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f81232: switch to ->get_serial()
[linux/fpc-iii.git] / fs / gfs2 / glock.c
blob4614ee25f6211efe24550edfdd68021ceaa20bf7
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_array(num_gh, sizeof(struct gfs2_holder *),
1307 GFP_NOFS);
1308 if (!pph)
1309 return -ENOMEM;
1310 }
1311
1312 error = nq_m_sync(num_gh, ghs, pph);
1313
1314 if (pph != tmp)
1315 kfree(pph);
1316
1317 return error;
1318 }
1319
1320 /**
1321 * gfs2_glock_dq_m - release multiple glocks
1322 * @num_gh: the number of structures
1323 * @ghs: an array of struct gfs2_holder structures
1324 *
1325 */
1326
1327 void gfs2_glock_dq_m(unsigned int num_gh, struct gfs2_holder *ghs)
1328 {
1329 while (num_gh--)
1330 gfs2_glock_dq(&ghs[num_gh]);
1331 }
1332
1333 void gfs2_glock_cb(struct gfs2_glock *gl, unsigned int state)
1334 {
1335 unsigned long delay = 0;
1336 unsigned long holdtime;
1337 unsigned long now = jiffies;
1338
1339 gfs2_glock_hold(gl);
1340 holdtime = gl->gl_tchange + gl->gl_hold_time;
1341 if (test_bit(GLF_QUEUED, &gl->gl_flags) &&
1342 gl->gl_name.ln_type == LM_TYPE_INODE) {
1343 if (time_before(now, holdtime))
1344 delay = holdtime - now;
1345 if (test_bit(GLF_REPLY_PENDING, &gl->gl_flags))
1346 delay = gl->gl_hold_time;
1347 }
1348
1349 spin_lock(&gl->gl_lockref.lock);
1350 handle_callback(gl, state, delay, true);
1351 __gfs2_glock_queue_work(gl, delay);
1352 spin_unlock(&gl->gl_lockref.lock);
1353 }
1354
1355 /**
1356 * gfs2_should_freeze - Figure out if glock should be frozen
1357 * @gl: The glock in question
1358 *
1359 * Glocks are not frozen if (a) the result of the dlm operation is
1360 * an error, (b) the locking operation was an unlock operation or
1361 * (c) if there is a "noexp" flagged request anywhere in the queue
1362 *
1363 * Returns: 1 if freezing should occur, 0 otherwise
1364 */
1365
1366 static int gfs2_should_freeze(const struct gfs2_glock *gl)
1367 {
1368 const struct gfs2_holder *gh;
1369
1370 if (gl->gl_reply & ~LM_OUT_ST_MASK)
1371 return 0;
1372 if (gl->gl_target == LM_ST_UNLOCKED)
1373 return 0;
1374
1375 list_for_each_entry(gh, &gl->gl_holders, gh_list) {
1376 if (test_bit(HIF_HOLDER, &gh->gh_iflags))
1377 continue;
1378 if (LM_FLAG_NOEXP & gh->gh_flags)
1379 return 0;
1380 }
1381
1382 return 1;
1383 }
1384
1385 /**
1386 * gfs2_glock_complete - Callback used by locking
1387 * @gl: Pointer to the glock
1388 * @ret: The return value from the dlm
1389 *
1390 * The gl_reply field is under the gl_lockref.lock lock so that it is ok
1391 * to use a bitfield shared with other glock state fields.
1392 */
1393
1394 void gfs2_glock_complete(struct gfs2_glock *gl, int ret)
1395 {
1396 struct lm_lockstruct *ls = &gl->gl_name.ln_sbd->sd_lockstruct;
1397
1398 spin_lock(&gl->gl_lockref.lock);
1399 gl->gl_reply = ret;
1400
1401 if (unlikely(test_bit(DFL_BLOCK_LOCKS, &ls->ls_recover_flags))) {
1402 if (gfs2_should_freeze(gl)) {
1403 set_bit(GLF_FROZEN, &gl->gl_flags);
1404 spin_unlock(&gl->gl_lockref.lock);
1405 return;
1406 }
1407 }
1408
1409 gl->gl_lockref.count++;
1410 set_bit(GLF_REPLY_PENDING, &gl->gl_flags);
1411 __gfs2_glock_queue_work(gl, 0);
1412 spin_unlock(&gl->gl_lockref.lock);
1413 }
1414
1415 static int glock_cmp(void *priv, struct list_head *a, struct list_head *b)
1416 {
1417 struct gfs2_glock *gla, *glb;
1418
1419 gla = list_entry(a, struct gfs2_glock, gl_lru);
1420 glb = list_entry(b, struct gfs2_glock, gl_lru);
1421
1422 if (gla->gl_name.ln_number > glb->gl_name.ln_number)
1423 return 1;
1424 if (gla->gl_name.ln_number < glb->gl_name.ln_number)
1425 return -1;
1426
1427 return 0;
1428 }
1429
1430 /**
1431 * gfs2_dispose_glock_lru - Demote a list of glocks
1432 * @list: The list to dispose of
1433 *
1434 * Disposing of glocks may involve disk accesses, so that here we sort
1435 * the glocks by number (i.e. disk location of the inodes) so that if
1436 * there are any such accesses, they'll be sent in order (mostly).
