diff options
Diffstat (limited to 'drivers/staging/lustre/lustre/obdclass/cl_lock.c')
-rw-r--r-- | drivers/staging/lustre/lustre/obdclass/cl_lock.c | 2086 |
1 files changed, 73 insertions, 2013 deletions
diff --git a/drivers/staging/lustre/lustre/obdclass/cl_lock.c b/drivers/staging/lustre/lustre/obdclass/cl_lock.c index aec644eb4db9..26a576b63a72 100644 --- a/drivers/staging/lustre/lustre/obdclass/cl_lock.c +++ b/drivers/staging/lustre/lustre/obdclass/cl_lock.c @@ -36,6 +36,7 @@ * Client Extent Lock. * * Author: Nikita Danilov <nikita.danilov@sun.com> + * Author: Jinshan Xiong <jinshan.xiong@intel.com> */ #define DEBUG_SUBSYSTEM S_CLASS @@ -47,138 +48,18 @@ #include "../include/cl_object.h" #include "cl_internal.h" -/** Lock class of cl_lock::cll_guard */ -static struct lock_class_key cl_lock_guard_class; -static struct kmem_cache *cl_lock_kmem; - -static struct lu_kmem_descr cl_lock_caches[] = { - { - .ckd_cache = &cl_lock_kmem, - .ckd_name = "cl_lock_kmem", - .ckd_size = sizeof (struct cl_lock) - }, - { - .ckd_cache = NULL - } -}; - -#define CS_LOCK_INC(o, item) -#define CS_LOCK_DEC(o, item) -#define CS_LOCKSTATE_INC(o, state) -#define CS_LOCKSTATE_DEC(o, state) - -/** - * Basic lock invariant that is maintained at all times. Caller either has a - * reference to \a lock, or somehow assures that \a lock cannot be freed. - * - * \see cl_lock_invariant() - */ -static int cl_lock_invariant_trusted(const struct lu_env *env, - const struct cl_lock *lock) -{ - return ergo(lock->cll_state == CLS_FREEING, lock->cll_holds == 0) && - atomic_read(&lock->cll_ref) >= lock->cll_holds && - lock->cll_holds >= lock->cll_users && - lock->cll_holds >= 0 && - lock->cll_users >= 0 && - lock->cll_depth >= 0; -} - -/** - * Stronger lock invariant, checking that caller has a reference on a lock. - * - * \see cl_lock_invariant_trusted() - */ -static int cl_lock_invariant(const struct lu_env *env, - const struct cl_lock *lock) -{ - int result; - - result = atomic_read(&lock->cll_ref) > 0 && - cl_lock_invariant_trusted(env, lock); - if (!result && env) - CL_LOCK_DEBUG(D_ERROR, env, lock, "invariant broken\n"); - return result; -} - -/** - * Returns lock "nesting": 0 for a top-lock and 1 for a sub-lock. - */ -static enum clt_nesting_level cl_lock_nesting(const struct cl_lock *lock) -{ - return cl_object_header(lock->cll_descr.cld_obj)->coh_nesting; -} - -/** - * Returns a set of counters for this lock, depending on a lock nesting. - */ -static struct cl_thread_counters *cl_lock_counters(const struct lu_env *env, - const struct cl_lock *lock) -{ - struct cl_thread_info *info; - enum clt_nesting_level nesting; - - info = cl_env_info(env); - nesting = cl_lock_nesting(lock); - LASSERT(nesting < ARRAY_SIZE(info->clt_counters)); - return &info->clt_counters[nesting]; -} - static void cl_lock_trace0(int level, const struct lu_env *env, const char *prefix, const struct cl_lock *lock, const char *func, const int line) { struct cl_object_header *h = cl_object_header(lock->cll_descr.cld_obj); - CDEBUG(level, "%s: %p@(%d %p %d %d %d %d %d %lx)(%p/%d/%d) at %s():%d\n", - prefix, lock, atomic_read(&lock->cll_ref), - lock->cll_guarder, lock->cll_depth, - lock->cll_state, lock->cll_error, lock->cll_holds, - lock->cll_users, lock->cll_flags, - env, h->coh_nesting, cl_lock_nr_mutexed(env), - func, line); + CDEBUG(level, "%s: %p (%p/%d) at %s():%d\n", + prefix, lock, env, h->coh_nesting, func, line); } - -#define cl_lock_trace(level, env, prefix, lock) \ +#define cl_lock_trace(level, env, prefix, lock) \ cl_lock_trace0(level, env, prefix, lock, __func__, __LINE__) -#define RETIP ((unsigned long)__builtin_return_address(0)) - -#ifdef CONFIG_LOCKDEP -static struct lock_class_key cl_lock_key; - -static void cl_lock_lockdep_init(struct cl_lock *lock) -{ - lockdep_set_class_and_name(lock, &cl_lock_key, "EXT"); -} - -static void cl_lock_lockdep_acquire(const struct lu_env *env, - struct cl_lock *lock, __u32 enqflags) -{ - cl_lock_counters(env, lock)->ctc_nr_locks_acquired++; - lock_map_acquire(&lock->dep_map); -} - -static void cl_lock_lockdep_release(const struct lu_env *env, - struct cl_lock *lock) -{ - cl_lock_counters(env, lock)->ctc_nr_locks_acquired--; - lock_release(&lock->dep_map, 0, RETIP); -} - -#else /* !CONFIG_LOCKDEP */ - -static void cl_lock_lockdep_init(struct cl_lock *lock) -{} -static void cl_lock_lockdep_acquire(const struct lu_env *env, - struct cl_lock *lock, __u32 enqflags) -{} -static void cl_lock_lockdep_release(const struct lu_env *env, - struct cl_lock *lock) -{} - -#endif /* !CONFIG_LOCKDEP */ - /** * Adds lock slice to the compound lock. * @@ -199,62 +80,10 @@ void cl_lock_slice_add(struct cl_lock *lock, struct cl_lock_slice *slice, } EXPORT_SYMBOL(cl_lock_slice_add); -/** - * Returns true iff a lock with the mode \a has provides at least the same - * guarantees as a lock with the mode \a need. - */ -int cl_lock_mode_match(enum cl_lock_mode has, enum cl_lock_mode need) -{ - LINVRNT(need == CLM_READ || need == CLM_WRITE || - need == CLM_PHANTOM || need == CLM_GROUP); - LINVRNT(has == CLM_READ || has == CLM_WRITE || - has == CLM_PHANTOM || has == CLM_GROUP); - CLASSERT(CLM_PHANTOM < CLM_READ); - CLASSERT(CLM_READ < CLM_WRITE); - CLASSERT(CLM_WRITE < CLM_GROUP); - - if (has != CLM_GROUP) - return need <= has; - else - return need == has; -} -EXPORT_SYMBOL(cl_lock_mode_match); - -/** - * Returns true iff extent portions of lock descriptions match. - */ -int cl_lock_ext_match(const struct cl_lock_descr *has, - const struct cl_lock_descr *need) -{ - return - has->cld_start <= need->cld_start && - has->cld_end >= need->cld_end && - cl_lock_mode_match(has->cld_mode, need->cld_mode) && - (has->cld_mode != CLM_GROUP || has->cld_gid == need->cld_gid); -} -EXPORT_SYMBOL(cl_lock_ext_match); - -/** - * Returns true iff a lock with the description \a has provides at least the - * same guarantees as a lock with the description \a need. - */ -int cl_lock_descr_match(const struct cl_lock_descr *has, - const struct cl_lock_descr *need) +void cl_lock_fini(const struct lu_env *env, struct cl_lock *lock) { - return - cl_object_same(has->cld_obj, need->cld_obj) && - cl_lock_ext_match(has, need); -} -EXPORT_SYMBOL(cl_lock_descr_match); + cl_lock_trace(D_DLMTRACE, env, "destroy lock", lock); -static void cl_lock_free(const struct lu_env *env, struct cl_lock *lock) -{ - struct cl_object *obj = lock->cll_descr.cld_obj; - - LINVRNT(!cl_lock_is_mutexed(lock)); - - cl_lock_trace(D_DLMTRACE, env, "free lock", lock); - might_sleep(); while (!list_empty(&lock->cll_layers)) { struct cl_lock_slice *slice; @@ -263,350 +92,36 @@ static void cl_lock_free(const struct lu_env *env, struct cl_lock *lock) list_del_init(lock->cll_layers.next); slice->cls_ops->clo_fini(env, slice); } - CS_LOCK_DEC(obj, total); - CS_LOCKSTATE_DEC(obj, lock->cll_state); - lu_object_ref_del_at(&obj->co_lu, &lock->cll_obj_ref, "cl_lock", lock); - cl_object_put(env, obj); - lu_ref_fini(&lock->cll_reference); - lu_ref_fini(&lock->cll_holders); - mutex_destroy(&lock->cll_guard); - kmem_cache_free(cl_lock_kmem, lock); -} - -/** - * Releases a reference on a lock. - * - * When last reference is released, lock is returned to the cache, unless it - * is in cl_lock_state::CLS_FREEING state, in which case it is destroyed - * immediately. - * - * \see cl_object_put(), cl_page_put() - */ -void cl_lock_put(const struct lu_env *env, struct cl_lock *lock) -{ - struct cl_object *obj; - - LINVRNT(cl_lock_invariant(env, lock)); - obj = lock->cll_descr.cld_obj; - LINVRNT(obj); - - CDEBUG(D_TRACE, "releasing reference: %d %p %lu\n", - atomic_read(&lock->cll_ref), lock, RETIP); - - if (atomic_dec_and_test(&lock->cll_ref)) { - if (lock->cll_state == CLS_FREEING) { - LASSERT(list_empty(&lock->cll_linkage)); - cl_lock_free(env, lock); - } - CS_LOCK_DEC(obj, busy); - } -} -EXPORT_SYMBOL(cl_lock_put); - -/** - * Acquires