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Merge git://git.kernel.org/pub/scm/linux/kernel/git/agk/linux-2.6-dm 

* git://git.kernel.org/pub/scm/linux/kernel/git/agk/linux-2.6-dm: (44 commits)
  dm raid1: report fault status
  dm raid1: handle read failures
  dm raid1: fix EIO after log failure
  dm raid1: handle recovery failures
  dm raid1: handle write failures
  dm snapshot: combine consecutive exceptions in memory
  dm: stripe enhanced status return
  dm: stripe trigger event on failure
  dm log: auto load modules
  dm: move deferred bio flushing to workqueue
  dm crypt: use async crypto
  dm crypt: prepare async callback fn
  dm crypt: add completion for async
  dm crypt: add async request mempool
  dm crypt: extract scatterlist processing
  dm crypt: tidy io ref counting
  dm crypt: introduce crypt_write_io_loop
  dm crypt: abstract crypt_write_done
  dm crypt: store sector mapping in dm_crypt_io
  dm crypt: move queue functions
  ...
This commit is contained in:
Linus Torvalds 2008-02-07 19:30:50 -08:00
parent d7511ec811 af195ac82e
commit a4ffc0a0b2
15 changed files with 1378 additions and 489 deletions
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24
drivers/md/Kconfig
View File

@ -204,7 +204,7 @@ config BLK_DEV_DM
config DM_DEBUG
boolean "Device mapper debugging support"
depends on BLK_DEV_DM && EXPERIMENTAL
depends on BLK_DEV_DM
---help---
Enable this for messages that may help debug device-mapper problems.
@ -212,7 +212,7 @@ config DM_DEBUG
config DM_CRYPT
tristate "Crypt target support"
depends on BLK_DEV_DM && EXPERIMENTAL
depends on BLK_DEV_DM
select CRYPTO
select CRYPTO_CBC
---help---
@ -230,34 +230,34 @@ config DM_CRYPT
If unsure, say N.
config DM_SNAPSHOT
tristate "Snapshot target (EXPERIMENTAL)"
depends on BLK_DEV_DM && EXPERIMENTAL
tristate "Snapshot target"
depends on BLK_DEV_DM
---help---
Allow volume managers to take writable snapshots of a device.
config DM_MIRROR
tristate "Mirror target (EXPERIMENTAL)"
depends on BLK_DEV_DM && EXPERIMENTAL
tristate "Mirror target"
depends on BLK_DEV_DM
---help---
Allow volume managers to mirror logical volumes, also
needed for live data migration tools such as 'pvmove'.
config DM_ZERO
tristate "Zero target (EXPERIMENTAL)"
depends on BLK_DEV_DM && EXPERIMENTAL
tristate "Zero target"
depends on BLK_DEV_DM
---help---
A target that discards writes, and returns all zeroes for
reads. Useful in some recovery situations.
config DM_MULTIPATH
tristate "Multipath target (EXPERIMENTAL)"
depends on BLK_DEV_DM && EXPERIMENTAL
tristate "Multipath target"
depends on BLK_DEV_DM
---help---
Allow volume managers to support multipath hardware.
config DM_MULTIPATH_EMC
tristate "EMC CX/AX multipath support (EXPERIMENTAL)"
depends on DM_MULTIPATH && BLK_DEV_DM && EXPERIMENTAL
tristate "EMC CX/AX multipath support"
depends on DM_MULTIPATH && BLK_DEV_DM
---help---
Multipath support for EMC CX/AX series hardware.

