Release 4.11 drivers/md/dm-exception-store.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/ctype.h>
#include <linux/mm.h>
#include <linux/pagemap.h>
#include <linux/vmalloc.h>
#include <linux/module.h>
#include <linux/slab.h>


#define DM_MSG_PREFIX "snapshot exception stores"

static LIST_HEAD(_exception_store_types);
static DEFINE_SPINLOCK(_lock);



static struct dm_exception_store_type *__find_exception_store_type(const char *name)
{
	struct dm_exception_store_type *type;

	list_for_each_entry(type, &_exception_store_types, list)
		if (!strcmp(name, type->name))
			return type;

	return NULL;
}

Contributors
Person
Tokens
Prop
Commits
CommitProp
Jonathan E Brassow
44
100.00%
1
100.00%
Total
44
100.00%
1
100.00%



static struct dm_exception_store_type *_get_exception_store_type(const char *name)
{
	struct dm_exception_store_type *type;

	spin_lock(&_lock);

	type = __find_exception_store_type(name);

	if (type && !try_module_get(type->module))
		type = NULL;

	spin_unlock(&_lock);

	return type;
}

Contributors
Person
Tokens
Prop
Commits
CommitProp
Jonathan E Brassow
56
100.00%
1
100.00%
Total
56
100.00%
1
100.00%

/*
 * get_type
 * @type_name
 *
 * Attempt to retrieve the dm_exception_store_type by name.  If not already
 * available, attempt to load the appropriate module.
 *
 * Exstore modules are named "dm-exstore-" followed by the 'type_name'.
 * Modules may contain multiple types.
 * This function will first try the module "dm-exstore-<type_name>",
 * then truncate 'type_name' on the last '-' and try again.
 *
 * For example, if type_name was "clustered-shared", it would search
 * 'dm-exstore-clustered-shared' then 'dm-exstore-clustered'.
 *
 * 'dm-exception-store-<type_name>' is too long of a name in my
 * opinion, which is why I've chosen to have the files
 * containing exception store implementations be 'dm-exstore-<type_name>'.
 * If you want your module to be autoloaded, you will follow this
 * naming convention.
 *
 * Returns: dm_exception_store_type* on success, NULL on failure
 */


static struct dm_exception_store_type *get_type(const char *type_name)
{
	char *p, *type_name_dup;
	struct dm_exception_store_type *type;

	type = _get_exception_store_type(type_name);
	if (type)
		return type;

	type_name_dup = kstrdup(type_name, GFP_KERNEL);
	if (!type_name_dup) {
		DMERR("No memory left to attempt load for \"%s\"", type_name);
		return NULL;
	}

	while (request_module("dm-exstore-%s", type_name_dup) ||
	       !(type = _get_exception_store_type(type_name))) {
		p = strrchr(type_name_dup, '-');
		if (!p)
			break;
		p[0] = '\0';
	}

	if (!type)
		DMWARN("Module for exstore type \"%s\" not found.", type_name);

	kfree(type_name_dup);

	return type;
}

Contributors
Person
Tokens
Prop
Commits
CommitProp
Jonathan E Brassow
128
100.00%
1
100.00%
Total
128
100.00%
1
100.00%



static void put_type(struct dm_exception_store_type *type)
{
	spin_lock(&_lock);
	module_put(type->module);
	spin_unlock(&_lock);
}

Contributors
Person
Tokens
Prop
Commits
CommitProp
Jonathan E Brassow
30
100.00%
1
100.00%
Total
30
100.00%
1
100.00%



int dm_exception_store_type_register(struct dm_exception_store_type *type)
{
	int r = 0;

	spin_lock(&_lock);
	if (!__find_exception_store_type(type->name))
		list_add(&type->list, &_exception_store_types);
	else
		r = -EEXIST;
	spin_unlock(&_lock);

	return r;
}
Contributors
Person
Tokens
Prop
Commits
CommitProp
Jonathan E Brassow
57
100.00%
1
100.00%
Total
57
100.00%
1
100.00%


EXPORT_SYMBOL(dm_exception_store_type_register);



int dm_exception_store_type_unregister(struct dm_exception_store_type *type)
{
	spin_lock(&_lock);

	if (!__find_exception_store_type(type->name)) {
		spin_unlock(&_lock);
		return -EINVAL;
	}

	list_del(&type->list);

	spin_unlock(&_lock);

	return 0;
}
Contributors
Person
Tokens
Prop
Commits
CommitProp
Jonathan E Brassow
55
100.00%
1
100.00%
Total
55
100.00%
1
100.00%


EXPORT_SYMBOL(dm_exception_store_type_unregister);



static int set_chunk_size(struct dm_exception_store *store,
			  const char *chunk_size_arg, char **error)
{
	unsigned chunk_size;

	if (kstrtouint(chunk_size_arg, 10, &chunk_size)) {
		*error = "Invalid chunk size";
		return -EINVAL;
	}

	if (!chunk_size) {
		store->chunk_size = store->chunk_mask = store->chunk_shift = 0;
		return 0;
	}

	return dm_exception_store_set_chunk_size(store, chunk_size, error);
}

Contributors
Person
Tokens
Prop
Commits
CommitProp
Jonathan E Brassow
62
76.54%
2
50.00%
Mikulas Patocka
10
12.35%
1
25.00%
Jianpeng Ma (马建朋)
9
11.11%
1
25.00%
Total
81
100.00%
4
100.00%



int dm_exception_store_set_chunk_size(struct dm_exception_store *store,
				      unsigned chunk_size,
				      char **error)
{
	/* Check chunk_size is a power of 2 */
	if (!is_power_of_2(chunk_size)) {
		*error = "Chunk size is not a power of 2";
		return -EINVAL;
	}

