2 * Copyright (C) Sistina Software, Inc. 1997-2003 All rights reserved.
3 * Copyright (C) 2004-2007 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>
45 struct gfs2_gl_hash_bucket
{
46 struct hlist_head hb_list
;
50 int hash
; /* hash bucket index */
51 struct gfs2_sbd
*sdp
; /* incore superblock */
52 struct gfs2_glock
*gl
; /* current glock struct */
53 struct seq_file
*seq
; /* sequence file for debugfs */
54 char string
[512]; /* scratch space */
57 typedef void (*glock_examiner
) (struct gfs2_glock
* gl
);
59 static int gfs2_dump_lockstate(struct gfs2_sbd
*sdp
);
60 static int dump_glock(struct glock_iter
*gi
, struct gfs2_glock
*gl
);
61 static void gfs2_glock_xmote_th(struct gfs2_glock
*gl
, struct gfs2_holder
*gh
);
62 static void gfs2_glock_drop_th(struct gfs2_glock
*gl
);
63 static void run_queue(struct gfs2_glock
*gl
);
65 static DECLARE_RWSEM(gfs2_umount_flush_sem
);
66 static struct dentry
*gfs2_root
;
67 static struct task_struct
*scand_process
;
68 static unsigned int scand_secs
= 5;
69 static struct workqueue_struct
*glock_workqueue
;
71 #define GFS2_GL_HASH_SHIFT 15
72 #define GFS2_GL_HASH_SIZE (1 << GFS2_GL_HASH_SHIFT)
73 #define GFS2_GL_HASH_MASK (GFS2_GL_HASH_SIZE - 1)
75 static struct gfs2_gl_hash_bucket gl_hash_table
[GFS2_GL_HASH_SIZE
];
76 static struct dentry
*gfs2_root
;
79 * Despite what you might think, the numbers below are not arbitrary :-)
80 * They are taken from the ipv4 routing hash code, which is well tested
81 * and thus should be nearly optimal. Later on we might tweek the numbers
82 * but for now this should be fine.
84 * The reason for putting the locks in a separate array from the list heads
85 * is that we can have fewer locks than list heads and save memory. We use
86 * the same hash function for both, but with a different hash mask.
88 #if defined(CONFIG_SMP) || defined(CONFIG_DEBUG_SPINLOCK) || \
89 defined(CONFIG_PROVE_LOCKING)
92 # define GL_HASH_LOCK_SZ 256
95 # define GL_HASH_LOCK_SZ 4096
97 # define GL_HASH_LOCK_SZ 2048
99 # define GL_HASH_LOCK_SZ 1024
101 # define GL_HASH_LOCK_SZ 512
103 # define GL_HASH_LOCK_SZ 256
107 /* We never want more locks than chains */
108 #if GFS2_GL_HASH_SIZE < GL_HASH_LOCK_SZ
109 # undef GL_HASH_LOCK_SZ
110 # define GL_HASH_LOCK_SZ GFS2_GL_HASH_SIZE
113 static rwlock_t gl_hash_locks
[GL_HASH_LOCK_SZ
];
115 static inline rwlock_t
*gl_lock_addr(unsigned int x
)
117 return &gl_hash_locks
[x
& (GL_HASH_LOCK_SZ
-1)];
119 #else /* not SMP, so no spinlocks required */
120 static inline rwlock_t
*gl_lock_addr(unsigned int x
)
127 * relaxed_state_ok - is a requested lock compatible with the current lock mode?
128 * @actual: the current state of the lock
129 * @requested: the lock state that was requested by the caller
130 * @flags: the modifier flags passed in by the caller
132 * Returns: 1 if the locks are compatible, 0 otherwise
135 static inline int relaxed_state_ok(unsigned int actual
, unsigned requested
,
138 if (actual
== requested
)
141 if (flags
& GL_EXACT
)
144 if (actual
== LM_ST_EXCLUSIVE
&& requested
== LM_ST_SHARED
)
147 if (actual
!= LM_ST_UNLOCKED
&& (flags
& LM_FLAG_ANY
))
154 * gl_hash() - Turn glock number into hash bucket number
155 * @lock: The glock number
157 * Returns: The number of the corresponding hash bucket
160 static unsigned int gl_hash(const struct gfs2_sbd
*sdp
,
161 const struct lm_lockname
*name
)
165 h
= jhash(&name
->ln_number
, sizeof(u64
), 0);
166 h
= jhash(&name
->ln_type
, sizeof(unsigned int), h
);
167 h
= jhash(&sdp
, sizeof(struct gfs2_sbd
*), h
);
168 h
&= GFS2_GL_HASH_MASK
;
174 * glock_free() - Perform a few checks and then release struct gfs2_glock
175 * @gl: The glock to release
177 * Also calls lock module to release its internal structure for this glock.
181 static void glock_free(struct gfs2_glock
*gl
)
183 struct gfs2_sbd
*sdp
= gl
->gl_sbd
;
184 struct inode
*aspace
= gl
->gl_aspace
;
186 gfs2_lm_put_lock(sdp
, 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 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
);
297 * gfs2_glock_get() - Get a glock, or create one if one doesn't exist
298 * @sdp: The GFS2 superblock
299 * @number: the lock number
300 * @glops: The glock_operations to use
301 * @create: If 0, don't create the glock if it doesn't exist
302 * @glp: the glock is returned here
304 * This does not lock a glock, just finds/creates structures for one.
309 int gfs2_glock_get(struct gfs2_sbd
*sdp
, u64 number
,
310 const struct gfs2_glock_operations
*glops
, int create
,
311 struct gfs2_glock
**glp
)
313 struct lm_lockname name
= { .ln_number
= number
, .ln_type
= glops
->go_type
};
314 struct gfs2_glock
*gl
, *tmp
;
315 unsigned int hash
= gl_hash(sdp
, &name
);
318 read_lock(gl_lock_addr(hash
));
319 gl
= search_bucket(hash
, sdp
, &name
);
320 read_unlock(gl_lock_addr(hash
));
327 gl
= kmem_cache_alloc(gfs2_glock_cachep
, GFP_KERNEL
);
333 atomic_set(&gl
->gl_ref
, 1);
334 gl
->gl_state
= LM_ST_UNLOCKED
;
335 gl
->gl_demote_state
= LM_ST_EXCLUSIVE
;
337 gl
->gl_owner_pid
= 0;
340 gl
->gl_req_gh
= NULL
;
341 gl
->gl_req_bh
= NULL
;
343 gl
->gl_stamp
= jiffies
;
344 gl
->gl_tchange
= jiffies
;
345 gl
->gl_object
= NULL
;
347 gl
->gl_aspace
= NULL
;
348 INIT_DELAYED_WORK(&gl
->gl_work
, glock_work_func
);
350 /* If this glock protects actual on-disk data or metadata blocks,
351 create a VFS inode to manage the pages/buffers holding them. */
352 if (glops
== &gfs2_inode_glops
|| glops
== &gfs2_rgrp_glops
) {
353 gl
->gl_aspace
= gfs2_aspace_get(sdp
);
354 if (!gl
->gl_aspace
) {
360 error
= gfs2_lm_get_lock(sdp
, &name
, &gl
->gl_lock
);
364 write_lock(gl_lock_addr(hash
));
365 tmp
= search_bucket(hash
, sdp
, &name
);
367 write_unlock(gl_lock_addr(hash
));
371 hlist_add_head(&gl
->gl_list
, &gl_hash_table
[hash
].hb_list
);
372 write_unlock(gl_lock_addr(hash
));
381 gfs2_aspace_put(gl
->gl_aspace
);
383 kmem_cache_free(gfs2_glock_cachep
, gl
);
388 * gfs2_holder_init - initialize a struct gfs2_holder in the default way
390 * @state: the state we're requesting
391 * @flags: the modifier flags
392 * @gh: the holder structure
396 void gfs2_holder_init(struct gfs2_glock
*gl
, unsigned int state
, unsigned flags
,
397 struct gfs2_holder
*gh
)
399 INIT_LIST_HEAD(&gh
->gh_list
);
401 gh
->gh_ip
= (unsigned long)__builtin_return_address(0);
402 gh
->gh_owner_pid
= get_pid(task_pid(current
));
403 gh
->gh_state
= state
;
404 gh
->gh_flags
= flags
;
411 * gfs2_holder_reinit - reinitialize a struct gfs2_holder so we can requeue it
412 * @state: the state we're requesting
413 * @flags: the modifier flags
414 * @gh: the holder structure
416 * Don't mess with the glock.