an additional reference to a lock. - * - * This can be called only by caller already possessing a reference to \a - * lock. - * - * \see cl_object_get(), cl_page_get() - */ -void cl_lock_get(struct cl_lock *lock) -{ - LINVRNT(cl_lock_invariant(NULL, lock)); - CDEBUG(D_TRACE, "acquiring reference: %d %p %lu\n", - atomic_read(&lock->cll_ref), lock, RETIP); - atomic_inc(&lock->cll_ref); -} -EXPORT_SYMBOL(cl_lock_get); - -/** - * Acquires a reference to a lock. - * - * This is much like cl_lock_get(), except that this function can be used to - * acquire initial reference to the cached lock. Caller has to deal with all - * possible races. Use with care! - * - * \see cl_page_get_trust() - */ -void cl_lock_get_trust(struct cl_lock *lock) -{ - CDEBUG(D_TRACE, "acquiring trusted reference: %d %p %lu\n", - atomic_read(&lock->cll_ref), lock, RETIP); - if (atomic_inc_return(&lock->cll_ref) == 1) - CS_LOCK_INC(lock->cll_descr.cld_obj, busy); -} -EXPORT_SYMBOL(cl_lock_get_trust); - -/** - * Helper function destroying the lock that wasn't completely initialized. - * - * Other threads can acquire references to the top-lock through its - * sub-locks. Hence, it cannot be cl_lock_free()-ed immediately. - */ -static void cl_lock_finish(const struct lu_env *env, struct cl_lock *lock) -{ - cl_lock_mutex_get(env, lock); - cl_lock_cancel(env, lock); - cl_lock_delete(env, lock); - cl_lock_mutex_put(env, lock); - cl_lock_put(env, lock); -} - -static struct cl_lock *cl_lock_alloc(const struct lu_env *env, - struct cl_object *obj, - const struct cl_io *io, - const struct cl_lock_descr *descr) -{ - struct cl_lock *lock; - struct lu_object_header *head; - - lock = kmem_cache_zalloc(cl_lock_kmem, GFP_NOFS); - if (lock) { - atomic_set(&lock->cll_ref, 1); - lock->cll_descr = *descr; - lock->cll_state = CLS_NEW; - cl_object_get(obj); - lu_object_ref_add_at(&obj->co_lu, &lock->cll_obj_ref, "cl_lock", - lock); - INIT_LIST_HEAD(&lock->cll_layers); - INIT_LIST_HEAD(&lock->cll_linkage); - INIT_LIST_HEAD(&lock->cll_inclosure); - lu_ref_init(&lock->cll_reference); - lu_ref_init(&lock->cll_holders); - mutex_init(&lock->cll_guard); - lockdep_set_class(&lock->cll_guard, &cl_lock_guard_class); - init_waitqueue_head(&lock->cll_wq); - head = obj->co_lu.lo_header; - CS_LOCKSTATE_INC(obj, CLS_NEW); - CS_LOCK_INC(obj, total); - CS_LOCK_INC(obj, create); - cl_lock_lockdep_init(lock); - list_for_each_entry(obj, &head->loh_layers, co_lu.lo_linkage) { - int err; - - err = obj->co_ops->coo_lock_init(env, obj, lock, io); - if (err != 0) { - cl_lock_finish(env, lock); - lock = ERR_PTR(err); - break; - } - } - } else - lock = ERR_PTR(-ENOMEM); - return lock; -} - -/** - * Transfer the lock into INTRANSIT state and return the original state. - * - * \pre state: CLS_CACHED, CLS_HELD or CLS_ENQUEUED - * \post state: CLS_INTRANSIT - * \see CLS_INTRANSIT - */ -static enum cl_lock_state cl_lock_intransit(const struct lu_env *env, - struct cl_lock *lock) -{ - enum cl_lock_state state = lock->cll_state; - - LASSERT(cl_lock_is_mutexed(lock)); - LASSERT(state != CLS_INTRANSIT); - LASSERTF(state >= CLS_ENQUEUED && state <= CLS_CACHED, - "Malformed lock state %d.\n", state); - - cl_lock_state_set(env, lock, CLS_INTRANSIT); - lock->cll_intransit_owner = current; - cl_lock_hold_add(env, lock, "intransit", current); - return state; -} - -/** - * Exit the intransit state and restore the lock state to the original state - */ -static void cl_lock_extransit(const struct lu_env *env, struct cl_lock *lock, - enum cl_lock_state state) -{ - LASSERT(cl_lock_is_mutexed(lock)); - LASSERT(lock->cll_state == CLS_INTRANSIT); - LASSERT(state != CLS_INTRANSIT); - LASSERT(lock->cll_intransit_owner == current); - - lock->cll_intransit_owner = NULL; - cl_lock_state_set(env, lock, state); - cl_lock_unhold(env, lock, "intransit", current); -} - -/** - * Checking whether the lock is intransit state - */ -int cl_lock_is_intransit(struct cl_lock *lock) -{ - LASSERT(cl_lock_is_mutexed(lock)); - return lock->cll_state == CLS_INTRANSIT && - lock->cll_intransit_owner != current; -} -EXPORT_SYMBOL(cl_lock_is_intransit); -/** - * Returns true iff lock is "suitable" for given io. E.g., locks acquired by - * truncate and O_APPEND cannot be reused for read/non-append-write, as they - * cover multiple stripes and can trigger cascading timeouts. - */ -static int cl_lock_fits_into(const struct lu_env *env, - const struct cl_lock *lock, - const struct cl_lock_descr *need, - const struct cl_io *io) -{ - const struct cl_lock_slice *slice; - - LINVRNT(cl_lock_invariant_trusted(env, lock)); - list_for_each_entry(slice, &lock->cll_layers, cls_linkage) { - if (slice->cls_ops->clo_fits_into && - !slice->cls_ops->clo_fits_into(env, slice, need, io)) - return 0; - } - return 1; + POISON(lock, 0x5a, sizeof(*lock)); } +EXPORT_SYMBOL(cl_lock_fini); -static struct cl_lock *cl_lock_lookup(const struct lu_env *env, - struct cl_object *obj, - const struct cl_io *io, - const struct cl_lock_descr *need) +int cl_lock_init(const struct lu_env *env, struct cl_lock *lock, + const struct cl_io *io) { - struct cl_lock *lock; - struct cl_object_header *head; - - head = cl_object_header(obj); - assert_spin_locked(&head->coh_lock_guard); - CS_LOCK_INC(obj, lookup); - list_for_each_entry(lock, &head->coh_locks, cll_linkage) { - int matched; - - matched = cl_lock_ext_match(&lock->cll_descr, need) && - lock->cll_state < CLS_FREEING && - lock->cll_error == 0 && - !(lock->cll_flags & CLF_CANCELLED) && - cl_lock_fits_into(env, lock, need, io); - CDEBUG(D_DLMTRACE, "has: "DDESCR"(%d) need: "DDESCR": %d\n", - PDESCR(&lock->cll_descr), lock->cll_state, PDESCR(need), - matched); - if (matched) { - cl_lock_get_trust(lock); - CS_LOCK_INC(obj, hit); - return lock; - } - } - return NULL; -} - -/** - * Returns a lock matching description \a need. - * - * This is the main entry point into the cl_lock caching interface. First, a - * cache (implemented as a per-object linked list) is consulted. If lock is - * found there, it is returned immediately. Otherwise new lock is allocated - * and returned. In any case, additional reference to lock is acquired. - * - * \see cl_object_find(), cl_page_find() - */ -static struct cl_lock *cl_lock_find(const struct lu_env *env, - const struct cl_io *io, - const struct cl_lock_descr *need) -{ - struct cl_object_header *head; - struct cl_object *obj; - struct cl_lock *lock; - - obj = need->cld_obj; - head = cl_object_header(obj); - - spin_lock(&head->coh_lock_guard); - lock = cl_lock_lookup(env, obj, io, need); - spin_unlock(&head->coh_lock_guard); + struct cl_object *obj = lock->cll_descr.cld_obj; + struct cl_object *scan; + int result = 0; - if (!lock) { - lock = cl_lock_alloc(env, obj, io, need); - if (!IS_ERR(lock)) { - struct cl_lock *ghost; + /* Make sure cl_lock::cll_descr is initialized. */ + LASSERT(obj); - spin_lock(&head->coh_lock_guard); - ghost = cl_lock_lookup(env, obj, io, need); - if (!ghost) { - cl_lock_get_trust(lock); - list_add_tail(&lock->cll_linkage, - &head->coh_locks); - spin_unlock(&head->coh_lock_guard); - CS_LOCK_INC(obj, busy); - } else { - spin_unlock(&head->coh_lock_guard); - /* - * Other threads can acquire references to the - * top-lock through its sub-locks. Hence, it - * cannot be cl_lock_free()-ed immediately. - */ - cl_lock_finish(env, lock); - lock = ghost; - } + INIT_LIST_HEAD(&lock->cll_layers); + list_for_each_entry(scan, &obj->co_lu.lo_header->loh_layers, + co_lu.lo_linkage) { + result = scan->co_ops->coo_lock_init(env, scan, lock, io); + if (result != 0) { + cl_lock_fini(env, lock); + break; } } - return lock; -} -/** - * Returns existing lock matching given description. This is similar to - * cl_lock_find() except that no new lock is