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mm/hmm.c: remove superfluous RCU protection around radix tree lookup
[linux/fpc-iii.git] / fs / gfs2 / glock.c
blob82fb5583445ca43f80d61ec3a7ac2fb0e006ef81
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/hash.h>
19 #include <linux/jhash.h>
20 #include <linux/kallsyms.h>
21 #include <linux/gfs2_ondisk.h>
22 #include <linux/list.h>
23 #include <linux/wait.h>
24 #include <linux/module.h>
25 #include <linux/uaccess.h>
26 #include <linux/seq_file.h>
27 #include <linux/debugfs.h>
28 #include <linux/kthread.h>
29 #include <linux/freezer.h>
30 #include <linux/workqueue.h>
31 #include <linux/jiffies.h>
32 #include <linux/rcupdate.h>
33 #include <linux/rculist_bl.h>
34 #include <linux/bit_spinlock.h>
35 #include <linux/percpu.h>
36 #include <linux/list_sort.h>
37 #include <linux/lockref.h>
38 #include <linux/rhashtable.h>
39
40 #include "gfs2.h"
41 #include "incore.h"
42 #include "glock.h"
43 #include "glops.h"
44 #include "inode.h"
45 #include "lops.h"
46 #include "meta_io.h"
47 #include "quota.h"
48 #include "super.h"
49 #include "util.h"
50 #include "bmap.h"
51 #define CREATE_TRACE_POINTS
52 #include "trace_gfs2.h"
53
54 struct gfs2_glock_iter {
55 struct gfs2_sbd *sdp; /* incore superblock */
56 struct rhashtable_iter hti; /* rhashtable iterator */
57 struct gfs2_glock *gl; /* current glock struct */
58 loff_t last_pos; /* last position */
59 };
60
61 typedef void (*glock_examiner) (struct gfs2_glock * gl);
62
63 static void do_xmote(struct gfs2_glock *gl, struct gfs2_holder *gh, unsigned int target);
64
65 static struct dentry *gfs2_root;
66 static struct workqueue_struct *glock_workqueue;
67 struct workqueue_struct *gfs2_delete_workqueue;
68 static LIST_HEAD(lru_list);
69 static atomic_t lru_count = ATOMIC_INIT(0);
70 static DEFINE_SPINLOCK(lru_lock);
71
72 #define GFS2_GL_HASH_SHIFT 15
73 #define GFS2_GL_HASH_SIZE BIT(GFS2_GL_HASH_SHIFT)
74
75 static const struct rhashtable_params ht_parms = {
76 .nelem_hint = GFS2_GL_HASH_SIZE * 3 / 4,
77 .key_len = offsetofend(struct lm_lockname, ln_type),
78 .key_offset = offsetof(struct gfs2_glock, gl_name),
79 .head_offset = offsetof(struct gfs2_glock, gl_node),
80 };
81
82 static struct rhashtable gl_hash_table;
83
84 #define GLOCK_WAIT_TABLE_BITS 12
85 #define GLOCK_WAIT_TABLE_SIZE (1 << GLOCK_WAIT_TABLE_BITS)
86 static wait_queue_head_t glock_wait_table[GLOCK_WAIT_TABLE_SIZE] __cacheline_aligned;
87
88 struct wait_glock_queue {
89 struct lm_lockname *name;
90 wait_queue_entry_t wait;
91 };
92
93 static int glock_wake_function(wait_queue_entry_t *wait, unsigned int mode,
94 int sync, void *key)
95 {
96 struct wait_glock_queue *wait_glock =
97 container_of(wait, struct wait_glock_queue, wait);
98 struct lm_lockname *wait_name = wait_glock->name;
99 struct lm_lockname *wake_name = key;
100
101 if (wake_name->ln_sbd != wait_name->ln_sbd ||
102 wake_name->ln_number != wait_name->ln_number ||
103 wake_name->ln_type != wait_name->ln_type)
104 return 0;
105 return autoremove_wake_function(wait, mode, sync, key);
106 }
107
108 static wait_queue_head_t *glock_waitqueue(struct lm_lockname *name)
109 {
110 u32 hash = jhash2((u32 *)name, sizeof(*name) / 4, 0);
111
112 return glock_wait_table + hash_32(hash, GLOCK_WAIT_TABLE_BITS);
113 }
114
115 /**
116 * wake_up_glock - Wake up waiters on a glock
117 * @gl: the glock
118 */
119 static void wake_up_glock(struct gfs2_glock *gl)
120 {
121 wait_queue_head_t *wq = glock_waitqueue(&gl->gl_name);
122
123 if (waitqueue_active(wq))
124 __wake_up(wq, TASK_NORMAL, 1, &gl->gl_name);
125 }
126
127 static void gfs2_glock_dealloc(struct rcu_head *rcu)
128 {
129 struct gfs2_glock *gl = container_of(rcu, struct gfs2_glock, gl_rcu);
130
131 if (gl->gl_ops->go_flags & GLOF_ASPACE) {
132 kmem_cache_free(gfs2_glock_aspace_cachep, gl);
133 } else {
134 kfree(gl->gl_lksb.sb_lvbptr);
135 kmem_cache_free(gfs2_glock_cachep, gl);
136 }
137 }
138
139 void gfs2_glock_free(struct gfs2_glock *gl)
140 {
141 struct gfs2_sbd *sdp = gl->gl_name.ln_sbd;
142
143 rhashtable_remove_fast(&gl_hash_table, &gl->gl_node, ht_parms);
144 smp_mb();
145 wake_up_glock(gl);
146 call_rcu(&gl->gl_rcu, gfs2_glock_dealloc);
147 if (atomic_dec_and_test(&sdp->sd_glock_disposal))
148 wake_up(&sdp->sd_glock_wait);
149 }
150
151 /**
152 * gfs2_glock_hold() - increment reference count on glock
153 * @gl: The glock to hold
154 *
155 */
156
157 void gfs2_glock_hold(struct gfs2_glock *gl)
158 {
159 GLOCK_BUG_ON(gl, __lockref_is_dead(&gl->gl_lockref));
160 lockref_get(&gl->gl_lockref);
161 }
162
163 /**
164 * demote_ok - Check to see if it's ok to unlock a glock
165 * @gl: the glock
166 *
167 * Returns: 1 if it's ok
168 */
169
170 static int demote_ok(const struct gfs2_glock *gl)
171 {
172 const struct gfs2_glock_operations *glops = gl->gl_ops;
173
174 if (gl->gl_state == LM_ST_UNLOCKED)
175 return 0;
176 if (!list_empty(&gl->gl_holders))
177 return 0;
178 if (glops->go_demote_ok)
179 return glops->go_demote_ok(gl);
180 return 1;
181 }
182
183
184 void gfs2_glock_add_to_lru(struct gfs2_glock *gl)
185 {
186 spin_lock(&lru_lock);
187
188 if (!list_empty(&gl->gl_lru))
189 list_del_init(&gl->gl_lru);
190 else
191 atomic_inc(&lru_count);
192
193 list_add_tail(&gl->gl_lru, &lru_list);
194 set_bit(GLF_LRU, &gl->gl_flags);
195 spin_unlock(&lru_lock);
196 }
197
198 static void gfs2_glock_remove_from_lru(struct gfs2_glock *gl)
199 {
200 if (!(gl->gl_ops->go_flags & GLOF_LRU))
201 return;
202
203 spin_lock(&lru_lock);
204 if (!list_empty(&gl->gl_lru)) {
205 list_del_init(&gl->gl_lru);
206 atomic_dec(&lru_count);
207 clear_bit(GLF_LRU, &gl->gl_flags);
208 }
209 spin_unlock(&lru_lock);
210 }
211
212 /*
213 * Enqueue the glock on the work queue. Passes one glock reference on to the
214 * work queue.
215 */
216 static void __gfs2_glock_queue_work(struct gfs2_glock *gl, unsigned long delay) {
217 if (!queue_delayed_work(glock_workqueue, &gl->gl_work, delay)) {
218 /*
219 * We are holding the lockref spinlock, and the work was still
220 * queued above. The queued work (glock_work_func) takes that
221 * spinlock before dropping its glock reference(s), so it
222 * cannot have dropped them in the meantime.
223 */
224 GLOCK_BUG_ON(gl, gl->gl_lockref.count < 2);
225 gl->gl_lockref.count--;
226 }
227 }
228
229 static void gfs2_glock_queue_work(struct gfs2_glock *gl, unsigned long delay) {
230 spin_lock(&gl->gl_lockref.lock);
231 __gfs2_glock_queue_work(gl, delay);
232 spin_unlock(&gl->gl_lockref.lock);
233 }
234
235 static void __gfs2_glock_put(struct gfs2_glock *gl)
236 {
237 struct gfs2_sbd *sdp = gl->gl_name.ln_sbd;
238 struct address_space *mapping = gfs2_glock2aspace(gl);
239
240 lockref_mark_dead(&gl->gl_lockref);
241
242 gfs2_glock_remove_from_lru(gl);
243 spin_unlock(&gl->gl_lockref.lock);
244 GLOCK_BUG_ON(gl, !list_empty(&gl->gl_holders));
245 GLOCK_BUG_ON(gl, mapping && mapping->nrpages);
246 trace_gfs2_glock_put(gl);
247 sdp->sd_lockstruct.ls_ops->lm_put_lock(gl);
248 }
249
250 /*
251 * Cause the glock to be put in work queue context.