488
drivers/md/dm-crypt.c
View File

@ -1,11 +1,12 @@
/*
* Copyright (C) 2003 Christophe Saout <christophe@saout.de>
* Copyright (C) 2004 Clemens Fruhwirth <clemens@endorphin.org>
* Copyright (C) 2006 Red Hat, Inc. All rights reserved.
* Copyright (C) 2006-2007 Red Hat, Inc. All rights reserved.
*
* This file is released under the GPL.
*/
#include <linux/completion.h>
#include <linux/err.h>
#include <linux/module.h>
#include <linux/init.h>
@ -27,21 +28,11 @@
#define DM_MSG_PREFIX "crypt"
#define MESG_STR(x) x, sizeof(x)
/*
* per bio private data
*/
struct dm_crypt_io {
struct dm_target *target;
struct bio *base_bio;
struct work_struct work;
atomic_t pending;
int error;
};
/*
* context holding the current state of a multi-part conversion
*/
struct convert_context {
struct completion restart;
struct bio *bio_in;
struct bio *bio_out;
unsigned int offset_in;
@ -49,7 +40,27 @@ struct convert_context {
unsigned int idx_in;
unsigned int idx_out;
sector_t sector;
int write;
atomic_t pending;
};
/*
* per bio private data
*/
struct dm_crypt_io {
struct dm_target *target;
struct bio *base_bio;
struct work_struct work;
struct convert_context ctx;
atomic_t pending;
int error;
sector_t sector;
};
struct dm_crypt_request {
struct scatterlist sg_in;
struct scatterlist sg_out;
};
struct crypt_config;
@ -72,10 +83,11 @@ struct crypt_config {
sector_t start;
/*
* pool for per bio private data and
* for encryption buffer pages
* pool for per bio private data, crypto requests and
* encryption requeusts/buffer pages
*/
mempool_t *io_pool;
mempool_t *req_pool;
mempool_t *page_pool;
struct bio_set *bs;
@ -93,9 +105,25 @@ struct crypt_config {
sector_t iv_offset;
unsigned int iv_size;
/*
* Layout of each crypto request:
*
* struct ablkcipher_request
* context
* padding
* struct dm_crypt_request
* padding
* IV
*
* The padding is added so that dm_crypt_request and the IV are
* correctly aligned.
*/
unsigned int dmreq_start;
struct ablkcipher_request *req;
char cipher[CRYPTO_MAX_ALG_NAME];
char chainmode[CRYPTO_MAX_ALG_NAME];
struct crypto_blkcipher *tfm;
struct crypto_ablkcipher *tfm;
unsigned long flags;
unsigned int key_size;
u8 key[0];
@ -108,6 +136,7 @@ struct crypt_config {
static struct kmem_cache *_crypt_io_pool;
static void clone_init(struct dm_crypt_io *, struct bio *);
static void kcryptd_queue_crypt(struct dm_crypt_io *io);
/*
* Different IV generation algorithms:
@ -188,7 +217,7 @@ static int crypt_iv_essiv_ctr(struct crypt_config *cc, struct dm_target *ti,
return PTR_ERR(essiv_tfm);
}
if (crypto_cipher_blocksize(essiv_tfm) !=
crypto_blkcipher_ivsize(cc->tfm)) {
crypto_ablkcipher_ivsize(cc->tfm)) {
ti->error = "Block size of ESSIV cipher does "
"not match IV size of block cipher";
crypto_free_cipher(essiv_tfm);
@ -225,7 +254,7 @@ static int crypt_iv_essiv_gen(struct crypt_config *cc, u8 *iv, sector_t sector)
static int crypt_iv_benbi_ctr(struct crypt_config *cc, struct dm_target *ti,
const char *opts)
{
unsigned int bs = crypto_blkcipher_blocksize(cc->tfm);
unsigned bs = crypto_ablkcipher_blocksize(cc->tfm);
int log = ilog2(bs);
/* we need to calculate how far we must shift the sector count
@ -289,42 +318,10 @@ static struct crypt_iv_operations crypt_iv_null_ops = {
.generator = crypt_iv_null_gen
};
static int
crypt_convert_scatterlist(struct crypt_config *cc, struct scatterlist *out,
struct scatterlist *in, unsigned int length,
int write, sector_t sector)
{
u8 iv[cc->iv_size] __attribute__ ((aligned(__alignof__(u64))));
struct blkcipher_desc desc = {
.tfm = cc->tfm,
.info = iv,
.flags = CRYPTO_TFM_REQ_MAY_SLEEP,
};
int r;
if (cc->iv_gen_ops) {
r = cc->iv_gen_ops->generator(cc, iv, sector);
if (r < 0)
return r;
if (write)
r = crypto_blkcipher_encrypt_iv(&desc, out, in, length);
else
r = crypto_blkcipher_decrypt_iv(&desc, out, in, length);
} else {
if (write)
r = crypto_blkcipher_encrypt(&desc, out, in, length);
else
r = crypto_blkcipher_decrypt(&desc, out, in, length);
}
return r;
}
static void crypt_convert_init(struct crypt_config *cc,
struct convert_context *ctx,
struct bio *bio_out, struct bio *bio_in,
sector_t sector, int write)
sector_t sector)
{
ctx->bio_in = bio_in;
ctx->bio_out = bio_out;
@ -333,7 +330,79 @@ static void crypt_convert_init(struct crypt_config *cc,
ctx->idx_in = bio_in ? bio_in->bi_idx : 0;
ctx->idx_out = bio_out ? bio_out->bi_idx : 0;
ctx->sector = sector + cc->iv_offset;
ctx->write = write;
init_completion(&ctx->restart);
/*
* Crypto operation can be asynchronous,
* ctx->pending is increased after request submission.
* We need to ensure that we don't call the crypt finish
* operation before pending got incremented
* (dependent on crypt submission return code).
*/
atomic_set(&ctx->pending, 2);
}
static int crypt_convert_block(struct crypt_config *cc,
struct convert_context *ctx,
struct ablkcipher_request *req)
{
struct bio_vec *bv_in = bio_iovec_idx(ctx->bio_in, ctx->idx_in);
struct bio_vec *bv_out = bio_iovec_idx(ctx->bio_out, ctx->idx_out);
struct dm_crypt_request *dmreq;
u8 *iv;
int r = 0;
dmreq = (struct dm_crypt_request *)((char *)req + cc->dmreq_start);
iv = (u8 *)ALIGN((unsigned long)(dmreq + 1),
crypto_ablkcipher_alignmask(cc->tfm) + 1);
sg_init_table(&dmreq->sg_in, 1);
sg_set_page(&dmreq->sg_in, bv_in->bv_page, 1 << SECTOR_SHIFT,
bv_in->bv_offset + ctx->offset_in);
sg_init_table(&dmreq->sg_out, 1);
sg_set_page(&dmreq->sg_out, bv_out->bv_page, 1 << SECTOR_SHIFT,
bv_out->bv_offset + ctx->offset_out);
ctx->offset_in += 1 << SECTOR_SHIFT;
if (ctx->offset_in >= bv_in->bv_len) {
ctx->offset_in = 0;
ctx->idx_in++;
}
ctx->offset_out += 1 << SECTOR_SHIFT;
if (ctx->offset_out >= bv_out->bv_len) {
ctx->offset_out = 0;
ctx->idx_out++;
}
if (cc->iv_gen_ops) {
r = cc->iv_gen_ops->generator(cc, iv, ctx->sector);
if (r < 0)
return r;
}
ablkcipher_request_set_crypt(req, &dmreq->sg_in, &dmreq->sg_out,
1 << SECTOR_SHIFT, iv);
if (bio_data_dir(ctx->bio_in) == WRITE)
r = crypto_ablkcipher_encrypt(req);
else
r = crypto_ablkcipher_decrypt(req);
return r;
}
static void kcryptd_async_done(struct crypto_async_request *async_req,
int error);
static void crypt_alloc_req(struct crypt_config *cc,
struct convert_context *ctx)
{
if (!cc->req)
cc->req = mempool_alloc(cc->req_pool, GFP_NOIO);
ablkcipher_request_set_tfm(cc->req, cc->tfm);
ablkcipher_request_set_callback(cc->req, CRYPTO_TFM_REQ_MAY_BACKLOG |
CRYPTO_TFM_REQ_MAY_SLEEP,
kcryptd_async_done, ctx);
}
/*
@ -346,36 +415,38 @@ static int crypt_convert(struct crypt_config *cc,
while(ctx->idx_in < ctx->bio_in->bi_vcnt &&
ctx->idx_out < ctx->bio_out->bi_vcnt) {
struct bio_vec *bv_in = bio_iovec_idx(ctx->bio_in, ctx->idx_in);
struct bio_vec *bv_out = bio_iovec_idx(ctx->bio_out, ctx->idx_out);
struct scatterlist sg_in, sg_out;
sg_init_table(&sg_in, 1);
sg_set_page(&sg_in, bv_in->bv_page, 1 << SECTOR_SHIFT, bv_in->bv_offset + ctx->offset_in);
crypt_alloc_req(cc, ctx);
sg_init_table(&sg_out, 1);
sg_set_page(&sg_out, bv_out->bv_page, 1 << SECTOR_SHIFT, bv_out->bv_offset + ctx->offset_out);
r = crypt_convert_block(cc, ctx, cc->req);
ctx->offset_in += sg_in.length;
if (ctx->offset_in >= bv_in->bv_len) {
ctx->offset_in = 0;
ctx->idx_in++;
switch (r) {
case -EBUSY:
wait_for_completion(&ctx->restart);
INIT_COMPLETION(ctx->restart);
/* fall through*/
case -EINPROGRESS:
atomic_inc(&ctx->pending);
cc->req = NULL;
r = 0;
/* fall through*/
case 0:
ctx->sector++;
continue;
}
ctx->offset_out += sg_out.length;
if (ctx->offset_out >= bv_out->bv_len) {
ctx->offset_out = 0;
ctx->idx_out++;
}
r = crypt_convert_scatterlist(cc, &sg_out, &sg_in, sg_in.length,
ctx->write, ctx->sector);
if (r < 0)
break;
ctx->sector++;
break;
}
/*
* If there are pending crypto operation run async
* code. Otherwise process return code synchronously.
* The step of 2 ensures that async finish doesn't
* call crypto finish too early.
*/
if (atomic_sub_return(2, &ctx->pending))
return -EINPROGRESS;
return r;
}
@ -455,18 +526,14 @@ static void crypt_free_buffer_pages(struct crypt_config *cc, struct bio *clone)
* One of the bios was finished. Check for completion of
* the whole request and correctly clean up the buffer.
*/
static void crypt_dec_pending(struct dm_crypt_io *io, int error)
static void crypt_dec_pending(struct dm_crypt_io *io)
{
struct crypt_config *cc = (struct crypt_config *) io->target->private;
if (error < 0)
io->error = error;
struct crypt_config *cc = io->target->private;
if (!atomic_dec_and_test(&io->pending))
return;
bio_endio(io->base_bio, io->error);
mempool_free(io, cc->io_pool);
}
@ -484,30 +551,11 @@ static void crypt_dec_pending(struct dm_crypt_io *io, int error)
* starved by new requests which can block in the first stages due
* to memory allocation.
*/
static void kcryptd_do_work(struct work_struct *work);
static void kcryptd_do_crypt(struct work_struct *work);
static void kcryptd_queue_io(struct dm_crypt_io *io)
{
struct crypt_config *cc = io->target->private;
INIT_WORK(&io->work, kcryptd_do_work);
queue_work(cc->io_queue, &io->work);
}
static void kcryptd_queue_crypt(struct dm_crypt_io *io)
{
struct crypt_config *cc = io->target->private;
INIT_WORK(&io->work, kcryptd_do_crypt);
queue_work(cc->crypt_queue, &io->work);
}
static void crypt_endio(struct bio *clone, int error)
{
struct dm_crypt_io *io = clone->bi_private;
struct crypt_config *cc = io->target->private;
unsigned read_io = bio_data_dir(clone) == READ;
unsigned rw = bio_data_dir(clone);
if (unlikely(!bio_flagged(clone, BIO_UPTODATE) && !error))
error = -EIO;
@ -515,21 +563,20 @@ static void crypt_endio(struct bio *clone, int error)
/*
* free the processed pages
*/
if (!read_io) {
if (rw == WRITE)
crypt_free_buffer_pages(cc, clone);
goto out;
bio_put(clone);
