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ARM: dts: sun6i: Add support for the status led
[linux-2.6/btrfs-unstable.git] / fs / gfs2 / glock.c
blob8f0c19d1d9439e3827ffd649e7f7d43f096afc89
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 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
11
12 #include <linux/sched.h>
13 #include <linux/slab.h>
14 #include <linux/spinlock.h>
15 #include <linux/buffer_head.h>
16 #include <linux/delay.h>
17 #include <linux/sort.h>
18 #include <linux/jhash.h>
19 #include <linux/kallsyms.h>
20 #include <linux/gfs2_ondisk.h>
21 #include <linux/list.h>
22 #include <linux/wait.h>
23 #include <linux/module.h>
24 #include <asm/uaccess.h>
25 #include <linux/seq_file.h>
26 #include <linux/debugfs.h>
27 #include <linux/kthread.h>
28 #include <linux/freezer.h>
29 #include <linux/workqueue.h>
30 #include <linux/jiffies.h>
31 #include <linux/rcupdate.h>
32 #include <linux/rculist_bl.h>
33 #include <linux/bit_spinlock.h>
34 #include <linux/percpu.h>
35 #include <linux/list_sort.h>
36 #include <linux/lockref.h>
37
38 #include "gfs2.h"
39 #include "incore.h"
40 #include "glock.h"
41 #include "glops.h"
42 #include "inode.h"
43 #include "lops.h"
44 #include "meta_io.h"
45 #include "quota.h"
46 #include "super.h"
47 #include "util.h"
48 #include "bmap.h"
49 #define CREATE_TRACE_POINTS
50 #include "trace_gfs2.h"
51
52 struct gfs2_glock_iter {
53 int hash; /* hash bucket index */
54 unsigned nhash; /* Index within current bucket */
55 struct gfs2_sbd *sdp; /* incore superblock */
56 struct gfs2_glock *gl; /* current glock struct */
57 loff_t last_pos; /* last position */
58 };
59
60 typedef void (*glock_examiner) (struct gfs2_glock * gl);
61
62 static void do_xmote(struct gfs2_glock *gl, struct gfs2_holder *gh, unsigned int target);
63
64 static struct dentry *gfs2_root;
65 static struct workqueue_struct *glock_workqueue;
66 struct workqueue_struct *gfs2_delete_workqueue;
67 static LIST_HEAD(lru_list);
68 static atomic_t lru_count = ATOMIC_INIT(0);
69 static DEFINE_SPINLOCK(lru_lock);
70
71 #define GFS2_GL_HASH_SHIFT 15
72 #define GFS2_GL_HASH_SIZE (1 << GFS2_GL_HASH_SHIFT)
73 #define GFS2_GL_HASH_MASK (GFS2_GL_HASH_SIZE - 1)
74
75 static struct hlist_bl_head gl_hash_table[GFS2_GL_HASH_SIZE];
76 static struct dentry *gfs2_root;
77
78 /**
79 * gl_hash() - Turn glock number into hash bucket number
80 * @lock: The glock number
81 *
82 * Returns: The number of the corresponding hash bucket
83 */
84
85 static unsigned int gl_hash(const struct gfs2_sbd *sdp,
86 const struct lm_lockname *name)
87 {
88 unsigned int h;
89
90 h = jhash(&name->ln_number, sizeof(u64), 0);
91 h = jhash(&name->ln_type, sizeof(unsigned int), h);
92 h = jhash(&sdp, sizeof(struct gfs2_sbd *), h);
93 h &= GFS2_GL_HASH_MASK;
94
95 return h;
96 }
97
98 static inline void spin_lock_bucket(unsigned int hash)
99 {
100 hlist_bl_lock(&gl_hash_table[hash]);
101 }
102
103 static inline void spin_unlock_bucket(unsigned int hash)
104 {
105 hlist_bl_unlock(&gl_hash_table[hash]);
106 }
107
108 static void gfs2_glock_dealloc(struct rcu_head *rcu)
109 {
110 struct gfs2_glock *gl = container_of(rcu, struct gfs2_glock, gl_rcu);
111
112 if (gl->gl_ops->go_flags & GLOF_ASPACE) {
113 kmem_cache_free(gfs2_glock_aspace_cachep, gl);
114 } else {
115 kfree(gl->gl_lksb.sb_lvbptr);
116 kmem_cache_free(gfs2_glock_cachep, gl);
117 }
118 }
119
120 void gfs2_glock_free(struct gfs2_glock *gl)
121 {
122 struct gfs2_sbd *sdp = gl->gl_sbd;
123
124 call_rcu(&gl->gl_rcu, gfs2_glock_dealloc);
125 if (atomic_dec_and_test(&sdp->sd_glock_disposal))
126 wake_up(&sdp->sd_glock_wait);
127 }
128
129 /**
130 * gfs2_glock_hold() - increment reference count on glock
131 * @gl: The glock to hold
132 *
133 */
134
135 static void gfs2_glock_hold(struct gfs2_glock *gl)
136 {
137 GLOCK_BUG_ON(gl, __lockref_is_dead(&gl->gl_lockref));
138 lockref_get(&gl->gl_lockref);
139 }
140
141 /**
142 * demote_ok - Check to see if it's ok to unlock a glock
143 * @gl: the glock
144 *
145 * Returns: 1 if it's ok
146 */
147
148 static int demote_ok(const struct gfs2_glock *gl)
149 {
150 const struct gfs2_glock_operations *glops = gl->gl_ops;
151
152 if (gl->gl_state == LM_ST_UNLOCKED)
153 return 0;
154 if (!list_empty(&gl->gl_holders))
155 return 0;
156 if (glops->go_demote_ok)
157 return glops->go_demote_ok(gl);
158 return 1;
159 }
160
161
162 void gfs2_glock_add_to_lru(struct gfs2_glock *gl)
163 {
164 spin_lock(&lru_lock);
165
166 if (!list_empty(&gl->gl_lru))
167 list_del_init(&gl->gl_lru);
168 else
169 atomic_inc(&lru_count);
170
171 list_add_tail(&gl->gl_lru, &lru_list);
172 set_bit(GLF_LRU, &gl->gl_flags);
173 spin_unlock(&lru_lock);
174 }
175
176 static void __gfs2_glock_remove_from_lru(struct gfs2_glock *gl)
177 {
178 if (!list_empty(&gl->gl_lru)) {
179 list_del_init(&gl->gl_lru);
180 atomic_dec(&lru_count);
181 clear_bit(GLF_LRU, &gl->gl_flags);
182 }
183 }
184
185 static void gfs2_glock_remove_from_lru(struct gfs2_glock *gl)
186 {
187 spin_lock(&lru_lock);
188 __gfs2_glock_remove_from_lru(gl);
189 spin_unlock(&lru_lock);
190 }
191
192 /**
193 * gfs2_glock_put() - Decrement reference count on glock
194 * @gl: The glock to put
195 *
196 */
197
198 void gfs2_glock_put(struct gfs2_glock *gl)
199 {
200 struct gfs2_sbd *sdp = gl->gl_sbd;
201 struct address_space *mapping = gfs2_glock2aspace(gl);
202
203 if (lockref_put_or_lock(&gl->gl_lockref))
204 return;
205
206 lockref_mark_dead(&gl->gl_lockref);
207
208 spin_lock(&lru_lock);
209 __gfs2_glock_remove_from_lru(gl);
210 spin_unlock(&lru_lock);
211 spin_unlock(&gl->gl_lockref.lock);
212 spin_lock_bucket(gl->gl_hash);
213 hlist_bl_del_rcu(&gl->gl_list);
214 spin_unlock_bucket(gl->gl_hash);
215 GLOCK_BUG_ON(gl, !list_empty(&gl->gl_holders));
216 GLOCK_BUG_ON(gl, mapping && mapping->nrpages);
217 trace_gfs2_glock_put(gl);
218 sdp->sd_lockstruct.ls_ops->lm_put_lock(gl);
219 }
220
221 /**
222 * search_bucket() - Find struct gfs2_glock by lock number
223 * @bucket: the bucket to search
224 * @name: The lock name
225 *
226 * Returns: NULL, or the struct gfs2_glock with the requested number
227 */
228
229 static struct gfs2_glock *search_bucket(unsigned int hash,
230 const struct gfs2_sbd *sdp,
231 const struct lm_lockname *name)
232 {
233 struct gfs2_glock *gl;
234 struct hlist_bl_node *h;
235
236 hlist_bl_for_each_entry_rcu(gl, h, &gl_hash_table[hash], gl_list) {
237 if (!lm_name_equal(&gl->gl_name, name))
238 continue;
239 if (gl->gl_sbd != sdp)
240 continue;
241 if (lockref_get_not_dead(&gl->gl_lockref))
242 return gl;
243 }
244
245 return NULL;
246 }
247
248 /**
249 * may_grant - check if its ok to grant a new lock
250 * @gl: The glock
251 * @gh: The lock request which we wish to grant
252 *
253 * Returns: true if its ok to grant the lock
254 */
255
256 static inline int may_grant(const struct gfs2_glock *gl, const struct gfs2_holder *gh)
257 {
258 const struct gfs2_holder *gh_head = list_entry(gl->gl_holders.next, const struct gfs2_holder, gh_list);
259 if ((gh->gh_state == LM_ST_EXCLUSIVE ||
260 gh_head->gh_state == LM_ST_EXCLUSIVE) && gh != gh_head)
261 return 0;
262 if (gl->gl_state == gh->gh_state)
263 return 1;
264 if (gh->gh_flags & GL_EXACT)
265 return 0;
266 if (gl->gl_state == LM_ST_EXCLUSIVE) {
267 if (gh->gh_state == LM_ST_SHARED && gh_head->gh_state == LM_ST_SHARED)
268 return 1;
269 if (gh->gh_state == LM_ST_DEFERRED && gh_head->gh_state == LM_ST_DEFERRED)
270 return 1;
271 }
272 if (gl->gl_state != LM_ST_UNLOCKED && (gh->gh_flags & LM_FLAG_ANY))
273 return 1;
274 return 0;
275 }
276
277 static void gfs2_holder_wake(struct gfs2_holder *gh)
278 {
279 clear_bit(HIF_WAIT, &gh->gh_iflags);
280 smp_mb__after_atomic();
281 wake_up_bit(&gh->gh_iflags, HIF_WAIT);
282 }
283
284 /**
285 * do_error - Something unexpected has happened during a lock request
286 *
287 */
288
289 static inline void do_error(struct gfs2_glock *gl, const int ret)
290 {
291 struct gfs2_holder *gh, *tmp;
292
293 list_for_each_entry_safe(gh, tmp, &gl->gl_holders, gh_list) {
294 if (test_bit(HIF_HOLDER, &gh->gh_iflags))
295 continue;
296 if (ret & LM_OUT_ERROR)
297 gh->gh_error = -EIO;
298 else if (gh->gh_flags & (LM_FLAG_TRY | LM_FLAG_TRY_1CB))
299 gh->gh_error = GLR_TRYFAILED;
300 else
301 continue;
302 list_del_init(&gh->gh_list);
303 trace_gfs2_glock_queue(gh, 0);
304 gfs2_holder_wake(gh);
305 }
306 }
307
308 /**
309 * do_promote - promote as many requests as possible on the current queue
310 * @gl: The glock
311 *
312 * Returns: 1 if there is a blocked holder at the head of the list, or 2
313 * if a type specific operation is underway.
