#define FSCACHE_DEBUG_LEVEL COOKIE
#include <linux/module.h>
#include <linux/slab.h>
+#include <linux/prefetch.h>
#include "internal.h"
-const char *fscache_object_states[FSCACHE_OBJECT__NSTATES] = {
- [FSCACHE_OBJECT_INIT] = "OBJECT_INIT",
- [FSCACHE_OBJECT_LOOKING_UP] = "OBJECT_LOOKING_UP",
- [FSCACHE_OBJECT_CREATING] = "OBJECT_CREATING",
- [FSCACHE_OBJECT_AVAILABLE] = "OBJECT_AVAILABLE",
- [FSCACHE_OBJECT_ACTIVE] = "OBJECT_ACTIVE",
- [FSCACHE_OBJECT_INVALIDATING] = "OBJECT_INVALIDATING",
- [FSCACHE_OBJECT_UPDATING] = "OBJECT_UPDATING",
- [FSCACHE_OBJECT_DYING] = "OBJECT_DYING",
- [FSCACHE_OBJECT_LC_DYING] = "OBJECT_LC_DYING",
- [FSCACHE_OBJECT_ABORT_INIT] = "OBJECT_ABORT_INIT",
- [FSCACHE_OBJECT_RELEASING] = "OBJECT_RELEASING",
- [FSCACHE_OBJECT_RECYCLING] = "OBJECT_RECYCLING",
- [FSCACHE_OBJECT_WITHDRAWING] = "OBJECT_WITHDRAWING",
- [FSCACHE_OBJECT_DEAD] = "OBJECT_DEAD",
+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 }
};
-EXPORT_SYMBOL(fscache_object_states);
-
-const char fscache_object_states_short[FSCACHE_OBJECT__NSTATES][5] = {
- [FSCACHE_OBJECT_INIT] = "INIT",
- [FSCACHE_OBJECT_LOOKING_UP] = "LOOK",
- [FSCACHE_OBJECT_CREATING] = "CRTN",
- [FSCACHE_OBJECT_AVAILABLE] = "AVBL",
- [FSCACHE_OBJECT_ACTIVE] = "ACTV",
- [FSCACHE_OBJECT_INVALIDATING] = "INVL",
- [FSCACHE_OBJECT_UPDATING] = "UPDT",
- [FSCACHE_OBJECT_DYING] = "DYNG",
- [FSCACHE_OBJECT_LC_DYING] = "LCDY",
- [FSCACHE_OBJECT_ABORT_INIT] = "ABTI",
- [FSCACHE_OBJECT_RELEASING] = "RELS",
- [FSCACHE_OBJECT_RECYCLING] = "RCYC",
- [FSCACHE_OBJECT_WITHDRAWING] = "WTHD",
- [FSCACHE_OBJECT_DEAD] = "DEAD",
+
+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 void fscache_initialise_object(struct fscache_object *);
-static void fscache_lookup_object(struct fscache_object *);
-static void fscache_object_available(struct fscache_object *);
-static void fscache_invalidate_object(struct fscache_object *);
-static void fscache_release_object(struct fscache_object *);
-static void fscache_withdraw_object(struct fscache_object *);
-static void fscache_enqueue_dependents(struct fscache_object *);
+static bool fscache_enqueue_dependents(struct fscache_object *, int);
static void fscache_dequeue_object(struct fscache_object *);
/*
object->debug_id, parent->debug_id, parent->n_ops);
spin_lock_nested(&parent->lock, 1);
- parent->n_ops--;
parent->n_obj_ops--;
+ parent->n_ops--;
if (parent->n_ops == 0)
fscache_raise_event(parent, FSCACHE_OBJECT_EV_CLEARED);
spin_unlock(&parent->lock);
}
/*
- * Notify netfs of invalidation completion.
+ * Object state machine dispatcher.
*/
-static inline void fscache_invalidation_complete(struct fscache_cookie *cookie)
+static void fscache_object_sm_dispatcher(struct fscache_object *object)
{
- if (test_and_clear_bit(FSCACHE_COOKIE_INVALIDATING, &cookie->flags))
- wake_up_bit(&cookie->flags, FSCACHE_COOKIE_INVALIDATING);
-}
-
-/*
- * process events that have been sent to an object's state machine
- * - initiates parent lookup
- * - does object lookup
- * - does object creation
- * - does object recycling and retirement
- * - does object withdrawal
- */
-static void fscache_object_state_machine(struct fscache_object *object)
-{
- enum fscache_object_state new_state;
- struct fscache_cookie *cookie;
- int event;
+ 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, fscache_object_states[object->state],
- object->events);
-
- switch (object->state) {
- /* wait for the parent object to become ready */
- case FSCACHE_OBJECT_INIT:
- object->event_mask =
- FSCACHE_OBJECT_EVENTS_MASK &
- ~(1 << FSCACHE_OBJECT_EV_CLEARED);
- fscache_initialise_object(object);
- goto done;
-
- /* look up the object metadata on disk */
- case FSCACHE_OBJECT_LOOKING_UP:
- fscache_lookup_object(object);
- goto lookup_transit;
-
- /* create the object metadata on disk */
- case FSCACHE_OBJECT_CREATING:
- fscache_lookup_object(object);
- goto lookup_transit;
-
- /* handle an object becoming available; start pending
- * operations and queue dependent operations for processing */
- case FSCACHE_OBJECT_AVAILABLE:
- fscache_object_available(object);
- goto active_transit;
-
- /* normal running state */
- case FSCACHE_OBJECT_ACTIVE:
- goto active_transit;
-
- /* Invalidate an object on disk */
- case FSCACHE_OBJECT_INVALIDATING:
- clear_bit(FSCACHE_OBJECT_EV_INVALIDATE, &object->events);
- fscache_stat(&fscache_n_invalidates_run);
- fscache_stat(&fscache_n_cop_invalidate_object);
- fscache_invalidate_object(object);
- fscache_stat_d(&fscache_n_cop_invalidate_object);
- fscache_raise_event(object, FSCACHE_OBJECT_EV_UPDATE);
- goto active_transit;
-
- /* update the object metadata on disk */
- case FSCACHE_OBJECT_UPDATING:
- clear_bit(FSCACHE_OBJECT_EV_UPDATE, &object->events);
- 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);
- goto active_transit;
-
- /* handle an object dying during lookup or creation */
- case FSCACHE_OBJECT_LC_DYING:
- object->event_mask &= ~(1 << FSCACHE_OBJECT_EV_UPDATE);
- fscache_stat(&fscache_n_cop_lookup_complete);
- object->cache->ops->lookup_complete(object);
- fscache_stat_d(&fscache_n_cop_lookup_complete);
-
- spin_lock(&object->lock);
- object->state = FSCACHE_OBJECT_DYING;
- cookie = object->cookie;
- if (cookie) {
- if (test_and_clear_bit(FSCACHE_COOKIE_LOOKING_UP,
- &cookie->flags))
- wake_up_bit(&cookie->flags,
- FSCACHE_COOKIE_LOOKING_UP);
- if (test_and_clear_bit(FSCACHE_COOKIE_CREATING,
- &cookie->flags))
- wake_up_bit(&cookie->flags,
- FSCACHE_COOKIE_CREATING);
+ 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;
+ }
}
- spin_unlock(&object->lock);
+ }
- fscache_done_parent_op(object);
+ /* 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;
+ }
+ }
- /* wait for completion of all active operations on this object
- * and the death of all child objects of this object */
- case FSCACHE_OBJECT_DYING:
- dying:
- clear_bit(FSCACHE_OBJECT_EV_CLEARED, &object->events);
- spin_lock(&object->lock);
- _debug("dying OBJ%x {%d,%d}",
- object->debug_id, object->n_ops, object->n_children);
- if (object->n_ops == 0 && object->n_children == 0) {
- object->event_mask &=
- ~(1 << FSCACHE_OBJECT_EV_CLEARED);
- object->event_mask |=
- (1 << FSCACHE_OBJECT_EV_WITHDRAW) |
- (1 << FSCACHE_OBJECT_EV_RETIRE) |
- (1 << FSCACHE_OBJECT_EV_RELEASE) |
- (1 << FSCACHE_OBJECT_EV_ERROR);
- } else {
- object->event_mask &=
- ~((1 << FSCACHE_OBJECT_EV_WITHDRAW) |
- (1 << FSCACHE_OBJECT_EV_RETIRE) |
- (1 << FSCACHE_OBJECT_EV_RELEASE) |
- (1 << FSCACHE_OBJECT_EV_ERROR));
- object->event_mask |=
- 1 << FSCACHE_OBJECT_EV_CLEARED;
+ /* The event mask didn't include all the tabled bits */
+ BUG();
}
- spin_unlock(&object->lock);
- fscache_enqueue_dependents(object);
- fscache_start_operations(object);
- goto terminal_transit;
-
- /* handle an abort during initialisation */
- case FSCACHE_OBJECT_ABORT_INIT:
- _debug("handle abort init %lx", object->events);
- object->event_mask &= ~(1 << FSCACHE_OBJECT_EV_UPDATE);
-
- spin_lock(&object->lock);
- fscache_dequeue_object(object);
-
- object->state = FSCACHE_OBJECT_DYING;
- if (test_and_clear_bit(FSCACHE_COOKIE_CREATING,
- &object->cookie->flags))
- wake_up_bit(&object->cookie->flags,
- FSCACHE_COOKIE_CREATING);
- spin_unlock(&object->lock);
- goto dying;
-
- /* handle the netfs releasing an object and possibly marking it
- * obsolete too */
- case FSCACHE_OBJECT_RELEASING:
- case FSCACHE_OBJECT_RECYCLING:
- object->event_mask &=
- ~((1 << FSCACHE_OBJECT_EV_WITHDRAW) |
- (1 << FSCACHE_OBJECT_EV_RETIRE) |
- (1 << FSCACHE_OBJECT_EV_RELEASE) |
- (1 << FSCACHE_OBJECT_EV_ERROR));
- fscache_release_object(object);
- spin_lock(&object->lock);
- object->state = FSCACHE_OBJECT_DEAD;
- spin_unlock(&object->lock);
- fscache_stat(&fscache_n_object_dead);
- goto terminal_transit;
-
- /* handle the parent cache of this object being withdrawn from
- * active service */
- case FSCACHE_OBJECT_WITHDRAWING:
- object->event_mask &=
- ~((1 << FSCACHE_OBJECT_EV_WITHDRAW) |
- (1 << FSCACHE_OBJECT_EV_RETIRE) |
- (1 << FSCACHE_OBJECT_EV_RELEASE) |
- (1 << FSCACHE_OBJECT_EV_ERROR));
- fscache_withdraw_object(object);
- spin_lock(&object->lock);
- object->state = FSCACHE_OBJECT_DEAD;
- spin_unlock(&object->lock);
- fscache_stat(&fscache_n_object_dead);
- goto terminal_transit;
-
- /* complain about the object being woken up once it is
- * deceased */
- case FSCACHE_OBJECT_DEAD:
- printk(KERN_ERR "FS-Cache:"
- " Unexpected event in dead state %lx\n",
- object->events & object->event_mask);
- BUG();
-
- default:
- printk(KERN_ERR "FS-Cache: Unknown object state %u\n",
- object->state);
