// SPDX-License-Identifier: GPL-2.0-or-later
|
/* netfs cookie management
|
*
|
* Copyright (C) 2004-2007 Red Hat, Inc. All Rights Reserved.
|
* Written by David Howells (dhowells@redhat.com)
|
*
|
* See Documentation/filesystems/caching/netfs-api.rst 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);
|
|
#define fscache_cookie_hash_shift 15
|
static struct hlist_bl_head fscache_cookie_hash[1 << fscache_cookie_hash_shift];
|
|
static int fscache_acquire_non_index_cookie(struct fscache_cookie *cookie,
|
loff_t object_size);
|
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);
|
|
static void fscache_print_cookie(struct fscache_cookie *cookie, char prefix)
|
{
|
struct hlist_node *object;
|
const u8 *k;
|
unsigned loop;
|
|
pr_err("%c-cookie c=%p [p=%p fl=%lx nc=%u na=%u]\n",
|
prefix, cookie, cookie->parent, cookie->flags,
|
atomic_read(&cookie->n_children),
|
atomic_read(&cookie->n_active));
|
pr_err("%c-cookie d=%p n=%p\n",
|
prefix, cookie->def, cookie->netfs_data);
|
|
object = READ_ONCE(cookie->backing_objects.first);
|
if (object)
|
pr_err("%c-cookie o=%p\n",
|
prefix, hlist_entry(object, struct fscache_object, cookie_link));
|
|
pr_err("%c-key=[%u] '", prefix, cookie->key_len);
|
k = (cookie->key_len <= sizeof(cookie->inline_key)) ?
|
cookie->inline_key : cookie->key;
|
for (loop = 0; loop < cookie->key_len; loop++)
|
pr_cont("%02x", k[loop]);
|
pr_cont("'\n");
|
}
|
|
void fscache_free_cookie(struct fscache_cookie *cookie)
|
{
|
if (cookie) {
|
BUG_ON(!hlist_empty(&cookie->backing_objects));
|
if (cookie->aux_len > sizeof(cookie->inline_aux))
|
kfree(cookie->aux);
|
if (cookie->key_len > sizeof(cookie->inline_key))
|
kfree(cookie->key);
|
kmem_cache_free(fscache_cookie_jar, cookie);
|
}
|
}
|
|
/*
|
* Set the index key in a cookie. The cookie struct has space for a 16-byte
|
* key plus length and hash, but if that's not big enough, it's instead a
|
* pointer to a buffer containing 3 bytes of hash, 1 byte of length and then
|
* the key data.
|
*/
|
static int fscache_set_key(struct fscache_cookie *cookie,
|
const void *index_key, size_t index_key_len)
|
{
|
u32 *buf;
|
int bufs;
|
|
bufs = DIV_ROUND_UP(index_key_len, sizeof(*buf));
|
|
if (index_key_len > sizeof(cookie->inline_key)) {
|
buf = kcalloc(bufs, sizeof(*buf), GFP_KERNEL);
|
if (!buf)
|
return -ENOMEM;
|
cookie->key = buf;
|
} else {
|
buf = (u32 *)cookie->inline_key;
|
}
|
|
memcpy(buf, index_key, index_key_len);
|
cookie->key_hash = fscache_hash(0, buf, bufs);
|
return 0;
|
}
|
|
static long fscache_compare_cookie(const struct fscache_cookie *a,
|
const struct fscache_cookie *b)
|
{
|
const void *ka, *kb;
|
|
if (a->key_hash != b->key_hash)
|
return (long)a->key_hash - (long)b->key_hash;
|
if (a->parent != b->parent)
|
return (long)a->parent - (long)b->parent;
|
if (a->key_len != b->key_len)
|
return (long)a->key_len - (long)b->key_len;
|
if (a->type != b->type)
|
return (long)a->type - (long)b->type;
|
|
if (a->key_len <= sizeof(a->inline_key)) {
|
ka = &a->inline_key;
|
kb = &b->inline_key;
|
} else {
|
ka = a->key;
|
kb = b->key;
|
}
|
return memcmp(ka, kb, a->key_len);
|
}
|
|
/*
|
* Allocate a cookie.
