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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
33#include "gfs2.h"
34#include "incore.h"
35#include "glock.h"
36#include "glops.h"
37#include "inode.h"
38#include "lops.h"
39#include "meta_io.h"
40#include "quota.h"
41#include "super.h"
42#include "util.h"
43#include "bmap.h"
44#define CREATE_TRACE_POINTS
45#include "trace_gfs2.h"
46
47struct gfs2_glock_iter {
48 int hash; /* hash bucket index */
49 struct gfs2_sbd *sdp; /* incore superblock */
50 struct gfs2_glock *gl; /* current glock struct */
51 char string[512]; /* scratch space */
52};
53
54typedef void (*glock_examiner) (struct gfs2_glock * gl);
55
56static int __dump_glock(struct seq_file *seq, const struct gfs2_glock *gl);
57#define GLOCK_BUG_ON(gl,x) do { if (unlikely(x)) { __dump_glock(NULL, gl); BUG(); } } while(0)
58static void do_xmote(struct gfs2_glock *gl, struct gfs2_holder *gh, unsigned int target);
59
60static struct dentry *gfs2_root;
61static struct workqueue_struct *glock_workqueue;
62struct workqueue_struct *gfs2_delete_workqueue;
63static LIST_HEAD(lru_list);
64static atomic_t lru_count = ATOMIC_INIT(0);
65static DEFINE_SPINLOCK(lru_lock);
66
67#define GFS2_GL_HASH_SHIFT 15
68#define GFS2_GL_HASH_SIZE (1 << GFS2_GL_HASH_SHIFT)
69#define GFS2_GL_HASH_MASK (GFS2_GL_HASH_SIZE - 1)
70
71static struct hlist_bl_head gl_hash_table[GFS2_GL_HASH_SIZE];
72static struct dentry *gfs2_root;
73
74/**
75 * gl_hash() - Turn glock number into hash bucket number
76 * @lock: The glock number
77 *
78 * Returns: The number of the corresponding hash bucket
79 */
80
81static unsigned int gl_hash(const struct gfs2_sbd *sdp,
82 const struct lm_lockname *name)
83{
84 unsigned int h;
85
86 h = jhash(&name->ln_number, sizeof(u64), 0);
87 h = jhash(&name->ln_type, sizeof(unsigned int), h);
88 h = jhash(&sdp, sizeof(struct gfs2_sbd *), h);
89 h &= GFS2_GL_HASH_MASK;
90
91 return h;
92}
93
94static inline void spin_lock_bucket(unsigned int hash)
95{
96 hlist_bl_lock(&gl_hash_table[hash]);
97}
98
99static inline void spin_unlock_bucket(unsigned int hash)
100{
101 hlist_bl_unlock(&gl_hash_table[hash]);
102}
103
104static void gfs2_glock_dealloc(struct rcu_head *rcu)
105{
106 struct gfs2_glock *gl = container_of(rcu, struct gfs2_glock, gl_rcu);
107
108 if (gl->gl_ops->go_flags & GLOF_ASPACE)
109 kmem_cache_free(gfs2_glock_aspace_cachep, gl);
110 else
111 kmem_cache_free(gfs2_glock_cachep, gl);
112}
113
114void gfs2_glock_free(struct gfs2_glock *gl)
115{
116 struct gfs2_sbd *sdp = gl->gl_sbd;
117
118 call_rcu(&gl->gl_rcu, gfs2_glock_dealloc);
119 if (atomic_dec_and_test(&sdp->sd_glock_disposal))
120 wake_up(&sdp->sd_glock_wait);
121}
122
123/**
124 * gfs2_glock_hold() - increment reference count on glock
125 * @gl: The glock to hold
126 *
127 */
128
129void gfs2_glock_hold(struct gfs2_glock *gl)
130{
131 GLOCK_BUG_ON(gl, atomic_read(&gl->gl_ref) == 0);
132 atomic_inc(&gl->gl_ref);
133}
134
135/**
136 * demote_ok - Check to see if it's ok to unlock a glock
137 * @gl: the glock
138 *
139 * Returns: 1 if it's ok
140 */
141
142static int demote_ok(const struct gfs2_glock *gl)
143{
144 const struct gfs2_glock_operations *glops = gl->gl_ops;
145
146 if (gl->gl_state == LM_ST_UNLOCKED)
147 return 0;
148 if (!list_empty(&gl->gl_holders))
149 return 0;
150 if (glops->go_demote_ok)
151 return glops->go_demote_ok(gl);
152 return 1;
153}
154
155
156void gfs2_glock_add_to_lru(struct gfs2_glock *gl)
157{
158 spin_lock(&lru_lock);
159
160 if (!list_empty(&gl->gl_lru))
161 list_del_init(&gl->gl_lru);
162 else
163 atomic_inc(&lru_count);
164
165 list_add_tail(&gl->gl_lru, &lru_list);
166 set_bit(GLF_LRU, &gl->gl_flags);
167 spin_unlock(&lru_lock);
168}
169
170static void gfs2_glock_remove_from_lru(struct gfs2_glock *gl)
171{
172 spin_lock(&lru_lock);
173 if (!list_empty(&gl->gl_lru)) {
174 list_del_init(&gl->gl_lru);
175 atomic_dec(&lru_count);
176 clear_bit(GLF_LRU, &gl->gl_flags);
177 }
178 spin_unlock(&lru_lock);
179}
180
181/**
182 * __gfs2_glock_schedule_for_reclaim - Add a glock to the reclaim list
183 * @gl: the glock
184 *
185 * If the glock is demotable, then we add it (or move it) to the end
186 * of the glock LRU list.
187 */
188
189static void __gfs2_glock_schedule_for_reclaim(struct gfs2_glock *gl)
190{
191 if (demote_ok(gl))
192 gfs2_glock_add_to_lru(gl);
193}
194
195/**
196 * gfs2_glock_put_nolock() - Decrement reference count on glock
197 * @gl: The glock to put
198 *
199 * This function should only be used if the caller has its own reference
200 * to the glock, in addition to the one it is dropping.
201 */
202
203void gfs2_glock_put_nolock(struct gfs2_glock *gl)
204{
205 if (atomic_dec_and_test(&gl->gl_ref))
206 GLOCK_BUG_ON(gl, 1);
207}
208
209/**
210 * gfs2_glock_put() - Decrement reference count on glock
211 * @gl: The glock to put
212 *
213 */
214
215void gfs2_glock_put(struct gfs2_glock *gl)
216{
217 struct gfs2_sbd *sdp = gl->gl_sbd;
218 struct address_space *mapping = gfs2_glock2aspace(gl);
219
220 if (atomic_dec_and_test(&gl->gl_ref)) {
221 spin_lock_bucket(gl->gl_hash);
222 hlist_bl_del_rcu(&gl->gl_list);
223 spin_unlock_bucket(gl->gl_hash);
224 gfs2_glock_remove_from_lru(gl);
225 GLOCK_BUG_ON(gl, !list_empty(&gl->gl_holders));
226 GLOCK_BUG_ON(gl, mapping && mapping->nrpages);
227 trace_gfs2_glock_put(gl);
228 sdp->sd_lockstruct.ls_ops->lm_put_lock(gl);
229 }
230}
231
232/**
233 * search_bucket() - Find struct gfs2_glock by lock number
234 * @bucket: the bucket to search
235 * @name: The lock name
236 *
237 * Returns: NULL, or the struct gfs2_glock with the requested number
238 */
239
240static struct gfs2_glock *search_bucket(unsigned int hash,
241 const struct gfs2_sbd *sdp,
242 const struct lm_lockname *name)
243{
244 struct gfs2_glock *gl;
245 struct hlist_bl_node *h;
246
247 hlist_bl_for_each_entry_rcu(gl, h, &gl_hash_table[hash], gl_list) {
248 if (!lm_name_equal(&gl->gl_name, name))
249 continue;
250 if (gl->gl_sbd != sdp)
251 continue;
252 if (atomic_inc_not_zero(&gl->gl_ref))
253 return gl;
254 }
255
256 return NULL;
257}
258
259/**
260 * may_grant - check if its ok to grant a new lock
261 * @gl: The glock
262 * @gh: The lock request which we wish to grant
263 *
264 * Returns: true if its ok to grant the lock
265 */
266
267static inline int may_grant(const struct gfs2_glock *gl, const struct gfs2_holder *gh)
268{
269 const struct gfs2_holder *gh_head = list_entry(gl->gl_holders.next, const struct gfs2_holder, gh_list);
270 if ((gh->gh_state == LM_ST_EXCLUSIVE ||
271 gh_head->gh_state == LM_ST_EXCLUSIVE) && gh != gh_head)
272 return 0;
273 if (gl->gl_state == gh->gh_state)
274 return 1;
275 if (gh->gh_flags & GL_EXACT)
276 return 0;
277 if (gl->gl_state == LM_ST_EXCLUSIVE) {
278 if (gh->gh_state == LM_ST_SHARED && gh_head->gh_state == LM_ST_SHARED)
279 return 1;
280 if (gh->gh_state == LM_ST_DEFERRED && gh_head->gh_state == LM_ST_DEFERRED)
281 return 1;
282 }
283 if (gl->gl_state != LM_ST_UNLOCKED && (gh->gh_flags & LM_FLAG_ANY))
284 return 1;
285 return 0;
286}
287
288static void gfs2_holder_wake(struct gfs2_holder *gh)
289{
290 clear_bit(HIF_WAIT, &gh->gh_iflags);
291 smp_mb__after_clear_bit();
292 wake_up_bit(&gh->gh_iflags, HIF_WAIT);
293}
294
295/**
296 * do_error - Something unexpected has happened during a lock request
297 *
298 */
299
300static inline void do_error(struct gfs2_glock *gl, const int ret)
301{
302 struct gfs2_holder *gh, *tmp;
303
304 list_for_each_entry_safe(gh, tmp, &gl->gl_holders, gh_list) {
305 if (test_bit(HIF_HOLDER, &gh->gh_iflags))
306 continue;
307 if (ret & LM_OUT_ERROR)
308 gh->gh_error = -EIO;
309 else if (gh->gh_flags & (LM_FLAG_TRY | LM_FLAG_TRY_1CB))
310 gh->gh_error = GLR_TRYFAILED;
311 else
312 continue;
313 list_del_init(&gh->gh_list);
314 trace_gfs2_glock_queue(gh, 0);
315 gfs2_holder_wake(gh);
316 }
317}
318
319/**
320 * do_promote - promote as many requests as possible on the current queue
321 * @gl: The glock
322 *
323 * Returns: 1 if there is a blocked holder at the head of the list, or 2
324 * if a type specific operation is underway.
325 */
326
327static int do_promote(struct gfs2_glock *gl)
328__releases(&gl->gl_spin)
329__acquires(&gl->gl_spin)
330{
331 const struct gfs2_glock_operations *glops = gl->gl_ops;
332 struct gfs2_holder *gh, *tmp;
333 int ret;
334
335restart:
336 list_for_each_entry_safe(gh, tmp, &gl->gl_holders, gh_list) {
337 if (test_bit(HIF_HOLDER, &gh->gh_iflags))
338 continue;
339 if (may_grant(gl, gh)) {
340 if (gh->gh_list.prev == &gl->gl_holders &&
341 glops->go_lock) {
342 spin_unlock(&gl->gl_spin);
343 /* FIXME: eliminate this eventually */
344 ret = glops->go_lock(gh);
345 spin_lock(&gl->gl_spin);
346 if (ret) {
347 if (ret == 1)
348 return 2;
349 gh->gh_error = ret;
350 list_del_init(&gh->gh_list);
351 trace_gfs2_glock_queue(gh, 0);
352 gfs2_holder_wake(gh);
353 goto restart;
354 }
355 set_bit(HIF_HOLDER, &gh->gh_iflags);
356 trace_gfs2_promote(gh, 1);
357 gfs2_holder_wake(gh);
358 goto restart;
359 }
360 set_bit(HIF_HOLDER, &gh->gh_iflags);
361 trace_gfs2_promote(gh, 0);
362 gfs2_holder_wake(gh);
363 continue;
364 }
365 if (gh->gh_list.prev == &gl->gl_holders)
366 return 1;
367 do_error(gl, 0);
368 break;
369 }
370 return 0;
371}
372
373/**
374 * find_first_waiter - find the first gh that's waiting for the glock
375 * @gl: the glock
376 */
377
378static inline struct gfs2_holder *find_first_waiter(const struct gfs2_glock *gl)
379{
380 struct gfs2_holder *gh;
381
382 list_for_each_entry(gh, &gl->gl_holders, gh_list) {
383 if (!test_bit(HIF_HOLDER, &gh->gh_iflags))
384 return gh;
385 }
386 return NULL;
387}
388
389/**
390 * state_change - record that the glock is now in a different state
391 * @gl: the glock
392 * @new_state the new state
393 *
394 */
395
396static void state_change(struct gfs2_glock *gl, unsigned int new_state)
397{
398 int held1, held2;
399
400 held1 = (gl->gl_state != LM_ST_UNLOCKED);
401 held2 = (new_state != LM_ST_UNLOCKED);
402
403 if (held1 != held2) {
404 if (held2)
405 gfs2_glock_hold(gl);
406 else
407 gfs2_glock_put_nolock(gl);
408 }
409 if (held1 && held2 && list_empty(&gl->gl_holders))
410 clear_bit(GLF_QUEUED, &gl->gl_flags);
411
412 if (new_state != gl->gl_target)
413 /* shorten our minimum hold time */
414 gl->gl_hold_time = max(gl->gl_hold_time - GL_GLOCK_HOLD_DECR,
415 GL_GLOCK_MIN_HOLD);
416 gl->gl_state = new_state;
417 gl->gl_tchange = jiffies;
418}
419
420static void gfs2_demote_wake(struct gfs2_glock *gl)
421{
422 gl->gl_demote_state = LM_ST_EXCLUSIVE;
423 clear_bit(GLF_DEMOTE, &gl->gl_flags);
424 smp_mb__after_clear_bit();
425 wake_up_bit(&gl->gl_flags, GLF_DEMOTE);
426}
427
428/**
429 * finish_xmote - The DLM has replied to one of our lock requests
430 * @gl: The glock
431 * @ret: The status from the DLM
432 *
433 */
434
435static void finish_xmote(struct gfs2_glock *gl, unsigned int ret)
436{
437 const struct gfs2_glock_operations *glops = gl->gl_ops;
438 struct gfs2_holder *gh;
439 unsigned state = ret & LM_OUT_ST_MASK;
440 int rv;
441
442 spin_lock(&gl->gl_spin);
443 trace_gfs2_glock_state_change(gl, state);
444 state_change(gl, state);
445 gh = find_first_waiter(gl);
446
447 /* Demote to UN request arrived during demote to SH or DF */
448 if (test_bit(GLF_DEMOTE_IN_PROGRESS, &gl->gl_flags) &&
449 state != LM_ST_UNLOCKED && gl->gl_demote_state == LM_ST_UNLOCKED)
450 gl->gl_target = LM_ST_UNLOCKED;
451
452 /* Check for state != intended state */
453 if (unlikely(state != gl->gl_target)) {
454 if (gh && !test_bit(GLF_DEMOTE_IN_PROGRESS, &gl->gl_flags)) {
455 /* move to back of queue and try next entry */
456 if (ret & LM_OUT_CANCELED) {
457 if ((gh->gh_flags & LM_FLAG_PRIORITY) == 0)
458 list_move_tail(&gh->gh_list, &gl->gl_holders);
459 gh = find_first_waiter(gl);
460 gl->gl_target = gh->gh_state;
461 goto retry;
462 }
463 /* Some error or failed "try lock" - report it */
464 if ((ret & LM_OUT_ERROR) ||
465 (gh->gh_flags & (LM_FLAG_TRY | LM_FLAG_TRY_1CB))) {
466 gl->gl_target = gl->gl_state;
467 do_error(gl, ret);
468 goto out;
469 }
470 }
471 switch(state) {
472 /* Unlocked due to conversion deadlock, try again */
473 case LM_ST_UNLOCKED:
474retry:
475 do_xmote(gl, gh, gl->gl_target);
476 break;
477 /* Conversion fails, unlock and try again */
478 case LM_ST_SHARED:
479 case LM_ST_DEFERRED:
480 do_xmote(gl, gh, LM_ST_UNLOCKED);
481 break;
482 default: /* Everything else */
483 printk(KERN_ERR "GFS2: wanted %u got %u\n", gl->gl_target, state);
484 GLOCK_BUG_ON(gl, 1);
485 }
486 spin_unlock(&gl->gl_spin);
487 return;
488 }
489
490 /* Fast path - we got what we asked for */
491 if (test_and_clear_bit(GLF_DEMOTE_IN_PROGRESS, &gl->gl_flags))
492 gfs2_demote_wake(gl);
493 if (state != LM_ST_UNLOCKED) {
494 if (glops->go_xmote_bh) {
495 spin_unlock(&gl->gl_spin);
496 rv = glops->go_xmote_bh(gl, gh);
497 spin_lock(&gl->gl_spin);
498 if (rv) {
499 do_error(gl, rv);
500 goto out;
501 }
502 }
503 rv = do_promote(gl);
504 if (rv == 2)
505 goto out_locked;
506 }
507out:
508 clear_bit(GLF_LOCK, &gl->gl_flags);
509out_locked:
510 spin_unlock(&gl->gl_spin);
511}
512
513/**
514 * do_xmote - Calls the DLM to change the state of a lock
515 * @gl: The lock state
516 * @gh: The holder (only for promotes)
517 * @target: The target lock state
518 *
519 */
520
521static void do_xmote(struct gfs2_glock *gl, struct gfs2_holder *gh, unsigned int target)
522__releases(&gl->gl_spin)
523__acquires(&gl->gl_spin)
524{
525 const struct gfs2_glock_operations *glops = gl->gl_ops;
526 struct gfs2_sbd *sdp = gl->gl_sbd;
527 unsigned int lck_flags = gh ? gh->gh_flags : 0;
528 int ret;
529
530 lck_flags &= (LM_FLAG_TRY | LM_FLAG_TRY_1CB | LM_FLAG_NOEXP |
531 LM_FLAG_PRIORITY);
532 GLOCK_BUG_ON(gl, gl->gl_state == target);
533 GLOCK_BUG_ON(gl, gl->gl_state == gl->gl_target);
534 if ((target == LM_ST_UNLOCKED || target == LM_ST_DEFERRED) &&
535 glops->go_inval) {
536 set_bit(GLF_INVALIDATE_IN_PROGRESS, &gl->gl_flags);
537 do_error(gl, 0); /* Fail queued try locks */
538 }
539 gl->gl_req = target;
540 spin_unlock(&gl->gl_spin);
541 if (glops->go_xmote_th)
542 glops->go_xmote_th(gl);
543 if (test_bit(GLF_INVALIDATE_IN_PROGRESS, &gl->gl_flags))
544 glops->go_inval(gl, target == LM_ST_DEFERRED ? 0 : DIO_METADATA);
545 clear_bit(GLF_INVALIDATE_IN_PROGRESS, &gl->gl_flags);
546
547 gfs2_glock_hold(gl);
548 if (sdp->sd_lockstruct.ls_ops->lm_lock) {
549 /* lock_dlm */
550 ret = sdp->sd_lockstruct.ls_ops->lm_lock(gl, target, lck_flags);
551 GLOCK_BUG_ON(gl, ret);
552 } else { /* lock_nolock */
553 finish_xmote(gl, target);
554 if (queue_delayed_work(glock_workqueue, &gl->gl_work, 0) == 0)
555 gfs2_glock_put(gl);
556 }
557
558 spin_lock(&gl->gl_spin);
559}
560
561/**
562 * find_first_holder - find the first "holder" gh
563 * @gl: the glock
564 */
565
566static inline struct gfs2_holder *find_first_holder(const struct gfs2_glock *gl)
567{
568 struct gfs2_holder *gh;
569
570 if (!list_empty(&gl->gl_holders)) {
571 gh = list_entry(gl->gl_holders.next, struct gfs2_holder, gh_list);
572 if (test_bit(HIF_HOLDER, &gh->gh_iflags))
573 return gh;
574 }
575 return NULL;
576}
577
578/**
579 * run_queue - do all outstanding tasks related to a glock
580 * @gl: The glock in question
581 * @nonblock: True if we must not block in run_queue
582 *
583 */
584
585static void run_queue(struct gfs2_glock *gl, const int nonblock)
586__releases(&gl->gl_spin)
587__acquires(&gl->gl_spin)
588{
589 struct gfs2_holder *gh = NULL;
590 int ret;
591
592 if (test_and_set_bit(GLF_LOCK, &gl->gl_flags))
593 return;
594
595 GLOCK_BUG_ON(gl, test_bit(GLF_DEMOTE_IN_PROGRESS, &gl->gl_flags));
596
597 if (test_bit(GLF_DEMOTE, &gl->gl_flags) &&
598 gl->gl_demote_state != gl->gl_state) {
599 if (find_first_holder(gl))
600 goto out_unlock;
601 if (nonblock)
602 goto out_sched;
603 set_bit(GLF_DEMOTE_IN_PROGRESS, &gl->gl_flags);
604 GLOCK_BUG_ON(gl, gl->gl_demote_state == LM_ST_EXCLUSIVE);
605 gl->gl_target = gl->gl_demote_state;
606 } else {
607 if (test_bit(GLF_DEMOTE, &gl->gl_flags))
608 gfs2_demote_wake(gl);
609 ret = do_promote(gl);
610 if (ret == 0)
611 goto out_unlock;
612 if (ret == 2)
613 goto out;
614 gh = find_first_waiter(gl);
615 gl->gl_target = gh->gh_state;
616 if (!(gh->gh_flags & (LM_FLAG_TRY | LM_FLAG_TRY_1CB)))
617 do_error(gl, 0); /* Fail queued try locks */
618 }
619 do_xmote(gl, gh, gl->gl_target);
620out:
621 return;
622
623out_sched:
624 clear_bit(GLF_LOCK, &gl->gl_flags);
625 smp_mb__after_clear_bit();
626 gfs2_glock_hold(gl);
627 if (queue_delayed_work(glock_workqueue, &gl->gl_work, 0) == 0)
628 gfs2_glock_put_nolock(gl);
629 return;
630
631out_unlock:
632 clear_bit(GLF_LOCK, &gl->gl_flags);
633 smp_mb__after_clear_bit();
634 return;
635}
636
637static void delete_work_func(struct work_struct *work)
638{
639 struct gfs2_glock *gl = container_of(work, struct gfs2_glock, gl_delete);
640 struct gfs2_sbd *sdp = gl->gl_sbd;
641 struct gfs2_inode *ip;
642 struct inode *inode;
643 u64 no_addr = gl->gl_name.ln_number;
644
645 ip = gl->gl_object;
646 /* Note: Unsafe to dereference ip as we don't hold right refs/locks */
647
648 if (ip)
649 inode = gfs2_ilookup(sdp->sd_vfs, no_addr, 1);
650 else
651 inode = gfs2_lookup_by_inum(sdp, no_addr, NULL, GFS2_BLKST_UNLINKED);
652 if (inode && !IS_ERR(inode)) {
653 d_prune_aliases(inode);
654 iput(inode);
655 }
656 gfs2_glock_put(gl);
657}
658
659static void glock_work_func(struct work_struct *work)
660{
661 unsigned long delay = 0;
662 struct gfs2_glock *gl = container_of(work, struct gfs2_glock, gl_work.work);
663 int drop_ref = 0;
664
665 if (test_and_clear_bit(GLF_REPLY_PENDING, &gl->gl_flags)) {
666 finish_xmote(gl, gl->gl_reply);
667 drop_ref = 1;
668 }
669 spin_lock(&gl->gl_spin);
670 if (test_bit(GLF_PENDING_DEMOTE, &gl->gl_flags) &&
671 gl->gl_state != LM_ST_UNLOCKED &&
672 gl->gl_demote_state != LM_ST_EXCLUSIVE) {
673 unsigned long holdtime, now = jiffies;
674
675 holdtime = gl->gl_tchange + gl->gl_hold_time;
676 if (time_before(now, holdtime))
677 delay = holdtime - now;
678
679 if (!delay) {
680 clear_bit(GLF_PENDING_DEMOTE, &gl->gl_flags);
681 set_bit(GLF_DEMOTE, &gl->gl_flags);
682 }
683 }
684 run_queue(gl, 0);
685 spin_unlock(&gl->gl_spin);
686 if (!delay)
687 gfs2_glock_put(gl);
688 else {
689 if (gl->gl_name.ln_type != LM_TYPE_INODE)
690 delay = 0;
691 if (queue_delayed_work(glock_workqueue, &gl->gl_work, delay) == 0)
692 gfs2_glock_put(gl);
693 }
694 if (drop_ref)
695 gfs2_glock_put(gl);
696}
697
698/**
699 * gfs2_glock_get() - Get a glock, or create one if one doesn't exist
700 * @sdp: The GFS2 superblock
701 * @number: the lock number
702 * @glops: The glock_operations to use
703 * @create: If 0, don't create the glock if it doesn't exist
704 * @glp: the glock is returned here
705 *
706 * This does not lock a glock, just finds/creates structures for one.