420 void gfs2_holder_reinit(unsigned int state
, unsigned flags
, struct gfs2_holder
*gh
)
422 gh
->gh_state
= state
;
423 gh
->gh_flags
= flags
;
425 gh
->gh_ip
= (unsigned long)__builtin_return_address(0);
429 * gfs2_holder_uninit - uninitialize a holder structure (drop glock reference)
430 * @gh: the holder structure
434 void gfs2_holder_uninit(struct gfs2_holder
*gh
)
436 put_pid(gh
->gh_owner_pid
);
437 gfs2_glock_put(gh
->gh_gl
);
442 static void gfs2_holder_wake(struct gfs2_holder
*gh
)
444 clear_bit(HIF_WAIT
, &gh
->gh_iflags
);
445 smp_mb__after_clear_bit();
446 wake_up_bit(&gh
->gh_iflags
, HIF_WAIT
);
449 static int just_schedule(void *word
)
455 static void wait_on_holder(struct gfs2_holder
*gh
)
458 wait_on_bit(&gh
->gh_iflags
, HIF_WAIT
, just_schedule
, TASK_UNINTERRUPTIBLE
);
461 static void gfs2_demote_wake(struct gfs2_glock
*gl
)
463 gl
->gl_demote_state
= LM_ST_EXCLUSIVE
;
464 clear_bit(GLF_DEMOTE
, &gl
->gl_flags
);
465 smp_mb__after_clear_bit();
466 wake_up_bit(&gl
->gl_flags
, GLF_DEMOTE
);
469 static void wait_on_demote(struct gfs2_glock
*gl
)
472 wait_on_bit(&gl
->gl_flags
, GLF_DEMOTE
, just_schedule
, TASK_UNINTERRUPTIBLE
);
476 * rq_mutex - process a mutex request in the queue
477 * @gh: the glock holder
479 * Returns: 1 if the queue is blocked
482 static int rq_mutex(struct gfs2_holder
*gh
)
484 struct gfs2_glock
*gl
= gh
->gh_gl
;
486 list_del_init(&gh
->gh_list
);
487 /* gh->gh_error never examined. */
488 set_bit(GLF_LOCK
, &gl
->gl_flags
);
489 clear_bit(HIF_WAIT
, &gh
->gh_iflags
);
491 wake_up_bit(&gh
->gh_iflags
, HIF_WAIT
);
497 * rq_promote - process a promote request in the queue
498 * @gh: the glock holder
500 * Acquire a new inter-node lock, or change a lock state to more restrictive.
502 * Returns: 1 if the queue is blocked
505 static int rq_promote(struct gfs2_holder
*gh
)
507 struct gfs2_glock
*gl
= gh
->gh_gl
;
509 if (!relaxed_state_ok(gl
->gl_state
, gh
->gh_state
, gh
->gh_flags
)) {
510 if (list_empty(&gl
->gl_holders
)) {
512 set_bit(GLF_LOCK
, &gl
->gl_flags
);
513 spin_unlock(&gl
->gl_spin
);
514 gfs2_glock_xmote_th(gh
->gh_gl
, gh
);
515 spin_lock(&gl
->gl_spin
);
520 if (list_empty(&gl
->gl_holders
)) {
521 set_bit(HIF_FIRST
, &gh
->gh_iflags
);
522 set_bit(GLF_LOCK
, &gl
->gl_flags
);
524 struct gfs2_holder
*next_gh
;
525 if (gh
->gh_state
== LM_ST_EXCLUSIVE
)
527 next_gh
= list_entry(gl
->gl_holders
.next
, struct gfs2_holder
,
529 if (next_gh
->gh_state
== LM_ST_EXCLUSIVE
)
533 list_move_tail(&gh
->gh_list
, &gl
->gl_holders
);
535 set_bit(HIF_HOLDER
, &gh
->gh_iflags
);
537 gfs2_holder_wake(gh
);
543 * rq_demote - process a demote request in the queue
544 * @gh: the glock holder
546 * Returns: 1 if the queue is blocked
549 static int rq_demote(struct gfs2_glock
*gl
)
551 if (!list_empty(&gl
->gl_holders
))
554 if (gl
->gl_state
== gl
->gl_demote_state
||
555 gl
->gl_state
== LM_ST_UNLOCKED
) {
556 gfs2_demote_wake(gl
);
560 set_bit(GLF_LOCK
, &gl
->gl_flags
);
561 set_bit(GLF_DEMOTE_IN_PROGRESS
, &gl
->gl_flags
);
563 if (gl
->gl_demote_state
== LM_ST_UNLOCKED
||
564 gl
->gl_state
!= LM_ST_EXCLUSIVE
) {
565 spin_unlock(&gl
->gl_spin
);
566 gfs2_glock_drop_th(gl
);
568 spin_unlock(&gl
->gl_spin
);
569 gfs2_glock_xmote_th(gl
, NULL
);
572 spin_lock(&gl
->gl_spin
);
573 clear_bit(GLF_DEMOTE_IN_PROGRESS
, &gl
->gl_flags
);
579 * run_queue - process holder structures on a glock
583 static void run_queue(struct gfs2_glock
*gl
)
585 struct gfs2_holder
*gh
;
589 if (test_bit(GLF_LOCK
, &gl
->gl_flags
))
592 if (!list_empty(&gl
->gl_waiters1
)) {
593 gh
= list_entry(gl
->gl_waiters1
.next
,
594 struct gfs2_holder
, gh_list
);
595 blocked
= rq_mutex(gh
);
596 } else if (test_bit(GLF_DEMOTE
, &gl
->gl_flags
)) {
597 blocked
= rq_demote(gl
);
598 if (gl
->gl_waiters2
&& !blocked
) {
599 set_bit(GLF_DEMOTE
, &gl
->gl_flags
);
600 gl
->gl_demote_state
= LM_ST_UNLOCKED
;
603 } else if (!list_empty(&gl
->gl_waiters3
)) {
604 gh
= list_entry(gl
->gl_waiters3
.next
,
605 struct gfs2_holder
, gh_list
);
606 blocked
= rq_promote(gh
);
616 * gfs2_glmutex_lock - acquire a local lock on a glock
619 * Gives caller exclusive access to manipulate a glock structure.
