4 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
6 * This program is free software; you can redistribute it and/or modify
7 * it under the terms of the GNU General Public License version 2 only,
8 * as published by the Free Software Foundation.
10 * This program is distributed in the hope that it will be useful, but
11 * WITHOUT ANY WARRANTY; without even the implied warranty of
12 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
13 * General Public License version 2 for more details (a copy is included
14 * in the LICENSE file that accompanied this code).
16 * You should have received a copy of the GNU General Public License
17 * version 2 along with this program; If not, see
18 * http://www.sun.com/software/products/lustre/docs/GPLv2.pdf
20 * Please contact Sun Microsystems, Inc., 4150 Network Circle, Santa Clara,
21 * CA 95054 USA or visit www.sun.com if you need additional information or
27 * Copyright (c) 2008, 2010, Oracle and/or its affiliates. All rights reserved.
28 * Use is subject to license terms.
30 * Copyright (c) 2011, 2013, Intel Corporation.
33 * This file is part of Lustre, http://www.lustre.org/
34 * Lustre is a trademark of Sun Microsystems, Inc.
38 * Author: Nikita Danilov <nikita.danilov@sun.com>
39 * Author: Jinshan Xiong <jinshan.xiong@intel.com>
42 #define DEBUG_SUBSYSTEM S_CLASS
44 #include <libcfs/libcfs.h>
45 #include <obd_class.h>
46 #include <obd_support.h>
47 #include <lustre_fid.h>
48 #include <libcfs/list.h>
49 #include <cl_object.h>
50 #include "cl_internal.h"
52 /** Lock class of cl_lock::cll_guard */
53 static struct lock_class_key cl_lock_guard_class;
54 static struct kmem_cache *cl_lock_kmem;
56 static struct lu_kmem_descr cl_lock_caches[] = {
58 .ckd_cache = &cl_lock_kmem,
59 .ckd_name = "cl_lock_kmem",
60 .ckd_size = sizeof (struct cl_lock)
67 #ifdef CONFIG_DEBUG_PAGESTATE_TRACKING
68 #define CS_LOCK_INC(o, item) \
69 atomic_inc(&cl_object_site(o)->cs_locks.cs_stats[CS_##item])
70 #define CS_LOCK_DEC(o, item) \
71 atomic_dec(&cl_object_site(o)->cs_locks.cs_stats[CS_##item])
72 #define CS_LOCKSTATE_INC(o, state) \
73 atomic_inc(&cl_object_site(o)->cs_locks_state[state])
74 #define CS_LOCKSTATE_DEC(o, state) \
75 atomic_dec(&cl_object_site(o)->cs_locks_state[state])
77 #define CS_LOCK_INC(o, item)
78 #define CS_LOCK_DEC(o, item)
79 #define CS_LOCKSTATE_INC(o, state)
80 #define CS_LOCKSTATE_DEC(o, state)
84 * Basic lock invariant that is maintained at all times. Caller either has a
85 * reference to \a lock, or somehow assures that \a lock cannot be freed.
87 * \see cl_lock_invariant()
89 static int cl_lock_invariant_trusted(const struct lu_env *env,
90 const struct cl_lock *lock)
92 return ergo(lock->cll_state == CLS_FREEING, lock->cll_holds == 0) &&
93 atomic_read(&lock->cll_ref) >= lock->cll_holds &&
94 lock->cll_holds >= lock->cll_users &&
95 lock->cll_holds >= 0 &&
96 lock->cll_users >= 0 &&
101 * Stronger lock invariant, checking that caller has a reference on a lock.
103 * \see cl_lock_invariant_trusted()
105 static int cl_lock_invariant(const struct lu_env *env,
106 const struct cl_lock *lock)
110 result = atomic_read(&lock->cll_ref) > 0 &&
111 cl_lock_invariant_trusted(env, lock);
112 if (!result && env != NULL)
113 CL_LOCK_DEBUG(D_ERROR, env, lock, "invariant broken");
118 * Returns lock "nesting": 0 for a top-lock and 1 for a sub-lock.
120 static enum clt_nesting_level cl_lock_nesting(const struct cl_lock *lock)
122 return cl_object_header(lock->cll_descr.cld_obj)->coh_nesting;
126 * Returns a set of counters for this lock, depending on a lock nesting.
128 static struct cl_thread_counters *cl_lock_counters(const struct lu_env *env,
129 const struct cl_lock *lock)
131 struct cl_thread_info *info;
132 enum clt_nesting_level nesting;
134 info = cl_env_info(env);
135 nesting = cl_lock_nesting(lock);
136 LASSERT(nesting < ARRAY_SIZE(info->clt_counters));
137 return &info->clt_counters[nesting];
140 static void cl_lock_trace0(int level, const struct lu_env *env,
141 const char *prefix, const struct cl_lock *lock,
142 const char *func, const int line)
144 struct cl_object_header *h = cl_object_header(lock->cll_descr.cld_obj);
145 CDEBUG(level, "%s: %p@(%d %p %d %d %d %d %d %lx)"
146 "(%p/%d/%d) at %s():%d\n",
147 prefix, lock, atomic_read(&lock->cll_ref),
148 lock->cll_guarder, lock->cll_depth,
149 lock->cll_state, lock->cll_error, lock->cll_holds,
150 lock->cll_users, lock->cll_flags,
151 env, h->coh_nesting, cl_lock_nr_mutexed(env),
154 #define cl_lock_trace(level, env, prefix, lock) \
155 cl_lock_trace0(level, env, prefix, lock, __FUNCTION__, __LINE__)
157 #define RETIP ((unsigned long)__builtin_return_address(0))
159 #ifdef CONFIG_LOCKDEP
160 static struct lock_class_key cl_lock_key;
162 static void cl_lock_lockdep_init(struct cl_lock *lock)
164 lockdep_set_class_and_name(lock, &cl_lock_key, "EXT");
167 static void cl_lock_lockdep_acquire(const struct lu_env *env,
168 struct cl_lock *lock, __u32 enqflags)
170 cl_lock_counters(env, lock)->ctc_nr_locks_acquired++;
171 lock_map_acquire(&lock->dep_map);
174 static void cl_lock_lockdep_release(const struct lu_env *env,
175 struct cl_lock *lock)
177 cl_lock_counters(env, lock)->ctc_nr_locks_acquired--;
178 lock_map_release(&lock->dep_map);
181 #else /* !CONFIG_LOCKDEP */
183 static void cl_lock_lockdep_init(struct cl_lock *lock)
185 static void cl_lock_lockdep_acquire(const struct lu_env *env,
186 struct cl_lock *lock, __u32 enqflags)
188 static void cl_lock_lockdep_release(const struct lu_env *env,
189 struct cl_lock *lock)
192 #endif /* !CONFIG_LOCKDEP */
195 * Adds lock slice to the compound lock.
197 * This is called by cl_object_operations::coo_lock_init() methods to add a
198 * per-layer state to the lock. New state is added at the end of
199 * cl_lock::cll_layers list, that is, it is at the bottom of the stack.
201 * \see cl_req_slice_add(), cl_page_slice_add(), cl_io_slice_add()
203 void cl_lock_slice_add(struct cl_lock *lock, struct cl_lock_slice *slice,
204 struct cl_object *obj,
205 const struct cl_lock_operations *ops)
208 slice->cls_lock = lock;
209 cfs_list_add_tail(&slice->cls_linkage, &lock->cll_layers);
210 slice->cls_obj = obj;
211 slice->cls_ops = ops;
214 EXPORT_SYMBOL(cl_lock_slice_add);
217 * Returns true iff a lock with the mode \a has provides at least the same
218 * guarantees as a lock with the mode \a need.
220 int cl_lock_mode_match(enum cl_lock_mode has, enum cl_lock_mode need)
222 LINVRNT(need == CLM_READ || need == CLM_WRITE ||
223 need == CLM_PHANTOM || need == CLM_GROUP);
224 LINVRNT(has == CLM_READ || has == CLM_WRITE ||
225 has == CLM_PHANTOM || has == CLM_GROUP);
226 CLASSERT(CLM_PHANTOM < CLM_READ);
227 CLASSERT(CLM_READ < CLM_WRITE);
228 CLASSERT(CLM_WRITE < CLM_GROUP);
230 if (has != CLM_GROUP)
235 EXPORT_SYMBOL(cl_lock_mode_match);
238 * Returns true iff extent portions of lock descriptions match.
240 int cl_lock_ext_match(const struct cl_lock_descr *has,
241 const struct cl_lock_descr *need)
244 has->cld_start <= need->cld_start &&
245 has->cld_end >= need->cld_end &&
246 cl_lock_mode_match(has->cld_mode, need->cld_mode) &&
247 (has->cld_mode != CLM_GROUP || has->cld_gid == need->cld_gid);
249 EXPORT_SYMBOL(cl_lock_ext_match);
252 * Returns true iff a lock with the description \a has provides at least the
253 * same guarantees as a lock with the description \a need.
