1 // SPDX-License-Identifier: GPL-2.0-only
3 * Copyright (C) Sistina Software, Inc. 1997-2003 All rights reserved.
4 * Copyright (C) 2004-2008 Red Hat, Inc. All rights reserved.
7 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
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>
48 #define CREATE_TRACE_POINTS
49 #include "trace_gfs2.h"
51 struct gfs2_glock_iter {
52 struct gfs2_sbd *sdp; /* incore superblock */
53 struct rhashtable_iter hti; /* rhashtable iterator */
54 struct gfs2_glock *gl; /* current glock struct */
55 loff_t last_pos; /* last position */
58 typedef void (*glock_examiner) (struct gfs2_glock * gl);
60 static void do_xmote(struct gfs2_glock *gl, struct gfs2_holder *gh, unsigned int target);
62 static struct dentry *gfs2_root;
63 static struct workqueue_struct *glock_workqueue;
64 struct workqueue_struct *gfs2_delete_workqueue;
65 static LIST_HEAD(lru_list);
66 static atomic_t lru_count = ATOMIC_INIT(0);
67 static DEFINE_SPINLOCK(lru_lock);
69 #define GFS2_GL_HASH_SHIFT 15
70 #define GFS2_GL_HASH_SIZE BIT(GFS2_GL_HASH_SHIFT)
72 static const struct rhashtable_params ht_parms = {
73 .nelem_hint = GFS2_GL_HASH_SIZE * 3 / 4,
74 .key_len = offsetofend(struct lm_lockname, ln_type),
75 .key_offset = offsetof(struct gfs2_glock, gl_name),
76 .head_offset = offsetof(struct gfs2_glock, gl_node),
79 static struct rhashtable gl_hash_table;
81 #define GLOCK_WAIT_TABLE_BITS 12
82 #define GLOCK_WAIT_TABLE_SIZE (1 << GLOCK_WAIT_TABLE_BITS)
83 static wait_queue_head_t glock_wait_table[GLOCK_WAIT_TABLE_SIZE] __cacheline_aligned;
85 struct wait_glock_queue {
86 struct lm_lockname *name;
87 wait_queue_entry_t wait;
90 static int glock_wake_function(wait_queue_entry_t *wait, unsigned int mode,
93 struct wait_glock_queue *wait_glock =
94 container_of(wait, struct wait_glock_queue, wait);
95 struct lm_lockname *wait_name = wait_glock->name;
96 struct lm_lockname *wake_name = key;
98 if (wake_name->ln_sbd != wait_name->ln_sbd ||
99 wake_name->ln_number != wait_name->ln_number ||
100 wake_name->ln_type != wait_name->ln_type)
102 return autoremove_wake_function(wait, mode, sync, key);
105 static wait_queue_head_t *glock_waitqueue(struct lm_lockname *name)
107 u32 hash = jhash2((u32 *)name, ht_parms.key_len / 4, 0);
109 return glock_wait_table + hash_32(hash, GLOCK_WAIT_TABLE_BITS);
113 * wake_up_glock - Wake up waiters on a glock
116 static void wake_up_glock(struct gfs2_glock *gl)
118 wait_queue_head_t *wq = glock_waitqueue(&gl->gl_name);
120 if (waitqueue_active(wq))
121 __wake_up(wq, TASK_NORMAL, 1, &gl->gl_name);
124 static void gfs2_glock_dealloc(struct rcu_head *rcu)
126 struct gfs2_glock *gl = container_of(rcu, struct gfs2_glock, gl_rcu);
128 if (gl->gl_ops->go_flags & GLOF_ASPACE) {
129 kmem_cache_free(gfs2_glock_aspace_cachep, gl);
131 kfree(gl->gl_lksb.sb_lvbptr);
132 kmem_cache_free(gfs2_glock_cachep, gl);
136 void gfs2_glock_free(struct gfs2_glock *gl)
138 struct gfs2_sbd *sdp = gl->gl_name.ln_sbd;
140 BUG_ON(atomic_read(&gl->gl_revokes));
141 rhashtable_remove_fast(&gl_hash_table, &gl->gl_node, ht_parms);
144 call_rcu(&gl->gl_rcu, gfs2_glock_dealloc);
145 if (atomic_dec_and_test(&sdp->sd_glock_disposal))
146 wake_up(&sdp->sd_glock_wait);
150 * gfs2_glock_hold() - increment reference count on glock
151 * @gl: The glock to hold
155 void gfs2_glock_hold(struct gfs2_glock *gl)
157 GLOCK_BUG_ON(gl, __lockref_is_dead(&gl->gl_lockref));
158 lockref_get(&gl->gl_lockref);
162 * demote_ok - Check to see if it's ok to unlock a glock
165 * Returns: 1 if it's ok
168 static int demote_ok(const struct gfs2_glock *gl)
170 const struct gfs2_glock_operations *glops = gl->gl_ops;
172 if (gl->gl_state == LM_ST_UNLOCKED)
174 if (!list_empty(&gl->gl_holders))
176 if (glops->go_demote_ok)
177 return glops->go_demote_ok(gl);
182 void gfs2_glock_add_to_lru(struct gfs2_glock *gl)
184 if (!(gl->gl_ops->go_flags & GLOF_LRU))
187 spin_lock(&lru_lock);
189 list_del(&gl->gl_lru);
190 list_add_tail(&gl->gl_lru, &lru_list);
192 if (!test_bit(GLF_LRU, &gl->gl_flags)) {
193 set_bit(GLF_LRU, &gl->gl_flags);
194 atomic_inc(&lru_count);
197 spin_unlock(&lru_lock);
200 static void gfs2_glock_remove_from_lru(struct gfs2_glock *gl)
202 if (!(gl->gl_ops->go_flags & GLOF_LRU))
205 spin_lock(&lru_lock);
206 if (test_bit(GLF_LRU, &gl->gl_flags)) {
207 list_del_init(&gl->gl_lru);
208 atomic_dec(&lru_count);
209 clear_bit(GLF_LRU, &gl->gl_flags);
211 spin_unlock(&lru_lock);
215 * Enqueue the glock on the work queue. Passes one glock reference on to the
218 static void __gfs2_glock_queue_work(struct gfs2_glock *gl, unsigned long delay) {
219 if (!queue_delayed_work(glock_workqueue, &gl->gl_work, delay)) {
221 * We are holding the lockref spinlock, and the work was still
222 * queued above. The queued work (glock_work_func) takes that
223 * spinlock before dropping its glock reference(s), so it
224 * cannot have dropped them in the meantime.
226 GLOCK_BUG_ON(gl, gl->gl_lockref.count < 2);
227 gl->gl_lockref.count--;
231 static void gfs2_glock_queue_work(struct gfs2_glock *gl, unsigned long delay) {
232 spin_lock(&gl->gl_lockref.lock);
233 __gfs2_glock_queue_work(gl, delay);
234 spin_unlock(&gl->gl_lockref.lock);
237 static void __gfs2_glock_put(struct gfs2_glock *gl)
239 struct gfs2_sbd *sdp = gl->gl_name.ln_sbd;
240 struct address_space *mapping = gfs2_glock2aspace(gl);
242 lockref_mark_dead(&gl->gl_lockref);
244 gfs2_glock_remove_from_lru(gl);
245 spin_unlock(&gl->gl_lockref.lock);
246 GLOCK_BUG_ON(gl, !list_empty(&gl->gl_holders));
247 GLOCK_BUG_ON(gl, mapping && mapping->nrpages);
248 trace_gfs2_glock_put(gl);
249 sdp->sd_lockstruct.ls_ops->lm_put_lock(gl);
253 * Cause the glock to be put in work queue context.
