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KVM/s390: Set preempted flag during vcpu wakeup and interrupt delivery
[linux-2.6/btrfs-unstable.git] / fs / gfs2 / glock.c
blobca0be6c69a26dd0e46d07ddbdc149fb301e5a4b6
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 #include <linux/lockref.h>
35
36 #include "gfs2.h"
37 #include "incore.h"
38 #include "glock.h"
39 #include "glops.h"
40 #include "inode.h"
41 #include "lops.h"
42 #include "meta_io.h"
43 #include "quota.h"
44 #include "super.h"
45 #include "util.h"
46 #include "bmap.h"
47 #define CREATE_TRACE_POINTS
48 #include "trace_gfs2.h"
49
50 struct gfs2_glock_iter {
51 int hash; /* hash bucket index */
52 unsigned nhash; /* Index within current bucket */
53 struct gfs2_sbd *sdp; /* incore superblock */
54 struct gfs2_glock *gl; /* current glock struct */
55 loff_t last_pos; /* last position */
56 };
57
58 typedef void (*glock_examiner) (struct gfs2_glock * gl);
59
60 static void do_xmote(struct gfs2_glock *gl, struct gfs2_holder *gh, unsigned int target);
61
62 static struct dentry *gfs2_root;
63 static struct workqueue_struct *glock_workqueue;
64 struct workqueue_struct *gfs2_delete_workqueue;
65 static LIST_HEAD(lru_list);
66 static atomic_t lru_count = ATOMIC_INIT(0);
67 static DEFINE_SPINLOCK(lru_lock);
68
69 #define GFS2_GL_HASH_SHIFT 15
70 #define GFS2_GL_HASH_SIZE (1 << GFS2_GL_HASH_SHIFT)
71 #define GFS2_GL_HASH_MASK (GFS2_GL_HASH_SIZE - 1)
72
73 static struct hlist_bl_head gl_hash_table[GFS2_GL_HASH_SIZE];
74 static struct dentry *gfs2_root;
75
76 /**
77 * gl_hash() - Turn glock number into hash bucket number
78 * @lock: The glock number
79 *
80 * Returns: The number of the corresponding hash bucket
81 */
82
83 static unsigned int gl_hash(const struct gfs2_sbd *sdp,
84 const struct lm_lockname *name)
85 {
86 unsigned int h;
87
88 h = jhash(&name->ln_number, sizeof(u64), 0);
89 h = jhash(&name->ln_type, sizeof(unsigned int), h);
90 h = jhash(&sdp, sizeof(struct gfs2_sbd *), h);
91 h &= GFS2_GL_HASH_MASK;
92
93 return h;
94 }
95
96 static inline void spin_lock_bucket(unsigned int hash)
97 {
98 hlist_bl_lock(&gl_hash_table[hash]);
99 }
100
101 static inline void spin_unlock_bucket(unsigned int hash)
102 {
103 hlist_bl_unlock(&gl_hash_table[hash]);
104 }
105
106 static void gfs2_glock_dealloc(struct rcu_head *rcu)
107 {
108 struct gfs2_glock *gl = container_of(rcu, struct gfs2_glock, gl_rcu);
109
110 if (gl->gl_ops->go_flags & GLOF_ASPACE) {
111 kmem_cache_free(gfs2_glock_aspace_cachep, gl);
112 } else {
113 kfree(gl->gl_lksb.sb_lvbptr);
114 kmem_cache_free(gfs2_glock_cachep, gl);
115 }
116 }
117
118 void gfs2_glock_free(struct gfs2_glock *gl)
119 {
120 struct gfs2_sbd *sdp = gl->gl_sbd;
121
122 call_rcu(&gl->gl_rcu, gfs2_glock_dealloc);
123 if (atomic_dec_and_test(&sdp->sd_glock_disposal))
124 wake_up(&sdp->sd_glock_wait);
125 }
126
127 /**
128 * gfs2_glock_hold() - increment reference count on glock
129 * @gl: The glock to hold
130 *
131 */
132
133 static void gfs2_glock_hold(struct gfs2_glock *gl)
134 {
135 GLOCK_BUG_ON(gl, __lockref_is_dead(&gl->gl_lockref));
136 lockref_get(&gl->gl_lockref);
137 }
138
139 /**
140 * demote_ok - Check to see if it's ok to unlock a glock
141 * @gl: the glock
142 *
143 * Returns: 1 if it's ok
144 */
145
146 static int demote_ok(const struct gfs2_glock *gl)
147 {
148 const struct gfs2_glock_operations *glops = gl->gl_ops;
149
150 if (gl->gl_state == LM_ST_UNLOCKED)
151 return 0;
152 if (!list_empty(&gl->gl_holders))
153 return 0;
154 if (glops->go_demote_ok)
155 return glops->go_demote_ok(gl);
156 return 1;
157 }
158
159
160 void gfs2_glock_add_to_lru(struct gfs2_glock *gl)
161 {
162 spin_lock(&lru_lock);
163
164 if (!list_empty(&gl->gl_lru))
165 list_del_init(&gl->gl_lru);
166 else
167 atomic_inc(&lru_count);
168
169 list_add_tail(&gl->gl_lru, &lru_list);
170 set_bit(GLF_LRU, &gl->gl_flags);
171 spin_unlock(&lru_lock);
172 }
173
174 static void __gfs2_glock_remove_from_lru(struct gfs2_glock *gl)
175 {
176 if (!list_empty(&gl->gl_lru)) {
177 list_del_init(&gl->gl_lru);
178 atomic_dec(&lru_count);
179 clear_bit(GLF_LRU, &gl->gl_flags);
180 }
181 }
182
183 static void gfs2_glock_remove_from_lru(struct gfs2_glock *gl)
184 {
185 spin_lock(&lru_lock);
186 __gfs2_glock_remove_from_lru(gl);
187 spin_unlock(&lru_lock);
188 }
189
190 /**
191 * gfs2_glock_put() - Decrement reference count on glock
192 * @gl: The glock to put
193 *
194 */
195
196 void gfs2_glock_put(struct gfs2_glock *gl)
197 {
198 struct gfs2_sbd *sdp = gl->gl_sbd;
199 struct address_space *mapping = gfs2_glock2aspace(gl);
200
201 if (lockref_put_or_lock(&gl->gl_lockref))
202 return;
203
204 lockref_mark_dead(&gl->gl_lockref);
205
206 spin_lock(&lru_lock);
207 __gfs2_glock_remove_from_lru(gl);
208 spin_unlock(&lru_lock);
209 spin_unlock(&gl->gl_lockref.lock);
210 spin_lock_bucket(gl->gl_hash);
211 hlist_bl_del_rcu(&gl->gl_list);
212 spin_unlock_bucket(gl->gl_hash);
213 GLOCK_BUG_ON(gl, !list_empty(&gl->gl_holders));
214 GLOCK_BUG_ON(gl, mapping && mapping->nrpages);
215 trace_gfs2_glock_put(gl);
216 sdp->sd_lockstruct.ls_ops->lm_put_lock(gl);
217 }
218
219 /**
220 * search_bucket() - Find struct gfs2_glock by lock number
221 * @bucket: the bucket to search
222 * @name: The lock name
223 *
224 * Returns: NULL, or the struct gfs2_glock with the requested number
225 */
226
227 static struct gfs2_glock *search_bucket(unsigned int hash,
228 const struct gfs2_sbd *sdp,
229 const struct lm_lockname *name)
230 {
231 struct gfs2_glock *gl;
232 struct hlist_bl_node *h;
233
234 hlist_bl_for_each_entry_rcu(gl, h, &gl_hash_table[hash], gl_list) {
235 if (!lm_name_equal(&gl->gl_name, name))
236 continue;
237 if (gl->gl_sbd != sdp)
238 continue;
239 if (lockref_get_not_dead(&gl->gl_lockref))
240 return gl;
241 }
242
243 return NULL;
244 }
245
246 /**
247 * may_grant - check if its ok to grant a new lock
248 * @gl: The glock
249 * @gh: The lock request which we wish to grant
250 *
251 * Returns: true if its ok to grant the lock
252 */
253
254 static inline int may_grant(const struct gfs2_glock *gl, const struct gfs2_holder *gh)
255 {
256 const struct gfs2_holder *gh_head = list_entry(gl->gl_holders.next, const struct gfs2_holder, gh_list);
257 if ((gh->gh_state == LM_ST_EXCLUSIVE ||
258 gh_head->gh_state == LM_ST_EXCLUSIVE) && gh != gh_head)
259 return 0;
260 if (gl->gl_state == gh->gh_state)
261 return 1;
262 if (gh->gh_flags & GL_EXACT)
263 return 0;
264 if (gl->gl_state == LM_ST_EXCLUSIVE) {
265 if (gh->gh_state == LM_ST_SHARED && gh_head->gh_state == LM_ST_SHARED)
266 return 1;
267 if (gh->gh_state == LM_ST_DEFERRED && gh_head->gh_state == LM_ST_DEFERRED)
268 return 1;
269 }
270 if (gl->gl_state != LM_ST_UNLOCKED && (gh->gh_flags & LM_FLAG_ANY))
271 return 1;
272 return 0;
273 }
274
275 static void gfs2_holder_wake(struct gfs2_holder *gh)
276 {
277 clear_bit(HIF_WAIT, &gh->gh_iflags);
278 smp_mb__after_clear_bit();
279 wake_up_bit(&gh->gh_iflags, HIF_WAIT);
280 }
281
282 /**
283 * do_error - Something unexpected has happened during a lock request
284 *
285 */
286
287 static inline void do_error(struct gfs2_glock *gl, const int ret)
288 {
289 struct gfs2_holder *gh, *tmp;
290
291 list_for_each_entry_safe(gh, tmp, &gl->gl_holders, gh_list) {
292 if (test_bit(HIF_HOLDER, &gh->gh_iflags))
293 continue;
294 if (ret & LM_OUT_ERROR)
295 gh->gh_error = -EIO;
296 else if (gh->gh_flags & (LM_FLAG_TRY | LM_FLAG_TRY_1CB))
297 gh->gh_error = GLR_TRYFAILED;
298 else
299 continue;
300 list_del_init(&gh->gh_list);
301 trace_gfs2_glock_queue(gh, 0);
302 gfs2_holder_wake(gh);
303 }
304 }
305
306 /**
307 * do_promote - promote as many requests as possible on the current queue
308 * @gl: The glock
309 *
310 * Returns: 1 if there is a blocked holder at the head of the list, or 2
311 * if a type specific operation is underway.
