[net-next-2.6.git] / drivers / md / dm-stripe.c

/*
 * Copyright (C) 2001-2003 Sistina Software (UK) Limited.
 *
 * This file is released under the GPL.
 */

#include <linux/device-mapper.h>

#include <linux/module.h>
#include <linux/init.h>
#include <linux/blkdev.h>
#include <linux/bio.h>
#include <linux/slab.h>
#include <linux/log2.h>

#define DM_MSG_PREFIX "striped"
#define DM_IO_ERROR_THRESHOLD 15

struct stripe {
	struct dm_dev *dev;
	sector_t physical_start;

	atomic_t error_count;
};

struct stripe_c {
	uint32_t stripes;
	int stripes_shift;
	sector_t stripes_mask;

	/* The size of this target / num. stripes */
	sector_t stripe_width;

	/* stripe chunk size */
	uint32_t chunk_shift;
	sector_t chunk_mask;

	/* Needed for handling events */
	struct dm_target *ti;

	/* Work struct used for triggering events*/
	struct work_struct kstriped_ws;

	struct stripe stripe[0];
};

static struct workqueue_struct *kstriped;

/*
 * An event is triggered whenever a drive
 * drops out of a stripe volume.
 */
static void trigger_event(struct work_struct *work)
{
	struct stripe_c *sc = container_of(work, struct stripe_c, kstriped_ws);

	dm_table_event(sc->ti->table);

}

static inline struct stripe_c *alloc_context(unsigned int stripes)
{
	size_t len;

	if (dm_array_too_big(sizeof(struct stripe_c), sizeof(struct stripe),
			     stripes))
		return NULL;

	len = sizeof(struct stripe_c) + (sizeof(struct stripe) * stripes);

	return kmalloc(len, GFP_KERNEL);
}

/*
 * Parse a single <dev> <sector> pair
 */
static int get_stripe(struct dm_target *ti, struct stripe_c *sc,
		      unsigned int stripe, char **argv)
{
	unsigned long long start;

	if (sscanf(argv[1], "%llu", &start) != 1)
		return -EINVAL;

	if (dm_get_device(ti, argv[0], dm_table_get_mode(ti->table),
			  &sc->stripe[stripe].dev))
		return -ENXIO;

	sc->stripe[stripe].physical_start = start;

	return 0;
}

/*
 * Construct a striped mapping.
 * <number of stripes> <chunk size (2^^n)> [<dev_path> <offset>]+
 */
static int stripe_ctr(struct dm_target *ti, unsigned int argc, char **argv)
{
	struct stripe_c *sc;
	sector_t width;
	uint32_t stripes;
	uint32_t chunk_size;
	char *end;
	int r;
	unsigned int i;

	if (argc < 2) {
		ti->error = "Not enough arguments";
		return -EINVAL;
	}

	stripes = simple_strtoul(argv[0], &end, 10);
	if (!stripes || *end) {
		ti->error = "Invalid stripe count";
		return -EINVAL;
	}

	chunk_size = simple_strtoul(argv[1], &end, 10);
	if (*end) {
		ti->error = "Invalid chunk_size";
		return -EINVAL;
	}

	/*
	 * chunk_size is a power of two
	 */
	if (!is_power_of_2(chunk_size) ||
	    (chunk_size < (PAGE_SIZE >> SECTOR_SHIFT))) {
		ti->error = "Invalid chunk size";
		return -EINVAL;
	}

	if (ti->len & (chunk_size - 1)) {
		ti->error = "Target length not divisible by "
		    "chunk size";
		return -EINVAL;
	}

	width = ti->len;
	if (sector_div(width, stripes)) {
		ti->error = "Target length not divisible by "
		    "number of stripes";
		return -EINVAL;
	}

	/*
	 * Do we have enough arguments for that many stripes ?
	 */
	if (argc != (2 + 2 * stripes)) {
		ti->error = "Not enough destinations "
			"specified";
		return -EINVAL;
	}

	sc = alloc_context(stripes);
	if (!sc) {
		ti->error = "Memory allocation for striped context "
		    "failed";
		return -ENOMEM;
	}

	INIT_WORK(&sc->kstriped_ws, trigger_event);

