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 <linux/rwsem.h>
23 #include <asm/uaccess.h>
24 #include <linux/seq_file.h>
25 #include <linux/debugfs.h>
26 #include <linux/kthread.h>
27 #include <linux/freezer.h>
28 #include <linux/workqueue.h>
29 #include <linux/jiffies.h>
30
31 #include "gfs2.h"
32 #include "incore.h"
33 #include "glock.h"
34 #include "glops.h"
35 #include "inode.h"
36 #include "lops.h"
37 #include "meta_io.h"
38 #include "quota.h"
39 #include "super.h"
40 #include "util.h"
41 #include "bmap.h"
42 #define CREATE_TRACE_POINTS
43 #include "trace_gfs2.h"
44
45 struct gfs2_gl_hash_bucket {
46 struct hlist_head hb_list;
47 };
48
49 struct gfs2_glock_iter {
50 int hash; /* hash bucket index */
51 struct gfs2_sbd *sdp; /* incore superblock */
52 struct gfs2_glock *gl; /* current glock struct */
53 char string[512]; /* scratch space */
54 };
55
56 typedef void (*glock_examiner) (struct gfs2_glock * gl);
57
58 static int gfs2_dump_lockstate(struct gfs2_sbd *sdp);
59 static int __dump_glock(struct seq_file *seq, const struct gfs2_glock *gl);
60 #define GLOCK_BUG_ON(gl,x) do { if (unlikely(x)) { __dump_glock(NULL, gl); BUG(); } } while(0)
61 static void do_xmote(struct gfs2_glock *gl, struct gfs2_holder *gh, unsigned int target);
62
63 static DECLARE_RWSEM(gfs2_umount_flush_sem);
64 static struct dentry *gfs2_root;
65 static struct workqueue_struct *glock_workqueue;
66 struct workqueue_struct *gfs2_delete_workqueue;
67 static LIST_HEAD(lru_list);
68 static atomic_t lru_count = ATOMIC_INIT(0);
69 static DEFINE_SPINLOCK(lru_lock);
70
71 #define GFS2_GL_HASH_SHIFT 15
72 #define GFS2_GL_HASH_SIZE (1 << GFS2_GL_HASH_SHIFT)
73 #define GFS2_GL_HASH_MASK (GFS2_GL_HASH_SIZE - 1)
74
75 static struct gfs2_gl_hash_bucket gl_hash_table[GFS2_GL_HASH_SIZE];
76 static struct dentry *gfs2_root;
77
78 /*
79 * Despite what you might think, the numbers below are not arbitrary :-)
80 * They are taken from the ipv4 routing hash code, which is well tested
81 * and thus should be nearly optimal. Later on we might tweek the numbers
82 * but for now this should be fine.
83 *
84 * The reason for putting the locks in a separate array from the list heads
85 * is that we can have fewer locks than list heads and save memory. We use
86 * the same hash function for both, but with a different hash mask.
87 */
88 #if defined(CONFIG_SMP) || defined(CONFIG_DEBUG_SPINLOCK) || \
89 defined(CONFIG_PROVE_LOCKING)
90
91 #ifdef CONFIG_LOCKDEP
92 # define GL_HASH_LOCK_SZ 256
93 #else
94 # if NR_CPUS >= 32
95 # define GL_HASH_LOCK_SZ 4096
96 # elif NR_CPUS >= 16
97 # define GL_HASH_LOCK_SZ 2048
98 # elif NR_CPUS >= 8
99 # define GL_HASH_LOCK_SZ 1024
100 # elif NR_CPUS >= 4
101 # define GL_HASH_LOCK_SZ 512
102 # else
103 # define GL_HASH_LOCK_SZ 256
104 # endif
105 #endif
106
107 /* We never want more locks than chains */
108 #if GFS2_GL_HASH_SIZE < GL_HASH_LOCK_SZ
109 # undef GL_HASH_LOCK_SZ
110 # define GL_HASH_LOCK_SZ GFS2_GL_HASH_SIZE
111 #endif
112
113 static rwlock_t gl_hash_locks[GL_HASH_LOCK_SZ];
114
115 static inline rwlock_t *gl_lock_addr(unsigned int x)
116 {
117 return &gl_hash_locks[x & (GL_HASH_LOCK_SZ-1)];
118 }
119 #else /* not SMP, so no spinlocks required */
120 static inline rwlock_t *gl_lock_addr(unsigned int x)
121 {
122 return NULL;
123 }
124 #endif
125
126 /**
127 * gl_hash() - Turn glock number into hash bucket number
128 * @lock: The glock number
129 *
130 * Returns: The number of the corresponding hash bucket
131 */
132
133 static unsigned int gl_hash(const struct gfs2_sbd *sdp,
134 const struct lm_lockname *name)
135 {
136 unsigned int h;
137
138 h = jhash(&name->ln_number, sizeof(u64), 0);
139 h = jhash(&name->ln_type, sizeof(unsigned int), h);
140 h = jhash(&sdp, sizeof(struct gfs2_sbd *), h);
141 h &= GFS2_GL_HASH_MASK;
142
143 return h;
144 }
145
146 /**
147 * glock_free() - Perform a few checks and then release struct gfs2_glock
148 * @gl: The glock to release
149 *
150 * Also calls lock module to release its internal structure for this glock.
151 *
152 */
153
154 static void glock_free(struct gfs2_glock *gl)
155 {
156 struct gfs2_sbd *sdp = gl->gl_sbd;
157 struct inode *aspace = gl->gl_aspace;
158
159 if (aspace)
160 gfs2_aspace_put(aspace);
161 trace_gfs2_glock_put(gl);
162 sdp->sd_lockstruct.ls_ops->lm_put_lock(gfs2_glock_cachep, gl);
163 }
164
165 /**
166 * gfs2_glock_hold() - increment reference count on glock
167 * @gl: The glock to hold
168 *
169 */
170
171 void gfs2_glock_hold(struct gfs2_glock *gl)
172 {
173 GLOCK_BUG_ON(gl, atomic_read(&gl->gl_ref) == 0);
174 atomic_inc(&gl->gl_ref);
175 }
176
177 /**
178 * demote_ok - Check to see if it's ok to unlock a glock
179 * @gl: the glock
180 *
181 * Returns: 1 if it's ok
182 */
183
184 static int demote_ok(const struct gfs2_glock *gl)
185 {
186 const struct gfs2_glock_operations *glops = gl->gl_ops;
187
188 if (gl->gl_state == LM_ST_UNLOCKED)
189 return 0;
190 if (!list_empty(&gl->gl_holders))
191 return 0;
192 if (glops->go_demote_ok)
193 return glops->go_demote_ok(gl);
194 return 1;
195 }
196
197 /**
198 * gfs2_glock_schedule_for_reclaim - Add a glock to the reclaim list
199 * @gl: the glock
200 *
201 */
202
203 static void gfs2_glock_schedule_for_reclaim(struct gfs2_glock *gl)
204 {
205 int may_reclaim;
206 may_reclaim = (demote_ok(gl) &&
207 (atomic_read(&gl->gl_ref) == 1 ||
208 (gl->gl_name.ln_type == LM_TYPE_INODE &&
209 atomic_read(&gl->gl_ref) <= 2)));
210 spin_lock(&lru_lock);
211 if (list_empty(&gl->gl_lru) && may_reclaim) {
212 list_add_tail(&gl->gl_lru, &lru_list);
213 atomic_inc(&lru_count);
214 }
215 spin_unlock(&lru_lock);
216 }
217
218 /**
219 * gfs2_glock_put_nolock() - Decrement reference count on glock
220 * @gl: The glock to put
221 *
222 * This function should only be used if the caller has its own reference
223 * to the glock, in addition to the one it is dropping.
