[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;
	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;
	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_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_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_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)
{
	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_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 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
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;
33d07c0d	34	int chunk_size_shift;
1da177e4	35
a25eb944 BW	36	/* Needed for handling events */
	37	struct dm_target *ti;
	38
	39	/* Work struct used for triggering events*/
f521f074	40	struct work_struct trigger_event;
a25eb944	41
1da177e4 LT	42	struct stripe stripe[0];
	43	};
	44
a25eb944 BW	45	/*
	46	* An event is triggered whenever a drive
	47	* drops out of a stripe volume.
	48	*/
	49	static void trigger_event(struct work_struct *work)
	50	{
f521f074 TH	51	struct stripe_c *sc = container_of(work, struct stripe_c,
f521f074 TH	52	trigger_event);
a25eb944	53	dm_table_event(sc->ti->table);
a25eb944 BW	54	}
a25eb944 BW	55
1da177e4 LT	56	static inline struct stripe_c *alloc_context(unsigned int stripes)
	57	{
	58	size_t len;
	59
d63a5ce3 MP	60	if (dm_array_too_big(sizeof(struct stripe_c), sizeof(struct stripe),
d63a5ce3 MP	61	stripes))
1da177e4 LT	62	return NULL;
	63
	64	len = sizeof(struct stripe_c) + (sizeof(struct stripe) * stripes);
	65
	66	return kmalloc(len, GFP_KERNEL);
	67	}
	68
	69	/*
	70	* Parse a single <dev> <sector> pair
	71	*/
	72	static int get_stripe(struct dm_target ti, struct stripe_c sc,
	73	unsigned int stripe, char **argv)
	74	{
4ee218cd	75	unsigned long long start;
31998ef1	76	char dummy;
1da177e4	77
31998ef1	78	if (sscanf(argv[1], "%llu%c", &start, &dummy) != 1)
1da177e4 LT	79	return -EINVAL;
1da177e4 LT	80
8215d6ec	81	if (dm_get_device(ti, argv[0], dm_table_get_mode(ti->table),
1da177e4 LT	82	&sc->stripe[stripe].dev))
	83	return -ENXIO;
	84
	85	sc->stripe[stripe].physical_start = start;
a25eb944	86
1da177e4 LT	87	return 0;
	88	}
	89
	90	/*
	91	* Construct a striped mapping.
eb850de6	92	* <number of stripes> <chunk size> [<dev_path> <offset>]+
1da177e4 LT	93	*/
	94	static int stripe_ctr(struct dm_target ti, unsigned int argc, char *argv)
	95	{
	96	struct stripe_c *sc;
	97	sector_t width;
	98	uint32_t stripes;
	99	uint32_t chunk_size;
1da177e4 LT	100	int r;
	101	unsigned int i;
	102
	103	if (argc < 2) {
72d94861	104	ti->error = "Not enough arguments";
1da177e4 LT	105	return -EINVAL;
	106	}
	107
1a66a08a	108	if (kstrtouint(argv[0], 10, &stripes) \|\| !stripes) {
72d94861	109	ti->error = "Invalid stripe count";
1da177e4 LT	110	return -EINVAL;
	111	}
	112
8f069b41	113	if (kstrtouint(argv[1], 10, &chunk_size) \|\| !chunk_size) {
eb850de6	114	ti->error = "Invalid chunk_size";
1da177e4 LT	115	return -EINVAL;
	116	}
	117
eb850de6 MS	118	width = ti->len;
eb850de6 MS	119	if (sector_div(width, chunk_size)) {
72d94861	120	ti->error = "Target length not divisible by "
8ba32fde KC	121	"chunk size";
	122	return -EINVAL;
	123	}
	124
1da177e4	125	if (sector_div(width, stripes)) {
72d94861	126	ti->error = "Target length not divisible by "
1da177e4 LT	127	"number of stripes";
	128	return -EINVAL;
	129	}
	130
	131	/*
	132	* Do we have enough arguments for that many stripes ?