707 *
708 * Returns: errno
709 */
710
711int gfs2_glock_get(struct gfs2_sbd *sdp, u64 number,
712 const struct gfs2_glock_operations *glops, int create,
713 struct gfs2_glock **glp)
714{
715 struct super_block *s = sdp->sd_vfs;
716 struct lm_lockname name = { .ln_number = number, .ln_type = glops->go_type };
717 struct gfs2_glock *gl, *tmp;
718 unsigned int hash = gl_hash(sdp, &name);
719 struct address_space *mapping;
720 struct kmem_cache *cachep;
721
722 rcu_read_lock();
723 gl = search_bucket(hash, sdp, &name);
724 rcu_read_unlock();
725
726 *glp = gl;
727 if (gl)
728 return 0;
729 if (!create)
730 return -ENOENT;
731
732 if (glops->go_flags & GLOF_ASPACE)
733 cachep = gfs2_glock_aspace_cachep;
734 else
735 cachep = gfs2_glock_cachep;
736 gl = kmem_cache_alloc(cachep, GFP_KERNEL);
737 if (!gl)
738 return -ENOMEM;
739
740 atomic_inc(&sdp->sd_glock_disposal);
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 snprintf(gl->gl_strname, GDLM_STRNAME_BYTES, "%8x%16llx", name.ln_type, (unsigned long long)number);
750 memset(&gl->gl_lksb, 0, sizeof(struct dlm_lksb));
751 gl->gl_lksb.sb_lvbptr = gl->gl_lvb;
752 gl->gl_tchange = jiffies;
753 gl->gl_object = NULL;
754 gl->gl_sbd = sdp;
755 gl->gl_hold_time = GL_GLOCK_DFT_HOLD;
756 INIT_DELAYED_WORK(&gl->gl_work, glock_work_func);
757 INIT_WORK(&gl->gl_delete, delete_work_func);
758
759 mapping = gfs2_glock2aspace(gl);
760 if (mapping) {
761 mapping->a_ops = &gfs2_meta_aops;
762 mapping->host = s->s_bdev->bd_inode;
763 mapping->flags = 0;
764 mapping_set_gfp_mask(mapping, GFP_NOFS);
765 mapping->assoc_mapping = NULL;
766 mapping->backing_dev_info = s->s_bdi;
767 mapping->writeback_index = 0;
768 }
769
770 spin_lock_bucket(hash);
771 tmp = search_bucket(hash, sdp, &name);
772 if (tmp) {
773 spin_unlock_bucket(hash);
774 kmem_cache_free(cachep, gl);
775 atomic_dec(&sdp->sd_glock_disposal);
776 gl = tmp;
777 } else {
778 hlist_bl_add_head_rcu(&gl->gl_list, &gl_hash_table[hash]);
779 spin_unlock_bucket(hash);
780 }
781
782 *glp = gl;
783
784 return 0;
785}
786
787/**
788 * gfs2_holder_init - initialize a struct gfs2_holder in the default way
789 * @gl: the glock
790 * @state: the state we're requesting
791 * @flags: the modifier flags
792 * @gh: the holder structure
793 *
794 */
795
796void gfs2_holder_init(struct gfs2_glock *gl, unsigned int state, unsigned flags,
797 struct gfs2_holder *gh)
798{
799 INIT_LIST_HEAD(&gh->gh_list);
800 gh->gh_gl = gl;
801 gh->gh_ip = (unsigned long)__builtin_return_address(0);
802 gh->gh_owner_pid = get_pid(task_pid(current));
803 gh->gh_state = state;
804 gh->gh_flags = flags;
805 gh->gh_error = 0;
806 gh->gh_iflags = 0;
807 gfs2_glock_hold(gl);
808}
809
810/**
811 * gfs2_holder_reinit - reinitialize a struct gfs2_holder so we can requeue it
812 * @state: the state we're requesting
813 * @flags: the modifier flags
814 * @gh: the holder structure
815 *
816 * Don't mess with the glock.
817 *
818 */
819
820void gfs2_holder_reinit(unsigned int state, unsigned flags, struct gfs2_holder *gh)
821{
822 gh->gh_state = state;
823 gh->gh_flags = flags;
824 gh->gh_iflags = 0;
825 gh->gh_ip = (unsigned long)__builtin_return_address(0);
826 if (gh->gh_owner_pid)
827 put_pid(gh->gh_owner_pid);
828 gh->gh_owner_pid = get_pid(task_pid(current));
829}
830
831/**
832 * gfs2_holder_uninit - uninitialize a holder structure (drop glock reference)
833 * @gh: the holder structure
834 *
835 */
836
837void gfs2_holder_uninit(struct gfs2_holder *gh)
838{
839 put_pid(gh->gh_owner_pid);
840 gfs2_glock_put(gh->gh_gl);
841 gh->gh_gl = NULL;
842 gh->gh_ip = 0;
843}
844
845/**
846 * gfs2_glock_holder_wait
847 * @word: unused
848 *
849 * This function and gfs2_glock_demote_wait both show up in the WCHAN
850 * field. Thus I've separated these otherwise identical functions in
851 * order to be more informative to the user.
852 */
853
854static int gfs2_glock_holder_wait(void *word)
855{
856 schedule();
857 return 0;
858}
859
860static int gfs2_glock_demote_wait(void *word)
861{
862 schedule();
863 return 0;
864}
865
866static void wait_on_holder(struct gfs2_holder *gh)
867{
868 unsigned long time1 = jiffies;
869
870 might_sleep();
871 wait_on_bit(&gh->gh_iflags, HIF_WAIT, gfs2_glock_holder_wait, TASK_UNINTERRUPTIBLE);
872 if (time_after(jiffies, time1 + HZ)) /* have we waited > a second? */
873 /* Lengthen the minimum hold time. */
874 gh->gh_gl->gl_hold_time = min(gh->gh_gl->gl_hold_time +
875 GL_GLOCK_HOLD_INCR,
876 GL_GLOCK_MAX_HOLD);
877}
878
879static void wait_on_demote(struct gfs2_glock *gl)
880{
881 might_sleep();
882 wait_on_bit(&gl->gl_flags, GLF_DEMOTE, gfs2_glock_demote_wait, TASK_UNINTERRUPTIBLE);
883}
884
885/**
886 * handle_callback - process a demote request
887 * @gl: the glock
888 * @state: the state the caller wants us to change to
889 *
890 * There are only two requests that we are going to see in actual
891 * practise: LM_ST_SHARED and LM_ST_UNLOCKED
892 */
893
894static void handle_callback(struct gfs2_glock *gl, unsigned int state,
895 unsigned long delay)
896{
897 int bit = delay ? GLF_PENDING_DEMOTE : GLF_DEMOTE;
898
899 set_bit(bit, &gl->gl_flags);
900 if (gl->gl_demote_state == LM_ST_EXCLUSIVE) {
901 gl->gl_demote_state = state;
902 gl->gl_demote_time = jiffies;
903 } else if (gl->gl_demote_state != LM_ST_UNLOCKED &&
904 gl->gl_demote_state != state) {
905 gl->gl_demote_state = LM_ST_UNLOCKED;
906 }
907 if (gl->gl_ops->go_callback)
908 gl->gl_ops->go_callback(gl);
909 trace_gfs2_demote_rq(gl);
910}
911
912/**
913 * gfs2_glock_wait - wait on a glock acquisition
914 * @gh: the glock holder
915 *
916 * Returns: 0 on success
917 */
918
919int gfs2_glock_wait(struct gfs2_holder *gh)
920{
921 wait_on_holder(gh);
922 return gh->gh_error;
923}
924
925void gfs2_print_dbg(struct seq_file *seq, const char *fmt, ...)
926{
927 struct va_format vaf;
928 va_list args;
929
930 va_start(args, fmt);
931
932 if (seq) {
933 struct gfs2_glock_iter *gi = seq->private;
934 vsprintf(gi->string, fmt, args);
935 seq_printf(seq, gi->string);
936 } else {
937 vaf.fmt = fmt;
938 vaf.va = &args;
939
940 printk(KERN_ERR " %pV", &vaf);
941 }
942
943 va_end(args);
944}
945
946/**
947 * add_to_queue - Add a holder to the wait queue (but look for recursion)
948 * @gh: the holder structure to add
949 *
950 * Eventually we should move the recursive locking trap to a
951 * debugging option or something like that. This is the fast
952 * path and needs to have the minimum number of distractions.
953 *
954 */
955
956static inline void add_to_queue(struct gfs2_holder *gh)
957__releases(&gl->gl_spin)
958__acquires(&gl->gl_spin)
959{
960 struct gfs2_glock *gl = gh->gh_gl;
961 struct gfs2_sbd *sdp = gl->gl_sbd;
962 struct list_head *insert_pt = NULL;
963 struct gfs2_holder *gh2;
964 int try_lock = 0;
965
966 BUG_ON(gh->gh_owner_pid == NULL);
967 if (test_and_set_bit(HIF_WAIT, &gh->gh_iflags))
968 BUG();
969
970 if (gh->gh_flags & (LM_FLAG_TRY | LM_FLAG_TRY_1CB)) {
971 if (test_bit(GLF_LOCK, &gl->gl_flags))
972 try_lock = 1;
973 if (test_bit(GLF_INVALIDATE_IN_PROGRESS, &gl->gl_flags))
974 goto fail;
975 }
976
977 list_for_each_entry(gh2, &gl->gl_holders, gh_list) {
978 if (unlikely(gh2->gh_owner_pid == gh->gh_owner_pid &&
979 (gh->gh_gl->gl_ops->go_type != LM_TYPE_FLOCK)))
980 goto trap_recursive;
981 if (try_lock &&
982 !(gh2->gh_flags & (LM_FLAG_TRY | LM_FLAG_TRY_1CB)) &&
983 !may_grant(gl, gh)) {
984fail:
985 gh->gh_error = GLR_TRYFAILED;
986 gfs2_holder_wake(gh);
987 return;
988 }
989 if (test_bit(HIF_HOLDER, &gh2->gh_iflags))
990 continue;
991 if (unlikely((gh->gh_flags & LM_FLAG_PRIORITY) && !insert_pt))
992 insert_pt = &gh2->gh_list;
993 }
994 set_bit(GLF_QUEUED, &gl->gl_flags);
995 trace_gfs2_glock_queue(gh, 1);
996 if (likely(insert_pt == NULL)) {
997 list_add_tail(&gh->gh_list, &gl->gl_holders);
998 if (unlikely(gh->gh_flags & LM_FLAG_PRIORITY))
999 goto do_cancel;
1000 return;
1001 }
1002 list_add_tail(&gh->gh_list, insert_pt);
1003do_cancel:
1004 gh = list_entry(gl->gl_holders.next, struct gfs2_holder, gh_list);
1005 if (!(gh->gh_flags & LM_FLAG_PRIORITY)) {
1006 spin_unlock(&gl->gl_spin);
1007 if (sdp->sd_lockstruct.ls_ops->lm_cancel)
1008 sdp->sd_lockstruct.ls_ops->lm_cancel(gl);
1009 spin_lock(&gl->gl_spin);
1010 }
1011 return;
1012
1013trap_recursive:
1014 print_symbol(KERN_ERR "original: %s\n", gh2->gh_ip);
1015 printk(KERN_ERR "pid: %d\n", pid_nr(gh2->gh_owner_pid));
1016 printk(KERN_ERR "lock type: %d req lock state : %d\n",
1017 gh2->gh_gl->gl_name.ln_type, gh2->gh_state);
1018 print_symbol(KERN_ERR "new: %s\n", gh->gh_ip);
1019 printk(KERN_ERR "pid: %d\n", pid_nr(gh->gh_owner_pid));
1020 printk(KERN_ERR "lock type: %d req lock state : %d\n",
1021 gh->gh_gl->gl_name.ln_type, gh->gh_state);
1022 __dump_glock(NULL, gl);
1023 BUG();
1024}
1025
1026/**
1027 * gfs2_glock_nq - enqueue a struct gfs2_holder onto a glock (acquire a glock)
1028 * @gh: the holder structure
1029 *
1030 * if (gh->gh_flags & GL_ASYNC), this never returns an error
1031 *
1032 * Returns: 0, GLR_TRYFAILED, or errno on failure
1033 */
1034
1035int gfs2_glock_nq(struct gfs2_holder *gh)
1036{
1037 struct gfs2_glock *gl = gh->gh_gl;
1038 struct gfs2_sbd *sdp = gl->gl_sbd;
1039 int error = 0;
1040
1041 if (unlikely(test_bit(SDF_SHUTDOWN, &sdp->sd_flags)))
1042 return -EIO;
1043
1044 if (test_bit(GLF_LRU, &gl->gl_flags))
1045 gfs2_glock_remove_from_lru(gl);
1046
1047 spin_lock(&gl->gl_spin);
1048 add_to_queue(gh);
1049 if ((LM_FLAG_NOEXP & gh->gh_flags) &&
1050 test_and_clear_bit(GLF_FROZEN, &gl->gl_flags))
1051 set_bit(GLF_REPLY_PENDING, &gl->gl_flags);
1052 run_queue(gl, 1);
1053 spin_unlock(&gl->gl_spin);
1054
1055 if (!(gh->gh_flags & GL_ASYNC))
1056 error = gfs2_glock_wait(gh);
1057
1058 return error;
1059}
1060
1061/**
1062 * gfs2_glock_poll - poll to see if an async request has been completed
1063 * @gh: the holder
1064 *
1065 * Returns: 1 if the request is ready to be gfs2_glock_wait()ed on
1066 */
1067
1068int gfs2_glock_poll(struct gfs2_holder *gh)
1069{
1070 return test_bit(HIF_WAIT, &gh->gh_iflags) ? 0 : 1;
1071}
1072
1073/**
1074 * gfs2_glock_dq - dequeue a struct gfs2_holder from a glock (release a glock)
1075 * @gh: the glock holder
1076 *
1077 */
1078
1079void gfs2_glock_dq(struct gfs2_holder *gh)
1080{
1081 struct gfs2_glock *gl = gh->gh_gl;
1082 const struct gfs2_glock_operations *glops = gl->gl_ops;
1083 unsigned delay = 0;
1084 int fast_path = 0;
1085
1086 spin_lock(&gl->gl_spin);
1087 if (gh->gh_flags & GL_NOCACHE)
1088 handle_callback(gl, LM_ST_UNLOCKED, 0);
1089
1090 list_del_init(&gh->gh_list);
1091 if (find_first_holder(gl) == NULL) {
1092 if (glops->go_unlock) {
1093 GLOCK_BUG_ON(gl, test_and_set_bit(GLF_LOCK, &gl->gl_flags));
1094 spin_unlock(&gl->gl_spin);
1095 glops->go_unlock(gh);
1096 spin_lock(&gl->gl_spin);
1097 clear_bit(GLF_LOCK, &gl->gl_flags);
1098 }
1099 if (list_empty(&gl->gl_holders) &&
1100 !test_bit(GLF_PENDING_DEMOTE, &gl->gl_flags) &&
1101 !test_bit(GLF_DEMOTE, &gl->gl_flags))
1102 fast_path = 1;
1103 }
1104 if (!test_bit(GLF_LFLUSH, &gl->gl_flags))
1105 __gfs2_glock_schedule_for_reclaim(gl);
1106 trace_gfs2_glock_queue(gh, 0);
1107 spin_unlock(&gl->gl_spin);
1108 if (likely(fast_path))
1109 return;
1110
1111 gfs2_glock_hold(gl);
1112 if (test_bit(GLF_PENDING_DEMOTE, &gl->gl_flags) &&
1113 !test_bit(GLF_DEMOTE, &gl->gl_flags) &&
1114 gl->gl_name.ln_type == LM_TYPE_INODE)
1115 delay = gl->gl_hold_time;
1116 if (queue_delayed_work(glock_workqueue, &gl->gl_work, delay) == 0)
1117 gfs2_glock_put(gl);
1118}
1119
1120void gfs2_glock_dq_wait(struct gfs2_holder *gh)
1121{
1122 struct gfs2_glock *gl = gh->gh_gl;
1123 gfs2_glock_dq(gh);
1124 wait_on_demote(gl);
1125}
1126
1127/**
1128 * gfs2_glock_dq_uninit - dequeue a holder from a glock and initialize it
1129 * @gh: the holder structure
1130 *
1131 */
1132
1133void gfs2_glock_dq_uninit(struct gfs2_holder *gh)
1134{
1135 gfs2_glock_dq(gh);
1136 gfs2_holder_uninit(gh);
1137}
1138
1139/**
1140 * gfs2_glock_nq_num - acquire a glock based on lock number
1141 * @sdp: the filesystem
1142 * @number: the lock number
1143 * @glops: the glock operations for the type of glock
1144 * @state: the state to acquire the glock in
1145 * @flags: modifier flags for the acquisition
1146 * @gh: the struct gfs2_holder
1147 *
1148 * Returns: errno
1149 */
1150
1151int gfs2_glock_nq_num(struct gfs2_sbd *sdp, u64 number,
1152 const struct gfs2_glock_operations *glops,
1153 unsigned int state, int flags, struct gfs2_holder *gh)
1154{
1155 struct gfs2_glock *gl;
1156 int error;
1157
1158 error = gfs2_glock_get(sdp, number, glops, CREATE, &gl);
1159 if (!error) {
1160 error = gfs2_glock_nq_init(gl, state, flags, gh);
1161 gfs2_glock_put(gl);
1162 }
1163
1164 return error;
1165}
1166
1167/**
1168 * glock_compare - Compare two struct gfs2_glock structures for sorting
1169 * @arg_a: the first structure
1170 * @arg_b: the second structure
1171 *
1172 */
1173
1174static int glock_compare(const void *arg_a, const void *arg_b)
1175{
1176 const struct gfs2_holder *gh_a = *(const struct gfs2_holder **)arg_a;
1177 const struct gfs2_holder *gh_b = *(const struct gfs2_holder **)arg_b;
1178 const struct lm_lockname *a = &gh_a->gh_gl->gl_name;
1179 const struct lm_lockname *b = &gh_b->gh_gl->gl_name;
1180
1181 if (a->ln_number > b->ln_number)
1182 return 1;
1183 if (a->ln_number < b->ln_number)
1184 return -1;
1185 BUG_ON(gh_a->gh_gl->gl_ops->go_type == gh_b->gh_gl->gl_ops->go_type);
1186 return 0;
1187}
1188
1189/**
1190 * nq_m_sync - synchonously acquire more than one glock in deadlock free order
1191 * @num_gh: the number of structures
1192 * @ghs: an array of struct gfs2_holder structures
1193 *
1194 * Returns: 0 on success (all glocks acquired),
1195 * errno on failure (no glocks acquired)
1196 */
1197
1198static int nq_m_sync(unsigned int num_gh, struct gfs2_holder *ghs,
1199 struct gfs2_holder **p)
1200{
1201 unsigned int x;
1202 int error = 0;
1203
1204 for (x = 0; x < num_gh; x++)
1205 p[x] = &ghs[x];
1206
1207 sort(p, num_gh, sizeof(struct gfs2_holder *), glock_compare, NULL);
1208
1209 for (x = 0; x < num_gh; x++) {
1210 p[x]->gh_flags &= ~(LM_FLAG_TRY | GL_ASYNC);
1211
1212 error = gfs2_glock_nq(p[x]);
1213 if (error) {
1214 while (x--)
1215 gfs2_glock_dq(p[x]);
1216 break;
1217 }
1218 }
1219
1220 return error;
1221}
1222
1223/**
1224 * gfs2_glock_nq_m - acquire multiple glocks
1225 * @num_gh: the number of structures
1226 * @ghs: an array of struct gfs2_holder structures
1227 *
1228 *
1229 * Returns: 0 on success (all glocks acquired),
1230 * errno on failure (no glocks acquired)
1231 */
1232
1233int gfs2_glock_nq_m(unsigned int num_gh, struct gfs2_holder *ghs)
1234{
1235 struct gfs2_holder *tmp[4];
1236 struct gfs2_holder **pph = tmp;
1237 int error = 0;
1238
1239 switch(num_gh) {
1240 case 0:
1241 return 0;
1242 case 1:
1243 ghs->gh_flags &= ~(LM_FLAG_TRY | GL_ASYNC);
1244 return gfs2_glock_nq(ghs);
1245 default:
1246 if (num_gh <= 4)
1247 break;
1248 pph = kmalloc(num_gh * sizeof(struct gfs2_holder *), GFP_NOFS);
1249 if (!pph)
1250 return -ENOMEM;
1251 }
1252
1253 error = nq_m_sync(num_gh, ghs, pph);
1254
1255 if (pph != tmp)
1256 kfree(pph);
1257
1258 return error;
1259}
1260
1261/**
1262 * gfs2_glock_dq_m - release multiple glocks
1263 * @num_gh: the number of structures
1264 * @ghs: an array of struct gfs2_holder structures
1265 *
1266 */
1267
1268void gfs2_glock_dq_m(unsigned int num_gh, struct gfs2_holder *ghs)
1269{
1270 while (num_gh--)
1271 gfs2_glock_dq(&ghs[num_gh]);
1272}
1273
1274/**
1275 * gfs2_glock_dq_uninit_m - release multiple glocks
1276 * @num_gh: the number of structures
1277 * @ghs: an array of struct gfs2_holder structures
1278 *
1279 */
1280
1281void gfs2_glock_dq_uninit_m(unsigned int num_gh, struct gfs2_holder *ghs)
1282{
1283 while (num_gh--)
1284 gfs2_glock_dq_uninit(&ghs[num_gh]);
1285}
1286
1287void gfs2_glock_cb(struct gfs2_glock *gl, unsigned int state)
1288{
1289 unsigned long delay = 0;
1290 unsigned long holdtime;
1291 unsigned long now = jiffies;
1292
1293 gfs2_glock_hold(gl);
1294 holdtime = gl->gl_tchange + gl->gl_hold_time;
1295 if (test_bit(GLF_QUEUED, &gl->gl_flags) &&
1296 gl->gl_name.ln_type == LM_TYPE_INODE) {
1297 if (time_before(now, holdtime))
1298 delay = holdtime - now;
1299 if (test_bit(GLF_REPLY_PENDING, &gl->gl_flags))
1300 delay = gl->gl_hold_time;
1301 }
1302
1303 spin_lock(&gl->gl_spin);
1304 handle_callback(gl, state, delay);
1305 spin_unlock(&gl->gl_spin);
1306 if (queue_delayed_work(glock_workqueue, &gl->gl_work, delay) == 0)
1307 gfs2_glock_put(gl);
1308}
1309
1310/**
1311 * gfs2_should_freeze - Figure out if glock should be frozen
1312 * @gl: The glock in question
1313 *
1314 * Glocks are not frozen if (a) the result of the dlm operation is
1315 * an error, (b) the locking operation was an unlock operation or
1316 * (c) if there is a "noexp" flagged request anywhere in the queue
1317 *
1318 * Returns: 1 if freezing should occur, 0 otherwise
1319 */
1320
1321static int gfs2_should_freeze(const struct gfs2_glock *gl)
1322{
1323 const struct gfs2_holder *gh;
1324
1325 if (gl->gl_reply & ~LM_OUT_ST_MASK)
1326 return 0;
1327 if (gl->gl_target == LM_ST_UNLOCKED)
1328 return 0;
1329
1330 list_for_each_entry(gh, &gl->gl_holders, gh_list) {
1331 if (test_bit(HIF_HOLDER, &gh->gh_iflags))
1332 continue;
1333 if (LM_FLAG_NOEXP & gh->gh_flags)
1334 return 0;
1335 }
1336
1337 return 1;
1338}
1339
1340/**
1341 * gfs2_glock_complete - Callback used by locking
1342 * @gl: Pointer to the glock
1343 * @ret: The return value from the dlm
1344 *
1345 * The gl_reply field is under the gl_spin lock so that it is ok
1346 * to use a bitfield shared with other glock state fields.
