Release 4.12 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/dax.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);
}

Contributors
Person
Tokens
Prop
Commits
CommitProp
Brian Wood
34
97.14%
1
50.00%
Tejun Heo
1
2.86%
1
50.00%
Total
35
100.00%
2
100.00%



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);
}

Contributors
Person
Tokens
Prop
Commits
CommitProp
Alan Cox
62
96.88%
1
33.33%
Mikulas Patocka
1
1.56%
1
33.33%
Joe Thornber
1
1.56%
1
33.33%
Total
64
100.00%
3
100.00%

/*
 * 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;
}

Contributors
Person
Tokens
Prop
Commits
CommitProp
Alan Cox
89
80.91%
1
20.00%
Vivek Goyal
10
9.09%
1
20.00%
Mikulas Patocka
7
6.36%
1
20.00%
Andrew Morton
3
2.73%
1
20.00%
Joe Thornber
1
0.91%
1
20.00%
Total
110
100.00%
5
100.00%

/*
 * 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;
	ti->num_write_zeroes_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;
}

Contributors
Person
Tokens
Prop
Commits
CommitProp
Alan Cox
224
48.48%
1
4.00%
Mikulas Patocka
64
13.85%
6
24.00%
Joe Thornber
41
8.87%
3
12.00%
Mike Snitzer
40
8.66%
4
16.00%
Brian Wood
33
7.14%
1
4.00%
Kevin Corry
15
3.25%
1
4.00%
Jianpeng Ma (马建朋)
13
2.81%
1
4.00%
Alasdair G. Kergon
10
2.16%
2
8.00%
Pavitra Kumar
7
1.52%
1
4.00%
Andrew Morton
6
1.30%
2
8.00%
Christoph Hellwig
6
1.30%
1
4.00%
Nikanth Karthikesan
2
0.43%
1
4.00%
Tejun Heo
1
0.22%
1
4.00%
Total
462
100.00%
25
100.00%



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);
}

Contributors
Person
Tokens
Prop
Commits
CommitProp
Alan Cox
63
88.73%
1
25.00%
Tejun Heo
5
7.04%
2
50.00%
Brian Wood
3
4.23%
1
25.00%
Total
71
100.00%
4
100.00%



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;
}

Contributors
Person
Tokens
Prop
Commits
CommitProp
Mikulas Patocka
136
92.52%
4
80.00%
Mike Snitzer
11
7.48%
1
20.00%
Total
147
100.00%
5
100.00%



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 */
}

Contributors
Person
Tokens
Prop
Commits
CommitProp
Mikulas Patocka
87
86.14%
2
66.67%
Mike Snitzer
14
13.86%
1
33.33%
Total
101
100.00%
3
100.00%



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;
	}
}

Contributors
Person
Tokens
Prop
Commits
CommitProp
Mikulas Patocka
115
93.50%
1
25.00%
Kent Overstreet
7
5.69%
2
50.00%
Mike Snitzer
1
0.81%
1
25.00%
Total
123
100.00%
4
100.00%



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_opf & REQ_PREFLUSH) {
		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_op(bio) == REQ_OP_DISCARD) ||
	    unlikely(bio_op(bio) == REQ_OP_WRITE_ZEROES) ||
	    unlikely(bio_op(bio) == REQ_OP_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;
}

Contributors
Person
Tokens
Prop
Commits
CommitProp
Mikulas Patocka
79
41.80%
4
23.53%
Alan Cox
54
28.57%
1
5.88%
Mike Snitzer
12
6.35%
2
11.76%
Alasdair G. Kergon
11
5.82%
2
11.76%
Michael Christie
11
5.82%
2
11.76%
Christoph Hellwig
10
5.29%
1
5.88%
Kent Overstreet
6
3.17%
1
5.88%
Kevin Corry
2
1.06%
1
5.88%
Tejun Heo
2
1.06%
1
5.88%
Kiyoshi Ueda
1
0.53%
1
5.88%
Jens Axboe
1
0.53%
1
5.88%
Total
189
100.00%
17
100.00%



static long stripe_dax_direct_access(struct dm_target *ti, pgoff_t pgoff,
		long nr_pages, void **kaddr, pfn_t *pfn)
{
	sector_t dev_sector, sector = pgoff * PAGE_SECTORS;
	struct stripe_c *sc = ti->private;
	struct dax_device *dax_dev;
	struct block_device *bdev;
	uint32_t stripe;
	long ret;

	stripe_map_sector(sc, sector, &stripe, &dev_sector);
	dev_sector += sc->stripe[stripe].physical_start;
	dax_dev = sc->stripe[stripe].dev->dax_dev;
	bdev = sc->stripe[stripe].dev->bdev;

	ret = bdev_dax_pgoff(bdev, dev_sector, nr_pages * PAGE_SIZE, &pgoff);
	if (ret)
		return ret;
	return dax_direct_access(dax_dev, pgoff, nr_pages, kaddr, pfn);
}

