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fs/exec.c:de_thread: move notify_count write under lock
[linux-2.6/btrfs-unstable.git] / fs / gfs2 / glock.c
blob0fa8062f85a7ab20332301ffafd1733940352096
1 /*
2 * Copyright (C) Sistina Software, Inc. 1997-2003 All rights reserved.
3 * Copyright (C) 2004-2008 Red Hat, Inc. All rights reserved.
4 *
5 * This copyrighted material is made available to anyone wishing to use,
6 * modify, copy, or redistribute it subject to the terms and conditions
7 * of the GNU General Public License version 2.
8 */
9
10 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
11
12 #include <linux/sched.h>
13 #include <linux/slab.h>
14 #include <linux/spinlock.h>
15 #include <linux/buffer_head.h>
16 #include <linux/delay.h>
17 #include <linux/sort.h>
18 #include <linux/jhash.h>
19 #include <linux/kallsyms.h>
20 #include <linux/gfs2_ondisk.h>
21 #include <linux/list.h>
22 #include <linux/wait.h>
23 #include <linux/module.h>
24 #include <asm/uaccess.h>
25 #include <linux/seq_file.h>
26 #include <linux/debugfs.h>
27 #include <linux/kthread.h>
28 #include <linux/freezer.h>
29 #include <linux/workqueue.h>
30 #include <linux/jiffies.h>
31 #include <linux/rcupdate.h>
32 #include <linux/rculist_bl.h>
33 #include <linux/bit_spinlock.h>
34 #include <linux/percpu.h>
35 #include <linux/list_sort.h>
36 #include <linux/lockref.h>
37
38 #include "gfs2.h"
39 #include "incore.h"
40 #include "glock.h"
41 #include "glops.h"
42 #include "inode.h"
43 #include "lops.h"
44 #include "meta_io.h"
45 #include "quota.h"
46 #include "super.h"
47 #include "util.h"
48 #include "bmap.h"
49 #define CREATE_TRACE_POINTS
50 #include "trace_gfs2.h"
51
52 struct gfs2_glock_iter {
53 int hash; /* hash bucket index */
54 unsigned nhash; /* Index within current bucket */
55 struct gfs2_sbd *sdp; /* incore superblock */
56 struct gfs2_glock *gl; /* current glock struct */
57 loff_t last_pos; /* last position */
58 };
59
60 typedef void (*glock_examiner) (struct gfs2_glock * gl);
61
62 static void do_xmote(struct gfs2_glock *gl, struct gfs2_holder *gh, unsigned int target);
63
64 static struct dentry *gfs2_root;
65 static struct workqueue_struct *glock_workqueue;
66 struct workqueue_struct *gfs2_delete_workqueue;
67 static LIST_HEAD(lru_list);
68 static atomic_t lru_count = ATOMIC_INIT(0);
69 static DEFINE_SPINLOCK(lru_lock);
70
71 #define GFS2_GL_HASH_SHIFT 15
72 #define GFS2_GL_HASH_SIZE (1 << GFS2_GL_HASH_SHIFT)
73 #define GFS2_GL_HASH_MASK (GFS2_GL_HASH_SIZE - 1)
74
75 static struct hlist_bl_head gl_hash_table[GFS2_GL_HASH_SIZE];
76 static struct dentry *gfs2_root;
77
78 /**
79 * gl_hash() - Turn glock number into hash bucket number
80 * @lock: The glock number
81 *
82 * Returns: The number of the corresponding hash bucket
83 */
84
85 static unsigned int gl_hash(const struct gfs2_sbd *sdp,
86 const struct lm_lockname *name)
87 {
88 unsigned int h;
89
90 h = jhash(&name->ln_number, sizeof(u64), 0);
91 h = jhash(&name->ln_type, sizeof(unsigned int), h);
92 h = jhash(&sdp, sizeof(struct gfs2_sbd *), h);
93 h &= GFS2_GL_HASH_MASK;
94
95 return h;
96 }
97
98 static inline void spin_lock_bucket(unsigned int hash)
99 {
100 hlist_bl_lock(&gl_hash_table[hash]);
101 }
102
103 static inline void spin_unlock_bucket(unsigned int hash)
104 {
105 hlist_bl_unlock(&gl_hash_table[hash]);
106 }
107
108 static void gfs2_glock_dealloc(struct rcu_head *rcu)
109 {
110 struct gfs2_glock *gl = container_of(rcu, struct gfs2_glock, gl_rcu);
111
112 if (gl->gl_ops->go_flags & GLOF_ASPACE) {
113 kmem_cache_free(gfs2_glock_aspace_cachep, gl);
114 } else {
115 kfree(gl->gl_lksb.sb_lvbptr);
116 kmem_cache_free(gfs2_glock_cachep, gl);
117 }
118 }
119
120 void gfs2_glock_free(struct gfs2_glock *gl)
121 {
122 struct gfs2_sbd *sdp = gl->gl_sbd;
123
124 call_rcu(&gl->gl_rcu, gfs2_glock_dealloc);
125 if (atomic_dec_and_test(&sdp->sd_glock_disposal))
126 wake_up(&sdp->sd_glock_wait);
127 }
128
129 /**
130 * gfs2_glock_hold() - increment reference count on glock
131 * @gl: The glock to hold
132 *
133 */
134
135 static void gfs2_glock_hold(struct gfs2_glock *gl)
136 {
137 GLOCK_BUG_ON(gl, __lockref_is_dead(&gl->gl_lockref));
138 lockref_get(&gl->gl_lockref);
139 }
140
141 /**
142 * demote_ok - Check to see if it's ok to unlock a glock
143 * @gl: the glock
144 *
145 * Returns: 1 if it's ok
146 */
147
148 static int demote_ok(const struct gfs2_glock *gl)
149 {
150 const struct gfs2_glock_operations *glops = gl->gl_ops;
151
152 if (gl->gl_state == LM_ST_UNLOCKED)
153 return 0;
154 if (!list_empty(&gl->gl_holders))
155 return 0;
156 if (glops->go_demote_ok)
157 return glops->go_demote_ok(gl);
158 return 1;
159 }
160
161
162 void gfs2_glock_add_to_lru(struct gfs2_glock *gl)
163 {
164 spin_lock(&lru_lock);
165
166 if (!list_empty(&gl->gl_lru))
167 list_del_init(&gl->gl_lru);
168 else
169 atomic_inc(&lru_count);
170
171 list_add_tail(&gl->gl_lru, &lru_list);
172 set_bit(GLF_LRU, &gl->gl_flags);
173 spin_unlock(&lru_lock);
174 }
175
176 static void gfs2_glock_remove_from_lru(struct gfs2_glock *gl)
177 {
178 spin_lock(&lru_lock);
179 if (!list_empty(&gl->gl_lru)) {
180 list_del_init(&gl->gl_lru);
181 atomic_dec(&lru_count);
182 clear_bit(GLF_LRU, &gl->gl_flags);
183 }
184 spin_unlock(&lru_lock);
185 }
186
187 /**
188 * gfs2_glock_put() - Decrement reference count on glock
189 * @gl: The glock to put
190 *
191 */
192
193 void gfs2_glock_put(struct gfs2_glock *gl)
194 {
195 struct gfs2_sbd *sdp = gl->gl_sbd;
196 struct address_space *mapping = gfs2_glock2aspace(gl);
197
198 if (lockref_put_or_lock(&gl->gl_lockref))
199 return;
200
201 lockref_mark_dead(&gl->gl_lockref);
202
203 gfs2_glock_remove_from_lru(gl);
204 spin_unlock(&gl->gl_lockref.lock);
205 spin_lock_bucket(gl->gl_hash);
206 hlist_bl_del_rcu(&gl->gl_list);
207 spin_unlock_bucket(gl->gl_hash);
208 GLOCK_BUG_ON(gl, !list_empty(&gl->gl_holders));
209 GLOCK_BUG_ON(gl, mapping && mapping->nrpages);
210 trace_gfs2_glock_put(gl);
211 sdp->sd_lockstruct.ls_ops->lm_put_lock(gl);
212 }
213
214 /**
215 * search_bucket() - Find struct gfs2_glock by lock number
216 * @bucket: the bucket to search
217 * @name: The lock name
218 *
219 * Returns: NULL, or the struct gfs2_glock with the requested number
220 */
221
222 static struct gfs2_glock *search_bucket(unsigned int hash,
223 const struct gfs2_sbd *sdp,
224 const struct lm_lockname *name)
225 {
226 struct gfs2_glock *gl;
227 struct hlist_bl_node *h;
228
229 hlist_bl_for_each_entry_rcu(gl, h, &gl_hash_table[hash], gl_list) {
230 if (!lm_name_equal(&gl->gl_name, name))
231 continue;
232 if (gl->gl_sbd != sdp)
233 continue;
234 if (lockref_get_not_dead(&gl->gl_lockref))
235 return gl;
236 }
237
238 return NULL;
239 }
240
241 /**
242 * may_grant - check if its ok to grant a new lock
243 * @gl: The glock
244 * @gh: The lock request which we wish to grant
245 *
246 * Returns: true if its ok to grant the lock
247 */
248
249 static inline int may_grant(const struct gfs2_glock *gl, const struct gfs2_holder *gh)
250 {
251 const struct gfs2_holder *gh_head = list_entry(gl->gl_holders.next, const struct gfs2_holder, gh_list);
252 if ((gh->gh_state == LM_ST_EXCLUSIVE ||
253 gh_head->gh_state == LM_ST_EXCLUSIVE) && gh != gh_head)
254 return 0;
255 if (gl->gl_state == gh->gh_state)
256 return 1;
257 if (gh->gh_flags & GL_EXACT)
258 return 0;
259 if (gl->gl_state == LM_ST_EXCLUSIVE) {
260 if (gh->gh_state == LM_ST_SHARED && gh_head->gh_state == LM_ST_SHARED)
261 return 1;
262 if (gh->gh_state == LM_ST_DEFERRED && gh_head->gh_state == LM_ST_DEFERRED)
263 return 1;
264 }
265 if (gl->gl_state != LM_ST_UNLOCKED && (gh->gh_flags & LM_FLAG_ANY))
266 return 1;
267 return 0;
268 }
269
270 static void gfs2_holder_wake(struct gfs2_holder *gh)
271 {
272 clear_bit(HIF_WAIT, &gh->gh_iflags);
273 smp_mb__after_atomic();
274 wake_up_bit(&gh->gh_iflags, HIF_WAIT);
275 }
276
277 /**
278 * do_error - Something unexpected has happened during a lock request
279 *
280 */
281
282 static inline void do_error(struct gfs2_glock *gl, const int ret)
283 {
284 struct gfs2_holder *gh, *tmp;
285
286 list_for_each_entry_safe(gh, tmp, &gl->gl_holders, gh_list) {
287 if (test_bit(HIF_HOLDER, &gh->gh_iflags))
288 continue;
289 if (ret & LM_OUT_ERROR)
290 gh->gh_error = -EIO;
291 else if (gh->gh_flags & (LM_FLAG_TRY | LM_FLAG_TRY_1CB))
292 gh->gh_error = GLR_TRYFAILED;
293 else
294 continue;
295 list_del_init(&gh->gh_list);
296 trace_gfs2_glock_queue(gh, 0);
297 gfs2_holder_wake(gh);
298 }
299 }
300
301 /**
302 * do_promote - promote as many requests as possible on the current queue
303 * @gl: The glock
304 *
305 * Returns: 1 if there is a blocked holder at the head of the list, or 2
306 * if a type specific operation is underway.
