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Merge branch 'for-3.11/drivers' of git://git.kernel.dk/linux-block
[linux-2.6.git] / fs / gfs2 / glock.c
blob9435384562a271cacd5219651269b36d5d2923c4
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 #include <linux/percpu.h>
33 #include <linux/list_sort.h>
34
35 #include "gfs2.h"
36 #include "incore.h"
37 #include "glock.h"
38 #include "glops.h"
39 #include "inode.h"
40 #include "lops.h"
41 #include "meta_io.h"
42 #include "quota.h"
43 #include "super.h"
44 #include "util.h"
45 #include "bmap.h"
46 #define CREATE_TRACE_POINTS
47 #include "trace_gfs2.h"
48
49 struct gfs2_glock_iter {
50 int hash; /* hash bucket index */
51 unsigned nhash; /* Index within current bucket */
52 struct gfs2_sbd *sdp; /* incore superblock */
53 struct gfs2_glock *gl; /* current glock struct */
54 loff_t last_pos; /* last position */
55 };
56
57 typedef void (*glock_examiner) (struct gfs2_glock * gl);
58
59 static void do_xmote(struct gfs2_glock *gl, struct gfs2_holder *gh, unsigned int target);
60
61 static struct dentry *gfs2_root;
62 static struct workqueue_struct *glock_workqueue;
63 struct workqueue_struct *gfs2_delete_workqueue;
64 static LIST_HEAD(lru_list);
65 static atomic_t lru_count = ATOMIC_INIT(0);
66 static DEFINE_SPINLOCK(lru_lock);
67
68 #define GFS2_GL_HASH_SHIFT 15
69 #define GFS2_GL_HASH_SIZE (1 << GFS2_GL_HASH_SHIFT)
70 #define GFS2_GL_HASH_MASK (GFS2_GL_HASH_SIZE - 1)
71
72 static struct hlist_bl_head gl_hash_table[GFS2_GL_HASH_SIZE];
73 static struct dentry *gfs2_root;
74
75 /**
76 * gl_hash() - Turn glock number into hash bucket number
77 * @lock: The glock number
78 *
79 * Returns: The number of the corresponding hash bucket
80 */
81
82 static unsigned int gl_hash(const struct gfs2_sbd *sdp,
83 const struct lm_lockname *name)
84 {
85 unsigned int h;
86
87 h = jhash(&name->ln_number, sizeof(u64), 0);
88 h = jhash(&name->ln_type, sizeof(unsigned int), h);
89 h = jhash(&sdp, sizeof(struct gfs2_sbd *), h);
90 h &= GFS2_GL_HASH_MASK;
91
92 return h;
93 }
94
95 static inline void spin_lock_bucket(unsigned int hash)
96 {
97 hlist_bl_lock(&gl_hash_table[hash]);
98 }
99
100 static inline void spin_unlock_bucket(unsigned int hash)
101 {
102 hlist_bl_unlock(&gl_hash_table[hash]);
103 }
104
105 static void gfs2_glock_dealloc(struct rcu_head *rcu)
106 {
107 struct gfs2_glock *gl = container_of(rcu, struct gfs2_glock, gl_rcu);
108
109 if (gl->gl_ops->go_flags & GLOF_ASPACE) {
110 kmem_cache_free(gfs2_glock_aspace_cachep, gl);
111 } else {
112 kfree(gl->gl_lksb.sb_lvbptr);
113 kmem_cache_free(gfs2_glock_cachep, gl);
114 }
115 }
116
117 void gfs2_glock_free(struct gfs2_glock *gl)
118 {
119 struct gfs2_sbd *sdp = gl->gl_sbd;
120
121 call_rcu(&gl->gl_rcu, gfs2_glock_dealloc);
122 if (atomic_dec_and_test(&sdp->sd_glock_disposal))
123 wake_up(&sdp->sd_glock_wait);
124 }
125
126 /**
127 * gfs2_glock_hold() - increment reference count on glock
128 * @gl: The glock to hold
129 *
130 */
131
132 void gfs2_glock_hold(struct gfs2_glock *gl)
133 {
134 GLOCK_BUG_ON(gl, atomic_read(&gl->gl_ref) == 0);
135 atomic_inc(&gl->gl_ref);
136 }
137
138 /**
139 * demote_ok - Check to see if it's ok to unlock a glock
140 * @gl: the glock
141 *
142 * Returns: 1 if it's ok
143 */
144
145 static int demote_ok(const struct gfs2_glock *gl)
146 {
147 const struct gfs2_glock_operations *glops = gl->gl_ops;
148
149 if (gl->gl_state == LM_ST_UNLOCKED)
150 return 0;
151 if (!list_empty(&gl->gl_holders))
152 return 0;
153 if (glops->go_demote_ok)
154 return glops->go_demote_ok(gl);
155 return 1;
156 }
157
158
159 void gfs2_glock_add_to_lru(struct gfs2_glock *gl)
160 {
161 spin_lock(&lru_lock);
162
163 if (!list_empty(&gl->gl_lru))
164 list_del_init(&gl->gl_lru);
165 else
166 atomic_inc(&lru_count);
167
168 list_add_tail(&gl->gl_lru, &lru_list);
169 set_bit(GLF_LRU, &gl->gl_flags);
170 spin_unlock(&lru_lock);
171 }
172
173 static void __gfs2_glock_remove_from_lru(struct gfs2_glock *gl)
174 {
175 if (!list_empty(&gl->gl_lru)) {
176 list_del_init(&gl->gl_lru);
177 atomic_dec(&lru_count);
178 clear_bit(GLF_LRU, &gl->gl_flags);
179 }
180 }
181
182 static void gfs2_glock_remove_from_lru(struct gfs2_glock *gl)
183 {
184 spin_lock(&lru_lock);
185 __gfs2_glock_remove_from_lru(gl);
186 spin_unlock(&lru_lock);
187 }
188
189 /**
190 * gfs2_glock_put_nolock() - Decrement reference count on glock
191 * @gl: The glock to put
192 *
193 * This function should only be used if the caller has its own reference
194 * to the glock, in addition to the one it is dropping.
195 */
196
197 void gfs2_glock_put_nolock(struct gfs2_glock *gl)
198 {
199 if (atomic_dec_and_test(&gl->gl_ref))
200 GLOCK_BUG_ON(gl, 1);
201 }
202
203 /**
204 * gfs2_glock_put() - Decrement reference count on glock
205 * @gl: The glock to put
206 *
207 */
208
209 void gfs2_glock_put(struct gfs2_glock *gl)
210 {
211 struct gfs2_sbd *sdp = gl->gl_sbd;
212 struct address_space *mapping = gfs2_glock2aspace(gl);
213
214 if (atomic_dec_and_lock(&gl->gl_ref, &lru_lock)) {
215 __gfs2_glock_remove_from_lru(gl);
216 spin_unlock(&lru_lock);
217 spin_lock_bucket(gl->gl_hash);
218 hlist_bl_del_rcu(&gl->gl_list);
219 spin_unlock_bucket(gl->gl_hash);
220 GLOCK_BUG_ON(gl, !list_empty(&gl->gl_holders));
221 GLOCK_BUG_ON(gl, mapping && mapping->nrpages);
222 trace_gfs2_glock_put(gl);
223 sdp->sd_lockstruct.ls_ops->lm_put_lock(gl);
224 }
225 }
226
227 /**
228 * search_bucket() - Find struct gfs2_glock by lock number
229 * @bucket: the bucket to search
230 * @name: The lock name
231 *
232 * Returns: NULL, or the struct gfs2_glock with the requested number
233 */
234
235 static struct gfs2_glock *search_bucket(unsigned int hash,
236 const struct gfs2_sbd *sdp,
237 const struct lm_lockname *name)
238 {
239 struct gfs2_glock *gl;
240 struct hlist_bl_node *h;
241
242 hlist_bl_for_each_entry_rcu(gl, h, &gl_hash_table[hash], gl_list) {
243 if (!lm_name_equal(&gl->gl_name, name))
244 continue;
245 if (gl->gl_sbd != sdp)
246 continue;
247 if (atomic_inc_not_zero(&gl->gl_ref))
248 return gl;
249 }
250
251 return NULL;
252 }
253
254 /**
255 * may_grant - check if its ok to grant a new lock
256 * @gl: The glock
257 * @gh: The lock request which we wish to grant
258 *
259 * Returns: true if its ok to grant the lock
260 */
261
262 static inline int may_grant(const struct gfs2_glock *gl, const struct gfs2_holder *gh)
263 {
264 const struct gfs2_holder *gh_head = list_entry(gl->gl_holders.next, const struct gfs2_holder, gh_list);
265 if ((gh->gh_state == LM_ST_EXCLUSIVE ||
266 gh_head->gh_state == LM_ST_EXCLUSIVE) && gh != gh_head)
267 return 0;
268 if (gl->gl_state == gh->gh_state)
269 return 1;
270 if (gh->gh_flags & GL_EXACT)
271 return 0;
272 if (gl->gl_state == LM_ST_EXCLUSIVE) {
273 if (gh->gh_state == LM_ST_SHARED && gh_head->gh_state == LM_ST_SHARED)
274 return 1;
275 if (gh->gh_state == LM_ST_DEFERRED && gh_head->gh_state == LM_ST_DEFERRED)
276 return 1;
277 }
278 if (gl->gl_state != LM_ST_UNLOCKED && (gh->gh_flags & LM_FLAG_ANY))
279 return 1;
280 return 0;
281 }
282
283 static void gfs2_holder_wake(struct gfs2_holder *gh)
284 {
285 clear_bit(HIF_WAIT, &gh->gh_iflags);
286 smp_mb__after_clear_bit();
287 wake_up_bit(&gh->gh_iflags, HIF_WAIT);
288 }
289
290 /**
291 * do_error - Something unexpected has happened during a lock request
292 *
293 */
294
295 static inline void do_error(struct gfs2_glock *gl, const int ret)
296 {
297 struct gfs2_holder *gh, *tmp;
298
299 list_for_each_entry_safe(gh, tmp, &gl->gl_holders, gh_list) {
300 if (test_bit(HIF_HOLDER, &gh->gh_iflags))
301 continue;
302 if (ret & LM_OUT_ERROR)
303 gh->gh_error = -EIO;
304 else if (gh->gh_flags & (LM_FLAG_TRY | LM_FLAG_TRY_1CB))
305 gh->gh_error = GLR_TRYFAILED;
306 else
307 continue;
308 list_del_init(&gh->gh_list);
309 trace_gfs2_glock_queue(gh, 0);
310 gfs2_holder_wake(gh);
311 }
312 }
313
314 /**
315 * do_promote - promote as many requests as possible on the current queue
316 * @gl: The glock
317 *
318 * Returns: 1 if there is a blocked holder at the head of the list, or 2
319 * if a type specific operation is underway.
