diff options
Diffstat (limited to 'fs/fscache/cookie.c')
| -rw-r--r-- | fs/fscache/cookie.c | 1071 |
1 files changed, 0 insertions, 1071 deletions
diff --git a/fs/fscache/cookie.c b/fs/fscache/cookie.c deleted file mode 100644 index cd42be646ed3..000000000000 --- a/fs/fscache/cookie.c +++ /dev/null @@ -1,1071 +0,0 @@ -// 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, -}; 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