1347 */
1348
1349void gfs2_glock_complete(struct gfs2_glock *gl, int ret)
1350{
1351 struct lm_lockstruct *ls = &gl->gl_sbd->sd_lockstruct;
1352
1353 spin_lock(&gl->gl_spin);
1354 gl->gl_reply = ret;
1355
1356 if (unlikely(test_bit(DFL_BLOCK_LOCKS, &ls->ls_flags))) {
1357 if (gfs2_should_freeze(gl)) {
1358 set_bit(GLF_FROZEN, &gl->gl_flags);
1359 spin_unlock(&gl->gl_spin);
1360 return;
1361 }
1362 }
1363
1364 spin_unlock(&gl->gl_spin);
1365 set_bit(GLF_REPLY_PENDING, &gl->gl_flags);
1366 smp_wmb();
1367 gfs2_glock_hold(gl);
1368 if (queue_delayed_work(glock_workqueue, &gl->gl_work, 0) == 0)
1369 gfs2_glock_put(gl);
1370}
1371
1372
1373static int gfs2_shrink_glock_memory(struct shrinker *shrink,
1374 struct shrink_control *sc)
1375{
1376 struct gfs2_glock *gl;
1377 int may_demote;
1378 int nr_skipped = 0;
1379 int nr = sc->nr_to_scan;
1380 gfp_t gfp_mask = sc->gfp_mask;
1381 LIST_HEAD(skipped);
1382
1383 if (nr == 0)
1384 goto out;
1385
1386 if (!(gfp_mask & __GFP_FS))
1387 return -1;
1388
1389 spin_lock(&lru_lock);
1390 while(nr && !list_empty(&lru_list)) {
1391 gl = list_entry(lru_list.next, struct gfs2_glock, gl_lru);
1392 list_del_init(&gl->gl_lru);
1393 clear_bit(GLF_LRU, &gl->gl_flags);
1394 atomic_dec(&lru_count);
1395
1396 /* Test for being demotable */
1397 if (!test_and_set_bit(GLF_LOCK, &gl->gl_flags)) {
1398 gfs2_glock_hold(gl);
1399 spin_unlock(&lru_lock);
1400 spin_lock(&gl->gl_spin);
1401 may_demote = demote_ok(gl);
1402 if (may_demote) {
1403 handle_callback(gl, LM_ST_UNLOCKED, 0);
1404 nr--;
1405 }
1406 clear_bit(GLF_LOCK, &gl->gl_flags);
1407 smp_mb__after_clear_bit();
1408 if (queue_delayed_work(glock_workqueue, &gl->gl_work, 0) == 0)
1409 gfs2_glock_put_nolock(gl);
1410 spin_unlock(&gl->gl_spin);
1411 spin_lock(&lru_lock);
1412 continue;
1413 }
1414 nr_skipped++;
1415 list_add(&gl->gl_lru, &skipped);
1416 set_bit(GLF_LRU, &gl->gl_flags);
1417 }
1418 list_splice(&skipped, &lru_list);
1419 atomic_add(nr_skipped, &lru_count);
1420 spin_unlock(&lru_lock);
1421out:
1422 return (atomic_read(&lru_count) / 100) * sysctl_vfs_cache_pressure;
1423}
1424
1425static struct shrinker glock_shrinker = {
1426 .shrink = gfs2_shrink_glock_memory,
1427 .seeks = DEFAULT_SEEKS,
1428};
1429
1430/**
1431 * examine_bucket - Call a function for glock in a hash bucket
1432 * @examiner: the function
1433 * @sdp: the filesystem
1434 * @bucket: the bucket
1435 *
1436 */
1437
1438static void examine_bucket(glock_examiner examiner, const struct gfs2_sbd *sdp,
1439 unsigned int hash)
1440{
1441 struct gfs2_glock *gl;
1442 struct hlist_bl_head *head = &gl_hash_table[hash];
1443 struct hlist_bl_node *pos;
1444
1445 rcu_read_lock();
1446 hlist_bl_for_each_entry_rcu(gl, pos, head, gl_list) {
1447 if ((gl->gl_sbd == sdp) && atomic_read(&gl->gl_ref))
1448 examiner(gl);
1449 }
1450 rcu_read_unlock();
1451 cond_resched();
1452}
1453
1454static void glock_hash_walk(glock_examiner examiner, const struct gfs2_sbd *sdp)
1455{
1456 unsigned x;
1457
1458 for (x = 0; x < GFS2_GL_HASH_SIZE; x++)
1459 examine_bucket(examiner, sdp, x);
1460}
1461
1462
1463/**
1464 * thaw_glock - thaw out a glock which has an unprocessed reply waiting
1465 * @gl: The glock to thaw
1466 *
1467 * N.B. When we freeze a glock, we leave a ref to the glock outstanding,
1468 * so this has to result in the ref count being dropped by one.
1469 */
1470
1471static void thaw_glock(struct gfs2_glock *gl)
1472{
1473 if (!test_and_clear_bit(GLF_FROZEN, &gl->gl_flags))
1474 return;
1475 set_bit(GLF_REPLY_PENDING, &gl->gl_flags);
1476 gfs2_glock_hold(gl);
1477 if (queue_delayed_work(glock_workqueue, &gl->gl_work, 0) == 0)
1478 gfs2_glock_put(gl);
1479}
1480
1481/**
1482 * clear_glock - look at a glock and see if we can free it from glock cache
1483 * @gl: the glock to look at
1484 *
1485 */
1486
1487static void clear_glock(struct gfs2_glock *gl)
1488{
1489 gfs2_glock_remove_from_lru(gl);
1490
1491 spin_lock(&gl->gl_spin);
1492 if (gl->gl_state != LM_ST_UNLOCKED)
1493 handle_callback(gl, LM_ST_UNLOCKED, 0);
1494 spin_unlock(&gl->gl_spin);
1495 gfs2_glock_hold(gl);
1496 if (queue_delayed_work(glock_workqueue, &gl->gl_work, 0) == 0)
1497 gfs2_glock_put(gl);
1498}
1499
1500/**
1501 * gfs2_glock_thaw - Thaw any frozen glocks
1502 * @sdp: The super block
1503 *
1504 */
1505
1506void gfs2_glock_thaw(struct gfs2_sbd *sdp)
1507{
1508 glock_hash_walk(thaw_glock, sdp);
1509}
1510
1511static int dump_glock(struct seq_file *seq, struct gfs2_glock *gl)
1512{
1513 int ret;
1514 spin_lock(&gl->gl_spin);
1515 ret = __dump_glock(seq, gl);
1516 spin_unlock(&gl->gl_spin);
1517 return ret;
1518}
1519
1520static void dump_glock_func(struct gfs2_glock *gl)
1521{
1522 dump_glock(NULL, gl);
1523}
1524
1525/**
1526 * gfs2_gl_hash_clear - Empty out the glock hash table
1527 * @sdp: the filesystem
1528 * @wait: wait until it's all gone
1529 *
1530 * Called when unmounting the filesystem.
1531 */
1532
1533void gfs2_gl_hash_clear(struct gfs2_sbd *sdp)
1534{
1535 glock_hash_walk(clear_glock, sdp);
1536 flush_workqueue(glock_workqueue);
1537 wait_event(sdp->sd_glock_wait, atomic_read(&sdp->sd_glock_disposal) == 0);
1538 glock_hash_walk(dump_glock_func, sdp);
1539}
1540
1541void gfs2_glock_finish_truncate(struct gfs2_inode *ip)
1542{
1543 struct gfs2_glock *gl = ip->i_gl;
1544 int ret;
1545
1546 ret = gfs2_truncatei_resume(ip);
1547 gfs2_assert_withdraw(gl->gl_sbd, ret == 0);
1548
1549 spin_lock(&gl->gl_spin);
1550 clear_bit(GLF_LOCK, &gl->gl_flags);
1551 run_queue(gl, 1);
1552 spin_unlock(&gl->gl_spin);
1553}
1554
1555static const char *state2str(unsigned state)
1556{
1557 switch(state) {
1558 case LM_ST_UNLOCKED:
1559 return "UN";
1560 case LM_ST_SHARED:
1561 return "SH";
1562 case LM_ST_DEFERRED:
1563 return "DF";
1564 case LM_ST_EXCLUSIVE:
1565 return "EX";
1566 }
1567 return "??";
1568}
1569
1570static const char *hflags2str(char *buf, unsigned flags, unsigned long iflags)
1571{
1572 char *p = buf;
1573 if (flags & LM_FLAG_TRY)
1574 *p++ = 't';
1575 if (flags & LM_FLAG_TRY_1CB)
1576 *p++ = 'T';
1577 if (flags & LM_FLAG_NOEXP)
1578 *p++ = 'e';
1579 if (flags & LM_FLAG_ANY)
1580 *p++ = 'A';
1581 if (flags & LM_FLAG_PRIORITY)
1582 *p++ = 'p';
1583 if (flags & GL_ASYNC)
1584 *p++ = 'a';
1585 if (flags & GL_EXACT)
1586 *p++ = 'E';
1587 if (flags & GL_NOCACHE)
1588 *p++ = 'c';
1589 if (test_bit(HIF_HOLDER, &iflags))
1590 *p++ = 'H';
1591 if (test_bit(HIF_WAIT, &iflags))
1592 *p++ = 'W';
1593 if (test_bit(HIF_FIRST, &iflags))
1594 *p++ = 'F';
1595 *p = 0;
1596 return buf;
1597}
1598
1599/**
1600 * dump_holder - print information about a glock holder
1601 * @seq: the seq_file struct
1602 * @gh: the glock holder
1603 *
1604 * Returns: 0 on success, -ENOBUFS when we run out of space
1605 */
1606
1607static int dump_holder(struct seq_file *seq, const struct gfs2_holder *gh)
1608{
1609 struct task_struct *gh_owner = NULL;
1610 char flags_buf[32];
1611
1612 if (gh->gh_owner_pid)
1613 gh_owner = pid_task(gh->gh_owner_pid, PIDTYPE_PID);
1614 gfs2_print_dbg(seq, " H: s:%s f:%s e:%d p:%ld [%s] %pS\n",
1615 state2str(gh->gh_state),
1616 hflags2str(flags_buf, gh->gh_flags, gh->gh_iflags),
1617 gh->gh_error,
1618 gh->gh_owner_pid ? (long)pid_nr(gh->gh_owner_pid) : -1,
1619 gh_owner ? gh_owner->comm : "(ended)",
1620 (void *)gh->gh_ip);
1621 return 0;
1622}
1623
1624static const char *gflags2str(char *buf, const struct gfs2_glock *gl)
1625{
1626 const unsigned long *gflags = &gl->gl_flags;
1627 char *p = buf;
1628
1629 if (test_bit(GLF_LOCK, gflags))
1630 *p++ = 'l';
1631 if (test_bit(GLF_DEMOTE, gflags))
1632 *p++ = 'D';
1633 if (test_bit(GLF_PENDING_DEMOTE, gflags))
1634 *p++ = 'd';
1635 if (test_bit(GLF_DEMOTE_IN_PROGRESS, gflags))
1636 *p++ = 'p';
1637 if (test_bit(GLF_DIRTY, gflags))
1638 *p++ = 'y';
1639 if (test_bit(GLF_LFLUSH, gflags))
1640 *p++ = 'f';
1641 if (test_bit(GLF_INVALIDATE_IN_PROGRESS, gflags))
1642 *p++ = 'i';
1643 if (test_bit(GLF_REPLY_PENDING, gflags))
1644 *p++ = 'r';
1645 if (test_bit(GLF_INITIAL, gflags))
1646 *p++ = 'I';
1647 if (test_bit(GLF_FROZEN, gflags))
1648 *p++ = 'F';
1649 if (test_bit(GLF_QUEUED, gflags))
1650 *p++ = 'q';
1651 if (test_bit(GLF_LRU, gflags))
1652 *p++ = 'L';
1653 if (gl->gl_object)
1654 *p++ = 'o';
1655 *p = 0;
1656 return buf;
1657}
1658
1659/**
1660 * __dump_glock - print information about a glock
1661 * @seq: The seq_file struct
1662 * @gl: the glock
1663 *
1664 * The file format is as follows:
1665 * One line per object, capital letters are used to indicate objects
1666 * G = glock, I = Inode, R = rgrp, H = holder. Glocks are not indented,
1667 * other objects are indented by a single space and follow the glock to
1668 * which they are related. Fields are indicated by lower case letters
1669 * followed by a colon and the field value, except for strings which are in
1670 * [] so that its possible to see if they are composed of spaces for
1671 * example. The field's are n = number (id of the object), f = flags,
1672 * t = type, s = state, r = refcount, e = error, p = pid.
1673 *
1674 * Returns: 0 on success, -ENOBUFS when we run out of space
1675 */
1676
1677static int __dump_glock(struct seq_file *seq, const struct gfs2_glock *gl)
1678{
1679 const struct gfs2_glock_operations *glops = gl->gl_ops;
1680 unsigned long long dtime;
1681 const struct gfs2_holder *gh;
1682 char gflags_buf[32];
1683 int error = 0;
1684
1685 dtime = jiffies - gl->gl_demote_time;
1686 dtime *= 1000000/HZ; /* demote time in uSec */
1687 if (!test_bit(GLF_DEMOTE, &gl->gl_flags))
1688 dtime = 0;
1689 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",
1690 state2str(gl->gl_state),
1691 gl->gl_name.ln_type,
1692 (unsigned long long)gl->gl_name.ln_number,
1693 gflags2str(gflags_buf, gl),
1694 state2str(gl->gl_target),
1695 state2str(gl->gl_demote_state), dtime,
1696 atomic_read(&gl->gl_ail_count),
1697 atomic_read(&gl->gl_revokes),
1698 atomic_read(&gl->gl_ref), gl->gl_hold_time);
1699
1700 list_for_each_entry(gh, &gl->gl_holders, gh_list) {
1701 error = dump_holder(seq, gh);
1702 if (error)
1703 goto out;
1704 }
1705 if (gl->gl_state != LM_ST_UNLOCKED && glops->go_dump)
1706 error = glops->go_dump(seq, gl);
1707out:
1708 return error;
1709}
1710
1711
1712
1713
1714int __init gfs2_glock_init(void)
1715{
1716 unsigned i;
1717 for(i = 0; i < GFS2_GL_HASH_SIZE; i++) {
1718 INIT_HLIST_BL_HEAD(&gl_hash_table[i]);
1719 }
1720
1721 glock_workqueue = alloc_workqueue("glock_workqueue", WQ_MEM_RECLAIM |
1722 WQ_HIGHPRI | WQ_FREEZABLE, 0);
1723 if (IS_ERR(glock_workqueue))
1724 return PTR_ERR(glock_workqueue);
1725 gfs2_delete_workqueue = alloc_workqueue("delete_workqueue",
1726 WQ_MEM_RECLAIM | WQ_FREEZABLE,
1727 0);
1728 if (IS_ERR(gfs2_delete_workqueue)) {
1729 destroy_workqueue(glock_workqueue);
1730 return PTR_ERR(gfs2_delete_workqueue);
1731 }
1732
1733 register_shrinker(&glock_shrinker);
1734
1735 return 0;
1736}
1737
1738void gfs2_glock_exit(void)
1739{
1740 unregister_shrinker(&glock_shrinker);
1741 destroy_workqueue(glock_workqueue);
1742 destroy_workqueue(gfs2_delete_workqueue);
1743}
1744
1745static inline struct gfs2_glock *glock_hash_chain(unsigned hash)
1746{
1747 return hlist_bl_entry(hlist_bl_first_rcu(&gl_hash_table[hash]),
1748 struct gfs2_glock, gl_list);
1749}
1750
1751static inline struct gfs2_glock *glock_hash_next(struct gfs2_glock *gl)
1752{
1753 return hlist_bl_entry(rcu_dereference(gl->gl_list.next),
1754 struct gfs2_glock, gl_list);
1755}
1756
1757static int gfs2_glock_iter_next(struct gfs2_glock_iter *gi)
1758{
1759 struct gfs2_glock *gl;
1760
1761 do {
1762 gl = gi->gl;
1763 if (gl) {
1764 gi->gl = glock_hash_next(gl);
1765 } else {
1766 gi->gl = glock_hash_chain(gi->hash);
1767 }
1768 while (gi->gl == NULL) {
1769 gi->hash++;
1770 if (gi->hash >= GFS2_GL_HASH_SIZE) {
1771 rcu_read_unlock();
1772 return 1;
1773 }
1774 gi->gl = glock_hash_chain(gi->hash);
1775 }
1776 /* Skip entries for other sb and dead entries */
1777 } while (gi->sdp != gi->gl->gl_sbd || atomic_read(&gi->gl->gl_ref) == 0);
1778
1779 return 0;
1780}
1781
1782static void *gfs2_glock_seq_start(struct seq_file *seq, loff_t *pos)
1783{
1784 struct gfs2_glock_iter *gi = seq->private;
1785 loff_t n = *pos;
1786
1787 gi->hash = 0;
1788 rcu_read_lock();
1789
1790 do {
1791 if (gfs2_glock_iter_next(gi))
1792 return NULL;
1793 } while (n--);
1794
1795 return gi->gl;
1796}
1797
1798static void *gfs2_glock_seq_next(struct seq_file *seq, void *iter_ptr,
1799 loff_t *pos)
1800{
1801 struct gfs2_glock_iter *gi = seq->private;
1802
1803 (*pos)++;
1804
1805 if (gfs2_glock_iter_next(gi))
1806 return NULL;
1807
1808 return gi->gl;
1809}
1810
1811static void gfs2_glock_seq_stop(struct seq_file *seq, void *iter_ptr)
1812{
1813 struct gfs2_glock_iter *gi = seq->private;
1814
1815 if (gi->gl)
1816 rcu_read_unlock();
1817 gi->gl = NULL;
1818}
1819
1820static int gfs2_glock_seq_show(struct seq_file *seq, void *iter_ptr)
1821{
1822 return dump_glock(seq, iter_ptr);
1823}
1824
1825static const struct seq_operations gfs2_glock_seq_ops = {
1826 .start = gfs2_glock_seq_start,
1827 .next = gfs2_glock_seq_next,
1828 .stop = gfs2_glock_seq_stop,
1829 .show = gfs2_glock_seq_show,
1830};
1831
1832static int gfs2_debugfs_open(struct inode *inode, struct file *file)
1833{
1834 int ret = seq_open_private(file, &gfs2_glock_seq_ops,
1835 sizeof(struct gfs2_glock_iter));
1836 if (ret == 0) {
1837 struct seq_file *seq = file->private_data;
1838 struct gfs2_glock_iter *gi = seq->private;
1839 gi->sdp = inode->i_private;
1840 }
1841 return ret;
1842}
1843
1844static const struct file_operations gfs2_debug_fops = {
1845 .owner = THIS_MODULE,
1846 .open = gfs2_debugfs_open,
1847 .read = seq_read,
1848 .llseek = seq_lseek,
1849 .release = seq_release_private,
1850};
1851
1852int gfs2_create_debugfs_file(struct gfs2_sbd *sdp)
1853{
1854 sdp->debugfs_dir = debugfs_create_dir(sdp->sd_table_name, gfs2_root);
1855 if (!sdp->debugfs_dir)
1856 return -ENOMEM;
1857 sdp->debugfs_dentry_glocks = debugfs_create_file("glocks",
1858 S_IFREG | S_IRUGO,
1859 sdp->debugfs_dir, sdp,
1860 &gfs2_debug_fops);
1861 if (!sdp->debugfs_dentry_glocks)
1862 return -ENOMEM;
1863
1864 return 0;
1865}
1866
1867void gfs2_delete_debugfs_file(struct gfs2_sbd *sdp)
1868{
1869 if (sdp && sdp->debugfs_dir) {
1870 if (sdp->debugfs_dentry_glocks) {
1871 debugfs_remove(sdp->debugfs_dentry_glocks);
1872 sdp->debugfs_dentry_glocks = NULL;
1873 }
1874 debugfs_remove(sdp->debugfs_dir);
1875 sdp->debugfs_dir = NULL;
1876 }
1877}
1878
1879int gfs2_register_debugfs(void)
1880{
1881 gfs2_root = debugfs_create_dir("gfs2", NULL);
1882 return gfs2_root ? 0 : -ENOMEM;
1883}
1884
1885void gfs2_unregister_debugfs(void)
1886{
1887 debugfs_remove(gfs2_root);
1888 gfs2_root = NULL;
1889}
1// SPDX-License-Identifier: GPL-2.0-only
2/*
3 * Copyright (C) Sistina Software, Inc. 1997-2003 All rights reserved.
