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ARM: shmobile: Add DT bindings for Renesas memory controllers
[linux/fpc-iii.git] / fs / gfs2 / glock.c
bloba23524aa3eac34a33902e0a9bd1304936d7017fc
1 /*
2 * Copyright (C) Sistina Software, Inc. 1997-2003 All rights reserved.
3 * Copyright (C) 2004-2008 Red Hat, Inc. All rights reserved.
4 *
5 * This copyrighted material is made available to anyone wishing to use,
6 * modify, copy, or redistribute it subject to the terms and conditions
7 * of the GNU General Public License version 2.
8 */
9
10 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
11
12 #include <linux/sched.h>
13 #include <linux/slab.h>
14 #include <linux/spinlock.h>
15 #include <linux/buffer_head.h>
16 #include <linux/delay.h>
17 #include <linux/sort.h>
18 #include <linux/jhash.h>
19 #include <linux/kallsyms.h>
20 #include <linux/gfs2_ondisk.h>
21 #include <linux/list.h>
22 #include <linux/wait.h>
23 #include <linux/module.h>
24 #include <asm/uaccess.h>
25 #include <linux/seq_file.h>
26 #include <linux/debugfs.h>
27 #include <linux/kthread.h>
28 #include <linux/freezer.h>
29 #include <linux/workqueue.h>
30 #include <linux/jiffies.h>
31 #include <linux/rcupdate.h>
32 #include <linux/rculist_bl.h>
33 #include <linux/bit_spinlock.h>
34 #include <linux/percpu.h>
35 #include <linux/list_sort.h>
36 #include <linux/lockref.h>
37
38 #include "gfs2.h"
39 #include "incore.h"
40 #include "glock.h"
41 #include "glops.h"
42 #include "inode.h"
43 #include "lops.h"
44 #include "meta_io.h"
45 #include "quota.h"
46 #include "super.h"
47 #include "util.h"
48 #include "bmap.h"
49 #define CREATE_TRACE_POINTS
50 #include "trace_gfs2.h"
51
52 struct gfs2_glock_iter {
53 int hash; /* hash bucket index */
54 unsigned nhash; /* Index within current bucket */
55 struct gfs2_sbd *sdp; /* incore superblock */
56 struct gfs2_glock *gl; /* current glock struct */
57 loff_t last_pos; /* last position */
58 };
59
60 typedef void (*glock_examiner) (struct gfs2_glock * gl);
61
62 static void do_xmote(struct gfs2_glock *gl, struct gfs2_holder *gh, unsigned int target);
63
64 static struct dentry *gfs2_root;
65 static struct workqueue_struct *glock_workqueue;
66 struct workqueue_struct *gfs2_delete_workqueue;
67 static LIST_HEAD(lru_list);
68 static atomic_t lru_count = ATOMIC_INIT(0);
69 static DEFINE_SPINLOCK(lru_lock);
70
71 #define GFS2_GL_HASH_SHIFT 15
72 #define GFS2_GL_HASH_SIZE (1 << GFS2_GL_HASH_SHIFT)
73 #define GFS2_GL_HASH_MASK (GFS2_GL_HASH_SIZE - 1)
74
75 static struct hlist_bl_head gl_hash_table[GFS2_GL_HASH_SIZE];
76 static struct dentry *gfs2_root;
77
78 /**
79 * gl_hash() - Turn glock number into hash bucket number
80 * @lock: The glock number
81 *
82 * Returns: The number of the corresponding hash bucket
83 */
84
85 static unsigned int gl_hash(const struct gfs2_sbd *sdp,
86 const struct lm_lockname *name)
87 {
88 unsigned int h;
89
90 h = jhash(&name->ln_number, sizeof(u64), 0);
91 h = jhash(&name->ln_type, sizeof(unsigned int), h);
92 h = jhash(&sdp, sizeof(struct gfs2_sbd *), h);
93 h &= GFS2_GL_HASH_MASK;
94
95 return h;
96 }
97
98 static inline void spin_lock_bucket(unsigned int hash)
99 {
100 hlist_bl_lock(&gl_hash_table[hash]);
101 }
102
103 static inline void spin_unlock_bucket(unsigned int hash)
104 {
105 hlist_bl_unlock(&gl_hash_table[hash]);
106 }
107
108 static void gfs2_glock_dealloc(struct rcu_head *rcu)
109 {
110 struct gfs2_glock *gl = container_of(rcu, struct gfs2_glock, gl_rcu);
111
112 if (gl->gl_ops->go_flags & GLOF_ASPACE) {
113 kmem_cache_free(gfs2_glock_aspace_cachep, gl);
114 } else {
115 kfree(gl->gl_lksb.sb_lvbptr);
116 kmem_cache_free(gfs2_glock_cachep, gl);
117 }
118 }
119
120 void gfs2_glock_free(struct gfs2_glock *gl)
121 {
122 struct gfs2_sbd *sdp = gl->gl_sbd;
123
124 call_rcu(&gl->gl_rcu, gfs2_glock_dealloc);
125 if (atomic_dec_and_test(&sdp->sd_glock_disposal))
126 wake_up(&sdp->sd_glock_wait);
127 }
128
129 /**
130 * gfs2_glock_hold() - increment reference count on glock
131 * @gl: The glock to hold
132 *
133 */
134
135 static void gfs2_glock_hold(struct gfs2_glock *gl)
136 {
137 GLOCK_BUG_ON(gl, __lockref_is_dead(&gl->gl_lockref));
138 lockref_get(&gl->gl_lockref);
139 }
140
141 /**
142 * demote_ok - Check to see if it's ok to unlock a glock
143 * @gl: the glock
144 *
145 * Returns: 1 if it's ok
146 */
147
148 static int demote_ok(const struct gfs2_glock *gl)
149 {
150 const struct gfs2_glock_operations *glops = gl->gl_ops;
151
152 if (gl->gl_state == LM_ST_UNLOCKED)
153 return 0;
154 if (!list_empty(&gl->gl_holders))
155 return 0;
156 if (glops->go_demote_ok)
157 return glops->go_demote_ok(gl);
158 return 1;
159 }
160
161
162 void gfs2_glock_add_to_lru(struct gfs2_glock *gl)
163 {
164 spin_lock(&lru_lock);
165
166 if (!list_empty(&gl->gl_lru))
167 list_del_init(&gl->gl_lru);
168 else
169 atomic_inc(&lru_count);
170
171 list_add_tail(&gl->gl_lru, &lru_list);
172 set_bit(GLF_LRU, &gl->gl_flags);
173 spin_unlock(&lru_lock);
174 }
175
176 static void __gfs2_glock_remove_from_lru(struct gfs2_glock *gl)
177 {
178 if (!list_empty(&gl->gl_lru)) {
179 list_del_init(&gl->gl_lru);
180 atomic_dec(&lru_count);
181 clear_bit(GLF_LRU, &gl->gl_flags);
182 }
183 }
184
185 static void gfs2_glock_remove_from_lru(struct gfs2_glock *gl)
186 {
187 spin_lock(&lru_lock);
188 __gfs2_glock_remove_from_lru(gl);
189 spin_unlock(&lru_lock);
190 }
191
192 /**
193 * gfs2_glock_put() - Decrement reference count on glock
194 * @gl: The glock to put
195 *
196 */
197
198 void gfs2_glock_put(struct gfs2_glock *gl)
199 {
200 struct gfs2_sbd *sdp = gl->gl_sbd;
201 struct address_space *mapping = gfs2_glock2aspace(gl);
202
203 if (lockref_put_or_lock(&gl->gl_lockref))
204 return;
205
206 lockref_mark_dead(&gl->gl_lockref);
207
208 spin_lock(&lru_lock);
209 __gfs2_glock_remove_from_lru(gl);
210 spin_unlock(&lru_lock);
211 spin_unlock(&gl->gl_lockref.lock);
212 spin_lock_bucket(gl->gl_hash);
213 hlist_bl_del_rcu(&gl->gl_list);
214 spin_unlock_bucket(gl->gl_hash);
215 GLOCK_BUG_ON(gl, !list_empty(&gl->gl_holders));
216 GLOCK_BUG_ON(gl, mapping && mapping->nrpages);
217 trace_gfs2_glock_put(gl);
218 sdp->sd_lockstruct.ls_ops->lm_put_lock(gl);
219 }
220
221 /**
222 * search_bucket() - Find struct gfs2_glock by lock number
223 * @bucket: the bucket to search
224 * @name: The lock name
225 *
226 * Returns: NULL, or the struct gfs2_glock with the requested number
227 */
228
229 static struct gfs2_glock *search_bucket(unsigned int hash,
230 const struct gfs2_sbd *sdp,
231 const struct lm_lockname *name)
232 {
233 struct gfs2_glock *gl;
234 struct hlist_bl_node *h;
235
236 hlist_bl_for_each_entry_rcu(gl, h, &gl_hash_table[hash], gl_list) {
237 if (!lm_name_equal(&gl->gl_name, name))
238 continue;
239 if (gl->gl_sbd != sdp)
240 continue;
241 if (lockref_get_not_dead(&gl->gl_lockref))
242 return gl;
243 }
244
245 return NULL;
246 }
247
248 /**
249 * may_grant - check if its ok to grant a new lock
250 * @gl: The glock
251 * @gh: The lock request which we wish to grant
252 *
253 * Returns: true if its ok to grant the lock
254 */
255
256 static inline int may_grant(const struct gfs2_glock *gl, const struct gfs2_holder *gh)
257 {
258 const struct gfs2_holder *gh_head = list_entry(gl->gl_holders.next, const struct gfs2_holder, gh_list);
259 if ((gh->gh_state == LM_ST_EXCLUSIVE ||
260 gh_head->gh_state == LM_ST_EXCLUSIVE) && gh != gh_head)
261 return 0;
262 if (gl->gl_state == gh->gh_state)
263 return 1;
264 if (gh->gh_flags & GL_EXACT)
265 return 0;
266 if (gl->gl_state == LM_ST_EXCLUSIVE) {
267 if (gh->gh_state == LM_ST_SHARED && gh_head->gh_state == LM_ST_SHARED)
268 return 1;
269 if (gh->gh_state == LM_ST_DEFERRED && gh_head->gh_state == LM_ST_DEFERRED)
270 return 1;
271 }
272 if (gl->gl_state != LM_ST_UNLOCKED && (gh->gh_flags & LM_FLAG_ANY))
273 return 1;
274 return 0;
275 }
276
277 static void gfs2_holder_wake(struct gfs2_holder *gh)
278 {
279 clear_bit(HIF_WAIT, &gh->gh_iflags);
280 smp_mb__after_atomic();
281 wake_up_bit(&gh->gh_iflags, HIF_WAIT);
282 }
283
284 /**
285 * do_error - Something unexpected has happened during a lock request
286 *
287 */
288
289 static inline void do_error(struct gfs2_glock *gl, const int ret)
290 {
291 struct gfs2_holder *gh, *tmp;
292
293 list_for_each_entry_safe(gh, tmp, &gl->gl_holders, gh_list) {
294 if (test_bit(HIF_HOLDER, &gh->gh_iflags))
295 continue;
296 if (ret & LM_OUT_ERROR)
297 gh->gh_error = -EIO;
298 else if (gh->gh_flags & (LM_FLAG_TRY | LM_FLAG_TRY_1CB))
299 gh->gh_error = GLR_TRYFAILED;
300 else
301 continue;
302 list_del_init(&gh->gh_list);
303 trace_gfs2_glock_queue(gh, 0);
304 gfs2_holder_wake(gh);
305 }
306 }
307
308 /**
309 * do_promote - promote as many requests as possible on the current queue
310 * @gl: The glock
311 *
312 * Returns: 1 if there is a blocked holder at the head of the list, or 2
313 * if a type specific operation is underway.
