[linux.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;
	int ret;

	if (sscanf(argv[1], "%llu%c", &start, &dummy) != 1)
		return -EINVAL;

	ret = dm_get_device(ti, argv[0], dm_table_get_mode(ti->table),
			    &sc->stripe[stripe].dev);
	if (ret)
		return ret;

	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);
		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 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,
};

int __init dm_stripe_init(void)
{
	int r;

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

	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;
e80d1c80	78	int ret;
1da177e4	79
31998ef1	80	if (sscanf(argv[1], "%llu%c", &start, &dummy) != 1)
1da177e4 LT	81	return -EINVAL;
1da177e4 LT	82
e80d1c80 VG	83	ret = dm_get_device(ti, argv[0], dm_table_get_mode(ti->table),
	84	&sc->stripe[stripe].dev);
	85	if (ret)
	86	return ret;
1da177e4 LT	87
1da177e4 LT	88	sc->stripe[stripe].physical_start = start;
a25eb944	89
1da177e4 LT	90	return 0;
	91	}
	92
	93	/*
	94	* Construct a striped mapping.
eb850de6	95	* <number of stripes> <chunk size> [<dev_path> <offset>]+
1da177e4 LT	96	*/
	97	static int stripe_ctr(struct dm_target ti, unsigned int argc, char *argv)
	98	{
	99	struct stripe_c *sc;
d793e684	100	sector_t width, tmp_len;
1da177e4 LT	101	uint32_t stripes;
1da177e4 LT	102	uint32_t chunk_size;
1da177e4 LT	103	int r;
	104	unsigned int i;
	105
	106	if (argc < 2) {
72d94861	107	ti->error = "Not enough arguments";
1da177e4 LT	108	return -EINVAL;
	109	}
	110
1a66a08a	111	if (kstrtouint(argv[0], 10, &stripes) \|\| !stripes) {
72d94861	112	ti->error = "Invalid stripe count";
1da177e4 LT	113	return -EINVAL;
	114	}
	115
8f069b41	116	if (kstrtouint(argv[1], 10, &chunk_size) \|\| !chunk_size) {
eb850de6	117	ti->error = "Invalid chunk_size";
1da177e4 LT	118	return -EINVAL;
	119	}
	120
eb850de6	121	width = ti->len;
d793e684	122	if (sector_div(width, stripes)) {
72d94861	123	ti->error = "Target length not divisible by "
d793e684	124	"number of stripes";
8ba32fde KC	125	return -EINVAL;
	126	}
	127
d793e684 MS	128	tmp_len = width;
d793e684 MS	129	if (sector_div(tmp_len, chunk_size)) {
72d94861	130	ti->error = "Target length not divisible by "
d793e684	131	"chunk size";
1da177e4 LT	132	return -EINVAL;
	133	}
	134
	135	/*
	136	* Do we have enough arguments for that many stripes ?
	137	*/
	138	if (argc != (2 + 2 * stripes)) {
72d94861	139	ti->error = "Not enough destinations "
1da177e4 LT	140	"specified";
	141	return -EINVAL;
	142	}
	143
	144	sc = alloc_context(stripes);
	145	if (!sc) {
72d94861	146	ti->error = "Memory allocation for striped context "
1da177e4 LT	147	"failed";
	148	return -ENOMEM;
	149	}
	150
f521f074	151	INIT_WORK(&sc->trigger_event, trigger_event);
a25eb944 BW	152
	153	/* Set pointer to dm target; used in trigger_event */
	154	sc->ti = ti;
1da177e4 LT	155	sc->stripes = stripes;
1da177e4 LT	156	sc->stripe_width = width;
c96053b7 MP	157
	158	if (stripes & (stripes - 1))
	159	sc->stripes_shift = -1;
1df05483 MP	160	else
1df05483 MP	161	sc->stripes_shift = __ffs(stripes);
c96053b7	162
542f9038	163	r = dm_set_target_max_io_len(ti, chunk_size);
a3f2af25 PK	164	if (r) {
a3f2af25 PK	165	kfree(sc);
542f9038	166	return r;
a3f2af25	167	}
542f9038	168
55a62eef AK	169	ti->num_flush_bios = stripes;
	170	ti->num_discard_bios = stripes;
	171	ti->num_write_same_bios = stripes;
1da177e4	172
eb850de6	173	sc->chunk_size = chunk_size;
33d07c0d MP	174	if (chunk_size & (chunk_size - 1))
	175	sc->chunk_size_shift = -1;
	176	else
	177	sc->chunk_size_shift = __ffs(chunk_size);
1da177e4 LT	178
	179	/*
	180	* Get the stripe destinations.
