Extract exception table/cache code from dm-snap.c so that
it can be used elsewhere. I've created the new files,
dm-exception.[ch]. I chose against including this code in
this dm-exception-store.[ch] files.
Signed-off-by: Jonathan Brassow <jbrassow@redhat.com>
#include <linux/blkdev.h>
#include <linux/device-mapper.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_exception {
- struct list_head hash_list;
-
- chunk_t old_chunk;
- chunk_t new_chunk;
-};
+#include "dm-exception.h"
/*
* Abstraction to handle the meta/layout of exception stores (the
@@ -108,49 +89,6 @@ struct dm_exception_store {
};
/*
- * 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_exception *e)
-{
- return e->new_chunk >> DM_CHUNK_NUMBER_BITS;
-}
-
-static inline void dm_consecutive_chunk_count_inc(struct dm_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_exception *e)
-{
- return 0;
-}
-
-static inline void dm_consecutive_chunk_count_inc(struct dm_exception *e)
-{
-}
-
-# endif
-
-/*
* Return the number of sectors in the device.
*/
static inline sector_t get_dev_size(struct block_device *bdev)
Index: linux-2.6/drivers/md/dm-exception.c
================================================== =================
--- /dev/null
+++ linux-2.6/drivers/md/dm-exception.c
@@ -0,0 +1,163 @@
+#include <linux/device-mapper.h>
+#include "dm-exception.h"
+
+struct dm_exception_table_internal {
+ struct dm_exception_table et;
+
+ struct dm_exception *(*alloc_exception)(void *context);
+ void *alloc_context;
+
+ void (*free_exception)(struct dm_exception *e, void *context);
+ void *free_context;
+};
+
+/*
+ * Implementation of the exception hash tables.
+ * The lowest hash_shift bits of the chunk number are ignored, allowing
+ * some consecutive chunks to be grouped together.
+ */
+struct dm_exception_table *
+dm_exception_table_create(uint32_t size, unsigned hash_shift,
+ struct dm_exception *(*alloc_exception)(void *),
+ void *alloc_context,
+ void (*free_exception)(struct dm_exception *e, void *),
+ void *free_context)
+{
+ unsigned int i;
+ struct dm_exception_table_internal *eti;
+ struct dm_exception_table *et;
+
+ eti = kmalloc(sizeof(*eti), GFP_KERNEL);
+ if (!eti)
+ return NULL;
+
+ et = &eti->et;
+
+ et->hash_shift = hash_shift;
+ et->hash_mask = size - 1;
+ et->table = dm_vcalloc(size, sizeof(struct list_head));
+ if (!et->table) {
+ kfree(et);
+ return NULL;
+ }
+
+ eti->alloc_exception = alloc_exception;
+ eti->alloc_context = alloc_context;
+ eti->free_exception = free_exception;
+ eti->free_context = free_context;
+
+ for (i = 0; i < size; i++)
+ INIT_LIST_HEAD(et->table + i);
+
+ return et;
+}
+
+void dm_exception_table_destroy(struct dm_exception_table *et)
+{
+ struct dm_exception_table_internal *eti;
+ struct list_head *slot;
+ struct dm_exception *ex, *next;
+ int i, size;
+
+ eti = container_of(et, struct dm_exception_table_internal, et);
+
+ size = et->hash_mask + 1;
+ for (i = 0; i < size; i++) {
+ slot = et->table + i;
+
+ list_for_each_entry_safe(ex, next, slot, hash_list)
+ eti->free_exception(ex, eti->free_context);
+ }
+
+ vfree(et->table);
+ kfree(eti);
+}
+
+static uint32_t exception_hash(struct dm_exception_table *et, chunk_t chunk)
+{
+ return (chunk >> et->hash_shift) & et->hash_mask;
+}
+
+void dm_insert_exception(struct dm_exception_table *eh,
+ struct dm_exception *new_e)
+{
+ struct list_head *l;
+ struct dm_exception *e = NULL;
+
+ l = &eh->table[exception_hash(eh, new_e->old_chunk)];
+
+ /* Add immediately if this table doesn't support consecutive chunks */
+ if (!eh->hash_shift)
+ goto out;
+
+ /* List is ordered by old_chunk */
+ list_for_each_entry_reverse(e, l, hash_list) {
+ /* Insert after an existing chunk? */
+ if (new_e->old_chunk == (e->old_chunk +
+ dm_consecutive_chunk_count(e) + 1) &&
+ new_e->new_chunk == (dm_chunk_number(e->new_chunk) +
+ dm_consecutive_chunk_count(e) + 1)) {
+ dm_consecutive_chunk_count_inc(e);
+ dm_free_exception(eh, new_e);
+ return;
+ }
+
+ /* Insert before an existing chunk? */
+ if (new_e->old_chunk == (e->old_chunk - 1) &&
+ new_e->new_chunk == (dm_chunk_number(e->new_chunk) - 1)) {
+ dm_consecutive_chunk_count_inc(e);
+ e->old_chunk--;
+ e->new_chunk--;
+ dm_free_exception(eh, new_e);
+ return;
+ }
+
+ if (new_e->old_chunk > e->old_chunk)
+ break;
+ }
+
+out:
+ list_add(&new_e->hash_list, e ? &e->hash_list : l);
+}
+
+void dm_remove_exception(struct dm_exception *e)
+{
+ list_del(&e->hash_list);
+}
+
+/*
+ * Return the exception data for a sector, or NULL if not
+ * remapped.