307 */
308
309 static int do_promote(struct gfs2_glock *gl)
310 __releases(&gl->gl_spin)
311 __acquires(&gl->gl_spin)
312 {
313 const struct gfs2_glock_operations *glops = gl->gl_ops;
314 struct gfs2_holder *gh, *tmp;
315 int ret;
316
317 restart:
318 list_for_each_entry_safe(gh, tmp, &gl->gl_holders, gh_list) {
319 if (test_bit(HIF_HOLDER, &gh->gh_iflags))
320 continue;
321 if (may_grant(gl, gh)) {
322 if (gh->gh_list.prev == &gl->gl_holders &&
323 glops->go_lock) {
324 spin_unlock(&gl->gl_spin);
325 /* FIXME: eliminate this eventually */
326 ret = glops->go_lock(gh);
327 spin_lock(&gl->gl_spin);
328 if (ret) {
329 if (ret == 1)
330 return 2;
331 gh->gh_error = ret;
332 list_del_init(&gh->gh_list);
333 trace_gfs2_glock_queue(gh, 0);
334 gfs2_holder_wake(gh);
335 goto restart;
336 }
337 set_bit(HIF_HOLDER, &gh->gh_iflags);
338 trace_gfs2_promote(gh, 1);
339 gfs2_holder_wake(gh);
340 goto restart;
341 }
342 set_bit(HIF_HOLDER, &gh->gh_iflags);
343 trace_gfs2_promote(gh, 0);
344 gfs2_holder_wake(gh);
345 continue;
346 }
347 if (gh->gh_list.prev == &gl->gl_holders)
348 return 1;
349 do_error(gl, 0);
350 break;
351 }
352 return 0;
353 }
354
355 /**
356 * find_first_waiter - find the first gh that's waiting for the glock
357 * @gl: the glock
358 */
359
360 static inline struct gfs2_holder *find_first_waiter(const struct gfs2_glock *gl)
361 {
362 struct gfs2_holder *gh;
363
364 list_for_each_entry(gh, &gl->gl_holders, gh_list) {
365 if (!test_bit(HIF_HOLDER, &gh->gh_iflags))
366 return gh;
367 }
368 return NULL;
369 }
370
371 /**
372 * state_change - record that the glock is now in a different state
373 * @gl: the glock
374 * @new_state the new state
375 *
376 */
377
378 static void state_change(struct gfs2_glock *gl, unsigned int new_state)
379 {
380 int held1, held2;
381
382 held1 = (gl->gl_state != LM_ST_UNLOCKED);
383 held2 = (new_state != LM_ST_UNLOCKED);
384
385 if (held1 != held2) {
386 GLOCK_BUG_ON(gl, __lockref_is_dead(&gl->gl_lockref));
387 if (held2)
388 gl->gl_lockref.count++;
389 else
390 gl->gl_lockref.count--;
391 }
392 if (held1 && held2 && list_empty(&gl->gl_holders))
393 clear_bit(GLF_QUEUED, &gl->gl_flags);
394
395 if (new_state != gl->gl_target)
396 /* shorten our minimum hold time */
397 gl->gl_hold_time = max(gl->gl_hold_time - GL_GLOCK_HOLD_DECR,
398 GL_GLOCK_MIN_HOLD);
399 gl->gl_state = new_state;
400 gl->gl_tchange = jiffies;
401 }
402
403 static void gfs2_demote_wake(struct gfs2_glock *gl)
404 {
405 gl->gl_demote_state = LM_ST_EXCLUSIVE;
406 clear_bit(GLF_DEMOTE, &gl->gl_flags);
407 smp_mb__after_atomic();
408 wake_up_bit(&gl->gl_flags, GLF_DEMOTE);
409 }
410
411 /**
412 * finish_xmote - The DLM has replied to one of our lock requests
413 * @gl: The glock
414 * @ret: The status from the DLM
415 *
416 */
417
418 static void finish_xmote(struct gfs2_glock *gl, unsigned int ret)
419 {
420 const struct gfs2_glock_operations *glops = gl->gl_ops;
421 struct gfs2_holder *gh;
422 unsigned state = ret & LM_OUT_ST_MASK;
423 int rv;
424
425 spin_lock(&gl->gl_spin);
426 trace_gfs2_glock_state_change(gl, state);
427 state_change(gl, state);
428 gh = find_first_waiter(gl);
429
430 /* Demote to UN request arrived during demote to SH or DF */
431 if (test_bit(GLF_DEMOTE_IN_PROGRESS, &gl->gl_flags) &&
432 state != LM_ST_UNLOCKED && gl->gl_demote_state == LM_ST_UNLOCKED)
433 gl->gl_target = LM_ST_UNLOCKED;
434
435 /* Check for state != intended state */
436 if (unlikely(state != gl->gl_target)) {
437 if (gh && !test_bit(GLF_DEMOTE_IN_PROGRESS, &gl->gl_flags)) {
438 /* move to back of queue and try next entry */
439 if (ret & LM_OUT_CANCELED) {
440 if ((gh->gh_flags & LM_FLAG_PRIORITY) == 0)
441 list_move_tail(&gh->gh_list, &gl->gl_holders);
442 gh = find_first_waiter(gl);
443 gl->gl_target = gh->gh_state;
444 goto retry;
445 }
446 /* Some error or failed "try lock" - report it */
447 if ((ret & LM_OUT_ERROR) ||
448 (gh->gh_flags & (LM_FLAG_TRY | LM_FLAG_TRY_1CB))) {
449 gl->gl_target = gl->gl_state;
450 do_error(gl, ret);
451 goto out;
452 }
453 }
454 switch(state) {
455 /* Unlocked due to conversion deadlock, try again */
456 case LM_ST_UNLOCKED:
457 retry:
458 do_xmote(gl, gh, gl->gl_target);
459 break;
460 /* Conversion fails, unlock and try again */
461 case LM_ST_SHARED:
462 case LM_ST_DEFERRED:
463 do_xmote(gl, gh, LM_ST_UNLOCKED);
464 break;
465 default: /* Everything else */
466 pr_err("wanted %u got %u\n", gl->gl_target, state);
467 GLOCK_BUG_ON(gl, 1);
468 }
469 spin_unlock(&gl->gl_spin);
470 return;
471 }
472
473 /* Fast path - we got what we asked for */
474 if (test_and_clear_bit(GLF_DEMOTE_IN_PROGRESS, &gl->gl_flags))
475 gfs2_demote_wake(gl);
476 if (state != LM_ST_UNLOCKED) {
477 if (glops->go_xmote_bh) {
478 spin_unlock(&gl->gl_spin);
479 rv = glops->go_xmote_bh(gl, gh);
480 spin_lock(&gl->gl_spin);
481 if (rv) {
482 do_error(gl, rv);
483 goto out;
484 }
485 }
486 rv = do_promote(gl);
487 if (rv == 2)
488 goto out_locked;
489 }
490 out:
491 clear_bit(GLF_LOCK, &gl->gl_flags);
492 out_locked:
493 spin_unlock(&gl->gl_spin);
494 }
495
496 /**
497 * do_xmote - Calls the DLM to change the state of a lock
498 * @gl: The lock state
499 * @gh: The holder (only for promotes)
500 * @target: The target lock state
501 *
502 */
503
504 static void do_xmote(struct gfs2_glock *gl, struct gfs2_holder *gh, unsigned int target)
505 __releases(&gl->gl_spin)
506 __acquires(&gl->gl_spin)
507 {
508 const struct gfs2_glock_operations *glops = gl->gl_ops;
509 struct gfs2_sbd *sdp = gl->gl_sbd;
510 unsigned int lck_flags = gh ? gh->gh_flags : 0;
511 int ret;
512
513 lck_flags &= (LM_FLAG_TRY | LM_FLAG_TRY_1CB | LM_FLAG_NOEXP |
514 LM_FLAG_PRIORITY);
515 GLOCK_BUG_ON(gl, gl->gl_state == target);
516 GLOCK_BUG_ON(gl, gl->gl_state == gl->gl_target);
517 if ((target == LM_ST_UNLOCKED || target == LM_ST_DEFERRED) &&
518 glops->go_inval) {
519 set_bit(GLF_INVALIDATE_IN_PROGRESS, &gl->gl_flags);
520 do_error(gl, 0); /* Fail queued try locks */
521 }
522 gl->gl_req = target;
523 set_bit(GLF_BLOCKING, &gl->gl_flags);
524 if ((gl->gl_req == LM_ST_UNLOCKED) ||
525 (gl->gl_state == LM_ST_EXCLUSIVE) ||
526 (lck_flags & (LM_FLAG_TRY|LM_FLAG_TRY_1CB)))
527 clear_bit(GLF_BLOCKING, &gl->gl_flags);
528 spin_unlock(&gl->gl_spin);
529 if (glops->go_sync)
530 glops->go_sync(gl);
531 if (test_bit(GLF_INVALIDATE_IN_PROGRESS, &gl->gl_flags))
532 glops->go_inval(gl, target == LM_ST_DEFERRED ? 0 : DIO_METADATA);
533 clear_bit(GLF_INVALIDATE_IN_PROGRESS, &gl->gl_flags);
534
535 gfs2_glock_hold(gl);
536 if (sdp->sd_lockstruct.ls_ops->lm_lock) {
537 /* lock_dlm */
538 ret = sdp->sd_lockstruct.ls_ops->lm_lock(gl, target, lck_flags);
539 if (ret) {
540 pr_err("lm_lock ret %d\n", ret);
541 GLOCK_BUG_ON(gl, 1);
542 }
543 } else { /* lock_nolock */
544 finish_xmote(gl, target);
545 if (queue_delayed_work(glock_workqueue, &gl->gl_work, 0) == 0)
546 gfs2_glock_put(gl);
547 }
548
549 spin_lock(&gl->gl_spin);
550 }
551
552 /**
553 * find_first_holder - find the first "holder" gh
554 * @gl: the glock
555 */
556
557 static inline struct gfs2_holder *find_first_holder(const struct gfs2_glock *gl)
558 {
559 struct gfs2_holder *gh;
560
561 if (!list_empty(&gl->gl_holders)) {
562 gh = list_entry(gl->gl_holders.next, struct gfs2_holder, gh_list);
