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-   Device-mapper Development (http://www.linux-archive.org/device-mapper-development/)
-   -   DM Snapshot: move exception code to new file (http://www.linux-archive.org/device-mapper-development/266461-dm-snapshot-move-exception-code-new-file.html)

Jonathan Brassow 03-19-2009 08:34 PM

DM Snapshot: move exception code to new file
 
Patch name: dm-snap-move-exception-code-to-new-file.patch

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>

Index: linux-2.6/drivers/md/dm-exception-store.h
================================================== =================
--- linux-2.6.orig/drivers/md/dm-exception-store.h
+++ linux-2.6/drivers/md/dm-exception-store.h
@@ -12,26 +12,7 @@

#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))

-struct dm_exception_table {
- uint32_t hash_mask;
- unsigned hash_shift;
- struct list_head *table;
-};
-
struct dm_snapshot {
struct rw_semaphore lock;

@@ -343,126 +337,6 @@ static void unregister_snapshot(struct d
up_write(&_origins_lock);
}

-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.
- */
-static 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;
-}
-
-static 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;
-}
-
-static 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.
- */
-static 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;
-}
-
-static 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);
-}
-
-static 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);
-}
-
static struct dm_exception *alloc_completed_exception(void *unused)
{
struct dm_exception *e;
@@ -504,48 +378,6 @@ static void free_pending_exception(struc
atomic_dec(&s->pending_exceptions_count);
}

-static 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);
-}
-
/*
* Callback used by the exception stores to load exceptions when
* initialising.
Index: linux-2.6/drivers/md/Makefile
================================================== =================
--- linux-2.6.orig/drivers/md/Makefile
+++ linux-2.6/drivers/md/Makefile
@@ -5,8 +5,8 @@
dm-mod-objs := dm.o dm-table.o dm-target.o dm-linear.o dm-stripe.o
dm-ioctl.o dm-io.o dm-kcopyd.o dm-sysfs.o
dm-multipath-objs := dm-path-selector.o dm-mpath.o
-dm-snapshot-objs := dm-snap.o dm-exception-store.o dm-snap-transient.o
- dm-snap-persistent.o
+dm-snapshot-objs := dm-snap.o dm-exception.o dm-exception-store.o
+ dm-snap-persistent.o dm-snap-transient.o
dm-mirror-objs := dm-raid1.o
dm-log-clustered-objs := dm-log-cluster.o dm-log-cluster-transfer.o
md-mod-objs := md.o bitmap.o

--
dm-devel mailing list
dm-devel@redhat.com
https://www.redhat.com/mailman/listinfo/dm-devel

Jonathan Brassow 03-25-2009 08:36 PM

DM Snapshot: move exception code to new file
 
Patch name: dm-snap-move-exception-code-to-new-file.patch

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>

Index: linux-2.6/drivers/md/dm-exception-store.h
================================================== =================
--- linux-2.6.orig/drivers/md/dm-exception-store.h
+++ linux-2.6/drivers/md/dm-exception-store.h
@@ -12,26 +12,7 @@

#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))

-struct dm_exception_table {
- uint32_t hash_mask;
- unsigned hash_shift;
- struct list_head *table;
-};
-
struct dm_snapshot {
struct rw_semaphore lock;

@@ -343,126 +337,6 @@ static void unregister_snapshot(struct d
up_write(&_origins_lock);
}

-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.
- */
-static 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;
-}
-
-static 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;
-}
-
-static 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.
- */
-static 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;
-}
-
-static 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);
-}
-
-static 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);
-}
-
static struct dm_exception *alloc_completed_exception(void *unused)
{
struct dm_exception *e;
@@ -504,48 +378,6 @@ static void free_pending_exception(struc
atomic_dec(&s->pending_exceptions_count);
}

-static 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);
-}
-
/*
* Callback used by the exception stores to load exceptions when
* initialising.
Index: linux-2.6/drivers/md/Makefile
================================================== =================
--- linux-2.6.orig/drivers/md/Makefile
+++ linux-2.6/drivers/md/Makefile
@@ -5,8 +5,8 @@
dm-mod-objs := dm.o dm-table.o dm-target.o dm-linear.o dm-stripe.o
dm-ioctl.o dm-io.o dm-kcopyd.o dm-sysfs.o
dm-multipath-objs := dm-path-selector.o dm-mpath.o
-dm-snapshot-objs := dm-snap.o dm-exception-store.o dm-snap-transient.o
- dm-snap-persistent.o
+dm-snapshot-objs := dm-snap.o dm-exception.o dm-exception-store.o
+ dm-snap-persistent.o dm-snap-transient.o
dm-mirror-objs := dm-raid1.o
md-mod-objs := md.o bitmap.o
raid456-objs := raid5.o raid6algos.o raid6recov.o raid6tables.o

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