312 */
313
314 static int do_promote(struct gfs2_glock *gl)
315 __releases(&gl->gl_spin)
316 __acquires(&gl->gl_spin)
317 {
318 const struct gfs2_glock_operations *glops = gl->gl_ops;
319 struct gfs2_holder *gh, *tmp;
320 int ret;
321
322 restart:
323 list_for_each_entry_safe(gh, tmp, &gl->gl_holders, gh_list) {
324 if (test_bit(HIF_HOLDER, &gh->gh_iflags))
325 continue;
326 if (may_grant(gl, gh)) {
327 if (gh->gh_list.prev == &gl->gl_holders &&
328 glops->go_lock) {
329 spin_unlock(&gl->gl_spin);
330 /* FIXME: eliminate this eventually */
331 ret = glops->go_lock(gh);
332 spin_lock(&gl->gl_spin);
333 if (ret) {
334 if (ret == 1)
335 return 2;
336 gh->gh_error = ret;
337 list_del_init(&gh->gh_list);
338 trace_gfs2_glock_queue(gh, 0);
339 gfs2_holder_wake(gh);
340 goto restart;
341 }
342 set_bit(HIF_HOLDER, &gh->gh_iflags);
343 trace_gfs2_promote(gh, 1);
344 gfs2_holder_wake(gh);
345 goto restart;
346 }
347 set_bit(HIF_HOLDER, &gh->gh_iflags);
348 trace_gfs2_promote(gh, 0);
349 gfs2_holder_wake(gh);
350 continue;
351 }
352 if (gh->gh_list.prev == &gl->gl_holders)
353 return 1;
354 do_error(gl, 0);
355 break;
356 }
357 return 0;
358 }
359
360 /**
361 * find_first_waiter - find the first gh that's waiting for the glock
362 * @gl: the glock
363 */
364
365 static inline struct gfs2_holder *find_first_waiter(const struct gfs2_glock *gl)
366 {
367 struct gfs2_holder *gh;
368
369 list_for_each_entry(gh, &gl->gl_holders, gh_list) {
370 if (!test_bit(HIF_HOLDER, &gh->gh_iflags))
371 return gh;
372 }
373 return NULL;
374 }
375
376 /**
377 * state_change - record that the glock is now in a different state
378 * @gl: the glock
379 * @new_state the new state
380 *
381 */
382
383 static void state_change(struct gfs2_glock *gl, unsigned int new_state)
384 {
385 int held1, held2;
386
387 held1 = (gl->gl_state != LM_ST_UNLOCKED);
388 held2 = (new_state != LM_ST_UNLOCKED);
389
390 if (held1 != held2) {
391 GLOCK_BUG_ON(gl, __lockref_is_dead(&gl->gl_lockref));
392 if (held2)
393 gl->gl_lockref.count++;
394 else
395 gl->gl_lockref.count--;
396 }
397 if (held1 && held2 && list_empty(&gl->gl_holders))
398 clear_bit(GLF_QUEUED, &gl->gl_flags);
399
400 if (new_state != gl->gl_target)
401 /* shorten our minimum hold time */
402 gl->gl_hold_time = max(gl->gl_hold_time - GL_GLOCK_HOLD_DECR,
403 GL_GLOCK_MIN_HOLD);
404 gl->gl_state = new_state;
405 gl->gl_tchange = jiffies;
406 }
407
408 static void gfs2_demote_wake(struct gfs2_glock *gl)
409 {
410 gl->gl_demote_state = LM_ST_EXCLUSIVE;
411 clear_bit(GLF_DEMOTE, &gl->gl_flags);
412 smp_mb__after_clear_bit();
413 wake_up_bit(&gl->gl_flags, GLF_DEMOTE);
414 }
415
416 /**
417 * finish_xmote - The DLM has replied to one of our lock requests
418 * @gl: The glock
419 * @ret: The status from the DLM
420 *
421 */
422
423 static void finish_xmote(struct gfs2_glock *gl, unsigned int ret)
424 {
425 const struct gfs2_glock_operations *glops = gl->gl_ops;
426 struct gfs2_holder *gh;
427 unsigned state = ret & LM_OUT_ST_MASK;
428 int rv;
429
430 spin_lock(&gl->gl_spin);
431 trace_gfs2_glock_state_change(gl, state);
432 state_change(gl, state);
433 gh = find_first_waiter(gl);
434
435 /* Demote to UN request arrived during demote to SH or DF */
436 if (test_bit(GLF_DEMOTE_IN_PROGRESS, &gl->gl_flags) &&
437 state != LM_ST_UNLOCKED && gl->gl_demote_state == LM_ST_UNLOCKED)
438 gl->gl_target = LM_ST_UNLOCKED;
439
440 /* Check for state != intended state */
441 if (unlikely(state != gl->gl_target)) {
442 if (gh && !test_bit(GLF_DEMOTE_IN_PROGRESS, &gl->gl_flags)) {
443 /* move to back of queue and try next entry */
444 if (ret & LM_OUT_CANCELED) {
445 if ((gh->gh_flags & LM_FLAG_PRIORITY) == 0)
446 list_move_tail(&gh->gh_list, &gl->gl_holders);
447 gh = find_first_waiter(gl);
448 gl->gl_target = gh->gh_state;
449 goto retry;
450 }
451 /* Some error or failed "try lock" - report it */
452 if ((ret & LM_OUT_ERROR) ||
453 (gh->gh_flags & (LM_FLAG_TRY | LM_FLAG_TRY_1CB))) {
454 gl->gl_target = gl->gl_state;
455 do_error(gl, ret);
456 goto out;
457 }
458 }
459 switch(state) {
460 /* Unlocked due to conversion deadlock, try again */
461 case LM_ST_UNLOCKED:
462 retry:
463 do_xmote(gl, gh, gl->gl_target);
464 break;
465 /* Conversion fails, unlock and try again */
466 case LM_ST_SHARED:
467 case LM_ST_DEFERRED:
468 do_xmote(gl, gh, LM_ST_UNLOCKED);
469 break;
470 default: /* Everything else */
471 printk(KERN_ERR "GFS2: wanted %u got %u\n", gl->gl_target, state);
472 GLOCK_BUG_ON(gl, 1);
473 }
474 spin_unlock(&gl->gl_spin);
475 return;
476 }
477
478 /* Fast path - we got what we asked for */
479 if (test_and_clear_bit(GLF_DEMOTE_IN_PROGRESS, &gl->gl_flags))
480 gfs2_demote_wake(gl);
481 if (state != LM_ST_UNLOCKED) {
482 if (glops->go_xmote_bh) {
483 spin_unlock(&gl->gl_spin);
484 rv = glops->go_xmote_bh(gl, gh);
485 spin_lock(&gl->gl_spin);
486 if (rv) {
487 do_error(gl, rv);
488 goto out;
489 }
490 }
491 rv = do_promote(gl);
492 if (rv == 2)
493 goto out_locked;
494 }
495 out:
496 clear_bit(GLF_LOCK, &gl->gl_flags);
497 out_locked:
498 spin_unlock(&gl->gl_spin);
499 }
500
501 /**
502 * do_xmote - Calls the DLM to change the state of a lock
503 * @gl: The lock state
504 * @gh: The holder (only for promotes)
505 * @target: The target lock state
506 *
507 */
508
509 static void do_xmote(struct gfs2_glock *gl, struct gfs2_holder *gh, unsigned int target)
510 __releases(&gl->gl_spin)
511 __acquires(&gl->gl_spin)
512 {
513 const struct gfs2_glock_operations *glops = gl->gl_ops;
514 struct gfs2_sbd *sdp = gl->gl_sbd;
515 unsigned int lck_flags = gh ? gh->gh_flags : 0;
516 int ret;
517
518 lck_flags &= (LM_FLAG_TRY | LM_FLAG_TRY_1CB | LM_FLAG_NOEXP |
519 LM_FLAG_PRIORITY);
520 GLOCK_BUG_ON(gl, gl->gl_state == target);
521 GLOCK_BUG_ON(gl, gl->gl_state == gl->gl_target);
522 if ((target == LM_ST_UNLOCKED || target == LM_ST_DEFERRED) &&
523 glops->go_inval) {
524 set_bit(GLF_INVALIDATE_IN_PROGRESS, &gl->gl_flags);
525 do_error(gl, 0); /* Fail queued try locks */
526 }
527 gl->gl_req = target;
528 set_bit(GLF_BLOCKING, &gl->gl_flags);
529 if ((gl->gl_req == LM_ST_UNLOCKED) ||
530 (gl->gl_state == LM_ST_EXCLUSIVE) ||
531 (lck_flags & (LM_FLAG_TRY|LM_FLAG_TRY_1CB)))
532 clear_bit(GLF_BLOCKING, &gl->gl_flags);
533 spin_unlock(&gl->gl_spin);
534 if (glops->go_sync)
535 glops->go_sync(gl);
536 if (test_bit(GLF_INVALIDATE_IN_PROGRESS, &gl->gl_flags))
537 glops->go_inval(gl, target == LM_ST_DEFERRED ? 0 : DIO_METADATA);
538 clear_bit(GLF_INVALIDATE_IN_PROGRESS, &gl->gl_flags);
539
540 gfs2_glock_hold(gl);
541 if (sdp->sd_lockstruct.ls_ops->lm_lock) {
542 /* lock_dlm */
543 ret = sdp->sd_lockstruct.ls_ops->lm_lock(gl, target, lck_flags);
544 if (ret) {
545 printk(KERN_ERR "GFS2: lm_lock ret %d\n", ret);
546 GLOCK_BUG_ON(gl, 1);
547 }
548 } else { /* lock_nolock */
549 finish_xmote(gl, target);
550 if (queue_delayed_work(glock_workqueue, &gl->gl_work, 0) == 0)
551 gfs2_glock_put(gl);
552 }
553
554 spin_lock(&gl->gl_spin);
555 }
556
557 /**
558 * find_first_holder - find the first "holder" gh
559 * @gl: the glock
560 */
561
562 static inline struct gfs2_holder *find_first_holder(const struct gfs2_glock *gl)
563 {
564 struct gfs2_holder *gh;
565
566 if (!list_empty(&gl->gl_holders)) {
567 gh = list_entry(gl->gl_holders.next, struct gfs2_holder, gh_list);
568 if (test_bit(HIF_HOLDER, &gh->gh_iflags))