314 */
315
316 static int do_promote(struct gfs2_glock *gl)
317 __releases(&gl->gl_spin)
318 __acquires(&gl->gl_spin)
319 {
320 const struct gfs2_glock_operations *glops = gl->gl_ops;
321 struct gfs2_holder *gh, *tmp;
322 int ret;
323
324 restart:
325 list_for_each_entry_safe(gh, tmp, &gl->gl_holders, gh_list) {
326 if (test_bit(HIF_HOLDER, &gh->gh_iflags))
327 continue;
328 if (may_grant(gl, gh)) {
329 if (gh->gh_list.prev == &gl->gl_holders &&
330 glops->go_lock) {
331 spin_unlock(&gl->gl_spin);
332 /* FIXME: eliminate this eventually */
333 ret = glops->go_lock(gh);
334 spin_lock(&gl->gl_spin);
335 if (ret) {
336 if (ret == 1)
337 return 2;
338 gh->gh_error = ret;
339 list_del_init(&gh->gh_list);
340 trace_gfs2_glock_queue(gh, 0);
341 gfs2_holder_wake(gh);
342 goto restart;
343 }
344 set_bit(HIF_HOLDER, &gh->gh_iflags);
345 trace_gfs2_promote(gh, 1);
346 gfs2_holder_wake(gh);
347 goto restart;
348 }
349 set_bit(HIF_HOLDER, &gh->gh_iflags);
350 trace_gfs2_promote(gh, 0);
351 gfs2_holder_wake(gh);
352 continue;
353 }
354 if (gh->gh_list.prev == &gl->gl_holders)
355 return 1;
356 do_error(gl, 0);
357 break;
358 }
359 return 0;
360 }
361
362 /**
363 * find_first_waiter - find the first gh that's waiting for the glock
364 * @gl: the glock
365 */
366
367 static inline struct gfs2_holder *find_first_waiter(const struct gfs2_glock *gl)
368 {
369 struct gfs2_holder *gh;
370
371 list_for_each_entry(gh, &gl->gl_holders, gh_list) {
372 if (!test_bit(HIF_HOLDER, &gh->gh_iflags))
373 return gh;
374 }
375 return NULL;
376 }
377
378 /**
379 * state_change - record that the glock is now in a different state
380 * @gl: the glock
381 * @new_state the new state
382 *
383 */
384
385 static void state_change(struct gfs2_glock *gl, unsigned int new_state)
386 {
387 int held1, held2;
388
389 held1 = (gl->gl_state != LM_ST_UNLOCKED);
390 held2 = (new_state != LM_ST_UNLOCKED);
391
392 if (held1 != held2) {
393 GLOCK_BUG_ON(gl, __lockref_is_dead(&gl->gl_lockref));
394 if (held2)
395 gl->gl_lockref.count++;
396 else
397 gl->gl_lockref.count--;
398 }
399 if (held1 && held2 && list_empty(&gl->gl_holders))
400 clear_bit(GLF_QUEUED, &gl->gl_flags);
401
402 if (new_state != gl->gl_target)
403 /* shorten our minimum hold time */
404 gl->gl_hold_time = max(gl->gl_hold_time - GL_GLOCK_HOLD_DECR,
405 GL_GLOCK_MIN_HOLD);
406 gl->gl_state = new_state;
407 gl->gl_tchange = jiffies;
408 }
409
410 static void gfs2_demote_wake(struct gfs2_glock *gl)
411 {
412 gl->gl_demote_state = LM_ST_EXCLUSIVE;
413 clear_bit(GLF_DEMOTE, &gl->gl_flags);
414 smp_mb__after_atomic();
415 wake_up_bit(&gl->gl_flags, GLF_DEMOTE);
416 }
417
418 /**
419 * finish_xmote - The DLM has replied to one of our lock requests
420 * @gl: The glock
421 * @ret: The status from the DLM
422 *
423 */
424
425 static void finish_xmote(struct gfs2_glock *gl, unsigned int ret)
426 {
427 const struct gfs2_glock_operations *glops = gl->gl_ops;
428 struct gfs2_holder *gh;
429 unsigned state = ret & LM_OUT_ST_MASK;
430 int rv;
431
432 spin_lock(&gl->gl_spin);
433 trace_gfs2_glock_state_change(gl, state);
434 state_change(gl, state);
435 gh = find_first_waiter(gl);
436
437 /* Demote to UN request arrived during demote to SH or DF */
438 if (test_bit(GLF_DEMOTE_IN_PROGRESS, &gl->gl_flags) &&
439 state != LM_ST_UNLOCKED && gl->gl_demote_state == LM_ST_UNLOCKED)
440 gl->gl_target = LM_ST_UNLOCKED;
441
442 /* Check for state != intended state */
443 if (unlikely(state != gl->gl_target)) {
444 if (gh && !test_bit(GLF_DEMOTE_IN_PROGRESS, &gl->gl_flags)) {
445 /* move to back of queue and try next entry */
446 if (ret & LM_OUT_CANCELED) {
447 if ((gh->gh_flags & LM_FLAG_PRIORITY) == 0)
448 list_move_tail(&gh->gh_list, &gl->gl_holders);
449 gh = find_first_waiter(gl);
450 gl->gl_target = gh->gh_state;
451 goto retry;
452 }
453 /* Some error or failed "try lock" - report it */
454 if ((ret & LM_OUT_ERROR) ||
455 (gh->gh_flags & (LM_FLAG_TRY | LM_FLAG_TRY_1CB))) {
456 gl->gl_target = gl->gl_state;
457 do_error(gl, ret);
458 goto out;
459 }
460 }
461 switch(state) {
462 /* Unlocked due to conversion deadlock, try again */
463 case LM_ST_UNLOCKED:
464 retry:
465 do_xmote(gl, gh, gl->gl_target);
466 break;
467 /* Conversion fails, unlock and try again */
468 case LM_ST_SHARED:
469 case LM_ST_DEFERRED:
470 do_xmote(gl, gh, LM_ST_UNLOCKED);
471 break;
472 default: /* Everything else */
473 pr_err("wanted %u got %u\n", gl->gl_target, state);
474 GLOCK_BUG_ON(gl, 1);
475 }
476 spin_unlock(&gl->gl_spin);
477 return;
478 }
479
480 /* Fast path - we got what we asked for */
481 if (test_and_clear_bit(GLF_DEMOTE_IN_PROGRESS, &gl->gl_flags))
482 gfs2_demote_wake(gl);
483 if (state != LM_ST_UNLOCKED) {
484 if (glops->go_xmote_bh) {
485 spin_unlock(&gl->gl_spin);
486 rv = glops->go_xmote_bh(gl, gh);
487 spin_lock(&gl->gl_spin);
488 if (rv) {
489 do_error(gl, rv);
490 goto out;
491 }
492 }
493 rv = do_promote(gl);
494 if (rv == 2)
495 goto out_locked;
496 }
497 out:
498 clear_bit(GLF_LOCK, &gl->gl_flags);
499 out_locked:
500 spin_unlock(&gl->gl_spin);
501 }
502
503 /**
504 * do_xmote - Calls the DLM to change the state of a lock
505 * @gl: The lock state
506 * @gh: The holder (only for promotes)
507 * @target: The target lock state
508 *
509 */
510
511 static void do_xmote(struct gfs2_glock *gl, struct gfs2_holder *gh, unsigned int target)
512 __releases(&gl->gl_spin)
513 __acquires(&gl->gl_spin)
514 {
515 const struct gfs2_glock_operations *glops = gl->gl_ops;
516 struct gfs2_sbd *sdp = gl->gl_sbd;
517 unsigned int lck_flags = gh ? gh->gh_flags : 0;
518 int ret;
519
520 lck_flags &= (LM_FLAG_TRY | LM_FLAG_TRY_1CB | LM_FLAG_NOEXP |
521 LM_FLAG_PRIORITY);
522 GLOCK_BUG_ON(gl, gl->gl_state == target);
523 GLOCK_BUG_ON(gl, gl->gl_state == gl->gl_target);
524 if ((target == LM_ST_UNLOCKED || target == LM_ST_DEFERRED) &&
525 glops->go_inval) {
526 set_bit(GLF_INVALIDATE_IN_PROGRESS, &gl->gl_flags);
527 do_error(gl, 0); /* Fail queued try locks */
528 }
529 gl->gl_req = target;
530 set_bit(GLF_BLOCKING, &gl->gl_flags);
531 if ((gl->gl_req == LM_ST_UNLOCKED) ||
532 (gl->gl_state == LM_ST_EXCLUSIVE) ||
533 (lck_flags & (LM_FLAG_TRY|LM_FLAG_TRY_1CB)))
534 clear_bit(GLF_BLOCKING, &gl->gl_flags);
535 spin_unlock(&gl->gl_spin);
536 if (glops->go_sync)
537 glops->go_sync(gl);
538 if (test_bit(GLF_INVALIDATE_IN_PROGRESS, &gl->gl_flags))
539 glops->go_inval(gl, target == LM_ST_DEFERRED ? 0 : DIO_METADATA);
540 clear_bit(GLF_INVALIDATE_IN_PROGRESS, &gl->gl_flags);
541
542 gfs2_glock_hold(gl);
543 if (sdp->sd_lockstruct.ls_ops->lm_lock) {
544 /* lock_dlm */
545 ret = sdp->sd_lockstruct.ls_ops->lm_lock(gl, target, lck_flags);
546 if (ret) {
547 pr_err("lm_lock ret %d\n", ret);
548 GLOCK_BUG_ON(gl, 1);
549 }
550 } else { /* lock_nolock */
551 finish_xmote(gl, target);
552 if (queue_delayed_work(glock_workqueue, &gl->gl_work, 0) == 0)
553 gfs2_glock_put(gl);
554 }
555
556 spin_lock(&gl->gl_spin);
557 }
558
559 /**
560 * find_first_holder - find the first "holder" gh
561 * @gl: the glock
562 */
563
564 static inline struct gfs2_holder *find_first_holder(const struct gfs2_glock *gl)
565 {
566 struct gfs2_holder *gh;
567
568 if (!list_empty(&gl->gl_holders)) {
569 gh = list_entry(gl->gl_holders.next, struct gfs2_holder, gh_list);
570 if (test_bit(HIF_HOLDER, &gh->gh_iflags))