created, and returned lock is - * guaranteed to be in enum cl_lock_state::CLS_HELD state. - */ -struct cl_lock *cl_lock_peek(const struct lu_env *env, const struct cl_io *io, - const struct cl_lock_descr *need, - const char *scope, const void *source) -{ - struct cl_object_header *head; - struct cl_object *obj; - struct cl_lock *lock; - - obj = need->cld_obj; - head = cl_object_header(obj); - - do { - spin_lock(&head->coh_lock_guard); - lock = cl_lock_lookup(env, obj, io, need); - spin_unlock(&head->coh_lock_guard); - if (!lock) - return NULL; - - cl_lock_mutex_get(env, lock); - if (lock->cll_state == CLS_INTRANSIT) - /* Don't care return value. */ - cl_lock_state_wait(env, lock); - if (lock->cll_state == CLS_FREEING) { - cl_lock_mutex_put(env, lock); - cl_lock_put(env, lock); - lock = NULL; - } - } while (!lock); - - cl_lock_hold_add(env, lock, scope, source); - cl_lock_user_add(env, lock); - if (lock->cll_state == CLS_CACHED) - cl_use_try(env, lock, 1); - if (lock->cll_state == CLS_HELD) { - cl_lock_mutex_put(env, lock); - cl_lock_lockdep_acquire(env, lock, 0); - cl_lock_put(env, lock); - } else { - cl_unuse_try(env, lock); - cl_lock_unhold(env, lock, scope, source); - cl_lock_mutex_put(env, lock); - cl_lock_put(env, lock); - lock = NULL; - } - - return lock; + return result; } -EXPORT_SYMBOL(cl_lock_peek); +EXPORT_SYMBOL(cl_lock_init); /** - * Returns a slice within a lock, corresponding to the given layer in the + * Returns a slice with a lock, corresponding to the given layer in the * device stack. * * \see cl_page_at() @@ -616,8 +131,6 @@ const struct cl_lock_slice *cl_lock_at(const struct cl_lock *lock, { const struct cl_lock_slice *slice; - LINVRNT(cl_lock_invariant_trusted(NULL, lock)); - list_for_each_entry(slice, &lock->cll_layers, cls_linkage) { if (slice->cls_obj->co_lu.lo_dev->ld_type == dtype) return slice; @@ -626,1537 +139,96 @@ const struct cl_lock_slice *cl_lock_at(const struct cl_lock *lock, } EXPORT_SYMBOL(cl_lock_at); -static void cl_lock_mutex_tail(const struct lu_env *env, struct cl_lock *lock) -{ - struct cl_thread_counters *counters; - - counters = cl_lock_counters(env, lock); - lock->cll_depth++; - counters->ctc_nr_locks_locked++; - lu_ref_add(&counters->ctc_locks_locked, "cll_guard", lock); - cl_lock_trace(D_TRACE, env, "got mutex", lock); -} - -/** - * Locks cl_lock object. - * - * This is used to manipulate cl_lock fields, and to serialize state - * transitions in the lock state machine. - * - * \post cl_lock_is_mutexed(lock) - * - * \see cl_lock_mutex_put() - */ -void cl_lock_mutex_get(const struct lu_env *env, struct cl_lock *lock) -{ - LINVRNT(cl_lock_invariant(env, lock)); - - if (lock->cll_guarder == current) { - LINVRNT(cl_lock_is_mutexed(lock)); - LINVRNT(lock->cll_depth > 0); - } else { - struct cl_object_header *hdr; - struct cl_thread_info *info; - int i; - - LINVRNT(lock->cll_guarder != current); - hdr = cl_object_header(lock->cll_descr.cld_obj); - /* - * Check that mutices are taken in the bottom-to-top order. - */ - info = cl_env_info(env); - for (i = 0; i < hdr->coh_nesting; ++i) - LASSERT(info->clt_counters[i].ctc_nr_locks_locked == 0); - mutex_lock_nested(&lock->cll_guard, hdr->coh_nesting); - lock->cll_guarder = current; - LINVRNT(lock->cll_depth == 0); - } - cl_lock_mutex_tail(env, lock); -} -EXPORT_SYMBOL(cl_lock_mutex_get); - -/** - * Try-locks cl_lock object. - * - * \retval 0 \a lock was successfully locked - * - * \retval -EBUSY \a lock cannot be locked right now - * - * \post ergo(result == 0, cl_lock_is_mutexed(lock)) - * - * \see cl_lock_mutex_get() - */ -static int cl_lock_mutex_try(const struct lu_env *env, struct cl_lock *lock) -{ - int result; - - LINVRNT(cl_lock_invariant_trusted(env, lock)); - - result = 0; - if (lock->cll_guarder == current) { - LINVRNT(lock->cll_depth > 0); - cl_lock_mutex_tail(env, lock); - } else if (mutex_trylock(&lock->cll_guard)) { - LINVRNT(lock->cll_depth == 0); - lock->cll_guarder = current; - cl_lock_mutex_tail(env, lock); - } else - result = -EBUSY; - return result; -} - -/** - {* Unlocks cl_lock object. - * - * \pre cl_lock_is_mutexed(lock) - * - * \see cl_lock_mutex_get() - */ -void cl_lock_mutex_put(const struct lu_env *env, struct cl_lock *lock) -{ - struct cl_thread_counters *counters; - - LINVRNT(cl_lock_invariant(env, lock)); - LINVRNT(cl_lock_is_mutexed(lock)); - LINVRNT(lock->cll_guarder == current); - LINVRNT(lock->cll_depth > 0); - - counters = cl_lock_counters(env, lock); - LINVRNT(counters->ctc_nr_locks_locked > 0); - - cl_lock_trace(D_TRACE, env, "put mutex", lock); - lu_ref_del(&counters->ctc_locks_locked, "cll_guard", lock); - counters->ctc_nr_locks_locked--; - if (--lock->cll_depth == 0) { - lock->cll_guarder = NULL; - mutex_unlock(&lock->cll_guard); - } -} -EXPORT_SYMBOL(cl_lock_mutex_put); - -/** - * Returns true iff lock's mutex is owned by the current thread. - */ -int cl_lock_is_mutexed(struct cl_lock *lock) -{ - return lock->cll_guarder == current; -} -EXPORT_SYMBOL(cl_lock_is_mutexed); - -/** - * Returns number of cl_lock mutices held by the current thread (environment). - */ -int cl_lock_nr_mutexed(const struct lu_env *env) -{ - struct cl_thread_info *info; - int i; - int locked; - - /* - * NOTE: if summation across all nesting levels (currently 2) proves - * too expensive, a summary counter can be added to - * struct cl_thread_info. - */ - info = cl_env_info(env); - for (i = 0, locked = 0; i < ARRAY_SIZE(info->clt_counters); ++i) - locked += info->clt_counters[i].ctc_nr_locks_locked; - return locked; -} -EXPORT_SYMBOL(cl_lock_nr_mutexed); - -static void cl_lock_cancel0(const struct lu_env *env, struct cl_lock *lock) -{ - LINVRNT(cl_lock_is_mutexed(lock)); - LINVRNT(cl_lock_invariant(env, lock)); - if (!(lock->cll_flags & CLF_CANCELLED)) { - const struct cl_lock_slice *slice; - - lock->cll_flags |= CLF_CANCELLED; - list_for_each_entry_reverse(slice, &lock->cll_layers, - cls_linkage) { - if (slice->cls_ops->clo_cancel) - slice->cls_ops->clo_cancel(env, slice); - } - } -} - -static void cl_lock_delete0(const struct lu_env *env, struct cl_lock *lock) -{ - struct cl_object_header *head; - const struct cl_lock_slice *slice; - - LINVRNT(cl_lock_is_mutexed(lock)); - LINVRNT(cl_lock_invariant(env, lock)); - - if (lock->cll_state < CLS_FREEING) { - bool in_cache; - - LASSERT(lock->cll_state != CLS_INTRANSIT); - cl_lock_state_set(env, lock, CLS_FREEING); - - head = cl_object_header(lock->cll_descr.cld_obj); - - spin_lock(&head->coh_lock_guard); - in_cache = !list_empty(&lock->cll_linkage); - if (in_cache) - list_del_init(&lock->cll_linkage); - spin_unlock(&head->coh_lock_guard); - - if (in_cache) /* coh_locks cache holds a refcount. */ - cl_lock_put(env, lock); - - /* - * From now on, no new references to this lock can be acquired - * by cl_lock_lookup(). - */ - list_for_each_entry_reverse(slice, &lock->cll_layers, - cls_linkage) { - if (slice->cls_ops->clo_delete) - slice->cls_ops->clo_delete(env, slice); - } - /* - * From now on, no new references to this lock can be acquired - * by layer-specific means (like a pointer from struct - * ldlm_lock in osc, or a pointer from top-lock to sub-lock in - * lov). - * - * Lock will be finally freed in cl_lock_put() when last of - * existing references goes away. - */ - } -} - -/** - * Mod(ifie)s cl_lock::cll_holds counter for a given lock. Also, for a - * top-lock (nesting == 0) accounts for this modification in the per-thread - * debugging counters. Sub-lock holds can be released by a thread different - * from one that acquired it. - */ -static void cl_lock_hold_mod(const struct lu_env *env, struct cl_lock *lock, - int delta) -{ - struct cl_thread_counters *counters; - enum clt_nesting_level nesting; - - lock->cll_holds += delta; - nesting = cl_lock_nesting(lock); - if (nesting == CNL_TOP) { - counters = &cl_env_info(env)->clt_counters[CNL_TOP]; - counters->ctc_nr_held += delta; - LASSERT(counters->ctc_nr_held >= 0); - } -} - -/** - * Mod(ifie)s cl_lock::cll_users counter for a given lock. See - * cl_lock_hold_mod() for the explanation of the debugging code. - */ -static void cl_lock_used_mod(const struct lu_env *env, struct cl_lock *lock, - int delta) -{ - struct cl_thread_counters *counters; - enum clt_nesting_level nesting; - - lock->cll_users += delta; - nesting = cl_lock_nesting(lock); - if (nesting == CNL_TOP) { - counters = &cl_env_info(env)->clt_counters[CNL_TOP]; - counters->ctc_nr_used += delta; - LASSERT(counters->ctc_nr_used >= 0); - } -} - -void cl_lock_hold_release(const struct lu_env *env, struct cl_lock *lock, - const char *scope, const void *source) -{ - LINVRNT(cl_lock_is_mutexed(lock)); - LINVRNT(cl_lock_invariant(env, lock)); - LASSERT(lock->cll_holds > 0); - - cl_lock_trace(D_DLMTRACE, env, "hold release lock", lock); - lu_ref_del(&lock->cll_holders, scope, source); - cl_lock_hold_mod(env, lock, -1); - if (lock->cll_holds == 0) { - CL_LOCK_ASSERT(lock->cll_state != CLS_HELD, env, lock); - if (lock->cll_descr.cld_mode == CLM_PHANTOM || - lock->cll_descr.cld_mode == CLM_GROUP || - lock->cll_state != CLS_CACHED) - /* - * If lock is still phantom or grouplock when user is - * done with it---destroy the lock. - */ - lock->cll_flags |= CLF_CANCELPEND|CLF_DOOMED; - if (lock->cll_flags & CLF_CANCELPEND) { - lock->cll_flags &= ~CLF_CANCELPEND; - cl_lock_cancel0(env, lock); - } - if (lock->cll_flags & CLF_DOOMED) { - /* no longer doomed: it's dead... Jim. */ - lock->cll_flags &= ~CLF_DOOMED; - cl_lock_delete0(env, lock); - } - } -} -EXPORT_SYMBOL(cl_lock_hold_release); - -/** - * Waits until lock state is changed. - * - * This function is called with cl_lock mutex locked, atomically releases - * mutex and goes to sleep, waiting for a lock state change (signaled by - * cl_lock_signal()), and re-acquires the mutex before return. - * - * This function is used to wait until lock state machine makes some progress - * and to emulate synchronous operations on top of asynchronous lock - * interface. - * - * \retval -EINTR wait was interrupted - * - * \retval 0 wait wasn't interrupted - * - * \pre cl_lock_is_mutexed(lock) - * - * \see cl_lock_signal() - */ -int cl_lock_state_wait(const struct lu_env *env, struct cl_lock *lock) -{ - wait_queue_t waiter; - sigset_t blocked; - int result; - - LINVRNT(cl_lock_is_mutexed(lock)); - LINVRNT(cl_lock_invariant(env, lock)); - LASSERT(lock->cll_depth == 1); - LASSERT(lock->cll_state != CLS_FREEING); /* too late to wait */ - - cl_lock_trace(D_DLMTRACE, env, "state wait lock", lock); - result = lock->cll_error; - if (result == 0) { - /* To avoid being interrupted by the 'non-fatal' signals - * (SIGCHLD, for instance), we'd block them temporarily. - * LU-305 - */ - blocked = cfs_block_sigsinv(LUSTRE_FATAL_SIGS); - - init_waitqueue_entry(&waiter, current); - add_wait_queue(&lock->cll_wq, &waiter); - set_current_state(TASK_INTERRUPTIBLE); - cl_lock_mutex_put(env, lock); - - LASSERT(cl_lock_nr_mutexed(env) == 0); - - /* Returning ERESTARTSYS instead of EINTR so syscalls - * can be restarted if signals are pending here - */ - result = -ERESTARTSYS; - if (likely(!OBD_FAIL_CHECK(OBD_FAIL_LOCK_STATE_WAIT_INTR))) { - schedule(); - if (!cfs_signal_pending()) - result = 0; - } - - cl_lock_mutex_get(env, lock); - set_current_state(TASK_RUNNING); - remove_wait_queue(&lock->cll_wq, &waiter); - - /* Restore old blocked signals */ - cfs_restore_sigs(blocked); - } - return result; -} -EXPORT_SYMBOL(cl_lock_state_wait); - -static void cl_lock_state_signal(const struct lu_env *env, struct cl_lock *lock, - enum cl_lock_state state) -{ - const struct cl_lock_slice *slice; - - LINVRNT(cl_lock_is_mutexed(lock)); - LINVRNT(cl_lock_invariant(env, lock)); - - list_for_each_entry(slice, &lock->cll_layers, cls_linkage) - if (slice->cls_ops->clo_state) - slice->cls_ops->clo_state(env, slice, state); - wake_up_all(&lock->cll_wq); -} - -/** - * Notifies waiters that lock state changed. - * - * Wakes up all waiters sleeping in cl_lock_state_wait(), also notifies all - * layers about state change by calling cl_lock_operations::clo_state() - * top-to-bottom. - */ -void cl_lock_signal(const struct lu_env *env, struct cl_lock *lock) -{ - cl_lock_trace(D_DLMTRACE, env, "state signal lock", lock); - cl_lock_state_signal(env, lock, lock->cll_state); -} -EXPORT_SYMBOL(cl_lock_signal); - -/** - * Changes lock state. - * - * This function is invoked to notify layers that lock state changed, possible - * as a result of an asynchronous event such as call-back reception. - * - * \post lock->cll_state == state - * - * \see cl_lock_operations::clo_state() - */ -void cl_lock_state_set(const struct lu_env *env, struct cl_lock *lock, - enum cl_lock_state state) -{ - LASSERT(lock->cll_state <= state || - (lock->cll_state == CLS_CACHED && - (state == CLS_HELD || /* lock found in cache */ - state == CLS_NEW || /* sub-lock canceled */ - state == CLS_INTRANSIT)) || - /* lock is in transit state */ - lock->cll_state == CLS_INTRANSIT); - - if (lock->cll_state != state) { - CS_LOCKSTATE_DEC(lock->cll_descr.cld_obj, lock->cll_state); - CS_LOCKSTATE_INC(lock->cll_descr.cld_obj, state); - - cl_lock_state_signal(env, lock, state); - lock->cll_state = state; - } -} -EXPORT_SYMBOL(cl_lock_state_set); - -static int cl_unuse_try_internal(const struct lu_env *env, struct cl_lock *lock) -{ - const struct cl_lock_slice *slice; - int result; - - do { - result = 0; - - LINVRNT(cl_lock_is_mutexed(lock)); - LINVRNT(cl_lock_invariant(env, lock)); - LASSERT(lock->cll_state == CLS_INTRANSIT); - - result = -ENOSYS; - list_for_each_entry_reverse(slice, &lock->cll_layers, - cls_linkage) { - if (slice->cls_ops->clo_unuse) { - result = slice->cls_ops->clo_unuse(env, slice); - if (result != 0) - break; - } - } - LASSERT(result != -ENOSYS); - } while (result == CLO_REPEAT); - - return result; -} - -/** - * Yanks lock from the cache (cl_lock_state::CLS_CACHED state) by calling - * cl_lock_operations::clo_use() top-to-bottom to notify layers. - * @atomic = 1, it must unuse the lock to recovery the lock to keep the - * use process atomic - */ -int cl_use_try(const struct lu_env *env, struct cl_lock *lock, int atomic) +void cl_lock_cancel(const struct lu_env *env, struct cl_lock *lock) { const struct cl_lock_slice *slice; - int result; - enum cl_lock_state state; - - cl_lock_trace(D_DLMTRACE, env, "use lock", lock); - - LASSERT(lock->cll_state == CLS_CACHED); - if (lock->cll_error) - return lock->cll_error; - - result = -ENOSYS; - state = cl_lock_intransit(env, lock); - list_for_each_entry(slice, &lock->cll_layers, cls_linkage) { - if (slice->cls_ops->clo_use) { - result = slice->cls_ops->clo_use(env, slice); - if (result != 0) - break; - } - } - LASSERT(result != -ENOSYS); - - LASSERTF(lock->cll_state == CLS_INTRANSIT, "Wrong state %d.