if (rw == READ && !error) {
kcryptd_queue_crypt(io);
return;
}
if (unlikely(error))
goto out;
io->error = error;
bio_put(clone);
kcryptd_queue_crypt(io);
return;
out:
bio_put(clone);
crypt_dec_pending(io, error);
crypt_dec_pending(io);
}
static void clone_init(struct dm_crypt_io *io, struct bio *clone)
@ -543,12 +590,11 @@ static void clone_init(struct dm_crypt_io *io, struct bio *clone)
clone->bi_destructor = dm_crypt_bio_destructor;
}
static void process_read(struct dm_crypt_io *io)
static void kcryptd_io_read(struct dm_crypt_io *io)
{
struct crypt_config *cc = io->target->private;
struct bio *base_bio = io->base_bio;
struct bio *clone;
sector_t sector = base_bio->bi_sector - io->target->begin;
atomic_inc(&io->pending);
@ -559,7 +605,8 @@ static void process_read(struct dm_crypt_io *io)
*/
clone = bio_alloc_bioset(GFP_NOIO, bio_segments(base_bio), cc->bs);
if (unlikely(!clone)) {
crypt_dec_pending(io, -ENOMEM);
io->error = -ENOMEM;
crypt_dec_pending(io);
return;
}
@ -567,25 +614,71 @@ static void process_read(struct dm_crypt_io *io)
clone->bi_idx = 0;
clone->bi_vcnt = bio_segments(base_bio);
clone->bi_size = base_bio->bi_size;
clone->bi_sector = cc->start + sector;
clone->bi_sector = cc->start + io->sector;
memcpy(clone->bi_io_vec, bio_iovec(base_bio),
sizeof(struct bio_vec) * clone->bi_vcnt);
generic_make_request(clone);
}
static void process_write(struct dm_crypt_io *io)
static void kcryptd_io_write(struct dm_crypt_io *io)
{
struct bio *clone = io->ctx.bio_out;
generic_make_request(clone);
}
static void kcryptd_io(struct work_struct *work)
{
struct dm_crypt_io *io = container_of(work, struct dm_crypt_io, work);
if (bio_data_dir(io->base_bio) == READ)
kcryptd_io_read(io);
else
kcryptd_io_write(io);
}
static void kcryptd_queue_io(struct dm_crypt_io *io)
{
struct crypt_config *cc = io->target->private;
INIT_WORK(&io->work, kcryptd_io);
queue_work(cc->io_queue, &io->work);
}
static void kcryptd_crypt_write_io_submit(struct dm_crypt_io *io,
int error, int async)
{
struct bio *clone = io->ctx.bio_out;
struct crypt_config *cc = io->target->private;
if (unlikely(error < 0)) {
crypt_free_buffer_pages(cc, clone);
bio_put(clone);
io->error = -EIO;
return;
}
/* crypt_convert should have filled the clone bio */
BUG_ON(io->ctx.idx_out < clone->bi_vcnt);
clone->bi_sector = cc->start + io->sector;
io->sector += bio_sectors(clone);
if (async)
kcryptd_queue_io(io);
else {
atomic_inc(&io->pending);
generic_make_request(clone);
}
}
static void kcryptd_crypt_write_convert_loop(struct dm_crypt_io *io)
{
struct crypt_config *cc = io->target->private;
struct bio *base_bio = io->base_bio;
struct bio *clone;
struct convert_context ctx;
unsigned remaining = base_bio->bi_size;
sector_t sector = base_bio->bi_sector - io->target->begin;
atomic_inc(&io->pending);
crypt_convert_init(cc, &ctx, NULL, base_bio, sector, 1);
unsigned remaining = io->base_bio->bi_size;
int r;
/*
* The allocated buffers can be smaller than the whole bio,
@ -594,70 +687,110 @@ static void process_write(struct dm_crypt_io *io)
while (remaining) {
clone = crypt_alloc_buffer(io, remaining);
if (unlikely(!clone)) {
crypt_dec_pending(io, -ENOMEM);
io->error = -ENOMEM;
return;
}
ctx.bio_out = clone;
ctx.idx_out = 0;
io->ctx.bio_out = clone;
io->ctx.idx_out = 0;
if (unlikely(crypt_convert(cc, &ctx) < 0)) {
crypt_free_buffer_pages(cc, clone);
bio_put(clone);
crypt_dec_pending(io, -EIO);
return;
}
/* crypt_convert should have filled the clone bio */
BUG_ON(ctx.idx_out < clone->bi_vcnt);
clone->bi_sector = cc->start + sector;
remaining -= clone->bi_size;
sector += bio_sectors(clone);
/* Grab another reference to the io struct
* before we kick off the request */
if (remaining)
r = crypt_convert(cc, &io->ctx);
if (r != -EINPROGRESS) {
kcryptd_crypt_write_io_submit(io, r, 0);
if (unlikely(r < 0))
return;
} else
atomic_inc(&io->pending);
generic_make_request(clone);
/* Do not reference clone after this - it
* may be gone already. */
/* out of memory -> run queues */
if (remaining)
if (unlikely(remaining))
congestion_wait(WRITE, HZ/100);
}
}
static void process_read_endio(struct dm_crypt_io *io)
static void kcryptd_crypt_write_convert(struct dm_crypt_io *io)
{
struct crypt_config *cc = io->target->private;
struct convert_context ctx;
crypt_convert_init(cc, &ctx, io->base_bio, io->base_bio,
io->base_bio->bi_sector - io->target->begin, 0);
/*
* Prevent io from disappearing until this function completes.
*/
atomic_inc(&io->pending);
crypt_dec_pending(io, crypt_convert(cc, &ctx));
crypt_convert_init(cc, &io->ctx, NULL, io->base_bio, io->sector);
kcryptd_crypt_write_convert_loop(io);
crypt_dec_pending(io);
}
static void kcryptd_do_work(struct work_struct *work)
static void kcryptd_crypt_read_done(struct dm_crypt_io *io, int error)
{
struct dm_crypt_io *io = container_of(work, struct dm_crypt_io, work);
if (unlikely(error < 0))
io->error = -EIO;
if (bio_data_dir(io->base_bio) == READ)
process_read(io);
crypt_dec_pending(io);
}
static void kcryptd_do_crypt(struct work_struct *work)
static void kcryptd_crypt_read_convert(struct dm_crypt_io *io)
{
struct dm_crypt_io *io = container_of(work, struct dm_crypt_io, work);
struct crypt_config *cc = io->target->private;
int r = 0;
atomic_inc(&io->pending);
crypt_convert_init(cc, &io->ctx, io->base_bio, io->base_bio,
io->sector);
r = crypt_convert(cc, &io->ctx);
if (r != -EINPROGRESS)
kcryptd_crypt_read_done(io, r);
crypt_dec_pending(io);
}
static void kcryptd_async_done(struct crypto_async_request *async_req,
int error)
{
struct convert_context *ctx = async_req->data;
struct dm_crypt_io *io = container_of(ctx, struct dm_crypt_io, ctx);
struct crypt_config *cc = io->target->private;
if (error == -EINPROGRESS) {
complete(&ctx->restart);
return;
}
mempool_free(ablkcipher_request_cast(async_req), cc->req_pool);
if (!atomic_dec_and_test(&ctx->pending))
return;
if (bio_data_dir(io->base_bio) == READ)
process_read_endio(io);
kcryptd_crypt_read_done(io, error);
else
process_write(io);
kcryptd_crypt_write_io_submit(io, error, 1);
}
static void kcryptd_crypt(struct work_struct *work)
{
struct dm_crypt_io *io = container_of(work, struct dm_crypt_io, work);
if (bio_data_dir(io->base_bio) == READ)
kcryptd_crypt_read_convert(io);
else
kcryptd_crypt_write_convert(io);
}
static void kcryptd_queue_crypt(struct dm_crypt_io *io)
{
struct crypt_config *cc = io->target->private;
INIT_WORK(&io->work, kcryptd_crypt);
queue_work(cc->crypt_queue, &io->work);
}
/*
@ -733,7 +866,7 @@ static int crypt_wipe_key(struct crypt_config *cc)
static int crypt_ctr(struct dm_target *ti, unsigned int argc, char **argv)
{
struct crypt_config *cc;
struct crypto_blkcipher *tfm;
struct crypto_ablkcipher *tfm;
char *tmp;
char *cipher;
char *chainmode;
@ -787,7 +920,7 @@ static int crypt_ctr(struct dm_target *ti, unsigned int argc, char **argv)
goto bad_cipher;
}
tfm = crypto_alloc_blkcipher(cc->cipher, 0, CRYPTO_ALG_ASYNC);
tfm = crypto_alloc_ablkcipher(cc->cipher, 0, 0);
if (IS_ERR(tfm)) {
ti->error = "Error allocating crypto tfm";
goto bad_cipher;
@ -821,7 +954,7 @@ static int crypt_ctr(struct dm_target *ti, unsigned int argc, char **argv)
cc->iv_gen_ops->ctr(cc, ti, ivopts) < 0)
goto bad_ivmode;
cc->iv_size = crypto_blkcipher_ivsize(tfm);
cc->iv_size = crypto_ablkcipher_ivsize(tfm);
if (cc->iv_size)
/* at least a 64 bit sector number should fit in our buffer */
cc->iv_size = max(cc->iv_size,
@ -841,6 +974,20 @@ static int crypt_ctr(struct dm_target *ti, unsigned int argc, char **argv)
goto bad_slab_pool;
}
cc->dmreq_start = sizeof(struct ablkcipher_request);
cc->dmreq_start += crypto_ablkcipher_reqsize(tfm);
cc->dmreq_start = ALIGN(cc->dmreq_start, crypto_tfm_ctx_alignment());
cc->dmreq_start += crypto_ablkcipher_alignmask(tfm) &
~(crypto_tfm_ctx_alignment() - 1);
cc->req_pool = mempool_create_kmalloc_pool(MIN_IOS, cc->dmreq_start +
sizeof(struct dm_crypt_request) + cc->iv_size);
if (!cc->req_pool) {
ti->error = "Cannot allocate crypt request mempool";
goto bad_req_pool;
}
cc->req = NULL;
cc->page_pool = mempool_create_page_pool(MIN_POOL_PAGES, 0);
if (!cc->page_pool) {
ti->error = "Cannot allocate page mempool";
@ -853,7 +1000,7 @@ static int crypt_ctr(struct dm_target *ti, unsigned int argc, char **argv)
goto bad_bs;
}
if (crypto_blkcipher_setkey(tfm, cc->key, key_size) < 0) {
if (crypto_ablkcipher_setkey(tfm, cc->key, key_size) < 0) {
ti->error = "Error setting key";
goto bad_device;
}
@ -914,12 +1061,14 @@ static int crypt_ctr(struct dm_target *ti, unsigned int argc, char **argv)
bad_bs:
mempool_destroy(cc->page_pool);
bad_page_pool:
mempool_destroy(cc->req_pool);
bad_req_pool:
mempool_destroy(cc->io_pool);
bad_slab_pool:
if (cc->iv_gen_ops && cc->iv_gen_ops->dtr)
cc->iv_gen_ops->dtr(cc);
bad_ivmode:
crypto_free_blkcipher(tfm);
crypto_free_ablkcipher(tfm);
bad_cipher:
/* Must zero key material before freeing */
memset(cc, 0, sizeof(*cc) + cc->key_size * sizeof(u8));
@ -934,14 +1083,18 @@ static void crypt_dtr(struct dm_target *ti)
destroy_workqueue(cc->io_queue);
destroy_workqueue(cc->crypt_queue);
if (cc->req)
mempool_free(cc->req, cc->req_pool);
bioset_free(cc->bs);
mempool_destroy(cc->page_pool);
mempool_destroy(cc->req_pool);
mempool_destroy(cc->io_pool);
kfree(cc->iv_mode);
if (cc->iv_gen_ops && cc->iv_gen_ops->dtr)
cc->iv_gen_ops->dtr(cc);
crypto_free_blkcipher(cc->tfm);
crypto_free_ablkcipher(cc->tfm);
dm_put_device(ti, cc->dev);
/* Must zero key material before freeing */
@ -958,6 +1111,7 @@ static int crypt_map(struct dm_target *ti, struct bio *bio,
io = mempool_alloc(cc->io_pool, GFP_NOIO);
io->target = ti;
io->base_bio = bio;
io->sector = bio->bi_sector - ti->begin;
io->error = 0;
atomic_set(&io->pending, 0);