563 if (test_bit(HIF_HOLDER, &gh->gh_iflags))
564 return gh;
565 }
566 return NULL;
567 }
568
569 /**
570 * run_queue - do all outstanding tasks related to a glock
571 * @gl: The glock in question
572 * @nonblock: True if we must not block in run_queue
573 *
574 */
575
576 static void run_queue(struct gfs2_glock *gl, const int nonblock)
577 __releases(&gl->gl_spin)
578 __acquires(&gl->gl_spin)
579 {
580 struct gfs2_holder *gh = NULL;
581 int ret;
582
583 if (test_and_set_bit(GLF_LOCK, &gl->gl_flags))
584 return;
585
586 GLOCK_BUG_ON(gl, test_bit(GLF_DEMOTE_IN_PROGRESS, &gl->gl_flags));
587
588 if (test_bit(GLF_DEMOTE, &gl->gl_flags) &&
589 gl->gl_demote_state != gl->gl_state) {
590 if (find_first_holder(gl))
591 goto out_unlock;
592 if (nonblock)
593 goto out_sched;
594 set_bit(GLF_DEMOTE_IN_PROGRESS, &gl->gl_flags);
595 GLOCK_BUG_ON(gl, gl->gl_demote_state == LM_ST_EXCLUSIVE);
596 gl->gl_target = gl->gl_demote_state;
597 } else {
598 if (test_bit(GLF_DEMOTE, &gl->gl_flags))
599 gfs2_demote_wake(gl);
600 ret = do_promote(gl);
601 if (ret == 0)
602 goto out_unlock;
603 if (ret == 2)
604 goto out;
605 gh = find_first_waiter(gl);
606 gl->gl_target = gh->gh_state;
607 if (!(gh->gh_flags & (LM_FLAG_TRY | LM_FLAG_TRY_1CB)))
608 do_error(gl, 0); /* Fail queued try locks */
609 }
610 do_xmote(gl, gh, gl->gl_target);
611 out:
612 return;
613
614 out_sched:
615 clear_bit(GLF_LOCK, &gl->gl_flags);
616 smp_mb__after_atomic();
617 gl->gl_lockref.count++;
618 if (queue_delayed_work(glock_workqueue, &gl->gl_work, 0) == 0)
619 gl->gl_lockref.count--;
620 return;
621
622 out_unlock:
623 clear_bit(GLF_LOCK, &gl->gl_flags);
624 smp_mb__after_atomic();
625 return;
626 }
627
628 static void delete_work_func(struct work_struct *work)
629 {
630 struct gfs2_glock *gl = container_of(work, struct gfs2_glock, gl_delete);
631 struct gfs2_sbd *sdp = gl->gl_sbd;
632 struct gfs2_inode *ip;
633 struct inode *inode;
634 u64 no_addr = gl->gl_name.ln_number;
635
636 ip = gl->gl_object;
637 /* Note: Unsafe to dereference ip as we don't hold right refs/locks */
638
639 if (ip)
640 inode = gfs2_ilookup(sdp->sd_vfs, no_addr, 1);
641 else
642 inode = gfs2_lookup_by_inum(sdp, no_addr, NULL, GFS2_BLKST_UNLINKED);
643 if (inode && !IS_ERR(inode)) {
644 d_prune_aliases(inode);
645 iput(inode);
646 }
647 gfs2_glock_put(gl);
648 }
649
650 static void glock_work_func(struct work_struct *work)
651 {
652 unsigned long delay = 0;
653 struct gfs2_glock *gl = container_of(work, struct gfs2_glock, gl_work.work);
654 int drop_ref = 0;
655
656 if (test_and_clear_bit(GLF_REPLY_PENDING, &gl->gl_flags)) {
657 finish_xmote(gl, gl->gl_reply);
658 drop_ref = 1;
659 }
660 spin_lock(&gl->gl_spin);
661 if (test_bit(GLF_PENDING_DEMOTE, &gl->gl_flags) &&
662 gl->gl_state != LM_ST_UNLOCKED &&
663 gl->gl_demote_state != LM_ST_EXCLUSIVE) {
664 unsigned long holdtime, now = jiffies;
665
666 holdtime = gl->gl_tchange + gl->gl_hold_time;
667 if (time_before(now, holdtime))
668 delay = holdtime - now;
669
670 if (!delay) {
671 clear_bit(GLF_PENDING_DEMOTE, &gl->gl_flags);
672 set_bit(GLF_DEMOTE, &gl->gl_flags);
673 }
674 }
675 run_queue(gl, 0);
676 spin_unlock(&gl->gl_spin);
677 if (!delay)
678 gfs2_glock_put(gl);
679 else {
680 if (gl->gl_name.ln_type != LM_TYPE_INODE)
681 delay = 0;
682 if (queue_delayed_work(glock_workqueue, &gl->gl_work, delay) == 0)
683 gfs2_glock_put(gl);
684 }
685 if (drop_ref)
686 gfs2_glock_put(gl);
687 }
688
689 /**
690 * gfs2_glock_get() - Get a glock, or create one if one doesn't exist
691 * @sdp: The GFS2 superblock
692 * @number: the lock number
693 * @glops: The glock_operations to use
694 * @create: If 0, don't create the glock if it doesn't exist
695 * @glp: the glock is returned here
696 *
697 * This does not lock a glock, just finds/creates structures for one.
698 *
699 * Returns: errno
700 */
701
702 int gfs2_glock_get(struct gfs2_sbd *sdp, u64 number,
703 const struct gfs2_glock_operations *glops, int create,
704 struct gfs2_glock **glp)
705 {
706 struct super_block *s = sdp->sd_vfs;
707 struct lm_lockname name = { .ln_number = number, .ln_type = glops->go_type };
708 struct gfs2_glock *gl, *tmp;
709 unsigned int hash = gl_hash(sdp, &name);
710 struct address_space *mapping;
711 struct kmem_cache *cachep;
712
713 rcu_read_lock();
714 gl = search_bucket(hash, sdp, &name);
715 rcu_read_unlock();
716
717 *glp = gl;
718 if (gl)
719 return 0;
720 if (!create)
721 return -ENOENT;
722
723 if (glops->go_flags & GLOF_ASPACE)
724 cachep = gfs2_glock_aspace_cachep;
725 else
726 cachep = gfs2_glock_cachep;
727 gl = kmem_cache_alloc(cachep, GFP_NOFS);
728 if (!gl)
729 return -ENOMEM;
730
731 memset(&gl->gl_lksb, 0, sizeof(struct dlm_lksb));
732
733 if (glops->go_flags & GLOF_LVB) {
734 gl->gl_lksb.sb_lvbptr = kzalloc(GFS2_MIN_LVB_SIZE, GFP_NOFS);
735 if (!gl->gl_lksb.sb_lvbptr) {
736 kmem_cache_free(cachep, gl);
737 return -ENOMEM;
738 }
739 }
740
741 atomic_inc(&sdp->sd_glock_disposal);
742 gl->gl_sbd = sdp;
743 gl->gl_flags = 0;
744 gl->gl_name = name;
745 gl->gl_lockref.count = 1;
746 gl->gl_state = LM_ST_UNLOCKED;
747 gl->gl_target = LM_ST_UNLOCKED;
748 gl->gl_demote_state = LM_ST_EXCLUSIVE;
749 gl->gl_hash = hash;
750 gl->gl_ops = glops;
751 gl->gl_dstamp = ktime_set(0, 0);
752 preempt_disable();
753 /* We use the global stats to estimate the initial per-glock stats */
754 gl->gl_stats = this_cpu_ptr(sdp->sd_lkstats)->lkstats[glops->go_type];
755 preempt_enable();
756 gl->gl_stats.stats[GFS2_LKS_DCOUNT] = 0;
757 gl->gl_stats.stats[GFS2_LKS_QCOUNT] = 0;
758 gl->gl_tchange = jiffies;
759 gl->gl_object = NULL;
760 gl->gl_hold_time = GL_GLOCK_DFT_HOLD;
761 INIT_DELAYED_WORK(&gl->gl_work, glock_work_func);
762 INIT_WORK(&gl->gl_delete, delete_work_func);
763
764 mapping = gfs2_glock2aspace(gl);
765 if (mapping) {
766 mapping->a_ops = &gfs2_meta_aops;
767 mapping->host = s->s_bdev->bd_inode;
768 mapping->flags = 0;
769 mapping_set_gfp_mask(mapping, GFP_NOFS);
770 mapping->private_data = NULL;
771 mapping->writeback_index = 0;
772 }
773
774 spin_lock_bucket(hash);
775 tmp = search_bucket(hash, sdp, &name);
776 if (tmp) {
777 spin_unlock_bucket(hash);
778 kfree(gl->gl_lksb.sb_lvbptr);
779 kmem_cache_free(cachep, gl);
780 atomic_dec(&sdp->sd_glock_disposal);
781 gl = tmp;
782 } else {
783 hlist_bl_add_head_rcu(&gl->gl_list, &gl_hash_table[hash]);
784 spin_unlock_bucket(hash);
785 }
786
787 *glp = gl;
788
789 return 0;
790 }
791
792 /**
793 * gfs2_holder_init - initialize a struct gfs2_holder in the default way
794 * @gl: the glock
795 * @state: the state we're requesting
796 * @flags: the modifier flags
797 * @gh: the holder structure
798 *
799 */
800
801 void gfs2_holder_init(struct gfs2_glock *gl, unsigned int state, unsigned flags,
802 struct gfs2_holder *gh)
803 {
804 INIT_LIST_HEAD(&gh->gh_list);
805 gh->gh_gl = gl;
806 gh->gh_ip = _RET_IP_;
807 gh->gh_owner_pid = get_pid(task_pid(current));
808 gh->gh_state = state;
809 gh->gh_flags = flags;
810 gh->gh_error = 0;
811 gh->gh_iflags = 0;
812 gfs2_glock_hold(gl);
813 }
814
815 /**
816 * gfs2_holder_reinit - reinitialize a struct gfs2_holder so we can requeue it
817 * @state: the state we're requesting
818 * @flags: the modifier flags
819 * @gh: the holder structure
820 *
821 * Don't mess with the glock.