\n", - lock->cll_state); - - if (result == 0) { - state = CLS_HELD; - } else { - if (result == -ESTALE) { - /* - * ESTALE means sublock being cancelled - * at this time, and set lock state to - * be NEW here and ask the caller to repeat. - */ - state = CLS_NEW; - result = CLO_REPEAT; - } - - /* @atomic means back-off-on-failure. */ - if (atomic) { - int rc; - - rc = cl_unuse_try_internal(env, lock); - /* Vet the results. */ - if (rc < 0 && result > 0) - result = rc; - } + cl_lock_trace(D_DLMTRACE, env, "cancel lock", lock); + list_for_each_entry_reverse(slice, &lock->cll_layers, cls_linkage) { + if (slice->cls_ops->clo_cancel) + slice->cls_ops->clo_cancel(env, slice); } - cl_lock_extransit(env, lock, state); - return result; } -EXPORT_SYMBOL(cl_use_try); +EXPORT_SYMBOL(cl_lock_cancel); /** - * Helper for cl_enqueue_try() that calls ->clo_enqueue() across all layers - * top-to-bottom. + * Enqueue a lock. + * \param anchor: if we need to wait for resources before getting the lock, + * use @anchor for the purpose. + * \retval 0 enqueue successfully + * \retval <0 error code */ -static int cl_enqueue_kick(const struct lu_env *env, - struct cl_lock *lock, - struct cl_io *io, __u32 flags) +int cl_lock_enqueue(const struct lu_env *env, struct cl_io *io, + struct cl_lock *lock, struct cl_sync_io *anchor) { - int result; const struct cl_lock_slice *slice; + int rc = -ENOSYS; - result = -ENOSYS; list_for_each_entry(slice, &lock->cll_layers, cls_linkage) { - if (slice->cls_ops->clo_enqueue) { - result = slice->cls_ops->clo_enqueue(env, - slice, io, flags); - if (result != 0) - break; - } - } - LASSERT(result != -ENOSYS); - return result; -} - -/** - * Tries to enqueue a lock. - * - * This function is called repeatedly by cl_enqueue() until either lock is - * enqueued, or error occurs. This function does not block waiting for - * networking communication to complete. - * - * \post ergo(result == 0, lock->cll_state == CLS_ENQUEUED || - * lock->cll_state == CLS_HELD) - * - * \see cl_enqueue() cl_lock_operations::clo_enqueue() - * \see cl_lock_state::CLS_ENQUEUED - */ -int cl_enqueue_try(const struct lu_env *env, struct cl_lock *lock, - struct cl_io *io, __u32 flags) -{ - int result; - - cl_lock_trace(D_DLMTRACE, env, "enqueue lock", lock); - do { - LINVRNT(cl_lock_is_mutexed(lock)); - - result = lock->cll_error; - if (result != 0) - break; - - switch (lock->cll_state) { - case CLS_NEW: - cl_lock_state_set(env, lock, CLS_QUEUING); - /* fall-through */ - case CLS_QUEUING: - /* kick layers. */ - result = cl_enqueue_kick(env, lock, io, flags); - /* For AGL case, the cl_lock::cll_state may - * become CLS_HELD already. - */ - if (result == 0 && lock->cll_state == CLS_QUEUING) - cl_lock_state_set(env, lock, CLS_ENQUEUED); - break; - case CLS_INTRANSIT: - LASSERT(cl_lock_is_intransit(lock)); - result = CLO_WAIT; - break; - case CLS_CACHED: - /* yank lock from the cache. */ - result = cl_use_try(env, lock, 0); - break; - case CLS_ENQUEUED: - case CLS_HELD: - result = 0; - break; - default: - case CLS_FREEING: - /* - * impossible, only held locks with increased - * ->cll_holds can be enqueued, and they cannot be - * freed. - */ - LBUG(); - } - } while (result == CLO_REPEAT); - return result; -} -EXPORT_SYMBOL(cl_enqueue_try); - -/** - * Cancel the conflicting lock found during previous enqueue. - * - * \retval 0 conflicting lock has been canceled. - * \retval -ve error code. - */ -int cl_lock_enqueue_wait(const struct lu_env *env, - struct cl_lock *lock, - int keep_mutex) -{ - struct cl_lock *conflict; - int rc = 0; - - LASSERT(cl_lock_is_mutexed(lock)); - LASSERT(lock->cll_state == CLS_QUEUING); - LASSERT(lock->cll_conflict); - - conflict = lock->cll_conflict; - lock->cll_conflict = NULL; + if (!slice->cls_ops->clo_enqueue) + continue; - cl_lock_mutex_put(env, lock); - LASSERT(cl_lock_nr_mutexed(env) == 0); - - cl_lock_mutex_get(env, conflict); - cl_lock_trace(D_DLMTRACE, env, "enqueue wait", conflict); - cl_lock_cancel(env, conflict); - cl_lock_delete(env, conflict); - - while (conflict->cll_state != CLS_FREEING) { - rc = cl_lock_state_wait(env, conflict); + rc = slice->cls_ops->clo_enqueue(env, slice, io, anchor); if (rc != 0) break; - } - cl_lock_mutex_put(env, conflict); - lu_ref_del(&conflict->cll_reference, "cancel-wait", lock); - cl_lock_put(env, conflict); - - if (keep_mutex) - cl_lock_mutex_get(env, lock); - - LASSERT(rc <= 0); - return rc; -} -EXPORT_SYMBOL(cl_lock_enqueue_wait); - -static int cl_enqueue_locked(const struct lu_env *env, struct cl_lock *lock, - struct cl_io *io, __u32 enqflags) -{ - int result; - - LINVRNT(cl_lock_is_mutexed(lock)); - LINVRNT(cl_lock_invariant(env, lock)); - LASSERT(lock->cll_holds > 0); - - cl_lock_user_add(env, lock); - do { - result = cl_enqueue_try(env, lock, io, enqflags); - if (result == CLO_WAIT) { - if (lock->cll_conflict) - result = cl_lock_enqueue_wait(env, lock, 1); - else - result = cl_lock_state_wait(env, lock); - if (result == 0) - continue; - } - break; - } while (1); - if (result != 0) - cl_unuse_try(env, lock); - LASSERT(ergo(result == 0 && !(enqflags & CEF_AGL), - lock->cll_state == CLS_ENQUEUED || - lock->cll_state == CLS_HELD)); - return result; -} - -/** - * Tries to unlock a lock. - * - * This function is called to release underlying resource: - * 1. for top lock, the resource is sublocks it held; - * 2. for sublock, the resource is the reference to dlmlock. - * - * cl_unuse_try is a one-shot operation, so it must NOT return CLO_WAIT. - * - * \see cl_unuse() cl_lock_operations::clo_unuse() - * \see cl_lock_state::CLS_CACHED - */ -int cl_unuse_try(const struct lu_env *env, struct cl_lock *lock) -{ - int result; - enum cl_lock_state state = CLS_NEW; - - cl_lock_trace(D_DLMTRACE, env, "unuse lock", lock); - - if (lock->cll_users > 1) { - cl_lock_user_del(env, lock); - return 0; - } - - /* Only if the lock is in CLS_HELD or CLS_ENQUEUED state, it can hold - * underlying resources. - */ - if (!(lock->cll_state == CLS_HELD || lock->cll_state == CLS_ENQUEUED)) { - cl_lock_user_del(env, lock); - return 0; - } - - /* - * New lock users (->cll_users) are not protecting unlocking - * from proceeding. From this point, lock eventually reaches - * CLS_CACHED, is reinitialized to CLS_NEW or fails into - * CLS_FREEING. - */ - state = cl_lock_intransit(env, lock); - - result = cl_unuse_try_internal(env, lock); - LASSERT(lock->cll_state == CLS_INTRANSIT); - LASSERT(result != CLO_WAIT); - cl_lock_user_del(env, lock); - if (result == 0 || result == -ESTALE) { - /* - * Return lock back to the cache. This is the only - * place where lock is moved into CLS_CACHED state. - * - * If one of ->clo_unuse() methods returned -ESTALE, lock - * cannot be placed into cache and has to be - * re-initialized. This happens e.g., when a sub-lock was - * canceled while unlocking was in progress. - */ - if (state == CLS_HELD && result == 0) - state = CLS_CACHED; - else - state = CLS_NEW; - cl_lock_extransit(env, lock, state); - - /* - * Hide -ESTALE error. - * If the lock is a glimpse lock, and it has multiple - * stripes. Assuming that one of its sublock returned -ENAVAIL, - * and other sublocks are matched write locks. In this case, - * we can't set this lock to error because otherwise some of - * its sublocks may not be canceled. This causes some dirty - * pages won't be written to OSTs. -jay - */ - result = 0; - } else { - CERROR("result = %d, this is unlikely!\n", result); - state = CLS_NEW; - cl_lock_extransit(env, lock, state); - } - return result ?: lock->cll_error; -} -EXPORT_SYMBOL(cl_unuse_try); - -static void cl_unuse_locked(const struct lu_env *env, struct cl_lock *lock) -{ - int result; - - result = cl_unuse_try(env, lock); - if (result) - CL_LOCK_DEBUG(D_ERROR, env, lock, "unuse return %d\n", result); -} - -/** - * Unlocks a lock. - */ -void cl_unuse(const struct lu_env *env, struct cl_lock *lock) -{ - cl_lock_mutex_get(env, lock); - cl_unuse_locked(env, lock); - cl_lock_mutex_put(env, lock); - cl_lock_lockdep_release(env, lock); -} -EXPORT_SYMBOL(cl_unuse); - -/** - * Tries to wait for a lock. - * - * This function is called repeatedly by cl_wait() until either lock is - * granted, or error occurs. This function does not block waiting for network - * communication to complete. - * - * \see cl_wait() cl_lock_operations::clo_wait() - * \see cl_lock_state::CLS_HELD - */ -int cl_wait_try(const struct lu_env *env, struct cl_lock *lock) -{ - const struct cl_lock_slice *slice; - int result; - - cl_lock_trace(D_DLMTRACE, env, "wait lock try", lock); - do { - LINVRNT(cl_lock_is_mutexed(lock)); - LINVRNT(cl_lock_invariant(env, lock)); - LASSERTF(lock->cll_state == CLS_QUEUING || - lock->cll_state == CLS_ENQUEUED || - lock->cll_state == CLS_HELD || - lock->cll_state == CLS_INTRANSIT, - "lock state: %d\n", lock->cll_state); - LASSERT(lock->cll_users > 0); - LASSERT(lock->cll_holds > 0); - - result = lock->cll_error; - if (result != 0) - break; - - if (cl_lock_is_intransit(lock)) { - result = CLO_WAIT; - break; - } - - if (lock->cll_state == CLS_HELD) - /* nothing to do */ - break; - - result = -ENOSYS; - list_for_each_entry(slice, &lock->cll_layers, cls_linkage) { - if (slice->cls_ops->clo_wait) { - result = slice->cls_ops->clo_wait(env, slice); - if (result != 0) - break; - } - } - LASSERT(result != -ENOSYS); - if (result == 0) { - LASSERT(lock->cll_state != CLS_INTRANSIT); - cl_lock_state_set(env, lock, CLS_HELD); - } - } while (result == CLO_REPEAT); - return result; -} -EXPORT_SYMBOL(cl_wait_try); - -/** - * Waits until enqueued lock is granted. - * - * \pre current thread or io owns a hold on the lock - * \pre ergo(result == 0, lock->cll_state == CLS_ENQUEUED || - * lock->cll_state == CLS_HELD) - * - * \post ergo(result == 0, lock->cll_state == CLS_HELD) - */ -int cl_wait(const struct lu_env *env, struct cl_lock *lock) -{ - int result; - - cl_lock_mutex_get(env, lock); - - LINVRNT(cl_lock_invariant(env, lock)); - LASSERTF(lock->cll_state == CLS_ENQUEUED || lock->cll_state == CLS_HELD, - "Wrong state %d\n", lock->cll_state); - LASSERT(lock->cll_holds > 0); - - do { - result = cl_wait_try(env, lock); - if (result == CLO_WAIT) { - result = cl_lock_state_wait(env, lock); - if (result == 0) - continue; - } - break; - } while (1); - if (result < 0) { - cl_unuse_try(env, lock); - cl_lock_lockdep_release(env, lock); - } - cl_lock_trace(D_DLMTRACE, env, "wait lock", lock); - cl_lock_mutex_put(env, lock); - LASSERT(ergo(result == 0, lock->cll_state == CLS_HELD)); - return result; -} -EXPORT_SYMBOL(cl_wait); - -/** - * Executes cl_lock_operations::clo_weigh(), and sums results to estimate lock - * value. - */ -unsigned long cl_lock_weigh(const struct lu_env *env, struct cl_lock *lock) -{ - const struct cl_lock_slice *slice; - unsigned long pound; - unsigned long ounce; - - LINVRNT(cl_lock_is_mutexed(lock)); - LINVRNT(cl_lock_invariant(env, lock)); - - pound = 0; - list_for_each_entry_reverse(slice, &lock->cll_layers, cls_linkage) { - if (slice->cls_ops->clo_weigh) { - ounce = slice->cls_ops->clo_weigh(env, slice); - pound += ounce; - if (pound < ounce) /* over-weight^Wflow */ - pound = ~0UL; - } - } - return pound; -} -EXPORT_SYMBOL(cl_lock_weigh); - -/** - * Notifies layers that lock description changed. - * - * The server can grant client a lock different from one that was requested - * (e.g., larger in extent). This method is called when actually granted lock - * description becomes known to let layers to accommodate for changed lock - * description. - * - * \see cl_lock_operations::clo_modify() - */ -int cl_lock_modify(const struct lu_env *env, struct cl_lock *lock, - const struct cl_lock_descr *desc) -{ - const struct cl_lock_slice *slice; - struct cl_object *obj = lock->cll_descr.cld_obj; - struct cl_object_header *hdr = cl_object_header(obj); - int result; - - cl_lock_trace(D_DLMTRACE, env, "modify lock", lock); - /* don't allow object to change */ - LASSERT(obj == desc->cld_obj); - LINVRNT(cl_lock_is_mutexed(lock)); - LINVRNT(cl_lock_invariant(env, lock)); - - list_for_each_entry_reverse(slice, &lock->cll_layers, cls_linkage) { - if (slice->cls_ops->clo_modify) { - result = slice->cls_ops->clo_modify(env, slice, desc); - if (result != 0) - return result; - } - } - CL_LOCK_DEBUG(D_DLMTRACE, env, lock, " -> "DDESCR"@"DFID"\n", - PDESCR(desc), PFID(lu_object_fid(&desc->cld_obj->co_lu))); - /* - * Just replace description in place. Nothing more is needed for - * now. If locks were indexed according to their extent and/or mode, - * that index would have to be updated here. - */ - spin_lock(&hdr->coh_lock_guard); - lock->cll_descr = *desc; - spin_unlock(&hdr->coh_lock_guard); - return 0; -} -EXPORT_SYMBOL(cl_lock_modify); - -/** - * Initializes lock closure with a given origin. - * - * \see cl_lock_closure - */ -void cl_lock_closure_init(const struct lu_env *env, - struct cl_lock_closure *closure, - struct cl_lock *origin, int wait) -{ - LINVRNT(cl_lock_is_mutexed(origin)); - LINVRNT(cl_lock_invariant(env, origin)); - - INIT_LIST_HEAD(&closure->clc_list); - closure->clc_origin = origin; - closure->clc_wait = wait; - closure->clc_nr = 0; -} -EXPORT_SYMBOL(cl_lock_closure_init); - -/** - * Builds a closure of \a lock. - * - * Building of a closure consists of adding initial lock (\a lock) into it, - * and calling cl_lock_operations::clo_closure() methods of \a lock. These - * methods might call cl_lock_closure_build() recursively again, adding more - * locks to the closure, etc. - * - * \see cl_lock_closure - */ -int cl_lock_closure_build(const struct lu_env *env, struct cl_lock *lock, - struct cl_lock_closure *closure) -{ - const struct cl_lock_slice *slice; - int result; - - LINVRNT(cl_lock_is_mutexed(closure->clc_origin)); - LINVRNT(cl_lock_invariant(env, closure->clc_origin)); - - result = cl_lock_enclosure(env, lock, closure); - if (result == 0) { - list_for_each_entry(slice, &lock->cll_layers, cls_linkage) { - if (slice->cls_ops->clo_closure) { - result = slice->cls_ops->clo_closure(env, slice, - closure); - if (result != 0) - break; - } - } - } - if (result != 0) - cl_lock_disclosure(env, closure); - return result; -} -EXPORT_SYMBOL(cl_lock_closure_build); - -/** - * Adds new lock to a closure. - * - * Try-locks \a lock and if succeeded, adds it to the closure (never more than - * once). If try-lock failed, returns CLO_REPEAT, after optionally waiting - * until next try-lock is likely to succeed. - */ -int cl_lock_enclosure(const struct lu_env *env, struct cl_lock *lock, - struct cl_lock_closure *closure) -{ - int result = 0; - - cl_lock_trace(D_DLMTRACE, env, "enclosure lock", lock); - if (!cl_lock_mutex_try(env, lock)) { - /* - * If lock->cll_inclosure is not empty, lock is already in - * this closure. - */ - if (list_empty(&lock->cll_inclosure)) { - cl_lock_get_trust(lock); - lu_ref_add(&lock->cll_reference, "closure", closure); - list_add(&lock->cll_inclosure, &closure->clc_list); - closure->clc_nr++; - } else - cl_lock_mutex_put(env, lock); - result = 0; - } else { - cl_lock_disclosure(env, closure); - if (closure->clc_wait) { - cl_lock_get_trust(lock); - lu_ref_add(&lock->cll_reference, "closure-w", closure); - cl_lock_mutex_put(env, closure->clc_origin); - - LASSERT(cl_lock_nr_mutexed(env) == 0); - cl_lock_mutex_get(env, lock); - cl_lock_mutex_put(env, lock); - - cl_lock_mutex_get(env, closure->clc_origin); - lu_ref_del(&lock->cll_reference, "closure-w", closure); - cl_lock_put(env, lock); - } - result = CLO_REPEAT; - } - return result; -} -EXPORT_SYMBOL(cl_lock_enclosure); - -/** Releases mutices of enclosed locks. */ -void cl_lock_disclosure(const struct lu_env *env, - struct cl_lock_closure *closure) -{ - struct cl_lock *scan; - struct cl_lock *temp; - - cl_lock_trace(D_DLMTRACE, env, "disclosure lock", closure->clc_origin); - list_for_each_entry_safe(scan, temp, &closure->clc_list, - cll_inclosure) { - list_del_init(&scan->cll_inclosure); - cl_lock_mutex_put(env, scan); - lu_ref_del(&scan->cll_reference, "closure", closure); - cl_lock_put(env, scan); - closure->clc_nr--; - } - LASSERT(closure->clc_nr == 0); -} -EXPORT_SYMBOL(cl_lock_disclosure); - -/** Finalizes a closure. */ -void cl_lock_closure_fini(struct cl_lock_closure *closure) -{ - LASSERT(closure->clc_nr == 0); - LASSERT(list_empty(&closure->clc_list)); -} -EXPORT_SYMBOL(cl_lock_closure_fini); - -/** - * Destroys this lock. Notifies layers (bottom-to-top) that lock is being - * destroyed, then destroy the lock. If there are holds