314 */
315
316 static int do_promote(struct gfs2_glock *gl)
317 __releases(&gl->gl_spin)
318 __acquires(&gl->gl_spin)
319 {
320 const struct gfs2_glock_operations *glops = gl->gl_ops;
321 struct gfs2_holder *gh, *tmp;
322 int ret;
323
324 restart:
325 list_for_each_entry_safe(gh, tmp, &gl->gl_holders, gh_list) {
326 if (test_bit(HIF_HOLDER, &gh->gh_iflags))
327 continue;
328 if (may_grant(gl, gh)) {
329 if (gh->gh_list.prev == &gl->gl_holders &&
330 glops->go_lock) {
331 spin_unlock(&gl->gl_spin);
332 /* FIXME: eliminate this eventually */
333 ret = glops->go_lock(gh);
334 spin_lock(&gl->gl_spin);
335 if (ret) {
336 if (ret == 1)
337 return 2;
338 gh->gh_error = ret;
339 list_del_init(&gh->gh_list);
340 trace_gfs2_glock_queue(gh, 0);
341 gfs2_holder_wake(gh);
342 goto restart;
343 }
344 set_bit(HIF_HOLDER, &gh->gh_iflags);
345 trace_gfs2_promote(gh, 1);
346 gfs2_holder_wake(gh);
347 goto restart;
348 }
349 set_bit(HIF_HOLDER, &gh->gh_iflags);
350 trace_gfs2_promote(gh, 0);
351 gfs2_holder_wake(gh);
352 continue;
353 }
354 if (gh->gh_list.prev == &gl->gl_holders)
355 return 1;
356 do_error(gl, 0);
357 break;
358 }
359 return 0;
360 }
361
362 /**
363 * find_first_waiter - find the first gh that's waiting for the glock
364 * @gl: the glock
365 */
366
367 static inline struct gfs2_holder *find_first_waiter(const struct gfs2_glock *gl)
368 {
369 struct gfs2_holder *gh;
370
371 list_for_each_entry(gh, &gl->gl_holders, gh_list) {
372 if (!test_bit(HIF_HOLDER, &gh->gh_iflags))
373 return gh;
374 }
375 return NULL;
376 }
377
378 /**
379 * state_change - record that the glock is now in a different state
380 * @gl: the glock
381 * @new_state the new state
382 *
383 */
384
385 static void state_change(struct gfs2_glock *gl, unsigned int new_state)
386 {
387 int held1, held2;
388
389 held1 = (gl->gl_state != LM_ST_UNLOCKED);
390 held2 = (new_state != LM_ST_UNLOCKED);
391
392 if (held1 != held2) {
393 GLOCK_BUG_ON(gl, __lockref_is_dead(&gl->gl_lockref));
394 if (held2)
395 gl->gl_lockref.count++;
396 else
397 gl->gl_lockref.count--;
398 }
399 if (held1 && held2 && list_empty(&gl->gl_holders))
400 clear_bit(GLF_QUEUED, &gl->gl_flags);
401
402 if (new_state != gl->gl_target)
403 /* shorten our minimum hold time */
404 gl->gl_hold_time = max(gl->gl_hold_time - GL_GLOCK_HOLD_DECR,
405 GL_GLOCK_MIN_HOLD);
406 gl->gl_state = new_state;
407 gl->gl_tchange = jiffies;
408 }
409
410 static void gfs2_demote_wake(struct gfs2_glock *gl)
411 {
412 gl->gl_demote_state = LM_ST_EXCLUSIVE;
413 clear_bit(GLF_DEMOTE, &gl->gl_flags);
414 smp_mb__after_atomic();
415 wake_up_bit(&gl->gl_flags, GLF_DEMOTE);
416 }
417
418 /**
419 * finish_xmote - The DLM has replied to one of our lock requests
420 * @gl: The glock
421 * @ret: The status from the DLM
422 *
423 */
424
425 static void finish_xmote(struct gfs2_glock *gl, unsigned int ret)
426 {
427 const struct gfs2_glock_operations *glops = gl->gl_ops;
428 struct gfs2_holder *gh;
429 unsigned state = ret & LM_OUT_ST_MASK;
430 int rv;
431
432 spin_lock(&gl->gl_spin);
433 trace_gfs2_glock_state_change(gl, state);
434 state_change(gl, state);
435 gh = find_first_waiter(gl);
436
437 /* Demote to UN request arrived during demote to SH or DF */
438 if (test_bit(GLF_DEMOTE_IN_PROGRESS, &gl->gl_flags) &&
439 state != LM_ST_UNLOCKED && gl->gl_demote_state == LM_ST_UNLOCKED)
440 gl->gl_target = LM_ST_UNLOCKED;
441
442 /* Check for state != intended state */
443 if (unlikely(state != gl->gl_target)) {
444 if (gh && !test_bit(GLF_DEMOTE_IN_PROGRESS, &gl->gl_flags)) {
445 /* move to back of queue and try next entry */
446 if (ret & LM_OUT_CANCELED) {
447 if ((gh->gh_flags & LM_FLAG_PRIORITY) == 0)
448 list_move_tail(&gh->gh_list, &gl->gl_holders);
449 gh = find_first_waiter(gl);
450 gl->gl_target = gh->gh_state;
451 goto retry;
452 }
453 /* Some error or failed "try lock" - report it */
454 if ((ret & LM_OUT_ERROR) ||
455 (gh->gh_flags & (LM_FLAG_TRY | LM_FLAG_TRY_1CB))) {
456 gl->gl_target = gl->gl_state;
457 do_error(gl, ret);
458 goto out;
459 }
460 }
461 switch(state) {
462 /* Unlocked due to conversion deadlock, try again */
463 case LM_ST_UNLOCKED:
464 retry:
465 do_xmote(gl, gh, gl->gl_target);
466 break;
467 /* Conversion fails, unlock and try again */
468 case LM_ST_SHARED:
469 case LM_ST_DEFERRED:
470 do_xmote(gl, gh, LM_ST_UNLOCKED);
471 break;
472 default: /* Everything else */
473 pr_err("wanted %u got %u\n", gl->gl_target, state);
474 GLOCK_BUG_ON(gl, 1);
475 }
476 spin_unlock(&gl->gl_spin);
477 return;
478 }
479
480 /* Fast path - we got what we asked for */
481 if (test_and_clear_bit(GLF_DEMOTE_IN_PROGRESS, &gl->gl_flags))
482 gfs2_demote_wake(gl);
483 if (state != LM_ST_UNLOCKED) {
484 if (glops->go_xmote_bh) {
485 spin_unlock(&gl->gl_spin);
486 rv = glops->go_xmote_bh(gl, gh);
487 spin_lock(&gl->gl_spin);
488 if (rv) {
489 do_error(gl, rv);
490 goto out;
491 }
492 }
493 rv = do_promote(gl);
494 if (rv == 2)
495 goto out_locked;
496 }
497 out:
498 clear_bit(GLF_LOCK, &gl->gl_flags);
499 out_locked:
500 spin_unlock(&gl->gl_spin);
501 }
502
503 /**
504 * do_xmote - Calls the DLM to change the state of a lock
505 * @gl: The lock state
506 * @gh: The holder (only for promotes)
507 * @target: The target lock state
508 *
509 */
510
511 static void do_xmote(struct gfs2_glock *gl, struct gfs2_holder *gh, unsigned int target)
512 __releases(&gl->gl_spin)
513 __acquires(&gl->gl_spin)
514 {
515 const struct gfs2_glock_operations *glops = gl->gl_ops;
516 struct gfs2_sbd *sdp = gl->gl_sbd;
517 unsigned int lck_flags = gh ? gh->gh_flags : 0;
518 int ret;
519
520 lck_flags &= (LM_FLAG_TRY | LM_FLAG_TRY_1CB | LM_FLAG_NOEXP |
521 LM_FLAG_PRIORITY);
522 GLOCK_BUG_ON(gl, gl->gl_state == target);
523 GLOCK_BUG_ON(gl, gl->gl_state == gl->gl_target);
524 if ((target == LM_ST_UNLOCKED || target == LM_ST_DEFERRED) &&
525 glops->go_inval) {
526 set_bit(GLF_INVALIDATE_IN_PROGRESS, &gl->gl_flags);
527 do_error(gl, 0); /* Fail queued try locks */
528 }
529 gl->gl_req = target;
530 set_bit(GLF_BLOCKING, &gl->gl_flags);
531 if ((gl->gl_req == LM_ST_UNLOCKED) ||
532 (gl->gl_state == LM_ST_EXCLUSIVE) ||
533 (lck_flags & (LM_FLAG_TRY|LM_FLAG_TRY_1CB)))
534 clear_bit(GLF_BLOCKING, &gl->gl_flags);
535 spin_unlock(&gl->gl_spin);
536 if (glops->go_sync)
537 glops->go_sync(gl);
538 if (test_bit(GLF_INVALIDATE_IN_PROGRESS, &gl->gl_flags))
539 glops->go_inval(gl, target == LM_ST_DEFERRED ? 0 : DIO_METADATA);
540 clear_bit(GLF_INVALIDATE_IN_PROGRESS, &gl->gl_flags);
541
542 gfs2_glock_hold(gl);
543 if (sdp->sd_lockstruct.ls_ops->lm_lock) {
544 /* lock_dlm */
545 ret = sdp->sd_lockstruct.ls_ops->lm_lock(gl, target, lck_flags);
546 if (ret) {
547 pr_err("lm_lock ret %d\n", ret);
548 GLOCK_BUG_ON(gl, 1);
549 }
550 } else { /* lock_nolock */
551 finish_xmote(gl, target);
552 if (queue_delayed_work(glock_workqueue, &gl->gl_work, 0) == 0)
553 gfs2_glock_put(gl);
554 }
555
556 spin_lock(&gl->gl_spin);
557 }
558
559 /**
560 * find_first_holder - find the first "holder" gh
561 * @gl: the glock
562 */
563
564 static inline struct gfs2_holder *find_first_holder(const struct gfs2_glock *gl)
565 {
566 struct gfs2_holder *gh;
567
568 if (!list_empty(&gl->gl_holders)) {
569 gh = list_entry(gl->gl_holders.next, struct gfs2_holder, gh_list);
570 if (test_bit(HIF_HOLDER, &gh->gh_iflags))