571 return gh;
572 }
573 return NULL;
574 }
575
576 /**
577 * run_queue - do all outstanding tasks related to a glock
578 * @gl: The glock in question
579 * @nonblock: True if we must not block in run_queue
580 *
581 */
582
583 static void run_queue(struct gfs2_glock *gl, const int nonblock)
584 __releases(&gl->gl_spin)
585 __acquires(&gl->gl_spin)
586 {
587 struct gfs2_holder *gh = NULL;
588 int ret;
589
590 if (test_and_set_bit(GLF_LOCK, &gl->gl_flags))
591 return;
592
593 GLOCK_BUG_ON(gl, test_bit(GLF_DEMOTE_IN_PROGRESS, &gl->gl_flags));
594
595 if (test_bit(GLF_DEMOTE, &gl->gl_flags) &&
596 gl->gl_demote_state != gl->gl_state) {
597 if (find_first_holder(gl))
598 goto out_unlock;
599 if (nonblock)
600 goto out_sched;
601 set_bit(GLF_DEMOTE_IN_PROGRESS, &gl->gl_flags);
602 GLOCK_BUG_ON(gl, gl->gl_demote_state == LM_ST_EXCLUSIVE);
603 gl->gl_target = gl->gl_demote_state;
604 } else {
605 if (test_bit(GLF_DEMOTE, &gl->gl_flags))
606 gfs2_demote_wake(gl);
607 ret = do_promote(gl);
608 if (ret == 0)
609 goto out_unlock;
610 if (ret == 2)
611 goto out;
612 gh = find_first_waiter(gl);
613 gl->gl_target = gh->gh_state;
614 if (!(gh->gh_flags & (LM_FLAG_TRY | LM_FLAG_TRY_1CB)))
615 do_error(gl, 0); /* Fail queued try locks */
616 }
617 do_xmote(gl, gh, gl->gl_target);
618 out:
619 return;
620
621 out_sched:
622 clear_bit(GLF_LOCK, &gl->gl_flags);
623 smp_mb__after_atomic();
624 gl->gl_lockref.count++;
625 if (queue_delayed_work(glock_workqueue, &gl->gl_work, 0) == 0)
626 gl->gl_lockref.count--;
627 return;
628
629 out_unlock:
630 clear_bit(GLF_LOCK, &gl->gl_flags);
631 smp_mb__after_atomic();
632 return;
633 }
634
635 static void delete_work_func(struct work_struct *work)
636 {
637 struct gfs2_glock *gl = container_of(work, struct gfs2_glock, gl_delete);
638 struct gfs2_sbd *sdp = gl->gl_sbd;
639 struct gfs2_inode *ip;
640 struct inode *inode;
641 u64 no_addr = gl->gl_name.ln_number;
642
643 ip = gl->gl_object;
644 /* Note: Unsafe to dereference ip as we don't hold right refs/locks */
645
646 if (ip)
647 inode = gfs2_ilookup(sdp->sd_vfs, no_addr, 1);
648 else
649 inode = gfs2_lookup_by_inum(sdp, no_addr, NULL, GFS2_BLKST_UNLINKED);
650 if (inode && !IS_ERR(inode)) {
651 d_prune_aliases(inode);
652 iput(inode);
653 }
654 gfs2_glock_put(gl);
655 }
656
657 static void glock_work_func(struct work_struct *work)
658 {
659 unsigned long delay = 0;
660 struct gfs2_glock *gl = container_of(work, struct gfs2_glock, gl_work.work);
661 int drop_ref = 0;
662
663 if (test_and_clear_bit(GLF_REPLY_PENDING, &gl->gl_flags)) {
664 finish_xmote(gl, gl->gl_reply);
665 drop_ref = 1;
666 }
667 spin_lock(&gl->gl_spin);
668 if (test_bit(GLF_PENDING_DEMOTE, &gl->gl_flags) &&
669 gl->gl_state != LM_ST_UNLOCKED &&
670 gl->gl_demote_state != LM_ST_EXCLUSIVE) {
671 unsigned long holdtime, now = jiffies;
672
673 holdtime = gl->gl_tchange + gl->gl_hold_time;
674 if (time_before(now, holdtime))
675 delay = holdtime - now;
676
677 if (!delay) {
678 clear_bit(GLF_PENDING_DEMOTE, &gl->gl_flags);
679 set_bit(GLF_DEMOTE, &gl->gl_flags);
680 }
681 }
682 run_queue(gl, 0);
683 spin_unlock(&gl->gl_spin);
684 if (!delay)
685 gfs2_glock_put(gl);
686 else {
687 if (gl->gl_name.ln_type != LM_TYPE_INODE)
688 delay = 0;
689 if (queue_delayed_work(glock_workqueue, &gl->gl_work, delay) == 0)
690 gfs2_glock_put(gl);
691 }
692 if (drop_ref)
693 gfs2_glock_put(gl);
694 }
695
696 /**
697 * gfs2_glock_get() - Get a glock, or create one if one doesn't exist
698 * @sdp: The GFS2 superblock
699 * @number: the lock number
700 * @glops: The glock_operations to use
701 * @create: If 0, don't create the glock if it doesn't exist
702 * @glp: the glock is returned here
703 *
704 * This does not lock a glock, just finds/creates structures for one.
705 *
706 * Returns: errno
707 */
708
709 int gfs2_glock_get(struct gfs2_sbd *sdp, u64 number,
710 const struct gfs2_glock_operations *glops, int create,
711 struct gfs2_glock **glp)
712 {
713 struct super_block *s = sdp->sd_vfs;
714 struct lm_lockname name = { .ln_number = number, .ln_type = glops->go_type };
715 struct gfs2_glock *gl, *tmp;
716 unsigned int hash = gl_hash(sdp, &name);
717 struct address_space *mapping;
718 struct kmem_cache *cachep;
719
720 rcu_read_lock();
721 gl = search_bucket(hash, sdp, &name);
722 rcu_read_unlock();
723
724 *glp = gl;
725 if (gl)
726 return 0;
727 if (!create)
728 return -ENOENT;
729
730 if (glops->go_flags & GLOF_ASPACE)
731 cachep = gfs2_glock_aspace_cachep;
732 else
733 cachep = gfs2_glock_cachep;
734 gl = kmem_cache_alloc(cachep, GFP_NOFS);
735 if (!gl)
736 return -ENOMEM;
737
738 memset(&gl->gl_lksb, 0, sizeof(struct dlm_lksb));
739
740 if (glops->go_flags & GLOF_LVB) {
741 gl->gl_lksb.sb_lvbptr = kzalloc(GFS2_MIN_LVB_SIZE, GFP_NOFS);
742 if (!gl->gl_lksb.sb_lvbptr) {
743 kmem_cache_free(cachep, gl);
744 return -ENOMEM;
745 }
746 }
747
748 atomic_inc(&sdp->sd_glock_disposal);
749 gl->gl_sbd = sdp;
750 gl->gl_flags = 0;
751 gl->gl_name = name;
752 gl->gl_lockref.count = 1;
753 gl->gl_state = LM_ST_UNLOCKED;
754 gl->gl_target = LM_ST_UNLOCKED;
755 gl->gl_demote_state = LM_ST_EXCLUSIVE;
756 gl->gl_hash = hash;
757 gl->gl_ops = glops;
758 gl->gl_dstamp = ktime_set(0, 0);
759 preempt_disable();
760 /* We use the global stats to estimate the initial per-glock stats */
761 gl->gl_stats = this_cpu_ptr(sdp->sd_lkstats)->lkstats[glops->go_type];
762 preempt_enable();
763 gl->gl_stats.stats[GFS2_LKS_DCOUNT] = 0;
764 gl->gl_stats.stats[GFS2_LKS_QCOUNT] = 0;
765 gl->gl_tchange = jiffies;
766 gl->gl_object = NULL;
767 gl->gl_hold_time = GL_GLOCK_DFT_HOLD;
768 INIT_DELAYED_WORK(&gl->gl_work, glock_work_func);
769 INIT_WORK(&gl->gl_delete, delete_work_func);
770
771 mapping = gfs2_glock2aspace(gl);
772 if (mapping) {
773 mapping->a_ops = &gfs2_meta_aops;
774 mapping->host = s->s_bdev->bd_inode;
775 mapping->flags = 0;
776 mapping_set_gfp_mask(mapping, GFP_NOFS);
777 mapping->private_data = NULL;
778 mapping->backing_dev_info = s->s_bdi;
779 mapping->writeback_index = 0;
780 }
781
782 spin_lock_bucket(hash);
783 tmp = search_bucket(hash, sdp, &name);
784 if (tmp) {
785 spin_unlock_bucket(hash);
786 kfree(gl->gl_lksb.sb_lvbptr);
787 kmem_cache_free(cachep, gl);
788 atomic_dec(&sdp->sd_glock_disposal);
789 gl = tmp;
790 } else {
791 hlist_bl_add_head_rcu(&gl->gl_list, &gl_hash_table[hash]);
792 spin_unlock_bucket(hash);
793 }
794
795 *glp = gl;
796
797 return 0;
798 }
799
800 /**
801 * gfs2_holder_init - initialize a struct gfs2_holder in the default way
802 * @gl: the glock
803 * @state: the state we're requesting
804 * @flags: the modifier flags
805 * @gh: the holder structure
806 *
807 */
808
809 void gfs2_holder_init(struct gfs2_glock *gl, unsigned int state, unsigned flags,
810 struct gfs2_holder *gh)
811 {
812 INIT_LIST_HEAD(&gh->gh_list);
813 gh->gh_gl = gl;
814 gh->gh_ip = _RET_IP_;
815 gh->gh_owner_pid = get_pid(task_pid(current));
816 gh->gh_state = state;
817 gh->gh_flags = flags;
818 gh->gh_error = 0;
819 gh->gh_iflags = 0;
820 gfs2_glock_hold(gl);
821 }
822
823 /**
824 * gfs2_holder_reinit - reinitialize a struct gfs2_holder so we can requeue it
825 * @state: the state we're requesting
826 * @flags: the modifier flags
827 * @gh: the holder structure
828 *
829 * Don't mess with the glock.