+ */
+struct dm_exception *dm_lookup_exception(struct dm_exception_table *et,
+ chunk_t chunk)
+{
+ struct list_head *slot;
+ struct dm_exception *e;
+
+ slot = &et->table[exception_hash(et, chunk)];
+ list_for_each_entry(e, slot, hash_list)
+ if (chunk >= e->old_chunk &&
+ chunk <= e->old_chunk + dm_consecutive_chunk_count(e))
+ return e;
+
+ return NULL;
+}
+
+struct dm_exception *dm_alloc_exception(struct dm_exception_table *et)
+{
+ struct dm_exception_table_internal *eti;
+
+ eti = container_of(et, struct dm_exception_table_internal, et);
+
+ return eti->alloc_exception(eti->alloc_context);
+}
+
+void dm_free_exception(struct dm_exception_table *et, struct dm_exception *e)
+{
+ struct dm_exception_table_internal *eti;
+
+ eti = container_of(et, struct dm_exception_table_internal, et);
+
+ return eti->free_exception(e, eti->free_context);
+}
Index: linux-2.6/drivers/md/dm-exception.h
================================================== =================
--- /dev/null
+++ linux-2.6/drivers/md/dm-exception.h
@@ -0,0 +1,104 @@
+/*
+ * Copyright (C) 2009 Red Hat, Inc. All rights reserved.
+ *
+ * Device-mapper exception structure and associated functions.
+ *
+ * This file is released under the GPL.
+ */
+
+#ifndef __LINUX_DM_EXCEPTION__
+#define __LINUX_DM_EXCEPTION__
+
+#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_exception {
+ struct list_head hash_list;
+
+ chunk_t old_chunk;
+ chunk_t new_chunk;
+};
+
+struct dm_exception_table {
+ uint32_t hash_mask;
+ unsigned hash_shift;
+ struct list_head *table;
+};
+
+/*
+ * 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_exception *e)
+{
+ return e->new_chunk >> DM_CHUNK_NUMBER_BITS;
+}
+
+static inline void dm_consecutive_chunk_count_inc(struct dm_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_exception *e)
+{
+ return 0;
+}
+
+static inline void dm_consecutive_chunk_count_inc(struct dm_exception *e)
+{
+}
+
+# endif
+
+struct dm_exception_table *
+dm_exception_table_create(uint32_t size, unsigned hash_shift,
+ struct dm_exception *(*alloc_exception)(void *),
+ void *alloc_context,
+ void (*free_exception)(struct dm_exception *e, void *),
+ void *free_context);
+
+void dm_exception_table_destroy(struct dm_exception_table *et);
+
+void dm_insert_exception(struct dm_exception_table *eh,
+ struct dm_exception *e);
+
+void dm_remove_exception(struct dm_exception *e);
+
+struct dm_exception *dm_lookup_exception(struct dm_exception_table *et,
+ chunk_t chunk);
+
+struct dm_exception *dm_alloc_exception(struct dm_exception_table *et);
+
+void dm_free_exception(struct dm_exception_table *et, struct dm_exception *e);
+
+#endif /* __LINUX_DM_EXCEPTION__ */
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
@@ -51,12 +51,6 @@
#define DM_TRACKED_CHUNK_HASH(x) ((unsigned long)(x) &
(DM_TRACKED_CHUNK_HASH_SIZE - 1))
Extract exception table/cache code from dm-snap.c so that
it can be used elsewhere. I've created the new files,
dm-exception.[ch]. I chose against including this code in
this dm-exception-store.[ch] files.
