kvmfornfv -

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Diffstat (limited to 'kernel/fs/ocfs2/ocfs2_fs.h')

-rw-r--r--

1 files changed, 2 insertions, 2 deletions

/* FS-Cache object state machine handler * * Copyright (C) 2007 Red Hat, Inc. All Rights Reserved. * Written by David Howells (dhowells@redhat.com) * * This program is free software; you can redistribute it and/or * modify it under the terms of the GNU General Public License * as published by the Free Software Foundation; either version * 2 of the License, or (at your option) any later version. * * See Documentation/filesystems/caching/object.txt for a description of the * object state machine and the in-kernel representations. */ #define FSCACHE_DEBUG_LEVEL COOKIE #include <linux/module.h> #include <linux/slab.h> #include <linux/prefetch.h> #include "internal.h" static const struct fscache_state *fscache_abort_initialisation(struct fscache_object *, int); static const struct fscache_state *fscache_kill_dependents(struct fscache_object *, int); static const struct fscache_state *fscache_drop_object(struct fscache_object *, int); static const struct fscache_state *fscache_initialise_object(struct fscache_object *, int); static const struct fscache_state *fscache_invalidate_object(struct fscache_object *, int); static const struct fscache_state *fscache_jumpstart_dependents(struct fscache_object *, int); static const struct fscache_state *fscache_kill_object(struct fscache_object *, int); static const struct fscache_state *fscache_lookup_failure(struct fscache_object *, int); static const struct fscache_state *fscache_look_up_object(struct fscache_object *, int); static const struct fscache_state *fscache_object_available(struct fscache_object *, int); static const struct fscache_state *fscache_parent_ready(struct fscache_object *, int); static const struct fscache_state *fscache_update_object(struct fscache_object *, int); #define __STATE_NAME(n) fscache_osm_##n #define STATE(n) (&__STATE_NAME(n)) /* * Define a work state. Work states are execution states. No event processing * is performed by them. The function attached to a work state returns a * pointer indicating the next state to which the state machine should * transition. Returning NO_TRANSIT repeats the current state, but goes back * to the scheduler first. */ #define WORK_STATE(n, sn, f) \ const struct fscache_state __STATE_NAME(n) = { \ .name = #n, \ .short_name = sn, \ .work = f \ } /* * Returns from work states. */ #define transit_to(state) ({ prefetch(&STATE(state)->work); STATE(state); }) #define NO_TRANSIT ((struct fscache_state *)NULL) /* * Define a wait state. Wait states are event processing states. No execution * is performed by them. Wait states are just tables of "if event X occurs, * clear it and transition to state Y". The dispatcher returns to the * scheduler if none of the events in which the wait state has an interest are * currently pending. */ #define WAIT_STATE(n, sn, ...) \ const struct fscache_state __STATE_NAME(n) = { \ .name = #n, \ .short_name = sn, \ .work = NULL, \ .transitions = { __VA_ARGS__, { 0, NULL } } \ } #define TRANSIT_TO(state, emask) \ { .events = (emask), .transit_to = STATE(state) } /* * The object state machine. */ static WORK_STATE(INIT_OBJECT, "INIT", fscache_initialise_object); static WORK_STATE(PARENT_READY, "PRDY", fscache_parent_ready); static WORK_STATE(ABORT_INIT, "ABRT", fscache_abort_initialisation); static WORK_STATE(LOOK_UP_OBJECT, "LOOK", fscache_look_up_object); static WORK_STATE(CREATE_OBJECT, "CRTO", fscache_look_up_object); static WORK_STATE(OBJECT_AVAILABLE, "AVBL", fscache_object_available); static WORK_STATE(JUMPSTART_DEPS, "JUMP", fscache_jumpstart_dependents); static WORK_STATE(INVALIDATE_OBJECT, "INVL", fscache_invalidate_object); static