2 * Copyright (C) Sistina Software, Inc. 1997-2003 All rights reserved.
3 * Copyright (C) 2004-2008 Red Hat, Inc. All rights reserved.
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.
10 #include <linux/sched.h>
11 #include <linux/slab.h>
12 #include <linux/spinlock.h>
13 #include <linux/completion.h>
14 #include <linux/buffer_head.h>
15 #include <linux/delay.h>
16 #include <linux/sort.h>
17 #include <linux/jhash.h>
18 #include <linux/kallsyms.h>
19 #include <linux/gfs2_ondisk.h>
20 #include <linux/list.h>
21 #include <linux/lm_interface.h>
22 #include <linux/wait.h>
23 #include <linux/module.h>
24 #include <linux/rwsem.h>
25 #include <asm/uaccess.h>
26 #include <linux/seq_file.h>
27 #include <linux/debugfs.h>
28 #include <linux/kthread.h>
29 #include <linux/freezer.h>
30 #include <linux/workqueue.h>
31 #include <linux/jiffies.h>
44 struct gfs2_gl_hash_bucket {
45 struct hlist_head hb_list;
49 int hash; /* hash bucket index */
50 struct gfs2_sbd *sdp; /* incore superblock */
51 struct gfs2_glock *gl; /* current glock struct */
52 struct seq_file *seq; /* sequence file for debugfs */
53 char string[512]; /* scratch space */
56 typedef void (*glock_examiner) (struct gfs2_glock * gl);
58 static int gfs2_dump_lockstate(struct gfs2_sbd *sdp);
59 static int dump_glock(struct glock_iter *gi, struct gfs2_glock *gl);
60 static void gfs2_glock_xmote_th(struct gfs2_glock *gl, struct gfs2_holder *gh);
61 static void gfs2_glock_drop_th(struct gfs2_glock *gl);
62 static void run_queue(struct gfs2_glock *gl);
64 static DECLARE_RWSEM(gfs2_umount_flush_sem);
65 static struct dentry *gfs2_root;
66 static struct task_struct *scand_process;
67 static unsigned int scand_secs = 5;
68 static struct workqueue_struct *glock_workqueue;
70 #define GFS2_GL_HASH_SHIFT 15
71 #define GFS2_GL_HASH_SIZE (1 << GFS2_GL_HASH_SHIFT)
72 #define GFS2_GL_HASH_MASK (GFS2_GL_HASH_SIZE - 1)
74 static struct gfs2_gl_hash_bucket gl_hash_table[GFS2_GL_HASH_SIZE];
75 static struct dentry *gfs2_root;
78 * Despite what you might think, the numbers below are not arbitrary :-)
79 * They are taken from the ipv4 routing hash code, which is well tested
80 * and thus should be nearly optimal. Later on we might tweek the numbers
81 * but for now this should be fine.
83 * The reason for putting the locks in a separate array from the list heads
84 * is that we can have fewer locks than list heads and save memory. We use
85 * the same hash function for both, but with a different hash mask.
87 #if defined(CONFIG_SMP) || defined(CONFIG_DEBUG_SPINLOCK) || \
88 defined(CONFIG_PROVE_LOCKING)
91 # define GL_HASH_LOCK_SZ 256
94 # define GL_HASH_LOCK_SZ 4096
96 # define GL_HASH_LOCK_SZ 2048
98 # define GL_HASH_LOCK_SZ 1024
100 # define GL_HASH_LOCK_SZ 512
102 # define GL_HASH_LOCK_SZ 256
106 /* We never want more locks than chains */
107 #if GFS2_GL_HASH_SIZE < GL_HASH_LOCK_SZ
108 # undef GL_HASH_LOCK_SZ
109 # define GL_HASH_LOCK_SZ GFS2_GL_HASH_SIZE
112 static rwlock_t gl_hash_locks[GL_HASH_LOCK_SZ];
114 static inline rwlock_t *gl_lock_addr(unsigned int x)
116 return &gl_hash_locks[x & (GL_HASH_LOCK_SZ-1)];
118 #else /* not SMP, so no spinlocks required */
119 static inline rwlock_t *gl_lock_addr(unsigned int x)
126 * relaxed_state_ok - is a requested lock compatible with the current lock mode?
127 * @actual: the current state of the lock
128 * @requested: the lock state that was requested by the caller
129 * @flags: the modifier flags passed in by the caller
131 * Returns: 1 if the locks are compatible, 0 otherwise
134 static inline int relaxed_state_ok(unsigned int actual, unsigned requested,
137 if (actual == requested)
140 if (flags & GL_EXACT)
143 if (actual == LM_ST_EXCLUSIVE && requested == LM_ST_SHARED)
146 if (actual != LM_ST_UNLOCKED && (flags & LM_FLAG_ANY))
153 * gl_hash() - Turn glock number into hash bucket number
154 * @lock: The glock number
156 * Returns: The number of the corresponding hash bucket
159 static unsigned int gl_hash(const struct gfs2_sbd *sdp,
160 const struct lm_lockname *name)
164 h = jhash(&name->ln_number, sizeof(u64), 0);
165 h = jhash(&name->ln_type, sizeof(unsigned int), h);
166 h = jhash(&sdp, sizeof(struct gfs2_sbd *), h);
167 h &= GFS2_GL_HASH_MASK;
173 * glock_free() - Perform a few checks and then release struct gfs2_glock
174 * @gl: The glock to release
176 * Also calls lock module to release its internal structure for this glock.
180 static void glock_free(struct gfs2_glock *gl)
182 struct gfs2_sbd *sdp = gl->gl_sbd;
183 struct inode *aspace = gl->gl_aspace;
185 if (likely(!test_bit(SDF_SHUTDOWN, &sdp->sd_flags)))
186 sdp->sd_lockstruct.ls_ops->lm_put_lock(gl->gl_lock);
189 gfs2_aspace_put(aspace);
191 kmem_cache_free(gfs2_glock_cachep, gl);
195 * gfs2_glock_hold() - increment reference count on glock
196 * @gl: The glock to hold
200 static void gfs2_glock_hold(struct gfs2_glock *gl)
202 atomic_inc(&gl->gl_ref);
206 * gfs2_glock_put() - Decrement reference count on glock
207 * @gl: The glock to put
211 int gfs2_glock_put(struct gfs2_glock *gl)
214 struct gfs2_sbd *sdp = gl->gl_sbd;
216 write_lock(gl_lock_addr(gl->gl_hash));
217 if (atomic_dec_and_test(&gl->gl_ref)) {
218 hlist_del(&gl->gl_list);
219 write_unlock(gl_lock_addr(gl->gl_hash));
220 gfs2_assert(sdp, gl->gl_state == LM_ST_UNLOCKED);
221 gfs2_assert(sdp, list_empty(&gl->gl_reclaim));
222 gfs2_assert(sdp, list_empty(&gl->gl_holders));
223 gfs2_assert(sdp, list_empty(&gl->gl_waiters1));
224 gfs2_assert(sdp, list_empty(&gl->gl_waiters3));
229 write_unlock(gl_lock_addr(gl->gl_hash));
235 * search_bucket() - Find struct gfs2_glock by lock number
236 * @bucket: the bucket to search
237 * @name: The lock name
239 * Returns: NULL, or the struct gfs2_glock with the requested number
242 static struct gfs2_glock *search_bucket(unsigned int hash,
243 const struct gfs2_sbd *sdp,
244 const struct lm_lockname *name)
246 struct gfs2_glock *gl;
247 struct hlist_node *h;
249 hlist_for_each_entry(gl, h, &gl_hash_table[hash].hb_list, gl_list) {
250 if (!lm_name_equal(&gl->gl_name, name))
252 if (gl->gl_sbd != sdp)
255 atomic_inc(&gl->gl_ref);
264 * gfs2_glock_find() - Find glock by lock number
265 * @sdp: The GFS2 superblock
266 * @name: The lock name
268 * Returns: NULL, or the struct gfs2_glock with the requested number
271 static struct gfs2_glock *gfs2_glock_find(const struct gfs2_sbd *sdp,
272 const struct lm_lockname *name)
274 unsigned int hash = gl_hash(sdp, name);
275 struct gfs2_glock *gl;
277 read_lock(gl_lock_addr(hash));
278 gl = search_bucket(hash, sdp, name);
279 read_unlock(gl_lock_addr(hash));
284 static void glock_work_func(struct work_struct *work)
286 struct gfs2_glock *gl = container_of(work, struct gfs2_glock, gl_work.work);
288 spin_lock(&gl->gl_spin);
289 if (test_and_clear_bit(GLF_PENDING_DEMOTE, &gl->gl_flags))
290 set_bit(GLF_DEMOTE, &gl->gl_flags);
292 spin_unlock(&gl->gl_spin);
296 static int gfs2_lm_get_lock(struct gfs2_sbd *sdp, struct lm_lockname *name,
300 if (likely(!test_bit(SDF_SHUTDOWN, &sdp->sd_flags)))
301 error = sdp->sd_lockstruct.ls_ops->lm_get_lock(
302 sdp->sd_lockstruct.ls_lockspace, name, lockp);
307 * gfs2_glock_get() - Get a glock, or create one if one doesn't exist
308 * @sdp: The GFS2 superblock
309 * @number: the lock number
310 * @glops: The glock_operations to use
311 * @create: If 0, don't create the glock if it doesn't exist
312 * @glp: the glock is returned here
314 * This does not lock a glock, just finds/creates structures for one.