571 return gh;
572 }
573 return NULL;
574 }
575
576 /**
577 * run_queue - do all outstanding tasks related to a glock
578 * @gl: The glock in question
579 * @nonblock: True if we must not block in run_queue
580 *
581 */
582
583 static void run_queue(struct gfs2_glock *gl, const int nonblock)
584 __releases(&gl->gl_spin)
585 __acquires(&gl->gl_spin)
586 {
587 struct gfs2_holder *gh = NULL;
588 int ret;
589
590 if (test_and_set_bit(GLF_LOCK, &gl->gl_flags))
591 return;
592
593 GLOCK_BUG_ON(gl, test_bit(GLF_DEMOTE_IN_PROGRESS, &gl->gl_flags));
594
595 if (test_bit(GLF_DEMOTE, &gl->gl_flags) &&
596 gl->gl_demote_state != gl->gl_state) {
597 if (find_first_holder(gl))
598 goto out_unlock;
599 if (nonblock)
600 goto out_sched;
601 set_bit(GLF_DEMOTE_IN_PROGRESS, &gl->gl_flags);
602 GLOCK_BUG_ON(gl, gl->gl_demote_state == LM_ST_EXCLUSIVE);
603 gl->gl_target = gl->gl_demote_state;
604 } else {
605 if (test_bit(GLF_DEMOTE, &gl->gl_flags))
606 gfs2_demote_wake(gl);
607 ret = do_promote(gl);
608 if (ret == 0)
609 goto out_unlock;
610 if (ret == 2)
611 goto out;
612 gh = find_first_waiter(gl);
613 gl->gl_target = gh->gh_state;
614 if (!(gh->gh_flags & (LM_FLAG_TRY | LM_FLAG_TRY_1CB)))
615 do_error(gl, 0); /* Fail queued try locks */
616 }
617 do_xmote(gl, gh, gl->gl_target);
618 out:
619 return;
620
621 out_sched:
622 clear_bit(GLF_LOCK, &gl->gl_flags);
623 smp_mb__after_atomic();
624 gl->gl_lockref.count++;
625 if (queue_delayed_work(glock_workqueue, &gl->gl_work, 0) == 0)
626 gl->gl_lockref.count--;
627 return;
628
629 out_unlock:
630 clear_bit(GLF_LOCK, &gl->gl_flags);
631 smp_mb__after_atomic();
632 return;
633 }
634
635 static void delete_work_func(struct work_struct *work)
636 {
637 struct gfs2_glock *gl = container_of(work, struct gfs2_glock, gl_delete);
638 struct gfs2_sbd *sdp = gl->gl_sbd;
639 struct gfs2_inode *ip;
640 struct inode *inode;
641 u64 no_addr = gl->gl_name.ln_number;
642
643 ip = gl->gl_object;
644 /* Note: Unsafe to dereference ip as we don't hold right refs/locks */
645
646 if (ip)
647 inode = gfs2_ilookup(sdp->sd_vfs, no_addr, 1);
648 else
649 inode = gfs2_lookup_by_inum(sdp, no_addr, NULL, GFS2_BLKST_UNLINKED);
650 if (inode && !IS_ERR(inode)) {
651 d_prune_aliases(inode);
652 iput(inode);
653 }
654 gfs2_glock_put(gl);
655 }
656
657 static void glock_work_func(struct work_struct *work)
658 {
659 unsigned long delay = 0;
660 struct gfs2_glock *gl = container_of(work, struct gfs2_glock, gl_work.work);
661 int drop_ref = 0;
662
663 if (test_and_clear_bit(GLF_REPLY_PENDING, &gl->gl_flags)) {
664 finish_xmote(gl, gl->gl_reply);
665 drop_ref = 1;
666 }
667 spin_lock(&gl->gl_spin);
668 if (test_bit(GLF_PENDING_DEMOTE, &gl->gl_flags) &&
669 gl->gl_state != LM_ST_UNLOCKED &&
670 gl->gl_demote_state != LM_ST_EXCLUSIVE) {
671 unsigned long holdtime, now = jiffies;
672
673 holdtime = gl->gl_tchange + gl->gl_hold_time;
674 if (time_before(now, holdtime))
675 delay = holdtime - now;
676
677 if (!delay) {
678 clear_bit(GLF_PENDING_DEMOTE, &gl->gl_flags);
679 set_bit(GLF_DEMOTE, &gl->gl_flags);
680 }
681 }
682 run_queue(gl, 0);
683 spin_unlock(&gl->gl_spin);
684 if (!delay)
685 gfs2_glock_put(gl);
686 else {
687 if (gl->gl_name.ln_type != LM_TYPE_INODE)
688 delay = 0;
689 if (queue_delayed_work(glock_workqueue, &gl->gl_work, delay) == 0)
690 gfs2_glock_put(gl);
691 }
692 if (drop_ref)
693 gfs2_glock_put(gl);
694 }
695
696 /**
697 * gfs2_glock_get() - Get a glock, or create one if one doesn't exist
698 * @sdp: The GFS2 superblock
699 * @number: the lock number
700 * @glops: The glock_operations to use
701 * @create: If 0, don't create the glock if it doesn't exist
702 * @glp: the glock is returned here
703 *
704 * This does not lock a glock, just finds/creates structures for one.
705 *
706 * Returns: errno
707 */
708
709 int gfs2_glock_get(struct gfs2_sbd *sdp, u64 number,
710 const struct gfs2_glock_operations *glops, int create,
711 struct gfs2_glock **glp)
712 {
713 struct super_block *s = sdp->sd_vfs;
714 struct lm_lockname name = { .ln_number = number, .ln_type = glops->go_type };
715 struct gfs2_glock *gl, *tmp;
716 unsigned int hash = gl_hash(sdp, &name);
717 struct address_space *mapping;
718 struct kmem_cache *cachep;
719
720 rcu_read_lock();
721 gl = search_bucket(hash, sdp, &name);
722 rcu_read_unlock();
723
724 *glp = gl;
725 if (gl)
726 return 0;
727 if (!create)
728 return -ENOENT;
729
730 if (glops->go_flags & GLOF_ASPACE)
731 cachep = gfs2_glock_aspace_cachep;
732 else
733 cachep = gfs2_glock_cachep;
734 gl = kmem_cache_alloc(cachep, GFP_NOFS);
735 if (!gl)
736 return -ENOMEM;
737
738 memset(&gl->gl_lksb, 0, sizeof(struct dlm_lksb));
739
740 if (glops->go_flags & GLOF_LVB) {
741 gl->gl_lksb.sb_lvbptr = kzalloc(GFS2_MIN_LVB_SIZE, GFP_NOFS);
742 if (!gl->gl_lksb.sb_lvbptr) {
743 kmem_cache_free(cachep, gl);
744 return -ENOMEM;
745 }
746 }
747
748 atomic_inc(&sdp->sd_glock_disposal);
749 gl->gl_sbd = sdp;
750 gl->gl_flags = 0;
751 gl->gl_name = name;
752 gl->gl_lockref.count = 1;
753 gl->gl_state = LM_ST_UNLOCKED;
754 gl->gl_target = LM_ST_UNLOCKED;
755 gl->gl_demote_state = LM_ST_EXCLUSIVE;
756 gl->gl_hash = hash;
757 gl->gl_ops = glops;
758 gl->gl_dstamp = ktime_set(0, 0);
759 preempt_disable();
760 /* We use the global stats to estimate the initial per-glock stats */
761 gl->gl_stats = this_cpu_ptr(sdp->sd_lkstats)->lkstats[glops->go_type];
762 preempt_enable();
763 gl->gl_stats.stats[GFS2_LKS_DCOUNT] = 0;
764 gl->gl_stats.stats[GFS2_LKS_QCOUNT] = 0;
765 gl->gl_tchange = jiffies;
766 gl->gl_object = NULL;
767 gl->gl_hold_time = GL_GLOCK_DFT_HOLD;
768 INIT_DELAYED_WORK(&gl->gl_work, glock_work_func);
769 INIT_WORK(&gl->gl_delete, delete_work_func);
770
771 mapping = gfs2_glock2aspace(gl);
772 if (mapping) {
773 mapping->a_ops = &gfs2_meta_aops;
774 mapping->host = s->s_bdev->bd_inode;
775 mapping->flags = 0;
776 mapping_set_gfp_mask(mapping, GFP_NOFS);
777 mapping->private_data = NULL;
778 mapping->backing_dev_info = s->s_bdi;
779 mapping->writeback_index = 0;
780 }
781
782 spin_lock_bucket(hash);
783 tmp = search_bucket(hash, sdp, &name);
784 if (tmp) {
785 spin_unlock_bucket(hash);
786 kfree(gl->gl_lksb.sb_lvbptr);
787 kmem_cache_free(cachep, gl);
788 atomic_dec(&sdp->sd_glock_disposal);
789 gl = tmp;
790 } else {
791 hlist_bl_add_head_rcu(&gl->gl_list, &gl_hash_table[hash]);
792 spin_unlock_bucket(hash);
793 }
794
795 *glp = gl;
796
797 return 0;
798 }
799
800 /**
801 * gfs2_holder_init - initialize a struct gfs2_holder in the default way
802 * @gl: the glock
803 * @state: the state we're requesting
804 * @flags: the modifier flags
805 * @gh: the holder structure
806 *
807 */
808
809 void gfs2_holder_init(struct gfs2_glock *gl, unsigned int state, unsigned flags,
810 struct gfs2_holder *gh)
811 {
812 INIT_LIST_HEAD(&gh->gh_list);
813 gh->gh_gl = gl;
814 gh->gh_ip = _RET_IP_;
815 gh->gh_owner_pid = get_pid(task_pid(current));
816 gh->gh_state = state;
817 gh->gh_flags = flags;
818 gh->gh_error = 0;
819 gh->gh_iflags = 0;
820 gfs2_glock_hold(gl);
821 }
822
823 /**
824 * gfs2_holder_reinit - reinitialize a struct gfs2_holder so we can requeue it
825 * @state: the state we're requesting
826 * @flags: the modifier flags
827 * @gh: the holder structure
828 *
829 * Don't mess with the glock.