255 int cl_lock_descr_match(const struct cl_lock_descr *has,
256 const struct cl_lock_descr *need)
259 cl_object_same(has->cld_obj, need->cld_obj) &&
260 cl_lock_ext_match(has, need);
262 EXPORT_SYMBOL(cl_lock_descr_match);
264 static void cl_lock_free(const struct lu_env *env, struct cl_lock *lock)
266 struct cl_object *obj = lock->cll_descr.cld_obj;
268 LINVRNT(!cl_lock_is_mutexed(lock));
271 cl_lock_trace(D_DLMTRACE, env, "free lock", lock);
272 while (!cfs_list_empty(&lock->cll_layers)) {
273 struct cl_lock_slice *slice;
275 slice = cfs_list_entry(lock->cll_layers.next,
276 struct cl_lock_slice, cls_linkage);
277 cfs_list_del_init(lock->cll_layers.next);
278 slice->cls_ops->clo_fini(env, slice);
280 CS_LOCK_DEC(obj, total);
281 CS_LOCKSTATE_DEC(obj, lock->cll_state);
282 lu_object_ref_del_at(&obj->co_lu, &lock->cll_obj_ref, "cl_lock", lock);
283 cl_object_put(env, obj);
284 lu_ref_fini(&lock->cll_reference);
285 lu_ref_fini(&lock->cll_holders);
286 mutex_destroy(&lock->cll_guard);
287 OBD_SLAB_FREE_PTR(lock, cl_lock_kmem);
292 * Releases a reference on a lock.
294 * When last reference is released, lock is returned to the cache, unless it
295 * is in cl_lock_state::CLS_FREEING state, in which case it is destroyed
298 * \see cl_object_put(), cl_page_put()
300 void cl_lock_put(const struct lu_env *env, struct cl_lock *lock)
302 struct cl_object *obj;
304 LINVRNT(cl_lock_invariant(env, lock));
306 obj = lock->cll_descr.cld_obj;
307 LINVRNT(obj != NULL);
309 CDEBUG(D_TRACE, "releasing reference: %d %p %lu\n",
310 atomic_read(&lock->cll_ref), lock, RETIP);
312 if (atomic_dec_and_test(&lock->cll_ref)) {
313 if (lock->cll_state == CLS_FREEING) {
314 LASSERT(cfs_list_empty(&lock->cll_linkage));
315 cl_lock_free(env, lock);
317 CS_LOCK_DEC(obj, busy);
321 EXPORT_SYMBOL(cl_lock_put);
324 * Acquires an additional reference to a lock.
326 * This can be called only by caller already possessing a reference to \a
329 * \see cl_object_get(), cl_page_get()
331 void cl_lock_get(struct cl_lock *lock)
333 LINVRNT(cl_lock_invariant(NULL, lock));
334 CDEBUG(D_TRACE, "acquiring reference: %d %p %lu\n",
335 atomic_read(&lock->cll_ref), lock, RETIP);
336 atomic_inc(&lock->cll_ref);
338 EXPORT_SYMBOL(cl_lock_get);
341 * Acquires a reference to a lock.
343 * This is much like cl_lock_get(), except that this function can be used to
344 * acquire initial reference to the cached lock. Caller has to deal with all
345 * possible races. Use with care!
347 * \see cl_page_get_trust()
349 void cl_lock_get_trust(struct cl_lock *lock)
351 CDEBUG(D_TRACE, "acquiring trusted reference: %d %p %lu\n",
352 atomic_read(&lock->cll_ref), lock, RETIP);
353 if (atomic_inc_return(&lock->cll_ref) == 1)
354 CS_LOCK_INC(lock->cll_descr.cld_obj, busy);
356 EXPORT_SYMBOL(cl_lock_get_trust);
359 * Helper function destroying the lock that wasn't completely initialized.
361 * Other threads can acquire references to the top-lock through its
362 * sub-locks. Hence, it cannot be cl_lock_free()-ed immediately.
364 static void cl_lock_finish(const struct lu_env *env, struct cl_lock *lock)
366 cl_lock_mutex_get(env, lock);
367 cl_lock_cancel(env, lock);
368 cl_lock_delete(env, lock);
369 cl_lock_mutex_put(env, lock);
370 cl_lock_put(env, lock);
373 static struct cl_lock *cl_lock_alloc(const struct lu_env *env,
374 struct cl_object *obj,
375 const struct cl_io *io,
376 const struct cl_lock_descr *descr)
378 struct cl_lock *lock;
379 struct lu_object_header *head;
382 OBD_SLAB_ALLOC_PTR_GFP(lock, cl_lock_kmem, GFP_NOFS);
384 atomic_set(&lock->cll_ref, 1);
385 lock->cll_descr = *descr;
386 lock->cll_state = CLS_NEW;
388 lu_object_ref_add_at(&obj->co_lu, &lock->cll_obj_ref, "cl_lock",
390 CFS_INIT_LIST_HEAD(&lock->cll_layers);
391 CFS_INIT_LIST_HEAD(&lock->cll_linkage);
392 CFS_INIT_LIST_HEAD(&lock->cll_inclosure);
393 lu_ref_init(&lock->cll_reference);
394 lu_ref_init(&lock->cll_holders);
395 mutex_init(&lock->cll_guard);
396 lockdep_set_class(&lock->cll_guard, &cl_lock_guard_class);
397 init_waitqueue_head(&lock->cll_wq);
398 head = obj->co_lu.lo_header;
399 CS_LOCKSTATE_INC(obj, CLS_NEW);
400 CS_LOCK_INC(obj, total);
401 CS_LOCK_INC(obj, create);
402 cl_lock_lockdep_init(lock);
403 cfs_list_for_each_entry(obj, &head->loh_layers,
407 err = obj->co_ops->coo_lock_init(env, obj, lock, io);
409 cl_lock_finish(env, lock);
415 lock = ERR_PTR(-ENOMEM);
420 * Transfer the lock into INTRANSIT state and return the original state.
422 * \pre state: CLS_CACHED, CLS_HELD or CLS_ENQUEUED
423 * \post state: CLS_INTRANSIT
426 enum cl_lock_state cl_lock_intransit(const struct lu_env *env,
427 struct cl_lock *lock)
429 enum cl_lock_state state = lock->cll_state;
431 LASSERT(cl_lock_is_mutexed(lock));
432 LASSERT(state != CLS_INTRANSIT);
433 LASSERTF(state >= CLS_ENQUEUED && state <= CLS_CACHED,
434 "Malformed lock state %d.\n", state);
436 cl_lock_state_set(env, lock, CLS_INTRANSIT);
437 lock->cll_intransit_owner = current;
438 cl_lock_hold_add(env, lock, "intransit", current);
441 EXPORT_SYMBOL(cl_lock_intransit);
444 * Exit the intransit state and restore the lock state to the original state
446 void cl_lock_extransit(const struct lu_env *env, struct cl_lock *lock,
447 enum cl_lock_state state)
449 LASSERT(cl_lock_is_mutexed(lock));
450 LASSERT(lock->cll_state == CLS_INTRANSIT);
451 LASSERT(state != CLS_INTRANSIT);
452 LASSERT(lock->cll_intransit_owner == current);
454 lock->cll_intransit_owner = NULL;
455 cl_lock_state_set(env, lock, state);
456 cl_lock_unhold(env, lock, "intransit", current);
458 EXPORT_SYMBOL(cl_lock_extransit);
461 * Checking whether the lock is intransit state
463 int cl_lock_is_intransit(struct cl_lock *lock)
465 LASSERT(cl_lock_is_mutexed(lock));
466 return lock->cll_state == CLS_INTRANSIT &&
467 lock->cll_intransit_owner != current;
469 EXPORT_SYMBOL(cl_lock_is_intransit);
471 * Returns true iff lock is "suitable" for given io. E.g., locks acquired by
472 * truncate and O_APPEND cannot be reused for read/non-append-write, as they
473 * cover multiple stripes and can trigger cascading timeouts.
475 static int cl_lock_fits_into(const struct lu_env *env,
476 const struct cl_lock *lock,
477 const struct cl_lock_descr *need,
478 const struct cl_io *io)
480 const struct cl_lock_slice *slice;
482 LINVRNT(cl_lock_invariant_trusted(env, lock));
484 cfs_list_for_each_entry(slice, &lock->cll_layers, cls_linkage) {
485 if (slice->cls_ops->clo_fits_into != NULL &&
486 !slice->cls_ops->clo_fits_into(env, slice, need, io))
492 static struct cl_lock *cl_lock_lookup(const struct lu_env *env,
493 struct cl_object *obj,
494 const struct cl_io *io,
495 const struct cl_lock_descr *need)
497 struct cl_lock *lock;
498 struct cl_object_header *head;
502 head = cl_object_header(obj);
503 assert_spin_locked(&head->coh_lock_guard);
504 CS_LOCK_INC(obj, lookup);
505 cfs_list_for_each_entry(lock, &head->coh_locks, cll_linkage) {
508 matched = cl_lock_ext_match(&lock->cll_descr, need) &&
509 lock->cll_state < CLS_FREEING &&
510 lock->cll_error == 0 &&
511 !(lock->cll_flags & CLF_CANCELLED) &&
512 cl_lock_fits_into(env, lock, need, io);
513 CDEBUG(D_DLMTRACE, "has: "DDESCR"(%d) need: "DDESCR": %d\n",
514 PDESCR(&lock->cll_descr), lock->cll_state, PDESCR(need),
517 cl_lock_get_trust(lock);
518 CS_LOCK_INC(obj, hit);
526 * Returns a lock matching description \a need.