822 *
823 */
824
825 void gfs2_holder_reinit(unsigned int state, unsigned flags, struct gfs2_holder *gh)
826 {
827 gh->gh_state = state;
828 gh->gh_flags = flags;
829 gh->gh_iflags = 0;
830 gh->gh_ip = _RET_IP_;
831 put_pid(gh->gh_owner_pid);
832 gh->gh_owner_pid = get_pid(task_pid(current));
833 }
834
835 /**
836 * gfs2_holder_uninit - uninitialize a holder structure (drop glock reference)
837 * @gh: the holder structure
838 *
839 */
840
841 void gfs2_holder_uninit(struct gfs2_holder *gh)
842 {
843 put_pid(gh->gh_owner_pid);
844 gfs2_glock_put(gh->gh_gl);
845 gh->gh_gl = NULL;
846 gh->gh_ip = 0;
847 }
848
849 /**
850 * gfs2_glock_wait - wait on a glock acquisition
851 * @gh: the glock holder
852 *
853 * Returns: 0 on success
854 */
855
856 int gfs2_glock_wait(struct gfs2_holder *gh)
857 {
858 unsigned long time1 = jiffies;
859
860 might_sleep();
861 wait_on_bit(&gh->gh_iflags, HIF_WAIT, TASK_UNINTERRUPTIBLE);
862 if (time_after(jiffies, time1 + HZ)) /* have we waited > a second? */
863 /* Lengthen the minimum hold time. */
864 gh->gh_gl->gl_hold_time = min(gh->gh_gl->gl_hold_time +
865 GL_GLOCK_HOLD_INCR,
866 GL_GLOCK_MAX_HOLD);
867 return gh->gh_error;
868 }
869
870 /**
871 * handle_callback - process a demote request
872 * @gl: the glock
873 * @state: the state the caller wants us to change to
874 *
875 * There are only two requests that we are going to see in actual
876 * practise: LM_ST_SHARED and LM_ST_UNLOCKED
877 */
878
879 static void handle_callback(struct gfs2_glock *gl, unsigned int state,
880 unsigned long delay, bool remote)
881 {
882 int bit = delay ? GLF_PENDING_DEMOTE : GLF_DEMOTE;
883
884 set_bit(bit, &gl->gl_flags);
885 if (gl->gl_demote_state == LM_ST_EXCLUSIVE) {
886 gl->gl_demote_state = state;
887 gl->gl_demote_time = jiffies;
888 } else if (gl->gl_demote_state != LM_ST_UNLOCKED &&
889 gl->gl_demote_state != state) {
890 gl->gl_demote_state = LM_ST_UNLOCKED;
891 }
892 if (gl->gl_ops->go_callback)
893 gl->gl_ops->go_callback(gl, remote);
894 trace_gfs2_demote_rq(gl, remote);
895 }
896
897 void gfs2_print_dbg(struct seq_file *seq, const char *fmt, ...)
898 {
899 struct va_format vaf;
900 va_list args;
901
902 va_start(args, fmt);
903
904 if (seq) {
905 seq_vprintf(seq, fmt, args);
906 } else {
907 vaf.fmt = fmt;
908 vaf.va = &args;
909
910 pr_err("%pV", &vaf);
911 }
912
913 va_end(args);
914 }
915
916 /**
917 * add_to_queue - Add a holder to the wait queue (but look for recursion)
918 * @gh: the holder structure to add
919 *
920 * Eventually we should move the recursive locking trap to a
921 * debugging option or something like that. This is the fast
922 * path and needs to have the minimum number of distractions.
923 *
924 */
925
926 static inline void add_to_queue(struct gfs2_holder *gh)
927 __releases(&gl->gl_spin)
928 __acquires(&gl->gl_spin)
929 {
930 struct gfs2_glock *gl = gh->gh_gl;
931 struct gfs2_sbd *sdp = gl->gl_sbd;
932 struct list_head *insert_pt = NULL;
933 struct gfs2_holder *gh2;
934 int try_futile = 0;
935
936 BUG_ON(gh->gh_owner_pid == NULL);
937 if (test_and_set_bit(HIF_WAIT, &gh->gh_iflags))
938 BUG();
939
940 if (gh->gh_flags & (LM_FLAG_TRY | LM_FLAG_TRY_1CB)) {
941 if (test_bit(GLF_LOCK, &gl->gl_flags))
942 try_futile = !may_grant(gl, gh);
943 if (test_bit(GLF_INVALIDATE_IN_PROGRESS, &gl->gl_flags))
944 goto fail;
945 }
946
947 list_for_each_entry(gh2, &gl->gl_holders, gh_list) {
948 if (unlikely(gh2->gh_owner_pid == gh->gh_owner_pid &&
949 (gh->gh_gl->gl_ops->go_type != LM_TYPE_FLOCK)))
950 goto trap_recursive;
951 if (try_futile &&
952 !(gh2->gh_flags & (LM_FLAG_TRY | LM_FLAG_TRY_1CB))) {
953 fail:
954 gh->gh_error = GLR_TRYFAILED;
955 gfs2_holder_wake(gh);
956 return;
957 }
958 if (test_bit(HIF_HOLDER, &gh2->gh_iflags))
959 continue;
960 if (unlikely((gh->gh_flags & LM_FLAG_PRIORITY) && !insert_pt))
961 insert_pt = &gh2->gh_list;
962 }
963 set_bit(GLF_QUEUED, &gl->gl_flags);
964 trace_gfs2_glock_queue(gh, 1);
965 gfs2_glstats_inc(gl, GFS2_LKS_QCOUNT);
966 gfs2_sbstats_inc(gl, GFS2_LKS_QCOUNT);
967 if (likely(insert_pt == NULL)) {
968 list_add_tail(&gh->gh_list, &gl->gl_holders);
969 if (unlikely(gh->gh_flags & LM_FLAG_PRIORITY))
970 goto do_cancel;
971 return;
972 }
973 list_add_tail(&gh->gh_list, insert_pt);
974 do_cancel:
975 gh = list_entry(gl->gl_holders.next, struct gfs2_holder, gh_list);
976 if (!(gh->gh_flags & LM_FLAG_PRIORITY)) {
977 spin_unlock(&gl->gl_spin);
978 if (sdp->sd_lockstruct.ls_ops->lm_cancel)
979 sdp->sd_lockstruct.ls_ops->lm_cancel(gl);
980 spin_lock(&gl->gl_spin);
981 }
982 return;
983
984 trap_recursive:
985 pr_err("original: %pSR\n", (void *)gh2->gh_ip);
986 pr_err("pid: %d\n", pid_nr(gh2->gh_owner_pid));
987 pr_err("lock type: %d req lock state : %d\n",
988 gh2->gh_gl->gl_name.ln_type, gh2->gh_state);
989 pr_err("new: %pSR\n", (void *)gh->gh_ip);
990 pr_err("pid: %d\n", pid_nr(gh->gh_owner_pid));
991 pr_err("lock type: %d req lock state : %d\n",
992 gh->gh_gl->gl_name.ln_type, gh->gh_state);
993 gfs2_dump_glock(NULL, gl);
994 BUG();
995 }
996
997 /**
998 * gfs2_glock_nq - enqueue a struct gfs2_holder onto a glock (acquire a glock)
999 * @gh: the holder structure
1000 *
1001 * if (gh->gh_flags & GL_ASYNC), this never returns an error
1002 *
1003 * Returns: 0, GLR_TRYFAILED, or errno on failure
1004 */
1005
1006 int gfs2_glock_nq(struct gfs2_holder *gh)
1007 {
1008 struct gfs2_glock *gl = gh->gh_gl;
1009 struct gfs2_sbd *sdp = gl->gl_sbd;
1010 int error = 0;
1011
1012 if (unlikely(test_bit(SDF_SHUTDOWN, &sdp->sd_flags)))
1013 return -EIO;
1014
1015 if (test_bit(GLF_LRU, &gl->gl_flags))
1016 gfs2_glock_remove_from_lru(gl);
1017
1018 spin_lock(&gl->gl_spin);
1019 add_to_queue(gh);
1020 if (unlikely((LM_FLAG_NOEXP & gh->gh_flags) &&
1021 test_and_clear_bit(GLF_FROZEN, &gl->gl_flags))) {
1022 set_bit(GLF_REPLY_PENDING, &gl->gl_flags);
1023 gl->gl_lockref.count++;
1024 if (queue_delayed_work(glock_workqueue, &gl->gl_work, 0) == 0)
1025 gl->gl_lockref.count--;
1026 }
1027 run_queue(gl, 1);
1028 spin_unlock(&gl->gl_spin);
1029
1030 if (!(gh->gh_flags & GL_ASYNC))
1031 error = gfs2_glock_wait(gh);
1032
1033 return error;
1034 }
1035
1036 /**
1037 * gfs2_glock_poll - poll to see if an async request has been completed
1038 * @gh: the holder
1039 *
1040 * Returns: 1 if the request is ready to be gfs2_glock_wait()ed on
1041 */
1042
1043 int gfs2_glock_poll(struct gfs2_holder *gh)
1044 {
1045 return test_bit(HIF_WAIT, &gh->gh_iflags) ? 0 : 1;
1046 }
1047
1048 /**
1049 * gfs2_glock_dq - dequeue a struct gfs2_holder from a glock (release a glock)
1050 * @gh: the glock holder
1051 *
1052 */
1053
1054 void gfs2_glock_dq(struct gfs2_holder *gh)
1055 {
1056 struct gfs2_glock *gl = gh->gh_gl;
1057 const struct gfs2_glock_operations *glops = gl->gl_ops;
1058 unsigned delay = 0;
1059 int fast_path = 0;
1060
1061 spin_lock(&gl->gl_spin);
1062 if (gh->gh_flags & GL_NOCACHE)
1063 handle_callback(gl, LM_ST_UNLOCKED, 0, false);