252 */
253 void gfs2_glock_queue_put(struct gfs2_glock *gl)
254 {
255 gfs2_glock_queue_work(gl, 0);
256 }
257
258 /**
259 * gfs2_glock_put() - Decrement reference count on glock
260 * @gl: The glock to put
261 *
262 */
263
264 void gfs2_glock_put(struct gfs2_glock *gl)
265 {
266 if (lockref_put_or_lock(&gl->gl_lockref))
267 return;
268
269 __gfs2_glock_put(gl);
270 }
271
272 /**
273 * may_grant - check if its ok to grant a new lock
274 * @gl: The glock
275 * @gh: The lock request which we wish to grant
276 *
277 * Returns: true if its ok to grant the lock
278 */
279
280 static inline int may_grant(const struct gfs2_glock *gl, const struct gfs2_holder *gh)
281 {
282 const struct gfs2_holder *gh_head = list_entry(gl->gl_holders.next, const struct gfs2_holder, gh_list);
283 if ((gh->gh_state == LM_ST_EXCLUSIVE ||
284 gh_head->gh_state == LM_ST_EXCLUSIVE) && gh != gh_head)
285 return 0;
286 if (gl->gl_state == gh->gh_state)
287 return 1;
288 if (gh->gh_flags & GL_EXACT)
289 return 0;
290 if (gl->gl_state == LM_ST_EXCLUSIVE) {
291 if (gh->gh_state == LM_ST_SHARED && gh_head->gh_state == LM_ST_SHARED)
292 return 1;
293 if (gh->gh_state == LM_ST_DEFERRED && gh_head->gh_state == LM_ST_DEFERRED)
294 return 1;
295 }
296 if (gl->gl_state != LM_ST_UNLOCKED && (gh->gh_flags & LM_FLAG_ANY))
297 return 1;
298 return 0;
299 }
300
301 static void gfs2_holder_wake(struct gfs2_holder *gh)
302 {
303 clear_bit(HIF_WAIT, &gh->gh_iflags);
304 smp_mb__after_atomic();
305 wake_up_bit(&gh->gh_iflags, HIF_WAIT);
306 }
307
308 /**
309 * do_error - Something unexpected has happened during a lock request
310 *
311 */
312
313 static void do_error(struct gfs2_glock *gl, const int ret)
314 {
315 struct gfs2_holder *gh, *tmp;
316
317 list_for_each_entry_safe(gh, tmp, &gl->gl_holders, gh_list) {
318 if (test_bit(HIF_HOLDER, &gh->gh_iflags))
319 continue;
320 if (ret & LM_OUT_ERROR)
321 gh->gh_error = -EIO;
322 else if (gh->gh_flags & (LM_FLAG_TRY | LM_FLAG_TRY_1CB))
323 gh->gh_error = GLR_TRYFAILED;
324 else
325 continue;
326 list_del_init(&gh->gh_list);
327 trace_gfs2_glock_queue(gh, 0);
328 gfs2_holder_wake(gh);
329 }
330 }
331
332 /**
333 * do_promote - promote as many requests as possible on the current queue
334 * @gl: The glock
335 *
336 * Returns: 1 if there is a blocked holder at the head of the list, or 2
337 * if a type specific operation is underway.
338 */
339
340 static int do_promote(struct gfs2_glock *gl)
341 __releases(&gl->gl_lockref.lock)
342 __acquires(&gl->gl_lockref.lock)
343 {
344 const struct gfs2_glock_operations *glops = gl->gl_ops;
345 struct gfs2_holder *gh, *tmp;
346 int ret;
347
348 restart:
349 list_for_each_entry_safe(gh, tmp, &gl->gl_holders, gh_list) {
350 if (test_bit(HIF_HOLDER, &gh->gh_iflags))
351 continue;
352 if (may_grant(gl, gh)) {
353 if (gh->gh_list.prev == &gl->gl_holders &&
354 glops->go_lock) {
355 spin_unlock(&gl->gl_lockref.lock);
356 /* FIXME: eliminate this eventually */
357 ret = glops->go_lock(gh);
358 spin_lock(&gl->gl_lockref.lock);
359 if (ret) {
360 if (ret == 1)
361 return 2;
362 gh->gh_error = ret;
363 list_del_init(&gh->gh_list);
364 trace_gfs2_glock_queue(gh, 0);
365 gfs2_holder_wake(gh);
366 goto restart;
367 }
368 set_bit(HIF_HOLDER, &gh->gh_iflags);
369 trace_gfs2_promote(gh, 1);
370 gfs2_holder_wake(gh);
371 goto restart;
372 }
373 set_bit(HIF_HOLDER, &gh->gh_iflags);
374 trace_gfs2_promote(gh, 0);
375 gfs2_holder_wake(gh);
376 continue;
377 }
378 if (gh->gh_list.prev == &gl->gl_holders)
379 return 1;
380 do_error(gl, 0);
381 break;
382 }
383 return 0;
384 }
385
386 /**
387 * find_first_waiter - find the first gh that's waiting for the glock
388 * @gl: the glock
389 */
390
391 static inline struct gfs2_holder *find_first_waiter(const struct gfs2_glock *gl)
392 {
393 struct gfs2_holder *gh;
394
395 list_for_each_entry(gh, &gl->gl_holders, gh_list) {
396 if (!test_bit(HIF_HOLDER, &gh->gh_iflags))
397 return gh;
398 }
399 return NULL;
400 }
401
402 /**
403 * state_change - record that the glock is now in a different state
404 * @gl: the glock
405 * @new_state the new state
406 *
407 */
408
409 static void state_change(struct gfs2_glock *gl, unsigned int new_state)
410 {
411 int held1, held2;
412
413 held1 = (gl->gl_state != LM_ST_UNLOCKED);
414 held2 = (new_state != LM_ST_UNLOCKED);
415
416 if (held1 != held2) {
417 GLOCK_BUG_ON(gl, __lockref_is_dead(&gl->gl_lockref));
418 if (held2)
419 gl->gl_lockref.count++;
420 else
421 gl->gl_lockref.count--;
422 }
423 if (held1 && held2 && list_empty(&gl->gl_holders))
424 clear_bit(GLF_QUEUED, &gl->gl_flags);
425
426 if (new_state != gl->gl_target)
427 /* shorten our minimum hold time */
428 gl->gl_hold_time = max(gl->gl_hold_time - GL_GLOCK_HOLD_DECR,
429 GL_GLOCK_MIN_HOLD);
430 gl->gl_state = new_state;
431 gl->gl_tchange = jiffies;
432 }
433
434 static void gfs2_demote_wake(struct gfs2_glock *gl)
435 {
436 gl->gl_demote_state = LM_ST_EXCLUSIVE;
437 clear_bit(GLF_DEMOTE, &gl->gl_flags);
438 smp_mb__after_atomic();
439 wake_up_bit(&gl->gl_flags, GLF_DEMOTE);
440 }
441
442 /**
443 * finish_xmote - The DLM has replied to one of our lock requests
444 * @gl: The glock
445 * @ret: The status from the DLM
446 *
447 */
448
449 static void finish_xmote(struct gfs2_glock *gl, unsigned int ret)
450 {
451 const struct gfs2_glock_operations *glops = gl->gl_ops;
452 struct gfs2_holder *gh;
453 unsigned state = ret & LM_OUT_ST_MASK;
454 int rv;
455
456 spin_lock(&gl->gl_lockref.lock);
457 trace_gfs2_glock_state_change(gl, state);
458 state_change(gl, state);
459 gh = find_first_waiter(gl);
460
461 /* Demote to UN request arrived during demote to SH or DF */
462 if (test_bit(GLF_DEMOTE_IN_PROGRESS, &gl->gl_flags) &&
463 state != LM_ST_UNLOCKED && gl->gl_demote_state == LM_ST_UNLOCKED)
464 gl->gl_target = LM_ST_UNLOCKED;
465
466 /* Check for state != intended state */
467 if (unlikely(state != gl->gl_target)) {
468 if (gh && !test_bit(GLF_DEMOTE_IN_PROGRESS, &gl->gl_flags)) {
469 /* move to back of queue and try next entry */
470 if (ret & LM_OUT_CANCELED) {
471 if ((gh->gh_flags & LM_FLAG_PRIORITY) == 0)
472 list_move_tail(&gh->gh_list, &gl->gl_holders);
473 gh = find_first_waiter(gl);
474 gl->gl_target = gh->gh_state;
475 goto retry;
476 }
477 /* Some error or failed "try lock" - report it */
478 if ((ret & LM_OUT_ERROR) ||
479 (gh->gh_flags & (LM_FLAG_TRY | LM_FLAG_TRY_1CB))) {
480 gl->gl_target = gl->gl_state;
481 do_error(gl, ret);
482 goto out;
483 }
484 }
485 switch(state) {
486 /* Unlocked due to conversion deadlock, try again */
487 case LM_ST_UNLOCKED:
488 retry:
489 do_xmote(gl, gh, gl->gl_target);
490 break;
491 /* Conversion fails, unlock and try again */
492 case LM_ST_SHARED:
493 case LM_ST_DEFERRED:
494 do_xmote(gl, gh, LM_ST_UNLOCKED);
495 break;
496 default: /* Everything else */
497 pr_err("wanted %u got %u\n", gl->gl_target, state);
498 GLOCK_BUG_ON(gl, 1);
499 }
500 spin_unlock(&gl->gl_lockref.lock);
501 return;
502 }
503
504 /* Fast path - we got what we asked for */
505 if (test_and_clear_bit(GLF_DEMOTE_IN_PROGRESS, &gl->gl_flags))
506 gfs2_demote_wake(gl);
507 if (state != LM_ST_UNLOCKED) {
508 if (glops->go_xmote_bh) {
509 spin_unlock(&gl->gl_lockref.lock);
510 rv = glops->go_xmote_bh(gl, gh);
511 spin_lock(&gl->gl_lockref.lock);
512 if (rv) {
513 do_error(gl, rv);
514 goto out;
515 }
516 }
517 rv = do_promote(gl);
518 if (rv == 2)
519 goto out_locked;
520 }
521 out:
522 clear_bit(GLF_LOCK, &gl->gl_flags);
523 out_locked:
524 spin_unlock(&gl->gl_lockref.lock);
525 }
526
527 /**
528 * do_xmote - Calls the DLM to change the state of a lock
529 * @gl: The lock state
530 * @gh: The holder (only for promotes)
531 * @target: The target lock state
532 *
533 */
534
535 static void do_xmote(struct gfs2_glock *gl, struct gfs2_holder *gh, unsigned int target)
536 __releases(&gl->gl_lockref.lock)
537 __acquires(&gl->gl_lockref.lock)
538 {
539 const struct gfs2_glock_operations *glops = gl->gl_ops;
540 struct gfs2_sbd *sdp = gl->gl_name.ln_sbd;
541 unsigned int lck_flags = (unsigned int)(gh ? gh->gh_flags : 0);
542 int ret;
543
544 if (unlikely(test_bit(SDF_SHUTDOWN, &sdp->sd_flags)) &&
545 target != LM_ST_UNLOCKED)
546 return;
547 lck_flags &= (LM_FLAG_TRY | LM_FLAG_TRY_1CB | LM_FLAG_NOEXP |
548 LM_FLAG_PRIORITY);
549 GLOCK_BUG_ON(gl, gl->gl_state == target);
550 GLOCK_BUG_ON(gl, gl->gl_state == gl->gl_target);
551 if ((target == LM_ST_UNLOCKED || target == LM_ST_DEFERRED) &&
552 glops->go_inval) {
553 set_bit(GLF_INVALIDATE_IN_PROGRESS, &gl->gl_flags);
554 do_error(gl, 0); /* Fail queued try locks */
555 }
556 gl->gl_req = target;
557 set_bit(GLF_BLOCKING, &gl->gl_flags);
558 if ((gl->gl_req == LM_ST_UNLOCKED) ||
559 (gl->gl_state == LM_ST_EXCLUSIVE) ||
560 (lck_flags & (LM_FLAG_TRY|LM_FLAG_TRY_1CB)))
561 clear_bit(GLF_BLOCKING, &gl->gl_flags);
562 spin_unlock(&gl->gl_lockref.lock);
563 if (glops->go_sync)
564 glops->go_sync(gl);
565 if (test_bit(GLF_INVALIDATE_IN_PROGRESS, &gl->gl_flags))
566 glops->go_inval(gl, target == LM_ST_DEFERRED ? 0 : DIO_METADATA);
567 clear_bit(GLF_INVALIDATE_IN_PROGRESS, &gl->gl_flags);
568
569 gfs2_glock_hold(gl);
570 if (sdp->sd_lockstruct.ls_ops->lm_lock) {
571 /* lock_dlm */
