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mach-ux500: update SoC and board IRQ handling
[linux-2.6/linux-acpi-2.6/ibm-acpi-2.6.git] / fs / gfs2 / glock.c
bloba2a6abbccc070194c94dfeb37913291fb57be61a
1 /*
2 * Copyright (C) Sistina Software, Inc. 1997-2003 All rights reserved.
3 * Copyright (C) 2004-2008 Red Hat, Inc. All rights reserved.
4 *
5 * This copyrighted material is made available to anyone wishing to use,
6 * modify, copy, or redistribute it subject to the terms and conditions
7 * of the GNU General Public License version 2.
8 */
9
10 #include <linux/sched.h>
11 #include <linux/slab.h>
12 #include <linux/spinlock.h>
13 #include <linux/buffer_head.h>
14 #include <linux/delay.h>
15 #include <linux/sort.h>
16 #include <linux/jhash.h>
17 #include <linux/kallsyms.h>
18 #include <linux/gfs2_ondisk.h>
19 #include <linux/list.h>
20 #include <linux/wait.h>
21 #include <linux/module.h>
22 #include <asm/uaccess.h>
23 #include <linux/seq_file.h>
24 #include <linux/debugfs.h>
25 #include <linux/kthread.h>
26 #include <linux/freezer.h>
27 #include <linux/workqueue.h>
28 #include <linux/jiffies.h>
29 #include <linux/rcupdate.h>
30 #include <linux/rculist_bl.h>
31 #include <linux/bit_spinlock.h>
32
33 #include "gfs2.h"
34 #include "incore.h"
35 #include "glock.h"
36 #include "glops.h"
37 #include "inode.h"
38 #include "lops.h"
39 #include "meta_io.h"
40 #include "quota.h"
41 #include "super.h"
42 #include "util.h"
43 #include "bmap.h"
44 #define CREATE_TRACE_POINTS
45 #include "trace_gfs2.h"
46
47 struct gfs2_glock_iter {
48 int hash; /* hash bucket index */
49 struct gfs2_sbd *sdp; /* incore superblock */
50 struct gfs2_glock *gl; /* current glock struct */
51 char string[512]; /* scratch space */
52 };
53
54 typedef void (*glock_examiner) (struct gfs2_glock * gl);
55
56 static int __dump_glock(struct seq_file *seq, const struct gfs2_glock *gl);
57 #define GLOCK_BUG_ON(gl,x) do { if (unlikely(x)) { __dump_glock(NULL, gl); BUG(); } } while(0)
58 static void do_xmote(struct gfs2_glock *gl, struct gfs2_holder *gh, unsigned int target);
59
60 static struct dentry *gfs2_root;
61 static struct workqueue_struct *glock_workqueue;
62 struct workqueue_struct *gfs2_delete_workqueue;
63 static LIST_HEAD(lru_list);
64 static atomic_t lru_count = ATOMIC_INIT(0);
65 static DEFINE_SPINLOCK(lru_lock);
66
67 #define GFS2_GL_HASH_SHIFT 15
68 #define GFS2_GL_HASH_SIZE (1 << GFS2_GL_HASH_SHIFT)
69 #define GFS2_GL_HASH_MASK (GFS2_GL_HASH_SIZE - 1)
70
71 static struct hlist_bl_head gl_hash_table[GFS2_GL_HASH_SIZE];
72 static struct dentry *gfs2_root;
73
74 /**
75 * gl_hash() - Turn glock number into hash bucket number
76 * @lock: The glock number
77 *
78 * Returns: The number of the corresponding hash bucket
79 */
80
81 static unsigned int gl_hash(const struct gfs2_sbd *sdp,
82 const struct lm_lockname *name)
83 {
84 unsigned int h;
85
86 h = jhash(&name->ln_number, sizeof(u64), 0);
87 h = jhash(&name->ln_type, sizeof(unsigned int), h);
88 h = jhash(&sdp, sizeof(struct gfs2_sbd *), h);
89 h &= GFS2_GL_HASH_MASK;
90
91 return h;
92 }
93
94 static inline void spin_lock_bucket(unsigned int hash)
95 {
96 hlist_bl_lock(&gl_hash_table[hash]);
97 }
98
99 static inline void spin_unlock_bucket(unsigned int hash)
100 {
101 hlist_bl_unlock(&gl_hash_table[hash]);
102 }
103
104 static void gfs2_glock_dealloc(struct rcu_head *rcu)
105 {
106 struct gfs2_glock *gl = container_of(rcu, struct gfs2_glock, gl_rcu);
107
108 if (gl->gl_ops->go_flags & GLOF_ASPACE)
109 kmem_cache_free(gfs2_glock_aspace_cachep, gl);
110 else
111 kmem_cache_free(gfs2_glock_cachep, gl);
112 }
113
114 void gfs2_glock_free(struct gfs2_glock *gl)
115 {
116 struct gfs2_sbd *sdp = gl->gl_sbd;
117
118 call_rcu(&gl->gl_rcu, gfs2_glock_dealloc);
119 if (atomic_dec_and_test(&sdp->sd_glock_disposal))
120 wake_up(&sdp->sd_glock_wait);
121 }
122
123 /**
124 * gfs2_glock_hold() - increment reference count on glock
125 * @gl: The glock to hold
126 *
127 */
128
129 void gfs2_glock_hold(struct gfs2_glock *gl)
130 {
131 GLOCK_BUG_ON(gl, atomic_read(&gl->gl_ref) == 0);
132 atomic_inc(&gl->gl_ref);
133 }
134
135 /**
136 * demote_ok - Check to see if it's ok to unlock a glock
137 * @gl: the glock
138 *
139 * Returns: 1 if it's ok
140 */
141
142 static int demote_ok(const struct gfs2_glock *gl)
143 {
144 const struct gfs2_glock_operations *glops = gl->gl_ops;
145
146 if (gl->gl_state == LM_ST_UNLOCKED)
147 return 0;
148 if (!list_empty(&gl->gl_holders))
149 return 0;
150 if (glops->go_demote_ok)
151 return glops->go_demote_ok(gl);
152 return 1;
153 }
154
155
156 void gfs2_glock_add_to_lru(struct gfs2_glock *gl)
157 {
158 spin_lock(&lru_lock);
159
160 if (!list_empty(&gl->gl_lru))
161 list_del_init(&gl->gl_lru);
162 else
163 atomic_inc(&lru_count);
164
165 list_add_tail(&gl->gl_lru, &lru_list);
166 set_bit(GLF_LRU, &gl->gl_flags);
167 spin_unlock(&lru_lock);
168 }
169
170 static void gfs2_glock_remove_from_lru(struct gfs2_glock *gl)
171 {
172 spin_lock(&lru_lock);
173 if (!list_empty(&gl->gl_lru)) {
174 list_del_init(&gl->gl_lru);
175 atomic_dec(&lru_count);
176 clear_bit(GLF_LRU, &gl->gl_flags);
177 }
178 spin_unlock(&lru_lock);
179 }
180
181 /**
182 * __gfs2_glock_schedule_for_reclaim - Add a glock to the reclaim list
183 * @gl: the glock
184 *
185 * If the glock is demotable, then we add it (or move it) to the end
186 * of the glock LRU list.
187 */
188
189 static void __gfs2_glock_schedule_for_reclaim(struct gfs2_glock *gl)
190 {
191 if (demote_ok(gl))
192 gfs2_glock_add_to_lru(gl);
193 }
194
195 /**
196 * gfs2_glock_put_nolock() - Decrement reference count on glock
197 * @gl: The glock to put
198 *
199 * This function should only be used if the caller has its own reference
200 * to the glock, in addition to the one it is dropping.
