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ping: implement proper locking
[linux/fpc-iii.git] / fs / gfs2 / glock.c
blob133f322573b5ffb26dfdcb13502d09164bbae708
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 #include <linux/rhashtable.h>
38
39 #include "gfs2.h"
40 #include "incore.h"
41 #include "glock.h"
42 #include "glops.h"
43 #include "inode.h"
44 #include "lops.h"
45 #include "meta_io.h"
46 #include "quota.h"
47 #include "super.h"
48 #include "util.h"
49 #include "bmap.h"
50 #define CREATE_TRACE_POINTS
51 #include "trace_gfs2.h"
52
53 struct gfs2_glock_iter {
54 struct gfs2_sbd *sdp; /* incore superblock */
55 struct rhashtable_iter hti; /* rhashtable iterator */
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 BIT(GFS2_GL_HASH_SHIFT)
73
74 static struct rhashtable_params ht_parms = {
75 .nelem_hint = GFS2_GL_HASH_SIZE * 3 / 4,
76 .key_len = sizeof(struct lm_lockname),
77 .key_offset = offsetof(struct gfs2_glock, gl_name),
78 .head_offset = offsetof(struct gfs2_glock, gl_node),
79 };
80
81 static struct rhashtable gl_hash_table;
82
83 void gfs2_glock_free(struct gfs2_glock *gl)
84 {
85 struct gfs2_sbd *sdp = gl->gl_name.ln_sbd;
86
87 if (gl->gl_ops->go_flags & GLOF_ASPACE) {
88 kmem_cache_free(gfs2_glock_aspace_cachep, gl);
89 } else {
90 kfree(gl->gl_lksb.sb_lvbptr);
91 kmem_cache_free(gfs2_glock_cachep, gl);
92 }
93 if (atomic_dec_and_test(&sdp->sd_glock_disposal))
94 wake_up(&sdp->sd_glock_wait);
95 }
96
97 /**
98 * gfs2_glock_hold() - increment reference count on glock
99 * @gl: The glock to hold
100 *
101 */
102
103 static void gfs2_glock_hold(struct gfs2_glock *gl)
104 {
105 GLOCK_BUG_ON(gl, __lockref_is_dead(&gl->gl_lockref));
106 lockref_get(&gl->gl_lockref);
107 }
108
109 /**
110 * demote_ok - Check to see if it's ok to unlock a glock
111 * @gl: the glock
112 *
113 * Returns: 1 if it's ok
114 */
115
116 static int demote_ok(const struct gfs2_glock *gl)
117 {
118 const struct gfs2_glock_operations *glops = gl->gl_ops;
119
120 if (gl->gl_state == LM_ST_UNLOCKED)
121 return 0;
122 if (!list_empty(&gl->gl_holders))
123 return 0;
124 if (glops->go_demote_ok)
125 return glops->go_demote_ok(gl);
126 return 1;
127 }
128
129
130 void gfs2_glock_add_to_lru(struct gfs2_glock *gl)
131 {
132 spin_lock(&lru_lock);
133
134 if (!list_empty(&gl->gl_lru))
135 list_del_init(&gl->gl_lru);
136 else
137 atomic_inc(&lru_count);
138
139 list_add_tail(&gl->gl_lru, &lru_list);
140 set_bit(GLF_LRU, &gl->gl_flags);
141 spin_unlock(&lru_lock);
142 }
143
144 static void gfs2_glock_remove_from_lru(struct gfs2_glock *gl)
145 {
146 spin_lock(&lru_lock);
147 if (!list_empty(&gl->gl_lru)) {
148 list_del_init(&gl->gl_lru);
149 atomic_dec(&lru_count);
150 clear_bit(GLF_LRU, &gl->gl_flags);
151 }
152 spin_unlock(&lru_lock);
153 }
154
155 /**
156 * gfs2_glock_put() - Decrement reference count on glock
157 * @gl: The glock to put
158 *
159 */
160
161 void gfs2_glock_put(struct gfs2_glock *gl)
162 {
163 struct gfs2_sbd *sdp = gl->gl_name.ln_sbd;
164 struct address_space *mapping = gfs2_glock2aspace(gl);
165
166 if (lockref_put_or_lock(&gl->gl_lockref))
167 return;
168
169 lockref_mark_dead(&gl->gl_lockref);
170
171 gfs2_glock_remove_from_lru(gl);
172 spin_unlock(&gl->gl_lockref.lock);
173 rhashtable_remove_fast(&gl_hash_table, &gl->gl_node, ht_parms);
174 GLOCK_BUG_ON(gl, !list_empty(&gl->gl_holders));
175 GLOCK_BUG_ON(gl, mapping && mapping->nrpages);
176 trace_gfs2_glock_put(gl);
177 sdp->sd_lockstruct.ls_ops->lm_put_lock(gl);
178 }
179
180 /**
181 * may_grant - check if its ok to grant a new lock
182 * @gl: The glock
183 * @gh: The lock request which we wish to grant
184 *
185 * Returns: true if its ok to grant the lock
186 */
187
188 static inline int may_grant(const struct gfs2_glock *gl, const struct gfs2_holder *gh)
189 {
190 const struct gfs2_holder *gh_head = list_entry(gl->gl_holders.next, const struct gfs2_holder, gh_list);
191 if ((gh->gh_state == LM_ST_EXCLUSIVE ||
192 gh_head->gh_state == LM_ST_EXCLUSIVE) && gh != gh_head)
193 return 0;
194 if (gl->gl_state == gh->gh_state)
195 return 1;
196 if (gh->gh_flags & GL_EXACT)
197 return 0;
198 if (gl->gl_state == LM_ST_EXCLUSIVE) {
199 if (gh->gh_state == LM_ST_SHARED && gh_head->gh_state == LM_ST_SHARED)
200 return 1;
201 if (gh->gh_state == LM_ST_DEFERRED && gh_head->gh_state == LM_ST_DEFERRED)
202 return 1;
203 }
204 if (gl->gl_state != LM_ST_UNLOCKED && (gh->gh_flags & LM_FLAG_ANY))
205 return 1;
206 return 0;
207 }
208
209 static void gfs2_holder_wake(struct gfs2_holder *gh)
210 {
211 clear_bit(HIF_WAIT, &gh->gh_iflags);
212 smp_mb__after_atomic();
213 wake_up_bit(&gh->gh_iflags, HIF_WAIT);
214 }
215
216 /**
217 * do_error - Something unexpected has happened during a lock request
218 *
219 */
220
221 static void do_error(struct gfs2_glock *gl, const int ret)
222 {
223 struct gfs2_holder *gh, *tmp;
224
225 list_for_each_entry_safe(gh, tmp, &gl->gl_holders, gh_list) {
226 if (test_bit(HIF_HOLDER, &gh->gh_iflags))
227 continue;
228 if (ret & LM_OUT_ERROR)
229 gh->gh_error = -EIO;
230 else if (gh->gh_flags & (LM_FLAG_TRY | LM_FLAG_TRY_1CB))
231 gh->gh_error = GLR_TRYFAILED;
232 else
233 continue;
234 list_del_init(&gh->gh_list);
235 trace_gfs2_glock_queue(gh, 0);
236 gfs2_holder_wake(gh);
237 }
238 }
239
240 /**
241 * do_promote - promote as many requests as possible on the current queue
242 * @gl: The glock
243 *
244 * Returns: 1 if there is a blocked holder at the head of the list, or 2
245 * if a type specific operation is underway.
