2 /* Volume-level cache cookie handling.
20 struct fscache_volume *fscache_get_volume(struct fscache_volume *volume,  in fscache_get_volume()  argument
25 	__refcount_inc(&volume->ref, &ref);  in fscache_get_volume()
26 	trace_fscache_volume(volume->debug_id, ref + 1, where);  in fscache_get_volume()
27 	return volume;  in fscache_get_volume()
30 static void fscache_see_volume(struct fscache_volume *volume,  in fscache_see_volume()  argument
33 	int ref = refcount_read(&volume->ref);  in fscache_see_volume()
35 	trace_fscache_volume(volume->debug_id, ref, where);  in fscache_see_volume()
39  * Pin the cache behind a volume so that we can access it.
41 static void __fscache_begin_volume_access(struct fscache_volume *volume,  in __fscache_begin_volume_access()  argument
47 	n_accesses = atomic_inc_return(&volume->n_accesses);  in __fscache_begin_volume_access()
49 	trace_fscache_access_volume(volume->debug_id, cookie ? cookie->debug_id : 0,  in __fscache_begin_volume_access()
50 				    refcount_read(&volume->ref),  in __fscache_begin_volume_access()
55  * fscache_begin_volume_access - Pin a cache so a volume can be accessed
56  * @volume: The volume cookie
61  * accessing a volume and returns true if successful.  This works as follows:
66  *  (2) If the cache tests as live, then we increment the volume's n_accesses
70  *  (3) When we end the access, we decrement the volume's n_accesses and wake
73  *  (4) Whilst the cache is caching, the volume's n_accesses is kept
77  *      accesses, the volume's n_accesses is decremented and we wait for it to
83 bool fscache_begin_volume_access(struct fscache_volume *volume,  in fscache_begin_volume_access()  argument
87 	if (!fscache_cache_is_live(volume->cache))  in fscache_begin_volume_access()
89 	__fscache_begin_volume_access(volume, cookie, why);  in fscache_begin_volume_access()
90 	if (!fscache_cache_is_live(volume->cache)) {  in fscache_begin_volume_access()
91 		fscache_end_volume_access(volume, cookie, fscache_access_unlive);  in fscache_begin_volume_access()
99  * @volume: The volume cookie
103  * Unpin a cache volume after we've accessed it.  The datafile @cookie and the
106 void fscache_end_volume_access(struct fscache_volume *volume,  in fscache_end_volume_access()  argument
113 	n_accesses = atomic_dec_return(&volume->n_accesses);  in fscache_end_volume_access()
114 	trace_fscache_access_volume(volume->debug_id, cookie ? cookie->debug_id : 0,  in fscache_end_volume_access()
115 				    refcount_read(&volume->ref),  in fscache_end_volume_access()
118 		wake_up_var(&volume->n_accesses);  in fscache_end_volume_access()
136 static bool fscache_is_acquire_pending(struct fscache_volume *volume)  in fscache_is_acquire_pending()  argument
138 	return test_bit(FSCACHE_VOLUME_ACQUIRE_PENDING, &volume->flags);  in fscache_is_acquire_pending()
147 		pr_notice("Potential volume collision new=%08x old=%08x",  in fscache_wait_on_volume_collision()
156  * Attempt to insert the new volume into the hash.  If there's a collision, we
157  * wait for the old volume to complete if it's being relinquished and an error
197  * Allocate and initialise a volume representation cookie.
