[deliverable/linux.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;

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

	uint32_t chunk_size;

	/* 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;
	char dummy;

	if (sscanf(argv[1], "%llu%c", &start, &dummy) != 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> [<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;
	int r;
	unsigned int i;

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

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

	if (kstrtouint(argv[1], 10, &chunk_size) || !chunk_size) {
		ti->error = "Invalid chunk_size";
		return -EINVAL;
	}

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

	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);

	r = dm_set_target_max_io_len(ti, chunk_size);
	if (r)
		return r;

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

	sc->chunk_size = chunk_size;

	/*
	 * 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 chunk = dm_target_offset(sc->ti, sector);
	sector_t chunk_offset = sector_div(chunk, sc->chunk_size);

	if (sc->stripes_shift < 0)
		*stripe = sector_div(chunk, sc->stripes);
	else {
		*stripe = chunk & (sc->stripes - 1);
		chunk >>= sc->stripes_shift;
	}

	*result = (chunk * sc->chunk_size) + chunk_offset;
}

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;

	/* round down */
	sector = *result;
	*result -= sector_div(sector, sc->chunk_size);

	if (target_stripe < stripe)
		*result += sc->chunk_size;		/* 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_size);
		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_size << SECTOR_SHIFT;

	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, 5, 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	28	int stripes_shift;
1da177e4 LT	29
	30	/* The size of this target / num. stripes */
	31	sector_t stripe_width;
	32
eb850de6	33	uint32_t chunk_size;
1da177e4	34
a25eb944 BW	35	/* Needed for handling events */
	36	struct dm_target *ti;
	37
	38	/* Work struct used for triggering events*/
f521f074	39	struct work_struct trigger_event;
a25eb944	40
1da177e4 LT	41	struct stripe stripe[0];
	42	};
	43
a25eb944 BW	44	/*
	45	* An event is triggered whenever a drive
	46	* drops out of a stripe volume.
	47	*/
	48	static void trigger_event(struct work_struct *work)
	49	{
f521f074 TH	50	struct stripe_c *sc = container_of(work, struct stripe_c,
f521f074 TH	51	trigger_event);
a25eb944	52	dm_table_event(sc->ti->table);
a25eb944 BW	53	}
a25eb944 BW	54
1da177e4 LT	55	static inline struct stripe_c *alloc_context(unsigned int stripes)
	56	{
	57	size_t len;
	58
d63a5ce3 MP	59	if (dm_array_too_big(sizeof(struct stripe_c), sizeof(struct stripe),
d63a5ce3 MP	60	stripes))
1da177e4 LT	61	return NULL;
	62
	63	len = sizeof(struct stripe_c) + (sizeof(struct stripe) * stripes);
	64
	65	return kmalloc(len, GFP_KERNEL);
	66	}
	67
	68	/*
	69	* Parse a single <dev> <sector> pair
	70	*/
	71	static int get_stripe(struct dm_target ti, struct stripe_c sc,
	72	unsigned int stripe, char **argv)
	73	{
4ee218cd	74	unsigned long long start;
31998ef1	75	char dummy;
1da177e4	76
31998ef1	77	if (sscanf(argv[1], "%llu%c", &start, &dummy) != 1)
1da177e4 LT	78	return -EINVAL;
1da177e4 LT	79
8215d6ec	80	if (dm_get_device(ti, argv[0], dm_table_get_mode(ti->table),
1da177e4 LT	81	&sc->stripe[stripe].dev))
	82	return -ENXIO;
	83
	84	sc->stripe[stripe].physical_start = start;
a25eb944	85
1da177e4 LT	86	return 0;
	87	}
	88
	89	/*
	90	* Construct a striped mapping.
eb850de6	91	* <number of stripes> <chunk size> [<dev_path> <offset>]+