569 return gh;
570 }
571 return NULL;
572 }
573
574 /**
575 * run_queue - do all outstanding tasks related to a glock
576 * @gl: The glock in question
577 * @nonblock: True if we must not block in run_queue
578 *
579 */
580
581 static void run_queue(struct gfs2_glock *gl, const int nonblock)
582 __releases(&gl->gl_spin)
583 __acquires(&gl->gl_spin)
584 {
585 struct gfs2_holder *gh = NULL;
586 int ret;
587
588 if (test_and_set_bit(GLF_LOCK, &gl->gl_flags))
589 return;
590
591 GLOCK_BUG_ON(gl, test_bit(GLF_DEMOTE_IN_PROGRESS, &gl->gl_flags));
592
593 if (test_bit(GLF_DEMOTE, &gl->gl_flags) &&
594 gl->gl_demote_state != gl->gl_state) {
595 if (find_first_holder(gl))
596 goto out_unlock;
597 if (nonblock)
598 goto out_sched;
599 set_bit(GLF_DEMOTE_IN_PROGRESS, &gl->gl_flags);
600 GLOCK_BUG_ON(gl, gl->gl_demote_state == LM_ST_EXCLUSIVE);
601 gl->gl_target = gl->gl_demote_state;
602 } else {
603 if (test_bit(GLF_DEMOTE, &gl->gl_flags))
604 gfs2_demote_wake(gl);
605 ret = do_promote(gl);
606 if (ret == 0)
607 goto out_unlock;
608 if (ret == 2)
609 goto out;
610 gh = find_first_waiter(gl);
611 gl->gl_target = gh->gh_state;
612 if (!(gh->gh_flags & (LM_FLAG_TRY | LM_FLAG_TRY_1CB)))
613 do_error(gl, 0); /* Fail queued try locks */
614 }
615 do_xmote(gl, gh, gl->gl_target);
616 out:
617 return;
618
619 out_sched:
620 clear_bit(GLF_LOCK, &gl->gl_flags);
621 smp_mb__after_clear_bit();
622 gl->gl_lockref.count++;
623 if (queue_delayed_work(glock_workqueue, &gl->gl_work, 0) == 0)
624 gl->gl_lockref.count--;
625 return;
626
627 out_unlock:
628 clear_bit(GLF_LOCK, &gl->gl_flags);
629 smp_mb__after_clear_bit();
630 return;
631 }
632
633 static void delete_work_func(struct work_struct *work)
634 {
635 struct gfs2_glock *gl = container_of(work, struct gfs2_glock, gl_delete);
636 struct gfs2_sbd *sdp = gl->gl_sbd;
637 struct gfs2_inode *ip;
638 struct inode *inode;
639 u64 no_addr = gl->gl_name.ln_number;
640
641 ip = gl->gl_object;
642 /* Note: Unsafe to dereference ip as we don't hold right refs/locks */
643
644 if (ip)
645 inode = gfs2_ilookup(sdp->sd_vfs, no_addr, 1);
646 else
647 inode = gfs2_lookup_by_inum(sdp, no_addr, NULL, GFS2_BLKST_UNLINKED);
648 if (inode && !IS_ERR(inode)) {
649 d_prune_aliases(inode);
650 iput(inode);
651 }
652 gfs2_glock_put(gl);
653 }
654
655 static void glock_work_func(struct work_struct *work)
656 {
657 unsigned long delay = 0;
658 struct gfs2_glock *gl = container_of(work, struct gfs2_glock, gl_work.work);
659 int drop_ref = 0;
660
661 if (test_and_clear_bit(GLF_REPLY_PENDING, &gl->gl_flags)) {
662 finish_xmote(gl, gl->gl_reply);
663 drop_ref = 1;
664 }
665 spin_lock(&gl->gl_spin);
666 if (test_bit(GLF_PENDING_DEMOTE, &gl->gl_flags) &&
667 gl->gl_state != LM_ST_UNLOCKED &&
668 gl->gl_demote_state != LM_ST_EXCLUSIVE) {
669 unsigned long holdtime, now = jiffies;
670
671 holdtime = gl->gl_tchange + gl->gl_hold_time;
672 if (time_before(now, holdtime))
673 delay = holdtime - now;
674
675 if (!delay) {
676 clear_bit(GLF_PENDING_DEMOTE, &gl->gl_flags);
677 set_bit(GLF_DEMOTE, &gl->gl_flags);
678 }
679 }
680 run_queue(gl, 0);
681 spin_unlock(&gl->gl_spin);
682 if (!delay)
683 gfs2_glock_put(gl);
684 else {
685 if (gl->gl_name.ln_type != LM_TYPE_INODE)
686 delay = 0;
687 if (queue_delayed_work(glock_workqueue, &gl->gl_work, delay) == 0)
688 gfs2_glock_put(gl);
689 }
690 if (drop_ref)
691 gfs2_glock_put(gl);
692 }
693
694 /**
695 * gfs2_glock_get() - Get a glock, or create one if one doesn't exist
696 * @sdp: The GFS2 superblock
697 * @number: the lock number
698 * @glops: The glock_operations to use
699 * @create: If 0, don't create the glock if it doesn't exist
700 * @glp: the glock is returned here
701 *
702 * This does not lock a glock, just finds/creates structures for one.
703 *
704 * Returns: errno
705 */
706
707 int gfs2_glock_get(struct gfs2_sbd *sdp, u64 number,
708 const struct gfs2_glock_operations *glops, int create,
709 struct gfs2_glock **glp)
710 {
711 struct super_block *s = sdp->sd_vfs;
712 struct lm_lockname name = { .ln_number = number, .ln_type = glops->go_type };
713 struct gfs2_glock *gl, *tmp;
714 unsigned int hash = gl_hash(sdp, &name);
715 struct address_space *mapping;
716 struct kmem_cache *cachep;
717
718 rcu_read_lock();
719 gl = search_bucket(hash, sdp, &name);
720 rcu_read_unlock();
721
722 *glp = gl;
723 if (gl)
724 return 0;
725 if (!create)
726 return -ENOENT;
727
728 if (glops->go_flags & GLOF_ASPACE)
729 cachep = gfs2_glock_aspace_cachep;
730 else
731 cachep = gfs2_glock_cachep;
732 gl = kmem_cache_alloc(cachep, GFP_KERNEL);
733 if (!gl)
734 return -ENOMEM;
735
736 memset(&gl->gl_lksb, 0, sizeof(struct dlm_lksb));
737
738 if (glops->go_flags & GLOF_LVB) {
739 gl->gl_lksb.sb_lvbptr = kzalloc(GFS2_MIN_LVB_SIZE, GFP_KERNEL);
740 if (!gl->gl_lksb.sb_lvbptr) {
741 kmem_cache_free(cachep, gl);
742 return -ENOMEM;
743 }
744 }
745
746 atomic_inc(&sdp->sd_glock_disposal);
747 gl->gl_sbd = sdp;
748 gl->gl_flags = 0;
749 gl->gl_name = name;
750 gl->gl_lockref.count = 1;
751 gl->gl_state = LM_ST_UNLOCKED;
752 gl->gl_target = LM_ST_UNLOCKED;
753 gl->gl_demote_state = LM_ST_EXCLUSIVE;
754 gl->gl_hash = hash;
755 gl->gl_ops = glops;
756 gl->gl_dstamp = ktime_set(0, 0);
757 preempt_disable();
758 /* We use the global stats to estimate the initial per-glock stats */
759 gl->gl_stats = this_cpu_ptr(sdp->sd_lkstats)->lkstats[glops->go_type];
760 preempt_enable();
761 gl->gl_stats.stats[GFS2_LKS_DCOUNT] = 0;
762 gl->gl_stats.stats[GFS2_LKS_QCOUNT] = 0;
763 gl->gl_tchange = jiffies;
764 gl->gl_object = NULL;
765 gl->gl_hold_time = GL_GLOCK_DFT_HOLD;
766 INIT_DELAYED_WORK(&gl->gl_work, glock_work_func);
767 INIT_WORK(&gl->gl_delete, delete_work_func);
768
769 mapping = gfs2_glock2aspace(gl);
770 if (mapping) {
771 mapping->a_ops = &gfs2_meta_aops;
772 mapping->host = s->s_bdev->bd_inode;
773 mapping->flags = 0;
774 mapping_set_gfp_mask(mapping, GFP_NOFS);
775 mapping->private_data = NULL;
776 mapping->backing_dev_info = s->s_bdi;
777 mapping->writeback_index = 0;
778 }
779
780 spin_lock_bucket(hash);
781 tmp = search_bucket(hash, sdp, &name);
782 if (tmp) {
783 spin_unlock_bucket(hash);
784 kfree(gl->gl_lksb.sb_lvbptr);
785 kmem_cache_free(cachep, gl);
786 atomic_dec(&sdp->sd_glock_disposal);
787 gl = tmp;
788 } else {
789 hlist_bl_add_head_rcu(&gl->gl_list, &gl_hash_table[hash]);
790 spin_unlock_bucket(hash);
791 }
792
793 *glp = gl;
794
795 return 0;
796 }
797
798 /**
799 * gfs2_holder_init - initialize a struct gfs2_holder in the default way
800 * @gl: the glock
801 * @state: the state we're requesting
802 * @flags: the modifier flags
803 * @gh: the holder structure
804 *
805 */
806
807 void gfs2_holder_init(struct gfs2_glock *gl, unsigned int state, unsigned flags,
808 struct gfs2_holder *gh)
809 {
810 INIT_LIST_HEAD(&gh->gh_list);
811 gh->gh_gl = gl;
812 gh->gh_ip = (unsigned long)__builtin_return_address(0);
813 gh->gh_owner_pid = get_pid(task_pid(current));
814 gh->gh_state = state;
815 gh->gh_flags = flags;
816 gh->gh_error = 0;
817 gh->gh_iflags = 0;
818 gfs2_glock_hold(gl);
819 }
820
821 /**
822 * gfs2_holder_reinit - reinitialize a struct gfs2_holder so we can requeue it
823 * @state: the state we're requesting
824 * @flags: the modifier flags
825 * @gh: the holder structure
826 *
827 * Don't mess with the glock.