201 */
202
203 void gfs2_glock_put_nolock(struct gfs2_glock *gl)
204 {
205 if (atomic_dec_and_test(&gl->gl_ref))
206 GLOCK_BUG_ON(gl, 1);
207 }
208
209 /**
210 * gfs2_glock_put() - Decrement reference count on glock
211 * @gl: The glock to put
212 *
213 */
214
215 void gfs2_glock_put(struct gfs2_glock *gl)
216 {
217 struct gfs2_sbd *sdp = gl->gl_sbd;
218 struct address_space *mapping = gfs2_glock2aspace(gl);
219
220 if (atomic_dec_and_test(&gl->gl_ref)) {
221 spin_lock_bucket(gl->gl_hash);
222 hlist_bl_del_rcu(&gl->gl_list);
223 spin_unlock_bucket(gl->gl_hash);
224 gfs2_glock_remove_from_lru(gl);
225 GLOCK_BUG_ON(gl, !list_empty(&gl->gl_holders));
226 GLOCK_BUG_ON(gl, mapping && mapping->nrpages);
227 trace_gfs2_glock_put(gl);
228 sdp->sd_lockstruct.ls_ops->lm_put_lock(gl);
229 }
230 }
231
232 /**
233 * search_bucket() - Find struct gfs2_glock by lock number
234 * @bucket: the bucket to search
235 * @name: The lock name
236 *
237 * Returns: NULL, or the struct gfs2_glock with the requested number
238 */
239
240 static struct gfs2_glock *search_bucket(unsigned int hash,
241 const struct gfs2_sbd *sdp,
242 const struct lm_lockname *name)
243 {
244 struct gfs2_glock *gl;
245 struct hlist_bl_node *h;
246
247 hlist_bl_for_each_entry_rcu(gl, h, &gl_hash_table[hash], gl_list) {
248 if (!lm_name_equal(&gl->gl_name, name))
249 continue;
250 if (gl->gl_sbd != sdp)
251 continue;
252 if (atomic_inc_not_zero(&gl->gl_ref))
253 return gl;
254 }
255
256 return NULL;
257 }
258
259 /**
260 * may_grant - check if its ok to grant a new lock
261 * @gl: The glock
262 * @gh: The lock request which we wish to grant
263 *
264 * Returns: true if its ok to grant the lock
265 */
266
267 static inline int may_grant(const struct gfs2_glock *gl, const struct gfs2_holder *gh)
268 {
269 const struct gfs2_holder *gh_head = list_entry(gl->gl_holders.next, const struct gfs2_holder, gh_list);
270 if ((gh->gh_state == LM_ST_EXCLUSIVE ||
271 gh_head->gh_state == LM_ST_EXCLUSIVE) && gh != gh_head)
272 return 0;
273 if (gl->gl_state == gh->gh_state)
274 return 1;
275 if (gh->gh_flags & GL_EXACT)
276 return 0;
277 if (gl->gl_state == LM_ST_EXCLUSIVE) {
278 if (gh->gh_state == LM_ST_SHARED && gh_head->gh_state == LM_ST_SHARED)
279 return 1;
280 if (gh->gh_state == LM_ST_DEFERRED && gh_head->gh_state == LM_ST_DEFERRED)
281 return 1;
282 }
283 if (gl->gl_state != LM_ST_UNLOCKED && (gh->gh_flags & LM_FLAG_ANY))
284 return 1;
285 return 0;
286 }
287
288 static void gfs2_holder_wake(struct gfs2_holder *gh)
289 {
290 clear_bit(HIF_WAIT, &gh->gh_iflags);
291 smp_mb__after_clear_bit();
292 wake_up_bit(&gh->gh_iflags, HIF_WAIT);
293 }
294
295 /**
296 * do_error - Something unexpected has happened during a lock request
297 *
298 */
299
300 static inline void do_error(struct gfs2_glock *gl, const int ret)
301 {
302 struct gfs2_holder *gh, *tmp;
303
304 list_for_each_entry_safe(gh, tmp, &gl->gl_holders, gh_list) {
305 if (test_bit(HIF_HOLDER, &gh->gh_iflags))
306 continue;
307 if (ret & LM_OUT_ERROR)
308 gh->gh_error = -EIO;
309 else if (gh->gh_flags & (LM_FLAG_TRY | LM_FLAG_TRY_1CB))
310 gh->gh_error = GLR_TRYFAILED;
311 else
312 continue;
313 list_del_init(&gh->gh_list);
314 trace_gfs2_glock_queue(gh, 0);
315 gfs2_holder_wake(gh);
316 }
317 }
318
319 /**
320 * do_promote - promote as many requests as possible on the current queue
321 * @gl: The glock
322 *
323 * Returns: 1 if there is a blocked holder at the head of the list, or 2
324 * if a type specific operation is underway.
325 */
326
327 static int do_promote(struct gfs2_glock *gl)
328 __releases(&gl->gl_spin)
329 __acquires(&gl->gl_spin)
330 {
331 const struct gfs2_glock_operations *glops = gl->gl_ops;
332 struct gfs2_holder *gh, *tmp;
333 int ret;
334
335 restart:
336 list_for_each_entry_safe(gh, tmp, &gl->gl_holders, gh_list) {
337 if (test_bit(HIF_HOLDER, &gh->gh_iflags))
338 continue;
339 if (may_grant(gl, gh)) {
340 if (gh->gh_list.prev == &gl->gl_holders &&
341 glops->go_lock) {
342 spin_unlock(&gl->gl_spin);
343 /* FIXME: eliminate this eventually */
344 ret = glops->go_lock(gh);
345 spin_lock(&gl->gl_spin);
346 if (ret) {
347 if (ret == 1)
348 return 2;
349 gh->gh_error = ret;
350 list_del_init(&gh->gh_list);
351 trace_gfs2_glock_queue(gh, 0);
352 gfs2_holder_wake(gh);
353 goto restart;
354 }
355 set_bit(HIF_HOLDER, &gh->gh_iflags);
356 trace_gfs2_promote(gh, 1);
357 gfs2_holder_wake(gh);
358 goto restart;
359 }
360 set_bit(HIF_HOLDER, &gh->gh_iflags);
361 trace_gfs2_promote(gh, 0);
362 gfs2_holder_wake(gh);
363 continue;
364 }
365 if (gh->gh_list.prev == &gl->gl_holders)
366 return 1;
367 do_error(gl, 0);
368 break;
369 }
370 return 0;
371 }
372
373 /**
374 * find_first_waiter - find the first gh that's waiting for the glock
375 * @gl: the glock
376 */
377
378 static inline struct gfs2_holder *find_first_waiter(const struct gfs2_glock *gl)
379 {
380 struct gfs2_holder *gh;
381
382 list_for_each_entry(gh, &gl->gl_holders, gh_list) {
383 if (!test_bit(HIF_HOLDER, &gh->gh_iflags))
384 return gh;
385 }
386 return NULL;
387 }
388
389 /**
390 * state_change - record that the glock is now in a different state
391 * @gl: the glock
392 * @new_state the new state
393 *
394 */
395
396 static void state_change(struct gfs2_glock *gl, unsigned int new_state)
397 {
398 int held1, held2;
399
400 held1 = (gl->gl_state != LM_ST_UNLOCKED);
401 held2 = (new_state != LM_ST_UNLOCKED);
402
403 if (held1 != held2) {
404 if (held2)
405 gfs2_glock_hold(gl);
406 else
407 gfs2_glock_put_nolock(gl);
408 }
409 if (held1 && held2 && list_empty(&gl->gl_holders))
410 clear_bit(GLF_QUEUED, &gl->gl_flags);
411
412 gl->gl_state = new_state;
413 gl->gl_tchange = jiffies;
414 }
415
416 static void gfs2_demote_wake(struct gfs2_glock *gl)
417 {
418 gl->gl_demote_state = LM_ST_EXCLUSIVE;
419 clear_bit(GLF_DEMOTE, &gl->gl_flags);
420 smp_mb__after_clear_bit();
421 wake_up_bit(&gl->gl_flags, GLF_DEMOTE);
422 }
423
424 /**
425 * finish_xmote - The DLM has replied to one of our lock requests
426 * @gl: The glock
427 * @ret: The status from the DLM
428 *
429 */
430
431 static void finish_xmote(struct gfs2_glock *gl, unsigned int ret)
432 {
433 const struct gfs2_glock_operations *glops = gl->gl_ops;
434 struct gfs2_holder *gh;
435 unsigned state = ret & LM_OUT_ST_MASK;
436 int rv;
437
438 spin_lock(&gl->gl_spin);
439 trace_gfs2_glock_state_change(gl, state);
440 state_change(gl, state);
441 gh = find_first_waiter(gl);
442
443 /* Demote to UN request arrived during demote to SH or DF */
444 if (test_bit(GLF_DEMOTE_IN_PROGRESS, &gl->gl_flags) &&
445 state != LM_ST_UNLOCKED && gl->gl_demote_state == LM_ST_UNLOCKED)
446 gl->gl_target = LM_ST_UNLOCKED;
447
448 /* Check for state != intended state */
449 if (unlikely(state != gl->gl_target)) {
450 if (gh && !test_bit(GLF_DEMOTE_IN_PROGRESS, &gl->gl_flags)) {
451 /* move to back of queue and try next entry */
452 if (ret & LM_OUT_CANCELED) {
453 if ((gh->gh_flags & LM_FLAG_PRIORITY) == 0)
454 list_move_tail(&gh->gh_list, &gl->gl_holders);