204 	struct fscache_volume *volume;  in fscache_alloc_volume()  local
220 	volume = kzalloc(struct_size(volume, coherency, coherency_len),  in fscache_alloc_volume()
222 	if (!volume)  in fscache_alloc_volume()
225 	volume->cache = cache;  in fscache_alloc_volume()
226 	volume->coherency_len = coherency_len;  in fscache_alloc_volume()
228 		memcpy(volume->coherency, coherency_data, coherency_len);  in fscache_alloc_volume()
229 	INIT_LIST_HEAD(&volume->proc_link);  in fscache_alloc_volume()
230 	INIT_WORK(&volume->work, fscache_create_volume_work);  in fscache_alloc_volume()
231 	refcount_set(&volume->ref, 1);  in fscache_alloc_volume()
232 	spin_lock_init(&volume->lock);  in fscache_alloc_volume()
244 	volume->key = key;  in fscache_alloc_volume()
245 	volume->key_hash = fscache_hash(0, key, hlen);  in fscache_alloc_volume()
247 	volume->debug_id = atomic_inc_return(&fscache_volume_debug_id);  in fscache_alloc_volume()
250 	list_add_tail(&volume->proc_link, &fscache_volumes);  in fscache_alloc_volume()
251 	fscache_see_volume(volume, fscache_volume_new_acquire);  in fscache_alloc_volume()
254 	_leave(" = v=%x", volume->debug_id);  in fscache_alloc_volume()
255 	return volume;  in fscache_alloc_volume()
258 	kfree(volume);  in fscache_alloc_volume()
266  * Create a volume's representation on disk.  Have a volume ref and a cache
272 	struct fscache_volume *volume =  in fscache_create_volume_work()  local
275 	fscache_see_volume(volume, fscache_volume_see_create_work);  in fscache_create_volume_work()
277 	ops = volume->cache->ops;  in fscache_create_volume_work()
279 		ops->acquire_volume(volume);  in fscache_create_volume_work()
280 	fscache_end_cache_access(volume->cache,  in fscache_create_volume_work()
283 	clear_and_wake_up_bit(FSCACHE_VOLUME_CREATING, &volume->flags);  in fscache_create_volume_work()
284 	fscache_put_volume(volume, fscache_volume_put_create_work);  in fscache_create_volume_work()
288  * Dispatch a worker thread to create a volume's representation on disk.
290 void fscache_create_volume(struct fscache_volume *volume, bool wait)  in fscache_create_volume()  argument
292 	if (test_and_set_bit(FSCACHE_VOLUME_CREATING, &volume->flags))  in fscache_create_volume()
294 	if (volume->cache_priv)  in fscache_create_volume()
296 	if (!fscache_begin_cache_access(volume->cache,  in fscache_create_volume()
300 	fscache_get_volume(volume, fscache_volume_get_create_work);  in fscache_create_volume()
301 	if (!schedule_work(&volume->work))  in fscache_create_volume()
302 		fscache_put_volume(volume, fscache_volume_put_create_work);  in fscache_create_volume()
306 		fscache_see_volume(volume, fscache_volume_wait_create_work);  in fscache_create_volume()
307 		wait_on_bit(&volume->flags, FSCACHE_VOLUME_CREATING,  in fscache_create_volume()
312 	clear_bit_unlock(FSCACHE_VOLUME_CREATING, &volume->flags);  in fscache_create_volume()
313 	wake_up_bit(&volume->flags, FSCACHE_VOLUME_CREATING);  in fscache_create_volume()
317  * Acquire a volume representation cookie and link it to a (proposed) cache.
324 	struct fscache_volume *volume;  in __fscache_acquire_volume()  local
326 	volume = fscache_alloc_volume(volume_key, cache_name,  in __fscache_acquire_volume()
328 	if (!volume)  in __fscache_acquire_volume()
331 	if (!fscache_hash_volume(volume)) {  in __fscache_acquire_volume()
332 		fscache_put_volume(volume, fscache_volume_put_hash_collision);  in __fscache_acquire_volume()
336 	fscache_create_volume(volume, false);  in __fscache_acquire_volume()
337 	return volume;  in __fscache_acquire_volume()
341 static void fscache_wake_pending_volume(struct fscache_volume *volume,  in fscache_wake_pending_volume()  argument
348 		if (fscache_volume_same(cursor, volume)) {  in fscache_wake_pending_volume()
358  * Remove a volume cookie from the hash table.
360 static void fscache_unhash_volume(struct fscache_volume *volume)  in fscache_unhash_volume()  argument
365 	bucket = volume->key_hash & (ARRAY_SIZE(fscache_volume_hash) - 1);  in fscache_unhash_volume()
369 	hlist_bl_del(&volume->hash_link);  in fscache_unhash_volume()
370 	if (test_bit(FSCACHE_VOLUME_COLLIDED_WITH, &volume->flags))  in fscache_unhash_volume()
371 		fscache_wake_pending_volume(volume, h);  in fscache_unhash_volume()
376  * Drop a cache's volume attachments.