	/* Set pointer to dm target; used in trigger_event */
	sc->ti = ti;
	sc->stripes = stripes;
	sc->stripe_width = width;

	if (stripes & (stripes - 1))
		sc->stripes_shift = -1;
	else {
		sc->stripes_shift = ffs(stripes) - 1;
		sc->stripes_mask = ((sector_t) stripes) - 1;
	}

	ti->split_io = chunk_size;
	ti->num_flush_requests = stripes;
	ti->num_discard_requests = stripes;

	sc->chunk_shift = ffs(chunk_size) - 1;
	sc->chunk_mask = ((sector_t) chunk_size) - 1;

	/*
	 * Get the stripe destinations.
	 */
	for (i = 0; i < stripes; i++) {
		argv += 2;

		r = get_stripe(ti, sc, i, argv);
		if (r < 0) {
			ti->error = "Couldn't parse stripe destination";
			while (i--)
				dm_put_device(ti, sc->stripe[i].dev);
			kfree(sc);
			return r;
		}
		atomic_set(&(sc->stripe[i].error_count), 0);
	}

	ti->private = sc;

	return 0;
}

static void stripe_dtr(struct dm_target *ti)
{
	unsigned int i;
	struct stripe_c *sc = (struct stripe_c *) ti->private;

	for (i = 0; i < sc->stripes; i++)
		dm_put_device(ti, sc->stripe[i].dev);

	flush_workqueue(kstriped);
	kfree(sc);
}

static void stripe_map_sector(struct stripe_c *sc, sector_t sector,
			      uint32_t *stripe, sector_t *result)
{
	sector_t offset = dm_target_offset(sc->ti, sector);
	sector_t chunk = offset >> sc->chunk_shift;

	if (sc->stripes_shift < 0)
		*stripe = sector_div(chunk, sc->stripes);
	else {
		*stripe = chunk & sc->stripes_mask;
		chunk >>= sc->stripes_shift;
	}

	*result = (chunk << sc->chunk_shift) | (offset & sc->chunk_mask);
}

static void stripe_map_range_sector(struct stripe_c *sc, sector_t sector,
				    uint32_t target_stripe, sector_t *result)
{
	uint32_t stripe;

	stripe_map_sector(sc, sector, &stripe, result);
	if (stripe == target_stripe)
		return;
	*result &= ~sc->chunk_mask;			/* round down */
	if (target_stripe < stripe)
		*result += sc->chunk_mask + 1;		/* next chunk */
}

static int stripe_map_discard(struct stripe_c *sc, struct bio *bio,
			      uint32_t target_stripe)
{
	sector_t begin, end;

	stripe_map_range_sector(sc, bio->bi_sector, target_stripe, &begin);
	stripe_map_range_sector(sc, bio->bi_sector + bio_sectors(bio),
				target_stripe, &end);
	if (begin < end) {
		bio->bi_bdev = sc->stripe[target_stripe].dev->bdev;
		bio->bi_sector = begin + sc->stripe[target_stripe].physical_start;
		bio->bi_size = to_bytes(end - begin);
		return DM_MAPIO_REMAPPED;
	} else {
		/* The range doesn't map to the target stripe */
		bio_endio(bio, 0);
		return DM_MAPIO_SUBMITTED;
	}
}

static int stripe_map(struct dm_target *ti, struct bio *bio,
		      union map_info *map_context)
{
	struct stripe_c *sc = ti->private;
	uint32_t stripe;
	unsigned target_request_nr;

	if (bio->bi_rw & REQ_FLUSH) {
		target_request_nr = map_context->target_request_nr;
		BUG_ON(target_request_nr >= sc->stripes);
		bio->bi_bdev = sc->stripe[target_request_nr].dev->bdev;
		return DM_MAPIO_REMAPPED;
	}
	if (unlikely(bio->bi_rw & REQ_DISCARD)) {
		target_request_nr = map_context->target_request_nr;
		BUG_ON(target_request_nr >= sc->stripes);
		return stripe_map_discard(sc, bio, target_request_nr);
	}

	stripe_map_sector(sc, bio->bi_sector, &stripe, &bio->bi_sector);

	bio->bi_sector += sc->stripe[stripe].physical_start;
	bio->bi_bdev = sc->stripe[stripe].dev->bdev;

	return DM_MAPIO_REMAPPED;
}

/*
 * Stripe status:
 *
 * INFO
 * #stripes [stripe_name <stripe_name>] [group word count]
 * [error count 'A|D' <error count 'A|D'>]
 *
 * TABLE
 * #stripes [stripe chunk size]
 * [stripe_name physical_start <stripe_name physical_start>]
 *
 */