455 gh = find_first_waiter(gl);
456 gl->gl_target = gh->gh_state;
457 goto retry;
458 }
459 /* Some error or failed "try lock" - report it */
460 if ((ret & LM_OUT_ERROR) ||
461 (gh->gh_flags & (LM_FLAG_TRY | LM_FLAG_TRY_1CB))) {
462 gl->gl_target = gl->gl_state;
463 do_error(gl, ret);
464 goto out;
465 }
466 }
467 switch(state) {
468 /* Unlocked due to conversion deadlock, try again */
469 case LM_ST_UNLOCKED:
470 retry:
471 do_xmote(gl, gh, gl->gl_target);
472 break;
473 /* Conversion fails, unlock and try again */
474 case LM_ST_SHARED:
475 case LM_ST_DEFERRED:
476 do_xmote(gl, gh, LM_ST_UNLOCKED);
477 break;
478 default: /* Everything else */
479 printk(KERN_ERR "GFS2: wanted %u got %u\n", gl->gl_target, state);
480 GLOCK_BUG_ON(gl, 1);
481 }
482 spin_unlock(&gl->gl_spin);
483 return;
484 }
485
486 /* Fast path - we got what we asked for */
487 if (test_and_clear_bit(GLF_DEMOTE_IN_PROGRESS, &gl->gl_flags))
488 gfs2_demote_wake(gl);
489 if (state != LM_ST_UNLOCKED) {
490 if (glops->go_xmote_bh) {
491 spin_unlock(&gl->gl_spin);
492 rv = glops->go_xmote_bh(gl, gh);
493 spin_lock(&gl->gl_spin);
494 if (rv) {
495 do_error(gl, rv);
496 goto out;
497 }
498 }
499 rv = do_promote(gl);
500 if (rv == 2)
501 goto out_locked;
502 }
503 out:
504 clear_bit(GLF_LOCK, &gl->gl_flags);
505 out_locked:
506 spin_unlock(&gl->gl_spin);
507 }
508
509 /**
510 * do_xmote - Calls the DLM to change the state of a lock
511 * @gl: The lock state
512 * @gh: The holder (only for promotes)
513 * @target: The target lock state
514 *
515 */
516
517 static void do_xmote(struct gfs2_glock *gl, struct gfs2_holder *gh, unsigned int target)
518 __releases(&gl->gl_spin)
519 __acquires(&gl->gl_spin)
520 {
521 const struct gfs2_glock_operations *glops = gl->gl_ops;
522 struct gfs2_sbd *sdp = gl->gl_sbd;
523 unsigned int lck_flags = gh ? gh->gh_flags : 0;
524 int ret;
525
526 lck_flags &= (LM_FLAG_TRY | LM_FLAG_TRY_1CB | LM_FLAG_NOEXP |
527 LM_FLAG_PRIORITY);
528 GLOCK_BUG_ON(gl, gl->gl_state == target);
529 GLOCK_BUG_ON(gl, gl->gl_state == gl->gl_target);
530 if ((target == LM_ST_UNLOCKED || target == LM_ST_DEFERRED) &&
531 glops->go_inval) {
532 set_bit(GLF_INVALIDATE_IN_PROGRESS, &gl->gl_flags);
533 do_error(gl, 0); /* Fail queued try locks */
534 }
535 gl->gl_req = target;
536 spin_unlock(&gl->gl_spin);
537 if (glops->go_xmote_th)
538 glops->go_xmote_th(gl);
539 if (test_bit(GLF_INVALIDATE_IN_PROGRESS, &gl->gl_flags))
540 glops->go_inval(gl, target == LM_ST_DEFERRED ? 0 : DIO_METADATA);
541 clear_bit(GLF_INVALIDATE_IN_PROGRESS, &gl->gl_flags);
542
543 gfs2_glock_hold(gl);
544 if (sdp->sd_lockstruct.ls_ops->lm_lock) {
545 /* lock_dlm */
546 ret = sdp->sd_lockstruct.ls_ops->lm_lock(gl, target, lck_flags);
547 GLOCK_BUG_ON(gl, ret);
548 } else { /* lock_nolock */
549 finish_xmote(gl, target);
550 if (queue_delayed_work(glock_workqueue, &gl->gl_work, 0) == 0)
551 gfs2_glock_put(gl);
552 }
553
554 spin_lock(&gl->gl_spin);
555 }
556
557 /**
558 * find_first_holder - find the first "holder" gh
559 * @gl: the glock
560 */
561
562 static inline struct gfs2_holder *find_first_holder(const struct gfs2_glock *gl)
563 {
564 struct gfs2_holder *gh;
565
566 if (!list_empty(&gl->gl_holders)) {
567 gh = list_entry(gl->gl_holders.next, struct gfs2_holder, gh_list);
568 if (test_bit(HIF_HOLDER, &gh->gh_iflags))
569 return gh;
570 }
571 return NULL;
572 }
573
574 /**
575 * run_queue - do all outstanding tasks related to a glock
576 * @gl: The glock in question
577 * @nonblock: True if we must not block in run_queue
578 *
579 */
580
581 static void run_queue(struct gfs2_glock *gl, const int nonblock)
582 __releases(&gl->gl_spin)
583 __acquires(&gl->gl_spin)
584 {
585 struct gfs2_holder *gh = NULL;
586 int ret;
587
588 if (test_and_set_bit(GLF_LOCK, &gl->gl_flags))
589 return;
590
591 GLOCK_BUG_ON(gl, test_bit(GLF_DEMOTE_IN_PROGRESS, &gl->gl_flags));
592
593 if (test_bit(GLF_DEMOTE, &gl->gl_flags) &&
594 gl->gl_demote_state != gl->gl_state) {
595 if (find_first_holder(gl))
596 goto out_unlock;
597 if (nonblock)
598 goto out_sched;
599 set_bit(GLF_DEMOTE_IN_PROGRESS, &gl->gl_flags);
600 GLOCK_BUG_ON(gl, gl->gl_demote_state == LM_ST_EXCLUSIVE);
601 gl->gl_target = gl->gl_demote_state;
602 } else {
603 if (test_bit(GLF_DEMOTE, &gl->gl_flags))
604 gfs2_demote_wake(gl);
605 ret = do_promote(gl);
606 if (ret == 0)
607 goto out_unlock;
608 if (ret == 2)
609 goto out;
610 gh = find_first_waiter(gl);
611 gl->gl_target = gh->gh_state;
612 if (!(gh->gh_flags & (LM_FLAG_TRY | LM_FLAG_TRY_1CB)))
613 do_error(gl, 0); /* Fail queued try locks */
614 }
615 do_xmote(gl, gh, gl->gl_target);
616 out:
617 return;
618
619 out_sched:
620 clear_bit(GLF_LOCK, &gl->gl_flags);
621 smp_mb__after_clear_bit();
622 gfs2_glock_hold(gl);
623 if (queue_delayed_work(glock_workqueue, &gl->gl_work, 0) == 0)
624 gfs2_glock_put_nolock(gl);
625 return;
626
627 out_unlock:
628 clear_bit(GLF_LOCK, &gl->gl_flags);
629 smp_mb__after_clear_bit();
630 return;
631 }
632
633 static void delete_work_func(struct work_struct *work)
634 {
635 struct gfs2_glock *gl = container_of(work, struct gfs2_glock, gl_delete);
636 struct gfs2_sbd *sdp = gl->gl_sbd;
637 struct gfs2_inode *ip;
638 struct inode *inode;
639 u64 no_addr = gl->gl_name.ln_number;
640
641 ip = gl->gl_object;
642 /* Note: Unsafe to dereference ip as we don't hold right refs/locks */
643
644 if (ip)
645 inode = gfs2_ilookup(sdp->sd_vfs, no_addr, 1);
646 else
647 inode = gfs2_lookup_by_inum(sdp, no_addr, NULL, GFS2_BLKST_UNLINKED);
648 if (inode && !IS_ERR(inode)) {
649 d_prune_aliases(inode);
650 iput(inode);
651 }
652 gfs2_glock_put(gl);
653 }
654
655 static void glock_work_func(struct work_struct *work)
656 {
657 unsigned long delay = 0;
658 struct gfs2_glock *gl = container_of(work, struct gfs2_glock, gl_work.work);
659 int drop_ref = 0;
660
661 if (test_and_clear_bit(GLF_REPLY_PENDING, &gl->gl_flags)) {
662 finish_xmote(gl, gl->gl_reply);
663 drop_ref = 1;
664 }
665 spin_lock(&gl->gl_spin);
666 if (test_and_clear_bit(GLF_PENDING_DEMOTE, &gl->gl_flags) &&
667 gl->gl_state != LM_ST_UNLOCKED &&
668 gl->gl_demote_state != LM_ST_EXCLUSIVE) {
669 unsigned long holdtime, now = jiffies;
670 holdtime = gl->gl_tchange + gl->gl_ops->go_min_hold_time;
671 if (time_before(now, holdtime))
672 delay = holdtime - now;
673 set_bit(delay ? GLF_PENDING_DEMOTE : GLF_DEMOTE, &gl->gl_flags);
674 }
675 run_queue(gl, 0);
676 spin_unlock(&gl->gl_spin);
677 if (!delay ||
678 queue_delayed_work(glock_workqueue, &gl->gl_work, delay) == 0)
679 gfs2_glock_put(gl);
680 if (drop_ref)
681 gfs2_glock_put(gl);
682 }
683
684 /**
685 * gfs2_glock_get() - Get a glock, or create one if one doesn't exist
686 * @sdp: The GFS2 superblock
687 * @number: the lock number
688 * @glops: The glock_operations to use
689 * @create: If 0, don't create the glock if it doesn't exist
690 * @glp: the glock is returned here
691 *
692 * This does not lock a glock, just finds/creates structures for one.