830 *
831 */
832
833 void gfs2_holder_reinit(unsigned int state, unsigned flags, struct gfs2_holder *gh)
834 {
835 gh->gh_state = state;
836 gh->gh_flags = flags;
837 gh->gh_iflags = 0;
838 gh->gh_ip = _RET_IP_;
839 put_pid(gh->gh_owner_pid);
840 gh->gh_owner_pid = get_pid(task_pid(current));
841 }
842
843 /**
844 * gfs2_holder_uninit - uninitialize a holder structure (drop glock reference)
845 * @gh: the holder structure
846 *
847 */
848
849 void gfs2_holder_uninit(struct gfs2_holder *gh)
850 {
851 put_pid(gh->gh_owner_pid);
852 gfs2_glock_put(gh->gh_gl);
853 gh->gh_gl = NULL;
854 gh->gh_ip = 0;
855 }
856
857 /**
858 * gfs2_glock_wait - wait on a glock acquisition
859 * @gh: the glock holder
860 *
861 * Returns: 0 on success
862 */
863
864 int gfs2_glock_wait(struct gfs2_holder *gh)
865 {
866 unsigned long time1 = jiffies;
867
868 might_sleep();
869 wait_on_bit(&gh->gh_iflags, HIF_WAIT, TASK_UNINTERRUPTIBLE);
870 if (time_after(jiffies, time1 + HZ)) /* have we waited > a second? */
871 /* Lengthen the minimum hold time. */
872 gh->gh_gl->gl_hold_time = min(gh->gh_gl->gl_hold_time +
873 GL_GLOCK_HOLD_INCR,
874 GL_GLOCK_MAX_HOLD);
875 return gh->gh_error;
876 }
877
878 /**
879 * handle_callback - process a demote request
880 * @gl: the glock
881 * @state: the state the caller wants us to change to
882 *
883 * There are only two requests that we are going to see in actual
884 * practise: LM_ST_SHARED and LM_ST_UNLOCKED
885 */
886
887 static void handle_callback(struct gfs2_glock *gl, unsigned int state,
888 unsigned long delay, bool remote)
889 {
890 int bit = delay ? GLF_PENDING_DEMOTE : GLF_DEMOTE;
891
892 set_bit(bit, &gl->gl_flags);
893 if (gl->gl_demote_state == LM_ST_EXCLUSIVE) {
894 gl->gl_demote_state = state;
895 gl->gl_demote_time = jiffies;
896 } else if (gl->gl_demote_state != LM_ST_UNLOCKED &&
897 gl->gl_demote_state != state) {
898 gl->gl_demote_state = LM_ST_UNLOCKED;
899 }
900 if (gl->gl_ops->go_callback)
901 gl->gl_ops->go_callback(gl, remote);
902 trace_gfs2_demote_rq(gl, remote);
903 }
904
905 void gfs2_print_dbg(struct seq_file *seq, const char *fmt, ...)
906 {
907 struct va_format vaf;
908 va_list args;
909
910 va_start(args, fmt);
911
912 if (seq) {
913 seq_vprintf(seq, fmt, args);
914 } else {
915 vaf.fmt = fmt;
916 vaf.va = &args;
917
918 pr_err("%pV", &vaf);
919 }
920
921 va_end(args);
922 }
923
924 /**
925 * add_to_queue - Add a holder to the wait queue (but look for recursion)
926 * @gh: the holder structure to add
927 *
928 * Eventually we should move the recursive locking trap to a
929 * debugging option or something like that. This is the fast
930 * path and needs to have the minimum number of distractions.
931 *
932 */
933
934 static inline void add_to_queue(struct gfs2_holder *gh)
935 __releases(&gl->gl_spin)
936 __acquires(&gl->gl_spin)
937 {
938 struct gfs2_glock *gl = gh->gh_gl;
939 struct gfs2_sbd *sdp = gl->gl_sbd;
940 struct list_head *insert_pt = NULL;
941 struct gfs2_holder *gh2;
942 int try_futile = 0;
943
944 BUG_ON(gh->gh_owner_pid == NULL);
945 if (test_and_set_bit(HIF_WAIT, &gh->gh_iflags))
946 BUG();
947
948 if (gh->gh_flags & (LM_FLAG_TRY | LM_FLAG_TRY_1CB)) {
949 if (test_bit(GLF_LOCK, &gl->gl_flags))
950 try_futile = !may_grant(gl, gh);
951 if (test_bit(GLF_INVALIDATE_IN_PROGRESS, &gl->gl_flags))
952 goto fail;
953 }
954
955 list_for_each_entry(gh2, &gl->gl_holders, gh_list) {
956 if (unlikely(gh2->gh_owner_pid == gh->gh_owner_pid &&
957 (gh->gh_gl->gl_ops->go_type != LM_TYPE_FLOCK)))
958 goto trap_recursive;
959 if (try_futile &&
960 !(gh2->gh_flags & (LM_FLAG_TRY | LM_FLAG_TRY_1CB))) {
961 fail:
962 gh->gh_error = GLR_TRYFAILED;
963 gfs2_holder_wake(gh);
964 return;
965 }
966 if (test_bit(HIF_HOLDER, &gh2->gh_iflags))
967 continue;
968 if (unlikely((gh->gh_flags & LM_FLAG_PRIORITY) && !insert_pt))
969 insert_pt = &gh2->gh_list;
970 }
971 set_bit(GLF_QUEUED, &gl->gl_flags);
972 trace_gfs2_glock_queue(gh, 1);
973 gfs2_glstats_inc(gl, GFS2_LKS_QCOUNT);
974 gfs2_sbstats_inc(gl, GFS2_LKS_QCOUNT);
975 if (likely(insert_pt == NULL)) {
976 list_add_tail(&gh->gh_list, &gl->gl_holders);
977 if (unlikely(gh->gh_flags & LM_FLAG_PRIORITY))
978 goto do_cancel;
979 return;
980 }
981 list_add_tail(&gh->gh_list, insert_pt);
982 do_cancel:
983 gh = list_entry(gl->gl_holders.next, struct gfs2_holder, gh_list);
984 if (!(gh->gh_flags & LM_FLAG_PRIORITY)) {
985 spin_unlock(&gl->gl_spin);
986 if (sdp->sd_lockstruct.ls_ops->lm_cancel)
987 sdp->sd_lockstruct.ls_ops->lm_cancel(gl);
988 spin_lock(&gl->gl_spin);
989 }
990 return;
991
992 trap_recursive:
993 pr_err("original: %pSR\n", (void *)gh2->gh_ip);
994 pr_err("pid: %d\n", pid_nr(gh2->gh_owner_pid));
995 pr_err("lock type: %d req lock state : %d\n",
996 gh2->gh_gl->gl_name.ln_type, gh2->gh_state);
997 pr_err("new: %pSR\n", (void *)gh->gh_ip);
998 pr_err("pid: %d\n", pid_nr(gh->gh_owner_pid));
999 pr_err("lock type: %d req lock state : %d\n",
1000 gh->gh_gl->gl_name.ln_type, gh->gh_state);
1001 gfs2_dump_glock(NULL, gl);
1002 BUG();
1003 }
1004
1005 /**
1006 * gfs2_glock_nq - enqueue a struct gfs2_holder onto a glock (acquire a glock)
1007 * @gh: the holder structure
1008 *
1009 * if (gh->gh_flags & GL_ASYNC), this never returns an error
1010 *
1011 * Returns: 0, GLR_TRYFAILED, or errno on failure
1012 */
1013
1014 int gfs2_glock_nq(struct gfs2_holder *gh)
1015 {
1016 struct gfs2_glock *gl = gh->gh_gl;
1017 struct gfs2_sbd *sdp = gl->gl_sbd;
1018 int error = 0;
1019
1020 if (unlikely(test_bit(SDF_SHUTDOWN, &sdp->sd_flags)))
1021 return -EIO;
1022
1023 if (test_bit(GLF_LRU, &gl->gl_flags))
1024 gfs2_glock_remove_from_lru(gl);
1025
1026 spin_lock(&gl->gl_spin);
1027 add_to_queue(gh);
1028 if (unlikely((LM_FLAG_NOEXP & gh->gh_flags) &&
1029 test_and_clear_bit(GLF_FROZEN, &gl->gl_flags))) {
1030 set_bit(GLF_REPLY_PENDING, &gl->gl_flags);
1031 gl->gl_lockref.count++;
1032 if (queue_delayed_work(glock_workqueue, &gl->gl_work, 0) == 0)
1033 gl->gl_lockref.count--;
1034 }
1035 run_queue(gl, 1);
1036 spin_unlock(&gl->gl_spin);
1037
1038 if (!(gh->gh_flags & GL_ASYNC))
1039 error = gfs2_glock_wait(gh);
1040
1041 return error;
1042 }
1043
1044 /**
1045 * gfs2_glock_poll - poll to see if an async request has been completed
1046 * @gh: the holder
1047 *
1048 * Returns: 1 if the request is ready to be gfs2_glock_wait()ed on
1049 */
1050
1051 int gfs2_glock_poll(struct gfs2_holder *gh)
1052 {
1053 return test_bit(HIF_WAIT, &gh->gh_iflags) ? 0 : 1;
1054 }
1055
1056 /**
1057 * gfs2_glock_dq - dequeue a struct gfs2_holder from a glock (release a glock)
1058 * @gh: the glock holder
1059 *
1060 */
1061
1062 void gfs2_glock_dq(struct gfs2_holder *gh)
1063 {
1064 struct gfs2_glock *gl = gh->gh_gl;
1065 const struct gfs2_glock_operations *glops = gl->gl_ops;
1066 unsigned delay = 0;
1067 int fast_path = 0;
1068
1069 spin_lock(&gl->gl_spin);
1070 if (gh->gh_flags & GL_NOCACHE)
1071 handle_callback(gl, LM_ST_UNLOCKED, 0, false);
