[linux-2.6-block.git] / drivers / md / dm-stripe.c

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

#include "dm.h"
#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;
	int chunk_size_shift;

	/* 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, tmp_len;
	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, stripes)) {
		ti->error = "Target length not divisible by "
		    "number of stripes";
		return -EINVAL;
	}

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

	ti->num_flush_bios = stripes;
	ti->num_discard_bios = stripes;
	ti->num_write_same_bios = stripes;

	sc->chunk_size = chunk_size;
	if (chunk_size & (chunk_size - 1))
		sc->chunk_size_shift = -1;
	else
		sc->chunk_size_shift = __ffs(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(&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;

	if (sc->chunk_size_shift < 0)
		chunk_offset = sector_div(chunk, sc->chunk_size);
	else {
		chunk_offset = chunk & (sc->chunk_size - 1);
		chunk >>= sc->chunk_size_shift;
	}

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

	if (sc->chunk_size_shift < 0)
		chunk *= sc->chunk_size;
	else
		chunk <<= sc->chunk_size_shift;

	*result = chunk + 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;
	if (sc->chunk_size_shift < 0)
		*result -= sector_div(sector, sc->chunk_size);
	else
		*result = sector & ~(sector_t)(sc->chunk_size - 1);

	if (target_stripe < stripe)
		*result += sc->chunk_size;		/* next chunk */
}

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

	stripe_map_range_sector(sc, bio->bi_iter.bi_sector,
				target_stripe, &begin);
	stripe_map_range_sector(sc, bio_end_sector(bio),
				target_stripe, &end);
	if (begin < end) {
		bio->bi_bdev = sc->stripe[target_stripe].dev->bdev;
		bio->bi_iter.bi_sector = begin +
			sc->stripe[target_stripe].physical_start;
		bio->bi_iter.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)
{
	struct stripe_c *sc = ti->private;
	uint32_t stripe;
	unsigned target_bio_nr;

	if (bio->bi_rw & REQ_FLUSH) {
		target_bio_nr = dm_bio_get_target_bio_nr(bio);
		BUG_ON(target_bio_nr >= sc->stripes);
		bio->bi_bdev = sc->stripe[target_bio_nr].dev->bdev;
		return DM_MAPIO_REMAPPED;
	}
	if (unlikely(bio->bi_rw & REQ_DISCARD) ||
	    unlikely(bio->bi_rw & REQ_WRITE_SAME)) {
		target_bio_nr = dm_bio_get_target_bio_nr(bio);
		BUG_ON(target_bio_nr >= sc->stripes);
		return stripe_map_range(sc, bio, target_bio_nr);
	}

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

	bio->bi_iter.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 void stripe_status(struct dm_target *ti, status_type_t type,
			  unsigned status_flags, char *result, unsigned 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;
	}
}