1064
1065 list_del_init(&gh->gh_list);
1066 if (find_first_holder(gl) == NULL) {
1067 if (glops->go_unlock) {
1068 GLOCK_BUG_ON(gl, test_and_set_bit(GLF_LOCK, &gl->gl_flags));
1069 spin_unlock(&gl->gl_spin);
1070 glops->go_unlock(gh);
1071 spin_lock(&gl->gl_spin);
1072 clear_bit(GLF_LOCK, &gl->gl_flags);
1073 }
1074 if (list_empty(&gl->gl_holders) &&
1075 !test_bit(GLF_PENDING_DEMOTE, &gl->gl_flags) &&
1076 !test_bit(GLF_DEMOTE, &gl->gl_flags))
1077 fast_path = 1;
1078 }
1079 if (!test_bit(GLF_LFLUSH, &gl->gl_flags) && demote_ok(gl))
1080 gfs2_glock_add_to_lru(gl);
1081
1082 trace_gfs2_glock_queue(gh, 0);
1083 spin_unlock(&gl->gl_spin);
1084 if (likely(fast_path))
1085 return;
1086
1087 gfs2_glock_hold(gl);
1088 if (test_bit(GLF_PENDING_DEMOTE, &gl->gl_flags) &&
1089 !test_bit(GLF_DEMOTE, &gl->gl_flags) &&
1090 gl->gl_name.ln_type == LM_TYPE_INODE)
1091 delay = gl->gl_hold_time;
1092 if (queue_delayed_work(glock_workqueue, &gl->gl_work, delay) == 0)
1093 gfs2_glock_put(gl);
1094 }
1095
1096 void gfs2_glock_dq_wait(struct gfs2_holder *gh)
1097 {
1098 struct gfs2_glock *gl = gh->gh_gl;
1099 gfs2_glock_dq(gh);
1100 might_sleep();
1101 wait_on_bit(&gl->gl_flags, GLF_DEMOTE, TASK_UNINTERRUPTIBLE);
1102 }
1103
1104 /**
1105 * gfs2_glock_dq_uninit - dequeue a holder from a glock and initialize it
1106 * @gh: the holder structure
1107 *
1108 */
1109
1110 void gfs2_glock_dq_uninit(struct gfs2_holder *gh)
1111 {
1112 gfs2_glock_dq(gh);
1113 gfs2_holder_uninit(gh);
1114 }
1115
1116 /**
1117 * gfs2_glock_nq_num - acquire a glock based on lock number
1118 * @sdp: the filesystem
1119 * @number: the lock number
1120 * @glops: the glock operations for the type of glock
1121 * @state: the state to acquire the glock in
1122 * @flags: modifier flags for the acquisition
1123 * @gh: the struct gfs2_holder
1124 *
1125 * Returns: errno
1126 */
1127
1128 int gfs2_glock_nq_num(struct gfs2_sbd *sdp, u64 number,
1129 const struct gfs2_glock_operations *glops,
1130 unsigned int state, int flags, struct gfs2_holder *gh)
1131 {
1132 struct gfs2_glock *gl;
1133 int error;
1134
1135 error = gfs2_glock_get(sdp, number, glops, CREATE, &gl);
1136 if (!error) {
1137 error = gfs2_glock_nq_init(gl, state, flags, gh);
1138 gfs2_glock_put(gl);
1139 }
1140
1141 return error;
1142 }
1143
1144 /**
1145 * glock_compare - Compare two struct gfs2_glock structures for sorting
1146 * @arg_a: the first structure
1147 * @arg_b: the second structure
1148 *
1149 */
1150
1151 static int glock_compare(const void *arg_a, const void *arg_b)
1152 {
1153 const struct gfs2_holder *gh_a = *(const struct gfs2_holder **)arg_a;
1154 const struct gfs2_holder *gh_b = *(const struct gfs2_holder **)arg_b;
1155 const struct lm_lockname *a = &gh_a->gh_gl->gl_name;
1156 const struct lm_lockname *b = &gh_b->gh_gl->gl_name;
1157
1158 if (a->ln_number > b->ln_number)
1159 return 1;
1160 if (a->ln_number < b->ln_number)
1161 return -1;
1162 BUG_ON(gh_a->gh_gl->gl_ops->go_type == gh_b->gh_gl->gl_ops->go_type);
1163 return 0;
1164 }
1165
1166 /**
1167 * nq_m_sync - synchonously acquire more than one glock in deadlock free order
1168 * @num_gh: the number of structures
1169 * @ghs: an array of struct gfs2_holder structures
1170 *
1171 * Returns: 0 on success (all glocks acquired),
1172 * errno on failure (no glocks acquired)
1173 */
1174
1175 static int nq_m_sync(unsigned int num_gh, struct gfs2_holder *ghs,
1176 struct gfs2_holder **p)
1177 {
1178 unsigned int x;
1179 int error = 0;
1180
1181 for (x = 0; x < num_gh; x++)
1182 p[x] = &ghs[x];
1183
1184 sort(p, num_gh, sizeof(struct gfs2_holder *), glock_compare, NULL);
1185
1186 for (x = 0; x < num_gh; x++) {
1187 p[x]->gh_flags &= ~(LM_FLAG_TRY | GL_ASYNC);
1188
1189 error = gfs2_glock_nq(p[x]);
1190 if (error) {
1191 while (x--)
1192 gfs2_glock_dq(p[x]);
1193 break;
1194 }
1195 }
1196
1197 return error;
1198 }
1199
1200 /**
1201 * gfs2_glock_nq_m - acquire multiple glocks
1202 * @num_gh: the number of structures
1203 * @ghs: an array of struct gfs2_holder structures
1204 *
1205 *
1206 * Returns: 0 on success (all glocks acquired),
1207 * errno on failure (no glocks acquired)
1208 */
1209
1210 int gfs2_glock_nq_m(unsigned int num_gh, struct gfs2_holder *ghs)
1211 {
1212 struct gfs2_holder *tmp[4];
1213 struct gfs2_holder **pph = tmp;
1214 int error = 0;
1215
1216 switch(num_gh) {
1217 case 0:
1218 return 0;
1219 case 1:
1220 ghs->gh_flags &= ~(LM_FLAG_TRY | GL_ASYNC);
1221 return gfs2_glock_nq(ghs);
1222 default:
1223 if (num_gh <= 4)
1224 break;
1225 pph = kmalloc(num_gh * sizeof(struct gfs2_holder *), GFP_NOFS);
1226 if (!pph)
1227 return -ENOMEM;
1228 }
1229
1230 error = nq_m_sync(num_gh, ghs, pph);
1231
1232 if (pph != tmp)
1233 kfree(pph);
1234
1235 return error;
1236 }
1237
1238 /**
1239 * gfs2_glock_dq_m - release multiple glocks
1240 * @num_gh: the number of structures
1241 * @ghs: an array of struct gfs2_holder structures
1242 *
1243 */
1244
1245 void gfs2_glock_dq_m(unsigned int num_gh, struct gfs2_holder *ghs)
1246 {
1247 while (num_gh--)
1248 gfs2_glock_dq(&ghs[num_gh]);
1249 }
1250
1251 void gfs2_glock_cb(struct gfs2_glock *gl, unsigned int state)
1252 {
1253 unsigned long delay = 0;
1254 unsigned long holdtime;
1255 unsigned long now = jiffies;
1256
1257 gfs2_glock_hold(gl);
1258 holdtime = gl->gl_tchange + gl->gl_hold_time;
1259 if (test_bit(GLF_QUEUED, &gl->gl_flags) &&
1260 gl->gl_name.ln_type == LM_TYPE_INODE) {
1261 if (time_before(now, holdtime))
1262 delay = holdtime - now;
1263 if (test_bit(GLF_REPLY_PENDING, &gl->gl_flags))
1264 delay = gl->gl_hold_time;
1265 }
1266
1267 spin_lock(&gl->gl_spin);
1268 handle_callback(gl, state, delay, true);
1269 spin_unlock(&gl->gl_spin);
1270 if (queue_delayed_work(glock_workqueue, &gl->gl_work, delay) == 0)
1271 gfs2_glock_put(gl);
1272 }
1273
1274 /**
1275 * gfs2_should_freeze - Figure out if glock should be frozen
1276 * @gl: The glock in question
1277 *
1278 * Glocks are not frozen if (a) the result of the dlm operation is
1279 * an error, (b) the locking operation was an unlock operation or
1280 * (c) if there is a "noexp" flagged request anywhere in the queue
1281 *
1282 * Returns: 1 if freezing should occur, 0 otherwise
1283 */
1284
1285 static int gfs2_should_freeze(const struct gfs2_glock *gl)
1286 {
1287 const struct gfs2_holder *gh;
1288
1289 if (gl->gl_reply & ~LM_OUT_ST_MASK)
1290 return 0;
1291 if (gl->gl_target == LM_ST_UNLOCKED)
1292 return 0;
1293
1294 list_for_each_entry(gh, &gl->gl_holders, gh_list) {
1295 if (test_bit(HIF_HOLDER, &gh->gh_iflags))
1296 continue;
1297 if (LM_FLAG_NOEXP & gh->gh_flags)
1298 return 0;
1299 }
1300
1301 return 1;
1302 }
1303
1304 /**
1305 * gfs2_glock_complete - Callback used by locking
1306 * @gl: Pointer to the glock
1307 * @ret: The return value from the dlm
1308 *
1309 * The gl_reply field is under the gl_spin lock so that it is ok
1310 * to use a bitfield shared with other glock state fields.