	181	*/
	182	for (i = 0; i < stripes; i++) {
	183	argv += 2;
	184
	185	r = get_stripe(ti, sc, i, argv);
	186	if (r < 0) {
72d94861	187	ti->error = "Couldn't parse stripe destination";
1da177e4 LT	188	while (i--)
	189	dm_put_device(ti, sc->stripe[i].dev);
	190	kfree(sc);
	191	return r;
	192	}
a25eb944	193	atomic_set(&(sc->stripe[i].error_count), 0);
1da177e4 LT	194	}
	195
	196	ti->private = sc;
a25eb944	197
1da177e4 LT	198	return 0;
	199	}
	200
	201	static void stripe_dtr(struct dm_target *ti)
	202	{
	203	unsigned int i;
	204	struct stripe_c sc = (struct stripe_c ) ti->private;
	205
	206	for (i = 0; i < sc->stripes; i++)
	207	dm_put_device(ti, sc->stripe[i].dev);
	208
43829731	209	flush_work(&sc->trigger_event);
1da177e4 LT	210	kfree(sc);
	211	}
	212
65988525 MP	213	static void stripe_map_sector(struct stripe_c *sc, sector_t sector,
	214	uint32_t stripe, sector_t result)
	215	{
eb850de6	216	sector_t chunk = dm_target_offset(sc->ti, sector);
33d07c0d MP	217	sector_t chunk_offset;
	218
	219	if (sc->chunk_size_shift < 0)
	220	chunk_offset = sector_div(chunk, sc->chunk_size);
	221	else {
	222	chunk_offset = chunk & (sc->chunk_size - 1);
	223	chunk >>= sc->chunk_size_shift;
	224	}
65988525	225
c96053b7 MP	226	if (sc->stripes_shift < 0)
	227	*stripe = sector_div(chunk, sc->stripes);
	228	else {
1df05483	229	*stripe = chunk & (sc->stripes - 1);
c96053b7 MP	230	chunk >>= sc->stripes_shift;
	231	}
	232
33d07c0d MP	233	if (sc->chunk_size_shift < 0)
	234	chunk *= sc->chunk_size;
	235	else
	236	chunk <<= sc->chunk_size_shift;
	237
	238	*result = chunk + chunk_offset;
65988525 MP	239	}
65988525 MP	240
7b76ec11 MP	241	static void stripe_map_range_sector(struct stripe_c *sc, sector_t sector,
	242	uint32_t target_stripe, sector_t *result)
	243	{
	244	uint32_t stripe;
	245
	246	stripe_map_sector(sc, sector, &stripe, result);
	247	if (stripe == target_stripe)
	248	return;
eb850de6 MS	249
	250	/* round down */
	251	sector = *result;
33d07c0d MP	252	if (sc->chunk_size_shift < 0)
	253	*result -= sector_div(sector, sc->chunk_size);
	254	else
	255	*result = sector & ~(sector_t)(sc->chunk_size - 1);
eb850de6	256
7b76ec11	257	if (target_stripe < stripe)
eb850de6	258	result += sc->chunk_size; / next chunk */
7b76ec11 MP	259	}
7b76ec11 MP	260
45e621d4 MS	261	static int stripe_map_range(struct stripe_c sc, struct bio bio,
45e621d4 MS	262	uint32_t target_stripe)
7b76ec11 MP	263	{
	264	sector_t begin, end;
	265
4f024f37 KO	266	stripe_map_range_sector(sc, bio->bi_iter.bi_sector,
4f024f37 KO	267	target_stripe, &begin);
