1 /* Blue Sky: File Systems in the Cloud
3 * Copyright (C) 2009 The Regents of the University of California
4 * Written by Michael Vrable <mvrable@cs.ucsd.edu>
13 #include "bluesky-private.h"
15 /* Interaction with cloud storage. We expose very simple GET/PUT style
16 * interface, which different backends can implement. Available backends
17 * (will) include Amazon S3 and a simple local store for testing purposes.
18 * Operations may be performed asynchronously. */
20 struct _BlueSkyStore {
21 const BlueSkyStoreImplementation *impl;
26 int pending; /* Count of operations not yet complete. */
29 GHashTable *store_implementations;
31 /* Thread pool for calling notifier functions when an operation completes.
32 * These are called in a separate thread for locking reasons: we want to call
33 * the notifiers without the lock on the async object held, but completion
34 * occurs when the lock is held--so we need some way to defer the call. This
35 * isn't really optimal from a cache-locality standpoint. */
36 static GThreadPool *notifier_thread_pool;
38 void bluesky_store_register(const BlueSkyStoreImplementation *impl,
41 g_hash_table_insert(store_implementations, g_strdup(name), (gpointer)impl);
44 BlueSkyStore *bluesky_store_new(const gchar *type)
46 const BlueSkyStoreImplementation *impl;
49 scheme = g_strdup(type);
50 path = strchr(scheme, ':');
56 impl = g_hash_table_lookup(store_implementations, scheme);
62 gpointer handle = impl->create(path);
68 BlueSkyStore *store = g_new(BlueSkyStore, 1);
70 store->handle = handle;
71 store->lock = g_mutex_new();
72 store->cond_idle = g_cond_new();
78 void bluesky_store_free(BlueSkyStore *store)
80 store->impl->destroy(store->handle);
84 BlueSkyStoreAsync *bluesky_store_async_new(BlueSkyStore *store)
86 BlueSkyStoreAsync *async;
88 async = g_new(BlueSkyStoreAsync, 1);
90 async->lock = g_mutex_new();
91 async->completion_cond = g_cond_new();
93 async->status = ASYNC_NEW;
94 async->op = STORE_OP_NONE;
98 async->notifiers = NULL;
99 async->notifier_count = 0;
100 async->store_private = NULL;
105 gpointer bluesky_store_async_get_handle(BlueSkyStoreAsync *async)
107 return async->store->handle;
110 void bluesky_store_async_ref(BlueSkyStoreAsync *async)
115 g_return_if_fail(g_atomic_int_get(&async->refcount) > 0);
117 g_atomic_int_inc(&async->refcount);
120 void bluesky_store_async_unref(BlueSkyStoreAsync *async)
125 if (g_atomic_int_dec_and_test(&async->refcount)) {
126 async->store->impl->cleanup(async->store->handle, async);
127 g_mutex_free(async->lock);
128 g_cond_free(async->completion_cond);
130 bluesky_string_unref(async->data);
135 /* Block until the given operation has completed. */
136 void bluesky_store_async_wait(BlueSkyStoreAsync *async)
138 g_return_if_fail(async != NULL);
139 g_mutex_lock(async->lock);
141 if (async->status == ASYNC_NEW) {
142 g_error("bluesky_store_async_wait on a new async object!\n");
143 g_mutex_unlock(async->lock);
147 while (async->status != ASYNC_COMPLETE
148 || g_atomic_int_get(&async->notifier_count) > 0) {
149 g_cond_wait(async->completion_cond, async->lock);
152 g_mutex_unlock(async->lock);
155 /* Add a notifier function to be called when the operation completes. */
156 void bluesky_store_async_add_notifier(BlueSkyStoreAsync *async,
157 GFunc func, gpointer user_data)
159 struct BlueSkyNotifierList *nl = g_new(struct BlueSkyNotifierList, 1);
160 g_mutex_lock(async->lock);
161 nl->next = async->notifiers;
163 nl->async = async; bluesky_store_async_ref(async);
164 nl->user_data = user_data;
165 g_atomic_int_inc(&async->notifier_count);
166 if (async->status == ASYNC_COMPLETE) {
167 g_thread_pool_push(notifier_thread_pool, nl, NULL);