- BUG();
- }
-
- /* determine the transition from a lookup state */
-lookup_transit:
- event = fls(object->events & object->event_mask) - 1;
- switch (event) {
- case FSCACHE_OBJECT_EV_WITHDRAW:
- case FSCACHE_OBJECT_EV_RETIRE:
- case FSCACHE_OBJECT_EV_RELEASE:
- case FSCACHE_OBJECT_EV_ERROR:
- new_state = FSCACHE_OBJECT_LC_DYING;
- goto change_state;
- case FSCACHE_OBJECT_EV_INVALIDATE:
- new_state = FSCACHE_OBJECT_INVALIDATING;
- goto change_state;
- case FSCACHE_OBJECT_EV_REQUEUE:
- goto done;
- case -1:
- goto done; /* sleep until event */
- default:
- goto unsupported_event;
+ /* Randomly woke up */
+ goto unmask_events;
}
- /* determine the transition from an active state */
-active_transit:
- event = fls(object->events & object->event_mask) - 1;
- switch (event) {
- case FSCACHE_OBJECT_EV_WITHDRAW:
- case FSCACHE_OBJECT_EV_RETIRE:
- case FSCACHE_OBJECT_EV_RELEASE:
- case FSCACHE_OBJECT_EV_ERROR:
- new_state = FSCACHE_OBJECT_DYING;
- goto change_state;
- case FSCACHE_OBJECT_EV_INVALIDATE:
- new_state = FSCACHE_OBJECT_INVALIDATING;
- goto change_state;
- case FSCACHE_OBJECT_EV_UPDATE:
- new_state = FSCACHE_OBJECT_UPDATING;
- goto change_state;
- case -1:
- new_state = FSCACHE_OBJECT_ACTIVE;
- goto change_state; /* sleep until event */
- default:
- goto unsupported_event;
- }
+execute_work_state:
+ _debug("{OBJ%x} exec %s", object->debug_id, state->name);
- /* determine the transition from a terminal state */
-terminal_transit:
- event = fls(object->events & object->event_mask) - 1;
- switch (event) {
- case FSCACHE_OBJECT_EV_WITHDRAW:
- new_state = FSCACHE_OBJECT_WITHDRAWING;
- goto change_state;
- case FSCACHE_OBJECT_EV_RETIRE:
- new_state = FSCACHE_OBJECT_RECYCLING;
- goto change_state;
- case FSCACHE_OBJECT_EV_RELEASE:
- new_state = FSCACHE_OBJECT_RELEASING;
- goto change_state;
- case FSCACHE_OBJECT_EV_ERROR:
- new_state = FSCACHE_OBJECT_WITHDRAWING;
- goto change_state;
- case FSCACHE_OBJECT_EV_CLEARED:
- new_state = FSCACHE_OBJECT_DYING;
- goto change_state;
- case -1:
- goto done; /* sleep until event */
- default:
- goto unsupported_event;
+ 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;
}
-change_state:
- spin_lock(&object->lock);
- object->state = new_state;
- spin_unlock(&object->lock);
+ _debug("{OBJ%x} %s -> %s",
+ object->debug_id, state->name, new_state->name);
+ object->state = state = new_state;
-done:
- _leave(" [->%s]", fscache_object_states[object->state]);
- return;
+ if (state->work) {
+ if (unlikely(state->work == ((void *)2UL))) {
+ _leave(" [dead]");
+ return;
+ }
+ goto restart_masked;
+ }
-unsupported_event:
- printk(KERN_ERR "FS-Cache:"
- " Unsupported event %d [%lx/%lx] in state %s\n",
- event, object->events, object->event_mask,
- fscache_object_states[object->state]);
- BUG();
+ /* 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
*/
-void fscache_object_work_func(struct work_struct *work)
+static void fscache_object_work_func(struct work_struct *work)
{
struct fscache_object *object =
container_of(work, struct fscache_object, work);
_enter("{OBJ%x}", object->debug_id);
start = jiffies;
- fscache_object_state_machine(object);
+ fscache_object_sm_dispatcher(object);
fscache_hist(fscache_objs_histogram, start);
- if (object->events & object->event_mask)
- fscache_enqueue_object(object);
- clear_bit(FSCACHE_OBJECT_EV_REQUEUE, &object->events);
fscache_put_object(object);
}
-EXPORT_SYMBOL(fscache_object_work_func);
+
+/**
+ * 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;
+
+ 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);
+
+/*
+ * 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
* 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
- * - an object's cookie is pinned until we clear FSCACHE_COOKIE_CREATING on the
- * leaf-most cookies of the object and all its children
*/
-static void fscache_initialise_object(struct fscache_object *object)
+static const struct fscache_state *fscache_initialise_object(struct fscache_object *object,
+ int event)
{
struct fscache_object *parent;
+ bool success;
- _enter("");
- ASSERT(object->cookie != NULL);
- ASSERT(object->cookie->parent != NULL);
-
- if (object->events & ((1 << FSCACHE_OBJECT_EV_ERROR) |
- (1 << FSCACHE_OBJECT_EV_RELEASE) |
- (1 << FSCACHE_OBJECT_EV_RETIRE) |
