Rework cache flushing logic--this version should work much better.

[bluesky.git] / bluesky / bluesky.h

diff --git a/bluesky/bluesky.h b/bluesky/bluesky.h
index fdc2e39..714ec55 100644 (file)
--- a/bluesky/bluesky.h
+++ b/bluesky/bluesky.h
@@ -116,6 +116,22 @@ typedef struct {
     uint64_t next_inum;         /* Next available inode for allocation */
 
     BlueSkyStore *store;
+
+    /* Accounting for memory used for caches.  Space is measured in blocks, not
+     * bytes.  We track both total data in the caches and dirty data (total
+     * data includes dirty data).  Updates to these variables must be made
+     * atomically. */
+    gint cache_total, cache_dirty;
+
+    /* Linked list of inodes, sorted by access/modification times for cache
+     * management.  Editing these lists is protected by the filesystem lock; to
+     * avoid deadlock do not attempt to take any other locks while the FS lock
+     * is held for list editing purposes.  Items at the head of the list are
+     * most recently accessed/modified. */
+    GList dirty_list, accessed_list;
+
+    /* Mutex for the flush daemon, to prevent concurrent execution. */
+    GMutex *flushd_lock;
 } BlueSkyFS;
 
 /* Inode number of the root directory. */
@@ -179,6 +195,12 @@ typedef struct {
     /* Additional state for tracking cache writeback status. */
     uint64_t change_pending;    /* change_count version currently being committed to storage */
 
+    /* Pointers to the linked-list elements for this inode in the accessed and
+     * dirty linked lists.  We re-use the GList structure, using ->next to
+     * point to the head of the list and ->prev to point to the tail.  The data
+     * element is unused. */
+    GList *accessed_list, *dirty_list;
+
     int64_t atime;              /* Microseconds since the Unix epoch */
     int64_t ctime;
     int64_t mtime;
@@ -264,6 +286,7 @@ gint bluesky_dirent_compare(gconstpointer a, gconstpointer b,
                             gpointer unused);
 
 void bluesky_flushd_invoke(BlueSkyFS *fs);
+void bluesky_flushd_invoke_conditional(BlueSkyFS *fs);
 void bluesky_inode_do_sync(BlueSkyInode *inode);
 
 void bluesky_debug_dump(BlueSkyFS *fs);