	133	*/
	134	if (argc != (2 + 2 * stripes)) {
72d94861	135	ti->error = "Not enough destinations "
1da177e4 LT	136	"specified";
	137	return -EINVAL;
	138	}
	139
	140	sc = alloc_context(stripes);
	141	if (!sc) {
72d94861	142	ti->error = "Memory allocation for striped context "
1da177e4 LT	143	"failed";
	144	return -ENOMEM;
	145	}
	146
f521f074	147	INIT_WORK(&sc->trigger_event, trigger_event);
a25eb944 BW	148
	149	/* Set pointer to dm target; used in trigger_event */
	150	sc->ti = ti;
1da177e4 LT	151	sc->stripes = stripes;
1da177e4 LT	152	sc->stripe_width = width;
c96053b7 MP	153
	154	if (stripes & (stripes - 1))
	155	sc->stripes_shift = -1;
1df05483 MP	156	else
1df05483 MP	157	sc->stripes_shift = __ffs(stripes);
c96053b7	158
542f9038 MS	159	r = dm_set_target_max_io_len(ti, chunk_size);
	160	if (r)
	161	return r;
	162
55a62eef AK	163	ti->num_flush_bios = stripes;
	164	ti->num_discard_bios = stripes;
	165	ti->num_write_same_bios = stripes;
1da177e4	166
eb850de6	167	sc->chunk_size = chunk_size;
33d07c0d MP	168	if (chunk_size & (chunk_size - 1))
	169	sc->chunk_size_shift = -1;
	170	else
	171	sc->chunk_size_shift = __ffs(chunk_size);
1da177e4 LT	172
	173	/*
	174	* Get the stripe destinations.
	175	*/
	176	for (i = 0; i < stripes; i++) {
	177	argv += 2;
	178
	179	r = get_stripe(ti, sc, i, argv);
	180	if (r < 0) {
72d94861	181	ti->error = "Couldn't parse stripe destination";
1da177e4 LT	182	while (i--)
	183	dm_put_device(ti, sc->stripe[i].dev);
	184	kfree(sc);
	185	return r;
	186	}
a25eb944	187	atomic_set(&(sc->stripe[i].error_count), 0);
1da177e4 LT	188	}
	189
	190	ti->private = sc;
a25eb944	191
1da177e4 LT	192	return 0;
	193	}
	194
	195	static void stripe_dtr(struct dm_target *ti)
	196	{
	197	unsigned int i;
	198	struct stripe_c sc = (struct stripe_c ) ti->private;
	199
	200	for (i = 0; i < sc->stripes; i++)
	201	dm_put_device(ti, sc->stripe[i].dev);
	202
43829731	203	flush_work(&sc->trigger_event);
1da177e4 LT	204	kfree(sc);
	205	}
	206
65988525 MP	207	static void stripe_map_sector(struct stripe_c *sc, sector_t sector,
	208	uint32_t stripe, sector_t result)
	209	{
eb850de6	210	sector_t chunk = dm_target_offset(sc->ti, sector);
33d07c0d MP	211	sector_t chunk_offset;
	212
	213	if (sc->chunk_size_shift < 0)
	214	chunk_offset = sector_div(chunk, sc->chunk_size);
	215	else {
	216	chunk_offset = chunk & (sc->chunk_size - 1);
	217	chunk >>= sc->chunk_size_shift;
	218	}
65988525	219
c96053b7 MP	220	if (sc->stripes_shift < 0)
	221	*stripe = sector_div(chunk, sc->stripes);
	222	else {
1df05483	223	*stripe = chunk & (sc->stripes - 1);
c96053b7 MP	224	chunk >>= sc->stripes_shift;
	225	}
	226
33d07c0d MP	227	if (sc->chunk_size_shift < 0)
	228	chunk *= sc->chunk_size;
	229	else
	230	chunk <<= sc->chunk_size_shift;
	231
	232	*result = chunk + chunk_offset;
65988525 MP	233	}
65988525 MP	234
7b76ec11 MP	235	static void stripe_map_range_sector(struct stripe_c *sc, sector_t sector,
	236	uint32_t target_stripe, sector_t *result)
	237	{
	238	uint32_t stripe;
	239
	240	stripe_map_sector(sc, sector, &stripe, result);
	241	if (stripe == target_stripe)
	242	return;
eb850de6 MS	243
	244	/* round down */
	245	sector = *result;
33d07c0d MP	246	if (sc->chunk_size_shift < 0)
	247	*result -= sector_div(sector, sc->chunk_size);
	248	else
	249	*result = sector & ~(sector_t)(sc->chunk_size - 1);
eb850de6	250
7b76ec11	251	if (target_stripe < stripe)
eb850de6	252	result += sc->chunk_size; / next chunk */
7b76ec11 MP	253	}
7b76ec11 MP	254
45e621d4 MS	255	static int stripe_map_range(struct stripe_c sc, struct bio bio,
45e621d4 MS	256	uint32_t target_stripe)
7b76ec11 MP	257	{
	258	sector_t begin, end;
	259
	260	stripe_map_range_sector(sc, bio->bi_sector, target_stripe, &begin);