4 * Copyright (C) 2004-2008 Red Hat, Inc. All rights reserved.
5 */
6
7#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
8
9#include <linux/sched.h>
10#include <linux/slab.h>
11#include <linux/spinlock.h>
12#include <linux/buffer_head.h>
13#include <linux/delay.h>
14#include <linux/sort.h>
15#include <linux/hash.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 <linux/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#include <linux/list_sort.h>
34#include <linux/lockref.h>
35#include <linux/rhashtable.h>
36#include <linux/pid_namespace.h>
37#include <linux/fdtable.h>
38#include <linux/file.h>
39
40#include "gfs2.h"
41#include "incore.h"
42#include "glock.h"
43#include "glops.h"
44#include "inode.h"
45#include "lops.h"
46#include "meta_io.h"
47#include "quota.h"
48#include "super.h"
49#include "util.h"
50#include "bmap.h"
51#define CREATE_TRACE_POINTS
52#include "trace_gfs2.h"
53
54struct gfs2_glock_iter {
55 struct gfs2_sbd *sdp; /* incore superblock */
56 struct rhashtable_iter hti; /* rhashtable iterator */
57 struct gfs2_glock *gl; /* current glock struct */
58 loff_t last_pos; /* last position */
59};
60
61typedef void (*glock_examiner) (struct gfs2_glock * gl);
62
63static void do_xmote(struct gfs2_glock *gl, struct gfs2_holder *gh, unsigned int target);
64static void __gfs2_glock_dq(struct gfs2_holder *gh);
65static void handle_callback(struct gfs2_glock *gl, unsigned int state,
66 unsigned long delay, bool remote);
67
68static struct dentry *gfs2_root;
69static struct workqueue_struct *glock_workqueue;
70static LIST_HEAD(lru_list);
71static atomic_t lru_count = ATOMIC_INIT(0);
72static DEFINE_SPINLOCK(lru_lock);
73
74#define GFS2_GL_HASH_SHIFT 15
75#define GFS2_GL_HASH_SIZE BIT(GFS2_GL_HASH_SHIFT)
76
77static const struct rhashtable_params ht_parms = {
78 .nelem_hint = GFS2_GL_HASH_SIZE * 3 / 4,
79 .key_len = offsetofend(struct lm_lockname, ln_type),
80 .key_offset = offsetof(struct gfs2_glock, gl_name),
81 .head_offset = offsetof(struct gfs2_glock, gl_node),
82};
83
84static struct rhashtable gl_hash_table;
85
86#define GLOCK_WAIT_TABLE_BITS 12
87#define GLOCK_WAIT_TABLE_SIZE (1 << GLOCK_WAIT_TABLE_BITS)
88static wait_queue_head_t glock_wait_table[GLOCK_WAIT_TABLE_SIZE] __cacheline_aligned;
89
90struct wait_glock_queue {
91 struct lm_lockname *name;
92 wait_queue_entry_t wait;
93};
94
95static int glock_wake_function(wait_queue_entry_t *wait, unsigned int mode,
96 int sync, void *key)
97{
98 struct wait_glock_queue *wait_glock =
99 container_of(wait, struct wait_glock_queue, wait);
100 struct lm_lockname *wait_name = wait_glock->name;
101 struct lm_lockname *wake_name = key;
102
103 if (wake_name->ln_sbd != wait_name->ln_sbd ||
104 wake_name->ln_number != wait_name->ln_number ||
105 wake_name->ln_type != wait_name->ln_type)
106 return 0;
107 return autoremove_wake_function(wait, mode, sync, key);
108}
109
110static wait_queue_head_t *glock_waitqueue(struct lm_lockname *name)
111{
112 u32 hash = jhash2((u32 *)name, ht_parms.key_len / 4, 0);
113
114 return glock_wait_table + hash_32(hash, GLOCK_WAIT_TABLE_BITS);
115}
116
117/**
118 * wake_up_glock - Wake up waiters on a glock
119 * @gl: the glock
120 */
121static void wake_up_glock(struct gfs2_glock *gl)
122{
123 wait_queue_head_t *wq = glock_waitqueue(&gl->gl_name);
124
125 if (waitqueue_active(wq))
126 __wake_up(wq, TASK_NORMAL, 1, &gl->gl_name);
127}
128
129static void gfs2_glock_dealloc(struct rcu_head *rcu)
130{
131 struct gfs2_glock *gl = container_of(rcu, struct gfs2_glock, gl_rcu);
132
133 kfree(gl->gl_lksb.sb_lvbptr);
134 if (gl->gl_ops->go_flags & GLOF_ASPACE) {
135 struct gfs2_glock_aspace *gla =
136 container_of(gl, struct gfs2_glock_aspace, glock);
137 kmem_cache_free(gfs2_glock_aspace_cachep, gla);
138 } else
139 kmem_cache_free(gfs2_glock_cachep, gl);
140}
141
142/**
143 * glock_blocked_by_withdraw - determine if we can still use a glock
144 * @gl: the glock
145 *
146 * We need to allow some glocks to be enqueued, dequeued, promoted, and demoted
147 * when we're withdrawn. For example, to maintain metadata integrity, we should
148 * disallow the use of inode and rgrp glocks when withdrawn. Other glocks like
149 * the iopen or freeze glock may be safely used because none of their
150 * metadata goes through the journal. So in general, we should disallow all
151 * glocks that are journaled, and allow all the others. One exception is:
152 * we need to allow our active journal to be promoted and demoted so others
153 * may recover it and we can reacquire it when they're done.
154 */
155static bool glock_blocked_by_withdraw(struct gfs2_glock *gl)
156{
157 struct gfs2_sbd *sdp = gl->gl_name.ln_sbd;
158
159 if (!gfs2_withdrawing_or_withdrawn(sdp))
160 return false;
161 if (gl->gl_ops->go_flags & GLOF_NONDISK)
162 return false;
163 if (!sdp->sd_jdesc ||
164 gl->gl_name.ln_number == sdp->sd_jdesc->jd_no_addr)
165 return false;
166 return true;
167}
168
169void gfs2_glock_free(struct gfs2_glock *gl)
170{
171 struct gfs2_sbd *sdp = gl->gl_name.ln_sbd;
172
173 gfs2_glock_assert_withdraw(gl, atomic_read(&gl->gl_revokes) == 0);
174 rhashtable_remove_fast(&gl_hash_table, &gl->gl_node, ht_parms);
175 smp_mb();
176 wake_up_glock(gl);
177 call_rcu(&gl->gl_rcu, gfs2_glock_dealloc);
178 if (atomic_dec_and_test(&sdp->sd_glock_disposal))
179 wake_up(&sdp->sd_kill_wait);
180}
181
182/**
183 * gfs2_glock_hold() - increment reference count on glock
184 * @gl: The glock to hold
185 *
186 */
187
188struct gfs2_glock *gfs2_glock_hold(struct gfs2_glock *gl)
189{
190 GLOCK_BUG_ON(gl, __lockref_is_dead(&gl->gl_lockref));
191 lockref_get(&gl->gl_lockref);
192 return gl;
193}
194
195/**
196 * demote_ok - Check to see if it's ok to unlock a glock
197 * @gl: the glock
198 *
199 * Returns: 1 if it's ok
200 */
201
202static int demote_ok(const struct gfs2_glock *gl)
203{
204 const struct gfs2_glock_operations *glops = gl->gl_ops;
205
206 if (gl->gl_state == LM_ST_UNLOCKED)
207 return 0;
208 if (!list_empty(&gl->gl_holders))
209 return 0;
210 if (glops->go_demote_ok)
211 return glops->go_demote_ok(gl);
212 return 1;
213}
214
215
216void gfs2_glock_add_to_lru(struct gfs2_glock *gl)
217{
218 if (!(gl->gl_ops->go_flags & GLOF_LRU))
219 return;
220
221 spin_lock(&lru_lock);
222
223 list_move_tail(&gl->gl_lru, &lru_list);
224
225 if (!test_bit(GLF_LRU, &gl->gl_flags)) {
226 set_bit(GLF_LRU, &gl->gl_flags);
227 atomic_inc(&lru_count);
228 }
229
230 spin_unlock(&lru_lock);
231}
232
233static void gfs2_glock_remove_from_lru(struct gfs2_glock *gl)
234{
235 if (!(gl->gl_ops->go_flags & GLOF_LRU))
236 return;
237
238 spin_lock(&lru_lock);
239 if (test_bit(GLF_LRU, &gl->gl_flags)) {
240 list_del_init(&gl->gl_lru);
241 atomic_dec(&lru_count);
242 clear_bit(GLF_LRU, &gl->gl_flags);
243 }
244 spin_unlock(&lru_lock);
245}
246
247/*
248 * Enqueue the glock on the work queue. Passes one glock reference on to the
249 * work queue.
250 */
251static void __gfs2_glock_queue_work(struct gfs2_glock *gl, unsigned long delay) {
252 if (!queue_delayed_work(glock_workqueue, &gl->gl_work, delay)) {
253 /*
254 * We are holding the lockref spinlock, and the work was still
255 * queued above. The queued work (glock_work_func) takes that
256 * spinlock before dropping its glock reference(s), so it
257 * cannot have dropped them in the meantime.
258 */
259 GLOCK_BUG_ON(gl, gl->gl_lockref.count < 2);
260 gl->gl_lockref.count--;
261 }
262}
263
264static void gfs2_glock_queue_work(struct gfs2_glock *gl, unsigned long delay) {
265 spin_lock(&gl->gl_lockref.lock);
266 __gfs2_glock_queue_work(gl, delay);
267 spin_unlock(&gl->gl_lockref.lock);
268}
269
270static void __gfs2_glock_put(struct gfs2_glock *gl)
271{
272 struct gfs2_sbd *sdp = gl->gl_name.ln_sbd;
273 struct address_space *mapping = gfs2_glock2aspace(gl);
274
275 lockref_mark_dead(&gl->gl_lockref);
276 spin_unlock(&gl->gl_lockref.lock);
277 gfs2_glock_remove_from_lru(gl);
278 GLOCK_BUG_ON(gl, !list_empty(&gl->gl_holders));
279 if (mapping) {
280 truncate_inode_pages_final(mapping);
281 if (!gfs2_withdrawing_or_withdrawn(sdp))
282 GLOCK_BUG_ON(gl, !mapping_empty(mapping));
283 }
284 trace_gfs2_glock_put(gl);
285 sdp->sd_lockstruct.ls_ops->lm_put_lock(gl);
286}
287
288/*
289 * Cause the glock to be put in work queue context.
290 */
291void gfs2_glock_queue_put(struct gfs2_glock *gl)
292{
293 gfs2_glock_queue_work(gl, 0);
294}
295
296/**
297 * gfs2_glock_put() - Decrement reference count on glock
298 * @gl: The glock to put
299 *
300 */
301
302void gfs2_glock_put(struct gfs2_glock *gl)
303{
304 if (lockref_put_or_lock(&gl->gl_lockref))
305 return;
306
307 __gfs2_glock_put(gl);
308}
309
310/**
311 * may_grant - check if it's ok to grant a new lock
312 * @gl: The glock
313 * @current_gh: One of the current holders of @gl
314 * @gh: The lock request which we wish to grant
315 *
316 * With our current compatibility rules, if a glock has one or more active
317 * holders (HIF_HOLDER flag set), any of those holders can be passed in as
318 * @current_gh; they are all the same as far as compatibility with the new @gh
319 * goes.
320 *
321 * Returns true if it's ok to grant the lock.
322 */
323
324static inline bool may_grant(struct gfs2_glock *gl,
325 struct gfs2_holder *current_gh,
326 struct gfs2_holder *gh)
327{
328 if (current_gh) {
329 GLOCK_BUG_ON(gl, !test_bit(HIF_HOLDER, ¤t_gh->gh_iflags));
330
331 switch(current_gh->gh_state) {
332 case LM_ST_EXCLUSIVE:
333 /*
334 * Here we make a special exception to grant holders
335 * who agree to share the EX lock with other holders
336 * who also have the bit set. If the original holder
337 * has the LM_FLAG_NODE_SCOPE bit set, we grant more
338 * holders with the bit set.
339 */
340 return gh->gh_state == LM_ST_EXCLUSIVE &&
341 (current_gh->gh_flags & LM_FLAG_NODE_SCOPE) &&
342 (gh->gh_flags & LM_FLAG_NODE_SCOPE);
343
344 case LM_ST_SHARED:
345 case LM_ST_DEFERRED:
346 return gh->gh_state == current_gh->gh_state;
347
348 default:
349 return false;
350 }
351 }
352
353 if (gl->gl_state == gh->gh_state)
354 return true;
355 if (gh->gh_flags & GL_EXACT)
356 return false;
357 if (gl->gl_state == LM_ST_EXCLUSIVE) {
358 return gh->gh_state == LM_ST_SHARED ||
359 gh->gh_state == LM_ST_DEFERRED;
360 }
361 if (gh->gh_flags & LM_FLAG_ANY)
362 return gl->gl_state != LM_ST_UNLOCKED;
363 return false;
364}
365
366static void gfs2_holder_wake(struct gfs2_holder *gh)
367{
368 clear_bit(HIF_WAIT, &gh->gh_iflags);
369 smp_mb__after_atomic();
370 wake_up_bit(&gh->gh_iflags, HIF_WAIT);
371 if (gh->gh_flags & GL_ASYNC) {
372 struct gfs2_sbd *sdp = gh->gh_gl->gl_name.ln_sbd;
373
374 wake_up(&sdp->sd_async_glock_wait);
375 }
376}
377
378/**
379 * do_error - Something unexpected has happened during a lock request
380 * @gl: The glock
381 * @ret: The status from the DLM
382 */
383
384static void do_error(struct gfs2_glock *gl, const int ret)
385{
386 struct gfs2_holder *gh, *tmp;
387
388 list_for_each_entry_safe(gh, tmp, &gl->gl_holders, gh_list) {
389 if (test_bit(HIF_HOLDER, &gh->gh_iflags))
390 continue;
391 if (ret & LM_OUT_ERROR)
392 gh->gh_error = -EIO;
393 else if (gh->gh_flags & (LM_FLAG_TRY | LM_FLAG_TRY_1CB))
394 gh->gh_error = GLR_TRYFAILED;
395 else
396 continue;
397 list_del_init(&gh->gh_list);
398 trace_gfs2_glock_queue(gh, 0);
399 gfs2_holder_wake(gh);
400 }
401}
402
403/**
404 * find_first_holder - find the first "holder" gh
405 * @gl: the glock
406 */
407
408static inline struct gfs2_holder *find_first_holder(const struct gfs2_glock *gl)
409{
410 struct gfs2_holder *gh;
411
412 if (!list_empty(&gl->gl_holders)) {
413 gh = list_first_entry(&gl->gl_holders, struct gfs2_holder,
414 gh_list);
415 if (test_bit(HIF_HOLDER, &gh->gh_iflags))
416 return gh;
417 }
418 return NULL;
419}
420
421/*
422 * gfs2_instantiate - Call the glops instantiate function
423 * @gh: The glock holder
424 *
425 * Returns: 0 if instantiate was successful, or error.
426 */
427int gfs2_instantiate(struct gfs2_holder *gh)
428{
429 struct gfs2_glock *gl = gh->gh_gl;
430 const struct gfs2_glock_operations *glops = gl->gl_ops;
431 int ret;
432
433again:
434 if (!test_bit(GLF_INSTANTIATE_NEEDED, &gl->gl_flags))
435 goto done;
436
437 /*
438 * Since we unlock the lockref lock, we set a flag to indicate
439 * instantiate is in progress.
440 */
441 if (test_and_set_bit(GLF_INSTANTIATE_IN_PROG, &gl->gl_flags)) {
442 wait_on_bit(&gl->gl_flags, GLF_INSTANTIATE_IN_PROG,
443 TASK_UNINTERRUPTIBLE);
444 /*
445 * Here we just waited for a different instantiate to finish.
446 * But that may not have been successful, as when a process
447 * locks an inode glock _before_ it has an actual inode to
448 * instantiate into. So we check again. This process might
449 * have an inode to instantiate, so might be successful.
450 */
451 goto again;
452 }
453
454 ret = glops->go_instantiate(gl);
455 if (!ret)
456 clear_bit(GLF_INSTANTIATE_NEEDED, &gl->gl_flags);
457 clear_and_wake_up_bit(GLF_INSTANTIATE_IN_PROG, &gl->gl_flags);
458 if (ret)
459 return ret;
460
461done:
462 if (glops->go_held)
463 return glops->go_held(gh);
464 return 0;
465}
466
467/**
468 * do_promote - promote as many requests as possible on the current queue
469 * @gl: The glock
470 *
471 * Returns true on success (i.e., progress was made or there are no waiters).
472 */
473
474static bool do_promote(struct gfs2_glock *gl)
475{
476 struct gfs2_holder *gh, *current_gh;
477
478 current_gh = find_first_holder(gl);
479 list_for_each_entry(gh, &gl->gl_holders, gh_list) {
480 if (test_bit(HIF_HOLDER, &gh->gh_iflags))
481 continue;
482 if (!may_grant(gl, current_gh, gh)) {
483 /*
484 * If we get here, it means we may not grant this
485 * holder for some reason. If this holder is at the
486 * head of the list, it means we have a blocked holder
487 * at the head, so return false.
488 */
489 if (list_is_first(&gh->gh_list, &gl->gl_holders))
490 return false;
491 do_error(gl, 0);
492 break;
493 }
494 set_bit(HIF_HOLDER, &gh->gh_iflags);
495 trace_gfs2_promote(gh);
496 gfs2_holder_wake(gh);
497 if (!current_gh)
498 current_gh = gh;
499 }
500 return true;
501}
502
503/**
504 * find_first_waiter - find the first gh that's waiting for the glock
505 * @gl: the glock
506 */
507
508static inline struct gfs2_holder *find_first_waiter(const struct gfs2_glock *gl)
509{
510 struct gfs2_holder *gh;
511
512 list_for_each_entry(gh, &gl->gl_holders, gh_list) {
513 if (!test_bit(HIF_HOLDER, &gh->gh_iflags))
514 return gh;
515 }
516 return NULL;
517}
518
519/**
520 * find_last_waiter - find the last gh that's waiting for the glock
521 * @gl: the glock
522 *
523 * This also is a fast way of finding out if there are any waiters.