Signed-off-by: Jonathan Brassow <jbrassow@redhat.com>
#include <linux/blkdev.h>
#include <linux/device-mapper.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_exception {
- struct list_head hash_list;
-
- chunk_t old_chunk;
- chunk_t new_chunk;
-};
+#include "dm-exception.h"
/*
* Abstraction to handle the meta/layout of exception stores (the
@@ -109,49 +90,6 @@ struct dm_exception_store {
};
/*
- * 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_exception *e)
-{
- return e->new_chunk >> DM_CHUNK_NUMBER_BITS;
-}
-
-static inline void dm_consecutive_chunk_count_inc(struct dm_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_exception *e)
-{
- return 0;
-}
-
-static inline void dm_consecutive_chunk_count_inc(struct dm_exception *e)
-{
-}
-
-# endif
-
-/*
* Return the number of sectors in the device.
*/
static inline sector_t get_dev_size(struct block_device *bdev)
Index: linux-2.6/drivers/md/dm-exception.c
================================================== =================
--- /dev/null
+++ linux-2.6/drivers/md/dm-exception.c
@@ -0,0 +1,163 @@
+#include <linux/device-mapper.h>
+#include "dm-exception.h"
+
+struct dm_exception_table_internal {
+ struct dm_exception_table et;
+
+ struct dm_exception *(*alloc_exception)(void *context);
+ void *alloc_context;
+
+ void (*free_exception)(struct dm_exception *e, void *context);
+ void *free_context;
+};
+
+/*
+ * Implementation of the exception hash tables.
+ * The lowest hash_shift bits of the chunk number are ignored, allowing
+ * some consecutive chunks to be grouped together.
+ */
+struct dm_exception_table *
+dm_exception_table_create(uint32_t size, unsigned hash_shift,
+ struct dm_exception *(*alloc_exception)(void *),
+ void *alloc_context,
+ void (*free_exception)(struct dm_exception *e, void *),
+ void *free_context)
+{
+ unsigned int i;
+ struct dm_exception_table_internal *eti;
+ struct dm_exception_table *et;
+
+ eti = kmalloc(sizeof(*eti), GFP_KERNEL);
+ if (!eti)
+ return NULL;
+
+ et = &eti->et;
+
+ et->hash_shift = hash_shift;
+ et->hash_mask = size - 1;
+ et->table = dm_vcalloc(size, sizeof(struct list_head));
+ if (!et->table) {
+ kfree(et);
+ return NULL;
+ }
+
+ eti->alloc_exception = alloc_exception;
+ eti->alloc_context = alloc_context;
+ eti->free_exception = free_exception;
+ eti->free_context = free_context;
+
+ for (i = 0; i < size; i++)
+ INIT_LIST_HEAD(et->table + i);
+
+ return et;
+}
+
+void dm_exception_table_destroy(struct dm_exception_table *et)
+{
+ struct dm_exception_table_internal *eti;
+ struct list_head *slot;
+ struct dm_exception *ex, *next;
+ int i, size;
+
+ eti = container_of(et, struct dm_exception_table_internal, et);
+
+ size = et->hash_mask + 1;
+ for (i = 0; i < size; i++) {
+ slot = et->table + i;
+
+ list_for_each_entry_safe(ex, next, slot, hash_list)
+ eti->free_exception(ex, eti->free_context);
+ }
+
+ vfree(et->table);
+ kfree(eti);
+}
+
+static uint32_t exception_hash(struct dm_exception_table *et, chunk_t chunk)
+{
+ return (chunk >> et->hash_shift) & et->hash_mask;
+}
+
+void dm_insert_exception(struct dm_exception_table *eh,
+ struct dm_exception *new_e)
+{
+ struct list_head *l;
+ struct dm_exception *e = NULL;
+
+ l = &eh->table[exception_hash(eh, new_e->old_chunk)];
+
+ /* Add immediately if this table doesn't support consecutive chunks */
+ if (!eh->hash_shift)
+ goto out;
+
+ /* List is ordered by old_chunk */
+ list_for_each_entry_reverse(e, l, hash_list) {
+ /* Insert after an existing chunk? */
+ if (new_e->old_chunk == (e->old_chunk +
+ dm_consecutive_chunk_count(e) + 1) &&
+ new_e->new_chunk == (dm_chunk_number(e->new_chunk) +
+ dm_consecutive_chunk_count(e) + 1)) {
+ dm_consecutive_chunk_count_inc(e);
+ dm_free_exception(eh, new_e);
+ return;
+ }
+
+ /* Insert before an existing chunk? */
+ if (new_e->old_chunk == (e->old_chunk - 1) &&
+ new_e->new_chunk == (dm_chunk_number(e->new_chunk) - 1)) {
+ dm_consecutive_chunk_count_inc(e);
+ e->old_chunk--;
+ e->new_chunk--;
+ dm_free_exception(eh, new_e);
+ return;
+ }
+
+ if (new_e->old_chunk > e->old_chunk)
+ break;
+ }
+
+out:
+ list_add(&new_e->hash_list, e ? &e->hash_list : l);
+}
+
+void dm_remove_exception(struct dm_exception *e)
+{
+ list_del(&e->hash_list);
+}
+
+/*
+ * Return the exception data for a sector, or NULL if not
+ * remapped.