693 *
694 * Returns: errno
695 */
696
697 int gfs2_glock_get(struct gfs2_sbd *sdp, u64 number,
698 const struct gfs2_glock_operations *glops, int create,
699 struct gfs2_glock **glp)
700 {
701 struct super_block *s = sdp->sd_vfs;
702 struct lm_lockname name = { .ln_number = number, .ln_type = glops->go_type };
703 struct gfs2_glock *gl, *tmp;
704 unsigned int hash = gl_hash(sdp, &name);
705 struct address_space *mapping;
706 struct kmem_cache *cachep;
707
708 rcu_read_lock();
709 gl = search_bucket(hash, sdp, &name);
710 rcu_read_unlock();
711
712 *glp = gl;
713 if (gl)
714 return 0;
715 if (!create)
716 return -ENOENT;
717
718 if (glops->go_flags & GLOF_ASPACE)
719 cachep = gfs2_glock_aspace_cachep;
720 else
721 cachep = gfs2_glock_cachep;
722 gl = kmem_cache_alloc(cachep, GFP_KERNEL);
723 if (!gl)
724 return -ENOMEM;
725
726 atomic_inc(&sdp->sd_glock_disposal);
727 gl->gl_flags = 0;
728 gl->gl_name = name;
729 atomic_set(&gl->gl_ref, 1);
730 gl->gl_state = LM_ST_UNLOCKED;
731 gl->gl_target = LM_ST_UNLOCKED;
732 gl->gl_demote_state = LM_ST_EXCLUSIVE;
733 gl->gl_hash = hash;
734 gl->gl_ops = glops;
735 snprintf(gl->gl_strname, GDLM_STRNAME_BYTES, "%8x%16llx", name.ln_type, (unsigned long long)number);
736 memset(&gl->gl_lksb, 0, sizeof(struct dlm_lksb));
737 gl->gl_lksb.sb_lvbptr = gl->gl_lvb;
738 gl->gl_tchange = jiffies;
739 gl->gl_object = NULL;
740 gl->gl_sbd = sdp;
741 INIT_DELAYED_WORK(&gl->gl_work, glock_work_func);
742 INIT_WORK(&gl->gl_delete, delete_work_func);
743
744 mapping = gfs2_glock2aspace(gl);
745 if (mapping) {
746 mapping->a_ops = &gfs2_meta_aops;
747 mapping->host = s->s_bdev->bd_inode;
748 mapping->flags = 0;
749 mapping_set_gfp_mask(mapping, GFP_NOFS);
750 mapping->assoc_mapping = NULL;
751 mapping->backing_dev_info = s->s_bdi;
752 mapping->writeback_index = 0;
753 }
754
755 spin_lock_bucket(hash);
756 tmp = search_bucket(hash, sdp, &name);
757 if (tmp) {
758 spin_unlock_bucket(hash);
759 kmem_cache_free(cachep, gl);
760 atomic_dec(&sdp->sd_glock_disposal);
761 gl = tmp;
762 } else {
763 hlist_bl_add_head_rcu(&gl->gl_list, &gl_hash_table[hash]);
764 spin_unlock_bucket(hash);
765 }
766
767 *glp = gl;
768
769 return 0;
770 }
771
772 /**
773 * gfs2_holder_init - initialize a struct gfs2_holder in the default way
774 * @gl: the glock
775 * @state: the state we're requesting
776 * @flags: the modifier flags
777 * @gh: the holder structure
778 *
779 */
780
781 void gfs2_holder_init(struct gfs2_glock *gl, unsigned int state, unsigned flags,
782 struct gfs2_holder *gh)
783 {
784 INIT_LIST_HEAD(&gh->gh_list);
785 gh->gh_gl = gl;
786 gh->gh_ip = (unsigned long)__builtin_return_address(0);
787 gh->gh_owner_pid = get_pid(task_pid(current));
788 gh->gh_state = state;
789 gh->gh_flags = flags;
790 gh->gh_error = 0;
791 gh->gh_iflags = 0;
792 gfs2_glock_hold(gl);
793 }
794
795 /**
796 * gfs2_holder_reinit - reinitialize a struct gfs2_holder so we can requeue it
797 * @state: the state we're requesting
798 * @flags: the modifier flags
799 * @gh: the holder structure
800 *
801 * Don't mess with the glock.
802 *
803 */
804
805 void gfs2_holder_reinit(unsigned int state, unsigned flags, struct gfs2_holder *gh)
806 {
807 gh->gh_state = state;
808 gh->gh_flags = flags;
809 gh->gh_iflags = 0;
810 gh->gh_ip = (unsigned long)__builtin_return_address(0);
811 if (gh->gh_owner_pid)
812 put_pid(gh->gh_owner_pid);
813 gh->gh_owner_pid = get_pid(task_pid(current));
814 }
815
816 /**
817 * gfs2_holder_uninit - uninitialize a holder structure (drop glock reference)
818 * @gh: the holder structure
819 *
820 */
821
822 void gfs2_holder_uninit(struct gfs2_holder *gh)
823 {
824 put_pid(gh->gh_owner_pid);
825 gfs2_glock_put(gh->gh_gl);
826 gh->gh_gl = NULL;
827 gh->gh_ip = 0;
828 }
829
830 /**
831 * gfs2_glock_holder_wait
832 * @word: unused
833 *
834 * This function and gfs2_glock_demote_wait both show up in the WCHAN
835 * field. Thus I've separated these otherwise identical functions in
836 * order to be more informative to the user.
837 */
838
839 static int gfs2_glock_holder_wait(void *word)
840 {
841 schedule();
842 return 0;
843 }
844
845 static int gfs2_glock_demote_wait(void *word)
846 {
847 schedule();
848 return 0;
849 }
850
851 static void wait_on_holder(struct gfs2_holder *gh)
852 {
853 might_sleep();
854 wait_on_bit(&gh->gh_iflags, HIF_WAIT, gfs2_glock_holder_wait, TASK_UNINTERRUPTIBLE);
855 }
856
857 static void wait_on_demote(struct gfs2_glock *gl)
858 {
859 might_sleep();
860 wait_on_bit(&gl->gl_flags, GLF_DEMOTE, gfs2_glock_demote_wait, TASK_UNINTERRUPTIBLE);
861 }
862
863 /**
864 * handle_callback - process a demote request
865 * @gl: the glock
866 * @state: the state the caller wants us to change to
867 *
868 * There are only two requests that we are going to see in actual
869 * practise: LM_ST_SHARED and LM_ST_UNLOCKED
870 */
871
872 static void handle_callback(struct gfs2_glock *gl, unsigned int state,
873 unsigned long delay)
874 {
875 int bit = delay ? GLF_PENDING_DEMOTE : GLF_DEMOTE;
876
877 set_bit(bit, &gl->gl_flags);
878 if (gl->gl_demote_state == LM_ST_EXCLUSIVE) {
879 gl->gl_demote_state = state;
880 gl->gl_demote_time = jiffies;
881 } else if (gl->gl_demote_state != LM_ST_UNLOCKED &&
882 gl->gl_demote_state != state) {
883 gl->gl_demote_state = LM_ST_UNLOCKED;
884 }
885 if (gl->gl_ops->go_callback)
886 gl->gl_ops->go_callback(gl);
887 trace_gfs2_demote_rq(gl);
888 }
889
890 /**
891 * gfs2_glock_wait - wait on a glock acquisition
892 * @gh: the glock holder
893 *
894 * Returns: 0 on success
895 */
896
897 int gfs2_glock_wait(struct gfs2_holder *gh)
898 {
899 wait_on_holder(gh);
900 return gh->gh_error;
901 }
902
903 void gfs2_print_dbg(struct seq_file *seq, const char *fmt, ...)
904 {
905 struct va_format vaf;
906 va_list args;
907
908 va_start(args, fmt);
909
910 if (seq) {
911 struct gfs2_glock_iter *gi = seq->private;
912 vsprintf(gi->string, fmt, args);
913 seq_printf(seq, gi->string);
914 } else {
915 vaf.fmt = fmt;
916 vaf.va = &args;
917
918 printk(KERN_ERR " %pV", &vaf);
919 }
920
921 va_end(args);
922 }
923
924 /**
925 * add_to_queue - Add a holder to the wait queue (but look for recursion)
926 * @gh: the holder structure to add
927 *
928 * Eventually we should move the recursive locking trap to a
929 * debugging option or something like that. This is the fast
930 * path and needs to have the minimum number of distractions.