572 ret = sdp->sd_lockstruct.ls_ops->lm_lock(gl, target, lck_flags);
573 if (ret == -EINVAL && gl->gl_target == LM_ST_UNLOCKED &&
574 target == LM_ST_UNLOCKED &&
575 test_bit(SDF_SKIP_DLM_UNLOCK, &sdp->sd_flags)) {
576 finish_xmote(gl, target);
577 gfs2_glock_queue_work(gl, 0);
578 }
579 else if (ret) {
580 pr_err("lm_lock ret %d\n", ret);
581 GLOCK_BUG_ON(gl, !test_bit(SDF_SHUTDOWN,
582 &sdp->sd_flags));
583 }
584 } else { /* lock_nolock */
585 finish_xmote(gl, target);
586 gfs2_glock_queue_work(gl, 0);
587 }
588
589 spin_lock(&gl->gl_lockref.lock);
590 }
591
592 /**
593 * find_first_holder - find the first "holder" gh
594 * @gl: the glock
595 */
596
597 static inline struct gfs2_holder *find_first_holder(const struct gfs2_glock *gl)
598 {
599 struct gfs2_holder *gh;
600
601 if (!list_empty(&gl->gl_holders)) {
602 gh = list_entry(gl->gl_holders.next, struct gfs2_holder, gh_list);
603 if (test_bit(HIF_HOLDER, &gh->gh_iflags))
604 return gh;
605 }
606 return NULL;
607 }
608
609 /**
610 * run_queue - do all outstanding tasks related to a glock
611 * @gl: The glock in question
612 * @nonblock: True if we must not block in run_queue
613 *
614 */
615
616 static void run_queue(struct gfs2_glock *gl, const int nonblock)
617 __releases(&gl->gl_lockref.lock)
618 __acquires(&gl->gl_lockref.lock)
619 {
620 struct gfs2_holder *gh = NULL;
621 int ret;
622
623 if (test_and_set_bit(GLF_LOCK, &gl->gl_flags))
624 return;
625
626 GLOCK_BUG_ON(gl, test_bit(GLF_DEMOTE_IN_PROGRESS, &gl->gl_flags));
627
628 if (test_bit(GLF_DEMOTE, &gl->gl_flags) &&
629 gl->gl_demote_state != gl->gl_state) {
630 if (find_first_holder(gl))
631 goto out_unlock;
632 if (nonblock)
633 goto out_sched;
634 set_bit(GLF_DEMOTE_IN_PROGRESS, &gl->gl_flags);
635 GLOCK_BUG_ON(gl, gl->gl_demote_state == LM_ST_EXCLUSIVE);
636 gl->gl_target = gl->gl_demote_state;
637 } else {
638 if (test_bit(GLF_DEMOTE, &gl->gl_flags))
639 gfs2_demote_wake(gl);
640 ret = do_promote(gl);
641 if (ret == 0)
642 goto out_unlock;
643 if (ret == 2)
644 goto out;
645 gh = find_first_waiter(gl);
646 gl->gl_target = gh->gh_state;
647 if (!(gh->gh_flags & (LM_FLAG_TRY | LM_FLAG_TRY_1CB)))
648 do_error(gl, 0); /* Fail queued try locks */
649 }
650 do_xmote(gl, gh, gl->gl_target);
651 out:
652 return;
653
654 out_sched:
655 clear_bit(GLF_LOCK, &gl->gl_flags);
656 smp_mb__after_atomic();
657 gl->gl_lockref.count++;
658 __gfs2_glock_queue_work(gl, 0);
659 return;
660
661 out_unlock:
662 clear_bit(GLF_LOCK, &gl->gl_flags);
663 smp_mb__after_atomic();
664 return;
665 }
666
667 static void delete_work_func(struct work_struct *work)
668 {
669 struct gfs2_glock *gl = container_of(work, struct gfs2_glock, gl_delete);
670 struct gfs2_sbd *sdp = gl->gl_name.ln_sbd;
671 struct inode *inode;
672 u64 no_addr = gl->gl_name.ln_number;
673
674 /* If someone's using this glock to create a new dinode, the block must
675 have been freed by another node, then re-used, in which case our
676 iopen callback is too late after the fact. Ignore it. */
677 if (test_bit(GLF_INODE_CREATING, &gl->gl_flags))
678 goto out;
679
680 inode = gfs2_lookup_by_inum(sdp, no_addr, NULL, GFS2_BLKST_UNLINKED);
681 if (inode && !IS_ERR(inode)) {
682 d_prune_aliases(inode);
683 iput(inode);
684 }
685 out:
686 gfs2_glock_put(gl);
687 }
688
689 static void glock_work_func(struct work_struct *work)
690 {
691 unsigned long delay = 0;
692 struct gfs2_glock *gl = container_of(work, struct gfs2_glock, gl_work.work);
693 unsigned int drop_refs = 1;
694
695 if (test_and_clear_bit(GLF_REPLY_PENDING, &gl->gl_flags)) {
696 finish_xmote(gl, gl->gl_reply);
697 drop_refs++;
698 }
699 spin_lock(&gl->gl_lockref.lock);
700 if (test_bit(GLF_PENDING_DEMOTE, &gl->gl_flags) &&
701 gl->gl_state != LM_ST_UNLOCKED &&
702 gl->gl_demote_state != LM_ST_EXCLUSIVE) {
703 unsigned long holdtime, now = jiffies;
704
705 holdtime = gl->gl_tchange + gl->gl_hold_time;
706 if (time_before(now, holdtime))
707 delay = holdtime - now;
708
709 if (!delay) {
710 clear_bit(GLF_PENDING_DEMOTE, &gl->gl_flags);
711 set_bit(GLF_DEMOTE, &gl->gl_flags);
712 }
713 }
714 run_queue(gl, 0);
715 if (delay) {
716 /* Keep one glock reference for the work we requeue. */
717 drop_refs--;
718 if (gl->gl_name.ln_type != LM_TYPE_INODE)
719 delay = 0;
720 __gfs2_glock_queue_work(gl, delay);
721 }
722
723 /*
724 * Drop the remaining glock references manually here. (Mind that
725 * __gfs2_glock_queue_work depends on the lockref spinlock begin held
726 * here as well.)
727 */
728 gl->gl_lockref.count -= drop_refs;
729 if (!gl->gl_lockref.count) {
730 __gfs2_glock_put(gl);
731 return;
732 }
733 spin_unlock(&gl->gl_lockref.lock);
734 }
735
736 static struct gfs2_glock *find_insert_glock(struct lm_lockname *name,
737 struct gfs2_glock *new)
738 {
739 struct wait_glock_queue wait;
740 wait_queue_head_t *wq = glock_waitqueue(name);
741 struct gfs2_glock *gl;
742
743 wait.name = name;
744 init_wait(&wait.wait);
745 wait.wait.func = glock_wake_function;
746
747 again:
748 prepare_to_wait(wq, &wait.wait, TASK_UNINTERRUPTIBLE);
749 rcu_read_lock();
750 if (new) {
751 gl = rhashtable_lookup_get_insert_fast(&gl_hash_table,
752 &new->gl_node, ht_parms);
753 if (IS_ERR(gl))
754 goto out;
755 } else {
756 gl = rhashtable_lookup_fast(&gl_hash_table,
757 name, ht_parms);
758 }
759 if (gl && !lockref_get_not_dead(&gl->gl_lockref)) {
760 rcu_read_unlock();
761 schedule();
762 goto again;
763 }
764 out:
765 rcu_read_unlock();
766 finish_wait(wq, &wait.wait);
767 return gl;
768 }
769
770 /**
771 * gfs2_glock_get() - Get a glock, or create one if one doesn't exist
772 * @sdp: The GFS2 superblock
773 * @number: the lock number
774 * @glops: The glock_operations to use
775 * @create: If 0, don't create the glock if it doesn't exist
776 * @glp: the glock is returned here
777 *
778 * This does not lock a glock, just finds/creates structures for one.
779 *
780 * Returns: errno
781 */
782
783 int gfs2_glock_get(struct gfs2_sbd *sdp, u64 number,
784 const struct gfs2_glock_operations *glops, int create,
785 struct gfs2_glock **glp)
786 {
787 struct super_block *s = sdp->sd_vfs;
788 struct lm_lockname name = { .ln_number = number,
789 .ln_type = glops->go_type,
790 .ln_sbd = sdp };
791 struct gfs2_glock *gl, *tmp;
792 struct address_space *mapping;
793 struct kmem_cache *cachep;
794 int ret = 0;
795
796 gl = find_insert_glock(&name, NULL);
797 if (gl) {
798 *glp = gl;
799 return 0;
800 }
801 if (!create)
802 return -ENOENT;
803
804 if (glops->go_flags & GLOF_ASPACE)
805 cachep = gfs2_glock_aspace_cachep;
806 else
807 cachep = gfs2_glock_cachep;
808 gl = kmem_cache_alloc(cachep, GFP_NOFS);
809 if (!gl)
810 return -ENOMEM;
811
812 memset(&gl->gl_lksb, 0, sizeof(struct dlm_lksb));
813
814 if (glops->go_flags & GLOF_LVB) {
815 gl->gl_lksb.sb_lvbptr = kzalloc(GFS2_MIN_LVB_SIZE, GFP_NOFS);
816 if (!gl->gl_lksb.sb_lvbptr) {
817 kmem_cache_free(cachep, gl);
818 return -ENOMEM;
819 }
820 }
821
822 atomic_inc(&sdp->sd_glock_disposal);
823 gl->gl_node.next = NULL;
824 gl->gl_flags = 0;
825 gl->gl_name = name;
826 gl->gl_lockref.count = 1;
827 gl->gl_state = LM_ST_UNLOCKED;
828 gl->gl_target = LM_ST_UNLOCKED;
829 gl->gl_demote_state = LM_ST_EXCLUSIVE;
830 gl->gl_ops = glops;
831 gl->gl_dstamp = 0;
832 preempt_disable();
833 /* We use the global stats to estimate the initial per-glock stats */
834 gl->gl_stats = this_cpu_ptr(sdp->sd_lkstats)->lkstats[glops->go_type];
835 preempt_enable();
836 gl->gl_stats.stats[GFS2_LKS_DCOUNT] = 0;
837 gl->gl_stats.stats[GFS2_LKS_QCOUNT] = 0;
838 gl->gl_tchange = jiffies;
839 gl->gl_object = NULL;
840 gl->gl_hold_time = GL_GLOCK_DFT_HOLD;
841 INIT_DELAYED_WORK(&gl->gl_work, glock_work_func);
842 INIT_WORK(&gl->gl_delete, delete_work_func);
843
844 mapping = gfs2_glock2aspace(gl);
845 if (mapping) {
846 mapping->a_ops = &gfs2_meta_aops;
847 mapping->host = s->s_bdev->bd_inode;
848 mapping->flags = 0;
849 mapping_set_gfp_mask(mapping, GFP_NOFS);
850 mapping->private_data = NULL;
851 mapping->writeback_index = 0;
852 }
853
854 tmp = find_insert_glock(&name, gl);
855 if (!tmp) {
856 *glp = gl;
857 goto out;
858 }
859 if (IS_ERR(tmp)) {
860 ret = PTR_ERR(tmp);
861 goto out_free;
862 }
863 *glp = tmp;
864
865 out_free:
866 kfree(gl->gl_lksb.sb_lvbptr);
867 kmem_cache_free(cachep, gl);
868 atomic_dec(&sdp->sd_glock_disposal);
869
870 out:
871 return ret;
872 }
873
874 /**
875 * gfs2_holder_init - initialize a struct gfs2_holder in the default way
876 * @gl: the glock
877 * @state: the state we're requesting
878 * @flags: the modifier flags
879 * @gh: the holder structure
880 *
881 */
882
883 void gfs2_holder_init(struct gfs2_glock *gl, unsigned int state, u16 flags,
884 struct gfs2_holder *gh)
885 {
886 INIT_LIST_HEAD(&gh->gh_list);
887 gh->gh_gl = gl;
888 gh->gh_ip = _RET_IP_;
889 gh->gh_owner_pid = get_pid(task_pid(current));
890 gh->gh_state = state;
891 gh->gh_flags = flags;
892 gh->gh_error = 0;
893 gh->gh_iflags = 0;
894 gfs2_glock_hold(gl);
895 }
896
897 /**
898 * gfs2_holder_reinit - reinitialize a struct gfs2_holder so we can requeue it
899 * @state: the state we're requesting
900 * @flags: the modifier flags
901 * @gh: the holder structure
902 *
903 * Don't mess with the glock.
