1 files changed, 65 insertions, 0 deletions
diff --git a/fs/btrfs/ulist.h b/fs/btrfs/ulist.h
new file mode 100644
index 00000000000..7f78cbf5cf4
--- /dev/null
+++ b/fs/btrfs/ulist.h
@@ -0,0 +1,65 @@
+/*
+ * Copyright (C) 2011 STRATO AG
+ * written by Arne Jansen <sensille@gmx.net>
+ * Distributed under the GNU GPL license version 2.
+ *
+ */
+
+#ifndef __ULIST__
+#define __ULIST__
+
+#include <linux/list.h>
+#include <linux/rbtree.h>
+
+/*
+ * ulist is a generic data structure to hold a collection of unique u64
+ * values. The only operations it supports is adding to the list and
+ * enumerating it.
+ * It is possible to store an auxiliary value along with the key.
+ *
+ */
+struct ulist_iterator {
+#ifdef CONFIG_BTRFS_DEBUG
+	int i;
+#endif
+	struct list_head *cur_list;  /* hint to start search */
+};
+
+/*
+ * element of the list
+ */
+struct ulist_node {
+	u64 val;		/* value to store */
+	u64 aux;		/* auxiliary value saved along with the val */
+
+#ifdef CONFIG_BTRFS_DEBUG
+	int seqnum;		/* sequence number this node is added */
+#endif
+
+	struct list_head list;  /* used to link node */
+	struct rb_node rb_node;	/* used to speed up search */
+};
+
+struct ulist {
+	/*
+	 * number of elements stored in list
+	 */
+	unsigned long nnodes;
+
+	struct list_head nodes;
+	struct rb_root root;
+};
+
+void ulist_init(struct ulist *ulist);
+void ulist_reinit(struct ulist *ulist);
+struct ulist *ulist_alloc(gfp_t gfp_mask);
+void ulist_free(struct ulist *ulist);
+int ulist_add(struct ulist *ulist, u64 val, u64 aux, gfp_t gfp_mask);
+int ulist_add_merge(struct ulist *ulist, u64 val, u64 aux,
+		    u64 *old_aux, gfp_t gfp_mask);
+struct ulist_node *ulist_next(struct ulist *ulist,
+			      struct ulist_iterator *uiter);
+
+#define ULIST_ITER_INIT(uiter) ((uiter)->cur_list = NULL)
+
+#endif