319 int gfs2_glock_get(struct gfs2_sbd *sdp, u64 number,
320 const struct gfs2_glock_operations *glops, int create,
321 struct gfs2_glock **glp)
323 struct lm_lockname name = { .ln_number = number, .ln_type = glops->go_type };
324 struct gfs2_glock *gl, *tmp;
325 unsigned int hash = gl_hash(sdp, &name);
328 read_lock(gl_lock_addr(hash));
329 gl = search_bucket(hash, sdp, &name);
330 read_unlock(gl_lock_addr(hash));
337 gl = kmem_cache_alloc(gfs2_glock_cachep, GFP_KERNEL);
343 atomic_set(&gl->gl_ref, 1);
344 gl->gl_state = LM_ST_UNLOCKED;
345 gl->gl_demote_state = LM_ST_EXCLUSIVE;
347 gl->gl_owner_pid = NULL;
350 gl->gl_req_gh = NULL;
351 gl->gl_stamp = jiffies;
352 gl->gl_tchange = jiffies;
353 gl->gl_object = NULL;
355 gl->gl_aspace = NULL;
356 INIT_DELAYED_WORK(&gl->gl_work, glock_work_func);
358 /* If this glock protects actual on-disk data or metadata blocks,
359 create a VFS inode to manage the pages/buffers holding them. */
360 if (glops == &gfs2_inode_glops || glops == &gfs2_rgrp_glops) {
361 gl->gl_aspace = gfs2_aspace_get(sdp);
362 if (!gl->gl_aspace) {
368 error = gfs2_lm_get_lock(sdp, &name, &gl->gl_lock);
372 write_lock(gl_lock_addr(hash));
373 tmp = search_bucket(hash, sdp, &name);
375 write_unlock(gl_lock_addr(hash));
379 hlist_add_head(&gl->gl_list, &gl_hash_table[hash].hb_list);
380 write_unlock(gl_lock_addr(hash));
389 gfs2_aspace_put(gl->gl_aspace);
391 kmem_cache_free(gfs2_glock_cachep, gl);
396 * gfs2_holder_init - initialize a struct gfs2_holder in the default way
398 * @state: the state we're requesting
399 * @flags: the modifier flags
400 * @gh: the holder structure
404 void gfs2_holder_init(struct gfs2_glock *gl, unsigned int state, unsigned flags,
405 struct gfs2_holder *gh)
407 INIT_LIST_HEAD(&gh->gh_list);
409 gh->gh_ip = (unsigned long)__builtin_return_address(0);
410 gh->gh_owner_pid = get_pid(task_pid(current));
411 gh->gh_state = state;
412 gh->gh_flags = flags;
419 * gfs2_holder_reinit - reinitialize a struct gfs2_holder so we can requeue it
420 * @state: the state we're requesting
421 * @flags: the modifier flags
422 * @gh: the holder structure
424 * Don't mess with the glock.
428 void gfs2_holder_reinit(unsigned int state, unsigned flags, struct gfs2_holder *gh)
430 gh->gh_state = state;
431 gh->gh_flags = flags;
433 gh->gh_ip = (unsigned long)__builtin_return_address(0);
437 * gfs2_holder_uninit - uninitialize a holder structure (drop glock reference)
438 * @gh: the holder structure
442 void gfs2_holder_uninit(struct gfs2_holder *gh)
444 put_pid(gh->gh_owner_pid);
445 gfs2_glock_put(gh->gh_gl);
450 static void gfs2_holder_wake(struct gfs2_holder *gh)
452 clear_bit(HIF_WAIT, &gh->gh_iflags);
453 smp_mb__after_clear_bit();
454 wake_up_bit(&gh->gh_iflags, HIF_WAIT);
457 static int just_schedule(void *word)
463 static void wait_on_holder(struct gfs2_holder *gh)
466 wait_on_bit(&gh->gh_iflags, HIF_WAIT, just_schedule, TASK_UNINTERRUPTIBLE);
469 static void gfs2_demote_wake(struct gfs2_glock *gl)
471 gl->gl_demote_state = LM_ST_EXCLUSIVE;
472 clear_bit(GLF_DEMOTE, &gl->gl_flags);
473 smp_mb__after_clear_bit();
474 wake_up_bit(&gl->gl_flags, GLF_DEMOTE);
477 static void wait_on_demote(struct gfs2_glock *gl)
480 wait_on_bit(&gl->gl_flags, GLF_DEMOTE, just_schedule, TASK_UNINTERRUPTIBLE);
484 * rq_mutex - process a mutex request in the queue
485 * @gh: the glock holder
487 * Returns: 1 if the queue is blocked
490 static int rq_mutex(struct gfs2_holder *gh)
492 struct gfs2_glock *gl = gh->gh_gl;
494 list_del_init(&gh->gh_list);
495 /* gh->gh_error never examined. */
496 set_bit(GLF_LOCK, &gl->gl_flags);
497 clear_bit(HIF_WAIT, &gh->gh_iflags);
499 wake_up_bit(&gh->gh_iflags, HIF_WAIT);
505 * rq_promote - process a promote request in the queue
506 * @gh: the glock holder
508 * Acquire a new inter-node lock, or change a lock state to more restrictive.
510 * Returns: 1 if the queue is blocked
513 static int rq_promote(struct gfs2_holder *gh)
515 struct gfs2_glock *gl = gh->gh_gl;
517 if (!relaxed_state_ok(gl->gl_state, gh->gh_state, gh->gh_flags)) {
518 if (list_empty(&gl->gl_holders)) {
520 set_bit(GLF_LOCK, &gl->gl_flags);
521 spin_unlock(&gl->gl_spin);
522 gfs2_glock_xmote_th(gh->gh_gl, gh);
523 spin_lock(&gl->gl_spin);
528 if (list_empty(&gl->gl_holders)) {
529 set_bit(HIF_FIRST, &gh->gh_iflags);
530 set_bit(GLF_LOCK, &gl->gl_flags);
532 struct gfs2_holder *next_gh;
533 if (gh->gh_state == LM_ST_EXCLUSIVE)
535 next_gh = list_entry(gl->gl_holders.next, struct gfs2_holder,
537 if (next_gh->gh_state == LM_ST_EXCLUSIVE)
541 list_move_tail(&gh->gh_list, &gl->gl_holders);
543 set_bit(HIF_HOLDER, &gh->gh_iflags);
545 gfs2_holder_wake(gh);
551 * rq_demote - process a demote request in the queue
552 * @gh: the glock holder
554 * Returns: 1 if the queue is blocked
557 static int rq_demote(struct gfs2_glock *gl)
559 if (!list_empty(&gl->gl_holders))
562 if (gl->gl_state == gl->gl_demote_state ||
563 gl->gl_state == LM_ST_UNLOCKED) {
564 gfs2_demote_wake(gl);
568 set_bit(GLF_LOCK, &gl->gl_flags);
569 set_bit(GLF_DEMOTE_IN_PROGRESS, &gl->gl_flags);
571 if (gl->gl_demote_state == LM_ST_UNLOCKED ||
572 gl->gl_state != LM_ST_EXCLUSIVE) {
573 spin_unlock(&gl->gl_spin);
574 gfs2_glock_drop_th(gl);
576 spin_unlock(&gl->gl_spin);
577 gfs2_glock_xmote_th(gl, NULL);
580 spin_lock(&gl->gl_spin);
581 clear_bit(GLF_DEMOTE_IN_PROGRESS, &gl->gl_flags);
587 * run_queue - process holder structures on a glock
591 static void run_queue(struct gfs2_glock *gl)
593 struct gfs2_holder *gh;
597 if (test_bit(GLF_LOCK, &gl->gl_flags))
600 if (!list_empty(&gl->gl_waiters1)) {
601 gh = list_entry(gl->gl_waiters1.next,
602 struct gfs2_holder, gh_list);
603 blocked = rq_mutex(gh);
604 } else if (test_bit(GLF_DEMOTE, &gl->gl_flags)) {
605 blocked = rq_demote(gl);
606 if (test_bit(GLF_WAITERS2, &gl->gl_flags) &&
608 set_bit(GLF_DEMOTE, &gl->gl_flags);
609 gl->gl_demote_state = LM_ST_UNLOCKED;
611 clear_bit(GLF_WAITERS2, &gl->gl_flags);
612 } else if (!list_empty(&gl->gl_waiters3)) {
613 gh = list_entry(gl->gl_waiters3.next,
614 struct gfs2_holder, gh_list);
615 blocked = rq_promote(gh);
625 * gfs2_glmutex_lock - acquire a local lock on a glock
628 * Gives caller exclusive access to manipulate a glock structure.