1437 *
1438 * Must be called under the lru_lock, but may drop and retake this
1439 * lock. While the lru_lock is dropped, entries may vanish from the
1440 * list, but no new entries will appear on the list (since it is
1441 * private)
1442 */
1443
1444 static void gfs2_dispose_glock_lru(struct list_head *list)
1445 __releases(&lru_lock)
1446 __acquires(&lru_lock)
1447 {
1448 struct gfs2_glock *gl;
1449
1450 list_sort(NULL, list, glock_cmp);
1451
1452 while(!list_empty(list)) {
1453 gl = list_entry(list->next, struct gfs2_glock, gl_lru);
1454 list_del_init(&gl->gl_lru);
1455 if (!spin_trylock(&gl->gl_lockref.lock)) {
1456 add_back_to_lru:
1457 list_add(&gl->gl_lru, &lru_list);
1458 atomic_inc(&lru_count);
1459 continue;
1460 }
1461 if (test_and_set_bit(GLF_LOCK, &gl->gl_flags)) {
1462 spin_unlock(&gl->gl_lockref.lock);
1463 goto add_back_to_lru;
1464 }
1465 clear_bit(GLF_LRU, &gl->gl_flags);
1466 gl->gl_lockref.count++;
1467 if (demote_ok(gl))
1468 handle_callback(gl, LM_ST_UNLOCKED, 0, false);
1469 WARN_ON(!test_and_clear_bit(GLF_LOCK, &gl->gl_flags));
1470 __gfs2_glock_queue_work(gl, 0);
1471 spin_unlock(&gl->gl_lockref.lock);
1472 cond_resched_lock(&lru_lock);
1473 }
1474 }
1475
1476 /**
1477 * gfs2_scan_glock_lru - Scan the LRU looking for locks to demote
1478 * @nr: The number of entries to scan
1479 *
1480 * This function selects the entries on the LRU which are able to
1481 * be demoted, and then kicks off the process by calling
1482 * gfs2_dispose_glock_lru() above.
1483 */
1484
1485 static long gfs2_scan_glock_lru(int nr)
1486 {
1487 struct gfs2_glock *gl;
1488 LIST_HEAD(skipped);
1489 LIST_HEAD(dispose);
1490 long freed = 0;
1491
1492 spin_lock(&lru_lock);
1493 while ((nr-- >= 0) && !list_empty(&lru_list)) {
1494 gl = list_entry(lru_list.next, struct gfs2_glock, gl_lru);
1495
1496 /* Test for being demotable */
1497 if (!test_bit(GLF_LOCK, &gl->gl_flags)) {
1498 list_move(&gl->gl_lru, &dispose);
1499 atomic_dec(&lru_count);
1500 freed++;
1501 continue;
1502 }
1503
1504 list_move(&gl->gl_lru, &skipped);
1505 }
1506 list_splice(&skipped, &lru_list);
1507 if (!list_empty(&dispose))
1508 gfs2_dispose_glock_lru(&dispose);
1509 spin_unlock(&lru_lock);
1510
1511 return freed;
1512 }
1513
1514 static unsigned long gfs2_glock_shrink_scan(struct shrinker *shrink,
1515 struct shrink_control *sc)
1516 {
1517 if (!(sc->gfp_mask & __GFP_FS))
1518 return SHRINK_STOP;
1519 return gfs2_scan_glock_lru(sc->nr_to_scan);
1520 }
1521
1522 static unsigned long gfs2_glock_shrink_count(struct shrinker *shrink,
1523 struct shrink_control *sc)
1524 {
1525 return vfs_pressure_ratio(atomic_read(&lru_count));
1526 }
1527
1528 static struct shrinker glock_shrinker = {
1529 .seeks = DEFAULT_SEEKS,
1530 .count_objects = gfs2_glock_shrink_count,
1531 .scan_objects = gfs2_glock_shrink_scan,
1532 };
1533
1534 /**
1535 * examine_bucket - Call a function for glock in a hash bucket
1536 * @examiner: the function
1537 * @sdp: the filesystem
1538 * @bucket: the bucket
1539 *
1540 * Note that the function can be called multiple times on the same
1541 * object. So the user must ensure that the function can cope with
1542 * that.