931 *
932 */
933
934 static inline void add_to_queue(struct gfs2_holder *gh)
935 __releases(&gl->gl_spin)
936 __acquires(&gl->gl_spin)
937 {
938 struct gfs2_glock *gl = gh->gh_gl;
939 struct gfs2_sbd *sdp = gl->gl_sbd;
940 struct list_head *insert_pt = NULL;
941 struct gfs2_holder *gh2;
942 int try_lock = 0;
943
944 BUG_ON(gh->gh_owner_pid == NULL);
945 if (test_and_set_bit(HIF_WAIT, &gh->gh_iflags))
946 BUG();
947
948 if (gh->gh_flags & (LM_FLAG_TRY | LM_FLAG_TRY_1CB)) {
949 if (test_bit(GLF_LOCK, &gl->gl_flags))
950 try_lock = 1;
951 if (test_bit(GLF_INVALIDATE_IN_PROGRESS, &gl->gl_flags))
952 goto fail;
953 }
954
955 list_for_each_entry(gh2, &gl->gl_holders, gh_list) {
956 if (unlikely(gh2->gh_owner_pid == gh->gh_owner_pid &&
957 (gh->gh_gl->gl_ops->go_type != LM_TYPE_FLOCK)))
958 goto trap_recursive;
959 if (try_lock &&
960 !(gh2->gh_flags & (LM_FLAG_TRY | LM_FLAG_TRY_1CB)) &&
961 !may_grant(gl, gh)) {
962 fail:
963 gh->gh_error = GLR_TRYFAILED;
964 gfs2_holder_wake(gh);
965 return;
966 }
967 if (test_bit(HIF_HOLDER, &gh2->gh_iflags))
968 continue;
969 if (unlikely((gh->gh_flags & LM_FLAG_PRIORITY) && !insert_pt))
970 insert_pt = &gh2->gh_list;
971 }
972 set_bit(GLF_QUEUED, &gl->gl_flags);
973 trace_gfs2_glock_queue(gh, 1);
974 if (likely(insert_pt == NULL)) {
975 list_add_tail(&gh->gh_list, &gl->gl_holders);
976 if (unlikely(gh->gh_flags & LM_FLAG_PRIORITY))
977 goto do_cancel;
978 return;
979 }
980 list_add_tail(&gh->gh_list, insert_pt);
981 do_cancel:
982 gh = list_entry(gl->gl_holders.next, struct gfs2_holder, gh_list);
983 if (!(gh->gh_flags & LM_FLAG_PRIORITY)) {
984 spin_unlock(&gl->gl_spin);
985 if (sdp->sd_lockstruct.ls_ops->lm_cancel)
986 sdp->sd_lockstruct.ls_ops->lm_cancel(gl);
987 spin_lock(&gl->gl_spin);
988 }
989 return;
990
991 trap_recursive:
992 print_symbol(KERN_ERR "original: %s\n", gh2->gh_ip);
993 printk(KERN_ERR "pid: %d\n", pid_nr(gh2->gh_owner_pid));
994 printk(KERN_ERR "lock type: %d req lock state : %d\n",
995 gh2->gh_gl->gl_name.ln_type, gh2->gh_state);
996 print_symbol(KERN_ERR "new: %s\n", gh->gh_ip);
997 printk(KERN_ERR "pid: %d\n", pid_nr(gh->gh_owner_pid));
998 printk(KERN_ERR "lock type: %d req lock state : %d\n",
999 gh->gh_gl->gl_name.ln_type, gh->gh_state);
1000 __dump_glock(NULL, gl);
1001 BUG();
1002 }
1003
1004 /**
1005 * gfs2_glock_nq - enqueue a struct gfs2_holder onto a glock (acquire a glock)
1006 * @gh: the holder structure
1007 *
1008 * if (gh->gh_flags & GL_ASYNC), this never returns an error
1009 *
1010 * Returns: 0, GLR_TRYFAILED, or errno on failure
1011 */
1012
1013 int gfs2_glock_nq(struct gfs2_holder *gh)
1014 {
1015 struct gfs2_glock *gl = gh->gh_gl;
1016 struct gfs2_sbd *sdp = gl->gl_sbd;
1017 int error = 0;
1018
1019 if (unlikely(test_bit(SDF_SHUTDOWN, &sdp->sd_flags)))
1020 return -EIO;
1021
1022 if (test_bit(GLF_LRU, &gl->gl_flags))
1023 gfs2_glock_remove_from_lru(gl);
1024
1025 spin_lock(&gl->gl_spin);
1026 add_to_queue(gh);
1027 if ((LM_FLAG_NOEXP & gh->gh_flags) &&
1028 test_and_clear_bit(GLF_FROZEN, &gl->gl_flags))
1029 set_bit(GLF_REPLY_PENDING, &gl->gl_flags);
1030 run_queue(gl, 1);
1031 spin_unlock(&gl->gl_spin);
1032
1033 if (!(gh->gh_flags & GL_ASYNC))
1034 error = gfs2_glock_wait(gh);
1035
1036 return error;
1037 }
1038
1039 /**
1040 * gfs2_glock_poll - poll to see if an async request has been completed
1041 * @gh: the holder
1042 *
1043 * Returns: 1 if the request is ready to be gfs2_glock_wait()ed on
1044 */
1045
1046 int gfs2_glock_poll(struct gfs2_holder *gh)
1047 {
1048 return test_bit(HIF_WAIT, &gh->gh_iflags) ? 0 : 1;
1049 }
1050
1051 /**
1052 * gfs2_glock_dq - dequeue a struct gfs2_holder from a glock (release a glock)
1053 * @gh: the glock holder
1054 *
1055 */
1056
1057 void gfs2_glock_dq(struct gfs2_holder *gh)
1058 {
1059 struct gfs2_glock *gl = gh->gh_gl;
1060 const struct gfs2_glock_operations *glops = gl->gl_ops;
1061 unsigned delay = 0;
1062 int fast_path = 0;
1063
1064 spin_lock(&gl->gl_spin);
1065 if (gh->gh_flags & GL_NOCACHE)
1066 handle_callback(gl, LM_ST_UNLOCKED, 0);
1067
1068 list_del_init(&gh->gh_list);
1069 if (find_first_holder(gl) == NULL) {
1070 if (glops->go_unlock) {
1071 GLOCK_BUG_ON(gl, test_and_set_bit(GLF_LOCK, &gl->gl_flags));
1072 spin_unlock(&gl->gl_spin);
1073 glops->go_unlock(gh);
1074 spin_lock(&gl->gl_spin);
1075 clear_bit(GLF_LOCK, &gl->gl_flags);
1076 }
1077 if (list_empty(&gl->gl_holders) &&
1078 !test_bit(GLF_PENDING_DEMOTE, &gl->gl_flags) &&
1079 !test_bit(GLF_DEMOTE, &gl->gl_flags))
1080 fast_path = 1;
1081 }
1082 if (!test_bit(GLF_LFLUSH, &gl->gl_flags))
1083 __gfs2_glock_schedule_for_reclaim(gl);
1084 trace_gfs2_glock_queue(gh, 0);
1085 spin_unlock(&gl->gl_spin);
1086 if (likely(fast_path))
1087 return;
1088
1089 gfs2_glock_hold(gl);
1090 if (test_bit(GLF_PENDING_DEMOTE, &gl->gl_flags) &&
1091 !test_bit(GLF_DEMOTE, &gl->gl_flags))
1092 delay = gl->gl_ops->go_min_hold_time;
1093 if (queue_delayed_work(glock_workqueue, &gl->gl_work, delay) == 0)
1094 gfs2_glock_put(gl);
1095 }
1096
1097 void gfs2_glock_dq_wait(struct gfs2_holder *gh)
1098 {
1099 struct gfs2_glock *gl = gh->gh_gl;
1100 gfs2_glock_dq(gh);
1101 wait_on_demote(gl);
1102 }
1103
1104 /**
1105 * gfs2_glock_dq_uninit - dequeue a holder from a glock and initialize it
1106 * @gh: the holder structure
1107 *
1108 */
1109
1110 void gfs2_glock_dq_uninit(struct gfs2_holder *gh)
1111 {
1112 gfs2_glock_dq(gh);
1113 gfs2_holder_uninit(gh);
1114 }
1115
1116 /**
1117 * gfs2_glock_nq_num - acquire a glock based on lock number
1118 * @sdp: the filesystem
1119 * @number: the lock number
1120 * @glops: the glock operations for the type of glock
1121 * @state: the state to acquire the glock in
1122 * @flags: modifier flags for the acquisition
1123 * @gh: the struct gfs2_holder
1124 *
1125 * Returns: errno
1126 */
1127
1128 int gfs2_glock_nq_num(struct gfs2_sbd *sdp, u64 number,
1129 const struct gfs2_glock_operations *glops,
1130 unsigned int state, int flags, struct gfs2_holder *gh)
1131 {
1132 struct gfs2_glock *gl;
1133 int error;
1134
1135 error = gfs2_glock_get(sdp, number, glops, CREATE, &gl);
1136 if (!error) {
1137 error = gfs2_glock_nq_init(gl, state, flags, gh);
1138 gfs2_glock_put(gl);
1139 }
1140
1141 return error;
1142 }
1143
1144 /**
1145 * glock_compare - Compare two struct gfs2_glock structures for sorting
1146 * @arg_a: the first structure
1147 * @arg_b: the second structure
1148 *
1149 */
1150
1151 static int glock_compare(const void *arg_a, const void *arg_b)
1152 {
1153 const struct gfs2_holder *gh_a = *(const struct gfs2_holder **)arg_a;
1154 const struct gfs2_holder *gh_b = *(const struct gfs2_holder **)arg_b;
1155 const struct lm_lockname *a = &gh_a->gh_gl->gl_name;
1156 const struct lm_lockname *b = &gh_b->gh_gl->gl_name;
1157
1158 if (a->ln_number > b->ln_number)
1159 return 1;
1160 if (a->ln_number < b->ln_number)
1161 return -1;
1162 BUG_ON(gh_a->gh_gl->gl_ops->go_type == gh_b->gh_gl->gl_ops->go_type);
1163 return 0;
1164 }
1165
1166 /**
1167 * nq_m_sync - synchonously acquire more than one glock in deadlock free order
1168 * @num_gh: the number of structures
1169 * @ghs: an array of struct gfs2_holder structures
1170 *
1171 * Returns: 0 on success (all glocks acquired),
1172 * errno on failure (no glocks acquired)