830 *
831 */
832
833 void gfs2_holder_reinit(unsigned int state, unsigned flags, struct gfs2_holder *gh)
834 {
835 gh->gh_state = state;
836 gh->gh_flags = flags;
837 gh->gh_iflags = 0;
838 gh->gh_ip = _RET_IP_;
839 if (gh->gh_owner_pid)
840 put_pid(gh->gh_owner_pid);
841 gh->gh_owner_pid = get_pid(task_pid(current));
842 }
843
844 /**
845 * gfs2_holder_uninit - uninitialize a holder structure (drop glock reference)
846 * @gh: the holder structure
847 *
848 */
849
850 void gfs2_holder_uninit(struct gfs2_holder *gh)
851 {
852 put_pid(gh->gh_owner_pid);
853 gfs2_glock_put(gh->gh_gl);
854 gh->gh_gl = NULL;
855 gh->gh_ip = 0;
856 }
857
858 /**
859 * gfs2_glock_wait - wait on a glock acquisition
860 * @gh: the glock holder
861 *
862 * Returns: 0 on success
863 */
864
865 int gfs2_glock_wait(struct gfs2_holder *gh)
866 {
867 unsigned long time1 = jiffies;
868
869 might_sleep();
870 wait_on_bit(&gh->gh_iflags, HIF_WAIT, TASK_UNINTERRUPTIBLE);
871 if (time_after(jiffies, time1 + HZ)) /* have we waited > a second? */
872 /* Lengthen the minimum hold time. */
873 gh->gh_gl->gl_hold_time = min(gh->gh_gl->gl_hold_time +
874 GL_GLOCK_HOLD_INCR,
875 GL_GLOCK_MAX_HOLD);
876 return gh->gh_error;
877 }
878
879 /**
880 * handle_callback - process a demote request
881 * @gl: the glock
882 * @state: the state the caller wants us to change to
883 *
884 * There are only two requests that we are going to see in actual
885 * practise: LM_ST_SHARED and LM_ST_UNLOCKED
886 */
887
888 static void handle_callback(struct gfs2_glock *gl, unsigned int state,
889 unsigned long delay, bool remote)
890 {
891 int bit = delay ? GLF_PENDING_DEMOTE : GLF_DEMOTE;
892
893 set_bit(bit, &gl->gl_flags);
894 if (gl->gl_demote_state == LM_ST_EXCLUSIVE) {
895 gl->gl_demote_state = state;
896 gl->gl_demote_time = jiffies;
897 } else if (gl->gl_demote_state != LM_ST_UNLOCKED &&
898 gl->gl_demote_state != state) {
899 gl->gl_demote_state = LM_ST_UNLOCKED;
900 }
901 if (gl->gl_ops->go_callback)
902 gl->gl_ops->go_callback(gl, remote);
903 trace_gfs2_demote_rq(gl, remote);
904 }
905
906 void gfs2_print_dbg(struct seq_file *seq, const char *fmt, ...)
907 {
908 struct va_format vaf;
909 va_list args;
910
911 va_start(args, fmt);
912
913 if (seq) {
914 seq_vprintf(seq, fmt, args);
915 } else {
916 vaf.fmt = fmt;
917 vaf.va = &args;
918
919 pr_err("%pV", &vaf);
920 }
921
922 va_end(args);
923 }
924
925 /**
926 * add_to_queue - Add a holder to the wait queue (but look for recursion)
927 * @gh: the holder structure to add
928 *
929 * Eventually we should move the recursive locking trap to a
930 * debugging option or something like that. This is the fast
931 * path and needs to have the minimum number of distractions.
932 *
933 */
934
935 static inline void add_to_queue(struct gfs2_holder *gh)
936 __releases(&gl->gl_spin)
937 __acquires(&gl->gl_spin)
938 {
939 struct gfs2_glock *gl = gh->gh_gl;
940 struct gfs2_sbd *sdp = gl->gl_sbd;
941 struct list_head *insert_pt = NULL;
942 struct gfs2_holder *gh2;
943 int try_futile = 0;
944
945 BUG_ON(gh->gh_owner_pid == NULL);
946 if (test_and_set_bit(HIF_WAIT, &gh->gh_iflags))
947 BUG();
948
949 if (gh->gh_flags & (LM_FLAG_TRY | LM_FLAG_TRY_1CB)) {
950 if (test_bit(GLF_LOCK, &gl->gl_flags))
951 try_futile = !may_grant(gl, gh);
952 if (test_bit(GLF_INVALIDATE_IN_PROGRESS, &gl->gl_flags))
953 goto fail;
954 }
955
956 list_for_each_entry(gh2, &gl->gl_holders, gh_list) {
957 if (unlikely(gh2->gh_owner_pid == gh->gh_owner_pid &&
958 (gh->gh_gl->gl_ops->go_type != LM_TYPE_FLOCK)))
959 goto trap_recursive;
960 if (try_futile &&
961 !(gh2->gh_flags & (LM_FLAG_TRY | LM_FLAG_TRY_1CB))) {
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 gfs2_glstats_inc(gl, GFS2_LKS_QCOUNT);
975 gfs2_sbstats_inc(gl, GFS2_LKS_QCOUNT);
976 if (likely(insert_pt == NULL)) {
977 list_add_tail(&gh->gh_list, &gl->gl_holders);
978 if (unlikely(gh->gh_flags & LM_FLAG_PRIORITY))
979 goto do_cancel;
980 return;
981 }
982 list_add_tail(&gh->gh_list, insert_pt);
983 do_cancel:
984 gh = list_entry(gl->gl_holders.next, struct gfs2_holder, gh_list);
985 if (!(gh->gh_flags & LM_FLAG_PRIORITY)) {
986 spin_unlock(&gl->gl_spin);
987 if (sdp->sd_lockstruct.ls_ops->lm_cancel)
988 sdp->sd_lockstruct.ls_ops->lm_cancel(gl);
989 spin_lock(&gl->gl_spin);
990 }
991 return;
992
993 trap_recursive:
994 pr_err("original: %pSR\n", (void *)gh2->gh_ip);
995 pr_err("pid: %d\n", pid_nr(gh2->gh_owner_pid));
996 pr_err("lock type: %d req lock state : %d\n",
997 gh2->gh_gl->gl_name.ln_type, gh2->gh_state);
998 pr_err("new: %pSR\n", (void *)gh->gh_ip);
999 pr_err("pid: %d\n", pid_nr(gh->gh_owner_pid));
1000 pr_err("lock type: %d req lock state : %d\n",
1001 gh->gh_gl->gl_name.ln_type, gh->gh_state);
1002 gfs2_dump_glock(NULL, gl);
1003 BUG();
1004 }
1005
1006 /**
1007 * gfs2_glock_nq - enqueue a struct gfs2_holder onto a glock (acquire a glock)
1008 * @gh: the holder structure
1009 *
1010 * if (gh->gh_flags & GL_ASYNC), this never returns an error
1011 *
1012 * Returns: 0, GLR_TRYFAILED, or errno on failure
1013 */
1014
1015 int gfs2_glock_nq(struct gfs2_holder *gh)
1016 {
1017 struct gfs2_glock *gl = gh->gh_gl;
1018 struct gfs2_sbd *sdp = gl->gl_sbd;
1019 int error = 0;
1020
1021 if (unlikely(test_bit(SDF_SHUTDOWN, &sdp->sd_flags)))
1022 return -EIO;
1023
1024 if (test_bit(GLF_LRU, &gl->gl_flags))
1025 gfs2_glock_remove_from_lru(gl);
1026
1027 spin_lock(&gl->gl_spin);
1028 add_to_queue(gh);
1029 if (unlikely((LM_FLAG_NOEXP & gh->gh_flags) &&
1030 test_and_clear_bit(GLF_FROZEN, &gl->gl_flags))) {
1031 set_bit(GLF_REPLY_PENDING, &gl->gl_flags);
1032 gl->gl_lockref.count++;
1033 if (queue_delayed_work(glock_workqueue, &gl->gl_work, 0) == 0)
1034 gl->gl_lockref.count--;
1035 }
1036 run_queue(gl, 1);
1037 spin_unlock(&gl->gl_spin);
1038
1039 if (!(gh->gh_flags & GL_ASYNC))
1040 error = gfs2_glock_wait(gh);
1041
1042 return error;
1043 }
1044
1045 /**
1046 * gfs2_glock_poll - poll to see if an async request has been completed
1047 * @gh: the holder
1048 *
1049 * Returns: 1 if the request is ready to be gfs2_glock_wait()ed on
1050 */
1051
1052 int gfs2_glock_poll(struct gfs2_holder *gh)
1053 {
1054 return test_bit(HIF_WAIT, &gh->gh_iflags) ? 0 : 1;
1055 }
1056
1057 /**
1058 * gfs2_glock_dq - dequeue a struct gfs2_holder from a glock (release a glock)
1059 * @gh: the glock holder
1060 *
1061 */
1062
1063 void gfs2_glock_dq(struct gfs2_holder *gh)
1064 {
1065 struct gfs2_glock *gl = gh->gh_gl;
1066 const struct gfs2_glock_operations *glops = gl->gl_ops;
1067 unsigned delay = 0;
1068 int fast_path = 0;
1069
1070 spin_lock(&gl->gl_spin);
1071 if (gh->gh_flags & GL_NOCACHE)
1072 handle_callback(gl, LM_ST_UNLOCKED, 0, false);
1073
1074 list_del_init(&gh->gh_list);
1075 if (find_first_holder(gl) == NULL) {
1076 if (glops->go_unlock) {
1077 GLOCK_BUG_ON(gl, test_and_set_bit(GLF_LOCK, &gl->gl_flags));
1078 spin_unlock(&gl->gl_spin);
1079 glops->go_unlock(gh);
1080 spin_lock(&gl->gl_spin);
1081 clear_bit(GLF_LOCK, &gl->gl_flags);
1082 }
1083 if (list_empty(&gl->gl_holders) &&
1084 !test_bit(GLF_PENDING_DEMOTE, &gl->gl_flags) &&
1085 !test_bit(GLF_DEMOTE, &gl->gl_flags))
1086 fast_path = 1;
1087 }
1088 if (!test_bit(GLF_LFLUSH, &gl->gl_flags) && demote_ok(gl))
1089 gfs2_glock_add_to_lru(gl);
1090
1091 trace_gfs2_glock_queue(gh, 0);
1092 spin_unlock(&gl->gl_spin);
1093 if (likely(fast_path))
1094 return;
1095
1096 gfs2_glock_hold(gl);
1097 if (test_bit(GLF_PENDING_DEMOTE, &gl->gl_flags) &&
1098 !test_bit(GLF_DEMOTE, &gl->gl_flags) &&