|
*/
|
struct fscache_cookie *fscache_alloc_cookie(
|
struct fscache_cookie *parent,
|
const struct fscache_cookie_def *def,
|
const void *index_key, size_t index_key_len,
|
const void *aux_data, size_t aux_data_len,
|
void *netfs_data,
|
loff_t object_size)
|
{
|
struct fscache_cookie *cookie;
|
|
/* allocate and initialise a cookie */
|
cookie = kmem_cache_zalloc(fscache_cookie_jar, GFP_KERNEL);
|
if (!cookie)
|
return NULL;
|
|
cookie->key_len = index_key_len;
|
cookie->aux_len = aux_data_len;
|
|
if (fscache_set_key(cookie, index_key, index_key_len) < 0)
|
goto nomem;
|
|
if (cookie->aux_len <= sizeof(cookie->inline_aux)) {
|
memcpy(cookie->inline_aux, aux_data, cookie->aux_len);
|
} else {
|
cookie->aux = kmemdup(aux_data, cookie->aux_len, GFP_KERNEL);
|
if (!cookie->aux)
|
goto nomem;
|
}
|
|
atomic_set(&cookie->usage, 1);
|
atomic_set(&cookie->n_children, 0);
|
|
/* We keep the active count elevated until relinquishment to prevent an
|
* attempt to wake up every time the object operations queue quiesces.
|
*/
|
atomic_set(&cookie->n_active, 1);
|
|
cookie->def = def;
|
cookie->parent = parent;
|
cookie->netfs_data = netfs_data;
|
cookie->flags = (1 << FSCACHE_COOKIE_NO_DATA_YET);
|
cookie->type = def->type;
|
spin_lock_init(&cookie->lock);
|
spin_lock_init(&cookie->stores_lock);
|
INIT_HLIST_HEAD(&cookie->backing_objects);
|
|
/* 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_DIRECT_RECLAIM);
|
return cookie;
|
|
nomem:
|
fscache_free_cookie(cookie);
|
return NULL;
|
}
|
|
/*
|
* Attempt to insert the new cookie into the hash. If there's a collision, we
|
* return the old cookie if it's not in use and an error otherwise.
|
*/
|
struct fscache_cookie *fscache_hash_cookie(struct fscache_cookie *candidate)
|
{
|
struct fscache_cookie *cursor;
|
struct hlist_bl_head *h;
|
struct hlist_bl_node *p;
|
unsigned int bucket;
|
|
bucket = candidate->key_hash & (ARRAY_SIZE(fscache_cookie_hash) - 1);
|
h = &fscache_cookie_hash[bucket];
|
|
hlist_bl_lock(h);
|
hlist_bl_for_each_entry(cursor, p, h, hash_link) {
|
if (fscache_compare_cookie(candidate, cursor) == 0)
|
goto collision;
|
}
|
|
__set_bit(FSCACHE_COOKIE_ACQUIRED, &candidate->flags);
|
fscache_cookie_get(candidate->parent, fscache_cookie_get_acquire_parent);
|
atomic_inc(&candidate->parent->n_children);
|
hlist_bl_add_head(&candidate->hash_link, h);
|
hlist_bl_unlock(h);
|
return candidate;
|
|
collision:
|
if (test_and_set_bit(FSCACHE_COOKIE_ACQUIRED, &cursor->flags)) {
|
trace_fscache_cookie(cursor, fscache_cookie_collision,
|
atomic_read(&cursor->usage));
|
pr_err("Duplicate cookie detected\n");
|
fscache_print_cookie(cursor, 'O');
|
fscache_print_cookie(candidate, 'N');
|
hlist_bl_unlock(h);
|
return NULL;
|
}
|
|
fscache_cookie_get(cursor, fscache_cookie_get_reacquire);
|
hlist_bl_unlock(h);
|
return cursor;
|
}
|
|
/*
|
* 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,
|
const void *index_key, size_t index_key_len,
|
const void *aux_data, size_t aux_data_len,
|
void *netfs_data,
|
loff_t object_size,
|
bool enable)
|
{
|
struct fscache_cookie *candidate, *cookie;
|
|
BUG_ON(!def);
|
|
_enter("{%s},{%s},%p,%u",
|
parent ? (char *) parent->def->name : "<no-parent>",
|
def->name, netfs_data, enable);
|
|
if (!index_key || !index_key_len || index_key_len > 255 || aux_data_len > 255)
|
return NULL;
|
if (!aux_data || !aux_data_len) {
|
aux_data = NULL;
|
aux_data_len = 0;
|
}
|
|
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->name[0]);
