[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_requests = stripes;
	ti->num_discard_requests = 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_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;

	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_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,
			 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;
	}
	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;
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
374bf7e7	163	ti->num_flush_requests = stripes;
7b76ec11	164	ti->num_discard_requests = stripes;
1da177e4	165
eb850de6	166	sc->chunk_size = chunk_size;
33d07c0d MP	167	if (chunk_size & (chunk_size - 1))
	168	sc->chunk_size_shift = -1;
	169	else
	170	sc->chunk_size_shift = __ffs(chunk_size);
1da177e4 LT	171
	172	/*
	173	* Get the stripe destinations.
	174	*/
	175	for (i = 0; i < stripes; i++) {
	176	argv += 2;
	177
	178	r = get_stripe(ti, sc, i, argv);
	179	if (r < 0) {
72d94861	180	ti->error = "Couldn't parse stripe destination";
1da177e4 LT	181	while (i--)
	182	dm_put_device(ti, sc->stripe[i].dev);
	183	kfree(sc);
	184	return r;
	185	}
a25eb944	186	atomic_set(&(sc->stripe[i].error_count), 0);
1da177e4 LT	187	}
	188
	189	ti->private = sc;
a25eb944	190
1da177e4 LT	191	return 0;
	192	}
	193
	194	static void stripe_dtr(struct dm_target *ti)
	195	{
	196	unsigned int i;
	197	struct stripe_c sc = (struct stripe_c ) ti->private;
	198
	199	for (i = 0; i < sc->stripes; i++)
	200	dm_put_device(ti, sc->stripe[i].dev);
	201
f521f074	202	flush_work_sync(&sc->trigger_event);
1da177e4 LT	203	kfree(sc);
	204	}
	205
65988525 MP	206	static void stripe_map_sector(struct stripe_c *sc, sector_t sector,
	207	uint32_t stripe, sector_t result)
	208	{
eb850de6	209	sector_t chunk = dm_target_offset(sc->ti, sector);
33d07c0d MP	210	sector_t chunk_offset;
	211
	212	if (sc->chunk_size_shift < 0)
	213	chunk_offset = sector_div(chunk, sc->chunk_size);
	214	else {
	215	chunk_offset = chunk & (sc->chunk_size - 1);
	216	chunk >>= sc->chunk_size_shift;
	217	}
65988525	218
c96053b7 MP	219	if (sc->stripes_shift < 0)
	220	*stripe = sector_div(chunk, sc->stripes);
	221	else {
1df05483	222	*stripe = chunk & (sc->stripes - 1);
c96053b7 MP	223	chunk >>= sc->stripes_shift;
	224	}
	225
33d07c0d MP	226	if (sc->chunk_size_shift < 0)
	227	chunk *= sc->chunk_size;
	228	else
	229	chunk <<= sc->chunk_size_shift;
	230
	231	*result = chunk + chunk_offset;
65988525 MP	232	}
65988525 MP	233
7b76ec11 MP	234	static void stripe_map_range_sector(struct stripe_c *sc, sector_t sector,
	235	uint32_t target_stripe, sector_t *result)
	236	{
	237	uint32_t stripe;
	238
	239	stripe_map_sector(sc, sector, &stripe, result);
	240	if (stripe == target_stripe)
	241	return;
eb850de6 MS	242
	243	/* round down */
	244	sector = *result;
33d07c0d MP	245	if (sc->chunk_size_shift < 0)
	246	*result -= sector_div(sector, sc->chunk_size);
	247	else
	248	*result = sector & ~(sector_t)(sc->chunk_size - 1);
eb850de6	249
7b76ec11	250	if (target_stripe < stripe)
eb850de6	251	result += sc->chunk_size; / next chunk */
7b76ec11 MP	252	}
	253
	254	static int stripe_map_discard(struct stripe_c sc, struct bio bio,
	255	uint32_t target_stripe)
	256	{
	257	sector_t begin, end;
	258
	259	stripe_map_range_sector(sc, bio->bi_sector, target_stripe, &begin);
	260	stripe_map_range_sector(sc, bio->bi_sector + bio_sectors(bio),
	261	target_stripe, &end);
	262	if (begin < end) {
	263	bio->bi_bdev = sc->stripe[target_stripe].dev->bdev;