1173 */
1174
1175 static int nq_m_sync(unsigned int num_gh, struct gfs2_holder *ghs,
1176 struct gfs2_holder **p)
1177 {
1178 unsigned int x;
1179 int error = 0;
1180
1181 for (x = 0; x < num_gh; x++)
1182 p[x] = &ghs[x];
1183
1184 sort(p, num_gh, sizeof(struct gfs2_holder *), glock_compare, NULL);
1185
1186 for (x = 0; x < num_gh; x++) {
1187 p[x]->gh_flags &= ~(LM_FLAG_TRY | GL_ASYNC);
1188
1189 error = gfs2_glock_nq(p[x]);
1190 if (error) {
1191 while (x--)
1192 gfs2_glock_dq(p[x]);
1193 break;
1194 }
1195 }
1196
1197 return error;
1198 }
1199
1200 /**
1201 * gfs2_glock_nq_m - acquire multiple glocks
1202 * @num_gh: the number of structures
1203 * @ghs: an array of struct gfs2_holder structures
1204 *
1205 *
1206 * Returns: 0 on success (all glocks acquired),
1207 * errno on failure (no glocks acquired)
1208 */
1209
1210 int gfs2_glock_nq_m(unsigned int num_gh, struct gfs2_holder *ghs)
1211 {
1212 struct gfs2_holder *tmp[4];
1213 struct gfs2_holder **pph = tmp;
1214 int error = 0;
1215
1216 switch(num_gh) {
1217 case 0:
1218 return 0;
1219 case 1:
1220 ghs->gh_flags &= ~(LM_FLAG_TRY | GL_ASYNC);
1221 return gfs2_glock_nq(ghs);
1222 default:
1223 if (num_gh <= 4)
1224 break;
1225 pph = kmalloc(num_gh * sizeof(struct gfs2_holder *), GFP_NOFS);
1226 if (!pph)
1227 return -ENOMEM;
1228 }
1229
1230 error = nq_m_sync(num_gh, ghs, pph);
1231
1232 if (pph != tmp)
1233 kfree(pph);
1234
1235 return error;
1236 }
1237
1238 /**
1239 * gfs2_glock_dq_m - release multiple glocks
1240 * @num_gh: the number of structures
1241 * @ghs: an array of struct gfs2_holder structures
1242 *
1243 */
1244
1245 void gfs2_glock_dq_m(unsigned int num_gh, struct gfs2_holder *ghs)
1246 {
1247 while (num_gh--)
1248 gfs2_glock_dq(&ghs[num_gh]);
1249 }
1250
1251 /**
1252 * gfs2_glock_dq_uninit_m - release multiple glocks
1253 * @num_gh: the number of structures
1254 * @ghs: an array of struct gfs2_holder structures
1255 *
1256 */
1257
1258 void gfs2_glock_dq_uninit_m(unsigned int num_gh, struct gfs2_holder *ghs)
1259 {
1260 while (num_gh--)
1261 gfs2_glock_dq_uninit(&ghs[num_gh]);
1262 }
1263
1264 void gfs2_glock_cb(struct gfs2_glock *gl, unsigned int state)
1265 {
1266 unsigned long delay = 0;
1267 unsigned long holdtime;
1268 unsigned long now = jiffies;
1269
1270 gfs2_glock_hold(gl);
1271 holdtime = gl->gl_tchange + gl->gl_ops->go_min_hold_time;
1272 if (test_bit(GLF_QUEUED, &gl->gl_flags)) {
1273 if (time_before(now, holdtime))
1274 delay = holdtime - now;
1275 if (test_bit(GLF_REPLY_PENDING, &gl->gl_flags))
1276 delay = gl->gl_ops->go_min_hold_time;
1277 }
1278
1279 spin_lock(&gl->gl_spin);
1280 handle_callback(gl, state, delay);
1281 spin_unlock(&gl->gl_spin);
1282 if (queue_delayed_work(glock_workqueue, &gl->gl_work, delay) == 0)
1283 gfs2_glock_put(gl);
1284 }
1285
1286 /**
1287 * gfs2_should_freeze - Figure out if glock should be frozen
1288 * @gl: The glock in question
1289 *
1290 * Glocks are not frozen if (a) the result of the dlm operation is
1291 * an error, (b) the locking operation was an unlock operation or
1292 * (c) if there is a "noexp" flagged request anywhere in the queue
1293 *
1294 * Returns: 1 if freezing should occur, 0 otherwise
1295 */
1296
1297 static int gfs2_should_freeze(const struct gfs2_glock *gl)
1298 {
1299 const struct gfs2_holder *gh;
1300
1301 if (gl->gl_reply & ~LM_OUT_ST_MASK)
1302 return 0;
1303 if (gl->gl_target == LM_ST_UNLOCKED)
1304 return 0;
1305
1306 list_for_each_entry(gh, &gl->gl_holders, gh_list) {
1307 if (test_bit(HIF_HOLDER, &gh->gh_iflags))
1308 continue;
1309 if (LM_FLAG_NOEXP & gh->gh_flags)
1310 return 0;
1311 }
1312
1313 return 1;
1314 }
1315
1316 /**
1317 * gfs2_glock_complete - Callback used by locking
1318 * @gl: Pointer to the glock
1319 * @ret: The return value from the dlm
1320 *
1321 * The gl_reply field is under the gl_spin lock so that it is ok
1322 * to use a bitfield shared with other glock state fields.
1323 */
1324
1325 void gfs2_glock_complete(struct gfs2_glock *gl, int ret)
1326 {
1327 struct lm_lockstruct *ls = &gl->gl_sbd->sd_lockstruct;
1328
1329 spin_lock(&gl->gl_spin);
1330 gl->gl_reply = ret;
1331
1332 if (unlikely(test_bit(DFL_BLOCK_LOCKS, &ls->ls_flags))) {
1333 if (gfs2_should_freeze(gl)) {
1334 set_bit(GLF_FROZEN, &gl->gl_flags);
1335 spin_unlock(&gl->gl_spin);
1336 return;
1337 }
1338 }
1339
1340 spin_unlock(&gl->gl_spin);
1341 set_bit(GLF_REPLY_PENDING, &gl->gl_flags);
1342 smp_wmb();
1343 gfs2_glock_hold(gl);
1344 if (queue_delayed_work(glock_workqueue, &gl->gl_work, 0) == 0)
1345 gfs2_glock_put(gl);
1346 }
1347
1348
1349 static int gfs2_shrink_glock_memory(struct shrinker *shrink, int nr, gfp_t gfp_mask)
1350 {
1351 struct gfs2_glock *gl;
1352 int may_demote;
1353 int nr_skipped = 0;
1354 LIST_HEAD(skipped);
1355
1356 if (nr == 0)
1357 goto out;
1358
1359 if (!(gfp_mask & __GFP_FS))
1360 return -1;
1361
1362 spin_lock(&lru_lock);
1363 while(nr && !list_empty(&lru_list)) {
1364 gl = list_entry(lru_list.next, struct gfs2_glock, gl_lru);
1365 list_del_init(&gl->gl_lru);
1366 clear_bit(GLF_LRU, &gl->gl_flags);
1367 atomic_dec(&lru_count);
1368
1369 /* Test for being demotable */
1370 if (!test_and_set_bit(GLF_LOCK, &gl->gl_flags)) {
1371 gfs2_glock_hold(gl);
1372 spin_unlock(&lru_lock);
1373 spin_lock(&gl->gl_spin);
1374 may_demote = demote_ok(gl);
1375 if (may_demote) {
1376 handle_callback(gl, LM_ST_UNLOCKED, 0);
1377 nr--;
1378 }
1379 clear_bit(GLF_LOCK, &gl->gl_flags);
1380 smp_mb__after_clear_bit();
1381 if (queue_delayed_work(glock_workqueue, &gl->gl_work, 0) == 0)
1382 gfs2_glock_put_nolock(gl);
1383 spin_unlock(&gl->gl_spin);
1384 spin_lock(&lru_lock);
1385 continue;
1386 }
1387 nr_skipped++;
1388 list_add(&gl->gl_lru, &skipped);
1389 set_bit(GLF_LRU, &gl->gl_flags);
1390 }
1391 list_splice(&skipped, &lru_list);
1392 atomic_add(nr_skipped, &lru_count);
1393 spin_unlock(&lru_lock);
1394 out:
1395 return (atomic_read(&lru_count) / 100) * sysctl_vfs_cache_pressure;
1396 }
1397
1398 static struct shrinker glock_shrinker = {
1399 .shrink = gfs2_shrink_glock_memory,
1400 .seeks = DEFAULT_SEEKS,
1401 };
1402
1403 /**
1404 * examine_bucket - Call a function for glock in a hash bucket
1405 * @examiner: the function
1406 * @sdp: the filesystem
1407 * @bucket: the bucket
1408 *
1409 */
1410
1411 static void examine_bucket(glock_examiner examiner, const struct gfs2_sbd *sdp,
1412 unsigned int hash)
1413 {
1414 struct gfs2_glock *gl;
1415 struct hlist_bl_head *head = &gl_hash_table[hash];
1416 struct hlist_bl_node *pos;
1417
1418 rcu_read_lock();
1419 hlist_bl_for_each_entry_rcu(gl, pos, head, gl_list) {
1420 if ((gl->gl_sbd == sdp) && atomic_read(&gl->gl_ref))
1421 examiner(gl);
1422 }
1423 rcu_read_unlock();
1424 cond_resched();
1425 }
1426
1427 static void glock_hash_walk(glock_examiner examiner, const struct gfs2_sbd *sdp)
1428 {
1429 unsigned x;
1430
1431 for (x = 0; x < GFS2_GL_HASH_SIZE; x++)
1432 examine_bucket(examiner, sdp, x);
1433 }
1434
1435
1436 /**
1437 * thaw_glock - thaw out a glock which has an unprocessed reply waiting
1438 * @gl: The glock to thaw
1439 *
1440 * N.B. When we freeze a glock, we leave a ref to the glock outstanding,
1441 * so this has to result in the ref count being dropped by one.
