1211 lines
24 KiB
C
1211 lines
24 KiB
C
/*
|
|
* Copyright (C) 2001, 2002 Sistina Software (UK) Limited.
|
|
* Copyright (C) 2004 Red Hat, Inc. All rights reserved.
|
|
*
|
|
* This file is released under the GPL.
|
|
*/
|
|
|
|
#include "dm.h"
|
|
#include "dm-bio-list.h"
|
|
|
|
#include <linux/init.h>
|
|
#include <linux/module.h>
|
|
#include <linux/moduleparam.h>
|
|
#include <linux/blkpg.h>
|
|
#include <linux/bio.h>
|
|
#include <linux/buffer_head.h>
|
|
#include <linux/mempool.h>
|
|
#include <linux/slab.h>
|
|
#include <linux/idr.h>
|
|
|
|
static const char *_name = DM_NAME;
|
|
|
|
static unsigned int major = 0;
|
|
static unsigned int _major = 0;
|
|
|
|
/*
|
|
* One of these is allocated per bio.
|
|
*/
|
|
struct dm_io {
|
|
struct mapped_device *md;
|
|
int error;
|
|
struct bio *bio;
|
|
atomic_t io_count;
|
|
};
|
|
|
|
/*
|
|
* One of these is allocated per target within a bio. Hopefully
|
|
* this will be simplified out one day.
|
|
*/
|
|
struct target_io {
|
|
struct dm_io *io;
|
|
struct dm_target *ti;
|
|
union map_info info;
|
|
};
|
|
|
|
union map_info *dm_get_mapinfo(struct bio *bio)
|
|
{
|
|
if (bio && bio->bi_private)
|
|
return &((struct target_io *)bio->bi_private)->info;
|
|
return NULL;
|
|
}
|
|
|
|
/*
|
|
* Bits for the md->flags field.
|
|
*/
|
|
#define DMF_BLOCK_IO 0
|
|
#define DMF_SUSPENDED 1
|
|
#define DMF_FS_LOCKED 2
|
|
|
|
struct mapped_device {
|
|
struct rw_semaphore lock;
|
|
rwlock_t map_lock;
|
|
atomic_t holders;
|
|
|
|
unsigned long flags;
|
|
|
|
request_queue_t *queue;
|
|
struct gendisk *disk;
|
|
|
|
void *interface_ptr;
|
|
|
|
/*
|
|
* A list of ios that arrived while we were suspended.
|
|
*/
|
|
atomic_t pending;
|
|
wait_queue_head_t wait;
|
|
struct bio_list deferred;
|
|
|
|
/*
|
|
* The current mapping.
|
|
*/
|
|
struct dm_table *map;
|
|
|
|
/*
|
|
* io objects are allocated from here.
|
|
*/
|
|
mempool_t *io_pool;
|
|
mempool_t *tio_pool;
|
|
|
|
/*
|
|
* Event handling.
|
|
*/
|
|
atomic_t event_nr;
|
|
wait_queue_head_t eventq;
|
|
|
|
/*
|
|
* freeze/thaw support require holding onto a super block
|
|
*/
|
|
struct super_block *frozen_sb;
|
|
struct block_device *frozen_bdev;
|
|
};
|
|
|
|
#define MIN_IOS 256
|
|
static kmem_cache_t *_io_cache;
|
|
static kmem_cache_t *_tio_cache;
|
|
|
|
static struct bio_set *dm_set;
|
|
|
|
static int __init local_init(void)
|
|
{
|
|
int r;
|
|
|
|
dm_set = bioset_create(16, 16, 4);
|
|
if (!dm_set)
|
|
return -ENOMEM;
|
|
|
|
/* allocate a slab for the dm_ios */
|
|
_io_cache = kmem_cache_create("dm_io",
|
|
sizeof(struct dm_io), 0, 0, NULL, NULL);
|
|
if (!_io_cache)
|
|
return -ENOMEM;
|
|
|
|
/* allocate a slab for the target ios */
|
|
_tio_cache = kmem_cache_create("dm_tio", sizeof(struct target_io),
|
|
0, 0, NULL, NULL);
|
|
if (!_tio_cache) {
|
|
kmem_cache_destroy(_io_cache);
|
|
return -ENOMEM;
|
|
}
|
|
|
|
_major = major;
|
|
r = register_blkdev(_major, _name);
|
|
if (r < 0) {
|
|
kmem_cache_destroy(_tio_cache);
|
|
kmem_cache_destroy(_io_cache);
|
|
return r;
|
|
}
|
|
|
|
if (!_major)
|
|
_major = r;
|
|
|
|
return 0;
|
|
}
|
|
|
|
static void local_exit(void)
|
|
{
|
|
kmem_cache_destroy(_tio_cache);
|
|
kmem_cache_destroy(_io_cache);
|
|
|
|
bioset_free(dm_set);
|
|
|
|
if (unregister_blkdev(_major, _name) < 0)
|
|
DMERR("devfs_unregister_blkdev failed");
|
|
|
|
_major = 0;
|
|
|
|
DMINFO("cleaned up");
|
|
}
|
|
|
|
int (*_inits[])(void) __initdata = {
|
|
local_init,
|
|
dm_target_init,
|
|
dm_linear_init,
|
|
dm_stripe_init,
|
|
dm_interface_init,
|
|
};
|
|
|
|
void (*_exits[])(void) = {
|
|
local_exit,
|
|
dm_target_exit,
|
|
dm_linear_exit,
|
|
dm_stripe_exit,
|
|
dm_interface_exit,
|
|
};
|
|
|
|
static int __init dm_init(void)
|
|
{
|
|
const int count = ARRAY_SIZE(_inits);
|
|
|
|
int r, i;
|
|
|
|
for (i = 0; i < count; i++) {
|
|
r = _inits[i]();
