path: root/drivers/md/dm-raid.c

/*
 * Copyright (C) 2010-2011 Neil Brown
 * Copyright (C) 2010-2011 Red Hat, Inc. All rights reserved.
 *
 * This file is released under the GPL.
 */

#include <linux/slab.h>

#include "md.h"
#include "raid1.h"
#include "raid5.h"
#include "bitmap.h"

#include <linux/device-mapper.h>

#define DM_MSG_PREFIX "raid"

/*
 * The following flags are used by dm-raid.c to set up the array state.
 * They must be cleared before md_run is called.
 */
#define FirstUse 10             /* rdev flag */

struct raid_dev {
	/*
	 * Two DM devices, one to hold metadata and one to hold the
	 * actual data/parity.  The reason for this is to not confuse
	 * ti->len and give more flexibility in altering size and
	 * characteristics.
	 *
	 * While it is possible for this device to be associated
	 * with a different physical device than the data_dev, it
	 * is intended for it to be the same.
	 *    |--------- Physical Device ---------|
	 *    |- meta_dev -|------ data_dev ------|
	 */
	struct dm_dev *meta_dev;
	struct dm_dev *data_dev;
	struct md_rdev rdev;
};

/*
 * Flags for rs->print_flags field.
 */
#define DMPF_SYNC              0x1
#define DMPF_NOSYNC            0x2
#define DMPF_REBUILD           0x4
#define DMPF_DAEMON_SLEEP      0x8
#define DMPF_MIN_RECOVERY_RATE 0x10
#define DMPF_MAX_RECOVERY_RATE 0x20
#define DMPF_MAX_WRITE_BEHIND  0x40
#define DMPF_STRIPE_CACHE      0x80
#define DMPF_REGION_SIZE       0X100
struct raid_set {
	struct dm_target *ti;

	uint64_t print_flags;

	struct mddev md;
	struct raid_type *raid_type;
	struct dm_target_callbacks callbacks;

	struct raid_dev dev[0];
};

/* Supported raid types and properties. */
static struct raid_type {
	const char *name;		/* RAID algorithm. */
	const char *descr;		/* Descriptor text for logging. */
	const unsigned parity_devs;	/* # of parity devices. */
	const unsigned minimal_devs;	/* minimal # of devices in set. */
	const unsigned level;		/* RAID level. */
	const unsigned algorithm;	/* RAID algorithm. */
} raid_types[] = {
	{"raid1",    "RAID1 (mirroring)",               0, 2, 1, 0 /* NONE */},
	{"raid4",    "RAID4 (dedicated parity disk)",	1, 2, 5, ALGORITHM_PARITY_0},
	{"raid5_la", "RAID5 (left asymmetric)",		1, 2, 5, ALGORITHM_LEFT_ASYMMETRIC},
	{"raid5_ra", "RAID5 (right asymmetric)",	1, 2, 5, ALGORITHM_RIGHT_ASYMMETRIC},
	{"raid5_ls", "RAID5 (left symmetric)",		1, 2, 5, ALGORITHM_LEFT_SYMMETRIC},
	{"raid5_rs", "RAID5 (right symmetric)",		1, 2, 5, ALGORITHM_RIGHT_SYMMETRIC},
	{"raid6_zr", "RAID6 (zero restart)",		2, 4, 6, ALGORITHM_ROTATING_ZERO_RESTART},
	{"raid6_nr", "RAID6 (N restart)",		2, 4, 6, ALGORITHM_ROTATING_N_RESTART},
	{"raid6_nc", "RAID6 (N continue)",		2, 4, 6, ALGORITHM_ROTATING_N_CONTINUE}
};

static struct raid_type *get_raid_type(char *name)
{
	int i;

	for (i = 0; i < ARRAY_SIZE(raid_types); i++)
		if (!strcmp(raid_types[i].name, name))
			return &raid_types[i];

	return NULL;
}

static struct raid_set *context_alloc(struct dm_target *ti, struct raid_type *raid_type, unsigned raid_devs)
{
	unsigned i;
	struct raid_set *rs;
	sector_t sectors_per_dev;

	if (raid_devs <= raid_type->parity_devs) {
		ti->error