WORK_STATE(UPDATE_OBJECT, "UPDT", fscache_update_object); static WORK_STATE(LOOKUP_FAILURE, "LCFL", fscache_lookup_failure); static WORK_STATE(KILL_OBJECT, "KILL", fscache_kill_object); static WORK_STATE(KILL_DEPENDENTS, "KDEP", fscache_kill_dependents); static WORK_STATE(DROP_OBJECT, "DROP", fscache_drop_object); static WORK_STATE(OBJECT_DEAD, "DEAD", (void*)2UL); static WAIT_STATE(WAIT_FOR_INIT, "?INI", TRANSIT_TO(INIT_OBJECT, 1 << FSCACHE_OBJECT_EV_NEW_CHILD)); static WAIT_STATE(WAIT_FOR_PARENT, "?PRN", TRANSIT_TO(PARENT_READY, 1 << FSCACHE_OBJECT_EV_PARENT_READY)); static WAIT_STATE(WAIT_FOR_CMD, "?CMD", TRANSIT_TO(INVALIDATE_OBJECT, 1 << FSCACHE_OBJECT_EV_INVALIDATE), TRANSIT_TO(UPDATE_OBJECT, 1 << FSCACHE_OBJECT_EV_UPDATE), TRANSIT_TO(JUMPSTART_DEPS, 1 << FSCACHE_OBJECT_EV_NEW_CHILD)); static WAIT_STATE(WAIT_FOR_CLEARANCE, "?CLR", TRANSIT_TO(KILL_OBJECT, 1 << FSCACHE_OBJECT_EV_CLEARED)); /* * Out-of-band event transition tables. These are for handling unexpected * events, such as an I/O error. If an OOB event occurs, the state machine * clears and disables the event and forces a transition to the nominated work * state (acurrently executing work states will complete first). * * In such a situation, object->state remembers the state the machine should * have been in/gone to and returning NO_TRANSIT returns to that. */ static const struct fscache_transition fscache_osm_init_oob[] = { TRANSIT_TO(ABORT_INIT, (1 << FSCACHE_OBJECT_EV_ERROR) | (1 << FSCACHE_OBJECT_EV_KILL)), { 0, NULL } }; static const struct fscache_transition fscache_osm_lookup_oob[] = { TRANSIT_TO(LOOKUP_FAILURE, (1 << FSCACHE_OBJECT_EV_ERROR) | (1 << FSCACHE_OBJECT_EV_KILL)), { 0, NULL } }; static const struct fscache_transition fscache_osm_run_oob[] = { TRANSIT_TO(KILL_OBJECT, (1 << FSCACHE_OBJECT_EV_ERROR) | (1 << FSCACHE_OBJECT_EV_KILL)), { 0, NULL } }; static int fscache_get_object(struct fscache_object *); static void fscache_put_object(struct fscache_object *); static bool fscache_enqueue_dependents(struct fscache_object *, int); static void fscache_dequeue_object(struct fscache_object *); /* * we need to notify the parent when an op completes that we had outstanding * upon it */ static inline void fscache_done_parent_op(struct fscache_object *object) { struct fscache_object *parent = object->parent; _enter("OBJ%x {OBJ%x,%x}", object->debug_id, parent->debug_id, parent->n_ops); spin_lock_nested(&parent->lock, 1); parent->n_obj_ops--; parent->n_ops--; if (parent->n_ops == 0) fscache_raise_event(parent, FSCACHE_OBJECT_EV_CLEARED); spin_unlock(&parent->lock); } /* * Object state machine dispatcher. */ static void fscache_object_sm_dispatcher(struct fscache_object *object) { const struct fscache_transition *t; const struct fscache_state *state, *new_state; unsigned long events, event_mask; int event = -1; ASSERT(object != NULL); _enter("{OBJ%x,%s,%lx}", object->debug_id, object->state->name, object->events); event_mask = object->event_mask; restart: object->event_mask = 0; /* Mask normal event handling */ state = object->state; restart_masked: events = object->events; /* Handle any out-of-band events (typically an error) */ if (events & object->oob_event_mask) { _debug("{OBJ%x} oob %lx", object->debug_id, events & object->oob_event_mask); for (t = object->oob_table; t->events; t++) { if (events & t->events) { state = t->transit_to; ASSERT(state->work != NULL); event = fls(events & t->events) - 1; __clear_bit(event, &object->oob_event_mask); clear_bit(event, &object->events); goto execute_work_state; } } } /* Wait states are just transition tables */ if (!state->work) { if (events & event_mask) { for (t = state->transitions; t->events; t++) { if (events & t->events) { new_state = t->transit_to; event = fls(events & t->events) - 1; clear_bit(event, &object->events); _debug("{OBJ%x} ev %d: %s -> %s", object->debug_id, event, state->name, new_state->name); object->state = state = new_state; goto execute_work_state; } } /* The event mask didn't include all the tabled bits */ BUG(); } /* Randomly woke up */ goto unmask_events; } execute_work_state: _debug("{OBJ%x} exec %s", object->debug_id, state->name); new_state = state->work(object, event); event = -1; if (new_state == NO_TRANSIT) { _debug("{OBJ%x} %s notrans", object->debug_id, state->name); fscache_enqueue_object(object); event_mask = object->oob_event_mask; goto unmask_events; } _debug("{OBJ%x} %s -> %s", object->debug_id, state->name, new_state->name); object->state = state = new_state; if (state->work) { if (unlikely(state->work == ((void *)2UL))) { _leave(" [dead]"); return; } goto restart_masked; } /* Transited to wait state */ event_mask = object->oob_event_mask; for (t = state->transitions; t->events; t++) event_mask |= t->events; unmask_events: object->event_mask = event_mask; smp_mb(); events = object->events; if (events & event_mask) goto restart; _leave(" [msk %lx]", event_mask); } /* * execute an object */ static void fscache_object_work_func(struct work_struct *work) { struct fscache_object *object = container_of(work, struct fscache_object, work); unsigned long start; _enter("{OBJ%x}", object->debug_id); start = jiffies; fscache_object_sm_dispatcher(object); fscache_hist(fscache_objs_histogram, start); fscache_put_object(object); } /** * fscache_object_init - Initialise a cache object description * @object: Object description * @cookie: Cookie object will be attached to * @cache: Cache in which backing object will be found * * Initialise a cache object description to its basic values. * * See Documentation/filesystems/caching/backend-api.txt for a complete * description. */ void fscache_object_init(struct fscache_object *object, struct fscache_cookie *cookie, struct fscache_cache *cache) { const struct fscache_transition *t; atomic_inc(&cache->object_count); object->state = STATE(WAIT_FOR_INIT); object->oob_table = fscache_osm_init_oob; object->flags = 1 << FSCACHE_OBJECT_IS_LIVE; spin_lock_init(&object->lock); INIT_LIST_HEAD(&object->cache_link); INIT_HLIST_NODE(&object->cookie_link); INIT_WORK(&object->work, fscache_object_work_func); INIT_LIST_HEAD(&object->dependents); INIT_LIST_HEAD(&object->dep_link); INIT_LIST_HEAD(&object->pending_ops); object->n_children = 0; object->n_ops = object->n_in_progress = object->n_exclusive = 0; object->events = 0; object->store_limit = 0; object->store_limit_l = 0; object->cache = cache; object->cookie = cookie; object->parent = NULL; #ifdef CONFIG_FSCACHE_OBJECT_LIST RB_CLEAR_NODE(&object->objlist_link); #endif object->oob_event_mask = 0; for (t = object->oob_table; t->events; t++) object->oob_event_mask |= t->events; object->event_mask = object->oob_event_mask; for (t = object->state->transitions; t->events; t++) object->event_mask |= t->events; } EXPORT_SYMBOL(fscache_object_init); /* * Mark the object as no longer being live, making sure that we synchronise * against op submission. */ static inline void fscache_mark_object_dead(struct fscache_object *object) { spin_lock(&object->lock); clear_bit(FSCACHE_OBJECT_IS_LIVE, &object->flags); spin_unlock(&object->lock); } /* * Abort object initialisation before we start it. */ static const struct fscache_state *fscache_abort_initialisation(struct fscache_object *object, int event) { _enter("{OBJ%x},%d", object->debug_id, event); object->oob_event_mask = 0; fscache_dequeue_object(object); return transit_to(KILL_OBJECT); } /* * initialise an object * - check the specified object's parent to see if we can make use of it * immediately to do a creation * - we may need to start the process of creating a parent and we need to wait * for the parent's lookup and creation to complete