = &sdp->sd_gl_hash[x];
2319
2320 read_lock(&bucket->hb_lock);
2321
2322 list_for_each_entry(gl, &bucket->hb_list, gl_list) {
2323 if (test_bit(GLF_PLUG, &gl->gl_flags))
2324 continue;
2325
2326 error = dump_glock(gl);
2327 if (error)
2328 break;
2329 }
2330
2331 read_unlock(&bucket->hb_lock);
2332
2333 if (error)
2334 break;
2335 }
2336
2337
2338 return error;
2339}
2340