904 *
905 */
906
907 void gfs2_holder_reinit(unsigned int state, u16 flags, struct gfs2_holder *gh)
908 {
909 gh->gh_state = state;
910 gh->gh_flags = flags;
911 gh->gh_iflags = 0;
912 gh->gh_ip = _RET_IP_;
913 put_pid(gh->gh_owner_pid);
914 gh->gh_owner_pid = get_pid(task_pid(current));
915 }
916
917 /**
918 * gfs2_holder_uninit - uninitialize a holder structure (drop glock reference)
919 * @gh: the holder structure
920 *
921 */
922
923 void gfs2_holder_uninit(struct gfs2_holder *gh)
924 {
925 put_pid(gh->gh_owner_pid);
926 gfs2_glock_put(gh->gh_gl);
927 gfs2_holder_mark_uninitialized(gh);
928 gh->gh_ip = 0;
929 }
930
931 /**
932 * gfs2_glock_wait - wait on a glock acquisition
933 * @gh: the glock holder
934 *
935 * Returns: 0 on success
936 */
937
938 int gfs2_glock_wait(struct gfs2_holder *gh)
939 {
940 unsigned long time1 = jiffies;
941
942 might_sleep();
943 wait_on_bit(&gh->gh_iflags, HIF_WAIT, TASK_UNINTERRUPTIBLE);
944 if (time_after(jiffies, time1 + HZ)) /* have we waited > a second? */
945 /* Lengthen the minimum hold time. */
946 gh->gh_gl->gl_hold_time = min(gh->gh_gl->gl_hold_time +
947 GL_GLOCK_HOLD_INCR,
948 GL_GLOCK_MAX_HOLD);
949 return gh->gh_error;
950 }
951
952 /**
953 * handle_callback - process a demote request
954 * @gl: the glock
955 * @state: the state the caller wants us to change to
956 *
957 * There are only two requests that we are going to see in actual
958 * practise: LM_ST_SHARED and LM_ST_UNLOCKED
959 */
960
961 static void handle_callback(struct gfs2_glock *gl, unsigned int state,
962 unsigned long delay, bool remote)
963 {
964 int bit = delay ? GLF_PENDING_DEMOTE : GLF_DEMOTE;
965
966 set_bit(bit, &gl->gl_flags);
967 if (gl->gl_demote_state == LM_ST_EXCLUSIVE) {
968 gl->gl_demote_state = state;
969 gl->gl_demote_time = jiffies;
970 } else if (gl->gl_demote_state != LM_ST_UNLOCKED &&
971 gl->gl_demote_state != state) {
972 gl->gl_demote_state = LM_ST_UNLOCKED;
973 }
974 if (gl->gl_ops->go_callback)
975 gl->gl_ops->go_callback(gl, remote);
976 trace_gfs2_demote_rq(gl, remote);
977 }
978
979 void gfs2_print_dbg(struct seq_file *seq, const char *fmt, ...)
980 {
981 struct va_format vaf;
982 va_list args;
983
984 va_start(args, fmt);
985
986 if (seq) {
987 seq_vprintf(seq, fmt, args);
988 } else {
989 vaf.fmt = fmt;
990 vaf.va = &args;
991
992 pr_err("%pV", &vaf);
993 }
994
995 va_end(args);
996 }
997
998 /**
999 * add_to_queue - Add a holder to the wait queue (but look for recursion)
1000 * @gh: the holder structure to add
1001 *
1002 * Eventually we should move the recursive locking trap to a
1003 * debugging option or something like that. This is the fast
1004 * path and needs to have the minimum number of distractions.
1005 *
1006 */
1007
1008 static inline void add_to_queue(struct gfs2_holder *gh)
1009 __releases(&gl->gl_lockref.lock)
1010 __acquires(&gl->gl_lockref.lock)
1011 {
1012 struct gfs2_glock *gl = gh->gh_gl;
1013 struct gfs2_sbd *sdp = gl->gl_name.ln_sbd;
1014 struct list_head *insert_pt = NULL;
1015 struct gfs2_holder *gh2;
1016 int try_futile = 0;
1017
1018 BUG_ON(gh->gh_owner_pid == NULL);
1019 if (test_and_set_bit(HIF_WAIT, &gh->gh_iflags))
1020 BUG();
1021
1022 if (gh->gh_flags & (LM_FLAG_TRY | LM_FLAG_TRY_1CB)) {
1023 if (test_bit(GLF_LOCK, &gl->gl_flags))
1024 try_futile = !may_grant(gl, gh);
1025 if (test_bit(GLF_INVALIDATE_IN_PROGRESS, &gl->gl_flags))
1026 goto fail;
1027 }
1028
1029 list_for_each_entry(gh2, &gl->gl_holders, gh_list) {
1030 if (unlikely(gh2->gh_owner_pid == gh->gh_owner_pid &&
1031 (gh->gh_gl->gl_ops->go_type != LM_TYPE_FLOCK)))
1032 goto trap_recursive;
1033 if (try_futile &&
1034 !(gh2->gh_flags & (LM_FLAG_TRY | LM_FLAG_TRY_1CB))) {
1035 fail:
1036 gh->gh_error = GLR_TRYFAILED;
1037 gfs2_holder_wake(gh);
1038 return;
1039 }
1040 if (test_bit(HIF_HOLDER, &gh2->gh_iflags))
1041 continue;
1042 if (unlikely((gh->gh_flags & LM_FLAG_PRIORITY) && !insert_pt))
1043 insert_pt = &gh2->gh_list;
1044 }
1045 set_bit(GLF_QUEUED, &gl->gl_flags);
1046 trace_gfs2_glock_queue(gh, 1);
1047 gfs2_glstats_inc(gl, GFS2_LKS_QCOUNT);
1048 gfs2_sbstats_inc(gl, GFS2_LKS_QCOUNT);
1049 if (likely(insert_pt == NULL)) {
1050 list_add_tail(&gh->gh_list, &gl->gl_holders);
1051 if (unlikely(gh->gh_flags & LM_FLAG_PRIORITY))
1052 goto do_cancel;
1053 return;
1054 }
1055 list_add_tail(&gh->gh_list, insert_pt);
1056 do_cancel:
1057 gh = list_entry(gl->gl_holders.next, struct gfs2_holder, gh_list);
1058 if (!(gh->gh_flags & LM_FLAG_PRIORITY)) {
1059 spin_unlock(&gl->gl_lockref.lock);
1060 if (sdp->sd_lockstruct.ls_ops->lm_cancel)
1061 sdp->sd_lockstruct.ls_ops->lm_cancel(gl);
1062 spin_lock(&gl->gl_lockref.lock);
1063 }
1064 return;
1065
1066 trap_recursive:
1067 pr_err("original: %pSR\n", (void *)gh2->gh_ip);
1068 pr_err("pid: %d\n", pid_nr(gh2->gh_owner_pid));
1069 pr_err("lock type: %d req lock state : %d\n",
1070 gh2->gh_gl->gl_name.ln_type, gh2->gh_state);
1071 pr_err("new: %pSR\n", (void *)gh->gh_ip);
1072 pr_err("pid: %d\n", pid_nr(gh->gh_owner_pid));
1073 pr_err("lock type: %d req lock state : %d\n",
1074 gh->gh_gl->gl_name.ln_type, gh->gh_state);
1075 gfs2_dump_glock(NULL, gl);
1076 BUG();
1077 }
1078
1079 /**
1080 * gfs2_glock_nq - enqueue a struct gfs2_holder onto a glock (acquire a glock)
1081 * @gh: the holder structure
1082 *
1083 * if (gh->gh_flags & GL_ASYNC), this never returns an error
1084 *
1085 * Returns: 0, GLR_TRYFAILED, or errno on failure
1086 */
1087
1088 int gfs2_glock_nq(struct gfs2_holder *gh)
1089 {
1090 struct gfs2_glock *gl = gh->gh_gl;
1091 struct gfs2_sbd *sdp = gl->gl_name.ln_sbd;
1092 int error = 0;
1093
1094 if (unlikely(test_bit(SDF_SHUTDOWN, &sdp->sd_flags)))
1095 return -EIO;
1096
1097 if (test_bit(GLF_LRU, &gl->gl_flags))
1098 gfs2_glock_remove_from_lru(gl);
1099
1100 spin_lock(&gl->gl_lockref.lock);
1101 add_to_queue(gh);
1102 if (unlikely((LM_FLAG_NOEXP & gh->gh_flags) &&
1103 test_and_clear_bit(GLF_FROZEN, &gl->gl_flags))) {
1104 set_bit(GLF_REPLY_PENDING, &gl->gl_flags);
1105 gl->gl_lockref.count++;
1106 __gfs2_glock_queue_work(gl, 0);
1107 }
1108 run_queue(gl, 1);
1109 spin_unlock(&gl->gl_lockref.lock);
1110
1111 if (!(gh->gh_flags & GL_ASYNC))
1112 error = gfs2_glock_wait(gh);
1113
1114 return error;
1115 }
1116
1117 /**
1118 * gfs2_glock_poll - poll to see if an async request has been completed
1119 * @gh: the holder
1120 *
1121 * Returns: 1 if the request is ready to be gfs2_glock_wait()ed on
1122 */
1123
1124 int gfs2_glock_poll(struct gfs2_holder *gh)
1125 {
1126 return test_bit(HIF_WAIT, &gh->gh_iflags) ? 0 : 1;
1127 }
1128
1129 /**
1130 * gfs2_glock_dq - dequeue a struct gfs2_holder from a glock (release a glock)
1131 * @gh: the glock holder
1132 *
1133 */
1134
1135 void gfs2_glock_dq(struct gfs2_holder *gh)
1136 {
1137 struct gfs2_glock *gl = gh->gh_gl;
1138 const struct gfs2_glock_operations *glops = gl->gl_ops;
1139 unsigned delay = 0;
1140 int fast_path = 0;
1141
1142 spin_lock(&gl->gl_lockref.lock);
1143 if (gh->gh_flags & GL_NOCACHE)