320 */
321
322 static int do_promote(struct gfs2_glock *gl)
323 __releases(&gl->gl_spin)
324 __acquires(&gl->gl_spin)
325 {
326 const struct gfs2_glock_operations *glops = gl->gl_ops;
327 struct gfs2_holder *gh, *tmp;
328 int ret;
329
330 restart:
331 list_for_each_entry_safe(gh, tmp, &gl->gl_holders, gh_list) {
332 if (test_bit(HIF_HOLDER, &gh->gh_iflags))
333 continue;
334 if (may_grant(gl, gh)) {
335 if (gh->gh_list.prev == &gl->gl_holders &&
336 glops->go_lock) {
337 spin_unlock(&gl->gl_spin);
338 /* FIXME: eliminate this eventually */
339 ret = glops->go_lock(gh);
340 spin_lock(&gl->gl_spin);
341 if (ret) {
342 if (ret == 1)
343 return 2;
344 gh->gh_error = ret;
345 list_del_init(&gh->gh_list);
346 trace_gfs2_glock_queue(gh, 0);
347 gfs2_holder_wake(gh);
348 goto restart;
349 }
350 set_bit(HIF_HOLDER, &gh->gh_iflags);
351 trace_gfs2_promote(gh, 1);
352 gfs2_holder_wake(gh);
353 goto restart;
354 }
355 set_bit(HIF_HOLDER, &gh->gh_iflags);
356 trace_gfs2_promote(gh, 0);
357 gfs2_holder_wake(gh);
358 continue;
359 }
360 if (gh->gh_list.prev == &gl->gl_holders)
361 return 1;
362 do_error(gl, 0);
363 break;
364 }
365 return 0;
366 }
367
368 /**
369 * find_first_waiter - find the first gh that's waiting for the glock
370 * @gl: the glock
371 */
372
373 static inline struct gfs2_holder *find_first_waiter(const struct gfs2_glock *gl)
374 {
375 struct gfs2_holder *gh;
376
377 list_for_each_entry(gh, &gl->gl_holders, gh_list) {
378 if (!test_bit(HIF_HOLDER, &gh->gh_iflags))
379 return gh;
380 }
381 return NULL;
382 }
383
384 /**
385 * state_change - record that the glock is now in a different state
386 * @gl: the glock
387 * @new_state the new state
388 *
389 */
390
391 static void state_change(struct gfs2_glock *gl, unsigned int new_state)
392 {
393 int held1, held2;
394
395 held1 = (gl->gl_state != LM_ST_UNLOCKED);
396 held2 = (new_state != LM_ST_UNLOCKED);
397
398 if (held1 != held2) {
399 if (held2)
400 gfs2_glock_hold(gl);
401 else
402 gfs2_glock_put_nolock(gl);
403 }
404 if (held1 && held2 && list_empty(&gl->gl_holders))
405 clear_bit(GLF_QUEUED, &gl->gl_flags);
406
407 if (new_state != gl->gl_target)
408 /* shorten our minimum hold time */
409 gl->gl_hold_time = max(gl->gl_hold_time - GL_GLOCK_HOLD_DECR,
410 GL_GLOCK_MIN_HOLD);
411 gl->gl_state = new_state;
412 gl->gl_tchange = jiffies;
413 }
414
415 static void gfs2_demote_wake(struct gfs2_glock *gl)
416 {
417 gl->gl_demote_state = LM_ST_EXCLUSIVE;
418 clear_bit(GLF_DEMOTE, &gl->gl_flags);
419 smp_mb__after_clear_bit();
420 wake_up_bit(&gl->gl_flags, GLF_DEMOTE);
421 }
422
423 /**
424 * finish_xmote - The DLM has replied to one of our lock requests
425 * @gl: The glock
426 * @ret: The status from the DLM
427 *
428 */
429
430 static void finish_xmote(struct gfs2_glock *gl, unsigned int ret)
431 {
432 const struct gfs2_glock_operations *glops = gl->gl_ops;
433 struct gfs2_holder *gh;
434 unsigned state = ret & LM_OUT_ST_MASK;
435 int rv;
436
437 spin_lock(&gl->gl_spin);
438 trace_gfs2_glock_state_change(gl, state);
439 state_change(gl, state);
440 gh = find_first_waiter(gl);
441
442 /* Demote to UN request arrived during demote to SH or DF */
443 if (test_bit(GLF_DEMOTE_IN_PROGRESS, &gl->gl_flags) &&
444 state != LM_ST_UNLOCKED && gl->gl_demote_state == LM_ST_UNLOCKED)
445 gl->gl_target = LM_ST_UNLOCKED;
446
447 /* Check for state != intended state */
448 if (unlikely(state != gl->gl_target)) {
449 if (gh && !test_bit(GLF_DEMOTE_IN_PROGRESS, &gl->gl_flags)) {
450 /* move to back of queue and try next entry */
451 if (ret & LM_OUT_CANCELED) {
452 if ((gh->gh_flags & LM_FLAG_PRIORITY) == 0)
453 list_move_tail(&gh->gh_list, &gl->gl_holders);
454 gh = find_first_waiter(gl);
455 gl->gl_target = gh->gh_state;
456 goto retry;
457 }
458 /* Some error or failed "try lock" - report it */
459 if ((ret & LM_OUT_ERROR) ||
460 (gh->gh_flags & (LM_FLAG_TRY | LM_FLAG_TRY_1CB))) {
461 gl->gl_target = gl->gl_state;
462 do_error(gl, ret);
463 goto out;
464 }
465 }
466 switch(state) {
467 /* Unlocked due to conversion deadlock, try again */
468 case LM_ST_UNLOCKED:
469 retry:
470 do_xmote(gl, gh, gl->gl_target);
471 break;
472 /* Conversion fails, unlock and try again */
473 case LM_ST_SHARED:
474 case LM_ST_DEFERRED:
475 do_xmote(gl, gh, LM_ST_UNLOCKED);
476 break;
477 default: /* Everything else */
478 printk(KERN_ERR "GFS2: wanted %u got %u\n", gl->gl_target, state);
479 GLOCK_BUG_ON(gl, 1);
480 }
481 spin_unlock(&gl->gl_spin);
482 return;
483 }
484
485 /* Fast path - we got what we asked for */
486 if (test_and_clear_bit(GLF_DEMOTE_IN_PROGRESS, &gl->gl_flags))
487 gfs2_demote_wake(gl);
488 if (state != LM_ST_UNLOCKED) {
489 if (glops->go_xmote_bh) {
490 spin_unlock(&gl->gl_spin);
491 rv = glops->go_xmote_bh(gl, gh);
492 spin_lock(&gl->gl_spin);
493 if (rv) {
494 do_error(gl, rv);
495 goto out;
496 }
497 }
498 rv = do_promote(gl);
499 if (rv == 2)
500 goto out_locked;
501 }
502 out:
503 clear_bit(GLF_LOCK, &gl->gl_flags);
504 out_locked:
505 spin_unlock(&gl->gl_spin);
506 }
507
508 /**
509 * do_xmote - Calls the DLM to change the state of a lock
510 * @gl: The lock state
511 * @gh: The holder (only for promotes)
512 * @target: The target lock state
513 *
514 */
515
516 static void do_xmote(struct gfs2_glock *gl, struct gfs2_holder *gh, unsigned int target)
517 __releases(&gl->gl_spin)
518 __acquires(&gl->gl_spin)
519 {
520 const struct gfs2_glock_operations *glops = gl->gl_ops;
521 struct gfs2_sbd *sdp = gl->gl_sbd;
522 unsigned int lck_flags = gh ? gh->gh_flags : 0;
523 int ret;
524
525 lck_flags &= (LM_FLAG_TRY | LM_FLAG_TRY_1CB | LM_FLAG_NOEXP |
526 LM_FLAG_PRIORITY);
527 GLOCK_BUG_ON(gl, gl->gl_state == target);
528 GLOCK_BUG_ON(gl, gl->gl_state == gl->gl_target);
529 if ((target == LM_ST_UNLOCKED || target == LM_ST_DEFERRED) &&
530 glops->go_inval) {
531 set_bit(GLF_INVALIDATE_IN_PROGRESS, &gl->gl_flags);
532 do_error(gl, 0); /* Fail queued try locks */
533 }
534 gl->gl_req = target;
535 set_bit(GLF_BLOCKING, &gl->gl_flags);
536 if ((gl->gl_req == LM_ST_UNLOCKED) ||
537 (gl->gl_state == LM_ST_EXCLUSIVE) ||
538 (lck_flags & (LM_FLAG_TRY|LM_FLAG_TRY_1CB)))
539 clear_bit(GLF_BLOCKING, &gl->gl_flags);
540 spin_unlock(&gl->gl_spin);
541 if (glops->go_sync)
542 glops->go_sync(gl);
543 if (test_bit(GLF_INVALIDATE_IN_PROGRESS, &gl->gl_flags))
544 glops->go_inval(gl, target == LM_ST_DEFERRED ? 0 : DIO_METADATA);
545 clear_bit(GLF_INVALIDATE_IN_PROGRESS, &gl->gl_flags);
546
547 gfs2_glock_hold(gl);
548 if (sdp->sd_lockstruct.ls_ops->lm_lock) {
549 /* lock_dlm */
550 ret = sdp->sd_lockstruct.ls_ops->lm_lock(gl, target, lck_flags);
551 if (ret) {
552 printk(KERN_ERR "GFS2: lm_lock ret %d\n", ret);
553 GLOCK_BUG_ON(gl, 1);
554 }
555 } else { /* lock_nolock */
556 finish_xmote(gl, target);
557 if (queue_delayed_work(glock_workqueue, &gl->gl_work, 0) == 0)
558 gfs2_glock_put(gl);
559 }
560
561 spin_lock(&gl->gl_spin);
562 }
563
564 /**
565 * find_first_holder - find the first "holder" gh
566 * @gl: the glock
567 */
568
569 static inline struct gfs2_holder *find_first_holder(const struct gfs2_glock *gl)
570 {
571 struct gfs2_holder *gh;
572
573 if (!list_empty(&gl->gl_holders)) {
574 gh = list_entry(gl->gl_holders.next, struct gfs2_holder, gh_list);
575 if (test_bit(HIF_HOLDER, &gh->gh_iflags))
576 return gh;
