Fix a bug in committing of dirty inodes to stable storage.

[bluesky.git] / bluesky / cache.c

diff --git a/bluesky/cache.c b/bluesky/cache.c
index 979c917..1f10db0 100644 (file)
--- a/bluesky/cache.c
+++ b/bluesky/cache.c
@@ -14,6 +14,7 @@
 #include "bluesky-private.h"
 
 #define WRITEBACK_DELAY (5 * 1000000)
+#define CACHE_CLEAN_DELAY (30 * 1000000)
 
 /* Filesystem caching and cache coherency. */
 
@@ -27,15 +28,22 @@ static void writeback_complete(gpointer a, gpointer i)
     g_mutex_lock(inode->lock);
 
     inode->change_commit = inode->change_pending;
+    inode->change_pending = 0;
     if (inode->change_count == inode->change_commit) {
         /* If inode is no longer dirty... */
         inode->change_time = 0;
-        inode->change_pending = 0;
     }
 
     g_mutex_unlock(inode->lock);
 }
 
+/* Drop cached data for a given inode, if it is clean.  inode must be locked. */
+static void drop_caches(BlueSkyInode *inode)
+{
+    if (inode->type == BLUESKY_REGULAR)
+        bluesky_file_drop_cached(inode);
+}
+
 static void flushd_inode(gpointer value, gpointer user_data)
 {
     BlueSkyFS *fs = (BlueSkyFS *)user_data;
@@ -45,6 +53,27 @@ static void flushd_inode(gpointer value, gpointer user_data)
     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);
+                }
+                g_mutex_unlock(fs->lock);
+            }
+        }
+
         g_mutex_unlock(inode->lock);
         bluesky_inode_unref(inode);
         return;