622 static void gfs2_glmutex_lock(struct gfs2_glock
*gl
)
624 spin_lock(&gl
->gl_spin
);
625 if (test_and_set_bit(GLF_LOCK
, &gl
->gl_flags
)) {
626 struct gfs2_holder gh
;
628 gfs2_holder_init(gl
, 0, 0, &gh
);
629 set_bit(HIF_WAIT
, &gh
.gh_iflags
);
630 list_add_tail(&gh
.gh_list
, &gl
->gl_waiters1
);
631 spin_unlock(&gl
->gl_spin
);
633 gfs2_holder_uninit(&gh
);
635 gl
->gl_owner_pid
= current
->pid
;
636 gl
->gl_ip
= (unsigned long)__builtin_return_address(0);
637 spin_unlock(&gl
->gl_spin
);
642 * gfs2_glmutex_trylock - try to acquire a local lock on a glock
645 * Returns: 1 if the glock is acquired
648 static int gfs2_glmutex_trylock(struct gfs2_glock
*gl
)
652 spin_lock(&gl
->gl_spin
);
653 if (test_and_set_bit(GLF_LOCK
, &gl
->gl_flags
)) {
656 gl
->gl_owner_pid
= current
->pid
;
657 gl
->gl_ip
= (unsigned long)__builtin_return_address(0);
659 spin_unlock(&gl
->gl_spin
);
665 * gfs2_glmutex_unlock - release a local lock on a glock
670 static void gfs2_glmutex_unlock(struct gfs2_glock
*gl
)
672 spin_lock(&gl
->gl_spin
);
673 clear_bit(GLF_LOCK
, &gl
->gl_flags
);
674 gl
->gl_owner_pid
= 0;
677 spin_unlock(&gl
->gl_spin
);
681 * handle_callback - process a demote request
683 * @state: the state the caller wants us to change to
685 * There are only two requests that we are going to see in actual
686 * practise: LM_ST_SHARED and LM_ST_UNLOCKED
689 static void handle_callback(struct gfs2_glock
*gl
, unsigned int state
,
690 int remote
, unsigned long delay
)
692 int bit
= delay
? GLF_PENDING_DEMOTE
: GLF_DEMOTE
;
694 spin_lock(&gl
->gl_spin
);
695 set_bit(bit
, &gl
->gl_flags
);
696 if (gl
->gl_demote_state
== LM_ST_EXCLUSIVE
) {
697 gl
->gl_demote_state
= state
;
698 gl
->gl_demote_time
= jiffies
;
699 if (remote
&& gl
->gl_ops
->go_type
== LM_TYPE_IOPEN
&&
701 gfs2_glock_schedule_for_reclaim(gl
);
702 spin_unlock(&gl
->gl_spin
);
705 } else if (gl
->gl_demote_state
!= LM_ST_UNLOCKED
&&
706 gl
->gl_demote_state
!= state
) {
707 if (test_bit(GLF_DEMOTE_IN_PROGRESS
, &gl
->gl_flags
))
710 gl
->gl_demote_state
= LM_ST_UNLOCKED
;
712 spin_unlock(&gl
->gl_spin
);
716 * state_change - record that the glock is now in a different state
718 * @new_state the new state
722 static void state_change(struct gfs2_glock
*gl
, unsigned int new_state
)
726 held1
= (gl
->gl_state
!= LM_ST_UNLOCKED
);
727 held2
= (new_state
!= LM_ST_UNLOCKED
);
729 if (held1
!= held2
) {
736 gl
->gl_state
= new_state
;
737 gl
->gl_tchange
= jiffies
;
741 * xmote_bh - Called after the lock module is done acquiring a lock
742 * @gl: The glock in question
743 * @ret: the int returned from the lock module
747 static void xmote_bh(struct gfs2_glock
*gl
, unsigned int ret
)
749 struct gfs2_sbd
*sdp
= gl
->gl_sbd
;
750 const struct gfs2_glock_operations
*glops
= gl
->gl_ops
;
751 struct gfs2_holder
*gh
= gl
->gl_req_gh
;
752 int prev_state
= gl
->gl_state
;
755 gfs2_assert_warn(sdp
, test_bit(GLF_LOCK
, &gl
->gl_flags
));
756 gfs2_assert_warn(sdp
, list_empty(&gl
->gl_holders
));
757 gfs2_assert_warn(sdp
, !(ret
& LM_OUT_ASYNC
));
759 state_change(gl
, ret
& LM_OUT_ST_MASK
);
761 if (prev_state
!= LM_ST_UNLOCKED
&& !(ret
& LM_OUT_CACHEABLE
)) {
763 glops
->go_inval(gl
, DIO_METADATA
);
764 } else if (gl
->gl_state
== LM_ST_DEFERRED
) {
765 /* We might not want to do this here.
766 Look at moving to the inode glops. */
768 glops
->go_inval(gl
, 0);
771 /* Deal with each possible exit condition */
774 gl
->gl_stamp
= jiffies
;
775 if (ret
& LM_OUT_CANCELED
) {
778 spin_lock(&gl
->gl_spin
);
779 if (gl
->gl_state
!= gl
->gl_demote_state
) {
780 gl
->gl_req_bh
= NULL
;
781 spin_unlock(&gl
->gl_spin
);
782 gfs2_glock_drop_th(gl
);
786 gfs2_demote_wake(gl
);
787 spin_unlock(&gl
->gl_spin
);
790 spin_lock(&gl
->gl_spin
);
791 list_del_init(&gh
->gh_list
);
793 if (unlikely(test_bit(SDF_SHUTDOWN
, &sdp
->sd_flags
)))
795 gh
->gh_error
= GLR_CANCELED
;
796 if (ret
& LM_OUT_CANCELED
)
798 if (relaxed_state_ok(gl
->gl_state
, gh
->gh_state
, gh
->gh_flags
)) {
799 list_add_tail(&gh
->gh_list
, &gl
->gl_holders
);
801 set_bit(HIF_HOLDER
, &gh
->gh_iflags
);
802 set_bit(HIF_FIRST
, &gh
->gh_iflags
);
806 gh
->gh_error
= GLR_TRYFAILED
;
807 if (gh
->gh_flags
& (LM_FLAG_TRY
| LM_FLAG_TRY_1CB
))
809 gh
->gh_error
= -EINVAL
;
810 if (gfs2_assert_withdraw(sdp
, 0) == -1)
811 fs_err(sdp
, "ret = 0x%.8X\n", ret
);
813 spin_unlock(&gl
->gl_spin
);
816 if (glops
->go_xmote_bh
)
817 glops
->go_xmote_bh(gl
);
820 spin_lock(&gl
->gl_spin
);
821 gl
->gl_req_gh
= NULL
;
822 gl
->gl_req_bh
= NULL
;
823 clear_bit(GLF_LOCK
, &gl
->gl_flags
);
824 spin_unlock(&gl
->gl_spin
);
830 gfs2_holder_wake(gh
);
834 * gfs2_glock_xmote_th - Call into the lock module to acquire or change a glock
835 * @gl: The glock in question
836 * @state: the requested state
837 * @flags: modifier flags to the lock call
841 static void gfs2_glock_xmote_th(struct gfs2_glock
*gl
, struct gfs2_holder
*gh
)
843 struct gfs2_sbd
*sdp
= gl
->gl_sbd
;
844 int flags
= gh
? gh
->gh_flags
: 0;
845 unsigned state
= gh
? gh
->gh_state
: gl
->gl_demote_state
;
846 const struct gfs2_glock_operations
*glops
= gl
->gl_ops
;
847 int lck_flags
= flags
& (LM_FLAG_TRY
| LM_FLAG_TRY_1CB
|
848 LM_FLAG_NOEXP
| LM_FLAG_ANY
|
850 unsigned int lck_ret
;
852 if (glops
->go_xmote_th
)
853 glops
->go_xmote_th(gl
);
855 gfs2_assert_warn(sdp
, test_bit(GLF_LOCK
, &gl
->gl_flags
));
856 gfs2_assert_warn(sdp
, list_empty(&gl
->gl_holders
));
857 gfs2_assert_warn(sdp
, state
!= LM_ST_UNLOCKED
);
858 gfs2_assert_warn(sdp
, state
!= gl
->gl_state
);
861 gl
->gl_req_bh
= xmote_bh
;
863 lck_ret
= gfs2_lm_lock(sdp
, gl
->gl_lock
, gl
->gl_state
, state
, lck_flags
);
865 if (gfs2_assert_withdraw(sdp
, !(lck_ret
& LM_OUT_ERROR
)))
868 if (lck_ret
& LM_OUT_ASYNC
)
869 gfs2_assert_warn(sdp
, lck_ret
== LM_OUT_ASYNC
);
871 xmote_bh(gl
, lck_ret
);
875 * drop_bh - Called after a lock module unlock completes
877 * @ret: the return status
879 * Doesn't wake up the process waiting on the struct gfs2_holder (if any)
880 * Doesn't drop the reference on the glock the top half took out
884 static void drop_bh(struct gfs2_glock
*gl
, unsigned int ret
)
886 struct gfs2_sbd
*sdp
= gl
->gl_sbd
;
887 const struct gfs2_glock_operations
*glops
= gl
->gl_ops
;
888 struct gfs2_holder
*gh
= gl
->gl_req_gh
;
890 gfs2_assert_warn(sdp
, test_bit(GLF_LOCK
, &gl
->gl_flags
));
891 gfs2_assert_warn(sdp
, list_empty(&gl
->gl_holders
));
892 gfs2_assert_warn(sdp
, !ret
);
894 state_change(gl
, LM_ST_UNLOCKED
);
897 glops
->go_inval(gl
, DIO_METADATA
);
900 spin_lock(&gl
->gl_spin
);
901 list_del_init(&gh
->gh_list
);
903 spin_unlock(&gl
->gl_spin
);
906 spin_lock(&gl
->gl_spin
);
907 gfs2_demote_wake(gl
);
908 gl
->gl_req_gh
= NULL
;
909 gl
->gl_req_bh
= NULL
;
910 clear_bit(GLF_LOCK
, &gl
->gl_flags
);
911 spin_unlock(&gl
->gl_spin
);
916 gfs2_holder_wake(gh
);
920 * gfs2_glock_drop_th - call into the lock module to unlock a lock
925 static void gfs2_glock_drop_th(struct gfs2_glock
*gl
)
927 struct gfs2_sbd
*sdp
= gl
->gl_sbd
;
928 const struct gfs2_glock_operations
*glops
= gl
->gl_ops
;
931 if (glops
->go_xmote_th
)
932 glops
->go_xmote_th(gl
);
934 gfs2_assert_warn(sdp
, test_bit(GLF_LOCK
, &gl
->gl_flags
));
935 gfs2_assert_warn(sdp
, list_empty(&gl
->gl_holders
));
936 gfs2_assert_warn(sdp
, gl
->gl_state
!= LM_ST_UNLOCKED
);
939 gl
->gl_req_bh
= drop_bh
;
941 ret
= gfs2_lm_unlock(sdp
, gl
->gl_lock
, gl
->gl_state
);
943 if (gfs2_assert_withdraw(sdp
, !(ret
& LM_OUT_ERROR
)))
949 gfs2_assert_warn(sdp
, ret
== LM_OUT_ASYNC
);
953 * do_cancels - cancel requests for locks stuck waiting on an expire flag
954 * @gh: the LM_FLAG_PRIORITY holder waiting to acquire the lock
956 * Don't cancel GL_NOCANCEL requests.
