#define _LINUX_DM_EXCEPTION_STORE
#include <linux/blkdev.h>
+#include <linux/device-mapper.h>
/*
* The snapshot code deals with largish chunks of the disk at a
* Abstraction to handle the meta/layout of exception stores (the
* COW device).
*/
-struct dm_exception_store {
+struct dm_exception_store;
+struct dm_exception_store_type {
+ const char *name;
+ struct module *module;
+
+ int (*ctr) (struct dm_exception_store *store,
+ unsigned argc, char **argv);
/*
* Destroys this object when you've finished with it.
*/
- void (*destroy) (struct dm_exception_store *store);
+ void (*dtr) (struct dm_exception_store *store);
/*
* The target shouldn't read the COW device until this is
- * called.
+ * called. As exceptions are read from the COW, they are
+ * reported back via the callback.
*/
- int (*read_metadata) (struct dm_exception_store *store);
+ int (*read_metadata) (struct dm_exception_store *store,
+ int (*callback)(void *callback_context,
+ chunk_t old, chunk_t new),
+ void *callback_context);
/*
* Find somewhere to store the next exception.
*/
void (*drop_snapshot) (struct dm_exception_store *store);
+ unsigned (*status) (struct dm_exception_store *store,
+ status_type_t status, char *result,
+ unsigned maxlen);
+
/*
* Return how full the snapshot is.
*/
sector_t *numerator,
sector_t *denominator);
- struct dm_snapshot *snap;
+ /* For internal device-mapper use only. */
+ struct list_head list;
+};
+
+struct dm_exception_store {
+ struct dm_exception_store_type *type;
+ struct dm_target *ti;
+
+ struct dm_dev *cow;
+
+ /* Size of data blocks saved - must be a power of 2 */
+ unsigned chunk_size;
+ unsigned chunk_mask;
+ unsigned chunk_shift;
+
void *context;
};
/*
* Funtions to manipulate consecutive chunks
*/
-# if defined(CONFIG_LBD) || (BITS_PER_LONG == 64)
+# if defined(CONFIG_LBDAF) || (BITS_PER_LONG == 64)
# define DM_CHUNK_CONSECUTIVE_BITS 8
# define DM_CHUNK_NUMBER_BITS 56
# endif
/*
+ * Return the number of sectors in the device.
+ */
+static inline sector_t get_dev_size(struct block_device *bdev)
+{
+ return i_size_read(bdev->bd_inode) >> SECTOR_SHIFT;
+}
+
+static inline chunk_t sector_to_chunk(struct dm_exception_store *store,
+ sector_t sector)
+{
+ return sector >> store->chunk_shift;
+}
+
+int dm_exception_store_type_register(struct dm_exception_store_type *type);
+int dm_exception_store_type_unregister(struct dm_exception_store_type *type);
+
+int dm_exception_store_set_chunk_size(struct dm_exception_store *store,
+ unsigned chunk_size,
+ char **error);
+
+int dm_exception_store_create(struct dm_target *ti, int argc, char **argv,
+ unsigned *args_used,
+ struct dm_exception_store **store);
+void dm_exception_store_destroy(struct dm_exception_store *store);
+
+int dm_exception_store_init(void);
+void dm_exception_store_exit(void);
+
+/*
* Two exception store implementations.
*/
-int dm_create_persistent(struct dm_exception_store *store);
+int dm_persistent_snapshot_init(void);
+void dm_persistent_snapshot_exit(void);
-int dm_create_transient(struct dm_exception_store *store);
+int dm_transient_snapshot_init(void);
+void dm_transient_snapshot_exit(void);
#endif /* _LINUX_DM_EXCEPTION_STORE */