static int stripe_end_io(struct dm_target *ti, struct bio *bio, int error)
{
	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, 1},
	.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
7fff5e8f	7	#include "dm.h"
586e80e6	8	#include <linux/device-mapper.h>
1da177e4 LT	9
	10	#include <linux/module.h>
	11	#include <linux/init.h>
	12	#include <linux/blkdev.h>
	13	#include <linux/bio.h>
	14	#include <linux/slab.h>
6f3c3f0a	15	#include <linux/log2.h>
1da177e4	16
72d94861	17	#define DM_MSG_PREFIX "striped"
a25eb944	18	#define DM_IO_ERROR_THRESHOLD 15
72d94861	19
1da177e4 LT	20	struct stripe {
	21	struct dm_dev *dev;
	22	sector_t physical_start;
a25eb944 BW	23
a25eb944 BW	24	atomic_t error_count;
1da177e4 LT	25	};
	26
	27	struct stripe_c {
	28	uint32_t stripes;
c96053b7	29	int stripes_shift;
1da177e4 LT	30
	31	/* The size of this target / num. stripes */
	32	sector_t stripe_width;
	33
eb850de6	34	uint32_t chunk_size;
33d07c0d	35	int chunk_size_shift;
1da177e4	36
a25eb944 BW	37	/* Needed for handling events */
	38	struct dm_target *ti;
	39
	40	/* Work struct used for triggering events*/
f521f074	41	struct work_struct trigger_event;
a25eb944	42
1da177e4 LT	43	struct stripe stripe[0];
	44	};
	45
a25eb944 BW	46	/*
	47	* An event is triggered whenever a drive
	48	* drops out of a stripe volume.
	49	*/
	50	static void trigger_event(struct work_struct *work)
	51	{
f521f074 TH	52	struct stripe_c *sc = container_of(work, struct stripe_c,
f521f074 TH	53	trigger_event);
a25eb944	54	dm_table_event(sc->ti->table);
a25eb944 BW	55	}
a25eb944 BW	56
1da177e4 LT	57	static inline struct stripe_c *alloc_context(unsigned int stripes)
	58	{
	59	size_t len;
	60
d63a5ce3 MP	61	if (dm_array_too_big(sizeof(struct stripe_c), sizeof(struct stripe),
d63a5ce3 MP	62	stripes))
1da177e4 LT	63	return NULL;
	64
	65	len = sizeof(struct stripe_c) + (sizeof(struct stripe) * stripes);
	66
	67	return kmalloc(len, GFP_KERNEL);
	68	}
	69
	70	/*
	71	* Parse a single <dev> <sector> pair
	72	*/
	73	static int get_stripe(struct dm_target ti, struct stripe_c sc,
	74	unsigned int stripe, char **argv)
	75	{
4ee218cd	76	unsigned long long start;
31998ef1	77	char dummy;
1da177e4	78
31998ef1	79	if (sscanf(argv[1], "%llu%c", &start, &dummy) != 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.
eb850de6	93	* <number of stripes> <chunk size> [<dev_path> <offset>]+
1da177e4 LT	94	*/
	95	static int stripe_ctr(struct dm_target ti, unsigned int argc, char *argv)
	96	{
	97	struct stripe_c *sc;
d793e684	98	sector_t width, tmp_len;
1da177e4 LT	99	uint32_t stripes;
1da177e4 LT	100	uint32_t chunk_size;
1da177e4 LT	101	int r;
	102	unsigned int i;
	103
	104	if (argc < 2) {
72d94861	105	ti->error = "Not enough arguments";
1da177e4 LT	106	return -EINVAL;
	107	}
	108
1a66a08a	109	if (kstrtouint(argv[0], 10, &stripes) \|\| !stripes) {
72d94861	110	ti->error = "Invalid stripe count";
1da177e4 LT	111	return -EINVAL;
	112	}
	113
8f069b41	114	if (kstrtouint(argv[1], 10, &chunk_size) \|\| !chunk_size) {
eb850de6	115	ti->error = "Invalid chunk_size";
1da177e4 LT	116	return -EINVAL;
	117	}
	118
eb850de6	119	width = ti->len;
d793e684	120	if (sector_div(width, stripes)) {
72d94861	121	ti->error = "Target length not divisible by "
d793e684	122	"number of stripes";
8ba32fde KC	123	return -EINVAL;
	124	}
	125
d793e684 MS	126	tmp_len = width;
d793e684 MS	127	if (sector_div(tmp_len, chunk_size)) {
72d94861	128	ti->error = "Target length not divisible by "
d793e684	129	"chunk size";
1da177e4 LT	130	return -EINVAL;