528 * This is the main entry point into the cl_lock caching interface. First, a
529 * cache (implemented as a per-object linked list) is consulted. If lock is
530 * found there, it is returned immediately. Otherwise new lock is allocated
531 * and returned. In any case, additional reference to lock is acquired.
533 * \see cl_object_find(), cl_page_find()
535 static struct cl_lock *cl_lock_find(const struct lu_env *env,
536 const struct cl_io *io,
537 const struct cl_lock_descr *need)
539 struct cl_object_header *head;
540 struct cl_object *obj;
541 struct cl_lock *lock;
546 head = cl_object_header(obj);
548 spin_lock(&head->coh_lock_guard);
549 lock = cl_lock_lookup(env, obj, io, need);
550 spin_unlock(&head->coh_lock_guard);
553 lock = cl_lock_alloc(env, obj, io, need);
555 struct cl_lock *ghost;
557 spin_lock(&head->coh_lock_guard);
558 ghost = cl_lock_lookup(env, obj, io, need);
560 cl_lock_get_trust(lock);
561 list_add_tail(&lock->cll_linkage,
563 spin_unlock(&head->coh_lock_guard);
564 CS_LOCK_INC(obj, busy);
566 spin_unlock(&head->coh_lock_guard);
568 * Other threads can acquire references to the
569 * top-lock through its sub-locks. Hence, it
570 * cannot be cl_lock_free()-ed immediately.
572 cl_lock_finish(env, lock);
581 * Returns existing lock matching given description. This is similar to
582 * cl_lock_find() except that no new lock is created, and returned lock is
583 * guaranteed to be in enum cl_lock_state::CLS_HELD state.
585 struct cl_lock *cl_lock_peek(const struct lu_env *env, const struct cl_io *io,
586 const struct cl_lock_descr *need,
587 const char *scope, const void *source)
589 struct cl_object_header *head;
590 struct cl_object *obj;
591 struct cl_lock *lock;
594 head = cl_object_header(obj);
597 spin_lock(&head->coh_lock_guard);
598 lock = cl_lock_lookup(env, obj, io, need);
599 spin_unlock(&head->coh_lock_guard);
603 cl_lock_mutex_get(env, lock);
604 if (lock->cll_state == CLS_INTRANSIT)
605 /* Don't care return value. */
606 cl_lock_state_wait(env, lock);
607 if (lock->cll_state == CLS_FREEING) {
608 cl_lock_mutex_put(env, lock);
609 cl_lock_put(env, lock);
612 } while (lock == NULL);
614 cl_lock_hold_add(env, lock, scope, source);
615 cl_lock_user_add(env, lock);
616 if (lock->cll_state == CLS_CACHED)
617 cl_use_try(env, lock, 1);
618 if (lock->cll_state == CLS_HELD) {
619 cl_lock_mutex_put(env, lock);
620 cl_lock_lockdep_acquire(env, lock, 0);
621 cl_lock_put(env, lock);
623 cl_unuse_try(env, lock);
624 cl_lock_unhold(env, lock, scope, source);
625 cl_lock_mutex_put(env, lock);
626 cl_lock_put(env, lock);
632 EXPORT_SYMBOL(cl_lock_peek);
635 * Returns a slice within a lock, corresponding to the given layer in the
640 const struct cl_lock_slice *cl_lock_at(const struct cl_lock *lock,
641 const struct lu_device_type *dtype)
643 const struct cl_lock_slice *slice;
645 LINVRNT(cl_lock_invariant_trusted(NULL, lock));
648 cfs_list_for_each_entry(slice, &lock->cll_layers, cls_linkage) {
649 if (slice->cls_obj->co_lu.lo_dev->ld_type == dtype)
654 EXPORT_SYMBOL(cl_lock_at);
656 static void cl_lock_mutex_tail(const struct lu_env *env, struct cl_lock *lock)
658 struct cl_thread_counters *counters;
660 counters = cl_lock_counters(env, lock);
662 counters->ctc_nr_locks_locked++;
663 lu_ref_add(&counters->ctc_locks_locked, "cll_guard", lock);
664 cl_lock_trace(D_TRACE, env, "got mutex", lock);
668 * Locks cl_lock object.
670 * This is used to manipulate cl_lock fields, and to serialize state
671 * transitions in the lock state machine.
673 * \post cl_lock_is_mutexed(lock)
675 * \see cl_lock_mutex_put()
677 void cl_lock_mutex_get(const struct lu_env *env, struct cl_lock *lock)
679 LINVRNT(cl_lock_invariant(env, lock));
681 if (lock->cll_guarder == current) {
682 LINVRNT(cl_lock_is_mutexed(lock));
683 LINVRNT(lock->cll_depth > 0);
685 struct cl_object_header *hdr;
686 struct cl_thread_info *info;
689 LINVRNT(lock->cll_guarder != current);
690 hdr = cl_object_header(lock->cll_descr.cld_obj);
692 * Check that mutices are taken in the bottom-to-top order.
694 info = cl_env_info(env);
695 for (i = 0; i < hdr->coh_nesting; ++i)
696 LASSERT(info->clt_counters[i].ctc_nr_locks_locked == 0);
697 mutex_lock_nested(&lock->cll_guard, hdr->coh_nesting);
698 lock->cll_guarder = current;
699 LINVRNT(lock->cll_depth == 0);
701 cl_lock_mutex_tail(env, lock);
703 EXPORT_SYMBOL(cl_lock_mutex_get);
706 * Try-locks cl_lock object.
708 * \retval 0 \a lock was successfully locked
710 * \retval -EBUSY \a lock cannot be locked right now
712 * \post ergo(result == 0, cl_lock_is_mutexed(lock))
714 * \see cl_lock_mutex_get()
716 int cl_lock_mutex_try(const struct lu_env *env, struct cl_lock *lock)
720 LINVRNT(cl_lock_invariant_trusted(env, lock));
724 if (lock->cll_guarder == current) {
725 LINVRNT(lock->cll_depth > 0);
726 cl_lock_mutex_tail(env, lock);
727 } else if (mutex_trylock(&lock->cll_guard)) {
728 LINVRNT(lock->cll_depth == 0);
729 lock->cll_guarder = current;
730 cl_lock_mutex_tail(env, lock);
735 EXPORT_SYMBOL(cl_lock_mutex_try);
738 {* Unlocks cl_lock object.
740 * \pre cl_lock_is_mutexed(lock)
742 * \see cl_lock_mutex_get()
744 void cl_lock_mutex_put(const struct lu_env *env, struct cl_lock *lock)
746 struct cl_thread_counters *counters;
748 LINVRNT(cl_lock_invariant(env, lock));
749 LINVRNT(cl_lock_is_mutexed(lock));
750 LINVRNT(lock->cll_guarder == current);
751 LINVRNT(lock->cll_depth > 0);
753 counters = cl_lock_counters(env, lock);
754 LINVRNT(counters->ctc_nr_locks_locked > 0);
756 cl_lock_trace(D_TRACE, env, "put mutex", lock);
757 lu_ref_del(&counters->ctc_locks_locked, "cll_guard", lock);
758 counters->ctc_nr_locks_locked--;
759 if (--lock->cll_depth == 0) {
760 lock->cll_guarder = NULL;
761 mutex_unlock(&lock->cll_guard);
764 EXPORT_SYMBOL(cl_lock_mutex_put);
767 * Returns true iff lock's mutex is owned by the current thread.
769 int cl_lock_is_mutexed(struct cl_lock *lock)
771 return lock->cll_guarder == current;
773 EXPORT_SYMBOL(cl_lock_is_mutexed);
776 * Returns number of cl_lock mutices held by the current thread (environment).
778 int cl_lock_nr_mutexed(const struct lu_env *env)
780 struct cl_thread_info *info;
785 * NOTE: if summation across all nesting levels (currently 2) proves
786 * too expensive, a summary counter can be added to
787 * struct cl_thread_info.