246 */
247
248 static int do_promote(struct gfs2_glock *gl)
249 __releases(&gl->gl_lockref.lock)
250 __acquires(&gl->gl_lockref.lock)
251 {
252 const struct gfs2_glock_operations *glops = gl->gl_ops;
253 struct gfs2_holder *gh, *tmp;
254 int ret;
255
256 restart:
257 list_for_each_entry_safe(gh, tmp, &gl->gl_holders, gh_list) {
258 if (test_bit(HIF_HOLDER, &gh->gh_iflags))
259 continue;
260 if (may_grant(gl, gh)) {
261 if (gh->gh_list.prev == &gl->gl_holders &&
262 glops->go_lock) {
263 spin_unlock(&gl->gl_lockref.lock);
264 /* FIXME: eliminate this eventually */
265 ret = glops->go_lock(gh);
266 spin_lock(&gl->gl_lockref.lock);
267 if (ret) {
268 if (ret == 1)
269 return 2;
270 gh->gh_error = ret;
271 list_del_init(&gh->gh_list);
272 trace_gfs2_glock_queue(gh, 0);
273 gfs2_holder_wake(gh);
274 goto restart;
275 }
276 set_bit(HIF_HOLDER, &gh->gh_iflags);
277 trace_gfs2_promote(gh, 1);
278 gfs2_holder_wake(gh);
279 goto restart;
280 }
281 set_bit(HIF_HOLDER, &gh->gh_iflags);
282 trace_gfs2_promote(gh, 0);
283 gfs2_holder_wake(gh);
284 continue;
285 }
286 if (gh->gh_list.prev == &gl->gl_holders)
287 return 1;
288 do_error(gl, 0);
289 break;
290 }
291 return 0;
292 }
293
294 /**
295 * find_first_waiter - find the first gh that's waiting for the glock
296 * @gl: the glock
297 */
298
299 static inline struct gfs2_holder *find_first_waiter(const struct gfs2_glock *gl)
300 {
301 struct gfs2_holder *gh;
302
303 list_for_each_entry(gh, &gl->gl_holders, gh_list) {
304 if (!test_bit(HIF_HOLDER, &gh->gh_iflags))
305 return gh;
306 }
307 return NULL;
308 }
309
310 /**
311 * state_change - record that the glock is now in a different state
312 * @gl: the glock
313 * @new_state the new state
314 *
315 */
316
317 static void state_change(struct gfs2_glock *gl, unsigned int new_state)
318 {
319 int held1, held2;
320
321 held1 = (gl->gl_state != LM_ST_UNLOCKED);
322 held2 = (new_state != LM_ST_UNLOCKED);
323
324 if (held1 != held2) {
325 GLOCK_BUG_ON(gl, __lockref_is_dead(&gl->gl_lockref));
326 if (held2)
327 gl->gl_lockref.count++;
328 else
329 gl->gl_lockref.count--;
330 }
331 if (held1 && held2 && list_empty(&gl->gl_holders))
332 clear_bit(GLF_QUEUED, &gl->gl_flags);
333
334 if (new_state != gl->gl_target)
335 /* shorten our minimum hold time */
336 gl->gl_hold_time = max(gl->gl_hold_time - GL_GLOCK_HOLD_DECR,
337 GL_GLOCK_MIN_HOLD);
338 gl->gl_state = new_state;
339 gl->gl_tchange = jiffies;
340 }
341
342 static void gfs2_demote_wake(struct gfs2_glock *gl)
343 {
344 gl->gl_demote_state = LM_ST_EXCLUSIVE;
345 clear_bit(GLF_DEMOTE, &gl->gl_flags);
346 smp_mb__after_atomic();
347 wake_up_bit(&gl->gl_flags, GLF_DEMOTE);
348 }
349
350 /**
351 * finish_xmote - The DLM has replied to one of our lock requests
352 * @gl: The glock
353 * @ret: The status from the DLM
354 *
355 */
356
357 static void finish_xmote(struct gfs2_glock *gl, unsigned int ret)
358 {
359 const struct gfs2_glock_operations *glops = gl->gl_ops;
360 struct gfs2_holder *gh;
361 unsigned state = ret & LM_OUT_ST_MASK;
362 int rv;
363
364 spin_lock(&gl->gl_lockref.lock);
365 trace_gfs2_glock_state_change(gl, state);
366 state_change(gl, state);
367 gh = find_first_waiter(gl);
368
369 /* Demote to UN request arrived during demote to SH or DF */
370 if (test_bit(GLF_DEMOTE_IN_PROGRESS, &gl->gl_flags) &&
371 state != LM_ST_UNLOCKED && gl->gl_demote_state == LM_ST_UNLOCKED)
372 gl->gl_target = LM_ST_UNLOCKED;
373
374 /* Check for state != intended state */
375 if (unlikely(state != gl->gl_target)) {
376 if (gh && !test_bit(GLF_DEMOTE_IN_PROGRESS, &gl->gl_flags)) {
377 /* move to back of queue and try next entry */
378 if (ret & LM_OUT_CANCELED) {
379 if ((gh->gh_flags & LM_FLAG_PRIORITY) == 0)
380 list_move_tail(&gh->gh_list, &gl->gl_holders);
381 gh = find_first_waiter(gl);
382 gl->gl_target = gh->gh_state;
383 goto retry;
384 }
385 /* Some error or failed "try lock" - report it */
386 if ((ret & LM_OUT_ERROR) ||
387 (gh->gh_flags & (LM_FLAG_TRY | LM_FLAG_TRY_1CB))) {
388 gl->gl_target = gl->gl_state;
389 do_error(gl, ret);
390 goto out;
391 }
392 }
393 switch(state) {
394 /* Unlocked due to conversion deadlock, try again */
395 case LM_ST_UNLOCKED:
396 retry:
397 do_xmote(gl, gh, gl->gl_target);
398 break;
399 /* Conversion fails, unlock and try again */
400 case LM_ST_SHARED:
401 case LM_ST_DEFERRED:
402 do_xmote(gl, gh, LM_ST_UNLOCKED);
403 break;
404 default: /* Everything else */
405 pr_err("wanted %u got %u\n", gl->gl_target, state);
406 GLOCK_BUG_ON(gl, 1);
407 }
408 spin_unlock(&gl->gl_lockref.lock);
409 return;
410 }
411
412 /* Fast path - we got what we asked for */
413 if (test_and_clear_bit(GLF_DEMOTE_IN_PROGRESS, &gl->gl_flags))
414 gfs2_demote_wake(gl);
415 if (state != LM_ST_UNLOCKED) {
416 if (glops->go_xmote_bh) {
417 spin_unlock(&gl->gl_lockref.lock);
418 rv = glops->go_xmote_bh(gl, gh);
419 spin_lock(&gl->gl_lockref.lock);
420 if (rv) {
421 do_error(gl, rv);
422 goto out;
423 }
424 }
425 rv = do_promote(gl);
426 if (rv == 2)
427 goto out_locked;
428 }
429 out:
430 clear_bit(GLF_LOCK, &gl->gl_flags);
431 out_locked:
432 spin_unlock(&gl->gl_lockref.lock);
433 }
434
435 /**
436 * do_xmote - Calls the DLM to change the state of a lock
437 * @gl: The lock state
438 * @gh: The holder (only for promotes)
439 * @target: The target lock state
440 *
441 */
442
443 static void do_xmote(struct gfs2_glock *gl, struct gfs2_holder *gh, unsigned int target)
444 __releases(&gl->gl_lockref.lock)
445 __acquires(&gl->gl_lockref.lock)
446 {
447 const struct gfs2_glock_operations *glops = gl->gl_ops;
448 struct gfs2_sbd *sdp = gl->gl_name.ln_sbd;
449 unsigned int lck_flags = (unsigned int)(gh ? gh->gh_flags : 0);
450 int ret;
451
452 lck_flags &= (LM_FLAG_TRY | LM_FLAG_TRY_1CB | LM_FLAG_NOEXP |
453 LM_FLAG_PRIORITY);
454 GLOCK_BUG_ON(gl, gl->gl_state == target);
455 GLOCK_BUG_ON(gl, gl->gl_state == gl->gl_target);
456 if ((target == LM_ST_UNLOCKED || target == LM_ST_DEFERRED) &&
457 glops->go_inval) {
458 set_bit(GLF_INVALIDATE_IN_PROGRESS, &gl->gl_flags);
459 do_error(gl, 0); /* Fail queued try locks */
460 }
461 gl->gl_req = target;
462 set_bit(GLF_BLOCKING, &gl->gl_flags);
463 if ((gl->gl_req == LM_ST_UNLOCKED) ||
464 (gl->gl_state == LM_ST_EXCLUSIVE) ||
465 (lck_flags & (LM_FLAG_TRY|LM_FLAG_TRY_1CB)))
466 clear_bit(GLF_BLOCKING, &gl->gl_flags);
467 spin_unlock(&gl->gl_lockref.lock);
468 if (glops->go_sync)
469 glops->go_sync(gl);
470 if (test_bit(GLF_INVALIDATE_IN_PROGRESS, &gl->gl_flags))
471 glops->go_inval(gl, target == LM_ST_DEFERRED ? 0 : DIO_METADATA);
472 clear_bit(GLF_INVALIDATE_IN_PROGRESS, &gl->gl_flags);
473
474 gfs2_glock_hold(gl);
475 if (sdp->sd_lockstruct.ls_ops->lm_lock) {
476 /* lock_dlm */
477 ret = sdp->sd_lockstruct.ls_ops->lm_lock(gl, target, lck_flags);
478 if (ret == -EINVAL && gl->gl_target == LM_ST_UNLOCKED &&
479 target == LM_ST_UNLOCKED &&
480 test_bit(SDF_SKIP_DLM_UNLOCK, &sdp->sd_flags)) {
481 finish_xmote(gl, target);
482 if (queue_delayed_work(glock_workqueue, &gl->gl_work, 0) == 0)
483 gfs2_glock_put(gl);
484 }
485 else if (ret) {
486 pr_err("lm_lock ret %d\n", ret);
487 GLOCK_BUG_ON(gl, 1);
488 }
489 } else { /* lock_nolock */
490 finish_xmote(gl, target);
491 if (queue_delayed_work(glock_workqueue, &gl->gl_work, 0) == 0)
492 gfs2_glock_put(gl);
493 }
494
495 spin_lock(&gl->gl_lockref.lock);
496 }
497
498 /**
499 * find_first_holder - find the first "holder" gh
500 * @gl: the glock
501 */
502
503 static inline struct gfs2_holder *find_first_holder(const struct gfs2_glock *gl)
504 {
505 struct gfs2_holder *gh;
506
507 if (!list_empty(&gl->gl_holders)) {
508 gh = list_entry(gl->gl_holders.next, struct gfs2_holder, gh_list);
509 if (test_bit(HIF_HOLDER, &gh->gh_iflags))