|
|
if (r)
|
|
goto bad;
|
|
}
|
|
|
|
return 0;
|
|
|
|
bad:
|
|
while (i--)
|
|
_exits[i]();
|
|
|
|
return r;
|
|
}
|
|
|
|
static void __exit dm_exit(void)
|
|
{
|
|
int i = ARRAY_SIZE(_exits);
|
|
|
|
while (i--)
|
|
_exits[i]();
|
|
}
|
|
|
|
/*
|
|
* Block device functions
|
|
*/
|
|
static int dm_blk_open(struct inode *inode, struct file *file)
|
|
{
|
|
struct mapped_device *md;
|
|
|
|
md = inode->i_bdev->bd_disk->private_data;
|
|
dm_get(md);
|
|
return 0;
|
|
}
|
|
|
|
static int dm_blk_close(struct inode *inode, struct file *file)
|
|
{
|
|
struct mapped_device *md;
|
|
|
|
md = inode->i_bdev->bd_disk->private_data;
|
|
dm_put(md);
|
|
return 0;
|
|
}
|
|
|
|
static inline struct dm_io *alloc_io(struct mapped_device *md)
|
|
{
|
|
return mempool_alloc(md->io_pool, GFP_NOIO);
|
|
}
|
|
|
|
static inline void free_io(struct mapped_device *md, struct dm_io *io)
|
|
{
|
|
mempool_free(io, md->io_pool);
|
|
}
|
|
|
|
static inline struct target_io *alloc_tio(struct mapped_device *md)
|
|
{
|
|
return mempool_alloc(md->tio_pool, GFP_NOIO);
|
|
}
|
|
|
|
static inline void free_tio(struct mapped_device *md, struct target_io *tio)
|
|
{
|
|
mempool_free(tio, md->tio_pool);
|
|
}
|
|
|
|
/*
|
|
* Add the bio to the list of deferred io.
|
|
*/
|
|
static int queue_io(struct mapped_device *md, struct bio *bio)
|
|
{
|
|
down_write(&md->lock);
|
|
|
|
if (!test_bit(DMF_BLOCK_IO, &md->flags)) {
|
|
up_write(&md->lock);
|
|
return 1;
|
|
}
|
|
|
|
bio_list_add(&md->deferred, bio);
|
|
|
|
up_write(&md->lock);
|
|
return 0; /* deferred successfully */
|
|
}
|
|
|
|
/*
|
|
* Everyone (including functions in this file), should use this
|
|
* function to access the md->map field, and make sure they call
|
|
* dm_table_put() when finished.
|
|
*/
|
|
struct dm_table *dm_get_table(struct mapped_device *md)
|
|
{
|
|
struct dm_table *t;
|
|
|
|
read_lock(&md->map_lock);
|
|
t = md->map;
|
|
if (t)
|
|
dm_table_get(t);
|
|
read_unlock(&md->map_lock);
|
|
|
|
return t;
|
|
}
|
|
|
|
/*-----------------------------------------------------------------
|
|
* CRUD START:
|
|
* A more elegant soln is in the works that uses the queue
|
|
* merge fn, unfortunately there are a couple of changes to
|
|
* the block layer that I want to make for this. So in the
|
|
* interests of getting something for people to use I give
|
|
* you this clearly demarcated crap.
|
|
*---------------------------------------------------------------*/
|
|
|
|
/*
|
|
* Decrements the number of outstanding ios that a bio has been
|
|
* cloned into, completing the original io if necc.
|
|
*/
|
|
static inline void dec_pending(struct dm_io *io, int error)
|
|
{
|
|
if (error)
|
|
io->error = error;
|
|
|
|
if (atomic_dec_and_test(&io->io_count)) {
|
|
if (atomic_dec_and_test(&io->md->pending))
|
|
/* nudge anyone waiting on suspend queue */
|
|
wake_up(&io->md->wait);
|
|
|
|
bio_endio(io->bio, io->bio->bi_size, io->error);
|
|
free_io(io->md, io);
|
|
}
|
|
}
|
|
|
|
static int clone_endio(struct bio *bio, unsigned int done, int error)
|
|
{
|
|
int r = 0;
|
|
struct target_io *tio = bio->bi_private;
|
|
struct dm_io *io = tio->io;
|
|
dm_endio_fn endio = tio->ti->type->end_io;
|
|
|
|
if (bio->bi_size)
|
|
return 1;
|
|
|
|
if (!bio_flagged(bio, BIO_UPTODATE) && !error)
|
|
error = -EIO;
|
|
|
|
if (endio) {
|
|
r = endio(tio->ti, bio, error, &tio->info);
|
|
if (r < 0)
|
|
error = r;
|
|
|
|
else if (r > 0)
|
|
/* the target wants another shot at the io */
|
|
return 1;
|
|
}
|
|
|
|
free_tio(io->md, tio);
|
|
dec_pending(io, error);
|
|
bio_put(bio);
|
|
return r;
|
|
}
|
|
|
|
static sector_t max_io_len(struct mapped_device *md,
|
|
sector_t sector, struct dm_target *ti)
|
|
{
|
|
sector_t offset = sector - ti->begin;
|
|
sector_t len = ti->len - offset;
|
|
|
|
/*
|
|
* Does the target need to split even further ?