255 void gfs2_glock_queue_put(struct gfs2_glock *gl)
257 gfs2_glock_queue_work(gl, 0);
261 * gfs2_glock_put() - Decrement reference count on glock
262 * @gl: The glock to put
266 void gfs2_glock_put(struct gfs2_glock *gl)
268 if (lockref_put_or_lock(&gl->gl_lockref))
271 __gfs2_glock_put(gl);
275 * may_grant - check if its ok to grant a new lock
277 * @gh: The lock request which we wish to grant
279 * Returns: true if its ok to grant the lock
282 static inline int may_grant(const struct gfs2_glock *gl, const struct gfs2_holder *gh)
284 const struct gfs2_holder *gh_head = list_entry(gl->gl_holders.next, const struct gfs2_holder, gh_list);
285 if ((gh->gh_state == LM_ST_EXCLUSIVE ||
286 gh_head->gh_state == LM_ST_EXCLUSIVE) && gh != gh_head)
288 if (gl->gl_state == gh->gh_state)
290 if (gh->gh_flags & GL_EXACT)
292 if (gl->gl_state == LM_ST_EXCLUSIVE) {
293 if (gh->gh_state == LM_ST_SHARED && gh_head->gh_state == LM_ST_SHARED)
295 if (gh->gh_state == LM_ST_DEFERRED && gh_head->gh_state == LM_ST_DEFERRED)
298 if (gl->gl_state != LM_ST_UNLOCKED && (gh->gh_flags & LM_FLAG_ANY))
303 static void gfs2_holder_wake(struct gfs2_holder *gh)
305 clear_bit(HIF_WAIT, &gh->gh_iflags);
306 smp_mb__after_atomic();
307 wake_up_bit(&gh->gh_iflags, HIF_WAIT);
311 * do_error - Something unexpected has happened during a lock request
315 static void do_error(struct gfs2_glock *gl, const int ret)
317 struct gfs2_holder *gh, *tmp;
319 list_for_each_entry_safe(gh, tmp, &gl->gl_holders, gh_list) {
320 if (test_bit(HIF_HOLDER, &gh->gh_iflags))
322 if (ret & LM_OUT_ERROR)
324 else if (gh->gh_flags & (LM_FLAG_TRY | LM_FLAG_TRY_1CB))
325 gh->gh_error = GLR_TRYFAILED;
328 list_del_init(&gh->gh_list);
329 trace_gfs2_glock_queue(gh, 0);
330 gfs2_holder_wake(gh);
335 * do_promote - promote as many requests as possible on the current queue
338 * Returns: 1 if there is a blocked holder at the head of the list, or 2
339 * if a type specific operation is underway.
342 static int do_promote(struct gfs2_glock *gl)
343 __releases(&gl->gl_lockref.lock)
344 __acquires(&gl->gl_lockref.lock)
346 const struct gfs2_glock_operations *glops = gl->gl_ops;
347 struct gfs2_holder *gh, *tmp;
351 list_for_each_entry_safe(gh, tmp, &gl->gl_holders, gh_list) {
352 if (test_bit(HIF_HOLDER, &gh->gh_iflags))
354 if (may_grant(gl, gh)) {
355 if (gh->gh_list.prev == &gl->gl_holders &&
357 spin_unlock(&gl->gl_lockref.lock);
358 /* FIXME: eliminate this eventually */
359 ret = glops->go_lock(gh);
360 spin_lock(&gl->gl_lockref.lock);
365 list_del_init(&gh->gh_list);
366 trace_gfs2_glock_queue(gh, 0);
367 gfs2_holder_wake(gh);
370 set_bit(HIF_HOLDER, &gh->gh_iflags);
371 trace_gfs2_promote(gh, 1);
372 gfs2_holder_wake(gh);
375 set_bit(HIF_HOLDER, &gh->gh_iflags);
376 trace_gfs2_promote(gh, 0);
377 gfs2_holder_wake(gh);
380 if (gh->gh_list.prev == &gl->gl_holders)
389 * find_first_waiter - find the first gh that's waiting for the glock
393 static inline struct gfs2_holder *find_first_waiter(const struct gfs2_glock *gl)
395 struct gfs2_holder *gh;
397 list_for_each_entry(gh, &gl->gl_holders, gh_list) {
398 if (!test_bit(HIF_HOLDER, &gh->gh_iflags))
405 * state_change - record that the glock is now in a different state
407 * @new_state the new state
411 static void state_change(struct gfs2_glock *gl, unsigned int new_state)
415 held1 = (gl->gl_state != LM_ST_UNLOCKED);
416 held2 = (new_state != LM_ST_UNLOCKED);
418 if (held1 != held2) {
419 GLOCK_BUG_ON(gl, __lockref_is_dead(&gl->gl_lockref));
421 gl->gl_lockref.count++;
423 gl->gl_lockref.count--;
425 if (held1 && held2 && list_empty(&gl->gl_holders))
426 clear_bit(GLF_QUEUED, &gl->gl_flags);
428 if (new_state != gl->gl_target)
429 /* shorten our minimum hold time */
430 gl->gl_hold_time = max(gl->gl_hold_time - GL_GLOCK_HOLD_DECR,
432 gl->gl_state = new_state;
433 gl->gl_tchange = jiffies;
436 static void gfs2_demote_wake(struct gfs2_glock *gl)
438 gl->gl_demote_state = LM_ST_EXCLUSIVE;
439 clear_bit(GLF_DEMOTE, &gl->gl_flags);
440 smp_mb__after_atomic();
441 wake_up_bit(&gl->gl_flags, GLF_DEMOTE);
445 * finish_xmote - The DLM has replied to one of our lock requests
447 * @ret: The status from the DLM
451 static void finish_xmote(struct gfs2_glock *gl, unsigned int ret)
453 const struct gfs2_glock_operations *glops = gl->gl_ops;
454 struct gfs2_holder *gh;
455 unsigned state = ret & LM_OUT_ST_MASK;
458 spin_lock(&gl->gl_lockref.lock);
459 trace_gfs2_glock_state_change(gl, state);
460 state_change(gl, state);
461 gh = find_first_waiter(gl);
463 /* Demote to UN request arrived during demote to SH or DF */
464 if (test_bit(GLF_DEMOTE_IN_PROGRESS, &gl->gl_flags) &&
465 state != LM_ST_UNLOCKED && gl->gl_demote_state == LM_ST_UNLOCKED)
466 gl->gl_target = LM_ST_UNLOCKED;
468 /* Check for state != intended state */
469 if (unlikely(state != gl->gl_target)) {
470 if (gh && !test_bit(GLF_DEMOTE_IN_PROGRESS, &gl->gl_flags)) {
471 /* move to back of queue and try next entry */
472 if (ret & LM_OUT_CANCELED) {
473 if ((gh->gh_flags & LM_FLAG_PRIORITY) == 0)
474 list_move_tail(&gh->gh_list, &gl->gl_holders);
475 gh = find_first_waiter(gl);
476 gl->gl_target = gh->gh_state;
479 /* Some error or failed "try lock" - report it */
480 if ((ret & LM_OUT_ERROR) ||
481 (gh->gh_flags & (LM_FLAG_TRY | LM_FLAG_TRY_1CB))) {
482 gl->gl_target = gl->gl_state;
488 /* Unlocked due to conversion deadlock, try again */
491 do_xmote(gl, gh, gl->gl_target);
493 /* Conversion fails, unlock and try again */
496 do_xmote(gl, gh, LM_ST_UNLOCKED);
498 default: /* Everything else */
499 fs_err(gl->gl_name.ln_sbd, "wanted %u got %u\n",
500 gl->gl_target, state);
503 spin_unlock(&gl->gl_lockref.lock);
507 /* Fast path - we got what we asked for */
508 if (test_and_clear_bit(GLF_DEMOTE_IN_PROGRESS, &gl->gl_flags))
509 gfs2_demote_wake(gl);
510 if (state != LM_ST_UNLOCKED) {
511 if (glops->go_xmote_bh) {
512 spin_unlock(&gl->gl_lockref.lock);
513 rv = glops->go_xmote_bh(gl, gh);
514 spin_lock(&gl->gl_lockref.lock);
525 clear_bit(GLF_LOCK, &gl->gl_flags);
527 spin_unlock(&gl->gl_lockref.lock);
531 * do_xmote - Calls the DLM to change the state of a lock