1442 */
1443
1444 static void thaw_glock(struct gfs2_glock *gl)
1445 {
1446 if (!test_and_clear_bit(GLF_FROZEN, &gl->gl_flags))
1447 return;
1448 set_bit(GLF_REPLY_PENDING, &gl->gl_flags);
1449 gfs2_glock_hold(gl);
1450 if (queue_delayed_work(glock_workqueue, &gl->gl_work, 0) == 0)
1451 gfs2_glock_put(gl);
1452 }
1453
1454 /**
1455 * clear_glock - look at a glock and see if we can free it from glock cache
1456 * @gl: the glock to look at
1457 *
1458 */
1459
1460 static void clear_glock(struct gfs2_glock *gl)
1461 {
1462 gfs2_glock_remove_from_lru(gl);
1463
1464 spin_lock(&gl->gl_spin);
1465 if (gl->gl_state != LM_ST_UNLOCKED)
1466 handle_callback(gl, LM_ST_UNLOCKED, 0);
1467 spin_unlock(&gl->gl_spin);
1468 gfs2_glock_hold(gl);
1469 if (queue_delayed_work(glock_workqueue, &gl->gl_work, 0) == 0)
1470 gfs2_glock_put(gl);
1471 }
1472
1473 /**
1474 * gfs2_glock_thaw - Thaw any frozen glocks
1475 * @sdp: The super block
1476 *
1477 */
1478
1479 void gfs2_glock_thaw(struct gfs2_sbd *sdp)
1480 {
1481 glock_hash_walk(thaw_glock, sdp);
1482 }
1483
1484 static int dump_glock(struct seq_file *seq, struct gfs2_glock *gl)
1485 {
1486 int ret;
1487 spin_lock(&gl->gl_spin);
1488 ret = __dump_glock(seq, gl);
1489 spin_unlock(&gl->gl_spin);
1490 return ret;
1491 }
1492
1493 static void dump_glock_func(struct gfs2_glock *gl)
1494 {
1495 dump_glock(NULL, gl);
1496 }
1497
1498 /**
1499 * gfs2_gl_hash_clear - Empty out the glock hash table
1500 * @sdp: the filesystem
1501 * @wait: wait until it's all gone
1502 *
1503 * Called when unmounting the filesystem.
1504 */
1505
1506 void gfs2_gl_hash_clear(struct gfs2_sbd *sdp)
1507 {
1508 glock_hash_walk(clear_glock, sdp);
1509 flush_workqueue(glock_workqueue);
1510 wait_event(sdp->sd_glock_wait, atomic_read(&sdp->sd_glock_disposal) == 0);
1511 glock_hash_walk(dump_glock_func, sdp);
1512 }
1513
1514 void gfs2_glock_finish_truncate(struct gfs2_inode *ip)
1515 {
1516 struct gfs2_glock *gl = ip->i_gl;
1517 int ret;
1518
1519 ret = gfs2_truncatei_resume(ip);
1520 gfs2_assert_withdraw(gl->gl_sbd, ret == 0);
1521
1522 spin_lock(&gl->gl_spin);
1523 clear_bit(GLF_LOCK, &gl->gl_flags);
1524 run_queue(gl, 1);
1525 spin_unlock(&gl->gl_spin);
1526 }
1527
1528 static const char *state2str(unsigned state)
1529 {
1530 switch(state) {
1531 case LM_ST_UNLOCKED:
1532 return "UN";
1533 case LM_ST_SHARED:
1534 return "SH";
1535 case LM_ST_DEFERRED:
1536 return "DF";
1537 case LM_ST_EXCLUSIVE:
1538 return "EX";
1539 }
1540 return "??";
1541 }
1542
1543 static const char *hflags2str(char *buf, unsigned flags, unsigned long iflags)
1544 {
1545 char *p = buf;
1546 if (flags & LM_FLAG_TRY)
1547 *p++ = 't';
1548 if (flags & LM_FLAG_TRY_1CB)
1549 *p++ = 'T';
1550 if (flags & LM_FLAG_NOEXP)
1551 *p++ = 'e';
1552 if (flags & LM_FLAG_ANY)
1553 *p++ = 'A';
1554 if (flags & LM_FLAG_PRIORITY)
1555 *p++ = 'p';
1556 if (flags & GL_ASYNC)
1557 *p++ = 'a';
1558 if (flags & GL_EXACT)
1559 *p++ = 'E';
1560 if (flags & GL_NOCACHE)
1561 *p++ = 'c';
1562 if (test_bit(HIF_HOLDER, &iflags))
1563 *p++ = 'H';
1564 if (test_bit(HIF_WAIT, &iflags))
1565 *p++ = 'W';
1566 if (test_bit(HIF_FIRST, &iflags))
1567 *p++ = 'F';
1568 *p = 0;
1569 return buf;
1570 }
1571
1572 /**
1573 * dump_holder - print information about a glock holder
1574 * @seq: the seq_file struct
1575 * @gh: the glock holder
1576 *
1577 * Returns: 0 on success, -ENOBUFS when we run out of space
1578 */
1579
1580 static int dump_holder(struct seq_file *seq, const struct gfs2_holder *gh)
1581 {
1582 struct task_struct *gh_owner = NULL;
1583 char flags_buf[32];
1584
1585 if (gh->gh_owner_pid)
1586 gh_owner = pid_task(gh->gh_owner_pid, PIDTYPE_PID);
1587 gfs2_print_dbg(seq, " H: s:%s f:%s e:%d p:%ld [%s] %pS\n",
1588 state2str(gh->gh_state),
1589 hflags2str(flags_buf, gh->gh_flags, gh->gh_iflags),
1590 gh->gh_error,
1591 gh->gh_owner_pid ? (long)pid_nr(gh->gh_owner_pid) : -1,
1592 gh_owner ? gh_owner->comm : "(ended)",
1593 (void *)gh->gh_ip);
1594 return 0;
1595 }
1596
1597 static const char *gflags2str(char *buf, const struct gfs2_glock *gl)
1598 {
1599 const unsigned long *gflags = &gl->gl_flags;
1600 char *p = buf;
1601
1602 if (test_bit(GLF_LOCK, gflags))
1603 *p++ = 'l';
1604 if (test_bit(GLF_DEMOTE, gflags))
1605 *p++ = 'D';
1606 if (test_bit(GLF_PENDING_DEMOTE, gflags))
1607 *p++ = 'd';
1608 if (test_bit(GLF_DEMOTE_IN_PROGRESS, gflags))
1609 *p++ = 'p';
1610 if (test_bit(GLF_DIRTY, gflags))
1611 *p++ = 'y';
1612 if (test_bit(GLF_LFLUSH, gflags))
1613 *p++ = 'f';
1614 if (test_bit(GLF_INVALIDATE_IN_PROGRESS, gflags))
1615 *p++ = 'i';
1616 if (test_bit(GLF_REPLY_PENDING, gflags))
1617 *p++ = 'r';
1618 if (test_bit(GLF_INITIAL, gflags))
1619 *p++ = 'I';
1620 if (test_bit(GLF_FROZEN, gflags))
1621 *p++ = 'F';
1622 if (test_bit(GLF_QUEUED, gflags))
1623 *p++ = 'q';
1624 if (test_bit(GLF_LRU, gflags))
1625 *p++ = 'L';
1626 if (gl->gl_object)
1627 *p++ = 'o';
1628 *p = 0;
1629 return buf;
1630 }
1631
1632 /**
1633 * __dump_glock - print information about a glock
1634 * @seq: The seq_file struct
1635 * @gl: the glock
1636 *
1637 * The file format is as follows:
1638 * One line per object, capital letters are used to indicate objects
1639 * G = glock, I = Inode, R = rgrp, H = holder. Glocks are not indented,
1640 * other objects are indented by a single space and follow the glock to
1641 * which they are related. Fields are indicated by lower case letters
1642 * followed by a colon and the field value, except for strings which are in
1643 * [] so that its possible to see if they are composed of spaces for
1644 * example. The field's are n = number (id of the object), f = flags,
1645 * t = type, s = state, r = refcount, e = error, p = pid.