1543 */
1544
1545 static void glock_hash_walk(glock_examiner examiner, const struct gfs2_sbd *sdp)
1546 {
1547 struct gfs2_glock *gl;
1548 struct rhashtable_iter iter;
1549
1550 rhashtable_walk_enter(&gl_hash_table, &iter);
1551
1552 do {
1553 rhashtable_walk_start(&iter);
1554
1555 while ((gl = rhashtable_walk_next(&iter)) && !IS_ERR(gl))
1556 if (gl->gl_name.ln_sbd == sdp &&
1557 lockref_get_not_dead(&gl->gl_lockref))
1558 examiner(gl);
1559
1560 rhashtable_walk_stop(&iter);
1561 } while (cond_resched(), gl == ERR_PTR(-EAGAIN));
1562
1563 rhashtable_walk_exit(&iter);
1564 }
1565
1566 /**
1567 * thaw_glock - thaw out a glock which has an unprocessed reply waiting
1568 * @gl: The glock to thaw
1569 *
1570 */
1571
1572 static void thaw_glock(struct gfs2_glock *gl)
1573 {
1574 if (!test_and_clear_bit(GLF_FROZEN, &gl->gl_flags)) {
1575 gfs2_glock_put(gl);
1576 return;
1577 }
1578 set_bit(GLF_REPLY_PENDING, &gl->gl_flags);
1579 gfs2_glock_queue_work(gl, 0);
1580 }
1581
1582 /**
1583 * clear_glock - look at a glock and see if we can free it from glock cache
1584 * @gl: the glock to look at
1585 *
1586 */
1587
1588 static void clear_glock(struct gfs2_glock *gl)
1589 {
1590 gfs2_glock_remove_from_lru(gl);
1591
1592 spin_lock(&gl->gl_lockref.lock);
1593 if (gl->gl_state != LM_ST_UNLOCKED)
1594 handle_callback(gl, LM_ST_UNLOCKED, 0, false);
1595 __gfs2_glock_queue_work(gl, 0);
1596 spin_unlock(&gl->gl_lockref.lock);
1597 }
1598
1599 /**
1600 * gfs2_glock_thaw - Thaw any frozen glocks
1601 * @sdp: The super block
1602 *
1603 */
1604
1605 void gfs2_glock_thaw(struct gfs2_sbd *sdp)
1606 {
1607 glock_hash_walk(thaw_glock, sdp);
1608 }
1609
1610 static void dump_glock(struct seq_file *seq, struct gfs2_glock *gl)
1611 {
1612 spin_lock(&gl->gl_lockref.lock);
1613 gfs2_dump_glock(seq, gl);
1614 spin_unlock(&gl->gl_lockref.lock);
1615 }
1616
1617 static void dump_glock_func(struct gfs2_glock *gl)
1618 {
1619 dump_glock(NULL, gl);
1620 }
1621
1622 /**
1623 * gfs2_gl_hash_clear - Empty out the glock hash table
1624 * @sdp: the filesystem
1625 * @wait: wait until it's all gone
1626 *
1627 * Called when unmounting the filesystem.