532 * @gl: The lock state
533 * @gh: The holder (only for promotes)
534 * @target: The target lock state
538 static void do_xmote(struct gfs2_glock *gl, struct gfs2_holder *gh, unsigned int target)
539 __releases(&gl->gl_lockref.lock)
540 __acquires(&gl->gl_lockref.lock)
542 const struct gfs2_glock_operations *glops = gl->gl_ops;
543 struct gfs2_sbd *sdp = gl->gl_name.ln_sbd;
544 unsigned int lck_flags = (unsigned int)(gh ? gh->gh_flags : 0);
547 if (unlikely(test_bit(SDF_WITHDRAWN, &sdp->sd_flags)) &&
548 target != LM_ST_UNLOCKED)
550 lck_flags &= (LM_FLAG_TRY | LM_FLAG_TRY_1CB | LM_FLAG_NOEXP |
552 GLOCK_BUG_ON(gl, gl->gl_state == target);
553 GLOCK_BUG_ON(gl, gl->gl_state == gl->gl_target);
554 if ((target == LM_ST_UNLOCKED || target == LM_ST_DEFERRED) &&
556 set_bit(GLF_INVALIDATE_IN_PROGRESS, &gl->gl_flags);
557 do_error(gl, 0); /* Fail queued try locks */
560 set_bit(GLF_BLOCKING, &gl->gl_flags);
561 if ((gl->gl_req == LM_ST_UNLOCKED) ||
562 (gl->gl_state == LM_ST_EXCLUSIVE) ||
563 (lck_flags & (LM_FLAG_TRY|LM_FLAG_TRY_1CB)))
564 clear_bit(GLF_BLOCKING, &gl->gl_flags);
565 spin_unlock(&gl->gl_lockref.lock);
568 if (test_bit(GLF_INVALIDATE_IN_PROGRESS, &gl->gl_flags))
569 glops->go_inval(gl, target == LM_ST_DEFERRED ? 0 : DIO_METADATA);
570 clear_bit(GLF_INVALIDATE_IN_PROGRESS, &gl->gl_flags);
573 if (sdp->sd_lockstruct.ls_ops->lm_lock) {
575 ret = sdp->sd_lockstruct.ls_ops->lm_lock(gl, target, lck_flags);
576 if (ret == -EINVAL && gl->gl_target == LM_ST_UNLOCKED &&
577 target == LM_ST_UNLOCKED &&
578 test_bit(SDF_SKIP_DLM_UNLOCK, &sdp->sd_flags)) {
579 finish_xmote(gl, target);
580 gfs2_glock_queue_work(gl, 0);
583 fs_err(sdp, "lm_lock ret %d\n", ret);
584 GLOCK_BUG_ON(gl, !test_bit(SDF_WITHDRAWN,
587 } else { /* lock_nolock */
588 finish_xmote(gl, target);
589 gfs2_glock_queue_work(gl, 0);
592 spin_lock(&gl->gl_lockref.lock);
596 * find_first_holder - find the first "holder" gh
600 static inline struct gfs2_holder *find_first_holder(const struct gfs2_glock *gl)
602 struct gfs2_holder *gh;
604 if (!list_empty(&gl->gl_holders)) {
605 gh = list_entry(gl->gl_holders.next, struct gfs2_holder, gh_list);
606 if (test_bit(HIF_HOLDER, &gh->gh_iflags))
613 * run_queue - do all outstanding tasks related to a glock
614 * @gl: The glock in question
615 * @nonblock: True if we must not block in run_queue
619 static void run_queue(struct gfs2_glock *gl, const int nonblock)
620 __releases(&gl->gl_lockref.lock)
621 __acquires(&gl->gl_lockref.lock)
623 struct gfs2_holder *gh = NULL;
626 if (test_and_set_bit(GLF_LOCK, &gl->gl_flags))
629 GLOCK_BUG_ON(gl, test_bit(GLF_DEMOTE_IN_PROGRESS, &gl->gl_flags));
631 if (test_bit(GLF_DEMOTE, &gl->gl_flags) &&
632 gl->gl_demote_state != gl->gl_state) {
633 if (find_first_holder(gl))
637 set_bit(GLF_DEMOTE_IN_PROGRESS, &gl->gl_flags);
638 GLOCK_BUG_ON(gl, gl->gl_demote_state == LM_ST_EXCLUSIVE);
639 gl->gl_target = gl->gl_demote_state;
641 if (test_bit(GLF_DEMOTE, &gl->gl_flags))
642 gfs2_demote_wake(gl);
643 ret = do_promote(gl);
648 gh = find_first_waiter(gl);
649 gl->gl_target = gh->gh_state;
650 if (!(gh->gh_flags & (LM_FLAG_TRY | LM_FLAG_TRY_1CB)))
651 do_error(gl, 0); /* Fail queued try locks */
653 do_xmote(gl, gh, gl->gl_target);
658 clear_bit(GLF_LOCK, &gl->gl_flags);
659 smp_mb__after_atomic();
660 gl->gl_lockref.count++;
661 __gfs2_glock_queue_work(gl, 0);
665 clear_bit(GLF_LOCK, &gl->gl_flags);
666 smp_mb__after_atomic();
670 static void delete_work_func(struct work_struct *work)
672 struct gfs2_glock *gl = container_of(work, struct gfs2_glock, gl_delete);
673 struct gfs2_sbd *sdp = gl->gl_name.ln_sbd;
675 u64 no_addr = gl->gl_name.ln_number;
677 /* If someone's using this glock to create a new dinode, the block must
678 have been freed by another node, then re-used, in which case our
679 iopen callback is too late after the fact. Ignore it. */
680 if (test_bit(GLF_INODE_CREATING, &gl->gl_flags))
683 inode = gfs2_lookup_by_inum(sdp, no_addr, NULL, GFS2_BLKST_UNLINKED);
684 if (!IS_ERR_OR_NULL(inode)) {
685 d_prune_aliases(inode);
692 static void glock_work_func(struct work_struct *work)
694 unsigned long delay = 0;
695 struct gfs2_glock *gl = container_of(work, struct gfs2_glock, gl_work.work);
696 unsigned int drop_refs = 1;
698 if (test_and_clear_bit(GLF_REPLY_PENDING, &gl->gl_flags)) {
699 finish_xmote(gl, gl->gl_reply);
702 spin_lock(&gl->gl_lockref.lock);
703 if (test_bit(GLF_PENDING_DEMOTE, &gl->gl_flags) &&
704 gl->gl_state != LM_ST_UNLOCKED &&
705 gl->gl_demote_state != LM_ST_EXCLUSIVE) {
706 unsigned long holdtime, now = jiffies;
708 holdtime = gl->gl_tchange + gl->gl_hold_time;
709 if (time_before(now, holdtime))
710 delay = holdtime - now;
713 clear_bit(GLF_PENDING_DEMOTE, &gl->gl_flags);
714 set_bit(GLF_DEMOTE, &gl->gl_flags);
719 /* Keep one glock reference for the work we requeue. */
721 if (gl->gl_name.ln_type != LM_TYPE_INODE)
723 __gfs2_glock_queue_work(gl, delay);
727 * Drop the remaining glock references manually here. (Mind that
728 * __gfs2_glock_queue_work depends on the lockref spinlock begin held
731 gl->gl_lockref.count -= drop_refs;
732 if (!gl->gl_lockref.count) {
733 __gfs2_glock_put(gl);
736 spin_unlock(&gl->gl_lockref.lock);
739 static struct gfs2_glock *find_insert_glock(struct lm_lockname *name,
740 struct gfs2_glock *new)
742 struct wait_glock_queue wait;
743 wait_queue_head_t *wq = glock_waitqueue(name);
744 struct gfs2_glock *gl;
747 init_wait(&wait.wait);
748 wait.wait.func = glock_wake_function;
751 prepare_to_wait(wq, &wait.wait, TASK_UNINTERRUPTIBLE);
754 gl = rhashtable_lookup_get_insert_fast(&gl_hash_table,
755 &new->gl_node, ht_parms);
759 gl = rhashtable_lookup_fast(&gl_hash_table,
762 if (gl && !lockref_get_not_dead(&gl->gl_lockref)) {
769 finish_wait(wq, &wait.wait);
774 * gfs2_glock_get() - Get a glock, or create one if one doesn't exist
775 * @sdp: The GFS2 superblock
776 * @number: the lock number
777 * @glops: The glock_operations to use
778 * @create: If 0, don't create the glock if it doesn't exist
779 * @glp: the glock is returned here
781 * This does not lock a glock, just finds/creates structures for one.