224 */
225
226 void gfs2_glock_put_nolock(struct gfs2_glock *gl)
227 {
228 if (atomic_dec_and_test(&gl->gl_ref))
229 GLOCK_BUG_ON(gl, 1);
230 gfs2_glock_schedule_for_reclaim(gl);
231 }
232
233 /**
234 * gfs2_glock_put() - Decrement reference count on glock
235 * @gl: The glock to put
236 *
237 */
238
239 int gfs2_glock_put(struct gfs2_glock *gl)
240 {
241 int rv = 0;
242
243 write_lock(gl_lock_addr(gl->gl_hash));
244 if (atomic_dec_and_test(&gl->gl_ref)) {
245 hlist_del(&gl->gl_list);
246 write_unlock(gl_lock_addr(gl->gl_hash));
247 spin_lock(&lru_lock);
248 if (!list_empty(&gl->gl_lru)) {
249 list_del_init(&gl->gl_lru);
250 atomic_dec(&lru_count);
251 }
252 spin_unlock(&lru_lock);
253 GLOCK_BUG_ON(gl, !list_empty(&gl->gl_holders));
254 glock_free(gl);
255 rv = 1;
256 goto out;
257 }
258 spin_lock(&gl->gl_spin);
259 gfs2_glock_schedule_for_reclaim(gl);
260 spin_unlock(&gl->gl_spin);
261 write_unlock(gl_lock_addr(gl->gl_hash));
262 out:
263 return rv;
264 }
265
266 /**
267 * search_bucket() - Find struct gfs2_glock by lock number
268 * @bucket: the bucket to search
269 * @name: The lock name
270 *
271 * Returns: NULL, or the struct gfs2_glock with the requested number
272 */
273
274 static struct gfs2_glock *search_bucket(unsigned int hash,
275 const struct gfs2_sbd *sdp,
276 const struct lm_lockname *name)
277 {
278 struct gfs2_glock *gl;
279 struct hlist_node *h;
280
281 hlist_for_each_entry(gl, h, &gl_hash_table[hash].hb_list, gl_list) {
282 if (!lm_name_equal(&gl->gl_name, name))
283 continue;
284 if (gl->gl_sbd != sdp)
285 continue;
286
287 atomic_inc(&gl->gl_ref);
288
289 return gl;
290 }
291
292 return NULL;
293 }
294
295 /**
296 * may_grant - check if its ok to grant a new lock
297 * @gl: The glock
298 * @gh: The lock request which we wish to grant
299 *
300 * Returns: true if its ok to grant the lock
301 */
302
303 static inline int may_grant(const struct gfs2_glock *gl, const struct gfs2_holder *gh)
304 {
305 const struct gfs2_holder *gh_head = list_entry(gl->gl_holders.next, const struct gfs2_holder, gh_list);
306 if ((gh->gh_state == LM_ST_EXCLUSIVE ||
307 gh_head->gh_state == LM_ST_EXCLUSIVE) && gh != gh_head)
308 return 0;
309 if (gl->gl_state == gh->gh_state)
310 return 1;
311 if (gh->gh_flags & GL_EXACT)
312 return 0;
313 if (gl->gl_state == LM_ST_EXCLUSIVE) {
314 if (gh->gh_state == LM_ST_SHARED && gh_head->gh_state == LM_ST_SHARED)
315 return 1;
316 if (gh->gh_state == LM_ST_DEFERRED && gh_head->gh_state == LM_ST_DEFERRED)
317 return 1;
318 }
319 if (gl->gl_state != LM_ST_UNLOCKED && (gh->gh_flags & LM_FLAG_ANY))
320 return 1;
321 return 0;
322 }
323
324 static void gfs2_holder_wake(struct gfs2_holder *gh)
325 {
326 clear_bit(HIF_WAIT, &gh->gh_iflags);
327 smp_mb__after_clear_bit();
328 wake_up_bit(&gh->gh_iflags, HIF_WAIT);
329 }
330
331 /**
332 * do_promote - promote as many requests as possible on the current queue
333 * @gl: The glock
334 *
335 * Returns: 1 if there is a blocked holder at the head of the list, or 2
336 * if a type specific operation is underway.
337 */
338
339 static int do_promote(struct gfs2_glock *gl)
340 __releases(&gl->gl_spin)
341 __acquires(&gl->gl_spin)
342 {
343 const struct gfs2_glock_operations *glops = gl->gl_ops;
344 struct gfs2_holder *gh, *tmp;
345 int ret;
346
347 restart:
348 list_for_each_entry_safe(gh, tmp, &gl->gl_holders, gh_list) {
349 if (test_bit(HIF_HOLDER, &gh->gh_iflags))
350 continue;
351 if (may_grant(gl, gh)) {
352 if (gh->gh_list.prev == &gl->gl_holders &&
353 glops->go_lock) {
354 spin_unlock(&gl->gl_spin);
355 /* FIXME: eliminate this eventually */
356 ret = glops->go_lock(gh);
357 spin_lock(&gl->gl_spin);
358 if (ret) {
359 if (ret == 1)
360 return 2;
361 gh->gh_error = ret;
362 list_del_init(&gh->gh_list);
363 trace_gfs2_glock_queue(gh, 0);
364 gfs2_holder_wake(gh);
365 goto restart;
366 }
367 set_bit(HIF_HOLDER, &gh->gh_iflags);
368 trace_gfs2_promote(gh, 1);
369 gfs2_holder_wake(gh);
370 goto restart;
371 }
372 set_bit(HIF_HOLDER, &gh->gh_iflags);
373 trace_gfs2_promote(gh, 0);
374 gfs2_holder_wake(gh);
375 continue;
376 }
377 if (gh->gh_list.prev == &gl->gl_holders)
378 return 1;
379 break;
380 }
381 return 0;
382 }
383
384 /**
385 * do_error - Something unexpected has happened during a lock request
386 *
387 */
388
389 static inline void do_error(struct gfs2_glock *gl, const int ret)
390 {
391 struct gfs2_holder *gh, *tmp;
392
393 list_for_each_entry_safe(gh, tmp, &gl->gl_holders, gh_list) {
394 if (test_bit(HIF_HOLDER, &gh->gh_iflags))
395 continue;
396 if (ret & LM_OUT_ERROR)
397 gh->gh_error = -EIO;
398 else if (gh->gh_flags & (LM_FLAG_TRY | LM_FLAG_TRY_1CB))
399 gh->gh_error = GLR_TRYFAILED;
400 else
401 continue;
402 list_del_init(&gh->gh_list);
403 trace_gfs2_glock_queue(gh, 0);
404 gfs2_holder_wake(gh);
405 }
406 }
407
408 /**
409 * find_first_waiter - find the first gh that's waiting for the glock
410 * @gl: the glock
411 */
412
413 static inline struct gfs2_holder *find_first_waiter(const struct gfs2_glock *gl)
414 {
415 struct gfs2_holder *gh;
416
417 list_for_each_entry(gh, &gl->gl_holders, gh_list) {
418 if (!test_bit(HIF_HOLDER, &gh->gh_iflags))
419 return gh;
420 }
421 return NULL;
422 }
423
424 /**
425 * state_change - record that the glock is now in a different state
426 * @gl: the glock
427 * @new_state the new state
428 *
429 */
430
431 static void state_change(struct gfs2_glock *gl, unsigned int new_state)
432 {
433 int held1, held2;
434
435 held1 = (gl->gl_state != LM_ST_UNLOCKED);
436 held2 = (new_state != LM_ST_UNLOCKED);
437
438 if (held1 != held2) {
439 if (held2)
440 gfs2_glock_hold(gl);
441 else
442 gfs2_glock_put_nolock(gl);
443 }
444
445 gl->gl_state = new_state;
446 gl->gl_tchange = jiffies;
447 }
448
449 static void gfs2_demote_wake(struct gfs2_glock *gl)
450 {
451 gl->gl_demote_state = LM_ST_EXCLUSIVE;
452 clear_bit(GLF_DEMOTE, &gl->gl_flags);
453 smp_mb__after_clear_bit();
454 wake_up_bit(&gl->gl_flags, GLF_DEMOTE);
455 }
456
457 /**
458 * finish_xmote - The DLM has replied to one of our lock requests
459 * @gl: The glock
460 * @ret: The status from the DLM
461 *
462 */
463
464 static void finish_xmote(struct gfs2_glock *gl, unsigned int ret)
465 {
466 const struct gfs2_glock_operations *glops = gl->gl_ops;
467 struct gfs2_holder *gh;
468 unsigned state = ret & LM_OUT_ST_MASK;
469 int rv;
470
471 spin_lock(&gl->gl_spin);
472 trace_gfs2_glock_state_change(gl, state);
473 state_change(gl, state);
474 gh = find_first_waiter(gl);
475
476 /* Demote to UN request arrived during demote to SH or DF */
477 if (test_bit(GLF_DEMOTE_IN_PROGRESS, &gl->gl_flags) &&
478 state != LM_ST_UNLOCKED && gl->gl_demote_state == LM_ST_UNLOCKED)
479 gl->gl_target = LM_ST_UNLOCKED;
480
481 /* Check for state != intended state */
482 if (unlikely(state != gl->gl_target)) {
483 if (gh && !test_bit(GLF_DEMOTE_IN_PROGRESS, &gl->gl_flags)) {
484 /* move to back of queue and try next entry */
485 if (ret & LM_OUT_CANCELED) {
486 if ((gh->gh_flags & LM_FLAG_PRIORITY) == 0)
487 list_move_tail(&gh->gh_list, &gl->gl_holders);
488 gh = find_first_waiter(gl);
489 gl->gl_target = gh->gh_state;
490 goto retry;
491 }
492 /* Some error or failed "try lock" - report it */
493 if ((ret & LM_OUT_ERROR) ||