1072
1073 list_del_init(&gh->gh_list);
1074 if (find_first_holder(gl) == NULL) {
1075 if (glops->go_unlock) {
1076 GLOCK_BUG_ON(gl, test_and_set_bit(GLF_LOCK, &gl->gl_flags));
1077 spin_unlock(&gl->gl_spin);
1078 glops->go_unlock(gh);
1079 spin_lock(&gl->gl_spin);
1080 clear_bit(GLF_LOCK, &gl->gl_flags);
1081 }
1082 if (list_empty(&gl->gl_holders) &&
1083 !test_bit(GLF_PENDING_DEMOTE, &gl->gl_flags) &&
1084 !test_bit(GLF_DEMOTE, &gl->gl_flags))
1085 fast_path = 1;
1086 }
1087 if (!test_bit(GLF_LFLUSH, &gl->gl_flags) && demote_ok(gl))
1088 gfs2_glock_add_to_lru(gl);
1089
1090 trace_gfs2_glock_queue(gh, 0);
1091 spin_unlock(&gl->gl_spin);
1092 if (likely(fast_path))
1093 return;
1094
1095 gfs2_glock_hold(gl);
1096 if (test_bit(GLF_PENDING_DEMOTE, &gl->gl_flags) &&
1097 !test_bit(GLF_DEMOTE, &gl->gl_flags) &&
1098 gl->gl_name.ln_type == LM_TYPE_INODE)
1099 delay = gl->gl_hold_time;
1100 if (queue_delayed_work(glock_workqueue, &gl->gl_work, delay) == 0)
1101 gfs2_glock_put(gl);
1102 }
1103
1104 void gfs2_glock_dq_wait(struct gfs2_holder *gh)
1105 {
1106 struct gfs2_glock *gl = gh->gh_gl;
1107 gfs2_glock_dq(gh);
1108 might_sleep();
1109 wait_on_bit(&gl->gl_flags, GLF_DEMOTE, TASK_UNINTERRUPTIBLE);
1110 }
1111
1112 /**
1113 * gfs2_glock_dq_uninit - dequeue a holder from a glock and initialize it
1114 * @gh: the holder structure
1115 *
1116 */
1117
1118 void gfs2_glock_dq_uninit(struct gfs2_holder *gh)
1119 {
1120 gfs2_glock_dq(gh);
1121 gfs2_holder_uninit(gh);
1122 }
1123
1124 /**
1125 * gfs2_glock_nq_num - acquire a glock based on lock number
1126 * @sdp: the filesystem
1127 * @number: the lock number
1128 * @glops: the glock operations for the type of glock
1129 * @state: the state to acquire the glock in
1130 * @flags: modifier flags for the acquisition
1131 * @gh: the struct gfs2_holder
1132 *
1133 * Returns: errno
1134 */
1135
1136 int gfs2_glock_nq_num(struct gfs2_sbd *sdp, u64 number,
1137 const struct gfs2_glock_operations *glops,
1138 unsigned int state, int flags, struct gfs2_holder *gh)
1139 {
1140 struct gfs2_glock *gl;
1141 int error;
1142
1143 error = gfs2_glock_get(sdp, number, glops, CREATE, &gl);
1144 if (!error) {
1145 error = gfs2_glock_nq_init(gl, state, flags, gh);
1146 gfs2_glock_put(gl);
1147 }
1148
1149 return error;
1150 }
1151
1152 /**
1153 * glock_compare - Compare two struct gfs2_glock structures for sorting
1154 * @arg_a: the first structure
1155 * @arg_b: the second structure
1156 *
1157 */
1158
1159 static int glock_compare(const void *arg_a, const void *arg_b)
1160 {
1161 const struct gfs2_holder *gh_a = *(const struct gfs2_holder **)arg_a;
1162 const struct gfs2_holder *gh_b = *(const struct gfs2_holder **)arg_b;
1163 const struct lm_lockname *a = &gh_a->gh_gl->gl_name;
1164 const struct lm_lockname *b = &gh_b->gh_gl->gl_name;
1165
1166 if (a->ln_number > b->ln_number)
1167 return 1;
1168 if (a->ln_number < b->ln_number)
1169 return -1;
1170 BUG_ON(gh_a->gh_gl->gl_ops->go_type == gh_b->gh_gl->gl_ops->go_type);
1171 return 0;
1172 }
1173
1174 /**
1175 * nq_m_sync - synchonously acquire more than one glock in deadlock free order
1176 * @num_gh: the number of structures
1177 * @ghs: an array of struct gfs2_holder structures
1178 *
1179 * Returns: 0 on success (all glocks acquired),
1180 * errno on failure (no glocks acquired)
1181 */
1182
1183 static int nq_m_sync(unsigned int num_gh, struct gfs2_holder *ghs,
1184 struct gfs2_holder **p)
1185 {
1186 unsigned int x;
1187 int error = 0;
1188
1189 for (x = 0; x < num_gh; x++)
1190 p[x] = &ghs[x];
1191
1192 sort(p, num_gh, sizeof(struct gfs2_holder *), glock_compare, NULL);
1193
1194 for (x = 0; x < num_gh; x++) {
1195 p[x]->gh_flags &= ~(LM_FLAG_TRY | GL_ASYNC);
1196
1197 error = gfs2_glock_nq(p[x]);
1198 if (error) {
1199 while (x--)
1200 gfs2_glock_dq(p[x]);
1201 break;
1202 }
1203 }
1204
1205 return error;
1206 }
1207
1208 /**
1209 * gfs2_glock_nq_m - acquire multiple glocks
1210 * @num_gh: the number of structures
1211 * @ghs: an array of struct gfs2_holder structures
1212 *
1213 *
1214 * Returns: 0 on success (all glocks acquired),
1215 * errno on failure (no glocks acquired)
1216 */
1217
1218 int gfs2_glock_nq_m(unsigned int num_gh, struct gfs2_holder *ghs)
1219 {
1220 struct gfs2_holder *tmp[4];
1221 struct gfs2_holder **pph = tmp;
1222 int error = 0;
1223
1224 switch(num_gh) {
1225 case 0:
1226 return 0;
1227 case 1:
1228 ghs->gh_flags &= ~(LM_FLAG_TRY | GL_ASYNC);
1229 return gfs2_glock_nq(ghs);
1230 default:
1231 if (num_gh <= 4)
1232 break;
1233 pph = kmalloc(num_gh * sizeof(struct gfs2_holder *), GFP_NOFS);
1234 if (!pph)
1235 return -ENOMEM;
1236 }
1237
1238 error = nq_m_sync(num_gh, ghs, pph);
1239
1240 if (pph != tmp)
1241 kfree(pph);
1242
1243 return error;
1244 }
1245
1246 /**
1247 * gfs2_glock_dq_m - release multiple glocks
1248 * @num_gh: the number of structures
1249 * @ghs: an array of struct gfs2_holder structures
1250 *
1251 */
1252
1253 void gfs2_glock_dq_m(unsigned int num_gh, struct gfs2_holder *ghs)
1254 {
1255 while (num_gh--)
1256 gfs2_glock_dq(&ghs[num_gh]);
1257 }
1258
1259 void gfs2_glock_cb(struct gfs2_glock *gl, unsigned int state)
1260 {
1261 unsigned long delay = 0;
1262 unsigned long holdtime;
1263 unsigned long now = jiffies;
1264
1265 gfs2_glock_hold(gl);
1266 holdtime = gl->gl_tchange + gl->gl_hold_time;
1267 if (test_bit(GLF_QUEUED, &gl->gl_flags) &&
1268 gl->gl_name.ln_type == LM_TYPE_INODE) {
1269 if (time_before(now, holdtime))
1270 delay = holdtime - now;
1271 if (test_bit(GLF_REPLY_PENDING, &gl->gl_flags))
1272 delay = gl->gl_hold_time;
1273 }
1274
1275 spin_lock(&gl->gl_spin);
1276 handle_callback(gl, state, delay, true);
1277 spin_unlock(&gl->gl_spin);
1278 if (queue_delayed_work(glock_workqueue, &gl->gl_work, delay) == 0)
1279 gfs2_glock_put(gl);
1280 }
1281
1282 /**
1283 * gfs2_should_freeze - Figure out if glock should be frozen
1284 * @gl: The glock in question
1285 *
1286 * Glocks are not frozen if (a) the result of the dlm operation is
1287 * an error, (b) the locking operation was an unlock operation or
1288 * (c) if there is a "noexp" flagged request anywhere in the queue
1289 *
1290 * Returns: 1 if freezing should occur, 0 otherwise
1291 */
1292
1293 static int gfs2_should_freeze(const struct gfs2_glock *gl)
1294 {
1295 const struct gfs2_holder *gh;
1296
1297 if (gl->gl_reply & ~LM_OUT_ST_MASK)
1298 return 0;
1299 if (gl->gl_target == LM_ST_UNLOCKED)
1300 return 0;
1301
1302 list_for_each_entry(gh, &gl->gl_holders, gh_list) {
1303 if (test_bit(HIF_HOLDER, &gh->gh_iflags))
1304 continue;
1305 if (LM_FLAG_NOEXP & gh->gh_flags)
1306 return 0;
1307 }
1308
1309 return 1;
1310 }
1311
1312 /**
1313 * gfs2_glock_complete - Callback used by locking
1314 * @gl: Pointer to the glock
1315 * @ret: The return value from the dlm
1316 *
1317 * The gl_reply field is under the gl_spin lock so that it is ok
1318 * to use a bitfield shared with other glock state fields.