1da177e4 LT	92	*/
	93	static int stripe_ctr(struct dm_target ti, unsigned int argc, char *argv)
	94	{
	95	struct stripe_c *sc;
	96	sector_t width;
	97	uint32_t stripes;
	98	uint32_t chunk_size;
1da177e4 LT	99	int r;
	100	unsigned int i;
	101
	102	if (argc < 2) {
72d94861	103	ti->error = "Not enough arguments";
1da177e4 LT	104	return -EINVAL;
	105	}
	106
1a66a08a	107	if (kstrtouint(argv[0], 10, &stripes) \|\| !stripes) {
72d94861	108	ti->error = "Invalid stripe count";
1da177e4 LT	109	return -EINVAL;
	110	}
	111
8f069b41	112	if (kstrtouint(argv[1], 10, &chunk_size) \|\| !chunk_size) {
eb850de6	113	ti->error = "Invalid chunk_size";
1da177e4 LT	114	return -EINVAL;
	115	}
	116
eb850de6 MS	117	width = ti->len;
eb850de6 MS	118	if (sector_div(width, chunk_size)) {
72d94861	119	ti->error = "Target length not divisible by "
8ba32fde KC	120	"chunk size";
	121	return -EINVAL;
	122	}
	123
1da177e4	124	if (sector_div(width, stripes)) {
72d94861	125	ti->error = "Target length not divisible by "
1da177e4 LT	126	"number of stripes";
	127	return -EINVAL;
	128	}
	129
	130	/*
	131	* Do we have enough arguments for that many stripes ?
	132	*/
	133	if (argc != (2 + 2 * stripes)) {
72d94861	134	ti->error = "Not enough destinations "
1da177e4 LT	135	"specified";
	136	return -EINVAL;
	137	}
	138
	139	sc = alloc_context(stripes);
	140	if (!sc) {
72d94861	141	ti->error = "Memory allocation for striped context "
1da177e4 LT	142	"failed";
	143	return -ENOMEM;
	144	}
	145
f521f074	146	INIT_WORK(&sc->trigger_event, trigger_event);
a25eb944 BW	147
	148	/* Set pointer to dm target; used in trigger_event */
	149	sc->ti = ti;
1da177e4 LT	150	sc->stripes = stripes;
1da177e4 LT	151	sc->stripe_width = width;
c96053b7 MP	152
	153	if (stripes & (stripes - 1))
	154	sc->stripes_shift = -1;
1df05483 MP	155	else
1df05483 MP	156	sc->stripes_shift = __ffs(stripes);
c96053b7	157
542f9038 MS	158	r = dm_set_target_max_io_len(ti, chunk_size);
	159	if (r)
	160	return r;
	161
374bf7e7	162	ti->num_flush_requests = stripes;
7b76ec11	163	ti->num_discard_requests = stripes;
1da177e4	164
eb850de6	165	sc->chunk_size = chunk_size;
1da177e4 LT	166
	167	/*
	168	* Get the stripe destinations.
	169	*/
	170	for (i = 0; i < stripes; i++) {
	171	argv += 2;
	172
	173	r = get_stripe(ti, sc, i, argv);
	174	if (r < 0) {
72d94861	175	ti->error = "Couldn't parse stripe destination";
1da177e4 LT	176	while (i--)
	177	dm_put_device(ti, sc->stripe[i].dev);
	178	kfree(sc);
	179	return r;
	180	}
a25eb944	181	atomic_set(&(sc->stripe[i].error_count), 0);
1da177e4 LT	182	}
	183
	184	ti->private = sc;
a25eb944	185
1da177e4 LT	186	return 0;
	187	}
	188
	189	static void stripe_dtr(struct dm_target *ti)
	190	{
	191	unsigned int i;
	192	struct stripe_c sc = (struct stripe_c ) ti->private;
	193
	194	for (i = 0; i < sc->stripes; i++)
	195	dm_put_device(ti, sc->stripe[i].dev);
	196
f521f074	197	flush_work_sync(&sc->trigger_event);
1da177e4 LT	198	kfree(sc);
	199	}
	200
65988525 MP	201	static void stripe_map_sector(struct stripe_c *sc, sector_t sector,
	202	uint32_t stripe, sector_t result)
	203	{
eb850de6 MS	204	sector_t chunk = dm_target_offset(sc->ti, sector);
eb850de6 MS	205	sector_t chunk_offset = sector_div(chunk, sc->chunk_size);
65988525	206
c96053b7 MP	207	if (sc->stripes_shift < 0)
	208	*stripe = sector_div(chunk, sc->stripes);
	209	else {
1df05483	210	*stripe = chunk & (sc->stripes - 1);
c96053b7 MP	211	chunk >>= sc->stripes_shift;
	212	}
	213
eb850de6	214	result = (chunk sc->chunk_size) + chunk_offset;
65988525 MP	215	}
65988525 MP	216
