Make dropping of inodes from cache more resistant to races.

[bluesky.git] / bluesky / cache.c

diff --git a/bluesky/cache.c b/bluesky/cache.c
index e9d95cf..8d2cda1 100644 (file)
--- a/bluesky/cache.c
+++ b/bluesky/cache.c
@@ -54,8 +54,26 @@ static void flushd_inode(gpointer value, gpointer user_data)
 
     if (inode->change_count == inode->change_commit) {
         uint64_t delay = bluesky_get_current_time() - inode->access_time;
-        if (delay >= CACHE_CLEAN_DELAY)
+        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;