static int stripe_status(struct dm_target *ti,
			 status_type_t type, char *result, unsigned int maxlen)
{
	struct stripe_c *sc = (struct stripe_c *) ti->private;
	char buffer[sc->stripes + 1];
	unsigned int sz = 0;
	unsigned int i;

	switch (type) {
	case STATUSTYPE_INFO:
		DMEMIT("%d ", sc->stripes);
		for (i = 0; i < sc->stripes; i++)  {
			DMEMIT("%s ", sc->stripe[i].dev->name);
			buffer[i] = atomic_read(&(sc->stripe[i].error_count)) ?
				'D' : 'A';
		}
		buffer[i] = '\0';
		DMEMIT("1 %s", buffer);
		break;

	case STATUSTYPE_TABLE:
		DMEMIT("%d %llu", sc->stripes,
			(unsigned long long)sc->chunk_mask + 1);
		for (i = 0; i < sc->stripes; i++)
			DMEMIT(" %s %llu", sc->stripe[i].dev->name,
			    (unsigned long long)sc->stripe[i].physical_start);
		break;
	}
	return 0;
}

static int stripe_end_io(struct dm_target *ti, struct bio *bio,
			 int error, union map_info *map_context)
{
	unsigned i;
	char major_minor[16];
	struct stripe_c *sc = ti->private;

	if (!error)
		return 0; /* I/O complete */

	if ((error == -EWOULDBLOCK) && (bio->bi_rw & REQ_RAHEAD))
		return error;

	if (error == -EOPNOTSUPP)
		return error;

	memset(major_minor, 0, sizeof(major_minor));
	sprintf(major_minor, "%d:%d",
		MAJOR(disk_devt(bio->bi_bdev->bd_disk)),
		MINOR(disk_devt(bio->bi_bdev->bd_disk)));

	/*
	 * Test to see which stripe drive triggered the event
	 * and increment error count for all stripes on that device.
	 * If the error count for a given device exceeds the threshold
	 * value we will no longer trigger any further events.
	 */
	for (i = 0; i < sc->stripes; i++)
		if (!strcmp(sc->stripe[i].dev->name, major_minor)) {
			atomic_inc(&(sc->stripe[i].error_count));
			if (atomic_read(&(sc->stripe[i].error_count)) <
			    DM_IO_ERROR_THRESHOLD)
				queue_work(kstriped, &sc->kstriped_ws);
		}

	return error;
}

static int stripe_iterate_devices(struct dm_target *ti,
				  iterate_devices_callout_fn fn, void *data)
{
	struct stripe_c *sc = ti->private;
	int ret = 0;
	unsigned i = 0;

	do {
		ret = fn(ti, sc->stripe[i].dev,
			 sc->stripe[i].physical_start,
			 sc->stripe_width, data);
	} while (!ret && ++i < sc->stripes);

	return ret;
}

static void stripe_io_hints(struct dm_target *ti,
			    struct queue_limits *limits)
{
	struct stripe_c *sc = ti->private;
	unsigned chunk_size = (sc->chunk_mask + 1) << 9;

	blk_limits_io_min(limits, chunk_size);
	blk_limits_io_opt(limits, chunk_size * sc->stripes);
}

static struct target_type stripe_target = {
	.name   = "striped",
	.version = {1, 3, 0},
	.module = THIS_MODULE,
	.ctr    = stripe_ctr,
	.dtr    = stripe_dtr,
	.map    = stripe_map,
	.end_io = stripe_end_io,
	.status = stripe_status,
	.iterate_devices = stripe_iterate_devices,
	.io_hints = stripe_io_hints,
};

int __init dm_stripe_init(void)
{
	int r;

	r = dm_register_target(&stripe_target);
	if (r < 0) {
		DMWARN("target registration failed");
		return r;
	}

	kstriped = create_singlethread_workqueue("kstriped");
	if (!kstriped) {
		DMERR("failed to create workqueue kstriped");
		dm_unregister_target(&stripe_target);
		return -ENOMEM;
	}

	return r;
}

void dm_stripe_exit(void)
{
	dm_unregister_target(&stripe_target);
	destroy_workqueue(kstriped);