1144 handle_callback(gl, LM_ST_UNLOCKED, 0, false);
1145
1146 list_del_init(&gh->gh_list);
1147 clear_bit(HIF_HOLDER, &gh->gh_iflags);
1148 if (find_first_holder(gl) == NULL) {
1149 if (glops->go_unlock) {
1150 GLOCK_BUG_ON(gl, test_and_set_bit(GLF_LOCK, &gl->gl_flags));
1151 spin_unlock(&gl->gl_lockref.lock);
1152 glops->go_unlock(gh);
1153 spin_lock(&gl->gl_lockref.lock);
1154 clear_bit(GLF_LOCK, &gl->gl_flags);
1155 }
1156 if (list_empty(&gl->gl_holders) &&
1157 !test_bit(GLF_PENDING_DEMOTE, &gl->gl_flags) &&
1158 !test_bit(GLF_DEMOTE, &gl->gl_flags))
1159 fast_path = 1;
1160 }
1161 if (!test_bit(GLF_LFLUSH, &gl->gl_flags) && demote_ok(gl) &&
1162 (glops->go_flags & GLOF_LRU))
1163 gfs2_glock_add_to_lru(gl);
1164
1165 trace_gfs2_glock_queue(gh, 0);
1166 if (unlikely(!fast_path)) {
1167 gl->gl_lockref.count++;
1168 if (test_bit(GLF_PENDING_DEMOTE, &gl->gl_flags) &&
1169 !test_bit(GLF_DEMOTE, &gl->gl_flags) &&
1170 gl->gl_name.ln_type == LM_TYPE_INODE)
1171 delay = gl->gl_hold_time;
1172 __gfs2_glock_queue_work(gl, delay);
1173 }
1174 spin_unlock(&gl->gl_lockref.lock);
1175 }
1176
1177 void gfs2_glock_dq_wait(struct gfs2_holder *gh)
1178 {
1179 struct gfs2_glock *gl = gh->gh_gl;
1180 gfs2_glock_dq(gh);
1181 might_sleep();
1182 wait_on_bit(&gl->gl_flags, GLF_DEMOTE, TASK_UNINTERRUPTIBLE);
1183 }
1184
1185 /**
1186 * gfs2_glock_dq_uninit - dequeue a holder from a glock and initialize it
1187 * @gh: the holder structure
1188 *
1189 */
1190
1191 void gfs2_glock_dq_uninit(struct gfs2_holder *gh)
1192 {
1193 gfs2_glock_dq(gh);
1194 gfs2_holder_uninit(gh);
1195 }
1196
1197 /**
1198 * gfs2_glock_nq_num - acquire a glock based on lock number
1199 * @sdp: the filesystem
1200 * @number: the lock number
1201 * @glops: the glock operations for the type of glock
1202 * @state: the state to acquire the glock in
1203 * @flags: modifier flags for the acquisition
1204 * @gh: the struct gfs2_holder
1205 *
1206 * Returns: errno
1207 */
1208
1209 int gfs2_glock_nq_num(struct gfs2_sbd *sdp, u64 number,
1210 const struct gfs2_glock_operations *glops,
1211 unsigned int state, u16 flags, struct gfs2_holder *gh)
1212 {
1213 struct gfs2_glock *gl;
1214 int error;
1215
1216 error = gfs2_glock_get(sdp, number, glops, CREATE, &gl);
1217 if (!error) {
1218 error = gfs2_glock_nq_init(gl, state, flags, gh);
1219 gfs2_glock_put(gl);
1220 }
1221
1222 return error;
1223 }
1224
1225 /**
1226 * glock_compare - Compare two struct gfs2_glock structures for sorting
1227 * @arg_a: the first structure
1228 * @arg_b: the second structure
1229 *
1230 */
1231
1232 static int glock_compare(const void *arg_a, const void *arg_b)
1233 {
1234 const struct gfs2_holder *gh_a = *(const struct gfs2_holder **)arg_a;
1235 const struct gfs2_holder *gh_b = *(const struct gfs2_holder **)arg_b;
1236 const struct lm_lockname *a = &gh_a->gh_gl->gl_name;
1237 const struct lm_lockname *b = &gh_b->gh_gl->gl_name;
1238
1239 if (a->ln_number > b->ln_number)
1240 return 1;
1241 if (a->ln_number < b->ln_number)
1242 return -1;
1243 BUG_ON(gh_a->gh_gl->gl_ops->go_type == gh_b->gh_gl->gl_ops->go_type);
1244 return 0;
1245 }
1246
1247 /**
1248 * nq_m_sync - synchonously acquire more than one glock in deadlock free order
1249 * @num_gh: the number of structures
1250 * @ghs: an array of struct gfs2_holder structures
1251 *
1252 * Returns: 0 on success (all glocks acquired),
1253 * errno on failure (no glocks acquired)
1254 */
1255
1256 static int nq_m_sync(unsigned int num_gh, struct gfs2_holder *ghs,
1257 struct gfs2_holder **p)
1258 {
1259 unsigned int x;
1260 int error = 0;
1261
1262 for (x = 0; x < num_gh; x++)
1263 p[x] = &ghs[x];
1264
1265 sort(p, num_gh, sizeof(struct gfs2_holder *), glock_compare, NULL);
1266
1267 for (x = 0; x < num_gh; x++) {
1268 p[x]->gh_flags &= ~(LM_FLAG_TRY | GL_ASYNC);
1269
1270 error = gfs2_glock_nq(p[x]);
1271 if (error) {
1272 while (x--)
1273 gfs2_glock_dq(p[x]);
1274 break;
1275 }
1276 }
1277
1278 return error;
1279 }
1280
1281 /**
1282 * gfs2_glock_nq_m - acquire multiple glocks
1283 * @num_gh: the number of structures
1284 * @ghs: an array of struct gfs2_holder structures
1285 *
1286 *
1287 * Returns: 0 on success (all glocks acquired),
1288 * errno on failure (no glocks acquired)
1289 */
1290
1291 int gfs2_glock_nq_m(unsigned int num_gh, struct gfs2_holder *ghs)
1292 {
1293 struct gfs2_holder *tmp[4];
1294 struct gfs2_holder **pph = tmp;
1295 int error = 0;
1296
1297 switch(num_gh) {
1298 case 0:
1299 return 0;
1300 case 1:
1301 ghs->gh_flags &= ~(LM_FLAG_TRY | GL_ASYNC);
1302 return gfs2_glock_nq(ghs);
1303 default:
1304 if (num_gh <= 4)
1305 break;
1306 pph = kmalloc(num_gh * sizeof(struct gfs2_holder *), GFP_NOFS);
1307 if (!pph)
1308 return -ENOMEM;
1309 }
1310
1311 error = nq_m_sync(num_gh, ghs, pph);
1312
1313 if (pph != tmp)
1314 kfree(pph);
1315
1316 return error;
1317 }
1318
1319 /**
1320 * gfs2_glock_dq_m - release multiple glocks
1321 * @num_gh: the number of structures
1322 * @ghs: an array of struct gfs2_holder structures
1323 *
1324 */
1325
1326 void gfs2_glock_dq_m(unsigned int num_gh, struct gfs2_holder *ghs)
1327 {
1328 while (num_gh--)
1329 gfs2_glock_dq(&ghs[num_gh]);
1330 }
1331
1332 void gfs2_glock_cb(struct gfs2_glock *gl, unsigned int state)
1333 {
1334 unsigned long delay = 0;
1335 unsigned long holdtime;
1336 unsigned long now = jiffies;
1337
1338 gfs2_glock_hold(gl);
1339 holdtime = gl->gl_tchange + gl->gl_hold_time;
1340 if (test_bit(GLF_QUEUED, &gl->gl_flags) &&
1341 gl->gl_name.ln_type == LM_TYPE_INODE) {
1342 if (time_before(now, holdtime))
1343 delay = holdtime - now;
1344 if (test_bit(GLF_REPLY_PENDING, &gl->gl_flags))
1345 delay = gl->gl_hold_time;
1346 }
1347
1348 spin_lock(&gl->gl_lockref.lock);
1349 handle_callback(gl, state, delay, true);
1350 __gfs2_glock_queue_work(gl, delay);
1351 spin_unlock(&gl->gl_lockref.lock);
1352 }
1353
1354 /**
1355 * gfs2_should_freeze - Figure out if glock should be frozen
1356 * @gl: The glock in question
1357 *
1358 * Glocks are not frozen if (a) the result of the dlm operation is
1359 * an error, (b) the locking operation was an unlock operation or
1360 * (c) if there is a "noexp" flagged request anywhere in the queue
1361 *
1362 * Returns: 1 if freezing should occur, 0 otherwise
1363 */
1364
1365 static int gfs2_should_freeze(const struct gfs2_glock *gl)
1366 {
1367 const struct gfs2_holder *gh;
1368
1369 if (gl->gl_reply & ~LM_OUT_ST_MASK)
1370 return 0;
1371 if (gl->gl_target == LM_ST_UNLOCKED)
1372 return 0;
1373
1374 list_for_each_entry(gh, &gl->gl_holders, gh_list) {
1375 if (test_bit(HIF_HOLDER, &gh->gh_iflags))
1376 continue;
1377 if (LM_FLAG_NOEXP & gh->gh_flags)
1378 return 0;
1379 }
1380
1381 return 1;
1382 }
1383
1384 /**
1385 * gfs2_glock_complete - Callback used by locking
1386 * @gl: Pointer to the glock
1387 * @ret: The return value from the dlm
1388 *
1389 * The gl_reply field is under the gl_lockref.lock lock so that it is ok
1390 * to use a bitfield shared with other glock state fields.