789 info = cl_env_info(env);
790 for (i = 0, locked = 0; i < ARRAY_SIZE(info->clt_counters); ++i)
791 locked += info->clt_counters[i].ctc_nr_locks_locked;
794 EXPORT_SYMBOL(cl_lock_nr_mutexed);
796 static void cl_lock_cancel0(const struct lu_env *env, struct cl_lock *lock)
798 LINVRNT(cl_lock_is_mutexed(lock));
799 LINVRNT(cl_lock_invariant(env, lock));
801 if (!(lock->cll_flags & CLF_CANCELLED)) {
802 const struct cl_lock_slice *slice;
804 lock->cll_flags |= CLF_CANCELLED;
805 cfs_list_for_each_entry_reverse(slice, &lock->cll_layers,
807 if (slice->cls_ops->clo_cancel != NULL)
808 slice->cls_ops->clo_cancel(env, slice);
814 static void cl_lock_delete0(const struct lu_env *env, struct cl_lock *lock)
816 struct cl_object_header *head;
817 const struct cl_lock_slice *slice;
819 LINVRNT(cl_lock_is_mutexed(lock));
820 LINVRNT(cl_lock_invariant(env, lock));
823 if (lock->cll_state < CLS_FREEING) {
826 LASSERT(lock->cll_state != CLS_INTRANSIT);
827 cl_lock_state_set(env, lock, CLS_FREEING);
829 head = cl_object_header(lock->cll_descr.cld_obj);
831 spin_lock(&head->coh_lock_guard);
832 in_cache = !list_empty(&lock->cll_linkage);
834 list_del_init(&lock->cll_linkage);
835 spin_unlock(&head->coh_lock_guard);
837 if (in_cache) /* coh_locks cache holds a refcount. */
838 cl_lock_put(env, lock);
841 * From now on, no new references to this lock can be acquired
842 * by cl_lock_lookup().
844 cfs_list_for_each_entry_reverse(slice, &lock->cll_layers,
846 if (slice->cls_ops->clo_delete != NULL)
847 slice->cls_ops->clo_delete(env, slice);
850 * From now on, no new references to this lock can be acquired
851 * by layer-specific means (like a pointer from struct
852 * ldlm_lock in osc, or a pointer from top-lock to sub-lock in
855 * Lock will be finally freed in cl_lock_put() when last of
856 * existing references goes away.
863 * Mod(ifie)s cl_lock::cll_holds counter for a given lock. Also, for a
864 * top-lock (nesting == 0) accounts for this modification in the per-thread
865 * debugging counters. Sub-lock holds can be released by a thread different
866 * from one that acquired it.
868 static void cl_lock_hold_mod(const struct lu_env *env, struct cl_lock *lock,
871 struct cl_thread_counters *counters;
872 enum clt_nesting_level nesting;
874 lock->cll_holds += delta;
875 nesting = cl_lock_nesting(lock);
876 if (nesting == CNL_TOP) {
877 counters = &cl_env_info(env)->clt_counters[CNL_TOP];
878 counters->ctc_nr_held += delta;
879 LASSERT(counters->ctc_nr_held >= 0);
884 * Mod(ifie)s cl_lock::cll_users counter for a given lock. See
885 * cl_lock_hold_mod() for the explanation of the debugging code.
887 static void cl_lock_used_mod(const struct lu_env *env, struct cl_lock *lock,
890 struct cl_thread_counters *counters;
891 enum clt_nesting_level nesting;
893 lock->cll_users += delta;
894 nesting = cl_lock_nesting(lock);
895 if (nesting == CNL_TOP) {
896 counters = &cl_env_info(env)->clt_counters[CNL_TOP];
897 counters->ctc_nr_used += delta;
898 LASSERT(counters->ctc_nr_used >= 0);
902 void cl_lock_hold_release(const struct lu_env *env, struct cl_lock *lock,
903 const char *scope, const void *source)
905 LINVRNT(cl_lock_is_mutexed(lock));
906 LINVRNT(cl_lock_invariant(env, lock));
907 LASSERT(lock->cll_holds > 0);
910 cl_lock_trace(D_DLMTRACE, env, "hold release lock", lock);
911 lu_ref_del(&lock->cll_holders, scope, source);
912 cl_lock_hold_mod(env, lock, -1);
913 if (lock->cll_holds == 0) {
914 CL_LOCK_ASSERT(lock->cll_state != CLS_HELD, env, lock);
915 if (lock->cll_descr.cld_mode == CLM_PHANTOM ||
916 lock->cll_descr.cld_mode == CLM_GROUP ||
917 lock->cll_state != CLS_CACHED)
919 * If lock is still phantom or grouplock when user is
920 * done with it---destroy the lock.
922 lock->cll_flags |= CLF_CANCELPEND|CLF_DOOMED;
923 if (lock->cll_flags & CLF_CANCELPEND) {
924 lock->cll_flags &= ~CLF_CANCELPEND;
925 cl_lock_cancel0(env, lock);
927 if (lock->cll_flags & CLF_DOOMED) {
928 /* no longer doomed: it's dead... Jim. */
929 lock->cll_flags &= ~CLF_DOOMED;
930 cl_lock_delete0(env, lock);
935 EXPORT_SYMBOL(cl_lock_hold_release);
938 * Waits until lock state is changed.
940 * This function is called with cl_lock mutex locked, atomically releases
941 * mutex and goes to sleep, waiting for a lock state change (signaled by
942 * cl_lock_signal()), and re-acquires the mutex before return.
944 * This function is used to wait until lock state machine makes some progress
945 * and to emulate synchronous operations on top of asynchronous lock
948 * \retval -EINTR wait was interrupted
950 * \retval 0 wait wasn't interrupted
952 * \pre cl_lock_is_mutexed(lock)
954 * \see cl_lock_signal()
956 int cl_lock_state_wait(const struct lu_env *env, struct cl_lock *lock)
963 LINVRNT(cl_lock_is_mutexed(lock));
964 LINVRNT(cl_lock_invariant(env, lock));
965 LASSERT(lock->cll_depth == 1);
966 LASSERT(lock->cll_state != CLS_FREEING); /* too late to wait */
968 cl_lock_trace(D_DLMTRACE, env, "state wait lock", lock);
969 result = lock->cll_error;
971 /* To avoid being interrupted by the 'non-fatal' signals
972 * (SIGCHLD, for instance), we'd block them temporarily.
974 blocked = cfs_block_sigsinv(LUSTRE_FATAL_SIGS);
976 init_waitqueue_entry_current(&waiter);
977 add_wait_queue(&lock->cll_wq, &waiter);
978 set_current_state(TASK_INTERRUPTIBLE);
979 cl_lock_mutex_put(env, lock);
981 LASSERT(cl_lock_nr_mutexed(env) == 0);
983 /* Returning ERESTARTSYS instead of EINTR so syscalls
984 * can be restarted if signals are pending here */
985 result = -ERESTARTSYS;
986 if (likely(!OBD_FAIL_CHECK(OBD_FAIL_LOCK_STATE_WAIT_INTR))) {
987 waitq_wait(&waiter, TASK_INTERRUPTIBLE);
988 if (!cfs_signal_pending())
992 cl_lock_mutex_get(env, lock);
993 set_current_state(TASK_RUNNING);
994 remove_wait_queue(&lock->cll_wq, &waiter);
996 /* Restore old blocked signals */
997 cfs_restore_sigs(blocked);
1001 EXPORT_SYMBOL(cl_lock_state_wait);
1003 static void cl_lock_state_signal(const struct lu_env *env, struct cl_lock *lock,
1004 enum cl_lock_state state)
1006 const struct cl_lock_slice *slice;
1009 LINVRNT(cl_lock_is_mutexed(lock));
1010 LINVRNT(cl_lock_invariant(env, lock));
1012 cfs_list_for_each_entry(slice, &lock->cll_layers, cls_linkage)
1013 if (slice->cls_ops->clo_state != NULL)
1014 slice->cls_ops->clo_state(env, slice, state);
1015 wake_up_all(&lock->cll_wq);
1020 * Notifies waiters that lock state changed.
1022 * Wakes up all waiters sleeping in cl_lock_state_wait(), also notifies all
1023 * layers about state change by calling cl_lock_operations::clo_state()
1026 void cl_lock_signal(const struct lu_env *env, struct cl_lock *lock)
1029 cl_lock_trace(D_DLMTRACE, env, "state signal lock", lock);
1030 cl_lock_state_signal(env, lock, lock->cll_state);
1033 EXPORT_SYMBOL(cl_lock_signal);
1036 * Changes lock state.
1038 * This function is invoked to notify layers that lock state changed, possible
1039 * as a result of an asynchronous event such as call-back reception.