577 }
578 return NULL;
579 }
580
581 /**
582 * run_queue - do all outstanding tasks related to a glock
583 * @gl: The glock in question
584 * @nonblock: True if we must not block in run_queue
585 *
586 */
587
588 static void run_queue(struct gfs2_glock *gl, const int nonblock)
589 __releases(&gl->gl_spin)
590 __acquires(&gl->gl_spin)
591 {
592 struct gfs2_holder *gh = NULL;
593 int ret;
594
595 if (test_and_set_bit(GLF_LOCK, &gl->gl_flags))
596 return;
597
598 GLOCK_BUG_ON(gl, test_bit(GLF_DEMOTE_IN_PROGRESS, &gl->gl_flags));
599
600 if (test_bit(GLF_DEMOTE, &gl->gl_flags) &&
601 gl->gl_demote_state != gl->gl_state) {
602 if (find_first_holder(gl))
603 goto out_unlock;
604 if (nonblock)
605 goto out_sched;
606 set_bit(GLF_DEMOTE_IN_PROGRESS, &gl->gl_flags);
607 GLOCK_BUG_ON(gl, gl->gl_demote_state == LM_ST_EXCLUSIVE);
608 gl->gl_target = gl->gl_demote_state;
609 } else {
610 if (test_bit(GLF_DEMOTE, &gl->gl_flags))
611 gfs2_demote_wake(gl);
612 ret = do_promote(gl);
613 if (ret == 0)
614 goto out_unlock;
615 if (ret == 2)
616 goto out;
617 gh = find_first_waiter(gl);
618 gl->gl_target = gh->gh_state;
619 if (!(gh->gh_flags & (LM_FLAG_TRY | LM_FLAG_TRY_1CB)))
620 do_error(gl, 0); /* Fail queued try locks */
621 }
622 do_xmote(gl, gh, gl->gl_target);
623 out:
624 return;
625
626 out_sched:
627 clear_bit(GLF_LOCK, &gl->gl_flags);
628 smp_mb__after_clear_bit();
629 gfs2_glock_hold(gl);
630 if (queue_delayed_work(glock_workqueue, &gl->gl_work, 0) == 0)
631 gfs2_glock_put_nolock(gl);
632 return;
633
634 out_unlock:
635 clear_bit(GLF_LOCK, &gl->gl_flags);
636 smp_mb__after_clear_bit();
637 return;
638 }
639
640 static void delete_work_func(struct work_struct *work)
641 {
642 struct gfs2_glock *gl = container_of(work, struct gfs2_glock, gl_delete);
643 struct gfs2_sbd *sdp = gl->gl_sbd;
644 struct gfs2_inode *ip;
645 struct inode *inode;
646 u64 no_addr = gl->gl_name.ln_number;
647
648 ip = gl->gl_object;
649 /* Note: Unsafe to dereference ip as we don't hold right refs/locks */
650
651 if (ip)
652 inode = gfs2_ilookup(sdp->sd_vfs, no_addr, 1);
653 else
654 inode = gfs2_lookup_by_inum(sdp, no_addr, NULL, GFS2_BLKST_UNLINKED);
655 if (inode && !IS_ERR(inode)) {
656 d_prune_aliases(inode);
657 iput(inode);
658 }
659 gfs2_glock_put(gl);
660 }
661
662 static void glock_work_func(struct work_struct *work)
663 {
664 unsigned long delay = 0;
665 struct gfs2_glock *gl = container_of(work, struct gfs2_glock, gl_work.work);
666 int drop_ref = 0;
667
668 if (test_and_clear_bit(GLF_REPLY_PENDING, &gl->gl_flags)) {
669 finish_xmote(gl, gl->gl_reply);
670 drop_ref = 1;
671 }
672 spin_lock(&gl->gl_spin);
673 if (test_bit(GLF_PENDING_DEMOTE, &gl->gl_flags) &&
674 gl->gl_state != LM_ST_UNLOCKED &&
675 gl->gl_demote_state != LM_ST_EXCLUSIVE) {
676 unsigned long holdtime, now = jiffies;
677
678 holdtime = gl->gl_tchange + gl->gl_hold_time;
679 if (time_before(now, holdtime))
680 delay = holdtime - now;
681
682 if (!delay) {
683 clear_bit(GLF_PENDING_DEMOTE, &gl->gl_flags);
684 set_bit(GLF_DEMOTE, &gl->gl_flags);
685 }
686 }
687 run_queue(gl, 0);
688 spin_unlock(&gl->gl_spin);
689 if (!delay)
690 gfs2_glock_put(gl);
691 else {
692 if (gl->gl_name.ln_type != LM_TYPE_INODE)
693 delay = 0;
694 if (queue_delayed_work(glock_workqueue, &gl->gl_work, delay) == 0)
695 gfs2_glock_put(gl);
696 }
697 if (drop_ref)
698 gfs2_glock_put(gl);
699 }
700
701 /**
702 * gfs2_glock_get() - Get a glock, or create one if one doesn't exist
703 * @sdp: The GFS2 superblock
704 * @number: the lock number
705 * @glops: The glock_operations to use
706 * @create: If 0, don't create the glock if it doesn't exist
707 * @glp: the glock is returned here
708 *
709 * This does not lock a glock, just finds/creates structures for one.
710 *
711 * Returns: errno
712 */
713
714 int gfs2_glock_get(struct gfs2_sbd *sdp, u64 number,
715 const struct gfs2_glock_operations *glops, int create,
716 struct gfs2_glock **glp)
717 {
718 struct super_block *s = sdp->sd_vfs;
719 struct lm_lockname name = { .ln_number = number, .ln_type = glops->go_type };
720 struct gfs2_glock *gl, *tmp;
721 unsigned int hash = gl_hash(sdp, &name);
722 struct address_space *mapping;
723 struct kmem_cache *cachep;
724
725 rcu_read_lock();
726 gl = search_bucket(hash, sdp, &name);
727 rcu_read_unlock();
728
729 *glp = gl;
730 if (gl)
731 return 0;
732 if (!create)
733 return -ENOENT;
734
735 if (glops->go_flags & GLOF_ASPACE)
736 cachep = gfs2_glock_aspace_cachep;
737 else
738 cachep = gfs2_glock_cachep;
739 gl = kmem_cache_alloc(cachep, GFP_KERNEL);
740 if (!gl)
741 return -ENOMEM;
742
743 memset(&gl->gl_lksb, 0, sizeof(struct dlm_lksb));
744
745 if (glops->go_flags & GLOF_LVB) {
746 gl->gl_lksb.sb_lvbptr = kzalloc(GFS2_MIN_LVB_SIZE, GFP_KERNEL);
747 if (!gl->gl_lksb.sb_lvbptr) {
748 kmem_cache_free(cachep, gl);
749 return -ENOMEM;
750 }
751 }
752
753 atomic_inc(&sdp->sd_glock_disposal);
754 gl->gl_sbd = sdp;
755 gl->gl_flags = 0;
756 gl->gl_name = name;
757 atomic_set(&gl->gl_ref, 1);
758 gl->gl_state = LM_ST_UNLOCKED;
759 gl->gl_target = LM_ST_UNLOCKED;
760 gl->gl_demote_state = LM_ST_EXCLUSIVE;
761 gl->gl_hash = hash;
762 gl->gl_ops = glops;
763 gl->gl_dstamp = ktime_set(0, 0);
764 preempt_disable();
765 /* We use the global stats to estimate the initial per-glock stats */
766 gl->gl_stats = this_cpu_ptr(sdp->sd_lkstats)->lkstats[glops->go_type];
767 preempt_enable();
768 gl->gl_stats.stats[GFS2_LKS_DCOUNT] = 0;
769 gl->gl_stats.stats[GFS2_LKS_QCOUNT] = 0;
770 gl->gl_tchange = jiffies;
771 gl->gl_object = NULL;
772 gl->gl_hold_time = GL_GLOCK_DFT_HOLD;
773 INIT_DELAYED_WORK(&gl->gl_work, glock_work_func);
774 INIT_WORK(&gl->gl_delete, delete_work_func);
775
776 mapping = gfs2_glock2aspace(gl);
777 if (mapping) {
778 mapping->a_ops = &gfs2_meta_aops;
779 mapping->host = s->s_bdev->bd_inode;
780 mapping->flags = 0;
781 mapping_set_gfp_mask(mapping, GFP_NOFS);
782 mapping->private_data = NULL;
783 mapping->backing_dev_info = s->s_bdi;
784 mapping->writeback_index = 0;
785 }
786
787 spin_lock_bucket(hash);
788 tmp = search_bucket(hash, sdp, &name);
789 if (tmp) {
790 spin_unlock_bucket(hash);
791 kfree(gl->gl_lksb.sb_lvbptr);
792 kmem_cache_free(cachep, gl);
793 atomic_dec(&sdp->sd_glock_disposal);
794 gl = tmp;
795 } else {
796 hlist_bl_add_head_rcu(&gl->gl_list, &gl_hash_table[hash]);
797 spin_unlock_bucket(hash);
798 }
799
800 *glp = gl;
801
802 return 0;
803 }
804
805 /**
806 * gfs2_holder_init - initialize a struct gfs2_holder in the default way
807 * @gl: the glock
808 * @state: the state we're requesting
809 * @flags: the modifier flags
810 * @gh: the holder structure
811 *
812 */
813
814 void gfs2_holder_init(struct gfs2_glock *gl, unsigned int state, unsigned flags,
815 struct gfs2_holder *gh)
816 {
817 INIT_LIST_HEAD(&gh->gh_list);
818 gh->gh_gl = gl;
819 gh->gh_ip = (unsigned long)__builtin_return_address(0);
820 gh->gh_owner_pid = get_pid(task_pid(current));
821 gh->gh_state = state;
822 gh->gh_flags = flags;
823 gh->gh_error = 0;
824 gh->gh_iflags = 0;
825 gfs2_glock_hold(gl);
826 }
827
828 /**
829 * gfs2_holder_reinit - reinitialize a struct gfs2_holder so we can requeue it
830 * @state: the state we're requesting
831 * @flags: the modifier flags
832 * @gh: the holder structure
833 *
834 * Don't mess with the glock.