828 *
829 */
830
831 void gfs2_holder_reinit(unsigned int state, unsigned flags, struct gfs2_holder *gh)
832 {
833 gh->gh_state = state;
834 gh->gh_flags = flags;
835 gh->gh_iflags = 0;
836 gh->gh_ip = (unsigned long)__builtin_return_address(0);
837 if (gh->gh_owner_pid)
838 put_pid(gh->gh_owner_pid);
839 gh->gh_owner_pid = get_pid(task_pid(current));
840 }
841
842 /**
843 * gfs2_holder_uninit - uninitialize a holder structure (drop glock reference)
844 * @gh: the holder structure
845 *
846 */
847
848 void gfs2_holder_uninit(struct gfs2_holder *gh)
849 {
850 put_pid(gh->gh_owner_pid);
851 gfs2_glock_put(gh->gh_gl);
852 gh->gh_gl = NULL;
853 gh->gh_ip = 0;
854 }
855
856 /**
857 * gfs2_glock_holder_wait
858 * @word: unused
859 *
860 * This function and gfs2_glock_demote_wait both show up in the WCHAN
861 * field. Thus I've separated these otherwise identical functions in
862 * order to be more informative to the user.
863 */
864
865 static int gfs2_glock_holder_wait(void *word)
866 {
867 schedule();
868 return 0;
869 }
870
871 static int gfs2_glock_demote_wait(void *word)
872 {
873 schedule();
874 return 0;
875 }
876
877 /**
878 * gfs2_glock_wait - wait on a glock acquisition
879 * @gh: the glock holder
880 *
881 * Returns: 0 on success
882 */
883
884 int gfs2_glock_wait(struct gfs2_holder *gh)
885 {
886 unsigned long time1 = jiffies;
887
888 might_sleep();
889 wait_on_bit(&gh->gh_iflags, HIF_WAIT, gfs2_glock_holder_wait, TASK_UNINTERRUPTIBLE);
890 if (time_after(jiffies, time1 + HZ)) /* have we waited > a second? */
891 /* Lengthen the minimum hold time. */
892 gh->gh_gl->gl_hold_time = min(gh->gh_gl->gl_hold_time +
893 GL_GLOCK_HOLD_INCR,
894 GL_GLOCK_MAX_HOLD);
895 return gh->gh_error;
896 }
897
898 /**
899 * handle_callback - process a demote request
900 * @gl: the glock
901 * @state: the state the caller wants us to change to
902 *
903 * There are only two requests that we are going to see in actual
904 * practise: LM_ST_SHARED and LM_ST_UNLOCKED
905 */
906
907 static void handle_callback(struct gfs2_glock *gl, unsigned int state,
908 unsigned long delay, bool remote)
909 {
910 int bit = delay ? GLF_PENDING_DEMOTE : GLF_DEMOTE;
911
912 set_bit(bit, &gl->gl_flags);
913 if (gl->gl_demote_state == LM_ST_EXCLUSIVE) {
914 gl->gl_demote_state = state;
915 gl->gl_demote_time = jiffies;
916 } else if (gl->gl_demote_state != LM_ST_UNLOCKED &&
917 gl->gl_demote_state != state) {
918 gl->gl_demote_state = LM_ST_UNLOCKED;
919 }
920 if (gl->gl_ops->go_callback)
921 gl->gl_ops->go_callback(gl, remote);
922 trace_gfs2_demote_rq(gl, remote);
923 }
924
925 void gfs2_print_dbg(struct seq_file *seq, const char *fmt, ...)
926 {
927 struct va_format vaf;
928 va_list args;
929
930 va_start(args, fmt);
931
932 if (seq) {
933 seq_vprintf(seq, fmt, args);
934 } else {
935 vaf.fmt = fmt;
936 vaf.va = &args;
937
938 printk(KERN_ERR " %pV", &vaf);
939 }
940
941 va_end(args);
942 }
943
944 /**
945 * add_to_queue - Add a holder to the wait queue (but look for recursion)
946 * @gh: the holder structure to add
947 *
948 * Eventually we should move the recursive locking trap to a
949 * debugging option or something like that. This is the fast
950 * path and needs to have the minimum number of distractions.
951 *
952 */
953
954 static inline void add_to_queue(struct gfs2_holder *gh)
955 __releases(&gl->gl_spin)
956 __acquires(&gl->gl_spin)
957 {
958 struct gfs2_glock *gl = gh->gh_gl;
959 struct gfs2_sbd *sdp = gl->gl_sbd;
960 struct list_head *insert_pt = NULL;
961 struct gfs2_holder *gh2;
962 int try_futile = 0;
963
964 BUG_ON(gh->gh_owner_pid == NULL);
965 if (test_and_set_bit(HIF_WAIT, &gh->gh_iflags))
966 BUG();
967
968 if (gh->gh_flags & (LM_FLAG_TRY | LM_FLAG_TRY_1CB)) {
969 if (test_bit(GLF_LOCK, &gl->gl_flags))
970 try_futile = !may_grant(gl, gh);
971 if (test_bit(GLF_INVALIDATE_IN_PROGRESS, &gl->gl_flags))
972 goto fail;
973 }
974
975 list_for_each_entry(gh2, &gl->gl_holders, gh_list) {
976 if (unlikely(gh2->gh_owner_pid == gh->gh_owner_pid &&
977 (gh->gh_gl->gl_ops->go_type != LM_TYPE_FLOCK)))
978 goto trap_recursive;
979 if (try_futile &&
980 !(gh2->gh_flags & (LM_FLAG_TRY | LM_FLAG_TRY_1CB))) {
981 fail:
982 gh->gh_error = GLR_TRYFAILED;
983 gfs2_holder_wake(gh);
984 return;
985 }
986 if (test_bit(HIF_HOLDER, &gh2->gh_iflags))
987 continue;
988 if (unlikely((gh->gh_flags & LM_FLAG_PRIORITY) && !insert_pt))
989 insert_pt = &gh2->gh_list;
990 }
991 set_bit(GLF_QUEUED, &gl->gl_flags);
992 trace_gfs2_glock_queue(gh, 1);
993 gfs2_glstats_inc(gl, GFS2_LKS_QCOUNT);
994 gfs2_sbstats_inc(gl, GFS2_LKS_QCOUNT);
995 if (likely(insert_pt == NULL)) {
996 list_add_tail(&gh->gh_list, &gl->gl_holders);
997 if (unlikely(gh->gh_flags & LM_FLAG_PRIORITY))
998 goto do_cancel;
999 return;
1000 }
1001 list_add_tail(&gh->gh_list, insert_pt);
1002 do_cancel:
1003 gh = list_entry(gl->gl_holders.next, struct gfs2_holder, gh_list);
1004 if (!(gh->gh_flags & LM_FLAG_PRIORITY)) {
1005 spin_unlock(&gl->gl_spin);
1006 if (sdp->sd_lockstruct.ls_ops->lm_cancel)
1007 sdp->sd_lockstruct.ls_ops->lm_cancel(gl);
1008 spin_lock(&gl->gl_spin);
1009 }
1010 return;
1011
1012 trap_recursive:
1013 printk(KERN_ERR "original: %pSR\n", (void *)gh2->gh_ip);
1014 printk(KERN_ERR "pid: %d\n", pid_nr(gh2->gh_owner_pid));
1015 printk(KERN_ERR "lock type: %d req lock state : %d\n",
1016 gh2->gh_gl->gl_name.ln_type, gh2->gh_state);
1017 printk(KERN_ERR "new: %pSR\n", (void *)gh->gh_ip);
1018 printk(KERN_ERR "pid: %d\n", pid_nr(gh->gh_owner_pid));
1019 printk(KERN_ERR "lock type: %d req lock state : %d\n",
1020 gh->gh_gl->gl_name.ln_type, gh->gh_state);
1021 gfs2_dump_glock(NULL, gl);
1022 BUG();
1023 }
1024
1025 /**
1026 * gfs2_glock_nq - enqueue a struct gfs2_holder onto a glock (acquire a glock)
1027 * @gh: the holder structure
1028 *
1029 * if (gh->gh_flags & GL_ASYNC), this never returns an error
1030 *
1031 * Returns: 0, GLR_TRYFAILED, or errno on failure
1032 */
1033
1034 int gfs2_glock_nq(struct gfs2_holder *gh)
1035 {
1036 struct gfs2_glock *gl = gh->gh_gl;
1037 struct gfs2_sbd *sdp = gl->gl_sbd;
1038 int error = 0;
1039
1040 if (unlikely(test_bit(SDF_SHUTDOWN, &sdp->sd_flags)))
1041 return -EIO;
1042
1043 if (test_bit(GLF_LRU, &gl->gl_flags))
1044 gfs2_glock_remove_from_lru(gl);
1045
1046 spin_lock(&gl->gl_spin);
1047 add_to_queue(gh);
1048 if ((LM_FLAG_NOEXP & gh->gh_flags) &&
1049 test_and_clear_bit(GLF_FROZEN, &gl->gl_flags))
1050 set_bit(GLF_REPLY_PENDING, &gl->gl_flags);
1051 run_queue(gl, 1);
1052 spin_unlock(&gl->gl_spin);
1053
1054 if (!(gh->gh_flags & GL_ASYNC))
1055 error = gfs2_glock_wait(gh);
1056
1057 return error;
1058 }
1059
1060 /**
1061 * gfs2_glock_poll - poll to see if an async request has been completed
1062 * @gh: the holder
1063 *
1064 * Returns: 1 if the request is ready to be gfs2_glock_wait()ed on
1065 */
1066
1067 int gfs2_glock_poll(struct gfs2_holder *gh)
1068 {
1069 return test_bit(HIF_WAIT, &gh->gh_iflags) ? 0 : 1;
1070 }
1071
1072 /**
1073 * gfs2_glock_dq - dequeue a struct gfs2_holder from a glock (release a glock)
1074 * @gh: the glock holder
1075 *
1076 */
1077
1078 void gfs2_glock_dq(struct gfs2_holder *gh)
1079 {
1080 struct gfs2_glock *gl = gh->gh_gl;