|
|
BUG_ON(def->type == FSCACHE_COOKIE_TYPE_INDEX &&
|
parent->type != FSCACHE_COOKIE_TYPE_INDEX);
|
|
candidate = fscache_alloc_cookie(parent, def,
|
index_key, index_key_len,
|
aux_data, aux_data_len,
|
netfs_data, object_size);
|
if (!candidate) {
|
fscache_stat(&fscache_n_acquires_oom);
|
_leave(" [ENOMEM]");
|
return NULL;
|
}
|
|
cookie = fscache_hash_cookie(candidate);
|
if (!cookie) {
|
trace_fscache_cookie(candidate, fscache_cookie_discard, 1);
|
goto out;
|
}
|
|
if (cookie == candidate)
|
candidate = NULL;
|
|
switch (cookie->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;
|
}
|
|
trace_fscache_acquire(cookie);
|
|
if (enable) {
|
/* 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->type != FSCACHE_COOKIE_TYPE_INDEX) {
|
if (fscache_acquire_non_index_cookie(cookie, object_size) == 0) {
|
set_bit(FSCACHE_COOKIE_ENABLED, &cookie->flags);
|
} else {
|
atomic_dec(&parent->n_children);
|
fscache_cookie_put(cookie,
|
fscache_cookie_put_acquire_nobufs);
|
fscache_stat(&fscache_n_acquires_nobufs);
|
_leave(" = NULL");
|
return NULL;
|
}
|
} else {
|
set_bit(FSCACHE_COOKIE_ENABLED, &cookie->flags);
|
}
|
}
|
|
fscache_stat(&fscache_n_acquires_ok);
|
|
out:
|
fscache_free_cookie(candidate);
|
return cookie;
|
}
|
EXPORT_SYMBOL(__fscache_acquire_cookie);
|
|
/*
|
* Enable a cookie to permit it to accept new operations.
|
*/
|
void __fscache_enable_cookie(struct fscache_cookie *cookie,
|
const void *aux_data,
|
loff_t object_size,
|
bool (*can_enable)(void *data),
|
void *data)
|
{
|
_enter("%p", cookie);
|
|
trace_fscache_enable(cookie);
|
|
wait_on_bit_lock(&cookie->flags, FSCACHE_COOKIE_ENABLEMENT_LOCK,
|
TASK_UNINTERRUPTIBLE);
|
|
fscache_update_aux(cookie, aux_data);
|
|
if (test_bit(FSCACHE_COOKIE_ENABLED, &cookie->flags))
|
goto out_unlock;
|
|
if (can_enable && !can_enable(data)) {
|
/* The netfs decided it didn't want to enable after all */
|
} else if (cookie->type != FSCACHE_COOKIE_TYPE_INDEX) {
|
/* Wait for outstanding disablement to complete */
|
__fscache_wait_on_invalidate(cookie);
|
|
if (fscache_acquire_non_index_cookie(cookie, object_size) == 0)
|
set_bit(FSCACHE_COOKIE_ENABLED, &cookie->flags);
|
} else {
|
set_bit(FSCACHE_COOKIE_ENABLED, &cookie->flags);
|
}
|
|
out_unlock:
|
clear_bit_unlock(FSCACHE_COOKIE_ENABLEMENT_LOCK, &cookie->flags);
|
wake_up_bit(&cookie->flags, FSCACHE_COOKIE_ENABLEMENT_LOCK);
|
}
|
EXPORT_SYMBOL(__fscache_enable_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,
|
loff_t object_size)
|
{
|
struct fscache_object *object;
|
struct fscache_cache *cache;
|
int ret;
|
|
_enter("");
|
|
set_bit(FSCACHE_COOKIE_UNAVAILABLE, &cookie->flags);
|
|
/* 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);
|
|
set_bit(FSCACHE_COOKIE_LOOKING_UP, &cookie->flags);
|
|
/* 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;
|
}
|
|
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, object_size);
|
|
/* initiate the process of looking up all the objects in the chain
|
* (done by fscache_initialise_object()) */
|
fscache_raise_event(object, FSCACHE_OBJECT_EV_NEW_CHILD);
|
|
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,
|
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;
|
int ret;
|
|
_enter("%p,%p{%s}", cache, cookie, cookie->def->name);
|
|
spin_lock(&cookie->lock);
|
hlist_for_each_entry(object, &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;
|
}
|
|
ASSERTCMP(object->cookie, ==, cookie);
|
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_obj_put_attach_fail);
