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/*
* Copyright (C) 2001-2002 Sistina Software (UK) Limited.
* Copyright (C) 2006-2008 Red Hat GmbH
*
* This file is released under the GPL.
*/
#include "dm-exception-store.h"
#include <linux/mm.h>
#include <linux/pagemap.h>
#include <linux/vmalloc.h>
#include <linux/slab.h>
#include <linux/dm-io.h>
#define DM_MSG_PREFIX "transient snapshot"
/*-----------------------------------------------------------------
* Implementation of the store for non-persistent snapshots.
*---------------------------------------------------------------*/
struct transient_c {
sector_t next_free;
};
static void transient_dtr(struct dm_exception_store *store)
{
kfree(store->context);
}
static int transient_read_metadata(struct dm_exception_store *store,
int (*callback)(void *callback_context,
chunk_t old, chunk_t new),
void *callback_context)
{
return 0;
}
static int transient_prepare_exception(struct dm_exception_store *store,
struct dm_snap_exception *e)
{
struct transient_c *tc = store->context;
sector_t size = get_dev_size(store->cow->bdev);
if (size < (tc->next_free + store->chunk_size))
return -1;
e->new_chunk = sector_to_chunk(store, tc->next_free);
tc->next_free += store->chunk_size;
return 0;
}
static void transient_commit_exception(struct dm_exception_store *store,
struct dm_snap_exception *e,
void (*callback) (void *, int success),
void *callback_context)
{
/* Just succeed */
callback(callback_context, 1);
}
static void transient_fraction_full(struct dm_exception_store *store,
sector_t *numerator, sector_t *denominator)
{
*numerator = ((struct transient_c *) store->context)->next_free;
*denominator = get_dev_size(store->cow->bdev);
}
static int transient_ctr(struct dm_exception_store *store,
unsigned argc, char **argv)
{
struct transient_c *tc;
tc = kmalloc(sizeof(struct transient_c), GFP_KERNEL);
if (!tc)
return -ENOMEM;
tc->next_free = 0;
store->context = tc;
return 0;
}
static unsigned transient_status(struct dm_exception_store *store,
status_type_t status, char *result,
unsigned maxlen)
{
unsigned sz = 0;
switch (status) {
case STATUSTYPE_INFO:
break;
case STATUSTYPE_TABLE:
DMEMIT(" %s N %llu", store->cow->name,
(unsigned long long)store->chunk_size);
}
return sz;
}
static struct dm_exception_store_type _transient_type = {
.name = "transient",
.module = THIS_MODULE,
.ctr = transient_ctr,
.dtr = transient_dtr,
.read_metadata = transient_read_metadata,
.prepare_exception = transient_prepare_exception,
.commit_exception = transient_commit_exception,
.fraction_full = transient_fraction_full,
.status = transient_status,
};
static struct dm_exception_store_type _transient_compat_type = {
.name = "N",
.module = THIS_MODULE,
.ctr = transient_ctr,
.dtr = transient_dtr,
.read_metadata = transient_read_metadata,
.prepare_exception = transient_prepare_exception,
.commit_exception = transient_commit_exception,
.fraction_full = transient_fraction_full,
.status = transient_status,
};
int dm_transient_snapshot_init(void)
{
int r;
r = dm_exception_store_type_register(&_transient_type);
if (r) {
DMWARN("Unable to register transient exception store type");
return r;
}
r = dm_exception_store_type_register(&_transient_compat_type);
if (r) {
DMWARN("Unable to register old-style transient "
"exception store type");
dm_exception_store_type_unregister(&_transient_type);
return r;
}
return r;
}
void dm_transient_snapshot_exit(void)
{
dm_exception_store_type_unregister(&_transient_type);
dm_exception_store_type_unregister(&_transient_compat_type);
}
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