f73a1c7d	268	stripe_map_range_sector(sc, bio_end_sector(bio),
7b76ec11 MP	269	target_stripe, &end);
	270	if (begin < end) {
	271	bio->bi_bdev = sc->stripe[target_stripe].dev->bdev;
4f024f37 KO	272	bio->bi_iter.bi_sector = begin +
	273	sc->stripe[target_stripe].physical_start;
	274	bio->bi_iter.bi_size = to_bytes(end - begin);
7b76ec11 MP	275	return DM_MAPIO_REMAPPED;
	276	} else {
	277	/* The range doesn't map to the target stripe */
4246a0b6	278	bio_endio(bio);
7b76ec11 MP	279	return DM_MAPIO_SUBMITTED;
	280	}
	281	}
	282
7de3ee57	283	static int stripe_map(struct dm_target ti, struct bio bio)
1da177e4	284	{
65988525	285	struct stripe_c *sc = ti->private;
374bf7e7	286	uint32_t stripe;
55a62eef	287	unsigned target_bio_nr;
1da177e4	288
d87f4c14	289	if (bio->bi_rw & REQ_FLUSH) {
55a62eef AK	290	target_bio_nr = dm_bio_get_target_bio_nr(bio);
	291	BUG_ON(target_bio_nr >= sc->stripes);
	292	bio->bi_bdev = sc->stripe[target_bio_nr].dev->bdev;
374bf7e7 MP	293	return DM_MAPIO_REMAPPED;
374bf7e7 MP	294	}
45e621d4 MS	295	if (unlikely(bio->bi_rw & REQ_DISCARD) \|\|
45e621d4 MS	296	unlikely(bio->bi_rw & REQ_WRITE_SAME)) {
55a62eef AK	297	target_bio_nr = dm_bio_get_target_bio_nr(bio);
	298	BUG_ON(target_bio_nr >= sc->stripes);
	299	return stripe_map_range(sc, bio, target_bio_nr);
7b76ec11	300	}
374bf7e7	301
4f024f37 KO	302	stripe_map_sector(sc, bio->bi_iter.bi_sector,
4f024f37 KO	303	&stripe, &bio->bi_iter.bi_sector);
1da177e4	304
4f024f37	305	bio->bi_iter.bi_sector += sc->stripe[stripe].physical_start;
1da177e4	306	bio->bi_bdev = sc->stripe[stripe].dev->bdev;
65988525	307
d2a7ad29	308	return DM_MAPIO_REMAPPED;
1da177e4 LT	309	}
1da177e4 LT	310
4f7f5c67 BW	311	/*
	312	* Stripe status:
	313	*
	314	* INFO
	315	* #stripes [stripe_name <stripe_name>] [group word count]
	316	* [error count 'A\|D' <error count 'A\|D'>]
	317	*
	318	* TABLE
	319	* #stripes [stripe chunk size]
	320	* [stripe_name physical_start <stripe_name physical_start>]
	321	*
	322	*/
	323
fd7c092e MP	324	static void stripe_status(struct dm_target *ti, status_type_t type,
fd7c092e MP	325	unsigned status_flags, char *result, unsigned maxlen)
1da177e4 LT	326	{
1da177e4 LT	327	struct stripe_c sc = (struct stripe_c ) ti->private;
4f7f5c67	328	char buffer[sc->stripes + 1];
1da177e4 LT	329	unsigned int sz = 0;
	330	unsigned int i;
	331
	332	switch (type) {
	333	case STATUSTYPE_INFO:
4f7f5c67 BW	334	DMEMIT("%d ", sc->stripes);
	335	for (i = 0; i < sc->stripes; i++) {
	336	DMEMIT("%s ", sc->stripe[i].dev->name);
	337	buffer[i] = atomic_read(&(sc->stripe[i].error_count)) ?
