[mirror_ubuntu-zesty-kernel.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 trigger_event;

	struct stripe stripe[0];
};

/*
 * 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,
					   trigger_event);
	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->trigger_event, 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_work_sync(&sc->trigger_event);
	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)
				schedule_work(&sc->trigger_event);
		}

	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 int stripe_merge(struct dm_target *ti, struct bvec_merge_data *bvm,
			struct bio_vec *biovec, int max_size)
{
	struct stripe_c *sc = ti->private;
	sector_t bvm_sector = bvm->bi_sector;
	uint32_t stripe;
	struct request_queue *q;

	stripe_map_sector(sc, bvm_sector, &stripe, &bvm_sector);

	q = bdev_get_queue(sc->stripe[stripe].dev->bdev);
	if (!q->merge_bvec_fn)
		return max_size;

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

	return min(max_size, q->merge_bvec_fn(q, bvm, biovec));
}

static struct target_type stripe_target = {
	.name   = "striped",
	.version = {1, 4, 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,
	.merge  = stripe_merge,
};

int __init dm_stripe_init(void)
{
	int r;

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

	return r;
}

void dm_stripe_exit(void)
{
	dm_unregister_target(&stripe_target);
}
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*/
f521f074	42	struct work_struct trigger_event;
a25eb944	43
1da177e4 LT	44	struct stripe stripe[0];
	45	};
	46
a25eb944 BW	47	/*
	48	* An event is triggered whenever a drive
	49	* drops out of a stripe volume.
	50	*/
	51	static void trigger_event(struct work_struct *work)
	52	{
f521f074 TH	53	struct stripe_c *sc = container_of(work, struct stripe_c,
f521f074 TH	54	trigger_event);
a25eb944	55	dm_table_event(sc->ti->table);
a25eb944 BW	56	}
a25eb944 BW	57
1da177e4 LT	58	static inline struct stripe_c *alloc_context(unsigned int stripes)
	59	{
	60	size_t len;
	61
d63a5ce3 MP	62	if (dm_array_too_big(sizeof(struct stripe_c), sizeof(struct stripe),
d63a5ce3 MP	63	stripes))
1da177e4 LT	64	return NULL;
	65
	66	len = sizeof(struct stripe_c) + (sizeof(struct stripe) * stripes);
	67
	68	return kmalloc(len, GFP_KERNEL);
	69	}
	70
	71	/*
	72	* Parse a single <dev> <sector> pair
	73	*/
	74	static int get_stripe(struct dm_target ti, struct stripe_c sc,
	75	unsigned int stripe, char **argv)
	76	{
4ee218cd	77	unsigned long long start;
1da177e4	78
4ee218cd	79	if (sscanf(argv[1], "%llu", &start) != 1)
1da177e4 LT	80	return -EINVAL;
1da177e4 LT	81
8215d6ec	82	if (dm_get_device(ti, argv[0], dm_table_get_mode(ti->table),
1da177e4 LT	83	&sc->stripe[stripe].dev))
	84	return -ENXIO;
	85
	86	sc->stripe[stripe].physical_start = start;
a25eb944	87
1da177e4 LT	88	return 0;
	89	}
	90
	91	/*
	92	* Construct a striped mapping.
	93	* <number of stripes> <chunk size (2^^n)> [<dev_path> <offset>]+
	94	*/
	95	static int stripe_ctr(struct dm_target ti, unsigned int argc, char *argv)
	96	{
	97	struct stripe_c *sc;
	98	sector_t width;
	99	uint32_t stripes;
	100	uint32_t chunk_size;
	101	char *end;
	102	int r;
	103	unsigned int i;
	104
	105	if (argc < 2) {
72d94861	106	ti->error = "Not enough arguments";
1da177e4 LT	107	return -EINVAL;
	108	}
	109
	110	stripes = simple_strtoul(argv[0], &end, 10);
781248c1	111	if (!stripes \|\| *end) {
72d94861	112	ti->error = "Invalid stripe count";
1da177e4 LT	113	return -EINVAL;