631 static void gfs2_glmutex_lock(struct gfs2_glock *gl)
633 spin_lock(&gl->gl_spin);
634 if (test_and_set_bit(GLF_LOCK, &gl->gl_flags)) {
635 struct gfs2_holder gh;
637 gfs2_holder_init(gl, 0, 0, &gh);
638 set_bit(HIF_WAIT, &gh.gh_iflags);
639 list_add_tail(&gh.gh_list, &gl->gl_waiters1);
640 spin_unlock(&gl->gl_spin);
642 gfs2_holder_uninit(&gh);
644 gl->gl_owner_pid = get_pid(task_pid(current));
645 gl->gl_ip = (unsigned long)__builtin_return_address(0);
646 spin_unlock(&gl->gl_spin);
651 * gfs2_glmutex_trylock - try to acquire a local lock on a glock
654 * Returns: 1 if the glock is acquired
657 static int gfs2_glmutex_trylock(struct gfs2_glock *gl)
661 spin_lock(&gl->gl_spin);
662 if (test_and_set_bit(GLF_LOCK, &gl->gl_flags)) {
665 gl->gl_owner_pid = get_pid(task_pid(current));
666 gl->gl_ip = (unsigned long)__builtin_return_address(0);
668 spin_unlock(&gl->gl_spin);
674 * gfs2_glmutex_unlock - release a local lock on a glock
679 static void gfs2_glmutex_unlock(struct gfs2_glock *gl)
683 spin_lock(&gl->gl_spin);
684 clear_bit(GLF_LOCK, &gl->gl_flags);
685 pid = gl->gl_owner_pid;
686 gl->gl_owner_pid = NULL;
689 spin_unlock(&gl->gl_spin);
695 * handle_callback - process a demote request
697 * @state: the state the caller wants us to change to
699 * There are only two requests that we are going to see in actual
700 * practise: LM_ST_SHARED and LM_ST_UNLOCKED
703 static void handle_callback(struct gfs2_glock *gl, unsigned int state,
704 int remote, unsigned long delay)
706 int bit = delay ? GLF_PENDING_DEMOTE : GLF_DEMOTE;
708 spin_lock(&gl->gl_spin);
709 set_bit(bit, &gl->gl_flags);
710 if (gl->gl_demote_state == LM_ST_EXCLUSIVE) {
711 gl->gl_demote_state = state;
712 gl->gl_demote_time = jiffies;
713 if (remote && gl->gl_ops->go_type == LM_TYPE_IOPEN &&
715 gfs2_glock_schedule_for_reclaim(gl);
716 spin_unlock(&gl->gl_spin);
719 } else if (gl->gl_demote_state != LM_ST_UNLOCKED &&
720 gl->gl_demote_state != state) {
721 if (test_bit(GLF_DEMOTE_IN_PROGRESS, &gl->gl_flags))
722 set_bit(GLF_WAITERS2, &gl->gl_flags);
724 gl->gl_demote_state = LM_ST_UNLOCKED;
726 spin_unlock(&gl->gl_spin);
730 * state_change - record that the glock is now in a different state
732 * @new_state the new state
736 static void state_change(struct gfs2_glock *gl, unsigned int new_state)
740 held1 = (gl->gl_state != LM_ST_UNLOCKED);
741 held2 = (new_state != LM_ST_UNLOCKED);
743 if (held1 != held2) {
750 gl->gl_state = new_state;
751 gl->gl_tchange = jiffies;
755 * drop_bh - Called after a lock module unlock completes
757 * @ret: the return status
759 * Doesn't wake up the process waiting on the struct gfs2_holder (if any)
760 * Doesn't drop the reference on the glock the top half took out
764 static void drop_bh(struct gfs2_glock *gl, unsigned int ret)
766 struct gfs2_sbd *sdp = gl->gl_sbd;
767 const struct gfs2_glock_operations *glops = gl->gl_ops;
769 gfs2_assert_warn(sdp, test_bit(GLF_LOCK, &gl->gl_flags));
770 gfs2_assert_warn(sdp, list_empty(&gl->gl_holders));
771 gfs2_assert_warn(sdp, !ret);
773 state_change(gl, LM_ST_UNLOCKED);
776 glops->go_inval(gl, DIO_METADATA);
778 spin_lock(&gl->gl_spin);
779 gfs2_demote_wake(gl);
780 clear_bit(GLF_LOCK, &gl->gl_flags);
781 spin_unlock(&gl->gl_spin);
786 * xmote_bh - Called after the lock module is done acquiring a lock
787 * @gl: The glock in question
788 * @ret: the int returned from the lock module
792 static void xmote_bh(struct gfs2_glock *gl, unsigned int ret)
794 struct gfs2_sbd *sdp = gl->gl_sbd;
795 const struct gfs2_glock_operations *glops = gl->gl_ops;
796 struct gfs2_holder *gh = gl->gl_req_gh;
797 int prev_state = gl->gl_state;
800 if (!gh && (ret & LM_OUT_ST_MASK) == LM_ST_UNLOCKED) {
805 gfs2_assert_warn(sdp, test_bit(GLF_LOCK, &gl->gl_flags));
806 gfs2_assert_warn(sdp, list_empty(&gl->gl_holders));
807 gfs2_assert_warn(sdp, !(ret & LM_OUT_ASYNC));
809 state_change(gl, ret & LM_OUT_ST_MASK);
811 if (prev_state != LM_ST_UNLOCKED && !(ret & LM_OUT_CACHEABLE)) {
813 glops->go_inval(gl, DIO_METADATA);
814 } else if (gl->gl_state == LM_ST_DEFERRED) {
815 /* We might not want to do this here.