959 static void do_cancels(struct gfs2_holder
*gh
)
961 struct gfs2_glock
*gl
= gh
->gh_gl
;
963 spin_lock(&gl
->gl_spin
);
965 while (gl
->gl_req_gh
!= gh
&&
966 !test_bit(HIF_HOLDER
, &gh
->gh_iflags
) &&
967 !list_empty(&gh
->gh_list
)) {
968 if (gl
->gl_req_bh
&& !(gl
->gl_req_gh
&&
969 (gl
->gl_req_gh
->gh_flags
& GL_NOCANCEL
))) {
970 spin_unlock(&gl
->gl_spin
);
971 gfs2_lm_cancel(gl
->gl_sbd
, gl
->gl_lock
);
973 spin_lock(&gl
->gl_spin
);
975 spin_unlock(&gl
->gl_spin
);
977 spin_lock(&gl
->gl_spin
);
981 spin_unlock(&gl
->gl_spin
);
985 * glock_wait_internal - wait on a glock acquisition
986 * @gh: the glock holder
988 * Returns: 0 on success
991 static int glock_wait_internal(struct gfs2_holder
*gh
)
993 struct gfs2_glock
*gl
= gh
->gh_gl
;
994 struct gfs2_sbd
*sdp
= gl
->gl_sbd
;
995 const struct gfs2_glock_operations
*glops
= gl
->gl_ops
;
997 if (test_bit(HIF_ABORTED
, &gh
->gh_iflags
))
1000 if (gh
->gh_flags
& (LM_FLAG_TRY
| LM_FLAG_TRY_1CB
)) {
1001 spin_lock(&gl
->gl_spin
);
1002 if (gl
->gl_req_gh
!= gh
&&
1003 !test_bit(HIF_HOLDER
, &gh
->gh_iflags
) &&
1004 !list_empty(&gh
->gh_list
)) {
1005 list_del_init(&gh
->gh_list
);
1006 gh
->gh_error
= GLR_TRYFAILED
;
1008 spin_unlock(&gl
->gl_spin
);
1009 return gh
->gh_error
;
1011 spin_unlock(&gl
->gl_spin
);
1014 if (gh
->gh_flags
& LM_FLAG_PRIORITY
)
1019 return gh
->gh_error
;
1021 gfs2_assert_withdraw(sdp
, test_bit(HIF_HOLDER
, &gh
->gh_iflags
));
1022 gfs2_assert_withdraw(sdp
, relaxed_state_ok(gl
->gl_state
, gh
->gh_state
,
1025 if (test_bit(HIF_FIRST
, &gh
->gh_iflags
)) {
1026 gfs2_assert_warn(sdp
, test_bit(GLF_LOCK
, &gl
->gl_flags
));
1028 if (glops
->go_lock
) {
1029 gh
->gh_error
= glops
->go_lock(gh
);
1031 spin_lock(&gl
->gl_spin
);
1032 list_del_init(&gh
->gh_list
);
1033 spin_unlock(&gl
->gl_spin
);
1037 spin_lock(&gl
->gl_spin
);
1038 gl
->gl_req_gh
= NULL
;
1039 gl
->gl_req_bh
= NULL
;
1040 clear_bit(GLF_LOCK
, &gl
->gl_flags
);
1042 spin_unlock(&gl
->gl_spin
);
1045 return gh
->gh_error
;
1048 static inline struct gfs2_holder
*
1049 find_holder_by_owner(struct list_head
*head
, struct pid
*pid
)
1051 struct gfs2_holder
*gh
;
1053 list_for_each_entry(gh
, head
, gh_list
) {
1054 if (gh
->gh_owner_pid
== pid
)
1061 static void print_dbg(struct glock_iter
*gi
, const char *fmt
, ...)
1065 va_start(args
, fmt
);
1067 vsprintf(gi
->string
, fmt
, args
);
1068 seq_printf(gi
->seq
, gi
->string
);
1076 * add_to_queue - Add a holder to the wait queue (but look for recursion)
1077 * @gh: the holder structure to add
1081 static void add_to_queue(struct gfs2_holder
*gh
)
1083 struct gfs2_glock
*gl
= gh
->gh_gl
;
1084 struct gfs2_holder
*existing
;
1086 BUG_ON(gh
->gh_owner_pid
== NULL
);
1087 if (test_and_set_bit(HIF_WAIT
, &gh
->gh_iflags
))
1090 if (!(gh
->gh_flags
& GL_FLOCK
)) {
1091 existing
= find_holder_by_owner(&gl
->gl_holders
,
1094 print_symbol(KERN_WARNING
"original: %s\n",
1096 printk(KERN_INFO
"pid : %d\n",
1097 pid_nr(existing
->gh_owner_pid
));
1098 printk(KERN_INFO
"lock type : %d lock state : %d\n",
1099 existing
->gh_gl
->gl_name
.ln_type
,
1100 existing
->gh_gl
->gl_state
);
1101 print_symbol(KERN_WARNING
"new: %s\n", gh
->gh_ip
);
1102 printk(KERN_INFO
"pid : %d\n",
1103 pid_nr(gh
->gh_owner_pid
));
1104 printk(KERN_INFO
"lock type : %d lock state : %d\n",
1105 gl
->gl_name
.ln_type
, gl
->gl_state
);
1109 existing
= find_holder_by_owner(&gl
->gl_waiters3
,
1112 print_symbol(KERN_WARNING
"original: %s\n",
1114 print_symbol(KERN_WARNING
"new: %s\n", gh
->gh_ip
);
1119 if (gh
->gh_flags
& LM_FLAG_PRIORITY
)
1120 list_add(&gh
->gh_list
, &gl
->gl_waiters3
);
1122 list_add_tail(&gh
->gh_list
, &gl
->gl_waiters3
);
1126 * gfs2_glock_nq - enqueue a struct gfs2_holder onto a glock (acquire a glock)
1127 * @gh: the holder structure
1129 * if (gh->gh_flags & GL_ASYNC), this never returns an error
1131 * Returns: 0, GLR_TRYFAILED, or errno on failure
1134 int gfs2_glock_nq(struct gfs2_holder
*gh
)
1136 struct gfs2_glock
*gl
= gh
->gh_gl
;
1137 struct gfs2_sbd
*sdp
= gl
->gl_sbd
;
1141 if (unlikely(test_bit(SDF_SHUTDOWN
, &sdp
->sd_flags
))) {
1142 set_bit(HIF_ABORTED
, &gh
->gh_iflags
);
1146 spin_lock(&gl
->gl_spin
);
1149 spin_unlock(&gl
->gl_spin
);
1151 if (!(gh
->gh_flags
& GL_ASYNC
)) {
1152 error
= glock_wait_internal(gh
);
1153 if (error
== GLR_CANCELED
) {
1163 * gfs2_glock_poll - poll to see if an async request has been completed
1166 * Returns: 1 if the request is ready to be gfs2_glock_wait()ed on
1169 int gfs2_glock_poll(struct gfs2_holder
*gh
)
1171 struct gfs2_glock
*gl
= gh
->gh_gl
;
1174 spin_lock(&gl
->gl_spin
);
1176 if (test_bit(HIF_HOLDER
, &gh
->gh_iflags
))
1178 else if (list_empty(&gh
->gh_list
)) {
1179 if (gh
->gh_error
== GLR_CANCELED
) {
1180 spin_unlock(&gl
->gl_spin
);
1182 if (gfs2_glock_nq(gh
))
1189 spin_unlock(&gl
->gl_spin
);
1195 * gfs2_glock_wait - wait for a lock acquisition that ended in a GLR_ASYNC
1196 * @gh: the holder structure
1198 * Returns: 0, GLR_TRYFAILED, or errno on failure
1201 int gfs2_glock_wait(struct gfs2_holder
*gh
)
1205 error
= glock_wait_internal(gh
);
1206 if (error
== GLR_CANCELED
) {
1208 gh
->gh_flags
&= ~GL_ASYNC
;
1209 error
= gfs2_glock_nq(gh
);
1216 * gfs2_glock_dq - dequeue a struct gfs2_holder from a glock (release a glock)
1217 * @gh: the glock holder
1221 void gfs2_glock_dq(struct gfs2_holder
*gh
)
1223 struct gfs2_glock
*gl
= gh
->gh_gl
;
1224 const struct gfs2_glock_operations
*glops
= gl
->gl_ops
;
1227 if (gh
->gh_flags
& GL_NOCACHE
)
1228 handle_callback(gl
, LM_ST_UNLOCKED
, 0, 0);
1230 gfs2_glmutex_lock(gl
);
