mirror of
https://github.com/torvalds/linux.git
synced 2024-11-05 03:21:32 +00:00
fc56f6fbcc
Store the reference to the snapshot cow device in the core snapshot code instead of each exception store. It can be accessed through the new function dm_snap_cow(). Exception stores should each now maintain a reference to their parent snapshot struct. This is cleaner and makes part of the forthcoming snapshot merge code simpler. Signed-off-by: Mike Snitzer <snitzer@redhat.com> Signed-off-by: Alasdair G Kergon <agk@redhat.com> Reviewed-by: Jonathan Brassow <jbrassow@redhat.com> Cc: Mikulas Patocka <mpatocka@redhat.com>
153 lines
3.6 KiB
C
153 lines
3.6 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 <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_exception *e)
|
|
{
|
|
struct transient_c *tc = store->context;
|
|
sector_t size = get_dev_size(dm_snap_cow(store->snap)->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_exception *e,
|
|
void (*callback) (void *, int success),
|
|
void *callback_context)
|
|
{
|
|
/* Just succeed */
|
|
callback(callback_context, 1);
|
|
}
|
|
|
|
static void transient_usage(struct dm_exception_store *store,
|
|
sector_t *total_sectors,
|
|
sector_t *sectors_allocated,
|
|
sector_t *metadata_sectors)
|
|
{
|
|
*sectors_allocated = ((struct transient_c *) store->context)->next_free;
|
|
*total_sectors = get_dev_size(dm_snap_cow(store->snap)->bdev);
|
|
*metadata_sectors = 0;
|
|
}
|
|
|
|
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(" N %llu", (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,
|
|
.usage = transient_usage,
|
|
.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,
|
|
.usage = transient_usage,
|
|
.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);
|
|
}
|