![Kevin Corry](/assets/img/avatar_default.png)
Signed-off-by: Kevin Corry <kevcorry@us.ibm.com> Cc: Alasdair G Kergon <agk@redhat.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
242 lines
4.9 KiB
C
242 lines
4.9 KiB
C
/*
|
|
* Copyright (C) 2001-2003 Sistina Software (UK) Limited.
|
|
*
|
|
* This file is released under the GPL.
|
|
*/
|
|
|
|
#include "dm.h"
|
|
|
|
#include <linux/module.h>
|
|
#include <linux/init.h>
|
|
#include <linux/blkdev.h>
|
|
#include <linux/bio.h>
|
|
#include <linux/slab.h>
|
|
|
|
struct stripe {
|
|
struct dm_dev *dev;
|
|
sector_t physical_start;
|
|
};
|
|
|
|
struct stripe_c {
|
|
uint32_t stripes;
|
|
|
|
/* The size of this target / num. stripes */
|
|
sector_t stripe_width;
|
|
|
|
/* stripe chunk size */
|
|
uint32_t chunk_shift;
|
|
sector_t chunk_mask;
|
|
|
|
struct stripe stripe[0];
|
|
};
|
|
|
|
static inline struct stripe_c *alloc_context(unsigned int stripes)
|
|
{
|
|
size_t len;
|
|
|
|
if (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;
|
|
|
|
if (sscanf(argv[1], "%llu", &start) != 1)
|
|
return -EINVAL;
|
|
|
|
if (dm_get_device(ti, argv[0], start, sc->stripe_width,
|
|
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 (2^^n)> [<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;
|
|
char *end;
|
|
int r;
|
|
unsigned int i;
|
|
|
|
if (argc < 2) {
|
|
ti->error = "dm-stripe: Not enough arguments";
|
|
return -EINVAL;
|
|
}
|
|
|
|
stripes = simple_strtoul(argv[0], &end, 10);
|
|
if (*end) {
|
|
ti->error = "dm-stripe: Invalid stripe count";
|
|
return -EINVAL;
|
|
}
|
|
|
|
chunk_size = simple_strtoul(argv[1], &end, 10);
|
|
if (*end) {
|
|
ti->error = "dm-stripe: Invalid chunk_size";
|
|
return -EINVAL;
|
|
}
|
|
|
|
/*
|
|
* chunk_size is a power of two
|
|
*/
|
|
if (!chunk_size || (chunk_size & (chunk_size - 1)) ||
|
|
(chunk_size < (PAGE_SIZE >> SECTOR_SHIFT))) {
|
|
ti->error = "dm-stripe: Invalid chunk size";
|
|
return -EINVAL;
|
|
}
|
|
|
|
if (ti->len & (chunk_size - 1)) {
|
|
ti->error = "dm-stripe: Target length not divisible by "
|
|
"chunk size";
|
|
return -EINVAL;
|
|
}
|
|
|
|
width = ti->len;
|
|
if (sector_div(width, stripes)) {
|
|
ti->error = "dm-stripe: 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 = "dm-stripe: Not enough destinations "
|
|
"specified";
|
|
return -EINVAL;
|
|
}
|
|
|
|
sc = alloc_context(stripes);
|
|
if (!sc) {
|
|
ti->error = "dm-stripe: Memory allocation for striped context "
|
|
"failed";
|
|
return -ENOMEM;
|
|
}
|
|
|
|
sc->stripes = stripes;
|
|
sc->stripe_width = width;
|
|
ti->split_io = chunk_size;
|
|
|
|
sc->chunk_mask = ((sector_t) chunk_size) - 1;
|
|
for (sc->chunk_shift = 0; chunk_size; sc->chunk_shift++)
|
|
chunk_size >>= 1;
|
|
sc->chunk_shift--;
|
|
|
|
/*
|
|
* Get the stripe destinations.
|
|
*/
|
|
for (i = 0; i < stripes; i++) {
|
|
argv += 2;
|
|
|
|
r = get_stripe(ti, sc, i, argv);
|
|
if (r < 0) {
|
|
ti->error = "dm-stripe: Couldn't parse stripe "
|
|
"destination";
|
|
while (i--)
|
|
dm_put_device(ti, sc->stripe[i].dev);
|
|
kfree(sc);
|
|
return r;
|
|
}
|
|
}
|
|
|
|
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);
|
|
|
|
kfree(sc);
|
|
}
|
|
|
|
static int stripe_map(struct dm_target *ti, struct bio *bio,
|
|
union map_info *map_context)
|
|
{
|
|
struct stripe_c *sc = (struct stripe_c *) ti->private;
|
|
|
|
sector_t offset = bio->bi_sector - ti->begin;
|
|
sector_t chunk = offset >> sc->chunk_shift;
|
|
uint32_t stripe = sector_div(chunk, sc->stripes);
|
|
|
|
bio->bi_bdev = sc->stripe[stripe].dev->bdev;
|
|
bio->bi_sector = sc->stripe[stripe].physical_start +
|
|
(chunk << sc->chunk_shift) + (offset & sc->chunk_mask);
|
|
return 1;
|
|
}
|
|
|
|
static int stripe_status(struct dm_target *ti,
|
|
status_type_t type, char *result, unsigned int maxlen)
|
|
{
|
|
struct stripe_c *sc = (struct stripe_c *) ti->private;
|
|
unsigned int sz = 0;
|
|
unsigned int i;
|
|
|
|
switch (type) {
|
|
case STATUSTYPE_INFO:
|
|
result[0] = '\0';
|
|
break;
|
|
|
|
case STATUSTYPE_TABLE:
|
|
DMEMIT("%d %llu", sc->stripes,
|
|
(unsigned long long)sc->chunk_mask + 1);
|
|
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 struct target_type stripe_target = {
|
|
.name = "striped",
|
|
.version= {1, 0, 2},
|
|
.module = THIS_MODULE,
|
|
.ctr = stripe_ctr,
|
|
.dtr = stripe_dtr,
|
|
.map = stripe_map,
|
|
.status = stripe_status,
|
|
};
|
|
|
|
int __init dm_stripe_init(void)
|
|
{
|
|
int r;
|
|
|
|
r = dm_register_target(&stripe_target);
|
|
if (r < 0)
|
|
DMWARN("striped target registration failed");
|
|
|
|
return r;
|
|
}
|
|
|
|
void dm_stripe_exit(void)
|
|
{
|
|
if (dm_unregister_target(&stripe_target))
|
|
DMWARN("striped target unregistration failed");
|
|
|
|
return;
|
|
}
|