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mtd: bcm47xxnflash: init NAND on BCM4706
[linux-2.6/btrfs-unstable.git] / fs / gfs2 / glock.c
blobe6c2fd53cab252da56fab66b3ca2749ef7ed1f44
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 #include <linux/sched.h>
11 #include <linux/slab.h>
12 #include <linux/spinlock.h>
13 #include <linux/buffer_head.h>
14 #include <linux/delay.h>
15 #include <linux/sort.h>
16 #include <linux/jhash.h>
17 #include <linux/kallsyms.h>
18 #include <linux/gfs2_ondisk.h>
19 #include <linux/list.h>
20 #include <linux/wait.h>
21 #include <linux/module.h>
22 #include <asm/uaccess.h>
23 #include <linux/seq_file.h>
24 #include <linux/debugfs.h>
25 #include <linux/kthread.h>
26 #include <linux/freezer.h>
27 #include <linux/workqueue.h>
28 #include <linux/jiffies.h>
29 #include <linux/rcupdate.h>
30 #include <linux/rculist_bl.h>
31 #include <linux/bit_spinlock.h>
32 #include <linux/percpu.h>
33
34 #include "gfs2.h"
35 #include "incore.h"
36 #include "glock.h"
37 #include "glops.h"
38 #include "inode.h"
39 #include "lops.h"
40 #include "meta_io.h"
41 #include "quota.h"
42 #include "super.h"
43 #include "util.h"
44 #include "bmap.h"
45 #define CREATE_TRACE_POINTS
46 #include "trace_gfs2.h"
47
48 struct gfs2_glock_iter {
49 int hash; /* hash bucket index */
50 unsigned nhash; /* Index within current bucket */
51 struct gfs2_sbd *sdp; /* incore superblock */
52 struct gfs2_glock *gl; /* current glock struct */
53 loff_t last_pos; /* last position */
54 };
55
56 typedef void (*glock_examiner) (struct gfs2_glock * gl);
57
58 static int __dump_glock(struct seq_file *seq, const struct gfs2_glock *gl);
59 #define GLOCK_BUG_ON(gl,x) do { if (unlikely(x)) { __dump_glock(NULL, gl); BUG(); } } while(0)
60 static void do_xmote(struct gfs2_glock *gl, struct gfs2_holder *gh, unsigned int target);
61
62 static struct dentry *gfs2_root;
63 static struct workqueue_struct *glock_workqueue;
64 struct workqueue_struct *gfs2_delete_workqueue;
65 static LIST_HEAD(lru_list);
66 static atomic_t lru_count = ATOMIC_INIT(0);
67 static DEFINE_SPINLOCK(lru_lock);
68
69 #define GFS2_GL_HASH_SHIFT 15
70 #define GFS2_GL_HASH_SIZE (1 << GFS2_GL_HASH_SHIFT)
71 #define GFS2_GL_HASH_MASK (GFS2_GL_HASH_SIZE - 1)
72
73 static struct hlist_bl_head gl_hash_table[GFS2_GL_HASH_SIZE];
74 static struct dentry *gfs2_root;
75
76 /**
77 * gl_hash() - Turn glock number into hash bucket number
78 * @lock: The glock number
79 *
80 * Returns: The number of the corresponding hash bucket
81 */
82
83 static unsigned int gl_hash(const struct gfs2_sbd *sdp,
84 const struct lm_lockname *name)
85 {
86 unsigned int h;
87
88 h = jhash(&name->ln_number, sizeof(u64), 0);
89 h = jhash(&name->ln_type, sizeof(unsigned int), h);
90 h = jhash(&sdp, sizeof(struct gfs2_sbd *), h);
91 h &= GFS2_GL_HASH_MASK;
92
93 return h;
94 }
95
96 static inline void spin_lock_bucket(unsigned int hash)
97 {
98 hlist_bl_lock(&gl_hash_table[hash]);
99 }
100
101 static inline void spin_unlock_bucket(unsigned int hash)
102 {
103 hlist_bl_unlock(&gl_hash_table[hash]);
104 }
105
106 static void gfs2_glock_dealloc(struct rcu_head *rcu)
107 {
108 struct gfs2_glock *gl = container_of(rcu, struct gfs2_glock, gl_rcu);
109
110 if (gl->gl_ops->go_flags & GLOF_ASPACE)
111 kmem_cache_free(gfs2_glock_aspace_cachep, gl);
112 else
113 kmem_cache_free(gfs2_glock_cachep, gl);
114 }
115
116 void gfs2_glock_free(struct gfs2_glock *gl)
117 {
118 struct gfs2_sbd *sdp = gl->gl_sbd;
119
120 call_rcu(&gl->gl_rcu, gfs2_glock_dealloc);
121 if (atomic_dec_and_test(&sdp->sd_glock_disposal))
122 wake_up(&sdp->sd_glock_wait);
123 }
124
125 /**
126 * gfs2_glock_hold() - increment reference count on glock
127 * @gl: The glock to hold
128 *
129 */
130
131 void gfs2_glock_hold(struct gfs2_glock *gl)
132 {
133 GLOCK_BUG_ON(gl, atomic_read(&gl->gl_ref) == 0);
134 atomic_inc(&gl->gl_ref);
135 }
136
137 /**
138 * demote_ok - Check to see if it's ok to unlock a glock
139 * @gl: the glock
140 *
141 * Returns: 1 if it's ok
142 */
143
144 static int demote_ok(const struct gfs2_glock *gl)
145 {
146 const struct gfs2_glock_operations *glops = gl->gl_ops;
147
148 if (gl->gl_state == LM_ST_UNLOCKED)
149 return 0;
150 if (!list_empty(&gl->gl_holders))
151 return 0;
152 if (glops->go_demote_ok)
153 return glops->go_demote_ok(gl);
154 return 1;
155 }
156
157
158 void gfs2_glock_add_to_lru(struct gfs2_glock *gl)
159 {
160 spin_lock(&lru_lock);
161
162 if (!list_empty(&gl->gl_lru))
163 list_del_init(&gl->gl_lru);
164 else
165 atomic_inc(&lru_count);
166
167 list_add_tail(&gl->gl_lru, &lru_list);
168 set_bit(GLF_LRU, &gl->gl_flags);
169 spin_unlock(&lru_lock);
170 }
171
172 static void __gfs2_glock_remove_from_lru(struct gfs2_glock *gl)
173 {
174 if (!list_empty(&gl->gl_lru)) {
175 list_del_init(&gl->gl_lru);
176 atomic_dec(&lru_count);
177 clear_bit(GLF_LRU, &gl->gl_flags);
178 }
179 }
180
181 static void gfs2_glock_remove_from_lru(struct gfs2_glock *gl)
182 {
183 spin_lock(&lru_lock);
184 __gfs2_glock_remove_from_lru(gl);
185 spin_unlock(&lru_lock);
186 }
187
188 /**
189 * gfs2_glock_put_nolock() - Decrement reference count on glock
190 * @gl: The glock to put
191 *
192 * This function should only be used if the caller has its own reference
193 * to the glock, in addition to the one it is dropping.
194 */
195
196 void gfs2_glock_put_nolock(struct gfs2_glock *gl)
197 {
198 if (atomic_dec_and_test(&gl->gl_ref))
199 GLOCK_BUG_ON(gl, 1);
200 }
201
202 /**
203 * gfs2_glock_put() - Decrement reference count on glock
204 * @gl: The glock to put
205 *
206 */
207
208 void gfs2_glock_put(struct gfs2_glock *gl)
209 {
210 struct gfs2_sbd *sdp = gl->gl_sbd;
211 struct address_space *mapping = gfs2_glock2aspace(gl);
212
213 if (atomic_dec_and_lock(&gl->gl_ref, &lru_lock)) {
214 __gfs2_glock_remove_from_lru(gl);
215 spin_unlock(&lru_lock);
216 spin_lock_bucket(gl->gl_hash);
217 hlist_bl_del_rcu(&gl->gl_list);
218 spin_unlock_bucket(gl->gl_hash);
219 GLOCK_BUG_ON(gl, !list_empty(&gl->gl_holders));
220 GLOCK_BUG_ON(gl, mapping && mapping->nrpages);
221 trace_gfs2_glock_put(gl);
222 sdp->sd_lockstruct.ls_ops->lm_put_lock(gl);
223 }
224 }
225
226 /**
227 * search_bucket() - Find struct gfs2_glock by lock number
228 * @bucket: the bucket to search
229 * @name: The lock name
230 *
231 * Returns: NULL, or the struct gfs2_glock with the requested number
232 */
233
234 static struct gfs2_glock *search_bucket(unsigned int hash,
235 const struct gfs2_sbd *sdp,
236 const struct lm_lockname *name)
237 {
238 struct gfs2_glock *gl;
239 struct hlist_bl_node *h;
240
241 hlist_bl_for_each_entry_rcu(gl, h, &gl_hash_table[hash], gl_list) {
242 if (!lm_name_equal(&gl->gl_name, name))
243 continue;
244 if (gl->gl_sbd != sdp)
245 continue;
246 if (atomic_inc_not_zero(&gl->gl_ref))
247 return gl;
248 }
249
250 return NULL;
251 }
252
253 /**
254 * may_grant - check if its ok to grant a new lock
255 * @gl: The glock
256 * @gh: The lock request which we wish to grant
257 *
258 * Returns: true if its ok to grant the lock
259 */
260
261 static inline int may_grant(const struct gfs2_glock *gl, const struct gfs2_holder *gh)
262 {
263 const struct gfs2_holder *gh_head = list_entry(gl->gl_holders.next, const struct gfs2_holder, gh_list);
264 if ((gh->gh_state == LM_ST_EXCLUSIVE ||
265 gh_head->gh_state == LM_ST_EXCLUSIVE) && gh != gh_head)
266 return 0;
267 if (gl->gl_state == gh->gh_state)
268 return 1;
269 if (gh->gh_flags & GL_EXACT)
270 return 0;
271 if (gl->gl_state == LM_ST_EXCLUSIVE) {
272 if (gh->gh_state == LM_ST_SHARED && gh_head->gh_state == LM_ST_SHARED)
273 return 1;
274 if (gh->gh_state == LM_ST_DEFERRED && gh_head->gh_state == LM_ST_DEFERRED)
275 return 1;
276 }
277 if (gl->gl_state != LM_ST_UNLOCKED && (gh->gh_flags & LM_FLAG_ANY))
278 return 1;
279 return 0;
280 }
281
282 static void gfs2_holder_wake(struct gfs2_holder *gh)
283 {
284 clear_bit(HIF_WAIT, &gh->gh_iflags);
285 smp_mb__after_clear_bit();
286 wake_up_bit(&gh->gh_iflags, HIF_WAIT);
287 }
288
289 /**
290 * do_error - Something unexpected has happened during a lock request
291 *
292 */
293
294 static inline void do_error(struct gfs2_glock *gl, const int ret)
295 {
296 struct gfs2_holder *gh, *tmp;
297
298 list_for_each_entry_safe(gh, tmp, &gl->gl_holders, gh_list) {
299 if (test_bit(HIF_HOLDER, &gh->gh_iflags))
300 continue;
301 if (ret & LM_OUT_ERROR)
302 gh->gh_error = -EIO;
303 else if (gh->gh_flags & (LM_FLAG_TRY | LM_FLAG_TRY_1CB))
304 gh->gh_error = GLR_TRYFAILED;
305 else
306 continue;
307 list_del_init(&gh->gh_list);
308 trace_gfs2_glock_queue(gh, 0);
309 gfs2_holder_wake(gh);
310 }
311 }
312
313 /**
314 * do_promote - promote as many requests as possible on the current queue
315 * @gl: The glock
316 *
317 * Returns: 1 if there is a blocked holder at the head of the list, or 2
318 * if a type specific operation is underway.