1099 gl->gl_name.ln_type == LM_TYPE_INODE)
1100 delay = gl->gl_hold_time;
1101 if (queue_delayed_work(glock_workqueue, &gl->gl_work, delay) == 0)
1102 gfs2_glock_put(gl);
1103 }
1104
1105 void gfs2_glock_dq_wait(struct gfs2_holder *gh)
1106 {
1107 struct gfs2_glock *gl = gh->gh_gl;
1108 gfs2_glock_dq(gh);
1109 might_sleep();
1110 wait_on_bit(&gl->gl_flags, GLF_DEMOTE, TASK_UNINTERRUPTIBLE);
1111 }
1112
1113 /**
1114 * gfs2_glock_dq_uninit - dequeue a holder from a glock and initialize it
1115 * @gh: the holder structure
1116 *
1117 */
1118
1119 void gfs2_glock_dq_uninit(struct gfs2_holder *gh)
1120 {
1121 gfs2_glock_dq(gh);
1122 gfs2_holder_uninit(gh);
1123 }
1124
1125 /**
1126 * gfs2_glock_nq_num - acquire a glock based on lock number
1127 * @sdp: the filesystem
1128 * @number: the lock number
1129 * @glops: the glock operations for the type of glock
1130 * @state: the state to acquire the glock in
1131 * @flags: modifier flags for the acquisition
1132 * @gh: the struct gfs2_holder
1133 *
1134 * Returns: errno
1135 */
1136
1137 int gfs2_glock_nq_num(struct gfs2_sbd *sdp, u64 number,
1138 const struct gfs2_glock_operations *glops,
1139 unsigned int state, int flags, struct gfs2_holder *gh)
1140 {
1141 struct gfs2_glock *gl;
1142 int error;
1143
1144 error = gfs2_glock_get(sdp, number, glops, CREATE, &gl);
1145 if (!error) {
1146 error = gfs2_glock_nq_init(gl, state, flags, gh);
1147 gfs2_glock_put(gl);
1148 }
1149
1150 return error;
1151 }
1152
1153 /**
1154 * glock_compare - Compare two struct gfs2_glock structures for sorting
1155 * @arg_a: the first structure
1156 * @arg_b: the second structure
1157 *
1158 */
1159
1160 static int glock_compare(const void *arg_a, const void *arg_b)
1161 {
1162 const struct gfs2_holder *gh_a = *(const struct gfs2_holder **)arg_a;
1163 const struct gfs2_holder *gh_b = *(const struct gfs2_holder **)arg_b;
1164 const struct lm_lockname *a = &gh_a->gh_gl->gl_name;
1165 const struct lm_lockname *b = &gh_b->gh_gl->gl_name;
1166
1167 if (a->ln_number > b->ln_number)
1168 return 1;
1169 if (a->ln_number < b->ln_number)
1170 return -1;
1171 BUG_ON(gh_a->gh_gl->gl_ops->go_type == gh_b->gh_gl->gl_ops->go_type);
1172 return 0;
1173 }
1174
1175 /**
1176 * nq_m_sync - synchonously acquire more than one glock in deadlock free order
1177 * @num_gh: the number of structures
1178 * @ghs: an array of struct gfs2_holder structures
1179 *
1180 * Returns: 0 on success (all glocks acquired),
1181 * errno on failure (no glocks acquired)
1182 */
1183
1184 static int nq_m_sync(unsigned int num_gh, struct gfs2_holder *ghs,
1185 struct gfs2_holder **p)
1186 {
1187 unsigned int x;
1188 int error = 0;
1189
1190 for (x = 0; x < num_gh; x++)
1191 p[x] = &ghs[x];
1192
1193 sort(p, num_gh, sizeof(struct gfs2_holder *), glock_compare, NULL);
1194
1195 for (x = 0; x < num_gh; x++) {
1196 p[x]->gh_flags &= ~(LM_FLAG_TRY | GL_ASYNC);
1197
1198 error = gfs2_glock_nq(p[x]);
1199 if (error) {
1200 while (x--)
1201 gfs2_glock_dq(p[x]);
1202 break;
1203 }
1204 }
1205
1206 return error;
1207 }
1208
1209 /**
1210 * gfs2_glock_nq_m - acquire multiple glocks
1211 * @num_gh: the number of structures
1212 * @ghs: an array of struct gfs2_holder structures
1213 *
1214 *
1215 * Returns: 0 on success (all glocks acquired),
1216 * errno on failure (no glocks acquired)
1217 */
1218
1219 int gfs2_glock_nq_m(unsigned int num_gh, struct gfs2_holder *ghs)
1220 {
1221 struct gfs2_holder *tmp[4];
1222 struct gfs2_holder **pph = tmp;
1223 int error = 0;
1224
1225 switch(num_gh) {
1226 case 0:
1227 return 0;
1228 case 1:
1229 ghs->gh_flags &= ~(LM_FLAG_TRY | GL_ASYNC);
1230 return gfs2_glock_nq(ghs);
1231 default:
1232 if (num_gh <= 4)
1233 break;
1234 pph = kmalloc(num_gh * sizeof(struct gfs2_holder *), GFP_NOFS);
1235 if (!pph)
1236 return -ENOMEM;
1237 }
1238
1239 error = nq_m_sync(num_gh, ghs, pph);
1240
1241 if (pph != tmp)
1242 kfree(pph);
1243
1244 return error;
1245 }
1246
1247 /**
1248 * gfs2_glock_dq_m - release multiple glocks
1249 * @num_gh: the number of structures
1250 * @ghs: an array of struct gfs2_holder structures
1251 *
1252 */
1253
1254 void gfs2_glock_dq_m(unsigned int num_gh, struct gfs2_holder *ghs)
1255 {
1256 while (num_gh--)
1257 gfs2_glock_dq(&ghs[num_gh]);
1258 }
1259
1260 void gfs2_glock_cb(struct gfs2_glock *gl, unsigned int state)
1261 {
1262 unsigned long delay = 0;
1263 unsigned long holdtime;
1264 unsigned long now = jiffies;
1265
1266 gfs2_glock_hold(gl);
1267 holdtime = gl->gl_tchange + gl->gl_hold_time;
1268 if (test_bit(GLF_QUEUED, &gl->gl_flags) &&
1269 gl->gl_name.ln_type == LM_TYPE_INODE) {
1270 if (time_before(now, holdtime))
1271 delay = holdtime - now;
1272 if (test_bit(GLF_REPLY_PENDING, &gl->gl_flags))
1273 delay = gl->gl_hold_time;
1274 }
1275
1276 spin_lock(&gl->gl_spin);
1277 handle_callback(gl, state, delay, true);
1278 spin_unlock(&gl->gl_spin);
1279 if (queue_delayed_work(glock_workqueue, &gl->gl_work, delay) == 0)
1280 gfs2_glock_put(gl);
1281 }
1282
1283 /**
1284 * gfs2_should_freeze - Figure out if glock should be frozen
1285 * @gl: The glock in question
1286 *
1287 * Glocks are not frozen if (a) the result of the dlm operation is
1288 * an error, (b) the locking operation was an unlock operation or
1289 * (c) if there is a "noexp" flagged request anywhere in the queue
1290 *
1291 * Returns: 1 if freezing should occur, 0 otherwise
1292 */
1293
1294 static int gfs2_should_freeze(const struct gfs2_glock *gl)
1295 {
1296 const struct gfs2_holder *gh;
1297
1298 if (gl->gl_reply & ~LM_OUT_ST_MASK)
1299 return 0;
1300 if (gl->gl_target == LM_ST_UNLOCKED)
1301 return 0;
1302
1303 list_for_each_entry(gh, &gl->gl_holders, gh_list) {
1304 if (test_bit(HIF_HOLDER, &gh->gh_iflags))
1305 continue;
1306 if (LM_FLAG_NOEXP & gh->gh_flags)
1307 return 0;
1308 }
1309
1310 return 1;
1311 }
1312
1313 /**
1314 * gfs2_glock_complete - Callback used by locking
1315 * @gl: Pointer to the glock
1316 * @ret: The return value from the dlm
1317 *
1318 * The gl_reply field is under the gl_spin lock so that it is ok
1319 * to use a bitfield shared with other glock state fields.
1320 */
1321
1322 void gfs2_glock_complete(struct gfs2_glock *gl, int ret)
1323 {
1324 struct lm_lockstruct *ls = &gl->gl_sbd->sd_lockstruct;
1325
1326 spin_lock(&gl->gl_spin);
1327 gl->gl_reply = ret;
1328
1329 if (unlikely(test_bit(DFL_BLOCK_LOCKS, &ls->ls_recover_flags))) {
1330 if (gfs2_should_freeze(gl)) {
1331 set_bit(GLF_FROZEN, &gl->gl_flags);
1332 spin_unlock(&gl->gl_spin);
1333 return;
1334 }
1335 }
1336
1337 gl->gl_lockref.count++;
1338 set_bit(GLF_REPLY_PENDING, &gl->gl_flags);
1339 spin_unlock(&gl->gl_spin);
1340
1341 if (queue_delayed_work(glock_workqueue, &gl->gl_work, 0) == 0)
1342 gfs2_glock_put(gl);
1343 }
1344
1345 static int glock_cmp(void *priv, struct list_head *a, struct list_head *b)
1346 {
1347 struct gfs2_glock *gla, *glb;
1348
1349 gla = list_entry(a, struct gfs2_glock, gl_lru);
1350 glb = list_entry(b, struct gfs2_glock, gl_lru);
1351
1352 if (gla->gl_name.ln_number > glb->gl_name.ln_number)
1353 return 1;
1354 if (gla->gl_name.ln_number < glb->gl_name.ln_number)
1355 return -1;
1356
1357 return 0;
1358 }
1359
1360 /**
1361 * gfs2_dispose_glock_lru - Demote a list of glocks
1362 * @list: The list to dispose of
1363 *
1364 * Disposing of glocks may involve disk accesses, so that here we sort
1365 * the glocks by number (i.e. disk location of the inodes) so that if
1366 * there are any such accesses, they'll be sent in order (mostly).