510 return gh;
511 }
512 return NULL;
513 }
514
515 /**
516 * run_queue - do all outstanding tasks related to a glock
517 * @gl: The glock in question
518 * @nonblock: True if we must not block in run_queue
519 *
520 */
521
522 static void run_queue(struct gfs2_glock *gl, const int nonblock)
523 __releases(&gl->gl_lockref.lock)
524 __acquires(&gl->gl_lockref.lock)
525 {
526 struct gfs2_holder *gh = NULL;
527 int ret;
528
529 if (test_and_set_bit(GLF_LOCK, &gl->gl_flags))
530 return;
531
532 GLOCK_BUG_ON(gl, test_bit(GLF_DEMOTE_IN_PROGRESS, &gl->gl_flags));
533
534 if (test_bit(GLF_DEMOTE, &gl->gl_flags) &&
535 gl->gl_demote_state != gl->gl_state) {
536 if (find_first_holder(gl))
537 goto out_unlock;
538 if (nonblock)
539 goto out_sched;
540 set_bit(GLF_DEMOTE_IN_PROGRESS, &gl->gl_flags);
541 GLOCK_BUG_ON(gl, gl->gl_demote_state == LM_ST_EXCLUSIVE);
542 gl->gl_target = gl->gl_demote_state;
543 } else {
544 if (test_bit(GLF_DEMOTE, &gl->gl_flags))
545 gfs2_demote_wake(gl);
546 ret = do_promote(gl);
547 if (ret == 0)
548 goto out_unlock;
549 if (ret == 2)
550 goto out;
551 gh = find_first_waiter(gl);
552 gl->gl_target = gh->gh_state;
553 if (!(gh->gh_flags & (LM_FLAG_TRY | LM_FLAG_TRY_1CB)))
554 do_error(gl, 0); /* Fail queued try locks */
555 }
556 do_xmote(gl, gh, gl->gl_target);
557 out:
558 return;
559
560 out_sched:
561 clear_bit(GLF_LOCK, &gl->gl_flags);
562 smp_mb__after_atomic();
563 gl->gl_lockref.count++;
564 if (queue_delayed_work(glock_workqueue, &gl->gl_work, 0) == 0)
565 gl->gl_lockref.count--;
566 return;
567
568 out_unlock:
569 clear_bit(GLF_LOCK, &gl->gl_flags);
570 smp_mb__after_atomic();
571 return;
572 }
573
574 static void delete_work_func(struct work_struct *work)
575 {
576 struct gfs2_glock *gl = container_of(work, struct gfs2_glock, gl_delete);
577 struct gfs2_sbd *sdp = gl->gl_name.ln_sbd;
578 struct inode *inode;
579 u64 no_addr = gl->gl_name.ln_number;
580
581 /* If someone's using this glock to create a new dinode, the block must
582 have been freed by another node, then re-used, in which case our
583 iopen callback is too late after the fact. Ignore it. */
584 if (test_bit(GLF_INODE_CREATING, &gl->gl_flags))
585 goto out;
586
587 inode = gfs2_lookup_by_inum(sdp, no_addr, NULL, GFS2_BLKST_UNLINKED);
588 if (inode && !IS_ERR(inode)) {
589 d_prune_aliases(inode);
590 iput(inode);
591 }
592 out:
593 gfs2_glock_put(gl);
594 }
595
596 static void glock_work_func(struct work_struct *work)
597 {
598 unsigned long delay = 0;
599 struct gfs2_glock *gl = container_of(work, struct gfs2_glock, gl_work.work);
600 int drop_ref = 0;
601
602 if (test_and_clear_bit(GLF_REPLY_PENDING, &gl->gl_flags)) {
603 finish_xmote(gl, gl->gl_reply);
604 drop_ref = 1;
605 }
606 spin_lock(&gl->gl_lockref.lock);
607 if (test_bit(GLF_PENDING_DEMOTE, &gl->gl_flags) &&
608 gl->gl_state != LM_ST_UNLOCKED &&
609 gl->gl_demote_state != LM_ST_EXCLUSIVE) {
610 unsigned long holdtime, now = jiffies;
611
612 holdtime = gl->gl_tchange + gl->gl_hold_time;
613 if (time_before(now, holdtime))
614 delay = holdtime - now;
615
616 if (!delay) {
617 clear_bit(GLF_PENDING_DEMOTE, &gl->gl_flags);
618 set_bit(GLF_DEMOTE, &gl->gl_flags);
619 }
620 }
621 run_queue(gl, 0);
622 spin_unlock(&gl->gl_lockref.lock);
623 if (!delay)
624 gfs2_glock_put(gl);
625 else {
626 if (gl->gl_name.ln_type != LM_TYPE_INODE)
627 delay = 0;
628 if (queue_delayed_work(glock_workqueue, &gl->gl_work, delay) == 0)
629 gfs2_glock_put(gl);
630 }
631 if (drop_ref)
632 gfs2_glock_put(gl);
633 }
634
635 /**
636 * gfs2_glock_get() - Get a glock, or create one if one doesn't exist
637 * @sdp: The GFS2 superblock
638 * @number: the lock number
639 * @glops: The glock_operations to use
640 * @create: If 0, don't create the glock if it doesn't exist
641 * @glp: the glock is returned here
642 *
643 * This does not lock a glock, just finds/creates structures for one.
644 *
645 * Returns: errno
646 */
647
648 int gfs2_glock_get(struct gfs2_sbd *sdp, u64 number,
649 const struct gfs2_glock_operations *glops, int create,
650 struct gfs2_glock **glp)
651 {
652 struct super_block *s = sdp->sd_vfs;
653 struct lm_lockname name = { .ln_number = number,
654 .ln_type = glops->go_type,
655 .ln_sbd = sdp };
656 struct gfs2_glock *gl, *tmp = NULL;
657 struct address_space *mapping;
658 struct kmem_cache *cachep;
659 int ret, tries = 0;
660
661 rcu_read_lock();
662 gl = rhashtable_lookup_fast(&gl_hash_table, &name, ht_parms);
663 if (gl && !lockref_get_not_dead(&gl->gl_lockref))
664 gl = NULL;
665 rcu_read_unlock();
666
667 *glp = gl;
668 if (gl)
669 return 0;
670 if (!create)
671 return -ENOENT;
672
673 if (glops->go_flags & GLOF_ASPACE)
674 cachep = gfs2_glock_aspace_cachep;
675 else
676 cachep = gfs2_glock_cachep;
677 gl = kmem_cache_alloc(cachep, GFP_NOFS);
678 if (!gl)
679 return -ENOMEM;
680
681 memset(&gl->gl_lksb, 0, sizeof(struct dlm_lksb));
682
683 if (glops->go_flags & GLOF_LVB) {
684 gl->gl_lksb.sb_lvbptr = kzalloc(GFS2_MIN_LVB_SIZE, GFP_NOFS);
685 if (!gl->gl_lksb.sb_lvbptr) {
686 kmem_cache_free(cachep, gl);
687 return -ENOMEM;
688 }
689 }
690
691 atomic_inc(&sdp->sd_glock_disposal);
692 gl->gl_node.next = NULL;
693 gl->gl_flags = 0;
694 gl->gl_name = name;
695 gl->gl_lockref.count = 1;
696 gl->gl_state = LM_ST_UNLOCKED;
697 gl->gl_target = LM_ST_UNLOCKED;
698 gl->gl_demote_state = LM_ST_EXCLUSIVE;
699 gl->gl_ops = glops;
700 gl->gl_dstamp = ktime_set(0, 0);
701 preempt_disable();
702 /* We use the global stats to estimate the initial per-glock stats */
703 gl->gl_stats = this_cpu_ptr(sdp->sd_lkstats)->lkstats[glops->go_type];
704 preempt_enable();
705 gl->gl_stats.stats[GFS2_LKS_DCOUNT] = 0;
706 gl->gl_stats.stats[GFS2_LKS_QCOUNT] = 0;
707 gl->gl_tchange = jiffies;
708 gl->gl_object = NULL;
709 gl->gl_hold_time = GL_GLOCK_DFT_HOLD;
710 INIT_DELAYED_WORK(&gl->gl_work, glock_work_func);
711 INIT_WORK(&gl->gl_delete, delete_work_func);
712
713 mapping = gfs2_glock2aspace(gl);
714 if (mapping) {
715 mapping->a_ops = &gfs2_meta_aops;
716 mapping->host = s->s_bdev->bd_inode;
717 mapping->flags = 0;
718 mapping_set_gfp_mask(mapping, GFP_NOFS);
719 mapping->private_data = NULL;
720 mapping->writeback_index = 0;
721 }
722
723 again:
724 ret = rhashtable_lookup_insert_fast(&gl_hash_table, &gl->gl_node,
725 ht_parms);
726 if (ret == 0) {
727 *glp = gl;
728 return 0;
729 }
730
731 if (ret == -EEXIST) {
732 ret = 0;
733 rcu_read_lock();
734 tmp = rhashtable_lookup_fast(&gl_hash_table, &name, ht_parms);
735 if (tmp == NULL || !lockref_get_not_dead(&tmp->gl_lockref)) {
736 if (++tries < 100) {
737 rcu_read_unlock();
738 cond_resched();
739 goto again;
740 }
741 tmp = NULL;
742 ret = -ENOMEM;
743 }
744 rcu_read_unlock();
745 } else {
746 WARN_ON_ONCE(ret);
747 }
748 kfree(gl->gl_lksb.sb_lvbptr);
749 kmem_cache_free(cachep, gl);
750 atomic_dec(&sdp->sd_glock_disposal);
751 *glp = tmp;
752
753 return ret;
754 }
755
756 /**
757 * gfs2_holder_init - initialize a struct gfs2_holder in the default way
758 * @gl: the glock
759 * @state: the state we're requesting
760 * @flags: the modifier flags
761 * @gh: the holder structure
762 *
763 */
764
765 void gfs2_holder_init(struct gfs2_glock *gl, unsigned int state, u16 flags,
766 struct gfs2_holder *gh)
767 {
768 INIT_LIST_HEAD(&gh->gh_list);
769 gh->gh_gl = gl;
770 gh->gh_ip = _RET_IP_;
771 gh->gh_owner_pid = get_pid(task_pid(current));
772 gh->gh_state = state;
773 gh->gh_flags = flags;
774 gh->gh_error = 0;
775 gh->gh_iflags = 0;
776 gfs2_glock_hold(gl);
777 }
778
779 /**
780 * gfs2_holder_reinit - reinitialize a struct gfs2_holder so we can requeue it
781 * @state: the state we're requesting
782 * @flags: the modifier flags
783 * @gh: the holder structure
784 *
785 * Don't mess with the glock.