494 (gh->gh_flags & (LM_FLAG_TRY | LM_FLAG_TRY_1CB))) {
495 gl->gl_target = gl->gl_state;
496 do_error(gl, ret);
497 goto out;
498 }
499 }
500 switch(state) {
501 /* Unlocked due to conversion deadlock, try again */
502 case LM_ST_UNLOCKED:
503 retry:
504 do_xmote(gl, gh, gl->gl_target);
505 break;
506 /* Conversion fails, unlock and try again */
507 case LM_ST_SHARED:
508 case LM_ST_DEFERRED:
509 do_xmote(gl, gh, LM_ST_UNLOCKED);
510 break;
511 default: /* Everything else */
512 printk(KERN_ERR "GFS2: wanted %u got %u\n", gl->gl_target, state);
513 GLOCK_BUG_ON(gl, 1);
514 }
515 spin_unlock(&gl->gl_spin);
516 gfs2_glock_put(gl);
517 return;
518 }
519
520 /* Fast path - we got what we asked for */
521 if (test_and_clear_bit(GLF_DEMOTE_IN_PROGRESS, &gl->gl_flags))
522 gfs2_demote_wake(gl);
523 if (state != LM_ST_UNLOCKED) {
524 if (glops->go_xmote_bh) {
525 spin_unlock(&gl->gl_spin);
526 rv = glops->go_xmote_bh(gl, gh);
527 if (rv == -EAGAIN)
528 return;
529 spin_lock(&gl->gl_spin);
530 if (rv) {
531 do_error(gl, rv);
532 goto out;
533 }
534 }
535 rv = do_promote(gl);
536 if (rv == 2)
537 goto out_locked;
538 }
539 out:
540 clear_bit(GLF_LOCK, &gl->gl_flags);
541 out_locked:
542 spin_unlock(&gl->gl_spin);
543 gfs2_glock_put(gl);
544 }
545
546 static unsigned int gfs2_lm_lock(struct gfs2_sbd *sdp, void *lock,
547 unsigned int req_state,
548 unsigned int flags)
549 {
550 int ret = LM_OUT_ERROR;
551
552 if (!sdp->sd_lockstruct.ls_ops->lm_lock)
553 return req_state == LM_ST_UNLOCKED ? 0 : req_state;
554
555 if (likely(!test_bit(SDF_SHUTDOWN, &sdp->sd_flags)))
556 ret = sdp->sd_lockstruct.ls_ops->lm_lock(lock,
557 req_state, flags);
558 return ret;
559 }
560
561 /**
562 * do_xmote - Calls the DLM to change the state of a lock
563 * @gl: The lock state
564 * @gh: The holder (only for promotes)
565 * @target: The target lock state
566 *
567 */
568
569 static void do_xmote(struct gfs2_glock *gl, struct gfs2_holder *gh, unsigned int target)
570 __releases(&gl->gl_spin)
571 __acquires(&gl->gl_spin)
572 {
573 const struct gfs2_glock_operations *glops = gl->gl_ops;
574 struct gfs2_sbd *sdp = gl->gl_sbd;
575 unsigned int lck_flags = gh ? gh->gh_flags : 0;
576 int ret;
577
578 lck_flags &= (LM_FLAG_TRY | LM_FLAG_TRY_1CB | LM_FLAG_NOEXP |
579 LM_FLAG_PRIORITY);
580 BUG_ON(gl->gl_state == target);
581 BUG_ON(gl->gl_state == gl->gl_target);
582 if ((target == LM_ST_UNLOCKED || target == LM_ST_DEFERRED) &&
583 glops->go_inval) {
584 set_bit(GLF_INVALIDATE_IN_PROGRESS, &gl->gl_flags);
585 do_error(gl, 0); /* Fail queued try locks */
586 }
587 spin_unlock(&gl->gl_spin);
588 if (glops->go_xmote_th)
589 glops->go_xmote_th(gl);
590 if (test_bit(GLF_INVALIDATE_IN_PROGRESS, &gl->gl_flags))
591 glops->go_inval(gl, target == LM_ST_DEFERRED ? 0 : DIO_METADATA);
592 clear_bit(GLF_INVALIDATE_IN_PROGRESS, &gl->gl_flags);
593
594 gfs2_glock_hold(gl);
595 if (target != LM_ST_UNLOCKED && (gl->gl_state == LM_ST_SHARED ||
596 gl->gl_state == LM_ST_DEFERRED) &&
597 !(lck_flags & (LM_FLAG_TRY | LM_FLAG_TRY_1CB)))
598 lck_flags |= LM_FLAG_TRY_1CB;
599 ret = gfs2_lm_lock(sdp, gl, target, lck_flags);
600
601 if (!(ret & LM_OUT_ASYNC)) {
602 finish_xmote(gl, ret);
603 gfs2_glock_hold(gl);
604 if (queue_delayed_work(glock_workqueue, &gl->gl_work, 0) == 0)
605 gfs2_glock_put(gl);
606 } else {
607 GLOCK_BUG_ON(gl, ret != LM_OUT_ASYNC);
608 }
609 spin_lock(&gl->gl_spin);
610 }
611
612 /**
613 * find_first_holder - find the first "holder" gh
614 * @gl: the glock
615 */
616
617 static inline struct gfs2_holder *find_first_holder(const struct gfs2_glock *gl)
618 {
619 struct gfs2_holder *gh;
620
621 if (!list_empty(&gl->gl_holders)) {
622 gh = list_entry(gl->gl_holders.next, struct gfs2_holder, gh_list);
623 if (test_bit(HIF_HOLDER, &gh->gh_iflags))
624 return gh;
625 }
626 return NULL;
627 }
628
629 /**
630 * run_queue - do all outstanding tasks related to a glock
631 * @gl: The glock in question
632 * @nonblock: True if we must not block in run_queue
633 *
634 */
635
636 static void run_queue(struct gfs2_glock *gl, const int nonblock)
637 __releases(&gl->gl_spin)
638 __acquires(&gl->gl_spin)
639 {
640 struct gfs2_holder *gh = NULL;
641 int ret;
642
643 if (test_and_set_bit(GLF_LOCK, &gl->gl_flags))
644 return;
645
646 GLOCK_BUG_ON(gl, test_bit(GLF_DEMOTE_IN_PROGRESS, &gl->gl_flags));
647
648 if (test_bit(GLF_DEMOTE, &gl->gl_flags) &&
649 gl->gl_demote_state != gl->gl_state) {
650 if (find_first_holder(gl))
651 goto out_unlock;
652 if (nonblock)
653 goto out_sched;
654 set_bit(GLF_DEMOTE_IN_PROGRESS, &gl->gl_flags);
655 GLOCK_BUG_ON(gl, gl->gl_demote_state == LM_ST_EXCLUSIVE);
656 gl->gl_target = gl->gl_demote_state;
657 } else {
658 if (test_bit(GLF_DEMOTE, &gl->gl_flags))
659 gfs2_demote_wake(gl);
660 ret = do_promote(gl);
661 if (ret == 0)
662 goto out_unlock;
663 if (ret == 2)
664 goto out;
665 gh = find_first_waiter(gl);
666 gl->gl_target = gh->gh_state;
667 if (!(gh->gh_flags & (LM_FLAG_TRY | LM_FLAG_TRY_1CB)))
668 do_error(gl, 0); /* Fail queued try locks */
669 }
670 do_xmote(gl, gh, gl->gl_target);
671 out:
672 return;
673
674 out_sched:
675 gfs2_glock_hold(gl);
676 if (queue_delayed_work(glock_workqueue, &gl->gl_work, 0) == 0)
677 gfs2_glock_put_nolock(gl);
678 out_unlock:
679 clear_bit(GLF_LOCK, &gl->gl_flags);
680 goto out;
681 }
682
683 static void delete_work_func(struct work_struct *work)
684 {
685 struct gfs2_glock *gl = container_of(work, struct gfs2_glock, gl_delete);
686 struct gfs2_sbd *sdp = gl->gl_sbd;
687 struct gfs2_inode *ip = NULL;
688 struct inode *inode;
689 u64 no_addr = 0;
690
691 spin_lock(&gl->gl_spin);
692 ip = (struct gfs2_inode *)gl->gl_object;
693 if (ip)
694 no_addr = ip->i_no_addr;
695 spin_unlock(&gl->gl_spin);
696 if (ip) {
697 inode = gfs2_ilookup(sdp->sd_vfs, no_addr);
698 if (inode) {
699 d_prune_aliases(inode);
700 iput(inode);
701 }
702 }
703 gfs2_glock_put(gl);
704 }
705
706 static void glock_work_func(struct work_struct *work)
707 {
708 unsigned long delay = 0;
709 struct gfs2_glock *gl = container_of(work, struct gfs2_glock, gl_work.work);
710
711 if (test_and_clear_bit(GLF_REPLY_PENDING, &gl->gl_flags))
712 finish_xmote(gl, gl->gl_reply);
713 down_read(&gfs2_umount_flush_sem);
714 spin_lock(&gl->gl_spin);
715 if (test_and_clear_bit(GLF_PENDING_DEMOTE, &gl->gl_flags) &&
716 gl->gl_state != LM_ST_UNLOCKED &&
717 gl->gl_demote_state != LM_ST_EXCLUSIVE) {
718 unsigned long holdtime, now = jiffies;
719 holdtime = gl->gl_tchange + gl->gl_ops->go_min_hold_time;
720 if (time_before(now, holdtime))
721 delay = holdtime - now;
722 set_bit(delay ? GLF_PENDING_DEMOTE : GLF_DEMOTE, &gl->gl_flags);
723 }
724 run_queue(gl, 0);
725 spin_unlock(&gl->gl_spin);
726 up_read(&gfs2_umount_flush_sem);
727 if (!delay ||
728 queue_delayed_work(glock_workqueue, &gl->gl_work, delay) == 0)
729 gfs2_glock_put(gl);
730 }
731
732 /**
733 * gfs2_glock_get() - Get a glock, or create one if one doesn't exist
734 * @sdp: The GFS2 superblock
735 * @number: the lock number
736 * @glops: The glock_operations to use
737 * @create: If 0, don't create the glock if it doesn't exist
738 * @glp: the glock is returned here
739 *
740 * This does not lock a glock, just finds/creates structures for one.