1319 */
1320
1321 void gfs2_glock_complete(struct gfs2_glock *gl, int ret)
1322 {
1323 struct lm_lockstruct *ls = &gl->gl_sbd->sd_lockstruct;
1324
1325 spin_lock(&gl->gl_spin);
1326 gl->gl_reply = ret;
1327
1328 if (unlikely(test_bit(DFL_BLOCK_LOCKS, &ls->ls_recover_flags))) {
1329 if (gfs2_should_freeze(gl)) {
1330 set_bit(GLF_FROZEN, &gl->gl_flags);
1331 spin_unlock(&gl->gl_spin);
1332 return;
1333 }
1334 }
1335
1336 gl->gl_lockref.count++;
1337 set_bit(GLF_REPLY_PENDING, &gl->gl_flags);
1338 spin_unlock(&gl->gl_spin);
1339
1340 if (queue_delayed_work(glock_workqueue, &gl->gl_work, 0) == 0)
1341 gfs2_glock_put(gl);
1342 }
1343
1344 static int glock_cmp(void *priv, struct list_head *a, struct list_head *b)
1345 {
1346 struct gfs2_glock *gla, *glb;
1347
1348 gla = list_entry(a, struct gfs2_glock, gl_lru);
1349 glb = list_entry(b, struct gfs2_glock, gl_lru);
1350
1351 if (gla->gl_name.ln_number > glb->gl_name.ln_number)
1352 return 1;
1353 if (gla->gl_name.ln_number < glb->gl_name.ln_number)
1354 return -1;
1355
1356 return 0;
1357 }
1358
1359 /**
1360 * gfs2_dispose_glock_lru - Demote a list of glocks
1361 * @list: The list to dispose of
1362 *
1363 * Disposing of glocks may involve disk accesses, so that here we sort
1364 * the glocks by number (i.e. disk location of the inodes) so that if
1365 * there are any such accesses, they'll be sent in order (mostly).
1366 *
1367 * Must be called under the lru_lock, but may drop and retake this
1368 * lock. While the lru_lock is dropped, entries may vanish from the
1369 * list, but no new entries will appear on the list (since it is
1370 * private)
1371 */
1372
1373 static void gfs2_dispose_glock_lru(struct list_head *list)
1374 __releases(&lru_lock)
1375 __acquires(&lru_lock)
1376 {
1377 struct gfs2_glock *gl;
1378
1379 list_sort(NULL, list, glock_cmp);
1380
1381 while(!list_empty(list)) {
1382 gl = list_entry(list->next, struct gfs2_glock, gl_lru);
1383 list_del_init(&gl->gl_lru);
1384 if (!spin_trylock(&gl->gl_spin)) {
1385 add_back_to_lru:
1386 list_add(&gl->gl_lru, &lru_list);
1387 atomic_inc(&lru_count);
1388 continue;
1389 }
1390 if (test_and_set_bit(GLF_LOCK, &gl->gl_flags)) {
1391 spin_unlock(&gl->gl_spin);
1392 goto add_back_to_lru;
1393 }
1394 clear_bit(GLF_LRU, &gl->gl_flags);
1395 gl->gl_lockref.count++;
1396 if (demote_ok(gl))
1397 handle_callback(gl, LM_ST_UNLOCKED, 0, false);
1398 WARN_ON(!test_and_clear_bit(GLF_LOCK, &gl->gl_flags));
1399 if (queue_delayed_work(glock_workqueue, &gl->gl_work, 0) == 0)
1400 gl->gl_lockref.count--;
1401 spin_unlock(&gl->gl_spin);
1402 cond_resched_lock(&lru_lock);
1403 }
1404 }
1405
1406 /**
1407 * gfs2_scan_glock_lru - Scan the LRU looking for locks to demote
1408 * @nr: The number of entries to scan
1409 *
1410 * This function selects the entries on the LRU which are able to
1411 * be demoted, and then kicks off the process by calling
1412 * gfs2_dispose_glock_lru() above.
1413 */
1414
1415 static long gfs2_scan_glock_lru(int nr)
1416 {
1417 struct gfs2_glock *gl;
1418 LIST_HEAD(skipped);
1419 LIST_HEAD(dispose);
1420 long freed = 0;
1421
1422 spin_lock(&lru_lock);
1423 while ((nr-- >= 0) && !list_empty(&lru_list)) {
1424 gl = list_entry(lru_list.next, struct gfs2_glock, gl_lru);
1425
1426 /* Test for being demotable */
1427 if (!test_bit(GLF_LOCK, &gl->gl_flags)) {
1428 list_move(&gl->gl_lru, &dispose);
1429 atomic_dec(&lru_count);
1430 freed++;
1431 continue;
1432 }
1433
1434 list_move(&gl->gl_lru, &skipped);
1435 }
1436 list_splice(&skipped, &lru_list);
1437 if (!list_empty(&dispose))
1438 gfs2_dispose_glock_lru(&dispose);
1439 spin_unlock(&lru_lock);
1440
1441 return freed;
1442 }
1443
1444 static unsigned long gfs2_glock_shrink_scan(struct shrinker *shrink,
1445 struct shrink_control *sc)
1446 {
1447 if (!(sc->gfp_mask & __GFP_FS))
1448 return SHRINK_STOP;
1449 return gfs2_scan_glock_lru(sc->nr_to_scan);
1450 }
1451
1452 static unsigned long gfs2_glock_shrink_count(struct shrinker *shrink,
1453 struct shrink_control *sc)
1454 {
1455 return vfs_pressure_ratio(atomic_read(&lru_count));
1456 }
1457
1458 static struct shrinker glock_shrinker = {
1459 .seeks = DEFAULT_SEEKS,
1460 .count_objects = gfs2_glock_shrink_count,
1461 .scan_objects = gfs2_glock_shrink_scan,
1462 };
1463
1464 /**
1465 * examine_bucket - Call a function for glock in a hash bucket
1466 * @examiner: the function
1467 * @sdp: the filesystem
1468 * @bucket: the bucket
1469 *
1470 */
1471
1472 static void examine_bucket(glock_examiner examiner, const struct gfs2_sbd *sdp,
1473 unsigned int hash)
1474 {
1475 struct gfs2_glock *gl;
1476 struct hlist_bl_head *head = &gl_hash_table[hash];
1477 struct hlist_bl_node *pos;
1478
1479 rcu_read_lock();
1480 hlist_bl_for_each_entry_rcu(gl, pos, head, gl_list) {
1481 if ((gl->gl_sbd == sdp) && lockref_get_not_dead(&gl->gl_lockref))
1482 examiner(gl);
1483 }
1484 rcu_read_unlock();
1485 cond_resched();
1486 }
1487
1488 static void glock_hash_walk(glock_examiner examiner, const struct gfs2_sbd *sdp)
1489 {
1490 unsigned x;
1491
1492 for (x = 0; x < GFS2_GL_HASH_SIZE; x++)
1493 examine_bucket(examiner, sdp, x);
1494 }
1495
1496
1497 /**
1498 * thaw_glock - thaw out a glock which has an unprocessed reply waiting
1499 * @gl: The glock to thaw
1500 *
1501 */
1502
1503 static void thaw_glock(struct gfs2_glock *gl)
1504 {
1505 if (!test_and_clear_bit(GLF_FROZEN, &gl->gl_flags))
1506 goto out;
1507 set_bit(GLF_REPLY_PENDING, &gl->gl_flags);
1508 if (queue_delayed_work(glock_workqueue, &gl->gl_work, 0) == 0) {
1509 out:
1510 gfs2_glock_put(gl);
1511 }
1512 }
1513
1514 /**
1515 * clear_glock - look at a glock and see if we can free it from glock cache
1516 * @gl: the glock to look at
1517 *
1518 */
1519
1520 static void clear_glock(struct gfs2_glock *gl)
1521 {
1522 gfs2_glock_remove_from_lru(gl);
1523
1524 spin_lock(&gl->gl_spin);
1525 if (gl->gl_state != LM_ST_UNLOCKED)
1526 handle_callback(gl, LM_ST_UNLOCKED, 0, false);
1527 spin_unlock(&gl->gl_spin);
1528 if (queue_delayed_work(glock_workqueue, &gl->gl_work, 0) == 0)
1529 gfs2_glock_put(gl);
1530 }
1531
1532 /**
1533 * gfs2_glock_thaw - Thaw any frozen glocks
1534 * @sdp: The super block
1535 *
1536 */
1537
1538 void gfs2_glock_thaw(struct gfs2_sbd *sdp)
1539 {
1540 glock_hash_walk(thaw_glock, sdp);
1541 }
1542
1543 static void dump_glock(struct seq_file *seq, struct gfs2_glock *gl)
1544 {
1545 spin_lock(&gl->gl_spin);
1546 gfs2_dump_glock(seq, gl);
1547 spin_unlock(&gl->gl_spin);
1548 }
1549
1550 static void dump_glock_func(struct gfs2_glock *gl)
1551 {
1552 dump_glock(NULL, gl);
1553 }
1554
1555 /**
1556 * gfs2_gl_hash_clear - Empty out the glock hash table
1557 * @sdp: the filesystem
1558 * @wait: wait until it's all gone
1559 *
1560 * Called when unmounting the filesystem.