319 */
320
321 static int do_promote(struct gfs2_glock *gl)
322 __releases(&gl->gl_spin)
323 __acquires(&gl->gl_spin)
324 {
325 const struct gfs2_glock_operations *glops = gl->gl_ops;
326 struct gfs2_holder *gh, *tmp;
327 int ret;
328
329 restart:
330 list_for_each_entry_safe(gh, tmp, &gl->gl_holders, gh_list) {
331 if (test_bit(HIF_HOLDER, &gh->gh_iflags))
332 continue;
333 if (may_grant(gl, gh)) {
334 if (gh->gh_list.prev == &gl->gl_holders &&
335 glops->go_lock) {
336 spin_unlock(&gl->gl_spin);
337 /* FIXME: eliminate this eventually */
338 ret = glops->go_lock(gh);
339 spin_lock(&gl->gl_spin);
340 if (ret) {
341 if (ret == 1)
342 return 2;
343 gh->gh_error = ret;
344 list_del_init(&gh->gh_list);
345 trace_gfs2_glock_queue(gh, 0);
346 gfs2_holder_wake(gh);
347 goto restart;
348 }
349 set_bit(HIF_HOLDER, &gh->gh_iflags);
350 trace_gfs2_promote(gh, 1);
351 gfs2_holder_wake(gh);
352 goto restart;
353 }
354 set_bit(HIF_HOLDER, &gh->gh_iflags);
355 trace_gfs2_promote(gh, 0);
356 gfs2_holder_wake(gh);
357 continue;
358 }
359 if (gh->gh_list.prev == &gl->gl_holders)
360 return 1;
361 do_error(gl, 0);
362 break;
363 }
364 return 0;
365 }
366
367 /**
368 * find_first_waiter - find the first gh that's waiting for the glock
369 * @gl: the glock
370 */
371
372 static inline struct gfs2_holder *find_first_waiter(const struct gfs2_glock *gl)
373 {
374 struct gfs2_holder *gh;
375
376 list_for_each_entry(gh, &gl->gl_holders, gh_list) {
377 if (!test_bit(HIF_HOLDER, &gh->gh_iflags))
378 return gh;
379 }
380 return NULL;
381 }
382
383 /**
384 * state_change - record that the glock is now in a different state
385 * @gl: the glock
386 * @new_state the new state
387 *
388 */
389
390 static void state_change(struct gfs2_glock *gl, unsigned int new_state)
391 {
392 int held1, held2;
393
394 held1 = (gl->gl_state != LM_ST_UNLOCKED);
395 held2 = (new_state != LM_ST_UNLOCKED);
396
397 if (held1 != held2) {
398 if (held2)
399 gfs2_glock_hold(gl);
400 else
401 gfs2_glock_put_nolock(gl);
402 }
403 if (held1 && held2 && list_empty(&gl->gl_holders))
404 clear_bit(GLF_QUEUED, &gl->gl_flags);
405
406 if (new_state != gl->gl_target)
407 /* shorten our minimum hold time */
408 gl->gl_hold_time = max(gl->gl_hold_time - GL_GLOCK_HOLD_DECR,
409 GL_GLOCK_MIN_HOLD);
410 gl->gl_state = new_state;
411 gl->gl_tchange = jiffies;
412 }
413
414 static void gfs2_demote_wake(struct gfs2_glock *gl)
415 {
416 gl->gl_demote_state = LM_ST_EXCLUSIVE;
417 clear_bit(GLF_DEMOTE, &gl->gl_flags);
418 smp_mb__after_clear_bit();
419 wake_up_bit(&gl->gl_flags, GLF_DEMOTE);
420 }
421
422 /**
423 * finish_xmote - The DLM has replied to one of our lock requests
424 * @gl: The glock
425 * @ret: The status from the DLM
426 *
427 */
428
429 static void finish_xmote(struct gfs2_glock *gl, unsigned int ret)
430 {
431 const struct gfs2_glock_operations *glops = gl->gl_ops;
432 struct gfs2_holder *gh;
433 unsigned state = ret & LM_OUT_ST_MASK;
434 int rv;
435
436 spin_lock(&gl->gl_spin);
437 trace_gfs2_glock_state_change(gl, state);
438 state_change(gl, state);
439 gh = find_first_waiter(gl);
440
441 /* Demote to UN request arrived during demote to SH or DF */
442 if (test_bit(GLF_DEMOTE_IN_PROGRESS, &gl->gl_flags) &&
443 state != LM_ST_UNLOCKED && gl->gl_demote_state == LM_ST_UNLOCKED)
444 gl->gl_target = LM_ST_UNLOCKED;
445
446 /* Check for state != intended state */
447 if (unlikely(state != gl->gl_target)) {
448 if (gh && !test_bit(GLF_DEMOTE_IN_PROGRESS, &gl->gl_flags)) {
449 /* move to back of queue and try next entry */
450 if (ret & LM_OUT_CANCELED) {
451 if ((gh->gh_flags & LM_FLAG_PRIORITY) == 0)
452 list_move_tail(&gh->gh_list, &gl->gl_holders);
453 gh = find_first_waiter(gl);
454 gl->gl_target = gh->gh_state;
455 goto retry;
456 }
457 /* Some error or failed "try lock" - report it */
458 if ((ret & LM_OUT_ERROR) ||
459 (gh->gh_flags & (LM_FLAG_TRY | LM_FLAG_TRY_1CB))) {
460 gl->gl_target = gl->gl_state;
461 do_error(gl, ret);
462 goto out;
463 }
464 }
465 switch(state) {
466 /* Unlocked due to conversion deadlock, try again */
467 case LM_ST_UNLOCKED:
468 retry:
469 do_xmote(gl, gh, gl->gl_target);
470 break;
471 /* Conversion fails, unlock and try again */
472 case LM_ST_SHARED:
473 case LM_ST_DEFERRED:
474 do_xmote(gl, gh, LM_ST_UNLOCKED);
475 break;
476 default: /* Everything else */
477 printk(KERN_ERR "GFS2: wanted %u got %u\n", gl->gl_target, state);
478 GLOCK_BUG_ON(gl, 1);
479 }
480 spin_unlock(&gl->gl_spin);
481 return;
482 }
483
484 /* Fast path - we got what we asked for */
485 if (test_and_clear_bit(GLF_DEMOTE_IN_PROGRESS, &gl->gl_flags))
486 gfs2_demote_wake(gl);
487 if (state != LM_ST_UNLOCKED) {
488 if (glops->go_xmote_bh) {
489 spin_unlock(&gl->gl_spin);
490 rv = glops->go_xmote_bh(gl, gh);
491 spin_lock(&gl->gl_spin);
492 if (rv) {
493 do_error(gl, rv);
494 goto out;
495 }
496 }
497 rv = do_promote(gl);
498 if (rv == 2)
499 goto out_locked;
500 }
501 out:
502 clear_bit(GLF_LOCK, &gl->gl_flags);
503 out_locked:
504 spin_unlock(&gl->gl_spin);
505 }
506
507 /**
508 * do_xmote - Calls the DLM to change the state of a lock
509 * @gl: The lock state
510 * @gh: The holder (only for promotes)
511 * @target: The target lock state
512 *
513 */
514
515 static void do_xmote(struct gfs2_glock *gl, struct gfs2_holder *gh, unsigned int target)
516 __releases(&gl->gl_spin)
517 __acquires(&gl->gl_spin)
518 {
519 const struct gfs2_glock_operations *glops = gl->gl_ops;
520 struct gfs2_sbd *sdp = gl->gl_sbd;
521 unsigned int lck_flags = gh ? gh->gh_flags : 0;
522 int ret;
523
524 lck_flags &= (LM_FLAG_TRY | LM_FLAG_TRY_1CB | LM_FLAG_NOEXP |
525 LM_FLAG_PRIORITY);
526 GLOCK_BUG_ON(gl, gl->gl_state == target);
527 GLOCK_BUG_ON(gl, gl->gl_state == gl->gl_target);
528 if ((target == LM_ST_UNLOCKED || target == LM_ST_DEFERRED) &&
529 glops->go_inval) {
530 set_bit(GLF_INVALIDATE_IN_PROGRESS, &gl->gl_flags);
531 do_error(gl, 0); /* Fail queued try locks */
532 }
533 gl->gl_req = target;
534 set_bit(GLF_BLOCKING, &gl->gl_flags);
535 if ((gl->gl_req == LM_ST_UNLOCKED) ||
536 (gl->gl_state == LM_ST_EXCLUSIVE) ||
537 (lck_flags & (LM_FLAG_TRY|LM_FLAG_TRY_1CB)))
538 clear_bit(GLF_BLOCKING, &gl->gl_flags);
539 spin_unlock(&gl->gl_spin);
540 if (glops->go_xmote_th)
541 glops->go_xmote_th(gl);
542 if (test_bit(GLF_INVALIDATE_IN_PROGRESS, &gl->gl_flags))
543 glops->go_inval(gl, target == LM_ST_DEFERRED ? 0 : DIO_METADATA);
544 clear_bit(GLF_INVALIDATE_IN_PROGRESS, &gl->gl_flags);
545
546 gfs2_glock_hold(gl);
547 if (sdp->sd_lockstruct.ls_ops->lm_lock) {
548 /* lock_dlm */
549 ret = sdp->sd_lockstruct.ls_ops->lm_lock(gl, target, lck_flags);
550 GLOCK_BUG_ON(gl, ret);
551 } else { /* lock_nolock */
552 finish_xmote(gl, target);
553 if (queue_delayed_work(glock_workqueue, &gl->gl_work, 0) == 0)
554 gfs2_glock_put(gl);
555 }
556
557 spin_lock(&gl->gl_spin);
558 }
559
560 /**
561 * find_first_holder - find the first "holder" gh
562 * @gl: the glock
563 */
564
565 static inline struct gfs2_holder *find_first_holder(const struct gfs2_glock *gl)
566 {
567 struct gfs2_holder *gh;
568
569 if (!list_empty(&gl->gl_holders)) {
570 gh = list_entry(gl->gl_holders.next, struct gfs2_holder, gh_list);