1367 *
1368 * Must be called under the lru_lock, but may drop and retake this
1369 * lock. While the lru_lock is dropped, entries may vanish from the
1370 * list, but no new entries will appear on the list (since it is
1371 * private)
1372 */
1373
1374 static void gfs2_dispose_glock_lru(struct list_head *list)
1375 __releases(&lru_lock)
1376 __acquires(&lru_lock)
1377 {
1378 struct gfs2_glock *gl;
1379
1380 list_sort(NULL, list, glock_cmp);
1381
1382 while(!list_empty(list)) {
1383 gl = list_entry(list->next, struct gfs2_glock, gl_lru);
1384 list_del_init(&gl->gl_lru);
1385 if (!spin_trylock(&gl->gl_spin)) {
1386 add_back_to_lru:
1387 list_add(&gl->gl_lru, &lru_list);
1388 atomic_inc(&lru_count);
1389 continue;
1390 }
1391 if (test_and_set_bit(GLF_LOCK, &gl->gl_flags)) {
1392 spin_unlock(&gl->gl_spin);
1393 goto add_back_to_lru;
1394 }
1395 clear_bit(GLF_LRU, &gl->gl_flags);
1396 gl->gl_lockref.count++;
1397 if (demote_ok(gl))
1398 handle_callback(gl, LM_ST_UNLOCKED, 0, false);
1399 WARN_ON(!test_and_clear_bit(GLF_LOCK, &gl->gl_flags));
1400 if (queue_delayed_work(glock_workqueue, &gl->gl_work, 0) == 0)
1401 gl->gl_lockref.count--;
1402 spin_unlock(&gl->gl_spin);
1403 cond_resched_lock(&lru_lock);
1404 }
1405 }
1406
1407 /**
1408 * gfs2_scan_glock_lru - Scan the LRU looking for locks to demote
1409 * @nr: The number of entries to scan
1410 *
1411 * This function selects the entries on the LRU which are able to
1412 * be demoted, and then kicks off the process by calling
1413 * gfs2_dispose_glock_lru() above.
1414 */
1415
1416 static long gfs2_scan_glock_lru(int nr)
1417 {
1418 struct gfs2_glock *gl;
1419 LIST_HEAD(skipped);
1420 LIST_HEAD(dispose);
1421 long freed = 0;
1422
1423 spin_lock(&lru_lock);
1424 while ((nr-- >= 0) && !list_empty(&lru_list)) {
1425 gl = list_entry(lru_list.next, struct gfs2_glock, gl_lru);
1426
1427 /* Test for being demotable */
1428 if (!test_bit(GLF_LOCK, &gl->gl_flags)) {
1429 list_move(&gl->gl_lru, &dispose);
1430 atomic_dec(&lru_count);
1431 freed++;
1432 continue;
1433 }
1434
1435 list_move(&gl->gl_lru, &skipped);
1436 }
1437 list_splice(&skipped, &lru_list);
1438 if (!list_empty(&dispose))
1439 gfs2_dispose_glock_lru(&dispose);
1440 spin_unlock(&lru_lock);
1441
1442 return freed;
1443 }
1444
1445 static unsigned long gfs2_glock_shrink_scan(struct shrinker *shrink,
1446 struct shrink_control *sc)
1447 {
1448 if (!(sc->gfp_mask & __GFP_FS))
1449 return SHRINK_STOP;
1450 return gfs2_scan_glock_lru(sc->nr_to_scan);
1451 }
1452
1453 static unsigned long gfs2_glock_shrink_count(struct shrinker *shrink,
1454 struct shrink_control *sc)
1455 {
1456 return vfs_pressure_ratio(atomic_read(&lru_count));
1457 }
1458
1459 static struct shrinker glock_shrinker = {
1460 .seeks = DEFAULT_SEEKS,
1461 .count_objects = gfs2_glock_shrink_count,
1462 .scan_objects = gfs2_glock_shrink_scan,
1463 };
1464
1465 /**
1466 * examine_bucket - Call a function for glock in a hash bucket
1467 * @examiner: the function
1468 * @sdp: the filesystem
1469 * @bucket: the bucket
1470 *
1471 */
1472
1473 static void examine_bucket(glock_examiner examiner, const struct gfs2_sbd *sdp,
1474 unsigned int hash)
1475 {
1476 struct gfs2_glock *gl;
1477 struct hlist_bl_head *head = &gl_hash_table[hash];
1478 struct hlist_bl_node *pos;
1479
1480 rcu_read_lock();
1481 hlist_bl_for_each_entry_rcu(gl, pos, head, gl_list) {
1482 if ((gl->gl_sbd == sdp) && lockref_get_not_dead(&gl->gl_lockref))
1483 examiner(gl);
1484 }
1485 rcu_read_unlock();
1486 cond_resched();
1487 }
1488
1489 static void glock_hash_walk(glock_examiner examiner, const struct gfs2_sbd *sdp)
1490 {
1491 unsigned x;
1492
1493 for (x = 0; x < GFS2_GL_HASH_SIZE; x++)
1494 examine_bucket(examiner, sdp, x);
1495 }
1496
1497
1498 /**
1499 * thaw_glock - thaw out a glock which has an unprocessed reply waiting
1500 * @gl: The glock to thaw
1501 *
1502 */
1503
1504 static void thaw_glock(struct gfs2_glock *gl)
1505 {
1506 if (!test_and_clear_bit(GLF_FROZEN, &gl->gl_flags))
1507 goto out;
1508 set_bit(GLF_REPLY_PENDING, &gl->gl_flags);
1509 if (queue_delayed_work(glock_workqueue, &gl->gl_work, 0) == 0) {
1510 out:
1511 gfs2_glock_put(gl);
1512 }
1513 }
1514
1515 /**
1516 * clear_glock - look at a glock and see if we can free it from glock cache
1517 * @gl: the glock to look at
1518 *
1519 */
1520
1521 static void clear_glock(struct gfs2_glock *gl)
1522 {
1523 gfs2_glock_remove_from_lru(gl);
1524
1525 spin_lock(&gl->gl_spin);
1526 if (gl->gl_state != LM_ST_UNLOCKED)
1527 handle_callback(gl, LM_ST_UNLOCKED, 0, false);
1528 spin_unlock(&gl->gl_spin);
1529 if (queue_delayed_work(glock_workqueue, &gl->gl_work, 0) == 0)
1530 gfs2_glock_put(gl);
1531 }
1532
1533 /**
1534 * gfs2_glock_thaw - Thaw any frozen glocks
1535 * @sdp: The super block
1536 *
1537 */
1538
1539 void gfs2_glock_thaw(struct gfs2_sbd *sdp)
1540 {
1541 glock_hash_walk(thaw_glock, sdp);
1542 }
1543
1544 static void dump_glock(struct seq_file *seq, struct gfs2_glock *gl)
1545 {
1546 spin_lock(&gl->gl_spin);
1547 gfs2_dump_glock(seq, gl);
1548 spin_unlock(&gl->gl_spin);
1549 }
1550
1551 static void dump_glock_func(struct gfs2_glock *gl)
1552 {
1553 dump_glock(NULL, gl);
1554 }
1555
1556 /**
1557 * gfs2_gl_hash_clear - Empty out the glock hash table
1558 * @sdp: the filesystem
1559 * @wait: wait until it's all gone
1560 *
1561 * Called when unmounting the filesystem.