169 async->notifiers = nl;
171 g_mutex_unlock(async->lock);
174 /* Mark an asynchronous operation as complete. This should only be called by
175 * the store implementations. The lock should be held when calling this
176 * function. Any notifier functions will be called, but in a separate thread
177 * and without the lock held. */
178 void bluesky_store_async_mark_complete(BlueSkyStoreAsync *async)
180 g_return_if_fail(async->status != ASYNC_COMPLETE);
182 bluesky_time_hires elapsed = bluesky_now_hires() - async->start_time;
184 g_mutex_lock(async->store->lock);
185 async->store->pending--;
186 if (async->store->pending == 0)
187 g_cond_broadcast(async->store->cond_idle);
188 g_mutex_unlock(async->store->lock);
190 async->status = ASYNC_COMPLETE;
191 g_cond_broadcast(async->completion_cond);
193 while (async->notifiers != NULL) {
194 struct BlueSkyNotifierList *nl = async->notifiers;
195 async->notifiers = nl->next;
196 g_thread_pool_push(notifier_thread_pool, nl, NULL);
199 g_log("bluesky/store", G_LOG_LEVEL_DEBUG,
200 "[%p] complete: elapsed = %"PRIi64" ns",
204 void bluesky_store_async_submit(BlueSkyStoreAsync *async)
206 BlueSkyStore *store = async->store;
208 async->start_time = bluesky_now_hires();
210 g_log("bluesky/store", G_LOG_LEVEL_DEBUG, "[%p] submit: %s %s",
212 async->op == STORE_OP_GET ? "GET"
213 : async->op == STORE_OP_PUT ? "PUT"
214 : async->op == STORE_OP_DELETE ? "DELETE"
215 : async->op == STORE_OP_BARRIER ? "BARRIER" : "???",
218 /* Barriers are handled specially, and not handed down the storage
219 * implementation layer. */
220 if (async->op == STORE_OP_BARRIER) {
221 async->status = ASYNC_RUNNING;
222 if (GPOINTER_TO_INT(async->store_private) == 0)
223 bluesky_store_async_mark_complete(async);
227 g_mutex_lock(async->store->lock);
228 async->store->pending++;
229 g_mutex_unlock(async->store->lock);
231 store->impl->submit(store->handle, async);
233 if (bluesky_options.synchronous_stores)
234 bluesky_store_async_wait(async);
237 static void op_complete(gpointer a, gpointer b)
239 BlueSkyStoreAsync *barrier = (BlueSkyStoreAsync *)b;
241 bluesky_store_async_ref(barrier);
242 g_mutex_lock(barrier->lock);
243 barrier->store_private
244 = GINT_TO_POINTER(GPOINTER_TO_INT(barrier->store_private) - 1);
245 if (GPOINTER_TO_INT(barrier->store_private) == 0
246 && barrier->status != ASYNC_NEW) {
247 bluesky_store_async_mark_complete(barrier);
249 g_mutex_unlock(barrier->lock);
250 bluesky_store_async_unref(barrier);
253 /* Add the given operation to the barrier. The barrier will not complete until
254 * all operations added to it have completed. */
255 void bluesky_store_add_barrier(BlueSkyStoreAsync *barrier,
256 BlueSkyStoreAsync *async)
258 g_return_if_fail(barrier->op == STORE_OP_BARRIER);
259 barrier->store_private
260 = GINT_TO_POINTER(GPOINTER_TO_INT(barrier->store_private) + 1);
261 bluesky_store_async_add_notifier(async, op_complete, barrier);
264 static void notifier_task(gpointer n, gpointer s)
266 struct BlueSkyNotifierList *notifier = (struct BlueSkyNotifierList *)n;
268 notifier->func(notifier->async, notifier->user_data);
269 if (g_atomic_int_dec_and_test(¬ifier->async->notifier_count)) {
270 g_cond_broadcast(notifier->async->completion_cond);
272 bluesky_store_async_unref(notifier->async);
276 void bluesky_store_sync(BlueSkyStore *store)
278 g_mutex_lock(store->lock);
279 g_print("Waiting for pending store operations to complete...\n");
280 while (store->pending > 0) {
281 g_cond_wait(store->cond_idle, store->lock);
283 g_mutex_unlock(store->lock);
284 g_print("Operations are complete.\n");
287 /* Convenience wrappers that perform a single operation synchronously. */