|
|
*/
|
|
if (ti->split_io) {
|
|
sector_t boundary;
|
|
boundary = ((offset + ti->split_io) & ~(ti->split_io - 1))
|
|
- offset;
|
|
if (len > boundary)
|
|
len = boundary;
|
|
}
|
|
|
|
return len;
|
|
}
|
|
|
|
static void __map_bio(struct dm_target *ti, struct bio *clone,
|
|
struct target_io *tio)
|
|
{
|
|
int r;
|
|
|
|
/*
|
|
* Sanity checks.
|
|
*/
|
|
BUG_ON(!clone->bi_size);
|
|
|
|
clone->bi_end_io = clone_endio;
|
|
clone->bi_private = tio;
|
|
|
|
/*
|
|
* Map the clone. If r == 0 we don't need to do
|
|
* anything, the target has assumed ownership of
|
|
* this io.
|
|
*/
|
|
atomic_inc(&tio->io->io_count);
|
|
r = ti->type->map(ti, clone, &tio->info);
|
|
if (r > 0)
|
|
/* the bio has been remapped so dispatch it */
|
|
generic_make_request(clone);
|
|
|
|
else if (r < 0) {
|
|
/* error the io and bail out */
|
|
struct dm_io *io = tio->io;
|
|
free_tio(tio->io->md, tio);
|
|
dec_pending(io, -EIO);
|
|
bio_put(clone);
|
|
}
|
|
}
|
|
|
|
struct clone_info {
|
|
struct mapped_device *md;
|
|
struct dm_table *map;
|
|
struct bio *bio;
|
|
struct dm_io *io;
|
|
sector_t sector;
|
|
sector_t sector_count;
|
|
unsigned short idx;
|
|
};
|
|
|
|
/*
|
|
* Creates a little bio that is just does part of a bvec.
|
|
*/
|
|
static struct bio *split_bvec(struct bio *bio, sector_t sector,
|
|
unsigned short idx, unsigned int offset,
|
|
unsigned int len)
|
|
{
|
|
struct bio *clone;
|
|
struct bio_vec *bv = bio->bi_io_vec + idx;
|
|
|
|
clone = bio_alloc_bioset(GFP_NOIO, 1, dm_set);
|
|
*clone->bi_io_vec = *bv;
|
|
|
|
clone->bi_sector = sector;
|
|
clone->bi_bdev = bio->bi_bdev;
|
|
clone->bi_rw = bio->bi_rw;
|
|
clone->bi_vcnt = 1;
|
|
clone->bi_size = to_bytes(len);
|
|
clone->bi_io_vec->bv_offset = offset;
|
|
clone->bi_io_vec->bv_len = clone->bi_size;
|
|
|
|
return clone;
|
|
}
|
|
|
|
/*
|
|
* Creates a bio that consists of range of complete bvecs.
|
|
*/
|
|
static struct bio *clone_bio(struct bio *bio, sector_t sector,
|
|
unsigned short idx, unsigned short bv_count,
|
|
unsigned int len)
|
|
{
|
|
struct bio *clone;
|
|
|
|
clone = bio_clone(bio, GFP_NOIO);
|
|
clone->bi_sector = sector;
|
|
clone->bi_idx = idx;
|
|
clone->bi_vcnt = idx + bv_count;
|
|
clone->bi_size = to_bytes(len);
|
|
clone->bi_flags &= ~(1 << BIO_SEG_VALID);
|
|
|
|
return clone;
|
|
}
|
|
|
|
static void __clone_and_map(struct clone_info *ci)
|
|
{
|
|
struct bio *clone, *bio = ci->bio;
|
|
struct dm_target *ti = dm_table_find_target(ci->map, ci->sector);
|
|
sector_t len = 0, max = max_io_len(ci->md, ci->sector, ti);
|
|
struct target_io *tio;
|
|
|
|
/*
|
|
* Allocate a target io object.
|
|
*/
|
|
tio = alloc_tio(ci->md);
|
|
tio->io = ci->io;
|
|
tio->ti = ti;
|
|
memset(&tio->info, 0, sizeof(tio->info));
|
|
|
|
if (ci->sector_count <= max) {
|
|
/*
|
|
* Optimise for the simple case where we can do all of
|
|
* the remaining io with a single clone.