786 int gfs2_glock_get(struct gfs2_sbd *sdp, u64 number,
787 const struct gfs2_glock_operations *glops, int create,
788 struct gfs2_glock **glp)
790 struct super_block *s = sdp->sd_vfs;
791 struct lm_lockname name = { .ln_number = number,
792 .ln_type = glops->go_type,
794 struct gfs2_glock *gl, *tmp;
795 struct address_space *mapping;
796 struct kmem_cache *cachep;
799 gl = find_insert_glock(&name, NULL);
807 if (glops->go_flags & GLOF_ASPACE)
808 cachep = gfs2_glock_aspace_cachep;
810 cachep = gfs2_glock_cachep;
811 gl = kmem_cache_alloc(cachep, GFP_NOFS);
815 memset(&gl->gl_lksb, 0, sizeof(struct dlm_lksb));
817 if (glops->go_flags & GLOF_LVB) {
818 gl->gl_lksb.sb_lvbptr = kzalloc(GFS2_MIN_LVB_SIZE, GFP_NOFS);
819 if (!gl->gl_lksb.sb_lvbptr) {
820 kmem_cache_free(cachep, gl);
825 atomic_inc(&sdp->sd_glock_disposal);
826 gl->gl_node.next = NULL;
829 gl->gl_lockref.count = 1;
830 gl->gl_state = LM_ST_UNLOCKED;
831 gl->gl_target = LM_ST_UNLOCKED;
832 gl->gl_demote_state = LM_ST_EXCLUSIVE;
836 /* We use the global stats to estimate the initial per-glock stats */
837 gl->gl_stats = this_cpu_ptr(sdp->sd_lkstats)->lkstats[glops->go_type];
839 gl->gl_stats.stats[GFS2_LKS_DCOUNT] = 0;
840 gl->gl_stats.stats[GFS2_LKS_QCOUNT] = 0;
841 gl->gl_tchange = jiffies;
842 gl->gl_object = NULL;
843 gl->gl_hold_time = GL_GLOCK_DFT_HOLD;
844 INIT_DELAYED_WORK(&gl->gl_work, glock_work_func);
845 INIT_WORK(&gl->gl_delete, delete_work_func);
847 mapping = gfs2_glock2aspace(gl);
849 mapping->a_ops = &gfs2_meta_aops;
850 mapping->host = s->s_bdev->bd_inode;
852 mapping_set_gfp_mask(mapping, GFP_NOFS);
853 mapping->private_data = NULL;
854 mapping->writeback_index = 0;
857 tmp = find_insert_glock(&name, gl);
869 kfree(gl->gl_lksb.sb_lvbptr);
870 kmem_cache_free(cachep, gl);
871 atomic_dec(&sdp->sd_glock_disposal);
878 * gfs2_holder_init - initialize a struct gfs2_holder in the default way
880 * @state: the state we're requesting
881 * @flags: the modifier flags
882 * @gh: the holder structure
886 void gfs2_holder_init(struct gfs2_glock *gl, unsigned int state, u16 flags,
887 struct gfs2_holder *gh)
889 INIT_LIST_HEAD(&gh->gh_list);
891 gh->gh_ip = _RET_IP_;
892 gh->gh_owner_pid = get_pid(task_pid(current));
893 gh->gh_state = state;
894 gh->gh_flags = flags;
901 * gfs2_holder_reinit - reinitialize a struct gfs2_holder so we can requeue it
902 * @state: the state we're requesting
903 * @flags: the modifier flags
904 * @gh: the holder structure
906 * Don't mess with the glock.
910 void gfs2_holder_reinit(unsigned int state, u16 flags, struct gfs2_holder *gh)
912 gh->gh_state = state;
913 gh->gh_flags = flags;
915 gh->gh_ip = _RET_IP_;
916 put_pid(gh->gh_owner_pid);
917 gh->gh_owner_pid = get_pid(task_pid(current));
921 * gfs2_holder_uninit - uninitialize a holder structure (drop glock reference)
922 * @gh: the holder structure
926 void gfs2_holder_uninit(struct gfs2_holder *gh)
928 put_pid(gh->gh_owner_pid);
929 gfs2_glock_put(gh->gh_gl);
930 gfs2_holder_mark_uninitialized(gh);
935 * gfs2_glock_wait - wait on a glock acquisition
936 * @gh: the glock holder
938 * Returns: 0 on success
941 int gfs2_glock_wait(struct gfs2_holder *gh)
943 unsigned long time1 = jiffies;
946 wait_on_bit(&gh->gh_iflags, HIF_WAIT, TASK_UNINTERRUPTIBLE);
947 if (time_after(jiffies, time1 + HZ)) /* have we waited > a second? */
948 /* Lengthen the minimum hold time. */
949 gh->gh_gl->gl_hold_time = min(gh->gh_gl->gl_hold_time +
956 * handle_callback - process a demote request
958 * @state: the state the caller wants us to change to
960 * There are only two requests that we are going to see in actual
961 * practise: LM_ST_SHARED and LM_ST_UNLOCKED
964 static void handle_callback(struct gfs2_glock *gl, unsigned int state,
965 unsigned long delay, bool remote)
967 int bit = delay ? GLF_PENDING_DEMOTE : GLF_DEMOTE;
969 set_bit(bit, &gl->gl_flags);
970 if (gl->gl_demote_state == LM_ST_EXCLUSIVE) {
971 gl->gl_demote_state = state;
972 gl->gl_demote_time = jiffies;
973 } else if (gl->gl_demote_state != LM_ST_UNLOCKED &&
974 gl->gl_demote_state != state) {
975 gl->gl_demote_state = LM_ST_UNLOCKED;
977 if (gl->gl_ops->go_callback)
978 gl->gl_ops->go_callback(gl, remote);
979 trace_gfs2_demote_rq(gl, remote);
982 void gfs2_print_dbg(struct seq_file *seq, const char *fmt, ...)
984 struct va_format vaf;
990 seq_vprintf(seq, fmt, args);
1002 * add_to_queue - Add a holder to the wait queue (but look for recursion)
1003 * @gh: the holder structure to add
1005 * Eventually we should move the recursive locking trap to a
1006 * debugging option or something like that. This is the fast
1007 * path and needs to have the minimum number of distractions.
1011 static inline void add_to_queue(struct gfs2_holder *gh)
1012 __releases(&gl->gl_lockref.lock)
1013 __acquires(&gl->gl_lockref.lock)
1015 struct gfs2_glock *gl = gh->gh_gl;
1016 struct gfs2_sbd *sdp = gl->gl_name.ln_sbd;
1017 struct list_head *insert_pt = NULL;
1018 struct gfs2_holder *gh2;
1021 BUG_ON(gh->gh_owner_pid == NULL);
1022 if (test_and_set_bit(HIF_WAIT, &gh->gh_iflags))
1025 if (gh->gh_flags & (LM_FLAG_TRY | LM_FLAG_TRY_1CB)) {
1026 if (test_bit(GLF_LOCK, &gl->gl_flags))
1027 try_futile = !may_grant(gl, gh);
1028 if (test_bit(GLF_INVALIDATE_IN_PROGRESS, &gl->gl_flags))
1032 list_for_each_entry(gh2, &gl->gl_holders, gh_list) {
1033 if (unlikely(gh2->gh_owner_pid == gh->gh_owner_pid &&
1034 (gh->gh_gl->gl_ops->go_type != LM_TYPE_FLOCK)))
1035 goto trap_recursive;
1037 !(gh2->gh_flags & (LM_FLAG_TRY | LM_FLAG_TRY_1CB))) {
1039 gh->gh_error = GLR_TRYFAILED;
1040 gfs2_holder_wake(gh);
1043 if (test_bit(HIF_HOLDER, &gh2->gh_iflags))
1045 if (unlikely((gh->gh_flags & LM_FLAG_PRIORITY) && !insert_pt))
1046 insert_pt = &gh2->gh_list;
1048 set_bit(GLF_QUEUED, &gl->gl_flags);
1049 trace_gfs2_glock_queue(gh, 1);
1050 gfs2_glstats_inc(gl, GFS2_LKS_QCOUNT);
1051 gfs2_sbstats_inc(gl, GFS2_LKS_QCOUNT);
1052 if (likely(insert_pt == NULL)) {
1053 list_add_tail(&gh->gh_list, &gl->gl_holders);
1054 if (unlikely(gh->gh_flags & LM_FLAG_PRIORITY))
1058 list_add_tail(&gh->gh_list, insert_pt);
1060 gh = list_entry(gl->gl_holders.next, struct gfs2_holder, gh_list);
1061 if (!(gh->gh_flags & LM_FLAG_PRIORITY)) {
1062 spin_unlock(&gl->gl_lockref.lock);
1063 if (sdp->sd_lockstruct.ls_ops->lm_cancel)
1064 sdp->sd_lockstruct.ls_ops->lm_cancel(gl);
1065 spin_lock(&gl->gl_lockref.lock);
1070 fs_err(sdp, "original: %pSR\n", (void *)gh2->gh_ip);
1071 fs_err(sdp, "pid: %d\n", pid_nr(gh2->gh_owner_pid));
1072 fs_err(sdp, "lock type: %d req lock state : %d\n",
1073 gh2->gh_gl->gl_name.ln_type, gh2->gh_state);
1074 fs_err(sdp, "new: %pSR\n", (void *)gh->gh_ip);
1075 fs_err(sdp, "pid: %d\n", pid_nr(gh->gh_owner_pid));
1076 fs_err(sdp, "lock type: %d req lock state : %d\n",
1077 gh->gh_gl->gl_name.ln_type, gh->gh_state);
1078 gfs2_dump_glock(NULL, gl, true);
1083 * gfs2_glock_nq - enqueue a struct gfs2_holder onto a glock (acquire a glock)
1084 * @gh: the holder structure
1086 * if (gh->gh_flags & GL_ASYNC), this never returns an error
