fs/cachefiles/cache.c

2 /* Manage high-level VFS aspects of a cache.
14  * Bring a cache online.
16 int cachefiles_add_cache(struct cachefiles_cache *cache)
27 	cache_cookie = fscache_acquire_cache(cache->tag);
32 	ret = cachefiles_get_security_ID(cache);
36 	cachefiles_begin_secure(cache, &saved_cred);
38 	/* look up the directory at the root of the cache */
39 	ret = kern_path(cache->rootdirname, LOOKUP_DIRECTORY, &path);
43 	cache->mnt = path.mnt;
48 		pr_warn("File cache on idmapped mounts not supported");
57 	 * - We want to be able to sync the filesystem when stopping the cache
75 	/* determine the security of the on-disk cache as this governs
77 	ret = cachefiles_determine_cache_security(cache, root, &saved_cred);
81 	/* get the cache size and blocksize */
94 	cache->bsize = stats.f_bsize;
95 	cache->bshift = ilog2(stats.f_bsize);
98 	       cache->bsize, cache->bshift);
106 	cache->fstop = stats.f_files * cache->fstop_percent;
107 	cache->fcull = stats.f_files * cache->fcull_percent;
108 	cache->frun  = stats.f_files * cache->frun_percent;
111 	       (unsigned long long) cache->frun,
112 	       (unsigned long long) cache->fcull,
113 	       (unsigned long long) cache->fstop);
116 	cache->bstop = stats.f_blocks * cache->bstop_percent;
117 	cache->bcull = stats.f_blocks * cache->bcull_percent;
118 	cache->brun  = stats.f_blocks * cache->brun_percent;
121 	       (unsigned long long) cache->brun,
122 	       (unsigned long long) cache->bcull,
123 	       (unsigned long long) cache->bstop);
125 	/* get the cache directory and check its type */
126 	cachedir = cachefiles_get_directory(cache, root, "cache", NULL);
132 	cache->store = cachedir;
135 	graveyard = cachefiles_get_directory(cache, root, "graveyard", NULL);
141 	cache->graveyard = graveyard;
142 	cache->cache = cache_cookie;
144 	ret = fscache_add_cache(cache_cookie, &cachefiles_cache_ops, cache);
149 	set_bit(CACHEFILES_READY, &cache->flags);
152 	pr_info("File cache on %s registered\n", cache_cookie->name);
154 	/* check how much space the cache has */
155 	cachefiles_has_space(cache, 0, 0, cachefiles_has_space_check);
156 	cachefiles_end_secure(cache, saved_cred);
157 	_leave(" = 0 [%px]", cache->cache);
161 	cachefiles_put_directory(cache->graveyard);
162 	cache->graveyard = NULL;
164 	cachefiles_put_directory(cache->store);
165 	cache->store = NULL;
166 	mntput(cache->mnt);
167 	cache->mnt = NULL;
170 	cachefiles_end_secure(cache, saved_cred);
171 	put_cred(cache->cache_cred);
172 	cache->cache_cred = NULL;
175 	cache->cache = NULL;
182  * cache
184 int cachefiles_has_space(struct cachefiles_cache *cache,
193 		.mnt	= cache->mnt,
194 		.dentry	= cache->mnt->mnt_root,
198 	//       (unsigned long long) cache->frun,
199 	//       (unsigned long long) cache->fcull,
200 	//       (unsigned long long) cache->fstop,
201 	//       (unsigned long long) cache->brun,
202 	//       (unsigned long long) cache->bcull,
203 	//       (unsigned long long) cache->bstop,
214 			cachefiles_io_error(cache, "statfs failed");
220 	b_writing = atomic_long_read(&cache->b_writing);
242 	if (stats.f_ffree < cache->fstop ||
243 	    b_avail < cache->bstop)
247 	if (stats.f_ffree < cache->fcull ||
248 	    b_avail < cache->bcull)
251 	if (test_bit(CACHEFILES_CULLING, &cache->flags) &&
252 	    stats.f_ffree >= cache->frun &&
253 	    b_avail >= cache->brun &&
254 	    test_and_clear_bit(CACHEFILES_CULLING, &cache->flags)
257 		cachefiles_state_changed(cache);
275 	if (!test_and_set_bit(CACHEFILES_CULLING, &cache->flags)) {
277 		cachefiles_state_changed(cache);
287 static void cachefiles_withdraw_objects(struct cachefiles_cache *cache)
294 	spin_lock(&cache->object_list_lock);
296 	while (!list_empty(&cache->object_list)) {
297 		object = list_first_entry(&cache->object_list,
304 			spin_unlock(&cache->object_list_lock);
306 			spin_lock(&cache->object_list_lock);
310 	spin_unlock(&cache->object_list_lock);
317 static void cachefiles_withdraw_volumes(struct cachefiles_cache *cache)
324 		spin_lock(&cache->object_list_lock);
325 		if (!list_empty(&cache->volumes)) {
326 			volume = list_first_entry(&cache->volumes,
330 		spin_unlock(&cache->object_list_lock);
341  * Sync a cache to backing disk.
343 static void cachefiles_sync_cache(struct cachefiles_cache *cache)
348 	_enter("%s", cache->cache->name);
352 	cachefiles_begin_secure(cache, &saved_cred);
353 	down_read(&cache->mnt->mnt_sb->s_umount);
354 	ret = sync_filesystem(cache->mnt->mnt_sb);
355 	up_read(&cache->mnt->mnt_sb->s_umount);
356 	cachefiles_end_secure(cache, saved_cred);
359 		cachefiles_io_error(cache,
365  * Withdraw cache objects.
367 void cachefiles_withdraw_cache(struct cachefiles_cache *cache)
369 	struct fscache_cache *fscache = cache->cache;
371 	pr_info("File cache on %s unregistering\n", fscache->name);
376 	 * cache - which we do by passing them off to thread pool to be
378 	cachefiles_withdraw_objects(cache);
381 	cachefiles_withdraw_volumes(cache);
382 	cachefiles_sync_cache(cache);
383 	cache->cache = NULL;