mirror of
https://github.com/AuxXxilium/linux_dsm_epyc7002.git
synced 2024-12-05 22:36:40 +07:00
2175bb06dc
Add a stat counter to count retirement events rather than ordinary release events (the retire argument to fscache_relinquish_cookie()). Signed-off-by: David Howells <dhowells@redhat.com>
515 lines
13 KiB
C
515 lines
13 KiB
C
/* netfs cookie management
|
|
*
|
|
* Copyright (C) 2004-2007 Red Hat, Inc. All Rights Reserved.
|
|
* Written by David Howells (dhowells@redhat.com)
|
|
*
|
|
* This program is free software; you can redistribute it and/or
|
|
* modify it under the terms of the GNU General Public License
|
|
* as published by the Free Software Foundation; either version
|
|
* 2 of the License, or (at your option) any later version.
|
|
*
|
|
* See Documentation/filesystems/caching/netfs-api.txt for more information on
|
|
* the netfs API.
|
|
*/
|
|
|
|
#define FSCACHE_DEBUG_LEVEL COOKIE
|
|
#include <linux/module.h>
|
|
#include <linux/slab.h>
|
|
#include "internal.h"
|
|
|
|
struct kmem_cache *fscache_cookie_jar;
|
|
|
|
static atomic_t fscache_object_debug_id = ATOMIC_INIT(0);
|
|
|
|
static int fscache_acquire_non_index_cookie(struct fscache_cookie *cookie);
|
|
static int fscache_alloc_object(struct fscache_cache *cache,
|
|
struct fscache_cookie *cookie);
|
|
static int fscache_attach_object(struct fscache_cookie *cookie,
|
|
struct fscache_object *object);
|
|
|
|
/*
|
|
* initialise an cookie jar slab element prior to any use
|
|
*/
|
|
void fscache_cookie_init_once(void *_cookie)
|
|
{
|
|
struct fscache_cookie *cookie = _cookie;
|
|
|
|
memset(cookie, 0, sizeof(*cookie));
|
|
spin_lock_init(&cookie->lock);
|
|
spin_lock_init(&cookie->stores_lock);
|
|
INIT_HLIST_HEAD(&cookie->backing_objects);
|
|
}
|
|
|
|
/*
|
|
* request a cookie to represent an object (index, datafile, xattr, etc)
|
|
* - parent specifies the parent object
|
|
* - the top level index cookie for each netfs is stored in the fscache_netfs
|
|
* struct upon registration
|
|
* - def points to the definition
|
|
* - the netfs_data will be passed to the functions pointed to in *def
|
|
* - all attached caches will be searched to see if they contain this object
|
|
* - index objects aren't stored on disk until there's a dependent file that
|
|
* needs storing
|
|
* - other objects are stored in a selected cache immediately, and all the
|
|
* indices forming the path to it are instantiated if necessary
|
|
* - we never let on to the netfs about errors
|
|
* - we may set a negative cookie pointer, but that's okay
|
|
*/
|
|
struct fscache_cookie *__fscache_acquire_cookie(
|
|
struct fscache_cookie *parent,
|
|
const struct fscache_cookie_def *def,
|
|
void *netfs_data)
|
|
{
|
|
struct fscache_cookie *cookie;
|
|
|
|
BUG_ON(!def);
|
|
|
|
_enter("{%s},{%s},%p",
|
|
parent ? (char *) parent->def->name : "<no-parent>",
|
|
def->name, netfs_data);
|
|
|
|
fscache_stat(&fscache_n_acquires);
|
|
|
|
/* if there's no parent cookie, then we don't create one here either */
|
|
if (!parent) {
|
|
fscache_stat(&fscache_n_acquires_null);