1562 */
1563
1564 void gfs2_gl_hash_clear(struct gfs2_sbd *sdp)
1565 {
1566 set_bit(SDF_SKIP_DLM_UNLOCK, &sdp->sd_flags);
1567 flush_workqueue(glock_workqueue);
1568 glock_hash_walk(clear_glock, sdp);
1569 flush_workqueue(glock_workqueue);
1570 wait_event(sdp->sd_glock_wait, atomic_read(&sdp->sd_glock_disposal) == 0);
1571 glock_hash_walk(dump_glock_func, sdp);
1572 }
1573
1574 void gfs2_glock_finish_truncate(struct gfs2_inode *ip)
1575 {
1576 struct gfs2_glock *gl = ip->i_gl;
1577 int ret;
1578
1579 ret = gfs2_truncatei_resume(ip);
1580 gfs2_assert_withdraw(gl->gl_sbd, ret == 0);
1581
1582 spin_lock(&gl->gl_spin);
1583 clear_bit(GLF_LOCK, &gl->gl_flags);
1584 run_queue(gl, 1);
1585 spin_unlock(&gl->gl_spin);
1586 }
1587
1588 static const char *state2str(unsigned state)
1589 {
1590 switch(state) {
1591 case LM_ST_UNLOCKED:
1592 return "UN";
1593 case LM_ST_SHARED:
1594 return "SH";
1595 case LM_ST_DEFERRED:
1596 return "DF";
1597 case LM_ST_EXCLUSIVE:
1598 return "EX";
1599 }
1600 return "??";
1601 }
1602
1603 static const char *hflags2str(char *buf, unsigned flags, unsigned long iflags)
1604 {
1605 char *p = buf;
1606 if (flags & LM_FLAG_TRY)
1607 *p++ = 't';
1608 if (flags & LM_FLAG_TRY_1CB)
1609 *p++ = 'T';
1610 if (flags & LM_FLAG_NOEXP)
1611 *p++ = 'e';
1612 if (flags & LM_FLAG_ANY)
1613 *p++ = 'A';
1614 if (flags & LM_FLAG_PRIORITY)
1615 *p++ = 'p';
1616 if (flags & GL_ASYNC)
1617 *p++ = 'a';
1618 if (flags & GL_EXACT)
1619 *p++ = 'E';
1620 if (flags & GL_NOCACHE)
1621 *p++ = 'c';
1622 if (test_bit(HIF_HOLDER, &iflags))
1623 *p++ = 'H';
1624 if (test_bit(HIF_WAIT, &iflags))
1625 *p++ = 'W';
1626 if (test_bit(HIF_FIRST, &iflags))
1627 *p++ = 'F';
1628 *p = 0;
1629 return buf;
1630 }
1631
1632 /**
1633 * dump_holder - print information about a glock holder
1634 * @seq: the seq_file struct
1635 * @gh: the glock holder
1636 *
1637 */
1638
1639 static void dump_holder(struct seq_file *seq, const struct gfs2_holder *gh)
1640 {
1641 struct task_struct *gh_owner = NULL;
1642 char flags_buf[32];
1643
1644 rcu_read_lock();
1645 if (gh->gh_owner_pid)
1646 gh_owner = pid_task(gh->gh_owner_pid, PIDTYPE_PID);
1647 gfs2_print_dbg(seq, " H: s:%s f:%s e:%d p:%ld [%s] %pS\n",
1648 state2str(gh->gh_state),
1649 hflags2str(flags_buf, gh->gh_flags, gh->gh_iflags),
1650 gh->gh_error,
1651 gh->gh_owner_pid ? (long)pid_nr(gh->gh_owner_pid) : -1,
1652 gh_owner ? gh_owner->comm : "(ended)",
1653 (void *)gh->gh_ip);
1654 rcu_read_unlock();
1655 }
1656
1657 static const char *gflags2str(char *buf, const struct gfs2_glock *gl)
1658 {
1659 const unsigned long *gflags = &gl->gl_flags;
1660 char *p = buf;
1661
1662 if (test_bit(GLF_LOCK, gflags))
1663 *p++ = 'l';
1664 if (test_bit(GLF_DEMOTE, gflags))
1665 *p++ = 'D';
1666 if (test_bit(GLF_PENDING_DEMOTE, gflags))
1667 *p++ = 'd';
1668 if (test_bit(GLF_DEMOTE_IN_PROGRESS, gflags))
1669 *p++ = 'p';
1670 if (test_bit(GLF_DIRTY, gflags))
1671 *p++ = 'y';
1672 if (test_bit(GLF_LFLUSH, gflags))
1673 *p++ = 'f';
1674 if (test_bit(GLF_INVALIDATE_IN_PROGRESS, gflags))
1675 *p++ = 'i';
1676 if (test_bit(GLF_REPLY_PENDING, gflags))
1677 *p++ = 'r';
1678 if (test_bit(GLF_INITIAL, gflags))
1679 *p++ = 'I';
1680 if (test_bit(GLF_FROZEN, gflags))
1681 *p++ = 'F';
1682 if (test_bit(GLF_QUEUED, gflags))
1683 *p++ = 'q';
1684 if (test_bit(GLF_LRU, gflags))
1685 *p++ = 'L';
1686 if (gl->gl_object)
1687 *p++ = 'o';
1688 if (test_bit(GLF_BLOCKING, gflags))
1689 *p++ = 'b';
1690 *p = 0;
1691 return buf;
1692 }
1693
1694 /**
1695 * gfs2_dump_glock - print information about a glock
1696 * @seq: The seq_file struct
1697 * @gl: the glock
1698 *
1699 * The file format is as follows:
1700 * One line per object, capital letters are used to indicate objects
1701 * G = glock, I = Inode, R = rgrp, H = holder. Glocks are not indented,
1702 * other objects are indented by a single space and follow the glock to
1703 * which they are related. Fields are indicated by lower case letters
1704 * followed by a colon and the field value, except for strings which are in
1705 * [] so that its possible to see if they are composed of spaces for
1706 * example. The field's are n = number (id of the object), f = flags,
1707 * t = type, s = state, r = refcount, e = error, p = pid.
1708 *
1709 */
1710
1711 void gfs2_dump_glock(struct seq_file *seq, const struct gfs2_glock *gl)
1712 {
1713 const struct gfs2_glock_operations *glops = gl->gl_ops;
1714 unsigned long long dtime;
1715 const struct gfs2_holder *gh;
1716 char gflags_buf[32];
1717
1718 dtime = jiffies - gl->gl_demote_time;
1719 dtime *= 1000000/HZ; /* demote time in uSec */
1720 if (!test_bit(GLF_DEMOTE, &gl->gl_flags))
1721 dtime = 0;
1722 gfs2_print_dbg(seq, "G: s:%s n:%u/%llx f:%s t:%s d:%s/%llu a:%d v:%d r:%d m:%ld\n",
1723 state2str(gl->gl_state),
1724 gl->gl_name.ln_type,
1725 (unsigned long long)gl->gl_name.ln_number,
1726 gflags2str(gflags_buf, gl),
1727 state2str(gl->gl_target),
1728 state2str(gl->gl_demote_state), dtime,
1729 atomic_read(&gl->gl_ail_count),
1730 atomic_read(&gl->gl_revokes),
1731 (int)gl->gl_lockref.count, gl->gl_hold_time);
1732
1733 list_for_each_entry(gh, &gl->gl_holders, gh_list)
1734 dump_holder(seq, gh);
1735
1736 if (gl->gl_state != LM_ST_UNLOCKED && glops->go_dump)
1737 glops->go_dump(seq, gl);
1738 }
1739
1740 static int gfs2_glstats_seq_show(struct seq_file *seq, void *iter_ptr)
1741 {
1742 struct gfs2_glock *gl = iter_ptr;
1743
1744 seq_printf(seq, "G: n:%u/%llx rtt:%lld/%lld rttb:%lld/%lld irt:%lld/%lld dcnt: %lld qcnt: %lld\n",
1745 gl->gl_name.ln_type,
1746 (unsigned long long)gl->gl_name.ln_number,
1747 (long long)gl->gl_stats.stats[GFS2_LKS_SRTT],
1748 (long long)gl->gl_stats.stats[GFS2_LKS_SRTTVAR],
1749 (long long)gl->gl_stats.stats[GFS2_LKS_SRTTB],
1750 (long long)gl->gl_stats.stats[GFS2_LKS_SRTTVARB],
1751 (long long)gl->gl_stats.stats[GFS2_LKS_SIRT],
1752 (long long)gl->gl_stats.stats[GFS2_LKS_SIRTVAR],
1753 (long long)gl->gl_stats.stats[GFS2_LKS_DCOUNT],
1754 (long long)gl->gl_stats.stats[GFS2_LKS_QCOUNT]);
1755 return 0;
1756 }
1757
1758 static const char *gfs2_gltype[] = {
1759 "type",
1760 "reserved",
1761 "nondisk",
1762 "inode",
1763 "rgrp",
1764 "meta",
1765 "iopen",
1766 "flock",
1767 "plock",
1768 "quota",
1769 "journal",
1770 };
1771
1772 static const char *gfs2_stype[] = {
1773 [GFS2_LKS_SRTT] = "srtt",
1774 [GFS2_LKS_SRTTVAR] = "srttvar",
1775 [GFS2_LKS_SRTTB] = "srttb",
1776 [GFS2_LKS_SRTTVARB] = "srttvarb",
1777 [GFS2_LKS_SIRT] = "sirt",
1778 [GFS2_LKS_SIRTVAR] = "sirtvar",
1779 [GFS2_LKS_DCOUNT] = "dlm",
1780 [GFS2_LKS_QCOUNT] = "queue",
1781 };
1782
1783 #define GFS2_NR_SBSTATS (ARRAY_SIZE(gfs2_gltype) * ARRAY_SIZE(gfs2_stype))
1784
1785 static int gfs2_sbstats_seq_show(struct seq_file *seq, void *iter_ptr)
1786 {
1787 struct gfs2_glock_iter *gi = seq->private;
1788 struct gfs2_sbd *sdp = gi->sdp;
1789 unsigned index = gi->hash >> 3;
1790 unsigned subindex = gi->hash & 0x07;
1791 s64 value;
1792 int i;
1793
1794 if (index == 0 && subindex != 0)
1795 return 0;
1796
1797 seq_printf(seq, "%-10s %8s:", gfs2_gltype[index],
1798 (index == 0) ? "cpu": gfs2_stype[subindex]);
1799
1800 for_each_possible_cpu(i) {
1801 const struct gfs2_pcpu_lkstats *lkstats = per_cpu_ptr(sdp->sd_lkstats, i);
1802 if (index == 0) {
1803 value = i;
1804 } else {
1805 value = lkstats->lkstats[index - 1].stats[subindex];
1806 }
1807 seq_printf(seq, " %15lld", (long long)value);
1808 }
1809 seq_putc(seq, '\n');
1810 return 0;
1811 }
1812
1813 int __init gfs2_glock_init(void)
1814 {
1815 unsigned i;
1816 for(i = 0; i < GFS2_GL_HASH_SIZE; i++) {
1817 INIT_HLIST_BL_HEAD(&gl_hash_table[i]);
1818 }
1819
1820 glock_workqueue = alloc_workqueue("glock_workqueue", WQ_MEM_RECLAIM |
1821 WQ_HIGHPRI | WQ_FREEZABLE, 0);
1822 if (!glock_workqueue)
1823 return -ENOMEM;
1824 gfs2_delete_workqueue = alloc_workqueue("delete_workqueue",
1825 WQ_MEM_RECLAIM | WQ_FREEZABLE,