	131	}
	132
	133	/*
	134	* Do we have enough arguments for that many stripes ?
	135	*/
	136	if (argc != (2 + 2 * stripes)) {
72d94861	137	ti->error = "Not enough destinations "
1da177e4 LT	138	"specified";
	139	return -EINVAL;
	140	}
	141
	142	sc = alloc_context(stripes);
	143	if (!sc) {
72d94861	144	ti->error = "Memory allocation for striped context "
1da177e4 LT	145	"failed";
	146	return -ENOMEM;
	147	}
	148
f521f074	149	INIT_WORK(&sc->trigger_event, trigger_event);
a25eb944 BW	150
	151	/* Set pointer to dm target; used in trigger_event */
	152	sc->ti = ti;
1da177e4 LT	153	sc->stripes = stripes;
1da177e4 LT	154	sc->stripe_width = width;
c96053b7 MP	155
	156	if (stripes & (stripes - 1))
	157	sc->stripes_shift = -1;
1df05483 MP	158	else
1df05483 MP	159	sc->stripes_shift = __ffs(stripes);
c96053b7	160
542f9038	161	r = dm_set_target_max_io_len(ti, chunk_size);
a3f2af25 PK	162	if (r) {
a3f2af25 PK	163	kfree(sc);
542f9038	164	return r;
a3f2af25	165	}
542f9038	166
55a62eef AK	167	ti->num_flush_bios = stripes;
	168	ti->num_discard_bios = stripes;
	169	ti->num_write_same_bios = stripes;
1da177e4	170
eb850de6	171	sc->chunk_size = chunk_size;
33d07c0d MP	172	if (chunk_size & (chunk_size - 1))
	173	sc->chunk_size_shift = -1;
	174	else
	175	sc->chunk_size_shift = __ffs(chunk_size);
1da177e4 LT	176
	177	/*
	178	* Get the stripe destinations.
	179	*/
	180	for (i = 0; i < stripes; i++) {
	181	argv += 2;
	182
	183	r = get_stripe(ti, sc, i, argv);
	184	if (r < 0) {
72d94861	185	ti->error = "Couldn't parse stripe destination";
1da177e4 LT	186	while (i--)
	187	dm_put_device(ti, sc->stripe[i].dev);
	188	kfree(sc);
	189	return r;
	190	}
a25eb944	191	atomic_set(&(sc->stripe[i].error_count), 0);
1da177e4 LT	192	}
	193
	194	ti->private = sc;
a25eb944	195
1da177e4 LT	196	return 0;
	197	}
	198
	199	static void stripe_dtr(struct dm_target *ti)
	200	{
	201	unsigned int i;
	202	struct stripe_c sc = (struct stripe_c ) ti->private;
	203
	204	for (i = 0; i < sc->stripes; i++)
	205	dm_put_device(ti, sc->stripe[i].dev);
	206
43829731	207	flush_work(&sc->trigger_event);
1da177e4 LT	208	kfree(sc);
	209	}
	210
65988525 MP	211	static void stripe_map_sector(struct stripe_c *sc, sector_t sector,
	212	uint32_t stripe, sector_t result)
	213	{
eb850de6	214	sector_t chunk = dm_target_offset(sc->ti, sector);
33d07c0d MP	215	sector_t chunk_offset;
	216
	217	if (sc->chunk_size_shift < 0)
	218	chunk_offset = sector_div(chunk, sc->chunk_size);
	219	else {
	220	chunk_offset = chunk & (sc->chunk_size - 1);
	221	chunk >>= sc->chunk_size_shift;
	222	}
65988525	223
c96053b7 MP	224	if (sc->stripes_shift < 0)
	225	*stripe = sector_div(chunk, sc->stripes);
	226	else {
1df05483	227	*stripe = chunk & (sc->stripes - 1);
c96053b7 MP	228	chunk >>= sc->stripes_shift;
	229	}
	230
33d07c0d MP	231	if (sc->chunk_size_shift < 0)
	232	chunk *= sc->chunk_size;
	233	else
	234	chunk <<= sc->chunk_size_shift;
	235
	236	*result = chunk + chunk_offset;
65988525 MP	237	}
65988525 MP	238
7b76ec11 MP	239	static void stripe_map_range_sector(struct stripe_c *sc, sector_t sector,
	240	uint32_t target_stripe, sector_t *result)
	241	{
	242	uint32_t stripe;
	243
	244	stripe_map_sector(sc, sector, &stripe, result);
	245	if (stripe == target_stripe)
	246	return;
eb850de6 MS	247
	248	/* round down */
	249	sector = *result;
33d07c0d MP	250	if (sc->chunk_size_shift < 0)
	251	*result -= sector_div(sector, sc->chunk_size);
	252	else
	253	*result = sector & ~(sector_t)(sc->chunk_size - 1);
eb850de6	254