571 if (test_bit(HIF_HOLDER, &gh->gh_iflags))
572 return gh;
573 }
574 return NULL;
575 }
576
577 /**
578 * run_queue - do all outstanding tasks related to a glock
579 * @gl: The glock in question
580 * @nonblock: True if we must not block in run_queue
581 *
582 */
583
584 static void run_queue(struct gfs2_glock *gl, const int nonblock)
585 __releases(&gl->gl_spin)
586 __acquires(&gl->gl_spin)
587 {
588 struct gfs2_holder *gh = NULL;
589 int ret;
590
591 if (test_and_set_bit(GLF_LOCK, &gl->gl_flags))
592 return;
593
594 GLOCK_BUG_ON(gl, test_bit(GLF_DEMOTE_IN_PROGRESS, &gl->gl_flags));
595
596 if (test_bit(GLF_DEMOTE, &gl->gl_flags) &&
597 gl->gl_demote_state != gl->gl_state) {
598 if (find_first_holder(gl))
599 goto out_unlock;
600 if (nonblock)
601 goto out_sched;
602 set_bit(GLF_DEMOTE_IN_PROGRESS, &gl->gl_flags);
603 GLOCK_BUG_ON(gl, gl->gl_demote_state == LM_ST_EXCLUSIVE);
604 gl->gl_target = gl->gl_demote_state;
605 } else {
606 if (test_bit(GLF_DEMOTE, &gl->gl_flags))
607 gfs2_demote_wake(gl);
608 ret = do_promote(gl);
609 if (ret == 0)
610 goto out_unlock;
611 if (ret == 2)
612 goto out;
613 gh = find_first_waiter(gl);
614 gl->gl_target = gh->gh_state;
615 if (!(gh->gh_flags & (LM_FLAG_TRY | LM_FLAG_TRY_1CB)))
616 do_error(gl, 0); /* Fail queued try locks */
617 }
618 do_xmote(gl, gh, gl->gl_target);
619 out:
620 return;
621
622 out_sched:
623 clear_bit(GLF_LOCK, &gl->gl_flags);
624 smp_mb__after_clear_bit();
625 gfs2_glock_hold(gl);
626 if (queue_delayed_work(glock_workqueue, &gl->gl_work, 0) == 0)
627 gfs2_glock_put_nolock(gl);
628 return;
629
630 out_unlock:
631 clear_bit(GLF_LOCK, &gl->gl_flags);
632 smp_mb__after_clear_bit();
633 return;
634 }
635
636 static void delete_work_func(struct work_struct *work)
637 {
638 struct gfs2_glock *gl = container_of(work, struct gfs2_glock, gl_delete);
639 struct gfs2_sbd *sdp = gl->gl_sbd;
640 struct gfs2_inode *ip;
641 struct inode *inode;
642 u64 no_addr = gl->gl_name.ln_number;
643
644 ip = gl->gl_object;
645 /* Note: Unsafe to dereference ip as we don't hold right refs/locks */
646
647 if (ip)
648 inode = gfs2_ilookup(sdp->sd_vfs, no_addr, 1);
649 else
650 inode = gfs2_lookup_by_inum(sdp, no_addr, NULL, GFS2_BLKST_UNLINKED);
651 if (inode && !IS_ERR(inode)) {
652 d_prune_aliases(inode);
653 iput(inode);
654 }
655 gfs2_glock_put(gl);
656 }
657
658 static void glock_work_func(struct work_struct *work)
659 {
660 unsigned long delay = 0;
661 struct gfs2_glock *gl = container_of(work, struct gfs2_glock, gl_work.work);
662 int drop_ref = 0;
663
664 if (test_and_clear_bit(GLF_REPLY_PENDING, &gl->gl_flags)) {
665 finish_xmote(gl, gl->gl_reply);
666 drop_ref = 1;
667 }
668 spin_lock(&gl->gl_spin);
669 if (test_bit(GLF_PENDING_DEMOTE, &gl->gl_flags) &&
670 gl->gl_state != LM_ST_UNLOCKED &&
671 gl->gl_demote_state != LM_ST_EXCLUSIVE) {
672 unsigned long holdtime, now = jiffies;
673
674 holdtime = gl->gl_tchange + gl->gl_hold_time;
675 if (time_before(now, holdtime))
676 delay = holdtime - now;
677
678 if (!delay) {
679 clear_bit(GLF_PENDING_DEMOTE, &gl->gl_flags);
680 set_bit(GLF_DEMOTE, &gl->gl_flags);
681 }
682 }
683 run_queue(gl, 0);
684 spin_unlock(&gl->gl_spin);
685 if (!delay)
686 gfs2_glock_put(gl);
687 else {
688 if (gl->gl_name.ln_type != LM_TYPE_INODE)
689 delay = 0;
690 if (queue_delayed_work(glock_workqueue, &gl->gl_work, delay) == 0)
691 gfs2_glock_put(gl);
692 }
693 if (drop_ref)
694 gfs2_glock_put(gl);
695 }
696
697 /**
698 * gfs2_glock_get() - Get a glock, or create one if one doesn't exist
699 * @sdp: The GFS2 superblock
700 * @number: the lock number
701 * @glops: The glock_operations to use
702 * @create: If 0, don't create the glock if it doesn't exist
703 * @glp: the glock is returned here
704 *
705 * This does not lock a glock, just finds/creates structures for one.
706 *
707 * Returns: errno
708 */
709
710 int gfs2_glock_get(struct gfs2_sbd *sdp, u64 number,
711 const struct gfs2_glock_operations *glops, int create,
712 struct gfs2_glock **glp)
713 {
714 struct super_block *s = sdp->sd_vfs;
715 struct lm_lockname name = { .ln_number = number, .ln_type = glops->go_type };
716 struct gfs2_glock *gl, *tmp;
717 unsigned int hash = gl_hash(sdp, &name);
718 struct address_space *mapping;
719 struct kmem_cache *cachep;
720
721 rcu_read_lock();
722 gl = search_bucket(hash, sdp, &name);
723 rcu_read_unlock();
724
725 *glp = gl;
726 if (gl)
727 return 0;
728 if (!create)
729 return -ENOENT;
730
731 if (glops->go_flags & GLOF_ASPACE)
732 cachep = gfs2_glock_aspace_cachep;
733 else
734 cachep = gfs2_glock_cachep;
735 gl = kmem_cache_alloc(cachep, GFP_KERNEL);
736 if (!gl)
737 return -ENOMEM;
738
739 atomic_inc(&sdp->sd_glock_disposal);
740 gl->gl_sbd = sdp;
741 gl->gl_flags = 0;
742 gl->gl_name = name;
743 atomic_set(&gl->gl_ref, 1);
744 gl->gl_state = LM_ST_UNLOCKED;
745 gl->gl_target = LM_ST_UNLOCKED;
746 gl->gl_demote_state = LM_ST_EXCLUSIVE;
747 gl->gl_hash = hash;
748 gl->gl_ops = glops;
749 gl->gl_dstamp = ktime_set(0, 0);
750 preempt_disable();
751 /* We use the global stats to estimate the initial per-glock stats */
752 gl->gl_stats = this_cpu_ptr(sdp->sd_lkstats)->lkstats[glops->go_type];
753 preempt_enable();
754 gl->gl_stats.stats[GFS2_LKS_DCOUNT] = 0;
755 gl->gl_stats.stats[GFS2_LKS_QCOUNT] = 0;
756 memset(&gl->gl_lksb, 0, sizeof(struct dlm_lksb));
757 memset(gl->gl_lvb, 0, 32 * sizeof(char));
758 gl->gl_lksb.sb_lvbptr = gl->gl_lvb;
759 gl->gl_tchange = jiffies;
760 gl->gl_object = NULL;
761 gl->gl_hold_time = GL_GLOCK_DFT_HOLD;
762 INIT_DELAYED_WORK(&gl->gl_work, glock_work_func);
763 INIT_WORK(&gl->gl_delete, delete_work_func);
764
765 mapping = gfs2_glock2aspace(gl);
766 if (mapping) {
767 mapping->a_ops = &gfs2_meta_aops;
768 mapping->host = s->s_bdev->bd_inode;
769 mapping->flags = 0;
770 mapping_set_gfp_mask(mapping, GFP_NOFS);
771 mapping->assoc_mapping = NULL;
772 mapping->backing_dev_info = s->s_bdi;
773 mapping->writeback_index = 0;
774 }
775
776 spin_lock_bucket(hash);
777 tmp = search_bucket(hash, sdp, &name);
778 if (tmp) {
779 spin_unlock_bucket(hash);
780 kmem_cache_free(cachep, gl);
781 atomic_dec(&sdp->sd_glock_disposal);
782 gl = tmp;
783 } else {
784 hlist_bl_add_head_rcu(&gl->gl_list, &gl_hash_table[hash]);
785 spin_unlock_bucket(hash);
786 }
787
788 *glp = gl;
789
790 return 0;
791 }
792
793 /**
794 * gfs2_holder_init - initialize a struct gfs2_holder in the default way
795 * @gl: the glock
796 * @state: the state we're requesting
797 * @flags: the modifier flags
798 * @gh: the holder structure
799 *
800 */
801
802 void gfs2_holder_init(struct gfs2_glock *gl, unsigned int state, unsigned flags,
803 struct gfs2_holder *gh)
804 {
805 INIT_LIST_HEAD(&gh->gh_list);
806 gh->gh_gl = gl;
807 gh->gh_ip = (unsigned long)__builtin_return_address(0);
808 gh->gh_owner_pid = get_pid(task_pid(current));
809 gh->gh_state = state;
810 gh->gh_flags = flags;
811 gh->gh_error = 0;
812 gh->gh_iflags = 0;
813 gfs2_glock_hold(gl);
814 }
815
816 /**
817 * gfs2_holder_reinit - reinitialize a struct gfs2_holder so we can requeue it
818 * @state: the state we're requesting
819 * @flags: the modifier flags
820 * @gh: the holder structure
821 *
822 * Don't mess with the glock.