	return;
}
Commit	Line	Data
1da177e4 LT	1	/*
	2	* Copyright (C) 2001-2003 Sistina Software (UK) Limited.
	3	*
	4	* This file is released under the GPL.
	5	*/
	6
586e80e6	7	#include <linux/device-mapper.h>
1da177e4 LT	8
	9	#include <linux/module.h>
	10	#include <linux/init.h>
	11	#include <linux/blkdev.h>
	12	#include <linux/bio.h>
	13	#include <linux/slab.h>
6f3c3f0a	14	#include <linux/log2.h>
1da177e4	15
72d94861	16	#define DM_MSG_PREFIX "striped"
a25eb944	17	#define DM_IO_ERROR_THRESHOLD 15
72d94861	18
1da177e4 LT	19	struct stripe {
	20	struct dm_dev *dev;
	21	sector_t physical_start;
a25eb944 BW	22
a25eb944 BW	23	atomic_t error_count;
1da177e4 LT	24	};
	25
	26	struct stripe_c {
	27	uint32_t stripes;
c96053b7 MP	28	int stripes_shift;
c96053b7 MP	29	sector_t stripes_mask;
1da177e4 LT	30
	31	/* The size of this target / num. stripes */
	32	sector_t stripe_width;
	33
	34	/* stripe chunk size */
	35	uint32_t chunk_shift;
	36	sector_t chunk_mask;
	37
a25eb944 BW	38	/* Needed for handling events */
	39	struct dm_target *ti;
	40
	41	/* Work struct used for triggering events*/
	42	struct work_struct kstriped_ws;
	43
1da177e4 LT	44	struct stripe stripe[0];
	45	};
	46
a25eb944 BW	47	static struct workqueue_struct *kstriped;
	48
	49	/*
	50	* An event is triggered whenever a drive
	51	* drops out of a stripe volume.
	52	*/
	53	static void trigger_event(struct work_struct *work)
	54	{
	55	struct stripe_c *sc = container_of(work, struct stripe_c, kstriped_ws);
	56
	57	dm_table_event(sc->ti->table);
	58
	59	}
	60
1da177e4 LT	61	static inline struct stripe_c *alloc_context(unsigned int stripes)
	62	{
	63	size_t len;
	64
d63a5ce3 MP	65	if (dm_array_too_big(sizeof(struct stripe_c), sizeof(struct stripe),
d63a5ce3 MP	66	stripes))
1da177e4 LT	67	return NULL;
	68
	69	len = sizeof(struct stripe_c) + (sizeof(struct stripe) * stripes);
	70
	71	return kmalloc(len, GFP_KERNEL);
	72	}
	73
	74	/*
	75	* Parse a single <dev> <sector> pair
	76	*/
	77	static int get_stripe(struct dm_target ti, struct stripe_c sc,
	78	unsigned int stripe, char **argv)
	79	{
4ee218cd	80	unsigned long long start;
1da177e4	81
4ee218cd	82	if (sscanf(argv[1], "%llu", &start) != 1)
1da177e4 LT	83	return -EINVAL;
1da177e4 LT	84
8215d6ec	85	if (dm_get_device(ti, argv[0], dm_table_get_mode(ti->table),
1da177e4 LT	86	&sc->stripe[stripe].dev))
	87	return -ENXIO;
	88
	89	sc->stripe[stripe].physical_start = start;
a25eb944	90
1da177e4 LT	91	return 0;
	92	}
	93
	94	/*
	95	* Construct a striped mapping.
	96	* <number of stripes> <chunk size (2^^n)> [<dev_path> <offset>]+
	97	*/
	98	static int stripe_ctr(struct dm_target ti, unsigned int argc, char *argv)
	99	{
	100	struct stripe_c *sc;
	101	sector_t width;
	102	uint32_t stripes;
	103	uint32_t chunk_size;
	104	char *end;
	105	int r;
	106	unsigned int i;
	107
	108	if (argc < 2) {
72d94861	109	ti->error = "Not enough arguments";
1da177e4 LT	110	return -EINVAL;
	111	}
	112
	113	stripes = simple_strtoul(argv[0], &end, 10);
781248c1	114	if (!stripes \|\| *end) {
72d94861	115	ti->error = "Invalid stripe count";
1da177e4 LT	116	return -EINVAL;
	117	}
	118
	119	chunk_size = simple_strtoul(argv[1], &end, 10);
	120	if (*end) {
72d94861	121	ti->error = "Invalid chunk_size";
1da177e4 LT	122	return -EINVAL;