if it's not there yet */ static const struct fscache_state *fscache_initialise_object(struct fscache_object *object, int event) { struct fscache_object *parent; bool success; _enter("{OBJ%x},%d", object->debug_id, event); ASSERT(list_empty(&object->dep_link)); parent = object->parent; if (!parent) { _leave(" [no parent]"); return transit_to(DROP_OBJECT); } _debug("parent: %s of:%lx", parent->state->name, parent->flags); if (fscache_object_is_dying(parent)) { _leave(" [bad parent]"); return transit_to(DROP_OBJECT); } if (fscache_object_is_available(parent)) { _leave(" [ready]"); return transit_to(PARENT_READY); } _debug("wait"); spin_lock(&parent->lock); fscache_stat(&fscache_n_cop_grab_object); success = false; if (fscache_object_is_live(parent) && object->cache->ops->grab_object(object)) { list_add(&object->dep_link, &parent->dependents); success = true; } fscache_stat_d(&fscache_n_cop_grab_object); spin_unlock(&parent->lock); if (!success) { _leave(" [grab failed]"); return transit_to(DROP_OBJECT); } /* fscache_acquire_non_index_cookie() uses this * to wake the chain up */ fscache_raise_event(parent, FSCACHE_OBJECT_EV_NEW_CHILD); _leave(" [wait]"); return transit_to(WAIT_FOR_PARENT); } /* * Once the parent object is ready, we should kick off our lookup op. */ static const struct fscache_state *fscache_parent_ready(struct fscache_object *object, int event) { struct fscache_object *parent = object->parent; _enter("{OBJ%x},%d", object->debug_id, event); ASSERT(parent != NULL); spin_lock(&parent->lock); parent->n_ops++; parent->n_obj_ops++; object->lookup_jif = jiffies; spin_unlock(&parent->lock); _leave(""); return transit_to(LOOK_UP_OBJECT); } /* * look an object up in the cache from which it was allocated * - we hold an "access lock" on the parent object, so the parent object cannot * be withdrawn by either party till we've finished */ static const struct fscache_state *fscache_look_up_object(struct fscache_object *object, int event) { struct fscache_cookie *cookie = object->cookie; struct fscache_object *parent = object->parent; int ret; _enter("{OBJ%x},%d", object->debug_id, event); object->oob_table = fscache_osm_lookup_oob; ASSERT(parent != NULL); ASSERTCMP(parent->n_ops, >, 0); ASSERTCMP(parent->n_obj_ops, >, 0); /* make sure the parent is still available */ ASSERT(fscache_object_is_available(parent)); if (fscache_object_is_dying(parent) || test_bit(FSCACHE_IOERROR, &object->cache->flags) || !fscache_use_cookie(object)) { _leave(" [unavailable]"); return transit_to(LOOKUP_FAILURE); } _debug("LOOKUP \"%s\" in \"%s\"", cookie->def->name, object->cache->tag->name); fscache_stat(&fscache_n_object_lookups); fscache_stat(&fscache_n_cop_lookup_object); ret = object->cache->ops->lookup_object(object); fscache_stat_d(&fscache_n_cop_lookup_object); fscache_unuse_cookie(object); if (ret == -ETIMEDOUT) { /* probably stuck behind another object, so move this one to * the back of the queue */ fscache_stat(&fscache_n_object_lookups_timed_out); _leave(" [timeout]"); return NO_TRANSIT; } if (ret < 0) { _leave(" [error]"); return transit_to(LOOKUP_FAILURE); } _leave(" [ok]"); return transit_to(OBJECT_AVAILABLE); } /** * fscache_object_lookup_negative - Note negative cookie lookup * @object: Object pointing to cookie to mark * * Note negative lookup, permitting those waiting to read data from an already * existing backing object to continue as there's no data for them to read. */ void fscache_object_lookup_negative(struct fscache_object *object) { struct fscache_cookie *cookie = object->cookie; _enter("{OBJ%x,%s}", object->debug_id, object->state->name); if (!test_and_set_bit(FSCACHE_OBJECT_IS_LOOKED_UP, &object->flags)) { fscache_stat(&fscache_n_object_lookups_negative); /* Allow write requests to begin stacking up and read requests to begin * returning