1088 * Returns: 0, GLR_TRYFAILED, or errno on failure
1091 int gfs2_glock_nq(struct gfs2_holder *gh)
1093 struct gfs2_glock *gl = gh->gh_gl;
1094 struct gfs2_sbd *sdp = gl->gl_name.ln_sbd;
1097 if (unlikely(test_bit(SDF_WITHDRAWN, &sdp->sd_flags)))
1100 if (test_bit(GLF_LRU, &gl->gl_flags))
1101 gfs2_glock_remove_from_lru(gl);
1103 spin_lock(&gl->gl_lockref.lock);
1105 if (unlikely((LM_FLAG_NOEXP & gh->gh_flags) &&
1106 test_and_clear_bit(GLF_FROZEN, &gl->gl_flags))) {
1107 set_bit(GLF_REPLY_PENDING, &gl->gl_flags);
1108 gl->gl_lockref.count++;
1109 __gfs2_glock_queue_work(gl, 0);
1112 spin_unlock(&gl->gl_lockref.lock);
1114 if (!(gh->gh_flags & GL_ASYNC))
1115 error = gfs2_glock_wait(gh);
1121 * gfs2_glock_poll - poll to see if an async request has been completed
1124 * Returns: 1 if the request is ready to be gfs2_glock_wait()ed on
1127 int gfs2_glock_poll(struct gfs2_holder *gh)
1129 return test_bit(HIF_WAIT, &gh->gh_iflags) ? 0 : 1;
1133 * gfs2_glock_dq - dequeue a struct gfs2_holder from a glock (release a glock)
1134 * @gh: the glock holder
1138 void gfs2_glock_dq(struct gfs2_holder *gh)
1140 struct gfs2_glock *gl = gh->gh_gl;
1141 const struct gfs2_glock_operations *glops = gl->gl_ops;
1145 spin_lock(&gl->gl_lockref.lock);
1146 if (gh->gh_flags & GL_NOCACHE)
1147 handle_callback(gl, LM_ST_UNLOCKED, 0, false);
1149 list_del_init(&gh->gh_list);
1150 clear_bit(HIF_HOLDER, &gh->gh_iflags);
1151 if (find_first_holder(gl) == NULL) {
1152 if (glops->go_unlock) {
1153 GLOCK_BUG_ON(gl, test_and_set_bit(GLF_LOCK, &gl->gl_flags));
1154 spin_unlock(&gl->gl_lockref.lock);
1155 glops->go_unlock(gh);
1156 spin_lock(&gl->gl_lockref.lock);
1157 clear_bit(GLF_LOCK, &gl->gl_flags);
1159 if (list_empty(&gl->gl_holders) &&
1160 !test_bit(GLF_PENDING_DEMOTE, &gl->gl_flags) &&
1161 !test_bit(GLF_DEMOTE, &gl->gl_flags))
1164 if (!test_bit(GLF_LFLUSH, &gl->gl_flags) && demote_ok(gl))
1165 gfs2_glock_add_to_lru(gl);
1167 trace_gfs2_glock_queue(gh, 0);
1168 if (unlikely(!fast_path)) {
1169 gl->gl_lockref.count++;
1170 if (test_bit(GLF_PENDING_DEMOTE, &gl->gl_flags) &&
1171 !test_bit(GLF_DEMOTE, &gl->gl_flags) &&
1172 gl->gl_name.ln_type == LM_TYPE_INODE)
1173 delay = gl->gl_hold_time;
1174 __gfs2_glock_queue_work(gl, delay);
1176 spin_unlock(&gl->gl_lockref.lock);
1179 void gfs2_glock_dq_wait(struct gfs2_holder *gh)
1181 struct gfs2_glock *gl = gh->gh_gl;
1184 wait_on_bit(&gl->gl_flags, GLF_DEMOTE, TASK_UNINTERRUPTIBLE);
1188 * gfs2_glock_dq_uninit - dequeue a holder from a glock and initialize it
1189 * @gh: the holder structure
1193 void gfs2_glock_dq_uninit(struct gfs2_holder *gh)
1196 gfs2_holder_uninit(gh);
1200 * gfs2_glock_nq_num - acquire a glock based on lock number
1201 * @sdp: the filesystem
1202 * @number: the lock number
1203 * @glops: the glock operations for the type of glock
1204 * @state: the state to acquire the glock in
1205 * @flags: modifier flags for the acquisition
1206 * @gh: the struct gfs2_holder
1211 int gfs2_glock_nq_num(struct gfs2_sbd *sdp, u64 number,
1212 const struct gfs2_glock_operations *glops,
1213 unsigned int state, u16 flags, struct gfs2_holder *gh)
1215 struct gfs2_glock *gl;
1218 error = gfs2_glock_get(sdp, number, glops, CREATE, &gl);
1220 error = gfs2_glock_nq_init(gl, state, flags, gh);
1228 * glock_compare - Compare two struct gfs2_glock structures for sorting
1229 * @arg_a: the first structure
1230 * @arg_b: the second structure
1234 static int glock_compare(const void *arg_a, const void *arg_b)
1236 const struct gfs2_holder *gh_a = *(const struct gfs2_holder **)arg_a;
1237 const struct gfs2_holder *gh_b = *(const struct gfs2_holder **)arg_b;
1238 const struct lm_lockname *a = &gh_a->gh_gl->gl_name;
1239 const struct lm_lockname *b = &gh_b->gh_gl->gl_name;
1241 if (a->ln_number > b->ln_number)
1243 if (a->ln_number < b->ln_number)
1245 BUG_ON(gh_a->gh_gl->gl_ops->go_type == gh_b->gh_gl->gl_ops->go_type);
1250 * nq_m_sync - synchonously acquire more than one glock in deadlock free order
1251 * @num_gh: the number of structures
1252 * @ghs: an array of struct gfs2_holder structures
1254 * Returns: 0 on success (all glocks acquired),
1255 * errno on failure (no glocks acquired)
1258 static int nq_m_sync(unsigned int num_gh, struct gfs2_holder *ghs,
1259 struct gfs2_holder **p)
1264 for (x = 0; x < num_gh; x++)
1267 sort(p, num_gh, sizeof(struct gfs2_holder *), glock_compare, NULL);
1269 for (x = 0; x < num_gh; x++) {
1270 p[x]->gh_flags &= ~(LM_FLAG_TRY | GL_ASYNC);
1272 error = gfs2_glock_nq(p[x]);
1275 gfs2_glock_dq(p[x]);
1284 * gfs2_glock_nq_m - acquire multiple glocks
1285 * @num_gh: the number of structures
1286 * @ghs: an array of struct gfs2_holder structures
1289 * Returns: 0 on success (all glocks acquired),
1290 * errno on failure (no glocks acquired)
1293 int gfs2_glock_nq_m(unsigned int num_gh, struct gfs2_holder *ghs)
1295 struct gfs2_holder *tmp[4];
1296 struct gfs2_holder **pph = tmp;
1303 ghs->gh_flags &= ~(LM_FLAG_TRY | GL_ASYNC);
1304 return gfs2_glock_nq(ghs);
1308 pph = kmalloc_array(num_gh, sizeof(struct gfs2_holder *),
1314 error = nq_m_sync(num_gh, ghs, pph);
1323 * gfs2_glock_dq_m - release multiple glocks
1324 * @num_gh: the number of structures
1325 * @ghs: an array of struct gfs2_holder structures
1329 void gfs2_glock_dq_m(unsigned int num_gh, struct gfs2_holder *ghs)
1332 gfs2_glock_dq(&ghs[num_gh]);
1335 void gfs2_glock_cb(struct gfs2_glock *gl, unsigned int state)
1337 unsigned long delay = 0;
1338 unsigned long holdtime;
1339 unsigned long now = jiffies;
1341 gfs2_glock_hold(gl);
1342 holdtime = gl->gl_tchange + gl->gl_hold_time;
1343 if (test_bit(GLF_QUEUED, &gl->gl_flags) &&
1344 gl->gl_name.ln_type == LM_TYPE_INODE) {
1345 if (time_before(now, holdtime))
1346 delay = holdtime - now;
1347 if (test_bit(GLF_REPLY_PENDING, &gl->gl_flags))
1348 delay = gl->gl_hold_time;
1351 spin_lock(&gl->gl_lockref.lock);
1352 handle_callback(gl, state, delay, true);
1353 __gfs2_glock_queue_work(gl, delay);
1354 spin_unlock(&gl->gl_lockref.lock);
1358 * gfs2_should_freeze - Figure out if glock should be frozen
1359 * @gl: The glock in question
1361 * Glocks are not frozen if (a) the result of the dlm operation is
1362 * an error, (b) the locking operation was an unlock operation or
1363 * (c) if there is a "noexp" flagged request anywhere in the queue
1365 * Returns: 1 if freezing should occur, 0 otherwise
1368 static int gfs2_should_freeze(const struct gfs2_glock *gl)
1370 const struct gfs2_holder *gh;
1372 if (gl->gl_reply & ~LM_OUT_ST_MASK)
1374 if (gl->gl_target == LM_ST_UNLOCKED)
1377 list_for_each_entry(gh, &gl->gl_holders, gh_list) {
1378 if (test_bit(HIF_HOLDER, &gh->gh_iflags))
1380 if (LM_FLAG_NOEXP & gh->gh_flags)
1388 * gfs2_glock_complete - Callback used by locking
1389 * @gl: Pointer to the glock
1390 * @ret: The return value from the dlm
1392 * The gl_reply field is under the gl_lockref.lock lock so that it is ok
1393 * to use a bitfield shared with other glock state fields.