|
fscache_stat_d(&fscache_n_cop_put_object);
|
}
|
|
_leave(" = 0");
|
return 0;
|
|
object_already_extant:
|
ret = -ENOBUFS;
|
if (fscache_object_is_dying(object) ||
|
fscache_cache_is_broken(object)) {
|
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_obj_put_alloc_fail);
|
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;
|
int ret;
|
|
_enter("{%s},{OBJ%x}", cookie->def->name, object->debug_id);
|
|
ASSERTCMP(object->cookie, ==, cookie);
|
|
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, &cookie->backing_objects, cookie_link) {
|
if (p->cache == object->cache) {
|
if (fscache_object_is_dying(p))
|
ret = -ENOBUFS;
|
goto cant_attach_object;
|
}
|
}
|
|
/* pin the parent object */
|
spin_lock_nested(&cookie->parent->lock, 1);
|
hlist_for_each_entry(p, &cookie->parent->backing_objects,
|
cookie_link) {
|
if (p->cache == object->cache) {
|
if (fscache_object_is_dying(p)) {
|
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. The object already has a ref on it. */
|
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;
|
}
|
|
/*
|
* Invalidate an object. Callable with spinlocks held.
|
*/
|
void __fscache_invalidate(struct fscache_cookie *cookie)
|
{
|
struct fscache_object *object;
|
|
_enter("{%s}", cookie->def->name);
|
|
fscache_stat(&fscache_n_invalidates);
|
|
/* Only permit invalidation of data files. Invalidating an index will
|
* require the caller to release all its attachments to the tree rooted
|
* there, and if it's doing that, it may as well just retire the
|
* cookie.
|
*/
|
ASSERTCMP(cookie->type, ==, FSCACHE_COOKIE_TYPE_DATAFILE);
|
|
/* If there's an object, we tell the object state machine to handle the
|
* invalidation on our behalf, otherwise there's nothing to do.
|
*/
|
if (!hlist_empty(&cookie->backing_objects)) {
|
spin_lock(&cookie->lock);
|
|
if (fscache_cookie_enabled(cookie) &&
|
!hlist_empty(&cookie->backing_objects) &&
|
!test_and_set_bit(FSCACHE_COOKIE_INVALIDATING,
|
&cookie->flags)) {
|
object = hlist_entry(cookie->backing_objects.first,
|
struct fscache_object,
|
cookie_link);
|
if (fscache_object_is_live(object))
|
fscache_raise_event(
|
object, FSCACHE_OBJECT_EV_INVALIDATE);
|
}
|
|
spin_unlock(&cookie->lock);
|
}
|
|
_leave("");
|
}
|
EXPORT_SYMBOL(__fscache_invalidate);
|
|
/*
|
* Wait for object invalidation to complete.
|
*/
|
void __fscache_wait_on_invalidate(struct fscache_cookie *cookie)
|
{
|
_enter("%p", cookie);
|
|
wait_on_bit(&cookie->flags, FSCACHE_COOKIE_INVALIDATING,
|
TASK_UNINTERRUPTIBLE);
|
|
_leave("");
|
}
|
EXPORT_SYMBOL(__fscache_wait_on_invalidate);
|
|
/*
|
* update the index entries backing a cookie
|
*/
|
void __fscache_update_cookie(struct fscache_cookie *cookie, const void *aux_data)
|
{
|
struct fscache_object *object;
|
|
fscache_stat(&fscache_n_updates);
|
|
if (!cookie) {
|
fscache_stat(&fscache_n_updates_null);
|
_leave(" [no cookie]");
|
return;
|
}
|
|
_enter("{%s}", cookie->def->name);
|
|
spin_lock(&cookie->lock);
|
|
fscache_update_aux(cookie, aux_data);
|
|
if (fscache_cookie_enabled(cookie)) {
|
/* update the index entry on disk in each cache backing this
|
* cookie.
|
*/
|
hlist_for_each_entry(object,
|
&cookie->backing_objects, cookie_link) {
|
fscache_raise_event(object, FSCACHE_OBJECT_EV_UPDATE);
|
}
|
}
|
|
spin_unlock(&cookie->lock);
|
_leave("");
|
}
|
EXPORT_SYMBOL(__fscache_update_cookie);
|
|
/*
|
* Disable a cookie to stop it from accepting new requests from the netfs.