741 *
742 * Returns: errno
743 */
744
745 int gfs2_glock_get(struct gfs2_sbd *sdp, u64 number,
746 const struct gfs2_glock_operations *glops, int create,
747 struct gfs2_glock **glp)
748 {
749 struct lm_lockname name = { .ln_number = number, .ln_type = glops->go_type };
750 struct gfs2_glock *gl, *tmp;
751 unsigned int hash = gl_hash(sdp, &name);
752 int error;
753
754 read_lock(gl_lock_addr(hash));
755 gl = search_bucket(hash, sdp, &name);
756 read_unlock(gl_lock_addr(hash));
757
758 *glp = gl;
759 if (gl)
760 return 0;
761 if (!create)
762 return -ENOENT;
763
764 gl = kmem_cache_alloc(gfs2_glock_cachep, GFP_KERNEL);
765 if (!gl)
766 return -ENOMEM;
767
768 gl->gl_flags = 0;
769 gl->gl_name = name;
770 atomic_set(&gl->gl_ref, 1);
771 gl->gl_state = LM_ST_UNLOCKED;
772 gl->gl_target = LM_ST_UNLOCKED;
773 gl->gl_demote_state = LM_ST_EXCLUSIVE;
774 gl->gl_hash = hash;
775 gl->gl_ops = glops;
776 snprintf(gl->gl_strname, GDLM_STRNAME_BYTES, "%8x%16llx", name.ln_type, (unsigned long long)number);
777 memset(&gl->gl_lksb, 0, sizeof(struct dlm_lksb));
778 gl->gl_lksb.sb_lvbptr = gl->gl_lvb;
779 gl->gl_tchange = jiffies;
780 gl->gl_object = NULL;
781 gl->gl_sbd = sdp;
782 gl->gl_aspace = NULL;
783 INIT_DELAYED_WORK(&gl->gl_work, glock_work_func);
784 INIT_WORK(&gl->gl_delete, delete_work_func);
785
786 /* If this glock protects actual on-disk data or metadata blocks,
787 create a VFS inode to manage the pages/buffers holding them. */
788 if (glops == &gfs2_inode_glops || glops == &gfs2_rgrp_glops) {
789 gl->gl_aspace = gfs2_aspace_get(sdp);
790 if (!gl->gl_aspace) {
791 error = -ENOMEM;
792 goto fail;
793 }
794 }
795
796 write_lock(gl_lock_addr(hash));
797 tmp = search_bucket(hash, sdp, &name);
798 if (tmp) {
799 write_unlock(gl_lock_addr(hash));
800 glock_free(gl);
801 gl = tmp;
802 } else {
803 hlist_add_head(&gl->gl_list, &gl_hash_table[hash].hb_list);
804 write_unlock(gl_lock_addr(hash));
805 }
806
807 *glp = gl;
808
809 return 0;
810
811 fail:
812 kmem_cache_free(gfs2_glock_cachep, gl);
813 return error;
814 }
815
816 /**
817 * gfs2_holder_init - initialize a struct gfs2_holder in the default way
818 * @gl: the glock
819 * @state: the state we're requesting
820 * @flags: the modifier flags
821 * @gh: the holder structure
822 *
823 */
824
825 void gfs2_holder_init(struct gfs2_glock *gl, unsigned int state, unsigned flags,
826 struct gfs2_holder *gh)
827 {
828 INIT_LIST_HEAD(&gh->gh_list);
829 gh->gh_gl = gl;
830 gh->gh_ip = (unsigned long)__builtin_return_address(0);
831 gh->gh_owner_pid = get_pid(task_pid(current));
832 gh->gh_state = state;
833 gh->gh_flags = flags;
834 gh->gh_error = 0;
835 gh->gh_iflags = 0;
836 gfs2_glock_hold(gl);
837 }
838
839 /**
840 * gfs2_holder_reinit - reinitialize a struct gfs2_holder so we can requeue it
841 * @state: the state we're requesting
842 * @flags: the modifier flags
843 * @gh: the holder structure
844 *
845 * Don't mess with the glock.
846 *
847 */
848
849 void gfs2_holder_reinit(unsigned int state, unsigned flags, struct gfs2_holder *gh)
850 {
851 gh->gh_state = state;
852 gh->gh_flags = flags;
853 gh->gh_iflags = 0;
854 gh->gh_ip = (unsigned long)__builtin_return_address(0);
855 }
856
857 /**
858 * gfs2_holder_uninit - uninitialize a holder structure (drop glock reference)
859 * @gh: the holder structure
860 *
861 */
862
863 void gfs2_holder_uninit(struct gfs2_holder *gh)
864 {
865 put_pid(gh->gh_owner_pid);
866 gfs2_glock_put(gh->gh_gl);
867 gh->gh_gl = NULL;
868 gh->gh_ip = 0;
869 }
870
871 /**
872 * gfs2_glock_holder_wait
873 * @word: unused
874 *
875 * This function and gfs2_glock_demote_wait both show up in the WCHAN
876 * field. Thus I've separated these otherwise identical functions in
877 * order to be more informative to the user.
878 */
879
880 static int gfs2_glock_holder_wait(void *word)
881 {
882 schedule();
883 return 0;
884 }
885
886 static int gfs2_glock_demote_wait(void *word)
887 {
888 schedule();
889 return 0;
890 }
891
892 static void wait_on_holder(struct gfs2_holder *gh)
893 {
894 might_sleep();
895 wait_on_bit(&gh->gh_iflags, HIF_WAIT, gfs2_glock_holder_wait, TASK_UNINTERRUPTIBLE);
896 }
897
898 static void wait_on_demote(struct gfs2_glock *gl)
899 {
900 might_sleep();
901 wait_on_bit(&gl->gl_flags, GLF_DEMOTE, gfs2_glock_demote_wait, TASK_UNINTERRUPTIBLE);
902 }
903
904 /**
905 * handle_callback - process a demote request
906 * @gl: the glock
907 * @state: the state the caller wants us to change to
908 *
909 * There are only two requests that we are going to see in actual
910 * practise: LM_ST_SHARED and LM_ST_UNLOCKED
911 */
912
913 static void handle_callback(struct gfs2_glock *gl, unsigned int state,
914 unsigned long delay)
915 {
916 int bit = delay ? GLF_PENDING_DEMOTE : GLF_DEMOTE;
917
918 set_bit(bit, &gl->gl_flags);
919 if (gl->gl_demote_state == LM_ST_EXCLUSIVE) {
920 gl->gl_demote_state = state;
921 gl->gl_demote_time = jiffies;
922 } else if (gl->gl_demote_state != LM_ST_UNLOCKED &&
923 gl->gl_demote_state != state) {
924 gl->gl_demote_state = LM_ST_UNLOCKED;
925 }
926 if (gl->gl_ops->go_callback)
927 gl->gl_ops->go_callback(gl);
928 trace_gfs2_demote_rq(gl);
929 }
930
931 /**
932 * gfs2_glock_wait - wait on a glock acquisition
933 * @gh: the glock holder
934 *
935 * Returns: 0 on success
936 */
937
938 int gfs2_glock_wait(struct gfs2_holder *gh)
939 {
940 wait_on_holder(gh);
941 return gh->gh_error;
942 }
943
944 void gfs2_print_dbg(struct seq_file *seq, const char *fmt, ...)
945 {
946 va_list args;
947
948 va_start(args, fmt);
949 if (seq) {
950 struct gfs2_glock_iter *gi = seq->private;
951 vsprintf(gi->string, fmt, args);
952 seq_printf(seq, gi->string);
953 } else {
954 printk(KERN_ERR " ");
955 vprintk(fmt, args);
956 }
957 va_end(args);
958 }
959
960 /**
961 * add_to_queue - Add a holder to the wait queue (but look for recursion)
962 * @gh: the holder structure to add
963 *
964 * Eventually we should move the recursive locking trap to a
965 * debugging option or something like that. This is the fast
966 * path and needs to have the minimum number of distractions.