524 */
525
526static inline struct gfs2_holder *find_last_waiter(const struct gfs2_glock *gl)
527{
528 struct gfs2_holder *gh;
529
530 if (list_empty(&gl->gl_holders))
531 return NULL;
532 gh = list_last_entry(&gl->gl_holders, struct gfs2_holder, gh_list);
533 return test_bit(HIF_HOLDER, &gh->gh_iflags) ? NULL : gh;
534}
535
536/**
537 * state_change - record that the glock is now in a different state
538 * @gl: the glock
539 * @new_state: the new state
540 */
541
542static void state_change(struct gfs2_glock *gl, unsigned int new_state)
543{
544 int held1, held2;
545
546 held1 = (gl->gl_state != LM_ST_UNLOCKED);
547 held2 = (new_state != LM_ST_UNLOCKED);
548
549 if (held1 != held2) {
550 GLOCK_BUG_ON(gl, __lockref_is_dead(&gl->gl_lockref));
551 if (held2)
552 gl->gl_lockref.count++;
553 else
554 gl->gl_lockref.count--;
555 }
556 if (new_state != gl->gl_target)
557 /* shorten our minimum hold time */
558 gl->gl_hold_time = max(gl->gl_hold_time - GL_GLOCK_HOLD_DECR,
559 GL_GLOCK_MIN_HOLD);
560 gl->gl_state = new_state;
561 gl->gl_tchange = jiffies;
562}
563
564static void gfs2_set_demote(struct gfs2_glock *gl)
565{
566 struct gfs2_sbd *sdp = gl->gl_name.ln_sbd;
567
568 set_bit(GLF_DEMOTE, &gl->gl_flags);
569 smp_mb();
570 wake_up(&sdp->sd_async_glock_wait);
571}
572
573static void gfs2_demote_wake(struct gfs2_glock *gl)
574{
575 gl->gl_demote_state = LM_ST_EXCLUSIVE;
576 clear_bit(GLF_DEMOTE, &gl->gl_flags);
577 smp_mb__after_atomic();
578 wake_up_bit(&gl->gl_flags, GLF_DEMOTE);
579}
580
581/**
582 * finish_xmote - The DLM has replied to one of our lock requests
583 * @gl: The glock
584 * @ret: The status from the DLM
585 *
586 */
587
588static void finish_xmote(struct gfs2_glock *gl, unsigned int ret)
589{
590 const struct gfs2_glock_operations *glops = gl->gl_ops;
591 struct gfs2_holder *gh;
592 unsigned state = ret & LM_OUT_ST_MASK;
593
594 spin_lock(&gl->gl_lockref.lock);
595 trace_gfs2_glock_state_change(gl, state);
596 state_change(gl, state);
597 gh = find_first_waiter(gl);
598
599 /* Demote to UN request arrived during demote to SH or DF */
600 if (test_bit(GLF_DEMOTE_IN_PROGRESS, &gl->gl_flags) &&
601 state != LM_ST_UNLOCKED && gl->gl_demote_state == LM_ST_UNLOCKED)
602 gl->gl_target = LM_ST_UNLOCKED;
603
604 /* Check for state != intended state */
605 if (unlikely(state != gl->gl_target)) {
606 if (gh && (ret & LM_OUT_CANCELED))
607 gfs2_holder_wake(gh);
608 if (gh && !test_bit(GLF_DEMOTE_IN_PROGRESS, &gl->gl_flags)) {
609 /* move to back of queue and try next entry */
610 if (ret & LM_OUT_CANCELED) {
611 list_move_tail(&gh->gh_list, &gl->gl_holders);
612 gh = find_first_waiter(gl);
613 gl->gl_target = gh->gh_state;
614 if (do_promote(gl))
615 goto out;
616 goto retry;
617 }
618 /* Some error or failed "try lock" - report it */
619 if ((ret & LM_OUT_ERROR) ||
620 (gh->gh_flags & (LM_FLAG_TRY | LM_FLAG_TRY_1CB))) {
621 gl->gl_target = gl->gl_state;
622 do_error(gl, ret);
623 goto out;
624 }
625 }
626 switch(state) {
627 /* Unlocked due to conversion deadlock, try again */
628 case LM_ST_UNLOCKED:
629retry:
630 do_xmote(gl, gh, gl->gl_target);
631 break;
632 /* Conversion fails, unlock and try again */
633 case LM_ST_SHARED:
634 case LM_ST_DEFERRED:
635 do_xmote(gl, gh, LM_ST_UNLOCKED);
636 break;
637 default: /* Everything else */
638 fs_err(gl->gl_name.ln_sbd, "wanted %u got %u\n",
639 gl->gl_target, state);
640 GLOCK_BUG_ON(gl, 1);
641 }
642 spin_unlock(&gl->gl_lockref.lock);
643 return;
644 }
645
646 /* Fast path - we got what we asked for */
647 if (test_and_clear_bit(GLF_DEMOTE_IN_PROGRESS, &gl->gl_flags))
648 gfs2_demote_wake(gl);
649 if (state != LM_ST_UNLOCKED) {
650 if (glops->go_xmote_bh) {
651 int rv;
652
653 spin_unlock(&gl->gl_lockref.lock);
654 rv = glops->go_xmote_bh(gl);
655 spin_lock(&gl->gl_lockref.lock);
656 if (rv) {
657 do_error(gl, rv);
658 goto out;
659 }
660 }
661 do_promote(gl);
662 }
663out:
664 clear_bit(GLF_LOCK, &gl->gl_flags);
665 spin_unlock(&gl->gl_lockref.lock);
666}
667
668static bool is_system_glock(struct gfs2_glock *gl)
669{
670 struct gfs2_sbd *sdp = gl->gl_name.ln_sbd;
671 struct gfs2_inode *m_ip = GFS2_I(sdp->sd_statfs_inode);
672
673 if (gl == m_ip->i_gl)
674 return true;
675 return false;
676}
677
678/**
679 * do_xmote - Calls the DLM to change the state of a lock
680 * @gl: The lock state
681 * @gh: The holder (only for promotes)
682 * @target: The target lock state
683 *
684 */
685
686static void do_xmote(struct gfs2_glock *gl, struct gfs2_holder *gh,
687 unsigned int target)
688__releases(&gl->gl_lockref.lock)
689__acquires(&gl->gl_lockref.lock)
690{
691 const struct gfs2_glock_operations *glops = gl->gl_ops;
692 struct gfs2_sbd *sdp = gl->gl_name.ln_sbd;
693 unsigned int lck_flags = (unsigned int)(gh ? gh->gh_flags : 0);
694 int ret;
695
696 if (target != LM_ST_UNLOCKED && glock_blocked_by_withdraw(gl) &&
697 gh && !(gh->gh_flags & LM_FLAG_NOEXP))
698 goto skip_inval;
699
700 lck_flags &= (LM_FLAG_TRY | LM_FLAG_TRY_1CB | LM_FLAG_NOEXP);
701 GLOCK_BUG_ON(gl, gl->gl_state == target);
702 GLOCK_BUG_ON(gl, gl->gl_state == gl->gl_target);
703 if ((target == LM_ST_UNLOCKED || target == LM_ST_DEFERRED) &&
704 glops->go_inval) {
705 /*
706 * If another process is already doing the invalidate, let that
707 * finish first. The glock state machine will get back to this
708 * holder again later.
709 */
710 if (test_and_set_bit(GLF_INVALIDATE_IN_PROGRESS,
711 &gl->gl_flags))
712 return;
713 do_error(gl, 0); /* Fail queued try locks */
714 }
715 gl->gl_req = target;
716 set_bit(GLF_BLOCKING, &gl->gl_flags);
717 if ((gl->gl_req == LM_ST_UNLOCKED) ||
718 (gl->gl_state == LM_ST_EXCLUSIVE) ||
719 (lck_flags & (LM_FLAG_TRY|LM_FLAG_TRY_1CB)))
720 clear_bit(GLF_BLOCKING, &gl->gl_flags);
721 spin_unlock(&gl->gl_lockref.lock);
722 if (glops->go_sync) {
723 ret = glops->go_sync(gl);
724 /* If we had a problem syncing (due to io errors or whatever,
725 * we should not invalidate the metadata or tell dlm to
726 * release the glock to other nodes.
727 */
728 if (ret) {
729 if (cmpxchg(&sdp->sd_log_error, 0, ret)) {
730 fs_err(sdp, "Error %d syncing glock \n", ret);
731 gfs2_dump_glock(NULL, gl, true);
732 }
733 goto skip_inval;
734 }
735 }
736 if (test_bit(GLF_INVALIDATE_IN_PROGRESS, &gl->gl_flags)) {
737 /*
738 * The call to go_sync should have cleared out the ail list.
739 * If there are still items, we have a problem. We ought to
740 * withdraw, but we can't because the withdraw code also uses
741 * glocks. Warn about the error, dump the glock, then fall
742 * through and wait for logd to do the withdraw for us.
743 */
744 if ((atomic_read(&gl->gl_ail_count) != 0) &&
745 (!cmpxchg(&sdp->sd_log_error, 0, -EIO))) {
746 gfs2_glock_assert_warn(gl,
747 !atomic_read(&gl->gl_ail_count));
748 gfs2_dump_glock(NULL, gl, true);
749 }
750 glops->go_inval(gl, target == LM_ST_DEFERRED ? 0 : DIO_METADATA);
751 clear_bit(GLF_INVALIDATE_IN_PROGRESS, &gl->gl_flags);
752 }
753
754skip_inval:
755 gfs2_glock_hold(gl);
756 /*
757 * Check for an error encountered since we called go_sync and go_inval.
758 * If so, we can't withdraw from the glock code because the withdraw
759 * code itself uses glocks (see function signal_our_withdraw) to
760 * change the mount to read-only. Most importantly, we must not call
761 * dlm to unlock the glock until the journal is in a known good state
762 * (after journal replay) otherwise other nodes may use the object
763 * (rgrp or dinode) and then later, journal replay will corrupt the
764 * file system. The best we can do here is wait for the logd daemon
765 * to see sd_log_error and withdraw, and in the meantime, requeue the
766 * work for later.
767 *
768 * We make a special exception for some system glocks, such as the
769 * system statfs inode glock, which needs to be granted before the
770 * gfs2_quotad daemon can exit, and that exit needs to finish before
771 * we can unmount the withdrawn file system.
772 *
773 * However, if we're just unlocking the lock (say, for unmount, when
774 * gfs2_gl_hash_clear calls clear_glock) and recovery is complete
775 * then it's okay to tell dlm to unlock it.
776 */
777 if (unlikely(sdp->sd_log_error) && !gfs2_withdrawing_or_withdrawn(sdp))
778 gfs2_withdraw_delayed(sdp);
779 if (glock_blocked_by_withdraw(gl) &&
780 (target != LM_ST_UNLOCKED ||
781 test_bit(SDF_WITHDRAW_RECOVERY, &sdp->sd_flags))) {
782 if (!is_system_glock(gl)) {
783 handle_callback(gl, LM_ST_UNLOCKED, 0, false); /* sets demote */
784 /*
785 * Ordinarily, we would call dlm and its callback would call
786 * finish_xmote, which would call state_change() to the new state.
787 * Since we withdrew, we won't call dlm, so call state_change
788 * manually, but to the UNLOCKED state we desire.
789 */
790 state_change(gl, LM_ST_UNLOCKED);
791 /*
792 * We skip telling dlm to do the locking, so we won't get a
793 * reply that would otherwise clear GLF_LOCK. So we clear it here.
794 */
795 clear_bit(GLF_LOCK, &gl->gl_flags);
796 clear_bit(GLF_DEMOTE_IN_PROGRESS, &gl->gl_flags);
797 gfs2_glock_queue_work(gl, GL_GLOCK_DFT_HOLD);
798 goto out;
799 } else {
800 clear_bit(GLF_INVALIDATE_IN_PROGRESS, &gl->gl_flags);
801 }
802 }
803
804 if (sdp->sd_lockstruct.ls_ops->lm_lock) {
805 /* lock_dlm */
806 ret = sdp->sd_lockstruct.ls_ops->lm_lock(gl, target, lck_flags);
807 if (ret == -EINVAL && gl->gl_target == LM_ST_UNLOCKED &&
808 target == LM_ST_UNLOCKED &&
809 test_bit(SDF_SKIP_DLM_UNLOCK, &sdp->sd_flags)) {
810 finish_xmote(gl, target);
811 gfs2_glock_queue_work(gl, 0);
812 } else if (ret) {
813 fs_err(sdp, "lm_lock ret %d\n", ret);
814 GLOCK_BUG_ON(gl, !gfs2_withdrawing_or_withdrawn(sdp));
815 }
816 } else { /* lock_nolock */
817 finish_xmote(gl, target);
818 gfs2_glock_queue_work(gl, 0);
819 }
820out:
821 spin_lock(&gl->gl_lockref.lock);
822}
823
824/**
825 * run_queue - do all outstanding tasks related to a glock
826 * @gl: The glock in question
827 * @nonblock: True if we must not block in run_queue
828 *
829 */
830
831static void run_queue(struct gfs2_glock *gl, const int nonblock)
832__releases(&gl->gl_lockref.lock)
833__acquires(&gl->gl_lockref.lock)
834{
835 struct gfs2_holder *gh = NULL;
836
837 if (test_and_set_bit(GLF_LOCK, &gl->gl_flags))
838 return;
839
840 GLOCK_BUG_ON(gl, test_bit(GLF_DEMOTE_IN_PROGRESS, &gl->gl_flags));
841
842 if (test_bit(GLF_DEMOTE, &gl->gl_flags) &&
843 gl->gl_demote_state != gl->gl_state) {
844 if (find_first_holder(gl))
845 goto out_unlock;
846 if (nonblock)
847 goto out_sched;
848 set_bit(GLF_DEMOTE_IN_PROGRESS, &gl->gl_flags);
849 GLOCK_BUG_ON(gl, gl->gl_demote_state == LM_ST_EXCLUSIVE);
850 gl->gl_target = gl->gl_demote_state;
851 } else {
852 if (test_bit(GLF_DEMOTE, &gl->gl_flags))
853 gfs2_demote_wake(gl);
854 if (do_promote(gl))
855 goto out_unlock;
856 gh = find_first_waiter(gl);
857 gl->gl_target = gh->gh_state;
858 if (!(gh->gh_flags & (LM_FLAG_TRY | LM_FLAG_TRY_1CB)))
859 do_error(gl, 0); /* Fail queued try locks */
860 }
861 do_xmote(gl, gh, gl->gl_target);
862 return;
863
864out_sched:
865 clear_bit(GLF_LOCK, &gl->gl_flags);
866 smp_mb__after_atomic();
867 gl->gl_lockref.count++;
868 __gfs2_glock_queue_work(gl, 0);
869 return;
870
871out_unlock:
872 clear_bit(GLF_LOCK, &gl->gl_flags);
873 smp_mb__after_atomic();
874 return;
875}
876
877/**
878 * glock_set_object - set the gl_object field of a glock
879 * @gl: the glock
880 * @object: the object
881 */
882void glock_set_object(struct gfs2_glock *gl, void *object)
883{
884 void *prev_object;
885
886 spin_lock(&gl->gl_lockref.lock);
887 prev_object = gl->gl_object;
888 gl->gl_object = object;
889 spin_unlock(&gl->gl_lockref.lock);
890 if (gfs2_assert_warn(gl->gl_name.ln_sbd, prev_object == NULL)) {
891 pr_warn("glock=%u/%llx\n",
892 gl->gl_name.ln_type,
893 (unsigned long long)gl->gl_name.ln_number);
894 gfs2_dump_glock(NULL, gl, true);
895 }
896}
897
898/**
899 * glock_clear_object - clear the gl_object field of a glock
900 * @gl: the glock
901 * @object: object the glock currently points at
902 */
903void glock_clear_object(struct gfs2_glock *gl, void *object)
904{
905 void *prev_object;
906
907 spin_lock(&gl->gl_lockref.lock);
908 prev_object = gl->gl_object;
909 gl->gl_object = NULL;
910 spin_unlock(&gl->gl_lockref.lock);
911 if (gfs2_assert_warn(gl->gl_name.ln_sbd, prev_object == object)) {
912 pr_warn("glock=%u/%llx\n",
913 gl->gl_name.ln_type,
914 (unsigned long long)gl->gl_name.ln_number);
915 gfs2_dump_glock(NULL, gl, true);
916 }
917}
918
919void gfs2_inode_remember_delete(struct gfs2_glock *gl, u64 generation)
920{
921 struct gfs2_inode_lvb *ri = (void *)gl->gl_lksb.sb_lvbptr;
922
923 if (ri->ri_magic == 0)
924 ri->ri_magic = cpu_to_be32(GFS2_MAGIC);
925 if (ri->ri_magic == cpu_to_be32(GFS2_MAGIC))
926 ri->ri_generation_deleted = cpu_to_be64(generation);
927}
928
929bool gfs2_inode_already_deleted(struct gfs2_glock *gl, u64 generation)
930{
931 struct gfs2_inode_lvb *ri = (void *)gl->gl_lksb.sb_lvbptr;
932
933 if (ri->ri_magic != cpu_to_be32(GFS2_MAGIC))
934 return false;
935 return generation <= be64_to_cpu(ri->ri_generation_deleted);
936}
937
938static void gfs2_glock_poke(struct gfs2_glock *gl)
939{
940 int flags = LM_FLAG_TRY_1CB | LM_FLAG_ANY | GL_SKIP;
941 struct gfs2_holder gh;
942 int error;
943
944 __gfs2_holder_init(gl, LM_ST_SHARED, flags, &gh, _RET_IP_);
945 error = gfs2_glock_nq(&gh);
946 if (!error)
947 gfs2_glock_dq(&gh);
948 gfs2_holder_uninit(&gh);
949}
950
951static bool gfs2_try_evict(struct gfs2_glock *gl)
952{
953 struct gfs2_inode *ip;
954 bool evicted = false;
955
956 /*
957 * If there is contention on the iopen glock and we have an inode, try
958 * to grab and release the inode so that it can be evicted. This will
959 * allow the remote node to go ahead and delete the inode without us
960 * having to do it, which will avoid rgrp glock thrashing.
961 *
962 * The remote node is likely still holding the corresponding inode
963 * glock, so it will run before we get to verify that the delete has
964 * happened below.
965 */
966 spin_lock(&gl->gl_lockref.lock);
967 ip = gl->gl_object;
968 if (ip && !igrab(&ip->i_inode))
969 ip = NULL;
970 spin_unlock(&gl->gl_lockref.lock);
971 if (ip) {
972 gl->gl_no_formal_ino = ip->i_no_formal_ino;
973 set_bit(GIF_DEFERRED_DELETE, &ip->i_flags);
974 d_prune_aliases(&ip->i_inode);
975 iput(&ip->i_inode);
976
977 /* If the inode was evicted, gl->gl_object will now be NULL. */
978 spin_lock(&gl->gl_lockref.lock);
979 ip = gl->gl_object;
980 if (ip) {
981 clear_bit(GIF_DEFERRED_DELETE, &ip->i_flags);
982 if (!igrab(&ip->i_inode))
983 ip = NULL;
984 }
985 spin_unlock(&gl->gl_lockref.lock);
986 if (ip) {
987 gfs2_glock_poke(ip->i_gl);
988 iput(&ip->i_inode);
989 }
990 evicted = !ip;
991 }
992 return evicted;
993}
994
995bool gfs2_queue_try_to_evict(struct gfs2_glock *gl)
996{
997 struct gfs2_sbd *sdp = gl->gl_name.ln_sbd;
998
999 if (test_and_set_bit(GLF_TRY_TO_EVICT, &gl->gl_flags))
1000 return false;
1001 return queue_delayed_work(sdp->sd_delete_wq,
1002 &gl->gl_delete, 0);
1003}
1004
1005static bool gfs2_queue_verify_evict(struct gfs2_glock *gl)
1006{
1007 struct gfs2_sbd *sdp = gl->gl_name.ln_sbd;
1008
1009 if (test_and_set_bit(GLF_VERIFY_EVICT, &gl->gl_flags))
1010 return false;
1011 return queue_delayed_work(sdp->sd_delete_wq,
1012 &gl->gl_delete, 5 * HZ);
1013}
1014
1015static void delete_work_func(struct work_struct *work)
1016{
1017 struct delayed_work *dwork = to_delayed_work(work);
1018 struct gfs2_glock *gl = container_of(dwork, struct gfs2_glock, gl_delete);
1019 struct gfs2_sbd *sdp = gl->gl_name.ln_sbd;
1020 struct inode *inode;
1021 u64 no_addr = gl->gl_name.ln_number;
1022
1023 if (test_and_clear_bit(GLF_TRY_TO_EVICT, &gl->gl_flags)) {
1024 /*
1025 * If we can evict the inode, give the remote node trying to
1026 * delete the inode some time before verifying that the delete
1027 * has happened. Otherwise, if we cause contention on the inode glock
1028 * immediately, the remote node will think that we still have
1029 * the inode in use, and so it will give up waiting.
1030 *
1031 * If we can't evict the inode, signal to the remote node that
1032 * the inode is still in use. We'll later try to delete the
1033 * inode locally in gfs2_evict_inode.
1034 *
1035 * FIXME: We only need to verify that the remote node has
1036 * deleted the inode because nodes before this remote delete
1037 * rework won't cooperate. At a later time, when we no longer
1038 * care about compatibility with such nodes, we can skip this
1039 * step entirely.
1040 */
1041 if (gfs2_try_evict(gl)) {
1042 if (test_bit(SDF_KILL, &sdp->sd_flags))
1043 goto out;
1044 if (gfs2_queue_verify_evict(gl))
1045 return;
1046 }
1047 goto out;
1048 }
1049
1050 if (test_and_clear_bit(GLF_VERIFY_EVICT, &gl->gl_flags)) {
1051 inode = gfs2_lookup_by_inum(sdp, no_addr, gl->gl_no_formal_ino,
1052 GFS2_BLKST_UNLINKED);
1053 if (IS_ERR(inode)) {
1054 if (PTR_ERR(inode) == -EAGAIN &&
1055 !test_bit(SDF_KILL, &sdp->sd_flags) &&
1056 gfs2_queue_verify_evict(gl))
1057 return;
1058 } else {
1059 d_prune_aliases(inode);
1060 iput(inode);
1061 }
1062 }
1063
1064out:
1065 gfs2_glock_put(gl);
1066}
1067
1068static void glock_work_func(struct work_struct *work)
1069{
1070 unsigned long delay = 0;
1071 struct gfs2_glock *gl = container_of(work, struct gfs2_glock, gl_work.work);
1072 unsigned int drop_refs = 1;
1073
1074 if (test_and_clear_bit(GLF_REPLY_PENDING, &gl->gl_flags)) {
1075 finish_xmote(gl, gl->gl_reply);
1076 drop_refs++;
1077 }
1078 spin_lock(&gl->gl_lockref.lock);
1079 if (test_bit(GLF_PENDING_DEMOTE, &gl->gl_flags) &&
1080 gl->gl_state != LM_ST_UNLOCKED &&
1081 gl->gl_demote_state != LM_ST_EXCLUSIVE) {
1082 unsigned long holdtime, now = jiffies;
1083
1084 holdtime = gl->gl_tchange + gl->gl_hold_time;
1085 if (time_before(now, holdtime))
1086 delay = holdtime - now;
1087
1088 if (!delay) {
1089 clear_bit(GLF_PENDING_DEMOTE, &gl->gl_flags);
1090 gfs2_set_demote(gl);
1091 }
1092 }
1093 run_queue(gl, 0);
1094 if (delay) {
1095 /* Keep one glock reference for the work we requeue. */
1096 drop_refs--;
1097 if (gl->gl_name.ln_type != LM_TYPE_INODE)
1098 delay = 0;
1099 __gfs2_glock_queue_work(gl, delay);
1100 }
1101
1102 /*
1103 * Drop the remaining glock references manually here. (Mind that
1104 * __gfs2_glock_queue_work depends on the lockref spinlock begin held
1105 * here as well.)
1106 */
1107 gl->gl_lockref.count -= drop_refs;
1108 if (!gl->gl_lockref.count) {
1109 __gfs2_glock_put(gl);
1110 return;
1111 }
1112 spin_unlock(&gl->gl_lockref.lock);
1113}
1114
1115static struct gfs2_glock *find_insert_glock(struct lm_lockname *name,
1116 struct gfs2_glock *new)
1117{
1118 struct wait_glock_queue wait;
1119 wait_queue_head_t *wq = glock_waitqueue(name);
1120 struct gfs2_glock *gl;
1121
1122 wait.name = name;
1123 init_wait(&wait.wait);
1124 wait.wait.func = glock_wake_function;
1125
1126again:
1127 prepare_to_wait(wq, &wait.wait, TASK_UNINTERRUPTIBLE);
1128 rcu_read_lock();
1129 if (new) {
1130 gl = rhashtable_lookup_get_insert_fast(&gl_hash_table,
1131 &new->gl_node, ht_parms);
1132 if (IS_ERR(gl))
1133 goto out;
1134 } else {
1135 gl = rhashtable_lookup_fast(&gl_hash_table,
1136 name, ht_parms);
1137 }
1138 if (gl && !lockref_get_not_dead(&gl->gl_lockref)) {
1139 rcu_read_unlock();
1140 schedule();
1141 goto again;
1142 }
1143out:
1144 rcu_read_unlock();
1145 finish_wait(wq, &wait.wait);
1146 return gl;
1147}
1148
1149/**
1150 * gfs2_glock_get() - Get a glock, or create one if one doesn't exist
1151 * @sdp: The GFS2 superblock
1152 * @number: the lock number
1153 * @glops: The glock_operations to use
1154 * @create: If 0, don't create the glock if it doesn't exist
1155 * @glp: the glock is returned here
1156 *
1157 * This does not lock a glock, just finds/creates structures for one.