+ */
+struct dm_exception *dm_lookup_exception(struct dm_exception_table *et,
+ chunk_t chunk)
+{
+ struct list_head *slot;
+ struct dm_exception *e;
+
+ slot = &et->table[exception_hash(et, chunk)];
+ list_for_each_entry(e, slot, hash_list)
+ if (chunk >= e->old_chunk &&
+ chunk <= e->old_chunk + dm_consecutive_chunk_count(e))
+ return e;
+
+ return NULL;
+}
+
+struct dm_exception *dm_alloc_exception(struct dm_exception_table *et)
+{
+ struct dm_exception_table_internal *eti;
+
+ eti = container_of(et, struct dm_exception_table_internal, et);
+
+ return eti->alloc_exception(eti->alloc_context);
+}
+
+void dm_free_exception(struct dm_exception_table *et, struct dm_exception *e)
+{
+ struct dm_exception_table_internal *eti;
+
+ eti = container_of(et, struct dm_exception_table_internal, et);
+
+ return eti->free_exception(e, eti->free_context);
+}
Index: linux-2.6/drivers/md/dm-exception.h
================================================== =================
--- /dev/null
+++ linux-2.6/drivers/md/dm-exception.h
@@ -0,0 +1,104 @@
+/*
+ * Copyright (C) 2009 Red Hat, Inc. All rights reserved.
+ *
+ * Device-mapper exception structure and associated functions.
+ *
+ * This file is released under the GPL.
+ */
+
+#ifndef __LINUX_DM_EXCEPTION__
+#define __LINUX_DM_EXCEPTION__
+
+#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_exception {
+ struct list_head hash_list;
+
+ chunk_t old_chunk;
+ chunk_t new_chunk;
+};
+
+struct dm_exception_table {
+ uint32_t hash_mask;
+ unsigned hash_shift;
+ struct list_head *table;
+};
+
+/*
+ * 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_exception *e)
+{
+ return e->new_chunk >> DM_CHUNK_NUMBER_BITS;
+}
+
+static inline void dm_consecutive_chunk_count_inc(struct dm_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_exception *e)
+{
+ return 0;
+}
+
+static inline void dm_consecutive_chunk_count_inc(struct dm_exception *e)
+{
+}
+
+# endif
+
+struct dm_exception_table *
+dm_exception_table_create(uint32_t size, unsigned hash_shift,
+ struct dm_exception *(*alloc_exception)(void *),
+ void *alloc_context,
+ void (*free_exception)(struct dm_exception *e, void *),
+ void *free_context);
+
+void dm_exception_table_destroy(struct dm_exception_table *et);
+
+void dm_insert_exception(struct dm_exception_table *eh,
+ struct dm_exception *e);
+
+void dm_remove_exception(struct dm_exception *e);
+
+struct dm_exception *dm_lookup_exception(struct dm_exception_table *et,
+ chunk_t chunk);
+
+struct dm_exception *dm_alloc_exception(struct dm_exception_table *et);
+
+void dm_free_exception(struct dm_exception_table *et, struct dm_exception *e);
+
+#endif /* __LINUX_DM_EXCEPTION__ */
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
@@ -51,12 +51,6 @@
#define DM_TRACKED_CHUNK_HASH(x) ((unsigned long)(x) &
(DM_TRACKED_CHUNK_HASH_SIZE - 1))
DM Snapshot: move exception code to new file