2
drivers/md/dm-exception-store.c
View File

@ -449,7 +449,7 @@ static void persistent_destroy(struct exception_store *store)
static int persistent_read_metadata(struct exception_store *store)
{
int r, new_snapshot;
int r, uninitialized_var(new_snapshot);
struct pstore *ps = get_info(store);
/*

32
drivers/md/dm-ioctl.c
View File

@ -15,6 +15,7 @@
#include <linux/slab.h>
#include <linux/dm-ioctl.h>
#include <linux/hdreg.h>
#include <linux/compat.h>
#include <asm/uaccess.h>
@ -702,7 +703,7 @@ static int dev_rename(struct dm_ioctl *param, size_t param_size)
int r;
char *new_name = (char *) param + param->data_start;
if (new_name < (char *) param->data ||
if (new_name < param->data ||
invalid_str(new_name, (void *) param + param_size)) {
DMWARN("Invalid new logical volume name supplied.");
return -EINVAL;
@ -728,7 +729,7 @@ static int dev_set_geometry(struct dm_ioctl *param, size_t param_size)
if (!md)
return -ENXIO;
if (geostr < (char *) param->data ||
if (geostr < param->data ||
invalid_str(geostr, (void *) param + param_size)) {
DMWARN("Invalid geometry supplied.");
goto out;
@ -1350,10 +1351,10 @@ static int copy_params(struct dm_ioctl __user *user, struct dm_ioctl **param)
{
struct dm_ioctl tmp, *dmi;
if (copy_from_user(&tmp, user, sizeof(tmp)))
if (copy_from_user(&tmp, user, sizeof(tmp) - sizeof(tmp.data)))
return -EFAULT;
if (tmp.data_size < sizeof(tmp))
if (tmp.data_size < (sizeof(tmp) - sizeof(tmp.data)))
return -EINVAL;
dmi = vmalloc(tmp.data_size);
@ -1397,13 +1398,11 @@ static int validate_params(uint cmd, struct dm_ioctl *param)
return 0;
}
static int ctl_ioctl(struct inode *inode, struct file *file,
uint command, ulong u)
static int ctl_ioctl(uint command, struct dm_ioctl __user *user)
{
int r = 0;
unsigned int cmd;
struct dm_ioctl *param;
struct dm_ioctl __user *user = (struct dm_ioctl __user *) u;
struct dm_ioctl *uninitialized_var(param);
ioctl_fn fn = NULL;
size_t param_size;
@ -1471,8 +1470,23 @@ static int ctl_ioctl(struct inode *inode, struct file *file,
return r;
}
static long dm_ctl_ioctl(struct file *file, uint command, ulong u)
{
return (long)ctl_ioctl(command, (struct dm_ioctl __user *)u);
}
#ifdef CONFIG_COMPAT
static long dm_compat_ctl_ioctl(struct file *file, uint command, ulong u)
{
return (long)dm_ctl_ioctl(file, command, (ulong) compat_ptr(u));
}
#else
#define dm_compat_ctl_ioctl NULL
#endif
static const struct file_operations _ctl_fops = {
.ioctl = ctl_ioctl,
.unlocked_ioctl = dm_ctl_ioctl,
.compat_ioctl = dm_compat_ctl_ioctl,
.owner = THIS_MODULE,
};

51
drivers/md/dm-log.c
View File

@ -41,7 +41,7 @@ int dm_unregister_dirty_log_type(struct dirty_log_type *type)
return 0;
}
static struct dirty_log_type *get_type(const char *type_name)
static struct dirty_log_type *_get_type(const char *type_name)
{
struct dirty_log_type *type;
@ -61,6 +61,55 @@ static struct dirty_log_type *get_type(const char *type_name)
return NULL;
}
/*
* get_type
* @type_name
*
* Attempt to retrieve the dirty_log_type by name. If not already
* available, attempt to load the appropriate module.
*
* Log modules are named "dm-log-" followed by the 'type_name'.
* Modules may contain multiple types.
* This function will first try the module "dm-log-<type_name>",
* then truncate 'type_name' on the last '-' and try again.
*
* For example, if type_name was "clustered-disk", it would search
* 'dm-log-clustered-disk' then 'dm-log-clustered'.
*
* Returns: dirty_log_type* on success, NULL on failure
*/
static struct dirty_log_type *get_type(const char *type_name)
{
char *p, *type_name_dup;
struct dirty_log_type *type;
type = _get_type(type_name);
if (type)
return type;
type_name_dup = kstrdup(type_name, GFP_KERNEL);
if (!type_name_dup) {
DMWARN("No memory left to attempt log module load for \"%s\"",
type_name);
return NULL;
}
while (request_module("dm-log-%s", type_name_dup) ||
!(type = _get_type(type_name))) {
p = strrchr(type_name_dup, '-');
if (!p)
break;
p[0] = '\0';
}
if (!type)
DMWARN("Module for logging type \"%s\" not found.", type_name);
kfree(type_name_dup);
return type;
}
static void put_type(struct dirty_log_type *type)
{
spin_lock(&_lock);

2
drivers/md/dm-mpath.c
View File

@ -106,7 +106,7 @@ typedef int (*action_fn) (struct pgpath *pgpath);
static struct kmem_cache *_mpio_cache;
struct workqueue_struct *kmultipathd;
static struct workqueue_struct *kmultipathd;
static void process_queued_ios(struct work_struct *work);
static void trigger_event(struct work_struct *work);