1158 *
1159 * Returns: errno
1160 */
1161
1162int gfs2_glock_get(struct gfs2_sbd *sdp, u64 number,
1163 const struct gfs2_glock_operations *glops, int create,
1164 struct gfs2_glock **glp)
1165{
1166 struct super_block *s = sdp->sd_vfs;
1167 struct lm_lockname name = { .ln_number = number,
1168 .ln_type = glops->go_type,
1169 .ln_sbd = sdp };
1170 struct gfs2_glock *gl, *tmp;
1171 struct address_space *mapping;
1172 int ret = 0;
1173
1174 gl = find_insert_glock(&name, NULL);
1175 if (gl) {
1176 *glp = gl;
1177 return 0;
1178 }
1179 if (!create)
1180 return -ENOENT;
1181
1182 if (glops->go_flags & GLOF_ASPACE) {
1183 struct gfs2_glock_aspace *gla =
1184 kmem_cache_alloc(gfs2_glock_aspace_cachep, GFP_NOFS);
1185 if (!gla)
1186 return -ENOMEM;
1187 gl = &gla->glock;
1188 } else {
1189 gl = kmem_cache_alloc(gfs2_glock_cachep, GFP_NOFS);
1190 if (!gl)
1191 return -ENOMEM;
1192 }
1193 memset(&gl->gl_lksb, 0, sizeof(struct dlm_lksb));
1194 gl->gl_ops = glops;
1195
1196 if (glops->go_flags & GLOF_LVB) {
1197 gl->gl_lksb.sb_lvbptr = kzalloc(GDLM_LVB_SIZE, GFP_NOFS);
1198 if (!gl->gl_lksb.sb_lvbptr) {
1199 gfs2_glock_dealloc(&gl->gl_rcu);
1200 return -ENOMEM;
1201 }
1202 }
1203
1204 atomic_inc(&sdp->sd_glock_disposal);
1205 gl->gl_node.next = NULL;
1206 gl->gl_flags = glops->go_instantiate ? BIT(GLF_INSTANTIATE_NEEDED) : 0;
1207 gl->gl_name = name;
1208 lockdep_set_subclass(&gl->gl_lockref.lock, glops->go_subclass);
1209 gl->gl_lockref.count = 1;
1210 gl->gl_state = LM_ST_UNLOCKED;
1211 gl->gl_target = LM_ST_UNLOCKED;
1212 gl->gl_demote_state = LM_ST_EXCLUSIVE;
1213 gl->gl_dstamp = 0;
1214 preempt_disable();
1215 /* We use the global stats to estimate the initial per-glock stats */
1216 gl->gl_stats = this_cpu_ptr(sdp->sd_lkstats)->lkstats[glops->go_type];
1217 preempt_enable();
1218 gl->gl_stats.stats[GFS2_LKS_DCOUNT] = 0;
1219 gl->gl_stats.stats[GFS2_LKS_QCOUNT] = 0;
1220 gl->gl_tchange = jiffies;
1221 gl->gl_object = NULL;
1222 gl->gl_hold_time = GL_GLOCK_DFT_HOLD;
1223 INIT_DELAYED_WORK(&gl->gl_work, glock_work_func);
1224 if (gl->gl_name.ln_type == LM_TYPE_IOPEN)
1225 INIT_DELAYED_WORK(&gl->gl_delete, delete_work_func);
1226
1227 mapping = gfs2_glock2aspace(gl);
1228 if (mapping) {
1229 mapping->a_ops = &gfs2_meta_aops;
1230 mapping->host = s->s_bdev->bd_inode;
1231 mapping->flags = 0;
1232 mapping_set_gfp_mask(mapping, GFP_NOFS);
1233 mapping->i_private_data = NULL;
1234 mapping->writeback_index = 0;
1235 }
1236
1237 tmp = find_insert_glock(&name, gl);
1238 if (!tmp) {
1239 *glp = gl;
1240 goto out;
1241 }
1242 if (IS_ERR(tmp)) {
1243 ret = PTR_ERR(tmp);
1244 goto out_free;
1245 }
1246 *glp = tmp;
1247
1248out_free:
1249 gfs2_glock_dealloc(&gl->gl_rcu);
1250 if (atomic_dec_and_test(&sdp->sd_glock_disposal))
1251 wake_up(&sdp->sd_kill_wait);
1252
1253out:
1254 return ret;
1255}
1256
1257/**
1258 * __gfs2_holder_init - initialize a struct gfs2_holder in the default way
1259 * @gl: the glock
1260 * @state: the state we're requesting
1261 * @flags: the modifier flags
1262 * @gh: the holder structure
1263 *
1264 */
1265
1266void __gfs2_holder_init(struct gfs2_glock *gl, unsigned int state, u16 flags,
1267 struct gfs2_holder *gh, unsigned long ip)
1268{
1269 INIT_LIST_HEAD(&gh->gh_list);
1270 gh->gh_gl = gfs2_glock_hold(gl);
1271 gh->gh_ip = ip;
1272 gh->gh_owner_pid = get_pid(task_pid(current));
1273 gh->gh_state = state;
1274 gh->gh_flags = flags;
1275 gh->gh_iflags = 0;
1276}
1277
1278/**
1279 * gfs2_holder_reinit - reinitialize a struct gfs2_holder so we can requeue it
1280 * @state: the state we're requesting
1281 * @flags: the modifier flags
1282 * @gh: the holder structure
1283 *
1284 * Don't mess with the glock.
1285 *
1286 */
1287
1288void gfs2_holder_reinit(unsigned int state, u16 flags, struct gfs2_holder *gh)
1289{
1290 gh->gh_state = state;
1291 gh->gh_flags = flags;
1292 gh->gh_iflags = 0;
1293 gh->gh_ip = _RET_IP_;
1294 put_pid(gh->gh_owner_pid);
1295 gh->gh_owner_pid = get_pid(task_pid(current));
1296}
1297
1298/**
1299 * gfs2_holder_uninit - uninitialize a holder structure (drop glock reference)
1300 * @gh: the holder structure
1301 *
1302 */
1303
1304void gfs2_holder_uninit(struct gfs2_holder *gh)
1305{
1306 put_pid(gh->gh_owner_pid);
1307 gfs2_glock_put(gh->gh_gl);
1308 gfs2_holder_mark_uninitialized(gh);
1309 gh->gh_ip = 0;
1310}
1311
1312static void gfs2_glock_update_hold_time(struct gfs2_glock *gl,
1313 unsigned long start_time)
1314{
1315 /* Have we waited longer that a second? */
1316 if (time_after(jiffies, start_time + HZ)) {
1317 /* Lengthen the minimum hold time. */
1318 gl->gl_hold_time = min(gl->gl_hold_time + GL_GLOCK_HOLD_INCR,
1319 GL_GLOCK_MAX_HOLD);
1320 }
1321}
1322
1323/**
1324 * gfs2_glock_holder_ready - holder is ready and its error code can be collected
1325 * @gh: the glock holder
1326 *
1327 * Called when a glock holder no longer needs to be waited for because it is
1328 * now either held (HIF_HOLDER set; gh_error == 0), or acquiring the lock has
1329 * failed (gh_error != 0).
1330 */
1331
1332int gfs2_glock_holder_ready(struct gfs2_holder *gh)
1333{
1334 if (gh->gh_error || (gh->gh_flags & GL_SKIP))
1335 return gh->gh_error;
1336 gh->gh_error = gfs2_instantiate(gh);
1337 if (gh->gh_error)
1338 gfs2_glock_dq(gh);
1339 return gh->gh_error;
1340}
1341
1342/**
1343 * gfs2_glock_wait - wait on a glock acquisition
1344 * @gh: the glock holder
1345 *
1346 * Returns: 0 on success
1347 */
1348
1349int gfs2_glock_wait(struct gfs2_holder *gh)
1350{
1351 unsigned long start_time = jiffies;
1352
1353 might_sleep();
1354 wait_on_bit(&gh->gh_iflags, HIF_WAIT, TASK_UNINTERRUPTIBLE);
1355 gfs2_glock_update_hold_time(gh->gh_gl, start_time);
1356 return gfs2_glock_holder_ready(gh);
1357}
1358
1359static int glocks_pending(unsigned int num_gh, struct gfs2_holder *ghs)
1360{
1361 int i;
1362
1363 for (i = 0; i < num_gh; i++)
1364 if (test_bit(HIF_WAIT, &ghs[i].gh_iflags))
1365 return 1;
1366 return 0;
1367}
1368
1369/**
1370 * gfs2_glock_async_wait - wait on multiple asynchronous glock acquisitions
1371 * @num_gh: the number of holders in the array
1372 * @ghs: the glock holder array
1373 *
1374 * Returns: 0 on success, meaning all glocks have been granted and are held.
1375 * -ESTALE if the request timed out, meaning all glocks were released,
1376 * and the caller should retry the operation.
1377 */
1378
1379int gfs2_glock_async_wait(unsigned int num_gh, struct gfs2_holder *ghs)
1380{
1381 struct gfs2_sbd *sdp = ghs[0].gh_gl->gl_name.ln_sbd;
1382 int i, ret = 0, timeout = 0;
1383 unsigned long start_time = jiffies;
1384
1385 might_sleep();
1386 /*
1387 * Total up the (minimum hold time * 2) of all glocks and use that to
1388 * determine the max amount of time we should wait.
1389 */
1390 for (i = 0; i < num_gh; i++)
1391 timeout += ghs[i].gh_gl->gl_hold_time << 1;
1392
1393 if (!wait_event_timeout(sdp->sd_async_glock_wait,
1394 !glocks_pending(num_gh, ghs), timeout)) {
1395 ret = -ESTALE; /* request timed out. */
1396 goto out;
1397 }
1398
1399 for (i = 0; i < num_gh; i++) {
1400 struct gfs2_holder *gh = &ghs[i];
1401 int ret2;
1402
1403 if (test_bit(HIF_HOLDER, &gh->gh_iflags)) {
1404 gfs2_glock_update_hold_time(gh->gh_gl,
1405 start_time);
1406 }
1407 ret2 = gfs2_glock_holder_ready(gh);
1408 if (!ret)
1409 ret = ret2;
1410 }
1411
1412out:
1413 if (ret) {
1414 for (i = 0; i < num_gh; i++) {
1415 struct gfs2_holder *gh = &ghs[i];
1416
1417 gfs2_glock_dq(gh);
1418 }
1419 }
1420 return ret;
1421}
1422
1423/**
1424 * handle_callback - process a demote request
1425 * @gl: the glock
1426 * @state: the state the caller wants us to change to
1427 * @delay: zero to demote immediately; otherwise pending demote
1428 * @remote: true if this came from a different cluster node
1429 *
1430 * There are only two requests that we are going to see in actual
1431 * practise: LM_ST_SHARED and LM_ST_UNLOCKED
1432 */
1433
1434static void handle_callback(struct gfs2_glock *gl, unsigned int state,
1435 unsigned long delay, bool remote)
1436{
1437 if (delay)
1438 set_bit(GLF_PENDING_DEMOTE, &gl->gl_flags);
1439 else
1440 gfs2_set_demote(gl);
1441 if (gl->gl_demote_state == LM_ST_EXCLUSIVE) {
1442 gl->gl_demote_state = state;
1443 gl->gl_demote_time = jiffies;
1444 } else if (gl->gl_demote_state != LM_ST_UNLOCKED &&
1445 gl->gl_demote_state != state) {
1446 gl->gl_demote_state = LM_ST_UNLOCKED;
1447 }
1448 if (gl->gl_ops->go_callback)
1449 gl->gl_ops->go_callback(gl, remote);
1450 trace_gfs2_demote_rq(gl, remote);
1451}
1452
1453void gfs2_print_dbg(struct seq_file *seq, const char *fmt, ...)
1454{
1455 struct va_format vaf;
1456 va_list args;
1457
1458 va_start(args, fmt);
1459
1460 if (seq) {
1461 seq_vprintf(seq, fmt, args);
1462 } else {
1463 vaf.fmt = fmt;
1464 vaf.va = &args;
1465
1466 pr_err("%pV", &vaf);
1467 }
1468
1469 va_end(args);
1470}
1471
1472static inline bool pid_is_meaningful(const struct gfs2_holder *gh)
1473{
1474 if (!(gh->gh_flags & GL_NOPID))
1475 return true;
1476 if (gh->gh_state == LM_ST_UNLOCKED)
1477 return true;
1478 return false;
1479}
1480
1481/**
1482 * add_to_queue - Add a holder to the wait queue (but look for recursion)
1483 * @gh: the holder structure to add
1484 *
1485 * Eventually we should move the recursive locking trap to a
1486 * debugging option or something like that. This is the fast
1487 * path and needs to have the minimum number of distractions.
1488 *
1489 */
1490
1491static inline void add_to_queue(struct gfs2_holder *gh)
1492__releases(&gl->gl_lockref.lock)
1493__acquires(&gl->gl_lockref.lock)
1494{
1495 struct gfs2_glock *gl = gh->gh_gl;
1496 struct gfs2_sbd *sdp = gl->gl_name.ln_sbd;
1497 struct list_head *insert_pt = NULL;
1498 struct gfs2_holder *gh2;
1499 int try_futile = 0;
1500
1501 GLOCK_BUG_ON(gl, gh->gh_owner_pid == NULL);
1502 if (test_and_set_bit(HIF_WAIT, &gh->gh_iflags))
1503 GLOCK_BUG_ON(gl, true);
1504
1505 if (gh->gh_flags & (LM_FLAG_TRY | LM_FLAG_TRY_1CB)) {
1506 if (test_bit(GLF_LOCK, &gl->gl_flags)) {
1507 struct gfs2_holder *current_gh;
1508
1509 current_gh = find_first_holder(gl);
1510 try_futile = !may_grant(gl, current_gh, gh);
1511 }
1512 if (test_bit(GLF_INVALIDATE_IN_PROGRESS, &gl->gl_flags))
1513 goto fail;
1514 }
1515
1516 list_for_each_entry(gh2, &gl->gl_holders, gh_list) {
1517 if (likely(gh2->gh_owner_pid != gh->gh_owner_pid))
1518 continue;
1519 if (gh->gh_gl->gl_ops->go_type == LM_TYPE_FLOCK)
1520 continue;
1521 if (!pid_is_meaningful(gh2))
1522 continue;
1523 goto trap_recursive;
1524 }
1525 list_for_each_entry(gh2, &gl->gl_holders, gh_list) {
1526 if (try_futile &&
1527 !(gh2->gh_flags & (LM_FLAG_TRY | LM_FLAG_TRY_1CB))) {
1528fail:
1529 gh->gh_error = GLR_TRYFAILED;
1530 gfs2_holder_wake(gh);
1531 return;
1532 }
1533 if (test_bit(HIF_HOLDER, &gh2->gh_iflags))
1534 continue;
1535 }
1536 trace_gfs2_glock_queue(gh, 1);
1537 gfs2_glstats_inc(gl, GFS2_LKS_QCOUNT);
1538 gfs2_sbstats_inc(gl, GFS2_LKS_QCOUNT);
1539 if (likely(insert_pt == NULL)) {
1540 list_add_tail(&gh->gh_list, &gl->gl_holders);
1541 return;
1542 }
1543 list_add_tail(&gh->gh_list, insert_pt);
1544 spin_unlock(&gl->gl_lockref.lock);
1545 if (sdp->sd_lockstruct.ls_ops->lm_cancel)
1546 sdp->sd_lockstruct.ls_ops->lm_cancel(gl);
1547 spin_lock(&gl->gl_lockref.lock);
1548 return;
1549
1550trap_recursive:
1551 fs_err(sdp, "original: %pSR\n", (void *)gh2->gh_ip);
1552 fs_err(sdp, "pid: %d\n", pid_nr(gh2->gh_owner_pid));
1553 fs_err(sdp, "lock type: %d req lock state : %d\n",
1554 gh2->gh_gl->gl_name.ln_type, gh2->gh_state);
1555 fs_err(sdp, "new: %pSR\n", (void *)gh->gh_ip);
1556 fs_err(sdp, "pid: %d\n", pid_nr(gh->gh_owner_pid));
1557 fs_err(sdp, "lock type: %d req lock state : %d\n",
1558 gh->gh_gl->gl_name.ln_type, gh->gh_state);
1559 gfs2_dump_glock(NULL, gl, true);
1560 BUG();
1561}
1562
1563/**
1564 * gfs2_glock_nq - enqueue a struct gfs2_holder onto a glock (acquire a glock)
1565 * @gh: the holder structure
1566 *
1567 * if (gh->gh_flags & GL_ASYNC), this never returns an error
1568 *
1569 * Returns: 0, GLR_TRYFAILED, or errno on failure
1570 */
1571
1572int gfs2_glock_nq(struct gfs2_holder *gh)
1573{
1574 struct gfs2_glock *gl = gh->gh_gl;
1575 int error;
1576
1577 if (glock_blocked_by_withdraw(gl) && !(gh->gh_flags & LM_FLAG_NOEXP))
1578 return -EIO;
1579
1580 if (gh->gh_flags & GL_NOBLOCK) {
1581 struct gfs2_holder *current_gh;
1582
1583 error = -ECHILD;
1584 spin_lock(&gl->gl_lockref.lock);
1585 if (find_last_waiter(gl))
1586 goto unlock;
1587 current_gh = find_first_holder(gl);
1588 if (!may_grant(gl, current_gh, gh))
1589 goto unlock;
1590 set_bit(HIF_HOLDER, &gh->gh_iflags);
1591 list_add_tail(&gh->gh_list, &gl->gl_holders);
1592 trace_gfs2_promote(gh);
1593 error = 0;
1594unlock:
1595 spin_unlock(&gl->gl_lockref.lock);
1596 return error;
1597 }
1598
1599 if (test_bit(GLF_LRU, &gl->gl_flags))
1600 gfs2_glock_remove_from_lru(gl);
1601
1602 gh->gh_error = 0;
1603 spin_lock(&gl->gl_lockref.lock);
1604 add_to_queue(gh);
1605 if (unlikely((LM_FLAG_NOEXP & gh->gh_flags) &&
1606 test_and_clear_bit(GLF_FROZEN, &gl->gl_flags))) {
1607 set_bit(GLF_REPLY_PENDING, &gl->gl_flags);
1608 gl->gl_lockref.count++;
1609 __gfs2_glock_queue_work(gl, 0);
1610 }
1611 run_queue(gl, 1);
1612 spin_unlock(&gl->gl_lockref.lock);
1613
1614 error = 0;
1615 if (!(gh->gh_flags & GL_ASYNC))
1616 error = gfs2_glock_wait(gh);
1617
1618 return error;
1619}
1620
1621/**
1622 * gfs2_glock_poll - poll to see if an async request has been completed
1623 * @gh: the holder
1624 *
1625 * Returns: 1 if the request is ready to be gfs2_glock_wait()ed on
1626 */
1627
1628int gfs2_glock_poll(struct gfs2_holder *gh)
1629{
1630 return test_bit(HIF_WAIT, &gh->gh_iflags) ? 0 : 1;
1631}
1632
1633static inline bool needs_demote(struct gfs2_glock *gl)
1634{
1635 return (test_bit(GLF_DEMOTE, &gl->gl_flags) ||
1636 test_bit(GLF_PENDING_DEMOTE, &gl->gl_flags));
1637}
1638
1639static void __gfs2_glock_dq(struct gfs2_holder *gh)
1640{
1641 struct gfs2_glock *gl = gh->gh_gl;
1642 unsigned delay = 0;
1643 int fast_path = 0;
1644
1645 /*
1646 * This holder should not be cached, so mark it for demote.
1647 * Note: this should be done before the check for needs_demote
1648 * below.
1649 */
1650 if (gh->gh_flags & GL_NOCACHE)
1651 handle_callback(gl, LM_ST_UNLOCKED, 0, false);
1652
1653 list_del_init(&gh->gh_list);
1654 clear_bit(HIF_HOLDER, &gh->gh_iflags);
1655 trace_gfs2_glock_queue(gh, 0);
1656
1657 /*
1658 * If there hasn't been a demote request we are done.
1659 * (Let the remaining holders, if any, keep holding it.)
1660 */
1661 if (!needs_demote(gl)) {
1662 if (list_empty(&gl->gl_holders))
1663 fast_path = 1;
1664 }
1665
1666 if (!test_bit(GLF_LFLUSH, &gl->gl_flags) && demote_ok(gl))
1667 gfs2_glock_add_to_lru(gl);
1668
1669 if (unlikely(!fast_path)) {
1670 gl->gl_lockref.count++;
1671 if (test_bit(GLF_PENDING_DEMOTE, &gl->gl_flags) &&
1672 !test_bit(GLF_DEMOTE, &gl->gl_flags) &&
1673 gl->gl_name.ln_type == LM_TYPE_INODE)
1674 delay = gl->gl_hold_time;
1675 __gfs2_glock_queue_work(gl, delay);
1676 }
1677}
1678
1679/**
1680 * gfs2_glock_dq - dequeue a struct gfs2_holder from a glock (release a glock)
1681 * @gh: the glock holder
1682 *
1683 */
1684void gfs2_glock_dq(struct gfs2_holder *gh)
1685{
1686 struct gfs2_glock *gl = gh->gh_gl;
1687 struct gfs2_sbd *sdp = gl->gl_name.ln_sbd;
1688
1689 spin_lock(&gl->gl_lockref.lock);
1690 if (!gfs2_holder_queued(gh)) {
1691 /*
1692 * May have already been dequeued because the locking request
1693 * was GL_ASYNC and it has failed in the meantime.
1694 */
1695 goto out;
1696 }
1697
1698 if (list_is_first(&gh->gh_list, &gl->gl_holders) &&
1699 !test_bit(HIF_HOLDER, &gh->gh_iflags)) {
1700 spin_unlock(&gl->gl_lockref.lock);
1701 gl->gl_name.ln_sbd->sd_lockstruct.ls_ops->lm_cancel(gl);
1702 wait_on_bit(&gh->gh_iflags, HIF_WAIT, TASK_UNINTERRUPTIBLE);
1703 spin_lock(&gl->gl_lockref.lock);
1704 }
1705
1706 /*
1707 * If we're in the process of file system withdraw, we cannot just
1708 * dequeue any glocks until our journal is recovered, lest we introduce
1709 * file system corruption. We need two exceptions to this rule: We need
1710 * to allow unlocking of nondisk glocks and the glock for our own
1711 * journal that needs recovery.