7b76ec11	255	if (target_stripe < stripe)
eb850de6	256	result += sc->chunk_size; / next chunk */
7b76ec11 MP	257	}
7b76ec11 MP	258
45e621d4 MS	259	static int stripe_map_range(struct stripe_c sc, struct bio bio,
45e621d4 MS	260	uint32_t target_stripe)
7b76ec11 MP	261	{
	262	sector_t begin, end;
	263
4f024f37 KO	264	stripe_map_range_sector(sc, bio->bi_iter.bi_sector,
4f024f37 KO	265	target_stripe, &begin);
f73a1c7d	266	stripe_map_range_sector(sc, bio_end_sector(bio),
7b76ec11 MP	267	target_stripe, &end);
	268	if (begin < end) {
	269	bio->bi_bdev = sc->stripe[target_stripe].dev->bdev;
4f024f37 KO	270	bio->bi_iter.bi_sector = begin +
	271	sc->stripe[target_stripe].physical_start;
	272	bio->bi_iter.bi_size = to_bytes(end - begin);
7b76ec11 MP	273	return DM_MAPIO_REMAPPED;
	274	} else {
	275	/* The range doesn't map to the target stripe */
	276	bio_endio(bio, 0);
	277	return DM_MAPIO_SUBMITTED;
	278	}
	279	}
	280
7de3ee57	281	static int stripe_map(struct dm_target ti, struct bio bio)
1da177e4	282	{
65988525	283	struct stripe_c *sc = ti->private;
374bf7e7	284	uint32_t stripe;
55a62eef	285	unsigned target_bio_nr;
1da177e4	286
d87f4c14	287	if (bio->bi_rw & REQ_FLUSH) {
55a62eef AK	288	target_bio_nr = dm_bio_get_target_bio_nr(bio);
	289	BUG_ON(target_bio_nr >= sc->stripes);
	290	bio->bi_bdev = sc->stripe[target_bio_nr].dev->bdev;
374bf7e7 MP	291	return DM_MAPIO_REMAPPED;
374bf7e7 MP	292	}
45e621d4 MS	293	if (unlikely(bio->bi_rw & REQ_DISCARD) \|\|
45e621d4 MS	294	unlikely(bio->bi_rw & REQ_WRITE_SAME)) {
55a62eef AK	295	target_bio_nr = dm_bio_get_target_bio_nr(bio);
	296	BUG_ON(target_bio_nr >= sc->stripes);
	297	return stripe_map_range(sc, bio, target_bio_nr);
7b76ec11	298	}
374bf7e7	299
4f024f37 KO	300	stripe_map_sector(sc, bio->bi_iter.bi_sector,
4f024f37 KO	301	&stripe, &bio->bi_iter.bi_sector);
1da177e4	302
4f024f37	303	bio->bi_iter.bi_sector += sc->stripe[stripe].physical_start;
1da177e4	304	bio->bi_bdev = sc->stripe[stripe].dev->bdev;
65988525	305
d2a7ad29	306	return DM_MAPIO_REMAPPED;
1da177e4 LT	307	}
1da177e4 LT	308
4f7f5c67 BW	309	/*
	310	* Stripe status:
	311	*
	312	* INFO
	313	* #stripes [stripe_name <stripe_name>] [group word count]
	314	* [error count 'A\|D' <error count 'A\|D'>]
	315	*
	316	* TABLE
	317	* #stripes [stripe chunk size]
	318	* [stripe_name physical_start <stripe_name physical_start>]
	319	*
	320	*/
	321
fd7c092e MP	322	static void stripe_status(struct dm_target *ti, status_type_t type,
fd7c092e MP	323	unsigned status_flags, char *result, unsigned maxlen)
1da177e4 LT	324	{
1da177e4 LT	325	struct stripe_c sc = (struct stripe_c ) ti->private;
4f7f5c67	326	char buffer[sc->stripes + 1];
1da177e4 LT	327	unsigned int sz = 0;
	328	unsigned int i;
	329
	330	switch (type) {
	331	case STATUSTYPE_INFO:
4f7f5c67 BW	332	DMEMIT("%d ", sc->stripes);
	333	for (i = 0; i < sc->stripes; i++) {
	334	DMEMIT("%s ", sc->stripe[i].dev->name);
	335	buffer[i] = atomic_read(&(sc->stripe[i].error_count)) ?
	336	'D' : 'A';
	337	}
	338	buffer[i] = '\0';
	339	DMEMIT("1 %s", buffer);
1da177e4 LT	340	break;
	341
	342	case STATUSTYPE_TABLE:
4ee218cd	343	DMEMIT("%d %llu", sc->stripes,
eb850de6	344	(unsigned long long)sc->chunk_size);
1da177e4	345	for (i = 0; i < sc->stripes; i++)
4ee218cd AM	346	DMEMIT(" %s %llu", sc->stripe[i].dev->name,
4ee218cd AM	347	(unsigned long long)sc->stripe[i].physical_start);
1da177e4 LT	348	break;
1da177e4 LT	349	}
1da177e4 LT	350	}
1da177e4 LT	351
7de3ee57	352	static int stripe_end_io(struct dm_target ti, struct bio bio, int error)