378 static void fscache_free_volume(struct fscache_volume *volume)  in fscache_free_volume()  argument
380 	struct fscache_cache *cache = volume->cache;  in fscache_free_volume()
382 	if (volume->cache_priv) {  in fscache_free_volume()
383 		__fscache_begin_volume_access(volume, NULL,  in fscache_free_volume()
385 		if (volume->cache_priv)  in fscache_free_volume()
386 			cache->ops->free_volume(volume);  in fscache_free_volume()
387 		fscache_end_volume_access(volume, NULL,  in fscache_free_volume()
392 	list_del_init(&volume->proc_link);  in fscache_free_volume()
393 	atomic_dec(&volume->cache->n_volumes);  in fscache_free_volume()
396 	if (!hlist_bl_unhashed(&volume->hash_link))  in fscache_free_volume()
397 		fscache_unhash_volume(volume);  in fscache_free_volume()
399 	trace_fscache_volume(volume->debug_id, 0, fscache_volume_free);  in fscache_free_volume()
400 	kfree(volume->key);  in fscache_free_volume()
401 	kfree(volume);  in fscache_free_volume()
407  * Drop a reference to a volume cookie.
409 void fscache_put_volume(struct fscache_volume *volume,  in fscache_put_volume()  argument
412 	if (volume) {  in fscache_put_volume()
413 		unsigned int debug_id = volume->debug_id;  in fscache_put_volume()
417 		zero = __refcount_dec_and_test(&volume->ref, &ref);  in fscache_put_volume()
420 			fscache_free_volume(volume);  in fscache_put_volume()
425  * Relinquish a volume representation cookie.
427 void __fscache_relinquish_volume(struct fscache_volume *volume,  in __fscache_relinquish_volume()  argument
431 	if (WARN_ON(test_and_set_bit(FSCACHE_VOLUME_RELINQUISHED, &volume->flags)))  in __fscache_relinquish_volume()
435 		set_bit(FSCACHE_VOLUME_INVALIDATE, &volume->flags);  in __fscache_relinquish_volume()
437 		memcpy(volume->coherency, coherency_data, volume->coherency_len);  in __fscache_relinquish_volume()
440 	fscache_put_volume(volume, fscache_volume_put_relinquish);  in __fscache_relinquish_volume()
445  * fscache_withdraw_volume - Withdraw a volume from being cached
446  * @volume: Volume cookie
448  * Withdraw a cache volume from service, waiting for all accesses to complete
451 void fscache_withdraw_volume(struct fscache_volume *volume)  in fscache_withdraw_volume()  argument
455 	_debug("withdraw V=%x", volume->debug_id);  in fscache_withdraw_volume()
458 	n_accesses = atomic_dec_return(&volume->n_accesses);  in fscache_withdraw_volume()
459 	trace_fscache_access_volume(volume->debug_id, 0,  in fscache_withdraw_volume()
460 				    refcount_read(&volume->ref),  in fscache_withdraw_volume()
463 	wait_var_event(&volume->n_accesses,  in fscache_withdraw_volume()
464 		       atomic_read(&volume->n_accesses) == 0);  in fscache_withdraw_volume()
474 	struct fscache_volume *volume;  in fscache_volumes_seq_show()  local
478 			 "VOLUME   REF   nCOOK ACC FL CACHE           KEY\n"  in fscache_volumes_seq_show()
483 	volume = list_entry(v, struct fscache_volume, proc_link);  in fscache_volumes_seq_show()
486 		   volume->debug_id,  in fscache_volumes_seq_show()
487 		   refcount_read(&volume->ref),  in fscache_volumes_seq_show()
488 		   atomic_read(&volume->n_cookies),  in fscache_volumes_seq_show()
489 		   atomic_read(&volume->n_accesses),  in fscache_volumes_seq_show()
490 		   volume->flags,  in fscache_volumes_seq_show()
491 		   volume->cache->name ?: "-",  in fscache_volumes_seq_show()
492 		   volume->key + 1);  in fscache_volumes_seq_show()