	114	}
	115
	116	chunk_size = simple_strtoul(argv[1], &end, 10);
	117	if (*end) {
72d94861	118	ti->error = "Invalid chunk_size";
1da177e4 LT	119	return -EINVAL;
	120	}
	121
	122	/*
	123	* chunk_size is a power of two
	124	*/
6f3c3f0a	125	if (!is_power_of_2(chunk_size) \|\|
1da177e4	126	(chunk_size < (PAGE_SIZE >> SECTOR_SHIFT))) {
72d94861	127	ti->error = "Invalid chunk size";
1da177e4 LT	128	return -EINVAL;
	129	}
	130
a22c96c7	131	if (ti->len & (chunk_size - 1)) {
72d94861	132	ti->error = "Target length not divisible by "
8ba32fde KC	133	"chunk size";
	134	return -EINVAL;
	135	}
	136
1da177e4 LT	137	width = ti->len;
1da177e4 LT	138	if (sector_div(width, stripes)) {
72d94861	139	ti->error = "Target length not divisible by "
1da177e4 LT	140	"number of stripes";
	141	return -EINVAL;
	142	}
	143
	144	/*
	145	* Do we have enough arguments for that many stripes ?
	146	*/
	147	if (argc != (2 + 2 * stripes)) {
72d94861	148	ti->error = "Not enough destinations "
1da177e4 LT	149	"specified";
	150	return -EINVAL;
	151	}
	152
	153	sc = alloc_context(stripes);
	154	if (!sc) {
72d94861	155	ti->error = "Memory allocation for striped context "
1da177e4 LT	156	"failed";
	157	return -ENOMEM;
	158	}
	159
f521f074	160	INIT_WORK(&sc->trigger_event, trigger_event);
a25eb944 BW	161
	162	/* Set pointer to dm target; used in trigger_event */
	163	sc->ti = ti;
1da177e4 LT	164	sc->stripes = stripes;
1da177e4 LT	165	sc->stripe_width = width;
c96053b7 MP	166
	167	if (stripes & (stripes - 1))
	168	sc->stripes_shift = -1;
	169	else {
	170	sc->stripes_shift = ffs(stripes) - 1;
	171	sc->stripes_mask = ((sector_t) stripes) - 1;
	172	}
	173
1da177e4	174	ti->split_io = chunk_size;
374bf7e7	175	ti->num_flush_requests = stripes;
7b76ec11	176	ti->num_discard_requests = stripes;
1da177e4	177
c96053b7	178	sc->chunk_shift = ffs(chunk_size) - 1;
1da177e4	179	sc->chunk_mask = ((sector_t) chunk_size) - 1;
1da177e4 LT	180
	181	/*
	182	* Get the stripe destinations.
	183	*/
	184	for (i = 0; i < stripes; i++) {
	185	argv += 2;
	186
	187	r = get_stripe(ti, sc, i, argv);
	188	if (r < 0) {
72d94861	189	ti->error = "Couldn't parse stripe destination";
1da177e4 LT	190	while (i--)
	191	dm_put_device(ti, sc->stripe[i].dev);
	192	kfree(sc);
	193	return r;
	194	}
a25eb944	195	atomic_set(&(sc->stripe[i].error_count), 0);
1da177e4 LT	196	}
	197
	198	ti->private = sc;
a25eb944	199
1da177e4 LT	200	return 0;
	201	}
	202
	203	static void stripe_dtr(struct dm_target *ti)
	204	{
	205	unsigned int i;
	206	struct stripe_c sc = (struct stripe_c ) ti->private;
	207
	208	for (i = 0; i < sc->stripes; i++)
	209	dm_put_device(ti, sc->stripe[i].dev);
	210
f521f074	211	flush_work_sync(&sc->trigger_event);
1da177e4 LT	212	kfree(sc);
	213	}
	214
65988525 MP	215	static void stripe_map_sector(struct stripe_c *sc, sector_t sector,
	216	uint32_t stripe, sector_t result)
	217	{
	218	sector_t offset = dm_target_offset(sc->ti, sector);
	219	sector_t chunk = offset >> sc->chunk_shift;
	220
c96053b7 MP	221	if (sc->stripes_shift < 0)
	222	*stripe = sector_div(chunk, sc->stripes);
	223	else {
	224	*stripe = chunk & sc->stripes_mask;
	225	chunk >>= sc->stripes_shift;
	226	}
	227
65988525 MP	228	*result = (chunk << sc->chunk_shift) \| (offset & sc->chunk_mask);
	229	}
	230
7b76ec11 MP	231	static void stripe_map_range_sector(struct stripe_c *sc, sector_t sector,
	232	uint32_t target_stripe, sector_t *result)
	233	{
	234	uint32_t stripe;
