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;
48 impl = g_hash_table_lookup(store_implementations, type);
52 gpointer handle = impl->create();
56 BlueSkyStore *store = g_new(BlueSkyStore, 1);
58 store->handle = handle;
59 store->lock = g_mutex_new();
60 store->cond_idle = g_cond_new();
65 void bluesky_store_free(BlueSkyStore *store)
67 store->impl->destroy(store->handle);
71 BlueSkyStoreAsync *bluesky_store_async_new(BlueSkyStore *store)
73 BlueSkyStoreAsync *async;
75 async = g_new(BlueSkyStoreAsync, 1);
77 async->lock = g_mutex_new();
78 async->completion_cond = g_cond_new();
80 async->status = ASYNC_NEW;
81 async->op = STORE_OP_NONE;
85 async->notifiers = NULL;
86 async->store_private = NULL;
91 void bluesky_store_async_ref(BlueSkyStoreAsync *async)
96 g_return_if_fail(g_atomic_int_get(&async->refcount) > 0);
98 g_atomic_int_inc(&async->refcount);
101 void bluesky_store_async_unref(BlueSkyStoreAsync *async)
106 if (g_atomic_int_dec_and_test(&async->refcount)) {
107 async->store->impl->cleanup(async->store->handle, async);
108 g_mutex_free(async->lock);
109 g_cond_free(async->completion_cond);
111 bluesky_string_unref(async->data);
116 /* Block until the given operation has completed. */
117 void bluesky_store_async_wait(BlueSkyStoreAsync *async)
119 g_return_if_fail(async != NULL);
120 g_mutex_lock(async->lock);
122 if (async->status == ASYNC_NEW) {
123 g_error("bluesky_store_async_wait on a new async object!\n");
124 g_mutex_unlock(async->lock);
128 while (async->status != ASYNC_COMPLETE) {
129 g_cond_wait(async->completion_cond, async->lock);
132 g_mutex_unlock(async->lock);
135 /* Add a notifier function to be called when the operation completes. */
136 void bluesky_store_async_add_notifier(BlueSkyStoreAsync *async,
137 GFunc func, gpointer user_data)
139 struct BlueSkyNotifierList *nl = g_new(struct BlueSkyNotifierList, 1);
140 nl->next = async->notifiers;
142 nl->async = async; bluesky_store_async_ref(async);
143 nl->user_data = user_data;
144 if (async->status == ASYNC_COMPLETE) {
145 g_thread_pool_push(notifier_thread_pool, nl, NULL);
147 async->notifiers = nl;
151 /* Mark an asynchronous operation as complete. This should only be called by
152 * the store implementations. The lock should be held when calling this
153 * function. Any notifier functions will be called, but in a separate thread
154 * and without the lock held. */
155 void bluesky_store_async_mark_complete(BlueSkyStoreAsync *async)
157 g_return_if_fail(async->status != ASYNC_COMPLETE);
159 bluesky_time_hires elapsed = bluesky_now_hires() - async->start_time;
161 g_mutex_lock(async->store->lock);
162 async->store->pending--;
163 if (async->store->pending == 0)
164 g_cond_broadcast(async->store->cond_idle);
165 g_mutex_unlock(async->store->lock);
167 async->status = ASYNC_COMPLETE;
168 g_cond_broadcast(async->completion_cond);
170 while (async->notifiers != NULL) {
171 struct BlueSkyNotifierList *nl = async->notifiers;
172 async->notifiers = nl->next;
173 g_thread_pool_push(notifier_thread_pool, nl, NULL);
176 g_log("bluesky/store", G_LOG_LEVEL_DEBUG,
177 "[%p] complete: elapsed = %"PRIi64" ns",
181 void bluesky_store_async_submit(BlueSkyStoreAsync *async)
183 BlueSkyStore *store = async->store;
185 async->start_time = bluesky_now_hires();
187 g_log("bluesky/store", G_LOG_LEVEL_DEBUG, "[%p] submit: %s %s",
189 async->op == STORE_OP_GET ? "GET"
190 : async->op == STORE_OP_PUT ? "PUT"
191 : async->op == STORE_OP_DELETE ? "DELETE"
192 : async->op == STORE_OP_BARRIER ? "BARRIER" : "???",
195 /* Barriers are handled specially, and not handed down the storage
196 * implementation layer. */
197 if (async->op == STORE_OP_BARRIER) {
198 async->status = ASYNC_RUNNING;
199 if (GPOINTER_TO_INT(async->store_private) == 0)
200 bluesky_store_async_mark_complete(async);
204 g_mutex_lock(async->store->lock);
205 async->store->pending++;
206 g_mutex_unlock(async->store->lock);
208 store->impl->submit(store->handle, async);
210 if (bluesky_options.synchronous_stores)
211 bluesky_store_async_wait(async);
214 static void op_complete(gpointer a, gpointer b)
216 BlueSkyStoreAsync *barrier = (BlueSkyStoreAsync *)b;
218 g_mutex_lock(barrier->lock);
219 barrier->store_private
220 = GINT_TO_POINTER(GPOINTER_TO_INT(barrier->store_private) - 1);
221 if (GPOINTER_TO_INT(barrier->store_private) == 0
222 && barrier->status != ASYNC_NEW) {
223 bluesky_store_async_mark_complete(barrier);
225 g_mutex_unlock(barrier->lock);
228 /* Add the given operation to the barrier. The barrier will not complete until
229 * all operations added to it have completed. */