|
|
*/
|
|
clone = clone_bio(bio, ci->sector, ci->idx,
|
|
bio->bi_vcnt - ci->idx, ci->sector_count);
|
|
__map_bio(ti, clone, tio);
|
|
ci->sector_count = 0;
|
|
|
|
} else if (to_sector(bio->bi_io_vec[ci->idx].bv_len) <= max) {
|
|
/*
|
|
* There are some bvecs that don't span targets.
|
|
* Do as many of these as possible.
|
|
*/
|
|
int i;
|
|
sector_t remaining = max;
|
|
sector_t bv_len;
|
|
|
|
for (i = ci->idx; remaining && (i < bio->bi_vcnt); i++) {
|
|
bv_len = to_sector(bio->bi_io_vec[i].bv_len);
|
|
|
|
if (bv_len > remaining)
|
|
break;
|
|
|
|
remaining -= bv_len;
|
|
len += bv_len;
|
|
}
|
|
|
|
clone = clone_bio(bio, ci->sector, ci->idx, i - ci->idx, len);
|
|
__map_bio(ti, clone, tio);
|
|
|
|
ci->sector += len;
|
|
ci->sector_count -= len;
|
|
ci->idx = i;
|
|
|
|
} else {
|
|
/*
|
|
* Create two copy bios to deal with io that has
|
|
* been split across a target.
|
|
*/
|
|
struct bio_vec *bv = bio->bi_io_vec + ci->idx;
|
|
|
|
clone = split_bvec(bio, ci->sector, ci->idx,
|
|
bv->bv_offset, max);
|
|
__map_bio(ti, clone, tio);
|
|
|
|
ci->sector += max;
|
|
ci->sector_count -= max;
|
|
ti = dm_table_find_target(ci->map, ci->sector);
|
|
|
|
len = to_sector(bv->bv_len) - max;
|
|
clone = split_bvec(bio, ci->sector, ci->idx,
|
|
bv->bv_offset + to_bytes(max), len);
|
|
tio = alloc_tio(ci->md);
|
|
tio->io = ci->io;
|
|
tio->ti = ti;
|
|
memset(&tio->info, 0, sizeof(tio->info));
|
|
__map_bio(ti, clone, tio);
|
|
|
|
ci->sector += len;
|
|
ci->sector_count -= len;
|
|
ci->idx++;
|
|
}
|
|
}
|
|
|
|
/*
|
|
* Split the bio into several clones.
|
|
*/
|
|
static void __split_bio(struct mapped_device *md, struct bio *bio)
|
|
{
|
|
struct clone_info ci;
|
|
|
|
ci.map = dm_get_table(md);
|
|
if (!ci.map) {
|
|
bio_io_error(bio, bio->bi_size);
|
|
return;
|
|
}
|
|
|
|
ci.md = md;
|
|
ci.bio = bio;
|
|
ci.io = alloc_io(md);
|
|
ci.io->error = 0;
|
|
atomic_set(&ci.io->io_count, 1);
|
|
ci.io->bio = bio;
|
|
ci.io->md = md;
|
|
ci.sector = bio->bi_sector;
|
|
ci.sector_count = bio_sectors(bio);
|
|
ci.idx = bio->bi_idx;
|
|
|
|
atomic_inc(&md->pending);
|
|
while (ci.sector_count)
|
|
__clone_and_map(&ci);
|
|
|
|
/* drop the extra reference count */
|
|
dec_pending(ci.io, 0);
|
|
dm_table_put(ci.map);
|
|
}
|
|
/*-----------------------------------------------------------------
|
|
* CRUD END
|
|
*---------------------------------------------------------------*/
|
|
|
|
/*
|
|
* The request function that just remaps the bio built up by
|
|
* dm_merge_bvec.
|
|
*/
|
|
static int dm_request(request_queue_t *q, struct bio *bio)
|
|
{
|
|
int r;
|
|
struct mapped_device *md = q->queuedata;
|
|
|
|
down_read(&md->lock);
|
|
|
|
/*
|
|
* If we're suspended we have to queue
|
|
* this io for later.
|
|
*/
|
|
while (test_bit(DMF_BLOCK_IO, &md->flags)) {
|
|
up_read(&md->lock);
|
|
|
|
if (bio_rw(bio) == READA) {
|
|
bio_io_error(bio, bio->bi_size);
|
|
return 0;
|
|
}
|
|
|
|
r = queue_io(md, bio);
|
|
if (r < 0) {
|
|
bio_io_error(bio, bio->bi_size);
|
|
return 0;
|
|
|
|
} else if (r == 0)
|
|
return 0; /* deferred successfully */
|
|
|
|
/*
|
|
* We're in a while loop, because someone could suspend
|
|
* before we get to the following read lock.