835 *
836 */
837
838 void gfs2_holder_reinit(unsigned int state, unsigned flags, struct gfs2_holder *gh)
839 {
840 gh->gh_state = state;
841 gh->gh_flags = flags;
842 gh->gh_iflags = 0;
843 gh->gh_ip = (unsigned long)__builtin_return_address(0);
844 if (gh->gh_owner_pid)
845 put_pid(gh->gh_owner_pid);
846 gh->gh_owner_pid = get_pid(task_pid(current));
847 }
848
849 /**
850 * gfs2_holder_uninit - uninitialize a holder structure (drop glock reference)
851 * @gh: the holder structure
852 *
853 */
854
855 void gfs2_holder_uninit(struct gfs2_holder *gh)
856 {
857 put_pid(gh->gh_owner_pid);
858 gfs2_glock_put(gh->gh_gl);
859 gh->gh_gl = NULL;
860 gh->gh_ip = 0;
861 }
862
863 /**
864 * gfs2_glock_holder_wait
865 * @word: unused
866 *
867 * This function and gfs2_glock_demote_wait both show up in the WCHAN
868 * field. Thus I've separated these otherwise identical functions in
869 * order to be more informative to the user.
870 */
871
872 static int gfs2_glock_holder_wait(void *word)
873 {
874 schedule();
875 return 0;
876 }
877
878 static int gfs2_glock_demote_wait(void *word)
879 {
880 schedule();
881 return 0;
882 }
883
884 /**
885 * gfs2_glock_wait - wait on a glock acquisition
886 * @gh: the glock holder
887 *
888 * Returns: 0 on success
889 */
890
891 int gfs2_glock_wait(struct gfs2_holder *gh)
892 {
893 unsigned long time1 = jiffies;
894
895 might_sleep();
896 wait_on_bit(&gh->gh_iflags, HIF_WAIT, gfs2_glock_holder_wait, TASK_UNINTERRUPTIBLE);
897 if (time_after(jiffies, time1 + HZ)) /* have we waited > a second? */
898 /* Lengthen the minimum hold time. */
899 gh->gh_gl->gl_hold_time = min(gh->gh_gl->gl_hold_time +
900 GL_GLOCK_HOLD_INCR,
901 GL_GLOCK_MAX_HOLD);
902 return gh->gh_error;
903 }
904
905 /**
906 * handle_callback - process a demote request
907 * @gl: the glock
908 * @state: the state the caller wants us to change to
909 *
910 * There are only two requests that we are going to see in actual
911 * practise: LM_ST_SHARED and LM_ST_UNLOCKED
912 */
913
914 static void handle_callback(struct gfs2_glock *gl, unsigned int state,
915 unsigned long delay, bool remote)
916 {
917 int bit = delay ? GLF_PENDING_DEMOTE : GLF_DEMOTE;
918
919 set_bit(bit, &gl->gl_flags);
920 if (gl->gl_demote_state == LM_ST_EXCLUSIVE) {
921 gl->gl_demote_state = state;
922 gl->gl_demote_time = jiffies;
923 } else if (gl->gl_demote_state != LM_ST_UNLOCKED &&
924 gl->gl_demote_state != state) {
925 gl->gl_demote_state = LM_ST_UNLOCKED;
926 }
927 if (gl->gl_ops->go_callback)
928 gl->gl_ops->go_callback(gl, remote);
929 trace_gfs2_demote_rq(gl, remote);
930 }
931
932 void gfs2_print_dbg(struct seq_file *seq, const char *fmt, ...)
933 {
934 struct va_format vaf;
935 va_list args;
936
937 va_start(args, fmt);
938
939 if (seq) {
940 seq_vprintf(seq, fmt, args);
941 } else {
942 vaf.fmt = fmt;
943 vaf.va = &args;
944
945 printk(KERN_ERR " %pV", &vaf);
946 }
947
948 va_end(args);
949 }
950
951 /**
952 * add_to_queue - Add a holder to the wait queue (but look for recursion)
953 * @gh: the holder structure to add
954 *
955 * Eventually we should move the recursive locking trap to a
956 * debugging option or something like that. This is the fast
957 * path and needs to have the minimum number of distractions.
958 *
959 */
960
961 static inline void add_to_queue(struct gfs2_holder *gh)
962 __releases(&gl->gl_spin)
963 __acquires(&gl->gl_spin)
964 {
965 struct gfs2_glock *gl = gh->gh_gl;
966 struct gfs2_sbd *sdp = gl->gl_sbd;
967 struct list_head *insert_pt = NULL;
968 struct gfs2_holder *gh2;
969 int try_futile = 0;
970
971 BUG_ON(gh->gh_owner_pid == NULL);
972 if (test_and_set_bit(HIF_WAIT, &gh->gh_iflags))
973 BUG();
974
975 if (gh->gh_flags & (LM_FLAG_TRY | LM_FLAG_TRY_1CB)) {
976 if (test_bit(GLF_LOCK, &gl->gl_flags))
977 try_futile = !may_grant(gl, gh);
978 if (test_bit(GLF_INVALIDATE_IN_PROGRESS, &gl->gl_flags))
979 goto fail;
980 }
981
982 list_for_each_entry(gh2, &gl->gl_holders, gh_list) {
983 if (unlikely(gh2->gh_owner_pid == gh->gh_owner_pid &&
984 (gh->gh_gl->gl_ops->go_type != LM_TYPE_FLOCK)))
985 goto trap_recursive;
986 if (try_futile &&
987 !(gh2->gh_flags & (LM_FLAG_TRY | LM_FLAG_TRY_1CB))) {
988 fail:
989 gh->gh_error = GLR_TRYFAILED;
990 gfs2_holder_wake(gh);
991 return;
992 }
993 if (test_bit(HIF_HOLDER, &gh2->gh_iflags))
994 continue;
995 if (unlikely((gh->gh_flags & LM_FLAG_PRIORITY) && !insert_pt))
996 insert_pt = &gh2->gh_list;
997 }
998 set_bit(GLF_QUEUED, &gl->gl_flags);
999 trace_gfs2_glock_queue(gh, 1);
1000 gfs2_glstats_inc(gl, GFS2_LKS_QCOUNT);
1001 gfs2_sbstats_inc(gl, GFS2_LKS_QCOUNT);
1002 if (likely(insert_pt == NULL)) {
1003 list_add_tail(&gh->gh_list, &gl->gl_holders);
1004 if (unlikely(gh->gh_flags & LM_FLAG_PRIORITY))
1005 goto do_cancel;
1006 return;
1007 }
1008 list_add_tail(&gh->gh_list, insert_pt);
1009 do_cancel:
1010 gh = list_entry(gl->gl_holders.next, struct gfs2_holder, gh_list);
1011 if (!(gh->gh_flags & LM_FLAG_PRIORITY)) {
1012 spin_unlock(&gl->gl_spin);
1013 if (sdp->sd_lockstruct.ls_ops->lm_cancel)
1014 sdp->sd_lockstruct.ls_ops->lm_cancel(gl);
1015 spin_lock(&gl->gl_spin);
1016 }
1017 return;
1018
1019 trap_recursive:
1020 printk(KERN_ERR "original: %pSR\n", (void *)gh2->gh_ip);
1021 printk(KERN_ERR "pid: %d\n", pid_nr(gh2->gh_owner_pid));
1022 printk(KERN_ERR "lock type: %d req lock state : %d\n",
1023 gh2->gh_gl->gl_name.ln_type, gh2->gh_state);
1024 printk(KERN_ERR "new: %pSR\n", (void *)gh->gh_ip);
1025 printk(KERN_ERR "pid: %d\n", pid_nr(gh->gh_owner_pid));
1026 printk(KERN_ERR "lock type: %d req lock state : %d\n",
1027 gh->gh_gl->gl_name.ln_type, gh->gh_state);
1028 gfs2_dump_glock(NULL, gl);
1029 BUG();
1030 }
1031
1032 /**
1033 * gfs2_glock_nq - enqueue a struct gfs2_holder onto a glock (acquire a glock)
1034 * @gh: the holder structure
1035 *
1036 * if (gh->gh_flags & GL_ASYNC), this never returns an error
1037 *
1038 * Returns: 0, GLR_TRYFAILED, or errno on failure
1039 */
1040
1041 int gfs2_glock_nq(struct gfs2_holder *gh)
1042 {
1043 struct gfs2_glock *gl = gh->gh_gl;
1044 struct gfs2_sbd *sdp = gl->gl_sbd;
1045 int error = 0;
1046
1047 if (unlikely(test_bit(SDF_SHUTDOWN, &sdp->sd_flags)))
1048 return -EIO;
1049
1050 if (test_bit(GLF_LRU, &gl->gl_flags))
1051 gfs2_glock_remove_from_lru(gl);
1052
1053 spin_lock(&gl->gl_spin);
1054 add_to_queue(gh);
1055 if ((LM_FLAG_NOEXP & gh->gh_flags) &&
1056 test_and_clear_bit(GLF_FROZEN, &gl->gl_flags))
1057 set_bit(GLF_REPLY_PENDING, &gl->gl_flags);
1058 run_queue(gl, 1);
1059 spin_unlock(&gl->gl_spin);
1060
1061 if (!(gh->gh_flags & GL_ASYNC))
1062 error = gfs2_glock_wait(gh);
1063
1064 return error;
1065 }
1066
1067 /**
1068 * gfs2_glock_poll - poll to see if an async request has been completed
1069 * @gh: the holder
1070 *
1071 * Returns: 1 if the request is ready to be gfs2_glock_wait()ed on
1072 */
1073
1074 int gfs2_glock_poll(struct gfs2_holder *gh)
1075 {
1076 return test_bit(HIF_WAIT, &gh->gh_iflags) ? 0 : 1;
1077 }
1078
1079 /**
1080 * gfs2_glock_dq - dequeue a struct gfs2_holder from a glock (release a glock)
1081 * @gh: the glock holder
1082 *
1083 */
1084
1085 void gfs2_glock_dq(struct gfs2_holder *gh)
1086 {
1087 struct gfs2_glock *gl = gh->gh_gl;