|
|
_leave(" [no parent]");
|
|
return NULL;
|
|
}
|
|
|
|
/* validate the definition */
|
|
BUG_ON(!def->get_key);
|
|
BUG_ON(!def->name[0]);
|
|
|
|
BUG_ON(def->type == FSCACHE_COOKIE_TYPE_INDEX &&
|
|
parent->def->type != FSCACHE_COOKIE_TYPE_INDEX);
|
|
|
|
/* allocate and initialise a cookie */
|
|
cookie = kmem_cache_alloc(fscache_cookie_jar, GFP_KERNEL);
|
|
if (!cookie) {
|
|
fscache_stat(&fscache_n_acquires_oom);
|
|
_leave(" [ENOMEM]");
|
|
return NULL;
|
|
}
|
|
|
|
atomic_set(&cookie->usage, 1);
|
|
atomic_set(&cookie->n_children, 0);
|
|
|
|
atomic_inc(&parent->usage);
|
|
atomic_inc(&parent->n_children);
|
|
|
|
cookie->def = def;
|
|
cookie->parent = parent;
|
|
cookie->netfs_data = netfs_data;
|
|
cookie->flags = 0;
|
|
|
|
/* radix tree insertion won't use the preallocation pool unless it's
|
|
* told it may not wait */
|
|
INIT_RADIX_TREE(&cookie->stores, GFP_NOFS & ~__GFP_WAIT);
|
|
|
|
switch (cookie->def->type) {
|
|
case FSCACHE_COOKIE_TYPE_INDEX:
|
|
fscache_stat(&fscache_n_cookie_index);
|
|
break;
|
|
case FSCACHE_COOKIE_TYPE_DATAFILE:
|
|
fscache_stat(&fscache_n_cookie_data);
|
|
break;
|
|
default:
|
|
fscache_stat(&fscache_n_cookie_special);
|
|
break;
|
|
}
|
|
|
|
/* if the object is an index then we need do nothing more here - we
|
|
* create indices on disk when we need them as an index may exist in
|
|
* multiple caches */
|
|
if (cookie->def->type != FSCACHE_COOKIE_TYPE_INDEX) {
|
|
if (fscache_acquire_non_index_cookie(cookie) < 0) {
|
|
atomic_dec(&parent->n_children);
|
|
__fscache_cookie_put(cookie);
|
|
fscache_stat(&fscache_n_acquires_nobufs);
|
|
_leave(" = NULL");
|
|
return NULL;
|
|
}
|
|
}
|
|
|
|
fscache_stat(&fscache_n_acquires_ok);
|
|
_leave(" = %p", cookie);
|
|
return cookie;
|
|
}
|
|
EXPORT_SYMBOL(__fscache_acquire_cookie);
|
|
|
|
/*
|
|
* acquire a non-index cookie
|
|
* - this must make sure the index chain is instantiated and instantiate the
|
|
* object representation too
|
|
*/
|
|
static int fscache_acquire_non_index_cookie(struct fscache_cookie *cookie)
|
|
{
|
|
struct fscache_object *object;
|
|
struct fscache_cache *cache;
|
|
uint64_t i_size;
|
|
int ret;
|
|
|
|
_enter("");
|
|
|
|
cookie->flags = 1 << FSCACHE_COOKIE_UNAVAILABLE;
|
|
|
|
/* now we need to see whether the backing objects for this cookie yet
|
|
* exist, if not there'll be nothing to search */
|
|
down_read(&fscache_addremove_sem);
|
|
|
|
if (list_empty(&fscache_cache_list)) {
|
|
up_read(&fscache_addremove_sem);
|
|
_leave(" = 0 [no caches]");
|
|
return 0;
|
|
}
|
|
|
|
/* select a cache in which to store the object */
|
|
cache = fscache_select_cache_for_object(cookie->parent);
|
|
if (!cache) {
|
|
up_read(&fscache_addremove_sem);
|
|
fscache_stat(&fscache_n_acquires_no_cache);
|
|
_leave(" = -ENOMEDIUM [no cache]");
|
|
return -ENOMEDIUM;
|
|
}
|
|
|
|
_debug("cache %s", cache->tag->name);
|
|
|
|
cookie->flags =
|
|
(1 << FSCACHE_COOKIE_LOOKING_UP) |
|
|
(1 << FSCACHE_COOKIE_CREATING) |
|
|
(1 << FSCACHE_COOKIE_NO_DATA_YET);
|
|
|
|
