/**
* fscache_enqueue_operation - Enqueue an operation for processing
* @op: The operation to enqueue
*
* Enqueue an operation for processing by the FS-Cache thread pool.
*
* This will get its own ref on the object.
*/
void fscache_enqueue_operation(struct fscache_operation *op)
{
_enter("{OBJ%x OP%x,%u}",
op->object->debug_id, op->debug_id, atomic_read(&op->usage));
fscache_set_op_state(op, "EnQ");
ASSERT(list_empty(&op->pend_link));
ASSERT(op->processor != NULL);
ASSERT(fscache_object_is_available(op->object));
ASSERTCMP(atomic_read(&op->usage), >, 0);
ASSERTCMP(op->state, ==, FSCACHE_OP_ST_IN_PROGRESS);
fscache_stat(&fscache_n_op_enqueue);
switch (op->flags & FSCACHE_OP_TYPE) {
case FSCACHE_OP_FAST:
_debug("queue fast");
atomic_inc(&op->usage);
if (!schedule_work(&op->fast_work))
fscache_put_operation(op);
break;
case FSCACHE_OP_SLOW:
_debug("queue slow");
slow_work_enqueue(&op->slow_work);
break;
case FSCACHE_OP_MYTHREAD:
_debug("queue for caller's attention");
break;
default:
printk(KERN_ERR "FS-Cache: Unexpected op type %lx",
op->flags);
BUG();
break;
}
}
/**
* fscache_enqueue_operation - Enqueue an operation for processing
* @op: The operation to enqueue
*
* Enqueue an operation for processing by the FS-Cache thread pool.
*
* This will get its own ref on the object.
*/
void fscache_enqueue_operation(struct fscache_operation *op)
{
_enter("{OBJ%x OP%x,%u}",
op->object->debug_id, op->debug_id, atomic_read(&op->usage));
ASSERT(list_empty(&op->pend_link));
ASSERT(op->processor != NULL);
ASSERT(fscache_object_is_available(op->object));
ASSERTCMP(atomic_read(&op->usage), >, 0);
ASSERTCMP(op->state, ==, FSCACHE_OP_ST_IN_PROGRESS);
fscache_stat(&fscache_n_op_enqueue);
switch (op->flags & FSCACHE_OP_TYPE) {
case FSCACHE_OP_ASYNC:
_debug("queue async");
atomic_inc(&op->usage);
if (!queue_work(fscache_op_wq, &op->work))
fscache_put_operation(op);
break;
case FSCACHE_OP_MYTHREAD:
_debug("queue for caller's attention");
break;
default:
pr_err("Unexpected op type %lx", op->flags);
BUG();
break;
}
}
/*
* 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* be withdrawn by either party till we've finished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);
}
/*
* 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);
}