1712 */
1713 if (test_bit(SDF_WITHDRAW_RECOVERY, &sdp->sd_flags) &&
1714 glock_blocked_by_withdraw(gl) &&
1715 gh->gh_gl != sdp->sd_jinode_gl) {
1716 sdp->sd_glock_dqs_held++;
1717 spin_unlock(&gl->gl_lockref.lock);
1718 might_sleep();
1719 wait_on_bit(&sdp->sd_flags, SDF_WITHDRAW_RECOVERY,
1720 TASK_UNINTERRUPTIBLE);
1721 spin_lock(&gl->gl_lockref.lock);
1722 }
1723
1724 __gfs2_glock_dq(gh);
1725out:
1726 spin_unlock(&gl->gl_lockref.lock);
1727}
1728
1729void gfs2_glock_dq_wait(struct gfs2_holder *gh)
1730{
1731 struct gfs2_glock *gl = gh->gh_gl;
1732 gfs2_glock_dq(gh);
1733 might_sleep();
1734 wait_on_bit(&gl->gl_flags, GLF_DEMOTE, TASK_UNINTERRUPTIBLE);
1735}
1736
1737/**
1738 * gfs2_glock_dq_uninit - dequeue a holder from a glock and initialize it
1739 * @gh: the holder structure
1740 *
1741 */
1742
1743void gfs2_glock_dq_uninit(struct gfs2_holder *gh)
1744{
1745 gfs2_glock_dq(gh);
1746 gfs2_holder_uninit(gh);
1747}
1748
1749/**
1750 * gfs2_glock_nq_num - acquire a glock based on lock number
1751 * @sdp: the filesystem
1752 * @number: the lock number
1753 * @glops: the glock operations for the type of glock
1754 * @state: the state to acquire the glock in
1755 * @flags: modifier flags for the acquisition
1756 * @gh: the struct gfs2_holder
1757 *
1758 * Returns: errno
1759 */
1760
1761int gfs2_glock_nq_num(struct gfs2_sbd *sdp, u64 number,
1762 const struct gfs2_glock_operations *glops,
1763 unsigned int state, u16 flags, struct gfs2_holder *gh)
1764{
1765 struct gfs2_glock *gl;
1766 int error;
1767
1768 error = gfs2_glock_get(sdp, number, glops, CREATE, &gl);
1769 if (!error) {
1770 error = gfs2_glock_nq_init(gl, state, flags, gh);
1771 gfs2_glock_put(gl);
1772 }
1773
1774 return error;
1775}
1776
1777/**
1778 * glock_compare - Compare two struct gfs2_glock structures for sorting
1779 * @arg_a: the first structure
1780 * @arg_b: the second structure
1781 *
1782 */
1783
1784static int glock_compare(const void *arg_a, const void *arg_b)
1785{
1786 const struct gfs2_holder *gh_a = *(const struct gfs2_holder **)arg_a;
1787 const struct gfs2_holder *gh_b = *(const struct gfs2_holder **)arg_b;
1788 const struct lm_lockname *a = &gh_a->gh_gl->gl_name;
1789 const struct lm_lockname *b = &gh_b->gh_gl->gl_name;
1790
1791 if (a->ln_number > b->ln_number)
1792 return 1;
1793 if (a->ln_number < b->ln_number)
1794 return -1;
1795 BUG_ON(gh_a->gh_gl->gl_ops->go_type == gh_b->gh_gl->gl_ops->go_type);
1796 return 0;
1797}
1798
1799/**
1800 * nq_m_sync - synchronously acquire more than one glock in deadlock free order
1801 * @num_gh: the number of structures
1802 * @ghs: an array of struct gfs2_holder structures
1803 * @p: placeholder for the holder structure to pass back
1804 *
1805 * Returns: 0 on success (all glocks acquired),
1806 * errno on failure (no glocks acquired)
1807 */
1808
1809static int nq_m_sync(unsigned int num_gh, struct gfs2_holder *ghs,
1810 struct gfs2_holder **p)
1811{
1812 unsigned int x;
1813 int error = 0;
1814
1815 for (x = 0; x < num_gh; x++)
1816 p[x] = &ghs[x];
1817
1818 sort(p, num_gh, sizeof(struct gfs2_holder *), glock_compare, NULL);
1819
1820 for (x = 0; x < num_gh; x++) {
1821 error = gfs2_glock_nq(p[x]);
1822 if (error) {
1823 while (x--)
1824 gfs2_glock_dq(p[x]);
1825 break;
1826 }
1827 }
1828
1829 return error;
1830}
1831
1832/**
1833 * gfs2_glock_nq_m - acquire multiple glocks
1834 * @num_gh: the number of structures
1835 * @ghs: an array of struct gfs2_holder structures
1836 *
1837 * Returns: 0 on success (all glocks acquired),
1838 * errno on failure (no glocks acquired)
1839 */
1840
1841int gfs2_glock_nq_m(unsigned int num_gh, struct gfs2_holder *ghs)
1842{
1843 struct gfs2_holder *tmp[4];
1844 struct gfs2_holder **pph = tmp;
1845 int error = 0;
1846
1847 switch(num_gh) {
1848 case 0:
1849 return 0;
1850 case 1:
1851 return gfs2_glock_nq(ghs);
1852 default:
1853 if (num_gh <= 4)
1854 break;
1855 pph = kmalloc_array(num_gh, sizeof(struct gfs2_holder *),
1856 GFP_NOFS);
1857 if (!pph)
1858 return -ENOMEM;
1859 }
1860
1861 error = nq_m_sync(num_gh, ghs, pph);
1862
1863 if (pph != tmp)
1864 kfree(pph);
1865
1866 return error;
1867}
1868
1869/**
1870 * gfs2_glock_dq_m - release multiple glocks
1871 * @num_gh: the number of structures
1872 * @ghs: an array of struct gfs2_holder structures
1873 *
1874 */
1875
1876void gfs2_glock_dq_m(unsigned int num_gh, struct gfs2_holder *ghs)
1877{
1878 while (num_gh--)
1879 gfs2_glock_dq(&ghs[num_gh]);
1880}
1881
1882void gfs2_glock_cb(struct gfs2_glock *gl, unsigned int state)
1883{
1884 unsigned long delay = 0;
1885 unsigned long holdtime;
1886 unsigned long now = jiffies;
1887
1888 gfs2_glock_hold(gl);
1889 spin_lock(&gl->gl_lockref.lock);
1890 holdtime = gl->gl_tchange + gl->gl_hold_time;
1891 if (!list_empty(&gl->gl_holders) &&
1892 gl->gl_name.ln_type == LM_TYPE_INODE) {
1893 if (time_before(now, holdtime))
1894 delay = holdtime - now;
1895 if (test_bit(GLF_REPLY_PENDING, &gl->gl_flags))
1896 delay = gl->gl_hold_time;
1897 }
1898 handle_callback(gl, state, delay, true);
1899 __gfs2_glock_queue_work(gl, delay);
1900 spin_unlock(&gl->gl_lockref.lock);
1901}
1902
1903/**
1904 * gfs2_should_freeze - Figure out if glock should be frozen
1905 * @gl: The glock in question
1906 *
1907 * Glocks are not frozen if (a) the result of the dlm operation is
1908 * an error, (b) the locking operation was an unlock operation or
1909 * (c) if there is a "noexp" flagged request anywhere in the queue
1910 *
1911 * Returns: 1 if freezing should occur, 0 otherwise
1912 */
1913
1914static int gfs2_should_freeze(const struct gfs2_glock *gl)
1915{
1916 const struct gfs2_holder *gh;
1917
1918 if (gl->gl_reply & ~LM_OUT_ST_MASK)
1919 return 0;
1920 if (gl->gl_target == LM_ST_UNLOCKED)
1921 return 0;
1922
1923 list_for_each_entry(gh, &gl->gl_holders, gh_list) {
1924 if (test_bit(HIF_HOLDER, &gh->gh_iflags))
1925 continue;
1926 if (LM_FLAG_NOEXP & gh->gh_flags)
1927 return 0;
1928 }
1929
1930 return 1;
1931}
1932
1933/**
1934 * gfs2_glock_complete - Callback used by locking
1935 * @gl: Pointer to the glock
1936 * @ret: The return value from the dlm
1937 *
1938 * The gl_reply field is under the gl_lockref.lock lock so that it is ok
1939 * to use a bitfield shared with other glock state fields.
1940 */
1941
1942void gfs2_glock_complete(struct gfs2_glock *gl, int ret)
1943{
1944 struct lm_lockstruct *ls = &gl->gl_name.ln_sbd->sd_lockstruct;
1945
1946 spin_lock(&gl->gl_lockref.lock);
1947 gl->gl_reply = ret;
1948
1949 if (unlikely(test_bit(DFL_BLOCK_LOCKS, &ls->ls_recover_flags))) {
1950 if (gfs2_should_freeze(gl)) {
1951 set_bit(GLF_FROZEN, &gl->gl_flags);
1952 spin_unlock(&gl->gl_lockref.lock);
1953 return;
1954 }
1955 }
1956
1957 gl->gl_lockref.count++;
1958 set_bit(GLF_REPLY_PENDING, &gl->gl_flags);
1959 __gfs2_glock_queue_work(gl, 0);
1960 spin_unlock(&gl->gl_lockref.lock);
1961}
1962
1963static int glock_cmp(void *priv, const struct list_head *a,
1964 const struct list_head *b)
1965{
1966 struct gfs2_glock *gla, *glb;
1967
1968 gla = list_entry(a, struct gfs2_glock, gl_lru);
1969 glb = list_entry(b, struct gfs2_glock, gl_lru);
1970
1971 if (gla->gl_name.ln_number > glb->gl_name.ln_number)
1972 return 1;
1973 if (gla->gl_name.ln_number < glb->gl_name.ln_number)
1974 return -1;
1975
1976 return 0;
1977}
1978
1979/**
1980 * gfs2_dispose_glock_lru - Demote a list of glocks
1981 * @list: The list to dispose of
1982 *
1983 * Disposing of glocks may involve disk accesses, so that here we sort
1984 * the glocks by number (i.e. disk location of the inodes) so that if
1985 * there are any such accesses, they'll be sent in order (mostly).
1986 *
1987 * Must be called under the lru_lock, but may drop and retake this
1988 * lock. While the lru_lock is dropped, entries may vanish from the
1989 * list, but no new entries will appear on the list (since it is
1990 * private)
1991 */
1992
1993static void gfs2_dispose_glock_lru(struct list_head *list)
1994__releases(&lru_lock)
1995__acquires(&lru_lock)
1996{
1997 struct gfs2_glock *gl;
1998
1999 list_sort(NULL, list, glock_cmp);
2000
2001 while(!list_empty(list)) {
2002 gl = list_first_entry(list, struct gfs2_glock, gl_lru);
2003 list_del_init(&gl->gl_lru);
2004 clear_bit(GLF_LRU, &gl->gl_flags);
2005 if (!spin_trylock(&gl->gl_lockref.lock)) {
2006add_back_to_lru:
2007 list_add(&gl->gl_lru, &lru_list);
2008 set_bit(GLF_LRU, &gl->gl_flags);
2009 atomic_inc(&lru_count);
2010 continue;
2011 }
2012 if (test_and_set_bit(GLF_LOCK, &gl->gl_flags)) {
2013 spin_unlock(&gl->gl_lockref.lock);
2014 goto add_back_to_lru;
2015 }
2016 gl->gl_lockref.count++;
2017 if (demote_ok(gl))
2018 handle_callback(gl, LM_ST_UNLOCKED, 0, false);
2019 WARN_ON(!test_and_clear_bit(GLF_LOCK, &gl->gl_flags));
2020 __gfs2_glock_queue_work(gl, 0);
2021 spin_unlock(&gl->gl_lockref.lock);
2022 cond_resched_lock(&lru_lock);
2023 }
2024}
2025
2026/**
2027 * gfs2_scan_glock_lru - Scan the LRU looking for locks to demote
2028 * @nr: The number of entries to scan
2029 *
2030 * This function selects the entries on the LRU which are able to
2031 * be demoted, and then kicks off the process by calling
2032 * gfs2_dispose_glock_lru() above.
2033 */
2034
2035static long gfs2_scan_glock_lru(int nr)
2036{
2037 struct gfs2_glock *gl, *next;
2038 LIST_HEAD(dispose);
2039 long freed = 0;
2040
2041 spin_lock(&lru_lock);
2042 list_for_each_entry_safe(gl, next, &lru_list, gl_lru) {
2043 if (nr-- <= 0)
2044 break;
2045 /* Test for being demotable */
2046 if (!test_bit(GLF_LOCK, &gl->gl_flags)) {
2047 if (!spin_trylock(&gl->gl_lockref.lock))
2048 continue;
2049 if (gl->gl_lockref.count <= 1 &&
2050 (gl->gl_state == LM_ST_UNLOCKED ||
2051 demote_ok(gl))) {
2052 list_move(&gl->gl_lru, &dispose);
2053 atomic_dec(&lru_count);
2054 freed++;
2055 }
2056 spin_unlock(&gl->gl_lockref.lock);
2057 }
2058 }
2059 if (!list_empty(&dispose))
2060 gfs2_dispose_glock_lru(&dispose);
2061 spin_unlock(&lru_lock);
2062
2063 return freed;
2064}
2065
2066static unsigned long gfs2_glock_shrink_scan(struct shrinker *shrink,
2067 struct shrink_control *sc)
2068{
2069 if (!(sc->gfp_mask & __GFP_FS))
2070 return SHRINK_STOP;
2071 return gfs2_scan_glock_lru(sc->nr_to_scan);
2072}
2073
2074static unsigned long gfs2_glock_shrink_count(struct shrinker *shrink,
2075 struct shrink_control *sc)
2076{
2077 return vfs_pressure_ratio(atomic_read(&lru_count));
2078}
2079
2080static struct shrinker *glock_shrinker;
2081
2082/**
2083 * glock_hash_walk - Call a function for glock in a hash bucket
2084 * @examiner: the function
2085 * @sdp: the filesystem
2086 *
2087 * Note that the function can be called multiple times on the same
2088 * object. So the user must ensure that the function can cope with
2089 * that.
2090 */
2091
2092static void glock_hash_walk(glock_examiner examiner, const struct gfs2_sbd *sdp)
2093{
2094 struct gfs2_glock *gl;
2095 struct rhashtable_iter iter;
2096
2097 rhashtable_walk_enter(&gl_hash_table, &iter);
2098
2099 do {
2100 rhashtable_walk_start(&iter);
2101
2102 while ((gl = rhashtable_walk_next(&iter)) && !IS_ERR(gl)) {
2103 if (gl->gl_name.ln_sbd == sdp)
2104 examiner(gl);
2105 }
2106
2107 rhashtable_walk_stop(&iter);
2108 } while (cond_resched(), gl == ERR_PTR(-EAGAIN));
2109
2110 rhashtable_walk_exit(&iter);
2111}
2112
2113void gfs2_cancel_delete_work(struct gfs2_glock *gl)
2114{
2115 clear_bit(GLF_TRY_TO_EVICT, &gl->gl_flags);
2116 clear_bit(GLF_VERIFY_EVICT, &gl->gl_flags);
2117 if (cancel_delayed_work(&gl->gl_delete))
2118 gfs2_glock_put(gl);
2119}
2120
2121static void flush_delete_work(struct gfs2_glock *gl)
2122{
2123 if (gl->gl_name.ln_type == LM_TYPE_IOPEN) {
2124 struct gfs2_sbd *sdp = gl->gl_name.ln_sbd;
2125
2126 if (cancel_delayed_work(&gl->gl_delete)) {
2127 queue_delayed_work(sdp->sd_delete_wq,
2128 &gl->gl_delete, 0);
2129 }
2130 }
2131}
2132
2133void gfs2_flush_delete_work(struct gfs2_sbd *sdp)
2134{
2135 glock_hash_walk(flush_delete_work, sdp);
2136 flush_workqueue(sdp->sd_delete_wq);
2137}
2138
2139/**
2140 * thaw_glock - thaw out a glock which has an unprocessed reply waiting
2141 * @gl: The glock to thaw
2142 *
2143 */
2144
2145static void thaw_glock(struct gfs2_glock *gl)
2146{
2147 if (!test_and_clear_bit(GLF_FROZEN, &gl->gl_flags))
2148 return;
2149 if (!lockref_get_not_dead(&gl->gl_lockref))
2150 return;
2151 set_bit(GLF_REPLY_PENDING, &gl->gl_flags);
2152 gfs2_glock_queue_work(gl, 0);
2153}
2154
2155/**
2156 * clear_glock - look at a glock and see if we can free it from glock cache
2157 * @gl: the glock to look at
2158 *
2159 */
2160
2161static void clear_glock(struct gfs2_glock *gl)
2162{
2163 gfs2_glock_remove_from_lru(gl);
2164
2165 spin_lock(&gl->gl_lockref.lock);
2166 if (!__lockref_is_dead(&gl->gl_lockref)) {
2167 gl->gl_lockref.count++;
2168 if (gl->gl_state != LM_ST_UNLOCKED)
2169 handle_callback(gl, LM_ST_UNLOCKED, 0, false);
2170 __gfs2_glock_queue_work(gl, 0);
2171 }
2172 spin_unlock(&gl->gl_lockref.lock);
2173}
2174
2175/**
2176 * gfs2_glock_thaw - Thaw any frozen glocks
2177 * @sdp: The super block
2178 *
2179 */
2180
2181void gfs2_glock_thaw(struct gfs2_sbd *sdp)
2182{
2183 glock_hash_walk(thaw_glock, sdp);
2184}
2185
2186static void dump_glock(struct seq_file *seq, struct gfs2_glock *gl, bool fsid)
2187{
2188 spin_lock(&gl->gl_lockref.lock);
2189 gfs2_dump_glock(seq, gl, fsid);
2190 spin_unlock(&gl->gl_lockref.lock);
2191}
2192
2193static void dump_glock_func(struct gfs2_glock *gl)
2194{
2195 dump_glock(NULL, gl, true);
2196}
2197
2198static void withdraw_dq(struct gfs2_glock *gl)
2199{
2200 spin_lock(&gl->gl_lockref.lock);
2201 if (!__lockref_is_dead(&gl->gl_lockref) &&
2202 glock_blocked_by_withdraw(gl))
2203 do_error(gl, LM_OUT_ERROR); /* remove pending waiters */
2204 spin_unlock(&gl->gl_lockref.lock);
2205}
2206
2207void gfs2_gl_dq_holders(struct gfs2_sbd *sdp)
2208{
2209 glock_hash_walk(withdraw_dq, sdp);
2210}
2211
2212/**
2213 * gfs2_gl_hash_clear - Empty out the glock hash table
2214 * @sdp: the filesystem
2215 *
2216 * Called when unmounting the filesystem.
2217 */
2218
2219void gfs2_gl_hash_clear(struct gfs2_sbd *sdp)
2220{
2221 set_bit(SDF_SKIP_DLM_UNLOCK, &sdp->sd_flags);
2222 flush_workqueue(glock_workqueue);
2223 glock_hash_walk(clear_glock, sdp);
2224 flush_workqueue(glock_workqueue);
2225 wait_event_timeout(sdp->sd_kill_wait,
2226 atomic_read(&sdp->sd_glock_disposal) == 0,
2227 HZ * 600);
2228 glock_hash_walk(dump_glock_func, sdp);
2229}
2230
2231static const char *state2str(unsigned state)
2232{
2233 switch(state) {
2234 case LM_ST_UNLOCKED:
2235 return "UN";
2236 case LM_ST_SHARED:
2237 return "SH";
2238 case LM_ST_DEFERRED:
2239 return "DF";
2240 case LM_ST_EXCLUSIVE:
2241 return "EX";
2242 }
2243 return "??";
2244}
2245
2246static const char *hflags2str(char *buf, u16 flags, unsigned long iflags)
2247{
2248 char *p = buf;
2249 if (flags & LM_FLAG_TRY)
2250 *p++ = 't';
2251 if (flags & LM_FLAG_TRY_1CB)
2252 *p++ = 'T';
2253 if (flags & LM_FLAG_NOEXP)
2254 *p++ = 'e';
2255 if (flags & LM_FLAG_ANY)
2256 *p++ = 'A';
2257 if (flags & LM_FLAG_NODE_SCOPE)
2258 *p++ = 'n';
2259 if (flags & GL_ASYNC)
2260 *p++ = 'a';
2261 if (flags & GL_EXACT)
2262 *p++ = 'E';
2263 if (flags & GL_NOCACHE)
2264 *p++ = 'c';
2265 if (test_bit(HIF_HOLDER, &iflags))
2266 *p++ = 'H';
2267 if (test_bit(HIF_WAIT, &iflags))
2268 *p++ = 'W';
2269 if (flags & GL_SKIP)
2270 *p++ = 's';
2271 *p = 0;
2272 return buf;
2273}
2274
2275/**
2276 * dump_holder - print information about a glock holder
2277 * @seq: the seq_file struct
2278 * @gh: the glock holder
2279 * @fs_id_buf: pointer to file system id (if requested)
2280 *
2281 */
2282
2283static void dump_holder(struct seq_file *seq, const struct gfs2_holder *gh,
2284 const char *fs_id_buf)
2285{
2286 const char *comm = "(none)";
2287 pid_t owner_pid = 0;
2288 char flags_buf[32];
2289
2290 rcu_read_lock();
2291 if (pid_is_meaningful(gh)) {
2292 struct task_struct *gh_owner;
2293
2294 comm = "(ended)";
2295 owner_pid = pid_nr(gh->gh_owner_pid);
2296 gh_owner = pid_task(gh->gh_owner_pid, PIDTYPE_PID);
2297 if (gh_owner)
2298 comm = gh_owner->comm;
2299 }
2300 gfs2_print_dbg(seq, "%s H: s:%s f:%s e:%d p:%ld [%s] %pS\n",
2301 fs_id_buf, state2str(gh->gh_state),
2302 hflags2str(flags_buf, gh->gh_flags, gh->gh_iflags),
2303 gh->gh_error, (long)owner_pid, comm, (void *)gh->gh_ip);
2304 rcu_read_unlock();
2305}
2306
2307static const char *gflags2str(char *buf, const struct gfs2_glock *gl)
2308{
2309 const unsigned long *gflags = &gl->gl_flags;
2310 char *p = buf;
2311
2312 if (test_bit(GLF_LOCK, gflags))
2313 *p++ = 'l';
2314 if (test_bit(GLF_DEMOTE, gflags))
2315 *p++ = 'D';
2316 if (test_bit(GLF_PENDING_DEMOTE, gflags))
2317 *p++ = 'd';
2318 if (test_bit(GLF_DEMOTE_IN_PROGRESS, gflags))
2319 *p++ = 'p';
2320 if (test_bit(GLF_DIRTY, gflags))
2321 *p++ = 'y';
2322 if (test_bit(GLF_LFLUSH, gflags))
2323 *p++ = 'f';
2324 if (test_bit(GLF_INVALIDATE_IN_PROGRESS, gflags))
2325 *p++ = 'i';
2326 if (test_bit(GLF_REPLY_PENDING, gflags))
2327 *p++ = 'r';
2328 if (test_bit(GLF_INITIAL, gflags))
2329 *p++ = 'I';
2330 if (test_bit(GLF_FROZEN, gflags))
2331 *p++ = 'F';
2332 if (!list_empty(&gl->gl_holders))
2333 *p++ = 'q';
2334 if (test_bit(GLF_LRU, gflags))
2335 *p++ = 'L';
2336 if (gl->gl_object)
2337 *p++ = 'o';
2338 if (test_bit(GLF_BLOCKING, gflags))
2339 *p++ = 'b';
2340 if (test_bit(GLF_FREEING, gflags))
2341 *p++ = 'x';
2342 if (test_bit(GLF_INSTANTIATE_NEEDED, gflags))
2343 *p++ = 'n';
2344 if (test_bit(GLF_INSTANTIATE_IN_PROG, gflags))
2345 *p++ = 'N';
2346 if (test_bit(GLF_TRY_TO_EVICT, gflags))
2347 *p++ = 'e';
2348 if (test_bit(GLF_VERIFY_EVICT, gflags))
2349 *p++ = 'E';
2350 *p = 0;
2351 return buf;
2352}
2353
2354/**
2355 * gfs2_dump_glock - print information about a glock
2356 * @seq: The seq_file struct
2357 * @gl: the glock
2358 * @fsid: If true, also dump the file system id
2359 *
2360 * The file format is as follows:
2361 * One line per object, capital letters are used to indicate objects
2362 * G = glock, I = Inode, R = rgrp, H = holder. Glocks are not indented,
2363 * other objects are indented by a single space and follow the glock to
2364 * which they are related. Fields are indicated by lower case letters
2365 * followed by a colon and the field value, except for strings which are in
2366 * [] so that its possible to see if they are composed of spaces for
2367 * example. The field's are n = number (id of the object), f = flags,
2368 * t = type, s = state, r = refcount, e = error, p = pid.