|
|
*/
|
|
down_read(&md->lock);
|
|
}
|
|
|
|
__split_bio(md, bio);
|
|
up_read(&md->lock);
|
|
return 0;
|
|
}
|
|
|
|
static int dm_flush_all(request_queue_t *q, struct gendisk *disk,
|
|
sector_t *error_sector)
|
|
{
|
|
struct mapped_device *md = q->queuedata;
|
|
struct dm_table *map = dm_get_table(md);
|
|
int ret = -ENXIO;
|
|
|
|
if (map) {
|
|
ret = dm_table_flush_all(md->map);
|
|
dm_table_put(map);
|
|
}
|
|
|
|
return ret;
|
|
}
|
|
|
|
static void dm_unplug_all(request_queue_t *q)
|
|
{
|
|
struct mapped_device *md = q->queuedata;
|
|
struct dm_table *map = dm_get_table(md);
|
|
|
|
if (map) {
|
|
dm_table_unplug_all(map);
|
|
dm_table_put(map);
|
|
}
|
|
}
|
|
|
|
static int dm_any_congested(void *congested_data, int bdi_bits)
|
|
{
|
|
int r;
|
|
struct mapped_device *md = (struct mapped_device *) congested_data;
|
|
struct dm_table *map = dm_get_table(md);
|
|
|
|
if (!map || test_bit(DMF_BLOCK_IO, &md->flags))
|
|
r = bdi_bits;
|
|
else
|
|
r = dm_table_any_congested(map, bdi_bits);
|
|
|
|
dm_table_put(map);
|
|
return r;
|
|
}
|
|
|
|
/*-----------------------------------------------------------------
|
|
* An IDR is used to keep track of allocated minor numbers.
|
|
*---------------------------------------------------------------*/
|
|
static DECLARE_MUTEX(_minor_lock);
|
|
static DEFINE_IDR(_minor_idr);
|
|
|
|
static void free_minor(unsigned int minor)
|
|
{
|
|
down(&_minor_lock);
|
|
idr_remove(&_minor_idr, minor);
|
|
up(&_minor_lock);
|
|
}
|
|
|
|
/*
|
|
* See if the device with a specific minor # is free.
|
|
*/
|
|
static int specific_minor(struct mapped_device *md, unsigned int minor)
|
|
{
|
|
int r, m;
|
|
|
|
if (minor >= (1 << MINORBITS))
|
|
return -EINVAL;
|
|
|
|
down(&_minor_lock);
|
|
|
|
if (idr_find(&_minor_idr, minor)) {
|
|
r = -EBUSY;
|
|
goto out;
|
|
}
|
|
|
|
r = idr_pre_get(&_minor_idr, GFP_KERNEL);
|
|
if (!r) {
|
|
r = -ENOMEM;
|
|
goto out;
|
|
}
|
|
|
|
r = idr_get_new_above(&_minor_idr, md, minor, &m);
|
|
if (r) {
|
|
goto out;
|
|
}
|
|
|
|
if (m != minor) {
|
|
idr_remove(&_minor_idr, m);
|
|
r = -EBUSY;
|
|
goto out;
|
|
}
|
|
|
|
out:
|
|
up(&_minor_lock);
|
|
return r;
|
|
}
|
|
|
|
static int next_free_minor(struct mapped_device *md, unsigned int *minor)
|
|
{
|
|
int r;
|
|
unsigned int m;
|
|
|
|
down(&_minor_lock);
|
|
|
|
r = idr_pre_get(&_minor_idr, GFP_KERNEL);
|
|
if (!r) {
|
|
r = -ENOMEM;
|
|
goto out;
|
|
}
|
|
|
|
r = idr_get_new(&_minor_idr, md, &m);
|
|
if (r) {
|
|
goto out;
|
|
}
|
|
|
|
if (m >= (1 << MINORBITS)) {
|
|
idr_remove(&_minor_idr, m);
|
|
r = -ENOSPC;
|
|
goto out;
|
|
}
|
|
|
|
*minor = m;
|
|
|
|
out:
|
|
up(&_minor_lock);
|
|
return r;
|
|
}
|
|
|
|
static struct block_device_operations dm_blk_dops;
|
|
|
|
/*
|
|
* Allocate and initialise a blank device with a given minor.
