Work to allow mmap-ed log entries to be used for data blocks.

[bluesky.git] / bluesky / cloudlog.c

diff --git a/bluesky/cloudlog.c b/bluesky/cloudlog.c
index 82f0f65..d7cea63 100644 (file)
--- a/bluesky/cloudlog.c
+++ b/bluesky/cloudlog.c
@@ -99,11 +99,17 @@ 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");
     }
@@ -203,7 +209,8 @@ 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);
@@ -216,19 +223,39 @@ 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\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);
 }