/* ask the cache to allocate objects for this cookie and its parent
|
|
* chain */
|
|
ret = fscache_alloc_object(cache, cookie);
|
|
if (ret < 0) {
|
|
up_read(&fscache_addremove_sem);
|
|
_leave(" = %d", ret);
|
|
return ret;
|
|
}
|
|
|
|
/* pass on how big the object we're caching is supposed to be */
|
|
cookie->def->get_attr(cookie->netfs_data, &i_size);
|
|
|
|
spin_lock(&cookie->lock);
|
|
if (hlist_empty(&cookie->backing_objects)) {
|
|
spin_unlock(&cookie->lock);
|
|
goto unavailable;
|
|
}
|
|
|
|
object = hlist_entry(cookie->backing_objects.first,
|
|
struct fscache_object, cookie_link);
|
|
|
|
fscache_set_store_limit(object, i_size);
|
|
|
|
/* initiate the process of looking up all the objects in the chain
|
|
* (done by fscache_initialise_object()) */
|
|
fscache_enqueue_object(object);
|
|
|
|
spin_unlock(&cookie->lock);
|
|
|
|
/* we may be required to wait for lookup to complete at this point */
|
|
if (!fscache_defer_lookup) {
|
|
_debug("non-deferred lookup %p", &cookie->flags);
|
|
wait_on_bit(&cookie->flags, FSCACHE_COOKIE_LOOKING_UP,
|
|
fscache_wait_bit, TASK_UNINTERRUPTIBLE);
|
|
_debug("complete");
|
|
if (test_bit(FSCACHE_COOKIE_UNAVAILABLE, &cookie->flags))
|
|
goto unavailable;
|
|
}
|
|
|
|
up_read(&fscache_addremove_sem);
|
|
_leave(" = 0 [deferred]");
|
|
return 0;
|
|
|
|
unavailable:
|
|
up_read(&fscache_addremove_sem);
|
|
_leave(" = -ENOBUFS");
|
|
return -ENOBUFS;
|
|
}
|
|
|
|
/*
|
|
* recursively allocate cache object records for a cookie/cache combination
|
|
* - caller must be holding the addremove sem
|
|
*/
|
|
static int fscache_alloc_object(struct fscache_cache *cache,
|
|
struct fscache_cookie *cookie)
|
|
{
|
|
struct fscache_object *object;
|
|
struct hlist_node *_n;
|
|
int ret;
|
|
|
|
_enter("%p,%p{%s}", cache, cookie, cookie->def->name);
|
|
|
|
spin_lock(&cookie->lock);
|
|
hlist_for_each_entry(object, _n, &cookie->backing_objects,
|
|
cookie_link) {
|
|
if (object->cache == cache)
|
|
goto object_already_extant;
|
|
}
|
|
spin_unlock(&cookie->lock);
|
|
|
|
/* ask the cache to allocate an object (we may end up with duplicate
|
|
* objects at this stage, but we sort that out later) */
|
|
fscache_stat(&fscache_n_cop_alloc_object);
|
|
object = cache->ops->alloc_object(cache, cookie);
|
|
fscache_stat_d(&fscache_n_cop_alloc_object);
|
|
if (IS_ERR(object)) {
|
|
fscache_stat(&fscache_n_object_no_alloc);
|
|
ret = PTR_ERR(object);
|
|
goto error;
|
|
}
|
|
|
|
fscache_stat(&fscache_n_object_alloc);
|
|
|
|
object->debug_id = atomic_inc_return(&fscache_object_debug_id);
|
|
|
|
_debug("ALLOC OBJ%x: %s {%lx}",
|
|
object->debug_id, cookie->def->name, object->events);
|
|
|
|
ret = fscache_alloc_object(cache, cookie->parent);
|
|
if (ret < 0)
|
|
goto error_put;
|
|
|
|
/* only attach if we managed to allocate all we needed, otherwise
|
|
* discard the object we just allocated and instead use the one
|
|
* attached to the cookie */
|
|
if (fscache_attach_object(cookie, object) < 0) {
|
|
fscache_stat(&fscache_n_cop_put_object);
|
|
cache->ops->put_object(object);
|
|
fscache_stat_d(&fscache_n_cop_put_object);