1081 const struct gfs2_glock_operations *glops = gl->gl_ops;
1082 unsigned delay = 0;
1083 int fast_path = 0;
1084
1085 spin_lock(&gl->gl_spin);
1086 if (gh->gh_flags & GL_NOCACHE)
1087 handle_callback(gl, LM_ST_UNLOCKED, 0, false);
1088
1089 list_del_init(&gh->gh_list);
1090 if (find_first_holder(gl) == NULL) {
1091 if (glops->go_unlock) {
1092 GLOCK_BUG_ON(gl, test_and_set_bit(GLF_LOCK, &gl->gl_flags));
1093 spin_unlock(&gl->gl_spin);
1094 glops->go_unlock(gh);
1095 spin_lock(&gl->gl_spin);
1096 clear_bit(GLF_LOCK, &gl->gl_flags);
1097 }
1098 if (list_empty(&gl->gl_holders) &&
1099 !test_bit(GLF_PENDING_DEMOTE, &gl->gl_flags) &&
1100 !test_bit(GLF_DEMOTE, &gl->gl_flags))
1101 fast_path = 1;
1102 }
1103 if (!test_bit(GLF_LFLUSH, &gl->gl_flags) && demote_ok(gl))
1104 gfs2_glock_add_to_lru(gl);
1105
1106 trace_gfs2_glock_queue(gh, 0);
1107 spin_unlock(&gl->gl_spin);
1108 if (likely(fast_path))
1109 return;
1110
1111 gfs2_glock_hold(gl);
1112 if (test_bit(GLF_PENDING_DEMOTE, &gl->gl_flags) &&
1113 !test_bit(GLF_DEMOTE, &gl->gl_flags) &&
1114 gl->gl_name.ln_type == LM_TYPE_INODE)
1115 delay = gl->gl_hold_time;
1116 if (queue_delayed_work(glock_workqueue, &gl->gl_work, delay) == 0)
1117 gfs2_glock_put(gl);
1118 }
1119
1120 void gfs2_glock_dq_wait(struct gfs2_holder *gh)
1121 {
1122 struct gfs2_glock *gl = gh->gh_gl;
1123 gfs2_glock_dq(gh);
1124 might_sleep();
1125 wait_on_bit(&gl->gl_flags, GLF_DEMOTE, gfs2_glock_demote_wait, TASK_UNINTERRUPTIBLE);
1126 }
1127
1128 /**
1129 * gfs2_glock_dq_uninit - dequeue a holder from a glock and initialize it
1130 * @gh: the holder structure
1131 *
1132 */
1133
1134 void gfs2_glock_dq_uninit(struct gfs2_holder *gh)
1135 {
1136 gfs2_glock_dq(gh);
1137 gfs2_holder_uninit(gh);
1138 }
1139
1140 /**
1141 * gfs2_glock_nq_num - acquire a glock based on lock number
1142 * @sdp: the filesystem
1143 * @number: the lock number
1144 * @glops: the glock operations for the type of glock
1145 * @state: the state to acquire the glock in
1146 * @flags: modifier flags for the acquisition
1147 * @gh: the struct gfs2_holder
1148 *
1149 * Returns: errno
1150 */
1151
1152 int gfs2_glock_nq_num(struct gfs2_sbd *sdp, u64 number,
1153 const struct gfs2_glock_operations *glops,
1154 unsigned int state, int flags, struct gfs2_holder *gh)
1155 {
1156 struct gfs2_glock *gl;
1157 int error;
1158
1159 error = gfs2_glock_get(sdp, number, glops, CREATE, &gl);
1160 if (!error) {
1161 error = gfs2_glock_nq_init(gl, state, flags, gh);
1162 gfs2_glock_put(gl);
1163 }
1164
1165 return error;
1166 }
1167
1168 /**
1169 * glock_compare - Compare two struct gfs2_glock structures for sorting
1170 * @arg_a: the first structure
1171 * @arg_b: the second structure
1172 *
1173 */
1174
1175 static int glock_compare(const void *arg_a, const void *arg_b)
1176 {
1177 const struct gfs2_holder *gh_a = *(const struct gfs2_holder **)arg_a;
1178 const struct gfs2_holder *gh_b = *(const struct gfs2_holder **)arg_b;
1179 const struct lm_lockname *a = &gh_a->gh_gl->gl_name;
1180 const struct lm_lockname *b = &gh_b->gh_gl->gl_name;
1181
1182 if (a->ln_number > b->ln_number)
1183 return 1;
1184 if (a->ln_number < b->ln_number)
1185 return -1;
1186 BUG_ON(gh_a->gh_gl->gl_ops->go_type == gh_b->gh_gl->gl_ops->go_type);
1187 return 0;
1188 }
1189
1190 /**
1191 * nq_m_sync - synchonously acquire more than one glock in deadlock free order
1192 * @num_gh: the number of structures
1193 * @ghs: an array of struct gfs2_holder structures
1194 *
1195 * Returns: 0 on success (all glocks acquired),
1196 * errno on failure (no glocks acquired)
1197 */
1198
1199 static int nq_m_sync(unsigned int num_gh, struct gfs2_holder *ghs,
1200 struct gfs2_holder **p)
1201 {
1202 unsigned int x;
1203 int error = 0;
1204
1205 for (x = 0; x < num_gh; x++)
1206 p[x] = &ghs[x];
1207
1208 sort(p, num_gh, sizeof(struct gfs2_holder *), glock_compare, NULL);
1209
1210 for (x = 0; x < num_gh; x++) {
1211 p[x]->gh_flags &= ~(LM_FLAG_TRY | GL_ASYNC);
1212
1213 error = gfs2_glock_nq(p[x]);
1214 if (error) {
1215 while (x--)
1216 gfs2_glock_dq(p[x]);
1217 break;
1218 }
1219 }
1220
1221 return error;
1222 }
1223
1224 /**
1225 * gfs2_glock_nq_m - acquire multiple glocks
1226 * @num_gh: the number of structures
1227 * @ghs: an array of struct gfs2_holder structures
1228 *
1229 *
1230 * Returns: 0 on success (all glocks acquired),
1231 * errno on failure (no glocks acquired)
1232 */
1233
1234 int gfs2_glock_nq_m(unsigned int num_gh, struct gfs2_holder *ghs)
1235 {
1236 struct gfs2_holder *tmp[4];
1237 struct gfs2_holder **pph = tmp;
1238 int error = 0;
1239
1240 switch(num_gh) {
1241 case 0:
1242 return 0;
1243 case 1:
1244 ghs->gh_flags &= ~(LM_FLAG_TRY | GL_ASYNC);
1245 return gfs2_glock_nq(ghs);
1246 default:
1247 if (num_gh <= 4)
1248 break;
1249 pph = kmalloc(num_gh * sizeof(struct gfs2_holder *), GFP_NOFS);
1250 if (!pph)
1251 return -ENOMEM;
1252 }
1253
1254 error = nq_m_sync(num_gh, ghs, pph);
1255
1256 if (pph != tmp)
1257 kfree(pph);
1258
1259 return error;
1260 }
1261
1262 /**
1263 * gfs2_glock_dq_m - release multiple glocks
1264 * @num_gh: the number of structures
1265 * @ghs: an array of struct gfs2_holder structures
1266 *
1267 */
1268
1269 void gfs2_glock_dq_m(unsigned int num_gh, struct gfs2_holder *ghs)
1270 {
1271 while (num_gh--)
1272 gfs2_glock_dq(&ghs[num_gh]);
1273 }
1274
1275 void gfs2_glock_cb(struct gfs2_glock *gl, unsigned int state)
1276 {
1277 unsigned long delay = 0;
1278 unsigned long holdtime;
1279 unsigned long now = jiffies;
1280
1281 gfs2_glock_hold(gl);
1282 holdtime = gl->gl_tchange + gl->gl_hold_time;
1283 if (test_bit(GLF_QUEUED, &gl->gl_flags) &&
1284 gl->gl_name.ln_type == LM_TYPE_INODE) {
1285 if (time_before(now, holdtime))
1286 delay = holdtime - now;
1287 if (test_bit(GLF_REPLY_PENDING, &gl->gl_flags))
1288 delay = gl->gl_hold_time;
1289 }
1290
1291 spin_lock(&gl->gl_spin);
1292 handle_callback(gl, state, delay, true);
1293 spin_unlock(&gl->gl_spin);
1294 if (queue_delayed_work(glock_workqueue, &gl->gl_work, delay) == 0)
1295 gfs2_glock_put(gl);
1296 }
1297
1298 /**
1299 * gfs2_should_freeze - Figure out if glock should be frozen
1300 * @gl: The glock in question
1301 *
1302 * Glocks are not frozen if (a) the result of the dlm operation is
1303 * an error, (b) the locking operation was an unlock operation or
1304 * (c) if there is a "noexp" flagged request anywhere in the queue
1305 *
1306 * Returns: 1 if freezing should occur, 0 otherwise
1307 */
1308
1309 static int gfs2_should_freeze(const struct gfs2_glock *gl)
1310 {
1311 const struct gfs2_holder *gh;
1312
1313 if (gl->gl_reply & ~LM_OUT_ST_MASK)
1314 return 0;
1315 if (gl->gl_target == LM_ST_UNLOCKED)
1316 return 0;
1317
1318 list_for_each_entry(gh, &gl->gl_holders, gh_list) {
1319 if (test_bit(HIF_HOLDER, &gh->gh_iflags))
1320 continue;
1321 if (LM_FLAG_NOEXP & gh->gh_flags)
1322 return 0;
1323 }
1324
1325 return 1;
1326 }
1327
1328 /**
1329 * gfs2_glock_complete - Callback used by locking
1330 * @gl: Pointer to the glock
1331 * @ret: The return value from the dlm
1332 *
1333 * The gl_reply field is under the gl_spin lock so that it is ok
1334 * to use a bitfield shared with other glock state fields.