	235
	236	stripe_map_sector(sc, sector, &stripe, result);
	237	if (stripe == target_stripe)
	238	return;
	239	result &= ~sc->chunk_mask; / round down */
	240	if (target_stripe < stripe)
	241	result += sc->chunk_mask + 1; / next chunk */
	242	}
	243
	244	static int stripe_map_discard(struct stripe_c sc, struct bio bio,
	245	uint32_t target_stripe)
	246	{
	247	sector_t begin, end;
	248
	249	stripe_map_range_sector(sc, bio->bi_sector, target_stripe, &begin);
	250	stripe_map_range_sector(sc, bio->bi_sector + bio_sectors(bio),
	251	target_stripe, &end);
	252	if (begin < end) {
	253	bio->bi_bdev = sc->stripe[target_stripe].dev->bdev;
	254	bio->bi_sector = begin + sc->stripe[target_stripe].physical_start;
	255	bio->bi_size = to_bytes(end - begin);
	256	return DM_MAPIO_REMAPPED;
	257	} else {
	258	/* The range doesn't map to the target stripe */
	259	bio_endio(bio, 0);
	260	return DM_MAPIO_SUBMITTED;
	261	}
	262	}
	263
1da177e4 LT	264	static int stripe_map(struct dm_target ti, struct bio bio,
	265	union map_info *map_context)
	266	{
65988525	267	struct stripe_c *sc = ti->private;
374bf7e7	268	uint32_t stripe;
57cba5d3	269	unsigned target_request_nr;
1da177e4	270
d87f4c14	271	if (bio->bi_rw & REQ_FLUSH) {
57cba5d3 MS	272	target_request_nr = map_context->target_request_nr;
	273	BUG_ON(target_request_nr >= sc->stripes);
	274	bio->bi_bdev = sc->stripe[target_request_nr].dev->bdev;
374bf7e7 MP	275	return DM_MAPIO_REMAPPED;
374bf7e7 MP	276	}
7b76ec11 MP	277	if (unlikely(bio->bi_rw & REQ_DISCARD)) {
	278	target_request_nr = map_context->target_request_nr;
	279	BUG_ON(target_request_nr >= sc->stripes);
	280	return stripe_map_discard(sc, bio, target_request_nr);
	281	}
374bf7e7	282
65988525	283	stripe_map_sector(sc, bio->bi_sector, &stripe, &bio->bi_sector);
1da177e4	284
65988525	285	bio->bi_sector += sc->stripe[stripe].physical_start;
1da177e4	286	bio->bi_bdev = sc->stripe[stripe].dev->bdev;
65988525	287
d2a7ad29	288	return DM_MAPIO_REMAPPED;
1da177e4 LT	289	}
1da177e4 LT	290
4f7f5c67 BW	291	/*
	292	* Stripe status:
	293	*
	294	* INFO
	295	* #stripes [stripe_name <stripe_name>] [group word count]
	296	* [error count 'A\|D' <error count 'A\|D'>]
	297	*
	298	* TABLE
	299	* #stripes [stripe chunk size]
	300	* [stripe_name physical_start <stripe_name physical_start>]
	301	*
	302	*/
	303
1da177e4 LT	304	static int stripe_status(struct dm_target *ti,
	305	status_type_t type, char *result, unsigned int maxlen)
	306	{
	307	struct stripe_c sc = (struct stripe_c ) ti->private;
4f7f5c67	308	char buffer[sc->stripes + 1];
1da177e4 LT	309	unsigned int sz = 0;
	310	unsigned int i;
	311
	312	switch (type) {
	313	case STATUSTYPE_INFO:
4f7f5c67 BW	314	DMEMIT("%d ", sc->stripes);
	315	for (i = 0; i < sc->stripes; i++) {
	316	DMEMIT("%s ", sc->stripe[i].dev->name);
	317	buffer[i] = atomic_read(&(sc->stripe[i].error_count)) ?
	318	'D' : 'A';
	319	}
	320	buffer[i] = '\0';
	321	DMEMIT("1 %s", buffer);
1da177e4 LT	322	break;
	323
	324	case STATUSTYPE_TABLE:
4ee218cd AM	325	DMEMIT("%d %llu", sc->stripes,
4ee218cd AM	326	(unsigned long long)sc->chunk_mask + 1);
1da177e4	327	for (i = 0; i < sc->stripes; i++)
4ee218cd AM	328	DMEMIT(" %s %llu", sc->stripe[i].dev->name,
4ee218cd AM	329	(unsigned long long)sc->stripe[i].physical_start);
1da177e4 LT	330	break;
	331	}
	332	return 0;
	333	}
	334
a25eb944 BW	335	static int stripe_end_io(struct dm_target ti, struct bio bio,
	336	int error, union map_info *map_context)