1232 spin_lock(&gl
->gl_spin
);
1233 list_del_init(&gh
->gh_list
);
1235 if (list_empty(&gl
->gl_holders
)) {
1236 if (glops
->go_unlock
) {
1237 spin_unlock(&gl
->gl_spin
);
1238 glops
->go_unlock(gh
);
1239 spin_lock(&gl
->gl_spin
);
1241 gl
->gl_stamp
= jiffies
;
1244 clear_bit(GLF_LOCK
, &gl
->gl_flags
);
1245 spin_unlock(&gl
->gl_spin
);
1247 gfs2_glock_hold(gl
);
1248 if (test_bit(GLF_PENDING_DEMOTE
, &gl
->gl_flags
) &&
1249 !test_bit(GLF_DEMOTE
, &gl
->gl_flags
))
1250 delay
= gl
->gl_ops
->go_min_hold_time
;
1251 if (queue_delayed_work(glock_workqueue
, &gl
->gl_work
, delay
) == 0)
1255 void gfs2_glock_dq_wait(struct gfs2_holder
*gh
)
1257 struct gfs2_glock
*gl
= gh
->gh_gl
;
1263 * gfs2_glock_dq_uninit - dequeue a holder from a glock and initialize it
1264 * @gh: the holder structure
1268 void gfs2_glock_dq_uninit(struct gfs2_holder
*gh
)
1271 gfs2_holder_uninit(gh
);
1275 * gfs2_glock_nq_num - acquire a glock based on lock number
1276 * @sdp: the filesystem
1277 * @number: the lock number
1278 * @glops: the glock operations for the type of glock
1279 * @state: the state to acquire the glock in
1280 * @flags: modifier flags for the aquisition
1281 * @gh: the struct gfs2_holder
1286 int gfs2_glock_nq_num(struct gfs2_sbd
*sdp
, u64 number
,
1287 const struct gfs2_glock_operations
*glops
,
1288 unsigned int state
, int flags
, struct gfs2_holder
*gh
)
1290 struct gfs2_glock
*gl
;
1293 error
= gfs2_glock_get(sdp
, number
, glops
, CREATE
, &gl
);
1295 error
= gfs2_glock_nq_init(gl
, state
, flags
, gh
);
1303 * glock_compare - Compare two struct gfs2_glock structures for sorting
1304 * @arg_a: the first structure
1305 * @arg_b: the second structure
1309 static int glock_compare(const void *arg_a
, const void *arg_b
)
1311 const struct gfs2_holder
*gh_a
= *(const struct gfs2_holder
**)arg_a
;
1312 const struct gfs2_holder
*gh_b
= *(const struct gfs2_holder
**)arg_b
;
1313 const struct lm_lockname
*a
= &gh_a
->gh_gl
->gl_name
;
1314 const struct lm_lockname
*b
= &gh_b
->gh_gl
->gl_name
;
1316 if (a
->ln_number
> b
->ln_number
)
1318 if (a
->ln_number
< b
->ln_number
)
1320 BUG_ON(gh_a
->gh_gl
->gl_ops
->go_type
== gh_b
->gh_gl
->gl_ops
->go_type
);
1325 * nq_m_sync - synchonously acquire more than one glock in deadlock free order
1326 * @num_gh: the number of structures
1327 * @ghs: an array of struct gfs2_holder structures
1329 * Returns: 0 on success (all glocks acquired),
1330 * errno on failure (no glocks acquired)
1333 static int nq_m_sync(unsigned int num_gh
, struct gfs2_holder
*ghs
,
1334 struct gfs2_holder
**p
)
1339 for (x
= 0; x
< num_gh
; x
++)
1342 sort(p
, num_gh
, sizeof(struct gfs2_holder
*), glock_compare
, NULL
);
1344 for (x
= 0; x
< num_gh
; x
++) {
1345 p
[x
]->gh_flags
&= ~(LM_FLAG_TRY
| GL_ASYNC
);
1347 error
= gfs2_glock_nq(p
[x
]);
1350 gfs2_glock_dq(p
[x
]);
1359 * gfs2_glock_nq_m - acquire multiple glocks
1360 * @num_gh: the number of structures
1361 * @ghs: an array of struct gfs2_holder structures
1364 * Returns: 0 on success (all glocks acquired),
1365 * errno on failure (no glocks acquired)
1368 int gfs2_glock_nq_m(unsigned int num_gh
, struct gfs2_holder
*ghs
)
1370 struct gfs2_holder
*tmp
[4];
1371 struct gfs2_holder
**pph
= tmp
;
1378 ghs
->gh_flags
&= ~(LM_FLAG_TRY
| GL_ASYNC
);
1379 return gfs2_glock_nq(ghs
);
1383 pph
= kmalloc(num_gh
* sizeof(struct gfs2_holder
*), GFP_NOFS
);
1388 error
= nq_m_sync(num_gh
, ghs
, pph
);
1397 * gfs2_glock_dq_m - release multiple glocks
1398 * @num_gh: the number of structures
1399 * @ghs: an array of struct gfs2_holder structures
1403 void gfs2_glock_dq_m(unsigned int num_gh
, struct gfs2_holder
*ghs
)
1407 for (x
= 0; x
< num_gh
; x
++)
1408 gfs2_glock_dq(&ghs
[x
]);
1412 * gfs2_glock_dq_uninit_m - release multiple glocks
1413 * @num_gh: the number of structures
1414 * @ghs: an array of struct gfs2_holder structures
1418 void gfs2_glock_dq_uninit_m(unsigned int num_gh
, struct gfs2_holder
*ghs
)
1422 for (x
= 0; x
< num_gh
; x
++)
1423 gfs2_glock_dq_uninit(&ghs
[x
]);
1427 * gfs2_lvb_hold - attach a LVB from a glock
1428 * @gl: The glock in question
1432 int gfs2_lvb_hold(struct gfs2_glock
*gl
)
1436 gfs2_glmutex_lock(gl
);
1438 if (!atomic_read(&gl
->gl_lvb_count
)) {
1439 error
= gfs2_lm_hold_lvb(gl
->gl_sbd
, gl
->gl_lock
, &gl
->gl_lvb
);
1441 gfs2_glmutex_unlock(gl
);
1444 gfs2_glock_hold(gl
);
1446 atomic_inc(&gl
->gl_lvb_count
);
1448 gfs2_glmutex_unlock(gl
);
1454 * gfs2_lvb_unhold - detach a LVB from a glock
1455 * @gl: The glock in question
1459 void gfs2_lvb_unhold(struct gfs2_glock
*gl
)
1461 gfs2_glock_hold(gl
);
1462 gfs2_glmutex_lock(gl
);
1464 gfs2_assert(gl
->gl_sbd
, atomic_read(&gl
->gl_lvb_count
) > 0);
1465 if (atomic_dec_and_test(&gl
->gl_lvb_count
)) {
1466 gfs2_lm_unhold_lvb(gl
->gl_sbd
, gl
->gl_lock
, gl
->gl_lvb
);
1471 gfs2_glmutex_unlock(gl
);
1475 static void blocking_cb(struct gfs2_sbd
*sdp
, struct lm_lockname
*name
,
1478 struct gfs2_glock
*gl
;
1479 unsigned long delay
= 0;
1480 unsigned long holdtime
;
1481 unsigned long now
= jiffies
;
1483 gl
= gfs2_glock_find(sdp
, name
);
1487 holdtime
= gl
->gl_tchange
+ gl
->gl_ops
->go_min_hold_time
;
1488 if (time_before(now
, holdtime
))
1489 delay
= holdtime
- now
;
1491 handle_callback(gl
, state
, 1, delay
);
1492 if (queue_delayed_work(glock_workqueue
, &gl
->gl_work
, delay
) == 0)
1497 * gfs2_glock_cb - Callback used by locking module
1498 * @sdp: Pointer to the superblock
1499 * @type: Type of callback
1500 * @data: Type dependent data pointer
1502 * Called by the locking module when it wants to tell us something.