816 Look at moving to the inode glops. */
818 glops->go_inval(gl, 0);
821 /* Deal with each possible exit condition */
824 gl->gl_stamp = jiffies;
825 if (ret & LM_OUT_CANCELED) {
828 spin_lock(&gl->gl_spin);
829 if (gl->gl_state != gl->gl_demote_state) {
830 spin_unlock(&gl->gl_spin);
831 gfs2_glock_drop_th(gl);
835 gfs2_demote_wake(gl);
836 spin_unlock(&gl->gl_spin);
839 spin_lock(&gl->gl_spin);
840 list_del_init(&gh->gh_list);
842 if (unlikely(test_bit(SDF_SHUTDOWN, &sdp->sd_flags)))
844 gh->gh_error = GLR_CANCELED;
845 if (ret & LM_OUT_CANCELED)
847 if (relaxed_state_ok(gl->gl_state, gh->gh_state, gh->gh_flags)) {
848 list_add_tail(&gh->gh_list, &gl->gl_holders);
850 set_bit(HIF_HOLDER, &gh->gh_iflags);
851 set_bit(HIF_FIRST, &gh->gh_iflags);
855 gh->gh_error = GLR_TRYFAILED;
856 if (gh->gh_flags & (LM_FLAG_TRY | LM_FLAG_TRY_1CB))
858 gh->gh_error = -EINVAL;
859 if (gfs2_assert_withdraw(sdp, 0) == -1)
860 fs_err(sdp, "ret = 0x%.8X\n", ret);
862 spin_unlock(&gl->gl_spin);
865 if (glops->go_xmote_bh)
866 glops->go_xmote_bh(gl);
869 spin_lock(&gl->gl_spin);
870 gl->gl_req_gh = NULL;
871 clear_bit(GLF_LOCK, &gl->gl_flags);
872 spin_unlock(&gl->gl_spin);
878 gfs2_holder_wake(gh);
881 static unsigned int gfs2_lm_lock(struct gfs2_sbd *sdp, void *lock,
882 unsigned int cur_state, unsigned int req_state,
886 if (likely(!test_bit(SDF_SHUTDOWN, &sdp->sd_flags)))
887 ret = sdp->sd_lockstruct.ls_ops->lm_lock(lock, cur_state,
893 * gfs2_glock_xmote_th - Call into the lock module to acquire or change a glock
894 * @gl: The glock in question
895 * @state: the requested state
896 * @flags: modifier flags to the lock call
900 static void gfs2_glock_xmote_th(struct gfs2_glock *gl, struct gfs2_holder *gh)
902 struct gfs2_sbd *sdp = gl->gl_sbd;
903 int flags = gh ? gh->gh_flags : 0;
904 unsigned state = gh ? gh->gh_state : gl->gl_demote_state;
905 const struct gfs2_glock_operations *glops = gl->gl_ops;
906 int lck_flags = flags & (LM_FLAG_TRY | LM_FLAG_TRY_1CB |
907 LM_FLAG_NOEXP | LM_FLAG_ANY |
909 unsigned int lck_ret;
911 if (glops->go_xmote_th)
912 glops->go_xmote_th(gl);
914 gfs2_assert_warn(sdp, test_bit(GLF_LOCK, &gl->gl_flags));
915 gfs2_assert_warn(sdp, list_empty(&gl->gl_holders));
916 gfs2_assert_warn(sdp, state != LM_ST_UNLOCKED);
917 gfs2_assert_warn(sdp, state != gl->gl_state);
921 lck_ret = gfs2_lm_lock(sdp, gl->gl_lock, gl->gl_state, state, lck_flags);
923 if (gfs2_assert_withdraw(sdp, !(lck_ret & LM_OUT_ERROR)))
926 if (lck_ret & LM_OUT_ASYNC)
927 gfs2_assert_warn(sdp, lck_ret == LM_OUT_ASYNC);
929 xmote_bh(gl, lck_ret);
932 static unsigned int gfs2_lm_unlock(struct gfs2_sbd *sdp, void *lock,
933 unsigned int cur_state)
936 if (likely(!test_bit(SDF_SHUTDOWN, &sdp->sd_flags)))
937 ret = sdp->sd_lockstruct.ls_ops->lm_unlock(lock, cur_state);
942 * gfs2_glock_drop_th - call into the lock module to unlock a lock
947 static void gfs2_glock_drop_th(struct gfs2_glock *gl)
949 struct gfs2_sbd *sdp = gl->gl_sbd;
950 const struct gfs2_glock_operations *glops = gl->gl_ops;
953 if (glops->go_xmote_th)
954 glops->go_xmote_th(gl);
956 gfs2_assert_warn(sdp, test_bit(GLF_LOCK, &gl->gl_flags));
957 gfs2_assert_warn(sdp, list_empty(&gl->gl_holders));
958 gfs2_assert_warn(sdp, gl->gl_state != LM_ST_UNLOCKED);
962 ret = gfs2_lm_unlock(sdp, gl->gl_lock, gl->gl_state);
964 if (gfs2_assert_withdraw(sdp, !(ret & LM_OUT_ERROR)))
970 gfs2_assert_warn(sdp, ret == LM_OUT_ASYNC);
974 * do_cancels - cancel requests for locks stuck waiting on an expire flag
975 * @gh: the LM_FLAG_PRIORITY holder waiting to acquire the lock
977 * Don't cancel GL_NOCANCEL requests.
980 static void do_cancels(struct gfs2_holder *gh)
982 struct gfs2_glock *gl = gh->gh_gl;
983 struct gfs2_sbd *sdp = gl->gl_sbd;
985 spin_lock(&gl->gl_spin);
987 while (gl->gl_req_gh != gh &&
988 !test_bit(HIF_HOLDER, &gh->gh_iflags) &&
989 !list_empty(&gh->gh_list)) {
990 if (!(gl->gl_req_gh && (gl->gl_req_gh->gh_flags & GL_NOCANCEL))) {
991 spin_unlock(&gl->gl_spin);
992 if (likely(!test_bit(SDF_SHUTDOWN, &sdp->sd_flags)))
993 sdp->sd_lockstruct.ls_ops->lm_cancel(gl->gl_lock);
995 spin_lock(&gl->gl_spin);
997 spin_unlock(&gl->gl_spin);
999 spin_lock(&gl->gl_spin);
1003 spin_unlock(&gl->gl_spin);
1007 * glock_wait_internal - wait on a glock acquisition
1008 * @gh: the glock holder
1010 * Returns: 0 on success
1013 static int glock_wait_internal(struct gfs2_holder *gh)
1015 struct gfs2_glock *gl = gh->gh_gl;
1016 struct gfs2_sbd *sdp = gl->gl_sbd;
1017 const struct gfs2_glock_operations *glops = gl->gl_ops;
1019 if (test_bit(HIF_ABORTED, &gh->gh_iflags))
1022 if (gh->gh_flags & (LM_FLAG_TRY | LM_FLAG_TRY_1CB)) {
1023 spin_lock(&gl->gl_spin);
1024 if (gl->gl_req_gh != gh &&
1025 !test_bit(HIF_HOLDER, &gh->gh_iflags) &&
1026 !list_empty(&gh->gh_list)) {
1027 list_del_init(&gh->gh_list);
1028 gh->gh_error = GLR_TRYFAILED;
1030 spin_unlock(&gl->gl_spin);
1031 return gh->gh_error;
1033 spin_unlock(&gl->gl_spin);
1036 if (gh->gh_flags & LM_FLAG_PRIORITY)
1041 return gh->gh_error;
1043 gfs2_assert_withdraw(sdp, test_bit(HIF_HOLDER, &gh->gh_iflags));
1044 gfs2_assert_withdraw(sdp, relaxed_state_ok(gl->gl_state, gh->gh_state,
1047 if (test_bit(HIF_FIRST, &gh->gh_iflags)) {
1048 gfs2_assert_warn(sdp, test_bit(GLF_LOCK, &gl->gl_flags));
1050 if (glops->go_lock) {
1051 gh->gh_error = glops->go_lock(gh);
1053 spin_lock(&gl->gl_spin);
1054 list_del_init(&gh->gh_list);
1055 spin_unlock(&gl->gl_spin);
1059 spin_lock(&gl->gl_spin);
1060 gl->gl_req_gh = NULL;
1061 clear_bit(GLF_LOCK, &gl->gl_flags);
1063 spin_unlock(&gl->gl_spin);
1066 return gh->gh_error;
1069 static inline struct gfs2_holder *
1070 find_holder_by_owner(struct list_head *head, struct pid *pid)
1072 struct gfs2_holder *gh;
1074 list_for_each_entry(gh, head, gh_list) {
1075 if (gh->gh_owner_pid == pid)
1082 static void print_dbg(struct glock_iter *gi, const char *fmt, ...)