	123	}
	124
	125	/*
	126	* chunk_size is a power of two
	127	*/
6f3c3f0a	128	if (!is_power_of_2(chunk_size) \|\|
1da177e4	129	(chunk_size < (PAGE_SIZE >> SECTOR_SHIFT))) {
72d94861	130	ti->error = "Invalid chunk size";
1da177e4 LT	131	return -EINVAL;
	132	}
	133
a22c96c7	134	if (ti->len & (chunk_size - 1)) {
72d94861	135	ti->error = "Target length not divisible by "
8ba32fde KC	136	"chunk size";
	137	return -EINVAL;
	138	}
	139
1da177e4 LT	140	width = ti->len;
1da177e4 LT	141	if (sector_div(width, stripes)) {
72d94861	142	ti->error = "Target length not divisible by "
1da177e4 LT	143	"number of stripes";
	144	return -EINVAL;
	145	}
	146
	147	/*
	148	* Do we have enough arguments for that many stripes ?
	149	*/
	150	if (argc != (2 + 2 * stripes)) {
72d94861	151	ti->error = "Not enough destinations "
1da177e4 LT	152	"specified";
	153	return -EINVAL;
	154	}
	155
	156	sc = alloc_context(stripes);
	157	if (!sc) {
72d94861	158	ti->error = "Memory allocation for striped context "
1da177e4 LT	159	"failed";
	160	return -ENOMEM;
	161	}
	162
a25eb944 BW	163	INIT_WORK(&sc->kstriped_ws, trigger_event);
	164
	165	/* Set pointer to dm target; used in trigger_event */
	166	sc->ti = ti;
1da177e4 LT	167	sc->stripes = stripes;
1da177e4 LT	168	sc->stripe_width = width;
c96053b7 MP	169
	170	if (stripes & (stripes - 1))
	171	sc->stripes_shift = -1;
	172	else {
	173	sc->stripes_shift = ffs(stripes) - 1;
	174	sc->stripes_mask = ((sector_t) stripes) - 1;
	175	}
	176
1da177e4	177	ti->split_io = chunk_size;
374bf7e7	178	ti->num_flush_requests = stripes;
7b76ec11	179	ti->num_discard_requests = stripes;
1da177e4	180
c96053b7	181	sc->chunk_shift = ffs(chunk_size) - 1;
1da177e4	182	sc->chunk_mask = ((sector_t) chunk_size) - 1;
1da177e4 LT	183
	184	/*
	185	* Get the stripe destinations.
	186	*/
	187	for (i = 0; i < stripes; i++) {
	188	argv += 2;
	189
	190	r = get_stripe(ti, sc, i, argv);
	191	if (r < 0) {
72d94861	192	ti->error = "Couldn't parse stripe destination";
1da177e4 LT	193	while (i--)
	194	dm_put_device(ti, sc->stripe[i].dev);
	195	kfree(sc);
	196	return r;
	197	}
a25eb944	198	atomic_set(&(sc->stripe[i].error_count), 0);
1da177e4 LT	199	}
	200
	201	ti->private = sc;
a25eb944	202
1da177e4 LT	203	return 0;
	204	}
	205
	206	static void stripe_dtr(struct dm_target *ti)
	207	{
	208	unsigned int i;
	209	struct stripe_c sc = (struct stripe_c ) ti->private;
	210
	211	for (i = 0; i < sc->stripes; i++)
	212	dm_put_device(ti, sc->stripe[i].dev);
	213
a25eb944	214	flush_workqueue(kstriped);
1da177e4 LT	215	kfree(sc);
	216	}
	217
65988525 MP	218	static void stripe_map_sector(struct stripe_c *sc, sector_t sector,
	219	uint32_t stripe, sector_t result)
	220	{
	221	sector_t offset = dm_target_offset(sc->ti, sector);
	222	sector_t chunk = offset >> sc->chunk_shift;
	223
c96053b7 MP	224	if (sc->stripes_shift < 0)
	225	*stripe = sector_div(chunk, sc->stripes);
	226	else {
	227	*stripe = chunk & sc->stripes_mask;
	228	chunk >>= sc->stripes_shift;
	229	}
	230
65988525 MP	231	*result = (chunk << sc->chunk_shift) \| (offset & sc->chunk_mask);
	232	}
	233
7b76ec11 MP	234	static void stripe_map_range_sector(struct stripe_c *sc, sector_t sector,
	235	uint32_t target_stripe, sector_t *result)
	236	{
	237	uint32_t stripe;