1503 * Either we need to drop a lock, one of our ASYNC requests completed, or
1504 * a journal from another client needs to be recovered.
1507 void gfs2_glock_cb(void *cb_data
, unsigned int type
, void *data
)
1509 struct gfs2_sbd
*sdp
= cb_data
;
1513 blocking_cb(sdp
, data
, LM_ST_UNLOCKED
);
1517 blocking_cb(sdp
, data
, LM_ST_DEFERRED
);
1521 blocking_cb(sdp
, data
, LM_ST_SHARED
);
1525 struct lm_async_cb
*async
= data
;
1526 struct gfs2_glock
*gl
;
1528 down_read(&gfs2_umount_flush_sem
);
1529 gl
= gfs2_glock_find(sdp
, &async
->lc_name
);
1530 if (gfs2_assert_warn(sdp
, gl
))
1532 if (!gfs2_assert_warn(sdp
, gl
->gl_req_bh
))
1533 gl
->gl_req_bh(gl
, async
->lc_ret
);
1534 if (queue_delayed_work(glock_workqueue
, &gl
->gl_work
, 0) == 0)
1536 up_read(&gfs2_umount_flush_sem
);
1540 case LM_CB_NEED_RECOVERY
:
1541 gfs2_jdesc_make_dirty(sdp
, *(unsigned int *)data
);
1542 if (sdp
->sd_recoverd_process
)
1543 wake_up_process(sdp
->sd_recoverd_process
);
1546 case LM_CB_DROPLOCKS
:
1547 gfs2_gl_hash_clear(sdp
, NO_WAIT
);
1548 gfs2_quota_scan(sdp
);
1552 gfs2_assert_warn(sdp
, 0);
1558 * demote_ok - Check to see if it's ok to unlock a glock
1561 * Returns: 1 if it's ok
1564 static int demote_ok(struct gfs2_glock
*gl
)
1566 const struct gfs2_glock_operations
*glops
= gl
->gl_ops
;
1569 if (test_bit(GLF_STICKY
, &gl
->gl_flags
))
1571 else if (glops
->go_demote_ok
)
1572 demote
= glops
->go_demote_ok(gl
);
1578 * gfs2_glock_schedule_for_reclaim - Add a glock to the reclaim list
1583 void gfs2_glock_schedule_for_reclaim(struct gfs2_glock
*gl
)
1585 struct gfs2_sbd
*sdp
= gl
->gl_sbd
;
1587 spin_lock(&sdp
->sd_reclaim_lock
);
1588 if (list_empty(&gl
->gl_reclaim
)) {
1589 gfs2_glock_hold(gl
);
1590 list_add(&gl
->gl_reclaim
, &sdp
->sd_reclaim_list
);
1591 atomic_inc(&sdp
->sd_reclaim_count
);
1593 spin_unlock(&sdp
->sd_reclaim_lock
);
1595 wake_up(&sdp
->sd_reclaim_wq
);
1599 * gfs2_reclaim_glock - process the next glock on the filesystem's reclaim list
1600 * @sdp: the filesystem
1602 * Called from gfs2_glockd() glock reclaim daemon, or when promoting a
1603 * different glock and we notice that there are a lot of glocks in the
1608 void gfs2_reclaim_glock(struct gfs2_sbd
*sdp
)
1610 struct gfs2_glock
*gl
;
1612 spin_lock(&sdp
->sd_reclaim_lock
);
1613 if (list_empty(&sdp
->sd_reclaim_list
)) {
1614 spin_unlock(&sdp
->sd_reclaim_lock
);
1617 gl
= list_entry(sdp
->sd_reclaim_list
.next
,
1618 struct gfs2_glock
, gl_reclaim
);
1619 list_del_init(&gl
->gl_reclaim
);
1620 spin_unlock(&sdp
->sd_reclaim_lock
);
1622 atomic_dec(&sdp
->sd_reclaim_count
);
1623 atomic_inc(&sdp
->sd_reclaimed
);
1625 if (gfs2_glmutex_trylock(gl
)) {
1626 if (list_empty(&gl
->gl_holders
) &&
1627 gl
->gl_state
!= LM_ST_UNLOCKED
&& demote_ok(gl
))
1628 handle_callback(gl
, LM_ST_UNLOCKED
, 0, 0);
1629 gfs2_glmutex_unlock(gl
);
1636 * examine_bucket - Call a function for glock in a hash bucket
1637 * @examiner: the function
1638 * @sdp: the filesystem
1639 * @bucket: the bucket
1641 * Returns: 1 if the bucket has entries
1644 static int examine_bucket(glock_examiner examiner
, struct gfs2_sbd
*sdp
,
1647 struct gfs2_glock
*gl
, *prev
= NULL
;
1648 int has_entries
= 0;
1649 struct hlist_head
*head
= &gl_hash_table
[hash
].hb_list
;
1651 read_lock(gl_lock_addr(hash
));
1652 /* Can't use hlist_for_each_entry - don't want prefetch here */
1653 if (hlist_empty(head
))
1655 gl
= list_entry(head
->first
, struct gfs2_glock
, gl_list
);
1657 if (!sdp
|| gl
->gl_sbd
== sdp
) {
1658 gfs2_glock_hold(gl
);
1659 read_unlock(gl_lock_addr(hash
));
1661 gfs2_glock_put(prev
);
1665 read_lock(gl_lock_addr(hash
));
1667 if (gl
->gl_list
.next
== NULL
)
1669 gl
= list_entry(gl
->gl_list
.next
, struct gfs2_glock
, gl_list
);
1672 read_unlock(gl_lock_addr(hash
));
1674 gfs2_glock_put(prev
);
1680 * scan_glock - look at a glock and see if we can reclaim it
1681 * @gl: the glock to look at
1685 static void scan_glock(struct gfs2_glock
*gl
)
1687 if (gl
->gl_ops
== &gfs2_inode_glops
&& gl
->gl_object
)
1690 if (gfs2_glmutex_trylock(gl
)) {
1691 if (list_empty(&gl
->gl_holders
) &&
1692 gl
->gl_state
!= LM_ST_UNLOCKED
&& demote_ok(gl
))
1694 gfs2_glmutex_unlock(gl
);
1699 gfs2_glmutex_unlock(gl
);
1700 gfs2_glock_schedule_for_reclaim(gl
);
1704 * clear_glock - look at a glock and see if we can free it from glock cache
1705 * @gl: the glock to look at
1709 static void clear_glock(struct gfs2_glock
*gl
)
1711 struct gfs2_sbd
*sdp
= gl
->gl_sbd
;
1714 spin_lock(&sdp
->sd_reclaim_lock
);
1715 if (!list_empty(&gl
->gl_reclaim
)) {
1716 list_del_init(&gl
->gl_reclaim
);
1717 atomic_dec(&sdp
->sd_reclaim_count
);
1718 spin_unlock(&sdp
->sd_reclaim_lock
);
1719 released
= gfs2_glock_put(gl
);
1720 gfs2_assert(sdp
, !released
);
1722 spin_unlock(&sdp
->sd_reclaim_lock
);
1725 if (gfs2_glmutex_trylock(gl
)) {
1726 if (list_empty(&gl
->gl_holders
) &&
1727 gl
->gl_state
!= LM_ST_UNLOCKED
)
1728 handle_callback(gl
, LM_ST_UNLOCKED
, 0, 0);
1729 gfs2_glmutex_unlock(gl
);
1734 * gfs2_gl_hash_clear - Empty out the glock hash table
1735 * @sdp: the filesystem
1736 * @wait: wait until it's all gone
1738 * Called when unmounting the filesystem, or when inter-node lock manager
1739 * requests DROPLOCKS because it is running out of capacity.
