[deliverable/linux.git] / drivers / md / dm-snap-transient.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/export.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, int valid,
				       void (*callback) (void *, int success),
				       void *callback_context)
{
	/* Just succeed */
	callback(callback_context, valid);
}

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, char *options)
{
	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);
}
Commit	Line	Data
	1	/*
	2	* Copyright (C) 2001-2002 Sistina Software (UK) Limited.
	3	* Copyright (C) 2006-2008 Red Hat GmbH
	4	*
	5	* This file is released under the GPL.
	6	*/
	7
	8	#include "dm-exception-store.h"
	9
	10	#include <linux/mm.h>
	11	#include <linux/pagemap.h>
	12	#include <linux/vmalloc.h>
	13	#include <linux/export.h>
	14	#include <linux/slab.h>
	15	#include <linux/dm-io.h>
	16
	17	#define DM_MSG_PREFIX "transient snapshot"
	18
	19	/*-----------------------------------------------------------------
	20	* Implementation of the store for non-persistent snapshots.
	21	---------------------------------------------------------------/
	22	struct transient_c {
	23	sector_t next_free;
	24	};
	25
	26	static void transient_dtr(struct dm_exception_store *store)
	27	{
	28	kfree(store->context);
	29	}
	30
	31	static int transient_read_metadata(struct dm_exception_store *store,
	32	int (callback)(void callback_context,
	33	chunk_t old, chunk_t new),
	34	void *callback_context)
	35	{
	36	return 0;
	37	}
	38
	39	static int transient_prepare_exception(struct dm_exception_store *store,
	40	struct dm_exception *e)
	41	{
	42	struct transient_c *tc = store->context;
	43	sector_t size = get_dev_size(dm_snap_cow(store->snap)->bdev);
	44
	45	if (size < (tc->next_free + store->chunk_size))
	46	return -1;
	47
	48	e->new_chunk = sector_to_chunk(store, tc->next_free);
	49	tc->next_free += store->chunk_size;
	50
	51	return 0;
	52	}
	53
	54	static void transient_commit_exception(struct dm_exception_store *store,
	55	struct dm_exception *e, int valid,
	56	void (callback) (void , int success),
	57	void *callback_context)
	58	{
	59	/* Just succeed */
	60	callback(callback_context, valid);
	61	}
	62
	63	static void transient_usage(struct dm_exception_store *store,
	64	sector_t *total_sectors,
	65	sector_t *sectors_allocated,
	66	sector_t *metadata_sectors)
	67	{
	68	sectors_allocated = ((struct transient_c ) store->context)->next_free;
	69	*total_sectors = get_dev_size(dm_snap_cow(store->snap)->bdev);
	70	*metadata_sectors = 0;
	71	}
	72
	73	static int transient_ctr(struct dm_exception_store store, char options)
	74	{
	75	struct transient_c *tc;
	76
	77	tc = kmalloc(sizeof(struct transient_c), GFP_KERNEL);
	78	if (!tc)
	79	return -ENOMEM;
	80
	81	tc->next_free = 0;
	82	store->context = tc;
	83
	84	return 0;
	85	}
	86
	87	static unsigned transient_status(struct dm_exception_store *store,
	88	status_type_t status, char *result,
	89	unsigned maxlen)
	90	{
	91	unsigned sz = 0;
	92
	93	switch (status) {
	94	case STATUSTYPE_INFO:
	95	break;
	96	case STATUSTYPE_TABLE:
	97	DMEMIT(" N %llu", (unsigned long long)store->chunk_size);
	98	}
	99
	100	return sz;
	101	}
	102
	103	static struct dm_exception_store_type _transient_type = {
	104	.name = "transient",
	105	.module = THIS_MODULE,
	106	.ctr = transient_ctr,
	107	.dtr = transient_dtr,
	108	.read_metadata = transient_read_metadata,
	109	.prepare_exception = transient_prepare_exception,
	110	.commit_exception = transient_commit_exception,
	111	.usage = transient_usage,
	112	.status = transient_status,
	113	};
	114
	115	static struct dm_exception_store_type _transient_compat_type = {
	116	.name = "N",
	117	.module = THIS_MODULE,
	118	.ctr = transient_ctr,
	119	.dtr = transient_dtr,
	120	.read_metadata = transient_read_metadata,
	121	.prepare_exception = transient_prepare_exception,
	122	.commit_exception = transient_commit_exception,
	123	.usage = transient_usage,
	124	.status = transient_status,
	125	};
	126
	127	int dm_transient_snapshot_init(void)
	128	{
	129	int r;
	130
	131	r = dm_exception_store_type_register(&_transient_type);
	132	if (r) {
	133	DMWARN("Unable to register transient exception store type");
	134	return r;
	135	}
	136
	137	r = dm_exception_store_type_register(&_transient_compat_type);
	138	if (r) {
	139	DMWARN("Unable to register old-style transient "
	140	"exception store type");
	141	dm_exception_store_type_unregister(&_transient_type);
	142	return r;
	143	}
	144
	145	return r;
	146	}
	147
	148	void dm_transient_snapshot_exit(void)
	149	{
	150	dm_exception_store_type_unregister(&_transient_type);
	151	dm_exception_store_type_unregister(&_transient_compat_type);
	152	}