674
drivers/md/dm-raid1.c
View File

@ -6,6 +6,7 @@
#include "dm.h"
#include "dm-bio-list.h"
#include "dm-bio-record.h"
#include "dm-io.h"
#include "dm-log.h"
#include "kcopyd.h"
@ -20,6 +21,7 @@
#include <linux/vmalloc.h>
#include <linux/workqueue.h>
#include <linux/log2.h>
#include <linux/hardirq.h>
#define DM_MSG_PREFIX "raid1"
#define DM_IO_PAGES 64
@ -113,9 +115,16 @@ struct region {
/*-----------------------------------------------------------------
* Mirror set structures.
*---------------------------------------------------------------*/
enum dm_raid1_error {
DM_RAID1_WRITE_ERROR,
DM_RAID1_SYNC_ERROR,
DM_RAID1_READ_ERROR
};
struct mirror {
struct mirror_set *ms;
atomic_t error_count;
uint32_t error_type;
struct dm_dev *dev;
sector_t offset;
};
@ -127,21 +136,25 @@ struct mirror_set {
struct kcopyd_client *kcopyd_client;
uint64_t features;
spinlock_t lock; /* protects the next two lists */
spinlock_t lock; /* protects the lists */
struct bio_list reads;
struct bio_list writes;
struct bio_list failures;
struct dm_io_client *io_client;
mempool_t *read_record_pool;
/* recovery */
region_t nr_regions;
int in_sync;
int log_failure;
atomic_t suspend;
struct mirror *default_mirror; /* Default mirror */
atomic_t default_mirror; /* Default mirror */
struct workqueue_struct *kmirrord_wq;
struct work_struct kmirrord_work;
struct work_struct trigger_event;
unsigned int nr_mirrors;
struct mirror mirror[0];
@ -362,6 +375,16 @@ static void complete_resync_work(struct region *reg, int success)
struct region_hash *rh = reg->rh;
rh->log->type->set_region_sync(rh->log, reg->key, success);
/*
* Dispatch the bios before we call 'wake_up_all'.
* This is important because if we are suspending,
* we want to know that recovery is complete and
* the work queue is flushed. If we wake_up_all
* before we dispatch_bios (queue bios and call wake()),
* then we risk suspending before the work queue
* has been properly flushed.
*/
dispatch_bios(rh->ms, &reg->delayed_bios);
if (atomic_dec_and_test(&rh->recovery_in_flight))
wake_up_all(&_kmirrord_recovery_stopped);
@ -626,24 +649,101 @@ static void rh_start_recovery(struct region_hash *rh)
wake(rh->ms);
}
#define MIN_READ_RECORDS 20
struct dm_raid1_read_record {
struct mirror *m;
struct dm_bio_details details;
};
/*
* Every mirror should look like this one.
*/
#define DEFAULT_MIRROR 0
/*
* This is yucky. We squirrel the mirror_set struct away inside
* bi_next for write buffers. This is safe since the bh
* This is yucky. We squirrel the mirror struct away inside
* bi_next for read/write buffers. This is safe since the bh
* doesn't get submitted to the lower levels of block layer.
*/
static struct mirror_set *bio_get_ms(struct bio *bio)
static struct mirror *bio_get_m(struct bio *bio)
{
return (struct mirror_set *) bio->bi_next;
return (struct mirror *) bio->bi_next;
}
static void bio_set_ms(struct bio *bio, struct mirror_set *ms)
static void bio_set_m(struct bio *bio, struct mirror *m)
{
bio->bi_next = (struct bio *) ms;
bio->bi_next = (struct bio *) m;
}
static struct mirror *get_default_mirror(struct mirror_set *ms)
{
return &ms->mirror[atomic_read(&ms->default_mirror)];
}
static void set_default_mirror(struct mirror *m)
{
struct mirror_set *ms = m->ms;
struct mirror *m0 = &(ms->mirror[0]);
atomic_set(&ms->default_mirror, m - m0);
}
/* fail_mirror
* @m: mirror device to fail
* @error_type: one of the enum's, DM_RAID1_*_ERROR
*
* If errors are being handled, record the type of
* error encountered for this device. If this type
* of error has already been recorded, we can return;
* otherwise, we must signal userspace by triggering
* an event. Additionally, if the device is the
* primary device, we must choose a new primary, but
* only if the mirror is in-sync.
*
* This function must not block.
*/
static void fail_mirror(struct mirror *m, enum dm_raid1_error error_type)
{
struct mirror_set *ms = m->ms;
struct mirror *new;
if (!errors_handled(ms))
return;
/*
* error_count is used for nothing more than a
* simple way to tell if a device has encountered
* errors.
*/
atomic_inc(&m->error_count);
if (test_and_set_bit(error_type, &m->error_type))
return;
if (m != get_default_mirror(ms))
goto out;
if (!ms->in_sync) {
/*
* Better to issue requests to same failing device
* than to risk returning corrupt data.
*/
DMERR("Primary mirror (%s) failed while out-of-sync: "
"Reads may fail.", m->dev->name);
goto out;
}
for (new = ms->mirror; new < ms->mirror + ms->nr_mirrors; new++)
if (!atomic_read(&new->error_count)) {
set_default_mirror(new);
break;
}
if (unlikely(new == ms->mirror + ms->nr_mirrors))
DMWARN("All sides of mirror have failed.");
out:
schedule_work(&ms->trigger_event);
}
/*-----------------------------------------------------------------
@ -656,15 +756,32 @@ static void bio_set_ms(struct bio *bio, struct mirror_set *ms)
static void recovery_complete(int read_err, unsigned int write_err,
void *context)
{
struct region *reg = (struct region *) context;
struct region *reg = (struct region *)context;
struct mirror_set *ms = reg->rh->ms;
int m, bit = 0;
if (read_err)
if (read_err) {
/* Read error means the failure of default mirror. */
DMERR_LIMIT("Unable to read primary mirror during recovery");
fail_mirror(get_default_mirror(ms), DM_RAID1_SYNC_ERROR);
}
if (write_err)
if (write_err) {
DMERR_LIMIT("Write error during recovery (error = 0x%x)",
write_err);
/*
* Bits correspond to devices (excluding default mirror).
* The default mirror cannot change during recovery.
*/
for (m = 0; m < ms->nr_mirrors; m++) {
if (&ms->mirror[m] == get_default_mirror(ms))
continue;
if (test_bit(bit, &write_err))
fail_mirror(ms->mirror + m,
DM_RAID1_SYNC_ERROR);
bit++;
}
}
rh_recovery_end(reg, !(read_err || write_err));
}
@ -678,7 +795,7 @@ static int recover(struct mirror_set *ms, struct region *reg)
unsigned long flags = 0;
/* fill in the source */
m = ms->default_mirror;
m = get_default_mirror(ms);
from.bdev = m->dev->bdev;
from.sector = m->offset + region_to_sector(reg->rh, reg->key);
if (reg->key == (ms->nr_regions - 1)) {
@ -694,7 +811,7 @@ static int recover(struct mirror_set *ms, struct region *reg)
/* fill in the destinations */
for (i = 0, dest = to; i < ms->nr_mirrors; i++) {
if (&ms->mirror[i] == ms->default_mirror)
if (&ms->mirror[i] == get_default_mirror(ms))
continue;
m = ms->mirror + i;
@ -748,17 +865,105 @@ static void do_recovery(struct mirror_set *ms)
*---------------------------------------------------------------*/
static struct mirror *choose_mirror(struct mirror_set *ms, sector_t sector)
{
/* FIXME: add read balancing */
return ms->default_mirror;
struct mirror *m = get_default_mirror(ms);
do {
if (likely(!atomic_read(&m->error_count)))
return m;
if (m-- == ms->mirror)
m += ms->nr_mirrors;
} while (m != get_default_mirror(ms));
return NULL;
}
static int default_ok(struct mirror *m)
{
struct mirror *default_mirror = get_default_mirror(m->ms);
return !atomic_read(&default_mirror->error_count);
}
static int mirror_available(struct mirror_set *ms, struct bio *bio)
{
region_t region = bio_to_region(&ms->rh, bio);
if (ms->rh.log->type->in_sync(ms->rh.log, region, 0))
return choose_mirror(ms, bio->bi_sector) ? 1 : 0;
return 0;
}
/*
* remap a buffer to a particular mirror.
*/
static void map_bio(struct mirror_set *ms, struct mirror *m, struct bio *bio)
static sector_t map_sector(struct mirror *m, struct bio *bio)
{
return m->offset + (bio->bi_sector - m->ms->ti->begin);
}
static void map_bio(struct mirror *m, struct bio *bio)
{
bio->bi_bdev = m->dev->bdev;
bio->bi_sector = m->offset + (bio->bi_sector - ms->ti->begin);
bio->bi_sector = map_sector(m, bio);
}
static void map_region(struct io_region *io, struct mirror *m,
struct bio *bio)
{
io->bdev = m->dev->bdev;
io->sector = map_sector(m, bio);
io->count = bio->bi_size >> 9;
}
/*-----------------------------------------------------------------
* Reads
*---------------------------------------------------------------*/
static void read_callback(unsigned long error, void *context)
{
struct bio *bio = context;
struct mirror *m;
m = bio_get_m(bio);
bio_set_m(bio, NULL);
if (likely(!error)) {
bio_endio(bio, 0);
return;
}
fail_mirror(m, DM_RAID1_READ_ERROR);
if (likely(default_ok(m)) || mirror_available(m->ms, bio)) {
DMWARN_LIMIT("Read failure on mirror device %s. "
"Trying alternative device.",
m->dev->name);
queue_bio(m->ms, bio, bio_rw(bio));
return;
}
DMERR_LIMIT("Read failure on mirror device %s. Failing I/O.",
m->dev->name);
bio_endio(bio, -EIO);
}
/* Asynchronous read. */
static void read_async_bio(struct mirror *m, struct bio *bio)
{
struct io_region io;
struct dm_io_request io_req = {
.bi_rw = READ,
.mem.type = DM_IO_BVEC,