- (1 << FSCACHE_OBJECT_EV_WITHDRAW))) {
- _debug("abort init %lx", object->events);
- spin_lock(&object->lock);
- object->state = FSCACHE_OBJECT_ABORT_INIT;
- spin_unlock(&object->lock);
- return;
- }
+ _enter("{OBJ%x},%d", object->debug_id, event);
- spin_lock(&object->cookie->lock);
- spin_lock_nested(&object->cookie->parent->lock, 1);
+ ASSERT(list_empty(&object->dep_link));
parent = object->parent;
if (!parent) {
- _debug("no parent");
- set_bit(FSCACHE_OBJECT_EV_WITHDRAW, &object->events);
- } else {
- spin_lock(&object->lock);
- spin_lock_nested(&parent->lock, 1);
- _debug("parent %s", fscache_object_states[parent->state]);
-
- if (parent->state >= FSCACHE_OBJECT_DYING) {
- _debug("bad parent");
- set_bit(FSCACHE_OBJECT_EV_WITHDRAW, &object->events);
- } else if (parent->state < FSCACHE_OBJECT_AVAILABLE) {
- _debug("wait");
-
- /* we may get woken up in this state by child objects
- * binding on to us, so we need to make sure we don't
- * add ourself to the list multiple times */
- if (list_empty(&object->dep_link)) {
- fscache_stat(&fscache_n_cop_grab_object);
- object->cache->ops->grab_object(object);
- fscache_stat_d(&fscache_n_cop_grab_object);
- list_add(&object->dep_link,
- &parent->dependents);
-
- /* fscache_acquire_non_index_cookie() uses this
- * to wake the chain up */
- if (parent->state == FSCACHE_OBJECT_INIT)
- fscache_enqueue_object(parent);
- }
- } else {
- _debug("go");
- parent->n_ops++;
- parent->n_obj_ops++;
- object->lookup_jif = jiffies;
- object->state = FSCACHE_OBJECT_LOOKING_UP;
- set_bit(FSCACHE_OBJECT_EV_REQUEUE, &object->events);
- }
+ _leave(" [no parent]");
+ return transit_to(DROP_OBJECT);
+ }
- spin_unlock(&parent->lock);
- spin_unlock(&object->lock);
+ _debug("parent: %s of:%lx", parent->state->name, parent->flags);
+
+ if (fscache_object_is_dying(parent)) {
+ _leave(" [bad parent]");
+ return transit_to(DROP_OBJECT);
}
- spin_unlock(&object->cookie->parent->lock);
- spin_unlock(&object->cookie->lock);
+ 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
- * - an object's cookie is pinned until we clear FSCACHE_COOKIE_CREATING on the
- * leaf-most cookies of the object and all its children
*/
-static void fscache_lookup_object(struct fscache_object *object)
+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;
+ struct fscache_object *parent = object->parent;
int ret;
- _enter("");
+ _enter("{OBJ%x},%d", object->debug_id, event);
+
+ object->oob_table = fscache_osm_lookup_oob;
- parent = object->parent;
ASSERT(parent != NULL);
ASSERTCMP(parent->n_ops, >, 0);
ASSERTCMP(parent->n_obj_ops, >, 0);
/* make sure the parent is still available */
- ASSERTCMP(parent->state, >=, FSCACHE_OBJECT_AVAILABLE);
-
- if (parent->state >= FSCACHE_OBJECT_DYING ||
- test_bit(FSCACHE_IOERROR, &object->cache->flags)) {
- _debug("unavailable");
- set_bit(FSCACHE_OBJECT_EV_WITHDRAW, &object->events);
- _leave("");
- return;
+ 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/%s\" in \"%s\"",
- parent->cookie->def->name, cookie->def->name,
- object->cache->tag->name);
+ _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);
- if (test_bit(FSCACHE_OBJECT_EV_ERROR, &object->events))
- set_bit(FSCACHE_COOKIE_UNAVAILABLE, &cookie->flags);
+ 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);
- set_bit(FSCACHE_OBJECT_EV_REQUEUE, &object->events);
+ _leave(" [timeout]");
+ return NO_TRANSIT;
}
- _leave("");
+ if (ret < 0) {
+ _leave(" [error]");
+ return transit_to(LOOKUP_FAILURE);
+ }
+
+ _leave(" [ok]");
+ return transit_to(OBJECT_AVAILABLE);
}
/**
{
struct fscache_cookie *cookie = object->cookie;
- _enter("{OBJ%x,%s}",
- object->debug_id, fscache_object_states[object->state]);
+ _enter("{OBJ%x,%s}", object->debug_id, object->state->name);
- spin_lock(&object->lock);
- if (object->state == FSCACHE_OBJECT_LOOKING_UP) {
+ if (!test_and_set_bit(FSCACHE_OBJECT_IS_LOOKED_UP, &object->flags)) {
fscache_stat(&fscache_n_object_lookups_negative);
- /* transit here to allow write requests to begin stacking up
- * and read requests to begin returning ENODATA */
- object->state = FSCACHE_OBJECT_CREATING;
- spin_unlock(&object->lock);
-
- set_bit(FSCACHE_COOKIE_PENDING_FILL, &cookie->flags);
+ /* Allow write requests to begin stacking up and read requests to begin
+ * returning ENODATA.