f73a1c7d	261	stripe_map_range_sector(sc, bio_end_sector(bio),
7b76ec11 MP	262	target_stripe, &end);
	263	if (begin < end) {
	264	bio->bi_bdev = sc->stripe[target_stripe].dev->bdev;
	265	bio->bi_sector = begin + sc->stripe[target_stripe].physical_start;
	266	bio->bi_size = to_bytes(end - begin);
	267	return DM_MAPIO_REMAPPED;
	268	} else {
	269	/* The range doesn't map to the target stripe */
	270	bio_endio(bio, 0);
	271	return DM_MAPIO_SUBMITTED;
	272	}
	273	}
	274
7de3ee57	275	static int stripe_map(struct dm_target ti, struct bio bio)
1da177e4	276	{
65988525	277	struct stripe_c *sc = ti->private;
374bf7e7	278	uint32_t stripe;
55a62eef	279	unsigned target_bio_nr;
1da177e4	280
d87f4c14	281	if (bio->bi_rw & REQ_FLUSH) {
55a62eef AK	282	target_bio_nr = dm_bio_get_target_bio_nr(bio);
	283	BUG_ON(target_bio_nr >= sc->stripes);
	284	bio->bi_bdev = sc->stripe[target_bio_nr].dev->bdev;
374bf7e7 MP	285	return DM_MAPIO_REMAPPED;
374bf7e7 MP	286	}
45e621d4 MS	287	if (unlikely(bio->bi_rw & REQ_DISCARD) \|\|
45e621d4 MS	288	unlikely(bio->bi_rw & REQ_WRITE_SAME)) {
55a62eef AK	289	target_bio_nr = dm_bio_get_target_bio_nr(bio);
	290	BUG_ON(target_bio_nr >= sc->stripes);
	291	return stripe_map_range(sc, bio, target_bio_nr);
7b76ec11	292	}
374bf7e7	293
65988525	294	stripe_map_sector(sc, bio->bi_sector, &stripe, &bio->bi_sector);
1da177e4	295
65988525	296	bio->bi_sector += sc->stripe[stripe].physical_start;
1da177e4	297	bio->bi_bdev = sc->stripe[stripe].dev->bdev;
65988525	298
d2a7ad29	299	return DM_MAPIO_REMAPPED;
1da177e4 LT	300	}
1da177e4 LT	301
4f7f5c67 BW	302	/*
	303	* Stripe status:
	304	*
	305	* INFO
	306	* #stripes [stripe_name <stripe_name>] [group word count]
	307	* [error count 'A\|D' <error count 'A\|D'>]
	308	*
	309	* TABLE
	310	* #stripes [stripe chunk size]
	311	* [stripe_name physical_start <stripe_name physical_start>]
	312	*
	313	*/
	314
fd7c092e MP	315	static void stripe_status(struct dm_target *ti, status_type_t type,
fd7c092e MP	316	unsigned status_flags, char *result, unsigned maxlen)
1da177e4 LT	317	{
1da177e4 LT	318	struct stripe_c sc = (struct stripe_c ) ti->private;
4f7f5c67	319	char buffer[sc->stripes + 1];
1da177e4 LT	320	unsigned int sz = 0;
	321	unsigned int i;
	322
	323	switch (type) {
	324	case STATUSTYPE_INFO:
4f7f5c67 BW	325	DMEMIT("%d ", sc->stripes);
	326	for (i = 0; i < sc->stripes; i++) {
	327	DMEMIT("%s ", sc->stripe[i].dev->name);
	328	buffer[i] = atomic_read(&(sc->stripe[i].error_count)) ?
	329	'D' : 'A';
	330	}
	331	buffer[i] = '\0';
	332	DMEMIT("1 %s", buffer);
1da177e4 LT	333	break;
	334
	335	case STATUSTYPE_TABLE:
4ee218cd	336	DMEMIT("%d %llu", sc->stripes,
eb850de6	337	(unsigned long long)sc->chunk_size);
1da177e4	338	for (i = 0; i < sc->stripes; i++)
4ee218cd AM	339	DMEMIT(" %s %llu", sc->stripe[i].dev->name,
4ee218cd AM	340	(unsigned long long)sc->stripe[i].physical_start);
1da177e4 LT	341	break;
1da177e4 LT	342	}
1da177e4 LT	343	}
1da177e4 LT	344
7de3ee57	345	static int stripe_end_io(struct dm_target ti, struct bio bio, int error)
a25eb944 BW	346	{
	347	unsigned i;
	348	char major_minor[16];
	349	struct stripe_c *sc = ti->private;
	350
	351	if (!error)
	352	return 0; /* I/O complete */
	353
7b6d91da	354	if ((error == -EWOULDBLOCK) && (bio->bi_rw & REQ_RAHEAD))
a25eb944 BW	355	return error;
	356
	357	if (error == -EOPNOTSUPP)
	358	return error;
	359
	360	memset(major_minor, 0, sizeof(major_minor));
	361	sprintf(major_minor, "%d:%d",
f331c029 TH	362	MAJOR(disk_devt(bio->bi_bdev->bd_disk)),
f331c029 TH	363	MINOR(disk_devt(bio->bi_bdev->bd_disk)));
a25eb944 BW	364
	365	/*
	366	* Test to see which stripe drive triggered the event
	367	* and increment error count for all stripes on that device.