.mem.ptr.bvec = bio->bi_io_vec + bio->bi_idx,
.notify.fn = read_callback,
.notify.context = bio,
.client = m->ms->io_client,
};
map_region(&io, m, bio);
bio_set_m(bio, m);
(void) dm_io(&io_req, 1, &io, NULL);
}
static void do_reads(struct mirror_set *ms, struct bio_list *reads)
@ -769,17 +974,20 @@ static void do_reads(struct mirror_set *ms, struct bio_list *reads)
while ((bio = bio_list_pop(reads))) {
region = bio_to_region(&ms->rh, bio);
m = get_default_mirror(ms);
/*
* We can only read balance if the region is in sync.
*/
if (rh_in_sync(&ms->rh, region, 1))
if (likely(rh_in_sync(&ms->rh, region, 1)))
m = choose_mirror(ms, bio->bi_sector);
else
m = ms->default_mirror;
else if (m && atomic_read(&m->error_count))
m = NULL;
map_bio(ms, m, bio);
generic_make_request(bio);
if (likely(m))
read_async_bio(m, bio);
else
bio_endio(bio, -EIO);
}
}
@ -793,15 +1001,70 @@ static void do_reads(struct mirror_set *ms, struct bio_list *reads)
* RECOVERING: delay the io until recovery completes
* NOSYNC: increment pending, just write to the default mirror
*---------------------------------------------------------------*/
/* __bio_mark_nosync
* @ms
* @bio
* @done
* @error
*
* The bio was written on some mirror(s) but failed on other mirror(s).
* We can successfully endio the bio but should avoid the region being
* marked clean by setting the state RH_NOSYNC.
*
* This function is _not_ safe in interrupt context!
*/
static void __bio_mark_nosync(struct mirror_set *ms,
struct bio *bio, unsigned done, int error)
{
unsigned long flags;
struct region_hash *rh = &ms->rh;
struct dirty_log *log = ms->rh.log;
struct region *reg;
region_t region = bio_to_region(rh, bio);
int recovering = 0;
/* We must inform the log that the sync count has changed. */
log->type->set_region_sync(log, region, 0);
ms->in_sync = 0;
read_lock(&rh->hash_lock);
reg = __rh_find(rh, region);
read_unlock(&rh->hash_lock);
/* region hash entry should exist because write was in-flight */
BUG_ON(!reg);
BUG_ON(!list_empty(&reg->list));
spin_lock_irqsave(&rh->region_lock, flags);
/*
* Possible cases:
* 1) RH_DIRTY
* 2) RH_NOSYNC: was dirty, other preceeding writes failed
* 3) RH_RECOVERING: flushing pending writes
* Either case, the region should have not been connected to list.
*/
recovering = (reg->state == RH_RECOVERING);
reg->state = RH_NOSYNC;
BUG_ON(!list_empty(&reg->list));
spin_unlock_irqrestore(&rh->region_lock, flags);
bio_endio(bio, error);
if (recovering)
complete_resync_work(reg, 0);
}
static void write_callback(unsigned long error, void *context)
{
unsigned int i;
int uptodate = 1;
unsigned i, ret = 0;
struct bio *bio = (struct bio *) context;
struct mirror_set *ms;
int uptodate = 0;
int should_wake = 0;
unsigned long flags;
ms = bio_get_ms(bio);
bio_set_ms(bio, NULL);
ms = bio_get_m(bio)->ms;
bio_set_m(bio, NULL);
/*
* NOTE: We don't decrement the pending count here,
@ -809,26 +1072,42 @@ static void write_callback(unsigned long error, void *context)
* This way we handle both writes to SYNC and NOSYNC
* regions with the same code.
*/
if (likely(!error))
goto out;
if (error) {
for (i = 0; i < ms->nr_mirrors; i++)
if (test_bit(i, &error))
fail_mirror(ms->mirror + i, DM_RAID1_WRITE_ERROR);
else
uptodate = 1;
if (unlikely(!uptodate)) {
DMERR("All replicated volumes dead, failing I/O");
/* None of the writes succeeded, fail the I/O. */
ret = -EIO;
} else if (errors_handled(ms)) {
/*
* only error the io if all mirrors failed.
* FIXME: bogus
* Need to raise event. Since raising
* events can block, we need to do it in
* the main thread.
*/
uptodate = 0;
for (i = 0; i < ms->nr_mirrors; i++)
if (!test_bit(i, &error)) {
uptodate = 1;
break;
}
spin_lock_irqsave(&ms->lock, flags);
if (!ms->failures.head)
should_wake = 1;
bio_list_add(&ms->failures, bio);
spin_unlock_irqrestore(&ms->lock, flags);
if (should_wake)
wake(ms);
return;
}
bio_endio(bio, 0);
out:
bio_endio(bio, ret);
}
static void do_write(struct mirror_set *ms, struct bio *bio)
{
unsigned int i;
struct io_region io[KCOPYD_MAX_REGIONS+1];
struct io_region io[ms->nr_mirrors], *dest = io;
struct mirror *m;
struct dm_io_request io_req = {
.bi_rw = WRITE,
@ -839,15 +1118,14 @@ static void do_write(struct mirror_set *ms, struct bio *bio)
.client = ms->io_client,
};
for (i = 0; i < ms->nr_mirrors; i++) {
m = ms->mirror + i;
for (i = 0, m = ms->mirror; i < ms->nr_mirrors; i++, m++)
map_region(dest++, m, bio);
io[i].bdev = m->dev->bdev;
io[i].sector = m->offset + (bio->bi_sector - ms->ti->begin);
io[i].count = bio->bi_size >> 9;
}
bio_set_ms(bio, ms);
/*
* Use default mirror because we only need it to retrieve the reference
* to the mirror set in write_callback().
*/
bio_set_m(bio, get_default_mirror(ms));
(void) dm_io(&io_req, ms->nr_mirrors, io, NULL);
}
@ -900,43 +1178,125 @@ static void do_writes(struct mirror_set *ms, struct bio_list *writes)
/*
* Dispatch io.
*/
if (unlikely(ms->log_failure))
if (unlikely(ms->log_failure)) {
spin_lock_irq(&ms->lock);
bio_list_merge(&ms->failures, &sync);
spin_unlock_irq(&ms->lock);
} else
while ((bio = bio_list_pop(&sync)))
bio_endio(bio, -EIO);
else while ((bio = bio_list_pop(&sync)))
do_write(ms, bio);
do_write(ms, bio);
while ((bio = bio_list_pop(&recover)))
rh_delay(&ms->rh, bio);
while ((bio = bio_list_pop(&nosync))) {
map_bio(ms, ms->default_mirror, bio);
map_bio(get_default_mirror(ms), bio);
generic_make_request(bio);
}
}
static void do_failures(struct mirror_set *ms, struct bio_list *failures)
{
struct bio *bio;
if (!failures->head)
return;
if (!ms->log_failure) {
while ((bio = bio_list_pop(failures)))
__bio_mark_nosync(ms, bio, bio->bi_size, 0);
return;
}
/*
* If the log has failed, unattempted writes are being
* put on the failures list. We can't issue those writes
* until a log has been marked, so we must store them.
*
* If a 'noflush' suspend is in progress, we can requeue
* the I/O's to the core. This give userspace a chance
* to reconfigure the mirror, at which point the core
* will reissue the writes. If the 'noflush' flag is
* not set, we have no choice but to return errors.
*
* Some writes on the failures list may have been
* submitted before the log failure and represent a
* failure to write to one of the devices. It is ok
* for us to treat them the same and requeue them
* as well.
*/
if (dm_noflush_suspending(ms->ti)) {
while ((bio = bio_list_pop(failures)))
bio_endio(bio, DM_ENDIO_REQUEUE);
return;
}
if (atomic_read(&ms->suspend)) {
while ((bio = bio_list_pop(failures)))
bio_endio(bio, -EIO);
return;
}
spin_lock_irq(&ms->lock);
bio_list_merge(&ms->failures, failures);
spin_unlock_irq(&ms->lock);
wake(ms);
}
static void trigger_event(struct work_struct *work)
{
struct mirror_set *ms =
container_of(work, struct mirror_set, trigger_event);
dm_table_event(ms->ti->table);
}
/*-----------------------------------------------------------------
* kmirrord
*---------------------------------------------------------------*/
static void do_mirror(struct work_struct *work)
static int _do_mirror(struct work_struct *work)
{
struct mirror_set *ms =container_of(work, struct mirror_set,
kmirrord_work);
struct bio_list reads, writes;
struct bio_list reads, writes, failures;
unsigned long flags;
spin_lock(&ms->lock);
spin_lock_irqsave(&ms->lock, flags);
reads = ms->reads;
writes = ms->writes;
failures = ms->failures;
bio_list_init(&ms->reads);
bio_list_init(&ms->writes);
spin_unlock(&ms->lock);
bio_list_init(&ms->failures);
spin_unlock_irqrestore(&ms->lock, flags);
rh_update_states(&ms->rh);
do_recovery(ms);
do_reads(ms, &reads);
do_writes(ms, &writes);
do_failures(ms, &failures);
return (ms->failures.head) ? 1 : 0;
}
static void do_mirror(struct work_struct *work)
{
/*
* If _do_mirror returns 1, we give it
* another shot. This helps for cases like
* 'suspend' where we call flush_workqueue
* and expect all work to be finished. If
* a failure happens during a suspend, we
* couldn't issue a 'wake' because it would
* not be honored. Therefore, we return '1'
* from _do_mirror, and retry here.
*/
while (_do_mirror(work))
schedule();
}
/*-----------------------------------------------------------------
* Target functions
*---------------------------------------------------------------*/
@ -965,11 +1325,23 @@ static struct mirror_set *alloc_context(unsigned int nr_mirrors,
ms->nr_mirrors = nr_mirrors;
ms->nr_regions = dm_sector_div_up(ti->len, region_size);
ms->in_sync = 0;
ms->default_mirror = &ms->mirror[DEFAULT_MIRROR];
ms->log_failure = 0;
atomic_set(&ms->suspend, 0);
atomic_set(&ms->default_mirror, DEFAULT_MIRROR);
len = sizeof(struct dm_raid1_read_record);
ms->read_record_pool = mempool_create_kmalloc_pool(MIN_READ_RECORDS,
len);
if (!ms->read_record_pool) {