on the lock, postpone - * destruction until all holds are released. This is called when a decision is - * made to destroy the lock in the future. E.g., when a blocking AST is - * received on it, or fatal communication error happens. - * - * Caller must have a reference on this lock to prevent a situation, when - * deleted lock lingers in memory for indefinite time, because nobody calls - * cl_lock_put() to finish it. - * - * \pre atomic_read(&lock->cll_ref) > 0 - * \pre ergo(cl_lock_nesting(lock) == CNL_TOP, - * cl_lock_nr_mutexed(env) == 1) - * [i.e., if a top-lock is deleted, mutices of no other locks can be - * held, as deletion of sub-locks might require releasing a top-lock - * mutex] - * - * \see cl_lock_operations::clo_delete() - * \see cl_lock::cll_holds - */ -void cl_lock_delete(const struct lu_env *env, struct cl_lock *lock) -{ - LINVRNT(cl_lock_is_mutexed(lock)); - LINVRNT(cl_lock_invariant(env, lock)); - LASSERT(ergo(cl_lock_nesting(lock) == CNL_TOP, - cl_lock_nr_mutexed(env) == 1)); - - cl_lock_trace(D_DLMTRACE, env, "delete lock", lock); - if (lock->cll_holds == 0) - cl_lock_delete0(env, lock); - else - lock->cll_flags |= CLF_DOOMED; -} -EXPORT_SYMBOL(cl_lock_delete); - -/** - * Mark lock as irrecoverably failed, and mark it for destruction. This - * happens when, e.g., server fails to grant a lock to us, or networking - * time-out happens. - * - * \pre atomic_read(&lock->cll_ref) > 0 - * - * \see clo_lock_delete() - * \see cl_lock::cll_holds - */ -void cl_lock_error(const struct lu_env *env, struct cl_lock *lock, int error) -{ - LINVRNT(cl_lock_is_mutexed(lock)); - LINVRNT(cl_lock_invariant(env, lock)); - - if (lock->cll_error == 0 && error != 0) { - cl_lock_trace(D_DLMTRACE, env, "set lock error", lock); - lock->cll_error = error; - cl_lock_signal(env, lock); - cl_lock_cancel(env, lock); - cl_lock_delete(env, lock); - } -} -EXPORT_SYMBOL(cl_lock_error); - -/** - * Cancels this lock. Notifies layers - * (bottom-to-top) that lock is being cancelled, then destroy the lock. If - * there are holds on the lock, postpone cancellation until - * all holds are released. - * - * Cancellation notification is delivered to layers at most once. - * - * \see cl_lock_operations::clo_cancel() - * \see cl_lock::cll_holds - */ -void cl_lock_cancel(const struct lu_env *env, struct cl_lock *lock) -{ - LINVRNT(cl_lock_is_mutexed(lock)); - LINVRNT(cl_lock_invariant(env, lock)); - - cl_lock_trace(D_DLMTRACE, env, "cancel lock", lock); - if (lock->cll_holds == 0) - cl_lock_cancel0(env, lock); - else - lock->cll_flags |= CLF_CANCELPEND; -} -EXPORT_SYMBOL(cl_lock_cancel); - -/** - * Finds an existing lock covering given index and optionally different from a - * given \a except lock. - */ -struct cl_lock *cl_lock_at_pgoff(const struct lu_env *env, - struct cl_object *obj, pgoff_t index, - struct cl_lock *except, - int pending, int canceld) -{ - struct cl_object_header *head; - struct cl_lock *scan; - struct cl_lock *lock; - struct cl_lock_descr *need; - - head = cl_object_header(obj); - need = &cl_env_info(env)->clt_descr; - lock = NULL; - - need->cld_mode = CLM_READ; /* CLM_READ matches both READ & WRITE, but - * not PHANTOM - */ - need->cld_start = need->cld_end = index; - need->cld_enq_flags = 0; - - spin_lock(&head->coh_lock_guard); - /* It is fine to match any group lock since there could be only one - * with a uniq gid and it conflicts with all other lock modes too - */ - list_for_each_entry(scan, &head->coh_locks, cll_linkage) { - if (scan != except && - (scan->cll_descr.cld_mode == CLM_GROUP || - cl_lock_ext_match(&scan->cll_descr, need)) && - scan->cll_state >= CLS_HELD && - scan->cll_state < CLS_FREEING && - /* - * This check is racy as the lock can be canceled right - * after it is done, but this is fine, because page exists - * already. - */ - (canceld || !(scan->cll_flags & CLF_CANCELLED)) && - (pending || !(scan->cll_flags & CLF_CANCELPEND))) { - /* Don't increase cs_hit here since this - * is just a helper function. - */ - cl_lock_get_trust(scan); - lock = scan; - break; } - } - spin_unlock(&head->coh_lock_guard); - return lock; -} -EXPORT_SYMBOL(cl_lock_at_pgoff); - -/** - * Calculate the page offset at the layer of @lock. - * At the time of this writing, @page is top page and @lock is sub lock. - */ -static pgoff_t pgoff_at_lock(struct cl_page *page, struct cl_lock *lock) -{ - struct lu_device_type *dtype; - const struct cl_page_slice *slice; - - dtype = lock->cll_descr.cld_obj->co_lu.lo_dev->ld_type; - slice = cl_page_at(page, dtype); - return slice->cpl_page->cp_index; + return rc; } +EXPORT_SYMBOL(cl_lock_enqueue); /** - * Check if page @page is covered by an extra lock or discard it. + * Main high-level entry point of cl_lock interface that finds existing or + * enqueues new lock matching given description. */ -static int check_and_discard_cb(const struct lu_env *env, struct cl_io *io, - struct cl_page *page, void *cbdata) +int cl_lock_request(const struct lu_env *env, struct cl_io *io, + struct cl_lock *lock) { - struct cl_thread_info *info = cl_env_info(env); - struct cl_lock *lock = cbdata; - pgoff_t index = pgoff_at_lock(page, lock); + struct cl_sync_io *anchor = NULL; + __u32 enq_flags = lock->cll_descr.cld_enq_flags; + int rc; - if (index >= info->clt_fn_index) { - struct cl_lock *tmp; + rc = cl_lock_init(env, lock, io); + if (rc < 0) + return rc; - /* refresh non-overlapped index */ - tmp = cl_lock_at_pgoff(env, lock->cll_descr.cld_obj, index, - lock, 1, 0); - if (tmp) { - /* Cache the first-non-overlapped index so as to skip - * all pages within [index, clt_fn_index). This - * is safe because if tmp lock is canceled, it will - * discard these pages. - */ - info->clt_fn_index = tmp->cll_descr.cld_end + 1; - if (tmp->cll_descr.cld_end == CL_PAGE_EOF) - info->clt_fn_index = CL_PAGE_EOF; - cl_lock_put(env, tmp); - } else if (cl_page_own(env, io, page) == 0) { - /* discard the page */ - cl_page_unmap(env, io, page); - cl_page_discard(env, io, page); - cl_page_disown(env, io, page); - } else { - LASSERT(page->cp_state == CPS_FREEING); - } + if ((enq_flags & CEF_ASYNC) && !(enq_flags & CEF_AGL)) { + anchor = &cl_env_info(env)->clt_anchor; + cl_sync_io_init(anchor, 1, cl_sync_io_end); } - info->clt_next_index = index + 1; - return CLP_GANG_OKAY; -} + rc = cl_lock_enqueue(env, io, lock, anchor); -static int discard_cb(const struct lu_env *env, struct cl_io *io, - struct cl_page *page, void *cbdata) -{ - struct cl_thread_info *info = cl_env_info(env); - struct cl_lock *lock = cbdata; + if (anchor) { + int rc2; - LASSERT(lock->cll_descr.cld_mode >= CLM_WRITE); - KLASSERT(ergo(page->cp_type == CPT_CACHEABLE, - !PageWriteback(cl_page_vmpage(env, page)))); - KLASSERT(ergo(page->cp_type == CPT_CACHEABLE, - !PageDirty(cl_page_vmpage(env, page)))); - - info->clt_next_index = pgoff_at_lock(page, lock) + 1; - if (cl_page_own(env, io, page) == 0) { - /* discard the page */ - cl_page_unmap(env, io, page); - cl_page_discard(env, io, page); - cl_page_disown(env, io, page); - } else { - LASSERT(page->cp_state == CPS_FREEING); + /* drop the reference count held at initialization time */ + cl_sync_io_note(env, anchor, 0); + rc2 = cl_sync_io_wait(env, anchor, 0); + if (rc2 < 0 && rc == 0) + rc = rc2; } - return CLP_GANG_OKAY; -} + if (rc < 0) + cl_lock_release(env, lock); -/** - * Discard pages protected by the given lock. This function traverses radix - * tree to find all covering pages and discard them. If a page is being covered - * by other locks, it should remain in cache. - * - * If error happens on any step, the process continues anyway (the reasoning - * behind this being that lock cancellation cannot be delayed indefinitely). - */ -int cl_lock_discard_pages(const struct lu_env *env, struct cl_lock *lock) -{ - struct cl_thread_info *info = cl_env_info(env); - struct cl_io *io = &info->clt_io; - struct cl_lock_descr *descr = &lock->cll_descr; - cl_page_gang_cb_t cb; - int res; - int result; - - LINVRNT(cl_lock_invariant(env, lock)); - - io->ci_obj = cl_object_top(descr->cld_obj); - io->ci_ignore_layout = 1; - result = cl_io_init(env, io, CIT_MISC, io->ci_obj); - if (result != 0) - goto out; - - cb = descr->cld_mode == CLM_READ ? check_and_discard_cb : discard_cb; - info->clt_fn_index = info->clt_next_index = descr->cld_start; - do { - res = cl_page_gang_lookup(env, descr->cld_obj, io, - info->clt_next_index, descr->cld_end, - cb, (void *)lock); - if (info->clt_next_index > descr->cld_end) - break; - - if (res == CLP_GANG_RESCHED) - cond_resched(); - } while (res != CLP_GANG_OKAY); -out: - cl_io_fini(env, io); - return result; -} -EXPORT_SYMBOL(cl_lock_discard_pages); - -/** - * Eliminate all locks for a given object. - * - * Caller has to guarantee that no lock is in active use. - * - * \param cancel when this is set, cl_locks_prune() cancels locks before - * destroying. - */ -void cl_locks_prune(const struct lu_env *env, struct cl_object *obj, int cancel) -{ - struct cl_object_header *head; - struct cl_lock *lock; - - head = cl_object_header(obj); - /* - * If locks are destroyed without cancellation, all pages must be - * already destroyed (as otherwise they will be left unprotected). - */ - LASSERT(ergo(!cancel, - !head->coh_tree.rnode && head->coh_pages == 0)); - - spin_lock(&head->coh_lock_guard); - while (!list_empty(&head->coh_locks)) { - lock = container_of(head->coh_locks.next, - struct cl_lock, cll_linkage); - cl_lock_get_trust(lock); - spin_unlock(&head->coh_lock_guard); - lu_ref_add(&lock->cll_reference, "prune", current); - -again: - cl_lock_mutex_get(env, lock); - if (lock->cll_state < CLS_FREEING) { - LASSERT(lock->cll_users <= 1); - if (unlikely(lock->cll_users == 1)) { - struct l_wait_info lwi = { 0 }; - - cl_lock_mutex_put(env, lock); - l_wait_event(lock->cll_wq, - lock->cll_users == 0, - &lwi); - goto again; - } - - if (cancel) - cl_lock_cancel(env, lock); - cl_lock_delete(env, lock); - } - cl_lock_mutex_put(env, lock); - lu_ref_del(&lock->cll_reference, "prune", current); - cl_lock_put(env, lock); - spin_lock(&head->coh_lock_guard); - } - spin_unlock(&head->coh_lock_guard); -} -EXPORT_SYMBOL(cl_locks_prune); - -static struct cl_lock *cl_lock_hold_mutex(const struct lu_env *env, - const struct cl_io *io, - const struct cl_lock_descr *need, - const char *scope, const void *source) -{ - struct cl_lock *lock; - - while (1) { - lock = cl_lock_find(env, io, need); - if (IS_ERR(lock)) - break; - cl_lock_mutex_get(env, lock); - if (lock->cll_state < CLS_FREEING && - !(lock->cll_flags & CLF_CANCELLED)) { - cl_lock_hold_mod(env, lock, 1); - lu_ref_add(&lock->cll_holders, scope, source); - lu_ref_add(&lock->cll_reference, scope, source); - break; - } - cl_lock_mutex_put(env, lock); - cl_lock_put(env, lock); - } - return lock; -} - -/** - * Returns a lock matching \a need description with a reference and a hold on - * it. - * - * This is much like cl_lock_find(), except that cl_lock_hold() additionally - * guarantees that lock is not in the CLS_FREEING state on return. - */ -struct cl_lock *cl_lock_hold(const struct lu_env *env, const struct cl_io *io, - const struct cl_lock_descr *need, - const char *scope, const void *source) -{ - struct cl_lock *lock; - - lock = cl_lock_hold_mutex(env, io, need, scope, source); - if (!IS_ERR(lock)) - cl_lock_mutex_put(env, lock); - return lock; -} -EXPORT_SYMBOL(cl_lock_hold); - -/** - * Main high-level entry point of cl_lock interface that finds existing or - * enqueues new lock matching given description. - */ -struct cl_lock *cl_lock_request(const struct lu_env *env, struct cl_io *io, - const struct cl_lock_descr *need, - const char *scope, const void *source) -{ - struct cl_lock *lock; - int rc; - __u32 enqflags = need->cld_enq_flags; - - do { - lock = cl_lock_hold_mutex(env, io, need, scope, source); - if (IS_ERR(lock)) - break; - - rc = cl_enqueue_locked(env, lock, io, enqflags); - if (rc == 0) { - if (cl_lock_fits_into(env, lock, need, io)) { - if (!(enqflags & CEF_AGL)) { - cl_lock_mutex_put(env, lock); - cl_lock_lockdep_acquire(env, lock, - enqflags); - break; - } - rc = 1; - } - cl_unuse_locked(env, lock); - } - cl_lock_trace(D_DLMTRACE, env, - rc <= 0 ? "enqueue failed" : "agl succeed", lock); - cl_lock_hold_release(env, lock, scope, source); - cl_lock_mutex_put(env, lock); - lu_ref_del(&lock->cll_reference, scope, source); - cl_lock_put(env, lock); - if (rc > 0) { - LASSERT(enqflags & CEF_AGL); - lock = NULL; - } else if (rc != 0) { - lock = ERR_PTR(rc); - } - } while (rc == 0); - return lock; + return rc; } EXPORT_SYMBOL(cl_lock_request); /** - * Adds a hold to a known lock. - */ -void cl_lock_hold_add(const struct lu_env *env, struct cl_lock *lock, - const char *scope, const void *source) -{ - LINVRNT(cl_lock_is_mutexed(lock)); - LINVRNT(cl_lock_invariant(env, lock)); - LASSERT(lock->cll_state != CLS_FREEING); - - cl_lock_hold_mod(env, lock, 1); - cl_lock_get(lock); - lu_ref_add(&lock->cll_holders, scope, source); - lu_ref_add(&lock->cll_reference, scope, source); -} -EXPORT_SYMBOL(cl_lock_hold_add); - -/** - * Releases a hold and a reference on a lock, on which caller acquired a - * mutex. - */ -void cl_lock_unhold(const struct lu_env *env, struct cl_lock *lock, - const char *scope, const void *source) -{ - LINVRNT(cl_lock_invariant(env, lock)); - cl_lock_hold_release(env, lock, scope, source); - lu_ref_del(&lock->cll_reference, scope, source); - cl_lock_put(env, lock); -} -EXPORT_SYMBOL(cl_lock_unhold); - -/** * Releases a hold and a reference on a lock, obtained by cl_lock_hold(). */ -void cl_lock_release(const struct lu_env *env, struct cl_lock *lock, - const char *scope, const void *source) +void cl_lock_release(const struct lu_env *env, struct cl_lock *lock) { - LINVRNT(cl_lock_invariant(env, lock)); cl_lock_trace(D_DLMTRACE, env, "release lock", lock); - cl_lock_mutex_get(env, lock); - cl_lock_hold_release(env, lock, scope, source); - cl_lock_mutex_put(env, lock); - lu_ref_del(&lock->cll_reference, scope, source); - cl_lock_put(env, lock); + cl_lock_cancel(env, lock); + cl_lock_fini(env, lock); } EXPORT_SYMBOL(cl_lock_release); -void cl_lock_user_add(const struct lu_env *env, struct cl_lock *lock) -{ - LINVRNT(cl_lock_is_mutexed(lock)); - LINVRNT(cl_lock_invariant(env, lock)); - - cl_lock_used_mod(env, lock, 1); -} -EXPORT_SYMBOL(cl_lock_user_add); - -void cl_lock_user_del(const struct lu_env *env, struct cl_lock *lock) -{ - LINVRNT(cl_lock_is_mutexed(lock)); - LINVRNT(cl_lock_invariant(env, lock)); - LASSERT(lock->cll_users > 0); - - cl_lock_used_mod(env, lock, -1); - if (lock->cll_users == 0) - wake_up_all(&lock->cll_wq); -} -EXPORT_SYMBOL(cl_lock_user_del); - const char *cl_lock_mode_name(const enum cl_lock_mode mode) { static const char *names[] = { - [CLM_PHANTOM] = "P", [CLM_READ] = "R", [CLM_WRITE] = "W", [CLM_GROUP] = "G" @@ -2189,10 +261,8 @@ void cl_lock_print(const struct lu_env *env, void *cookie, lu_printer_t printer, const struct cl_lock *lock) { const struct cl_lock_slice *slice; - (*printer)(env, cookie, "lock@%p[%d %d %d %d %d %08lx] ", - lock, atomic_read(&lock->cll_ref), - lock->cll_state, lock->cll_error, lock->cll_holds, - lock->cll_users, lock->cll_flags); + + (*printer)(env, cookie, "lock@%p", lock); cl_lock_descr_print(env, cookie, printer, &lock->cll_descr); (*printer)(env, cookie, " {\n"); @@ -2207,13 +277,3 @@ void cl_lock_print(const struct lu_env *env, void *cookie, (*printer)(env, cookie, "} lock@%p\n", lock); } EXPORT_SYMBOL(cl_lock_print); - -int cl_lock_init(void) -{ - return lu_kmem_init(cl_lock_caches); -} - -void cl_lock_fini(void) -{ - lu_kmem_fini(cl_lock_caches); -} |