1086 va_start(args, fmt);
1088 vsprintf(gi->string, fmt, args);
1089 seq_printf(gi->seq, gi->string);
1097 * add_to_queue - Add a holder to the wait queue (but look for recursion)
1098 * @gh: the holder structure to add
1102 static void add_to_queue(struct gfs2_holder *gh)
1104 struct gfs2_glock *gl = gh->gh_gl;
1105 struct gfs2_holder *existing;
1107 BUG_ON(gh->gh_owner_pid == NULL);
1108 if (test_and_set_bit(HIF_WAIT, &gh->gh_iflags))
1111 if (!(gh->gh_flags & GL_FLOCK)) {
1112 existing = find_holder_by_owner(&gl->gl_holders,
1115 print_symbol(KERN_WARNING "original: %s\n",
1117 printk(KERN_INFO "pid : %d\n",
1118 pid_nr(existing->gh_owner_pid));
1119 printk(KERN_INFO "lock type : %d lock state : %d\n",
1120 existing->gh_gl->gl_name.ln_type,
1121 existing->gh_gl->gl_state);
1122 print_symbol(KERN_WARNING "new: %s\n", gh->gh_ip);
1123 printk(KERN_INFO "pid : %d\n",
1124 pid_nr(gh->gh_owner_pid));
1125 printk(KERN_INFO "lock type : %d lock state : %d\n",
1126 gl->gl_name.ln_type, gl->gl_state);
1130 existing = find_holder_by_owner(&gl->gl_waiters3,
1133 print_symbol(KERN_WARNING "original: %s\n",
1135 print_symbol(KERN_WARNING "new: %s\n", gh->gh_ip);
1140 if (gh->gh_flags & LM_FLAG_PRIORITY)
1141 list_add(&gh->gh_list, &gl->gl_waiters3);
1143 list_add_tail(&gh->gh_list, &gl->gl_waiters3);
1147 * gfs2_glock_nq - enqueue a struct gfs2_holder onto a glock (acquire a glock)
1148 * @gh: the holder structure
1150 * if (gh->gh_flags & GL_ASYNC), this never returns an error
1152 * Returns: 0, GLR_TRYFAILED, or errno on failure
1155 int gfs2_glock_nq(struct gfs2_holder *gh)
1157 struct gfs2_glock *gl = gh->gh_gl;
1158 struct gfs2_sbd *sdp = gl->gl_sbd;
1162 if (unlikely(test_bit(SDF_SHUTDOWN, &sdp->sd_flags))) {
1163 set_bit(HIF_ABORTED, &gh->gh_iflags);
1167 spin_lock(&gl->gl_spin);
1170 spin_unlock(&gl->gl_spin);
1172 if (!(gh->gh_flags & GL_ASYNC)) {
1173 error = glock_wait_internal(gh);
1174 if (error == GLR_CANCELED) {
1184 * gfs2_glock_poll - poll to see if an async request has been completed
1187 * Returns: 1 if the request is ready to be gfs2_glock_wait()ed on
1190 int gfs2_glock_poll(struct gfs2_holder *gh)
1192 struct gfs2_glock *gl = gh->gh_gl;
1195 spin_lock(&gl->gl_spin);
1197 if (test_bit(HIF_HOLDER, &gh->gh_iflags))
1199 else if (list_empty(&gh->gh_list)) {
1200 if (gh->gh_error == GLR_CANCELED) {
1201 spin_unlock(&gl->gl_spin);
1203 if (gfs2_glock_nq(gh))
1210 spin_unlock(&gl->gl_spin);
1216 * gfs2_glock_wait - wait for a lock acquisition that ended in a GLR_ASYNC
1217 * @gh: the holder structure
1219 * Returns: 0, GLR_TRYFAILED, or errno on failure
1222 int gfs2_glock_wait(struct gfs2_holder *gh)
1226 error = glock_wait_internal(gh);
1227 if (error == GLR_CANCELED) {
1229 gh->gh_flags &= ~GL_ASYNC;
1230 error = gfs2_glock_nq(gh);
1237 * gfs2_glock_dq - dequeue a struct gfs2_holder from a glock (release a glock)
1238 * @gh: the glock holder
1242 void gfs2_glock_dq(struct gfs2_holder *gh)
1244 struct gfs2_glock *gl = gh->gh_gl;
1245 const struct gfs2_glock_operations *glops = gl->gl_ops;
1248 if (gh->gh_flags & GL_NOCACHE)
1249 handle_callback(gl, LM_ST_UNLOCKED, 0, 0);
1251 gfs2_glmutex_lock(gl);
1253 spin_lock(&gl->gl_spin);
1254 list_del_init(&gh->gh_list);
1256 if (list_empty(&gl->gl_holders)) {
1257 if (glops->go_unlock) {
1258 spin_unlock(&gl->gl_spin);
1259 glops->go_unlock(gh);
1260 spin_lock(&gl->gl_spin);
1262 gl->gl_stamp = jiffies;
1265 clear_bit(GLF_LOCK, &gl->gl_flags);
1266 spin_unlock(&gl->gl_spin);
1268 gfs2_glock_hold(gl);
1269 if (test_bit(GLF_PENDING_DEMOTE, &gl->gl_flags) &&
1270 !test_bit(GLF_DEMOTE, &gl->gl_flags))
1271 delay = gl->gl_ops->go_min_hold_time;
1272 if (queue_delayed_work(glock_workqueue, &gl->gl_work, delay) == 0)
1276 void gfs2_glock_dq_wait(struct gfs2_holder *gh)
1278 struct gfs2_glock *gl = gh->gh_gl;
1284 * gfs2_glock_dq_uninit - dequeue a holder from a glock and initialize it
1285 * @gh: the holder structure
1289 void gfs2_glock_dq_uninit(struct gfs2_holder *gh)
1292 gfs2_holder_uninit(gh);
1296 * gfs2_glock_nq_num - acquire a glock based on lock number
1297 * @sdp: the filesystem
1298 * @number: the lock number
1299 * @glops: the glock operations for the type of glock
1300 * @state: the state to acquire the glock in
1301 * @flags: modifier flags for the aquisition
1302 * @gh: the struct gfs2_holder
1307 int gfs2_glock_nq_num(struct gfs2_sbd *sdp, u64 number,
1308 const struct gfs2_glock_operations *glops,
1309 unsigned int state, int flags, struct gfs2_holder *gh)
1311 struct gfs2_glock *gl;
1314 error = gfs2_glock_get(sdp, number, glops, CREATE, &gl);
1316 error = gfs2_glock_nq_init(gl, state, flags, gh);
1324 * glock_compare - Compare two struct gfs2_glock structures for sorting
1325 * @arg_a: the first structure
1326 * @arg_b: the second structure
1330 static int glock_compare(const void *arg_a, const void *arg_b)
1332 const struct gfs2_holder *gh_a = *(const struct gfs2_holder **)arg_a;
1333 const struct gfs2_holder *gh_b = *(const struct gfs2_holder **)arg_b;
1334 const struct lm_lockname *a = &gh_a->gh_gl->gl_name;
1335 const struct lm_lockname *b = &gh_b->gh_gl->gl_name;
1337 if (a->ln_number > b->ln_number)
1339 if (a->ln_number < b->ln_number)
1341 BUG_ON(gh_a->gh_gl->gl_ops->go_type == gh_b->gh_gl->gl_ops->go_type);
1346 * nq_m_sync - synchonously acquire more than one glock in deadlock free order
1347 * @num_gh: the number of structures
1348 * @ghs: an array of struct gfs2_holder structures
1350 * Returns: 0 on success (all glocks acquired),
1351 * errno on failure (no glocks acquired)
1354 static int nq_m_sync(unsigned int num_gh, struct gfs2_holder *ghs,
1355 struct gfs2_holder **p)
1360 for (x = 0; x < num_gh; x++)
1363 sort(p, num_gh, sizeof(struct gfs2_holder *), glock_compare, NULL);
1365 for (x = 0; x < num_gh; x++) {
1366 p[x]->gh_flags &= ~(LM_FLAG_TRY | GL_ASYNC);
1368 error = gfs2_glock_nq(p[x]);
1371 gfs2_glock_dq(p[x]);
1380 * gfs2_glock_nq_m - acquire multiple glocks
1381 * @num_gh: the number of structures
1382 * @ghs: an array of struct gfs2_holder structures
1385 * Returns: 0 on success (all glocks acquired),
1386 * errno on failure (no glocks acquired)
1389 int gfs2_glock_nq_m(unsigned int num_gh, struct gfs2_holder *ghs)
1391 struct gfs2_holder *tmp[4];
1392 struct gfs2_holder **pph = tmp;
1399 ghs->gh_flags &= ~(LM_FLAG_TRY | GL_ASYNC);
1400 return gfs2_glock_nq(ghs);