823 *
824 */
825
826 void gfs2_holder_reinit(unsigned int state, unsigned flags, struct gfs2_holder *gh)
827 {
828 gh->gh_state = state;
829 gh->gh_flags = flags;
830 gh->gh_iflags = 0;
831 gh->gh_ip = (unsigned long)__builtin_return_address(0);
832 if (gh->gh_owner_pid)
833 put_pid(gh->gh_owner_pid);
834 gh->gh_owner_pid = get_pid(task_pid(current));
835 }
836
837 /**
838 * gfs2_holder_uninit - uninitialize a holder structure (drop glock reference)
839 * @gh: the holder structure
840 *
841 */
842
843 void gfs2_holder_uninit(struct gfs2_holder *gh)
844 {
845 put_pid(gh->gh_owner_pid);
846 gfs2_glock_put(gh->gh_gl);
847 gh->gh_gl = NULL;
848 gh->gh_ip = 0;
849 }
850
851 /**
852 * gfs2_glock_holder_wait
853 * @word: unused
854 *
855 * This function and gfs2_glock_demote_wait both show up in the WCHAN
856 * field. Thus I've separated these otherwise identical functions in
857 * order to be more informative to the user.
858 */
859
860 static int gfs2_glock_holder_wait(void *word)
861 {
862 schedule();
863 return 0;
864 }
865
866 static int gfs2_glock_demote_wait(void *word)
867 {
868 schedule();
869 return 0;
870 }
871
872 /**
873 * gfs2_glock_wait - wait on a glock acquisition
874 * @gh: the glock holder
875 *
876 * Returns: 0 on success
877 */
878
879 int gfs2_glock_wait(struct gfs2_holder *gh)
880 {
881 unsigned long time1 = jiffies;
882
883 might_sleep();
884 wait_on_bit(&gh->gh_iflags, HIF_WAIT, gfs2_glock_holder_wait, TASK_UNINTERRUPTIBLE);
885 if (time_after(jiffies, time1 + HZ)) /* have we waited > a second? */
886 /* Lengthen the minimum hold time. */
887 gh->gh_gl->gl_hold_time = min(gh->gh_gl->gl_hold_time +
888 GL_GLOCK_HOLD_INCR,
889 GL_GLOCK_MAX_HOLD);
890 return gh->gh_error;
891 }
892
893 /**
894 * handle_callback - process a demote request
895 * @gl: the glock
896 * @state: the state the caller wants us to change to
897 *
898 * There are only two requests that we are going to see in actual
899 * practise: LM_ST_SHARED and LM_ST_UNLOCKED
900 */
901
902 static void handle_callback(struct gfs2_glock *gl, unsigned int state,
903 unsigned long delay)
904 {
905 int bit = delay ? GLF_PENDING_DEMOTE : GLF_DEMOTE;
906
907 set_bit(bit, &gl->gl_flags);
908 if (gl->gl_demote_state == LM_ST_EXCLUSIVE) {
909 gl->gl_demote_state = state;
910 gl->gl_demote_time = jiffies;
911 } else if (gl->gl_demote_state != LM_ST_UNLOCKED &&
912 gl->gl_demote_state != state) {
913 gl->gl_demote_state = LM_ST_UNLOCKED;
914 }
915 if (gl->gl_ops->go_callback)
916 gl->gl_ops->go_callback(gl);
917 trace_gfs2_demote_rq(gl);
918 }
919
920 void gfs2_print_dbg(struct seq_file *seq, const char *fmt, ...)
921 {
922 struct va_format vaf;
923 va_list args;
924
925 va_start(args, fmt);
926
927 if (seq) {
928 seq_vprintf(seq, fmt, args);
929 } else {
930 vaf.fmt = fmt;
931 vaf.va = &args;
932
933 printk(KERN_ERR " %pV", &vaf);
934 }
935
936 va_end(args);
937 }
938
939 /**
940 * add_to_queue - Add a holder to the wait queue (but look for recursion)
941 * @gh: the holder structure to add
942 *
943 * Eventually we should move the recursive locking trap to a
944 * debugging option or something like that. This is the fast
945 * path and needs to have the minimum number of distractions.
946 *
947 */
948
949 static inline void add_to_queue(struct gfs2_holder *gh)
950 __releases(&gl->gl_spin)
951 __acquires(&gl->gl_spin)
952 {
953 struct gfs2_glock *gl = gh->gh_gl;
954 struct gfs2_sbd *sdp = gl->gl_sbd;
955 struct list_head *insert_pt = NULL;
956 struct gfs2_holder *gh2;
957 int try_futile = 0;
958
959 BUG_ON(gh->gh_owner_pid == NULL);
960 if (test_and_set_bit(HIF_WAIT, &gh->gh_iflags))
961 BUG();
962
963 if (gh->gh_flags & (LM_FLAG_TRY | LM_FLAG_TRY_1CB)) {
964 if (test_bit(GLF_LOCK, &gl->gl_flags))
965 try_futile = !may_grant(gl, gh);
966 if (test_bit(GLF_INVALIDATE_IN_PROGRESS, &gl->gl_flags))
967 goto fail;
968 }
969
970 list_for_each_entry(gh2, &gl->gl_holders, gh_list) {
971 if (unlikely(gh2->gh_owner_pid == gh->gh_owner_pid &&
972 (gh->gh_gl->gl_ops->go_type != LM_TYPE_FLOCK)))
973 goto trap_recursive;
974 if (try_futile &&
975 !(gh2->gh_flags & (LM_FLAG_TRY | LM_FLAG_TRY_1CB))) {
976 fail:
977 gh->gh_error = GLR_TRYFAILED;
978 gfs2_holder_wake(gh);
979 return;
980 }
981 if (test_bit(HIF_HOLDER, &gh2->gh_iflags))
982 continue;
983 if (unlikely((gh->gh_flags & LM_FLAG_PRIORITY) && !insert_pt))
984 insert_pt = &gh2->gh_list;
985 }
986 set_bit(GLF_QUEUED, &gl->gl_flags);
987 trace_gfs2_glock_queue(gh, 1);
988 gfs2_glstats_inc(gl, GFS2_LKS_QCOUNT);
989 gfs2_sbstats_inc(gl, GFS2_LKS_QCOUNT);
990 if (likely(insert_pt == NULL)) {
991 list_add_tail(&gh->gh_list, &gl->gl_holders);
992 if (unlikely(gh->gh_flags & LM_FLAG_PRIORITY))
993 goto do_cancel;
994 return;
995 }
996 list_add_tail(&gh->gh_list, insert_pt);
997 do_cancel:
998 gh = list_entry(gl->gl_holders.next, struct gfs2_holder, gh_list);
999 if (!(gh->gh_flags & LM_FLAG_PRIORITY)) {
1000 spin_unlock(&gl->gl_spin);
1001 if (sdp->sd_lockstruct.ls_ops->lm_cancel)
1002 sdp->sd_lockstruct.ls_ops->lm_cancel(gl);
1003 spin_lock(&gl->gl_spin);
1004 }
1005 return;
1006
1007 trap_recursive:
1008 print_symbol(KERN_ERR "original: %s\n", gh2->gh_ip);
1009 printk(KERN_ERR "pid: %d\n", pid_nr(gh2->gh_owner_pid));
1010 printk(KERN_ERR "lock type: %d req lock state : %d\n",
1011 gh2->gh_gl->gl_name.ln_type, gh2->gh_state);
1012 print_symbol(KERN_ERR "new: %s\n", gh->gh_ip);
1013 printk(KERN_ERR "pid: %d\n", pid_nr(gh->gh_owner_pid));
1014 printk(KERN_ERR "lock type: %d req lock state : %d\n",
1015 gh->gh_gl->gl_name.ln_type, gh->gh_state);
1016 __dump_glock(NULL, gl);
1017 BUG();
1018 }
1019
1020 /**
1021 * gfs2_glock_nq - enqueue a struct gfs2_holder onto a glock (acquire a glock)
1022 * @gh: the holder structure
1023 *
1024 * if (gh->gh_flags & GL_ASYNC), this never returns an error
1025 *
1026 * Returns: 0, GLR_TRYFAILED, or errno on failure
1027 */
1028
1029 int gfs2_glock_nq(struct gfs2_holder *gh)
1030 {
1031 struct gfs2_glock *gl = gh->gh_gl;
1032 struct gfs2_sbd *sdp = gl->gl_sbd;
1033 int error = 0;
1034
1035 if (unlikely(test_bit(SDF_SHUTDOWN, &sdp->sd_flags)))
1036 return -EIO;
1037
1038 if (test_bit(GLF_LRU, &gl->gl_flags))
1039 gfs2_glock_remove_from_lru(gl);
1040
1041 spin_lock(&gl->gl_spin);
1042 add_to_queue(gh);
1043 if ((LM_FLAG_NOEXP & gh->gh_flags) &&
1044 test_and_clear_bit(GLF_FROZEN, &gl->gl_flags))
1045 set_bit(GLF_REPLY_PENDING, &gl->gl_flags);
1046 run_queue(gl, 1);
1047 spin_unlock(&gl->gl_spin);
1048
1049 if (!(gh->gh_flags & GL_ASYNC))
1050 error = gfs2_glock_wait(gh);
1051
1052 return error;
1053 }
1054
1055 /**
1056 * gfs2_glock_poll - poll to see if an async request has been completed
1057 * @gh: the holder
1058 *
1059 * Returns: 1 if the request is ready to be gfs2_glock_wait()ed on
1060 */
1061
1062 int gfs2_glock_poll(struct gfs2_holder *gh)
1063 {
1064 return test_bit(HIF_WAIT, &gh->gh_iflags) ? 0 : 1;
1065 }
1066
1067 /**
1068 * gfs2_glock_dq - dequeue a struct gfs2_holder from a glock (release a glock)
1069 * @gh: the glock holder
1070 *
1071 */
1072
1073 void gfs2_glock_dq(struct gfs2_holder *gh)
1074 {
1075 struct gfs2_glock *gl = gh->gh_gl;
1076 const struct gfs2_glock_operations *glops = gl->gl_ops;
1077 unsigned delay = 0;
1078 int fast_path = 0;
1079
1080 spin_lock(&gl->gl_spin);
1081 if (gh->gh_flags & GL_NOCACHE)