+ */
set_bit(FSCACHE_COOKIE_NO_DATA_YET, &cookie->flags);
_debug("wake up lookup %p", &cookie->flags);
- smp_mb__before_clear_bit();
- clear_bit(FSCACHE_COOKIE_LOOKING_UP, &cookie->flags);
- smp_mb__after_clear_bit();
+ clear_bit_unlock(FSCACHE_COOKIE_LOOKING_UP, &cookie->flags);
wake_up_bit(&cookie->flags, FSCACHE_COOKIE_LOOKING_UP);
- set_bit(FSCACHE_OBJECT_EV_REQUEUE, &object->events);
- } else {
- ASSERTCMP(object->state, ==, FSCACHE_OBJECT_CREATING);
- spin_unlock(&object->lock);
}
-
_leave("");
}
EXPORT_SYMBOL(fscache_object_lookup_negative);
{
struct fscache_cookie *cookie = object->cookie;
- _enter("{OBJ%x,%s}",
- object->debug_id, fscache_object_states[object->state]);
+ _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 */
- spin_lock(&object->lock);
- if (object->state == FSCACHE_OBJECT_LOOKING_UP) {
+ if (!test_and_set_bit(FSCACHE_OBJECT_IS_LOOKED_UP, &object->flags)) {
fscache_stat(&fscache_n_object_lookups_positive);
- clear_bit(FSCACHE_COOKIE_NO_DATA_YET, &cookie->flags);
+ /* We do (presumably) have data */
+ clear_bit_unlock(FSCACHE_COOKIE_NO_DATA_YET, &cookie->flags);
- object->state = FSCACHE_OBJECT_AVAILABLE;
- spin_unlock(&object->lock);
-
- smp_mb__before_clear_bit();
- clear_bit(FSCACHE_COOKIE_LOOKING_UP, &cookie->flags);
- smp_mb__after_clear_bit();
+ /* 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);
- set_bit(FSCACHE_OBJECT_EV_REQUEUE, &object->events);
} else {
- ASSERTCMP(object->state, ==, FSCACHE_OBJECT_CREATING);
fscache_stat(&fscache_n_object_created);
-
- object->state = FSCACHE_OBJECT_AVAILABLE;
- spin_unlock(&object->lock);
- set_bit(FSCACHE_OBJECT_EV_REQUEUE, &object->events);
- smp_wmb();
}
- if (test_and_clear_bit(FSCACHE_COOKIE_CREATING, &cookie->flags))
- wake_up_bit(&cookie->flags, FSCACHE_COOKIE_CREATING);
-
+ set_bit(FSCACHE_OBJECT_IS_AVAILABLE, &object->flags);
_leave("");
}
EXPORT_SYMBOL(fscache_obtained_object);
/*
* handle an object that has just become available
*/
-static void fscache_object_available(struct fscache_object *object)
+static const struct fscache_state *fscache_object_available(struct fscache_object *object,
+ int event)
{
- _enter("{OBJ%x}", object->debug_id);
+ _enter("{OBJ%x},%d", object->debug_id, event);
- spin_lock(&object->lock);
+ object->oob_table = fscache_osm_run_oob;
- if (object->cookie &&
- test_and_clear_bit(FSCACHE_COOKIE_CREATING, &object->cookie->flags))
- wake_up_bit(&object->cookie->flags, FSCACHE_COOKIE_CREATING);
+ spin_lock(&object->lock);
fscache_done_parent_op(object);
if (object->n_in_progress == 0) {
fscache_stat(&fscache_n_cop_lookup_complete);
object->cache->ops->lookup_complete(object);
fscache_stat_d(&fscache_n_cop_lookup_complete);
- fscache_enqueue_dependents(object);
fscache_hist(fscache_obj_instantiate_histogram, object->lookup_jif);
fscache_stat(&fscache_n_object_avail);
_leave("");
+ return transit_to(JUMPSTART_DEPS);
}
/*
- * drop an object's attachments
+ * Wake up this object's dependent objects now that we've become available.
*/
-static void fscache_drop_object(struct fscache_object *object)
+static const struct fscache_state *fscache_jumpstart_dependents(struct fscache_object *object,
+ int event)
{
- struct fscache_object *parent = object->parent;
- struct fscache_cache *cache = object->cache;
+ _enter("{OBJ%x},%d", object->debug_id, event);
- _enter("{OBJ%x,%d}", object->debug_id, object->n_children);
+ if (!fscache_enqueue_dependents(object, FSCACHE_OBJECT_EV_PARENT_READY))
+ return NO_TRANSIT; /* Not finished; requeue */
+ return transit_to(WAIT_FOR_CMD);
+}
- ASSERTCMP(object->cookie, ==, NULL);
- ASSERT(hlist_unhashed(&object->cookie_link));
+/*
+ * Handle lookup or creation failute.
+ */
+static const struct fscache_state *fscache_lookup_failure(struct fscache_object *object,
+ int event)
+{
+ struct fscache_cookie *cookie;
- spin_lock(&cache->object_list_lock);
- list_del_init(&object->cache_link);
- spin_unlock(&cache->object_list_lock);
+ _enter("{OBJ%x},%d", object->debug_id, event);
- fscache_stat(&fscache_n_cop_drop_object);
- cache->ops->drop_object(object);
- fscache_stat_d(&fscache_n_cop_drop_object);
+ object->oob_event_mask = 0;
- if (parent) {
- _debug("release parent OBJ%x {%d}",
- parent->debug_id, parent->n_children);
+ fscache_stat(&fscache_n_cop_lookup_complete);
+ object->cache->ops->lookup_complete(object);
+ fscache_stat_d(&fscache_n_cop_lookup_complete);
- 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;
+ 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);
+
+ clear_bit(FSCACHE_OBJECT_IS_LIVE, &object->flags);
+ 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);
}
- /* this just shifts the object release to the work processor */
- fscache_put_object(object);
+ if (!list_empty(&object->dependents))
+ return transit_to(KILL_DEPENDENTS);
- _leave("");
+ return transit_to(WAIT_FOR_CLEARANCE);
}
/*
- * release or recycle an object that the netfs has discarded
+ * Kill dependent objects.