1088 const struct gfs2_glock_operations *glops = gl->gl_ops;
1089 unsigned delay = 0;
1090 int fast_path = 0;
1091
1092 spin_lock(&gl->gl_spin);
1093 if (gh->gh_flags & GL_NOCACHE)
1094 handle_callback(gl, LM_ST_UNLOCKED, 0, false);
1095
1096 list_del_init(&gh->gh_list);
1097 if (find_first_holder(gl) == NULL) {
1098 if (glops->go_unlock) {
1099 GLOCK_BUG_ON(gl, test_and_set_bit(GLF_LOCK, &gl->gl_flags));
1100 spin_unlock(&gl->gl_spin);
1101 glops->go_unlock(gh);
1102 spin_lock(&gl->gl_spin);
1103 clear_bit(GLF_LOCK, &gl->gl_flags);
1104 }
1105 if (list_empty(&gl->gl_holders) &&
1106 !test_bit(GLF_PENDING_DEMOTE, &gl->gl_flags) &&
1107 !test_bit(GLF_DEMOTE, &gl->gl_flags))
1108 fast_path = 1;
1109 }
1110 if (!test_bit(GLF_LFLUSH, &gl->gl_flags) && demote_ok(gl))
1111 gfs2_glock_add_to_lru(gl);
1112
1113 trace_gfs2_glock_queue(gh, 0);
1114 spin_unlock(&gl->gl_spin);
1115 if (likely(fast_path))
1116 return;
1117
1118 gfs2_glock_hold(gl);
1119 if (test_bit(GLF_PENDING_DEMOTE, &gl->gl_flags) &&
1120 !test_bit(GLF_DEMOTE, &gl->gl_flags) &&
1121 gl->gl_name.ln_type == LM_TYPE_INODE)
1122 delay = gl->gl_hold_time;
1123 if (queue_delayed_work(glock_workqueue, &gl->gl_work, delay) == 0)
1124 gfs2_glock_put(gl);
1125 }
1126
1127 void gfs2_glock_dq_wait(struct gfs2_holder *gh)
1128 {
1129 struct gfs2_glock *gl = gh->gh_gl;
1130 gfs2_glock_dq(gh);
1131 might_sleep();
1132 wait_on_bit(&gl->gl_flags, GLF_DEMOTE, gfs2_glock_demote_wait, TASK_UNINTERRUPTIBLE);
1133 }
1134
1135 /**
1136 * gfs2_glock_dq_uninit - dequeue a holder from a glock and initialize it
1137 * @gh: the holder structure
1138 *
1139 */
1140
1141 void gfs2_glock_dq_uninit(struct gfs2_holder *gh)
1142 {
1143 gfs2_glock_dq(gh);
1144 gfs2_holder_uninit(gh);
1145 }
1146
1147 /**
1148 * gfs2_glock_nq_num - acquire a glock based on lock number
1149 * @sdp: the filesystem
1150 * @number: the lock number
1151 * @glops: the glock operations for the type of glock
1152 * @state: the state to acquire the glock in
1153 * @flags: modifier flags for the acquisition
1154 * @gh: the struct gfs2_holder
1155 *
1156 * Returns: errno
1157 */
1158
1159 int gfs2_glock_nq_num(struct gfs2_sbd *sdp, u64 number,
1160 const struct gfs2_glock_operations *glops,
1161 unsigned int state, int flags, struct gfs2_holder *gh)
1162 {
1163 struct gfs2_glock *gl;
1164 int error;
1165
1166 error = gfs2_glock_get(sdp, number, glops, CREATE, &gl);
1167 if (!error) {
1168 error = gfs2_glock_nq_init(gl, state, flags, gh);
1169 gfs2_glock_put(gl);
1170 }
1171
1172 return error;
1173 }
1174
1175 /**
1176 * glock_compare - Compare two struct gfs2_glock structures for sorting
1177 * @arg_a: the first structure
1178 * @arg_b: the second structure
1179 *
1180 */
1181
1182 static int glock_compare(const void *arg_a, const void *arg_b)
1183 {
1184 const struct gfs2_holder *gh_a = *(const struct gfs2_holder **)arg_a;
1185 const struct gfs2_holder *gh_b = *(const struct gfs2_holder **)arg_b;
1186 const struct lm_lockname *a = &gh_a->gh_gl->gl_name;
1187 const struct lm_lockname *b = &gh_b->gh_gl->gl_name;
1188
1189 if (a->ln_number > b->ln_number)
1190 return 1;
1191 if (a->ln_number < b->ln_number)
1192 return -1;
1193 BUG_ON(gh_a->gh_gl->gl_ops->go_type == gh_b->gh_gl->gl_ops->go_type);
1194 return 0;
1195 }
1196
1197 /**
1198 * nq_m_sync - synchonously acquire more than one glock in deadlock free order
1199 * @num_gh: the number of structures
1200 * @ghs: an array of struct gfs2_holder structures
1201 *
1202 * Returns: 0 on success (all glocks acquired),
1203 * errno on failure (no glocks acquired)
1204 */
1205
1206 static int nq_m_sync(unsigned int num_gh, struct gfs2_holder *ghs,
1207 struct gfs2_holder **p)
1208 {
1209 unsigned int x;
1210 int error = 0;
1211
1212 for (x = 0; x < num_gh; x++)
1213 p[x] = &ghs[x];
1214
1215 sort(p, num_gh, sizeof(struct gfs2_holder *), glock_compare, NULL);
1216
1217 for (x = 0; x < num_gh; x++) {
1218 p[x]->gh_flags &= ~(LM_FLAG_TRY | GL_ASYNC);
1219
1220 error = gfs2_glock_nq(p[x]);
1221 if (error) {
1222 while (x--)
1223 gfs2_glock_dq(p[x]);
1224 break;
1225 }
1226 }
1227
1228 return error;
1229 }
1230
1231 /**
1232 * gfs2_glock_nq_m - acquire multiple glocks
1233 * @num_gh: the number of structures
1234 * @ghs: an array of struct gfs2_holder structures
1235 *
1236 *
1237 * Returns: 0 on success (all glocks acquired),
1238 * errno on failure (no glocks acquired)
1239 */
1240
1241 int gfs2_glock_nq_m(unsigned int num_gh, struct gfs2_holder *ghs)
1242 {
1243 struct gfs2_holder *tmp[4];
1244 struct gfs2_holder **pph = tmp;
1245 int error = 0;
1246
1247 switch(num_gh) {
1248 case 0:
1249 return 0;
1250 case 1:
1251 ghs->gh_flags &= ~(LM_FLAG_TRY | GL_ASYNC);
1252 return gfs2_glock_nq(ghs);
1253 default:
1254 if (num_gh <= 4)
1255 break;
1256 pph = kmalloc(num_gh * sizeof(struct gfs2_holder *), GFP_NOFS);
1257 if (!pph)
1258 return -ENOMEM;
1259 }
1260
1261 error = nq_m_sync(num_gh, ghs, pph);
1262
1263 if (pph != tmp)
1264 kfree(pph);
1265
1266 return error;
1267 }
1268
1269 /**
1270 * gfs2_glock_dq_m - release multiple glocks
1271 * @num_gh: the number of structures
1272 * @ghs: an array of struct gfs2_holder structures
1273 *
1274 */
1275
1276 void gfs2_glock_dq_m(unsigned int num_gh, struct gfs2_holder *ghs)
1277 {
1278 while (num_gh--)
1279 gfs2_glock_dq(&ghs[num_gh]);
1280 }
1281
1282 void gfs2_glock_cb(struct gfs2_glock *gl, unsigned int state)
1283 {
1284 unsigned long delay = 0;
1285 unsigned long holdtime;
1286 unsigned long now = jiffies;
1287
1288 gfs2_glock_hold(gl);
1289 holdtime = gl->gl_tchange + gl->gl_hold_time;
1290 if (test_bit(GLF_QUEUED, &gl->gl_flags) &&
1291 gl->gl_name.ln_type == LM_TYPE_INODE) {
1292 if (time_before(now, holdtime))
1293 delay = holdtime - now;
1294 if (test_bit(GLF_REPLY_PENDING, &gl->gl_flags))
1295 delay = gl->gl_hold_time;
1296 }
1297
1298 spin_lock(&gl->gl_spin);
1299 handle_callback(gl, state, delay, true);
1300 spin_unlock(&gl->gl_spin);
1301 if (queue_delayed_work(glock_workqueue, &gl->gl_work, delay) == 0)
1302 gfs2_glock_put(gl);
1303 }
1304
1305 /**
1306 * gfs2_should_freeze - Figure out if glock should be frozen
1307 * @gl: The glock in question
1308 *
1309 * Glocks are not frozen if (a) the result of the dlm operation is
1310 * an error, (b) the locking operation was an unlock operation or
1311 * (c) if there is a "noexp" flagged request anywhere in the queue
1312 *
1313 * Returns: 1 if freezing should occur, 0 otherwise
1314 */
1315
1316 static int gfs2_should_freeze(const struct gfs2_glock *gl)
1317 {
1318 const struct gfs2_holder *gh;
1319
1320 if (gl->gl_reply & ~LM_OUT_ST_MASK)
1321 return 0;
1322 if (gl->gl_target == LM_ST_UNLOCKED)
1323 return 0;
1324
1325 list_for_each_entry(gh, &gl->gl_holders, gh_list) {
1326 if (test_bit(HIF_HOLDER, &gh->gh_iflags))
1327 continue;
1328 if (LM_FLAG_NOEXP & gh->gh_flags)
1329 return 0;
1330 }
1331
1332 return 1;
1333 }
1334
1335 /**
1336 * gfs2_glock_complete - Callback used by locking
1337 * @gl: Pointer to the glock
1338 * @ret: The return value from the dlm
1339 *
1340 * The gl_reply field is under the gl_spin lock so that it is ok
1341 * to use a bitfield shared with other glock state fields.