Contributors
Person
Tokens
Prop
Commits
CommitProp
Toshi Kani
85
57.82%
1
50.00%
Dan J Williams
62
42.18%
1
50.00%
Total
147
100.00%
2
100.00%

/*
 * 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;
	}
}

Contributors
Person
Tokens
Prop
Commits
CommitProp
Alan Cox
93
43.26%
1
9.09%
Brian Wood
85
39.53%
1
9.09%
Andrew Morton
16
7.44%
2
18.18%
Kevin Corry
11
5.12%
1
9.09%
Alasdair G. Kergon
4
1.86%
2
18.18%
Lars Marowsky-Bree
2
0.93%
1
9.09%
Joe Thornber
2
0.93%
1
9.09%
Mike Snitzer
1
0.47%
1
9.09%
Mikulas Patocka
1
0.47%
1
9.09%
Total
215
100.00%
11
100.00%



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_opf & 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;
}

Contributors
Person
Tokens
Prop
Commits
CommitProp
Brian Wood
181
90.05%
1
20.00%
Tejun Heo
14
6.97%
2
40.00%
Christoph Hellwig
5
2.49%
1
20.00%
Jens Axboe
1
0.50%
1
20.00%
Total
201
100.00%
5
100.00%



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;
}

Contributors
Person
Tokens
Prop
Commits
CommitProp
Mike Snitzer
87
100.00%
2
100.00%
Total
87
100.00%
2
100.00%



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);
}

Contributors
Person
Tokens
Prop
Commits
CommitProp
Mike Snitzer
48
92.31%
2
66.67%
Martin K. Petersen
4
7.69%
1
33.33%
Total
52
100.00%
3
100.00%


static struct target_type stripe_target = {
	.name   = "striped",
	.version = {1, 6, 0},
	.features = DM_TARGET_PASSES_INTEGRITY,
	.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,
	.direct_access = stripe_dax_direct_access,
};



int __init dm_stripe_init(void)
{
	int r;

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

	return r;
}

Contributors
Person
Tokens
Prop
Commits
CommitProp
Alan Cox
28
84.85%
1
33.33%
Heinz Mauelshagen
4
12.12%
1
33.33%
Alasdair G. Kergon
1
3.03%
1
33.33%
Total
33
100.00%
3
100.00%



void dm_stripe_exit(void)
{
	dm_unregister_target(&stripe_target);
}
Contributors
Person
Tokens
Prop
Commits
CommitProp
Alan Cox
13
100.00%
1
100.00%
Total
13
100.00%
1
100.00%

Overall Contributors
Person
Tokens
Prop
Commits
CommitProp
Alan Cox
714
32.19%
1
1.56%
Mikulas Patocka
502
22.63%
13
20.31%
Brian Wood
360
16.23%
2
3.12%
Mike Snitzer
229
10.32%
9
14.06%
Toshi Kani
91
4.10%
1
1.56%
Dan J Williams
66
2.98%
1
1.56%
Joe Thornber
45
2.03%
3
4.69%
Andrew Morton
35
1.58%
5
7.81%
Alasdair G. Kergon
31
1.40%
6
9.38%
Kevin Corry
28
1.26%
3
4.69%
Tejun Heo
24
1.08%
4
6.25%
Christoph Hellwig
21
0.95%
2
3.12%
Jianpeng Ma (马建朋)
13
0.59%
1
1.56%
Kent Overstreet
13
0.59%
2
3.12%
Michael Christie
11
0.50%
2
3.12%
Vivek Goyal
10
0.45%
1
1.56%
Pavitra Kumar
7
0.32%
1
1.56%
Heinz Mauelshagen
4
0.18%
1
1.56%
Martin K. Petersen
4
0.18%
1
1.56%
Vignesh Babu
3
0.14%
1
1.56%
Nikanth Karthikesan
2
0.09%
1
1.56%
Jens Axboe
2
0.09%
1
1.56%
Lars Marowsky-Bree
2
0.09%
1
1.56%
Kiyoshi Ueda
1
0.05%
1
1.56%
Total
2218
100.00%
64
100.00%
Directory: drivers/md

Information contained on this website is for historical information purposes only and does not indicate or represent copyright ownership.