	338	'D' : 'A';
	339	}
	340	buffer[i] = '\0';
	341	DMEMIT("1 %s", buffer);
1da177e4 LT	342	break;
	343
	344	case STATUSTYPE_TABLE:
4ee218cd	345	DMEMIT("%d %llu", sc->stripes,
eb850de6	346	(unsigned long long)sc->chunk_size);
1da177e4	347	for (i = 0; i < sc->stripes; i++)
4ee218cd AM	348	DMEMIT(" %s %llu", sc->stripe[i].dev->name,
4ee218cd AM	349	(unsigned long long)sc->stripe[i].physical_start);
1da177e4 LT	350	break;
1da177e4 LT	351	}
1da177e4 LT	352	}
1da177e4 LT	353
7de3ee57	354	static int stripe_end_io(struct dm_target ti, struct bio bio, int error)
a25eb944 BW	355	{
	356	unsigned i;
	357	char major_minor[16];
	358	struct stripe_c *sc = ti->private;
	359
	360	if (!error)
	361	return 0; /* I/O complete */
	362
7b6d91da	363	if ((error == -EWOULDBLOCK) && (bio->bi_rw & REQ_RAHEAD))
a25eb944 BW	364	return error;
	365
	366	if (error == -EOPNOTSUPP)
	367	return error;
	368
	369	memset(major_minor, 0, sizeof(major_minor));
	370	sprintf(major_minor, "%d:%d",
f331c029 TH	371	MAJOR(disk_devt(bio->bi_bdev->bd_disk)),
f331c029 TH	372	MINOR(disk_devt(bio->bi_bdev->bd_disk)));
a25eb944 BW	373
	374	/*
	375	* Test to see which stripe drive triggered the event
	376	* and increment error count for all stripes on that device.
	377	* If the error count for a given device exceeds the threshold
	378	* value we will no longer trigger any further events.
	379	*/
	380	for (i = 0; i < sc->stripes; i++)
	381	if (!strcmp(sc->stripe[i].dev->name, major_minor)) {
	382	atomic_inc(&(sc->stripe[i].error_count));
	383	if (atomic_read(&(sc->stripe[i].error_count)) <
	384	DM_IO_ERROR_THRESHOLD)
f521f074	385	schedule_work(&sc->trigger_event);
a25eb944 BW	386	}
	387
	388	return error;
	389	}
	390
af4874e0 MS	391	static int stripe_iterate_devices(struct dm_target *ti,
	392	iterate_devices_callout_fn fn, void *data)
	393	{
	394	struct stripe_c *sc = ti->private;
	395	int ret = 0;
	396	unsigned i = 0;
	397
5dea271b	398	do {
af4874e0	399	ret = fn(ti, sc->stripe[i].dev,
5dea271b MS	400	sc->stripe[i].physical_start,
	401	sc->stripe_width, data);
	402	} while (!ret && ++i < sc->stripes);
af4874e0 MS	403
	404	return ret;
	405	}
	406
40bea431 MS	407	static void stripe_io_hints(struct dm_target *ti,
	408	struct queue_limits *limits)
	409	{
	410	struct stripe_c *sc = ti->private;
eb850de6	411	unsigned chunk_size = sc->chunk_size << SECTOR_SHIFT;
40bea431 MS	412
40bea431 MS	413	blk_limits_io_min(limits, chunk_size);
3c5820c7	414	blk_limits_io_opt(limits, chunk_size * sc->stripes);
40bea431 MS	415	}
40bea431 MS	416
1da177e4 LT	417	static struct target_type stripe_target = {
1da177e4 LT	418	.name = "striped",
fd7c092e	419	.version = {1, 5, 1},
1da177e4 LT	420	.module = THIS_MODULE,
	421	.ctr = stripe_ctr,
	422	.dtr = stripe_dtr,
	423	.map = stripe_map,
a25eb944	424	.end_io = stripe_end_io,
1da177e4	425	.status = stripe_status,
af4874e0	426	.iterate_devices = stripe_iterate_devices,
40bea431	427	.io_hints = stripe_io_hints,
1da177e4 LT	428	};
	429
	430	int __init dm_stripe_init(void)
	431	{
	432	int r;
	433
	434	r = dm_register_target(&stripe_target);
e223e1de	435	if (r < 0)
72d94861	436	DMWARN("target registration failed");
1da177e4 LT	437
	438	return r;
	439	}
	440
	441	void dm_stripe_exit(void)
	442	{
10d3bd09	443	dm_unregister_target(&stripe_target);
1da177e4	444	}