1826 0);
1827 if (!gfs2_delete_workqueue) {
1828 destroy_workqueue(glock_workqueue);
1829 return -ENOMEM;
1830 }
1831
1832 register_shrinker(&glock_shrinker);
1833
1834 return 0;
1835 }
1836
1837 void gfs2_glock_exit(void)
1838 {
1839 unregister_shrinker(&glock_shrinker);
1840 destroy_workqueue(glock_workqueue);
1841 destroy_workqueue(gfs2_delete_workqueue);
1842 }
1843
1844 static inline struct gfs2_glock *glock_hash_chain(unsigned hash)
1845 {
1846 return hlist_bl_entry(hlist_bl_first_rcu(&gl_hash_table[hash]),
1847 struct gfs2_glock, gl_list);
1848 }
1849
1850 static inline struct gfs2_glock *glock_hash_next(struct gfs2_glock *gl)
1851 {
1852 return hlist_bl_entry(rcu_dereference(gl->gl_list.next),
1853 struct gfs2_glock, gl_list);
1854 }
1855
1856 static int gfs2_glock_iter_next(struct gfs2_glock_iter *gi)
1857 {
1858 struct gfs2_glock *gl;
1859
1860 do {
1861 gl = gi->gl;
1862 if (gl) {
1863 gi->gl = glock_hash_next(gl);
1864 gi->nhash++;
1865 } else {
1866 if (gi->hash >= GFS2_GL_HASH_SIZE) {
1867 rcu_read_unlock();
1868 return 1;
1869 }
1870 gi->gl = glock_hash_chain(gi->hash);
1871 gi->nhash = 0;
1872 }
1873 while (gi->gl == NULL) {
1874 gi->hash++;
1875 if (gi->hash >= GFS2_GL_HASH_SIZE) {
1876 rcu_read_unlock();
1877 return 1;
1878 }
1879 gi->gl = glock_hash_chain(gi->hash);
1880 gi->nhash = 0;
1881 }
1882 /* Skip entries for other sb and dead entries */
1883 } while (gi->sdp != gi->gl->gl_sbd ||
1884 __lockref_is_dead(&gi->gl->gl_lockref));
1885
1886 return 0;
1887 }
1888
1889 static void *gfs2_glock_seq_start(struct seq_file *seq, loff_t *pos)
1890 {
1891 struct gfs2_glock_iter *gi = seq->private;
1892 loff_t n = *pos;
1893
1894 if (gi->last_pos <= *pos)
1895 n = gi->nhash + (*pos - gi->last_pos);
1896 else
1897 gi->hash = 0;
1898
1899 gi->nhash = 0;
1900 rcu_read_lock();
1901
1902 do {
1903 if (gfs2_glock_iter_next(gi))
1904 return NULL;
1905 } while (n--);
1906
1907 gi->last_pos = *pos;
1908 return gi->gl;
1909 }
1910
1911 static void *gfs2_glock_seq_next(struct seq_file *seq, void *iter_ptr,
1912 loff_t *pos)
1913 {
1914 struct gfs2_glock_iter *gi = seq->private;
1915
1916 (*pos)++;
1917 gi->last_pos = *pos;
1918 if (gfs2_glock_iter_next(gi))
1919 return NULL;
1920
1921 return gi->gl;
1922 }
1923
1924 static void gfs2_glock_seq_stop(struct seq_file *seq, void *iter_ptr)
1925 {
1926 struct gfs2_glock_iter *gi = seq->private;
1927
1928 if (gi->gl)
1929 rcu_read_unlock();
1930 gi->gl = NULL;
1931 }
1932
1933 static int gfs2_glock_seq_show(struct seq_file *seq, void *iter_ptr)
1934 {
1935 dump_glock(seq, iter_ptr);
1936 return 0;
1937 }
1938
1939 static void *gfs2_sbstats_seq_start(struct seq_file *seq, loff_t *pos)
1940 {
1941 struct gfs2_glock_iter *gi = seq->private;
1942
1943 gi->hash = *pos;
1944 if (*pos >= GFS2_NR_SBSTATS)
1945 return NULL;
1946 preempt_disable();
1947 return SEQ_START_TOKEN;
1948 }
1949
1950 static void *gfs2_sbstats_seq_next(struct seq_file *seq, void *iter_ptr,
1951 loff_t *pos)
1952 {
1953 struct gfs2_glock_iter *gi = seq->private;
1954 (*pos)++;
1955 gi->hash++;
1956 if (gi->hash >= GFS2_NR_SBSTATS) {
1957 preempt_enable();
1958 return NULL;
1959 }
1960 return SEQ_START_TOKEN;
1961 }
1962
1963 static void gfs2_sbstats_seq_stop(struct seq_file *seq, void *iter_ptr)
1964 {
1965 preempt_enable();
1966 }
1967
1968 static const struct seq_operations gfs2_glock_seq_ops = {
1969 .start = gfs2_glock_seq_start,
1970 .next = gfs2_glock_seq_next,
1971 .stop = gfs2_glock_seq_stop,
1972 .show = gfs2_glock_seq_show,
1973 };
1974
1975 static const struct seq_operations gfs2_glstats_seq_ops = {
1976 .start = gfs2_glock_seq_start,
1977 .next = gfs2_glock_seq_next,
1978 .stop = gfs2_glock_seq_stop,
1979 .show = gfs2_glstats_seq_show,
1980 };
1981
1982 static const struct seq_operations gfs2_sbstats_seq_ops = {
1983 .start = gfs2_sbstats_seq_start,
1984 .next = gfs2_sbstats_seq_next,
1985 .stop = gfs2_sbstats_seq_stop,
1986 .show = gfs2_sbstats_seq_show,
1987 };
1988
1989 #define GFS2_SEQ_GOODSIZE min(PAGE_SIZE << PAGE_ALLOC_COSTLY_ORDER, 65536UL)
1990
1991 static int gfs2_glocks_open(struct inode *inode, struct file *file)
1992 {
1993 int ret = seq_open_private(file, &gfs2_glock_seq_ops,
1994 sizeof(struct gfs2_glock_iter));
1995 if (ret == 0) {
1996 struct seq_file *seq = file->private_data;
1997 struct gfs2_glock_iter *gi = seq->private;
1998 gi->sdp = inode->i_private;
1999 seq->buf = kmalloc(GFS2_SEQ_GOODSIZE, GFP_KERNEL | __GFP_NOWARN);
2000 if (seq->buf)
2001 seq->size = GFS2_SEQ_GOODSIZE;
2002 }
2003 return ret;
2004 }
2005
2006 static int gfs2_glstats_open(struct inode *inode, struct file *file)
2007 {
2008 int ret = seq_open_private(file, &gfs2_glstats_seq_ops,
2009 sizeof(struct gfs2_glock_iter));
2010 if (ret == 0) {
2011 struct seq_file *seq = file->private_data;
2012 struct gfs2_glock_iter *gi = seq->private;
2013 gi->sdp = inode->i_private;
2014 seq->buf = kmalloc(GFS2_SEQ_GOODSIZE, GFP_KERNEL | __GFP_NOWARN);
2015 if (seq->buf)
2016 seq->size = GFS2_SEQ_GOODSIZE;
2017 }
2018 return ret;
2019 }
2020
2021 static int gfs2_sbstats_open(struct inode *inode, struct file *file)
2022 {
2023 int ret = seq_open_private(file, &gfs2_sbstats_seq_ops,
2024 sizeof(struct gfs2_glock_iter));
2025 if (ret == 0) {
2026 struct seq_file *seq = file->private_data;
2027 struct gfs2_glock_iter *gi = seq->private;
2028 gi->sdp = inode->i_private;
2029 }
2030 return ret;
2031 }
2032
2033 static const struct file_operations gfs2_glocks_fops = {
2034 .owner = THIS_MODULE,
2035 .open = gfs2_glocks_open,
2036 .read = seq_read,
2037 .llseek = seq_lseek,
2038 .release = seq_release_private,
2039 };
2040
2041 static const struct file_operations gfs2_glstats_fops = {
2042 .owner = THIS_MODULE,
2043 .open = gfs2_glstats_open,
2044 .read = seq_read,
2045 .llseek = seq_lseek,
2046 .release = seq_release_private,
2047 };
2048
2049 static const struct file_operations gfs2_sbstats_fops = {
2050 .owner = THIS_MODULE,
2051 .open = gfs2_sbstats_open,
2052 .read = seq_read,
2053 .llseek = seq_lseek,
2054 .release = seq_release_private,
2055 };
2056
2057 int gfs2_create_debugfs_file(struct gfs2_sbd *sdp)
2058 {
2059 sdp->debugfs_dir = debugfs_create_dir(sdp->sd_table_name, gfs2_root);
2060 if (!sdp->debugfs_dir)
2061 return -ENOMEM;
2062 sdp->debugfs_dentry_glocks = debugfs_create_file("glocks",
2063 S_IFREG | S_IRUGO,
2064 sdp->debugfs_dir, sdp,
2065 &gfs2_glocks_fops);
2066 if (!sdp->debugfs_dentry_glocks)
2067 goto fail;
2068
2069 sdp->debugfs_dentry_glstats = debugfs_create_file("glstats",
2070 S_IFREG | S_IRUGO,
2071 sdp->debugfs_dir, sdp,
2072 &gfs2_glstats_fops);
2073 if (!sdp->debugfs_dentry_glstats)
2074 goto fail;
2075
2076 sdp->debugfs_dentry_sbstats = debugfs_create_file("sbstats",
2077 S_IFREG | S_IRUGO,
2078 sdp->debugfs_dir, sdp,
2079 &gfs2_sbstats_fops);
2080 if (!sdp->debugfs_dentry_sbstats)
2081 goto fail;
2082
2083 return 0;
2084 fail:
2085 gfs2_delete_debugfs_file(sdp);
2086 return -ENOMEM;
2087 }
2088
2089 void gfs2_delete_debugfs_file(struct gfs2_sbd *sdp)
2090 {
2091 if (sdp->debugfs_dir) {
2092 if (sdp->debugfs_dentry_glocks) {
2093 debugfs_remove(sdp->debugfs_dentry_glocks);
2094 sdp->debugfs_dentry_glocks = NULL;
2095 }
2096 if (sdp->debugfs_dentry_glstats) {
2097 debugfs_remove(sdp->debugfs_dentry_glstats);
2098 sdp->debugfs_dentry_glstats = NULL;
2099 }
2100 if (sdp->debugfs_dentry_sbstats) {
2101 debugfs_remove(sdp->debugfs_dentry_sbstats);
2102 sdp->debugfs_dentry_sbstats = NULL;
2103 }
2104 debugfs_remove(sdp->debugfs_dir);
2105 sdp->debugfs_dir = NULL;
2106 }
2107 }
2108
2109 int gfs2_register_debugfs(void)
2110 {
2111 gfs2_root = debugfs_create_dir("gfs2", NULL);
2112 return gfs2_root ? 0 : -ENOMEM;
2113 }
2114
2115 void gfs2_unregister_debugfs(void)
2116 {
2117 debugfs_remove(gfs2_root);
2118 gfs2_root = NULL;
2119 }
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