288 BlueSkyRCStr *bluesky_store_get(BlueSkyStore *store, const gchar *key)
290 BlueSkyStoreAsync *async = bluesky_store_async_new(store);
291 async->op = STORE_OP_GET;
292 async->key = g_strdup(key);
293 bluesky_store_async_submit(async);
295 bluesky_store_async_wait(async);
297 BlueSkyRCStr *data = async->data;
298 bluesky_string_ref(data);
299 bluesky_store_async_unref(async);
303 void bluesky_store_put(BlueSkyStore *store,
304 const gchar *key, BlueSkyRCStr *val)
306 BlueSkyStoreAsync *async = bluesky_store_async_new(store);
307 async->op = STORE_OP_PUT;
308 async->key = g_strdup(key);
309 bluesky_string_ref(val);
311 bluesky_store_async_submit(async);
313 bluesky_store_async_wait(async);
314 bluesky_store_async_unref(async);
317 /* Simple in-memory data store for test purposes. */
321 /* TODO: A hashtable isn't optimal for list queries... */
325 static gpointer memstore_create(const gchar *path)
327 MemStore *store = g_new(MemStore, 1);
328 store->lock = g_mutex_new();
329 store->store = g_hash_table_new_full(g_str_hash, g_str_equal,
331 (GDestroyNotify)bluesky_string_unref);
333 return (gpointer)store;
336 static void memstore_destroy(gpointer store)
341 static BlueSkyRCStr *memstore_get(gpointer st, const gchar *key)
343 MemStore *store = (MemStore *)st;
344 BlueSkyRCStr *s = g_hash_table_lookup(store->store, key);
346 bluesky_string_ref(s);
350 static void memstore_put(gpointer s, const gchar *key, BlueSkyRCStr *val)
352 MemStore *store = (MemStore *)s;
353 bluesky_string_ref(val);
354 g_hash_table_insert(store->store, g_strdup(key), val);
357 static void memstore_submit(gpointer s, BlueSkyStoreAsync *async)
359 g_return_if_fail(async->status == ASYNC_NEW);
360 g_return_if_fail(async->op != STORE_OP_NONE);
364 async->data = memstore_get(s, async->key);
368 memstore_put(s, async->key, async->data);
372 g_warning("Uknown operation type for MemStore: %d\n", async->op);
376 bluesky_store_async_mark_complete(async);
379 static void memstore_cleanup(gpointer store, BlueSkyStoreAsync *async)
383 static BlueSkyStoreImplementation memstore_impl = {
384 .create = memstore_create,
385 .destroy = memstore_destroy,
386 .submit = memstore_submit,
387 .cleanup = memstore_cleanup,
390 /* Store implementation which writes data as files to disk. */
391 static gpointer filestore_create(const gchar *path)
393 return GINT_TO_POINTER(1);
396 static void filestore_destroy()
400 static BlueSkyRCStr *filestore_get(const gchar *key)
402 gchar *contents = NULL;
404 GError *error = NULL;
406 g_file_get_contents(key, &contents, &length, &error);
407 if (contents == NULL)
410 return bluesky_string_new(contents, length);
413 static void filestore_put(const gchar *key, BlueSkyRCStr *val)
415 g_file_set_contents(key, val->data, val->len, NULL);
418 static void filestore_submit(gpointer s, BlueSkyStoreAsync *async)
420 g_return_if_fail(async->status == ASYNC_NEW);
421 g_return_if_fail(async->op != STORE_OP_NONE);
425 async->data = filestore_get(async->key);
430 filestore_put(async->key, async->data);
435 g_warning("Uknown operation type for FileStore: %d\n", async->op);
439 bluesky_store_async_mark_complete(async);
442 static void filestore_cleanup(gpointer store, BlueSkyStoreAsync *async)
446 static BlueSkyStoreImplementation filestore_impl = {
447 .create = filestore_create,
448 .destroy = filestore_destroy,
449 .submit = filestore_submit,
450 .cleanup = filestore_cleanup,
453 void bluesky_store_init()
455 store_implementations = g_hash_table_new(g_str_hash, g_str_equal);
456 notifier_thread_pool = g_thread_pool_new(notifier_task, NULL, -1, FALSE,
458 bluesky_store_register(&memstore_impl, "mem");
459 bluesky_store_register(&filestore_impl, "file");