ti->error = "Error creating mirror read_record_pool";
kfree(ms);
return NULL;
}
ms->io_client = dm_io_client_create(DM_IO_PAGES);
if (IS_ERR(ms->io_client)) {
ti->error = "Error creating dm_io client";
mempool_destroy(ms->read_record_pool);
kfree(ms);
return NULL;
}
@ -977,6 +1349,7 @@ static struct mirror_set *alloc_context(unsigned int nr_mirrors,
if (rh_init(&ms->rh, ms, dl, region_size, ms->nr_regions)) {
ti->error = "Error creating dirty region hash";
dm_io_client_destroy(ms->io_client);
mempool_destroy(ms->read_record_pool);
kfree(ms);
return NULL;
}
@ -992,6 +1365,7 @@ static void free_context(struct mirror_set *ms, struct dm_target *ti,
dm_io_client_destroy(ms->io_client);
rh_exit(&ms->rh);
mempool_destroy(ms->read_record_pool);
kfree(ms);
}
@ -1019,6 +1393,8 @@ static int get_mirror(struct mirror_set *ms, struct dm_target *ti,
}
ms->mirror[mirror].ms = ms;
atomic_set(&(ms->mirror[mirror].error_count), 0);
ms->mirror[mirror].error_type = 0;
ms->mirror[mirror].offset = offset;
return 0;
@ -1171,6 +1547,7 @@ static int mirror_ctr(struct dm_target *ti, unsigned int argc, char **argv)
goto err_free_context;
}
INIT_WORK(&ms->kmirrord_work, do_mirror);
INIT_WORK(&ms->trigger_event, trigger_event);
r = parse_features(ms, argc, argv, &args_used);
if (r)
@ -1220,14 +1597,15 @@ static void mirror_dtr(struct dm_target *ti)
static void queue_bio(struct mirror_set *ms, struct bio *bio, int rw)
{
unsigned long flags;
int should_wake = 0;
struct bio_list *bl;
bl = (rw == WRITE) ? &ms->writes : &ms->reads;
spin_lock(&ms->lock);
spin_lock_irqsave(&ms->lock, flags);
should_wake = !(bl->head);
bio_list_add(bl, bio);
spin_unlock(&ms->lock);
spin_unlock_irqrestore(&ms->lock, flags);
if (should_wake)
wake(ms);
@ -1242,10 +1620,11 @@ static int mirror_map(struct dm_target *ti, struct bio *bio,
int r, rw = bio_rw(bio);
struct mirror *m;
struct mirror_set *ms = ti->private;
map_context->ll = bio_to_region(&ms->rh, bio);
struct dm_raid1_read_record *read_record = NULL;
if (rw == WRITE) {
/* Save region for mirror_end_io() handler */
map_context->ll = bio_to_region(&ms->rh, bio);
queue_bio(ms, bio, rw);
return DM_MAPIO_SUBMITTED;
}
@ -1255,28 +1634,34 @@ static int mirror_map(struct dm_target *ti, struct bio *bio,
if (r < 0 && r != -EWOULDBLOCK)
return r;
if (r == -EWOULDBLOCK) /* FIXME: ugly */
r = DM_MAPIO_SUBMITTED;
/*
* We don't want to fast track a recovery just for a read
* ahead. So we just let it silently fail.
* FIXME: get rid of this.
* If region is not in-sync queue the bio.
*/
if (!r && rw == READA)
return -EIO;
if (!r || (r == -EWOULDBLOCK)) {
if (rw == READA)
return -EWOULDBLOCK;
if (!r) {
/* Pass this io over to the daemon */
queue_bio(ms, bio, rw);
return DM_MAPIO_SUBMITTED;
}
/*
* The region is in-sync and we can perform reads directly.
* Store enough information so we can retry if it fails.
*/
m = choose_mirror(ms, bio->bi_sector);
if (!m)
if (unlikely(!m))
return -EIO;
map_bio(ms, m, bio);
read_record = mempool_alloc(ms->read_record_pool, GFP_NOIO);
if (likely(read_record)) {
dm_bio_record(&read_record->details, bio);
map_context->ptr = read_record;
read_record->m = m;
}
map_bio(m, bio);
return DM_MAPIO_REMAPPED;
}
@ -1285,71 +1670,173 @@ static int mirror_end_io(struct dm_target *ti, struct bio *bio,
{
int rw = bio_rw(bio);
struct mirror_set *ms = (struct mirror_set *) ti->private;
region_t region = map_context->ll;
struct mirror *m = NULL;
struct dm_bio_details *bd = NULL;
struct dm_raid1_read_record *read_record = map_context->ptr;
/*
* We need to dec pending if this was a write.
*/
if (rw == WRITE)
rh_dec(&ms->rh, region);
if (rw == WRITE) {
rh_dec(&ms->rh, map_context->ll);
return error;
}
return 0;
if (error == -EOPNOTSUPP)
goto out;
if ((error == -EWOULDBLOCK) && bio_rw_ahead(bio))
goto out;
if (unlikely(error)) {
if (!read_record) {
/*
* There wasn't enough memory to record necessary
* information for a retry or there was no other
* mirror in-sync.
*/
DMERR_LIMIT("Mirror read failed from %s.",
m->dev->name);
return -EIO;
}
DMERR("Mirror read failed from %s. Trying alternative device.",
m->dev->name);
m = read_record->m;
fail_mirror(m, DM_RAID1_READ_ERROR);
/*
* A failed read is requeued for another attempt using an intact
* mirror.
*/
if (default_ok(m) || mirror_available(ms, bio)) {
bd = &read_record->details;
dm_bio_restore(bd, bio);
mempool_free(read_record, ms->read_record_pool);
map_context->ptr = NULL;
queue_bio(ms, bio, rw);
return 1;
}
DMERR("All replicated volumes dead, failing I/O");
}
out:
if (read_record) {
mempool_free(read_record, ms->read_record_pool);
map_context->ptr = NULL;
}
return error;
}
static void mirror_presuspend(struct dm_target *ti)
{
struct mirror_set *ms = (struct mirror_set *) ti->private;
struct dirty_log *log = ms->rh.log;
atomic_set(&ms->suspend, 1);
/*
* We must finish up all the work that we've
* generated (i.e. recovery work).
*/
rh_stop_recovery(&ms->rh);
wait_event(_kmirrord_recovery_stopped,
!atomic_read(&ms->rh.recovery_in_flight));
if (log->type->presuspend && log->type->presuspend(log))
/* FIXME: need better error handling */
DMWARN("log presuspend failed");
/*
* Now that recovery is complete/stopped and the
* delayed bios are queued, we need to wait for
* the worker thread to complete. This way,
* we know that all of our I/O has been pushed.
*/
flush_workqueue(ms->kmirrord_wq);
}
static void mirror_postsuspend(struct dm_target *ti)
{
struct mirror_set *ms = (struct mirror_set *) ti->private;
struct mirror_set *ms = ti->private;
struct dirty_log *log = ms->rh.log;
rh_stop_recovery(&ms->rh);
/* Wait for all I/O we generated to complete */
wait_event(_kmirrord_recovery_stopped,
!atomic_read(&ms->rh.recovery_in_flight));
if (log->type->postsuspend && log->type->postsuspend(log))
/* FIXME: need better error handling */
DMWARN("log suspend failed");
DMWARN("log postsuspend failed");
}
static void mirror_resume(struct dm_target *ti)
{
struct mirror_set *ms = (struct mirror_set *) ti->private;
struct mirror_set *ms = ti->private;
struct dirty_log *log = ms->rh.log;
atomic_set(&ms->suspend, 0);
if (log->type->resume && log->type->resume(log))
/* FIXME: need better error handling */
DMWARN("log resume failed");
rh_start_recovery(&ms->rh);
}
/*
* device_status_char
* @m: mirror device/leg we want the status of
*
* We return one character representing the most severe error
* we have encountered.
* A => Alive - No failures
* D => Dead - A write failure occurred leaving mirror out-of-sync
* S => Sync - A sychronization failure occurred, mirror out-of-sync
* R => Read - A read failure occurred, mirror data unaffected
*
* Returns: <char>
*/
static char device_status_char(struct mirror *m)
{
if (!atomic_read(&(m->error_count)))
return 'A';
return (test_bit(DM_RAID1_WRITE_ERROR, &(m->error_type))) ? 'D' :
(test_bit(DM_RAID1_SYNC_ERROR, &(m->error_type))) ? 'S' :
(test_bit(DM_RAID1_READ_ERROR, &(m->error_type))) ? 'R' : 'U';
}
static int mirror_status(struct dm_target *ti, status_type_t type,
char *result, unsigned int maxlen)
{
unsigned int m, sz = 0;
struct mirror_set *ms = (struct mirror_set *) ti->private;
struct dirty_log *log = ms->rh.log;
char buffer[ms->nr_mirrors + 1];
switch (type) {
case STATUSTYPE_INFO:
DMEMIT("%d ", ms->nr_mirrors);
for (m = 0; m < ms->nr_mirrors; m++)
for (m = 0; m < ms->nr_mirrors; m++) {
DMEMIT("%s ", ms->mirror[m].dev->name);
buffer[m] = device_status_char(&(ms->mirror[m]));
}
buffer[m] = '\0';
DMEMIT("%llu/%llu 0 ",
(unsigned long long)ms->rh.log->type->
get_sync_count(ms->rh.log),
(unsigned long long)ms->nr_regions);
DMEMIT("%llu/%llu 1 %s ",
(unsigned long long)log->type->get_sync_count(ms->rh.log),
(unsigned long long)ms->nr_regions, buffer);
sz += ms->rh.log->type->status(ms->rh.log, type, result+sz, maxlen-sz);
sz += log->type->status(ms->rh.log, type, result+sz, maxlen-sz);
break;
case STATUSTYPE_TABLE:
sz = ms->rh.log->type->status(ms->rh.log, type, result, maxlen);
sz = log->type->status(ms->rh.log, type, result, maxlen);
DMEMIT("%d", ms->nr_mirrors);
for (m = 0; m < ms->nr_mirrors; m++)
DMEMIT(" %s %llu", ms->mirror[m].dev->name,
(unsigned long long)ms->mirror[m].offset);
(unsigned long long)ms->mirror[m].offset);
if (ms->features & DM_RAID1_HANDLE_ERRORS)
DMEMIT(" 1 handle_errors");
@ -1360,12 +1847,13 @@ static int mirror_status(struct dm_target *ti, status_type_t type,
static struct target_type mirror_target = {
.name = "mirror",
.version = {1, 0, 3},
.version = {1, 0, 20},
.module = THIS_MODULE,
.ctr = mirror_ctr,
.dtr = mirror_dtr,
.map = mirror_map,
.end_io = mirror_end_io,
.presuspend = mirror_presuspend,
.postsuspend = mirror_postsuspend,
.resume = mirror_resume,
.status = mirror_status,