1391 */
1392
1393 void gfs2_glock_complete(struct gfs2_glock *gl, int ret)
1394 {
1395 struct lm_lockstruct *ls = &gl->gl_name.ln_sbd->sd_lockstruct;
1396
1397 spin_lock(&gl->gl_lockref.lock);
1398 gl->gl_reply = ret;
1399
1400 if (unlikely(test_bit(DFL_BLOCK_LOCKS, &ls->ls_recover_flags))) {
1401 if (gfs2_should_freeze(gl)) {
1402 set_bit(GLF_FROZEN, &gl->gl_flags);
1403 spin_unlock(&gl->gl_lockref.lock);
1404 return;
1405 }
1406 }
1407
1408 gl->gl_lockref.count++;
1409 set_bit(GLF_REPLY_PENDING, &gl->gl_flags);
1410 __gfs2_glock_queue_work(gl, 0);
1411 spin_unlock(&gl->gl_lockref.lock);
1412 }
1413
1414 static int glock_cmp(void *priv, struct list_head *a, struct list_head *b)
1415 {
1416 struct gfs2_glock *gla, *glb;
1417
1418 gla = list_entry(a, struct gfs2_glock, gl_lru);
1419 glb = list_entry(b, struct gfs2_glock, gl_lru);
1420
1421 if (gla->gl_name.ln_number > glb->gl_name.ln_number)
1422 return 1;
1423 if (gla->gl_name.ln_number < glb->gl_name.ln_number)
1424 return -1;
1425
1426 return 0;
1427 }
1428
1429 /**
1430 * gfs2_dispose_glock_lru - Demote a list of glocks
1431 * @list: The list to dispose of
1432 *
1433 * Disposing of glocks may involve disk accesses, so that here we sort
1434 * the glocks by number (i.e. disk location of the inodes) so that if
1435 * there are any such accesses, they'll be sent in order (mostly).
1436 *
1437 * Must be called under the lru_lock, but may drop and retake this
1438 * lock. While the lru_lock is dropped, entries may vanish from the
1439 * list, but no new entries will appear on the list (since it is
1440 * private)
1441 */
1442
1443 static void gfs2_dispose_glock_lru(struct list_head *list)
1444 __releases(&lru_lock)
1445 __acquires(&lru_lock)
1446 {
1447 struct gfs2_glock *gl;
1448
1449 list_sort(NULL, list, glock_cmp);
1450
1451 while(!list_empty(list)) {
1452 gl = list_entry(list->next, struct gfs2_glock, gl_lru);
1453 list_del_init(&gl->gl_lru);
1454 if (!spin_trylock(&gl->gl_lockref.lock)) {
1455 add_back_to_lru:
1456 list_add(&gl->gl_lru, &lru_list);
1457 atomic_inc(&lru_count);
1458 continue;
1459 }
1460 if (test_and_set_bit(GLF_LOCK, &gl->gl_flags)) {
1461 spin_unlock(&gl->gl_lockref.lock);
1462 goto add_back_to_lru;
1463 }
1464 clear_bit(GLF_LRU, &gl->gl_flags);
1465 gl->gl_lockref.count++;
1466 if (demote_ok(gl))
1467 handle_callback(gl, LM_ST_UNLOCKED, 0, false);
1468 WARN_ON(!test_and_clear_bit(GLF_LOCK, &gl->gl_flags));
1469 __gfs2_glock_queue_work(gl, 0);
1470 spin_unlock(&gl->gl_lockref.lock);
1471 cond_resched_lock(&lru_lock);
1472 }
1473 }
1474
1475 /**
1476 * gfs2_scan_glock_lru - Scan the LRU looking for locks to demote
1477 * @nr: The number of entries to scan
1478 *
1479 * This function selects the entries on the LRU which are able to
1480 * be demoted, and then kicks off the process by calling
1481 * gfs2_dispose_glock_lru() above.
1482 */
1483
1484 static long gfs2_scan_glock_lru(int nr)
1485 {
1486 struct gfs2_glock *gl;
1487 LIST_HEAD(skipped);
1488 LIST_HEAD(dispose);
1489 long freed = 0;
1490
1491 spin_lock(&lru_lock);
1492 while ((nr-- >= 0) && !list_empty(&lru_list)) {
1493 gl = list_entry(lru_list.next, struct gfs2_glock, gl_lru);
1494
1495 /* Test for being demotable */
1496 if (!test_bit(GLF_LOCK, &gl->gl_flags)) {
1497 list_move(&gl->gl_lru, &dispose);
1498 atomic_dec(&lru_count);
1499 freed++;
1500 continue;
1501 }
1502
1503 list_move(&gl->gl_lru, &skipped);
1504 }
1505 list_splice(&skipped, &lru_list);
1506 if (!list_empty(&dispose))
1507 gfs2_dispose_glock_lru(&dispose);
1508 spin_unlock(&lru_lock);
1509
1510 return freed;
1511 }
1512
1513 static unsigned long gfs2_glock_shrink_scan(struct shrinker *shrink,
1514 struct shrink_control *sc)
1515 {
1516 if (!(sc->gfp_mask & __GFP_FS))
1517 return SHRINK_STOP;
1518 return gfs2_scan_glock_lru(sc->nr_to_scan);
1519 }
1520
1521 static unsigned long gfs2_glock_shrink_count(struct shrinker *shrink,
1522 struct shrink_control *sc)
1523 {
1524 return vfs_pressure_ratio(atomic_read(&lru_count));
1525 }
1526
1527 static struct shrinker glock_shrinker = {
1528 .seeks = DEFAULT_SEEKS,
1529 .count_objects = gfs2_glock_shrink_count,
1530 .scan_objects = gfs2_glock_shrink_scan,
1531 };
1532
1533 /**
1534 * examine_bucket - Call a function for glock in a hash bucket
1535 * @examiner: the function
1536 * @sdp: the filesystem
1537 * @bucket: the bucket
1538 *
1539 * Note that the function can be called multiple times on the same
1540 * object. So the user must ensure that the function can cope with
1541 * that.
1542 */
1543
1544 static void glock_hash_walk(glock_examiner examiner, const struct gfs2_sbd *sdp)
1545 {
1546 struct gfs2_glock *gl;
1547 struct rhashtable_iter iter;
1548
1549 rhashtable_walk_enter(&gl_hash_table, &iter);
1550
1551 do {
1552 rhashtable_walk_start(&iter);
1553
1554 while ((gl = rhashtable_walk_next(&iter)) && !IS_ERR(gl))
1555 if (gl->gl_name.ln_sbd == sdp &&
1556 lockref_get_not_dead(&gl->gl_lockref))
1557 examiner(gl);
1558
1559 rhashtable_walk_stop(&iter);
1560 } while (cond_resched(), gl == ERR_PTR(-EAGAIN));
1561
1562 rhashtable_walk_exit(&iter);
1563 }
1564
1565 /**
1566 * thaw_glock - thaw out a glock which has an unprocessed reply waiting
1567 * @gl: The glock to thaw
1568 *
1569 */
1570
1571 static void thaw_glock(struct gfs2_glock *gl)
1572 {
1573 if (!test_and_clear_bit(GLF_FROZEN, &gl->gl_flags)) {
1574 gfs2_glock_put(gl);
1575 return;
1576 }
1577 set_bit(GLF_REPLY_PENDING, &gl->gl_flags);
1578 gfs2_glock_queue_work(gl, 0);
1579 }
1580
1581 /**
1582 * clear_glock - look at a glock and see if we can free it from glock cache
1583 * @gl: the glock to look at
1584 *
1585 */
1586
1587 static void clear_glock(struct gfs2_glock *gl)
1588 {
1589 gfs2_glock_remove_from_lru(gl);
1590
1591 spin_lock(&gl->gl_lockref.lock);
1592 if (gl->gl_state != LM_ST_UNLOCKED)
1593 handle_callback(gl, LM_ST_UNLOCKED, 0, false);
1594 __gfs2_glock_queue_work(gl, 0);
1595 spin_unlock(&gl->gl_lockref.lock);
1596 }
1597
1598 /**
1599 * gfs2_glock_thaw - Thaw any frozen glocks
1600 * @sdp: The super block
1601 *
1602 */
1603
1604 void gfs2_glock_thaw(struct gfs2_sbd *sdp)
1605 {
1606 glock_hash_walk(thaw_glock, sdp);
1607 }
1608
1609 static void dump_glock(struct seq_file *seq, struct gfs2_glock *gl)
1610 {
1611 spin_lock(&gl->gl_lockref.lock);
1612 gfs2_dump_glock(seq, gl);
1613 spin_unlock(&gl->gl_lockref.lock);
1614 }
1615
1616 static void dump_glock_func(struct gfs2_glock *gl)
1617 {
1618 dump_glock(NULL, gl);
1619 }
1620
1621 /**
1622 * gfs2_gl_hash_clear - Empty out the glock hash table
1623 * @sdp: the filesystem
1624 * @wait: wait until it's all gone
1625 *
1626 * Called when unmounting the filesystem.