1404 pph = kmalloc(num_gh * sizeof(struct gfs2_holder *), GFP_NOFS);
1409 error = nq_m_sync(num_gh, ghs, pph);
1418 * gfs2_glock_dq_m - release multiple glocks
1419 * @num_gh: the number of structures
1420 * @ghs: an array of struct gfs2_holder structures
1424 void gfs2_glock_dq_m(unsigned int num_gh, struct gfs2_holder *ghs)
1428 for (x = 0; x < num_gh; x++)
1429 gfs2_glock_dq(&ghs[x]);
1433 * gfs2_glock_dq_uninit_m - release multiple glocks
1434 * @num_gh: the number of structures
1435 * @ghs: an array of struct gfs2_holder structures
1439 void gfs2_glock_dq_uninit_m(unsigned int num_gh, struct gfs2_holder *ghs)
1443 for (x = 0; x < num_gh; x++)
1444 gfs2_glock_dq_uninit(&ghs[x]);
1447 static int gfs2_lm_hold_lvb(struct gfs2_sbd *sdp, void *lock, char **lvbp)
1450 if (likely(!test_bit(SDF_SHUTDOWN, &sdp->sd_flags)))
1451 error = sdp->sd_lockstruct.ls_ops->lm_hold_lvb(lock, lvbp);
1456 * gfs2_lvb_hold - attach a LVB from a glock
1457 * @gl: The glock in question
1461 int gfs2_lvb_hold(struct gfs2_glock *gl)
1465 gfs2_glmutex_lock(gl);
1467 if (!atomic_read(&gl->gl_lvb_count)) {
1468 error = gfs2_lm_hold_lvb(gl->gl_sbd, gl->gl_lock, &gl->gl_lvb);
1470 gfs2_glmutex_unlock(gl);
1473 gfs2_glock_hold(gl);
1475 atomic_inc(&gl->gl_lvb_count);
1477 gfs2_glmutex_unlock(gl);
1483 * gfs2_lvb_unhold - detach a LVB from a glock
1484 * @gl: The glock in question
1488 void gfs2_lvb_unhold(struct gfs2_glock *gl)
1490 struct gfs2_sbd *sdp = gl->gl_sbd;
1492 gfs2_glock_hold(gl);
1493 gfs2_glmutex_lock(gl);
1495 gfs2_assert(gl->gl_sbd, atomic_read(&gl->gl_lvb_count) > 0);
1496 if (atomic_dec_and_test(&gl->gl_lvb_count)) {
1497 if (likely(!test_bit(SDF_SHUTDOWN, &sdp->sd_flags)))
1498 sdp->sd_lockstruct.ls_ops->lm_unhold_lvb(gl->gl_lock, gl->gl_lvb);
1503 gfs2_glmutex_unlock(gl);
1507 static void blocking_cb(struct gfs2_sbd *sdp, struct lm_lockname *name,
1510 struct gfs2_glock *gl;
1511 unsigned long delay = 0;
1512 unsigned long holdtime;
1513 unsigned long now = jiffies;
1515 gl = gfs2_glock_find(sdp, name);
1519 holdtime = gl->gl_tchange + gl->gl_ops->go_min_hold_time;
1520 if (time_before(now, holdtime))
1521 delay = holdtime - now;
1523 handle_callback(gl, state, 1, delay);
1524 if (queue_delayed_work(glock_workqueue, &gl->gl_work, delay) == 0)
1529 * gfs2_glock_cb - Callback used by locking module
1530 * @sdp: Pointer to the superblock
1531 * @type: Type of callback
1532 * @data: Type dependent data pointer
1534 * Called by the locking module when it wants to tell us something.
1535 * Either we need to drop a lock, one of our ASYNC requests completed, or
1536 * a journal from another client needs to be recovered.
1539 void gfs2_glock_cb(void *cb_data, unsigned int type, void *data)
1541 struct gfs2_sbd *sdp = cb_data;
1545 blocking_cb(sdp, data, LM_ST_UNLOCKED);
1549 blocking_cb(sdp, data, LM_ST_DEFERRED);
1553 blocking_cb(sdp, data, LM_ST_SHARED);
1557 struct lm_async_cb *async = data;
1558 struct gfs2_glock *gl;
1560 down_read(&gfs2_umount_flush_sem);
1561 gl = gfs2_glock_find(sdp, &async->lc_name);
1562 if (gfs2_assert_warn(sdp, gl))
1564 xmote_bh(gl, async->lc_ret);
1565 if (queue_delayed_work(glock_workqueue, &gl->gl_work, 0) == 0)
1567 up_read(&gfs2_umount_flush_sem);
1571 case LM_CB_NEED_RECOVERY:
1572 gfs2_jdesc_make_dirty(sdp, *(unsigned int *)data);
1573 if (sdp->sd_recoverd_process)
1574 wake_up_process(sdp->sd_recoverd_process);
1577 case LM_CB_DROPLOCKS:
1578 gfs2_gl_hash_clear(sdp, NO_WAIT);
1579 gfs2_quota_scan(sdp);
1583 gfs2_assert_warn(sdp, 0);
1589 * demote_ok - Check to see if it's ok to unlock a glock
1592 * Returns: 1 if it's ok
1595 static int demote_ok(struct gfs2_glock *gl)
1597 const struct gfs2_glock_operations *glops = gl->gl_ops;
1600 if (test_bit(GLF_STICKY, &gl->gl_flags))
1602 else if (glops->go_demote_ok)
1603 demote = glops->go_demote_ok(gl);
1609 * gfs2_glock_schedule_for_reclaim - Add a glock to the reclaim list
1614 void gfs2_glock_schedule_for_reclaim(struct gfs2_glock *gl)
1616 struct gfs2_sbd *sdp = gl->gl_sbd;
1618 spin_lock(&sdp->sd_reclaim_lock);
1619 if (list_empty(&gl->gl_reclaim)) {
1620 gfs2_glock_hold(gl);
1621 list_add(&gl->gl_reclaim, &sdp->sd_reclaim_list);
1622 atomic_inc(&sdp->sd_reclaim_count);
1623 spin_unlock(&sdp->sd_reclaim_lock);
1624 wake_up(&sdp->sd_reclaim_wq);
1626 spin_unlock(&sdp->sd_reclaim_lock);
1630 * gfs2_reclaim_glock - process the next glock on the filesystem's reclaim list
1631 * @sdp: the filesystem
1633 * Called from gfs2_glockd() glock reclaim daemon, or when promoting a
1634 * different glock and we notice that there are a lot of glocks in the
1639 void gfs2_reclaim_glock(struct gfs2_sbd *sdp)
1641 struct gfs2_glock *gl;
1643 spin_lock(&sdp->sd_reclaim_lock);
1644 if (list_empty(&sdp->sd_reclaim_list)) {
1645 spin_unlock(&sdp->sd_reclaim_lock);
1648 gl = list_entry(sdp->sd_reclaim_list.next,
1649 struct gfs2_glock, gl_reclaim);
1650 list_del_init(&gl->gl_reclaim);
1651 spin_unlock(&sdp->sd_reclaim_lock);
1653 atomic_dec(&sdp->sd_reclaim_count);
1654 atomic_inc(&sdp->sd_reclaimed);
1656 if (gfs2_glmutex_trylock(gl)) {
1657 if (list_empty(&gl->gl_holders) &&
1658 gl->gl_state != LM_ST_UNLOCKED && demote_ok(gl))
1659 handle_callback(gl, LM_ST_UNLOCKED, 0, 0);
1660 gfs2_glmutex_unlock(gl);
1667 * examine_bucket - Call a function for glock in a hash bucket
1668 * @examiner: the function
1669 * @sdp: the filesystem
1670 * @bucket: the bucket
1672 * Returns: 1 if the bucket has entries
1675 static int examine_bucket(glock_examiner examiner, struct gfs2_sbd *sdp,
1678 struct gfs2_glock *gl, *prev = NULL;
1679 int has_entries = 0;
1680 struct hlist_head *head = &gl_hash_table[hash].hb_list;
1682 read_lock(gl_lock_addr(hash));
1683 /* Can't use hlist_for_each_entry - don't want prefetch here */
1684 if (hlist_empty(head))
1686 gl = list_entry(head->first, struct gfs2_glock, gl_list);
1688 if (!sdp || gl->gl_sbd == sdp) {
1689 gfs2_glock_hold(gl);
1690 read_unlock(gl_lock_addr(hash));
1692 gfs2_glock_put(prev);
1696 read_lock(gl_lock_addr(hash));
1698 if (gl->gl_list.next == NULL)
1700 gl = list_entry(gl->gl_list.next, struct gfs2_glock, gl_list);
1703 read_unlock(gl_lock_addr(hash));
1705 gfs2_glock_put(prev);
1711 * scan_glock - look at a glock and see if we can reclaim it
1712 * @gl: the glock to look at
1716 static void scan_glock(struct gfs2_glock *gl)
1718 if (gl->gl_ops == &gfs2_inode_glops && gl->gl_object)