|
|
}
|
|
|
|
_leave(" = 0");
|
|
return 0;
|
|
|
|
object_already_extant:
|
|
ret = -ENOBUFS;
|
|
if (object->state >= FSCACHE_OBJECT_DYING) {
|
|
spin_unlock(&cookie->lock);
|
|
goto error;
|
|
}
|
|
spin_unlock(&cookie->lock);
|
|
_leave(" = 0 [found]");
|
|
return 0;
|
|
|
|
error_put:
|
|
fscache_stat(&fscache_n_cop_put_object);
|
|
cache->ops->put_object(object);
|
|
fscache_stat_d(&fscache_n_cop_put_object);
|
|
error:
|
|
_leave(" = %d", ret);
|
|
return ret;
|
|
}
|
|
|
|
/*
|
|
* attach a cache object to a cookie
|
|
*/
|
|
static int fscache_attach_object(struct fscache_cookie *cookie,
|
|
struct fscache_object *object)
|
|
{
|
|
struct fscache_object *p;
|
|
struct fscache_cache *cache = object->cache;
|
|
struct hlist_node *_n;
|
|
int ret;
|
|
|
|
_enter("{%s},{OBJ%x}", cookie->def->name, object->debug_id);
|
|
|
|
spin_lock(&cookie->lock);
|
|
|
|
/* there may be multiple initial creations of this object, but we only
|
|
* want one */
|
|
ret = -EEXIST;
|
|
hlist_for_each_entry(p, _n, &cookie->backing_objects, cookie_link) {
|
|
if (p->cache == object->cache) {
|
|
if (p->state >= FSCACHE_OBJECT_DYING)
|
|
ret = -ENOBUFS;
|
|
goto cant_attach_object;
|
|
}
|
|
}
|
|
|
|
/* pin the parent object */
|
|
spin_lock_nested(&cookie->parent->lock, 1);
|
|
hlist_for_each_entry(p, _n, &cookie->parent->backing_objects,
|
|
cookie_link) {
|
|
if (p->cache == object->cache) {
|
|
if (p->state >= FSCACHE_OBJECT_DYING) {
|
|
ret = -ENOBUFS;
|
|
spin_unlock(&cookie->parent->lock);
|
|
goto cant_attach_object;
|
|
}
|
|
object->parent = p;
|
|
spin_lock(&p->lock);
|
|
p->n_children++;
|
|
spin_unlock(&p->lock);
|
|
break;
|
|
}
|
|
}
|
|
spin_unlock(&cookie->parent->lock);
|
|
|
|
/* attach to the cache's object list */
|
|
if (list_empty(&object->cache_link)) {
|
|
spin_lock(&cache->object_list_lock);
|
|
list_add(&object->cache_link, &cache->object_list);
|
|
spin_unlock(&cache->object_list_lock);
|
|
}
|
|
|
|
/* attach to the cookie */
|
|
object->cookie = cookie;
|
|
atomic_inc(&cookie->usage);
|
|
hlist_add_head(&object->cookie_link, &cookie->backing_objects);
|
|
|
|
fscache_objlist_add(object);
|
|
ret = 0;
|
|
|
|
cant_attach_object:
|
|
spin_unlock(&cookie->lock);
|
|
_leave(" = %d", ret);
|
|
return ret;
|
|
}
|
|
|
|
/*
|
|
* update the index entries backing a cookie
|
|
*/
|
|
void __fscache_update_cookie(struct fscache_cookie *cookie)
|
|
{
|
|
struct fscache_object *object;
|
|
struct hlist_node *_p;
|
|
|
|
fscache_stat(&fscache_n_updates);
|
|
|
|
if (!cookie) {
|
|
fscache_stat(&fscache_n_updates_null);
|
|
_leave(" [no cookie]");
|
|
return;
|
|
}
|
|
|
|
_enter("{%s}", cookie->def->name);
|
|
|
|
BUG_ON(!cookie->def->get_aux);
|
|
|
|
spin_lock(&cookie->lock);
|
|
|
|
/* update the index entry on disk in each cache backing this cookie */
|
|
hlist_for_each_entry(object, _p,
|
|
&cookie->backing_objects, cookie_link) {
|
|
fscache_raise_event(object, FSCACHE_OBJECT_EV_UPDATE);
|
|
}
|
|
|
|
spin_unlock(&cookie->lock);
|
|
_leave("");
|
|
}
|
|
EXPORT_SYMBOL(__fscache_update_cookie);