1342 */
1343
1344 void gfs2_glock_complete(struct gfs2_glock *gl, int ret)
1345 {
1346 struct lm_lockstruct *ls = &gl->gl_sbd->sd_lockstruct;
1347
1348 spin_lock(&gl->gl_spin);
1349 gl->gl_reply = ret;
1350
1351 if (unlikely(test_bit(DFL_BLOCK_LOCKS, &ls->ls_recover_flags))) {
1352 if (gfs2_should_freeze(gl)) {
1353 set_bit(GLF_FROZEN, &gl->gl_flags);
1354 spin_unlock(&gl->gl_spin);
1355 return;
1356 }
1357 }
1358
1359 spin_unlock(&gl->gl_spin);
1360 set_bit(GLF_REPLY_PENDING, &gl->gl_flags);
1361 smp_wmb();
1362 gfs2_glock_hold(gl);
1363 if (queue_delayed_work(glock_workqueue, &gl->gl_work, 0) == 0)
1364 gfs2_glock_put(gl);
1365 }
1366
1367 static int glock_cmp(void *priv, struct list_head *a, struct list_head *b)
1368 {
1369 struct gfs2_glock *gla, *glb;
1370
1371 gla = list_entry(a, struct gfs2_glock, gl_lru);
1372 glb = list_entry(b, struct gfs2_glock, gl_lru);
1373
1374 if (gla->gl_name.ln_number > glb->gl_name.ln_number)
1375 return 1;
1376 if (gla->gl_name.ln_number < glb->gl_name.ln_number)
1377 return -1;
1378
1379 return 0;
1380 }
1381
1382 /**
1383 * gfs2_dispose_glock_lru - Demote a list of glocks
1384 * @list: The list to dispose of
1385 *
1386 * Disposing of glocks may involve disk accesses, so that here we sort
1387 * the glocks by number (i.e. disk location of the inodes) so that if
1388 * there are any such accesses, they'll be sent in order (mostly).
1389 *
1390 * Must be called under the lru_lock, but may drop and retake this
1391 * lock. While the lru_lock is dropped, entries may vanish from the
1392 * list, but no new entries will appear on the list (since it is
1393 * private)
1394 */
1395
1396 static void gfs2_dispose_glock_lru(struct list_head *list)
1397 __releases(&lru_lock)
1398 __acquires(&lru_lock)
1399 {
1400 struct gfs2_glock *gl;
1401
1402 list_sort(NULL, list, glock_cmp);
1403
1404 while(!list_empty(list)) {
1405 gl = list_entry(list->next, struct gfs2_glock, gl_lru);
1406 list_del_init(&gl->gl_lru);
1407 clear_bit(GLF_LRU, &gl->gl_flags);
1408 gfs2_glock_hold(gl);
1409 spin_unlock(&lru_lock);
1410 spin_lock(&gl->gl_spin);
1411 if (demote_ok(gl))
1412 handle_callback(gl, LM_ST_UNLOCKED, 0, false);
1413 WARN_ON(!test_and_clear_bit(GLF_LOCK, &gl->gl_flags));
1414 smp_mb__after_clear_bit();
1415 if (queue_delayed_work(glock_workqueue, &gl->gl_work, 0) == 0)
1416 gfs2_glock_put_nolock(gl);
1417 spin_unlock(&gl->gl_spin);
1418 spin_lock(&lru_lock);
1419 }
1420 }
1421
1422 /**
1423 * gfs2_scan_glock_lru - Scan the LRU looking for locks to demote
1424 * @nr: The number of entries to scan
1425 *
1426 * This function selects the entries on the LRU which are able to
1427 * be demoted, and then kicks off the process by calling
1428 * gfs2_dispose_glock_lru() above.
1429 */
1430
1431 static void gfs2_scan_glock_lru(int nr)
1432 {
1433 struct gfs2_glock *gl;
1434 LIST_HEAD(skipped);
1435 LIST_HEAD(dispose);
1436
1437 spin_lock(&lru_lock);
1438 while(nr && !list_empty(&lru_list)) {
1439 gl = list_entry(lru_list.next, struct gfs2_glock, gl_lru);
1440
1441 /* Test for being demotable */
1442 if (!test_and_set_bit(GLF_LOCK, &gl->gl_flags)) {
1443 list_move(&gl->gl_lru, &dispose);
1444 atomic_dec(&lru_count);
1445 nr--;
1446 continue;
1447 }
1448
1449 list_move(&gl->gl_lru, &skipped);
1450 }
1451 list_splice(&skipped, &lru_list);
1452 if (!list_empty(&dispose))
1453 gfs2_dispose_glock_lru(&dispose);
1454 spin_unlock(&lru_lock);
1455 }
1456
1457 static int gfs2_shrink_glock_memory(struct shrinker *shrink,
1458 struct shrink_control *sc)
1459 {
1460 if (sc->nr_to_scan) {
1461 if (!(sc->gfp_mask & __GFP_FS))
1462 return -1;
1463 gfs2_scan_glock_lru(sc->nr_to_scan);
1464 }
1465
1466 return (atomic_read(&lru_count) / 100) * sysctl_vfs_cache_pressure;
1467 }
1468
1469 static struct shrinker glock_shrinker = {
1470 .shrink = gfs2_shrink_glock_memory,
1471 .seeks = DEFAULT_SEEKS,
1472 };
1473
1474 /**
1475 * examine_bucket - Call a function for glock in a hash bucket
1476 * @examiner: the function
1477 * @sdp: the filesystem
1478 * @bucket: the bucket
1479 *
1480 */
1481
1482 static void examine_bucket(glock_examiner examiner, const struct gfs2_sbd *sdp,
1483 unsigned int hash)
1484 {
1485 struct gfs2_glock *gl;
1486 struct hlist_bl_head *head = &gl_hash_table[hash];
1487 struct hlist_bl_node *pos;
1488
1489 rcu_read_lock();
1490 hlist_bl_for_each_entry_rcu(gl, pos, head, gl_list) {
1491 if ((gl->gl_sbd == sdp) && atomic_read(&gl->gl_ref))
1492 examiner(gl);
1493 }
1494 rcu_read_unlock();
1495 cond_resched();
1496 }
1497
1498 static void glock_hash_walk(glock_examiner examiner, const struct gfs2_sbd *sdp)
1499 {
1500 unsigned x;
1501
1502 for (x = 0; x < GFS2_GL_HASH_SIZE; x++)
1503 examine_bucket(examiner, sdp, x);
1504 }
1505
1506
1507 /**
1508 * thaw_glock - thaw out a glock which has an unprocessed reply waiting
1509 * @gl: The glock to thaw
1510 *
1511 * N.B. When we freeze a glock, we leave a ref to the glock outstanding,
1512 * so this has to result in the ref count being dropped by one.
1513 */
1514
1515 static void thaw_glock(struct gfs2_glock *gl)
1516 {
1517 if (!test_and_clear_bit(GLF_FROZEN, &gl->gl_flags))
1518 return;
1519 set_bit(GLF_REPLY_PENDING, &gl->gl_flags);
1520 gfs2_glock_hold(gl);
1521 if (queue_delayed_work(glock_workqueue, &gl->gl_work, 0) == 0)
1522 gfs2_glock_put(gl);
1523 }
1524
1525 /**
1526 * clear_glock - look at a glock and see if we can free it from glock cache
1527 * @gl: the glock to look at
1528 *
1529 */
1530
1531 static void clear_glock(struct gfs2_glock *gl)
1532 {
1533 gfs2_glock_remove_from_lru(gl);
1534
1535 spin_lock(&gl->gl_spin);
1536 if (gl->gl_state != LM_ST_UNLOCKED)
1537 handle_callback(gl, LM_ST_UNLOCKED, 0, false);
1538 spin_unlock(&gl->gl_spin);
1539 gfs2_glock_hold(gl);
1540 if (queue_delayed_work(glock_workqueue, &gl->gl_work, 0) == 0)
1541 gfs2_glock_put(gl);
1542 }
1543
1544 /**
1545 * gfs2_glock_thaw - Thaw any frozen glocks
1546 * @sdp: The super block
1547 *
1548 */
1549
1550 void gfs2_glock_thaw(struct gfs2_sbd *sdp)
1551 {
1552 glock_hash_walk(thaw_glock, sdp);
1553 }
1554
1555 static int dump_glock(struct seq_file *seq, struct gfs2_glock *gl)
1556 {
1557 int ret;
1558 spin_lock(&gl->gl_spin);
1559 ret = gfs2_dump_glock(seq, gl);
1560 spin_unlock(&gl->gl_spin);
1561 return ret;
1562 }
1563
1564 static void dump_glock_func(struct gfs2_glock *gl)
1565 {
1566 dump_glock(NULL, gl);
1567 }
1568
1569 /**
1570 * gfs2_gl_hash_clear - Empty out the glock hash table
1571 * @sdp: the filesystem
1572 * @wait: wait until it's all gone
1573 *
1574 * Called when unmounting the filesystem.