1721 if (gfs2_glmutex_trylock(gl)) {
1722 if (list_empty(&gl->gl_holders) &&
1723 gl->gl_state != LM_ST_UNLOCKED && demote_ok(gl))
1725 gfs2_glmutex_unlock(gl);
1730 gfs2_glmutex_unlock(gl);
1731 gfs2_glock_schedule_for_reclaim(gl);
1735 * clear_glock - look at a glock and see if we can free it from glock cache
1736 * @gl: the glock to look at
1740 static void clear_glock(struct gfs2_glock *gl)
1742 struct gfs2_sbd *sdp = gl->gl_sbd;
1745 spin_lock(&sdp->sd_reclaim_lock);
1746 if (!list_empty(&gl->gl_reclaim)) {
1747 list_del_init(&gl->gl_reclaim);
1748 atomic_dec(&sdp->sd_reclaim_count);
1749 spin_unlock(&sdp->sd_reclaim_lock);
1750 released = gfs2_glock_put(gl);
1751 gfs2_assert(sdp, !released);
1753 spin_unlock(&sdp->sd_reclaim_lock);
1756 if (gfs2_glmutex_trylock(gl)) {
1757 if (list_empty(&gl->gl_holders) &&
1758 gl->gl_state != LM_ST_UNLOCKED)
1759 handle_callback(gl, LM_ST_UNLOCKED, 0, 0);
1760 gfs2_glmutex_unlock(gl);
1765 * gfs2_gl_hash_clear - Empty out the glock hash table
1766 * @sdp: the filesystem
1767 * @wait: wait until it's all gone
1769 * Called when unmounting the filesystem, or when inter-node lock manager
1770 * requests DROPLOCKS because it is running out of capacity.
1773 void gfs2_gl_hash_clear(struct gfs2_sbd *sdp, int wait)
1783 for (x = 0; x < GFS2_GL_HASH_SIZE; x++) {
1784 if (examine_bucket(clear_glock, sdp, x))
1791 if (time_after_eq(jiffies,
1792 t + gfs2_tune_get(sdp, gt_stall_secs) * HZ)) {
1793 fs_warn(sdp, "Unmount seems to be stalled. "
1794 "Dumping lock state...\n");
1795 gfs2_dump_lockstate(sdp);
1799 down_write(&gfs2_umount_flush_sem);
1800 invalidate_inodes(sdp->sd_vfs);
1801 up_write(&gfs2_umount_flush_sem);
1807 * Diagnostic routines to help debug distributed deadlock
1810 static void gfs2_print_symbol(struct glock_iter *gi, const char *fmt,
1811 unsigned long address)
1813 char buffer[KSYM_SYMBOL_LEN];
1815 sprint_symbol(buffer, address);
1816 print_dbg(gi, fmt, buffer);
1820 * dump_holder - print information about a glock holder
1821 * @str: a string naming the type of holder
1822 * @gh: the glock holder
1824 * Returns: 0 on success, -ENOBUFS when we run out of space
1827 static int dump_holder(struct glock_iter *gi, char *str,
1828 struct gfs2_holder *gh)
1831 struct task_struct *gh_owner;
1833 print_dbg(gi, " %s\n", str);
1834 if (gh->gh_owner_pid) {
1835 print_dbg(gi, " owner = %ld ",
1836 (long)pid_nr(gh->gh_owner_pid));
1837 gh_owner = pid_task(gh->gh_owner_pid, PIDTYPE_PID);
1839 print_dbg(gi, "(%s)\n", gh_owner->comm);
1841 print_dbg(gi, "(ended)\n");
1843 print_dbg(gi, " owner = -1\n");
1844 print_dbg(gi, " gh_state = %u\n", gh->gh_state);
1845 print_dbg(gi, " gh_flags =");
1846 for (x = 0; x < 32; x++)
1847 if (gh->gh_flags & (1 << x))
1848 print_dbg(gi, " %u", x);
1849 print_dbg(gi, " \n");
1850 print_dbg(gi, " error = %d\n", gh->gh_error);
1851 print_dbg(gi, " gh_iflags =");
1852 for (x = 0; x < 32; x++)
1853 if (test_bit(x, &gh->gh_iflags))
1854 print_dbg(gi, " %u", x);
1855 print_dbg(gi, " \n");
1856 gfs2_print_symbol(gi, " initialized at: %s\n", gh->gh_ip);
1862 * dump_inode - print information about an inode
1865 * Returns: 0 on success, -ENOBUFS when we run out of space
1868 static int dump_inode(struct glock_iter *gi, struct gfs2_inode *ip)
1872 print_dbg(gi, " Inode:\n");
1873 print_dbg(gi, " num = %llu/%llu\n",
1874 (unsigned long long)ip->i_no_formal_ino,
1875 (unsigned long long)ip->i_no_addr);
1876 print_dbg(gi, " type = %u\n", IF2DT(ip->i_inode.i_mode));
1877 print_dbg(gi, " i_flags =");
1878 for (x = 0; x < 32; x++)
1879 if (test_bit(x, &ip->i_flags))
1880 print_dbg(gi, " %u", x);
1881 print_dbg(gi, " \n");
1886 * dump_glock - print information about a glock
1888 * @count: where we are in the buffer
1890 * Returns: 0 on success, -ENOBUFS when we run out of space
1893 static int dump_glock(struct glock_iter *gi, struct gfs2_glock *gl)
1895 struct gfs2_holder *gh;
1897 int error = -ENOBUFS;
1898 struct task_struct *gl_owner;
1900 spin_lock(&gl->gl_spin);
1902 print_dbg(gi, "Glock 0x%p (%u, 0x%llx)\n", gl, gl->gl_name.ln_type,
1903 (unsigned long long)gl->gl_name.ln_number);
1904 print_dbg(gi, " gl_flags =");
1905 for (x = 0; x < 32; x++) {
1906 if (test_bit(x, &gl->gl_flags))
1907 print_dbg(gi, " %u", x);
1909 if (!test_bit(GLF_LOCK, &gl->gl_flags))
1910 print_dbg(gi, " (unlocked)");
1911 print_dbg(gi, " \n");
1912 print_dbg(gi, " gl_ref = %d\n", atomic_read(&gl->gl_ref));
1913 print_dbg(gi, " gl_state = %u\n", gl->gl_state);
1914 if (gl->gl_owner_pid) {
1915 gl_owner = pid_task(gl->gl_owner_pid, PIDTYPE_PID);
1917 print_dbg(gi, " gl_owner = pid %d (%s)\n",
1918 pid_nr(gl->gl_owner_pid), gl_owner->comm);
1920 print_dbg(gi, " gl_owner = %d (ended)\n",
1921 pid_nr(gl->gl_owner_pid));
1923 print_dbg(gi, " gl_owner = -1\n");
1924 print_dbg(gi, " gl_ip = %lu\n", gl->gl_ip);
1925 print_dbg(gi, " req_gh = %s\n", (gl->gl_req_gh) ? "yes" : "no");
1926 print_dbg(gi, " lvb_count = %d\n", atomic_read(&gl->gl_lvb_count));
1927 print_dbg(gi, " object = %s\n", (gl->gl_object) ? "yes" : "no");
1928 print_dbg(gi, " reclaim = %s\n",
1929 (list_empty(&gl->gl_reclaim)) ? "no" : "yes");
1931 print_dbg(gi, " aspace = 0x%p nrpages = %lu\n", gl->gl_aspace,
1932 gl->gl_aspace->i_mapping->nrpages);
1934 print_dbg(gi, " aspace = no\n");
1935 print_dbg(gi, " ail = %d\n", atomic_read(&gl->gl_ail_count));
1936 if (gl->gl_req_gh) {
1937 error = dump_holder(gi, "Request", gl->gl_req_gh);
1941 list_for_each_entry(gh, &gl->gl_holders, gh_list) {
1942 error = dump_holder(gi, "Holder", gh);
1946 list_for_each_entry(gh, &gl->gl_waiters1, gh_list) {
1947 error = dump_holder(gi, "Waiter1", gh);
1951 list_for_each_entry(gh, &gl->gl_waiters3, gh_list) {
1952 error = dump_holder(gi, "Waiter3", gh);
1956 if (test_bit(GLF_DEMOTE, &gl->gl_flags)) {
1957 print_dbg(gi, " Demotion req to state %u (%llu uS ago)\n",
1958 gl->gl_demote_state, (unsigned long long)
1959 (jiffies - gl->gl_demote_time)*(1000000/HZ));
1961 if (gl->gl_ops == &gfs2_inode_glops && gl->gl_object) {
1962 if (!test_bit(GLF_LOCK, &gl->gl_flags) &&
1963 list_empty(&gl->gl_holders)) {
1964 error = dump_inode(gi, gl->gl_object);
1969 print_dbg(gi, " Inode: busy\n");
1976 spin_unlock(&gl->gl_spin);
1981 * gfs2_dump_lockstate - print out the current lockstate
1982 * @sdp: the filesystem
1983 * @ub: the buffer to copy the information into
1985 * If @ub is NULL, dump the lockstate to the console.
