mirror of
https://github.com/torvalds/linux.git
synced 2024-10-31 01:01:52 +00:00
b2a1146529
Introduce struct dm_exception_store_type. Signed-off-by: Jonathan Brassow <jbrassow@redhat.com> Signed-off-by: Alasdair G Kergon <agk@redhat.com>
99 lines
2.4 KiB
C
99 lines
2.4 KiB
C
/*
|
|
* 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 "dm-snap.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_destroy(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->snap->cow->bdev);
|
|
|
|
if (size < (tc->next_free + store->snap->chunk_size))
|
|
return -1;
|
|
|
|
e->new_chunk = sector_to_chunk(store->snap, tc->next_free);
|
|
tc->next_free += store->snap->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->snap->cow->bdev);
|
|
}
|
|
|
|
int dm_create_transient(struct dm_exception_store *store)
|
|
{
|
|
struct transient_c *tc;
|
|
|
|
store->type.dtr = transient_destroy;
|
|
store->type.read_metadata = transient_read_metadata;
|
|
store->type.prepare_exception = transient_prepare_exception;
|
|
store->type.commit_exception = transient_commit_exception;
|
|
store->type.drop_snapshot = NULL;
|
|
store->type.fraction_full = transient_fraction_full;
|
|
|
|
tc = kmalloc(sizeof(struct transient_c), GFP_KERNEL);
|
|
if (!tc)
|
|
return -ENOMEM;
|
|
|
|
tc->next_free = 0;
|
|
store->context = tc;
|
|
|
|
return 0;
|
|
}
|
|
|
|
int dm_transient_snapshot_init(void)
|
|
{
|
|
return 0;
|
|
}
|
|
|
|
void dm_transient_snapshot_exit(void)
|
|
{
|
|
}
|