A few attempted bugfixes for log data lifetimes.

[bluesky.git] / bluesky / cloudlog.c

diff --git a/bluesky/cloudlog.c b/bluesky/cloudlog.c
index e1fd44a..1cae4a5 100644 (file)
--- a/bluesky/cloudlog.c
+++ b/bluesky/cloudlog.c
@@ -86,6 +86,8 @@ BlueSkyCloudLog *bluesky_cloudlog_new(BlueSkyFS *fs)
 {
     BlueSkyCloudLog *log = g_new0(BlueSkyCloudLog, 1);
 
+    log->lock = g_mutex_new();
+    log->cond = g_cond_new();
     log->fs = fs;
     log->type = LOGTYPE_UNKNOWN;
     log->id = bluesky_cloudlog_new_id();
@@ -97,25 +99,26 @@ BlueSkyCloudLog *bluesky_cloudlog_new(BlueSkyFS *fs)
 
 void bluesky_cloudlog_ref(BlueSkyCloudLog *log)
 {
+    if (log == NULL)
+        return;
+
     g_atomic_int_inc(&log->refcount);
 }
 
 void bluesky_cloudlog_unref(BlueSkyCloudLog *log)
 {
+    if (log == NULL)
+        return;
+
     if (g_atomic_int_dec_and_test(&log->refcount)) {
         g_print("Cloud log refcount dropped to zero.\n");
     }
 }
 
 /* Start a write of the object to the local log. */
-BlueSkyLogItem *bluesky_cloudlog_sync(BlueSkyCloudLog *log)
+void bluesky_cloudlog_sync(BlueSkyCloudLog *log)
 {
-    BlueSkyLogItem *log_item = bluesky_log_item_new();
-    log_item->key = bluesky_cloudlog_id_to_string(log->id);
-    log_item->data = log->data;
-    bluesky_string_ref(log->data);
-    bluesky_log_item_submit(log_item, log->fs->log);
-    return log_item;
+    bluesky_log_item_submit(log, log->fs->log);
 }
 
 /* Add the given entry to the global hash table containing cloud log entries.
@@ -162,11 +165,15 @@ BlueSkyCloudPointer bluesky_cloudlog_serialize(BlueSkyCloudLog *log,
         BlueSkyCloudLog *log2
             = (BlueSkyCloudLog *)g_hash_table_lookup(log->fs->locations, &id);
         // TODO: refcount
-        g_mutex_unlock(log->fs->lock);
         g_assert(log2 != NULL);
+        bluesky_cloudlog_ref(log2);
+        g_mutex_unlock(log->fs->lock);
         bluesky_cloudlog_serialize(log2, state);
+        bluesky_cloudlog_unref(log2);
     }
 
+    g_mutex_lock(log->lock);
+    bluesky_cloudlog_fetch(log);
     g_assert(log->data != NULL);
 
     log->location = state->location;
@@ -185,6 +192,7 @@ BlueSkyCloudPointer bluesky_cloudlog_serialize(BlueSkyCloudLog *log,
     g_string_append_len(state->data, log->data->data, log->data->len);
 
     log->location_flags |= CLOUDLOG_CLOUD;
+    g_mutex_unlock(log->lock);
 
     return log->location;
 }
@@ -203,10 +211,9 @@ static void find_inodes(gpointer key, gpointer value, gpointer user_data)
 
 void bluesky_cloudlog_write_log(BlueSkyFS *fs)
 {
-    g_print("Starting cloudlog write...\n");
-
     BlueSkyCloudLogState *state = fs->log_state;
-    state->data = g_string_new("");
+    if (state->data == NULL)
+        state->data = g_string_new("");
 
     g_mutex_lock(fs->lock);
     g_hash_table_foreach(fs->locations, find_inodes, state);
@@ -219,19 +226,41 @@ void bluesky_cloudlog_write_log(BlueSkyFS *fs)
                                                state->inode_list);
     }
 
-    g_print("Serialized %zd bytes of data\n", state->data->len);
-
-    BlueSkyStoreAsync *async = bluesky_store_async_new(fs->store);
-    async->op = STORE_OP_PUT;
-    async->key = g_strdup_printf("log-%08d-%08d",
-                                 state->location.directory,
-                                 state->location.sequence);
-    async->data = bluesky_string_new_from_gstring(state->data);
-    bluesky_store_async_submit(async);
-    bluesky_store_async_wait(async);
-    bluesky_store_async_unref(async);
+    if (state->data->len > 0) {
+        g_print("Serialized %zd bytes of data to cloud\n", state->data->len);
+
+        BlueSkyStoreAsync *async = bluesky_store_async_new(fs->store);
+        async->op = STORE_OP_PUT;
+        async->key = g_strdup_printf("log-%08d-%08d",
+                                     state->location.directory,
+                                     state->location.sequence);
+        async->data = bluesky_string_new_from_gstring(state->data);
+        bluesky_store_async_submit(async);
+        bluesky_store_async_wait(async);
+        bluesky_store_async_unref(async);
+
+        state->location.sequence++;
+        state->location.offset = 0;
+    }
 
     state->data = NULL;
-    state->location.sequence++;
-    state->location.offset = 0;
+}
+
+/* Ensure that a cloud log item is loaded in memory, and if not read it in.
+ * TODO: Make asynchronous, and make this also fetch from the cloud.  Right now
+ * we only read from the log.  Log item must be locked. */
+void bluesky_cloudlog_fetch(BlueSkyCloudLog *log)
+{
+    if (log->data != NULL)
+        return;
+
+    g_print("Re-mapping log entry %d/%d/%d...\n",
+            log->log_seq, log->log_offset, log->log_size);
+
+    g_assert(log->location_flags & CLOUDLOG_JOURNAL);
+
+    log->data = bluesky_log_map_object(log->fs->log, log->log_seq,
+                                       log->log_offset, log->log_size);
+
+    g_cond_broadcast(log->cond);
 }