1041 * \post lock->cll_state == state
1043 * \see cl_lock_operations::clo_state()
1045 void cl_lock_state_set(const struct lu_env *env, struct cl_lock *lock,
1046 enum cl_lock_state state)
1049 LASSERT(lock->cll_state <= state ||
1050 (lock->cll_state == CLS_CACHED &&
1051 (state == CLS_HELD || /* lock found in cache */
1052 state == CLS_NEW || /* sub-lock canceled */
1053 state == CLS_INTRANSIT)) ||
1054 /* lock is in transit state */
1055 lock->cll_state == CLS_INTRANSIT);
1057 if (lock->cll_state != state) {
1058 CS_LOCKSTATE_DEC(lock->cll_descr.cld_obj, lock->cll_state);
1059 CS_LOCKSTATE_INC(lock->cll_descr.cld_obj, state);
1061 cl_lock_state_signal(env, lock, state);
1062 lock->cll_state = state;
1066 EXPORT_SYMBOL(cl_lock_state_set);
1068 static int cl_unuse_try_internal(const struct lu_env *env, struct cl_lock *lock)
1070 const struct cl_lock_slice *slice;
1076 LINVRNT(cl_lock_is_mutexed(lock));
1077 LINVRNT(cl_lock_invariant(env, lock));
1078 LASSERT(lock->cll_state == CLS_INTRANSIT);
1081 cfs_list_for_each_entry_reverse(slice, &lock->cll_layers,
1083 if (slice->cls_ops->clo_unuse != NULL) {
1084 result = slice->cls_ops->clo_unuse(env, slice);
1089 LASSERT(result != -ENOSYS);
1090 } while (result == CLO_REPEAT);
1096 * Yanks lock from the cache (cl_lock_state::CLS_CACHED state) by calling
1097 * cl_lock_operations::clo_use() top-to-bottom to notify layers.
1098 * @atomic = 1, it must unuse the lock to recovery the lock to keep the
1099 * use process atomic
1101 int cl_use_try(const struct lu_env *env, struct cl_lock *lock, int atomic)
1103 const struct cl_lock_slice *slice;
1105 enum cl_lock_state state;
1108 cl_lock_trace(D_DLMTRACE, env, "use lock", lock);
1110 LASSERT(lock->cll_state == CLS_CACHED);
1111 if (lock->cll_error)
1112 RETURN(lock->cll_error);
1115 state = cl_lock_intransit(env, lock);
1116 cfs_list_for_each_entry(slice, &lock->cll_layers, cls_linkage) {
1117 if (slice->cls_ops->clo_use != NULL) {
1118 result = slice->cls_ops->clo_use(env, slice);
1123 LASSERT(result != -ENOSYS);
1125 LASSERTF(lock->cll_state == CLS_INTRANSIT, "Wrong state %d.\n",
1131 if (result == -ESTALE) {
1133 * ESTALE means sublock being cancelled
1134 * at this time, and set lock state to
1135 * be NEW here and ask the caller to repeat.
1138 result = CLO_REPEAT;
1141 /* @atomic means back-off-on-failure. */
1144 rc = cl_unuse_try_internal(env, lock);
1145 /* Vet the results. */
1146 if (rc < 0 && result > 0)
1151 cl_lock_extransit(env, lock, state);
1154 EXPORT_SYMBOL(cl_use_try);
1157 * Helper for cl_enqueue_try() that calls ->clo_enqueue() across all layers
1160 static int cl_enqueue_kick(const struct lu_env *env,
1161 struct cl_lock *lock,
1162 struct cl_io *io, __u32 flags)
1165 const struct cl_lock_slice *slice;
1169 cfs_list_for_each_entry(slice, &lock->cll_layers, cls_linkage) {
1170 if (slice->cls_ops->clo_enqueue != NULL) {
1171 result = slice->cls_ops->clo_enqueue(env,
1177 LASSERT(result != -ENOSYS);
1182 * Tries to enqueue a lock.
1184 * This function is called repeatedly by cl_enqueue() until either lock is
1185 * enqueued, or error occurs. This function does not block waiting for
1186 * networking communication to complete.
1188 * \post ergo(result == 0, lock->cll_state == CLS_ENQUEUED ||
1189 * lock->cll_state == CLS_HELD)
1191 * \see cl_enqueue() cl_lock_operations::clo_enqueue()
1192 * \see cl_lock_state::CLS_ENQUEUED
1194 int cl_enqueue_try(const struct lu_env *env, struct cl_lock *lock,
1195 struct cl_io *io, __u32 flags)
1200 cl_lock_trace(D_DLMTRACE, env, "enqueue lock", lock);
1202 LINVRNT(cl_lock_is_mutexed(lock));
1204 result = lock->cll_error;
1208 switch (lock->cll_state) {
1210 cl_lock_state_set(env, lock, CLS_QUEUING);
1214 result = cl_enqueue_kick(env, lock, io, flags);
1215 /* For AGL case, the cl_lock::cll_state may
1216 * become CLS_HELD already. */
1217 if (result == 0 && lock->cll_state == CLS_QUEUING)
1218 cl_lock_state_set(env, lock, CLS_ENQUEUED);
1221 LASSERT(cl_lock_is_intransit(lock));
1225 /* yank lock from the cache. */
1226 result = cl_use_try(env, lock, 0);
1235 * impossible, only held locks with increased
1236 * ->cll_holds can be enqueued, and they cannot be
1241 } while (result == CLO_REPEAT);
1244 EXPORT_SYMBOL(cl_enqueue_try);
1247 * Cancel the conflicting lock found during previous enqueue.
1249 * \retval 0 conflicting lock has been canceled.
1250 * \retval -ve error code.
1252 int cl_lock_enqueue_wait(const struct lu_env *env,
1253 struct cl_lock *lock,
1256 struct cl_lock *conflict;
1260 LASSERT(cl_lock_is_mutexed(lock));
1261 LASSERT(lock->cll_state == CLS_QUEUING);
1262 LASSERT(lock->cll_conflict != NULL);
1264 conflict = lock->cll_conflict;
1265 lock->cll_conflict = NULL;
1267 cl_lock_mutex_put(env, lock);
1268 LASSERT(cl_lock_nr_mutexed(env) == 0);
1270 cl_lock_mutex_get(env, conflict);
1271 cl_lock_trace(D_DLMTRACE, env, "enqueue wait", conflict);
1272 cl_lock_cancel(env, conflict);
1273 cl_lock_delete(env, conflict);
1275 while (conflict->cll_state != CLS_FREEING) {
1276 rc = cl_lock_state_wait(env, conflict);
1280 cl_lock_mutex_put(env, conflict);
1281 lu_ref_del(&conflict->cll_reference, "cancel-wait", lock);
1282 cl_lock_put(env, conflict);
1285 cl_lock_mutex_get(env, lock);
1290 EXPORT_SYMBOL(cl_lock_enqueue_wait);
1292 static int cl_enqueue_locked(const struct lu_env *env, struct cl_lock *lock,
1293 struct cl_io *io, __u32 enqflags)
1299 LINVRNT(cl_lock_is_mutexed(lock));
1300 LINVRNT(cl_lock_invariant(env, lock));
1301 LASSERT(lock->cll_holds > 0);
1303 cl_lock_user_add(env, lock);
1305 result = cl_enqueue_try(env, lock, io, enqflags);
1306 if (result == CLO_WAIT) {
1307 if (lock->cll_conflict != NULL)
1308 result = cl_lock_enqueue_wait(env, lock, 1);
1310 result = cl_lock_state_wait(env, lock);
1317 cl_unuse_try(env, lock);
1318 LASSERT(ergo(result == 0 && !(enqflags & CEF_AGL),
1319 lock->cll_state == CLS_ENQUEUED ||
1320 lock->cll_state == CLS_HELD));
1327 * \pre current thread or io owns a hold on lock.
1329 * \post ergo(result == 0, lock->users increased)
1330 * \post ergo(result == 0, lock->cll_state == CLS_ENQUEUED ||
1331 * lock->cll_state == CLS_HELD)
1333 int cl_enqueue(const struct lu_env *env, struct cl_lock *lock,
1334 struct cl_io *io, __u32 enqflags)
1340 cl_lock_lockdep_acquire(env, lock, enqflags);
1341 cl_lock_mutex_get(env, lock);
1342 result = cl_enqueue_locked(env, lock, io, enqflags);
1343 cl_lock_mutex_put(env, lock);
1345 cl_lock_lockdep_release(env, lock);
1346 LASSERT(ergo(result == 0, lock->cll_state == CLS_ENQUEUED ||
1347 lock->cll_state == CLS_HELD));
1350 EXPORT_SYMBOL(cl_enqueue);
1353 * Tries to unlock a lock.
1355 * This function is called to release underlying resource:
1356 * 1. for top lock, the resource is sublocks it held;
1357 * 2. for sublock, the resource is the reference to dlmlock.
1359 * cl_unuse_try is a one-shot operation, so it must NOT return CLO_WAIT.