967 *
968 */
969
970 static inline void add_to_queue(struct gfs2_holder *gh)
971 __releases(&gl->gl_spin)
972 __acquires(&gl->gl_spin)
973 {
974 struct gfs2_glock *gl = gh->gh_gl;
975 struct gfs2_sbd *sdp = gl->gl_sbd;
976 struct list_head *insert_pt = NULL;
977 struct gfs2_holder *gh2;
978 int try_lock = 0;
979
980 BUG_ON(gh->gh_owner_pid == NULL);
981 if (test_and_set_bit(HIF_WAIT, &gh->gh_iflags))
982 BUG();
983
984 if (gh->gh_flags & (LM_FLAG_TRY | LM_FLAG_TRY_1CB)) {
985 if (test_bit(GLF_LOCK, &gl->gl_flags))
986 try_lock = 1;
987 if (test_bit(GLF_INVALIDATE_IN_PROGRESS, &gl->gl_flags))
988 goto fail;
989 }
990
991 list_for_each_entry(gh2, &gl->gl_holders, gh_list) {
992 if (unlikely(gh2->gh_owner_pid == gh->gh_owner_pid &&
993 (gh->gh_gl->gl_ops->go_type != LM_TYPE_FLOCK)))
994 goto trap_recursive;
995 if (try_lock &&
996 !(gh2->gh_flags & (LM_FLAG_TRY | LM_FLAG_TRY_1CB)) &&
997 !may_grant(gl, gh)) {
998 fail:
999 gh->gh_error = GLR_TRYFAILED;
1000 gfs2_holder_wake(gh);
1001 return;
1002 }
1003 if (test_bit(HIF_HOLDER, &gh2->gh_iflags))
1004 continue;
1005 if (unlikely((gh->gh_flags & LM_FLAG_PRIORITY) && !insert_pt))
1006 insert_pt = &gh2->gh_list;
1007 }
1008 if (likely(insert_pt == NULL)) {
1009 list_add_tail(&gh->gh_list, &gl->gl_holders);
1010 if (unlikely(gh->gh_flags & LM_FLAG_PRIORITY))
1011 goto do_cancel;
1012 return;
1013 }
1014 trace_gfs2_glock_queue(gh, 1);
1015 list_add_tail(&gh->gh_list, insert_pt);
1016 do_cancel:
1017 gh = list_entry(gl->gl_holders.next, struct gfs2_holder, gh_list);
1018 if (!(gh->gh_flags & LM_FLAG_PRIORITY)) {
1019 spin_unlock(&gl->gl_spin);
1020 if (sdp->sd_lockstruct.ls_ops->lm_cancel)
1021 sdp->sd_lockstruct.ls_ops->lm_cancel(gl);
1022 spin_lock(&gl->gl_spin);
1023 }
1024 return;
1025
1026 trap_recursive:
1027 print_symbol(KERN_ERR "original: %s\n", gh2->gh_ip);
1028 printk(KERN_ERR "pid: %d\n", pid_nr(gh2->gh_owner_pid));
1029 printk(KERN_ERR "lock type: %d req lock state : %d\n",
1030 gh2->gh_gl->gl_name.ln_type, gh2->gh_state);
1031 print_symbol(KERN_ERR "new: %s\n", gh->gh_ip);
1032 printk(KERN_ERR "pid: %d\n", pid_nr(gh->gh_owner_pid));
1033 printk(KERN_ERR "lock type: %d req lock state : %d\n",
1034 gh->gh_gl->gl_name.ln_type, gh->gh_state);
1035 __dump_glock(NULL, gl);
1036 BUG();
1037 }
1038
1039 /**
1040 * gfs2_glock_nq - enqueue a struct gfs2_holder onto a glock (acquire a glock)
1041 * @gh: the holder structure
1042 *
1043 * if (gh->gh_flags & GL_ASYNC), this never returns an error
1044 *
1045 * Returns: 0, GLR_TRYFAILED, or errno on failure
1046 */
1047
1048 int gfs2_glock_nq(struct gfs2_holder *gh)
1049 {
1050 struct gfs2_glock *gl = gh->gh_gl;
1051 struct gfs2_sbd *sdp = gl->gl_sbd;
1052 int error = 0;
1053
1054 if (unlikely(test_bit(SDF_SHUTDOWN, &sdp->sd_flags)))
1055 return -EIO;
1056
1057 spin_lock(&gl->gl_spin);
1058 add_to_queue(gh);
1059 run_queue(gl, 1);
1060 spin_unlock(&gl->gl_spin);
1061
1062 if (!(gh->gh_flags & GL_ASYNC))
1063 error = gfs2_glock_wait(gh);
1064
1065 return error;
1066 }
1067
1068 /**
1069 * gfs2_glock_poll - poll to see if an async request has been completed
1070 * @gh: the holder
1071 *
1072 * Returns: 1 if the request is ready to be gfs2_glock_wait()ed on
1073 */
1074
1075 int gfs2_glock_poll(struct gfs2_holder *gh)
1076 {
1077 return test_bit(HIF_WAIT, &gh->gh_iflags) ? 0 : 1;
1078 }
1079
1080 /**
1081 * gfs2_glock_dq - dequeue a struct gfs2_holder from a glock (release a glock)
1082 * @gh: the glock holder
1083 *
1084 */
1085
1086 void gfs2_glock_dq(struct gfs2_holder *gh)
1087 {
1088 struct gfs2_glock *gl = gh->gh_gl;
1089 const struct gfs2_glock_operations *glops = gl->gl_ops;
1090 unsigned delay = 0;
1091 int fast_path = 0;
1092
1093 spin_lock(&gl->gl_spin);
1094 if (gh->gh_flags & GL_NOCACHE)
1095 handle_callback(gl, LM_ST_UNLOCKED, 0);
1096
1097 list_del_init(&gh->gh_list);
1098 if (find_first_holder(gl) == NULL) {
1099 if (glops->go_unlock) {
1100 GLOCK_BUG_ON(gl, test_and_set_bit(GLF_LOCK, &gl->gl_flags));
1101 spin_unlock(&gl->gl_spin);
1102 glops->go_unlock(gh);
1103 spin_lock(&gl->gl_spin);
1104 clear_bit(GLF_LOCK, &gl->gl_flags);
1105 }
1106 if (list_empty(&gl->gl_holders) &&
1107 !test_bit(GLF_PENDING_DEMOTE, &gl->gl_flags) &&
1108 !test_bit(GLF_DEMOTE, &gl->gl_flags))
1109 fast_path = 1;
1110 }
1111 trace_gfs2_glock_queue(gh, 0);
1112 spin_unlock(&gl->gl_spin);
1113 if (likely(fast_path))
1114 return;
1115
1116 gfs2_glock_hold(gl);
1117 if (test_bit(GLF_PENDING_DEMOTE, &gl->gl_flags) &&
1118 !test_bit(GLF_DEMOTE, &gl->gl_flags))
1119 delay = gl->gl_ops->go_min_hold_time;
1120 if (queue_delayed_work(glock_workqueue, &gl->gl_work, delay) == 0)
1121 gfs2_glock_put(gl);
1122 }
1123
1124 void gfs2_glock_dq_wait(struct gfs2_holder *gh)
1125 {
1126 struct gfs2_glock *gl = gh->gh_gl;
1127 gfs2_glock_dq(gh);
1128 wait_on_demote(gl);
1129 }
1130
1131 /**
1132 * gfs2_glock_dq_uninit - dequeue a holder from a glock and initialize it
1133 * @gh: the holder structure
1134 *
1135 */
1136
1137 void gfs2_glock_dq_uninit(struct gfs2_holder *gh)
1138 {
1139 gfs2_glock_dq(gh);
1140 gfs2_holder_uninit(gh);
1141 }
1142
1143 /**
1144 * gfs2_glock_nq_num - acquire a glock based on lock number
1145 * @sdp: the filesystem
1146 * @number: the lock number
1147 * @glops: the glock operations for the type of glock
1148 * @state: the state to acquire the glock in
1149 * @flags: modifier flags for the aquisition
1150 * @gh: the struct gfs2_holder
1151 *
1152 * Returns: errno
1153 */
1154
1155 int gfs2_glock_nq_num(struct gfs2_sbd *sdp, u64 number,
1156 const struct gfs2_glock_operations *glops,
1157 unsigned int state, int flags, struct gfs2_holder *gh)
1158 {
1159 struct gfs2_glock *gl;
1160 int error;
1161
1162 error = gfs2_glock_get(sdp, number, glops, CREATE, &gl);
1163 if (!error) {
1164 error = gfs2_glock_nq_init(gl, state, flags, gh);
1165 gfs2_glock_put(gl);
1166 }
1167
1168 return error;
1169 }
1170
1171 /**
1172 * glock_compare - Compare two struct gfs2_glock structures for sorting
1173 * @arg_a: the first structure
1174 * @arg_b: the second structure
1175 *
1176 */
1177
1178 static int glock_compare(const void *arg_a, const void *arg_b)
1179 {
1180 const struct gfs2_holder *gh_a = *(const struct gfs2_holder **)arg_a;
1181 const struct gfs2_holder *gh_b = *(const struct gfs2_holder **)arg_b;
1182 const struct lm_lockname *a = &gh_a->gh_gl->gl_name;
1183 const struct lm_lockname *b = &gh_b->gh_gl->gl_name;
1184
1185 if (a->ln_number > b->ln_number)
1186 return 1;
1187 if (a->ln_number < b->ln_number)
1188 return -1;
1189 BUG_ON(gh_a->gh_gl->gl_ops->go_type == gh_b->gh_gl->gl_ops->go_type);
1190 return 0;
1191 }
1192
1193 /**
1194 * nq_m_sync - synchonously acquire more than one glock in deadlock free order
1195 * @num_gh: the number of structures
1196 * @ghs: an array of struct gfs2_holder structures