*/
-static void fscache_release_object(struct fscache_object *object)
+static const struct fscache_state *fscache_kill_dependents(struct fscache_object *object,
+ int event)
{
- _enter("");
+ _enter("{OBJ%x},%d", object->debug_id, event);
- fscache_drop_object(object);
+ if (!fscache_enqueue_dependents(object, FSCACHE_OBJECT_EV_KILL))
+ return NO_TRANSIT; /* Not finished */
+ return transit_to(WAIT_FOR_CLEARANCE);
}
/*
- * withdraw an object from active service
+ * Drop an object's attachments
*/
-static void fscache_withdraw_object(struct fscache_object *object)
+static const struct fscache_state *fscache_drop_object(struct fscache_object *object,
+ int event)
{
- struct fscache_cookie *cookie;
- bool detached;
+ struct fscache_object *parent = object->parent;
+ struct fscache_cookie *cookie = object->cookie;
+ struct fscache_cache *cache = object->cache;
+ bool awaken = false;
- _enter("");
+ _enter("{OBJ%x,%d},%d", object->debug_id, object->n_children, event);
- spin_lock(&object->lock);
- cookie = object->cookie;
- if (cookie) {
- /* need to get the cookie lock before the object lock, starting
- * from the object pointer */
- atomic_inc(&cookie->usage);
- spin_unlock(&object->lock);
+ ASSERT(cookie != NULL);
+ ASSERT(!hlist_unhashed(&object->cookie_link));
- detached = false;
- spin_lock(&cookie->lock);
- spin_lock(&object->lock);
+ /* 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 (test_and_clear_bit(FSCACHE_COOKIE_INVALIDATING, &cookie->flags))
+ awaken = true;
+ spin_unlock(&cookie->lock);
- if (object->cookie == cookie) {
- hlist_del_init(&object->cookie_link);
- object->cookie = NULL;
- fscache_invalidation_complete(cookie);
- detached = true;
- }
- spin_unlock(&cookie->lock);
- fscache_cookie_put(cookie);
- if (detached)
- fscache_cookie_put(cookie);
- }
+ 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);
- fscache_drop_object(object);
-}
+ /* 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);
-/*
- * withdraw an object from active service at the behest of the cache
- * - need break the links to a cached object cookie
- * - called under two situations:
- * (1) recycler decides to reclaim an in-use object
- * (2) a cache is unmounted
- * - have to take care as the cookie can be being relinquished by the netfs
- * simultaneously
- * - the object is pinned by the caller holding a refcount on it
- */
-void fscache_withdrawing_object(struct fscache_cache *cache,
- struct fscache_object *object)
-{
- bool enqueue = false;
+ fscache_stat(&fscache_n_cop_drop_object);
+ cache->ops->drop_object(object);
+ fscache_stat_d(&fscache_n_cop_drop_object);
- _enter(",OBJ%x", object->debug_id);
+ /* 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(&object->lock);
- if (object->state < FSCACHE_OBJECT_WITHDRAWING) {
- object->state = FSCACHE_OBJECT_WITHDRAWING;
- enqueue = true;
+ 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;
}
- spin_unlock(&object->lock);
- if (enqueue)
- fscache_enqueue_object(object);
+ /* 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);
}
/*
}
/*
- * discard a ref on a work item
+ * Discard a ref on an object
*/
static void fscache_put_object(struct fscache_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
*/
/**
* fscache_object_sleep_till_congested - Sleep until object wq is congested
- * @timoutp: Scheduler sleep timeout
+ * @timeoutp: Scheduler sleep timeout
*
* Allow an object handler to sleep until the object workqueue is congested.
*
EXPORT_SYMBOL_GPL(fscache_object_sleep_till_congested);
/*
- * enqueue the dependents of an object for metadata-type processing
- * - the caller must hold the object's lock
- * - this may cause an already locked object to wind up being processed again
+ * 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 void fscache_enqueue_dependents(struct fscache_object *object)
+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;
+ return true;
spin_lock(&object->lock);
struct fscache_object, dep_link);
list_del_init(&dep->dep_link);
-
- /* sort onto appropriate lists */
- fscache_enqueue_object(dep);
+ fscache_raise_event(dep, event);
fscache_put_object(dep);
- if (!list_empty(&object->dependents))
- cond_resched_lock(&object->lock);
+ 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
- * - the caller must hold object->lock
*/
-void fscache_dequeue_object(struct fscache_object *object)
+static void fscache_dequeue_object(struct fscache_object *object)
{
_enter("{OBJ%x}", object->debug_id);
* @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
+ * 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)
/*
* Asynchronously invalidate an object.
*/
-static void fscache_invalidate_object(struct fscache_object *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}", object->debug_id);
+ _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_COOKIE_RETIRED, &cookie->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);
/* Now we have to wait for in-progress reads and writes */
op = kzalloc(sizeof(*op), GFP_KERNEL);
- if (!op) {
- fscache_raise_event(object, FSCACHE_OBJECT_EV_ERROR);
- _leave(" [ENOMEM]");
- return;
- }
+ if (!op)
+ goto nomem;
fscache_operation_init(op, object->cache->ops->invalidate_object, NULL);
- op->flags = FSCACHE_OP_ASYNC | (1 << FSCACHE_OP_EXCLUSIVE);
+ 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)
/* We can allow read and write requests to come in once again. They'll
* queue up behind our exclusive invalidation operation.