	264	bio->bi_sector = begin + sc->stripe[target_stripe].physical_start;
	265	bio->bi_size = to_bytes(end - begin);
	266	return DM_MAPIO_REMAPPED;
	267	} else {
	268	/* The range doesn't map to the target stripe */
	269	bio_endio(bio, 0);
	270	return DM_MAPIO_SUBMITTED;
	271	}
	272	}
	273
1da177e4 LT	274	static int stripe_map(struct dm_target ti, struct bio bio,
	275	union map_info *map_context)
	276	{
65988525	277	struct stripe_c *sc = ti->private;
374bf7e7	278	uint32_t stripe;
57cba5d3	279	unsigned target_request_nr;
1da177e4	280
d87f4c14	281	if (bio->bi_rw & REQ_FLUSH) {
57cba5d3 MS	282	target_request_nr = map_context->target_request_nr;
	283	BUG_ON(target_request_nr >= sc->stripes);
	284	bio->bi_bdev = sc->stripe[target_request_nr].dev->bdev;
374bf7e7 MP	285	return DM_MAPIO_REMAPPED;
374bf7e7 MP	286	}
7b76ec11 MP	287	if (unlikely(bio->bi_rw & REQ_DISCARD)) {
	288	target_request_nr = map_context->target_request_nr;
	289	BUG_ON(target_request_nr >= sc->stripes);
	290	return stripe_map_discard(sc, bio, target_request_nr);
	291	}
374bf7e7	292
65988525	293	stripe_map_sector(sc, bio->bi_sector, &stripe, &bio->bi_sector);
1da177e4	294
65988525	295	bio->bi_sector += sc->stripe[stripe].physical_start;
1da177e4	296	bio->bi_bdev = sc->stripe[stripe].dev->bdev;
65988525	297
d2a7ad29	298	return DM_MAPIO_REMAPPED;
1da177e4 LT	299	}
1da177e4 LT	300
4f7f5c67 BW	301	/*
	302	* Stripe status:
	303	*
	304	* INFO
	305	* #stripes [stripe_name <stripe_name>] [group word count]
	306	* [error count 'A\|D' <error count 'A\|D'>]
	307	*
	308	* TABLE
	309	* #stripes [stripe chunk size]
	310	* [stripe_name physical_start <stripe_name physical_start>]
	311	*
	312	*/
	313
1f4e0ff0 AK	314	static int stripe_status(struct dm_target *ti, status_type_t type,
1f4e0ff0 AK	315	unsigned status_flags, char *result, unsigned maxlen)
1da177e4 LT	316	{
1da177e4 LT	317	struct stripe_c sc = (struct stripe_c ) ti->private;
4f7f5c67	318	char buffer[sc->stripes + 1];
1da177e4 LT	319	unsigned int sz = 0;
	320	unsigned int i;
	321
	322	switch (type) {
	323	case STATUSTYPE_INFO:
4f7f5c67 BW	324	DMEMIT("%d ", sc->stripes);
	325	for (i = 0; i < sc->stripes; i++) {
	326	DMEMIT("%s ", sc->stripe[i].dev->name);
	327	buffer[i] = atomic_read(&(sc->stripe[i].error_count)) ?
	328	'D' : 'A';
	329	}
	330	buffer[i] = '\0';
	331	DMEMIT("1 %s", buffer);
1da177e4 LT	332	break;
	333
	334	case STATUSTYPE_TABLE:
4ee218cd	335	DMEMIT("%d %llu", sc->stripes,
eb850de6	336	(unsigned long long)sc->chunk_size);
1da177e4	337	for (i = 0; i < sc->stripes; i++)
4ee218cd AM	338	DMEMIT(" %s %llu", sc->stripe[i].dev->name,
4ee218cd AM	339	(unsigned long long)sc->stripe[i].physical_start);
1da177e4 LT	340	break;
	341	}
	342	return 0;
	343	}
	344
a25eb944 BW	345	static int stripe_end_io(struct dm_target ti, struct bio bio,
	346	int error, union map_info *map_context)
	347	{
	348	unsigned i;
	349	char major_minor[16];
	350	struct stripe_c *sc = ti->private;
	351
	352	if (!error)
	353	return 0; /* I/O complete */
	354
7b6d91da	355	if ((error == -EWOULDBLOCK) && (bio->bi_rw & REQ_RAHEAD))
a25eb944 BW	356	return error;
	357
	358	if (error == -EOPNOTSUPP)
	359	return error;
	360
	361	memset(major_minor, 0, sizeof(major_minor));
	362	sprintf(major_minor, "%d:%d",
f331c029 TH	363	MAJOR(disk_devt(bio->bi_bdev->bd_disk)),
f331c029 TH	364	MINOR(disk_devt(bio->bi_bdev->bd_disk)));
a25eb944 BW	365
	366	/*
	367	* Test to see which stripe drive triggered the event
	368	* and increment error count for all stripes on that device.
