[dm-devel] [PATCH 1 of 5] dm-exception-store API
Jonathan Brassow
jbrassow at redhat.com
Thu Nov 13 10:12:22 UTC 2008
brassow
Creation of dm-exception-store.h
Pull structures that bridge the gap between snapshot and
exception store out of dm-snap.h and put them in a new
.h file - dm-exception-store.h. This file will define the
API for new exception stores.
Ultimately, dm-snap.h is unnecessary, since only dm-snap.c
should be using it.
Signed-off-by: Jonathan Brassow <jbrassow at redhat.com>
Index: linux-2.6/drivers/md/dm-exception-store.c
===================================================================
--- linux-2.6.orig/drivers/md/dm-exception-store.c
+++ linux-2.6/drivers/md/dm-exception-store.c
@@ -7,6 +7,7 @@
* This file is released under the GPL.
*/
+#include "dm-exception-store.h"
#include "dm-snap.h"
#include <linux/mm.h>
Index: linux-2.6/drivers/md/dm-exception-store.h
===================================================================
--- /dev/null
+++ linux-2.6/drivers/md/dm-exception-store.h
@@ -0,0 +1,131 @@
+/*
+ * Copyright (C) 2008 Red Hat, Inc. All rights reserved.
+ *
+ * Device-mapper exception store.
+ *
+ * This file is released under the GPL.
+ */
+
+#ifndef _LINUX_DM_EXCEPTION_STORE
+#define _LINUX_DM_EXCEPTION_STORE
+
+#include <linux/blkdev.h>
+
+/*
+ * The snapshot code deals with largish chunks of the disk at a
+ * time. Typically 32k - 512k.
+ */
+typedef sector_t chunk_t;
+
+/*
+ * An exception is used where an old chunk of data has been
+ * replaced by a new one.
+ * If chunk_t is 64 bits in size, the top 8 bits of new_chunk hold the number
+ * of chunks that follow contiguously. Remaining bits hold the number of the
+ * chunk within the device.
+ */
+struct dm_snap_exception {
+ struct list_head hash_list;
+
+ chunk_t old_chunk;
+ chunk_t new_chunk;
+};
+
+/*
+ * Abstraction to handle the meta/layout of exception stores (the
+ * COW device).
+ */
+struct exception_store {
+
+ /*
+ * Destroys this object when you've finished with it.
+ */
+ void (*destroy) (struct exception_store *store);
+
+ /*
+ * The target shouldn't read the COW device until this is
+ * called.
+ */
+ int (*read_metadata) (struct exception_store *store);
+
+ /*
+ * Find somewhere to store the next exception.
+ */
+ int (*prepare_exception) (struct exception_store *store,
+ struct dm_snap_exception *e);
+
+ /*
+ * Update the metadata with this exception.
+ */
+ void (*commit_exception) (struct exception_store *store,
+ struct dm_snap_exception *e,
+ void (*callback) (void *, int success),
+ void *callback_context);
+
+ /*
+ * The snapshot is invalid, note this in the metadata.
+ */
+ void (*drop_snapshot) (struct exception_store *store);
+
+ /*
+ * Return how full the snapshot is.
+ */
+ void (*fraction_full) (struct exception_store *store,
+ sector_t *numerator,
+ sector_t *denominator);
+
+ struct dm_snapshot *snap;
+ void *context;
+};
+
+/*
+ * Funtions to manipulate consecutive chunks
+ */
+# if defined(CONFIG_LBD) || (BITS_PER_LONG == 64)
+# define DM_CHUNK_CONSECUTIVE_BITS 8
+# define DM_CHUNK_NUMBER_BITS 56
+
+static inline chunk_t dm_chunk_number(chunk_t chunk)
+{
+ return chunk & (chunk_t)((1ULL << DM_CHUNK_NUMBER_BITS) - 1ULL);
+}
+
+static inline unsigned dm_consecutive_chunk_count(struct dm_snap_exception *e)
+{
+ return e->new_chunk >> DM_CHUNK_NUMBER_BITS;
+}
+
+static inline void dm_consecutive_chunk_count_inc(struct dm_snap_exception *e)
+{
+ e->new_chunk += (1ULL << DM_CHUNK_NUMBER_BITS);
+
+ BUG_ON(!dm_consecutive_chunk_count(e));
+}
+
+# else
+# define DM_CHUNK_CONSECUTIVE_BITS 0
+
+static inline chunk_t dm_chunk_number(chunk_t chunk)
+{
+ return chunk;
+}
+
+static inline unsigned dm_consecutive_chunk_count(struct dm_snap_exception *e)
+{
+ return 0;
+}
+
+static inline void dm_consecutive_chunk_count_inc(struct dm_snap_exception *e)
+{
+}
+
+# endif
+
+/*
+ * Constructor and destructor for the exception stores
+ */
+int dm_create_persistent(struct exception_store *store);
+
+int dm_create_transient(struct exception_store *store);
+
+#endif /* _LINUX_DM_EXCEPTION_STORE */
Index: linux-2.6/drivers/md/dm-snap.c
===================================================================
--- linux-2.6.orig/drivers/md/dm-snap.c
+++ linux-2.6/drivers/md/dm-snap.c
@@ -20,6 +20,7 @@
#include <linux/log2.h>
#include <linux/dm-kcopyd.h>
+#include "dm-exception-store.h"
#include "dm-snap.h"
#include "dm-bio-list.h"
Index: linux-2.6/drivers/md/dm-snap.h
===================================================================
--- linux-2.6.orig/drivers/md/dm-snap.h
+++ linux-2.6/drivers/md/dm-snap.h
@@ -20,116 +20,6 @@ struct exception_table {
struct list_head *table;
};
-/*
- * The snapshot code deals with largish chunks of the disk at a
- * time. Typically 32k - 512k.