	238
	239	stripe_map_sector(sc, sector, &stripe, result);
	240	if (stripe == target_stripe)
	241	return;
	242	result &= ~sc->chunk_mask; / round down */
	243	if (target_stripe < stripe)
	244	result += sc->chunk_mask + 1; / next chunk */
	245	}
	246
	247	static int stripe_map_discard(struct stripe_c sc, struct bio bio,
	248	uint32_t target_stripe)
	249	{
	250	sector_t begin, end;
	251
	252	stripe_map_range_sector(sc, bio->bi_sector, target_stripe, &begin);
	253	stripe_map_range_sector(sc, bio->bi_sector + bio_sectors(bio),
	254	target_stripe, &end);
	255	if (begin < end) {
	256	bio->bi_bdev = sc->stripe[target_stripe].dev->bdev;
	257	bio->bi_sector = begin + sc->stripe[target_stripe].physical_start;
	258	bio->bi_size = to_bytes(end - begin);
	259	return DM_MAPIO_REMAPPED;
	260	} else {
	261	/* The range doesn't map to the target stripe */
	262	bio_endio(bio, 0);
	263	return DM_MAPIO_SUBMITTED;
	264	}
	265	}
	266
1da177e4 LT	267	static int stripe_map(struct dm_target ti, struct bio bio,
	268	union map_info *map_context)
	269	{
65988525	270	struct stripe_c *sc = ti->private;
374bf7e7	271	uint32_t stripe;
57cba5d3	272	unsigned target_request_nr;
1da177e4	273
d87f4c14	274	if (bio->bi_rw & REQ_FLUSH) {
57cba5d3 MS	275	target_request_nr = map_context->target_request_nr;
	276	BUG_ON(target_request_nr >= sc->stripes);
	277	bio->bi_bdev = sc->stripe[target_request_nr].dev->bdev;
374bf7e7 MP	278	return DM_MAPIO_REMAPPED;
374bf7e7 MP	279	}
7b76ec11 MP	280	if (unlikely(bio->bi_rw & REQ_DISCARD)) {
	281	target_request_nr = map_context->target_request_nr;
	282	BUG_ON(target_request_nr >= sc->stripes);
	283	return stripe_map_discard(sc, bio, target_request_nr);
	284	}
374bf7e7	285
65988525	286	stripe_map_sector(sc, bio->bi_sector, &stripe, &bio->bi_sector);
1da177e4	287
65988525	288	bio->bi_sector += sc->stripe[stripe].physical_start;
1da177e4	289	bio->bi_bdev = sc->stripe[stripe].dev->bdev;
65988525	290
d2a7ad29	291	return DM_MAPIO_REMAPPED;
1da177e4 LT	292	}
1da177e4 LT	293
4f7f5c67 BW	294	/*
	295	* Stripe status:
	296	*
	297	* INFO
	298	* #stripes [stripe_name <stripe_name>] [group word count]
	299	* [error count 'A\|D' <error count 'A\|D'>]
	300	*
	301	* TABLE
	302	* #stripes [stripe chunk size]
	303	* [stripe_name physical_start <stripe_name physical_start>]
	304	*
	305	*/
	306
1da177e4 LT	307	static int stripe_status(struct dm_target *ti,
	308	status_type_t type, char *result, unsigned int maxlen)
	309	{
	310	struct stripe_c sc = (struct stripe_c ) ti->private;
4f7f5c67	311	char buffer[sc->stripes + 1];
1da177e4 LT	312	unsigned int sz = 0;
	313	unsigned int i;
	314
	315	switch (type) {
	316	case STATUSTYPE_INFO:
4f7f5c67 BW	317	DMEMIT("%d ", sc->stripes);
	318	for (i = 0; i < sc->stripes; i++) {
	319	DMEMIT("%s ", sc->stripe[i].dev->name);
	320	buffer[i] = atomic_read(&(sc->stripe[i].error_count)) ?
	321	'D' : 'A';
	322	}
	323	buffer[i] = '\0';
	324	DMEMIT("1 %s", buffer);
1da177e4 LT	325	break;
	326
	327	case STATUSTYPE_TABLE:
4ee218cd AM	328	DMEMIT("%d %llu", sc->stripes,
4ee218cd AM	329	(unsigned long long)sc->chunk_mask + 1);
1da177e4	330	for (i = 0; i < sc->stripes; i++)
4ee218cd AM	331	DMEMIT(" %s %llu", sc->stripe[i].dev->name,
4ee218cd AM	332	(unsigned long long)sc->stripe[i].physical_start);