786 *
787 */
788
789 void gfs2_holder_reinit(unsigned int state, u16 flags, struct gfs2_holder *gh)
790 {
791 gh->gh_state = state;
792 gh->gh_flags = flags;
793 gh->gh_iflags = 0;
794 gh->gh_ip = _RET_IP_;
795 put_pid(gh->gh_owner_pid);
796 gh->gh_owner_pid = get_pid(task_pid(current));
797 }
798
799 /**
800 * gfs2_holder_uninit - uninitialize a holder structure (drop glock reference)
801 * @gh: the holder structure
802 *
803 */
804
805 void gfs2_holder_uninit(struct gfs2_holder *gh)
806 {
807 put_pid(gh->gh_owner_pid);
808 gfs2_glock_put(gh->gh_gl);
809 gfs2_holder_mark_uninitialized(gh);
810 gh->gh_ip = 0;
811 }
812
813 /**
814 * gfs2_glock_wait - wait on a glock acquisition
815 * @gh: the glock holder
816 *
817 * Returns: 0 on success
818 */
819
820 int gfs2_glock_wait(struct gfs2_holder *gh)
821 {
822 unsigned long time1 = jiffies;
823
824 might_sleep();
825 wait_on_bit(&gh->gh_iflags, HIF_WAIT, TASK_UNINTERRUPTIBLE);
826 if (time_after(jiffies, time1 + HZ)) /* have we waited > a second? */
827 /* Lengthen the minimum hold time. */
828 gh->gh_gl->gl_hold_time = min(gh->gh_gl->gl_hold_time +
829 GL_GLOCK_HOLD_INCR,
830 GL_GLOCK_MAX_HOLD);
831 return gh->gh_error;
832 }
833
834 /**
835 * handle_callback - process a demote request
836 * @gl: the glock
837 * @state: the state the caller wants us to change to
838 *
839 * There are only two requests that we are going to see in actual
840 * practise: LM_ST_SHARED and LM_ST_UNLOCKED
841 */
842
843 static void handle_callback(struct gfs2_glock *gl, unsigned int state,
844 unsigned long delay, bool remote)
845 {
846 int bit = delay ? GLF_PENDING_DEMOTE : GLF_DEMOTE;
847
848 set_bit(bit, &gl->gl_flags);
849 if (gl->gl_demote_state == LM_ST_EXCLUSIVE) {
850 gl->gl_demote_state = state;
851 gl->gl_demote_time = jiffies;
852 } else if (gl->gl_demote_state != LM_ST_UNLOCKED &&
853 gl->gl_demote_state != state) {
854 gl->gl_demote_state = LM_ST_UNLOCKED;
855 }
856 if (gl->gl_ops->go_callback)
857 gl->gl_ops->go_callback(gl, remote);
858 trace_gfs2_demote_rq(gl, remote);
859 }
860
861 void gfs2_print_dbg(struct seq_file *seq, const char *fmt, ...)
862 {
863 struct va_format vaf;
864 va_list args;
865
866 va_start(args, fmt);
867
868 if (seq) {
869 seq_vprintf(seq, fmt, args);
870 } else {
871 vaf.fmt = fmt;
872 vaf.va = &args;
873
874 pr_err("%pV", &vaf);
875 }
876
877 va_end(args);
878 }
879
880 /**
881 * add_to_queue - Add a holder to the wait queue (but look for recursion)
882 * @gh: the holder structure to add
883 *
884 * Eventually we should move the recursive locking trap to a
885 * debugging option or something like that. This is the fast
886 * path and needs to have the minimum number of distractions.
887 *
888 */
889
890 static inline void add_to_queue(struct gfs2_holder *gh)
891 __releases(&gl->gl_lockref.lock)
892 __acquires(&gl->gl_lockref.lock)
893 {
894 struct gfs2_glock *gl = gh->gh_gl;
895 struct gfs2_sbd *sdp = gl->gl_name.ln_sbd;
896 struct list_head *insert_pt = NULL;
897 struct gfs2_holder *gh2;
898 int try_futile = 0;
899
900 BUG_ON(gh->gh_owner_pid == NULL);
901 if (test_and_set_bit(HIF_WAIT, &gh->gh_iflags))
902 BUG();
903
904 if (gh->gh_flags & (LM_FLAG_TRY | LM_FLAG_TRY_1CB)) {
905 if (test_bit(GLF_LOCK, &gl->gl_flags))
906 try_futile = !may_grant(gl, gh);
907 if (test_bit(GLF_INVALIDATE_IN_PROGRESS, &gl->gl_flags))
908 goto fail;
909 }
910
911 list_for_each_entry(gh2, &gl->gl_holders, gh_list) {
912 if (unlikely(gh2->gh_owner_pid == gh->gh_owner_pid &&
913 (gh->gh_gl->gl_ops->go_type != LM_TYPE_FLOCK)))
914 goto trap_recursive;
915 if (try_futile &&
916 !(gh2->gh_flags & (LM_FLAG_TRY | LM_FLAG_TRY_1CB))) {
917 fail:
918 gh->gh_error = GLR_TRYFAILED;
919 gfs2_holder_wake(gh);
920 return;
921 }
922 if (test_bit(HIF_HOLDER, &gh2->gh_iflags))
923 continue;
924 if (unlikely((gh->gh_flags & LM_FLAG_PRIORITY) && !insert_pt))
925 insert_pt = &gh2->gh_list;
926 }
927 set_bit(GLF_QUEUED, &gl->gl_flags);
928 trace_gfs2_glock_queue(gh, 1);
929 gfs2_glstats_inc(gl, GFS2_LKS_QCOUNT);
930 gfs2_sbstats_inc(gl, GFS2_LKS_QCOUNT);
931 if (likely(insert_pt == NULL)) {
932 list_add_tail(&gh->gh_list, &gl->gl_holders);
933 if (unlikely(gh->gh_flags & LM_FLAG_PRIORITY))
934 goto do_cancel;
935 return;
936 }
937 list_add_tail(&gh->gh_list, insert_pt);
938 do_cancel:
939 gh = list_entry(gl->gl_holders.next, struct gfs2_holder, gh_list);
940 if (!(gh->gh_flags & LM_FLAG_PRIORITY)) {
941 spin_unlock(&gl->gl_lockref.lock);
942 if (sdp->sd_lockstruct.ls_ops->lm_cancel)
943 sdp->sd_lockstruct.ls_ops->lm_cancel(gl);
944 spin_lock(&gl->gl_lockref.lock);
945 }
946 return;
947
948 trap_recursive:
949 pr_err("original: %pSR\n", (void *)gh2->gh_ip);
950 pr_err("pid: %d\n", pid_nr(gh2->gh_owner_pid));
951 pr_err("lock type: %d req lock state : %d\n",
952 gh2->gh_gl->gl_name.ln_type, gh2->gh_state);
953 pr_err("new: %pSR\n", (void *)gh->gh_ip);
954 pr_err("pid: %d\n", pid_nr(gh->gh_owner_pid));
955 pr_err("lock type: %d req lock state : %d\n",
956 gh->gh_gl->gl_name.ln_type, gh->gh_state);
957 gfs2_dump_glock(NULL, gl);
958 BUG();
959 }
960
961 /**
962 * gfs2_glock_nq - enqueue a struct gfs2_holder onto a glock (acquire a glock)
963 * @gh: the holder structure
964 *
965 * if (gh->gh_flags & GL_ASYNC), this never returns an error
966 *
967 * Returns: 0, GLR_TRYFAILED, or errno on failure
968 */
969
970 int gfs2_glock_nq(struct gfs2_holder *gh)
971 {
972 struct gfs2_glock *gl = gh->gh_gl;
973 struct gfs2_sbd *sdp = gl->gl_name.ln_sbd;
974 int error = 0;
975
976 if (unlikely(test_bit(SDF_SHUTDOWN, &sdp->sd_flags)))
977 return -EIO;
978
979 if (test_bit(GLF_LRU, &gl->gl_flags))
980 gfs2_glock_remove_from_lru(gl);
981
982 spin_lock(&gl->gl_lockref.lock);
983 add_to_queue(gh);
984 if (unlikely((LM_FLAG_NOEXP & gh->gh_flags) &&
985 test_and_clear_bit(GLF_FROZEN, &gl->gl_flags))) {
986 set_bit(GLF_REPLY_PENDING, &gl->gl_flags);
987 gl->gl_lockref.count++;
988 if (queue_delayed_work(glock_workqueue, &gl->gl_work, 0) == 0)
989 gl->gl_lockref.count--;
990 }
991 run_queue(gl, 1);
992 spin_unlock(&gl->gl_lockref.lock);
993
994 if (!(gh->gh_flags & GL_ASYNC))
995 error = gfs2_glock_wait(gh);
996
997 return error;
998 }
999
1000 /**
1001 * gfs2_glock_poll - poll to see if an async request has been completed
1002 * @gh: the holder
1003 *
1004 * Returns: 1 if the request is ready to be gfs2_glock_wait()ed on
1005 */
1006
1007 int gfs2_glock_poll(struct gfs2_holder *gh)
1008 {
1009 return test_bit(HIF_WAIT, &gh->gh_iflags) ? 0 : 1;
1010 }
1011
1012 /**
1013 * gfs2_glock_dq - dequeue a struct gfs2_holder from a glock (release a glock)
1014 * @gh: the glock holder
1015 *
1016 */
1017
1018 void gfs2_glock_dq(struct gfs2_holder *gh)
1019 {
1020 struct gfs2_glock *gl = gh->gh_gl;
1021 const struct gfs2_glock_operations *glops = gl->gl_ops;
1022 unsigned delay = 0;
1023 int fast_path = 0;
1024
1025 spin_lock(&gl->gl_lockref.lock);
1026 if (gh->gh_flags & GL_NOCACHE)
1027 handle_callback(gl, LM_ST_UNLOCKED, 0, false);
1028
1029 list_del_init(&gh->gh_list);
1030 clear_bit(HIF_HOLDER, &gh->gh_iflags);
1031 if (find_first_holder(gl) == NULL) {
1032 if (glops->go_unlock) {
1033 GLOCK_BUG_ON(gl, test_and_set_bit(GLF_LOCK, &gl->gl_flags));
1034 spin_unlock(&gl->gl_lockref.lock);
1035 glops->go_unlock(gh);
1036 spin_lock(&gl->gl_lockref.lock);
1037 clear_bit(GLF_LOCK, &gl->gl_flags);
1038 }
1039 if (list_empty(&gl->gl_holders) &&
1040 !test_bit(GLF_PENDING_DEMOTE, &gl->gl_flags) &&
1041 !test_bit(GLF_DEMOTE, &gl->gl_flags))
1042 fast_path = 1;
1043 }
1044 if (!test_bit(GLF_LFLUSH, &gl->gl_flags) && demote_ok(gl) &&
1045 (glops->go_flags & GLOF_LRU))
1046 gfs2_glock_add_to_lru(gl);
1047
1048 trace_gfs2_glock_queue(gh, 0);
1049 spin_unlock(&gl->gl_lockref.lock);