1082 handle_callback(gl, LM_ST_UNLOCKED, 0);
1083
1084 list_del_init(&gh->gh_list);
1085 if (find_first_holder(gl) == NULL) {
1086 if (glops->go_unlock) {
1087 GLOCK_BUG_ON(gl, test_and_set_bit(GLF_LOCK, &gl->gl_flags));
1088 spin_unlock(&gl->gl_spin);
1089 glops->go_unlock(gh);
1090 spin_lock(&gl->gl_spin);
1091 clear_bit(GLF_LOCK, &gl->gl_flags);
1092 }
1093 if (list_empty(&gl->gl_holders) &&
1094 !test_bit(GLF_PENDING_DEMOTE, &gl->gl_flags) &&
1095 !test_bit(GLF_DEMOTE, &gl->gl_flags))
1096 fast_path = 1;
1097 }
1098 if (!test_bit(GLF_LFLUSH, &gl->gl_flags) && demote_ok(gl))
1099 gfs2_glock_add_to_lru(gl);
1100
1101 trace_gfs2_glock_queue(gh, 0);
1102 spin_unlock(&gl->gl_spin);
1103 if (likely(fast_path))
1104 return;
1105
1106 gfs2_glock_hold(gl);
1107 if (test_bit(GLF_PENDING_DEMOTE, &gl->gl_flags) &&
1108 !test_bit(GLF_DEMOTE, &gl->gl_flags) &&
1109 gl->gl_name.ln_type == LM_TYPE_INODE)
1110 delay = gl->gl_hold_time;
1111 if (queue_delayed_work(glock_workqueue, &gl->gl_work, delay) == 0)
1112 gfs2_glock_put(gl);
1113 }
1114
1115 void gfs2_glock_dq_wait(struct gfs2_holder *gh)
1116 {
1117 struct gfs2_glock *gl = gh->gh_gl;
1118 gfs2_glock_dq(gh);
1119 might_sleep();
1120 wait_on_bit(&gl->gl_flags, GLF_DEMOTE, gfs2_glock_demote_wait, TASK_UNINTERRUPTIBLE);
1121 }
1122
1123 /**
1124 * gfs2_glock_dq_uninit - dequeue a holder from a glock and initialize it
1125 * @gh: the holder structure
1126 *
1127 */
1128
1129 void gfs2_glock_dq_uninit(struct gfs2_holder *gh)
1130 {
1131 gfs2_glock_dq(gh);
1132 gfs2_holder_uninit(gh);
1133 }
1134
1135 /**
1136 * gfs2_glock_nq_num - acquire a glock based on lock number
1137 * @sdp: the filesystem
1138 * @number: the lock number
1139 * @glops: the glock operations for the type of glock
1140 * @state: the state to acquire the glock in
1141 * @flags: modifier flags for the acquisition
1142 * @gh: the struct gfs2_holder
1143 *
1144 * Returns: errno
1145 */
1146
1147 int gfs2_glock_nq_num(struct gfs2_sbd *sdp, u64 number,
1148 const struct gfs2_glock_operations *glops,
1149 unsigned int state, int flags, struct gfs2_holder *gh)
1150 {
1151 struct gfs2_glock *gl;
1152 int error;
1153
1154 error = gfs2_glock_get(sdp, number, glops, CREATE, &gl);
1155 if (!error) {
1156 error = gfs2_glock_nq_init(gl, state, flags, gh);
1157 gfs2_glock_put(gl);
1158 }
1159
1160 return error;
1161 }
1162
1163 /**
1164 * glock_compare - Compare two struct gfs2_glock structures for sorting
1165 * @arg_a: the first structure
1166 * @arg_b: the second structure
1167 *
1168 */
1169
1170 static int glock_compare(const void *arg_a, const void *arg_b)
1171 {
1172 const struct gfs2_holder *gh_a = *(const struct gfs2_holder **)arg_a;
1173 const struct gfs2_holder *gh_b = *(const struct gfs2_holder **)arg_b;
1174 const struct lm_lockname *a = &gh_a->gh_gl->gl_name;
1175 const struct lm_lockname *b = &gh_b->gh_gl->gl_name;
1176
1177 if (a->ln_number > b->ln_number)
1178 return 1;
1179 if (a->ln_number < b->ln_number)
1180 return -1;
1181 BUG_ON(gh_a->gh_gl->gl_ops->go_type == gh_b->gh_gl->gl_ops->go_type);
1182 return 0;
1183 }
1184
1185 /**
1186 * nq_m_sync - synchonously acquire more than one glock in deadlock free order
1187 * @num_gh: the number of structures
1188 * @ghs: an array of struct gfs2_holder structures
1189 *
1190 * Returns: 0 on success (all glocks acquired),
1191 * errno on failure (no glocks acquired)
1192 */
1193
1194 static int nq_m_sync(unsigned int num_gh, struct gfs2_holder *ghs,
1195 struct gfs2_holder **p)
1196 {
1197 unsigned int x;
1198 int error = 0;
1199
1200 for (x = 0; x < num_gh; x++)
1201 p[x] = &ghs[x];
1202
1203 sort(p, num_gh, sizeof(struct gfs2_holder *), glock_compare, NULL);
1204
1205 for (x = 0; x < num_gh; x++) {
1206 p[x]->gh_flags &= ~(LM_FLAG_TRY | GL_ASYNC);
1207
1208 error = gfs2_glock_nq(p[x]);
1209 if (error) {
1210 while (x--)
1211 gfs2_glock_dq(p[x]);
1212 break;
1213 }
1214 }
1215
1216 return error;
1217 }
1218
1219 /**
1220 * gfs2_glock_nq_m - acquire multiple glocks
1221 * @num_gh: the number of structures
1222 * @ghs: an array of struct gfs2_holder structures
1223 *
1224 *
1225 * Returns: 0 on success (all glocks acquired),
1226 * errno on failure (no glocks acquired)
1227 */
1228
1229 int gfs2_glock_nq_m(unsigned int num_gh, struct gfs2_holder *ghs)
1230 {
1231 struct gfs2_holder *tmp[4];
1232 struct gfs2_holder **pph = tmp;
1233 int error = 0;
1234
1235 switch(num_gh) {
1236 case 0:
1237 return 0;
1238 case 1:
1239 ghs->gh_flags &= ~(LM_FLAG_TRY | GL_ASYNC);
1240 return gfs2_glock_nq(ghs);
1241 default:
1242 if (num_gh <= 4)
1243 break;
1244 pph = kmalloc(num_gh * sizeof(struct gfs2_holder *), GFP_NOFS);
1245 if (!pph)
1246 return -ENOMEM;
1247 }
1248
1249 error = nq_m_sync(num_gh, ghs, pph);
1250
1251 if (pph != tmp)
1252 kfree(pph);
1253
1254 return error;
1255 }
1256
1257 /**
1258 * gfs2_glock_dq_m - release multiple glocks
1259 * @num_gh: the number of structures
1260 * @ghs: an array of struct gfs2_holder structures
1261 *
1262 */
1263
1264 void gfs2_glock_dq_m(unsigned int num_gh, struct gfs2_holder *ghs)
1265 {
1266 while (num_gh--)
1267 gfs2_glock_dq(&ghs[num_gh]);
1268 }
1269
1270 /**
1271 * gfs2_glock_dq_uninit_m - release multiple glocks
1272 * @num_gh: the number of structures
1273 * @ghs: an array of struct gfs2_holder structures
1274 *
1275 */
1276
1277 void gfs2_glock_dq_uninit_m(unsigned int num_gh, struct gfs2_holder *ghs)
1278 {
1279 while (num_gh--)
1280 gfs2_glock_dq_uninit(&ghs[num_gh]);
1281 }
1282
1283 void gfs2_glock_cb(struct gfs2_glock *gl, unsigned int state)
1284 {
1285 unsigned long delay = 0;
1286 unsigned long holdtime;
1287 unsigned long now = jiffies;
1288
1289 gfs2_glock_hold(gl);
1290 holdtime = gl->gl_tchange + gl->gl_hold_time;
1291 if (test_bit(GLF_QUEUED, &gl->gl_flags) &&
1292 gl->gl_name.ln_type == LM_TYPE_INODE) {
1293 if (time_before(now, holdtime))
1294 delay = holdtime - now;
1295 if (test_bit(GLF_REPLY_PENDING, &gl->gl_flags))
1296 delay = gl->gl_hold_time;
1297 }
1298
1299 spin_lock(&gl->gl_spin);
1300 handle_callback(gl, state, delay);
1301 spin_unlock(&gl->gl_spin);
1302 if (queue_delayed_work(glock_workqueue, &gl->gl_work, delay) == 0)
1303 gfs2_glock_put(gl);
1304 }
1305
1306 /**
1307 * gfs2_should_freeze - Figure out if glock should be frozen
1308 * @gl: The glock in question
1309 *
1310 * Glocks are not frozen if (a) the result of the dlm operation is
1311 * an error, (b) the locking operation was an unlock operation or
1312 * (c) if there is a "noexp" flagged request anywhere in the queue
1313 *
1314 * Returns: 1 if freezing should occur, 0 otherwise
1315 */
1316
1317 static int gfs2_should_freeze(const struct gfs2_glock *gl)
1318 {
1319 const struct gfs2_holder *gh;
1320
1321 if (gl->gl_reply & ~LM_OUT_ST_MASK)
1322 return 0;
1323 if (gl->gl_target == LM_ST_UNLOCKED)
1324 return 0;
1325
1326 list_for_each_entry(gh, &gl->gl_holders, gh_list) {
1327 if (test_bit(HIF_HOLDER, &gh->gh_iflags))
1328 continue;
1329 if (LM_FLAG_NOEXP & gh->gh_flags)
1330 return 0;
1331 }
1332
1333 return 1;
1334 }
1335
1336 /**
1337 * gfs2_glock_complete - Callback used by locking
1338 * @gl: Pointer to the glock
1339 * @ret: The return value from the dlm
1340 *
1341 * The gl_reply field is under the gl_spin lock so that it is ok
1342 * to use a bitfield shared with other glock state fields.