|
|
*/
|
|
static struct mapped_device *alloc_dev(unsigned int minor, int persistent)
|
|
{
|
|
int r;
|
|
struct mapped_device *md = kmalloc(sizeof(*md), GFP_KERNEL);
|
|
|
|
if (!md) {
|
|
DMWARN("unable to allocate device, out of memory.");
|
|
return NULL;
|
|
}
|
|
|
|
/* get a minor number for the dev */
|
|
r = persistent ? specific_minor(md, minor) : next_free_minor(md, &minor);
|
|
if (r < 0)
|
|
goto bad1;
|
|
|
|
memset(md, 0, sizeof(*md));
|
|
init_rwsem(&md->lock);
|
|
rwlock_init(&md->map_lock);
|
|
atomic_set(&md->holders, 1);
|
|
atomic_set(&md->event_nr, 0);
|
|
|
|
md->queue = blk_alloc_queue(GFP_KERNEL);
|
|
if (!md->queue)
|
|
goto bad1;
|
|
|
|
md->queue->queuedata = md;
|
|
md->queue->backing_dev_info.congested_fn = dm_any_congested;
|
|
md->queue->backing_dev_info.congested_data = md;
|
|
blk_queue_make_request(md->queue, dm_request);
|
|
md->queue->unplug_fn = dm_unplug_all;
|
|
md->queue->issue_flush_fn = dm_flush_all;
|
|
|
|
md->io_pool = mempool_create(MIN_IOS, mempool_alloc_slab,
|
|
mempool_free_slab, _io_cache);
|
|
if (!md->io_pool)
|
|
goto bad2;
|
|
|
|
md->tio_pool = mempool_create(MIN_IOS, mempool_alloc_slab,
|
|
mempool_free_slab, _tio_cache);
|
|
if (!md->tio_pool)
|
|
goto bad3;
|
|
|
|
md->disk = alloc_disk(1);
|
|
if (!md->disk)
|
|
goto bad4;
|
|
|
|
md->disk->major = _major;
|
|
md->disk->first_minor = minor;
|
|
md->disk->fops = &dm_blk_dops;
|
|
md->disk->queue = md->queue;
|
|
md->disk->private_data = md;
|
|
sprintf(md->disk->disk_name, "dm-%d", minor);
|
|
add_disk(md->disk);
|
|
|
|
atomic_set(&md->pending, 0);
|
|
init_waitqueue_head(&md->wait);
|
|
init_waitqueue_head(&md->eventq);
|
|
|
|
return md;
|
|
|
|
bad4:
|
|
mempool_destroy(md->tio_pool);
|
|
bad3:
|
|
mempool_destroy(md->io_pool);
|
|
bad2:
|
|
blk_put_queue(md->queue);
|
|
free_minor(minor);
|
|
bad1:
|
|
kfree(md);
|
|
return NULL;
|
|
}
|
|
|
|
static void free_dev(struct mapped_device *md)
|
|
{
|
|
free_minor(md->disk->first_minor);
|
|
mempool_destroy(md->tio_pool);
|
|
mempool_destroy(md->io_pool);
|
|
del_gendisk(md->disk);
|
|
put_disk(md->disk);
|
|
blk_put_queue(md->queue);
|
|
kfree(md);
|
|
}
|
|
|
|
/*
|
|
* Bind a table to the device.
|
|
*/
|
|
static void event_callback(void *context)
|
|
{
|
|
struct mapped_device *md = (struct mapped_device *) context;
|
|
|
|
atomic_inc(&md->event_nr);
|
|
wake_up(&md->eventq);
|
|
}
|
|
|
|
static void __set_size(struct gendisk *disk, sector_t size)
|
|
{
|
|
struct block_device *bdev;
|
|
|
|
set_capacity(disk, size);
|
|
bdev = bdget_disk(disk, 0);
|
|
if (bdev) {
|
|
down(&bdev->bd_inode->i_sem);
|
|
i_size_write(bdev->bd_inode, (loff_t)size << SECTOR_SHIFT);
|
|
up(&bdev->bd_inode->i_sem);
|
|
bdput(bdev);
|
|
}
|
|
}
|
|
|
|
static int __bind(struct mapped_device *md, struct dm_table *t)
|
|
{
|
|
request_queue_t *q = md->queue;
|
|
sector_t size;
|
|
|
|
size = dm_table_get_size(t);
|
|
__set_size(md->disk, size);
|
|
if (size == 0)
|
|
return 0;
|
|
|
|
write_lock(&md->map_lock);
|
|
md->map = t;
|
|
write_unlock(&md->map_lock);
|
|
|
|
dm_table_get(t);
|
|
dm_table_event_callback(md->map, event_callback, md);
|
|
dm_table_set_restrictions(t, q);
|
|
return 0;
|
|
}
|
|
|
|
static void __unbind(struct mapped_device *md)
|
|
{
|
|
struct dm_table *map = md->map;
|
|
|
|
if (!map)
|
|
return;
|
|
|
|
dm_table_event_callback(map, NULL, NULL);
|
|
write_lock(&md->map_lock);
|
|
md->map = NULL;
|
|
write_unlock(&md->map_lock);
|
|
dm_table_put(map);
|
|
}
|
|
|
|
/*
|
|
* Constructor for a new device.