1311 */
1312
1313 void gfs2_glock_complete(struct gfs2_glock *gl, int ret)
1314 {
1315 struct lm_lockstruct *ls = &gl->gl_sbd->sd_lockstruct;
1316
1317 spin_lock(&gl->gl_spin);
1318 gl->gl_reply = ret;
1319
1320 if (unlikely(test_bit(DFL_BLOCK_LOCKS, &ls->ls_recover_flags))) {
1321 if (gfs2_should_freeze(gl)) {
1322 set_bit(GLF_FROZEN, &gl->gl_flags);
1323 spin_unlock(&gl->gl_spin);
1324 return;
1325 }
1326 }
1327
1328 gl->gl_lockref.count++;
1329 set_bit(GLF_REPLY_PENDING, &gl->gl_flags);
1330 spin_unlock(&gl->gl_spin);
1331
1332 if (queue_delayed_work(glock_workqueue, &gl->gl_work, 0) == 0)
1333 gfs2_glock_put(gl);
1334 }
1335
1336 static int glock_cmp(void *priv, struct list_head *a, struct list_head *b)
1337 {
1338 struct gfs2_glock *gla, *glb;
1339
1340 gla = list_entry(a, struct gfs2_glock, gl_lru);
1341 glb = list_entry(b, struct gfs2_glock, gl_lru);
1342
1343 if (gla->gl_name.ln_number > glb->gl_name.ln_number)
1344 return 1;
1345 if (gla->gl_name.ln_number < glb->gl_name.ln_number)
1346 return -1;
1347
1348 return 0;
1349 }
1350
1351 /**
1352 * gfs2_dispose_glock_lru - Demote a list of glocks
1353 * @list: The list to dispose of
1354 *
1355 * Disposing of glocks may involve disk accesses, so that here we sort
1356 * the glocks by number (i.e. disk location of the inodes) so that if
1357 * there are any such accesses, they'll be sent in order (mostly).
1358 *
1359 * Must be called under the lru_lock, but may drop and retake this
1360 * lock. While the lru_lock is dropped, entries may vanish from the
1361 * list, but no new entries will appear on the list (since it is
1362 * private)
1363 */
1364
1365 static void gfs2_dispose_glock_lru(struct list_head *list)
1366 __releases(&lru_lock)
1367 __acquires(&lru_lock)
1368 {
1369 struct gfs2_glock *gl;
1370
1371 list_sort(NULL, list, glock_cmp);
1372
1373 while(!list_empty(list)) {
1374 gl = list_entry(list->next, struct gfs2_glock, gl_lru);
1375 list_del_init(&gl->gl_lru);
1376 if (!spin_trylock(&gl->gl_spin)) {
1377 add_back_to_lru:
1378 list_add(&gl->gl_lru, &lru_list);
1379 atomic_inc(&lru_count);
1380 continue;
1381 }
1382 if (test_and_set_bit(GLF_LOCK, &gl->gl_flags)) {
1383 spin_unlock(&gl->gl_spin);
1384 goto add_back_to_lru;
1385 }
1386 clear_bit(GLF_LRU, &gl->gl_flags);
1387 gl->gl_lockref.count++;
1388 if (demote_ok(gl))
1389 handle_callback(gl, LM_ST_UNLOCKED, 0, false);
1390 WARN_ON(!test_and_clear_bit(GLF_LOCK, &gl->gl_flags));
1391 if (queue_delayed_work(glock_workqueue, &gl->gl_work, 0) == 0)
1392 gl->gl_lockref.count--;
1393 spin_unlock(&gl->gl_spin);
1394 cond_resched_lock(&lru_lock);
1395 }
1396 }
1397
1398 /**
1399 * gfs2_scan_glock_lru - Scan the LRU looking for locks to demote
1400 * @nr: The number of entries to scan
1401 *
1402 * This function selects the entries on the LRU which are able to
1403 * be demoted, and then kicks off the process by calling
1404 * gfs2_dispose_glock_lru() above.
1405 */
1406
1407 static long gfs2_scan_glock_lru(int nr)
1408 {
1409 struct gfs2_glock *gl;
1410 LIST_HEAD(skipped);
1411 LIST_HEAD(dispose);
1412 long freed = 0;
1413
1414 spin_lock(&lru_lock);
1415 while ((nr-- >= 0) && !list_empty(&lru_list)) {
1416 gl = list_entry(lru_list.next, struct gfs2_glock, gl_lru);
1417
1418 /* Test for being demotable */
1419 if (!test_bit(GLF_LOCK, &gl->gl_flags)) {
1420 list_move(&gl->gl_lru, &dispose);
1421 atomic_dec(&lru_count);
1422 freed++;
1423 continue;
1424 }
1425
1426 list_move(&gl->gl_lru, &skipped);
1427 }
1428 list_splice(&skipped, &lru_list);
1429 if (!list_empty(&dispose))
1430 gfs2_dispose_glock_lru(&dispose);
1431 spin_unlock(&lru_lock);
1432
1433 return freed;
1434 }
1435
1436 static unsigned long gfs2_glock_shrink_scan(struct shrinker *shrink,
1437 struct shrink_control *sc)
1438 {
1439 if (!(sc->gfp_mask & __GFP_FS))
1440 return SHRINK_STOP;
1441 return gfs2_scan_glock_lru(sc->nr_to_scan);
1442 }
1443
1444 static unsigned long gfs2_glock_shrink_count(struct shrinker *shrink,
1445 struct shrink_control *sc)
1446 {
1447 return vfs_pressure_ratio(atomic_read(&lru_count));
1448 }
1449
1450 static struct shrinker glock_shrinker = {
1451 .seeks = DEFAULT_SEEKS,
1452 .count_objects = gfs2_glock_shrink_count,
1453 .scan_objects = gfs2_glock_shrink_scan,
1454 };
1455
1456 /**
1457 * examine_bucket - Call a function for glock in a hash bucket
1458 * @examiner: the function
1459 * @sdp: the filesystem
1460 * @bucket: the bucket
1461 *
1462 */
1463
1464 static void examine_bucket(glock_examiner examiner, const struct gfs2_sbd *sdp,
1465 unsigned int hash)
1466 {
1467 struct gfs2_glock *gl;
1468 struct hlist_bl_head *head = &gl_hash_table[hash];
1469 struct hlist_bl_node *pos;
1470
1471 rcu_read_lock();
1472 hlist_bl_for_each_entry_rcu(gl, pos, head, gl_list) {
1473 if ((gl->gl_sbd == sdp) && lockref_get_not_dead(&gl->gl_lockref))
1474 examiner(gl);
1475 }
1476 rcu_read_unlock();
1477 cond_resched();
1478 }
1479
1480 static void glock_hash_walk(glock_examiner examiner, const struct gfs2_sbd *sdp)
1481 {
1482 unsigned x;
1483
1484 for (x = 0; x < GFS2_GL_HASH_SIZE; x++)
1485 examine_bucket(examiner, sdp, x);
1486 }
1487
1488
1489 /**
1490 * thaw_glock - thaw out a glock which has an unprocessed reply waiting
1491 * @gl: The glock to thaw
1492 *
1493 */
1494
1495 static void thaw_glock(struct gfs2_glock *gl)
1496 {
1497 if (!test_and_clear_bit(GLF_FROZEN, &gl->gl_flags))
1498 goto out;
1499 set_bit(GLF_REPLY_PENDING, &gl->gl_flags);
1500 if (queue_delayed_work(glock_workqueue, &gl->gl_work, 0) == 0) {
1501 out:
1502 gfs2_glock_put(gl);
1503 }
1504 }
1505
1506 /**
1507 * clear_glock - look at a glock and see if we can free it from glock cache
1508 * @gl: the glock to look at
1509 *
1510 */
1511
1512 static void clear_glock(struct gfs2_glock *gl)
1513 {
1514 gfs2_glock_remove_from_lru(gl);
1515
1516 spin_lock(&gl->gl_spin);
1517 if (gl->gl_state != LM_ST_UNLOCKED)
1518 handle_callback(gl, LM_ST_UNLOCKED, 0, false);
1519 spin_unlock(&gl->gl_spin);
1520 if (queue_delayed_work(glock_workqueue, &gl->gl_work, 0) == 0)
1521 gfs2_glock_put(gl);
1522 }
1523
1524 /**
1525 * gfs2_glock_thaw - Thaw any frozen glocks
1526 * @sdp: The super block
1527 *
1528 */
1529
1530 void gfs2_glock_thaw(struct gfs2_sbd *sdp)
1531 {
1532 glock_hash_walk(thaw_glock, sdp);
1533 }
1534
1535 static void dump_glock(struct seq_file *seq, struct gfs2_glock *gl)
1536 {
1537 spin_lock(&gl->gl_spin);
1538 gfs2_dump_glock(seq, gl);
1539 spin_unlock(&gl->gl_spin);
1540 }
1541
1542 static void dump_glock_func(struct gfs2_glock *gl)
1543 {
1544 dump_glock(NULL, gl);
1545 }
1546
1547 /**
1548 * gfs2_gl_hash_clear - Empty out the glock hash table
1549 * @sdp: the filesystem
1550 * @wait: wait until it's all gone
1551 *
1552 * Called when unmounting the filesystem.