1da177e4 LT	333	break;
	334	}
	335	return 0;
	336	}
	337
a25eb944 BW	338	static int stripe_end_io(struct dm_target ti, struct bio bio,
	339	int error, union map_info *map_context)
	340	{
	341	unsigned i;
	342	char major_minor[16];
	343	struct stripe_c *sc = ti->private;
	344
	345	if (!error)
	346	return 0; /* I/O complete */
	347
7b6d91da	348	if ((error == -EWOULDBLOCK) && (bio->bi_rw & REQ_RAHEAD))
a25eb944 BW	349	return error;
	350
	351	if (error == -EOPNOTSUPP)
	352	return error;
	353
	354	memset(major_minor, 0, sizeof(major_minor));
	355	sprintf(major_minor, "%d:%d",
f331c029 TH	356	MAJOR(disk_devt(bio->bi_bdev->bd_disk)),
f331c029 TH	357	MINOR(disk_devt(bio->bi_bdev->bd_disk)));
a25eb944 BW	358
	359	/*
	360	* Test to see which stripe drive triggered the event
	361	* and increment error count for all stripes on that device.
	362	* If the error count for a given device exceeds the threshold
	363	* value we will no longer trigger any further events.
	364	*/
	365	for (i = 0; i < sc->stripes; i++)
	366	if (!strcmp(sc->stripe[i].dev->name, major_minor)) {
	367	atomic_inc(&(sc->stripe[i].error_count));
	368	if (atomic_read(&(sc->stripe[i].error_count)) <
	369	DM_IO_ERROR_THRESHOLD)
	370	queue_work(kstriped, &sc->kstriped_ws);
	371	}
	372
	373	return error;
	374	}
	375
af4874e0 MS	376	static int stripe_iterate_devices(struct dm_target *ti,
	377	iterate_devices_callout_fn fn, void *data)
	378	{
	379	struct stripe_c *sc = ti->private;
	380	int ret = 0;
	381	unsigned i = 0;
	382
5dea271b	383	do {
af4874e0	384	ret = fn(ti, sc->stripe[i].dev,
5dea271b MS	385	sc->stripe[i].physical_start,
	386	sc->stripe_width, data);
	387	} while (!ret && ++i < sc->stripes);
af4874e0 MS	388
	389	return ret;
	390	}
	391
40bea431 MS	392	static void stripe_io_hints(struct dm_target *ti,
	393	struct queue_limits *limits)
	394	{
	395	struct stripe_c *sc = ti->private;
	396	unsigned chunk_size = (sc->chunk_mask + 1) << 9;
	397
	398	blk_limits_io_min(limits, chunk_size);
3c5820c7	399	blk_limits_io_opt(limits, chunk_size * sc->stripes);
40bea431 MS	400	}
40bea431 MS	401
1da177e4 LT	402	static struct target_type stripe_target = {
1da177e4 LT	403	.name = "striped",
40bea431	404	.version = {1, 3, 0},
1da177e4 LT	405	.module = THIS_MODULE,
	406	.ctr = stripe_ctr,
	407	.dtr = stripe_dtr,
	408	.map = stripe_map,
a25eb944	409	.end_io = stripe_end_io,
1da177e4	410	.status = stripe_status,
af4874e0	411	.iterate_devices = stripe_iterate_devices,
40bea431	412	.io_hints = stripe_io_hints,
1da177e4 LT	413	};
	414
	415	int __init dm_stripe_init(void)
	416	{
	417	int r;
	418
	419	r = dm_register_target(&stripe_target);
6edebdee	420	if (r < 0) {
72d94861	421	DMWARN("target registration failed");
6edebdee HM	422	return r;
6edebdee HM	423	}
1da177e4	424
a25eb944 BW	425	kstriped = create_singlethread_workqueue("kstriped");
	426	if (!kstriped) {
	427	DMERR("failed to create workqueue kstriped");
	428	dm_unregister_target(&stripe_target);
	429	return -ENOMEM;
	430	}
	431
1da177e4 LT	432	return r;
	433	}
	434
	435	void dm_stripe_exit(void)
	436	{
10d3bd09	437	dm_unregister_target(&stripe_target);
a25eb944 BW	438	destroy_workqueue(kstriped);
a25eb944 BW	439
1da177e4 LT	440	return;
1da177e4 LT	441	}