1361 * \see cl_unuse() cl_lock_operations::clo_unuse()
1362 * \see cl_lock_state::CLS_CACHED
1364 int cl_unuse_try(const struct lu_env *env, struct cl_lock *lock)
1367 enum cl_lock_state state = CLS_NEW;
1370 cl_lock_trace(D_DLMTRACE, env, "unuse lock", lock);
1372 if (lock->cll_users > 1) {
1373 cl_lock_user_del(env, lock);
1377 /* Only if the lock is in CLS_HELD or CLS_ENQUEUED state, it can hold
1378 * underlying resources. */
1379 if (!(lock->cll_state == CLS_HELD || lock->cll_state == CLS_ENQUEUED)) {
1380 cl_lock_user_del(env, lock);
1385 * New lock users (->cll_users) are not protecting unlocking
1386 * from proceeding. From this point, lock eventually reaches
1387 * CLS_CACHED, is reinitialized to CLS_NEW or fails into
1390 state = cl_lock_intransit(env, lock);
1392 result = cl_unuse_try_internal(env, lock);
1393 LASSERT(lock->cll_state == CLS_INTRANSIT);
1394 LASSERT(result != CLO_WAIT);
1395 cl_lock_user_del(env, lock);
1396 if (result == 0 || result == -ESTALE) {
1398 * Return lock back to the cache. This is the only
1399 * place where lock is moved into CLS_CACHED state.
1401 * If one of ->clo_unuse() methods returned -ESTALE, lock
1402 * cannot be placed into cache and has to be
1403 * re-initialized. This happens e.g., when a sub-lock was
1404 * canceled while unlocking was in progress.
1406 if (state == CLS_HELD && result == 0)
1410 cl_lock_extransit(env, lock, state);
1413 * Hide -ESTALE error.
1414 * If the lock is a glimpse lock, and it has multiple
1415 * stripes. Assuming that one of its sublock returned -ENAVAIL,
1416 * and other sublocks are matched write locks. In this case,
1417 * we can't set this lock to error because otherwise some of
1418 * its sublocks may not be canceled. This causes some dirty
1419 * pages won't be written to OSTs. -jay
1423 CERROR("result = %d, this is unlikely!\n", result);
1425 cl_lock_extransit(env, lock, state);
1427 RETURN(result ?: lock->cll_error);
1429 EXPORT_SYMBOL(cl_unuse_try);
1431 static void cl_unuse_locked(const struct lu_env *env, struct cl_lock *lock)
1436 result = cl_unuse_try(env, lock);
1438 CL_LOCK_DEBUG(D_ERROR, env, lock, "unuse return %d\n", result);
1446 void cl_unuse(const struct lu_env *env, struct cl_lock *lock)
1449 cl_lock_mutex_get(env, lock);
1450 cl_unuse_locked(env, lock);
1451 cl_lock_mutex_put(env, lock);
1452 cl_lock_lockdep_release(env, lock);
1455 EXPORT_SYMBOL(cl_unuse);
1458 * Tries to wait for a lock.
1460 * This function is called repeatedly by cl_wait() until either lock is
1461 * granted, or error occurs. This function does not block waiting for network
1462 * communication to complete.
1464 * \see cl_wait() cl_lock_operations::clo_wait()
1465 * \see cl_lock_state::CLS_HELD
1467 int cl_wait_try(const struct lu_env *env, struct cl_lock *lock)
1469 const struct cl_lock_slice *slice;
1473 cl_lock_trace(D_DLMTRACE, env, "wait lock try", lock);
1475 LINVRNT(cl_lock_is_mutexed(lock));
1476 LINVRNT(cl_lock_invariant(env, lock));
1477 LASSERTF(lock->cll_state == CLS_QUEUING ||
1478 lock->cll_state == CLS_ENQUEUED ||
1479 lock->cll_state == CLS_HELD ||
1480 lock->cll_state == CLS_INTRANSIT,
1481 "lock state: %d\n", lock->cll_state);
1482 LASSERT(lock->cll_users > 0);
1483 LASSERT(lock->cll_holds > 0);
1485 result = lock->cll_error;
1489 if (cl_lock_is_intransit(lock)) {
1494 if (lock->cll_state == CLS_HELD)
1499 cfs_list_for_each_entry(slice, &lock->cll_layers, cls_linkage) {
1500 if (slice->cls_ops->clo_wait != NULL) {
1501 result = slice->cls_ops->clo_wait(env, slice);
1506 LASSERT(result != -ENOSYS);
1508 LASSERT(lock->cll_state != CLS_INTRANSIT);
1509 cl_lock_state_set(env, lock, CLS_HELD);
1511 } while (result == CLO_REPEAT);
1514 EXPORT_SYMBOL(cl_wait_try);
1517 * Waits until enqueued lock is granted.
1519 * \pre current thread or io owns a hold on the lock
1520 * \pre ergo(result == 0, lock->cll_state == CLS_ENQUEUED ||
1521 * lock->cll_state == CLS_HELD)
1523 * \post ergo(result == 0, lock->cll_state == CLS_HELD)
1525 int cl_wait(const struct lu_env *env, struct cl_lock *lock)
1530 cl_lock_mutex_get(env, lock);
1532 LINVRNT(cl_lock_invariant(env, lock));
1533 LASSERTF(lock->cll_state == CLS_ENQUEUED || lock->cll_state == CLS_HELD,
1534 "Wrong state %d \n", lock->cll_state);
1535 LASSERT(lock->cll_holds > 0);
1538 result = cl_wait_try(env, lock);
1539 if (result == CLO_WAIT) {
1540 result = cl_lock_state_wait(env, lock);
1547 cl_unuse_try(env, lock);
1548 cl_lock_lockdep_release(env, lock);
1550 cl_lock_trace(D_DLMTRACE, env, "wait lock", lock);
1551 cl_lock_mutex_put(env, lock);
1552 LASSERT(ergo(result == 0, lock->cll_state == CLS_HELD));
1555 EXPORT_SYMBOL(cl_wait);
1558 * Executes cl_lock_operations::clo_weigh(), and sums results to estimate lock
1561 unsigned long cl_lock_weigh(const struct lu_env *env, struct cl_lock *lock)
1563 const struct cl_lock_slice *slice;
1564 unsigned long pound;
1565 unsigned long ounce;
1568 LINVRNT(cl_lock_is_mutexed(lock));
1569 LINVRNT(cl_lock_invariant(env, lock));
1572 cfs_list_for_each_entry_reverse(slice, &lock->cll_layers, cls_linkage) {
1573 if (slice->cls_ops->clo_weigh != NULL) {
1574 ounce = slice->cls_ops->clo_weigh(env, slice);
1576 if (pound < ounce) /* over-weight^Wflow */
1582 EXPORT_SYMBOL(cl_lock_weigh);
1585 * Notifies layers that lock description changed.
1587 * The server can grant client a lock different from one that was requested
1588 * (e.g., larger in extent). This method is called when actually granted lock
1589 * description becomes known to let layers to accommodate for changed lock
1592 * \see cl_lock_operations::clo_modify()
1594 int cl_lock_modify(const struct lu_env *env, struct cl_lock *lock,
1595 const struct cl_lock_descr *desc)
1597 const struct cl_lock_slice *slice;
1598 struct cl_object *obj = lock->cll_descr.cld_obj;
1599 struct cl_object_header *hdr = cl_object_header(obj);
1603 cl_lock_trace(D_DLMTRACE, env, "modify lock", lock);
1604 /* don't allow object to change */
1605 LASSERT(obj == desc->cld_obj);
1606 LINVRNT(cl_lock_is_mutexed(lock));
1607 LINVRNT(cl_lock_invariant(env, lock));
1609 cfs_list_for_each_entry_reverse(slice, &lock->cll_layers, cls_linkage) {
1610 if (slice->cls_ops->clo_modify != NULL) {
1611 result = slice->cls_ops->clo_modify(env, slice, desc);
1616 CL_LOCK_DEBUG(D_DLMTRACE, env, lock, " -> "DDESCR"@"DFID"\n",
1617 PDESCR(desc), PFID(lu_object_fid(&desc->cld_obj->co_lu)));
1619 * Just replace description in place. Nothing more is needed for
1620 * now. If locks were indexed according to their extent and/or mode,
1621 * that index would have to be updated here.
1623 spin_lock(&hdr->coh_lock_guard);
1624 lock->cll_descr = *desc;
1625 spin_unlock(&hdr->coh_lock_guard);
1628 EXPORT_SYMBOL(cl_lock_modify);
1631 * Initializes lock closure with a given origin.
1633 * \see cl_lock_closure
1635 void cl_lock_closure_init(const struct lu_env *env,
1636 struct cl_lock_closure *closure,
1637 struct cl_lock *origin, int wait)
1639 LINVRNT(cl_lock_is_mutexed(origin));
1640 LINVRNT(cl_lock_invariant(env, origin));
1642 CFS_INIT_LIST_HEAD(&closure->clc_list);
1643 closure->clc_origin = origin;
1644 closure->clc_wait = wait;
1645 closure->clc_nr = 0;
1647 EXPORT_SYMBOL(cl_lock_closure_init);
1650 * Builds a closure of \a lock.
1652 * Building of a closure consists of adding initial lock (\a lock) into it,
1653 * and calling cl_lock_operations::clo_closure() methods of \a lock. These
1654 * methods might call cl_lock_closure_build() recursively again, adding more
1655 * locks to the closure, etc.