|
*/
|
void __fscache_disable_cookie(struct fscache_cookie *cookie,
|
const void *aux_data,
|
bool invalidate)
|
{
|
struct fscache_object *object;
|
bool awaken = false;
|
|
_enter("%p,%u", cookie, invalidate);
|
|
trace_fscache_disable(cookie);
|
|
ASSERTCMP(atomic_read(&cookie->n_active), >, 0);
|
|
if (atomic_read(&cookie->n_children) != 0) {
|
pr_err("Cookie '%s' still has children\n",
|
cookie->def->name);
|
BUG();
|
}
|
|
wait_on_bit_lock(&cookie->flags, FSCACHE_COOKIE_ENABLEMENT_LOCK,
|
TASK_UNINTERRUPTIBLE);
|
|
fscache_update_aux(cookie, aux_data);
|
|
if (!test_and_clear_bit(FSCACHE_COOKIE_ENABLED, &cookie->flags))
|
goto out_unlock_enable;
|
|
/* If the cookie is being invalidated, wait for that to complete first
|
* so that we can reuse the flag.
|
*/
|
__fscache_wait_on_invalidate(cookie);
|
|
/* Dispose of the backing objects */
|
set_bit(FSCACHE_COOKIE_INVALIDATING, &cookie->flags);
|
|
spin_lock(&cookie->lock);
|
if (!hlist_empty(&cookie->backing_objects)) {
|
hlist_for_each_entry(object, &cookie->backing_objects, cookie_link) {
|
if (invalidate)
|
set_bit(FSCACHE_OBJECT_RETIRED, &object->flags);
|
clear_bit(FSCACHE_OBJECT_PENDING_WRITE, &object->flags);
|
fscache_raise_event(object, FSCACHE_OBJECT_EV_KILL);
|
}
|
} else {
|
if (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);
|
|
/* Wait for cessation of activity requiring access to the netfs (when
|
* n_active reaches 0). This makes sure outstanding reads and writes
|
* have completed.
|
*/
|
if (!atomic_dec_and_test(&cookie->n_active)) {
|
wait_var_event(&cookie->n_active,
|
!atomic_read(&cookie->n_active));
|
}
|
|
/* Make sure any pending writes are cancelled. */
|
if (cookie->type != FSCACHE_COOKIE_TYPE_INDEX)
|
fscache_invalidate_writes(cookie);
|
|
/* Reset the cookie state if it wasn't relinquished */
|
if (!test_bit(FSCACHE_COOKIE_RELINQUISHED, &cookie->flags)) {
|
atomic_inc(&cookie->n_active);
|
set_bit(FSCACHE_COOKIE_NO_DATA_YET, &cookie->flags);
|
}
|
|
out_unlock_enable:
|
clear_bit_unlock(FSCACHE_COOKIE_ENABLEMENT_LOCK, &cookie->flags);
|
wake_up_bit(&cookie->flags, FSCACHE_COOKIE_ENABLEMENT_LOCK);
|
_leave("");
|
}
|
EXPORT_SYMBOL(__fscache_disable_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,
|
const void *aux_data,
|
bool retire)
|
{
|
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},%d",
|
cookie, cookie->def->name, cookie->netfs_data,
|
atomic_read(&cookie->n_active), retire);
|
|
trace_fscache_relinquish(cookie, retire);
|
|
/* No further netfs-accessing operations on this cookie permitted */
|
if (test_and_set_bit(FSCACHE_COOKIE_RELINQUISHED, &cookie->flags))
|
BUG();
|
|
__fscache_disable_cookie(cookie, aux_data, retire);
|
|
/* Clear pointers back to the netfs */
|
cookie->netfs_data = NULL;
|
cookie->def = NULL;
|
BUG_ON(!radix_tree_empty(&cookie->stores));
|
|
if (cookie->parent) {
|
ASSERTCMP(atomic_read(&cookie->parent->usage), >, 0);
|
ASSERTCMP(atomic_read(&cookie->parent->n_children), >, 0);
|
atomic_dec(&cookie->parent->n_children);
|
}
|
|
/* Dispose of the netfs's link to the cookie */
|
ASSERTCMP(atomic_read(&cookie->usage), >, 0);
|
fscache_cookie_put(cookie, fscache_cookie_put_relinquish);
|
|
_leave("");
|
}
|
EXPORT_SYMBOL(__fscache_relinquish_cookie);
|
|
/*
|
* Remove a cookie from the hash table.