*/
- fscache_invalidation_complete(cookie);
- _leave("");
- return;
+ 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:
+ clear_bit(FSCACHE_OBJECT_IS_LIVE, &object->flags);
+ fscache_unuse_cookie(object);
+ _leave(" [ENOMEM]");
+ return transit_to(KILL_OBJECT);
submit_op_failed:
+ clear_bit(FSCACHE_OBJECT_IS_LIVE, &object->flags);
spin_unlock(&cookie->lock);
kfree(op);
- fscache_raise_event(object, FSCACHE_OBJECT_EV_ERROR);
_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);
}
#define FSCACHE_OP_WAITING 4 /* cleared when op is woken */
#define FSCACHE_OP_EXCLUSIVE 5 /* exclusive op, other ops must wait */
#define FSCACHE_OP_DEC_READ_CNT 6 /* decrement object->n_reads on destruction */
-#define FSCACHE_OP_KEEP_FLAGS 0x0070 /* flags to keep when repurposing an op */
+#define FSCACHE_OP_UNUSE_COOKIE 7 /* call fscache_unuse_cookie() on completion */
+#define FSCACHE_OP_KEEP_FLAGS 0x00f0 /* flags to keep when repurposing an op */
enum fscache_operation_state state;
atomic_t usage;
void *context; /* netfs read context (pinned) */
struct list_head to_do; /* list of things to be done by the backend */
unsigned long start_time; /* time at which retrieval started */
- unsigned n_pages; /* number of pages to be retrieved */
+ atomic_t n_pages; /* number of pages to be retrieved */
};
typedef int (*fscache_page_retrieval_func_t)(struct fscache_retrieval *op,
static inline void fscache_retrieval_complete(struct fscache_retrieval *op,
int n_pages)
{
- op->n_pages -= n_pages;
- if (op->n_pages <= 0)
+ atomic_sub(n_pages, &op->n_pages);
+ if (atomic_read(&op->n_pages) <= 0)
fscache_op_complete(&op->op, true);
}
/**
* fscache_put_retrieval - Drop a reference to a retrieval operation
* @op: The retrieval operation affected
- * @n_pages: The number of pages to account for
*
* Drop a reference to a retrieval operation.
*/
struct fscache_cookie {
atomic_t usage; /* number of users of this cookie */
atomic_t n_children; /* number of children of this cookie */
+ atomic_t n_active; /* number of active users of netfs ptrs */
spinlock_t lock;
spinlock_t stores_lock; /* lock on page store tree */
struct hlist_head backing_objects; /* object(s) backing this file/index */
unsigned long flags;
#define FSCACHE_COOKIE_LOOKING_UP 0 /* T if non-index cookie being looked up still */
-#define FSCACHE_COOKIE_CREATING 1 /* T if non-index object being created still */
-#define FSCACHE_COOKIE_NO_DATA_YET 2 /* T if new object with no cached data yet */
-#define FSCACHE_COOKIE_PENDING_FILL 3 /* T if pending initial fill on object */
-#define FSCACHE_COOKIE_FILLING 4 /* T if filling object incrementally */
-#define FSCACHE_COOKIE_UNAVAILABLE 5 /* T if cookie is unavailable (error, etc) */
-#define FSCACHE_COOKIE_WAITING_ON_READS 6 /* T if cookie is waiting on reads */
-#define FSCACHE_COOKIE_INVALIDATING 7 /* T if cookie is being invalidated */
+#define FSCACHE_COOKIE_NO_DATA_YET 1 /* T if new object with no cached data yet */
+#define FSCACHE_COOKIE_UNAVAILABLE 2 /* T if cookie is unavailable (error, etc) */
+#define FSCACHE_COOKIE_INVALIDATING 3 /* T if cookie is being invalidated */
+#define FSCACHE_COOKIE_RELINQUISHED 4 /* T if cookie has been relinquished */
+#define FSCACHE_COOKIE_RETIRED 5 /* T if cookie was retired */
};
extern struct fscache_cookie fscache_fsdef_index;
* Event list for fscache_object::{event_mask,events}
*/
enum {
- FSCACHE_OBJECT_EV_REQUEUE, /* T if object should be requeued */
+ FSCACHE_OBJECT_EV_NEW_CHILD, /* T if object has a new child */
+ FSCACHE_OBJECT_EV_PARENT_READY, /* T if object's parent is ready */
FSCACHE_OBJECT_EV_UPDATE, /* T if object should be updated */
FSCACHE_OBJECT_EV_INVALIDATE, /* T if cache requested object invalidation */
FSCACHE_OBJECT_EV_CLEARED, /* T if accessors all gone */
FSCACHE_OBJECT_EV_ERROR, /* T if fatal error occurred during processing */
- FSCACHE_OBJECT_EV_RELEASE, /* T if netfs requested object release */
- FSCACHE_OBJECT_EV_RETIRE, /* T if netfs requested object retirement */
- FSCACHE_OBJECT_EV_WITHDRAW, /* T if cache requested object withdrawal */
+ FSCACHE_OBJECT_EV_KILL, /* T if netfs relinquished or cache withdrew object */
NR_FSCACHE_OBJECT_EVENTS
};
#define FSCACHE_OBJECT_EVENTS_MASK ((1UL << NR_FSCACHE_OBJECT_EVENTS) - 1)
+/*
+ * States for object state machine.