1050 if (likely(fast_path))
1051 return;
1052
1053 gfs2_glock_hold(gl);
1054 if (test_bit(GLF_PENDING_DEMOTE, &gl->gl_flags) &&
1055 !test_bit(GLF_DEMOTE, &gl->gl_flags) &&
1056 gl->gl_name.ln_type == LM_TYPE_INODE)
1057 delay = gl->gl_hold_time;
1058 if (queue_delayed_work(glock_workqueue, &gl->gl_work, delay) == 0)
1059 gfs2_glock_put(gl);
1060 }
1061
1062 void gfs2_glock_dq_wait(struct gfs2_holder *gh)
1063 {
1064 struct gfs2_glock *gl = gh->gh_gl;
1065 gfs2_glock_dq(gh);
1066 might_sleep();
1067 wait_on_bit(&gl->gl_flags, GLF_DEMOTE, TASK_UNINTERRUPTIBLE);
1068 }
1069
1070 /**
1071 * gfs2_glock_dq_uninit - dequeue a holder from a glock and initialize it
1072 * @gh: the holder structure
1073 *
1074 */
1075
1076 void gfs2_glock_dq_uninit(struct gfs2_holder *gh)
1077 {
1078 gfs2_glock_dq(gh);
1079 gfs2_holder_uninit(gh);
1080 }
1081
1082 /**
1083 * gfs2_glock_nq_num - acquire a glock based on lock number
1084 * @sdp: the filesystem
1085 * @number: the lock number
1086 * @glops: the glock operations for the type of glock
1087 * @state: the state to acquire the glock in
1088 * @flags: modifier flags for the acquisition
1089 * @gh: the struct gfs2_holder
1090 *
1091 * Returns: errno
1092 */
1093
1094 int gfs2_glock_nq_num(struct gfs2_sbd *sdp, u64 number,
1095 const struct gfs2_glock_operations *glops,
1096 unsigned int state, u16 flags, struct gfs2_holder *gh)
1097 {
1098 struct gfs2_glock *gl;
1099 int error;
1100
1101 error = gfs2_glock_get(sdp, number, glops, CREATE, &gl);
1102 if (!error) {
1103 error = gfs2_glock_nq_init(gl, state, flags, gh);
1104 gfs2_glock_put(gl);
1105 }
1106
1107 return error;
1108 }
1109
1110 /**
1111 * glock_compare - Compare two struct gfs2_glock structures for sorting
1112 * @arg_a: the first structure
1113 * @arg_b: the second structure
1114 *
1115 */
1116
1117 static int glock_compare(const void *arg_a, const void *arg_b)
1118 {
1119 const struct gfs2_holder *gh_a = *(const struct gfs2_holder **)arg_a;
1120 const struct gfs2_holder *gh_b = *(const struct gfs2_holder **)arg_b;
1121 const struct lm_lockname *a = &gh_a->gh_gl->gl_name;
1122 const struct lm_lockname *b = &gh_b->gh_gl->gl_name;
1123
1124 if (a->ln_number > b->ln_number)
1125 return 1;
1126 if (a->ln_number < b->ln_number)
1127 return -1;
1128 BUG_ON(gh_a->gh_gl->gl_ops->go_type == gh_b->gh_gl->gl_ops->go_type);
1129 return 0;
1130 }
1131
1132 /**
1133 * nq_m_sync - synchonously acquire more than one glock in deadlock free order
1134 * @num_gh: the number of structures
1135 * @ghs: an array of struct gfs2_holder structures
1136 *
1137 * Returns: 0 on success (all glocks acquired),
1138 * errno on failure (no glocks acquired)
1139 */
1140
1141 static int nq_m_sync(unsigned int num_gh, struct gfs2_holder *ghs,
1142 struct gfs2_holder **p)
1143 {
1144 unsigned int x;
1145 int error = 0;
1146
1147 for (x = 0; x < num_gh; x++)
1148 p[x] = &ghs[x];
1149
1150 sort(p, num_gh, sizeof(struct gfs2_holder *), glock_compare, NULL);
1151
1152 for (x = 0; x < num_gh; x++) {
1153 p[x]->gh_flags &= ~(LM_FLAG_TRY | GL_ASYNC);
1154
1155 error = gfs2_glock_nq(p[x]);
1156 if (error) {
1157 while (x--)
1158 gfs2_glock_dq(p[x]);
1159 break;
1160 }
1161 }
1162
1163 return error;
1164 }
1165
1166 /**
1167 * gfs2_glock_nq_m - acquire multiple glocks
1168 * @num_gh: the number of structures
1169 * @ghs: an array of struct gfs2_holder structures
1170 *
1171 *
1172 * Returns: 0 on success (all glocks acquired),
1173 * errno on failure (no glocks acquired)
1174 */
1175
1176 int gfs2_glock_nq_m(unsigned int num_gh, struct gfs2_holder *ghs)
1177 {
1178 struct gfs2_holder *tmp[4];
1179 struct gfs2_holder **pph = tmp;
1180 int error = 0;
1181
1182 switch(num_gh) {
1183 case 0:
1184 return 0;
1185 case 1:
1186 ghs->gh_flags &= ~(LM_FLAG_TRY | GL_ASYNC);
1187 return gfs2_glock_nq(ghs);
1188 default:
1189 if (num_gh <= 4)
1190 break;
1191 pph = kmalloc(num_gh * sizeof(struct gfs2_holder *), GFP_NOFS);
1192 if (!pph)
1193 return -ENOMEM;
1194 }
1195
1196 error = nq_m_sync(num_gh, ghs, pph);
1197
1198 if (pph != tmp)
1199 kfree(pph);
1200
1201 return error;
1202 }
1203
1204 /**
1205 * gfs2_glock_dq_m - release multiple glocks
1206 * @num_gh: the number of structures
1207 * @ghs: an array of struct gfs2_holder structures
1208 *
1209 */
1210
1211 void gfs2_glock_dq_m(unsigned int num_gh, struct gfs2_holder *ghs)
1212 {
1213 while (num_gh--)
1214 gfs2_glock_dq(&ghs[num_gh]);
1215 }
1216
1217 void gfs2_glock_cb(struct gfs2_glock *gl, unsigned int state)
1218 {
1219 unsigned long delay = 0;
1220 unsigned long holdtime;
1221 unsigned long now = jiffies;
1222
1223 gfs2_glock_hold(gl);
1224 holdtime = gl->gl_tchange + gl->gl_hold_time;
1225 if (test_bit(GLF_QUEUED, &gl->gl_flags) &&
1226 gl->gl_name.ln_type == LM_TYPE_INODE) {
1227 if (time_before(now, holdtime))
1228 delay = holdtime - now;
1229 if (test_bit(GLF_REPLY_PENDING, &gl->gl_flags))
1230 delay = gl->gl_hold_time;
1231 }
1232
1233 spin_lock(&gl->gl_lockref.lock);
1234 handle_callback(gl, state, delay, true);
1235 spin_unlock(&gl->gl_lockref.lock);
1236 if (queue_delayed_work(glock_workqueue, &gl->gl_work, delay) == 0)
1237 gfs2_glock_put(gl);
1238 }
1239
1240 /**
1241 * gfs2_should_freeze - Figure out if glock should be frozen
1242 * @gl: The glock in question
1243 *
1244 * Glocks are not frozen if (a) the result of the dlm operation is
1245 * an error, (b) the locking operation was an unlock operation or
1246 * (c) if there is a "noexp" flagged request anywhere in the queue
1247 *
1248 * Returns: 1 if freezing should occur, 0 otherwise
1249 */
1250
1251 static int gfs2_should_freeze(const struct gfs2_glock *gl)
1252 {
1253 const struct gfs2_holder *gh;
1254
1255 if (gl->gl_reply & ~LM_OUT_ST_MASK)
1256 return 0;
1257 if (gl->gl_target == LM_ST_UNLOCKED)
1258 return 0;
1259
1260 list_for_each_entry(gh, &gl->gl_holders, gh_list) {
1261 if (test_bit(HIF_HOLDER, &gh->gh_iflags))
1262 continue;
1263 if (LM_FLAG_NOEXP & gh->gh_flags)
1264 return 0;
1265 }
1266
1267 return 1;
1268 }
1269
1270 /**
1271 * gfs2_glock_complete - Callback used by locking
1272 * @gl: Pointer to the glock
1273 * @ret: The return value from the dlm
1274 *
1275 * The gl_reply field is under the gl_lockref.lock lock so that it is ok
1276 * to use a bitfield shared with other glock state fields.
1277 */
1278
1279 void gfs2_glock_complete(struct gfs2_glock *gl, int ret)
1280 {
1281 struct lm_lockstruct *ls = &gl->gl_name.ln_sbd->sd_lockstruct;
1282
1283 spin_lock(&gl->gl_lockref.lock);
1284 gl->gl_reply = ret;
1285
1286 if (unlikely(test_bit(DFL_BLOCK_LOCKS, &ls->ls_recover_flags))) {
1287 if (gfs2_should_freeze(gl)) {
1288 set_bit(GLF_FROZEN, &gl->gl_flags);
1289 spin_unlock(&gl->gl_lockref.lock);
1290 return;
1291 }
1292 }
1293
1294 gl->gl_lockref.count++;
1295 set_bit(GLF_REPLY_PENDING, &gl->gl_flags);
1296 spin_unlock(&gl->gl_lockref.lock);
1297
1298 if (queue_delayed_work(glock_workqueue, &gl->gl_work, 0) == 0)
1299 gfs2_glock_put(gl);
1300 }
1301
1302 static int glock_cmp(void *priv, struct list_head *a, struct list_head *b)
1303 {
1304 struct gfs2_glock *gla, *glb;
1305
1306 gla = list_entry(a, struct gfs2_glock, gl_lru);
1307 glb = list_entry(b, struct gfs2_glock, gl_lru);
1308
1309 if (gla->gl_name.ln_number > glb->gl_name.ln_number)
1310 return 1;
1311 if (gla->gl_name.ln_number < glb->gl_name.ln_number)
1312 return -1;
1313
1314 return 0;
1315 }
1316
1317 /**
1318 * gfs2_dispose_glock_lru - Demote a list of glocks
1319 * @list: The list to dispose of
1320 *
1321 * Disposing of glocks may involve disk accesses, so that here we sort
1322 * the glocks by number (i.e. disk location of the inodes) so that if
1323 * there are any such accesses, they'll be sent in order (mostly).