|
|
*/
|
|
static int create_aux(unsigned int minor, int persistent,
|
|
struct mapped_device **result)
|
|
{
|
|
struct mapped_device *md;
|
|
|
|
md = alloc_dev(minor, persistent);
|
|
if (!md)
|
|
return -ENXIO;
|
|
|
|
*result = md;
|
|
return 0;
|
|
}
|
|
|
|
int dm_create(struct mapped_device **result)
|
|
{
|
|
return create_aux(0, 0, result);
|
|
}
|
|
|
|
int dm_create_with_minor(unsigned int minor, struct mapped_device **result)
|
|
{
|
|
return create_aux(minor, 1, result);
|
|
}
|
|
|
|
void *dm_get_mdptr(dev_t dev)
|
|
{
|
|
struct mapped_device *md;
|
|
void *mdptr = NULL;
|
|
unsigned minor = MINOR(dev);
|
|
|
|
if (MAJOR(dev) != _major || minor >= (1 << MINORBITS))
|
|
return NULL;
|
|
|
|
down(&_minor_lock);
|
|
|
|
md = idr_find(&_minor_idr, minor);
|
|
|
|
if (md && (dm_disk(md)->first_minor == minor))
|
|
mdptr = md->interface_ptr;
|
|
|
|
up(&_minor_lock);
|
|
|
|
return mdptr;
|
|
}
|
|
|
|
void dm_set_mdptr(struct mapped_device *md, void *ptr)
|
|
{
|
|
md->interface_ptr = ptr;
|
|
}
|
|
|
|
void dm_get(struct mapped_device *md)
|
|
{
|
|
atomic_inc(&md->holders);
|
|
}
|
|
|
|
void dm_put(struct mapped_device *md)
|
|
{
|
|
struct dm_table *map = dm_get_table(md);
|
|
|
|
if (atomic_dec_and_test(&md->holders)) {
|
|
if (!test_bit(DMF_SUSPENDED, &md->flags) && map) {
|
|
dm_table_presuspend_targets(map);
|
|
dm_table_postsuspend_targets(map);
|
|
}
|
|
__unbind(md);
|
|
free_dev(md);
|
|
}
|
|
|
|
dm_table_put(map);
|
|
}
|
|
|
|
/*
|
|
* Process the deferred bios
|
|
*/
|
|
static void __flush_deferred_io(struct mapped_device *md, struct bio *c)
|
|
{
|
|
struct bio *n;
|
|
|
|
while (c) {
|
|
n = c->bi_next;
|
|
c->bi_next = NULL;
|
|
__split_bio(md, c);
|
|
c = n;
|
|
}
|
|
}
|
|
|
|
/*
|
|
* Swap in a new table (destroying old one).
|
|
*/
|
|
int dm_swap_table(struct mapped_device *md, struct dm_table *table)
|
|
{
|
|
int r;
|
|
|
|
down_write(&md->lock);
|
|
|
|
/* device must be suspended */
|
|
if (!test_bit(DMF_SUSPENDED, &md->flags)) {
|
|
up_write(&md->lock);
|
|
return -EPERM;
|
|
}
|
|
|
|
__unbind(md);
|
|
r = __bind(md, table);
|
|
if (r)
|
|
return r;
|
|
|
|
up_write(&md->lock);
|
|
return 0;
|
|
}
|
|
|
|
/*
|
|
* Functions to lock and unlock any filesystem running on the
|
|
* device.
|
|
*/
|
|
static int __lock_fs(struct mapped_device *md)
|
|
{
|
|
int error = -ENOMEM;
|
|
|
|
if (test_and_set_bit(DMF_FS_LOCKED, &md->flags))
|
|
return 0;
|
|
|
|
md->frozen_bdev = bdget_disk(md->disk, 0);
|
|
if (!md->frozen_bdev) {
|
|
DMWARN("bdget failed in __lock_fs");
|
|
goto out;
|
|
}
|
|
|
|
WARN_ON(md->frozen_sb);
|
|
|
|
md->frozen_sb = freeze_bdev(md->frozen_bdev);
|
|
if (IS_ERR(md->frozen_sb)) {
|
|
error = PTR_ERR(md->frozen_sb);
|
|
goto out_bdput;
|
|
}
|
|
|
|
/* don't bdput right now, we don't want the bdev
|
|
* to go away while it is locked. We'll bdput
|
|
* in __unlock_fs
|
|
*/
|
|
return 0;
|
|
|
|
out_bdput:
|
|
bdput(md->frozen_bdev);
|
|
md->frozen_sb = NULL;
|
|
md->frozen_bdev = NULL;
|
|
out:
|
|
clear_bit(DMF_FS_LOCKED, &md->flags);
|
|
return error;
|
|
}
|
|
|
|
static void __unlock_fs(struct mapped_device *md)
|
|
{
|
|
if (!test_and_clear_bit(DMF_FS_LOCKED, &md->flags))
|
|
return;
|
|
|
|
thaw_bdev(md->frozen_bdev, md->frozen_sb);
|
|
bdput(md->frozen_bdev);
|
|
|
|
md->frozen_sb = NULL;
|
|
md->frozen_bdev = NULL;
|
|
}
|
|
|
|
/*
|
|
* We need to be able to change a mapping table under a mounted
|
|
* filesystem. For example we might want to move some data in
|
|
* the background. Before the table can be swapped with
|
|
* dm_bind_table, dm_suspend must be called to flush any in
|
|
* flight bios and ensure that any further io gets deferred.
|
|
*/
|
|
int dm_suspend(struct mapped_device *md)
|
|
{
|
|
struct dm_table *map;
|
|
DECLARE_WAITQUEUE(wait, current);
|
|
int error = -EINVAL;
|
|
|
|
/* Flush I/O to the device. */
|
|
down_read(&md->lock);
|
|
if (test_bit(DMF_BLOCK_IO, &md->flags))
|
|
goto out_read_unlock;
|
|
|
|
error = __lock_fs(md);
|
|
if (error)
|
|
goto out_read_unlock;
|
|
|
|
map = dm_get_table(md);
|
|
if (map)
|
|
dm_table_presuspend_targets(map);
|
|
|
|
up_read(&md->lock);
|
|
|
|
/*
|
|
* First we set the BLOCK_IO flag so no more ios will be mapped.