ENODATA. */ set_bit(FSCACHE_COOKIE_NO_DATA_YET, &cookie->flags); clear_bit(FSCACHE_COOKIE_UNAVAILABLE, &cookie->flags); _debug("wake up lookup %p", &cookie->flags); clear_bit_unlock(FSCACHE_COOKIE_LOOKING_UP, &cookie->flags); wake_up_bit(&cookie->flags, FSCACHE_COOKIE_LOOKING_UP); } _leave(""); } EXPORT_SYMBOL(fscache_object_lookup_negative); /** * fscache_obtained_object - Note successful object lookup or creation * @object: Object pointing to cookie to mark * * Note successful lookup and/or creation, permitting those waiting to write * data to a backing object to continue. * * Note that after calling this, an object's cookie may be relinquished by the * netfs, and so must be accessed with object lock held. */ void fscache_obtained_object(struct fscache_object *object) { struct fscache_cookie *cookie = object->cookie; _enter("{OBJ%x,%s}", object->debug_id, object->state->name); /* if we were still looking up, then we must have a positive lookup * result, in which case there may be data available */ if (!test_and_set_bit(FSCACHE_OBJECT_IS_LOOKED_UP, &object->flags)) { fscache_stat(&fscache_n_object_lookups_positive); /* We do (presumably) have data */ clear_bit_unlock(FSCACHE_COOKIE_NO_DATA_YET, &cookie->flags); clear_bit(FSCACHE_COOKIE_UNAVAILABLE, &cookie->flags); /* Allow write requests to begin stacking up and read requests * to begin shovelling data. */ clear_bit_unlock(FSCACHE_COOKIE_LOOKING_UP, &cookie->flags); wake_up_bit(&cookie->flags, FSCACHE_COOKIE_LOOKING_UP); } else { fscache_stat(&fscache_n_object_created); } set_bit(FSCACHE_OBJECT_IS_AVAILABLE, &object->flags); _leave(""); } EXPORT_SYMBOL(fscache_obtained_object); /* * handle an object that has just become available */ static const struct fscache_state *fscache_object_available(struct fscache_object *object, int event) { _enter("{OBJ%x},%d", object->debug_id, event); object->oob_table = fscache_osm_run_oob; spin_lock(&object->lock); fscache_done_parent_op(object); if (object->n_in_progress == 0) { if (object->n_ops > 0) { ASSERTCMP(object->n_ops, >=, object->n_obj_ops); fscache_start_operations(object); } else { ASSERT(list_empty(&object->pending_ops)); } } spin_unlock(&object->lock); fscache_stat(&fscache_n_cop_lookup_complete); object->cache->ops->lookup_complete(object); fscache_stat_d(&fscache_n_cop_lookup_complete); fscache_hist(fscache_obj_instantiate_histogram, object->lookup_jif); fscache_stat(&fscache_n_object_avail); _leave(""); return transit_to(JUMPSTART_DEPS); } /* * Wake up this object's dependent objects now that we've become available. */ static const struct fscache_state *fscache_jumpstart_dependents(struct fscache_object *object, int event) { _enter("{OBJ%x},%d", object->debug_id, event); if (!fscache_enqueue_dependents(object, FSCACHE_OBJECT_EV_PARENT_READY)) return NO_TRANSIT; /* Not finished; requeue */ return transit_to(WAIT_FOR_CMD); } /* * Handle lookup or creation failute. */ static const struct fscache_state *fscache_lookup_failure(struct fscache_object *object, int event) { struct fscache_cookie *cookie; _enter("{OBJ%x},%d", object->debug_id, event); object->oob_event_mask = 0; fscache_stat(&fscache_n_cop_lookup_complete); object->cache->ops->lookup_complete(object); fscache_stat_d(&fscache_n_cop_lookup_complete); set_bit(FSCACHE_OBJECT_KILLED_BY_CACHE, &object->flags); cookie = object->cookie; set_bit(FSCACHE_COOKIE_UNAVAILABLE, &cookie->flags); if (test_and_clear_bit(FSCACHE_COOKIE_LOOKING_UP, &cookie->flags)) wake_up_bit(&cookie->flags, FSCACHE_COOKIE_LOOKING_UP); fscache_done_parent_op(object); return transit_to(KILL_OBJECT); } /* * Wait for completion of all active operations on this object and the death of * all child objects of this object. */ static const struct fscache_state *fscache_kill_object(struct fscache_object *object, int