1742 void gfs2_gl_hash_clear(struct gfs2_sbd
*sdp
, int wait
)
1752 for (x
= 0; x
< GFS2_GL_HASH_SIZE
; x
++) {
1753 if (examine_bucket(clear_glock
, sdp
, x
))
1760 if (time_after_eq(jiffies
,
1761 t
+ gfs2_tune_get(sdp
, gt_stall_secs
) * HZ
)) {
1762 fs_warn(sdp
, "Unmount seems to be stalled. "
1763 "Dumping lock state...\n");
1764 gfs2_dump_lockstate(sdp
);
1768 down_write(&gfs2_umount_flush_sem
);
1769 invalidate_inodes(sdp
->sd_vfs
);
1770 up_write(&gfs2_umount_flush_sem
);
1776 * Diagnostic routines to help debug distributed deadlock
1779 static void gfs2_print_symbol(struct glock_iter
*gi
, const char *fmt
,
1780 unsigned long address
)
1782 char buffer
[KSYM_SYMBOL_LEN
];
1784 sprint_symbol(buffer
, address
);
1785 print_dbg(gi
, fmt
, buffer
);
1789 * dump_holder - print information about a glock holder
1790 * @str: a string naming the type of holder
1791 * @gh: the glock holder
1793 * Returns: 0 on success, -ENOBUFS when we run out of space
1796 static int dump_holder(struct glock_iter
*gi
, char *str
,
1797 struct gfs2_holder
*gh
)
1800 struct task_struct
*gh_owner
;
1802 print_dbg(gi
, " %s\n", str
);
1803 if (gh
->gh_owner_pid
) {
1804 print_dbg(gi
, " owner = %ld ",
1805 (long)pid_nr(gh
->gh_owner_pid
));
1806 gh_owner
= pid_task(gh
->gh_owner_pid
, PIDTYPE_PID
);
1808 print_dbg(gi
, "(%s)\n", gh_owner
->comm
);
1810 print_dbg(gi
, "(ended)\n");
1812 print_dbg(gi
, " owner = -1\n");
1813 print_dbg(gi
, " gh_state = %u\n", gh
->gh_state
);
1814 print_dbg(gi
, " gh_flags =");
1815 for (x
= 0; x
< 32; x
++)
1816 if (gh
->gh_flags
& (1 << x
))
1817 print_dbg(gi
, " %u", x
);
1818 print_dbg(gi
, " \n");
1819 print_dbg(gi
, " error = %d\n", gh
->gh_error
);
1820 print_dbg(gi
, " gh_iflags =");
1821 for (x
= 0; x
< 32; x
++)
1822 if (test_bit(x
, &gh
->gh_iflags
))
1823 print_dbg(gi
, " %u", x
);
1824 print_dbg(gi
, " \n");
1825 gfs2_print_symbol(gi
, " initialized at: %s\n", gh
->gh_ip
);
1831 * dump_inode - print information about an inode
1834 * Returns: 0 on success, -ENOBUFS when we run out of space
1837 static int dump_inode(struct glock_iter
*gi
, struct gfs2_inode
*ip
)
1841 print_dbg(gi
, " Inode:\n");
1842 print_dbg(gi
, " num = %llu/%llu\n",
1843 (unsigned long long)ip
->i_no_formal_ino
,
1844 (unsigned long long)ip
->i_no_addr
);
1845 print_dbg(gi
, " type = %u\n", IF2DT(ip
->i_inode
.i_mode
));
1846 print_dbg(gi
, " i_flags =");
1847 for (x
= 0; x
< 32; x
++)
1848 if (test_bit(x
, &ip
->i_flags
))
1849 print_dbg(gi
, " %u", x
);
1850 print_dbg(gi
, " \n");
1855 * dump_glock - print information about a glock
1857 * @count: where we are in the buffer
1859 * Returns: 0 on success, -ENOBUFS when we run out of space
1862 static int dump_glock(struct glock_iter
*gi
, struct gfs2_glock
*gl
)
1864 struct gfs2_holder
*gh
;
1866 int error
= -ENOBUFS
;
1867 struct task_struct
*gl_owner
;
1869 spin_lock(&gl
->gl_spin
);
1871 print_dbg(gi
, "Glock 0x%p (%u, 0x%llx)\n", gl
, gl
->gl_name
.ln_type
,
1872 (unsigned long long)gl
->gl_name
.ln_number
);
1873 print_dbg(gi
, " gl_flags =");
1874 for (x
= 0; x
< 32; x
++) {
1875 if (test_bit(x
, &gl
->gl_flags
))
1876 print_dbg(gi
, " %u", x
);
1878 if (!test_bit(GLF_LOCK
, &gl
->gl_flags
))
1879 print_dbg(gi
, " (unlocked)");
1880 print_dbg(gi
, " \n");
1881 print_dbg(gi
, " gl_ref = %d\n", atomic_read(&gl
->gl_ref
));
1882 print_dbg(gi
, " gl_state = %u\n", gl
->gl_state
);
1883 if (gl
->gl_owner_pid
) {
1884 gl_owner
= find_task_by_pid(gl
->gl_owner_pid
);
1886 print_dbg(gi
, " gl_owner = pid %d (%s)\n",
1887 gl
->gl_owner_pid
, gl_owner
->comm
);
1889 print_dbg(gi
, " gl_owner = %d (ended)\n",
1892 print_dbg(gi
, " gl_owner = -1\n");
1893 print_dbg(gi
, " gl_ip = %lu\n", gl
->gl_ip
);
1894 print_dbg(gi
, " req_gh = %s\n", (gl
->gl_req_gh
) ? "yes" : "no");
1895 print_dbg(gi
, " req_bh = %s\n", (gl
->gl_req_bh
) ? "yes" : "no");
1896 print_dbg(gi
, " lvb_count = %d\n", atomic_read(&gl
->gl_lvb_count
));
1897 print_dbg(gi
, " object = %s\n", (gl
->gl_object
) ? "yes" : "no");
1898 print_dbg(gi
, " reclaim = %s\n",
1899 (list_empty(&gl
->gl_reclaim
)) ? "no" : "yes");
1901 print_dbg(gi
, " aspace = 0x%p nrpages = %lu\n", gl
->gl_aspace
,
1902 gl
->gl_aspace
->i_mapping
->nrpages
);
1904 print_dbg(gi
, " aspace = no\n");
1905 print_dbg(gi
, " ail = %d\n", atomic_read(&gl
->gl_ail_count
));
1906 if (gl
->gl_req_gh
) {
1907 error
= dump_holder(gi
, "Request", gl
->gl_req_gh
);
1911 list_for_each_entry(gh
, &gl
->gl_holders
, gh_list
) {
1912 error
= dump_holder(gi
, "Holder", gh
);
1916 list_for_each_entry(gh
, &gl
->gl_waiters1
, gh_list
) {
1917 error
= dump_holder(gi
, "Waiter1", gh
);
1921 list_for_each_entry(gh
, &gl
->gl_waiters3
, gh_list
) {
1922 error
= dump_holder(gi
, "Waiter3", gh
);
1926 if (test_bit(GLF_DEMOTE
, &gl
->gl_flags
)) {
1927 print_dbg(gi
, " Demotion req to state %u (%llu uS ago)\n",
1928 gl
->gl_demote_state
, (unsigned long long)
1929 (jiffies
- gl
->gl_demote_time
)*(1000000/HZ
));
1931 if (gl
->gl_ops
== &gfs2_inode_glops
&& gl
->gl_object
) {
1932 if (!test_bit(GLF_LOCK
, &gl
->gl_flags
) &&
1933 list_empty(&gl
->gl_holders
)) {
1934 error
= dump_inode(gi
, gl
->gl_object
);
1939 print_dbg(gi
, " Inode: busy\n");
1946 spin_unlock(&gl
->gl_spin
);
1951 * gfs2_dump_lockstate - print out the current lockstate
1952 * @sdp: the filesystem
1953 * @ub: the buffer to copy the information into
1955 * If @ub is NULL, dump the lockstate to the console.