1324 *
1325 * Must be called under the lru_lock, but may drop and retake this
1326 * lock. While the lru_lock is dropped, entries may vanish from the
1327 * list, but no new entries will appear on the list (since it is
1328 * private)
1329 */
1330
1331 static void gfs2_dispose_glock_lru(struct list_head *list)
1332 __releases(&lru_lock)
1333 __acquires(&lru_lock)
1334 {
1335 struct gfs2_glock *gl;
1336
1337 list_sort(NULL, list, glock_cmp);
1338
1339 while(!list_empty(list)) {
1340 gl = list_entry(list->next, struct gfs2_glock, gl_lru);
1341 list_del_init(&gl->gl_lru);
1342 if (!spin_trylock(&gl->gl_lockref.lock)) {
1343 add_back_to_lru:
1344 list_add(&gl->gl_lru, &lru_list);
1345 atomic_inc(&lru_count);
1346 continue;
1347 }
1348 if (test_and_set_bit(GLF_LOCK, &gl->gl_flags)) {
1349 spin_unlock(&gl->gl_lockref.lock);
1350 goto add_back_to_lru;
1351 }
1352 clear_bit(GLF_LRU, &gl->gl_flags);
1353 gl->gl_lockref.count++;
1354 if (demote_ok(gl))
1355 handle_callback(gl, LM_ST_UNLOCKED, 0, false);
1356 WARN_ON(!test_and_clear_bit(GLF_LOCK, &gl->gl_flags));
1357 if (queue_delayed_work(glock_workqueue, &gl->gl_work, 0) == 0)
1358 gl->gl_lockref.count--;
1359 spin_unlock(&gl->gl_lockref.lock);
1360 cond_resched_lock(&lru_lock);
1361 }
1362 }
1363
1364 /**
1365 * gfs2_scan_glock_lru - Scan the LRU looking for locks to demote
1366 * @nr: The number of entries to scan
1367 *
1368 * This function selects the entries on the LRU which are able to
1369 * be demoted, and then kicks off the process by calling
1370 * gfs2_dispose_glock_lru() above.
1371 */
1372
1373 static long gfs2_scan_glock_lru(int nr)
1374 {
1375 struct gfs2_glock *gl;
1376 LIST_HEAD(skipped);
1377 LIST_HEAD(dispose);
1378 long freed = 0;
1379
1380 spin_lock(&lru_lock);
1381 while ((nr-- >= 0) && !list_empty(&lru_list)) {
1382 gl = list_entry(lru_list.next, struct gfs2_glock, gl_lru);
1383
1384 /* Test for being demotable */
1385 if (!test_bit(GLF_LOCK, &gl->gl_flags)) {
1386 list_move(&gl->gl_lru, &dispose);
1387 atomic_dec(&lru_count);
1388 freed++;
1389 continue;
1390 }
1391
1392 list_move(&gl->gl_lru, &skipped);
1393 }
1394 list_splice(&skipped, &lru_list);
1395 if (!list_empty(&dispose))
1396 gfs2_dispose_glock_lru(&dispose);
1397 spin_unlock(&lru_lock);
1398
1399 return freed;
1400 }
1401
1402 static unsigned long gfs2_glock_shrink_scan(struct shrinker *shrink,
1403 struct shrink_control *sc)
1404 {
1405 if (!(sc->gfp_mask & __GFP_FS))
1406 return SHRINK_STOP;
1407 return gfs2_scan_glock_lru(sc->nr_to_scan);
1408 }
1409
1410 static unsigned long gfs2_glock_shrink_count(struct shrinker *shrink,
1411 struct shrink_control *sc)
1412 {
1413 return vfs_pressure_ratio(atomic_read(&lru_count));
1414 }
1415
1416 static struct shrinker glock_shrinker = {
1417 .seeks = DEFAULT_SEEKS,
1418 .count_objects = gfs2_glock_shrink_count,
1419 .scan_objects = gfs2_glock_shrink_scan,
1420 };
1421
1422 /**
1423 * examine_bucket - Call a function for glock in a hash bucket
1424 * @examiner: the function
1425 * @sdp: the filesystem
1426 * @bucket: the bucket
1427 *
1428 */
1429
1430 static void glock_hash_walk(glock_examiner examiner, const struct gfs2_sbd *sdp)
1431 {
1432 struct gfs2_glock *gl;
1433 struct rhash_head *pos;
1434 const struct bucket_table *tbl;
1435 int i;
1436
1437 rcu_read_lock();
1438 tbl = rht_dereference_rcu(gl_hash_table.tbl, &gl_hash_table);
1439 for (i = 0; i < tbl->size; i++) {
1440 rht_for_each_entry_rcu(gl, pos, tbl, i, gl_node) {
1441 if ((gl->gl_name.ln_sbd == sdp) &&
1442 lockref_get_not_dead(&gl->gl_lockref))
1443 examiner(gl);
1444 }
1445 }
1446 rcu_read_unlock();
1447 cond_resched();
1448 }
1449
1450 /**
1451 * thaw_glock - thaw out a glock which has an unprocessed reply waiting
1452 * @gl: The glock to thaw
1453 *
1454 */
1455
1456 static void thaw_glock(struct gfs2_glock *gl)
1457 {
1458 if (!test_and_clear_bit(GLF_FROZEN, &gl->gl_flags))
1459 goto out;
1460 set_bit(GLF_REPLY_PENDING, &gl->gl_flags);
1461 if (queue_delayed_work(glock_workqueue, &gl->gl_work, 0) == 0) {
1462 out:
1463 gfs2_glock_put(gl);
1464 }
1465 }
1466
1467 /**
1468 * clear_glock - look at a glock and see if we can free it from glock cache
1469 * @gl: the glock to look at
1470 *
1471 */
1472
1473 static void clear_glock(struct gfs2_glock *gl)
1474 {
1475 gfs2_glock_remove_from_lru(gl);
1476
1477 spin_lock(&gl->gl_lockref.lock);
1478 if (gl->gl_state != LM_ST_UNLOCKED)
1479 handle_callback(gl, LM_ST_UNLOCKED, 0, false);
1480 spin_unlock(&gl->gl_lockref.lock);
1481 if (queue_delayed_work(glock_workqueue, &gl->gl_work, 0) == 0)
1482 gfs2_glock_put(gl);
1483 }
1484
1485 /**
1486 * gfs2_glock_thaw - Thaw any frozen glocks
1487 * @sdp: The super block
1488 *
1489 */
1490
1491 void gfs2_glock_thaw(struct gfs2_sbd *sdp)
1492 {
1493 glock_hash_walk(thaw_glock, sdp);
1494 }
1495
1496 static void dump_glock(struct seq_file *seq, struct gfs2_glock *gl)
1497 {
1498 spin_lock(&gl->gl_lockref.lock);
1499 gfs2_dump_glock(seq, gl);
1500 spin_unlock(&gl->gl_lockref.lock);
1501 }
1502
1503 static void dump_glock_func(struct gfs2_glock *gl)
1504 {
1505 dump_glock(NULL, gl);
1506 }
1507
1508 /**
1509 * gfs2_gl_hash_clear - Empty out the glock hash table
1510 * @sdp: the filesystem
1511 * @wait: wait until it's all gone
1512 *
1513 * Called when unmounting the filesystem.