|
*/
|
static void fscache_unhash_cookie(struct fscache_cookie *cookie)
|
{
|
struct hlist_bl_head *h;
|
unsigned int bucket;
|
|
bucket = cookie->key_hash & (ARRAY_SIZE(fscache_cookie_hash) - 1);
|
h = &fscache_cookie_hash[bucket];
|
|
hlist_bl_lock(h);
|
hlist_bl_del(&cookie->hash_link);
|
hlist_bl_unlock(h);
|
}
|
|
/*
|
* Drop a reference to a cookie.
|
*/
|
void fscache_cookie_put(struct fscache_cookie *cookie,
|
enum fscache_cookie_trace where)
|
{
|
struct fscache_cookie *parent;
|
int usage;
|
|
_enter("%p", cookie);
|
|
do {
|
usage = atomic_dec_return(&cookie->usage);
|
trace_fscache_cookie(cookie, where, usage);
|
|
if (usage > 0)
|
return;
|
BUG_ON(usage < 0);
|
|
parent = cookie->parent;
|
fscache_unhash_cookie(cookie);
|
fscache_free_cookie(cookie);
|
|
cookie = parent;
|
where = fscache_cookie_put_parent;
|
} while (cookie);
|
|
_leave("");
|
}
|
|
/*
|
* check the consistency between the netfs inode and the backing cache
|
*
|
* NOTE: it only serves no-index type
|
*/
|
int __fscache_check_consistency(struct fscache_cookie *cookie,
|
const void *aux_data)
|
{
|
struct fscache_operation *op;
|
struct fscache_object *object;
|
bool wake_cookie = false;
|
int ret;
|
|
_enter("%p,", cookie);
|
|
ASSERTCMP(cookie->type, ==, FSCACHE_COOKIE_TYPE_DATAFILE);
|
|
if (fscache_wait_for_deferred_lookup(cookie) < 0)
|
return -ERESTARTSYS;
|
|
if (hlist_empty(&cookie->backing_objects))
|
return 0;
|
|
op = kzalloc(sizeof(*op), GFP_NOIO | __GFP_NOMEMALLOC | __GFP_NORETRY);
|
if (!op)
|
return -ENOMEM;
|
|
fscache_operation_init(cookie, op, NULL, NULL, NULL);
|
op->flags = FSCACHE_OP_MYTHREAD |
|
(1 << FSCACHE_OP_WAITING) |
|
(1 << FSCACHE_OP_UNUSE_COOKIE);
|
trace_fscache_page_op(cookie, NULL, op, fscache_page_op_check_consistency);
|
|
spin_lock(&cookie->lock);
|
|
fscache_update_aux(cookie, aux_data);
|
|
if (!fscache_cookie_enabled(cookie) ||
|
hlist_empty(&cookie->backing_objects))
|
goto inconsistent;
|
object = hlist_entry(cookie->backing_objects.first,
|
struct fscache_object, cookie_link);
|
if (test_bit(FSCACHE_IOERROR, &object->cache->flags))
|
goto inconsistent;
|
|
op->debug_id = atomic_inc_return(&fscache_op_debug_id);
|
|
__fscache_use_cookie(cookie);
|
if (fscache_submit_op(object, op) < 0)
|
goto submit_failed;
|
|
/* the work queue now carries its own ref on the object */
|
spin_unlock(&cookie->lock);
|
|
ret = fscache_wait_for_operation_activation(object, op, NULL, NULL);
|
if (ret == 0) {
|
/* ask the cache to honour the operation */
|
ret = object->cache->ops->check_consistency(op);
|
fscache_op_complete(op, false);
|
} else if (ret == -ENOBUFS) {
|
ret = 0;
|
}
|
|
fscache_put_operation(op);
|
_leave(" = %d", ret);
|
return ret;
|
|
submit_failed:
|
wake_cookie = __fscache_unuse_cookie(cookie);
|
inconsistent:
|
spin_unlock(&cookie->lock);
|
if (wake_cookie)
|
__fscache_wake_unused_cookie(cookie);
|
kfree(op);
|
_leave(" = -ESTALE");
|
return -ESTALE;
|
}
|
EXPORT_SYMBOL(__fscache_check_consistency);
|