1628 */
1629
1630 void gfs2_gl_hash_clear(struct gfs2_sbd *sdp)
1631 {
1632 set_bit(SDF_SKIP_DLM_UNLOCK, &sdp->sd_flags);
1633 flush_workqueue(glock_workqueue);
1634 glock_hash_walk(clear_glock, sdp);
1635 flush_workqueue(glock_workqueue);
1636 wait_event_timeout(sdp->sd_glock_wait,
1637 atomic_read(&sdp->sd_glock_disposal) == 0,
1638 HZ * 600);
1639 glock_hash_walk(dump_glock_func, sdp);
1640 }
1641
1642 void gfs2_glock_finish_truncate(struct gfs2_inode *ip)
1643 {
1644 struct gfs2_glock *gl = ip->i_gl;
1645 int ret;
1646
1647 ret = gfs2_truncatei_resume(ip);
1648 gfs2_assert_withdraw(gl->gl_name.ln_sbd, ret == 0);
1649
1650 spin_lock(&gl->gl_lockref.lock);
1651 clear_bit(GLF_LOCK, &gl->gl_flags);
1652 run_queue(gl, 1);
1653 spin_unlock(&gl->gl_lockref.lock);
1654 }
1655
1656 static const char *state2str(unsigned state)
1657 {
1658 switch(state) {
1659 case LM_ST_UNLOCKED:
1660 return "UN";
1661 case LM_ST_SHARED:
1662 return "SH";
1663 case LM_ST_DEFERRED:
1664 return "DF";
1665 case LM_ST_EXCLUSIVE:
1666 return "EX";
1667 }
1668 return "??";
1669 }
1670
1671 static const char *hflags2str(char *buf, u16 flags, unsigned long iflags)
1672 {
1673 char *p = buf;
1674 if (flags & LM_FLAG_TRY)
1675 *p++ = 't';
1676 if (flags & LM_FLAG_TRY_1CB)
1677 *p++ = 'T';
1678 if (flags & LM_FLAG_NOEXP)
1679 *p++ = 'e';
1680 if (flags & LM_FLAG_ANY)
1681 *p++ = 'A';
1682 if (flags & LM_FLAG_PRIORITY)
1683 *p++ = 'p';
1684 if (flags & GL_ASYNC)
1685 *p++ = 'a';
1686 if (flags & GL_EXACT)
1687 *p++ = 'E';
1688 if (flags & GL_NOCACHE)
1689 *p++ = 'c';
1690 if (test_bit(HIF_HOLDER, &iflags))
1691 *p++ = 'H';
1692 if (test_bit(HIF_WAIT, &iflags))
1693 *p++ = 'W';
1694 if (test_bit(HIF_FIRST, &iflags))
1695 *p++ = 'F';
1696 *p = 0;
1697 return buf;
1698 }
1699
1700 /**
1701 * dump_holder - print information about a glock holder
1702 * @seq: the seq_file struct
1703 * @gh: the glock holder
1704 *
1705 */
1706
1707 static void dump_holder(struct seq_file *seq, const struct gfs2_holder *gh)
1708 {
1709 struct task_struct *gh_owner = NULL;
1710 char flags_buf[32];
1711
1712 rcu_read_lock();
1713 if (gh->gh_owner_pid)
1714 gh_owner = pid_task(gh->gh_owner_pid, PIDTYPE_PID);
1715 gfs2_print_dbg(seq, " H: s:%s f:%s e:%d p:%ld [%s] %pS\n",
1716 state2str(gh->gh_state),
1717 hflags2str(flags_buf, gh->gh_flags, gh->gh_iflags),
1718 gh->gh_error,
1719 gh->gh_owner_pid ? (long)pid_nr(gh->gh_owner_pid) : -1,
1720 gh_owner ? gh_owner->comm : "(ended)",
1721 (void *)gh->gh_ip);
1722 rcu_read_unlock();
1723 }
1724
1725 static const char *gflags2str(char *buf, const struct gfs2_glock *gl)
1726 {
1727 const unsigned long *gflags = &gl->gl_flags;
1728 char *p = buf;
1729
1730 if (test_bit(GLF_LOCK, gflags))
1731 *p++ = 'l';
1732 if (test_bit(GLF_DEMOTE, gflags))
1733 *p++ = 'D';
1734 if (test_bit(GLF_PENDING_DEMOTE, gflags))
1735 *p++ = 'd';
1736 if (test_bit(GLF_DEMOTE_IN_PROGRESS, gflags))
1737 *p++ = 'p';
1738 if (test_bit(GLF_DIRTY, gflags))
1739 *p++ = 'y';
1740 if (test_bit(GLF_LFLUSH, gflags))
1741 *p++ = 'f';
1742 if (test_bit(GLF_INVALIDATE_IN_PROGRESS, gflags))
1743 *p++ = 'i';
1744 if (test_bit(GLF_REPLY_PENDING, gflags))
1745 *p++ = 'r';
1746 if (test_bit(GLF_INITIAL, gflags))
1747 *p++ = 'I';
1748 if (test_bit(GLF_FROZEN, gflags))
1749 *p++ = 'F';
1750 if (test_bit(GLF_QUEUED, gflags))
1751 *p++ = 'q';
1752 if (test_bit(GLF_LRU, gflags))
1753 *p++ = 'L';
1754 if (gl->gl_object)
1755 *p++ = 'o';
1756 if (test_bit(GLF_BLOCKING, gflags))
1757 *p++ = 'b';
1758 *p = 0;
1759 return buf;
1760 }
1761
1762 /**
1763 * gfs2_dump_glock - print information about a glock
1764 * @seq: The seq_file struct
1765 * @gl: the glock
1766 *
1767 * The file format is as follows:
1768 * One line per object, capital letters are used to indicate objects
1769 * G = glock, I = Inode, R = rgrp, H = holder. Glocks are not indented,
1770 * other objects are indented by a single space and follow the glock to
1771 * which they are related. Fields are indicated by lower case letters
1772 * followed by a colon and the field value, except for strings which are in
1773 * [] so that its possible to see if they are composed of spaces for
1774 * example. The field's are n = number (id of the object), f = flags,
1775 * t = type, s = state, r = refcount, e = error, p = pid.