1396 void gfs2_glock_complete(struct gfs2_glock *gl, int ret)
1398 struct lm_lockstruct *ls = &gl->gl_name.ln_sbd->sd_lockstruct;
1400 spin_lock(&gl->gl_lockref.lock);
1403 if (unlikely(test_bit(DFL_BLOCK_LOCKS, &ls->ls_recover_flags))) {
1404 if (gfs2_should_freeze(gl)) {
1405 set_bit(GLF_FROZEN, &gl->gl_flags);
1406 spin_unlock(&gl->gl_lockref.lock);
1411 gl->gl_lockref.count++;
1412 set_bit(GLF_REPLY_PENDING, &gl->gl_flags);
1413 __gfs2_glock_queue_work(gl, 0);
1414 spin_unlock(&gl->gl_lockref.lock);
1417 static int glock_cmp(void *priv, struct list_head *a, struct list_head *b)
1419 struct gfs2_glock *gla, *glb;
1421 gla = list_entry(a, struct gfs2_glock, gl_lru);
1422 glb = list_entry(b, struct gfs2_glock, gl_lru);
1424 if (gla->gl_name.ln_number > glb->gl_name.ln_number)
1426 if (gla->gl_name.ln_number < glb->gl_name.ln_number)
1433 * gfs2_dispose_glock_lru - Demote a list of glocks
1434 * @list: The list to dispose of
1436 * Disposing of glocks may involve disk accesses, so that here we sort
1437 * the glocks by number (i.e. disk location of the inodes) so that if
1438 * there are any such accesses, they'll be sent in order (mostly).
1440 * Must be called under the lru_lock, but may drop and retake this
1441 * lock. While the lru_lock is dropped, entries may vanish from the
1442 * list, but no new entries will appear on the list (since it is
1446 static void gfs2_dispose_glock_lru(struct list_head *list)
1447 __releases(&lru_lock)
1448 __acquires(&lru_lock)
1450 struct gfs2_glock *gl;
1452 list_sort(NULL, list, glock_cmp);
1454 while(!list_empty(list)) {
1455 gl = list_entry(list->next, struct gfs2_glock, gl_lru);
1456 list_del_init(&gl->gl_lru);
1457 if (!spin_trylock(&gl->gl_lockref.lock)) {
1459 list_add(&gl->gl_lru, &lru_list);
1460 set_bit(GLF_LRU, &gl->gl_flags);
1461 atomic_inc(&lru_count);
1464 if (test_and_set_bit(GLF_LOCK, &gl->gl_flags)) {
1465 spin_unlock(&gl->gl_lockref.lock);
1466 goto add_back_to_lru;
1468 gl->gl_lockref.count++;
1470 handle_callback(gl, LM_ST_UNLOCKED, 0, false);
1471 WARN_ON(!test_and_clear_bit(GLF_LOCK, &gl->gl_flags));
1472 __gfs2_glock_queue_work(gl, 0);
1473 spin_unlock(&gl->gl_lockref.lock);
1474 cond_resched_lock(&lru_lock);
1479 * gfs2_scan_glock_lru - Scan the LRU looking for locks to demote
1480 * @nr: The number of entries to scan
1482 * This function selects the entries on the LRU which are able to
1483 * be demoted, and then kicks off the process by calling
1484 * gfs2_dispose_glock_lru() above.
1487 static long gfs2_scan_glock_lru(int nr)
1489 struct gfs2_glock *gl;
1494 spin_lock(&lru_lock);
1495 while ((nr-- >= 0) && !list_empty(&lru_list)) {
1496 gl = list_entry(lru_list.next, struct gfs2_glock, gl_lru);
1498 /* Test for being demotable */
1499 if (!test_bit(GLF_LOCK, &gl->gl_flags)) {
1500 list_move(&gl->gl_lru, &dispose);
1501 atomic_dec(&lru_count);
1502 clear_bit(GLF_LRU, &gl->gl_flags);
1507 list_move(&gl->gl_lru, &skipped);
1509 list_splice(&skipped, &lru_list);
1510 if (!list_empty(&dispose))
1511 gfs2_dispose_glock_lru(&dispose);
1512 spin_unlock(&lru_lock);
1517 static unsigned long gfs2_glock_shrink_scan(struct shrinker *shrink,
1518 struct shrink_control *sc)
1520 if (!(sc->gfp_mask & __GFP_FS))
1522 return gfs2_scan_glock_lru(sc->nr_to_scan);
1525 static unsigned long gfs2_glock_shrink_count(struct shrinker *shrink,
1526 struct shrink_control *sc)
1528 return vfs_pressure_ratio(atomic_read(&lru_count));
1531 static struct shrinker glock_shrinker = {
1532 .seeks = DEFAULT_SEEKS,
1533 .count_objects = gfs2_glock_shrink_count,
1534 .scan_objects = gfs2_glock_shrink_scan,
1538 * examine_bucket - Call a function for glock in a hash bucket
1539 * @examiner: the function
1540 * @sdp: the filesystem
1541 * @bucket: the bucket
1543 * Note that the function can be called multiple times on the same
1544 * object. So the user must ensure that the function can cope with
1548 static void glock_hash_walk(glock_examiner examiner, const struct gfs2_sbd *sdp)
1550 struct gfs2_glock *gl;
1551 struct rhashtable_iter iter;
1553 rhashtable_walk_enter(&gl_hash_table, &iter);
1556 rhashtable_walk_start(&iter);
1558 while ((gl = rhashtable_walk_next(&iter)) && !IS_ERR(gl))
1559 if (gl->gl_name.ln_sbd == sdp &&
1560 lockref_get_not_dead(&gl->gl_lockref))
1563 rhashtable_walk_stop(&iter);
1564 } while (cond_resched(), gl == ERR_PTR(-EAGAIN));
1566 rhashtable_walk_exit(&iter);
1570 * thaw_glock - thaw out a glock which has an unprocessed reply waiting
1571 * @gl: The glock to thaw
1575 static void thaw_glock(struct gfs2_glock *gl)
1577 if (!test_and_clear_bit(GLF_FROZEN, &gl->gl_flags)) {
1581 set_bit(GLF_REPLY_PENDING, &gl->gl_flags);
1582 gfs2_glock_queue_work(gl, 0);
1586 * clear_glock - look at a glock and see if we can free it from glock cache
1587 * @gl: the glock to look at
1591 static void clear_glock(struct gfs2_glock *gl)
1593 gfs2_glock_remove_from_lru(gl);
1595 spin_lock(&gl->gl_lockref.lock);
1596 if (gl->gl_state != LM_ST_UNLOCKED)
1597 handle_callback(gl, LM_ST_UNLOCKED, 0, false);
1598 __gfs2_glock_queue_work(gl, 0);
1599 spin_unlock(&gl->gl_lockref.lock);
1603 * gfs2_glock_thaw - Thaw any frozen glocks
1604 * @sdp: The super block
1608 void gfs2_glock_thaw(struct gfs2_sbd *sdp)
1610 glock_hash_walk(thaw_glock, sdp);
1613 static void dump_glock(struct seq_file *seq, struct gfs2_glock *gl, bool fsid)
1615 spin_lock(&gl->gl_lockref.lock);
1616 gfs2_dump_glock(seq, gl, fsid);
1617 spin_unlock(&gl->gl_lockref.lock);
1620 static void dump_glock_func(struct gfs2_glock *gl)
1622 dump_glock(NULL, gl, true);
1626 * gfs2_gl_hash_clear - Empty out the glock hash table
1627 * @sdp: the filesystem
1628 * @wait: wait until it's all gone
1630 * Called when unmounting the filesystem.