- */
-typedef sector_t chunk_t;
-
-/*
- * An exception is used where an old chunk of data has been
- * replaced by a new one.
- * If chunk_t is 64 bits in size, the top 8 bits of new_chunk hold the number
- * of chunks that follow contiguously. Remaining bits hold the number of the
- * chunk within the device.
- */
-struct dm_snap_exception {
- struct list_head hash_list;
-
- chunk_t old_chunk;
- chunk_t new_chunk;
-};
-
-/*
- * Funtions to manipulate consecutive chunks
- */
-# if defined(CONFIG_LBD) || (BITS_PER_LONG == 64)
-# define DM_CHUNK_CONSECUTIVE_BITS 8
-# define DM_CHUNK_NUMBER_BITS 56
-
-static inline chunk_t dm_chunk_number(chunk_t chunk)
-{
- return chunk & (chunk_t)((1ULL << DM_CHUNK_NUMBER_BITS) - 1ULL);
-}
-
-static inline unsigned dm_consecutive_chunk_count(struct dm_snap_exception *e)
-{
- return e->new_chunk >> DM_CHUNK_NUMBER_BITS;
-}
-
-static inline void dm_consecutive_chunk_count_inc(struct dm_snap_exception *e)
-{
- e->new_chunk += (1ULL << DM_CHUNK_NUMBER_BITS);
-
- BUG_ON(!dm_consecutive_chunk_count(e));
-}
-
-# else
-# define DM_CHUNK_CONSECUTIVE_BITS 0
-
-static inline chunk_t dm_chunk_number(chunk_t chunk)
-{
- return chunk;
-}
-
-static inline unsigned dm_consecutive_chunk_count(struct dm_snap_exception *e)
-{
- return 0;
-}
-
-static inline void dm_consecutive_chunk_count_inc(struct dm_snap_exception *e)
-{
-}
-
-# endif
-
-/*
- * Abstraction to handle the meta/layout of exception stores (the
- * COW device).
- */
-struct exception_store {
-
- /*
- * Destroys this object when you've finished with it.
- */
- void (*destroy) (struct exception_store *store);
-
- /*
- * The target shouldn't read the COW device until this is
- * called.
- */
- int (*read_metadata) (struct exception_store *store);
-
- /*
- * Find somewhere to store the next exception.
- */
- int (*prepare_exception) (struct exception_store *store,
- struct dm_snap_exception *e);
-
- /*
- * Update the metadata with this exception.
- */
- void (*commit_exception) (struct exception_store *store,
- struct dm_snap_exception *e,
- void (*callback) (void *, int success),
- void *callback_context);
-
- /*
- * The snapshot is invalid, note this in the metadata.
- */
- void (*drop_snapshot) (struct exception_store *store);
-
- /*
- * Return how full the snapshot is.
- */
- void (*fraction_full) (struct exception_store *store,
- sector_t *numerator,
- sector_t *denominator);
-
- struct dm_snapshot *snap;
- void *context;
-};
-
#define DM_TRACKED_CHUNK_HASH_SIZE 16
#define DM_TRACKED_CHUNK_HASH(x) ((unsigned long)(x) & \
(DM_TRACKED_CHUNK_HASH_SIZE - 1))
@@ -193,14 +83,6 @@ struct dm_snapshot {
int dm_add_exception(struct dm_snapshot *s, chunk_t old, chunk_t new);
/*
- * Constructor and destructor for the default persistent
- * store.
- */
-int dm_create_persistent(struct exception_store *store);
-
-int dm_create_transient(struct exception_store *store);
-
-/*
* Return the number of sectors in the device.
*/
static inline sector_t get_dev_size(struct block_device *bdev)
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