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-rw-r--r--fs/fscache/object.c1125
1 files changed, 0 insertions, 1125 deletions
diff --git a/fs/fscache/object.c b/fs/fscache/object.c
deleted file mode 100644
index 6a675652129b..000000000000
--- a/fs/fscache/object.c
+++ /dev/null
@@ -1,1125 +0,0 @@
-// SPDX-License-Identifier: GPL-2.0-or-later
-/* FS-Cache object state machine handler
- *
- * Copyright (C) 2007 Red Hat, Inc. All Rights Reserved.
- * Written by David Howells (dhowells@redhat.com)
- *
- * See Documentation/filesystems/caching/object.rst 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);
-static const struct fscache_state *fscache_object_dead(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(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", fscache_object_dead);
-
-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 *,
- enum fscache_obj_ref_trace);
-static void fscache_put_object(struct fscache_object *,
- enum fscache_obj_ref_trace);
-static bool fscache_enqueue_dependents(struct fscache_object *, int);
-static void fscache_dequeue_object(struct fscache_object *);
-static void fscache_update_aux_data(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;
- bool oob;
- 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);
- oob = true;
- 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;
- }
- }
- }
- oob = false;
-
- /* 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;
- trace_fscache_osm(object, state,
- true, false, event);
- 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);
-
- trace_fscache_osm(object, state, false, oob, event);
- new_state = state->work(object, event);
- event = -1;
- if (new_state == NO_TRANSIT) {
- _debug("{OBJ%x} %s notrans", object->debug_id, state->name);
- if (unlikely(state == STATE(OBJECT_DEAD))) {
- _leave(" [dead]");
- return;
- }
- 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 == STATE(OBJECT_DEAD))) {
- _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);
-
- _enter("{OBJ%x}", object->debug_id);
-
- fscache_object_sm_dispatcher(object);
- fscache_put_object(object, fscache_obj_put_work);
-}
-
-/**
- * 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.rst 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;
- fscache_cookie_get(cookie, fscache_cookie_get_attach_object);
- 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, fscache_obj_get_add_to_deps)) {
- 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++;
- 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);
-
- 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_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 (test_bit(FSCACHE_OBJECT_RETIRED, &object->flags)) {
- /* Reject any new read/write ops and abort any that are pending. */
- clear_bit(FSCACHE_OBJECT_PENDING_WRITE, &object->flags);
- fscache_cancel_all_ops(object);
- }
-
- 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));
-
- if (test_bit(FSCACHE_COOKIE_AUX_UPDATED, &cookie->flags)) {
- _debug("final update");
- fscache_update_aux_data(object);
- }
-
- /* 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);
- if (test_and_clear_bit(FSCACHE_COOKIE_LOOKING_UP, &cookie->flags))
- wake_up_bit(&cookie->flags, FSCACHE_COOKIE_LOOKING_UP);
-
-
- /* 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_obj_put_drop_obj);
- 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,
- enum fscache_obj_ref_trace why)
-{
- int ret;
-
- fscache_stat(&fscache_n_cop_grab_object);
- ret = object->cache->ops->grab_object(object, why) ? 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,
- enum fscache_obj_ref_trace why)
-{
- fscache_stat(&fscache_n_cop_put_object);
- object->cache->ops->put_object(object, why);
- 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)
-{
- /* We can get rid of the cookie now */
- fscache_cookie_put(object->cookie, fscache_cookie_put_object);
- 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, fscache_obj_get_queue) >= 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, fscache_obj_put_queue);
-
- 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, fscache_obj_put_enq_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
- * @object_size: The size of the object according to the server.
- *
- * 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,
- loff_t object_size)
-{
- 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, object_size);
- 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(radix_tree_empty(&object->cookie->stores));
- 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(cookie, op, object->cache->ops->invalidate_object,
- NULL, NULL);
- op->flags = FSCACHE_OP_ASYNC |
- (1 << FSCACHE_OP_EXCLUSIVE) |
- (1 << FSCACHE_OP_UNUSE_COOKIE);
- trace_fscache_page_op(cookie, NULL, op, fscache_page_op_invalidate);
-
- 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;
-}
-
-/*
- * Update auxiliary data.
- */
-static void fscache_update_aux_data(struct fscache_object *object)
-{
- 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);
-}
-
-/*
- * 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_update_aux_data(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);
-
-/*
- * The object is dead. We can get here if an object gets queued by an event
- * that would lead to its death (such as EV_KILL) when the dispatcher is
- * already running (and so can be requeued) but hasn't yet cleared the event
- * mask.
- */
-static const struct fscache_state *fscache_object_dead(struct fscache_object *object,
- int event)
-{
- if (!test_and_set_bit(FSCACHE_OBJECT_RUN_AFTER_DEAD,
- &object->flags))
- return NO_TRANSIT;
-
- WARN(true, "FS-Cache object redispatched after death");
- return NO_TRANSIT;
-}