1197 *
1198 * Returns: 0 on success (all glocks acquired),
1199 * errno on failure (no glocks acquired)
1200 */
1201
1202 static int nq_m_sync(unsigned int num_gh, struct gfs2_holder *ghs,
1203 struct gfs2_holder **p)
1204 {
1205 unsigned int x;
1206 int error = 0;
1207
1208 for (x = 0; x < num_gh; x++)
1209 p[x] = &ghs[x];
1210
1211 sort(p, num_gh, sizeof(struct gfs2_holder *), glock_compare, NULL);
1212
1213 for (x = 0; x < num_gh; x++) {
1214 p[x]->gh_flags &= ~(LM_FLAG_TRY | GL_ASYNC);
1215
1216 error = gfs2_glock_nq(p[x]);
1217 if (error) {
1218 while (x--)
1219 gfs2_glock_dq(p[x]);
1220 break;
1221 }
1222 }
1223
1224 return error;
1225 }
1226
1227 /**
1228 * gfs2_glock_nq_m - acquire multiple glocks
1229 * @num_gh: the number of structures
1230 * @ghs: an array of struct gfs2_holder structures
1231 *
1232 *
1233 * Returns: 0 on success (all glocks acquired),
1234 * errno on failure (no glocks acquired)
1235 */
1236
1237 int gfs2_glock_nq_m(unsigned int num_gh, struct gfs2_holder *ghs)
1238 {
1239 struct gfs2_holder *tmp[4];
1240 struct gfs2_holder **pph = tmp;
1241 int error = 0;
1242
1243 switch(num_gh) {
1244 case 0:
1245 return 0;
1246 case 1:
1247 ghs->gh_flags &= ~(LM_FLAG_TRY | GL_ASYNC);
1248 return gfs2_glock_nq(ghs);
1249 default:
1250 if (num_gh <= 4)
1251 break;
1252 pph = kmalloc(num_gh * sizeof(struct gfs2_holder *), GFP_NOFS);
1253 if (!pph)
1254 return -ENOMEM;
1255 }
1256
1257 error = nq_m_sync(num_gh, ghs, pph);
1258
1259 if (pph != tmp)
1260 kfree(pph);
1261
1262 return error;
1263 }
1264
1265 /**
1266 * gfs2_glock_dq_m - release multiple glocks
1267 * @num_gh: the number of structures
1268 * @ghs: an array of struct gfs2_holder structures
1269 *
1270 */
1271
1272 void gfs2_glock_dq_m(unsigned int num_gh, struct gfs2_holder *ghs)
1273 {
1274 unsigned int x;
1275
1276 for (x = 0; x < num_gh; x++)
1277 gfs2_glock_dq(&ghs[x]);
1278 }
1279
1280 /**
1281 * gfs2_glock_dq_uninit_m - release multiple glocks
1282 * @num_gh: the number of structures
1283 * @ghs: an array of struct gfs2_holder structures
1284 *
1285 */
1286
1287 void gfs2_glock_dq_uninit_m(unsigned int num_gh, struct gfs2_holder *ghs)
1288 {
1289 unsigned int x;
1290
1291 for (x = 0; x < num_gh; x++)
1292 gfs2_glock_dq_uninit(&ghs[x]);
1293 }
1294
1295 void gfs2_glock_cb(struct gfs2_glock *gl, unsigned int state)
1296 {
1297 unsigned long delay = 0;
1298 unsigned long holdtime;
1299 unsigned long now = jiffies;
1300
1301 gfs2_glock_hold(gl);
1302 holdtime = gl->gl_tchange + gl->gl_ops->go_min_hold_time;
1303 if (time_before(now, holdtime))
1304 delay = holdtime - now;
1305 if (test_bit(GLF_REPLY_PENDING, &gl->gl_flags))
1306 delay = gl->gl_ops->go_min_hold_time;
1307
1308 spin_lock(&gl->gl_spin);
1309 handle_callback(gl, state, delay);
1310 spin_unlock(&gl->gl_spin);
1311 if (queue_delayed_work(glock_workqueue, &gl->gl_work, delay) == 0)
1312 gfs2_glock_put(gl);
1313 }
1314
1315 /**
1316 * gfs2_glock_complete - Callback used by locking
1317 * @gl: Pointer to the glock
1318 * @ret: The return value from the dlm
1319 *
1320 */
1321
1322 void gfs2_glock_complete(struct gfs2_glock *gl, int ret)
1323 {
1324 struct lm_lockstruct *ls = &gl->gl_sbd->sd_lockstruct;
1325 gl->gl_reply = ret;
1326 if (unlikely(test_bit(DFL_BLOCK_LOCKS, &ls->ls_flags))) {
1327 struct gfs2_holder *gh;
1328 spin_lock(&gl->gl_spin);
1329 gh = find_first_waiter(gl);
1330 if ((!(gh && (gh->gh_flags & LM_FLAG_NOEXP)) &&
1331 (gl->gl_target != LM_ST_UNLOCKED)) ||
1332 ((ret & ~LM_OUT_ST_MASK) != 0))
1333 set_bit(GLF_FROZEN, &gl->gl_flags);
1334 spin_unlock(&gl->gl_spin);
1335 if (test_bit(GLF_FROZEN, &gl->gl_flags))
1336 return;
1337 }
1338 set_bit(GLF_REPLY_PENDING, &gl->gl_flags);
1339 gfs2_glock_hold(gl);
1340 if (queue_delayed_work(glock_workqueue, &gl->gl_work, 0) == 0)
1341 gfs2_glock_put(gl);
1342 }
1343
1344
1345 static int gfs2_shrink_glock_memory(int nr, gfp_t gfp_mask)
1346 {
1347 struct gfs2_glock *gl;
1348 int may_demote;
1349 int nr_skipped = 0;
1350 LIST_HEAD(skipped);
1351
1352 if (nr == 0)
1353 goto out;
1354
1355 if (!(gfp_mask & __GFP_FS))
1356 return -1;
1357
1358 spin_lock(&lru_lock);
1359 while(nr && !list_empty(&lru_list)) {
1360 gl = list_entry(lru_list.next, struct gfs2_glock, gl_lru);
1361 list_del_init(&gl->gl_lru);
1362 atomic_dec(&lru_count);
1363
1364 /* Check if glock is about to be freed */
1365 if (atomic_read(&gl->gl_ref) == 0)
1366 continue;
1367
1368 /* Test for being demotable */
1369 if (!test_and_set_bit(GLF_LOCK, &gl->gl_flags)) {
1370 gfs2_glock_hold(gl);
1371 spin_unlock(&lru_lock);
1372 spin_lock(&gl->gl_spin);
1373 may_demote = demote_ok(gl);
1374 if (may_demote) {
1375 handle_callback(gl, LM_ST_UNLOCKED, 0);
1376 nr--;
1377 }
1378 if (queue_delayed_work(glock_workqueue, &gl->gl_work, 0) == 0)
1379 gfs2_glock_put_nolock(gl);
1380 spin_unlock(&gl->gl_spin);
1381 clear_bit(GLF_LOCK, &gl->gl_flags);
1382 spin_lock(&lru_lock);
1383 continue;
1384 }
1385 nr_skipped++;
1386 list_add(&gl->gl_lru, &skipped);
1387 }
1388 list_splice(&skipped, &lru_list);
1389 atomic_add(nr_skipped, &lru_count);
1390 spin_unlock(&lru_lock);
1391 out:
1392 return (atomic_read(&lru_count) / 100) * sysctl_vfs_cache_pressure;
1393 }
1394
1395 static struct shrinker glock_shrinker = {
1396 .shrink = gfs2_shrink_glock_memory,
1397 .seeks = DEFAULT_SEEKS,
1398 };
1399
1400 /**
1401 * examine_bucket - Call a function for glock in a hash bucket
1402 * @examiner: the function
1403 * @sdp: the filesystem
1404 * @bucket: the bucket
1405 *
1406 * Returns: 1 if the bucket has entries
1407 */
1408
1409 static int examine_bucket(glock_examiner examiner, struct gfs2_sbd *sdp,
1410 unsigned int hash)
1411 {
1412 struct gfs2_glock *gl, *prev = NULL;
1413 int has_entries = 0;
1414 struct hlist_head *head = &gl_hash_table[hash].hb_list;
1415
1416 read_lock(gl_lock_addr(hash));
1417 /* Can't use hlist_for_each_entry - don't want prefetch here */
1418 if (hlist_empty(head))
1419 goto out;
1420 gl = list_entry(head->first, struct gfs2_glock, gl_list);
1421 while(1) {
1422 if (!sdp || gl->gl_sbd == sdp) {
1423 gfs2_glock_hold(gl);
1424 read_unlock(gl_lock_addr(hash));
1425 if (prev)
1426 gfs2_glock_put(prev);
1427 prev = gl;
1428 examiner(gl);
1429 has_entries = 1;
1430 read_lock(gl_lock_addr(hash));
1431 }
1432 if (gl->gl_list.next == NULL)
1433 break;
1434 gl = list_entry(gl->gl_list.next, struct gfs2_glock, gl_list);
1435 }
1436 out:
1437 read_unlock(gl_lock_addr(hash));
1438 if (prev)
1439 gfs2_glock_put(prev);
1440 cond_resched();
1441 return has_entries;
1442 }
1443
1444
1445 /**
1446 * thaw_glock - thaw out a glock which has an unprocessed reply waiting
1447 * @gl: The glock to thaw
1448 *
1449 * N.B. When we freeze a glock, we leave a ref to the glock outstanding,
1450 * so this has to result in the ref count being dropped by one.
