[Feature] add GA346 baseline version
Change-Id: Ic62933698569507dcf98240cdf5d9931ae34348f
diff --git a/src/kernel/linux/v4.19/fs/fscache/cookie.c b/src/kernel/linux/v4.19/fs/fscache/cookie.c
new file mode 100644
index 0000000..c550512
--- /dev/null
+++ b/src/kernel/linux/v4.19/fs/fscache/cookie.c
@@ -0,0 +1,964 @@
+/* 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);
+
+#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)
+{
+ unsigned long long h;
+ u32 *buf;
+ int bufs;
+ int i;
+
+ 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);
+
+ /* Calculate a hash and combine this with the length in the first word
+ * or first half word
+ */
+ h = (unsigned long)cookie->parent;
+ h += index_key_len + cookie->type;
+
+ for (i = 0; i < bufs; i++)
+ h += buf[i];
+
+ cookie->key_hash = h ^ (h >> 32);
+ 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);