1776 *
1777 */
1778
1779 void gfs2_dump_glock(struct seq_file *seq, const struct gfs2_glock *gl)
1780 {
1781 const struct gfs2_glock_operations *glops = gl->gl_ops;
1782 unsigned long long dtime;
1783 const struct gfs2_holder *gh;
1784 char gflags_buf[32];
1785
1786 dtime = jiffies - gl->gl_demote_time;
1787 dtime *= 1000000/HZ; /* demote time in uSec */
1788 if (!test_bit(GLF_DEMOTE, &gl->gl_flags))
1789 dtime = 0;
1790 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",
1791 state2str(gl->gl_state),
1792 gl->gl_name.ln_type,
1793 (unsigned long long)gl->gl_name.ln_number,
1794 gflags2str(gflags_buf, gl),
1795 state2str(gl->gl_target),
1796 state2str(gl->gl_demote_state), dtime,
1797 atomic_read(&gl->gl_ail_count),
1798 atomic_read(&gl->gl_revokes),
1799 (int)gl->gl_lockref.count, gl->gl_hold_time);
1800
1801 list_for_each_entry(gh, &gl->gl_holders, gh_list)
1802 dump_holder(seq, gh);
1803
1804 if (gl->gl_state != LM_ST_UNLOCKED && glops->go_dump)
1805 glops->go_dump(seq, gl);
1806 }
1807
1808 static int gfs2_glstats_seq_show(struct seq_file *seq, void *iter_ptr)
1809 {
1810 struct gfs2_glock *gl = iter_ptr;
1811
1812 seq_printf(seq, "G: n:%u/%llx rtt:%llu/%llu rttb:%llu/%llu irt:%llu/%llu dcnt: %llu qcnt: %llu\n",
1813 gl->gl_name.ln_type,
1814 (unsigned long long)gl->gl_name.ln_number,
1815 (unsigned long long)gl->gl_stats.stats[GFS2_LKS_SRTT],
1816 (unsigned long long)gl->gl_stats.stats[GFS2_LKS_SRTTVAR],
1817 (unsigned long long)gl->gl_stats.stats[GFS2_LKS_SRTTB],
1818 (unsigned long long)gl->gl_stats.stats[GFS2_LKS_SRTTVARB],
1819 (unsigned long long)gl->gl_stats.stats[GFS2_LKS_SIRT],
1820 (unsigned long long)gl->gl_stats.stats[GFS2_LKS_SIRTVAR],
1821 (unsigned long long)gl->gl_stats.stats[GFS2_LKS_DCOUNT],
1822 (unsigned long long)gl->gl_stats.stats[GFS2_LKS_QCOUNT]);
1823 return 0;
1824 }
1825
1826 static const char *gfs2_gltype[] = {
1827 "type",
1828 "reserved",
1829 "nondisk",
1830 "inode",
1831 "rgrp",
1832 "meta",
1833 "iopen",
1834 "flock",
1835 "plock",
1836 "quota",
1837 "journal",
1838 };
1839
1840 static const char *gfs2_stype[] = {
1841 [GFS2_LKS_SRTT] = "srtt",
1842 [GFS2_LKS_SRTTVAR] = "srttvar",
1843 [GFS2_LKS_SRTTB] = "srttb",
1844 [GFS2_LKS_SRTTVARB] = "srttvarb",
1845 [GFS2_LKS_SIRT] = "sirt",
1846 [GFS2_LKS_SIRTVAR] = "sirtvar",
1847 [GFS2_LKS_DCOUNT] = "dlm",
1848 [GFS2_LKS_QCOUNT] = "queue",
1849 };
1850
1851 #define GFS2_NR_SBSTATS (ARRAY_SIZE(gfs2_gltype) * ARRAY_SIZE(gfs2_stype))
1852
1853 static int gfs2_sbstats_seq_show(struct seq_file *seq, void *iter_ptr)
1854 {
1855 struct gfs2_sbd *sdp = seq->private;
1856 loff_t pos = *(loff_t *)iter_ptr;
1857 unsigned index = pos >> 3;
1858 unsigned subindex = pos & 0x07;
1859 int i;
1860