	369	* If the error count for a given device exceeds the threshold
	370	* value we will no longer trigger any further events.
	371	*/
	372	for (i = 0; i < sc->stripes; i++)
	373	if (!strcmp(sc->stripe[i].dev->name, major_minor)) {
	374	atomic_inc(&(sc->stripe[i].error_count));
	375	if (atomic_read(&(sc->stripe[i].error_count)) <
	376	DM_IO_ERROR_THRESHOLD)
f521f074	377	schedule_work(&sc->trigger_event);
a25eb944 BW	378	}
	379
	380	return error;
	381	}
	382
af4874e0 MS	383	static int stripe_iterate_devices(struct dm_target *ti,
	384	iterate_devices_callout_fn fn, void *data)
	385	{
	386	struct stripe_c *sc = ti->private;
	387	int ret = 0;
	388	unsigned i = 0;
	389
5dea271b	390	do {
af4874e0	391	ret = fn(ti, sc->stripe[i].dev,
5dea271b MS	392	sc->stripe[i].physical_start,
	393	sc->stripe_width, data);
	394	} while (!ret && ++i < sc->stripes);
af4874e0 MS	395
	396	return ret;
	397	}
	398
40bea431 MS	399	static void stripe_io_hints(struct dm_target *ti,
	400	struct queue_limits *limits)
	401	{
	402	struct stripe_c *sc = ti->private;
eb850de6	403	unsigned chunk_size = sc->chunk_size << SECTOR_SHIFT;
40bea431 MS	404
40bea431 MS	405	blk_limits_io_min(limits, chunk_size);
3c5820c7	406	blk_limits_io_opt(limits, chunk_size * sc->stripes);
40bea431 MS	407	}
40bea431 MS	408
29915202 MM	409	static int stripe_merge(struct dm_target ti, struct bvec_merge_data bvm,
	410	struct bio_vec *biovec, int max_size)
	411	{
	412	struct stripe_c *sc = ti->private;
	413	sector_t bvm_sector = bvm->bi_sector;
	414	uint32_t stripe;
	415	struct request_queue *q;
	416
	417	stripe_map_sector(sc, bvm_sector, &stripe, &bvm_sector);
	418
	419	q = bdev_get_queue(sc->stripe[stripe].dev->bdev);
	420	if (!q->merge_bvec_fn)
	421	return max_size;
	422
	423	bvm->bi_bdev = sc->stripe[stripe].dev->bdev;
	424	bvm->bi_sector = sc->stripe[stripe].physical_start + bvm_sector;
	425
	426	return min(max_size, q->merge_bvec_fn(q, bvm, biovec));
	427	}
	428
1da177e4 LT	429	static struct target_type stripe_target = {
1da177e4 LT	430	.name = "striped",
eb850de6	431	.version = {1, 5, 0},
1da177e4 LT	432	.module = THIS_MODULE,
	433	.ctr = stripe_ctr,
	434	.dtr = stripe_dtr,
	435	.map = stripe_map,
a25eb944	436	.end_io = stripe_end_io,
1da177e4	437	.status = stripe_status,
af4874e0	438	.iterate_devices = stripe_iterate_devices,
40bea431	439	.io_hints = stripe_io_hints,
29915202	440	.merge = stripe_merge,
1da177e4 LT	441	};
	442
	443	int __init dm_stripe_init(void)
	444	{
	445	int r;
	446
	447	r = dm_register_target(&stripe_target);
6edebdee	448	if (r < 0) {
72d94861	449	DMWARN("target registration failed");
6edebdee HM	450	return r;
6edebdee HM	451	}
1da177e4 LT	452
	453	return r;
	454	}
	455
	456	void dm_stripe_exit(void)
	457	{
10d3bd09	458	dm_unregister_target(&stripe_target);
1da177e4	459	}