1633 void gfs2_gl_hash_clear(struct gfs2_sbd *sdp)
1635 set_bit(SDF_SKIP_DLM_UNLOCK, &sdp->sd_flags);
1636 flush_workqueue(glock_workqueue);
1637 glock_hash_walk(clear_glock, sdp);
1638 flush_workqueue(glock_workqueue);
1639 wait_event_timeout(sdp->sd_glock_wait,
1640 atomic_read(&sdp->sd_glock_disposal) == 0,
1642 glock_hash_walk(dump_glock_func, sdp);
1645 void gfs2_glock_finish_truncate(struct gfs2_inode *ip)
1647 struct gfs2_glock *gl = ip->i_gl;
1650 ret = gfs2_truncatei_resume(ip);
1651 gfs2_assert_withdraw(gl->gl_name.ln_sbd, ret == 0);
1653 spin_lock(&gl->gl_lockref.lock);
1654 clear_bit(GLF_LOCK, &gl->gl_flags);
1656 spin_unlock(&gl->gl_lockref.lock);
1659 static const char *state2str(unsigned state)
1662 case LM_ST_UNLOCKED:
1666 case LM_ST_DEFERRED:
1668 case LM_ST_EXCLUSIVE:
1674 static const char *hflags2str(char *buf, u16 flags, unsigned long iflags)
1677 if (flags & LM_FLAG_TRY)
1679 if (flags & LM_FLAG_TRY_1CB)
1681 if (flags & LM_FLAG_NOEXP)
1683 if (flags & LM_FLAG_ANY)
1685 if (flags & LM_FLAG_PRIORITY)
1687 if (flags & GL_ASYNC)
1689 if (flags & GL_EXACT)
1691 if (flags & GL_NOCACHE)
1693 if (test_bit(HIF_HOLDER, &iflags))
1695 if (test_bit(HIF_WAIT, &iflags))
1697 if (test_bit(HIF_FIRST, &iflags))
1704 * dump_holder - print information about a glock holder
1705 * @seq: the seq_file struct
1706 * @gh: the glock holder
1707 * @fs_id_buf: pointer to file system id (if requested)
1711 static void dump_holder(struct seq_file *seq, const struct gfs2_holder *gh,
1712 const char *fs_id_buf)
1714 struct task_struct *gh_owner = NULL;
1718 if (gh->gh_owner_pid)
1719 gh_owner = pid_task(gh->gh_owner_pid, PIDTYPE_PID);
1720 gfs2_print_dbg(seq, "%s H: s:%s f:%s e:%d p:%ld [%s] %pS\n",
1721 fs_id_buf, state2str(gh->gh_state),
1722 hflags2str(flags_buf, gh->gh_flags, gh->gh_iflags),
1724 gh->gh_owner_pid ? (long)pid_nr(gh->gh_owner_pid) : -1,
1725 gh_owner ? gh_owner->comm : "(ended)",
1730 static const char *gflags2str(char *buf, const struct gfs2_glock *gl)
1732 const unsigned long *gflags = &gl->gl_flags;
1735 if (test_bit(GLF_LOCK, gflags))
1737 if (test_bit(GLF_DEMOTE, gflags))
1739 if (test_bit(GLF_PENDING_DEMOTE, gflags))
1741 if (test_bit(GLF_DEMOTE_IN_PROGRESS, gflags))
1743 if (test_bit(GLF_DIRTY, gflags))
1745 if (test_bit(GLF_LFLUSH, gflags))
1747 if (test_bit(GLF_INVALIDATE_IN_PROGRESS, gflags))
1749 if (test_bit(GLF_REPLY_PENDING, gflags))
1751 if (test_bit(GLF_INITIAL, gflags))
1753 if (test_bit(GLF_FROZEN, gflags))
1755 if (test_bit(GLF_QUEUED, gflags))
1757 if (test_bit(GLF_LRU, gflags))
1761 if (test_bit(GLF_BLOCKING, gflags))
1768 * gfs2_dump_glock - print information about a glock
1769 * @seq: The seq_file struct
1771 * @fsid: If true, also dump the file system id
1773 * The file format is as follows:
1774 * One line per object, capital letters are used to indicate objects
1775 * G = glock, I = Inode, R = rgrp, H = holder. Glocks are not indented,
1776 * other objects are indented by a single space and follow the glock to
1777 * which they are related. Fields are indicated by lower case letters
1778 * followed by a colon and the field value, except for strings which are in
1779 * [] so that its possible to see if they are composed of spaces for
1780 * example. The field's are n = number (id of the object), f = flags,
1781 * t = type, s = state, r = refcount, e = error, p = pid.
1785 void gfs2_dump_glock(struct seq_file *seq, struct gfs2_glock *gl, bool fsid)
1787 const struct gfs2_glock_operations *glops = gl->gl_ops;
1788 unsigned long long dtime;
1789 const struct gfs2_holder *gh;
1790 char gflags_buf[32];
1791 char fs_id_buf[GFS2_FSNAME_LEN + 3 * sizeof(int) + 2];
1792 struct gfs2_sbd *sdp = gl->gl_name.ln_sbd;
1794 memset(fs_id_buf, 0, sizeof(fs_id_buf));
1795 if (fsid && sdp) /* safety precaution */
1796 sprintf(fs_id_buf, "fsid=%s: ", sdp->sd_fsname);
1797 dtime = jiffies - gl->gl_demote_time;
1798 dtime *= 1000000/HZ; /* demote time in uSec */
1799 if (!test_bit(GLF_DEMOTE, &gl->gl_flags))
1801 gfs2_print_dbg(seq, "%sG: s:%s n:%u/%llx f:%s t:%s d:%s/%llu a:%d "
1802 "v:%d r:%d m:%ld\n", fs_id_buf, state2str(gl->gl_state),
1803 gl->gl_name.ln_type,
1804 (unsigned long long)gl->gl_name.ln_number,
1805 gflags2str(gflags_buf, gl),
1806 state2str(gl->gl_target),
1807 state2str(gl->gl_demote_state), dtime,
1808 atomic_read(&gl->gl_ail_count),
1809 atomic_read(&gl->gl_revokes),
1810 (int)gl->gl_lockref.count, gl->gl_hold_time);
1812 list_for_each_entry(gh, &gl->gl_holders, gh_list)
1813 dump_holder(seq, gh, fs_id_buf);
1815 if (gl->gl_state != LM_ST_UNLOCKED && glops->go_dump)
1816 glops->go_dump(seq, gl, fs_id_buf);
1819 static int gfs2_glstats_seq_show(struct seq_file *seq, void *iter_ptr)
1821 struct gfs2_glock *gl = iter_ptr;
1823 seq_printf(seq, "G: n:%u/%llx rtt:%llu/%llu rttb:%llu/%llu irt:%llu/%llu dcnt: %llu qcnt: %llu\n",
1824 gl->gl_name.ln_type,
1825 (unsigned long long)gl->gl_name.ln_number,
1826 (unsigned long long)gl->gl_stats.stats[GFS2_LKS_SRTT],
1827 (unsigned long long)gl->gl_stats.stats[GFS2_LKS_SRTTVAR],
1828 (unsigned long long)gl->gl_stats.stats[GFS2_LKS_SRTTB],
1829 (unsigned long long)gl->gl_stats.stats[GFS2_LKS_SRTTVARB],
1830 (unsigned long long)gl->gl_stats.stats[GFS2_LKS_SIRT],
1831 (unsigned long long)gl->gl_stats.stats[GFS2_LKS_SIRTVAR],
1832 (unsigned long long)gl->gl_stats.stats[GFS2_LKS_DCOUNT],
1833 (unsigned long long)gl->gl_stats.stats[GFS2_LKS_QCOUNT]);
1837 static const char *gfs2_gltype[] = {
1851 static const char *gfs2_stype[] = {
1852 [GFS2_LKS_SRTT] = "srtt",
1853 [GFS2_LKS_SRTTVAR] = "srttvar",
1854 [GFS2_LKS_SRTTB] = "srttb",
1855 [GFS2_LKS_SRTTVARB] = "srttvarb",
1856 [GFS2_LKS_SIRT] = "sirt",
1857 [GFS2_LKS_SIRTVAR] = "sirtvar",
1858 [GFS2_LKS_DCOUNT] = "dlm",
1859 [GFS2_LKS_QCOUNT] = "queue",
1862 #define GFS2_NR_SBSTATS (ARRAY_SIZE(gfs2_gltype) * ARRAY_SIZE(gfs2_stype))
1864 static int gfs2_sbstats_seq_show(struct seq_file *seq, void *iter_ptr)
1866 struct gfs2_sbd *sdp = seq->private;
1867 loff_t pos = *(loff_t *)iter_ptr;
1868 unsigned index = pos >> 3;
1869 unsigned subindex = pos & 0x07;
1872 if (index == 0 && subindex != 0)
1875 seq_printf(seq, "%-10s %8s:", gfs2_gltype[index],
1876 (index == 0) ? "cpu": gfs2_stype[subindex]);
1878 for_each_possible_cpu(i) {