1627 */
1628
1629 void gfs2_gl_hash_clear(struct gfs2_sbd *sdp)
1630 {
1631 set_bit(SDF_SKIP_DLM_UNLOCK, &sdp->sd_flags);
1632 flush_workqueue(glock_workqueue);
1633 glock_hash_walk(clear_glock, sdp);
1634 flush_workqueue(glock_workqueue);
1635 wait_event_timeout(sdp->sd_glock_wait,
1636 atomic_read(&sdp->sd_glock_disposal) == 0,
1637 HZ * 600);
1638 glock_hash_walk(dump_glock_func, sdp);
1639 }
1640
1641 void gfs2_glock_finish_truncate(struct gfs2_inode *ip)
1642 {
1643 struct gfs2_glock *gl = ip->i_gl;
1644 int ret;
1645
1646 ret = gfs2_truncatei_resume(ip);
1647 gfs2_assert_withdraw(gl->gl_name.ln_sbd, ret == 0);
1648
1649 spin_lock(&gl->gl_lockref.lock);
1650 clear_bit(GLF_LOCK, &gl->gl_flags);
1651 run_queue(gl, 1);
1652 spin_unlock(&gl->gl_lockref.lock);
1653 }
1654
1655 static const char *state2str(unsigned state)
1656 {
1657 switch(state) {
1658 case LM_ST_UNLOCKED:
1659 return "UN";
1660 case LM_ST_SHARED:
1661 return "SH";
1662 case LM_ST_DEFERRED:
1663 return "DF";
1664 case LM_ST_EXCLUSIVE:
1665 return "EX";
1666 }
1667 return "??";
1668 }
1669
1670 static const char *hflags2str(char *buf, u16 flags, unsigned long iflags)
1671 {
1672 char *p = buf;
1673 if (flags & LM_FLAG_TRY)
1674 *p++ = 't';
1675 if (flags & LM_FLAG_TRY_1CB)
1676 *p++ = 'T';
1677 if (flags & LM_FLAG_NOEXP)
1678 *p++ = 'e';
1679 if (flags & LM_FLAG_ANY)
1680 *p++ = 'A';
1681 if (flags & LM_FLAG_PRIORITY)
1682 *p++ = 'p';
1683 if (flags & GL_ASYNC)
1684 *p++ = 'a';
1685 if (flags & GL_EXACT)
1686 *p++ = 'E';
1687 if (flags & GL_NOCACHE)
1688 *p++ = 'c';
1689 if (test_bit(HIF_HOLDER, &iflags))
1690 *p++ = 'H';
1691 if (test_bit(HIF_WAIT, &iflags))
1692 *p++ = 'W';
1693 if (test_bit(HIF_FIRST, &iflags))
1694 *p++ = 'F';
1695 *p = 0;
1696 return buf;
1697 }
1698
1699 /**
1700 * dump_holder - print information about a glock holder
1701 * @seq: the seq_file struct
1702 * @gh: the glock holder
1703 *
1704 */
1705
1706 static void dump_holder(struct seq_file *seq, const struct gfs2_holder *gh)
1707 {
1708 struct task_struct *gh_owner = NULL;
1709 char flags_buf[32];
1710
1711 rcu_read_lock();
1712 if (gh->gh_owner_pid)
1713 gh_owner = pid_task(gh->gh_owner_pid, PIDTYPE_PID);
1714 gfs2_print_dbg(seq, " H: s:%s f:%s e:%d p:%ld [%s] %pS\n",
1715 state2str(gh->gh_state),
1716 hflags2str(flags_buf, gh->gh_flags, gh->gh_iflags),
1717 gh->gh_error,
1718 gh->gh_owner_pid ? (long)pid_nr(gh->gh_owner_pid) : -1,
1719 gh_owner ? gh_owner->comm : "(ended)",
1720 (void *)gh->gh_ip);
1721 rcu_read_unlock();
1722 }
1723
1724 static const char *gflags2str(char *buf, const struct gfs2_glock *gl)
1725 {
1726 const unsigned long *gflags = &gl->gl_flags;
1727 char *p = buf;
1728
1729 if (test_bit(GLF_LOCK, gflags))
1730 *p++ = 'l';
1731 if (test_bit(GLF_DEMOTE, gflags))
1732 *p++ = 'D';
1733 if (test_bit(GLF_PENDING_DEMOTE, gflags))
1734 *p++ = 'd';
1735 if (test_bit(GLF_DEMOTE_IN_PROGRESS, gflags))
1736 *p++ = 'p';
1737 if (test_bit(GLF_DIRTY, gflags))
1738 *p++ = 'y';
1739 if (test_bit(GLF_LFLUSH, gflags))
1740 *p++ = 'f';
1741 if (test_bit(GLF_INVALIDATE_IN_PROGRESS, gflags))
1742 *p++ = 'i';
1743 if (test_bit(GLF_REPLY_PENDING, gflags))
1744 *p++ = 'r';
1745 if (test_bit(GLF_INITIAL, gflags))
1746 *p++ = 'I';
1747 if (test_bit(GLF_FROZEN, gflags))
1748 *p++ = 'F';
1749 if (test_bit(GLF_QUEUED, gflags))
1750 *p++ = 'q';
1751 if (test_bit(GLF_LRU, gflags))
1752 *p++ = 'L';
1753 if (gl->gl_object)
1754 *p++ = 'o';
1755 if (test_bit(GLF_BLOCKING, gflags))
1756 *p++ = 'b';
1757 *p = 0;
1758 return buf;
1759 }
1760
1761 /**
1762 * gfs2_dump_glock - print information about a glock
1763 * @seq: The seq_file struct
1764 * @gl: the glock
1765 *
1766 * The file format is as follows:
1767 * One line per object, capital letters are used to indicate objects
1768 * G = glock, I = Inode, R = rgrp, H = holder. Glocks are not indented,
1769 * other objects are indented by a single space and follow the glock to
1770 * which they are related. Fields are indicated by lower case letters
1771 * followed by a colon and the field value, except for strings which are in
1772 * [] so that its possible to see if they are composed of spaces for
1773 * example. The field's are n = number (id of the object), f = flags,
1774 * t = type, s = state, r = refcount, e = error, p = pid.
1775 *
1776 */
1777
1778 void gfs2_dump_glock(struct seq_file *seq, const struct gfs2_glock *gl)
1779 {
1780 const struct gfs2_glock_operations *glops = gl->gl_ops;
1781 unsigned long long dtime;
1782 const struct gfs2_holder *gh;
1783 char gflags_buf[32];
1784
1785 dtime = jiffies - gl->gl_demote_time;
1786 dtime *= 1000000/HZ; /* demote time in uSec */
1787 if (!test_bit(GLF_DEMOTE, &gl->gl_flags))
1788 dtime = 0;
1789 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",
1790 state2str(gl->gl_state),
1791 gl->gl_name.ln_type,
1792 (unsigned long long)gl->gl_name.ln_number,
1793 gflags2str(gflags_buf, gl),
1794 state2str(gl->gl_target),
1795 state2str(gl->gl_demote_state), dtime,
1796 atomic_read(&gl->gl_ail_count),
1797 atomic_read(&gl->gl_revokes),
1798 (int)gl->gl_lockref.count, gl->gl_hold_time);
1799
1800 list_for_each_entry(gh, &gl->gl_holders, gh_list)
1801 dump_holder(seq, gh);
1802
1803 if (gl->gl_state != LM_ST_UNLOCKED && glops->go_dump)
1804 glops->go_dump(seq, gl);
1805 }
1806
1807 static int gfs2_glstats_seq_show(struct seq_file *seq, void *iter_ptr)
1808 {
1809 struct gfs2_glock *gl = iter_ptr;
1810
1811 seq_printf(seq, "G: n:%u/%llx rtt:%llu/%llu rttb:%llu/%llu irt:%llu/%llu dcnt: %llu qcnt: %llu\n",
1812 gl->gl_name.ln_type,
1813 (unsigned long long)gl->gl_name.ln_number,
1814 (unsigned long long)gl->gl_stats.stats[GFS2_LKS_SRTT],
1815 (unsigned long long)gl->gl_stats.stats[GFS2_LKS_SRTTVAR],
1816 (unsigned long long)gl->gl_stats.stats[GFS2_LKS_SRTTB],
1817 (unsigned long long)gl->gl_stats.stats[GFS2_LKS_SRTTVARB],
1818 (unsigned long long)gl->gl_stats.stats[GFS2_LKS_SIRT],
1819 (unsigned long long)gl->gl_stats.stats[GFS2_LKS_SIRTVAR],
1820 (unsigned long long)gl->gl_stats.stats[GFS2_LKS_DCOUNT],
1821 (unsigned long long)gl->gl_stats.stats[GFS2_LKS_QCOUNT]);
1822 return 0;
1823 }
1824
1825 static const char *gfs2_gltype[] = {
1826 "type",
1827 "reserved",
1828 "nondisk",
1829 "inode",
1830 "rgrp",
1831 "meta",
1832 "iopen",
1833 "flock",
1834 "plock",
1835 "quota",
1836 "journal",
1837 };
1838
1839 static const char *gfs2_stype[] = {
1840 [GFS2_LKS_SRTT] = "srtt",
1841 [GFS2_LKS_SRTTVAR] = "srttvar",
1842 [GFS2_LKS_SRTTB] = "srttb",
1843 [GFS2_LKS_SRTTVARB] = "srttvarb",
1844 [GFS2_LKS_SIRT] = "sirt",
1845 [GFS2_LKS_SIRTVAR] = "sirtvar",
1846 [GFS2_LKS_DCOUNT] = "dlm",
1847 [GFS2_LKS_QCOUNT] = "queue",
1848 };
1849
1850 #define GFS2_NR_SBSTATS (ARRAY_SIZE(gfs2_gltype) * ARRAY_SIZE(gfs2_stype))
1851
1852 static int gfs2_sbstats_seq_show(struct seq_file *seq, void *iter_ptr)
1853 {
1854 struct gfs2_sbd *sdp = seq->private;
1855 loff_t pos = *(loff_t *)iter_ptr;
1856 unsigned index = pos >> 3;
1857 unsigned subindex = pos & 0x07;
1858 int i;
1859
1860 if (index == 0 && subindex != 0)
1861 return 0;
1862
1863 seq_printf(seq, "%-10s %8s:", gfs2_gltype[index],
1864 (index == 0) ? "cpu": gfs2_stype[subindex]);
1865
1866 for_each_possible_cpu(i) {
1867 const struct gfs2_pcpu_lkstats *lkstats = per_cpu_ptr(sdp->sd_lkstats, i);
1868
1869 if (index == 0)
1870 seq_printf(seq, " %15u", i);
1871 else
1872 seq_printf(seq, " %15llu", (unsigned long long)lkstats->
1873 lkstats[index - 1].stats[subindex]);
1874 }
1875 seq_putc(seq, '\n');
1876 return 0;
1877 }
1878
1879 int __init gfs2_glock_init(void)
1880 {
1881 int i, ret;
1882
1883 ret = rhashtable_init(&gl_hash_table, &ht_parms);
1884 if (ret < 0)
1885 return ret;
1886
1887 glock_workqueue = alloc_workqueue("glock_workqueue", WQ_MEM_RECLAIM |
1888 WQ_HIGHPRI | WQ_FREEZABLE, 0);
1889 if (!glock_workqueue) {
1890 rhashtable_destroy(&gl_hash_table);
1891 return -ENOMEM;
1892 }
1893 gfs2_delete_workqueue = alloc_workqueue("delete_workqueue",
1894 WQ_MEM_RECLAIM | WQ_FREEZABLE,
1895 0);
1896 if (!gfs2_delete_workqueue) {
1897 destroy_workqueue(glock_workqueue);
1898 rhashtable_destroy(&gl_hash_table);
1899 return -ENOMEM;
1900 }
1901
1902 ret = register_shrinker(&glock_shrinker);
1903 if (ret) {
1904 destroy_workqueue(gfs2_delete_workqueue);
1905 destroy_workqueue(glock_workqueue);
1906 rhashtable_destroy(&gl_hash_table);
1907 return ret;
1908 }
1909
1910 for (i = 0; i < GLOCK_WAIT_TABLE_SIZE; i++)
1911 init_waitqueue_head(glock_wait_table + i);
1912
1913 return 0;
1914 }
1915
1916 void gfs2_glock_exit(void)
1917 {
1918 unregister_shrinker(&glock_shrinker);
1919 rhashtable_destroy(&gl_hash_table);
1920 destroy_workqueue(glock_workqueue);
1921 destroy_workqueue(gfs2_delete_workqueue);
1922 }
1923
1924 static void gfs2_glock_iter_next(struct gfs2_glock_iter *gi, loff_t n)
1925 {
1926 if (n == 0)
1927 gi->gl = rhashtable_walk_peek(&gi->hti);
1928 else {
1929 gi->gl = rhashtable_walk_next(&gi->hti);
1930 n--;
1931 }
1932 for (;;) {
1933 if (IS_ERR_OR_NULL(gi->gl)) {
1934 if (!gi->gl)
1935 return;
1936 if (PTR_ERR(gi->gl) != -EAGAIN) {
1937 gi->gl = NULL;
1938 return;
1939 }
1940 n = 0;
1941 } else if (gi->sdp == gi->gl->gl_name.ln_sbd &&
1942 !__lockref_is_dead(&gi->gl->gl_lockref)) {
1943 if (!n--)
1944 break;
1945 }
1946 gi->gl = rhashtable_walk_next(&gi->hti);
1947 }
1948 }
1949
1950 static void *gfs2_glock_seq_start(struct seq_file *seq, loff_t *pos)
1951 __acquires(RCU)
1952 {
1953 struct gfs2_glock_iter *gi = seq->private;
1954 loff_t n;
1955
1956 /*
1957 * We can either stay where we are, skip to the next hash table
1958 * entry, or start from the beginning.