1335 */
1336
1337 void gfs2_glock_complete(struct gfs2_glock *gl, int ret)
1338 {
1339 struct lm_lockstruct *ls = &gl->gl_sbd->sd_lockstruct;
1340
1341 spin_lock(&gl->gl_spin);
1342 gl->gl_reply = ret;
1343
1344 if (unlikely(test_bit(DFL_BLOCK_LOCKS, &ls->ls_recover_flags))) {
1345 if (gfs2_should_freeze(gl)) {
1346 set_bit(GLF_FROZEN, &gl->gl_flags);
1347 spin_unlock(&gl->gl_spin);
1348 return;
1349 }
1350 }
1351
1352 gl->gl_lockref.count++;
1353 set_bit(GLF_REPLY_PENDING, &gl->gl_flags);
1354 spin_unlock(&gl->gl_spin);
1355
1356 if (queue_delayed_work(glock_workqueue, &gl->gl_work, 0) == 0)
1357 gfs2_glock_put(gl);
1358 }
1359
1360 static int glock_cmp(void *priv, struct list_head *a, struct list_head *b)
1361 {
1362 struct gfs2_glock *gla, *glb;
1363
1364 gla = list_entry(a, struct gfs2_glock, gl_lru);
1365 glb = list_entry(b, struct gfs2_glock, gl_lru);
1366
1367 if (gla->gl_name.ln_number > glb->gl_name.ln_number)
1368 return 1;
1369 if (gla->gl_name.ln_number < glb->gl_name.ln_number)
1370 return -1;
1371
1372 return 0;
1373 }
1374
1375 /**
1376 * gfs2_dispose_glock_lru - Demote a list of glocks
1377 * @list: The list to dispose of
1378 *
1379 * Disposing of glocks may involve disk accesses, so that here we sort
1380 * the glocks by number (i.e. disk location of the inodes) so that if
1381 * there are any such accesses, they'll be sent in order (mostly).
1382 *
1383 * Must be called under the lru_lock, but may drop and retake this
1384 * lock. While the lru_lock is dropped, entries may vanish from the
1385 * list, but no new entries will appear on the list (since it is
1386 * private)
1387 */
1388
1389 static void gfs2_dispose_glock_lru(struct list_head *list)
1390 __releases(&lru_lock)
1391 __acquires(&lru_lock)
1392 {
1393 struct gfs2_glock *gl;
1394
1395 list_sort(NULL, list, glock_cmp);
1396
1397 while(!list_empty(list)) {
1398 gl = list_entry(list->next, struct gfs2_glock, gl_lru);
1399 list_del_init(&gl->gl_lru);
1400 if (!spin_trylock(&gl->gl_spin)) {
1401 list_add(&gl->gl_lru, &lru_list);
1402 atomic_inc(&lru_count);
1403 continue;
1404 }
1405 clear_bit(GLF_LRU, &gl->gl_flags);
1406 spin_unlock(&lru_lock);
1407 gl->gl_lockref.count++;
1408 if (demote_ok(gl))
1409 handle_callback(gl, LM_ST_UNLOCKED, 0, false);
1410 WARN_ON(!test_and_clear_bit(GLF_LOCK, &gl->gl_flags));
1411 if (queue_delayed_work(glock_workqueue, &gl->gl_work, 0) == 0)
1412 gl->gl_lockref.count--;
1413 spin_unlock(&gl->gl_spin);
1414 spin_lock(&lru_lock);
1415 }
1416 }
1417
1418 /**
1419 * gfs2_scan_glock_lru - Scan the LRU looking for locks to demote
1420 * @nr: The number of entries to scan
1421 *
1422 * This function selects the entries on the LRU which are able to
1423 * be demoted, and then kicks off the process by calling
1424 * gfs2_dispose_glock_lru() above.
1425 */
1426
1427 static long gfs2_scan_glock_lru(int nr)
1428 {
1429 struct gfs2_glock *gl;
1430 LIST_HEAD(skipped);
1431 LIST_HEAD(dispose);
1432 long freed = 0;
1433
1434 spin_lock(&lru_lock);
1435 while ((nr-- >= 0) && !list_empty(&lru_list)) {
1436 gl = list_entry(lru_list.next, struct gfs2_glock, gl_lru);
1437
1438 /* Test for being demotable */
1439 if (!test_and_set_bit(GLF_LOCK, &gl->gl_flags)) {
1440 list_move(&gl->gl_lru, &dispose);
1441 atomic_dec(&lru_count);
1442 freed++;
1443 continue;
1444 }
1445
1446 list_move(&gl->gl_lru, &skipped);
1447 }
1448 list_splice(&skipped, &lru_list);
1449 if (!list_empty(&dispose))
1450 gfs2_dispose_glock_lru(&dispose);
1451 spin_unlock(&lru_lock);
1452
1453 return freed;
1454 }
1455
1456 static unsigned long gfs2_glock_shrink_scan(struct shrinker *shrink,
1457 struct shrink_control *sc)
1458 {
1459 if (!(sc->gfp_mask & __GFP_FS))
1460 return SHRINK_STOP;
1461 return gfs2_scan_glock_lru(sc->nr_to_scan);
1462 }
1463
1464 static unsigned long gfs2_glock_shrink_count(struct shrinker *shrink,
1465 struct shrink_control *sc)
1466 {
1467 return vfs_pressure_ratio(atomic_read(&lru_count));
1468 }
1469
1470 static struct shrinker glock_shrinker = {
1471 .seeks = DEFAULT_SEEKS,
1472 .count_objects = gfs2_glock_shrink_count,
1473 .scan_objects = gfs2_glock_shrink_scan,
1474 };
1475
1476 /**
1477 * examine_bucket - Call a function for glock in a hash bucket
1478 * @examiner: the function
1479 * @sdp: the filesystem
1480 * @bucket: the bucket
1481 *
1482 */
1483
1484 static void examine_bucket(glock_examiner examiner, const struct gfs2_sbd *sdp,
1485 unsigned int hash)
1486 {
1487 struct gfs2_glock *gl;
1488 struct hlist_bl_head *head = &gl_hash_table[hash];
1489 struct hlist_bl_node *pos;
1490
1491 rcu_read_lock();
1492 hlist_bl_for_each_entry_rcu(gl, pos, head, gl_list) {
1493 if ((gl->gl_sbd == sdp) && lockref_get_not_dead(&gl->gl_lockref))
1494 examiner(gl);
1495 }
1496 rcu_read_unlock();
1497 cond_resched();
1498 }
1499
1500 static void glock_hash_walk(glock_examiner examiner, const struct gfs2_sbd *sdp)
1501 {
1502 unsigned x;
1503
1504 for (x = 0; x < GFS2_GL_HASH_SIZE; x++)
1505 examine_bucket(examiner, sdp, x);
1506 }
1507
1508
1509 /**
1510 * thaw_glock - thaw out a glock which has an unprocessed reply waiting
1511 * @gl: The glock to thaw
1512 *
1513 */
1514
1515 static void thaw_glock(struct gfs2_glock *gl)
1516 {
1517 if (!test_and_clear_bit(GLF_FROZEN, &gl->gl_flags))
1518 goto out;
1519 set_bit(GLF_REPLY_PENDING, &gl->gl_flags);
1520 if (queue_delayed_work(glock_workqueue, &gl->gl_work, 0) == 0) {
1521 out:
1522 gfs2_glock_put(gl);
1523 }
1524 }
1525
1526 /**
1527 * clear_glock - look at a glock and see if we can free it from glock cache
1528 * @gl: the glock to look at
1529 *
1530 */
1531
1532 static void clear_glock(struct gfs2_glock *gl)
1533 {
1534 gfs2_glock_remove_from_lru(gl);
1535
1536 spin_lock(&gl->gl_spin);
1537 if (gl->gl_state != LM_ST_UNLOCKED)
1538 handle_callback(gl, LM_ST_UNLOCKED, 0, false);
1539 spin_unlock(&gl->gl_spin);
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 void dump_glock(struct seq_file *seq, struct gfs2_glock *gl)
1556 {
1557 spin_lock(&gl->gl_spin);
1558 gfs2_dump_glock(seq, gl);
1559 spin_unlock(&gl->gl_spin);
1560 }
1561
1562 static void dump_glock_func(struct gfs2_glock *gl)
1563 {
1564 dump_glock(NULL, gl);
1565 }
1566
1567 /**
1568 * gfs2_gl_hash_clear - Empty out the glock hash table
1569 * @sdp: the filesystem
1570 * @wait: wait until it's all gone
1571 *
1572 * Called when unmounting the filesystem.