1657 * \see cl_lock_closure
1659 int cl_lock_closure_build(const struct lu_env *env, struct cl_lock *lock,
1660 struct cl_lock_closure *closure)
1662 const struct cl_lock_slice *slice;
1666 LINVRNT(cl_lock_is_mutexed(closure->clc_origin));
1667 LINVRNT(cl_lock_invariant(env, closure->clc_origin));
1669 result = cl_lock_enclosure(env, lock, closure);
1671 cfs_list_for_each_entry(slice, &lock->cll_layers, cls_linkage) {
1672 if (slice->cls_ops->clo_closure != NULL) {
1673 result = slice->cls_ops->clo_closure(env, slice,
1681 cl_lock_disclosure(env, closure);
1684 EXPORT_SYMBOL(cl_lock_closure_build);
1687 * Adds new lock to a closure.
1689 * Try-locks \a lock and if succeeded, adds it to the closure (never more than
1690 * once). If try-lock failed, returns CLO_REPEAT, after optionally waiting
1691 * until next try-lock is likely to succeed.
1693 int cl_lock_enclosure(const struct lu_env *env, struct cl_lock *lock,
1694 struct cl_lock_closure *closure)
1698 cl_lock_trace(D_DLMTRACE, env, "enclosure lock", lock);
1699 if (!cl_lock_mutex_try(env, lock)) {
1701 * If lock->cll_inclosure is not empty, lock is already in
1704 if (cfs_list_empty(&lock->cll_inclosure)) {
1705 cl_lock_get_trust(lock);
1706 lu_ref_add(&lock->cll_reference, "closure", closure);
1707 cfs_list_add(&lock->cll_inclosure, &closure->clc_list);
1710 cl_lock_mutex_put(env, lock);
1713 cl_lock_disclosure(env, closure);
1714 if (closure->clc_wait) {
1715 cl_lock_get_trust(lock);
1716 lu_ref_add(&lock->cll_reference, "closure-w", closure);
1717 cl_lock_mutex_put(env, closure->clc_origin);
1719 LASSERT(cl_lock_nr_mutexed(env) == 0);
1720 cl_lock_mutex_get(env, lock);
1721 cl_lock_mutex_put(env, lock);
1723 cl_lock_mutex_get(env, closure->clc_origin);
1724 lu_ref_del(&lock->cll_reference, "closure-w", closure);
1725 cl_lock_put(env, lock);
1727 result = CLO_REPEAT;
1731 EXPORT_SYMBOL(cl_lock_enclosure);
1733 /** Releases mutices of enclosed locks. */
1734 void cl_lock_disclosure(const struct lu_env *env,
1735 struct cl_lock_closure *closure)
1737 struct cl_lock *scan;
1738 struct cl_lock *temp;
1740 cl_lock_trace(D_DLMTRACE, env, "disclosure lock", closure->clc_origin);
1741 cfs_list_for_each_entry_safe(scan, temp, &closure->clc_list,
1743 cfs_list_del_init(&scan->cll_inclosure);
1744 cl_lock_mutex_put(env, scan);
1745 lu_ref_del(&scan->cll_reference, "closure", closure);
1746 cl_lock_put(env, scan);
1749 LASSERT(closure->clc_nr == 0);
1751 EXPORT_SYMBOL(cl_lock_disclosure);
1753 /** Finalizes a closure. */
1754 void cl_lock_closure_fini(struct cl_lock_closure *closure)
1756 LASSERT(closure->clc_nr == 0);
1757 LASSERT(cfs_list_empty(&closure->clc_list));
1759 EXPORT_SYMBOL(cl_lock_closure_fini);
1762 * Destroys this lock. Notifies layers (bottom-to-top) that lock is being
1763 * destroyed, then destroy the lock. If there are holds on the lock, postpone
1764 * destruction until all holds are released. This is called when a decision is
1765 * made to destroy the lock in the future. E.g., when a blocking AST is
1766 * received on it, or fatal communication error happens.
1768 * Caller must have a reference on this lock to prevent a situation, when
1769 * deleted lock lingers in memory for indefinite time, because nobody calls
1770 * cl_lock_put() to finish it.
1772 * \pre atomic_read(&lock->cll_ref) > 0
1773 * \pre ergo(cl_lock_nesting(lock) == CNL_TOP,
1774 * cl_lock_nr_mutexed(env) == 1)
1775 * [i.e., if a top-lock is deleted, mutices of no other locks can be
1776 * held, as deletion of sub-locks might require releasing a top-lock
1779 * \see cl_lock_operations::clo_delete()
1780 * \see cl_lock::cll_holds
1782 void cl_lock_delete(const struct lu_env *env, struct cl_lock *lock)
1784 LINVRNT(cl_lock_is_mutexed(lock));
1785 LINVRNT(cl_lock_invariant(env, lock));
1786 LASSERT(ergo(cl_lock_nesting(lock) == CNL_TOP,
1787 cl_lock_nr_mutexed(env) == 1));
1790 cl_lock_trace(D_DLMTRACE, env, "delete lock", lock);
1791 if (lock->cll_holds == 0)
1792 cl_lock_delete0(env, lock);
1794 lock->cll_flags |= CLF_DOOMED;
1797 EXPORT_SYMBOL(cl_lock_delete);
1800 * Mark lock as irrecoverably failed, and mark it for destruction. This
1801 * happens when, e.g., server fails to grant a lock to us, or networking
1804 * \pre atomic_read(&lock->cll_ref) > 0
1806 * \see clo_lock_delete()
1807 * \see cl_lock::cll_holds
1809 void cl_lock_error(const struct lu_env *env, struct cl_lock *lock, int error)
1811 LINVRNT(cl_lock_is_mutexed(lock));
1812 LINVRNT(cl_lock_invariant(env, lock));
1815 if (lock->cll_error == 0 && error != 0) {
1816 cl_lock_trace(D_DLMTRACE, env, "set lock error", lock);
1817 lock->cll_error = error;
1818 cl_lock_signal(env, lock);
1819 cl_lock_cancel(env, lock);
1820 cl_lock_delete(env, lock);
1824 EXPORT_SYMBOL(cl_lock_error);
1827 * Cancels this lock. Notifies layers
1828 * (bottom-to-top) that lock is being cancelled, then destroy the lock. If
1829 * there are holds on the lock, postpone cancellation until
1830 * all holds are released.
1832 * Cancellation notification is delivered to layers at most once.
1834 * \see cl_lock_operations::clo_cancel()
1835 * \see cl_lock::cll_holds
1837 void cl_lock_cancel(const struct lu_env *env, struct cl_lock *lock)
1839 LINVRNT(cl_lock_is_mutexed(lock));
1840 LINVRNT(cl_lock_invariant(env, lock));
1843 cl_lock_trace(D_DLMTRACE, env, "cancel lock", lock);
1844 if (lock->cll_holds == 0)
1845 cl_lock_cancel0(env, lock);
1847 lock->cll_flags |= CLF_CANCELPEND;
1850 EXPORT_SYMBOL(cl_lock_cancel);
1853 * Finds an existing lock covering given index and optionally different from a
1854 * given \a except lock.
1856 struct cl_lock *cl_lock_at_pgoff(const struct lu_env *env,
1857 struct cl_object *obj, pgoff_t index,
1858 struct cl_lock *except,
1859 int pending, int canceld)
1861 struct cl_object_header *head;
1862 struct cl_lock *scan;
1863 struct cl_lock *lock;
1864 struct cl_lock_descr *need;
1868 head = cl_object_header(obj);
1869 need = &cl_env_info(env)->clt_descr;
1872 need->cld_mode = CLM_READ; /* CLM_READ matches both READ & WRITE, but
1874 need->cld_start = need->cld_end = index;
1875 need->cld_enq_flags = 0;
1877 spin_lock(&head->coh_lock_guard);
1878 /* It is fine to match any group lock since there could be only one
1879 * with a uniq gid and it conflicts with all other lock modes too */
1880 cfs_list_for_each_entry(scan, &head->coh_locks, cll_linkage) {
1881 if (scan != except &&
1882 (scan->cll_descr.cld_mode == CLM_GROUP ||
1883 cl_lock_ext_match(&scan->cll_descr, need)) &&
1884 scan->cll_state >= CLS_HELD &&
1885 scan->cll_state < CLS_FREEING &&
1887 * This check is racy as the lock can be canceled right
1888 * after it is done, but this is fine, because page exists
1891 (canceld || !(scan->cll_flags & CLF_CANCELLED)) &&
1892 (pending || !(scan->cll_flags & CLF_CANCELPEND))) {
1893 /* Don't increase cs_hit here since this
1894 * is just a helper function. */
1895 cl_lock_get_trust(scan);
1900 spin_unlock(&head->coh_lock_guard);
1903 EXPORT_SYMBOL(cl_lock_at_pgoff);
1906 * Eliminate all locks for a given object.
1908 * Caller has to guarantee that no lock is in active use.