event) { _enter("{OBJ%x,%d,%d},%d", object->debug_id, object->n_ops, object->n_children, event); fscache_mark_object_dead(object); object->oob_event_mask = 0; if (list_empty(&object->dependents) && object->n_ops == 0 && object->n_children == 0) return transit_to(DROP_OBJECT); if (object->n_in_progress == 0) { spin_lock(&object->lock); if (object->n_ops > 0 && object->n_in_progress == 0) fscache_start_operations(object); spin_unlock(&object->lock); } if (!list_empty(&object->dependents)) return transit_to(KILL_DEPENDENTS); return transit_to(WAIT_FOR_CLEARANCE); } /* * Kill dependent objects. */ static const struct fscache_state *fscache_kill_dependents(struct fscache_object *object, int event) { _enter("{OBJ%x},%d", object->debug_id, event); if (!fscache_enqueue_dependents(object, FSCACHE_OBJECT_EV_KILL)) return NO_TRANSIT; /* Not finished */ return transit_to(WAIT_FOR_CLEARANCE); } /* * Drop an object's attachments */ static const struct fscache_state *fscache_drop_object(struct fscache_object *object, int event) { struct fscache_object *parent = object->parent; struct fscache_cookie *cookie = object->cookie; struct fscache_cache *cache = object->cache; bool awaken = false; _enter("{OBJ%x,%d},%d", object->debug_id, object->n_children, event); ASSERT(cookie != NULL); ASSERT(!hlist_unhashed(&object->cookie_link)); /* Make sure the cookie no longer points here and that the netfs isn't * waiting for us. */ spin_lock(&cookie->lock); hlist_del_init(&object->cookie_link); if (hlist_empty(&cookie->backing_objects) && test_and_clear_bit(FSCACHE_COOKIE_INVALIDATING, &cookie->flags)) awaken = true; spin_unlock(&cookie->lock); if (awaken) wake_up_bit(&cookie->flags, FSCACHE_COOKIE_INVALIDATING); /* Prevent a race with our last child, which has to signal EV_CLEARED * before dropping our spinlock. */ spin_lock(&object->lock); spin_unlock(&object->lock); /* Discard from the cache's collection of objects */ spin_lock(&cache->object_list_lock); list_del_init(&object->cache_link); spin_unlock(&cache->object_list_lock); fscache_stat(&fscache_n_cop_drop_object); cache->ops->drop_object(object); fscache_stat_d(&fscache_n_cop_drop_object); /* The parent object wants to know when all it dependents have gone */ if (parent) { _debug("release parent OBJ%x {%d}", parent->debug_id, parent->n_children); spin_lock(&parent->lock); parent->n_children--; if (parent->n_children == 0) fscache_raise_event(parent, FSCACHE_OBJECT_EV_CLEARED); spin_unlock(&parent->lock); object->parent = NULL; } /* this just shifts the object release to the work processor */ fscache_put_object(object); fscache_stat(&fscache_n_object_dead); _leave(""); return transit_to(OBJECT_DEAD); } /* * get a ref on an object */ static int fscache_get_object(struct fscache_object *object) { int ret; fscache_stat(&fscache_n_cop_grab_object); ret = object->cache->ops->grab_object(object) ? 0 : -EAGAIN; fscache_stat_d(&fscache_n_cop_grab_object); return ret; } /* * Discard a ref on an object */ static void fscache_put_object(struct fscache_object *object) { fscache_stat(&fscache_n_cop_put_object); object->cache->ops->put_object(object); fscache_stat_d(&fscache_n_cop_put_object); } /** * fscache_object_destroy - Note that a cache object is about to be destroyed * @object: The object to be destroyed * * Note the imminent destruction and deallocation of a cache object record. */ void fscache_object_destroy(struct fscache_object *object) { fscache_objlist_remove(object); /* We can get rid of the cookie now */ fscache_cookie_put(object->cookie); object->cookie = NULL; } EXPORT_SYMBOL(fscache_object_destroy); /* * enqueue an object for metadata-type processing */ void fscache_enqueue_object(struct fscache_object *object) { _enter("{OBJ%x}", object->debug_id); if (fscache_get_object(object) >= 0) { wait_queue_head_t *cong_wq = &get_cpu_var(fscache_object_cong_wait); if (queue_work(fscache_object_wq, &object->work)) { if (fscache_object_congested()) wake_up(cong_wq); } else fscache_put_object(object); put_cpu_var(fscache_object_cong_wait); } } /** * fscache_object_sleep_till_congested - Sleep until object wq is congested * @timeoutp: Scheduler sleep timeout * * Allow an object handler to sleep until the object workqueue is congested. * * The caller must set up a wake up event before calling this and must have set * the appropriate sleep mode (such as TASK_UNINTERRUPTIBLE) and tested its own * condition before calling this function as no test is made here. * * %true is returned if the object wq is congested, %false otherwise. */ bool fscache_object_sleep_till_congested(signed long *timeoutp) { wait_queue_head_t *cong_wq = this_cpu_ptr(&fscache_object_cong_wait); DEFINE_WAIT(wait); if (fscache_object_congested()) return true; add_wait_queue_exclusive(cong_wq, &wait); if (!fscache_object_congested()) *timeoutp = schedule_timeout(*timeoutp); finish_wait(cong_wq, &wait); return fscache_object_congested(); } EXPORT_SYMBOL_GPL(fscache_object_sleep_till_congested); /* * Enqueue the dependents of an object for metadata-type processing. * * If we don't manage to finish the list before the scheduler wants to run * again then return false immediately. We return true if the list was * cleared. */ static bool fscache_enqueue_dependents(struct fscache_object *object, int event) { struct fscache_object *dep; bool ret = true; _enter("{OBJ%x}", object->debug_id); if (list_empty(&object->dependents)) return true; spin_lock(&object->lock); while (!list_empty(&object->dependents)) { dep = list_entry(object->dependents.next, struct fscache_object, dep_link); list_del_init(&dep->dep_link); fscache_raise_event(dep, event); fscache_put_object(dep); if (!list_empty(&object->dependents) && need_resched()) { ret = false; break; } } spin_unlock(&object->lock); return ret; } /* * remove an object from whatever queue it's waiting on */ static void fscache_dequeue_object(struct fscache_object *object) { _enter("{OBJ%x}", object->debug_id); if (!list_empty(&object->dep_link)) { spin_lock(&object->parent->lock); list_del_init(&object->dep_link); spin_unlock(&object->parent->lock); } _leave(""); } /** * fscache_check_aux - Ask the netfs whether an object on disk is still valid * @object: The object to ask about * @data: The auxiliary data for the object * @datalen: The size of the auxiliary data * * This function consults the netfs about the coherency state of an object. * The caller must be holding a ref on cookie->n_active (held by * fscache_look_up_object() on behalf of the cache backend during object lookup * and creation). */ enum fscache_checkaux fscache_check_aux(struct fscache_object *object, const void *data, uint16_t datalen) { enum fscache_checkaux result; if (!object->cookie->def->check_aux) { fscache_stat(&fscache_n_checkaux_none); return FSCACHE_CHECKAUX_OKAY; } result = object->cookie->def->check_aux(object->cookie->netfs_data, data, datalen); switch (result) { /* entry okay as is */ case FSCACHE_CHECKAUX_OKAY: fscache_stat(&fscache_n_checkaux_okay); break; /* entry requires update */ case FSCACHE_CHECKAUX_NEEDS_UPDATE: fscache_stat(&fscache_n_checkaux_update); break; /* entry requires deletion */ case FSCACHE_CHECKAUX_OBSOLETE: fscache_stat(&fscache_n_checkaux_obsolete); break; default: BUG(); } return result; } EXPORT_SYMBOL(fscache_check_aux); /* * Asynchronously invalidate an object. */ static const struct fscache_state *_fscache_invalidate_object(struct fscache_object *object, int event) { struct fscache_operation *op; struct fscache_cookie *cookie = object->cookie; _enter("{OBJ%x},%d", object->debug_id, event); /* We're going to need the cookie. If the cookie is not available then * retire the object instead. */ if (!fscache_use_cookie(object)) { ASSERT(object->cookie->stores.rnode == NULL); set_bit(FSCACHE_OBJECT_RETIRED, &object->flags); _leave(" [no cookie]"); return transit_to(KILL_OBJECT); } /* Reject any new read/write ops and abort any that are pending. */ fscache_invalidate_writes(cookie); clear_bit(FSCACHE_OBJECT_PENDING_WRITE, &object->flags); fscache_cancel_all_ops(object); /* Now we have to wait for in-progress reads and writes */ op = kzalloc(sizeof(*op), GFP_KERNEL); if (!op) goto nomem; fscache_operation_init(op, object->cache->ops->invalidate_object, NULL, NULL); op->flags = FSCACHE_OP_ASYNC | (1 << FSCACHE_OP_EXCLUSIVE) | (1 << FSCACHE_OP_UNUSE_COOKIE); spin_lock(&cookie->lock); if (fscache_submit_exclusive_op(object, op) < 0) goto submit_op_failed; spin_unlock(&cookie->lock); fscache_put_operation(op); /* Once we've completed the invalidation, we know there will be no data * stored in the cache and thus we can reinstate the data-check-skip * optimisation. */ set_bit(FSCACHE_COOKIE_NO_DATA_YET, &cookie->flags); /* We can allow read and write requests to come in once again. They'll * queue up behind our exclusive invalidation operation. */ if (test_and_clear_bit(FSCACHE_COOKIE_INVALIDATING, &cookie->flags)) wake_up_bit(&cookie->flags, FSCACHE_COOKIE_INVALIDATING); _leave(" [ok]"); return transit_to(UPDATE_OBJECT); nomem: fscache_mark_object_dead(object); fscache_unuse_cookie(object); _leave(" [ENOMEM]"); return transit_to(KILL_OBJECT); submit_op_failed: fscache_mark_object_dead(object); spin_unlock(&cookie->lock); fscache_unuse_cookie(object); kfree(op); _leave(" [EIO]"); return transit_to(KILL_OBJECT); } static const struct fscache_state *fscache_invalidate_object(struct fscache_object *object, int event) { const struct fscache_state *s; fscache_stat(&fscache_n_invalidates_run); fscache_stat(&fscache_n_cop_invalidate_object); s = _fscache_invalidate_object(object, event); fscache_stat_d(&fscache_n_cop_invalidate_object); return s; } /* * Asynchronously update an object. */ static const struct fscache_state *fscache_update_object(struct fscache_object *object, int event) { _enter("{OBJ%x},%d", object->debug_id, event); fscache_stat(&fscache_n_updates_run); fscache_stat(&fscache_n_cop_update_object); object->cache->ops->update_object(object); fscache_stat_d(&fscache_n_cop_update_object); _leave(""); return transit_to(WAIT_FOR_CMD); } /** * fscache_object_retrying_stale - Note retrying stale object * @object: The object that will be retried * * Note that an object lookup found an on-disk object that was adjudged to be * stale and has been deleted. The lookup will be retried. */ void fscache_object_retrying_stale(struct fscache_object *object) { fscache_stat(&fscache_n_cache_no_space_reject); } EXPORT_SYMBOL(fscache_object_retrying_stale); /** * fscache_object_mark_killed - Note that an object was killed * @object: The object that was culled * @why: The reason the object was killed. * * Note that an object was killed. Returns true if the object was * already marked killed, false if it wasn't. */ void fscache_object_mark_killed(struct fscache_object *object, enum fscache_why_object_killed why) { if (test_and_set_bit(FSCACHE_OBJECT_KILLED_BY_CACHE, &object->flags)) { pr_err("Error: Object already killed by cache [%s]\n", object->cache->identifier); return; } switch (why) { case FSCACHE_OBJECT_NO_SPACE: fscache_stat(&fscache_n_cache_no_space_reject); break; case FSCACHE_OBJECT_IS_STALE: fscache_stat(&fscache_n_cache_stale_objects); break; case FSCACHE_OBJECT_WAS_RETIRED: fscache_stat(&fscache_n_cache_retired_objects); break; case FSCACHE_OBJECT_WAS_CULLED: fscache_stat(&fscache_n_cache_culled_objects); break; } } EXPORT_SYMBOL(fscache_object_mark_killed);


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