2369 *
2370 */
2371
2372void gfs2_dump_glock(struct seq_file *seq, struct gfs2_glock *gl, bool fsid)
2373{
2374 const struct gfs2_glock_operations *glops = gl->gl_ops;
2375 unsigned long long dtime;
2376 const struct gfs2_holder *gh;
2377 char gflags_buf[32];
2378 struct gfs2_sbd *sdp = gl->gl_name.ln_sbd;
2379 char fs_id_buf[sizeof(sdp->sd_fsname) + 7];
2380 unsigned long nrpages = 0;
2381
2382 if (gl->gl_ops->go_flags & GLOF_ASPACE) {
2383 struct address_space *mapping = gfs2_glock2aspace(gl);
2384
2385 nrpages = mapping->nrpages;
2386 }
2387 memset(fs_id_buf, 0, sizeof(fs_id_buf));
2388 if (fsid && sdp) /* safety precaution */
2389 sprintf(fs_id_buf, "fsid=%s: ", sdp->sd_fsname);
2390 dtime = jiffies - gl->gl_demote_time;
2391 dtime *= 1000000/HZ; /* demote time in uSec */
2392 if (!test_bit(GLF_DEMOTE, &gl->gl_flags))
2393 dtime = 0;
2394 gfs2_print_dbg(seq, "%sG: s:%s n:%u/%llx f:%s t:%s d:%s/%llu a:%d "
2395 "v:%d r:%d m:%ld p:%lu\n",
2396 fs_id_buf, state2str(gl->gl_state),
2397 gl->gl_name.ln_type,
2398 (unsigned long long)gl->gl_name.ln_number,
2399 gflags2str(gflags_buf, gl),
2400 state2str(gl->gl_target),
2401 state2str(gl->gl_demote_state), dtime,
2402 atomic_read(&gl->gl_ail_count),
2403 atomic_read(&gl->gl_revokes),
2404 (int)gl->gl_lockref.count, gl->gl_hold_time, nrpages);
2405
2406 list_for_each_entry(gh, &gl->gl_holders, gh_list)
2407 dump_holder(seq, gh, fs_id_buf);
2408
2409 if (gl->gl_state != LM_ST_UNLOCKED && glops->go_dump)
2410 glops->go_dump(seq, gl, fs_id_buf);
2411}
2412
2413static int gfs2_glstats_seq_show(struct seq_file *seq, void *iter_ptr)
2414{
2415 struct gfs2_glock *gl = iter_ptr;
2416
2417 seq_printf(seq, "G: n:%u/%llx rtt:%llu/%llu rttb:%llu/%llu irt:%llu/%llu dcnt: %llu qcnt: %llu\n",
2418 gl->gl_name.ln_type,
2419 (unsigned long long)gl->gl_name.ln_number,
2420 (unsigned long long)gl->gl_stats.stats[GFS2_LKS_SRTT],
2421 (unsigned long long)gl->gl_stats.stats[GFS2_LKS_SRTTVAR],
2422 (unsigned long long)gl->gl_stats.stats[GFS2_LKS_SRTTB],
2423 (unsigned long long)gl->gl_stats.stats[GFS2_LKS_SRTTVARB],
2424 (unsigned long long)gl->gl_stats.stats[GFS2_LKS_SIRT],
2425 (unsigned long long)gl->gl_stats.stats[GFS2_LKS_SIRTVAR],
2426 (unsigned long long)gl->gl_stats.stats[GFS2_LKS_DCOUNT],
2427 (unsigned long long)gl->gl_stats.stats[GFS2_LKS_QCOUNT]);
2428 return 0;
2429}
2430
2431static const char *gfs2_gltype[] = {
2432 "type",
2433 "reserved",
2434 "nondisk",
2435 "inode",
2436 "rgrp",
2437 "meta",
2438 "iopen",
2439 "flock",
2440 "plock",
2441 "quota",
2442 "journal",
2443};
2444
2445static const char *gfs2_stype[] = {
2446 [GFS2_LKS_SRTT] = "srtt",
2447 [GFS2_LKS_SRTTVAR] = "srttvar",
2448 [GFS2_LKS_SRTTB] = "srttb",
2449 [GFS2_LKS_SRTTVARB] = "srttvarb",
2450 [GFS2_LKS_SIRT] = "sirt",
2451 [GFS2_LKS_SIRTVAR] = "sirtvar",
2452 [GFS2_LKS_DCOUNT] = "dlm",
2453 [GFS2_LKS_QCOUNT] = "queue",
2454};
2455
2456#define GFS2_NR_SBSTATS (ARRAY_SIZE(gfs2_gltype) * ARRAY_SIZE(gfs2_stype))
2457
2458static int gfs2_sbstats_seq_show(struct seq_file *seq, void *iter_ptr)
2459{
2460 struct gfs2_sbd *sdp = seq->private;
2461 loff_t pos = *(loff_t *)iter_ptr;
2462 unsigned index = pos >> 3;
2463 unsigned subindex = pos & 0x07;
2464 int i;
2465
2466 if (index == 0 && subindex != 0)
2467 return 0;
2468
2469 seq_printf(seq, "%-10s %8s:", gfs2_gltype[index],
2470 (index == 0) ? "cpu": gfs2_stype[subindex]);
2471
2472 for_each_possible_cpu(i) {
2473 const struct gfs2_pcpu_lkstats *lkstats = per_cpu_ptr(sdp->sd_lkstats, i);
2474
2475 if (index == 0)
2476 seq_printf(seq, " %15u", i);
2477 else
2478 seq_printf(seq, " %15llu", (unsigned long long)lkstats->
2479 lkstats[index - 1].stats[subindex]);
2480 }
2481 seq_putc(seq, '\n');
2482 return 0;
2483}
2484
2485int __init gfs2_glock_init(void)
2486{
2487 int i, ret;
2488
2489 ret = rhashtable_init(&gl_hash_table, &ht_parms);
2490 if (ret < 0)
2491 return ret;
2492
2493 glock_workqueue = alloc_workqueue("glock_workqueue", WQ_MEM_RECLAIM |
2494 WQ_HIGHPRI | WQ_FREEZABLE, 0);
2495 if (!glock_workqueue) {
2496 rhashtable_destroy(&gl_hash_table);
2497 return -ENOMEM;
2498 }
2499
2500 glock_shrinker = shrinker_alloc(0, "gfs2-glock");
2501 if (!glock_shrinker) {
2502 destroy_workqueue(glock_workqueue);
2503 rhashtable_destroy(&gl_hash_table);
2504 return -ENOMEM;
2505 }
2506
2507 glock_shrinker->count_objects = gfs2_glock_shrink_count;
2508 glock_shrinker->scan_objects = gfs2_glock_shrink_scan;
2509
2510 shrinker_register(glock_shrinker);
2511
2512 for (i = 0; i < GLOCK_WAIT_TABLE_SIZE; i++)
2513 init_waitqueue_head(glock_wait_table + i);
2514
2515 return 0;
2516}
2517
2518void gfs2_glock_exit(void)
2519{
2520 shrinker_free(glock_shrinker);
2521 rhashtable_destroy(&gl_hash_table);
2522 destroy_workqueue(glock_workqueue);
2523}
2524
2525static void gfs2_glock_iter_next(struct gfs2_glock_iter *gi, loff_t n)
2526{
2527 struct gfs2_glock *gl = gi->gl;
2528
2529 if (gl) {
2530 if (n == 0)
2531 return;
2532 if (!lockref_put_not_zero(&gl->gl_lockref))
2533 gfs2_glock_queue_put(gl);
2534 }
2535 for (;;) {
2536 gl = rhashtable_walk_next(&gi->hti);
2537 if (IS_ERR_OR_NULL(gl)) {
2538 if (gl == ERR_PTR(-EAGAIN)) {
2539 n = 1;
2540 continue;
2541 }
2542 gl = NULL;
2543 break;
2544 }
2545 if (gl->gl_name.ln_sbd != gi->sdp)
2546 continue;
2547 if (n <= 1) {
2548 if (!lockref_get_not_dead(&gl->gl_lockref))
2549 continue;
2550 break;
2551 } else {
2552 if (__lockref_is_dead(&gl->gl_lockref))
2553 continue;
2554 n--;
2555 }
2556 }
2557 gi->gl = gl;
2558}
2559
2560static void *gfs2_glock_seq_start(struct seq_file *seq, loff_t *pos)
2561 __acquires(RCU)
2562{
2563 struct gfs2_glock_iter *gi = seq->private;
2564 loff_t n;
2565
2566 /*
2567 * We can either stay where we are, skip to the next hash table
2568 * entry, or start from the beginning.
2569 */
2570 if (*pos < gi->last_pos) {
2571 rhashtable_walk_exit(&gi->hti);
2572 rhashtable_walk_enter(&gl_hash_table, &gi->hti);
2573 n = *pos + 1;
2574 } else {
2575 n = *pos - gi->last_pos;
2576 }
2577
2578 rhashtable_walk_start(&gi->hti);
2579
2580 gfs2_glock_iter_next(gi, n);
2581 gi->last_pos = *pos;
2582 return gi->gl;
2583}
2584
2585static void *gfs2_glock_seq_next(struct seq_file *seq, void *iter_ptr,
2586 loff_t *pos)
2587{
2588 struct gfs2_glock_iter *gi = seq->private;
2589
2590 (*pos)++;
2591 gi->last_pos = *pos;
2592 gfs2_glock_iter_next(gi, 1);
2593 return gi->gl;
2594}
2595
2596static void gfs2_glock_seq_stop(struct seq_file *seq, void *iter_ptr)
2597 __releases(RCU)
2598{
2599 struct gfs2_glock_iter *gi = seq->private;
2600
2601 rhashtable_walk_stop(&gi->hti);
2602}
2603
2604static int gfs2_glock_seq_show(struct seq_file *seq, void *iter_ptr)
2605{
2606 dump_glock(seq, iter_ptr, false);
2607 return 0;
2608}
2609
2610static void *gfs2_sbstats_seq_start(struct seq_file *seq, loff_t *pos)
2611{
2612 preempt_disable();
2613 if (*pos >= GFS2_NR_SBSTATS)
2614 return NULL;
2615 return pos;
2616}
2617
2618static void *gfs2_sbstats_seq_next(struct seq_file *seq, void *iter_ptr,
2619 loff_t *pos)
2620{
2621 (*pos)++;
2622 if (*pos >= GFS2_NR_SBSTATS)
2623 return NULL;
2624 return pos;
2625}
2626
2627static void gfs2_sbstats_seq_stop(struct seq_file *seq, void *iter_ptr)
2628{
2629 preempt_enable();
2630}
2631
2632static const struct seq_operations gfs2_glock_seq_ops = {
2633 .start = gfs2_glock_seq_start,
2634 .next = gfs2_glock_seq_next,
2635 .stop = gfs2_glock_seq_stop,
2636 .show = gfs2_glock_seq_show,
2637};
2638
2639static const struct seq_operations gfs2_glstats_seq_ops = {
2640 .start = gfs2_glock_seq_start,
2641 .next = gfs2_glock_seq_next,
2642 .stop = gfs2_glock_seq_stop,
2643 .show = gfs2_glstats_seq_show,
2644};
2645
2646static const struct seq_operations gfs2_sbstats_sops = {
2647 .start = gfs2_sbstats_seq_start,
2648 .next = gfs2_sbstats_seq_next,
2649 .stop = gfs2_sbstats_seq_stop,
2650 .show = gfs2_sbstats_seq_show,
2651};
2652
2653#define GFS2_SEQ_GOODSIZE min(PAGE_SIZE << PAGE_ALLOC_COSTLY_ORDER, 65536UL)
2654
2655static int __gfs2_glocks_open(struct inode *inode, struct file *file,
2656 const struct seq_operations *ops)
2657{
2658 int ret = seq_open_private(file, ops, sizeof(struct gfs2_glock_iter));
2659 if (ret == 0) {
2660 struct seq_file *seq = file->private_data;
2661 struct gfs2_glock_iter *gi = seq->private;
2662
2663 gi->sdp = inode->i_private;
2664 seq->buf = kmalloc(GFS2_SEQ_GOODSIZE, GFP_KERNEL | __GFP_NOWARN);
2665 if (seq->buf)
2666 seq->size = GFS2_SEQ_GOODSIZE;
2667 /*
2668 * Initially, we are "before" the first hash table entry; the
2669 * first call to rhashtable_walk_next gets us the first entry.
2670 */
2671 gi->last_pos = -1;
2672 gi->gl = NULL;
2673 rhashtable_walk_enter(&gl_hash_table, &gi->hti);
2674 }
2675 return ret;
2676}
2677
2678static int gfs2_glocks_open(struct inode *inode, struct file *file)
2679{
2680 return __gfs2_glocks_open(inode, file, &gfs2_glock_seq_ops);
2681}
2682
2683static int gfs2_glocks_release(struct inode *inode, struct file *file)
2684{
2685 struct seq_file *seq = file->private_data;
2686 struct gfs2_glock_iter *gi = seq->private;
2687
2688 if (gi->gl)
2689 gfs2_glock_put(gi->gl);
2690 rhashtable_walk_exit(&gi->hti);
2691 return seq_release_private(inode, file);
2692}
2693
2694static int gfs2_glstats_open(struct inode *inode, struct file *file)
2695{
2696 return __gfs2_glocks_open(inode, file, &gfs2_glstats_seq_ops);
2697}
2698
2699static const struct file_operations gfs2_glocks_fops = {
2700 .owner = THIS_MODULE,
2701 .open = gfs2_glocks_open,
2702 .read = seq_read,
2703 .llseek = seq_lseek,
2704 .release = gfs2_glocks_release,
2705};
2706
2707static const struct file_operations gfs2_glstats_fops = {
2708 .owner = THIS_MODULE,
2709 .open = gfs2_glstats_open,
2710 .read = seq_read,
2711 .llseek = seq_lseek,
2712 .release = gfs2_glocks_release,
2713};
2714
2715struct gfs2_glockfd_iter {
2716 struct super_block *sb;
2717 unsigned int tgid;
2718 struct task_struct *task;
2719 unsigned int fd;
2720 struct file *file;
2721};
2722
2723static struct task_struct *gfs2_glockfd_next_task(struct gfs2_glockfd_iter *i)
2724{
2725 struct pid_namespace *ns = task_active_pid_ns(current);
2726 struct pid *pid;
2727
2728 if (i->task)
2729 put_task_struct(i->task);
2730
2731 rcu_read_lock();
2732retry:
2733 i->task = NULL;
2734 pid = find_ge_pid(i->tgid, ns);
2735 if (pid) {
2736 i->tgid = pid_nr_ns(pid, ns);
2737 i->task = pid_task(pid, PIDTYPE_TGID);
2738 if (!i->task) {
2739 i->tgid++;
2740 goto retry;
2741 }
2742 get_task_struct(i->task);
2743 }
2744 rcu_read_unlock();
2745 return i->task;
2746}
2747
2748static struct file *gfs2_glockfd_next_file(struct gfs2_glockfd_iter *i)
2749{
2750 if (i->file) {
2751 fput(i->file);
2752 i->file = NULL;
2753 }
2754
2755 rcu_read_lock();
2756 for(;; i->fd++) {
2757 struct inode *inode;
2758
2759 i->file = task_lookup_next_fdget_rcu(i->task, &i->fd);
2760 if (!i->file) {
2761 i->fd = 0;
2762 break;
2763 }
2764
2765 inode = file_inode(i->file);
2766 if (inode->i_sb == i->sb)
2767 break;
2768
2769 rcu_read_unlock();
2770 fput(i->file);
2771 rcu_read_lock();
2772 }
2773 rcu_read_unlock();
2774 return i->file;
2775}
2776
2777static void *gfs2_glockfd_seq_start(struct seq_file *seq, loff_t *pos)
2778{
2779 struct gfs2_glockfd_iter *i = seq->private;
2780
2781 if (*pos)
2782 return NULL;
2783 while (gfs2_glockfd_next_task(i)) {
2784 if (gfs2_glockfd_next_file(i))
2785 return i;
2786 i->tgid++;
2787 }
2788 return NULL;
2789}
2790
2791static void *gfs2_glockfd_seq_next(struct seq_file *seq, void *iter_ptr,
2792 loff_t *pos)
2793{
2794 struct gfs2_glockfd_iter *i = seq->private;
2795
2796 (*pos)++;
2797 i->fd++;
2798 do {
2799 if (gfs2_glockfd_next_file(i))
2800 return i;
2801 i->tgid++;
2802 } while (gfs2_glockfd_next_task(i));
2803 return NULL;
2804}
2805
2806static void gfs2_glockfd_seq_stop(struct seq_file *seq, void *iter_ptr)
2807{
2808 struct gfs2_glockfd_iter *i = seq->private;
2809
2810 if (i->file)
2811 fput(i->file);
2812 if (i->task)
2813 put_task_struct(i->task);
2814}
2815
2816static void gfs2_glockfd_seq_show_flock(struct seq_file *seq,
2817 struct gfs2_glockfd_iter *i)
2818{
2819 struct gfs2_file *fp = i->file->private_data;
2820 struct gfs2_holder *fl_gh = &fp->f_fl_gh;
2821 struct lm_lockname gl_name = { .ln_type = LM_TYPE_RESERVED };
2822
2823 if (!READ_ONCE(fl_gh->gh_gl))
2824 return;
2825
2826 spin_lock(&i->file->f_lock);
2827 if (gfs2_holder_initialized(fl_gh))
2828 gl_name = fl_gh->gh_gl->gl_name;
2829 spin_unlock(&i->file->f_lock);
2830
2831 if (gl_name.ln_type != LM_TYPE_RESERVED) {
2832 seq_printf(seq, "%d %u %u/%llx\n",
2833 i->tgid, i->fd, gl_name.ln_type,
2834 (unsigned long long)gl_name.ln_number);
2835 }
2836}
2837
2838static int gfs2_glockfd_seq_show(struct seq_file *seq, void *iter_ptr)
2839{
2840 struct gfs2_glockfd_iter *i = seq->private;
2841 struct inode *inode = file_inode(i->file);
2842 struct gfs2_glock *gl;
2843
2844 inode_lock_shared(inode);
2845 gl = GFS2_I(inode)->i_iopen_gh.gh_gl;
2846 if (gl) {
2847 seq_printf(seq, "%d %u %u/%llx\n",
2848 i->tgid, i->fd, gl->gl_name.ln_type,
2849 (unsigned long long)gl->gl_name.ln_number);
2850 }
2851 gfs2_glockfd_seq_show_flock(seq, i);
2852 inode_unlock_shared(inode);
2853 return 0;
2854}
2855
2856static const struct seq_operations gfs2_glockfd_seq_ops = {
2857 .start = gfs2_glockfd_seq_start,
2858 .next = gfs2_glockfd_seq_next,
2859 .stop = gfs2_glockfd_seq_stop,
2860 .show = gfs2_glockfd_seq_show,
2861};
2862
2863static int gfs2_glockfd_open(struct inode *inode, struct file *file)
2864{
2865 struct gfs2_glockfd_iter *i;
2866 struct gfs2_sbd *sdp = inode->i_private;
2867
2868 i = __seq_open_private(file, &gfs2_glockfd_seq_ops,
2869 sizeof(struct gfs2_glockfd_iter));
2870 if (!i)
2871 return -ENOMEM;
2872 i->sb = sdp->sd_vfs;
2873 return 0;
2874}
2875
2876static const struct file_operations gfs2_glockfd_fops = {
2877 .owner = THIS_MODULE,
2878 .open = gfs2_glockfd_open,
2879 .read = seq_read,
2880 .llseek = seq_lseek,
2881 .release = seq_release_private,
2882};
2883
2884DEFINE_SEQ_ATTRIBUTE(gfs2_sbstats);
2885
2886void gfs2_create_debugfs_file(struct gfs2_sbd *sdp)
2887{
2888 sdp->debugfs_dir = debugfs_create_dir(sdp->sd_table_name, gfs2_root);
2889
2890 debugfs_create_file("glocks", S_IFREG | S_IRUGO, sdp->debugfs_dir, sdp,
2891 &gfs2_glocks_fops);
2892
2893 debugfs_create_file("glockfd", S_IFREG | S_IRUGO, sdp->debugfs_dir, sdp,
2894 &gfs2_glockfd_fops);
2895
2896 debugfs_create_file("glstats", S_IFREG | S_IRUGO, sdp->debugfs_dir, sdp,
2897 &gfs2_glstats_fops);
2898
2899 debugfs_create_file("sbstats", S_IFREG | S_IRUGO, sdp->debugfs_dir, sdp,
2900 &gfs2_sbstats_fops);
2901}
2902
2903void gfs2_delete_debugfs_file(struct gfs2_sbd *sdp)
2904{
2905 debugfs_remove_recursive(sdp->debugfs_dir);
2906 sdp->debugfs_dir = NULL;
2907}
2908
2909void gfs2_register_debugfs(void)
2910{
2911 gfs2_root = debugfs_create_dir("gfs2", NULL);
2912}
2913
2914void gfs2_unregister_debugfs(void)
2915{
2916 debugfs_remove(gfs2_root);
2917 gfs2_root = NULL;
2918}