1561 */
1562
1563 void gfs2_gl_hash_clear(struct gfs2_sbd *sdp)
1564 {
1565 set_bit(SDF_SKIP_DLM_UNLOCK, &sdp->sd_flags);
1566 flush_workqueue(glock_workqueue);
1567 glock_hash_walk(clear_glock, sdp);
1568 flush_workqueue(glock_workqueue);
1569 wait_event(sdp->sd_glock_wait, atomic_read(&sdp->sd_glock_disposal) == 0);
1570 glock_hash_walk(dump_glock_func, sdp);
1571 }
1572
1573 void gfs2_glock_finish_truncate(struct gfs2_inode *ip)
1574 {
1575 struct gfs2_glock *gl = ip->i_gl;
1576 int ret;
1577
1578 ret = gfs2_truncatei_resume(ip);
1579 gfs2_assert_withdraw(gl->gl_sbd, ret == 0);
1580
1581 spin_lock(&gl->gl_spin);
1582 clear_bit(GLF_LOCK, &gl->gl_flags);
1583 run_queue(gl, 1);
1584 spin_unlock(&gl->gl_spin);
1585 }
1586
1587 static const char *state2str(unsigned state)
1588 {
1589 switch(state) {
1590 case LM_ST_UNLOCKED:
1591 return "UN";
1592 case LM_ST_SHARED:
1593 return "SH";
1594 case LM_ST_DEFERRED:
1595 return "DF";
1596 case LM_ST_EXCLUSIVE:
1597 return "EX";
1598 }
1599 return "??";
1600 }
1601
1602 static const char *hflags2str(char *buf, unsigned flags, unsigned long iflags)
1603 {
1604 char *p = buf;
1605 if (flags & LM_FLAG_TRY)
1606 *p++ = 't';
1607 if (flags & LM_FLAG_TRY_1CB)
1608 *p++ = 'T';
1609 if (flags & LM_FLAG_NOEXP)
1610 *p++ = 'e';
1611 if (flags & LM_FLAG_ANY)
1612 *p++ = 'A';
1613 if (flags & LM_FLAG_PRIORITY)
1614 *p++ = 'p';
1615 if (flags & GL_ASYNC)
1616 *p++ = 'a';
1617 if (flags & GL_EXACT)
1618 *p++ = 'E';
1619 if (flags & GL_NOCACHE)
1620 *p++ = 'c';
1621 if (test_bit(HIF_HOLDER, &iflags))
1622 *p++ = 'H';
1623 if (test_bit(HIF_WAIT, &iflags))
1624 *p++ = 'W';
1625 if (test_bit(HIF_FIRST, &iflags))
1626 *p++ = 'F';
1627 *p = 0;
1628 return buf;
1629 }
1630
1631 /**
1632 * dump_holder - print information about a glock holder
1633 * @seq: the seq_file struct
1634 * @gh: the glock holder
1635 *
1636 */
1637
1638 static void dump_holder(struct seq_file *seq, const struct gfs2_holder *gh)
1639 {
1640 struct task_struct *gh_owner = NULL;
1641 char flags_buf[32];
1642
1643 rcu_read_lock();
1644 if (gh->gh_owner_pid)
1645 gh_owner = pid_task(gh->gh_owner_pid, PIDTYPE_PID);
1646 gfs2_print_dbg(seq, " H: s:%s f:%s e:%d p:%ld [%s] %pS\n",
1647 state2str(gh->gh_state),
1648 hflags2str(flags_buf, gh->gh_flags, gh->gh_iflags),
1649 gh->gh_error,
1650 gh->gh_owner_pid ? (long)pid_nr(gh->gh_owner_pid) : -1,
1651 gh_owner ? gh_owner->comm : "(ended)",
1652 (void *)gh->gh_ip);
1653 rcu_read_unlock();
1654 }
1655
1656 static const char *gflags2str(char *buf, const struct gfs2_glock *gl)
1657 {
1658 const unsigned long *gflags = &gl->gl_flags;
1659 char *p = buf;
1660
1661 if (test_bit(GLF_LOCK, gflags))
1662 *p++ = 'l';
1663 if (test_bit(GLF_DEMOTE, gflags))
1664 *p++ = 'D';
1665 if (test_bit(GLF_PENDING_DEMOTE, gflags))
1666 *p++ = 'd';
1667 if (test_bit(GLF_DEMOTE_IN_PROGRESS, gflags))
1668 *p++ = 'p';
1669 if (test_bit(GLF_DIRTY, gflags))
1670 *p++ = 'y';
1671 if (test_bit(GLF_LFLUSH, gflags))
1672 *p++ = 'f';
1673 if (test_bit(GLF_INVALIDATE_IN_PROGRESS, gflags))
1674 *p++ = 'i';
1675 if (test_bit(GLF_REPLY_PENDING, gflags))
1676 *p++ = 'r';
1677 if (test_bit(GLF_INITIAL, gflags))
1678 *p++ = 'I';
1679 if (test_bit(GLF_FROZEN, gflags))
1680 *p++ = 'F';
1681 if (test_bit(GLF_QUEUED, gflags))
1682 *p++ = 'q';
1683 if (test_bit(GLF_LRU, gflags))
1684 *p++ = 'L';
1685 if (gl->gl_object)
1686 *p++ = 'o';
1687 if (test_bit(GLF_BLOCKING, gflags))
1688 *p++ = 'b';
1689 *p = 0;
1690 return buf;
1691 }
1692
1693 /**
1694 * gfs2_dump_glock - print information about a glock
1695 * @seq: The seq_file struct
1696 * @gl: the glock
1697 *
1698 * The file format is as follows:
1699 * One line per object, capital letters are used to indicate objects
1700 * G = glock, I = Inode, R = rgrp, H = holder. Glocks are not indented,
1701 * other objects are indented by a single space and follow the glock to
1702 * which they are related. Fields are indicated by lower case letters
1703 * followed by a colon and the field value, except for strings which are in
1704 * [] so that its possible to see if they are composed of spaces for
1705 * example. The field's are n = number (id of the object), f = flags,
1706 * t = type, s = state, r = refcount, e = error, p = pid.
1707 *
1708 */
1709
1710 void gfs2_dump_glock(struct seq_file *seq, const struct gfs2_glock *gl)
1711 {
1712 const struct gfs2_glock_operations *glops = gl->gl_ops;
1713 unsigned long long dtime;
1714 const struct gfs2_holder *gh;
1715 char gflags_buf[32];
1716
1717 dtime = jiffies - gl->gl_demote_time;
1718 dtime *= 1000000/HZ; /* demote time in uSec */
1719 if (!test_bit(GLF_DEMOTE, &gl->gl_flags))
1720 dtime = 0;
1721 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",
1722 state2str(gl->gl_state),
1723 gl->gl_name.ln_type,
1724 (unsigned long long)gl->gl_name.ln_number,
1725 gflags2str(gflags_buf, gl),
1726 state2str(gl->gl_target),
1727 state2str(gl->gl_demote_state), dtime,
1728 atomic_read(&gl->gl_ail_count),
1729 atomic_read(&gl->gl_revokes),
1730 (int)gl->gl_lockref.count, gl->gl_hold_time);
1731
1732 list_for_each_entry(gh, &gl->gl_holders, gh_list)
1733 dump_holder(seq, gh);
1734
1735 if (gl->gl_state != LM_ST_UNLOCKED && glops->go_dump)
1736 glops->go_dump(seq, gl);
1737 }
1738
1739 static int gfs2_glstats_seq_show(struct seq_file *seq, void *iter_ptr)
1740 {
1741 struct gfs2_glock *gl = iter_ptr;
1742
1743 seq_printf(seq, "G: n:%u/%llx rtt:%lld/%lld rttb:%lld/%lld irt:%lld/%lld dcnt: %lld qcnt: %lld\n",
1744 gl->gl_name.ln_type,
1745 (unsigned long long)gl->gl_name.ln_number,
1746 (long long)gl->gl_stats.stats[GFS2_LKS_SRTT],
1747 (long long)gl->gl_stats.stats[GFS2_LKS_SRTTVAR],
1748 (long long)gl->gl_stats.stats[GFS2_LKS_SRTTB],
1749 (long long)gl->gl_stats.stats[GFS2_LKS_SRTTVARB],
1750 (long long)gl->gl_stats.stats[GFS2_LKS_SIRT],
1751 (long long)gl->gl_stats.stats[GFS2_LKS_SIRTVAR],
1752 (long long)gl->gl_stats.stats[GFS2_LKS_DCOUNT],
1753 (long long)gl->gl_stats.stats[GFS2_LKS_QCOUNT]);
1754 return 0;
1755 }
1756
1757 static const char *gfs2_gltype[] = {
1758 "type",
1759 "reserved",
1760 "nondisk",
1761 "inode",
1762 "rgrp",
1763 "meta",
1764 "iopen",
1765 "flock",
1766 "plock",
1767 "quota",
1768 "journal",
1769 };
1770
1771 static const char *gfs2_stype[] = {
1772 [GFS2_LKS_SRTT] = "srtt",
1773 [GFS2_LKS_SRTTVAR] = "srttvar",
1774 [GFS2_LKS_SRTTB] = "srttb",
1775 [GFS2_LKS_SRTTVARB] = "srttvarb",
1776 [GFS2_LKS_SIRT] = "sirt",
1777 [GFS2_LKS_SIRTVAR] = "sirtvar",
1778 [GFS2_LKS_DCOUNT] = "dlm",
1779 [GFS2_LKS_QCOUNT] = "queue",
1780 };
1781
1782 #define GFS2_NR_SBSTATS (ARRAY_SIZE(gfs2_gltype) * ARRAY_SIZE(gfs2_stype))
1783
1784 static int gfs2_sbstats_seq_show(struct seq_file *seq, void *iter_ptr)
1785 {
1786 struct gfs2_glock_iter *gi = seq->private;
1787 struct gfs2_sbd *sdp = gi->sdp;
1788 unsigned index = gi->hash >> 3;
1789 unsigned subindex = gi->hash & 0x07;
1790 s64 value;
1791 int i;
1792
1793 if (index == 0 && subindex != 0)
1794 return 0;
1795
1796 seq_printf(seq, "%-10s %8s:", gfs2_gltype[index],
1797 (index == 0) ? "cpu": gfs2_stype[subindex]);
1798
1799 for_each_possible_cpu(i) {
1800 const struct gfs2_pcpu_lkstats *lkstats = per_cpu_ptr(sdp->sd_lkstats, i);
1801 if (index == 0) {
1802 value = i;
1803 } else {
1804 value = lkstats->lkstats[index - 1].stats[subindex];
1805 }
1806 seq_printf(seq, " %15lld", (long long)value);
1807 }
1808 seq_putc(seq, '\n');
1809 return 0;
1810 }
1811
1812 int __init gfs2_glock_init(void)
1813 {
1814 unsigned i;
1815 for(i = 0; i < GFS2_GL_HASH_SIZE; i++) {
1816 INIT_HLIST_BL_HEAD(&gl_hash_table[i]);
1817 }
1818
1819 glock_workqueue = alloc_workqueue("glock_workqueue", WQ_MEM_RECLAIM |
1820 WQ_HIGHPRI | WQ_FREEZABLE, 0);
1821 if (!glock_workqueue)
1822 return -ENOMEM;
1823 gfs2_delete_workqueue = alloc_workqueue("delete_workqueue",
1824 WQ_MEM_RECLAIM | WQ_FREEZABLE,