|
|
|
|
/*
|
|
* release a cookie back to the cache
|
|
* - the object will be marked as recyclable on disk if retire is true
|
|
* - all dependents of this cookie must have already been unregistered
|
|
* (indices/files/pages)
|
|
*/
|
|
void __fscache_relinquish_cookie(struct fscache_cookie *cookie, int retire)
|
|
{
|
|
struct fscache_cache *cache;
|
|
struct fscache_object *object;
|
|
unsigned long event;
|
|
|
|
fscache_stat(&fscache_n_relinquishes);
|
|
if (retire)
|
|
fscache_stat(&fscache_n_relinquishes_retire);
|
|
|
|
if (!cookie) {
|
|
fscache_stat(&fscache_n_relinquishes_null);
|
|
_leave(" [no cookie]");
|
|
return;
|
|
}
|
|
|
|
_enter("%p{%s,%p},%d",
|
|
cookie, cookie->def->name, cookie->netfs_data, retire);
|
|
|
|
if (atomic_read(&cookie->n_children) != 0) {
|
|
printk(KERN_ERR "FS-Cache: Cookie '%s' still has children\n",
|
|
cookie->def->name);
|
|
BUG();
|
|
}
|
|
|
|
/* wait for the cookie to finish being instantiated (or to fail) */
|
|
if (test_bit(FSCACHE_COOKIE_CREATING, &cookie->flags)) {
|
|
fscache_stat(&fscache_n_relinquishes_waitcrt);
|
|
wait_on_bit(&cookie->flags, FSCACHE_COOKIE_CREATING,
|
|
fscache_wait_bit, TASK_UNINTERRUPTIBLE);
|
|
}
|
|
|
|
event = retire ? FSCACHE_OBJECT_EV_RETIRE : FSCACHE_OBJECT_EV_RELEASE;
|
|
|
|
spin_lock(&cookie->lock);
|
|
|
|
/* break links with all the active objects */
|
|
while (!hlist_empty(&cookie->backing_objects)) {
|
|
object = hlist_entry(cookie->backing_objects.first,
|
|
struct fscache_object,
|
|
cookie_link);
|
|
|
|
_debug("RELEASE OBJ%x", object->debug_id);
|
|
|
|
/* detach each cache object from the object cookie */
|
|
spin_lock(&object->lock);
|
|
hlist_del_init(&object->cookie_link);
|
|
|
|
cache = object->cache;
|
|
object->cookie = NULL;
|
|
fscache_raise_event(object, event);
|
|
spin_unlock(&object->lock);
|
|
|
|
if (atomic_dec_and_test(&cookie->usage))
|
|
/* the cookie refcount shouldn't be reduced to 0 yet */
|
|
BUG();
|
|
}
|
|
|
|
/* detach pointers back to the netfs */
|
|
cookie->netfs_data = NULL;
|
|
cookie->def = NULL;
|
|
|
|
spin_unlock(&cookie->lock);
|
|
|
|
if (cookie->parent) {
|
|
ASSERTCMP(atomic_read(&cookie->parent->usage), >, 0);
|
|
ASSERTCMP(atomic_read(&cookie->parent->n_children), >, 0);
|
|
atomic_dec(&cookie->parent->n_children);
|
|
}
|
|
|
|
/* finally dispose of the cookie */
|
|
ASSERTCMP(atomic_read(&cookie->usage), >, 0);
|
|
fscache_cookie_put(cookie);
|
|
|
|
_leave("");
|
|
}
|
|
EXPORT_SYMBOL(__fscache_relinquish_cookie);
|
|
|
|
/*
|
|
* destroy a cookie
|
|
*/
|
|
void __fscache_cookie_put(struct fscache_cookie *cookie)
|
|
{
|
|
struct fscache_cookie *parent;
|
|
|
|
_enter("%p", cookie);
|
|
|
|
for (;;) {
|
|
_debug("FREE COOKIE %p", cookie);
|
|
parent = cookie->parent;
|
|
BUG_ON(!hlist_empty(&cookie->backing_objects));
|
|
kmem_cache_free(fscache_cookie_jar, cookie);
|
|
|
|
if (!parent)
|
|
break;
|
|
|
|
cookie = parent;
|
|
BUG_ON(atomic_read(&cookie->usage) <= 0);
|
|
if (!atomic_dec_and_test(&cookie->usage))
|
|
break;
|
|
}
|
|
|
|
_leave("");
|
|
}
|