1553 */
1554
1555 void gfs2_gl_hash_clear(struct gfs2_sbd *sdp)
1556 {
1557 set_bit(SDF_SKIP_DLM_UNLOCK, &sdp->sd_flags);
1558 flush_workqueue(glock_workqueue);
1559 glock_hash_walk(clear_glock, sdp);
1560 flush_workqueue(glock_workqueue);
1561 wait_event(sdp->sd_glock_wait, atomic_read(&sdp->sd_glock_disposal) == 0);
1562 glock_hash_walk(dump_glock_func, sdp);
1563 }
1564
1565 void gfs2_glock_finish_truncate(struct gfs2_inode *ip)
1566 {
1567 struct gfs2_glock *gl = ip->i_gl;
1568 int ret;
1569
1570 ret = gfs2_truncatei_resume(ip);
1571 gfs2_assert_withdraw(gl->gl_sbd, ret == 0);
1572
1573 spin_lock(&gl->gl_spin);
1574 clear_bit(GLF_LOCK, &gl->gl_flags);
1575 run_queue(gl, 1);
1576 spin_unlock(&gl->gl_spin);
1577 }
1578
1579 static const char *state2str(unsigned state)
1580 {
1581 switch(state) {
1582 case LM_ST_UNLOCKED:
1583 return "UN";
1584 case LM_ST_SHARED:
1585 return "SH";
1586 case LM_ST_DEFERRED:
1587 return "DF";
1588 case LM_ST_EXCLUSIVE:
1589 return "EX";
1590 }
1591 return "??";
1592 }
1593
1594 static const char *hflags2str(char *buf, unsigned flags, unsigned long iflags)
1595 {
1596 char *p = buf;
1597 if (flags & LM_FLAG_TRY)
1598 *p++ = 't';
1599 if (flags & LM_FLAG_TRY_1CB)
1600 *p++ = 'T';
1601 if (flags & LM_FLAG_NOEXP)
1602 *p++ = 'e';
1603 if (flags & LM_FLAG_ANY)
1604 *p++ = 'A';
1605 if (flags & LM_FLAG_PRIORITY)
1606 *p++ = 'p';
1607 if (flags & GL_ASYNC)
1608 *p++ = 'a';
1609 if (flags & GL_EXACT)
1610 *p++ = 'E';
1611 if (flags & GL_NOCACHE)
1612 *p++ = 'c';
1613 if (test_bit(HIF_HOLDER, &iflags))
1614 *p++ = 'H';
1615 if (test_bit(HIF_WAIT, &iflags))
1616 *p++ = 'W';
1617 if (test_bit(HIF_FIRST, &iflags))
1618 *p++ = 'F';
1619 *p = 0;
1620 return buf;
1621 }
1622
1623 /**
1624 * dump_holder - print information about a glock holder
1625 * @seq: the seq_file struct
1626 * @gh: the glock holder
1627 *
1628 */
1629
1630 static void dump_holder(struct seq_file *seq, const struct gfs2_holder *gh)
1631 {
1632 struct task_struct *gh_owner = NULL;
1633 char flags_buf[32];
1634
1635 rcu_read_lock();
1636 if (gh->gh_owner_pid)
1637 gh_owner = pid_task(gh->gh_owner_pid, PIDTYPE_PID);
1638 gfs2_print_dbg(seq, " H: s:%s f:%s e:%d p:%ld [%s] %pS\n",
1639 state2str(gh->gh_state),
1640 hflags2str(flags_buf, gh->gh_flags, gh->gh_iflags),
1641 gh->gh_error,
1642 gh->gh_owner_pid ? (long)pid_nr(gh->gh_owner_pid) : -1,
1643 gh_owner ? gh_owner->comm : "(ended)",
1644 (void *)gh->gh_ip);
1645 rcu_read_unlock();
1646 }
1647
1648 static const char *gflags2str(char *buf, const struct gfs2_glock *gl)
1649 {
1650 const unsigned long *gflags = &gl->gl_flags;
1651 char *p = buf;
1652
1653 if (test_bit(GLF_LOCK, gflags))
1654 *p++ = 'l';
1655 if (test_bit(GLF_DEMOTE, gflags))
1656 *p++ = 'D';
1657 if (test_bit(GLF_PENDING_DEMOTE, gflags))
1658 *p++ = 'd';
1659 if (test_bit(GLF_DEMOTE_IN_PROGRESS, gflags))
1660 *p++ = 'p';
1661 if (test_bit(GLF_DIRTY, gflags))
1662 *p++ = 'y';
1663 if (test_bit(GLF_LFLUSH, gflags))
1664 *p++ = 'f';
1665 if (test_bit(GLF_INVALIDATE_IN_PROGRESS, gflags))
1666 *p++ = 'i';
1667 if (test_bit(GLF_REPLY_PENDING, gflags))
1668 *p++ = 'r';
1669 if (test_bit(GLF_INITIAL, gflags))
1670 *p++ = 'I';
1671 if (test_bit(GLF_FROZEN, gflags))
1672 *p++ = 'F';
1673 if (test_bit(GLF_QUEUED, gflags))
1674 *p++ = 'q';
1675 if (test_bit(GLF_LRU, gflags))
1676 *p++ = 'L';
1677 if (gl->gl_object)
1678 *p++ = 'o';
1679 if (test_bit(GLF_BLOCKING, gflags))
1680 *p++ = 'b';
1681 *p = 0;
1682 return buf;
1683 }
1684
1685 /**
1686 * gfs2_dump_glock - print information about a glock
1687 * @seq: The seq_file struct
1688 * @gl: the glock
1689 *
1690 * The file format is as follows:
1691 * One line per object, capital letters are used to indicate objects
1692 * G = glock, I = Inode, R = rgrp, H = holder. Glocks are not indented,
1693 * other objects are indented by a single space and follow the glock to
1694 * which they are related. Fields are indicated by lower case letters
1695 * followed by a colon and the field value, except for strings which are in
1696 * [] so that its possible to see if they are composed of spaces for
1697 * example. The field's are n = number (id of the object), f = flags,
1698 * t = type, s = state, r = refcount, e = error, p = pid.
1699 *
1700 */
1701
1702 void gfs2_dump_glock(struct seq_file *seq, const struct gfs2_glock *gl)
1703 {
1704 const struct gfs2_glock_operations *glops = gl->gl_ops;
1705 unsigned long long dtime;
1706 const struct gfs2_holder *gh;
1707 char gflags_buf[32];
1708
1709 dtime = jiffies - gl->gl_demote_time;
1710 dtime *= 1000000/HZ; /* demote time in uSec */
1711 if (!test_bit(GLF_DEMOTE, &gl->gl_flags))
1712 dtime = 0;
1713 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",
1714 state2str(gl->gl_state),
1715 gl->gl_name.ln_type,
1716 (unsigned long long)gl->gl_name.ln_number,
1717 gflags2str(gflags_buf, gl),
1718 state2str(gl->gl_target),
1719 state2str(gl->gl_demote_state), dtime,
1720 atomic_read(&gl->gl_ail_count),
1721 atomic_read(&gl->gl_revokes),
1722 (int)gl->gl_lockref.count, gl->gl_hold_time);
1723
1724 list_for_each_entry(gh, &gl->gl_holders, gh_list)
1725 dump_holder(seq, gh);
1726
1727 if (gl->gl_state != LM_ST_UNLOCKED && glops->go_dump)
1728 glops->go_dump(seq, gl);
1729 }
1730
1731 static int gfs2_glstats_seq_show(struct seq_file *seq, void *iter_ptr)
1732 {
1733 struct gfs2_glock *gl = iter_ptr;
1734
1735 seq_printf(seq, "G: n:%u/%llx rtt:%lld/%lld rttb:%lld/%lld irt:%lld/%lld dcnt: %lld qcnt: %lld\n",
1736 gl->gl_name.ln_type,
1737 (unsigned long long)gl->gl_name.ln_number,
1738 (long long)gl->gl_stats.stats[GFS2_LKS_SRTT],
1739 (long long)gl->gl_stats.stats[GFS2_LKS_SRTTVAR],
1740 (long long)gl->gl_stats.stats[GFS2_LKS_SRTTB],
1741 (long long)gl->gl_stats.stats[GFS2_LKS_SRTTVARB],
1742 (long long)gl->gl_stats.stats[GFS2_LKS_SIRT],
1743 (long long)gl->gl_stats.stats[GFS2_LKS_SIRTVAR],
1744 (long long)gl->gl_stats.stats[GFS2_LKS_DCOUNT],
1745 (long long)gl->gl_stats.stats[GFS2_LKS_QCOUNT]);
1746 return 0;
1747 }
1748
1749 static const char *gfs2_gltype[] = {
1750 "type",
1751 "reserved",
1752 "nondisk",
1753 "inode",
1754 "rgrp",
1755 "meta",
1756 "iopen",
1757 "flock",
1758 "plock",
1759 "quota",
1760 "journal",
1761 };
1762
1763 static const char *gfs2_stype[] = {
1764 [GFS2_LKS_SRTT] = "srtt",
1765 [GFS2_LKS_SRTTVAR] = "srttvar",
1766 [GFS2_LKS_SRTTB] = "srttb",
1767 [GFS2_LKS_SRTTVARB] = "srttvarb",
1768 [GFS2_LKS_SIRT] = "sirt",
1769 [GFS2_LKS_SIRTVAR] = "sirtvar",
1770 [GFS2_LKS_DCOUNT] = "dlm",
1771 [GFS2_LKS_QCOUNT] = "queue",
1772 };
1773
1774 #define GFS2_NR_SBSTATS (ARRAY_SIZE(gfs2_gltype) * ARRAY_SIZE(gfs2_stype))
1775
1776 static int gfs2_sbstats_seq_show(struct seq_file *seq, void *iter_ptr)
1777 {
1778 struct gfs2_glock_iter *gi = seq->private;
1779 struct gfs2_sbd *sdp = gi->sdp;
1780 unsigned index = gi->hash >> 3;
1781 unsigned subindex = gi->hash & 0x07;
1782 s64 value;
1783 int i;
1784
1785 if (index == 0 && subindex != 0)
1786 return 0;
1787
1788 seq_printf(seq, "%-10s %8s:", gfs2_gltype[index],
1789 (index == 0) ? "cpu": gfs2_stype[subindex]);
1790
1791 for_each_possible_cpu(i) {
1792 const struct gfs2_pcpu_lkstats *lkstats = per_cpu_ptr(sdp->sd_lkstats, i);
1793 if (index == 0) {
1794 value = i;
1795 } else {
1796 value = lkstats->lkstats[index - 1].stats[subindex];
1797 }
1798 seq_printf(seq, " %15lld", (long long)value);
1799 }
1800 seq_putc(seq, '\n');
1801 return 0;
1802 }
1803
1804 int __init gfs2_glock_init(void)
1805 {
1806 unsigned i;
1807 for(i = 0; i < GFS2_GL_HASH_SIZE; i++) {
1808 INIT_HLIST_BL_HEAD(&gl_hash_table[i]);
1809 }
1810
1811 glock_workqueue = alloc_workqueue("glock_workqueue", WQ_MEM_RECLAIM |
1812 WQ_HIGHPRI | WQ_FREEZABLE, 0);
1813 if (!glock_workqueue)
1814 return -ENOMEM;
1815 gfs2_delete_workqueue = alloc_workqueue("delete_workqueue",
1816 WQ_MEM_RECLAIM | WQ_FREEZABLE,
1817 0);
1818 if (!gfs2_delete_workqueue) {
1819 destroy_workqueue(glock_workqueue);
