2 /* FS-Cache cache handling
8 #define FSCACHE_DEBUG_LEVEL CACHE
21  * look up a cache tag
67  * release a reference to a cache tag
86  * select a cache in which to store an object
87  * - the cache addremove semaphore must be at least read-locked by the caller
95 	struct fscache_cache *cache;  in fscache_select_cache_for_object()  local
100 		_leave(" = NULL [no cache]");  in fscache_select_cache_for_object()
104 	/* we check the parent to determine the cache to use */  in fscache_select_cache_for_object()
108 	 * cache */  in fscache_select_cache_for_object()
113 		cache = object->cache;  in fscache_select_cache_for_object()
115 		    test_bit(FSCACHE_IOERROR, &cache->flags))  in fscache_select_cache_for_object()
116 			cache = NULL;  in fscache_select_cache_for_object()
119 		_leave(" = %p [parent]", cache);  in fscache_select_cache_for_object()
120 		return cache;  in fscache_select_cache_for_object()
147 	if (!tag->cache) {  in fscache_select_cache_for_object()
152 	if (test_bit(FSCACHE_IOERROR, &tag->cache->flags))  in fscache_select_cache_for_object()
155 	_leave(" = %p [specific]", tag->cache);  in fscache_select_cache_for_object()
156 	return tag->cache;  in fscache_select_cache_for_object()
159 	/* netfs has no preference - just select first cache */  in fscache_select_cache_for_object()
160 	cache = list_entry(fscache_cache_list.next,  in fscache_select_cache_for_object()
162 	_leave(" = %p [first]", cache);  in fscache_select_cache_for_object()
163 	return cache;  in fscache_select_cache_for_object()
167  * fscache_init_cache - Initialise a cache record
168  * @cache: The cache record to be initialised
169  * @ops: The cache operations to be installed in that record
173  * Initialise a record of a cache and fill in the name.
178 void fscache_init_cache(struct fscache_cache *cache,  in fscache_init_cache()  argument
185 	memset(cache, 0, sizeof(*cache));  in fscache_init_cache()
187 	cache->ops = ops;  in fscache_init_cache()
190 	vsnprintf(cache->identifier, sizeof(cache->identifier), idfmt, va);  in fscache_init_cache()
193 	INIT_WORK(&cache->op_gc, fscache_operation_gc);  in fscache_init_cache()
194 	INIT_LIST_HEAD(&cache->link);  in fscache_init_cache()
195 	INIT_LIST_HEAD(&cache->object_list);  in fscache_init_cache()
196 	INIT_LIST_HEAD(&cache->op_gc_list);  in fscache_init_cache()
197 	spin_lock_init(&cache->object_list_lock);  in fscache_init_cache()
198 	spin_lock_init(&cache->op_gc_list_lock);  in fscache_init_cache()
203  * fscache_add_cache - Declare a cache as being open for business
204  * @cache: The record describing the cache
205  * @ifsdef: The record of the cache object describing the top-level index
206  * @tagname: The tag describing this cache
208  * Add a cache to the system, making it available for netfs's to use.