7b76ec11 MP	217	static void stripe_map_range_sector(struct stripe_c *sc, sector_t sector,
	218	uint32_t target_stripe, sector_t *result)
	219	{
	220	uint32_t stripe;
	221
	222	stripe_map_sector(sc, sector, &stripe, result);
	223	if (stripe == target_stripe)
	224	return;
eb850de6 MS	225
	226	/* round down */
	227	sector = *result;
	228	*result -= sector_div(sector, sc->chunk_size);
	229
7b76ec11	230	if (target_stripe < stripe)
eb850de6	231	result += sc->chunk_size; / next chunk */
7b76ec11 MP	232	}
	233
	234	static int stripe_map_discard(struct stripe_c sc, struct bio bio,
	235	uint32_t target_stripe)
	236	{
	237	sector_t begin, end;
	238
	239	stripe_map_range_sector(sc, bio->bi_sector, target_stripe, &begin);
	240	stripe_map_range_sector(sc, bio->bi_sector + bio_sectors(bio),
	241	target_stripe, &end);
	242	if (begin < end) {
	243	bio->bi_bdev = sc->stripe[target_stripe].dev->bdev;
	244	bio->bi_sector = begin + sc->stripe[target_stripe].physical_start;
	245	bio->bi_size = to_bytes(end - begin);
	246	return DM_MAPIO_REMAPPED;
	247	} else {
	248	/* The range doesn't map to the target stripe */
	249	bio_endio(bio, 0);
	250	return DM_MAPIO_SUBMITTED;
	251	}
	252	}
	253
1da177e4 LT	254	static int stripe_map(struct dm_target ti, struct bio bio,
	255	union map_info *map_context)
	256	{
65988525	257	struct stripe_c *sc = ti->private;
374bf7e7	258	uint32_t stripe;
57cba5d3	259	unsigned target_request_nr;
1da177e4	260
d87f4c14	261	if (bio->bi_rw & REQ_FLUSH) {
57cba5d3 MS	262	target_request_nr = map_context->target_request_nr;
	263	BUG_ON(target_request_nr >= sc->stripes);
	264	bio->bi_bdev = sc->stripe[target_request_nr].dev->bdev;
374bf7e7 MP	265	return DM_MAPIO_REMAPPED;
374bf7e7 MP	266	}
7b76ec11 MP	267	if (unlikely(bio->bi_rw & REQ_DISCARD)) {
	268	target_request_nr = map_context->target_request_nr;
	269	BUG_ON(target_request_nr >= sc->stripes);
	270	return stripe_map_discard(sc, bio, target_request_nr);
	271	}
374bf7e7	272
65988525	273	stripe_map_sector(sc, bio->bi_sector, &stripe, &bio->bi_sector);
1da177e4	274
65988525	275	bio->bi_sector += sc->stripe[stripe].physical_start;
1da177e4	276	bio->bi_bdev = sc->stripe[stripe].dev->bdev;
65988525	277
d2a7ad29	278	return DM_MAPIO_REMAPPED;
1da177e4 LT	279	}
1da177e4 LT	280
4f7f5c67 BW	281	/*
	282	* Stripe status:
	283	*
	284	* INFO
	285	* #stripes [stripe_name <stripe_name>] [group word count]
	286	* [error count 'A\|D' <error count 'A\|D'>]
	287	*
	288	* TABLE
	289	* #stripes [stripe chunk size]
	290	* [stripe_name physical_start <stripe_name physical_start>]
	291	*
	292	*/
	293
1da177e4 LT	294	static int stripe_status(struct dm_target *ti,
	295	status_type_t type, char *result, unsigned int maxlen)
	296	{
	297	struct stripe_c sc = (struct stripe_c ) ti->private;
4f7f5c67	298	char buffer[sc->stripes + 1];
1da177e4 LT	299	unsigned int sz = 0;
	300	unsigned int i;
	301
	302	switch (type) {
	303	case STATUSTYPE_INFO:
4f7f5c67 BW	304	DMEMIT("%d ", sc->stripes);
	305	for (i = 0; i < sc->stripes; i++) {
	306	DMEMIT("%s ", sc->stripe[i].dev->name);
	307	buffer[i] = atomic_read(&(sc->stripe[i].error_count)) ?
	308	'D' : 'A';
	309	}
	310	buffer[i] = '\0';
	311	DMEMIT("1 %s", buffer);
1da177e4 LT	312	break;
	313
	314	case STATUSTYPE_TABLE:
4ee218cd	315	DMEMIT("%d %llu", sc->stripes,
eb850de6	316	(unsigned long long)sc->chunk_size);
1da177e4	317	for (i = 0; i < sc->stripes; i++)
4ee218cd AM	318	DMEMIT(" %s %llu", sc->stripe[i].dev->name,
4ee218cd AM	319	(unsigned long long)sc->stripe[i].physical_start);
1da177e4 LT	320	break;
	321	}
	322	return 0;
	323	}
	324