a25eb944 BW	353	{
	354	unsigned i;
	355	char major_minor[16];
	356	struct stripe_c *sc = ti->private;
	357
	358	if (!error)
	359	return 0; /* I/O complete */
	360
7b6d91da	361	if ((error == -EWOULDBLOCK) && (bio->bi_rw & REQ_RAHEAD))
a25eb944 BW	362	return error;
	363
	364	if (error == -EOPNOTSUPP)
	365	return error;
	366
	367	memset(major_minor, 0, sizeof(major_minor));
	368	sprintf(major_minor, "%d:%d",
f331c029 TH	369	MAJOR(disk_devt(bio->bi_bdev->bd_disk)),
f331c029 TH	370	MINOR(disk_devt(bio->bi_bdev->bd_disk)));
a25eb944 BW	371
	372	/*
	373	* Test to see which stripe drive triggered the event
	374	* and increment error count for all stripes on that device.
	375	* If the error count for a given device exceeds the threshold
	376	* value we will no longer trigger any further events.
	377	*/
	378	for (i = 0; i < sc->stripes; i++)
	379	if (!strcmp(sc->stripe[i].dev->name, major_minor)) {
	380	atomic_inc(&(sc->stripe[i].error_count));
	381	if (atomic_read(&(sc->stripe[i].error_count)) <
	382	DM_IO_ERROR_THRESHOLD)
f521f074	383	schedule_work(&sc->trigger_event);
a25eb944 BW	384	}
	385
	386	return error;
	387	}
	388
af4874e0 MS	389	static int stripe_iterate_devices(struct dm_target *ti,
	390	iterate_devices_callout_fn fn, void *data)
	391	{
	392	struct stripe_c *sc = ti->private;
	393	int ret = 0;
	394	unsigned i = 0;
	395
5dea271b	396	do {
af4874e0	397	ret = fn(ti, sc->stripe[i].dev,
5dea271b MS	398	sc->stripe[i].physical_start,
	399	sc->stripe_width, data);
	400	} while (!ret && ++i < sc->stripes);
af4874e0 MS	401
	402	return ret;
	403	}
	404
40bea431 MS	405	static void stripe_io_hints(struct dm_target *ti,
	406	struct queue_limits *limits)
	407	{
	408	struct stripe_c *sc = ti->private;
eb850de6	409	unsigned chunk_size = sc->chunk_size << SECTOR_SHIFT;
40bea431 MS	410
40bea431 MS	411	blk_limits_io_min(limits, chunk_size);
3c5820c7	412	blk_limits_io_opt(limits, chunk_size * sc->stripes);
40bea431 MS	413	}
40bea431 MS	414
29915202 MM	415	static int stripe_merge(struct dm_target ti, struct bvec_merge_data bvm,
	416	struct bio_vec *biovec, int max_size)
	417	{
	418	struct stripe_c *sc = ti->private;
	419	sector_t bvm_sector = bvm->bi_sector;
	420	uint32_t stripe;
	421	struct request_queue *q;
	422
	423	stripe_map_sector(sc, bvm_sector, &stripe, &bvm_sector);
	424
	425	q = bdev_get_queue(sc->stripe[stripe].dev->bdev);
	426	if (!q->merge_bvec_fn)
	427	return max_size;
	428
	429	bvm->bi_bdev = sc->stripe[stripe].dev->bdev;
	430	bvm->bi_sector = sc->stripe[stripe].physical_start + bvm_sector;
	431
	432	return min(max_size, q->merge_bvec_fn(q, bvm, biovec));
	433	}
	434
1da177e4 LT	435	static struct target_type stripe_target = {
1da177e4 LT	436	.name = "striped",
fd7c092e	437	.version = {1, 5, 1},
1da177e4 LT	438	.module = THIS_MODULE,
	439	.ctr = stripe_ctr,
	440	.dtr = stripe_dtr,
	441	.map = stripe_map,
a25eb944	442	.end_io = stripe_end_io,
1da177e4	443	.status = stripe_status,
af4874e0	444	.iterate_devices = stripe_iterate_devices,
40bea431	445	.io_hints = stripe_io_hints,
29915202	446	.merge = stripe_merge,
1da177e4 LT	447	};
	448
	449	int __init dm_stripe_init(void)
	450	{
	451	int r;
	452
	453	r = dm_register_target(&stripe_target);
6edebdee	454	if (r < 0) {
72d94861	455	DMWARN("target registration failed");
6edebdee HM	456	return r;
6edebdee HM	457	}
1da177e4 LT	458
	459	return r;
	460	}
	461
	462	void dm_stripe_exit(void)
	463	{
10d3bd09	464	dm_unregister_target(&stripe_target);
1da177e4	465	}