1343 */
1344
1345 void gfs2_glock_complete(struct gfs2_glock *gl, int ret)
1346 {
1347 struct lm_lockstruct *ls = &gl->gl_sbd->sd_lockstruct;
1348
1349 spin_lock(&gl->gl_spin);
1350 gl->gl_reply = ret;
1351
1352 if (unlikely(test_bit(DFL_BLOCK_LOCKS, &ls->ls_recover_flags))) {
1353 if (gfs2_should_freeze(gl)) {
1354 set_bit(GLF_FROZEN, &gl->gl_flags);
1355 spin_unlock(&gl->gl_spin);
1356 return;
1357 }
1358 }
1359
1360 spin_unlock(&gl->gl_spin);
1361 set_bit(GLF_REPLY_PENDING, &gl->gl_flags);
1362 smp_wmb();
1363 gfs2_glock_hold(gl);
1364 if (queue_delayed_work(glock_workqueue, &gl->gl_work, 0) == 0)
1365 gfs2_glock_put(gl);
1366 }
1367
1368
1369 static int gfs2_shrink_glock_memory(struct shrinker *shrink,
1370 struct shrink_control *sc)
1371 {
1372 struct gfs2_glock *gl;
1373 int may_demote;
1374 int nr_skipped = 0;
1375 int nr = sc->nr_to_scan;
1376 gfp_t gfp_mask = sc->gfp_mask;
1377 LIST_HEAD(skipped);
1378
1379 if (nr == 0)
1380 goto out;
1381
1382 if (!(gfp_mask & __GFP_FS))
1383 return -1;
1384
1385 spin_lock(&lru_lock);
1386 while(nr && !list_empty(&lru_list)) {
1387 gl = list_entry(lru_list.next, struct gfs2_glock, gl_lru);
1388 list_del_init(&gl->gl_lru);
1389 clear_bit(GLF_LRU, &gl->gl_flags);
1390 atomic_dec(&lru_count);
1391
1392 /* Test for being demotable */
1393 if (!test_and_set_bit(GLF_LOCK, &gl->gl_flags)) {
1394 gfs2_glock_hold(gl);
1395 spin_unlock(&lru_lock);
1396 spin_lock(&gl->gl_spin);
1397 may_demote = demote_ok(gl);
1398 if (may_demote) {
1399 handle_callback(gl, LM_ST_UNLOCKED, 0);
1400 nr--;
1401 }
1402 clear_bit(GLF_LOCK, &gl->gl_flags);
1403 smp_mb__after_clear_bit();
1404 if (queue_delayed_work(glock_workqueue, &gl->gl_work, 0) == 0)
1405 gfs2_glock_put_nolock(gl);
1406 spin_unlock(&gl->gl_spin);
1407 spin_lock(&lru_lock);
1408 continue;
1409 }
1410 nr_skipped++;
1411 list_add(&gl->gl_lru, &skipped);
1412 set_bit(GLF_LRU, &gl->gl_flags);
1413 }
1414 list_splice(&skipped, &lru_list);
1415 atomic_add(nr_skipped, &lru_count);
1416 spin_unlock(&lru_lock);
1417 out:
1418 return (atomic_read(&lru_count) / 100) * sysctl_vfs_cache_pressure;
1419 }
1420
1421 static struct shrinker glock_shrinker = {
1422 .shrink = gfs2_shrink_glock_memory,
1423 .seeks = DEFAULT_SEEKS,
1424 };
1425
1426 /**
1427 * examine_bucket - Call a function for glock in a hash bucket
1428 * @examiner: the function
1429 * @sdp: the filesystem
1430 * @bucket: the bucket
1431 *
1432 */
1433
1434 static void examine_bucket(glock_examiner examiner, const struct gfs2_sbd *sdp,
1435 unsigned int hash)
1436 {
1437 struct gfs2_glock *gl;
1438 struct hlist_bl_head *head = &gl_hash_table[hash];
1439 struct hlist_bl_node *pos;
1440
1441 rcu_read_lock();
1442 hlist_bl_for_each_entry_rcu(gl, pos, head, gl_list) {
1443 if ((gl->gl_sbd == sdp) && atomic_read(&gl->gl_ref))
1444 examiner(gl);
1445 }
1446 rcu_read_unlock();
1447 cond_resched();
1448 }
1449
1450 static void glock_hash_walk(glock_examiner examiner, const struct gfs2_sbd *sdp)
1451 {
1452 unsigned x;
1453
1454 for (x = 0; x < GFS2_GL_HASH_SIZE; x++)
1455 examine_bucket(examiner, sdp, x);
1456 }
1457
1458
1459 /**
1460 * thaw_glock - thaw out a glock which has an unprocessed reply waiting
1461 * @gl: The glock to thaw
1462 *
1463 * N.B. When we freeze a glock, we leave a ref to the glock outstanding,
1464 * so this has to result in the ref count being dropped by one.
1465 */
1466
1467 static void thaw_glock(struct gfs2_glock *gl)
1468 {
1469 if (!test_and_clear_bit(GLF_FROZEN, &gl->gl_flags))
1470 return;
1471 set_bit(GLF_REPLY_PENDING, &gl->gl_flags);
1472 gfs2_glock_hold(gl);
1473 if (queue_delayed_work(glock_workqueue, &gl->gl_work, 0) == 0)
1474 gfs2_glock_put(gl);
1475 }
1476
1477 /**
1478 * clear_glock - look at a glock and see if we can free it from glock cache
1479 * @gl: the glock to look at
1480 *
1481 */
1482
1483 static void clear_glock(struct gfs2_glock *gl)
1484 {
1485 gfs2_glock_remove_from_lru(gl);
1486
1487 spin_lock(&gl->gl_spin);
1488 if (gl->gl_state != LM_ST_UNLOCKED)
1489 handle_callback(gl, LM_ST_UNLOCKED, 0);
1490 spin_unlock(&gl->gl_spin);
1491 gfs2_glock_hold(gl);
1492 if (queue_delayed_work(glock_workqueue, &gl->gl_work, 0) == 0)
1493 gfs2_glock_put(gl);
1494 }
1495
1496 /**
1497 * gfs2_glock_thaw - Thaw any frozen glocks
1498 * @sdp: The super block
1499 *
1500 */
1501
1502 void gfs2_glock_thaw(struct gfs2_sbd *sdp)
1503 {
1504 glock_hash_walk(thaw_glock, sdp);
1505 }
1506
1507 static int dump_glock(struct seq_file *seq, struct gfs2_glock *gl)
1508 {
1509 int ret;
1510 spin_lock(&gl->gl_spin);
1511 ret = __dump_glock(seq, gl);
1512 spin_unlock(&gl->gl_spin);
1513 return ret;
1514 }
1515
1516 static void dump_glock_func(struct gfs2_glock *gl)
1517 {
1518 dump_glock(NULL, gl);
1519 }
1520
1521 /**
1522 * gfs2_gl_hash_clear - Empty out the glock hash table
1523 * @sdp: the filesystem
1524 * @wait: wait until it's all gone
1525 *
1526 * Called when unmounting the filesystem.
