From 8ea73bbfba8c53cdaf41f2abf47bec389d1fa8ba Mon Sep 17 00:00:00 2001
From: Michael Vrable <mvrable@cs.ucsd.edu>
Date: Tue, 24 Aug 2010 16:53:00 -0700
Subject: [PATCH] Update logic for flushing data to cloud.

Do not force a commit of the most recent data, and instead just write out
whatever was last written to the journal.

This could be a win or a loss:
  - We do not need to force a sync of all data to the journal when we
    upload data to the cloud.
  - But, we may end up writing out old data, which we'll then need to
    overwrite a short time later.
---
 bluesky/cache.c     |  4 ++--
 bluesky/cloudlog.c  |  2 +-
 bluesky/inode.c     | 12 +++++++-----
 bluesky/serialize.c |  4 +---
 4 files changed, 11 insertions(+), 11 deletions(-)

diff --git a/bluesky/cache.c b/bluesky/cache.c
index a9fda5b..d94c18e 100644
--- a/bluesky/cache.c
+++ b/bluesky/cache.c
@@ -132,14 +132,14 @@ static void flushd_cloud(BlueSkyFS *fs)
         g_mutex_unlock(fs->lock);
 
         g_mutex_lock(inode->lock);
-        flushd_dirty_inode(inode);
+        g_assert(inode->change_cloud == inode->change_commit);
         g_mutex_lock(fs->lock);
         bluesky_list_unlink(&fs->dirty_list, inode->dirty_list);
         inode->dirty_list = NULL;
         g_mutex_unlock(fs->lock);
 
         BlueSkyCloudLog *log = inode->committed_item;
-        bluesky_cloudlog_ref(log);
+        inode->committed_item = NULL;
         g_mutex_unlock(inode->lock);
 
         if (log != NULL)
diff --git a/bluesky/cloudlog.c b/bluesky/cloudlog.c
index a47f5b0..0356c7d 100644
--- a/bluesky/cloudlog.c
+++ b/bluesky/cloudlog.c
@@ -231,7 +231,7 @@ BlueSkyCloudPointer bluesky_cloudlog_serialize(BlueSkyCloudLog *log,
 {
     BlueSkyCloudLogState *state = fs->log_state;
 
-    if (log->location_flags & CLOUDLOG_CLOUD) {
+    if ((log->location_flags | log->pending_write) & CLOUDLOG_CLOUD) {
         return log->location;
     }
 
diff --git a/bluesky/inode.c b/bluesky/inode.c
index d284479..8748164 100644
--- a/bluesky/inode.c
+++ b/bluesky/inode.c
@@ -50,14 +50,9 @@ void bluesky_inode_update_ctime(BlueSkyInode *inode, gboolean update_mtime)
     g_mutex_lock(inode->fs->lock);
     bluesky_list_unlink(&inode->fs->unlogged_list, inode->unlogged_list);
     inode->unlogged_list = bluesky_list_prepend(&inode->fs->unlogged_list, inode);
-    bluesky_list_unlink(&inode->fs->dirty_list, inode->dirty_list);
-    inode->dirty_list = bluesky_list_prepend(&inode->fs->dirty_list, inode);
     bluesky_list_unlink(&inode->fs->accessed_list, inode->accessed_list);
     inode->accessed_list = bluesky_list_prepend(&inode->fs->accessed_list, inode);
     g_mutex_unlock(inode->fs->lock);
-
-    bluesky_cloudlog_unref(inode->committed_item);
-    inode->committed_item = NULL;
 }
 
 /* Unfortunately a glib hash table is only guaranteed to be able to store
@@ -320,6 +315,13 @@ void bluesky_inode_start_sync(BlueSkyInode *inode)
     g_mutex_lock(inode->fs->lock);
     bluesky_list_unlink(&inode->fs->unlogged_list, inode->unlogged_list);
     inode->unlogged_list = NULL;
+
+    /* Since a new version of the inode has been written to the log, also
+     * schedule a future flush of the new data to cloud storage. */
+    bluesky_list_unlink(&inode->fs->dirty_list, inode->dirty_list);
+    inode->dirty_list = bluesky_list_prepend(&inode->fs->dirty_list, inode);
+    inode->change_cloud = inode->change_count;
+
     g_mutex_unlock(inode->fs->lock);
 }
 
diff --git a/bluesky/serialize.c b/bluesky/serialize.c
index 6eef425..bee9122 100644
--- a/bluesky/serialize.c
+++ b/bluesky/serialize.c
@@ -99,9 +99,7 @@ BlueSkyCloudLog *bluesky_serialize_inode(BlueSkyInode *inode)
         g_string_append_len(out, (gchar *)&size, sizeof(uint64_t));
         for (int i = 0; i < inode->blocks->len; i++) {
             BlueSkyBlock *b = &g_array_index(inode->blocks, BlueSkyBlock, i);
-            BlueSkyCloudLog *ref = NULL;
-            if (b->type == BLUESKY_BLOCK_REF)
-                ref = b->ref;
+            BlueSkyCloudLog *ref = (b->type == BLUESKY_BLOCK_REF ? b->ref : NULL);
             bluesky_cloudlog_ref(ref);
             g_array_append_val(cloudlog->links, ref);
         }
-- 
2.20.1