1514 */
1515
1516 void gfs2_gl_hash_clear(struct gfs2_sbd *sdp)
1517 {
1518 set_bit(SDF_SKIP_DLM_UNLOCK, &sdp->sd_flags);
1519 flush_workqueue(glock_workqueue);
1520 glock_hash_walk(clear_glock, sdp);
1521 flush_workqueue(glock_workqueue);
1522 wait_event_timeout(sdp->sd_glock_wait,
1523 atomic_read(&sdp->sd_glock_disposal) == 0,
1524 HZ * 600);
1525 glock_hash_walk(dump_glock_func, sdp);
1526 }
1527
1528 void gfs2_glock_finish_truncate(struct gfs2_inode *ip)
1529 {
1530 struct gfs2_glock *gl = ip->i_gl;
1531 int ret;
1532
1533 ret = gfs2_truncatei_resume(ip);
1534 gfs2_assert_withdraw(gl->gl_name.ln_sbd, ret == 0);
1535
1536 spin_lock(&gl->gl_lockref.lock);
1537 clear_bit(GLF_LOCK, &gl->gl_flags);
1538 run_queue(gl, 1);
1539 spin_unlock(&gl->gl_lockref.lock);
1540 }
1541
1542 static const char *state2str(unsigned state)
1543 {
1544 switch(state) {
1545 case LM_ST_UNLOCKED:
1546 return "UN";
1547 case LM_ST_SHARED:
1548 return "SH";
1549 case LM_ST_DEFERRED:
1550 return "DF";
1551 case LM_ST_EXCLUSIVE:
1552 return "EX";
1553 }
1554 return "??";
1555 }
1556
1557 static const char *hflags2str(char *buf, u16 flags, unsigned long iflags)
1558 {
1559 char *p = buf;
1560 if (flags & LM_FLAG_TRY)
1561 *p++ = 't';
1562 if (flags & LM_FLAG_TRY_1CB)
1563 *p++ = 'T';
1564 if (flags & LM_FLAG_NOEXP)
1565 *p++ = 'e';
1566 if (flags & LM_FLAG_ANY)
1567 *p++ = 'A';
1568 if (flags & LM_FLAG_PRIORITY)
1569 *p++ = 'p';
1570 if (flags & GL_ASYNC)
1571 *p++ = 'a';
1572 if (flags & GL_EXACT)
1573 *p++ = 'E';
1574 if (flags & GL_NOCACHE)
1575 *p++ = 'c';
1576 if (test_bit(HIF_HOLDER, &iflags))
1577 *p++ = 'H';
1578 if (test_bit(HIF_WAIT, &iflags))
1579 *p++ = 'W';
1580 if (test_bit(HIF_FIRST, &iflags))
1581 *p++ = 'F';
1582 *p = 0;
1583 return buf;
1584 }
1585
1586 /**
1587 * dump_holder - print information about a glock holder
1588 * @seq: the seq_file struct
1589 * @gh: the glock holder
1590 *
1591 */
1592
1593 static void dump_holder(struct seq_file *seq, const struct gfs2_holder *gh)
1594 {
1595 struct task_struct *gh_owner = NULL;
1596 char flags_buf[32];
1597
1598 rcu_read_lock();
1599 if (gh->gh_owner_pid)
1600 gh_owner = pid_task(gh->gh_owner_pid, PIDTYPE_PID);
1601 gfs2_print_dbg(seq, " H: s:%s f:%s e:%d p:%ld [%s] %pS\n",
1602 state2str(gh->gh_state),
1603 hflags2str(flags_buf, gh->gh_flags, gh->gh_iflags),
1604 gh->gh_error,
1605 gh->gh_owner_pid ? (long)pid_nr(gh->gh_owner_pid) : -1,
1606 gh_owner ? gh_owner->comm : "(ended)",
1607 (void *)gh->gh_ip);
1608 rcu_read_unlock();
1609 }
1610
1611 static const char *gflags2str(char *buf, const struct gfs2_glock *gl)
1612 {
1613 const unsigned long *gflags = &gl->gl_flags;
1614 char *p = buf;
1615
1616 if (test_bit(GLF_LOCK, gflags))
1617 *p++ = 'l';
1618 if (test_bit(GLF_DEMOTE, gflags))
1619 *p++ = 'D';
1620 if (test_bit(GLF_PENDING_DEMOTE, gflags))
1621 *p++ = 'd';
1622 if (test_bit(GLF_DEMOTE_IN_PROGRESS, gflags))
1623 *p++ = 'p';
1624 if (test_bit(GLF_DIRTY, gflags))
1625 *p++ = 'y';
1626 if (test_bit(GLF_LFLUSH, gflags))
1627 *p++ = 'f';
1628 if (test_bit(GLF_INVALIDATE_IN_PROGRESS, gflags))
1629 *p++ = 'i';
1630 if (test_bit(GLF_REPLY_PENDING, gflags))
1631 *p++ = 'r';
1632 if (test_bit(GLF_INITIAL, gflags))
1633 *p++ = 'I';
1634 if (test_bit(GLF_FROZEN, gflags))
1635 *p++ = 'F';
1636 if (test_bit(GLF_QUEUED, gflags))
1637 *p++ = 'q';
1638 if (test_bit(GLF_LRU, gflags))
1639 *p++ = 'L';
1640 if (gl->gl_object)
1641 *p++ = 'o';
1642 if (test_bit(GLF_BLOCKING, gflags))
1643 *p++ = 'b';
1644 *p = 0;
1645 return buf;
1646 }
1647
1648 /**
1649 * gfs2_dump_glock - print information about a glock
1650 * @seq: The seq_file struct
1651 * @gl: the glock
1652 *
1653 * The file format is as follows:
1654 * One line per object, capital letters are used to indicate objects
1655 * G = glock, I = Inode, R = rgrp, H = holder. Glocks are not indented,
1656 * other objects are indented by a single space and follow the glock to
1657 * which they are related. Fields are indicated by lower case letters
1658 * followed by a colon and the field value, except for strings which are in
1659 * [] so that its possible to see if they are composed of spaces for
1660 * example. The field's are n = number (id of the object), f = flags,
1661 * t = type, s = state, r = refcount, e = error, p = pid.
1662 *
1663 */
1664
1665 void gfs2_dump_glock(struct seq_file *seq, const struct gfs2_glock *gl)
1666 {
1667 const struct gfs2_glock_operations *glops = gl->gl_ops;
1668 unsigned long long dtime;
1669 const struct gfs2_holder *gh;
1670 char gflags_buf[32];
1671
1672 dtime = jiffies - gl->gl_demote_time;
1673 dtime *= 1000000/HZ; /* demote time in uSec */
1674 if (!test_bit(GLF_DEMOTE, &gl->gl_flags))
1675 dtime = 0;
1676 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",
1677 state2str(gl->gl_state),
1678 gl->gl_name.ln_type,
1679 (unsigned long long)gl->gl_name.ln_number,
1680 gflags2str(gflags_buf, gl),
1681 state2str(gl->gl_target),
1682 state2str(gl->gl_demote_state), dtime,
1683 atomic_read(&gl->gl_ail_count),
1684 atomic_read(&gl->gl_revokes),
1685 (int)gl->gl_lockref.count, gl->gl_hold_time);
1686
1687 list_for_each_entry(gh, &gl->gl_holders, gh_list)
1688 dump_holder(seq, gh);
1689
1690 if (gl->gl_state != LM_ST_UNLOCKED && glops->go_dump)
1691 glops->go_dump(seq, gl);
1692 }
1693
1694 static int gfs2_glstats_seq_show(struct seq_file *seq, void *iter_ptr)
1695 {
1696 struct gfs2_glock *gl = iter_ptr;
1697
1698 seq_printf(seq, "G: n:%u/%llx rtt:%llu/%llu rttb:%llu/%llu irt:%llu/%llu dcnt: %llu qcnt: %llu\n",
1699 gl->gl_name.ln_type,
1700 (unsigned long long)gl->gl_name.ln_number,
1701 (unsigned long long)gl->gl_stats.stats[GFS2_LKS_SRTT],
1702 (unsigned long long)gl->gl_stats.stats[GFS2_LKS_SRTTVAR],
1703 (unsigned long long)gl->gl_stats.stats[GFS2_LKS_SRTTB],
1704 (unsigned long long)gl->gl_stats.stats[GFS2_LKS_SRTTVARB],
1705 (unsigned long long)gl->gl_stats.stats[GFS2_LKS_SIRT],
1706 (unsigned long long)gl->gl_stats.stats[GFS2_LKS_SIRTVAR],
1707 (unsigned long long)gl->gl_stats.stats[GFS2_LKS_DCOUNT],
1708 (unsigned long long)gl->gl_stats.stats[GFS2_LKS_QCOUNT]);
1709 return 0;
1710 }
1711
1712 static const char *gfs2_gltype[] = {
1713 "type",
1714 "reserved",
1715 "nondisk",
1716 "inode",
1717 "rgrp",
1718 "meta",
1719 "iopen",
1720 "flock",
1721 "plock",
1722 "quota",
1723 "journal",
1724 };
1725
1726 static const char *gfs2_stype[] = {
1727 [GFS2_LKS_SRTT] = "srtt",
1728 [GFS2_LKS_SRTTVAR] = "srttvar",
1729 [GFS2_LKS_SRTTB] = "srttb",
1730 [GFS2_LKS_SRTTVARB] = "srttvarb",
1731 [GFS2_LKS_SIRT] = "sirt",
1732 [GFS2_LKS_SIRTVAR] = "sirtvar",
1733 [GFS2_LKS_DCOUNT] = "dlm",
1734 [GFS2_LKS_QCOUNT] = "queue",
1735 };
1736
1737 #define GFS2_NR_SBSTATS (ARRAY_SIZE(gfs2_gltype) * ARRAY_SIZE(gfs2_stype))
1738
1739 static int gfs2_sbstats_seq_show(struct seq_file *seq, void *iter_ptr)
1740 {
1741 struct gfs2_sbd *sdp = seq->private;
1742 loff_t pos = *(loff_t *)iter_ptr;
1743 unsigned index = pos >> 3;
1744 unsigned subindex = pos & 0x07;
1745 int i;
1746
1747 if (index == 0 && subindex != 0)
1748 return 0;
1749
1750 seq_printf(seq, "%-10s %8s:", gfs2_gltype[index],
1751 (index == 0) ? "cpu": gfs2_stype[subindex]);
1752
1753 for_each_possible_cpu(i) {
1754 const struct gfs2_pcpu_lkstats *lkstats = per_cpu_ptr(sdp->sd_lkstats, i);
1755
1756 if (index == 0)
1757 seq_printf(seq, " %15u", i);
1758 else
1759 seq_printf(seq, " %15llu", (unsigned long long)lkstats->
1760 lkstats[index - 1].stats[subindex]);
1761 }
1762 seq_putc(seq, '\n');
1763 return 0;
1764 }
1765
1766 int __init gfs2_glock_init(void)
1767 {
1768 int ret;
1769
1770 ret = rhashtable_init(&gl_hash_table, &ht_parms);
1771 if (ret < 0)
1772 return ret;
1773
1774 glock_workqueue = alloc_workqueue("glock_workqueue", WQ_MEM_RECLAIM |
1775 WQ_HIGHPRI | WQ_FREEZABLE, 0);
1776 if (!glock_workqueue) {
1777 rhashtable_destroy(&gl_hash_table);
