+++ /dev/null
-// 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 LIST_HEAD(fscache_cookies);
-static DEFINE_RWLOCK(fscache_cookies_lock);
-
-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 fscache_object *object;
- struct hlist_node *o;
- const u8 *k;
- unsigned loop;
-
- pr_err("%c-cookie c=%08x [p=%08x fl=%lx nc=%u na=%u]\n",
- prefix,
- cookie->debug_id,
- cookie->parent ? cookie->parent->debug_id : 0,
- cookie->flags,
- atomic_read(&cookie->n_children),
- atomic_read(&cookie->n_active));
- pr_err("%c-cookie d=%p{%s} n=%p\n",
- prefix,
- cookie->def,
- cookie->def ? cookie->def->name : "?",
- cookie->netfs_data);
-
- o = READ_ONCE(cookie->backing_objects.first);
- if (o) {
- object = hlist_entry(o, struct fscache_object, cookie_link);
- pr_err("%c-cookie o=%u\n", prefix, object->debug_id);
- }
-
- 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));
- write_lock(&fscache_cookies_lock);
- list_del(&cookie->proc_link);
- write_unlock(&fscache_cookies_lock);
- 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);
-}
-
-static atomic_t fscache_cookie_debug_id = ATOMIC_INIT(1);
-
-/*
- * 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;
- }
-
- refcount_set(&cookie->ref, 1);
- atomic_set(&cookie->n_children, 0);
- cookie->debug_id = atomic_inc_return(&fscache_cookie_debug_id);
-
- /* 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);
-
- write_lock(&fscache_cookies_lock);
- list_add_tail(&cookie->proc_link, &fscache_cookies);
- write_unlock(&fscache_cookies_lock);
- 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->debug_id, refcount_read(&cursor->ref),
- fscache_cookie_collision);
- 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->debug_id, 1,
- fscache_cookie_discard);
- 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("%x", cookie->debug_id);
-
- 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) {
- wait_on_bit(&cookie->flags, FSCACHE_COOKIE_LOOKING_UP,
- TASK_UNINTERRUPTIBLE);
- 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("%s,%x{%s}", cache->tag->name, cookie->debug_id, 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);
- 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("%x", cookie->debug_id);
-
- 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("%x,%u", cookie->debug_id, 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("%x{%s,%d},%d",
- cookie->debug_id, cookie->def->name,
- 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(refcount_read(&cookie->parent->ref), >, 0);
- ASSERTCMP(atomic_read(&cookie->parent->n_children), >, 0);
- atomic_dec(&cookie->parent->n_children);
- }
-
- /* Dispose of the netfs's link to the cookie */
- 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 ref;
-
- _enter("%x", cookie->debug_id);
-
- do {
- unsigned int cookie_debug_id = cookie->debug_id;
- bool zero = __refcount_dec_and_test(&cookie->ref, &ref);
-
- trace_fscache_cookie(cookie_debug_id, ref - 1, where);
- if (!zero)
- return;
-
- parent = cookie->parent;
- fscache_unhash_cookie(cookie);
- fscache_free_cookie(cookie);
-
- cookie = parent;
- where = fscache_cookie_put_parent;
- } while (cookie);
-
- _leave("");
-}
-
-/*
- * Get a reference to a cookie.
- */
-struct fscache_cookie *fscache_cookie_get(struct fscache_cookie *cookie,
- enum fscache_cookie_trace where)
-{
- int ref;
-
- __refcount_inc(&cookie->ref, &ref);
- trace_fscache_cookie(cookie->debug_id, ref + 1, where);
- return cookie;
-}
-
-/*
- * 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);
-
-/*
- * Generate a list of extant cookies in /proc/fs/fscache/cookies
- */
-static int fscache_cookies_seq_show(struct seq_file *m, void *v)
-{
- struct fscache_cookie *cookie;
- unsigned int keylen = 0, auxlen = 0;
- char _type[3], *type;
- u8 *p;
-
- if (v == &fscache_cookies) {
- seq_puts(m,
- "COOKIE PARENT USAGE CHILD ACT TY FL DEF NETFS_DATA\n"
- "======== ======== ===== ===== === == === ================ ==========\n"
- );
- return 0;
- }
-
- cookie = list_entry(v, struct fscache_cookie, proc_link);
-
- switch (cookie->type) {
- case 0:
- type = "IX";
- break;
- case 1:
- type = "DT";
- break;
- default:
- snprintf(_type, sizeof(_type), "%02u",
- cookie->type);
- type = _type;
- break;
- }
-
- seq_printf(m,
- "%08x %08x %5u %5u %3u %s %03lx %-16s %px",
- cookie->debug_id,
- cookie->parent ? cookie->parent->debug_id : 0,
- refcount_read(&cookie->ref),
- atomic_read(&cookie->n_children),
- atomic_read(&cookie->n_active),
- type,
- cookie->flags,
- cookie->def->name,
- cookie->netfs_data);
-
- keylen = cookie->key_len;
- auxlen = cookie->aux_len;
-
- if (keylen > 0 || auxlen > 0) {
- seq_puts(m, " ");
- p = keylen <= sizeof(cookie->inline_key) ?
- cookie->inline_key : cookie->key;
- for (; keylen > 0; keylen--)
- seq_printf(m, "%02x", *p++);
- if (auxlen > 0) {
- seq_puts(m, ", ");
- p = auxlen <= sizeof(cookie->inline_aux) ?
- cookie->inline_aux : cookie->aux;
- for (; auxlen > 0; auxlen--)
- seq_printf(m, "%02x", *p++);
- }
- }
-
- seq_puts(m, "\n");
- return 0;
-}
-
-static void *fscache_cookies_seq_start(struct seq_file *m, loff_t *_pos)
- __acquires(fscache_cookies_lock)
-{
- read_lock(&fscache_cookies_lock);
- return seq_list_start_head(&fscache_cookies, *_pos);
-}
-
-static void *fscache_cookies_seq_next(struct seq_file *m, void *v, loff_t *_pos)
-{
- return seq_list_next(v, &fscache_cookies, _pos);
-}
-
-static void fscache_cookies_seq_stop(struct seq_file *m, void *v)
- __releases(rcu)
-{
- read_unlock(&fscache_cookies_lock);
-}
-
-
-const struct seq_operations fscache_cookies_seq_ops = {
- .start = fscache_cookies_seq_start,
- .next = fscache_cookies_seq_next,
- .stop = fscache_cookies_seq_stop,
- .show = fscache_cookies_seq_show,
-};
projects / linux-2.6-microblaze.git / blobdiff