1879 const struct gfs2_pcpu_lkstats *lkstats = per_cpu_ptr(sdp->sd_lkstats, i);
1882 seq_printf(seq, " %15u", i);
1884 seq_printf(seq, " %15llu", (unsigned long long)lkstats->
1885 lkstats[index - 1].stats[subindex]);
1887 seq_putc(seq, '\n');
1891 int __init gfs2_glock_init(void)
1895 ret = rhashtable_init(&gl_hash_table, &ht_parms);
1899 glock_workqueue = alloc_workqueue("glock_workqueue", WQ_MEM_RECLAIM |
1900 WQ_HIGHPRI | WQ_FREEZABLE, 0);
1901 if (!glock_workqueue) {
1902 rhashtable_destroy(&gl_hash_table);
1905 gfs2_delete_workqueue = alloc_workqueue("delete_workqueue",
1906 WQ_MEM_RECLAIM | WQ_FREEZABLE,
1908 if (!gfs2_delete_workqueue) {
1909 destroy_workqueue(glock_workqueue);
1910 rhashtable_destroy(&gl_hash_table);
1914 ret = register_shrinker(&glock_shrinker);
1916 destroy_workqueue(gfs2_delete_workqueue);
1917 destroy_workqueue(glock_workqueue);
1918 rhashtable_destroy(&gl_hash_table);
1922 for (i = 0; i < GLOCK_WAIT_TABLE_SIZE; i++)
1923 init_waitqueue_head(glock_wait_table + i);
1928 void gfs2_glock_exit(void)
1930 unregister_shrinker(&glock_shrinker);
1931 rhashtable_destroy(&gl_hash_table);
1932 destroy_workqueue(glock_workqueue);
1933 destroy_workqueue(gfs2_delete_workqueue);
1936 static void gfs2_glock_iter_next(struct gfs2_glock_iter *gi, loff_t n)
1938 struct gfs2_glock *gl = gi->gl;
1943 if (!lockref_put_not_zero(&gl->gl_lockref))
1944 gfs2_glock_queue_put(gl);
1947 gl = rhashtable_walk_next(&gi->hti);
1948 if (IS_ERR_OR_NULL(gl)) {
1949 if (gl == ERR_PTR(-EAGAIN)) {
1956 if (gl->gl_name.ln_sbd != gi->sdp)
1959 if (!lockref_get_not_dead(&gl->gl_lockref))
1963 if (__lockref_is_dead(&gl->gl_lockref))
1971 static void *gfs2_glock_seq_start(struct seq_file *seq, loff_t *pos)
1974 struct gfs2_glock_iter *gi = seq->private;
1978 * We can either stay where we are, skip to the next hash table
1979 * entry, or start from the beginning.
1981 if (*pos < gi->last_pos) {
1982 rhashtable_walk_exit(&gi->hti);
1983 rhashtable_walk_enter(&gl_hash_table, &gi->hti);
1986 n = *pos - gi->last_pos;
1989 rhashtable_walk_start(&gi->hti);
1991 gfs2_glock_iter_next(gi, n);
1992 gi->last_pos = *pos;
1996 static void *gfs2_glock_seq_next(struct seq_file *seq, void *iter_ptr,
1999 struct gfs2_glock_iter *gi = seq->private;
2002 gi->last_pos = *pos;
2003 gfs2_glock_iter_next(gi, 1);
2007 static void gfs2_glock_seq_stop(struct seq_file *seq, void *iter_ptr)
2010 struct gfs2_glock_iter *gi = seq->private;
2012 rhashtable_walk_stop(&gi->hti);
2015 static int gfs2_glock_seq_show(struct seq_file *seq, void *iter_ptr)
2017 dump_glock(seq, iter_ptr, false);
2021 static void *gfs2_sbstats_seq_start(struct seq_file *seq, loff_t *pos)
2024 if (*pos >= GFS2_NR_SBSTATS)
2029 static void *gfs2_sbstats_seq_next(struct seq_file *seq, void *iter_ptr,
2033 if (*pos >= GFS2_NR_SBSTATS)
2038 static void gfs2_sbstats_seq_stop(struct seq_file *seq, void *iter_ptr)
2043 static const struct seq_operations gfs2_glock_seq_ops = {
2044 .start = gfs2_glock_seq_start,
2045 .next = gfs2_glock_seq_next,
2046 .stop = gfs2_glock_seq_stop,
2047 .show = gfs2_glock_seq_show,
2050 static const struct seq_operations gfs2_glstats_seq_ops = {
2051 .start = gfs2_glock_seq_start,
2052 .next = gfs2_glock_seq_next,
2053 .stop = gfs2_glock_seq_stop,
2054 .show = gfs2_glstats_seq_show,
2057 static const struct seq_operations gfs2_sbstats_seq_ops = {
2058 .start = gfs2_sbstats_seq_start,
2059 .next = gfs2_sbstats_seq_next,
2060 .stop = gfs2_sbstats_seq_stop,
2061 .show = gfs2_sbstats_seq_show,
2064 #define GFS2_SEQ_GOODSIZE min(PAGE_SIZE << PAGE_ALLOC_COSTLY_ORDER, 65536UL)
2066 static int __gfs2_glocks_open(struct inode *inode, struct file *file,
2067 const struct seq_operations *ops)
2069 int ret = seq_open_private(file, ops, sizeof(struct gfs2_glock_iter));
2071 struct seq_file *seq = file->private_data;
2072 struct gfs2_glock_iter *gi = seq->private;
2074 gi->sdp = inode->i_private;
2075 seq->buf = kmalloc(GFS2_SEQ_GOODSIZE, GFP_KERNEL | __GFP_NOWARN);
2077 seq->size = GFS2_SEQ_GOODSIZE;
2079 * Initially, we are "before" the first hash table entry; the
2080 * first call to rhashtable_walk_next gets us the first entry.
2084 rhashtable_walk_enter(&gl_hash_table, &gi->hti);
2089 static int gfs2_glocks_open(struct inode *inode, struct file *file)
2091 return __gfs2_glocks_open(inode, file, &gfs2_glock_seq_ops);
2094 static int gfs2_glocks_release(struct inode *inode, struct file *file)
2096 struct seq_file *seq = file->private_data;
2097 struct gfs2_glock_iter *gi = seq->private;
2100 gfs2_glock_put(gi->gl);
2101 rhashtable_walk_exit(&gi->hti);
2102 return seq_release_private(inode, file);
2105 static int gfs2_glstats_open(struct inode *inode, struct file *file)
2107 return __gfs2_glocks_open(inode, file, &gfs2_glstats_seq_ops);
2110 static int gfs2_sbstats_open(struct inode *inode, struct file *file)
2112 int ret = seq_open(file, &gfs2_sbstats_seq_ops);
2114 struct seq_file *seq = file->private_data;
2115 seq->private = inode->i_private; /* sdp */
2120 static const struct file_operations gfs2_glocks_fops = {
2121 .owner = THIS_MODULE,
2122 .open = gfs2_glocks_open,
2124 .llseek = seq_lseek,
2125 .release = gfs2_glocks_release,
2128 static const struct file_operations gfs2_glstats_fops = {
2129 .owner = THIS_MODULE,
2130 .open = gfs2_glstats_open,
2132 .llseek = seq_lseek,
2133 .release = gfs2_glocks_release,
2136 static const struct file_operations gfs2_sbstats_fops = {
2137 .owner = THIS_MODULE,
2138 .open = gfs2_sbstats_open,
2140 .llseek = seq_lseek,
2141 .release = seq_release,
2144 void gfs2_create_debugfs_file(struct gfs2_sbd *sdp)
2146 sdp->debugfs_dir = debugfs_create_dir(sdp->sd_table_name, gfs2_root);
2148 debugfs_create_file("glocks", S_IFREG | S_IRUGO, sdp->debugfs_dir, sdp,
2151 debugfs_create_file("glstats", S_IFREG | S_IRUGO, sdp->debugfs_dir, sdp,
2152 &gfs2_glstats_fops);
2154 debugfs_create_file("sbstats", S_IFREG | S_IRUGO, sdp->debugfs_dir, sdp,
2155 &gfs2_sbstats_fops);
2158 void gfs2_delete_debugfs_file(struct gfs2_sbd *sdp)
2160 debugfs_remove_recursive(sdp->debugfs_dir);
2161 sdp->debugfs_dir = NULL;
2164 void gfs2_register_debugfs(void)
2166 gfs2_root = debugfs_create_dir("gfs2", NULL);
2169 void gfs2_unregister_debugfs(void)
2171 debugfs_remove(gfs2_root);