1527 */
1528
1529 void gfs2_gl_hash_clear(struct gfs2_sbd *sdp)
1530 {
1531 glock_hash_walk(clear_glock, sdp);
1532 flush_workqueue(glock_workqueue);
1533 wait_event(sdp->sd_glock_wait, atomic_read(&sdp->sd_glock_disposal) == 0);
1534 glock_hash_walk(dump_glock_func, sdp);
1535 }
1536
1537 void gfs2_glock_finish_truncate(struct gfs2_inode *ip)
1538 {
1539 struct gfs2_glock *gl = ip->i_gl;
1540 int ret;
1541
1542 ret = gfs2_truncatei_resume(ip);
1543 gfs2_assert_withdraw(gl->gl_sbd, ret == 0);
1544
1545 spin_lock(&gl->gl_spin);
1546 clear_bit(GLF_LOCK, &gl->gl_flags);
1547 run_queue(gl, 1);
1548 spin_unlock(&gl->gl_spin);
1549 }
1550
1551 static const char *state2str(unsigned state)
1552 {
1553 switch(state) {
1554 case LM_ST_UNLOCKED:
1555 return "UN";
1556 case LM_ST_SHARED:
1557 return "SH";
1558 case LM_ST_DEFERRED:
1559 return "DF";
1560 case LM_ST_EXCLUSIVE:
1561 return "EX";
1562 }
1563 return "??";
1564 }
1565
1566 static const char *hflags2str(char *buf, unsigned flags, unsigned long iflags)
1567 {
1568 char *p = buf;
1569 if (flags & LM_FLAG_TRY)
1570 *p++ = 't';
1571 if (flags & LM_FLAG_TRY_1CB)
1572 *p++ = 'T';
1573 if (flags & LM_FLAG_NOEXP)
1574 *p++ = 'e';
1575 if (flags & LM_FLAG_ANY)
1576 *p++ = 'A';
1577 if (flags & LM_FLAG_PRIORITY)
1578 *p++ = 'p';
1579 if (flags & GL_ASYNC)
1580 *p++ = 'a';
1581 if (flags & GL_EXACT)
1582 *p++ = 'E';
1583 if (flags & GL_NOCACHE)
1584 *p++ = 'c';
1585 if (test_bit(HIF_HOLDER, &iflags))
1586 *p++ = 'H';
1587 if (test_bit(HIF_WAIT, &iflags))
1588 *p++ = 'W';
1589 if (test_bit(HIF_FIRST, &iflags))
1590 *p++ = 'F';
1591 *p = 0;
1592 return buf;
1593 }
1594
1595 /**
1596 * dump_holder - print information about a glock holder
1597 * @seq: the seq_file struct
1598 * @gh: the glock holder
1599 *
1600 * Returns: 0 on success, -ENOBUFS when we run out of space
1601 */
1602
1603 static int dump_holder(struct seq_file *seq, const struct gfs2_holder *gh)
1604 {
1605 struct task_struct *gh_owner = NULL;
1606 char flags_buf[32];
1607
1608 if (gh->gh_owner_pid)
1609 gh_owner = pid_task(gh->gh_owner_pid, PIDTYPE_PID);
1610 gfs2_print_dbg(seq, " H: s:%s f:%s e:%d p:%ld [%s] %pS\n",
1611 state2str(gh->gh_state),
1612 hflags2str(flags_buf, gh->gh_flags, gh->gh_iflags),
1613 gh->gh_error,
1614 gh->gh_owner_pid ? (long)pid_nr(gh->gh_owner_pid) : -1,
1615 gh_owner ? gh_owner->comm : "(ended)",
1616 (void *)gh->gh_ip);
1617 return 0;
1618 }
1619
1620 static const char *gflags2str(char *buf, const struct gfs2_glock *gl)
1621 {
1622 const unsigned long *gflags = &gl->gl_flags;
1623 char *p = buf;
1624
1625 if (test_bit(GLF_LOCK, gflags))
1626 *p++ = 'l';
1627 if (test_bit(GLF_DEMOTE, gflags))
1628 *p++ = 'D';
1629 if (test_bit(GLF_PENDING_DEMOTE, gflags))
1630 *p++ = 'd';
1631 if (test_bit(GLF_DEMOTE_IN_PROGRESS, gflags))
1632 *p++ = 'p';
1633 if (test_bit(GLF_DIRTY, gflags))
1634 *p++ = 'y';
1635 if (test_bit(GLF_LFLUSH, gflags))
1636 *p++ = 'f';
1637 if (test_bit(GLF_INVALIDATE_IN_PROGRESS, gflags))
1638 *p++ = 'i';
1639 if (test_bit(GLF_REPLY_PENDING, gflags))
1640 *p++ = 'r';
1641 if (test_bit(GLF_INITIAL, gflags))
1642 *p++ = 'I';
1643 if (test_bit(GLF_FROZEN, gflags))
1644 *p++ = 'F';
1645 if (test_bit(GLF_QUEUED, gflags))
1646 *p++ = 'q';
1647 if (test_bit(GLF_LRU, gflags))
1648 *p++ = 'L';
1649 if (gl->gl_object)
1650 *p++ = 'o';
1651 if (test_bit(GLF_BLOCKING, gflags))
1652 *p++ = 'b';
1653 *p = 0;
1654 return buf;
1655 }
1656
1657 /**
1658 * __dump_glock - print information about a glock
1659 * @seq: The seq_file struct
1660 * @gl: the glock
1661 *
1662 * The file format is as follows:
1663 * One line per object, capital letters are used to indicate objects
1664 * G = glock, I = Inode, R = rgrp, H = holder. Glocks are not indented,
1665 * other objects are indented by a single space and follow the glock to
1666 * which they are related. Fields are indicated by lower case letters
1667 * followed by a colon and the field value, except for strings which are in
1668 * [] so that its possible to see if they are composed of spaces for
1669 * example. The field's are n = number (id of the object), f = flags,
1670 * t = type, s = state, r = refcount, e = error, p = pid.
1671 *
1672 * Returns: 0 on success, -ENOBUFS when we run out of space
1673 */
1674
1675 static int __dump_glock(struct seq_file *seq, const struct gfs2_glock *gl)
1676 {
1677 const struct gfs2_glock_operations *glops = gl->gl_ops;
1678 unsigned long long dtime;
1679 const struct gfs2_holder *gh;
1680 char gflags_buf[32];
1681 int error = 0;
1682
1683 dtime = jiffies - gl->gl_demote_time;
1684 dtime *= 1000000/HZ; /* demote time in uSec */
1685 if (!test_bit(GLF_DEMOTE, &gl->gl_flags))
1686 dtime = 0;
1687 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",
1688 state2str(gl->gl_state),
1689 gl->gl_name.ln_type,
1690 (unsigned long long)gl->gl_name.ln_number,
1691 gflags2str(gflags_buf, gl),
1692 state2str(gl->gl_target),
1693 state2str(gl->gl_demote_state), dtime,
1694 atomic_read(&gl->gl_ail_count),
1695 atomic_read(&gl->gl_revokes),
1696 atomic_read(&gl->gl_ref), gl->gl_hold_time);
1697
1698 list_for_each_entry(gh, &gl->gl_holders, gh_list) {
1699 error = dump_holder(seq, gh);
1700 if (error)
1701 goto out;
1702 }
1703 if (gl->gl_state != LM_ST_UNLOCKED && glops->go_dump)
1704 error = glops->go_dump(seq, gl);
1705 out:
1706 return error;
1707 }
1708
1709 static int gfs2_glstats_seq_show(struct seq_file *seq, void *iter_ptr)
1710 {
1711 struct gfs2_glock *gl = iter_ptr;
1712
1713 seq_printf(seq, "G: n:%u/%llx rtt:%lld/%lld rttb:%lld/%lld irt:%lld/%lld dcnt: %lld qcnt: %lld\n",
1714 gl->gl_name.ln_type,
1715 (unsigned long long)gl->gl_name.ln_number,
1716 (long long)gl->gl_stats.stats[GFS2_LKS_SRTT],
1717 (long long)gl->gl_stats.stats[GFS2_LKS_SRTTVAR],
1718 (long long)gl->gl_stats.stats[GFS2_LKS_SRTTB],
1719 (long long)gl->gl_stats.stats[GFS2_LKS_SRTTVARB],
1720 (long long)gl->gl_stats.stats[GFS2_LKS_SIRT],
1721 (long long)gl->gl_stats.stats[GFS2_LKS_SIRTVAR],
1722 (long long)gl->gl_stats.stats[GFS2_LKS_DCOUNT],
1723 (long long)gl->gl_stats.stats[GFS2_LKS_QCOUNT]);
1724 return 0;
1725 }
1726
1727 static const char *gfs2_gltype[] = {
1728 "type",
1729 "reserved",
1730 "nondisk",
1731 "inode",
1732 "rgrp",
1733 "meta",
1734 "iopen",
1735 "flock",
1736 "plock",
1737 "quota",
1738 "journal",
1739 };
1740
1741 static const char *gfs2_stype[] = {
1742 [GFS2_LKS_SRTT] = "srtt",
1743 [GFS2_LKS_SRTTVAR] = "srttvar",
1744 [GFS2_LKS_SRTTB] = "srttb",
1745 [GFS2_LKS_SRTTVARB] = "srttvarb",
1746 [GFS2_LKS_SIRT] = "sirt",
1747 [GFS2_LKS_SIRTVAR] = "sirtvar",
1748 [GFS2_LKS_DCOUNT] = "dlm",
1749 [GFS2_LKS_QCOUNT] = "queue",
1750 };
1751
1752 #define GFS2_NR_SBSTATS (ARRAY_SIZE(gfs2_gltype) * ARRAY_SIZE(gfs2_stype))
1753
1754 static int gfs2_sbstats_seq_show(struct seq_file *seq, void *iter_ptr)
1755 {
1756 struct gfs2_glock_iter *gi = seq->private;
1757 struct gfs2_sbd *sdp = gi->sdp;
1758 unsigned index = gi->hash >> 3;
1759 unsigned subindex = gi->hash & 0x07;
1760 s64 value;
1761 int i;
1762
1763 if (index == 0 && subindex != 0)
1764 return 0;
1765
1766 seq_printf(seq, "%-10s %8s:", gfs2_gltype[index],
1767 (index == 0) ? "cpu": gfs2_stype[subindex]);
1768
1769 for_each_possible_cpu(i) {
1770 const struct gfs2_pcpu_lkstats *lkstats = per_cpu_ptr(sdp->sd_lkstats, i);
1771 if (index == 0) {
1772 value = i;
1773 } else {
1774 value = lkstats->lkstats[index - 1].stats[subindex];
1775 }
1776 seq_printf(seq, " %15lld", (long long)value);
1777 }
1778 seq_putc(seq, '\n');
1779 return 0;
1780 }
1781
1782 int __init gfs2_glock_init(void)
1783 {
1784 unsigned i;
1785 for(i = 0; i < GFS2_GL_HASH_SIZE; i++) {
1786 INIT_HLIST_BL_HEAD(&gl_hash_table[i]);
1787 }
1788
1789 glock_workqueue = alloc_workqueue("glock_workqueue", WQ_MEM_RECLAIM |
1790 WQ_HIGHPRI | WQ_FREEZABLE, 0);
1791 if (IS_ERR(glock_workqueue))
1792 return PTR_ERR(glock_workqueue);
1793 gfs2_delete_workqueue = alloc_workqueue("delete_workqueue",