|
|
*
|
|
* If the flag is already set we know another thread is trying to
|
|
* suspend as well, so we leave the fs locked for this thread.
|
|
*/
|
|
error = -EINVAL;
|
|
down_write(&md->lock);
|
|
if (test_and_set_bit(DMF_BLOCK_IO, &md->flags)) {
|
|
if (map)
|
|
dm_table_put(map);
|
|
goto out_write_unlock;
|
|
}
|
|
|
|
add_wait_queue(&md->wait, &wait);
|
|
up_write(&md->lock);
|
|
|
|
/* unplug */
|
|
if (map) {
|
|
dm_table_unplug_all(map);
|
|
dm_table_put(map);
|
|
}
|
|
|
|
/*
|
|
* Then we wait for the already mapped ios to
|
|
* complete.
|
|
*/
|
|
while (1) {
|
|
set_current_state(TASK_INTERRUPTIBLE);
|
|
|
|
if (!atomic_read(&md->pending) || signal_pending(current))
|
|
break;
|
|
|
|
io_schedule();
|
|
}
|
|
set_current_state(TASK_RUNNING);
|
|
|
|
down_write(&md->lock);
|
|
remove_wait_queue(&md->wait, &wait);
|
|
|
|
/* were we interrupted ? */
|
|
error = -EINTR;
|
|
if (atomic_read(&md->pending))
|
|
goto out_unfreeze;
|
|
|
|
set_bit(DMF_SUSPENDED, &md->flags);
|
|
|
|
map = dm_get_table(md);
|
|
if (map)
|
|
dm_table_postsuspend_targets(map);
|
|
dm_table_put(map);
|
|
up_write(&md->lock);
|
|
|
|
return 0;
|
|
|
|
out_unfreeze:
|
|
/* FIXME Undo dm_table_presuspend_targets */
|
|
__unlock_fs(md);
|
|
clear_bit(DMF_BLOCK_IO, &md->flags);
|
|
out_write_unlock:
|
|
up_write(&md->lock);
|
|
return error;
|
|
|
|
out_read_unlock:
|
|
up_read(&md->lock);
|
|
return error;
|
|
}
|
|
|
|
int dm_resume(struct mapped_device *md)
|
|
{
|
|
struct bio *def;
|
|
struct dm_table *map = dm_get_table(md);
|
|
|
|
down_write(&md->lock);
|
|
if (!map ||
|
|
!test_bit(DMF_SUSPENDED, &md->flags) ||
|
|
!dm_table_get_size(map)) {
|
|
up_write(&md->lock);
|
|
dm_table_put(map);
|
|
return -EINVAL;
|
|
}
|
|
|
|
dm_table_resume_targets(map);
|
|
clear_bit(DMF_SUSPENDED, &md->flags);
|
|
clear_bit(DMF_BLOCK_IO, &md->flags);
|
|
|
|
def = bio_list_get(&md->deferred);
|
|
__flush_deferred_io(md, def);
|
|
up_write(&md->lock);
|
|
__unlock_fs(md);
|
|
dm_table_unplug_all(map);
|
|
dm_table_put(map);
|
|
|
|
return 0;
|
|
}
|
|
|
|
/*-----------------------------------------------------------------
|
|
* Event notification.
|
|
*---------------------------------------------------------------*/
|
|
uint32_t dm_get_event_nr(struct mapped_device *md)
|
|
{
|
|
return atomic_read(&md->event_nr);
|
|
}
|
|
|
|
int dm_wait_event(struct mapped_device *md, int event_nr)
|
|
{
|
|
return wait_event_interruptible(md->eventq,
|
|
(event_nr != atomic_read(&md->event_nr)));
|
|
}
|
|
|
|
/*
|
|
* The gendisk is only valid as long as you have a reference
|
|
* count on 'md'.
|
|
*/
|
|
struct gendisk *dm_disk(struct mapped_device *md)
|
|
{
|
|
return md->disk;
|
|
}
|
|
|
|
int dm_suspended(struct mapped_device *md)
|
|
{
|
|
return test_bit(DMF_SUSPENDED, &md->flags);
|
|
}
|
|
|
|
static struct block_device_operations dm_blk_dops = {
|
|
.open = dm_blk_open,
|
|
.release = dm_blk_close,
|
|
.owner = THIS_MODULE
|
|
};
|
|
|
|
EXPORT_SYMBOL(dm_get_mapinfo);
|
|
|
|
/*
|
|
* module hooks
|
|
*/
|
|
module_init(dm_init);
|
|
module_exit(dm_exit);
|
|
|
|
module_param(major, uint, 0);
|
|
MODULE_PARM_DESC(major, "The major number of the device mapper");
|
|
MODULE_DESCRIPTION(DM_NAME " driver");
|
|
MODULE_AUTHOR("Joe Thornber <dm-devel@redhat.com>");
|
|
MODULE_LICENSE("GPL");
|