1646 *
1647 * Returns: 0 on success, -ENOBUFS when we run out of space
1648 */
1649
1650 static int __dump_glock(struct seq_file *seq, const struct gfs2_glock *gl)
1651 {
1652 const struct gfs2_glock_operations *glops = gl->gl_ops;
1653 unsigned long long dtime;
1654 const struct gfs2_holder *gh;
1655 char gflags_buf[32];
1656 int error = 0;
1657
1658 dtime = jiffies - gl->gl_demote_time;
1659 dtime *= 1000000/HZ; /* demote time in uSec */
1660 if (!test_bit(GLF_DEMOTE, &gl->gl_flags))
1661 dtime = 0;
1662 gfs2_print_dbg(seq, "G: s:%s n:%u/%llx f:%s t:%s d:%s/%llu a:%d v:%d r:%d\n",
1663 state2str(gl->gl_state),
1664 gl->gl_name.ln_type,
1665 (unsigned long long)gl->gl_name.ln_number,
1666 gflags2str(gflags_buf, gl),
1667 state2str(gl->gl_target),
1668 state2str(gl->gl_demote_state), dtime,
1669 atomic_read(&gl->gl_ail_count),
1670 atomic_read(&gl->gl_revokes),
1671 atomic_read(&gl->gl_ref));
1672
1673 list_for_each_entry(gh, &gl->gl_holders, gh_list) {
1674 error = dump_holder(seq, gh);
1675 if (error)
1676 goto out;
1677 }
1678 if (gl->gl_state != LM_ST_UNLOCKED && glops->go_dump)
1679 error = glops->go_dump(seq, gl);
1680 out:
1681 return error;
1682 }
1683
1684
1685
1686
1687 int __init gfs2_glock_init(void)
1688 {
1689 unsigned i;
1690 for(i = 0; i < GFS2_GL_HASH_SIZE; i++) {
1691 INIT_HLIST_BL_HEAD(&gl_hash_table[i]);
1692 }
1693
1694 glock_workqueue = alloc_workqueue("glock_workqueue", WQ_MEM_RECLAIM |
1695 WQ_HIGHPRI | WQ_FREEZABLE, 0);
1696 if (IS_ERR(glock_workqueue))
1697 return PTR_ERR(glock_workqueue);
1698 gfs2_delete_workqueue = alloc_workqueue("delete_workqueue",
1699 WQ_MEM_RECLAIM | WQ_FREEZABLE,
1700 0);
1701 if (IS_ERR(gfs2_delete_workqueue)) {
1702 destroy_workqueue(glock_workqueue);
1703 return PTR_ERR(gfs2_delete_workqueue);
1704 }
1705
1706 register_shrinker(&glock_shrinker);
1707
1708 return 0;
1709 }
1710
1711 void gfs2_glock_exit(void)
1712 {
1713 unregister_shrinker(&glock_shrinker);
1714 destroy_workqueue(glock_workqueue);
1715 destroy_workqueue(gfs2_delete_workqueue);
1716 }
1717
1718 static inline struct gfs2_glock *glock_hash_chain(unsigned hash)
1719 {
1720 return hlist_bl_entry(hlist_bl_first_rcu(&gl_hash_table[hash]),
1721 struct gfs2_glock, gl_list);
1722 }
1723
1724 static inline struct gfs2_glock *glock_hash_next(struct gfs2_glock *gl)
1725 {
1726 return hlist_bl_entry(rcu_dereference(gl->gl_list.next),
1727 struct gfs2_glock, gl_list);
1728 }
1729
1730 static int gfs2_glock_iter_next(struct gfs2_glock_iter *gi)
1731 {
1732 struct gfs2_glock *gl;
1733
1734 do {
1735 gl = gi->gl;
1736 if (gl) {
1737 gi->gl = glock_hash_next(gl);
1738 } else {
1739 gi->gl = glock_hash_chain(gi->hash);
1740 }
1741 while (gi->gl == NULL) {
1742 gi->hash++;
1743 if (gi->hash >= GFS2_GL_HASH_SIZE) {
1744 rcu_read_unlock();
1745 return 1;
1746 }
1747 gi->gl = glock_hash_chain(gi->hash);
1748 }
1749 /* Skip entries for other sb and dead entries */
1750 } while (gi->sdp != gi->gl->gl_sbd || atomic_read(&gi->gl->gl_ref) == 0);
1751
1752 return 0;
1753 }
1754
1755 static void *gfs2_glock_seq_start(struct seq_file *seq, loff_t *pos)
1756 {
1757 struct gfs2_glock_iter *gi = seq->private;
1758 loff_t n = *pos;
1759
1760 gi->hash = 0;
1761 rcu_read_lock();
1762
1763 do {
1764 if (gfs2_glock_iter_next(gi))
1765 return NULL;
1766 } while (n--);
1767
1768 return gi->gl;
1769 }
1770
1771 static void *gfs2_glock_seq_next(struct seq_file *seq, void *iter_ptr,
1772 loff_t *pos)
1773 {
1774 struct gfs2_glock_iter *gi = seq->private;
1775
1776 (*pos)++;
1777
1778 if (gfs2_glock_iter_next(gi))
1779 return NULL;
1780
1781 return gi->gl;
1782 }
1783
1784 static void gfs2_glock_seq_stop(struct seq_file *seq, void *iter_ptr)
1785 {
1786 struct gfs2_glock_iter *gi = seq->private;
1787
1788 if (gi->gl)
1789 rcu_read_unlock();
1790 gi->gl = NULL;
1791 }
1792
1793 static int gfs2_glock_seq_show(struct seq_file *seq, void *iter_ptr)
1794 {
1795 return dump_glock(seq, iter_ptr);
1796 }
1797
1798 static const struct seq_operations gfs2_glock_seq_ops = {
1799 .start = gfs2_glock_seq_start,
1800 .next = gfs2_glock_seq_next,
1801 .stop = gfs2_glock_seq_stop,
1802 .show = gfs2_glock_seq_show,
1803 };
1804
1805 static int gfs2_debugfs_open(struct inode *inode, struct file *file)
1806 {
1807 int ret = seq_open_private(file, &gfs2_glock_seq_ops,
1808 sizeof(struct gfs2_glock_iter));
1809 if (ret == 0) {
1810 struct seq_file *seq = file->private_data;
1811 struct gfs2_glock_iter *gi = seq->private;
1812 gi->sdp = inode->i_private;
1813 }
1814 return ret;
1815 }
1816
1817 static const struct file_operations gfs2_debug_fops = {
1818 .owner = THIS_MODULE,
1819 .open = gfs2_debugfs_open,
1820 .read = seq_read,
1821 .llseek = seq_lseek,
1822 .release = seq_release_private,
1823 };
1824
1825 int gfs2_create_debugfs_file(struct gfs2_sbd *sdp)
1826 {
1827 sdp->debugfs_dir = debugfs_create_dir(sdp->sd_table_name, gfs2_root);
1828 if (!sdp->debugfs_dir)
1829 return -ENOMEM;
1830 sdp->debugfs_dentry_glocks = debugfs_create_file("glocks",
1831 S_IFREG | S_IRUGO,
1832 sdp->debugfs_dir, sdp,
1833 &gfs2_debug_fops);
1834 if (!sdp->debugfs_dentry_glocks)
1835 return -ENOMEM;
1836
1837 return 0;
1838 }
1839
1840 void gfs2_delete_debugfs_file(struct gfs2_sbd *sdp)
1841 {
1842 if (sdp && sdp->debugfs_dir) {
1843 if (sdp->debugfs_dentry_glocks) {
1844 debugfs_remove(sdp->debugfs_dentry_glocks);
1845 sdp->debugfs_dentry_glocks = NULL;
1846 }
1847 debugfs_remove(sdp->debugfs_dir);
1848 sdp->debugfs_dir = NULL;
1849 }
1850 }
1851
1852 int gfs2_register_debugfs(void)
1853 {
1854 gfs2_root = debugfs_create_dir("gfs2", NULL);
1855 return gfs2_root ? 0 : -ENOMEM;
1856 }
1857
1858 void gfs2_unregister_debugfs(void)
1859 {
1860 debugfs_remove(gfs2_root);
1861 gfs2_root = NULL;
1862 }
Linux 2.6 ibm-acpi/thinkpad-acpi driver git tree