	337	{
	338	unsigned i;
	339	char major_minor[16];
	340	struct stripe_c *sc = ti->private;
	341
	342	if (!error)
	343	return 0; /* I/O complete */
	344
7b6d91da	345	if ((error == -EWOULDBLOCK) && (bio->bi_rw & REQ_RAHEAD))
a25eb944 BW	346	return error;
	347
	348	if (error == -EOPNOTSUPP)
	349	return error;
	350
	351	memset(major_minor, 0, sizeof(major_minor));
	352	sprintf(major_minor, "%d:%d",
f331c029 TH	353	MAJOR(disk_devt(bio->bi_bdev->bd_disk)),
f331c029 TH	354	MINOR(disk_devt(bio->bi_bdev->bd_disk)));
a25eb944 BW	355
	356	/*
	357	* Test to see which stripe drive triggered the event
	358	* and increment error count for all stripes on that device.
	359	* If the error count for a given device exceeds the threshold
	360	* value we will no longer trigger any further events.
	361	*/
	362	for (i = 0; i < sc->stripes; i++)
	363	if (!strcmp(sc->stripe[i].dev->name, major_minor)) {
	364	atomic_inc(&(sc->stripe[i].error_count));
	365	if (atomic_read(&(sc->stripe[i].error_count)) <
	366	DM_IO_ERROR_THRESHOLD)
f521f074	367	schedule_work(&sc->trigger_event);
a25eb944 BW	368	}
	369
	370	return error;
	371	}
	372
af4874e0 MS	373	static int stripe_iterate_devices(struct dm_target *ti,
	374	iterate_devices_callout_fn fn, void *data)
	375	{
	376	struct stripe_c *sc = ti->private;
	377	int ret = 0;
	378	unsigned i = 0;
	379
5dea271b	380	do {
af4874e0	381	ret = fn(ti, sc->stripe[i].dev,
5dea271b MS	382	sc->stripe[i].physical_start,
	383	sc->stripe_width, data);
	384	} while (!ret && ++i < sc->stripes);
af4874e0 MS	385
	386	return ret;
	387	}
	388
40bea431 MS	389	static void stripe_io_hints(struct dm_target *ti,
	390	struct queue_limits *limits)
	391	{
	392	struct stripe_c *sc = ti->private;
	393	unsigned chunk_size = (sc->chunk_mask + 1) << 9;
	394
	395	blk_limits_io_min(limits, chunk_size);
3c5820c7	396	blk_limits_io_opt(limits, chunk_size * sc->stripes);
40bea431 MS	397	}
40bea431 MS	398
29915202 MM	399	static int stripe_merge(struct dm_target ti, struct bvec_merge_data bvm,
	400	struct bio_vec *biovec, int max_size)
	401	{
	402	struct stripe_c *sc = ti->private;
	403	sector_t bvm_sector = bvm->bi_sector;
	404	uint32_t stripe;
	405	struct request_queue *q;
	406
	407	stripe_map_sector(sc, bvm_sector, &stripe, &bvm_sector);
	408
	409	q = bdev_get_queue(sc->stripe[stripe].dev->bdev);
	410	if (!q->merge_bvec_fn)
	411	return max_size;
	412
	413	bvm->bi_bdev = sc->stripe[stripe].dev->bdev;
	414	bvm->bi_sector = sc->stripe[stripe].physical_start + bvm_sector;
	415
	416	return min(max_size, q->merge_bvec_fn(q, bvm, biovec));
	417	}
	418
1da177e4 LT	419	static struct target_type stripe_target = {
1da177e4 LT	420	.name = "striped",
29915202	421	.version = {1, 4, 0},
1da177e4 LT	422	.module = THIS_MODULE,
	423	.ctr = stripe_ctr,
	424	.dtr = stripe_dtr,
	425	.map = stripe_map,
a25eb944	426	.end_io = stripe_end_io,
1da177e4	427	.status = stripe_status,
af4874e0	428	.iterate_devices = stripe_iterate_devices,
40bea431	429	.io_hints = stripe_io_hints,
29915202	430	.merge = stripe_merge,
1da177e4 LT	431	};
	432
	433	int __init dm_stripe_init(void)
	434	{
	435	int r;
	436
	437	r = dm_register_target(&stripe_target);
6edebdee	438	if (r < 0) {
72d94861	439	DMWARN("target registration failed");
6edebdee HM	440	return r;
6edebdee HM	441	}
1da177e4 LT	442
	443	return r;
	444	}
	445
	446	void dm_stripe_exit(void)
	447	{
10d3bd09	448	dm_unregister_target(&stripe_target);
1da177e4	449	}