1451 */
1452
1453 static void thaw_glock(struct gfs2_glock *gl)
1454 {
1455 if (!test_and_clear_bit(GLF_FROZEN, &gl->gl_flags))
1456 return;
1457 set_bit(GLF_REPLY_PENDING, &gl->gl_flags);
1458 gfs2_glock_hold(gl);
1459 if (queue_delayed_work(glock_workqueue, &gl->gl_work, 0) == 0)
1460 gfs2_glock_put(gl);
1461 }
1462
1463 /**
1464 * clear_glock - look at a glock and see if we can free it from glock cache
1465 * @gl: the glock to look at
1466 *
1467 */
1468
1469 static void clear_glock(struct gfs2_glock *gl)
1470 {
1471 spin_lock(&lru_lock);
1472 if (!list_empty(&gl->gl_lru)) {
1473 list_del_init(&gl->gl_lru);
1474 atomic_dec(&lru_count);
1475 }
1476 spin_unlock(&lru_lock);
1477
1478 spin_lock(&gl->gl_spin);
1479 if (find_first_holder(gl) == NULL && gl->gl_state != LM_ST_UNLOCKED)
1480 handle_callback(gl, LM_ST_UNLOCKED, 0);
1481 spin_unlock(&gl->gl_spin);
1482 gfs2_glock_hold(gl);
1483 if (queue_delayed_work(glock_workqueue, &gl->gl_work, 0) == 0)
1484 gfs2_glock_put(gl);
1485 }
1486
1487 /**
1488 * gfs2_glock_thaw - Thaw any frozen glocks
1489 * @sdp: The super block
1490 *
1491 */
1492
1493 void gfs2_glock_thaw(struct gfs2_sbd *sdp)
1494 {
1495 unsigned x;
1496
1497 for (x = 0; x < GFS2_GL_HASH_SIZE; x++)
1498 examine_bucket(thaw_glock, sdp, x);
1499 }
1500
1501 /**
1502 * gfs2_gl_hash_clear - Empty out the glock hash table
1503 * @sdp: the filesystem
1504 * @wait: wait until it's all gone
1505 *
1506 * Called when unmounting the filesystem.
1507 */
1508
1509 void gfs2_gl_hash_clear(struct gfs2_sbd *sdp)
1510 {
1511 unsigned long t;
1512 unsigned int x;
1513 int cont;
1514
1515 t = jiffies;
1516
1517 for (;;) {
1518 cont = 0;
1519 for (x = 0; x < GFS2_GL_HASH_SIZE; x++) {
1520 if (examine_bucket(clear_glock, sdp, x))
1521 cont = 1;
1522 }
1523
1524 if (!cont)
1525 break;
1526
1527 if (time_after_eq(jiffies,
1528 t + gfs2_tune_get(sdp, gt_stall_secs) * HZ)) {
1529 fs_warn(sdp, "Unmount seems to be stalled. "
1530 "Dumping lock state...\n");
1531 gfs2_dump_lockstate(sdp);
1532 t = jiffies;
1533 }
1534
1535 down_write(&gfs2_umount_flush_sem);
1536 invalidate_inodes(sdp->sd_vfs);
1537 up_write(&gfs2_umount_flush_sem);
1538 msleep(10);
1539 }
1540 }
1541
1542 void gfs2_glock_finish_truncate(struct gfs2_inode *ip)
1543 {
1544 struct gfs2_glock *gl = ip->i_gl;
1545 int ret;
1546
1547 ret = gfs2_truncatei_resume(ip);
1548 gfs2_assert_withdraw(gl->gl_sbd, ret == 0);
1549
1550 spin_lock(&gl->gl_spin);
1551 clear_bit(GLF_LOCK, &gl->gl_flags);
1552 run_queue(gl, 1);
1553 spin_unlock(&gl->gl_spin);
1554 }
1555
1556 static const char *state2str(unsigned state)
1557 {
1558 switch(state) {
1559 case LM_ST_UNLOCKED:
1560 return "UN";
1561 case LM_ST_SHARED:
1562 return "SH";
1563 case LM_ST_DEFERRED:
1564 return "DF";
1565 case LM_ST_EXCLUSIVE:
1566 return "EX";
1567 }
1568 return "??";
1569 }
1570
1571 static const char *hflags2str(char *buf, unsigned flags, unsigned long iflags)
1572 {
1573 char *p = buf;
1574 if (flags & LM_FLAG_TRY)
1575 *p++ = 't';
1576 if (flags & LM_FLAG_TRY_1CB)
1577 *p++ = 'T';
1578 if (flags & LM_FLAG_NOEXP)
1579 *p++ = 'e';
1580 if (flags & LM_FLAG_ANY)
1581 *p++ = 'A';
1582 if (flags & LM_FLAG_PRIORITY)
1583 *p++ = 'p';
1584 if (flags & GL_ASYNC)
1585 *p++ = 'a';
1586 if (flags & GL_EXACT)
1587 *p++ = 'E';
1588 if (flags & GL_NOCACHE)
1589 *p++ = 'c';
1590 if (test_bit(HIF_HOLDER, &iflags))
1591 *p++ = 'H';
1592 if (test_bit(HIF_WAIT, &iflags))
1593 *p++ = 'W';
1594 if (test_bit(HIF_FIRST, &iflags))
1595 *p++ = 'F';
1596 *p = 0;
1597 return buf;
1598 }
1599
1600 /**
1601 * dump_holder - print information about a glock holder
1602 * @seq: the seq_file struct
1603 * @gh: the glock holder
1604 *
1605 * Returns: 0 on success, -ENOBUFS when we run out of space
1606 */
1607
1608 static int dump_holder(struct seq_file *seq, const struct gfs2_holder *gh)
1609 {
1610 struct task_struct *gh_owner = NULL;
1611 char buffer[KSYM_SYMBOL_LEN];
1612 char flags_buf[32];
1613
1614 sprint_symbol(buffer, gh->gh_ip);
1615 if (gh->gh_owner_pid)
1616 gh_owner = pid_task(gh->gh_owner_pid, PIDTYPE_PID);
1617 gfs2_print_dbg(seq, " H: s:%s f:%s e:%d p:%ld [%s] %s\n",
1618 state2str(gh->gh_state),
1619 hflags2str(flags_buf, gh->gh_flags, gh->gh_iflags),
1620 gh->gh_error,
1621 gh->gh_owner_pid ? (long)pid_nr(gh->gh_owner_pid) : -1,
1622 gh_owner ? gh_owner->comm : "(ended)", buffer);
1623 return 0;
1624 }
1625
1626 static const char *gflags2str(char *buf, const unsigned long *gflags)
1627 {
1628 char *p = buf;
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 *p = 0;
1650 return buf;
1651 }
1652
1653 /**
1654 * __dump_glock - print information about a glock
1655 * @seq: The seq_file struct
1656 * @gl: the glock
1657 *
1658 * The file format is as follows:
1659 * One line per object, capital letters are used to indicate objects
1660 * G = glock, I = Inode, R = rgrp, H = holder. Glocks are not indented,
1661 * other objects are indented by a single space and follow the glock to
1662 * which they are related. Fields are indicated by lower case letters
1663 * followed by a colon and the field value, except for strings which are in
1664 * [] so that its possible to see if they are composed of spaces for
1665 * example. The field's are n = number (id of the object), f = flags,
1666 * t = type, s = state, r = refcount, e = error, p = pid.