1861 if (index == 0 && subindex != 0)
1862 return 0;
1863
1864 seq_printf(seq, "%-10s %8s:", gfs2_gltype[index],
1865 (index == 0) ? "cpu": gfs2_stype[subindex]);
1866
1867 for_each_possible_cpu(i) {
1868 const struct gfs2_pcpu_lkstats *lkstats = per_cpu_ptr(sdp->sd_lkstats, i);
1869
1870 if (index == 0)
1871 seq_printf(seq, " %15u", i);
1872 else
1873 seq_printf(seq, " %15llu", (unsigned long long)lkstats->
1874 lkstats[index - 1].stats[subindex]);
1875 }
1876 seq_putc(seq, '\n');
1877 return 0;
1878 }
1879
1880 int __init gfs2_glock_init(void)
1881 {
1882 int i, ret;
1883
1884 ret = rhashtable_init(&gl_hash_table, &ht_parms);
1885 if (ret < 0)
1886 return ret;
1887
1888 glock_workqueue = alloc_workqueue("glock_workqueue", WQ_MEM_RECLAIM |
1889 WQ_HIGHPRI | WQ_FREEZABLE, 0);
1890 if (!glock_workqueue) {
1891 rhashtable_destroy(&gl_hash_table);
1892 return -ENOMEM;
1893 }
1894 gfs2_delete_workqueue = alloc_workqueue("delete_workqueue",
1895 WQ_MEM_RECLAIM | WQ_FREEZABLE,
1896 0);
1897 if (!gfs2_delete_workqueue) {
1898 destroy_workqueue(glock_workqueue);
1899 rhashtable_destroy(&gl_hash_table);
1900 return -ENOMEM;
1901 }
1902
1903 ret = register_shrinker(&glock_shrinker);
1904 if (ret) {
1905 destroy_workqueue(gfs2_delete_workqueue);
1906 destroy_workqueue(glock_workqueue);
1907 rhashtable_destroy(&gl_hash_table);
1908 return ret;
1909 }
1910
1911 for (i = 0; i < GLOCK_WAIT_TABLE_SIZE; i++)
1912 init_waitqueue_head(glock_wait_table + i);
1913
1914 return 0;
1915 }
1916
1917 void gfs2_glock_exit(void)
1918 {
1919 unregister_shrinker(&glock_shrinker);
1920 rhashtable_destroy(&gl_hash_table);
1921 destroy_workqueue(glock_workqueue);
1922 destroy_workqueue(gfs2_delete_workqueue);
1923 }
1924
1925 static void gfs2_glock_iter_next(struct gfs2_glock_iter *gi, loff_t n)
1926 {
1927 struct gfs2_glock *gl = gi->gl;
1928
1929 if (gl) {
1930 if (n == 0)
1931 return;
1932 if (!lockref_put_not_zero(&gl->gl_lockref))
1933 gfs2_glock_queue_put(gl);
1934 }
1935 for (;;) {
1936 gl = rhashtable_walk_next(&gi->hti);
1937 if (IS_ERR_OR_NULL(gl)) {
1938 if (gl == ERR_PTR(-EAGAIN)) {
1939 n = 1;
1940 continue;
1941 }
1942 gl = NULL;
1943 break;
1944 }
1945 if (gl->gl_name.ln_sbd != gi->sdp)
1946 continue;
1947 if (n <= 1) {
1948 if (!lockref_get_not_dead(&gl->gl_lockref))
1949 continue;
1950 break;
1951 } else {
1952 if (__lockref_is_dead(&gl->gl_lockref))
1953 continue;
1954 n--;
1955 }
1956 }
1957 gi->gl = gl;
1958 }
1959
1960 static void *gfs2_glock_seq_start(struct seq_file *seq, loff_t *pos)
1961 __acquires(RCU)
1962 {
1963 struct gfs2_glock_iter *gi = seq->private;
1964 loff_t n;
1965
1966 /*
1967 * We can either stay where we are, skip to the next hash table
1968 * entry, or start from the beginning.