1989 static int gfs2_dump_lockstate(struct gfs2_sbd *sdp)
1991 struct gfs2_glock *gl;
1992 struct hlist_node *h;
1996 for (x = 0; x < GFS2_GL_HASH_SIZE; x++) {
1998 read_lock(gl_lock_addr(x));
2000 hlist_for_each_entry(gl, h, &gl_hash_table[x].hb_list, gl_list) {
2001 if (gl->gl_sbd != sdp)
2004 error = dump_glock(NULL, gl);
2009 read_unlock(gl_lock_addr(x));
2020 * gfs2_scand - Look for cached glocks and inodes to toss from memory
2021 * @sdp: Pointer to GFS2 superblock
2023 * One of these daemons runs, finding candidates to add to sd_reclaim_list.
2027 static int gfs2_scand(void *data)
2032 while (!kthread_should_stop()) {
2033 for (x = 0; x < GFS2_GL_HASH_SIZE; x++)
2034 examine_bucket(scan_glock, NULL, x);
2035 if (freezing(current))
2040 schedule_timeout_interruptible(delay * HZ);
2048 int __init gfs2_glock_init(void)
2051 for(i = 0; i < GFS2_GL_HASH_SIZE; i++) {
2052 INIT_HLIST_HEAD(&gl_hash_table[i].hb_list);
2054 #ifdef GL_HASH_LOCK_SZ
2055 for(i = 0; i < GL_HASH_LOCK_SZ; i++) {
2056 rwlock_init(&gl_hash_locks[i]);
2060 scand_process = kthread_run(gfs2_scand, NULL, "gfs2_scand");
2061 if (IS_ERR(scand_process))
2062 return PTR_ERR(scand_process);
2064 glock_workqueue = create_workqueue("glock_workqueue");
2065 if (IS_ERR(glock_workqueue)) {
2066 kthread_stop(scand_process);
2067 return PTR_ERR(glock_workqueue);
2073 void gfs2_glock_exit(void)
2075 destroy_workqueue(glock_workqueue);
2076 kthread_stop(scand_process);
2079 module_param(scand_secs, uint, S_IRUGO|S_IWUSR);
2080 MODULE_PARM_DESC(scand_secs, "The number of seconds between scand runs");
2082 static int gfs2_glock_iter_next(struct glock_iter *gi)
2084 struct gfs2_glock *gl;
2087 read_lock(gl_lock_addr(gi->hash));
2090 gi->gl = hlist_entry(gl->gl_list.next,
2091 struct gfs2_glock, gl_list);
2093 gfs2_glock_hold(gi->gl);
2095 read_unlock(gl_lock_addr(gi->hash));
2098 if (gl && gi->gl == NULL)
2100 while(gi->gl == NULL) {
2101 if (gi->hash >= GFS2_GL_HASH_SIZE)
2103 read_lock(gl_lock_addr(gi->hash));
2104 gi->gl = hlist_entry(gl_hash_table[gi->hash].hb_list.first,
2105 struct gfs2_glock, gl_list);
2107 gfs2_glock_hold(gi->gl);
2108 read_unlock(gl_lock_addr(gi->hash));
2112 if (gi->sdp != gi->gl->gl_sbd)
2118 static void gfs2_glock_iter_free(struct glock_iter *gi)
2121 gfs2_glock_put(gi->gl);
2125 static struct glock_iter *gfs2_glock_iter_init(struct gfs2_sbd *sdp)
2127 struct glock_iter *gi;
2129 gi = kmalloc(sizeof (*gi), GFP_KERNEL);
2137 memset(gi->string, 0, sizeof(gi->string));
2139 if (gfs2_glock_iter_next(gi)) {
2140 gfs2_glock_iter_free(gi);
2147 static void *gfs2_glock_seq_start(struct seq_file *file, loff_t *pos)
2149 struct glock_iter *gi;
2152 gi = gfs2_glock_iter_init(file->private);
2157 if (gfs2_glock_iter_next(gi)) {
2158 gfs2_glock_iter_free(gi);
2166 static void *gfs2_glock_seq_next(struct seq_file *file, void *iter_ptr,
2169 struct glock_iter *gi = iter_ptr;
2173 if (gfs2_glock_iter_next(gi)) {
2174 gfs2_glock_iter_free(gi);
2181 static void gfs2_glock_seq_stop(struct seq_file *file, void *iter_ptr)
2183 struct glock_iter *gi = iter_ptr;
2185 gfs2_glock_iter_free(gi);
2188 static int gfs2_glock_seq_show(struct seq_file *file, void *iter_ptr)
2190 struct glock_iter *gi = iter_ptr;
2193 dump_glock(gi, gi->gl);
2198 static const struct seq_operations gfs2_glock_seq_ops = {
2199 .start = gfs2_glock_seq_start,
2200 .next = gfs2_glock_seq_next,
2201 .stop = gfs2_glock_seq_stop,
2202 .show = gfs2_glock_seq_show,
2205 static int gfs2_debugfs_open(struct inode *inode, struct file *file)
2207 struct seq_file *seq;
2210 ret = seq_open(file, &gfs2_glock_seq_ops);
2214 seq = file->private_data;
2215 seq->private = inode->i_private;
2220 static const struct file_operations gfs2_debug_fops = {
2221 .owner = THIS_MODULE,
2222 .open = gfs2_debugfs_open,
2224 .llseek = seq_lseek,
2225 .release = seq_release
2228 int gfs2_create_debugfs_file(struct gfs2_sbd *sdp)
2230 sdp->debugfs_dir = debugfs_create_dir(sdp->sd_table_name, gfs2_root);
2231 if (!sdp->debugfs_dir)
2233 sdp->debugfs_dentry_glocks = debugfs_create_file("glocks",
2235 sdp->debugfs_dir, sdp,
2237 if (!sdp->debugfs_dentry_glocks)
2243 void gfs2_delete_debugfs_file(struct gfs2_sbd *sdp)
2245 if (sdp && sdp->debugfs_dir) {
2246 if (sdp->debugfs_dentry_glocks) {
2247 debugfs_remove(sdp->debugfs_dentry_glocks);
2248 sdp->debugfs_dentry_glocks = NULL;
2250 debugfs_remove(sdp->debugfs_dir);
2251 sdp->debugfs_dir = NULL;
2255 int gfs2_register_debugfs(void)
2257 gfs2_root = debugfs_create_dir("gfs2", NULL);
2258 return gfs2_root ? 0 : -ENOMEM;
2261 void gfs2_unregister_debugfs(void)
2263 debugfs_remove(gfs2_root);