1959 static int gfs2_dump_lockstate(struct gfs2_sbd
*sdp
)
1961 struct gfs2_glock
*gl
;
1962 struct hlist_node
*h
;
1966 for (x
= 0; x
< GFS2_GL_HASH_SIZE
; x
++) {
1968 read_lock(gl_lock_addr(x
));
1970 hlist_for_each_entry(gl
, h
, &gl_hash_table
[x
].hb_list
, gl_list
) {
1971 if (gl
->gl_sbd
!= sdp
)
1974 error
= dump_glock(NULL
, gl
);
1979 read_unlock(gl_lock_addr(x
));
1990 * gfs2_scand - Look for cached glocks and inodes to toss from memory
1991 * @sdp: Pointer to GFS2 superblock
1993 * One of these daemons runs, finding candidates to add to sd_reclaim_list.
1997 static int gfs2_scand(void *data
)
2002 while (!kthread_should_stop()) {
2003 for (x
= 0; x
< GFS2_GL_HASH_SIZE
; x
++)
2004 examine_bucket(scan_glock
, NULL
, x
);
2005 if (freezing(current
))
2010 schedule_timeout_interruptible(delay
* HZ
);
2018 int __init
gfs2_glock_init(void)
2021 for(i
= 0; i
< GFS2_GL_HASH_SIZE
; i
++) {
2022 INIT_HLIST_HEAD(&gl_hash_table
[i
].hb_list
);
2024 #ifdef GL_HASH_LOCK_SZ
2025 for(i
= 0; i
< GL_HASH_LOCK_SZ
; i
++) {
2026 rwlock_init(&gl_hash_locks
[i
]);
2030 scand_process
= kthread_run(gfs2_scand
, NULL
, "gfs2_scand");
2031 if (IS_ERR(scand_process
))
2032 return PTR_ERR(scand_process
);
2034 glock_workqueue
= create_workqueue("glock_workqueue");
2035 if (IS_ERR(glock_workqueue
)) {
2036 kthread_stop(scand_process
);
2037 return PTR_ERR(glock_workqueue
);
2043 void gfs2_glock_exit(void)
2045 destroy_workqueue(glock_workqueue
);
2046 kthread_stop(scand_process
);
2049 module_param(scand_secs
, uint
, S_IRUGO
|S_IWUSR
);
2050 MODULE_PARM_DESC(scand_secs
, "The number of seconds between scand runs");
2052 static int gfs2_glock_iter_next(struct glock_iter
*gi
)
2054 struct gfs2_glock
*gl
;
2057 read_lock(gl_lock_addr(gi
->hash
));
2060 gi
->gl
= hlist_entry(gl
->gl_list
.next
,
2061 struct gfs2_glock
, gl_list
);
2063 gfs2_glock_hold(gi
->gl
);
2065 read_unlock(gl_lock_addr(gi
->hash
));
2068 if (gl
&& gi
->gl
== NULL
)
2070 while(gi
->gl
== NULL
) {
2071 if (gi
->hash
>= GFS2_GL_HASH_SIZE
)
2073 read_lock(gl_lock_addr(gi
->hash
));
2074 gi
->gl
= hlist_entry(gl_hash_table
[gi
->hash
].hb_list
.first
,
2075 struct gfs2_glock
, gl_list
);
2077 gfs2_glock_hold(gi
->gl
);
2078 read_unlock(gl_lock_addr(gi
->hash
));
2082 if (gi
->sdp
!= gi
->gl
->gl_sbd
)
2088 static void gfs2_glock_iter_free(struct glock_iter
*gi
)
2091 gfs2_glock_put(gi
->gl
);
2095 static struct glock_iter
*gfs2_glock_iter_init(struct gfs2_sbd
*sdp
)
2097 struct glock_iter
*gi
;
2099 gi
= kmalloc(sizeof (*gi
), GFP_KERNEL
);
2107 memset(gi
->string
, 0, sizeof(gi
->string
));
2109 if (gfs2_glock_iter_next(gi
)) {
2110 gfs2_glock_iter_free(gi
);
2117 static void *gfs2_glock_seq_start(struct seq_file
*file
, loff_t
*pos
)
2119 struct glock_iter
*gi
;
2122 gi
= gfs2_glock_iter_init(file
->private);
2127 if (gfs2_glock_iter_next(gi
)) {
2128 gfs2_glock_iter_free(gi
);
2136 static void *gfs2_glock_seq_next(struct seq_file
*file
, void *iter_ptr
,
2139 struct glock_iter
*gi
= iter_ptr
;
2143 if (gfs2_glock_iter_next(gi
)) {
2144 gfs2_glock_iter_free(gi
);
2151 static void gfs2_glock_seq_stop(struct seq_file
*file
, void *iter_ptr
)
2153 struct glock_iter
*gi
= iter_ptr
;
2155 gfs2_glock_iter_free(gi
);
2158 static int gfs2_glock_seq_show(struct seq_file
*file
, void *iter_ptr
)
2160 struct glock_iter
*gi
= iter_ptr
;
2163 dump_glock(gi
, gi
->gl
);
2168 static const struct seq_operations gfs2_glock_seq_ops
= {
2169 .start
= gfs2_glock_seq_start
,
2170 .next
= gfs2_glock_seq_next
,
2171 .stop
= gfs2_glock_seq_stop
,
2172 .show
= gfs2_glock_seq_show
,
2175 static int gfs2_debugfs_open(struct inode
*inode
, struct file
*file
)
2177 struct seq_file
*seq
;
2180 ret
= seq_open(file
, &gfs2_glock_seq_ops
);
2184 seq
= file
->private_data
;
2185 seq
->private = inode
->i_private
;
2190 static const struct file_operations gfs2_debug_fops
= {
2191 .owner
= THIS_MODULE
,
2192 .open
= gfs2_debugfs_open
,
2194 .llseek
= seq_lseek
,
2195 .release
= seq_release
2198 int gfs2_create_debugfs_file(struct gfs2_sbd
*sdp
)
2200 sdp
->debugfs_dir
= debugfs_create_dir(sdp
->sd_table_name
, gfs2_root
);
2201 if (!sdp
->debugfs_dir
)
2203 sdp
->debugfs_dentry_glocks
= debugfs_create_file("glocks",
2205 sdp
->debugfs_dir
, sdp
,
2207 if (!sdp
->debugfs_dentry_glocks
)
2213 void gfs2_delete_debugfs_file(struct gfs2_sbd
*sdp
)
2215 if (sdp
&& sdp
->debugfs_dir
) {
2216 if (sdp
->debugfs_dentry_glocks
) {
2217 debugfs_remove(sdp
->debugfs_dentry_glocks
);
2218 sdp
->debugfs_dentry_glocks
= NULL
;
2220 debugfs_remove(sdp
->debugfs_dir
);
2221 sdp
->debugfs_dir
= NULL
;
2225 int gfs2_register_debugfs(void)
2227 gfs2_root
= debugfs_create_dir("gfs2", NULL
);
2228 return gfs2_root
? 0 : -ENOMEM
;
2231 void gfs2_unregister_debugfs(void)
2233 debugfs_remove(gfs2_root
);