1778 return -ENOMEM;
1779 }
1780 gfs2_delete_workqueue = alloc_workqueue("delete_workqueue",
1781 WQ_MEM_RECLAIM | WQ_FREEZABLE,
1782 0);
1783 if (!gfs2_delete_workqueue) {
1784 destroy_workqueue(glock_workqueue);
1785 rhashtable_destroy(&gl_hash_table);
1786 return -ENOMEM;
1787 }
1788
1789 ret = register_shrinker(&glock_shrinker);
1790 if (ret) {
1791 destroy_workqueue(gfs2_delete_workqueue);
1792 destroy_workqueue(glock_workqueue);
1793 rhashtable_destroy(&gl_hash_table);
1794 return ret;
1795 }
1796
1797 return 0;
1798 }
1799
1800 void gfs2_glock_exit(void)
1801 {
1802 unregister_shrinker(&glock_shrinker);
1803 rhashtable_destroy(&gl_hash_table);
1804 destroy_workqueue(glock_workqueue);
1805 destroy_workqueue(gfs2_delete_workqueue);
1806 }
1807
1808 static void gfs2_glock_iter_next(struct gfs2_glock_iter *gi)
1809 {
1810 do {
1811 gi->gl = rhashtable_walk_next(&gi->hti);
1812 if (IS_ERR(gi->gl)) {
1813 if (PTR_ERR(gi->gl) == -EAGAIN)
1814 continue;
1815 gi->gl = NULL;
1816 }
1817 /* Skip entries for other sb and dead entries */
1818 } while ((gi->gl) && ((gi->sdp != gi->gl->gl_name.ln_sbd) ||
1819 __lockref_is_dead(&gi->gl->gl_lockref)));
1820 }
1821
1822 static void *gfs2_glock_seq_start(struct seq_file *seq, loff_t *pos)
1823 {
1824 struct gfs2_glock_iter *gi = seq->private;
1825 loff_t n = *pos;
1826 int ret;
1827
1828 if (gi->last_pos <= *pos)
1829 n = (*pos - gi->last_pos);
1830
1831 ret = rhashtable_walk_start(&gi->hti);
1832 if (ret)
1833 return NULL;
1834
1835 do {
1836 gfs2_glock_iter_next(gi);
1837 } while (gi->gl && n--);
1838
1839 gi->last_pos = *pos;
1840 return gi->gl;
1841 }
1842
1843 static void *gfs2_glock_seq_next(struct seq_file *seq, void *iter_ptr,
1844 loff_t *pos)
1845 {
1846 struct gfs2_glock_iter *gi = seq->private;
1847
1848 (*pos)++;
1849 gi->last_pos = *pos;
1850 gfs2_glock_iter_next(gi);
1851 return gi->gl;
1852 }
1853
1854 static void gfs2_glock_seq_stop(struct seq_file *seq, void *iter_ptr)
1855 {
1856 struct gfs2_glock_iter *gi = seq->private;
1857
1858 gi->gl = NULL;
1859 rhashtable_walk_stop(&gi->hti);
1860 }
1861
1862 static int gfs2_glock_seq_show(struct seq_file *seq, void *iter_ptr)
1863 {
1864 dump_glock(seq, iter_ptr);
1865 return 0;
1866 }
1867
1868 static void *gfs2_sbstats_seq_start(struct seq_file *seq, loff_t *pos)
1869 {
1870 preempt_disable();
1871 if (*pos >= GFS2_NR_SBSTATS)
1872 return NULL;
1873 return pos;
1874 }
1875
1876 static void *gfs2_sbstats_seq_next(struct seq_file *seq, void *iter_ptr,
1877 loff_t *pos)
1878 {
1879 (*pos)++;
1880 if (*pos >= GFS2_NR_SBSTATS)
1881 return NULL;
1882 return pos;
1883 }
1884
1885 static void gfs2_sbstats_seq_stop(struct seq_file *seq, void *iter_ptr)
1886 {
1887 preempt_enable();
1888 }
1889
1890 static const struct seq_operations gfs2_glock_seq_ops = {
1891 .start = gfs2_glock_seq_start,
1892 .next = gfs2_glock_seq_next,
1893 .stop = gfs2_glock_seq_stop,
1894 .show = gfs2_glock_seq_show,
1895 };
1896
1897 static const struct seq_operations gfs2_glstats_seq_ops = {
1898 .start = gfs2_glock_seq_start,
1899 .next = gfs2_glock_seq_next,
1900 .stop = gfs2_glock_seq_stop,
1901 .show = gfs2_glstats_seq_show,
1902 };
1903
1904 static const struct seq_operations gfs2_sbstats_seq_ops = {
1905 .start = gfs2_sbstats_seq_start,
1906 .next = gfs2_sbstats_seq_next,
1907 .stop = gfs2_sbstats_seq_stop,
1908 .show = gfs2_sbstats_seq_show,
1909 };
1910
1911 #define GFS2_SEQ_GOODSIZE min(PAGE_SIZE << PAGE_ALLOC_COSTLY_ORDER, 65536UL)
1912
1913 static int gfs2_glocks_open(struct inode *inode, struct file *file)
1914 {
1915 int ret = seq_open_private(file, &gfs2_glock_seq_ops,
1916 sizeof(struct gfs2_glock_iter));
1917 if (ret == 0) {
1918 struct seq_file *seq = file->private_data;
1919 struct gfs2_glock_iter *gi = seq->private;
1920
1921 gi->sdp = inode->i_private;
1922 gi->last_pos = 0;
1923 seq->buf = kmalloc(GFS2_SEQ_GOODSIZE, GFP_KERNEL | __GFP_NOWARN);
1924 if (seq->buf)
1925 seq->size = GFS2_SEQ_GOODSIZE;
1926 gi->gl = NULL;
1927 ret = rhashtable_walk_init(&gl_hash_table, &gi->hti, GFP_KERNEL);
1928 }
1929 return ret;
1930 }
1931
1932 static int gfs2_glocks_release(struct inode *inode, struct file *file)
1933 {
1934 struct seq_file *seq = file->private_data;
1935 struct gfs2_glock_iter *gi = seq->private;
1936
1937 gi->gl = NULL;
1938 rhashtable_walk_exit(&gi->hti);
1939 return seq_release_private(inode, file);
1940 }
1941
1942 static int gfs2_glstats_open(struct inode *inode, struct file *file)
1943 {
1944 int ret = seq_open_private(file, &gfs2_glstats_seq_ops,
1945 sizeof(struct gfs2_glock_iter));
1946 if (ret == 0) {
1947 struct seq_file *seq = file->private_data;
1948 struct gfs2_glock_iter *gi = seq->private;
1949 gi->sdp = inode->i_private;
1950 gi->last_pos = 0;
1951 seq->buf = kmalloc(GFS2_SEQ_GOODSIZE, GFP_KERNEL | __GFP_NOWARN);
1952 if (seq->buf)
1953 seq->size = GFS2_SEQ_GOODSIZE;
1954 gi->gl = NULL;
1955 ret = rhashtable_walk_init(&gl_hash_table, &gi->hti, GFP_KERNEL);
1956 }
1957 return ret;
1958 }
1959
1960 static int gfs2_sbstats_open(struct inode *inode, struct file *file)
1961 {
1962 int ret = seq_open(file, &gfs2_sbstats_seq_ops);
1963 if (ret == 0) {
1964 struct seq_file *seq = file->private_data;
1965 seq->private = inode->i_private; /* sdp */
1966 }
1967 return ret;
1968 }
1969
1970 static const struct file_operations gfs2_glocks_fops = {
1971 .owner = THIS_MODULE,
1972 .open = gfs2_glocks_open,
1973 .read = seq_read,
1974 .llseek = seq_lseek,
1975 .release = gfs2_glocks_release,
1976 };
1977
1978 static const struct file_operations gfs2_glstats_fops = {
1979 .owner = THIS_MODULE,
1980 .open = gfs2_glstats_open,
1981 .read = seq_read,
1982 .llseek = seq_lseek,
1983 .release = gfs2_glocks_release,
1984 };
1985
1986 static const struct file_operations gfs2_sbstats_fops = {
1987 .owner = THIS_MODULE,
1988 .open = gfs2_sbstats_open,
1989 .read = seq_read,
1990 .llseek = seq_lseek,
1991 .release = seq_release,
1992 };
1993
1994 int gfs2_create_debugfs_file(struct gfs2_sbd *sdp)
1995 {
1996 struct dentry *dent;
1997
1998 dent = debugfs_create_dir(sdp->sd_table_name, gfs2_root);
1999 if (IS_ERR_OR_NULL(dent))
2000 goto fail;
2001 sdp->debugfs_dir = dent;
2002
2003 dent = debugfs_create_file("glocks",
2004 S_IFREG | S_IRUGO,
2005 sdp->debugfs_dir, sdp,
2006 &gfs2_glocks_fops);
2007 if (IS_ERR_OR_NULL(dent))
2008 goto fail;
2009 sdp->debugfs_dentry_glocks = dent;
2010
2011 dent = debugfs_create_file("glstats",
2012 S_IFREG | S_IRUGO,
2013 sdp->debugfs_dir, sdp,
2014 &gfs2_glstats_fops);
2015 if (IS_ERR_OR_NULL(dent))
2016 goto fail;
2017 sdp->debugfs_dentry_glstats = dent;
2018
2019 dent = debugfs_create_file("sbstats",
2020 S_IFREG | S_IRUGO,
2021 sdp->debugfs_dir, sdp,
2022 &gfs2_sbstats_fops);
2023 if (IS_ERR_OR_NULL(dent))
2024 goto fail;
2025 sdp->debugfs_dentry_sbstats = dent;
2026
2027 return 0;
2028 fail:
2029 gfs2_delete_debugfs_file(sdp);
2030 return dent ? PTR_ERR(dent) : -ENOMEM;
2031 }
2032
2033 void gfs2_delete_debugfs_file(struct gfs2_sbd *sdp)
2034 {
2035 if (sdp->debugfs_dir) {
2036 if (sdp->debugfs_dentry_glocks) {
2037 debugfs_remove(sdp->debugfs_dentry_glocks);
2038 sdp->debugfs_dentry_glocks = NULL;
2039 }
2040 if (sdp->debugfs_dentry_glstats) {
2041 debugfs_remove(sdp->debugfs_dentry_glstats);
2042 sdp->debugfs_dentry_glstats = NULL;
2043 }
2044 if (sdp->debugfs_dentry_sbstats) {
2045 debugfs_remove(sdp->debugfs_dentry_sbstats);
2046 sdp->debugfs_dentry_sbstats = NULL;
2047 }
2048 debugfs_remove(sdp->debugfs_dir);
2049 sdp->debugfs_dir = NULL;
2050 }
2051 }
2052
2053 int gfs2_register_debugfs(void)
2054 {
2055 gfs2_root = debugfs_create_dir("gfs2", NULL);
2056 if (IS_ERR(gfs2_root))
2057 return PTR_ERR(gfs2_root);
2058 return gfs2_root ? 0 : -ENOMEM;
2059 }
2060
2061 void gfs2_unregister_debugfs(void)
2062 {
2063 debugfs_remove(gfs2_root);
2064 gfs2_root = NULL;
2065 }
Linux with added FPC-III support