1969 */
1970 if (*pos < gi->last_pos) {
1971 rhashtable_walk_exit(&gi->hti);
1972 rhashtable_walk_enter(&gl_hash_table, &gi->hti);
1973 n = *pos + 1;
1974 } else {
1975 n = *pos - gi->last_pos;
1976 }
1977
1978 rhashtable_walk_start(&gi->hti);
1979
1980 gfs2_glock_iter_next(gi, n);
1981 gi->last_pos = *pos;
1982 return gi->gl;
1983 }
1984
1985 static void *gfs2_glock_seq_next(struct seq_file *seq, void *iter_ptr,
1986 loff_t *pos)
1987 {
1988 struct gfs2_glock_iter *gi = seq->private;
1989
1990 (*pos)++;
1991 gi->last_pos = *pos;
1992 gfs2_glock_iter_next(gi, 1);
1993 return gi->gl;
1994 }
1995
1996 static void gfs2_glock_seq_stop(struct seq_file *seq, void *iter_ptr)
1997 __releases(RCU)
1998 {
1999 struct gfs2_glock_iter *gi = seq->private;
2000
2001 rhashtable_walk_stop(&gi->hti);
2002 }
2003
2004 static int gfs2_glock_seq_show(struct seq_file *seq, void *iter_ptr)
2005 {
2006 dump_glock(seq, iter_ptr);
2007 return 0;
2008 }
2009
2010 static void *gfs2_sbstats_seq_start(struct seq_file *seq, loff_t *pos)
2011 {
2012 preempt_disable();
2013 if (*pos >= GFS2_NR_SBSTATS)
2014 return NULL;
2015 return pos;
2016 }
2017
2018 static void *gfs2_sbstats_seq_next(struct seq_file *seq, void *iter_ptr,
2019 loff_t *pos)
2020 {
2021 (*pos)++;
2022 if (*pos >= GFS2_NR_SBSTATS)
2023 return NULL;
2024 return pos;
2025 }
2026
2027 static void gfs2_sbstats_seq_stop(struct seq_file *seq, void *iter_ptr)
2028 {
2029 preempt_enable();
2030 }
2031
2032 static const struct seq_operations gfs2_glock_seq_ops = {
2033 .start = gfs2_glock_seq_start,
2034 .next = gfs2_glock_seq_next,
2035 .stop = gfs2_glock_seq_stop,
2036 .show = gfs2_glock_seq_show,
2037 };
2038
2039 static const struct seq_operations gfs2_glstats_seq_ops = {
2040 .start = gfs2_glock_seq_start,
2041 .next = gfs2_glock_seq_next,
2042 .stop = gfs2_glock_seq_stop,
2043 .show = gfs2_glstats_seq_show,
2044 };
2045
2046 static const struct seq_operations gfs2_sbstats_seq_ops = {
2047 .start = gfs2_sbstats_seq_start,
2048 .next = gfs2_sbstats_seq_next,
2049 .stop = gfs2_sbstats_seq_stop,
2050 .show = gfs2_sbstats_seq_show,
2051 };
2052
2053 #define GFS2_SEQ_GOODSIZE min(PAGE_SIZE << PAGE_ALLOC_COSTLY_ORDER, 65536UL)
2054
2055 static int __gfs2_glocks_open(struct inode *inode, struct file *file,
2056 const struct seq_operations *ops)
2057 {
2058 int ret = seq_open_private(file, ops, sizeof(struct gfs2_glock_iter));
2059 if (ret == 0) {
2060 struct seq_file *seq = file->private_data;
2061 struct gfs2_glock_iter *gi = seq->private;
2062
2063 gi->sdp = inode->i_private;
2064 seq->buf = kmalloc(GFS2_SEQ_GOODSIZE, GFP_KERNEL | __GFP_NOWARN);
2065 if (seq->buf)
2066 seq->size = GFS2_SEQ_GOODSIZE;
2067 /*
2068 * Initially, we are "before" the first hash table entry; the
2069 * first call to rhashtable_walk_next gets us the first entry.