+ */
+struct fscache_transition {
+ unsigned long events;
+ const struct fscache_state *transit_to;
+};
+
+struct fscache_state {
+ char name[24];
+ char short_name[8];
+ const struct fscache_state *(*work)(struct fscache_object *object,
+ int event);
+ const struct fscache_transition transitions[];
+};
+
/*
* on-disk cache file or index handle
*/
struct fscache_object {
- enum fscache_object_state {
- FSCACHE_OBJECT_INIT, /* object in initial unbound state */
- FSCACHE_OBJECT_LOOKING_UP, /* looking up object */
- FSCACHE_OBJECT_CREATING, /* creating object */
-
- /* active states */
- FSCACHE_OBJECT_AVAILABLE, /* cleaning up object after creation */
- FSCACHE_OBJECT_ACTIVE, /* object is usable */
- FSCACHE_OBJECT_INVALIDATING, /* object is invalidating */
- FSCACHE_OBJECT_UPDATING, /* object is updating */
-
- /* terminal states */
- FSCACHE_OBJECT_DYING, /* object waiting for accessors to finish */
- FSCACHE_OBJECT_LC_DYING, /* object cleaning up after lookup/create */
- FSCACHE_OBJECT_ABORT_INIT, /* abort the init state */
- FSCACHE_OBJECT_RELEASING, /* releasing object */
- FSCACHE_OBJECT_RECYCLING, /* retiring object */
- FSCACHE_OBJECT_WITHDRAWING, /* withdrawing object */
- FSCACHE_OBJECT_DEAD, /* object is now dead */
- FSCACHE_OBJECT__NSTATES
- } state;
-
+ const struct fscache_state *state; /* Object state machine state */
+ const struct fscache_transition *oob_table; /* OOB state transition table */
int debug_id; /* debugging ID */
int n_children; /* number of child objects */
int n_ops; /* number of extant ops on object */
spinlock_t lock; /* state and operations lock */
unsigned long lookup_jif; /* time at which lookup started */
+ unsigned long oob_event_mask; /* OOB events this object is interested in */
unsigned long event_mask; /* events this object is interested in */
unsigned long events; /* events to be processed by this object
* (order is important - using fls) */
#define FSCACHE_OBJECT_LOCK 0 /* T if object is busy being processed */
#define FSCACHE_OBJECT_PENDING_WRITE 1 /* T if object has pending write */
#define FSCACHE_OBJECT_WAITING 2 /* T if object is waiting on its parent */
+#define FSCACHE_OBJECT_IS_LIVE 3 /* T if object is not withdrawn or relinquished */
+#define FSCACHE_OBJECT_IS_LOOKED_UP 4 /* T if object has been looked up */
+#define FSCACHE_OBJECT_IS_AVAILABLE 5 /* T if object has become active */
struct list_head cache_link; /* link in cache->object_list */
struct hlist_node cookie_link; /* link in cookie->backing_objects */
loff_t store_limit_l; /* current storage limit */
};
-extern const char *fscache_object_states[];
+extern void fscache_object_init(struct fscache_object *, struct fscache_cookie *,
+ struct fscache_cache *);
+extern void fscache_object_destroy(struct fscache_object *);
-#define fscache_object_is_active(obj) \
- (!test_bit(FSCACHE_IOERROR, &(obj)->cache->flags) && \
- (obj)->state >= FSCACHE_OBJECT_AVAILABLE && \
- (obj)->state < FSCACHE_OBJECT_DYING)
+extern void fscache_object_lookup_negative(struct fscache_object *object);
+extern void fscache_obtained_object(struct fscache_object *object);
-#define fscache_object_is_dead(obj) \
- (test_bit(FSCACHE_IOERROR, &(obj)->cache->flags) && \
- (obj)->state >= FSCACHE_OBJECT_DYING)
+static inline bool fscache_object_is_live(struct fscache_object *object)
+{
+ return test_bit(FSCACHE_OBJECT_IS_LIVE, &object->flags);
+}
-extern void fscache_object_work_func(struct work_struct *work);
+static inline bool fscache_object_is_dying(struct fscache_object *object)
+{
+ return !fscache_object_is_live(object);
+}
-/**
- * fscache_object_init - Initialise a cache object description
- * @object: Object description
- *
- * Initialise a cache object description to its basic values.
- *
- * See Documentation/filesystems/caching/backend-api.txt for a complete
- * description.
- */
-static inline
-void fscache_object_init(struct fscache_object *object,
- struct fscache_cookie *cookie,
- struct fscache_cache *cache)
+static inline bool fscache_object_is_available(struct fscache_object *object)
{
- atomic_inc(&cache->object_count);
-
- object->state = FSCACHE_OBJECT_INIT;
- 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 = object->event_mask = 0;
- object->flags = 0;
- object->store_limit = 0;
- object->store_limit_l = 0;
- object->cache = cache;
- object->cookie = cookie;
- object->parent = NULL;
+ return test_bit(FSCACHE_OBJECT_IS_AVAILABLE, &object->flags);
}
-extern void fscache_object_lookup_negative(struct fscache_object *object);
-extern void fscache_obtained_object(struct fscache_object *object);
+static inline bool fscache_object_is_active(struct fscache_object *object)
+{
+ return fscache_object_is_available(object) &&
+ fscache_object_is_live(object) &&
+ !test_bit(FSCACHE_IOERROR, &object->cache->flags);
+}
-#ifdef CONFIG_FSCACHE_OBJECT_LIST
-extern void fscache_object_destroy(struct fscache_object *object);
-#else
-#define fscache_object_destroy(object) do {} while(0)
-#endif
+static inline bool fscache_object_is_dead(struct fscache_object *object)
+{
+ return fscache_object_is_dying(object) &&
+ test_bit(FSCACHE_IOERROR, &object->cache->flags);
+}
/**
* fscache_object_destroyed - Note destruction of an object in a cache
op->end_io_func(page, op->context, error);
}
+/**
+ * fscache_use_cookie - Request usage of cookie attached to an object
+ * @object: Object description
+ *
+ * Request usage of the cookie attached to an object. NULL is returned if the
+ * relinquishment had reduced the cookie usage count to 0.
+ */
+static inline bool fscache_use_cookie(struct fscache_object *object)
+{
+ struct fscache_cookie *cookie = object->cookie;
+ return atomic_inc_not_zero(&cookie->n_active) != 0;
+}
+
+/**
+ * fscache_unuse_cookie - Cease usage of cookie attached to an object
+ * @object: Object description
+ *
+ * Cease usage of the cookie attached to an object. When the users count
+ * reaches zero then the cookie relinquishment will be permitted to proceed.
+ */
+static inline void fscache_unuse_cookie(struct fscache_object *object)
+{
+ struct fscache_cookie *cookie = object->cookie;
+ if (atomic_dec_and_test(&cookie->n_active))
+ wake_up_atomic_t(&cookie->n_active);
+}
+
/*
* out-of-line cache backend functions
*/
projects / linux-imx.git / commitdiff