1575 */
1576
1577 void gfs2_gl_hash_clear(struct gfs2_sbd *sdp)
1578 {
1579 set_bit(SDF_SKIP_DLM_UNLOCK, &sdp->sd_flags);
1580 flush_workqueue(glock_workqueue);
1581 glock_hash_walk(clear_glock, sdp);
1582 flush_workqueue(glock_workqueue);
1583 wait_event(sdp->sd_glock_wait, atomic_read(&sdp->sd_glock_disposal) == 0);
1584 glock_hash_walk(dump_glock_func, sdp);
1585 }
1586
1587 void gfs2_glock_finish_truncate(struct gfs2_inode *ip)
1588 {
1589 struct gfs2_glock *gl = ip->i_gl;
1590 int ret;
1591
1592 ret = gfs2_truncatei_resume(ip);
1593 gfs2_assert_withdraw(gl->gl_sbd, ret == 0);
1594
1595 spin_lock(&gl->gl_spin);
1596 clear_bit(GLF_LOCK, &gl->gl_flags);
1597 run_queue(gl, 1);
1598 spin_unlock(&gl->gl_spin);
1599 }
1600
1601 static const char *state2str(unsigned state)
1602 {
1603 switch(state) {
1604 case LM_ST_UNLOCKED:
1605 return "UN";
1606 case LM_ST_SHARED:
1607 return "SH";
1608 case LM_ST_DEFERRED:
1609 return "DF";
1610 case LM_ST_EXCLUSIVE:
1611 return "EX";
1612 }
1613 return "??";
1614 }
1615
1616 static const char *hflags2str(char *buf, unsigned flags, unsigned long iflags)
1617 {
1618 char *p = buf;
1619 if (flags & LM_FLAG_TRY)
1620 *p++ = 't';
1621 if (flags & LM_FLAG_TRY_1CB)
1622 *p++ = 'T';
1623 if (flags & LM_FLAG_NOEXP)
1624 *p++ = 'e';
1625 if (flags & LM_FLAG_ANY)
1626 *p++ = 'A';
1627 if (flags & LM_FLAG_PRIORITY)
1628 *p++ = 'p';
1629 if (flags & GL_ASYNC)
1630 *p++ = 'a';
1631 if (flags & GL_EXACT)
1632 *p++ = 'E';
1633 if (flags & GL_NOCACHE)
1634 *p++ = 'c';
1635 if (test_bit(HIF_HOLDER, &iflags))
1636 *p++ = 'H';
1637 if (test_bit(HIF_WAIT, &iflags))
1638 *p++ = 'W';
1639 if (test_bit(HIF_FIRST, &iflags))
1640 *p++ = 'F';
1641 *p = 0;
1642 return buf;
1643 }
1644
1645 /**
1646 * dump_holder - print information about a glock holder
1647 * @seq: the seq_file struct
1648 * @gh: the glock holder
1649 *
1650 * Returns: 0 on success, -ENOBUFS when we run out of space
1651 */
1652
1653 static int dump_holder(struct seq_file *seq, const struct gfs2_holder *gh)
1654 {
1655 struct task_struct *gh_owner = NULL;
1656 char flags_buf[32];
1657
1658 if (gh->gh_owner_pid)
1659 gh_owner = pid_task(gh->gh_owner_pid, PIDTYPE_PID);
1660 gfs2_print_dbg(seq, " H: s:%s f:%s e:%d p:%ld [%s] %pS\n",
1661 state2str(gh->gh_state),
1662 hflags2str(flags_buf, gh->gh_flags, gh->gh_iflags),
1663 gh->gh_error,
1664 gh->gh_owner_pid ? (long)pid_nr(gh->gh_owner_pid) : -1,
1665 gh_owner ? gh_owner->comm : "(ended)",
1666 (void *)gh->gh_ip);
1667 return 0;
1668 }
1669
1670 static const char *gflags2str(char *buf, const struct gfs2_glock *gl)
1671 {
1672 const unsigned long *gflags = &gl->gl_flags;
1673 char *p = buf;
1674
1675 if (test_bit(GLF_LOCK, gflags))
1676 *p++ = 'l';
1677 if (test_bit(GLF_DEMOTE, gflags))
1678 *p++ = 'D';
1679 if (test_bit(GLF_PENDING_DEMOTE, gflags))
1680 *p++ = 'd';
1681 if (test_bit(GLF_DEMOTE_IN_PROGRESS, gflags))
1682 *p++ = 'p';
1683 if (test_bit(GLF_DIRTY, gflags))
1684 *p++ = 'y';
1685 if (test_bit(GLF_LFLUSH, gflags))
1686 *p++ = 'f';
1687 if (test_bit(GLF_INVALIDATE_IN_PROGRESS, gflags))
1688 *p++ = 'i';
1689 if (test_bit(GLF_REPLY_PENDING, gflags))
1690 *p++ = 'r';
1691 if (test_bit(GLF_INITIAL, gflags))
1692 *p++ = 'I';
1693 if (test_bit(GLF_FROZEN, gflags))
1694 *p++ = 'F';
1695 if (test_bit(GLF_QUEUED, gflags))
1696 *p++ = 'q';
1697 if (test_bit(GLF_LRU, gflags))
1698 *p++ = 'L';
1699 if (gl->gl_object)
1700 *p++ = 'o';
1701 if (test_bit(GLF_BLOCKING, gflags))
1702 *p++ = 'b';
1703 *p = 0;
1704 return buf;
1705 }
1706
1707 /**
1708 * gfs2_dump_glock - print information about a glock
1709 * @seq: The seq_file struct
1710 * @gl: the glock
1711 *
1712 * The file format is as follows:
1713 * One line per object, capital letters are used to indicate objects
1714 * G = glock, I = Inode, R = rgrp, H = holder. Glocks are not indented,
1715 * other objects are indented by a single space and follow the glock to
1716 * which they are related. Fields are indicated by lower case letters
1717 * followed by a colon and the field value, except for strings which are in
1718 * [] so that its possible to see if they are composed of spaces for
1719 * example. The field's are n = number (id of the object), f = flags,
1720 * t = type, s = state, r = refcount, e = error, p = pid.
1721 *
1722 * Returns: 0 on success, -ENOBUFS when we run out of space
1723 */
1724
1725 int gfs2_dump_glock(struct seq_file *seq, const struct gfs2_glock *gl)
1726 {
1727 const struct gfs2_glock_operations *glops = gl->gl_ops;
1728 unsigned long long dtime;
1729 const struct gfs2_holder *gh;
1730 char gflags_buf[32];
1731 int error = 0;
1732
1733 dtime = jiffies - gl->gl_demote_time;
1734 dtime *= 1000000/HZ; /* demote time in uSec */
1735 if (!test_bit(GLF_DEMOTE, &gl->gl_flags))
1736 dtime = 0;
1737 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",
1738 state2str(gl->gl_state),
1739 gl->gl_name.ln_type,
1740 (unsigned long long)gl->gl_name.ln_number,
1741 gflags2str(gflags_buf, gl),
1742 state2str(gl->gl_target),
1743 state2str(gl->gl_demote_state), dtime,
1744 atomic_read(&gl->gl_ail_count),
1745 atomic_read(&gl->gl_revokes),
1746 atomic_read(&gl->gl_ref), gl->gl_hold_time);
1747
1748 list_for_each_entry(gh, &gl->gl_holders, gh_list) {
1749 error = dump_holder(seq, gh);
1750 if (error)
1751 goto out;
1752 }
1753 if (gl->gl_state != LM_ST_UNLOCKED && glops->go_dump)
1754 error = glops->go_dump(seq, gl);
1755 out:
1756 return error;
1757 }
1758
1759 static int gfs2_glstats_seq_show(struct seq_file *seq, void *iter_ptr)
1760 {
1761 struct gfs2_glock *gl = iter_ptr;
1762
1763 seq_printf(seq, "G: n:%u/%llx rtt:%lld/%lld rttb:%lld/%lld irt:%lld/%lld dcnt: %lld qcnt: %lld\n",
1764 gl->gl_name.ln_type,
1765 (unsigned long long)gl->gl_name.ln_number,
1766 (long long)gl->gl_stats.stats[GFS2_LKS_SRTT],
1767 (long long)gl->gl_stats.stats[GFS2_LKS_SRTTVAR],
1768 (long long)gl->gl_stats.stats[GFS2_LKS_SRTTB],
1769 (long long)gl->gl_stats.stats[GFS2_LKS_SRTTVARB],
1770 (long long)gl->gl_stats.stats[GFS2_LKS_SIRT],
1771 (long long)gl->gl_stats.stats[GFS2_LKS_SIRTVAR],
1772 (long long)gl->gl_stats.stats[GFS2_LKS_DCOUNT],
1773 (long long)gl->gl_stats.stats[GFS2_LKS_QCOUNT]);
1774 return 0;
1775 }
1776
1777 static const char *gfs2_gltype[] = {
1778 "type",
1779 "reserved",
1780 "nondisk",
1781 "inode",
1782 "rgrp",
1783 "meta",
1784 "iopen",
1785 "flock",
1786 "plock",
1787 "quota",
1788 "journal",
1789 };
1790
1791 static const char *gfs2_stype[] = {
1792 [GFS2_LKS_SRTT] = "srtt",
1793 [GFS2_LKS_SRTTVAR] = "srttvar",
1794 [GFS2_LKS_SRTTB] = "srttb",
1795 [GFS2_LKS_SRTTVARB] = "srttvarb",
1796 [GFS2_LKS_SIRT] = "sirt",
1797 [GFS2_LKS_SIRTVAR] = "sirtvar",
1798 [GFS2_LKS_DCOUNT] = "dlm",
1799 [GFS2_LKS_QCOUNT] = "queue",
1800 };
1801
1802 #define GFS2_NR_SBSTATS (ARRAY_SIZE(gfs2_gltype) * ARRAY_SIZE(gfs2_stype))
1803
1804 static int gfs2_sbstats_seq_show(struct seq_file *seq, void *iter_ptr)
1805 {
1806 struct gfs2_glock_iter *gi = seq->private;
1807 struct gfs2_sbd *sdp = gi->sdp;
1808 unsigned index = gi->hash >> 3;
1809 unsigned subindex = gi->hash & 0x07;
1810 s64 value;
1811 int i;
1812
1813 if (index == 0 && subindex != 0)
1814 return 0;
1815
1816 seq_printf(seq, "%-10s %8s:", gfs2_gltype[index],
1817 (index == 0) ? "cpu": gfs2_stype[subindex]);
1818
1819 for_each_possible_cpu(i) {
1820 const struct gfs2_pcpu_lkstats *lkstats = per_cpu_ptr(sdp->sd_lkstats, i);
1821 if (index == 0) {
1822 value = i;
1823 } else {
1824 value = lkstats->lkstats[index - 1].stats[subindex];
1825 }
1826 seq_printf(seq, " %15lld", (long long)value);
1827 }
1828 seq_putc(seq, '\n');
1829 return 0;
1830 }
1831
1832 int __init gfs2_glock_init(void)
1833 {
1834 unsigned i;
1835 for(i = 0; i < GFS2_GL_HASH_SIZE; i++) {
1836 INIT_HLIST_BL_HEAD(&gl_hash_table[i]);
1837 }
1838
1839 glock_workqueue = alloc_workqueue("glock_workqueue", WQ_MEM_RECLAIM |
1840 WQ_HIGHPRI | WQ_FREEZABLE, 0);
1841 if (IS_ERR(glock_workqueue))
1842 return PTR_ERR(glock_workqueue);