213 int fscache_add_cache(struct fscache_cache *cache,  in fscache_add_cache()  argument
220 	BUG_ON(!cache->ops);  in fscache_add_cache()
223 	cache->flags = 0;  in fscache_add_cache()
230 		tagname = cache->identifier;  in fscache_add_cache()
234 	_enter("{%s.%s},,%s", cache->ops->name, cache->identifier, tagname);  in fscache_add_cache()
236 	/* we use the cache tag to uniquely identify caches */  in fscache_add_cache()
244 	cache->kobj = kobject_create_and_add(tagname, fscache_root);  in fscache_add_cache()
245 	if (!cache->kobj)  in fscache_add_cache()
248 	ifsdef->cache = cache;  in fscache_add_cache()
249 	cache->fsdef = ifsdef;  in fscache_add_cache()
253 	tag->cache = cache;  in fscache_add_cache()
254 	cache->tag = tag;  in fscache_add_cache()
256 	/* add the cache to the list */  in fscache_add_cache()
257 	list_add(&cache->link, &fscache_cache_list);  in fscache_add_cache()
259 	/* add the cache's netfs definition index object to the cache's  in fscache_add_cache()
261 	spin_lock(&cache->object_list_lock);  in fscache_add_cache()
262 	list_add_tail(&ifsdef->cache_link, &cache->object_list);  in fscache_add_cache()
263 	spin_unlock(&cache->object_list_lock);  in fscache_add_cache()
266 	/* add the cache's netfs definition index object to the top level index  in fscache_add_cache()
279 	pr_notice("Cache \"%s\" added (type %s)\n",  in fscache_add_cache()
280 		  cache->tag->name, cache->ops->name);  in fscache_add_cache()
281 	kobject_uevent(cache->kobj, KOBJ_ADD);  in fscache_add_cache()
283 	_leave(" = 0 [%s]", cache->identifier);  in fscache_add_cache()
287 	pr_err("Cache tag '%s' already in use\n", tagname);  in fscache_add_cache()
304  * fscache_io_error - Note a cache I/O error
305  * @cache: The record describing the cache
307  * Note that an I/O error occurred in a cache and that it should no longer be
313 void fscache_io_error(struct fscache_cache *cache)  in fscache_io_error()  argument
315 	if (!test_and_set_bit(FSCACHE_IOERROR, &cache->flags))  in fscache_io_error()
316 		pr_err("Cache '%s' stopped due to I/O error\n",  in fscache_io_error()
317 		       cache->ops->name);  in fscache_io_error()
322  * request withdrawal of all the objects in a cache
325 static void fscache_withdraw_all_objects(struct fscache_cache *cache,  in fscache_withdraw_all_objects()  argument
330 	while (!list_empty(&cache->object_list)) {  in fscache_withdraw_all_objects()
331 		spin_lock(&cache->object_list_lock);  in fscache_withdraw_all_objects()
333 		if (!list_empty(&cache->object_list)) {  in fscache_withdraw_all_objects()
334 			object = list_entry(cache->object_list.next,  in fscache_withdraw_all_objects()
346 		spin_unlock(&cache->object_list_lock);  in fscache_withdraw_all_objects()
352  * fscache_withdraw_cache - Withdraw a cache from the active service
353  * @cache: The record describing the cache
355  * Withdraw a cache from service, unbinding all its cache objects from the
361 void fscache_withdraw_cache(struct fscache_cache *cache)  in fscache_withdraw_cache()  argument
367 	pr_notice("Withdrawing cache \"%s\"\n",  in fscache_withdraw_cache()
368 		  cache->tag->name);  in fscache_withdraw_cache()
370 	/* make the cache unavailable for cookie acquisition */  in fscache_withdraw_cache()
371 	if (test_and_set_bit(FSCACHE_CACHE_WITHDRAWN, &cache->flags))  in fscache_withdraw_cache()
375 	list_del_init(&cache->link);  in fscache_withdraw_cache()
376 	cache->tag->cache = NULL;  in fscache_withdraw_cache()
382 	cache->ops->sync_cache(cache);  in fscache_withdraw_cache()
385 	/* dissociate all the netfs pages backed by this cache from the block  in fscache_withdraw_cache()
386 	 * mappings in the cache */  in fscache_withdraw_cache()
388 	cache->ops->dissociate_pages(cache);  in fscache_withdraw_cache()
392 	 * cache - which we do by passing them off to thread pool to be  in fscache_withdraw_cache()
396 	fscache_withdraw_all_objects(cache, &dying_objects);  in fscache_withdraw_cache()
402 		   atomic_read(&cache->object_count) == 0);  in fscache_withdraw_cache()
405 		   list_empty(&cache->object_list));  in fscache_withdraw_cache()
409 	kobject_put(cache->kobj);  in fscache_withdraw_cache()
411 	clear_bit(FSCACHE_TAG_RESERVED, &cache->tag->flags);  in fscache_withdraw_cache()
412 	fscache_release_cache_tag(cache->tag);  in fscache_withdraw_cache()
413 	cache->tag = NULL;  in fscache_withdraw_cache()