	/* Validate the chunk size against the device block size */
	if (chunk_size %
	    (bdev_logical_block_size(dm_snap_cow(store->snap)->bdev) >> 9) ||
	    chunk_size %
	    (bdev_logical_block_size(dm_snap_origin(store->snap)->bdev) >> 9)) {
		*error = "Chunk size is not a multiple of device blocksize";
		return -EINVAL;
	}

	if (chunk_size > INT_MAX >> SECTOR_SHIFT) {
		*error = "Chunk size is too high";
		return -EINVAL;
	}

	store->chunk_size = chunk_size;
	store->chunk_mask = chunk_size - 1;
	store->chunk_shift = __ffs(chunk_size);

	return 0;
}

Contributors
Person
Tokens
Prop
Commits
CommitProp
Jonathan E Brassow
68
51.13%
1
12.50%
Mikulas Patocka
60
45.11%
5
62.50%
Mike Snitzer
4
3.01%
1
12.50%
Martin K. Petersen
1
0.75%
1
12.50%
Total
133
100.00%
8
100.00%



int dm_exception_store_create(struct dm_target *ti, int argc, char **argv,
			      struct dm_snapshot *snap,
			      unsigned *args_used,
			      struct dm_exception_store **store)
{
	int r = 0;
	struct dm_exception_store_type *type = NULL;
	struct dm_exception_store *tmp_store;
	char persistent;

	if (argc < 2) {
		ti->error = "Insufficient exception store arguments";
		return -EINVAL;
	}

	tmp_store = kzalloc(sizeof(*tmp_store), GFP_KERNEL);
	if (!tmp_store) {
		ti->error = "Exception store allocation failed";
		return -ENOMEM;
	}

	persistent = toupper(*argv[0]);
	if (persistent == 'P')
		type = get_type("P");
	else if (persistent == 'N')
		type = get_type("N");
	else {
		ti->error = "Exception store type is not P or N";
		r = -EINVAL;
		goto bad_type;
	}

	if (!type) {
		ti->error = "Exception store type not recognised";
		r = -EINVAL;
		goto bad_type;
	}

	tmp_store->type = type;
	tmp_store->snap = snap;

	r = set_chunk_size(tmp_store, argv[1], &ti->error);
	if (r)
		goto bad;

	r = type->ctr(tmp_store, (strlen(argv[0]) > 1 ? &argv[0][1] : NULL));
	if (r) {
		ti->error = "Exception store type constructor failed";
		goto bad;
	}

	*args_used = 2;
	*store = tmp_store;
	return 0;

bad:
	put_type(type);
bad_type:
	kfree(tmp_store);
	return r;
}
Contributors
Person
Tokens
Prop
Commits
CommitProp
Jonathan E Brassow
225
77.59%
5
55.56%
Mike Snitzer
36
12.41%
2
22.22%
Milan Broz
23
7.93%
1
11.11%
Julia Lawall
6
2.07%
1
11.11%
Total
290
100.00%
9
100.00%


EXPORT_SYMBOL(dm_exception_store_create);



void dm_exception_store_destroy(struct dm_exception_store *store)
{
	store->type->dtr(store);
	put_type(store->type);
	kfree(store);
}
Contributors
Person
Tokens
Prop
Commits
CommitProp
Jonathan E Brassow
31
100.00%
1
100.00%
Total
31
100.00%
1
100.00%


EXPORT_SYMBOL(dm_exception_store_destroy);



int dm_exception_store_init(void)
{
	int r;

	r = dm_transient_snapshot_init();
	if (r) {
		DMERR("Unable to register transient exception store type.");
		goto transient_fail;
	}

	r = dm_persistent_snapshot_init();
	if (r) {
		DMERR("Unable to register persistent exception store type");
		goto persistent_fail;
	}

	return 0;

persistent_fail:
	dm_transient_snapshot_exit();
transient_fail:
	return r;
}

Contributors
Person
Tokens
Prop
Commits
CommitProp
Alasdair G. Kergon
49
80.33%
3
50.00%
Milan Broz
10
16.39%
1
16.67%
Mikulas Patocka
1
1.64%
1
16.67%
Andrei Warkentin
1
1.64%
1
16.67%
Total
61
100.00%
6
100.00%



void dm_exception_store_exit(void)
{
	dm_persistent_snapshot_exit();
	dm_transient_snapshot_exit();
}
Contributors
Person
Tokens
Prop
Commits
CommitProp
Alasdair G. Kergon
13
100.00%
3
100.00%
Total
13
100.00%
3
100.00%

Overall Contributors
Person
Tokens
Prop
Commits
CommitProp
Jonathan E Brassow
795
76.59%
6
23.08%
Alasdair G. Kergon
79
7.61%
5
19.23%
Mikulas Patocka
71
6.84%
6
23.08%
Mike Snitzer
40
3.85%
2
7.69%
Milan Broz
33
3.18%
2
7.69%
Jianpeng Ma (马建朋)
9
0.87%
1
3.85%
Julia Lawall
6
0.58%
1
3.85%
Paul Gortmaker
3
0.29%
1
3.85%
Martin K. Petersen
1
0.10%
1
3.85%
Andrei Warkentin
1
0.10%
1
3.85%
Total
1038
100.00%
26
100.00%
Directory: drivers/md

Information contained on this website is for historical information purposes only and does not indicate or represent copyright ownership.