1843 gfs2_delete_workqueue = alloc_workqueue("delete_workqueue",
1844 WQ_MEM_RECLAIM | WQ_FREEZABLE,
1845 0);
1846 if (IS_ERR(gfs2_delete_workqueue)) {
1847 destroy_workqueue(glock_workqueue);
1848 return PTR_ERR(gfs2_delete_workqueue);
1849 }
1850
1851 register_shrinker(&glock_shrinker);
1852
1853 return 0;
1854 }
1855
1856 void gfs2_glock_exit(void)
1857 {
1858 unregister_shrinker(&glock_shrinker);
1859 destroy_workqueue(glock_workqueue);
1860 destroy_workqueue(gfs2_delete_workqueue);
1861 }
1862
1863 static inline struct gfs2_glock *glock_hash_chain(unsigned hash)
1864 {
1865 return hlist_bl_entry(hlist_bl_first_rcu(&gl_hash_table[hash]),
1866 struct gfs2_glock, gl_list);
1867 }
1868
1869 static inline struct gfs2_glock *glock_hash_next(struct gfs2_glock *gl)
1870 {
1871 return hlist_bl_entry(rcu_dereference(gl->gl_list.next),
1872 struct gfs2_glock, gl_list);
1873 }
1874
1875 static int gfs2_glock_iter_next(struct gfs2_glock_iter *gi)
1876 {
1877 struct gfs2_glock *gl;
1878
1879 do {
1880 gl = gi->gl;
1881 if (gl) {
1882 gi->gl = glock_hash_next(gl);
1883 gi->nhash++;
1884 } else {
1885 if (gi->hash >= GFS2_GL_HASH_SIZE) {
1886 rcu_read_unlock();
1887 return 1;
1888 }
1889 gi->gl = glock_hash_chain(gi->hash);
1890 gi->nhash = 0;
1891 }
1892 while (gi->gl == NULL) {
1893 gi->hash++;
1894 if (gi->hash >= GFS2_GL_HASH_SIZE) {
1895 rcu_read_unlock();
1896 return 1;
1897 }
1898 gi->gl = glock_hash_chain(gi->hash);
1899 gi->nhash = 0;
1900 }
1901 /* Skip entries for other sb and dead entries */
1902 } while (gi->sdp != gi->gl->gl_sbd || atomic_read(&gi->gl->gl_ref) == 0);
1903
1904 return 0;
1905 }
1906
1907 static void *gfs2_glock_seq_start(struct seq_file *seq, loff_t *pos)
1908 {
1909 struct gfs2_glock_iter *gi = seq->private;
1910 loff_t n = *pos;
1911
1912 if (gi->last_pos <= *pos)
1913 n = gi->nhash + (*pos - gi->last_pos);
1914 else
1915 gi->hash = 0;
1916
1917 gi->nhash = 0;
1918 rcu_read_lock();
1919
1920 do {
1921 if (gfs2_glock_iter_next(gi))
1922 return NULL;
1923 } while (n--);
1924
1925 gi->last_pos = *pos;
1926 return gi->gl;
1927 }
1928
1929 static void *gfs2_glock_seq_next(struct seq_file *seq, void *iter_ptr,
1930 loff_t *pos)
1931 {
1932 struct gfs2_glock_iter *gi = seq->private;
1933
1934 (*pos)++;
1935 gi->last_pos = *pos;
1936 if (gfs2_glock_iter_next(gi))
1937 return NULL;
1938
1939 return gi->gl;
1940 }
1941
1942 static void gfs2_glock_seq_stop(struct seq_file *seq, void *iter_ptr)
1943 {
1944 struct gfs2_glock_iter *gi = seq->private;
1945
1946 if (gi->gl)
1947 rcu_read_unlock();
1948 gi->gl = NULL;
1949 }
1950
1951 static int gfs2_glock_seq_show(struct seq_file *seq, void *iter_ptr)
1952 {
1953 return dump_glock(seq, iter_ptr);
1954 }
1955
1956 static void *gfs2_sbstats_seq_start(struct seq_file *seq, loff_t *pos)
1957 {
1958 struct gfs2_glock_iter *gi = seq->private;
1959
1960 gi->hash = *pos;
1961 if (*pos >= GFS2_NR_SBSTATS)
1962 return NULL;
1963 preempt_disable();
1964 return SEQ_START_TOKEN;
1965 }
1966
1967 static void *gfs2_sbstats_seq_next(struct seq_file *seq, void *iter_ptr,
1968 loff_t *pos)
1969 {
1970 struct gfs2_glock_iter *gi = seq->private;
1971 (*pos)++;
1972 gi->hash++;
1973 if (gi->hash >= GFS2_NR_SBSTATS) {
1974 preempt_enable();
1975 return NULL;
1976 }
1977 return SEQ_START_TOKEN;
1978 }
1979
1980 static void gfs2_sbstats_seq_stop(struct seq_file *seq, void *iter_ptr)
1981 {
1982 preempt_enable();
1983 }
1984
1985 static const struct seq_operations gfs2_glock_seq_ops = {
1986 .start = gfs2_glock_seq_start,
1987 .next = gfs2_glock_seq_next,
1988 .stop = gfs2_glock_seq_stop,
1989 .show = gfs2_glock_seq_show,
1990 };
1991
1992 static const struct seq_operations gfs2_glstats_seq_ops = {
1993 .start = gfs2_glock_seq_start,
1994 .next = gfs2_glock_seq_next,
1995 .stop = gfs2_glock_seq_stop,
1996 .show = gfs2_glstats_seq_show,
1997 };
1998
1999 static const struct seq_operations gfs2_sbstats_seq_ops = {
2000 .start = gfs2_sbstats_seq_start,
2001 .next = gfs2_sbstats_seq_next,
2002 .stop = gfs2_sbstats_seq_stop,
2003 .show = gfs2_sbstats_seq_show,
2004 };
2005
2006 #define GFS2_SEQ_GOODSIZE min(PAGE_SIZE << PAGE_ALLOC_COSTLY_ORDER, 65536UL)
2007
2008 static int gfs2_glocks_open(struct inode *inode, struct file *file)
2009 {
2010 int ret = seq_open_private(file, &gfs2_glock_seq_ops,
2011 sizeof(struct gfs2_glock_iter));
2012 if (ret == 0) {
2013 struct seq_file *seq = file->private_data;
2014 struct gfs2_glock_iter *gi = seq->private;
2015 gi->sdp = inode->i_private;
2016 seq->buf = kmalloc(GFS2_SEQ_GOODSIZE, GFP_KERNEL | __GFP_NOWARN);
2017 if (seq->buf)
2018 seq->size = GFS2_SEQ_GOODSIZE;
2019 }
2020 return ret;
2021 }
2022
2023 static int gfs2_glstats_open(struct inode *inode, struct file *file)
2024 {
2025 int ret = seq_open_private(file, &gfs2_glstats_seq_ops,
2026 sizeof(struct gfs2_glock_iter));
2027 if (ret == 0) {
2028 struct seq_file *seq = file->private_data;
2029 struct gfs2_glock_iter *gi = seq->private;
2030 gi->sdp = inode->i_private;
2031 seq->buf = kmalloc(GFS2_SEQ_GOODSIZE, GFP_KERNEL | __GFP_NOWARN);
2032 if (seq->buf)
2033 seq->size = GFS2_SEQ_GOODSIZE;
2034 }
2035 return ret;
2036 }
2037
2038 static int gfs2_sbstats_open(struct inode *inode, struct file *file)
2039 {
2040 int ret = seq_open_private(file, &gfs2_sbstats_seq_ops,
2041 sizeof(struct gfs2_glock_iter));
2042 if (ret == 0) {
2043 struct seq_file *seq = file->private_data;
2044 struct gfs2_glock_iter *gi = seq->private;
2045 gi->sdp = inode->i_private;
2046 }
2047 return ret;
2048 }
2049
2050 static const struct file_operations gfs2_glocks_fops = {
2051 .owner = THIS_MODULE,
2052 .open = gfs2_glocks_open,
2053 .read = seq_read,
2054 .llseek = seq_lseek,
2055 .release = seq_release_private,
2056 };
2057
2058 static const struct file_operations gfs2_glstats_fops = {
2059 .owner = THIS_MODULE,
2060 .open = gfs2_glstats_open,
2061 .read = seq_read,
2062 .llseek = seq_lseek,
2063 .release = seq_release_private,
2064 };
2065
2066 static const struct file_operations gfs2_sbstats_fops = {
2067 .owner = THIS_MODULE,
2068 .open = gfs2_sbstats_open,
2069 .read = seq_read,
2070 .llseek = seq_lseek,
2071 .release = seq_release_private,
2072 };
2073
2074 int gfs2_create_debugfs_file(struct gfs2_sbd *sdp)
2075 {
2076 sdp->debugfs_dir = debugfs_create_dir(sdp->sd_table_name, gfs2_root);
2077 if (!sdp->debugfs_dir)
2078 return -ENOMEM;
2079 sdp->debugfs_dentry_glocks = debugfs_create_file("glocks",
2080 S_IFREG | S_IRUGO,
2081 sdp->debugfs_dir, sdp,
2082 &gfs2_glocks_fops);
2083 if (!sdp->debugfs_dentry_glocks)
2084 goto fail;
2085
2086 sdp->debugfs_dentry_glstats = debugfs_create_file("glstats",
2087 S_IFREG | S_IRUGO,
2088 sdp->debugfs_dir, sdp,
2089 &gfs2_glstats_fops);
2090 if (!sdp->debugfs_dentry_glstats)
2091 goto fail;
2092
2093 sdp->debugfs_dentry_sbstats = debugfs_create_file("sbstats",
2094 S_IFREG | S_IRUGO,
2095 sdp->debugfs_dir, sdp,
2096 &gfs2_sbstats_fops);
2097 if (!sdp->debugfs_dentry_sbstats)
2098 goto fail;
2099
2100 return 0;
2101 fail:
2102 gfs2_delete_debugfs_file(sdp);
2103 return -ENOMEM;
2104 }
2105
2106 void gfs2_delete_debugfs_file(struct gfs2_sbd *sdp)
2107 {
2108 if (sdp->debugfs_dir) {
2109 if (sdp->debugfs_dentry_glocks) {
2110 debugfs_remove(sdp->debugfs_dentry_glocks);
2111 sdp->debugfs_dentry_glocks = NULL;
2112 }
2113 if (sdp->debugfs_dentry_glstats) {
2114 debugfs_remove(sdp->debugfs_dentry_glstats);
2115 sdp->debugfs_dentry_glstats = NULL;
2116 }
2117 if (sdp->debugfs_dentry_sbstats) {
2118 debugfs_remove(sdp->debugfs_dentry_sbstats);
2119 sdp->debugfs_dentry_sbstats = NULL;
2120 }
2121 debugfs_remove(sdp->debugfs_dir);
2122 sdp->debugfs_dir = NULL;
2123 }
2124 }
2125
2126 int gfs2_register_debugfs(void)
2127 {
2128 gfs2_root = debugfs_create_dir("gfs2", NULL);
2129 return gfs2_root ? 0 : -ENOMEM;
2130 }
2131
2132 void gfs2_unregister_debugfs(void)
2133 {
2134 debugfs_remove(gfs2_root);
2135 gfs2_root = NULL;
2136 }
Linus' kernel tree