Preparatory work before implementing proper cloud writing.

[bluesky.git] / bluesky / cache.c

diff --git a/bluesky/cache.c b/bluesky/cache.c
index 6a91873..441e6c4 100644 (file)
--- a/bluesky/cache.c
+++ b/bluesky/cache.c
@@ -15,7 +15,12 @@
 
 #define WRITEBACK_DELAY (20 * 1000000)
 
-/* Filesystem caching and cache coherency. */
+/* Filesystem caching and cache coherency.  There are actually a couple of
+ * different tasks that are performed here:
+ *   - Forcing data to the log if needed to reclaim memory or simply if the
+ *     data has been dirty in memory long enough.
+ *   - Writing batches of data to the cloud.
+ */
 
 static void writeback_complete(gpointer a, gpointer i)
 {
@@ -42,86 +47,6 @@ static void writeback_complete(gpointer a, gpointer i)
     g_mutex_unlock(inode->lock);
 }
 
-#if 0
-static void flushd_inode(gpointer value, gpointer user_data)
-{
-    BlueSkyFS *fs = (BlueSkyFS *)user_data;
-
-    BlueSkyInode *inode = (BlueSkyInode *)value;
-
-    g_mutex_lock(inode->lock);
-
-    if (inode->change_count == inode->change_commit) {
-        uint64_t delay = bluesky_get_current_time() - inode->access_time;
-        if (delay >= CACHE_CLEAN_DELAY) {
-            drop_caches(inode);
-
-            /* If the only references are the one we hold and the one in the
-             * filesystem inum->inode hash table...  First check the refcount
-             * without the lock for speed, but if the check looks good verify
-             * it after taking the filesystem lock. */
-            if (inode->refcount == 2) {
-                g_mutex_lock(fs->lock);
-                if (inode->refcount == 2) {
-                    g_log("bluesky/flushd", G_LOG_LEVEL_DEBUG,
-                          "Trying to drop inode %"PRIu64" from cache",
-                          inode->inum);
-                    if (g_hash_table_remove(fs->inodes, &inode->inum))
-                        bluesky_inode_unref(inode);
-                }
-                bluesky_list_unlink(&inode->fs->accessed_list,
-                                    inode->accessed_list);
-                inode->accessed_list = NULL;
-                bluesky_list_unlink(&inode->fs->dirty_list,
-                                    inode->dirty_list);
-                inode->dirty_list = NULL;
-                g_mutex_unlock(fs->lock);
-            }
-        }
-
-        g_mutex_unlock(inode->lock);
-        bluesky_inode_unref(inode);
-        return;
-    }
-
-    if (inode->change_pending) {
-        /* Waiting for an earlier writeback to finish, so don't start a new
-         * writeback yet. */
-        g_mutex_unlock(inode->lock);
-        bluesky_inode_unref(inode);
-        return;
-    }
-
-    uint64_t elapsed = bluesky_get_current_time() - inode->change_time;
-    if (elapsed < WRITEBACK_DELAY) {
-        /* Give a bit more time before starting writeback. */
-        g_mutex_unlock(inode->lock);
-        bluesky_inode_unref(inode);
-        return;
-    }
-
-    inode->change_pending = inode->change_count;
-
-    g_log("bluesky/flushd", G_LOG_LEVEL_DEBUG,
-          "Starting flush of inode %"PRIu64, inode->inum);
-
-    /* Create a store barrier.  All operations part of the writeback will be
-     * added to this barrier, so when the barrier completes we know that the
-     * writeback is finished. */
-    BlueSkyStoreAsync *barrier = bluesky_store_async_new(fs->store);
-    barrier->op = STORE_OP_BARRIER;
-
-    bluesky_inode_start_sync(inode, barrier);
-
-    bluesky_store_async_add_notifier(barrier, writeback_complete, inode);
-    bluesky_store_async_submit(barrier);
-    bluesky_store_async_unref(barrier);
-
-    g_mutex_unlock(inode->lock);
-    bluesky_inode_unref(inode);
-}
-#endif
-
 static void flushd_dirty_inode(BlueSkyInode *inode)
 {
     BlueSkyFS *fs = inode->fs;
@@ -269,8 +194,8 @@ static gpointer flushd_task(BlueSkyFS *fs)
     if (!g_mutex_trylock(fs->flushd_lock))
         return NULL;
     flushd_dirty(fs);
-    flushd_clean(fs);
     bluesky_cloudlog_write_log(fs);
+    flushd_clean(fs);
     g_mutex_unlock(fs->flushd_lock);
 
     return NULL;