230 void bluesky_store_add_barrier(BlueSkyStoreAsync *barrier,
231 BlueSkyStoreAsync *async)
233 g_return_if_fail(barrier->op == STORE_OP_BARRIER);
234 barrier->store_private
235 = GINT_TO_POINTER(GPOINTER_TO_INT(barrier->store_private) + 1);
236 bluesky_store_async_add_notifier(async, op_complete, barrier);
239 static void notifier_task(gpointer n, gpointer s)
241 struct BlueSkyNotifierList *notifier = (struct BlueSkyNotifierList *)n;
243 notifier->func(notifier->async, notifier->user_data);
244 bluesky_store_async_unref(notifier->async);
248 void bluesky_store_sync(BlueSkyStore *store)
250 g_mutex_lock(store->lock);
251 g_print("Waiting for pending store operations to complete...\n");
252 while (store->pending > 0) {
253 g_cond_wait(store->cond_idle, store->lock);
255 g_mutex_unlock(store->lock);
256 g_print("Operations are complete.\n");
259 /* Convenience wrappers that perform a single operation synchronously. */
260 BlueSkyRCStr *bluesky_store_get(BlueSkyStore *store, const gchar *key)
262 BlueSkyStoreAsync *async = bluesky_store_async_new(store);
263 async->op = STORE_OP_GET;
264 async->key = g_strdup(key);
265 bluesky_store_async_submit(async);
267 bluesky_store_async_wait(async);
269 BlueSkyRCStr *data = async->data;
270 bluesky_string_ref(data);
271 bluesky_store_async_unref(async);
275 void bluesky_store_put(BlueSkyStore *store,
276 const gchar *key, BlueSkyRCStr *val)
278 BlueSkyStoreAsync *async = bluesky_store_async_new(store);
279 async->op = STORE_OP_PUT;
280 async->key = g_strdup(key);
281 bluesky_string_ref(val);
283 bluesky_store_async_submit(async);
285 bluesky_store_async_wait(async);
286 bluesky_store_async_unref(async);
289 /* Simple in-memory data store for test purposes. */
293 /* TODO: A hashtable isn't optimal for list queries... */
297 static gpointer memstore_create()
299 MemStore *store = g_new(MemStore, 1);
300 store->lock = g_mutex_new();
301 store->store = g_hash_table_new_full(g_str_hash, g_str_equal,
303 (GDestroyNotify)bluesky_string_unref);
305 return (gpointer)store;
308 static void memstore_destroy(gpointer store)
313 static BlueSkyRCStr *memstore_get(gpointer st, const gchar *key)
315 MemStore *store = (MemStore *)st;
316 BlueSkyRCStr *s = g_hash_table_lookup(store->store, key);
318 bluesky_string_ref(s);
322 static void memstore_put(gpointer s, const gchar *key, BlueSkyRCStr *val)
324 MemStore *store = (MemStore *)s;
325 bluesky_string_ref(val);
326 g_hash_table_insert(store->store, g_strdup(key), val);
329 static void memstore_submit(gpointer s, BlueSkyStoreAsync *async)
331 g_return_if_fail(async->status == ASYNC_NEW);
332 g_return_if_fail(async->op != STORE_OP_NONE);
336 async->data = memstore_get(s, async->key);
340 memstore_put(s, async->key, async->data);
344 g_warning("Uknown operation type for MemStore: %d\n", async->op);
348 bluesky_store_async_mark_complete(async);
351 static void memstore_cleanup(gpointer store, BlueSkyStoreAsync *async)
355 static BlueSkyStoreImplementation memstore_impl = {
356 .create = memstore_create,
357 .destroy = memstore_destroy,
358 .submit = memstore_submit,
359 .cleanup = memstore_cleanup,
362 /* Store implementation which writes data as files to disk. */
363 static gpointer filestore_create()
365 return GINT_TO_POINTER(1);
368 static void filestore_destroy()
372 static BlueSkyRCStr *filestore_get(const gchar *key)
374 gchar *contents = NULL;
376 GError *error = NULL;
378 g_file_get_contents(key, &contents, &length, &error);
379 if (contents == NULL)
382 return bluesky_string_new(contents, length);
385 static void filestore_put(const gchar *key, BlueSkyRCStr *val)
387 g_file_set_contents(key, val->data, val->len, NULL);
390 static void filestore_submit(gpointer s, BlueSkyStoreAsync *async)
392 g_return_if_fail(async->status == ASYNC_NEW);
393 g_return_if_fail(async->op != STORE_OP_NONE);
397 async->data = filestore_get(async->key);
401 filestore_put(async->key, async->data);
405 g_warning("Uknown operation type for FileStore: %d\n", async->op);
409 bluesky_store_async_mark_complete(async);
412 static void filestore_cleanup(gpointer store, BlueSkyStoreAsync *async)
416 static BlueSkyStoreImplementation filestore_impl = {
417 .create = filestore_create,
418 .destroy = filestore_destroy,
419 .submit = filestore_submit,
420 .cleanup = filestore_cleanup,
423 void bluesky_store_init()
425 store_implementations = g_hash_table_new(g_str_hash, g_str_equal);
426 notifier_thread_pool = g_thread_pool_new(notifier_task, NULL, -1, FALSE,
428 bluesky_store_register(&memstore_impl, "mem");
429 bluesky_store_register(&filestore_impl, "file");