1573 */
1574
1575 void gfs2_gl_hash_clear(struct gfs2_sbd *sdp)
1576 {
1577 set_bit(SDF_SKIP_DLM_UNLOCK, &sdp->sd_flags);
1578 flush_workqueue(glock_workqueue);
1579 glock_hash_walk(clear_glock, sdp);
1580 flush_workqueue(glock_workqueue);
1581 wait_event(sdp->sd_glock_wait, atomic_read(&sdp->sd_glock_disposal) == 0);
1582 glock_hash_walk(dump_glock_func, sdp);
1583 }
1584
1585 void gfs2_glock_finish_truncate(struct gfs2_inode *ip)
1586 {
1587 struct gfs2_glock *gl = ip->i_gl;
1588 int ret;
1589
1590 ret = gfs2_truncatei_resume(ip);
1591 gfs2_assert_withdraw(gl->gl_sbd, ret == 0);
1592
1593 spin_lock(&gl->gl_spin);
1594 clear_bit(GLF_LOCK, &gl->gl_flags);
1595 run_queue(gl, 1);
1596 spin_unlock(&gl->gl_spin);
1597 }
1598
1599 static const char *state2str(unsigned state)
1600 {
1601 switch(state) {
1602 case LM_ST_UNLOCKED:
1603 return "UN";
1604 case LM_ST_SHARED:
1605 return "SH";
1606 case LM_ST_DEFERRED:
1607 return "DF";
1608 case LM_ST_EXCLUSIVE:
1609 return "EX";
1610 }
1611 return "??";
1612 }
1613
1614 static const char *hflags2str(char *buf, unsigned flags, unsigned long iflags)
1615 {
1616 char *p = buf;
1617 if (flags & LM_FLAG_TRY)
1618 *p++ = 't';
1619 if (flags & LM_FLAG_TRY_1CB)
1620 *p++ = 'T';
1621 if (flags & LM_FLAG_NOEXP)
1622 *p++ = 'e';
1623 if (flags & LM_FLAG_ANY)
1624 *p++ = 'A';
1625 if (flags & LM_FLAG_PRIORITY)
1626 *p++ = 'p';
1627 if (flags & GL_ASYNC)
1628 *p++ = 'a';
1629 if (flags & GL_EXACT)
1630 *p++ = 'E';
1631 if (flags & GL_NOCACHE)
1632 *p++ = 'c';
1633 if (test_bit(HIF_HOLDER, &iflags))
1634 *p++ = 'H';
1635 if (test_bit(HIF_WAIT, &iflags))
1636 *p++ = 'W';
1637 if (test_bit(HIF_FIRST, &iflags))
1638 *p++ = 'F';
1639 *p = 0;
1640 return buf;
1641 }
1642
1643 /**
1644 * dump_holder - print information about a glock holder
1645 * @seq: the seq_file struct
1646 * @gh: the glock holder
1647 *
1648 */
1649
1650 static void dump_holder(struct seq_file *seq, const struct gfs2_holder *gh)
1651 {
1652 struct task_struct *gh_owner = NULL;
1653 char flags_buf[32];
1654
1655 rcu_read_lock();
1656 if (gh->gh_owner_pid)
1657 gh_owner = pid_task(gh->gh_owner_pid, PIDTYPE_PID);
1658 gfs2_print_dbg(seq, " H: s:%s f:%s e:%d p:%ld [%s] %pS\n",
1659 state2str(gh->gh_state),
1660 hflags2str(flags_buf, gh->gh_flags, gh->gh_iflags),
1661 gh->gh_error,
1662 gh->gh_owner_pid ? (long)pid_nr(gh->gh_owner_pid) : -1,
1663 gh_owner ? gh_owner->comm : "(ended)",
1664 (void *)gh->gh_ip);
1665 rcu_read_unlock();
1666 }
1667
1668 static const char *gflags2str(char *buf, const struct gfs2_glock *gl)
1669 {
1670 const unsigned long *gflags = &gl->gl_flags;
1671 char *p = buf;
1672
1673 if (test_bit(GLF_LOCK, gflags))
1674 *p++ = 'l';
1675 if (test_bit(GLF_DEMOTE, gflags))
1676 *p++ = 'D';
1677 if (test_bit(GLF_PENDING_DEMOTE, gflags))
1678 *p++ = 'd';
1679 if (test_bit(GLF_DEMOTE_IN_PROGRESS, gflags))
1680 *p++ = 'p';
1681 if (test_bit(GLF_DIRTY, gflags))
1682 *p++ = 'y';
1683 if (test_bit(GLF_LFLUSH, gflags))
1684 *p++ = 'f';
1685 if (test_bit(GLF_INVALIDATE_IN_PROGRESS, gflags))
1686 *p++ = 'i';
1687 if (test_bit(GLF_REPLY_PENDING, gflags))
1688 *p++ = 'r';
1689 if (test_bit(GLF_INITIAL, gflags))
1690 *p++ = 'I';
1691 if (test_bit(GLF_FROZEN, gflags))
1692 *p++ = 'F';
1693 if (test_bit(GLF_QUEUED, gflags))
1694 *p++ = 'q';
1695 if (test_bit(GLF_LRU, gflags))
1696 *p++ = 'L';
1697 if (gl->gl_object)
1698 *p++ = 'o';
1699 if (test_bit(GLF_BLOCKING, gflags))
1700 *p++ = 'b';
1701 *p = 0;
1702 return buf;
1703 }
1704
1705 /**
1706 * gfs2_dump_glock - print information about a glock
1707 * @seq: The seq_file struct
1708 * @gl: the glock
1709 *
1710 * The file format is as follows:
1711 * One line per object, capital letters are used to indicate objects
1712 * G = glock, I = Inode, R = rgrp, H = holder. Glocks are not indented,
1713 * other objects are indented by a single space and follow the glock to
1714 * which they are related. Fields are indicated by lower case letters
1715 * followed by a colon and the field value, except for strings which are in
1716 * [] so that its possible to see if they are composed of spaces for
1717 * example. The field's are n = number (id of the object), f = flags,
1718 * t = type, s = state, r = refcount, e = error, p = pid.
1719 *
1720 */
1721
1722 void gfs2_dump_glock(struct seq_file *seq, const struct gfs2_glock *gl)
1723 {
1724 const struct gfs2_glock_operations *glops = gl->gl_ops;
1725 unsigned long long dtime;
1726 const struct gfs2_holder *gh;
1727 char gflags_buf[32];
1728
1729 dtime = jiffies - gl->gl_demote_time;
1730 dtime *= 1000000/HZ; /* demote time in uSec */
1731 if (!test_bit(GLF_DEMOTE, &gl->gl_flags))
1732 dtime = 0;
1733 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",
1734 state2str(gl->gl_state),
1735 gl->gl_name.ln_type,
1736 (unsigned long long)gl->gl_name.ln_number,
1737 gflags2str(gflags_buf, gl),
1738 state2str(gl->gl_target),
1739 state2str(gl->gl_demote_state), dtime,
1740 atomic_read(&gl->gl_ail_count),
1741 atomic_read(&gl->gl_revokes),
1742 (int)gl->gl_lockref.count, gl->gl_hold_time);
1743
1744 list_for_each_entry(gh, &gl->gl_holders, gh_list)
1745 dump_holder(seq, gh);
1746
1747 if (gl->gl_state != LM_ST_UNLOCKED && glops->go_dump)
1748 glops->go_dump(seq, gl);
1749 }
1750
1751 static int gfs2_glstats_seq_show(struct seq_file *seq, void *iter_ptr)
1752 {
1753 struct gfs2_glock *gl = iter_ptr;
1754
1755 seq_printf(seq, "G: n:%u/%llx rtt:%lld/%lld rttb:%lld/%lld irt:%lld/%lld dcnt: %lld qcnt: %lld\n",
1756 gl->gl_name.ln_type,
1757 (unsigned long long)gl->gl_name.ln_number,
1758 (long long)gl->gl_stats.stats[GFS2_LKS_SRTT],
1759 (long long)gl->gl_stats.stats[GFS2_LKS_SRTTVAR],
1760 (long long)gl->gl_stats.stats[GFS2_LKS_SRTTB],
1761 (long long)gl->gl_stats.stats[GFS2_LKS_SRTTVARB],
1762 (long long)gl->gl_stats.stats[GFS2_LKS_SIRT],
1763 (long long)gl->gl_stats.stats[GFS2_LKS_SIRTVAR],
1764 (long long)gl->gl_stats.stats[GFS2_LKS_DCOUNT],
1765 (long long)gl->gl_stats.stats[GFS2_LKS_QCOUNT]);
1766 return 0;
1767 }
1768
1769 static const char *gfs2_gltype[] = {
1770 "type",
1771 "reserved",
1772 "nondisk",
1773 "inode",
1774 "rgrp",
1775 "meta",
1776 "iopen",
1777 "flock",
1778 "plock",
1779 "quota",
1780 "journal",
1781 };
1782
1783 static const char *gfs2_stype[] = {
1784 [GFS2_LKS_SRTT] = "srtt",
1785 [GFS2_LKS_SRTTVAR] = "srttvar",
1786 [GFS2_LKS_SRTTB] = "srttb",
1787 [GFS2_LKS_SRTTVARB] = "srttvarb",
1788 [GFS2_LKS_SIRT] = "sirt",
1789 [GFS2_LKS_SIRTVAR] = "sirtvar",
1790 [GFS2_LKS_DCOUNT] = "dlm",
1791 [GFS2_LKS_QCOUNT] = "queue",
1792 };
1793
1794 #define GFS2_NR_SBSTATS (ARRAY_SIZE(gfs2_gltype) * ARRAY_SIZE(gfs2_stype))
1795
1796 static int gfs2_sbstats_seq_show(struct seq_file *seq, void *iter_ptr)
1797 {
1798 struct gfs2_glock_iter *gi = seq->private;
1799 struct gfs2_sbd *sdp = gi->sdp;
1800 unsigned index = gi->hash >> 3;
1801 unsigned subindex = gi->hash & 0x07;
1802 s64 value;
1803 int i;
1804
1805 if (index == 0 && subindex != 0)
1806 return 0;
1807
1808 seq_printf(seq, "%-10s %8s:", gfs2_gltype[index],
1809 (index == 0) ? "cpu": gfs2_stype[subindex]);
1810
1811 for_each_possible_cpu(i) {
1812 const struct gfs2_pcpu_lkstats *lkstats = per_cpu_ptr(sdp->sd_lkstats, i);
1813 if (index == 0) {
1814 value = i;
1815 } else {
1816 value = lkstats->lkstats[index - 1].stats[subindex];
1817 }
1818 seq_printf(seq, " %15lld", (long long)value);
1819 }
1820 seq_putc(seq, '\n');
1821 return 0;
1822 }
1823
1824 int __init gfs2_glock_init(void)
1825 {
1826 unsigned i;
1827 for(i = 0; i < GFS2_GL_HASH_SIZE; i++) {
1828 INIT_HLIST_BL_HEAD(&gl_hash_table[i]);
1829 }
1830
1831 glock_workqueue = alloc_workqueue("glock_workqueue", WQ_MEM_RECLAIM |
1832 WQ_HIGHPRI | WQ_FREEZABLE, 0);
1833 if (!glock_workqueue)
1834 return -ENOMEM;
1835 gfs2_delete_workqueue = alloc_workqueue("delete_workqueue",
1836 WQ_MEM_RECLAIM | WQ_FREEZABLE,