1667 *
1668 * Returns: 0 on success, -ENOBUFS when we run out of space
1669 */
1670
1671 static int __dump_glock(struct seq_file *seq, const struct gfs2_glock *gl)
1672 {
1673 const struct gfs2_glock_operations *glops = gl->gl_ops;
1674 unsigned long long dtime;
1675 const struct gfs2_holder *gh;
1676 char gflags_buf[32];
1677 int error = 0;
1678
1679 dtime = jiffies - gl->gl_demote_time;
1680 dtime *= 1000000/HZ; /* demote time in uSec */
1681 if (!test_bit(GLF_DEMOTE, &gl->gl_flags))
1682 dtime = 0;
1683 gfs2_print_dbg(seq, "G: s:%s n:%u/%llu f:%s t:%s d:%s/%llu a:%d r:%d\n",
1684 state2str(gl->gl_state),
1685 gl->gl_name.ln_type,
1686 (unsigned long long)gl->gl_name.ln_number,
1687 gflags2str(gflags_buf, &gl->gl_flags),
1688 state2str(gl->gl_target),
1689 state2str(gl->gl_demote_state), dtime,
1690 atomic_read(&gl->gl_ail_count),
1691 atomic_read(&gl->gl_ref));
1692
1693 list_for_each_entry(gh, &gl->gl_holders, gh_list) {
1694 error = dump_holder(seq, gh);
1695 if (error)
1696 goto out;
1697 }
1698 if (gl->gl_state != LM_ST_UNLOCKED && glops->go_dump)
1699 error = glops->go_dump(seq, gl);
1700 out:
1701 return error;
1702 }
1703
1704 static int dump_glock(struct seq_file *seq, struct gfs2_glock *gl)
1705 {
1706 int ret;
1707 spin_lock(&gl->gl_spin);
1708 ret = __dump_glock(seq, gl);
1709 spin_unlock(&gl->gl_spin);
1710 return ret;
1711 }
1712
1713 /**
1714 * gfs2_dump_lockstate - print out the current lockstate
1715 * @sdp: the filesystem
1716 * @ub: the buffer to copy the information into
1717 *
1718 * If @ub is NULL, dump the lockstate to the console.
1719 *
1720 */
1721
1722 static int gfs2_dump_lockstate(struct gfs2_sbd *sdp)
1723 {
1724 struct gfs2_glock *gl;
1725 struct hlist_node *h;
1726 unsigned int x;
1727 int error = 0;
1728
1729 for (x = 0; x < GFS2_GL_HASH_SIZE; x++) {
1730
1731 read_lock(gl_lock_addr(x));
1732
1733 hlist_for_each_entry(gl, h, &gl_hash_table[x].hb_list, gl_list) {
1734 if (gl->gl_sbd != sdp)
1735 continue;
1736
1737 error = dump_glock(NULL, gl);
1738 if (error)
1739 break;
1740 }
1741
1742 read_unlock(gl_lock_addr(x));
1743
1744 if (error)
1745 break;
1746 }
1747
1748
1749 return error;
1750 }
1751
1752
1753 int __init gfs2_glock_init(void)
1754 {
1755 unsigned i;
1756 for(i = 0; i < GFS2_GL_HASH_SIZE; i++) {
1757 INIT_HLIST_HEAD(&gl_hash_table[i].hb_list);
1758 }
1759 #ifdef GL_HASH_LOCK_SZ
1760 for(i = 0; i < GL_HASH_LOCK_SZ; i++) {
1761 rwlock_init(&gl_hash_locks[i]);
1762 }
1763 #endif
1764
1765 glock_workqueue = create_workqueue("glock_workqueue");
1766 if (IS_ERR(glock_workqueue))
1767 return PTR_ERR(glock_workqueue);
1768 gfs2_delete_workqueue = create_workqueue("delete_workqueue");
1769 if (IS_ERR(gfs2_delete_workqueue)) {
1770 destroy_workqueue(glock_workqueue);
1771 return PTR_ERR(gfs2_delete_workqueue);
1772 }
1773
1774 register_shrinker(&glock_shrinker);
1775
1776 return 0;
1777 }
1778
1779 void gfs2_glock_exit(void)
1780 {
1781 unregister_shrinker(&glock_shrinker);
1782 destroy_workqueue(glock_workqueue);
1783 destroy_workqueue(gfs2_delete_workqueue);
1784 }
1785
1786 static int gfs2_glock_iter_next(struct gfs2_glock_iter *gi)
1787 {
1788 struct gfs2_glock *gl;
1789
1790 restart:
1791 read_lock(gl_lock_addr(gi->hash));
1792 gl = gi->gl;
1793 if (gl) {
1794 gi->gl = hlist_entry(gl->gl_list.next,
1795 struct gfs2_glock, gl_list);
1796 } else {
1797 gi->gl = hlist_entry(gl_hash_table[gi->hash].hb_list.first,
1798 struct gfs2_glock, gl_list);
1799 }
1800 if (gi->gl)
1801 gfs2_glock_hold(gi->gl);
1802 read_unlock(gl_lock_addr(gi->hash));
1803 if (gl)
1804 gfs2_glock_put(gl);
1805 while (gi->gl == NULL) {
1806 gi->hash++;
1807 if (gi->hash >= GFS2_GL_HASH_SIZE)
1808 return 1;
1809 read_lock(gl_lock_addr(gi->hash));
1810 gi->gl = hlist_entry(gl_hash_table[gi->hash].hb_list.first,
1811 struct gfs2_glock, gl_list);
1812 if (gi->gl)
1813 gfs2_glock_hold(gi->gl);
1814 read_unlock(gl_lock_addr(gi->hash));
1815 }
1816
1817 if (gi->sdp != gi->gl->gl_sbd)
1818 goto restart;
1819
1820 return 0;
1821 }
1822
1823 static void gfs2_glock_iter_free(struct gfs2_glock_iter *gi)
1824 {
1825 if (gi->gl)
1826 gfs2_glock_put(gi->gl);
1827 gi->gl = NULL;
1828 }
1829
1830 static void *gfs2_glock_seq_start(struct seq_file *seq, loff_t *pos)
1831 {
1832 struct gfs2_glock_iter *gi = seq->private;
1833 loff_t n = *pos;
1834
1835 gi->hash = 0;
1836
1837 do {
1838 if (gfs2_glock_iter_next(gi)) {
1839 gfs2_glock_iter_free(gi);
1840 return NULL;
1841 }
1842 } while (n--);
1843
1844 return gi->gl;
1845 }
1846
1847 static void *gfs2_glock_seq_next(struct seq_file *seq, void *iter_ptr,
1848 loff_t *pos)
1849 {
1850 struct gfs2_glock_iter *gi = seq->private;
1851
1852 (*pos)++;
1853
1854 if (gfs2_glock_iter_next(gi)) {
1855 gfs2_glock_iter_free(gi);
1856 return NULL;
1857 }
1858
1859 return gi->gl;
1860 }
1861
1862 static void gfs2_glock_seq_stop(struct seq_file *seq, void *iter_ptr)
1863 {
1864 struct gfs2_glock_iter *gi = seq->private;
1865 gfs2_glock_iter_free(gi);
1866 }
1867
1868 static int gfs2_glock_seq_show(struct seq_file *seq, void *iter_ptr)
1869 {
1870 return dump_glock(seq, iter_ptr);
1871 }
1872
1873 static const struct seq_operations gfs2_glock_seq_ops = {
1874 .start = gfs2_glock_seq_start,
1875 .next = gfs2_glock_seq_next,
1876 .stop = gfs2_glock_seq_stop,
1877 .show = gfs2_glock_seq_show,
1878 };
1879
1880 static int gfs2_debugfs_open(struct inode *inode, struct file *file)
1881 {
1882 int ret = seq_open_private(file, &gfs2_glock_seq_ops,
1883 sizeof(struct gfs2_glock_iter));
1884 if (ret == 0) {
1885 struct seq_file *seq = file->private_data;
1886 struct gfs2_glock_iter *gi = seq->private;
1887 gi->sdp = inode->i_private;
1888 }
1889 return ret;
1890 }
1891
1892 static const struct file_operations gfs2_debug_fops = {
1893 .owner = THIS_MODULE,
1894 .open = gfs2_debugfs_open,
1895 .read = seq_read,
1896 .llseek = seq_lseek,
1897 .release = seq_release_private,
1898 };
1899
1900 int gfs2_create_debugfs_file(struct gfs2_sbd *sdp)
1901 {
1902 sdp->debugfs_dir = debugfs_create_dir(sdp->sd_table_name, gfs2_root);
1903 if (!sdp->debugfs_dir)
1904 return -ENOMEM;
1905 sdp->debugfs_dentry_glocks = debugfs_create_file("glocks",
1906 S_IFREG | S_IRUGO,
1907 sdp->debugfs_dir, sdp,
1908 &gfs2_debug_fops);
1909 if (!sdp->debugfs_dentry_glocks)
1910 return -ENOMEM;
1911
1912 return 0;
1913 }
1914
1915 void gfs2_delete_debugfs_file(struct gfs2_sbd *sdp)
1916 {
1917 if (sdp && sdp->debugfs_dir) {
1918 if (sdp->debugfs_dentry_glocks) {
1919 debugfs_remove(sdp->debugfs_dentry_glocks);
1920 sdp->debugfs_dentry_glocks = NULL;
1921 }
1922 debugfs_remove(sdp->debugfs_dir);
1923 sdp->debugfs_dir = NULL;
1924 }
1925 }
1926
1927 int gfs2_register_debugfs(void)
1928 {
1929 gfs2_root = debugfs_create_dir("gfs2", NULL);
1930 return gfs2_root ? 0 : -ENOMEM;
1931 }
1932
1933 void gfs2_unregister_debugfs(void)
1934 {
1935 debugfs_remove(gfs2_root);
1936 gfs2_root = NULL;
1937 }
1938
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