	368	* If the error count for a given device exceeds the threshold
	369	* value we will no longer trigger any further events.
	370	*/
	371	for (i = 0; i < sc->stripes; i++)
	372	if (!strcmp(sc->stripe[i].dev->name, major_minor)) {
	373	atomic_inc(&(sc->stripe[i].error_count));
	374	if (atomic_read(&(sc->stripe[i].error_count)) <
	375	DM_IO_ERROR_THRESHOLD)
f521f074	376	schedule_work(&sc->trigger_event);
a25eb944 BW	377	}
	378
	379	return error;
	380	}
	381
af4874e0 MS	382	static int stripe_iterate_devices(struct dm_target *ti,
	383	iterate_devices_callout_fn fn, void *data)
	384	{
	385	struct stripe_c *sc = ti->private;
	386	int ret = 0;
	387	unsigned i = 0;
	388
5dea271b	389	do {
af4874e0	390	ret = fn(ti, sc->stripe[i].dev,
5dea271b MS	391	sc->stripe[i].physical_start,
	392	sc->stripe_width, data);
	393	} while (!ret && ++i < sc->stripes);
af4874e0 MS	394
	395	return ret;
	396	}
	397
40bea431 MS	398	static void stripe_io_hints(struct dm_target *ti,
	399	struct queue_limits *limits)
	400	{
	401	struct stripe_c *sc = ti->private;
eb850de6	402	unsigned chunk_size = sc->chunk_size << SECTOR_SHIFT;
40bea431 MS	403
40bea431 MS	404	blk_limits_io_min(limits, chunk_size);
3c5820c7	405	blk_limits_io_opt(limits, chunk_size * sc->stripes);
40bea431 MS	406	}
40bea431 MS	407
29915202 MM	408	static int stripe_merge(struct dm_target ti, struct bvec_merge_data bvm,
	409	struct bio_vec *biovec, int max_size)
	410	{
	411	struct stripe_c *sc = ti->private;
	412	sector_t bvm_sector = bvm->bi_sector;
	413	uint32_t stripe;
	414	struct request_queue *q;
	415
	416	stripe_map_sector(sc, bvm_sector, &stripe, &bvm_sector);
	417
	418	q = bdev_get_queue(sc->stripe[stripe].dev->bdev);
	419	if (!q->merge_bvec_fn)
	420	return max_size;
	421
	422	bvm->bi_bdev = sc->stripe[stripe].dev->bdev;
	423	bvm->bi_sector = sc->stripe[stripe].physical_start + bvm_sector;
	424
	425	return min(max_size, q->merge_bvec_fn(q, bvm, biovec));
	426	}
	427
1da177e4 LT	428	static struct target_type stripe_target = {
1da177e4 LT	429	.name = "striped",
fd7c092e	430	.version = {1, 5, 1},
1da177e4 LT	431	.module = THIS_MODULE,
	432	.ctr = stripe_ctr,
	433	.dtr = stripe_dtr,
	434	.map = stripe_map,
a25eb944	435	.end_io = stripe_end_io,
1da177e4	436	.status = stripe_status,
af4874e0	437	.iterate_devices = stripe_iterate_devices,
40bea431	438	.io_hints = stripe_io_hints,
29915202	439	.merge = stripe_merge,
1da177e4 LT	440	};
	441
	442	int __init dm_stripe_init(void)
	443	{
	444	int r;
	445
	446	r = dm_register_target(&stripe_target);
6edebdee	447	if (r < 0) {
72d94861	448	DMWARN("target registration failed");
6edebdee HM	449	return r;
6edebdee HM	450	}
1da177e4 LT	451
	452	return r;
	453	}
	454
	455	void dm_stripe_exit(void)
	456	{
10d3bd09	457	dm_unregister_target(&stripe_target);
1da177e4	458	}