1820 return -ENOMEM;
1821 }
1822
1823 register_shrinker(&glock_shrinker);
1824
1825 return 0;
1826 }
1827
1828 void gfs2_glock_exit(void)
1829 {
1830 unregister_shrinker(&glock_shrinker);
1831 destroy_workqueue(glock_workqueue);
1832 destroy_workqueue(gfs2_delete_workqueue);
1833 }
1834
1835 static inline struct gfs2_glock *glock_hash_chain(unsigned hash)
1836 {
1837 return hlist_bl_entry(hlist_bl_first_rcu(&gl_hash_table[hash]),
1838 struct gfs2_glock, gl_list);
1839 }
1840
1841 static inline struct gfs2_glock *glock_hash_next(struct gfs2_glock *gl)
1842 {
1843 return hlist_bl_entry(rcu_dereference(gl->gl_list.next),
1844 struct gfs2_glock, gl_list);
1845 }
1846
1847 static int gfs2_glock_iter_next(struct gfs2_glock_iter *gi)
1848 {
1849 struct gfs2_glock *gl;
1850
1851 do {
1852 gl = gi->gl;
1853 if (gl) {
1854 gi->gl = glock_hash_next(gl);
1855 gi->nhash++;
1856 } else {
1857 if (gi->hash >= GFS2_GL_HASH_SIZE) {
1858 rcu_read_unlock();
1859 return 1;
1860 }
1861 gi->gl = glock_hash_chain(gi->hash);
1862 gi->nhash = 0;
1863 }
1864 while (gi->gl == NULL) {
1865 gi->hash++;
1866 if (gi->hash >= GFS2_GL_HASH_SIZE) {
1867 rcu_read_unlock();
1868 return 1;
1869 }
1870 gi->gl = glock_hash_chain(gi->hash);
1871 gi->nhash = 0;
1872 }
1873 /* Skip entries for other sb and dead entries */
1874 } while (gi->sdp != gi->gl->gl_sbd ||
1875 __lockref_is_dead(&gi->gl->gl_lockref));
1876
1877 return 0;
1878 }
1879
1880 static void *gfs2_glock_seq_start(struct seq_file *seq, loff_t *pos)
1881 {
1882 struct gfs2_glock_iter *gi = seq->private;
1883 loff_t n = *pos;
1884
1885 if (gi->last_pos <= *pos)
1886 n = gi->nhash + (*pos - gi->last_pos);
1887 else
1888 gi->hash = 0;
1889
1890 gi->nhash = 0;
1891 rcu_read_lock();
1892
1893 do {
1894 if (gfs2_glock_iter_next(gi))
1895 return NULL;
1896 } while (n--);
1897
1898 gi->last_pos = *pos;
1899 return gi->gl;
1900 }
1901
1902 static void *gfs2_glock_seq_next(struct seq_file *seq, void *iter_ptr,
1903 loff_t *pos)
1904 {
1905 struct gfs2_glock_iter *gi = seq->private;
1906
1907 (*pos)++;
1908 gi->last_pos = *pos;
1909 if (gfs2_glock_iter_next(gi))
1910 return NULL;
1911
1912 return gi->gl;
1913 }
1914
1915 static void gfs2_glock_seq_stop(struct seq_file *seq, void *iter_ptr)
1916 {
1917 struct gfs2_glock_iter *gi = seq->private;
1918
1919 if (gi->gl)
1920 rcu_read_unlock();
1921 gi->gl = NULL;
1922 }
1923
1924 static int gfs2_glock_seq_show(struct seq_file *seq, void *iter_ptr)
1925 {
1926 dump_glock(seq, iter_ptr);
1927 return 0;
1928 }
1929
1930 static void *gfs2_sbstats_seq_start(struct seq_file *seq, loff_t *pos)
1931 {
1932 struct gfs2_glock_iter *gi = seq->private;
1933
1934 gi->hash = *pos;
1935 if (*pos >= GFS2_NR_SBSTATS)
1936 return NULL;
1937 preempt_disable();
1938 return SEQ_START_TOKEN;
1939 }
1940
1941 static void *gfs2_sbstats_seq_next(struct seq_file *seq, void *iter_ptr,
1942 loff_t *pos)
1943 {
1944 struct gfs2_glock_iter *gi = seq->private;
1945 (*pos)++;
1946 gi->hash++;
1947 if (gi->hash >= GFS2_NR_SBSTATS) {
1948 preempt_enable();
1949 return NULL;
1950 }
1951 return SEQ_START_TOKEN;
1952 }
1953
1954 static void gfs2_sbstats_seq_stop(struct seq_file *seq, void *iter_ptr)
1955 {
1956 preempt_enable();
1957 }
1958
1959 static const struct seq_operations gfs2_glock_seq_ops = {
1960 .start = gfs2_glock_seq_start,
1961 .next = gfs2_glock_seq_next,
1962 .stop = gfs2_glock_seq_stop,
1963 .show = gfs2_glock_seq_show,
1964 };
1965
1966 static const struct seq_operations gfs2_glstats_seq_ops = {
1967 .start = gfs2_glock_seq_start,
1968 .next = gfs2_glock_seq_next,
1969 .stop = gfs2_glock_seq_stop,
1970 .show = gfs2_glstats_seq_show,
1971 };
1972
1973 static const struct seq_operations gfs2_sbstats_seq_ops = {
1974 .start = gfs2_sbstats_seq_start,
1975 .next = gfs2_sbstats_seq_next,
1976 .stop = gfs2_sbstats_seq_stop,
1977 .show = gfs2_sbstats_seq_show,
1978 };
1979
1980 #define GFS2_SEQ_GOODSIZE min(PAGE_SIZE << PAGE_ALLOC_COSTLY_ORDER, 65536UL)
1981
1982 static int gfs2_glocks_open(struct inode *inode, struct file *file)
1983 {
1984 int ret = seq_open_private(file, &gfs2_glock_seq_ops,
1985 sizeof(struct gfs2_glock_iter));
1986 if (ret == 0) {
1987 struct seq_file *seq = file->private_data;
1988 struct gfs2_glock_iter *gi = seq->private;
1989 gi->sdp = inode->i_private;
1990 seq->buf = kmalloc(GFS2_SEQ_GOODSIZE, GFP_KERNEL | __GFP_NOWARN);
1991 if (seq->buf)
1992 seq->size = GFS2_SEQ_GOODSIZE;
1993 }
1994 return ret;
1995 }
1996
1997 static int gfs2_glstats_open(struct inode *inode, struct file *file)
1998 {
1999 int ret = seq_open_private(file, &gfs2_glstats_seq_ops,
2000 sizeof(struct gfs2_glock_iter));
2001 if (ret == 0) {
2002 struct seq_file *seq = file->private_data;
2003 struct gfs2_glock_iter *gi = seq->private;
2004 gi->sdp = inode->i_private;
2005 seq->buf = kmalloc(GFS2_SEQ_GOODSIZE, GFP_KERNEL | __GFP_NOWARN);
2006 if (seq->buf)
2007 seq->size = GFS2_SEQ_GOODSIZE;
2008 }
2009 return ret;
2010 }
2011
2012 static int gfs2_sbstats_open(struct inode *inode, struct file *file)
2013 {
2014 int ret = seq_open_private(file, &gfs2_sbstats_seq_ops,
2015 sizeof(struct gfs2_glock_iter));
2016 if (ret == 0) {
2017 struct seq_file *seq = file->private_data;
2018 struct gfs2_glock_iter *gi = seq->private;
2019 gi->sdp = inode->i_private;
2020 }
2021 return ret;
2022 }
2023
2024 static const struct file_operations gfs2_glocks_fops = {
2025 .owner = THIS_MODULE,
2026 .open = gfs2_glocks_open,
2027 .read = seq_read,
2028 .llseek = seq_lseek,
2029 .release = seq_release_private,
2030 };
2031
2032 static const struct file_operations gfs2_glstats_fops = {
2033 .owner = THIS_MODULE,
2034 .open = gfs2_glstats_open,
2035 .read = seq_read,
2036 .llseek = seq_lseek,
2037 .release = seq_release_private,
2038 };
2039
2040 static const struct file_operations gfs2_sbstats_fops = {
2041 .owner = THIS_MODULE,
2042 .open = gfs2_sbstats_open,
2043 .read = seq_read,
2044 .llseek = seq_lseek,
2045 .release = seq_release_private,
2046 };
2047
2048 int gfs2_create_debugfs_file(struct gfs2_sbd *sdp)
2049 {
2050 struct dentry *dent;
2051
2052 dent = debugfs_create_dir(sdp->sd_table_name, gfs2_root);
2053 if (IS_ERR_OR_NULL(dent))
2054 goto fail;
2055 sdp->debugfs_dir = dent;
2056
2057 dent = debugfs_create_file("glocks",
2058 S_IFREG | S_IRUGO,
2059 sdp->debugfs_dir, sdp,
2060 &gfs2_glocks_fops);
2061 if (IS_ERR_OR_NULL(dent))
2062 goto fail;
2063 sdp->debugfs_dentry_glocks = dent;
2064
2065 dent = debugfs_create_file("glstats",
2066 S_IFREG | S_IRUGO,
2067 sdp->debugfs_dir, sdp,
2068 &gfs2_glstats_fops);
2069 if (IS_ERR_OR_NULL(dent))
2070 goto fail;
2071 sdp->debugfs_dentry_glstats = dent;
2072
2073 dent = debugfs_create_file("sbstats",
2074 S_IFREG | S_IRUGO,
2075 sdp->debugfs_dir, sdp,
2076 &gfs2_sbstats_fops);
2077 if (IS_ERR_OR_NULL(dent))
2078 goto fail;
2079 sdp->debugfs_dentry_sbstats = dent;
2080
2081 return 0;
2082 fail:
2083 gfs2_delete_debugfs_file(sdp);
2084 return dent ? PTR_ERR(dent) : -ENOMEM;
2085 }
2086
2087 void gfs2_delete_debugfs_file(struct gfs2_sbd *sdp)
2088 {
2089 if (sdp->debugfs_dir) {
2090 if (sdp->debugfs_dentry_glocks) {
2091 debugfs_remove(sdp->debugfs_dentry_glocks);
2092 sdp->debugfs_dentry_glocks = NULL;
2093 }
2094 if (sdp->debugfs_dentry_glstats) {
2095 debugfs_remove(sdp->debugfs_dentry_glstats);
2096 sdp->debugfs_dentry_glstats = NULL;
2097 }
2098 if (sdp->debugfs_dentry_sbstats) {
2099 debugfs_remove(sdp->debugfs_dentry_sbstats);
2100 sdp->debugfs_dentry_sbstats = NULL;
2101 }
2102 debugfs_remove(sdp->debugfs_dir);
2103 sdp->debugfs_dir = NULL;
2104 }
2105 }
2106
2107 int gfs2_register_debugfs(void)
2108 {
2109 gfs2_root = debugfs_create_dir("gfs2", NULL);
2110 if (IS_ERR(gfs2_root))
2111 return PTR_ERR(gfs2_root);
2112 return gfs2_root ? 0 : -ENOMEM;
2113 }
2114
2115 void gfs2_unregister_debugfs(void)
2116 {
2117 debugfs_remove(gfs2_root);
2118 gfs2_root = NULL;
2119 }
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