1837 0);
1838 if (!gfs2_delete_workqueue) {
1839 destroy_workqueue(glock_workqueue);
1840 return -ENOMEM;
1841 }
1842
1843 register_shrinker(&glock_shrinker);
1844
1845 return 0;
1846 }
1847
1848 void gfs2_glock_exit(void)
1849 {
1850 unregister_shrinker(&glock_shrinker);
1851 destroy_workqueue(glock_workqueue);
1852 destroy_workqueue(gfs2_delete_workqueue);
1853 }
1854
1855 static inline struct gfs2_glock *glock_hash_chain(unsigned hash)
1856 {
1857 return hlist_bl_entry(hlist_bl_first_rcu(&gl_hash_table[hash]),
1858 struct gfs2_glock, gl_list);
1859 }
1860
1861 static inline struct gfs2_glock *glock_hash_next(struct gfs2_glock *gl)
1862 {
1863 return hlist_bl_entry(rcu_dereference(gl->gl_list.next),
1864 struct gfs2_glock, gl_list);
1865 }
1866
1867 static int gfs2_glock_iter_next(struct gfs2_glock_iter *gi)
1868 {
1869 struct gfs2_glock *gl;
1870
1871 do {
1872 gl = gi->gl;
1873 if (gl) {
1874 gi->gl = glock_hash_next(gl);
1875 gi->nhash++;
1876 } else {
1877 if (gi->hash >= GFS2_GL_HASH_SIZE) {
1878 rcu_read_unlock();
1879 return 1;
1880 }
1881 gi->gl = glock_hash_chain(gi->hash);
1882 gi->nhash = 0;
1883 }
1884 while (gi->gl == NULL) {
1885 gi->hash++;
1886 if (gi->hash >= GFS2_GL_HASH_SIZE) {
1887 rcu_read_unlock();
1888 return 1;
1889 }
1890 gi->gl = glock_hash_chain(gi->hash);
1891 gi->nhash = 0;
1892 }
1893 /* Skip entries for other sb and dead entries */
1894 } while (gi->sdp != gi->gl->gl_sbd ||
1895 __lockref_is_dead(&gi->gl->gl_lockref));
1896
1897 return 0;
1898 }
1899
1900 static void *gfs2_glock_seq_start(struct seq_file *seq, loff_t *pos)
1901 {
1902 struct gfs2_glock_iter *gi = seq->private;
1903 loff_t n = *pos;
1904
1905 if (gi->last_pos <= *pos)
1906 n = gi->nhash + (*pos - gi->last_pos);
1907 else
1908 gi->hash = 0;
1909
1910 gi->nhash = 0;
1911 rcu_read_lock();
1912
1913 do {
1914 if (gfs2_glock_iter_next(gi))
1915 return NULL;
1916 } while (n--);
1917
1918 gi->last_pos = *pos;
1919 return gi->gl;
1920 }
1921
1922 static void *gfs2_glock_seq_next(struct seq_file *seq, void *iter_ptr,
1923 loff_t *pos)
1924 {
1925 struct gfs2_glock_iter *gi = seq->private;
1926
1927 (*pos)++;
1928 gi->last_pos = *pos;
1929 if (gfs2_glock_iter_next(gi))
1930 return NULL;
1931
1932 return gi->gl;
1933 }
1934
1935 static void gfs2_glock_seq_stop(struct seq_file *seq, void *iter_ptr)
1936 {
1937 struct gfs2_glock_iter *gi = seq->private;
1938
1939 if (gi->gl)
1940 rcu_read_unlock();
1941 gi->gl = NULL;
1942 }
1943
1944 static int gfs2_glock_seq_show(struct seq_file *seq, void *iter_ptr)
1945 {
1946 dump_glock(seq, iter_ptr);
1947 return 0;
1948 }
1949
1950 static void *gfs2_sbstats_seq_start(struct seq_file *seq, loff_t *pos)
1951 {
1952 struct gfs2_glock_iter *gi = seq->private;
1953
1954 gi->hash = *pos;
1955 if (*pos >= GFS2_NR_SBSTATS)
1956 return NULL;
1957 preempt_disable();
1958 return SEQ_START_TOKEN;
1959 }
1960
1961 static void *gfs2_sbstats_seq_next(struct seq_file *seq, void *iter_ptr,
1962 loff_t *pos)
1963 {
1964 struct gfs2_glock_iter *gi = seq->private;
1965 (*pos)++;
1966 gi->hash++;
1967 if (gi->hash >= GFS2_NR_SBSTATS) {
1968 preempt_enable();
1969 return NULL;
1970 }
1971 return SEQ_START_TOKEN;
1972 }
1973
1974 static void gfs2_sbstats_seq_stop(struct seq_file *seq, void *iter_ptr)
1975 {
1976 preempt_enable();
1977 }
1978
1979 static const struct seq_operations gfs2_glock_seq_ops = {
1980 .start = gfs2_glock_seq_start,
1981 .next = gfs2_glock_seq_next,
1982 .stop = gfs2_glock_seq_stop,
1983 .show = gfs2_glock_seq_show,
1984 };
1985
1986 static const struct seq_operations gfs2_glstats_seq_ops = {
1987 .start = gfs2_glock_seq_start,
1988 .next = gfs2_glock_seq_next,
1989 .stop = gfs2_glock_seq_stop,
1990 .show = gfs2_glstats_seq_show,
1991 };
1992
1993 static const struct seq_operations gfs2_sbstats_seq_ops = {
1994 .start = gfs2_sbstats_seq_start,
1995 .next = gfs2_sbstats_seq_next,
1996 .stop = gfs2_sbstats_seq_stop,
1997 .show = gfs2_sbstats_seq_show,
1998 };
1999
2000 #define GFS2_SEQ_GOODSIZE min(PAGE_SIZE << PAGE_ALLOC_COSTLY_ORDER, 65536UL)
2001
2002 static int gfs2_glocks_open(struct inode *inode, struct file *file)
2003 {
2004 int ret = seq_open_private(file, &gfs2_glock_seq_ops,
2005 sizeof(struct gfs2_glock_iter));
2006 if (ret == 0) {
2007 struct seq_file *seq = file->private_data;
2008 struct gfs2_glock_iter *gi = seq->private;
2009 gi->sdp = inode->i_private;
2010 seq->buf = kmalloc(GFS2_SEQ_GOODSIZE, GFP_KERNEL | __GFP_NOWARN);
2011 if (seq->buf)
2012 seq->size = GFS2_SEQ_GOODSIZE;
2013 }
2014 return ret;
2015 }
2016
2017 static int gfs2_glstats_open(struct inode *inode, struct file *file)
2018 {
2019 int ret = seq_open_private(file, &gfs2_glstats_seq_ops,
2020 sizeof(struct gfs2_glock_iter));
2021 if (ret == 0) {
2022 struct seq_file *seq = file->private_data;
2023 struct gfs2_glock_iter *gi = seq->private;
2024 gi->sdp = inode->i_private;
2025 seq->buf = kmalloc(GFS2_SEQ_GOODSIZE, GFP_KERNEL | __GFP_NOWARN);
2026 if (seq->buf)
2027 seq->size = GFS2_SEQ_GOODSIZE;
2028 }
2029 return ret;
2030 }
2031
2032 static int gfs2_sbstats_open(struct inode *inode, struct file *file)
2033 {
2034 int ret = seq_open_private(file, &gfs2_sbstats_seq_ops,
2035 sizeof(struct gfs2_glock_iter));
2036 if (ret == 0) {
2037 struct seq_file *seq = file->private_data;
2038 struct gfs2_glock_iter *gi = seq->private;
2039 gi->sdp = inode->i_private;
2040 }
2041 return ret;
2042 }
2043
2044 static const struct file_operations gfs2_glocks_fops = {
2045 .owner = THIS_MODULE,
2046 .open = gfs2_glocks_open,
2047 .read = seq_read,
2048 .llseek = seq_lseek,
2049 .release = seq_release_private,
2050 };
2051
2052 static const struct file_operations gfs2_glstats_fops = {
2053 .owner = THIS_MODULE,
2054 .open = gfs2_glstats_open,
2055 .read = seq_read,
2056 .llseek = seq_lseek,
2057 .release = seq_release_private,
2058 };
2059
2060 static const struct file_operations gfs2_sbstats_fops = {
2061 .owner = THIS_MODULE,
2062 .open = gfs2_sbstats_open,
2063 .read = seq_read,
2064 .llseek = seq_lseek,
2065 .release = seq_release_private,
2066 };
2067
2068 int gfs2_create_debugfs_file(struct gfs2_sbd *sdp)
2069 {
2070 sdp->debugfs_dir = debugfs_create_dir(sdp->sd_table_name, gfs2_root);
2071 if (!sdp->debugfs_dir)
2072 return -ENOMEM;
2073 sdp->debugfs_dentry_glocks = debugfs_create_file("glocks",
2074 S_IFREG | S_IRUGO,
2075 sdp->debugfs_dir, sdp,
2076 &gfs2_glocks_fops);
2077 if (!sdp->debugfs_dentry_glocks)
2078 goto fail;
2079
2080 sdp->debugfs_dentry_glstats = debugfs_create_file("glstats",
2081 S_IFREG | S_IRUGO,
2082 sdp->debugfs_dir, sdp,
2083 &gfs2_glstats_fops);
2084 if (!sdp->debugfs_dentry_glstats)
2085 goto fail;
2086
2087 sdp->debugfs_dentry_sbstats = debugfs_create_file("sbstats",
2088 S_IFREG | S_IRUGO,
2089 sdp->debugfs_dir, sdp,
2090 &gfs2_sbstats_fops);
2091 if (!sdp->debugfs_dentry_sbstats)
2092 goto fail;
2093
2094 return 0;
2095 fail:
2096 gfs2_delete_debugfs_file(sdp);
2097 return -ENOMEM;
2098 }
2099
2100 void gfs2_delete_debugfs_file(struct gfs2_sbd *sdp)
2101 {
2102 if (sdp->debugfs_dir) {
2103 if (sdp->debugfs_dentry_glocks) {
2104 debugfs_remove(sdp->debugfs_dentry_glocks);
2105 sdp->debugfs_dentry_glocks = NULL;
2106 }
2107 if (sdp->debugfs_dentry_glstats) {
2108 debugfs_remove(sdp->debugfs_dentry_glstats);
2109 sdp->debugfs_dentry_glstats = NULL;
2110 }
2111 if (sdp->debugfs_dentry_sbstats) {
2112 debugfs_remove(sdp->debugfs_dentry_sbstats);
2113 sdp->debugfs_dentry_sbstats = NULL;
2114 }
2115 debugfs_remove(sdp->debugfs_dir);
2116 sdp->debugfs_dir = NULL;
2117 }
2118 }
2119
2120 int gfs2_register_debugfs(void)
2121 {
2122 gfs2_root = debugfs_create_dir("gfs2", NULL);
2123 return gfs2_root ? 0 : -ENOMEM;
2124 }
2125
2126 void gfs2_unregister_debugfs(void)
2127 {
2128 debugfs_remove(gfs2_root);
2129 gfs2_root = NULL;
2130 }
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