2070 */
2071 gi->last_pos = -1;
2072 gi->gl = NULL;
2073 rhashtable_walk_enter(&gl_hash_table, &gi->hti);
2074 }
2075 return ret;
2076 }
2077
2078 static int gfs2_glocks_open(struct inode *inode, struct file *file)
2079 {
2080 return __gfs2_glocks_open(inode, file, &gfs2_glock_seq_ops);
2081 }
2082
2083 static int gfs2_glocks_release(struct inode *inode, struct file *file)
2084 {
2085 struct seq_file *seq = file->private_data;
2086 struct gfs2_glock_iter *gi = seq->private;
2087
2088 if (gi->gl)
2089 gfs2_glock_put(gi->gl);
2090 rhashtable_walk_exit(&gi->hti);
2091 return seq_release_private(inode, file);
2092 }
2093
2094 static int gfs2_glstats_open(struct inode *inode, struct file *file)
2095 {
2096 return __gfs2_glocks_open(inode, file, &gfs2_glstats_seq_ops);
2097 }
2098
2099 static int gfs2_sbstats_open(struct inode *inode, struct file *file)
2100 {
2101 int ret = seq_open(file, &gfs2_sbstats_seq_ops);
2102 if (ret == 0) {
2103 struct seq_file *seq = file->private_data;
2104 seq->private = inode->i_private; /* sdp */
2105 }
2106 return ret;
2107 }
2108
2109 static const struct file_operations gfs2_glocks_fops = {
2110 .owner = THIS_MODULE,
2111 .open = gfs2_glocks_open,
2112 .read = seq_read,
2113 .llseek = seq_lseek,
2114 .release = gfs2_glocks_release,
2115 };
2116
2117 static const struct file_operations gfs2_glstats_fops = {
2118 .owner = THIS_MODULE,
2119 .open = gfs2_glstats_open,
2120 .read = seq_read,
2121 .llseek = seq_lseek,
2122 .release = gfs2_glocks_release,
2123 };
2124
2125 static const struct file_operations gfs2_sbstats_fops = {
2126 .owner = THIS_MODULE,
2127 .open = gfs2_sbstats_open,
2128 .read = seq_read,
2129 .llseek = seq_lseek,
2130 .release = seq_release,
2131 };
2132
2133 int gfs2_create_debugfs_file(struct gfs2_sbd *sdp)
2134 {
2135 struct dentry *dent;
2136
2137 dent = debugfs_create_dir(sdp->sd_table_name, gfs2_root);
2138 if (IS_ERR_OR_NULL(dent))
2139 goto fail;
2140 sdp->debugfs_dir = dent;
2141
2142 dent = debugfs_create_file("glocks",
2143 S_IFREG | S_IRUGO,
2144 sdp->debugfs_dir, sdp,
2145 &gfs2_glocks_fops);
2146 if (IS_ERR_OR_NULL(dent))
2147 goto fail;
2148 sdp->debugfs_dentry_glocks = dent;
2149
2150 dent = debugfs_create_file("glstats",
2151 S_IFREG | S_IRUGO,
2152 sdp->debugfs_dir, sdp,
2153 &gfs2_glstats_fops);
2154 if (IS_ERR_OR_NULL(dent))
2155 goto fail;
2156 sdp->debugfs_dentry_glstats = dent;
2157
2158 dent = debugfs_create_file("sbstats",
2159 S_IFREG | S_IRUGO,
2160 sdp->debugfs_dir, sdp,
2161 &gfs2_sbstats_fops);
2162 if (IS_ERR_OR_NULL(dent))
2163 goto fail;
2164 sdp->debugfs_dentry_sbstats = dent;
2165
2166 return 0;
2167 fail:
2168 gfs2_delete_debugfs_file(sdp);
2169 return dent ? PTR_ERR(dent) : -ENOMEM;
2170 }
2171
2172 void gfs2_delete_debugfs_file(struct gfs2_sbd *sdp)
2173 {
2174 if (sdp->debugfs_dir) {
2175 if (sdp->debugfs_dentry_glocks) {
2176 debugfs_remove(sdp->debugfs_dentry_glocks);
2177 sdp->debugfs_dentry_glocks = NULL;
2178 }
2179 if (sdp->debugfs_dentry_glstats) {
2180 debugfs_remove(sdp->debugfs_dentry_glstats);
2181 sdp->debugfs_dentry_glstats = NULL;
2182 }
2183 if (sdp->debugfs_dentry_sbstats) {
2184 debugfs_remove(sdp->debugfs_dentry_sbstats);
2185 sdp->debugfs_dentry_sbstats = NULL;
2186 }
2187 debugfs_remove(sdp->debugfs_dir);
2188 sdp->debugfs_dir = NULL;
2189 }
2190 }
2191
2192 int gfs2_register_debugfs(void)
2193 {
2194 gfs2_root = debugfs_create_dir("gfs2", NULL);
2195 if (IS_ERR(gfs2_root))
2196 return PTR_ERR(gfs2_root);
2197 return gfs2_root ? 0 : -ENOMEM;
2198 }
2199
2200 void gfs2_unregister_debugfs(void)
2201 {
2202 debugfs_remove(gfs2_root);
2203 gfs2_root = NULL;
2204 }
Linux with added FPC-III support