1825 0);
1826 if (!gfs2_delete_workqueue) {
1827 destroy_workqueue(glock_workqueue);
1828 return -ENOMEM;
1829 }
1830
1831 register_shrinker(&glock_shrinker);
1832
1833 return 0;
1834 }
1835
1836 void gfs2_glock_exit(void)
1837 {
1838 unregister_shrinker(&glock_shrinker);
1839 destroy_workqueue(glock_workqueue);
1840 destroy_workqueue(gfs2_delete_workqueue);
1841 }
1842
1843 static inline struct gfs2_glock *glock_hash_chain(unsigned hash)
1844 {
1845 return hlist_bl_entry(hlist_bl_first_rcu(&gl_hash_table[hash]),
1846 struct gfs2_glock, gl_list);
1847 }
1848
1849 static inline struct gfs2_glock *glock_hash_next(struct gfs2_glock *gl)
1850 {
1851 return hlist_bl_entry(rcu_dereference(gl->gl_list.next),
1852 struct gfs2_glock, gl_list);
1853 }
1854
1855 static int gfs2_glock_iter_next(struct gfs2_glock_iter *gi)
1856 {
1857 struct gfs2_glock *gl;
1858
1859 do {
1860 gl = gi->gl;
1861 if (gl) {
1862 gi->gl = glock_hash_next(gl);
1863 gi->nhash++;
1864 } else {
1865 if (gi->hash >= GFS2_GL_HASH_SIZE) {
1866 rcu_read_unlock();
1867 return 1;
1868 }
1869 gi->gl = glock_hash_chain(gi->hash);
1870 gi->nhash = 0;
1871 }
1872 while (gi->gl == NULL) {
1873 gi->hash++;
1874 if (gi->hash >= GFS2_GL_HASH_SIZE) {
1875 rcu_read_unlock();
1876 return 1;
1877 }
1878 gi->gl = glock_hash_chain(gi->hash);
1879 gi->nhash = 0;
1880 }
1881 /* Skip entries for other sb and dead entries */
1882 } while (gi->sdp != gi->gl->gl_sbd ||
1883 __lockref_is_dead(&gi->gl->gl_lockref));
1884
1885 return 0;
1886 }
1887
1888 static void *gfs2_glock_seq_start(struct seq_file *seq, loff_t *pos)
1889 {
1890 struct gfs2_glock_iter *gi = seq->private;
1891 loff_t n = *pos;
1892
1893 if (gi->last_pos <= *pos)
1894 n = gi->nhash + (*pos - gi->last_pos);
1895 else
1896 gi->hash = 0;
1897
1898 gi->nhash = 0;
1899 rcu_read_lock();
1900
1901 do {
1902 if (gfs2_glock_iter_next(gi))
1903 return NULL;
1904 } while (n--);
1905
1906 gi->last_pos = *pos;
1907 return gi->gl;
1908 }
1909
1910 static void *gfs2_glock_seq_next(struct seq_file *seq, void *iter_ptr,
1911 loff_t *pos)
1912 {
1913 struct gfs2_glock_iter *gi = seq->private;
1914
1915 (*pos)++;
1916 gi->last_pos = *pos;
1917 if (gfs2_glock_iter_next(gi))
1918 return NULL;
1919
1920 return gi->gl;
1921 }
1922
1923 static void gfs2_glock_seq_stop(struct seq_file *seq, void *iter_ptr)
1924 {
1925 struct gfs2_glock_iter *gi = seq->private;
1926
1927 if (gi->gl)
1928 rcu_read_unlock();
1929 gi->gl = NULL;
1930 }
1931
1932 static int gfs2_glock_seq_show(struct seq_file *seq, void *iter_ptr)
1933 {
1934 dump_glock(seq, iter_ptr);
1935 return 0;
1936 }
1937
1938 static void *gfs2_sbstats_seq_start(struct seq_file *seq, loff_t *pos)
1939 {
1940 struct gfs2_glock_iter *gi = seq->private;
1941
1942 gi->hash = *pos;
1943 if (*pos >= GFS2_NR_SBSTATS)
1944 return NULL;
1945 preempt_disable();
1946 return SEQ_START_TOKEN;
1947 }
1948
1949 static void *gfs2_sbstats_seq_next(struct seq_file *seq, void *iter_ptr,
1950 loff_t *pos)
1951 {
1952 struct gfs2_glock_iter *gi = seq->private;
1953 (*pos)++;
1954 gi->hash++;
1955 if (gi->hash >= GFS2_NR_SBSTATS) {
1956 preempt_enable();
1957 return NULL;
1958 }
1959 return SEQ_START_TOKEN;
1960 }
1961
1962 static void gfs2_sbstats_seq_stop(struct seq_file *seq, void *iter_ptr)
1963 {
1964 preempt_enable();
1965 }
1966
1967 static const struct seq_operations gfs2_glock_seq_ops = {
1968 .start = gfs2_glock_seq_start,
1969 .next = gfs2_glock_seq_next,
1970 .stop = gfs2_glock_seq_stop,
1971 .show = gfs2_glock_seq_show,
1972 };
1973
1974 static const struct seq_operations gfs2_glstats_seq_ops = {
1975 .start = gfs2_glock_seq_start,
1976 .next = gfs2_glock_seq_next,
1977 .stop = gfs2_glock_seq_stop,
1978 .show = gfs2_glstats_seq_show,
1979 };
1980
1981 static const struct seq_operations gfs2_sbstats_seq_ops = {
1982 .start = gfs2_sbstats_seq_start,
1983 .next = gfs2_sbstats_seq_next,
1984 .stop = gfs2_sbstats_seq_stop,
1985 .show = gfs2_sbstats_seq_show,
1986 };
1987
1988 #define GFS2_SEQ_GOODSIZE min(PAGE_SIZE << PAGE_ALLOC_COSTLY_ORDER, 65536UL)
1989
1990 static int gfs2_glocks_open(struct inode *inode, struct file *file)
1991 {
1992 int ret = seq_open_private(file, &gfs2_glock_seq_ops,
1993 sizeof(struct gfs2_glock_iter));
1994 if (ret == 0) {
1995 struct seq_file *seq = file->private_data;
1996 struct gfs2_glock_iter *gi = seq->private;
1997 gi->sdp = inode->i_private;
1998 seq->buf = kmalloc(GFS2_SEQ_GOODSIZE, GFP_KERNEL | __GFP_NOWARN);
1999 if (seq->buf)
2000 seq->size = GFS2_SEQ_GOODSIZE;
2001 }
2002 return ret;
2003 }
2004
2005 static int gfs2_glstats_open(struct inode *inode, struct file *file)
2006 {
2007 int ret = seq_open_private(file, &gfs2_glstats_seq_ops,
2008 sizeof(struct gfs2_glock_iter));
2009 if (ret == 0) {
2010 struct seq_file *seq = file->private_data;
2011 struct gfs2_glock_iter *gi = seq->private;
2012 gi->sdp = inode->i_private;
2013 seq->buf = kmalloc(GFS2_SEQ_GOODSIZE, GFP_KERNEL | __GFP_NOWARN);
2014 if (seq->buf)
2015 seq->size = GFS2_SEQ_GOODSIZE;
2016 }
2017 return ret;
2018 }
2019
2020 static int gfs2_sbstats_open(struct inode *inode, struct file *file)
2021 {
2022 int ret = seq_open_private(file, &gfs2_sbstats_seq_ops,
2023 sizeof(struct gfs2_glock_iter));
2024 if (ret == 0) {
2025 struct seq_file *seq = file->private_data;
2026 struct gfs2_glock_iter *gi = seq->private;
2027 gi->sdp = inode->i_private;
2028 }
2029 return ret;
2030 }
2031
2032 static const struct file_operations gfs2_glocks_fops = {
2033 .owner = THIS_MODULE,
2034 .open = gfs2_glocks_open,
2035 .read = seq_read,
2036 .llseek = seq_lseek,
2037 .release = seq_release_private,
2038 };
2039
2040 static const struct file_operations gfs2_glstats_fops = {
2041 .owner = THIS_MODULE,
2042 .open = gfs2_glstats_open,
2043 .read = seq_read,
2044 .llseek = seq_lseek,
2045 .release = seq_release_private,
2046 };
2047
2048 static const struct file_operations gfs2_sbstats_fops = {
2049 .owner = THIS_MODULE,
2050 .open = gfs2_sbstats_open,
2051 .read = seq_read,
2052 .llseek = seq_lseek,
2053 .release = seq_release_private,
2054 };
2055
2056 int gfs2_create_debugfs_file(struct gfs2_sbd *sdp)
2057 {
2058 sdp->debugfs_dir = debugfs_create_dir(sdp->sd_table_name, gfs2_root);
2059 if (!sdp->debugfs_dir)
2060 return -ENOMEM;
2061 sdp->debugfs_dentry_glocks = debugfs_create_file("glocks",
2062 S_IFREG | S_IRUGO,
2063 sdp->debugfs_dir, sdp,
2064 &gfs2_glocks_fops);
2065 if (!sdp->debugfs_dentry_glocks)
2066 goto fail;
2067
2068 sdp->debugfs_dentry_glstats = debugfs_create_file("glstats",
2069 S_IFREG | S_IRUGO,
2070 sdp->debugfs_dir, sdp,
2071 &gfs2_glstats_fops);
2072 if (!sdp->debugfs_dentry_glstats)
2073 goto fail;
2074
2075 sdp->debugfs_dentry_sbstats = debugfs_create_file("sbstats",
2076 S_IFREG | S_IRUGO,
2077 sdp->debugfs_dir, sdp,
2078 &gfs2_sbstats_fops);
2079 if (!sdp->debugfs_dentry_sbstats)
2080 goto fail;
2081
2082 return 0;
2083 fail:
2084 gfs2_delete_debugfs_file(sdp);
2085 return -ENOMEM;
2086 }
2087
2088 void gfs2_delete_debugfs_file(struct gfs2_sbd *sdp)
2089 {
2090 if (sdp->debugfs_dir) {
2091 if (sdp->debugfs_dentry_glocks) {
2092 debugfs_remove(sdp->debugfs_dentry_glocks);
2093 sdp->debugfs_dentry_glocks = NULL;
2094 }
2095 if (sdp->debugfs_dentry_glstats) {
2096 debugfs_remove(sdp->debugfs_dentry_glstats);
2097 sdp->debugfs_dentry_glstats = NULL;
2098 }
2099 if (sdp->debugfs_dentry_sbstats) {
2100 debugfs_remove(sdp->debugfs_dentry_sbstats);
2101 sdp->debugfs_dentry_sbstats = NULL;
2102 }
2103 debugfs_remove(sdp->debugfs_dir);
2104 sdp->debugfs_dir = NULL;
2105 }
2106 }
2107
2108 int gfs2_register_debugfs(void)
2109 {
2110 gfs2_root = debugfs_create_dir("gfs2", NULL);
2111 return gfs2_root ? 0 : -ENOMEM;
2112 }
2113
2114 void gfs2_unregister_debugfs(void)
2115 {
2116 debugfs_remove(gfs2_root);
2117 gfs2_root = NULL;
2118 }
Linux with added FPC-III support