1959 */
1960 if (*pos < gi->last_pos) {
1961 rhashtable_walk_exit(&gi->hti);
1962 rhashtable_walk_enter(&gl_hash_table, &gi->hti);
1963 n = *pos + 1;
1964 } else {
1965 n = *pos - gi->last_pos;
1966 }
1967
1968 rhashtable_walk_start(&gi->hti);
1969
1970 gfs2_glock_iter_next(gi, n);
1971 gi->last_pos = *pos;
1972 return gi->gl;
1973 }
1974
1975 static void *gfs2_glock_seq_next(struct seq_file *seq, void *iter_ptr,
1976 loff_t *pos)
1977 {
1978 struct gfs2_glock_iter *gi = seq->private;
1979
1980 (*pos)++;
1981 gi->last_pos = *pos;
1982 gfs2_glock_iter_next(gi, 1);
1983 return gi->gl;
1984 }
1985
1986 static void gfs2_glock_seq_stop(struct seq_file *seq, void *iter_ptr)
1987 __releases(RCU)
1988 {
1989 struct gfs2_glock_iter *gi = seq->private;
1990
1991 gi->gl = NULL;
1992 rhashtable_walk_stop(&gi->hti);
1993 }
1994
1995 static int gfs2_glock_seq_show(struct seq_file *seq, void *iter_ptr)
1996 {
1997 dump_glock(seq, iter_ptr);
1998 return 0;
1999 }
2000
2001 static void *gfs2_sbstats_seq_start(struct seq_file *seq, loff_t *pos)
2002 {
2003 preempt_disable();
2004 if (*pos >= GFS2_NR_SBSTATS)
2005 return NULL;
2006 return pos;
2007 }
2008
2009 static void *gfs2_sbstats_seq_next(struct seq_file *seq, void *iter_ptr,
2010 loff_t *pos)
2011 {
2012 (*pos)++;
2013 if (*pos >= GFS2_NR_SBSTATS)
2014 return NULL;
2015 return pos;
2016 }
2017
2018 static void gfs2_sbstats_seq_stop(struct seq_file *seq, void *iter_ptr)
2019 {
2020 preempt_enable();
2021 }
2022
2023 static const struct seq_operations gfs2_glock_seq_ops = {
2024 .start = gfs2_glock_seq_start,
2025 .next = gfs2_glock_seq_next,
2026 .stop = gfs2_glock_seq_stop,
2027 .show = gfs2_glock_seq_show,
2028 };
2029
2030 static const struct seq_operations gfs2_glstats_seq_ops = {
2031 .start = gfs2_glock_seq_start,
2032 .next = gfs2_glock_seq_next,
2033 .stop = gfs2_glock_seq_stop,
2034 .show = gfs2_glstats_seq_show,
2035 };
2036
2037 static const struct seq_operations gfs2_sbstats_seq_ops = {
2038 .start = gfs2_sbstats_seq_start,
2039 .next = gfs2_sbstats_seq_next,
2040 .stop = gfs2_sbstats_seq_stop,
2041 .show = gfs2_sbstats_seq_show,
2042 };
2043
2044 #define GFS2_SEQ_GOODSIZE min(PAGE_SIZE << PAGE_ALLOC_COSTLY_ORDER, 65536UL)
2045
2046 static int __gfs2_glocks_open(struct inode *inode, struct file *file,
2047 const struct seq_operations *ops)
2048 {
2049 int ret = seq_open_private(file, ops, sizeof(struct gfs2_glock_iter));
2050 if (ret == 0) {
2051 struct seq_file *seq = file->private_data;
2052 struct gfs2_glock_iter *gi = seq->private;
2053
2054 gi->sdp = inode->i_private;
2055 seq->buf = kmalloc(GFS2_SEQ_GOODSIZE, GFP_KERNEL | __GFP_NOWARN);
2056 if (seq->buf)
2057 seq->size = GFS2_SEQ_GOODSIZE;
2058 /*
2059 * Initially, we are "before" the first hash table entry; the
2060 * first call to rhashtable_walk_next gets us the first entry.
2061 */
2062 gi->last_pos = -1;
2063 gi->gl = NULL;
2064 rhashtable_walk_enter(&gl_hash_table, &gi->hti);
2065 }
2066 return ret;
2067 }
2068
2069 static int gfs2_glocks_open(struct inode *inode, struct file *file)
2070 {
2071 return __gfs2_glocks_open(inode, file, &gfs2_glock_seq_ops);
2072 }
2073
2074 static int gfs2_glocks_release(struct inode *inode, struct file *file)
2075 {
2076 struct seq_file *seq = file->private_data;
2077 struct gfs2_glock_iter *gi = seq->private;
2078
2079 gi->gl = NULL;
2080 rhashtable_walk_exit(&gi->hti);
2081 return seq_release_private(inode, file);
2082 }
2083
2084 static int gfs2_glstats_open(struct inode *inode, struct file *file)
2085 {
2086 return __gfs2_glocks_open(inode, file, &gfs2_glstats_seq_ops);
2087 }
2088
2089 static int gfs2_sbstats_open(struct inode *inode, struct file *file)
2090 {
2091 int ret = seq_open(file, &gfs2_sbstats_seq_ops);
2092 if (ret == 0) {
2093 struct seq_file *seq = file->private_data;
2094 seq->private = inode->i_private; /* sdp */
2095 }
2096 return ret;
2097 }
2098
2099 static const struct file_operations gfs2_glocks_fops = {
2100 .owner = THIS_MODULE,
2101 .open = gfs2_glocks_open,
2102 .read = seq_read,
2103 .llseek = seq_lseek,
2104 .release = gfs2_glocks_release,
2105 };
2106
2107 static const struct file_operations gfs2_glstats_fops = {
2108 .owner = THIS_MODULE,
2109 .open = gfs2_glstats_open,
2110 .read = seq_read,
2111 .llseek = seq_lseek,
2112 .release = gfs2_glocks_release,
2113 };
2114
2115 static const struct file_operations gfs2_sbstats_fops = {
2116 .owner = THIS_MODULE,
2117 .open = gfs2_sbstats_open,
2118 .read = seq_read,
2119 .llseek = seq_lseek,
2120 .release = seq_release,
2121 };
2122
2123 int gfs2_create_debugfs_file(struct gfs2_sbd *sdp)
2124 {
2125 struct dentry *dent;
2126
2127 dent = debugfs_create_dir(sdp->sd_table_name, gfs2_root);
2128 if (IS_ERR_OR_NULL(dent))
2129 goto fail;
2130 sdp->debugfs_dir = dent;
2131
2132 dent = debugfs_create_file("glocks",
2133 S_IFREG | S_IRUGO,
2134 sdp->debugfs_dir, sdp,
2135 &gfs2_glocks_fops);
2136 if (IS_ERR_OR_NULL(dent))
2137 goto fail;
2138 sdp->debugfs_dentry_glocks = dent;
2139
2140 dent = debugfs_create_file("glstats",
2141 S_IFREG | S_IRUGO,
2142 sdp->debugfs_dir, sdp,
2143 &gfs2_glstats_fops);
2144 if (IS_ERR_OR_NULL(dent))
2145 goto fail;
2146 sdp->debugfs_dentry_glstats = dent;
2147
2148 dent = debugfs_create_file("sbstats",
2149 S_IFREG | S_IRUGO,
2150 sdp->debugfs_dir, sdp,
2151 &gfs2_sbstats_fops);
2152 if (IS_ERR_OR_NULL(dent))
2153 goto fail;
2154 sdp->debugfs_dentry_sbstats = dent;
2155
2156 return 0;
2157 fail:
2158 gfs2_delete_debugfs_file(sdp);
2159 return dent ? PTR_ERR(dent) : -ENOMEM;
2160 }
2161
2162 void gfs2_delete_debugfs_file(struct gfs2_sbd *sdp)
2163 {
2164 if (sdp->debugfs_dir) {
2165 if (sdp->debugfs_dentry_glocks) {
2166 debugfs_remove(sdp->debugfs_dentry_glocks);
2167 sdp->debugfs_dentry_glocks = NULL;
2168 }
2169 if (sdp->debugfs_dentry_glstats) {
2170 debugfs_remove(sdp->debugfs_dentry_glstats);
2171 sdp->debugfs_dentry_glstats = NULL;
2172 }
2173 if (sdp->debugfs_dentry_sbstats) {
2174 debugfs_remove(sdp->debugfs_dentry_sbstats);
2175 sdp->debugfs_dentry_sbstats = NULL;
2176 }
2177 debugfs_remove(sdp->debugfs_dir);
2178 sdp->debugfs_dir = NULL;
2179 }
2180 }
2181
2182 int gfs2_register_debugfs(void)
2183 {
2184 gfs2_root = debugfs_create_dir("gfs2", NULL);
2185 if (IS_ERR(gfs2_root))
2186 return PTR_ERR(gfs2_root);
2187 return gfs2_root ? 0 : -ENOMEM;
2188 }
2189
2190 void gfs2_unregister_debugfs(void)
2191 {
2192 debugfs_remove(gfs2_root);
2193 gfs2_root = NULL;
2194 }
Linux with added FPC-III support