a25eb944 BW	325	static int stripe_end_io(struct dm_target ti, struct bio bio,
	326	int error, union map_info *map_context)
	327	{
	328	unsigned i;
	329	char major_minor[16];
	330	struct stripe_c *sc = ti->private;
	331
	332	if (!error)
	333	return 0; /* I/O complete */
	334
7b6d91da	335	if ((error == -EWOULDBLOCK) && (bio->bi_rw & REQ_RAHEAD))
a25eb944 BW	336	return error;
	337
	338	if (error == -EOPNOTSUPP)
	339	return error;
	340
	341	memset(major_minor, 0, sizeof(major_minor));
	342	sprintf(major_minor, "%d:%d",
f331c029 TH	343	MAJOR(disk_devt(bio->bi_bdev->bd_disk)),
f331c029 TH	344	MINOR(disk_devt(bio->bi_bdev->bd_disk)));
a25eb944 BW	345
	346	/*
	347	* Test to see which stripe drive triggered the event
	348	* and increment error count for all stripes on that device.
	349	* If the error count for a given device exceeds the threshold
	350	* value we will no longer trigger any further events.
	351	*/
	352	for (i = 0; i < sc->stripes; i++)
	353	if (!strcmp(sc->stripe[i].dev->name, major_minor)) {
	354	atomic_inc(&(sc->stripe[i].error_count));
	355	if (atomic_read(&(sc->stripe[i].error_count)) <
	356	DM_IO_ERROR_THRESHOLD)
f521f074	357	schedule_work(&sc->trigger_event);
a25eb944 BW	358	}
	359
	360	return error;
	361	}
	362
af4874e0 MS	363	static int stripe_iterate_devices(struct dm_target *ti,
	364	iterate_devices_callout_fn fn, void *data)
	365	{
	366	struct stripe_c *sc = ti->private;
	367	int ret = 0;
	368	unsigned i = 0;
	369
5dea271b	370	do {
af4874e0	371	ret = fn(ti, sc->stripe[i].dev,
5dea271b MS	372	sc->stripe[i].physical_start,
	373	sc->stripe_width, data);
	374	} while (!ret && ++i < sc->stripes);
af4874e0 MS	375
	376	return ret;
	377	}
	378
40bea431 MS	379	static void stripe_io_hints(struct dm_target *ti,
	380	struct queue_limits *limits)
	381	{
	382	struct stripe_c *sc = ti->private;
eb850de6	383	unsigned chunk_size = sc->chunk_size << SECTOR_SHIFT;
40bea431 MS	384
40bea431 MS	385	blk_limits_io_min(limits, chunk_size);
3c5820c7	386	blk_limits_io_opt(limits, chunk_size * sc->stripes);
40bea431 MS	387	}
40bea431 MS	388
29915202 MM	389	static int stripe_merge(struct dm_target ti, struct bvec_merge_data bvm,
	390	struct bio_vec *biovec, int max_size)
	391	{
	392	struct stripe_c *sc = ti->private;
	393	sector_t bvm_sector = bvm->bi_sector;
	394	uint32_t stripe;
	395	struct request_queue *q;
	396
	397	stripe_map_sector(sc, bvm_sector, &stripe, &bvm_sector);
	398
	399	q = bdev_get_queue(sc->stripe[stripe].dev->bdev);
	400	if (!q->merge_bvec_fn)
	401	return max_size;
	402
	403	bvm->bi_bdev = sc->stripe[stripe].dev->bdev;
	404	bvm->bi_sector = sc->stripe[stripe].physical_start + bvm_sector;
	405
	406	return min(max_size, q->merge_bvec_fn(q, bvm, biovec));
	407	}
	408
1da177e4 LT	409	static struct target_type stripe_target = {
1da177e4 LT	410	.name = "striped",
eb850de6	411	.version = {1, 5, 0},
1da177e4 LT	412	.module = THIS_MODULE,
	413	.ctr = stripe_ctr,
	414	.dtr = stripe_dtr,
	415	.map = stripe_map,
a25eb944	416	.end_io = stripe_end_io,
1da177e4	417	.status = stripe_status,
af4874e0	418	.iterate_devices = stripe_iterate_devices,
40bea431	419	.io_hints = stripe_io_hints,
29915202	420	.merge = stripe_merge,
1da177e4 LT	421	};
	422
	423	int __init dm_stripe_init(void)
	424	{
	425	int r;
	426
	427	r = dm_register_target(&stripe_target);
6edebdee	428	if (r < 0) {
72d94861	429	DMWARN("target registration failed");
6edebdee HM	430	return r;
6edebdee HM	431	}
1da177e4 LT	432
	433	return r;
	434	}
	435
	436	void dm_stripe_exit(void)
	437	{
10d3bd09	438	dm_unregister_target(&stripe_target);
1da177e4	439	}