1 files changed, 131 insertions, 0 deletions
diff --git a/include/linux/dm-dirty-log.h b/include/linux/dm-dirty-log.h
new file mode 100644
index 000000000000..600c5fb2daad
--- /dev/null
+++ b/include/linux/dm-dirty-log.h
@@ -0,0 +1,131 @@
+/*
+ * Copyright (C) 2003 Sistina Software
+ * Copyright (C) 2004-2008 Red Hat, Inc. All rights reserved.
+ *
+ * Device-Mapper dirty region log.
+ *
+ * This file is released under the LGPL.
+ */
+
+#ifndef _LINUX_DM_DIRTY_LOG
+#define _LINUX_DM_DIRTY_LOG
+
+#ifdef __KERNEL__
+
+#include <linux/types.h>
+#include <linux/device-mapper.h>
+
+typedef sector_t region_t;
+
+struct dm_dirty_log_type;
+
+struct dm_dirty_log {
+	struct dm_dirty_log_type *type;
+	void *context;
+};
+
+struct dm_dirty_log_type {
+	const char *name;
+	struct module *module;
+
+	int (*ctr)(struct dm_dirty_log *log, struct dm_target *ti,
+		   unsigned argc, char **argv);
+	void (*dtr)(struct dm_dirty_log *log);
+
+	/*
+	 * There are times when we don't want the log to touch
+	 * the disk.
+	 */
+	int (*presuspend)(struct dm_dirty_log *log);
+	int (*postsuspend)(struct dm_dirty_log *log);
+	int (*resume)(struct dm_dirty_log *log);
+
+	/*
+	 * Retrieves the smallest size of region that the log can
+	 * deal with.
+	 */
+	uint32_t (*get_region_size)(struct dm_dirty_log *log);
+
+	/*
+	 * A predicate to say whether a region is clean or not.
+	 * May block.
+	 */
+	int (*is_clean)(struct dm_dirty_log *log, region_t region);
+
+	/*
+	 *  Returns: 0, 1, -EWOULDBLOCK, < 0
+	 *
+	 * A predicate function to check the area given by
+	 * [sector, sector + len) is in sync.
+	 *
+	 * If -EWOULDBLOCK is returned the state of the region is
+	 * unknown, typically this will result in a read being
+	 * passed to a daemon to deal with, since a daemon is
+	 * allowed to block.
+	 */
+	int (*in_sync)(struct dm_dirty_log *log, region_t region,
+		       int can_block);
+
+	/*
+	 * Flush the current log state (eg, to disk).  This
+	 * function may block.
+	 */
+	int (*flush)(struct dm_dirty_log *log);
+
+	/*
+	 * Mark an area as clean or dirty.  These functions may
+	 * block, though for performance reasons blocking should
+	 * be extremely rare (eg, allocating another chunk of
+	 * memory for some reason).
+	 */
+	void (*mark_region)(struct dm_dirty_log *log, region_t region);
+	void (*clear_region)(struct dm_dirty_log *log, region_t region);
+
+	/*
+	 * Returns: <0 (error), 0 (no region), 1 (region)
+	 *
+	 * The mirrord will need perform recovery on regions of
+	 * the mirror that are in the NOSYNC state.  This
+	 * function asks the log to tell the caller about the
+	 * next region that this machine should recover.
+	 *
+	 * Do not confuse this function with 'in_sync()', one
+	 * tells you if an area is synchronised, the other
+	 * assigns recovery work.
+	*/
+	int (*get_resync_work)(struct dm_dirty_log *log, region_t *region);
+
+	/*
+	 * This notifies the log that the resync status of a region
+	 * has changed.  It also clears the region from the recovering
+	 * list (if present).
+	 */
+	void (*set_region_sync)(struct dm_dirty_log *log,
+				region_t region, int in_sync);
+
+	/*
+	 * Returns the number of regions that are in sync.
+	 */
+	region_t (*get_sync_count)(struct dm_dirty_log *log);
+
+	/*
+	 * Support function for mirror status requests.
+	 */
+	int (*status)(struct dm_dirty_log *log, status_type_t status_type,
+		      char *result, unsigned maxlen);
+};
+
+int dm_dirty_log_type_register(struct dm_dirty_log_type *type);
+int dm_dirty_log_type_unregister(struct dm_dirty_log_type *type);
+
+/*
+ * Make sure you use these two functions, rather than calling
+ * type->constructor/destructor() directly.
+ */
+struct dm_dirty_log *dm_dirty_log_create(const char *type_name,
+					 struct dm_target *ti,
+					 unsigned argc, char **argv);
+void dm_dirty_log_destroy(struct dm_dirty_log *log);
+
+#endif	/* __KERNEL__ */
+#endif	/* _LINUX_DM_DIRTY_LOG_H */