1794 WQ_MEM_RECLAIM | WQ_FREEZABLE,
1795 0);
1796 if (IS_ERR(gfs2_delete_workqueue)) {
1797 destroy_workqueue(glock_workqueue);
1798 return PTR_ERR(gfs2_delete_workqueue);
1799 }
1800
1801 register_shrinker(&glock_shrinker);
1802
1803 return 0;
1804 }
1805
1806 void gfs2_glock_exit(void)
1807 {
1808 unregister_shrinker(&glock_shrinker);
1809 destroy_workqueue(glock_workqueue);
1810 destroy_workqueue(gfs2_delete_workqueue);
1811 }
1812
1813 static inline struct gfs2_glock *glock_hash_chain(unsigned hash)
1814 {
1815 return hlist_bl_entry(hlist_bl_first_rcu(&gl_hash_table[hash]),
1816 struct gfs2_glock, gl_list);
1817 }
1818
1819 static inline struct gfs2_glock *glock_hash_next(struct gfs2_glock *gl)
1820 {
1821 return hlist_bl_entry(rcu_dereference(gl->gl_list.next),
1822 struct gfs2_glock, gl_list);
1823 }
1824
1825 static int gfs2_glock_iter_next(struct gfs2_glock_iter *gi)
1826 {
1827 struct gfs2_glock *gl;
1828
1829 do {
1830 gl = gi->gl;
1831 if (gl) {
1832 gi->gl = glock_hash_next(gl);
1833 gi->nhash++;
1834 } else {
1835 if (gi->hash >= GFS2_GL_HASH_SIZE) {
1836 rcu_read_unlock();
1837 return 1;
1838 }
1839 gi->gl = glock_hash_chain(gi->hash);
1840 gi->nhash = 0;
1841 }
1842 while (gi->gl == NULL) {
1843 gi->hash++;
1844 if (gi->hash >= GFS2_GL_HASH_SIZE) {
1845 rcu_read_unlock();
1846 return 1;
1847 }
1848 gi->gl = glock_hash_chain(gi->hash);
1849 gi->nhash = 0;
1850 }
1851 /* Skip entries for other sb and dead entries */
1852 } while (gi->sdp != gi->gl->gl_sbd || atomic_read(&gi->gl->gl_ref) == 0);
1853
1854 return 0;
1855 }
1856
1857 static void *gfs2_glock_seq_start(struct seq_file *seq, loff_t *pos)
1858 {
1859 struct gfs2_glock_iter *gi = seq->private;
1860 loff_t n = *pos;
1861
1862 if (gi->last_pos <= *pos)
1863 n = gi->nhash + (*pos - gi->last_pos);
1864 else
1865 gi->hash = 0;
1866
1867 gi->nhash = 0;
1868 rcu_read_lock();
1869
1870 do {
1871 if (gfs2_glock_iter_next(gi))
1872 return NULL;
1873 } while (n--);
1874
1875 gi->last_pos = *pos;
1876 return gi->gl;
1877 }
1878
1879 static void *gfs2_glock_seq_next(struct seq_file *seq, void *iter_ptr,
1880 loff_t *pos)
1881 {
1882 struct gfs2_glock_iter *gi = seq->private;
1883
1884 (*pos)++;
1885 gi->last_pos = *pos;
1886 if (gfs2_glock_iter_next(gi))
1887 return NULL;
1888
1889 return gi->gl;
1890 }
1891
1892 static void gfs2_glock_seq_stop(struct seq_file *seq, void *iter_ptr)
1893 {
1894 struct gfs2_glock_iter *gi = seq->private;
1895
1896 if (gi->gl)
1897 rcu_read_unlock();
1898 gi->gl = NULL;
1899 }
1900
1901 static int gfs2_glock_seq_show(struct seq_file *seq, void *iter_ptr)
1902 {
1903 return dump_glock(seq, iter_ptr);
1904 }
1905
1906 static void *gfs2_sbstats_seq_start(struct seq_file *seq, loff_t *pos)
1907 {
1908 struct gfs2_glock_iter *gi = seq->private;
1909
1910 gi->hash = *pos;
1911 if (*pos >= GFS2_NR_SBSTATS)
1912 return NULL;
1913 preempt_disable();
1914 return SEQ_START_TOKEN;
1915 }
1916
1917 static void *gfs2_sbstats_seq_next(struct seq_file *seq, void *iter_ptr,
1918 loff_t *pos)
1919 {
1920 struct gfs2_glock_iter *gi = seq->private;
1921 (*pos)++;
1922 gi->hash++;
1923 if (gi->hash >= GFS2_NR_SBSTATS) {
1924 preempt_enable();
1925 return NULL;
1926 }
1927 return SEQ_START_TOKEN;
1928 }
1929
1930 static void gfs2_sbstats_seq_stop(struct seq_file *seq, void *iter_ptr)
1931 {
1932 preempt_enable();
1933 }
1934
1935 static const struct seq_operations gfs2_glock_seq_ops = {
1936 .start = gfs2_glock_seq_start,
1937 .next = gfs2_glock_seq_next,
1938 .stop = gfs2_glock_seq_stop,
1939 .show = gfs2_glock_seq_show,
1940 };
1941
1942 static const struct seq_operations gfs2_glstats_seq_ops = {
1943 .start = gfs2_glock_seq_start,
1944 .next = gfs2_glock_seq_next,
1945 .stop = gfs2_glock_seq_stop,
1946 .show = gfs2_glstats_seq_show,
1947 };
1948
1949 static const struct seq_operations gfs2_sbstats_seq_ops = {
1950 .start = gfs2_sbstats_seq_start,
1951 .next = gfs2_sbstats_seq_next,
1952 .stop = gfs2_sbstats_seq_stop,
1953 .show = gfs2_sbstats_seq_show,
1954 };
1955
1956 #define GFS2_SEQ_GOODSIZE min(PAGE_SIZE << PAGE_ALLOC_COSTLY_ORDER, 65536UL)
1957
1958 static int gfs2_glocks_open(struct inode *inode, struct file *file)
1959 {
1960 int ret = seq_open_private(file, &gfs2_glock_seq_ops,
1961 sizeof(struct gfs2_glock_iter));
1962 if (ret == 0) {
1963 struct seq_file *seq = file->private_data;
1964 struct gfs2_glock_iter *gi = seq->private;
1965 gi->sdp = inode->i_private;
1966 seq->buf = kmalloc(GFS2_SEQ_GOODSIZE, GFP_KERNEL | __GFP_NOWARN);
1967 if (seq->buf)
1968 seq->size = GFS2_SEQ_GOODSIZE;
1969 }
1970 return ret;
1971 }
1972
1973 static int gfs2_glstats_open(struct inode *inode, struct file *file)
1974 {
1975 int ret = seq_open_private(file, &gfs2_glstats_seq_ops,
1976 sizeof(struct gfs2_glock_iter));
1977 if (ret == 0) {
1978 struct seq_file *seq = file->private_data;
1979 struct gfs2_glock_iter *gi = seq->private;
1980 gi->sdp = inode->i_private;
1981 seq->buf = kmalloc(GFS2_SEQ_GOODSIZE, GFP_KERNEL | __GFP_NOWARN);
1982 if (seq->buf)
1983 seq->size = GFS2_SEQ_GOODSIZE;
1984 }
1985 return ret;
1986 }
1987
1988 static int gfs2_sbstats_open(struct inode *inode, struct file *file)
1989 {
1990 int ret = seq_open_private(file, &gfs2_sbstats_seq_ops,
1991 sizeof(struct gfs2_glock_iter));
1992 if (ret == 0) {
1993 struct seq_file *seq = file->private_data;
1994 struct gfs2_glock_iter *gi = seq->private;
1995 gi->sdp = inode->i_private;
1996 }
1997 return ret;
1998 }
1999
2000 static const struct file_operations gfs2_glocks_fops = {
2001 .owner = THIS_MODULE,
2002 .open = gfs2_glocks_open,
2003 .read = seq_read,
2004 .llseek = seq_lseek,
2005 .release = seq_release_private,
2006 };
2007
2008 static const struct file_operations gfs2_glstats_fops = {
2009 .owner = THIS_MODULE,
2010 .open = gfs2_glstats_open,
2011 .read = seq_read,
2012 .llseek = seq_lseek,
2013 .release = seq_release_private,
2014 };
2015
2016 static const struct file_operations gfs2_sbstats_fops = {
2017 .owner = THIS_MODULE,
2018 .open = gfs2_sbstats_open,
2019 .read = seq_read,
2020 .llseek = seq_lseek,
2021 .release = seq_release_private,
2022 };
2023
2024 int gfs2_create_debugfs_file(struct gfs2_sbd *sdp)
2025 {
2026 sdp->debugfs_dir = debugfs_create_dir(sdp->sd_table_name, gfs2_root);
2027 if (!sdp->debugfs_dir)
2028 return -ENOMEM;
2029 sdp->debugfs_dentry_glocks = debugfs_create_file("glocks",
2030 S_IFREG | S_IRUGO,
2031 sdp->debugfs_dir, sdp,
2032 &gfs2_glocks_fops);
2033 if (!sdp->debugfs_dentry_glocks)
2034 goto fail;
2035
2036 sdp->debugfs_dentry_glstats = debugfs_create_file("glstats",
2037 S_IFREG | S_IRUGO,
2038 sdp->debugfs_dir, sdp,
2039 &gfs2_glstats_fops);
2040 if (!sdp->debugfs_dentry_glstats)
2041 goto fail;
2042
2043 sdp->debugfs_dentry_sbstats = debugfs_create_file("sbstats",
2044 S_IFREG | S_IRUGO,
2045 sdp->debugfs_dir, sdp,
2046 &gfs2_sbstats_fops);
2047 if (!sdp->debugfs_dentry_sbstats)
2048 goto fail;
2049
2050 return 0;
2051 fail:
2052 gfs2_delete_debugfs_file(sdp);
2053 return -ENOMEM;
2054 }
2055
2056 void gfs2_delete_debugfs_file(struct gfs2_sbd *sdp)
2057 {
2058 if (sdp->debugfs_dir) {
2059 if (sdp->debugfs_dentry_glocks) {
2060 debugfs_remove(sdp->debugfs_dentry_glocks);
2061 sdp->debugfs_dentry_glocks = NULL;
2062 }
2063 if (sdp->debugfs_dentry_glstats) {
2064 debugfs_remove(sdp->debugfs_dentry_glstats);
2065 sdp->debugfs_dentry_glstats = NULL;
2066 }
2067 if (sdp->debugfs_dentry_sbstats) {
2068 debugfs_remove(sdp->debugfs_dentry_sbstats);
2069 sdp->debugfs_dentry_sbstats = NULL;
2070 }
2071 debugfs_remove(sdp->debugfs_dir);
2072 sdp->debugfs_dir = NULL;
2073 }
2074 }
2075
2076 int gfs2_register_debugfs(void)
2077 {
2078 gfs2_root = debugfs_create_dir("gfs2", NULL);
2079 return gfs2_root ? 0 : -ENOMEM;
2080 }
2081
2082 void gfs2_unregister_debugfs(void)
2083 {
2084 debugfs_remove(gfs2_root);
2085 gfs2_root = NULL;
2086 }
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