1910 * \param cancel when this is set, cl_locks_prune() cancels locks before
1913 void cl_locks_prune(const struct lu_env *env, struct cl_object *obj, int cancel)
1915 struct cl_object_header *head;
1916 struct cl_lock *lock;
1919 head = cl_object_header(obj);
1921 spin_lock(&head->coh_lock_guard);
1922 while (!cfs_list_empty(&head->coh_locks)) {
1923 lock = container_of(head->coh_locks.next,
1924 struct cl_lock, cll_linkage);
1925 cl_lock_get_trust(lock);
1926 spin_unlock(&head->coh_lock_guard);
1927 lu_ref_add(&lock->cll_reference, "prune", current);
1930 cl_lock_mutex_get(env, lock);
1931 if (lock->cll_state < CLS_FREEING) {
1932 LASSERT(lock->cll_users <= 1);
1933 if (unlikely(lock->cll_users == 1)) {
1934 struct l_wait_info lwi = { 0 };
1936 cl_lock_mutex_put(env, lock);
1937 l_wait_event(lock->cll_wq,
1938 lock->cll_users == 0,
1944 cl_lock_cancel(env, lock);
1945 cl_lock_delete(env, lock);
1947 cl_lock_mutex_put(env, lock);
1948 lu_ref_del(&lock->cll_reference, "prune", current);
1949 cl_lock_put(env, lock);
1950 spin_lock(&head->coh_lock_guard);
1952 spin_unlock(&head->coh_lock_guard);
1955 EXPORT_SYMBOL(cl_locks_prune);
1957 static struct cl_lock *cl_lock_hold_mutex(const struct lu_env *env,
1958 const struct cl_io *io,
1959 const struct cl_lock_descr *need,
1960 const char *scope, const void *source)
1962 struct cl_lock *lock;
1967 lock = cl_lock_find(env, io, need);
1970 cl_lock_mutex_get(env, lock);
1971 if (lock->cll_state < CLS_FREEING &&
1972 !(lock->cll_flags & CLF_CANCELLED)) {
1973 cl_lock_hold_mod(env, lock, +1);
1974 lu_ref_add(&lock->cll_holders, scope, source);
1975 lu_ref_add(&lock->cll_reference, scope, source);
1978 cl_lock_mutex_put(env, lock);
1979 cl_lock_put(env, lock);
1985 * Returns a lock matching \a need description with a reference and a hold on
1988 * This is much like cl_lock_find(), except that cl_lock_hold() additionally
1989 * guarantees that lock is not in the CLS_FREEING state on return.
1991 struct cl_lock *cl_lock_hold(const struct lu_env *env, const struct cl_io *io,
1992 const struct cl_lock_descr *need,
1993 const char *scope, const void *source)
1995 struct cl_lock *lock;
1999 lock = cl_lock_hold_mutex(env, io, need, scope, source);
2001 cl_lock_mutex_put(env, lock);
2004 EXPORT_SYMBOL(cl_lock_hold);
2007 * Main high-level entry point of cl_lock interface that finds existing or
2008 * enqueues new lock matching given description.
2010 struct cl_lock *cl_lock_request(const struct lu_env *env, struct cl_io *io,
2011 const struct cl_lock_descr *need,
2012 const char *scope, const void *source)
2014 struct cl_lock *lock;
2016 __u32 enqflags = need->cld_enq_flags;
2020 lock = cl_lock_hold_mutex(env, io, need, scope, source);
2024 rc = cl_enqueue_locked(env, lock, io, enqflags);
2026 if (cl_lock_fits_into(env, lock, need, io)) {
2027 if (!(enqflags & CEF_AGL)) {
2028 cl_lock_mutex_put(env, lock);
2029 cl_lock_lockdep_acquire(env, lock,
2035 cl_unuse_locked(env, lock);
2037 cl_lock_trace(D_DLMTRACE, env,
2038 rc <= 0 ? "enqueue failed" : "agl succeed", lock);
2039 cl_lock_hold_release(env, lock, scope, source);
2040 cl_lock_mutex_put(env, lock);
2041 lu_ref_del(&lock->cll_reference, scope, source);
2042 cl_lock_put(env, lock);
2044 LASSERT(enqflags & CEF_AGL);
2046 } else if (rc != 0) {
2052 EXPORT_SYMBOL(cl_lock_request);
2055 * Adds a hold to a known lock.
2057 void cl_lock_hold_add(const struct lu_env *env, struct cl_lock *lock,
2058 const char *scope, const void *source)
2060 LINVRNT(cl_lock_is_mutexed(lock));
2061 LINVRNT(cl_lock_invariant(env, lock));
2062 LASSERT(lock->cll_state != CLS_FREEING);
2066 cl_lock_hold_mod(env, lock, +1);
2067 lu_ref_add(&lock->cll_holders, scope, source);
2068 lu_ref_add(&lock->cll_reference, scope, source);
2071 EXPORT_SYMBOL(cl_lock_hold_add);
2074 * Releases a hold and a reference on a lock, on which caller acquired a
2077 void cl_lock_unhold(const struct lu_env *env, struct cl_lock *lock,
2078 const char *scope, const void *source)
2080 LINVRNT(cl_lock_invariant(env, lock));
2082 cl_lock_hold_release(env, lock, scope, source);
2083 lu_ref_del(&lock->cll_reference, scope, source);
2084 cl_lock_put(env, lock);
2087 EXPORT_SYMBOL(cl_lock_unhold);
2090 * Releases a hold and a reference on a lock, obtained by cl_lock_hold().
2092 void cl_lock_release(const struct lu_env *env, struct cl_lock *lock,
2093 const char *scope, const void *source)
2095 LINVRNT(cl_lock_invariant(env, lock));
2097 cl_lock_trace(D_DLMTRACE, env, "release lock", lock);
2098 cl_lock_mutex_get(env, lock);
2099 cl_lock_hold_release(env, lock, scope, source);
2100 cl_lock_mutex_put(env, lock);
2101 lu_ref_del(&lock->cll_reference, scope, source);
2102 cl_lock_put(env, lock);
2105 EXPORT_SYMBOL(cl_lock_release);
2107 void cl_lock_user_add(const struct lu_env *env, struct cl_lock *lock)
2109 LINVRNT(cl_lock_is_mutexed(lock));
2110 LINVRNT(cl_lock_invariant(env, lock));
2113 cl_lock_used_mod(env, lock, +1);
2116 EXPORT_SYMBOL(cl_lock_user_add);
2118 void cl_lock_user_del(const struct lu_env *env, struct cl_lock *lock)
2120 LINVRNT(cl_lock_is_mutexed(lock));
2121 LINVRNT(cl_lock_invariant(env, lock));
2122 LASSERT(lock->cll_users > 0);
2125 cl_lock_used_mod(env, lock, -1);
2126 if (lock->cll_users == 0)
2127 wake_up_all(&lock->cll_wq);
2130 EXPORT_SYMBOL(cl_lock_user_del);
2132 const char *cl_lock_mode_name(const enum cl_lock_mode mode)
2134 static const char *names[] = {
2135 [CLM_PHANTOM] = "P",
2140 CLASSERT(CLM_MAX == ARRAY_SIZE(names));
2143 EXPORT_SYMBOL(cl_lock_mode_name);
2146 * Prints human readable representation of a lock description.
2148 void cl_lock_descr_print(const struct lu_env *env, void *cookie,
2149 lu_printer_t printer,
2150 const struct cl_lock_descr *descr)
2152 const struct lu_fid *fid;
2154 fid = lu_object_fid(&descr->cld_obj->co_lu);
2155 (*printer)(env, cookie, DDESCR"@"DFID, PDESCR(descr), PFID(fid));
2157 EXPORT_SYMBOL(cl_lock_descr_print);
2160 * Prints human readable representation of \a lock to the \a f.
2162 void cl_lock_print(const struct lu_env *env, void *cookie,
2163 lu_printer_t printer, const struct cl_lock *lock)
2165 const struct cl_lock_slice *slice;
2166 (*printer)(env, cookie, "lock@%p[%d %d %d %d %d %08lx] ",
2167 lock, atomic_read(&lock->cll_ref),
2168 lock->cll_state, lock->cll_error, lock->cll_holds,
2169 lock->cll_users, lock->cll_flags);
2170 cl_lock_descr_print(env, cookie, printer, &lock->cll_descr);
2171 (*printer)(env, cookie, " {\n");
2173 cfs_list_for_each_entry(slice, &lock->cll_layers, cls_linkage) {
2174 (*printer)(env, cookie, " %s@%p: ",
2175 slice->cls_obj->co_lu.lo_dev->ld_type->ldt_name,
2177 if (slice->cls_ops->clo_print != NULL)
2178 slice->cls_ops->clo_print(env, cookie, printer, slice);
2179 (*printer)(env, cookie, "\n");
2181 (*printer)(env, cookie, "} lock@%p\n", lock);
2183 EXPORT_SYMBOL(cl_lock_print);
2185 int cl_lock_init(void)
2187 return lu_kmem_init(cl_lock_caches);
2190 void cl_lock_fini(void)
2192 lu_kmem_fini(cl_lock_caches);