95
drivers/md/dm-snap.c
View File

@ -213,11 +213,15 @@ static void unregister_snapshot(struct dm_snapshot *s)
/*
* Implementation of the exception hash tables.
* The lowest hash_shift bits of the chunk number are ignored, allowing
* some consecutive chunks to be grouped together.
*/
static int init_exception_table(struct exception_table *et, uint32_t size)
static int init_exception_table(struct exception_table *et, uint32_t size,
unsigned hash_shift)
{
unsigned int i;
et->hash_shift = hash_shift;
et->hash_mask = size - 1;
et->table = dm_vcalloc(size, sizeof(struct list_head));
if (!et->table)
@ -248,7 +252,7 @@ static void exit_exception_table(struct exception_table *et, struct kmem_cache *
static uint32_t exception_hash(struct exception_table *et, chunk_t chunk)
{
return chunk & et->hash_mask;
return (chunk >> et->hash_shift) & et->hash_mask;
}
static void insert_exception(struct exception_table *eh,
@ -275,7 +279,8 @@ static struct dm_snap_exception *lookup_exception(struct exception_table *et,
slot = &et->table[exception_hash(et, chunk)];
list_for_each_entry (e, slot, hash_list)
if (e->old_chunk == chunk)
if (chunk >= e->old_chunk &&
chunk <= e->old_chunk + dm_consecutive_chunk_count(e))
return e;
return NULL;
@ -307,6 +312,49 @@ static void free_pending_exception(struct dm_snap_pending_exception *pe)
mempool_free(pe, pending_pool);
}
static void insert_completed_exception(struct dm_snapshot *s,
struct dm_snap_exception *new_e)
{
struct exception_table *eh = &s->complete;
struct list_head *l;
struct dm_snap_exception *e = NULL;
l = &eh->table[exception_hash(eh, new_e->old_chunk)];
/* Add immediately if this table doesn't support consecutive chunks */
if (!eh->hash_shift)
goto out;
/* List is ordered by old_chunk */
list_for_each_entry_reverse(e, l, hash_list) {
/* Insert after an existing chunk? */
if (new_e->old_chunk == (e->old_chunk +
dm_consecutive_chunk_count(e) + 1) &&
new_e->new_chunk == (dm_chunk_number(e->new_chunk) +
dm_consecutive_chunk_count(e) + 1)) {
dm_consecutive_chunk_count_inc(e);
free_exception(new_e);
return;
}
/* Insert before an existing chunk? */
if (new_e->old_chunk == (e->old_chunk - 1) &&
new_e->new_chunk == (dm_chunk_number(e->new_chunk) - 1)) {
dm_consecutive_chunk_count_inc(e);
e->old_chunk--;
e->new_chunk--;
free_exception(new_e);
return;
}
if (new_e->old_chunk > e->old_chunk)
break;
}
out:
list_add(&new_e->hash_list, e ? &e->hash_list : l);
}
int dm_add_exception(struct dm_snapshot *s, chunk_t old, chunk_t new)
{
struct dm_snap_exception *e;
@ -316,8 +364,12 @@ int dm_add_exception(struct dm_snapshot *s, chunk_t old, chunk_t new)
return -ENOMEM;
e->old_chunk = old;
/* Consecutive_count is implicitly initialised to zero */
e->new_chunk = new;
insert_exception(&s->complete, e);
insert_completed_exception(s, e);
return 0;
}
@ -333,16 +385,6 @@ static int calc_max_buckets(void)
return mem;
}
/*
* Rounds a number down to a power of 2.
*/
static uint32_t round_down(uint32_t n)
{
while (n & (n - 1))
n &= (n - 1);
return n;
}
/*
* Allocate room for a suitable hash table.
*/
@ -361,9 +403,9 @@ static int init_hash_tables(struct dm_snapshot *s)
hash_size = min(origin_dev_size, cow_dev_size) >> s->chunk_shift;
hash_size = min(hash_size, max_buckets);
/* Round it down to a power of 2 */
hash_size = round_down(hash_size);
if (init_exception_table(&s->complete, hash_size))
hash_size = rounddown_pow_of_two(hash_size);
if (init_exception_table(&s->complete, hash_size,
DM_CHUNK_CONSECUTIVE_BITS))
return -ENOMEM;
/*
@ -374,7 +416,7 @@ static int init_hash_tables(struct dm_snapshot *s)
if (hash_size < 64)
hash_size = 64;
if (init_exception_table(&s->pending, hash_size)) {
if (init_exception_table(&s->pending, hash_size, 0)) {
exit_exception_table(&s->complete, exception_cache);
return -ENOMEM;
}
@ -733,7 +775,7 @@ static void pending_complete(struct dm_snap_pending_exception *pe, int success)
* Add a proper exception, and remove the
* in-flight exception from the list.
*/
insert_exception(&s->complete, e);
insert_completed_exception(s, e);
out:
remove_exception(&pe->e);
@ -867,11 +909,12 @@ __find_pending_exception(struct dm_snapshot *s, struct bio *bio)
}
static void remap_exception(struct dm_snapshot *s, struct dm_snap_exception *e,
struct bio *bio)
struct bio *bio, chunk_t chunk)
{
bio->bi_bdev = s->cow->bdev;
bio->bi_sector = chunk_to_sector(s, e->new_chunk) +
(bio->bi_sector & s->chunk_mask);
bio->bi_sector = chunk_to_sector(s, dm_chunk_number(e->new_chunk) +
(chunk - e->old_chunk)) +
(bio->bi_sector & s->chunk_mask);
}
static int snapshot_map(struct dm_target *ti, struct bio *bio,
@ -902,7 +945,7 @@ static int snapshot_map(struct dm_target *ti, struct bio *bio,
/* If the block is already remapped - use that, else remap it */
e = lookup_exception(&s->complete, chunk);
if (e) {
remap_exception(s, e, bio);
remap_exception(s, e, bio, chunk);
goto out_unlock;
}
@ -919,7 +962,7 @@ static int snapshot_map(struct dm_target *ti, struct bio *bio,
goto out_unlock;
}
remap_exception(s, &pe->e, bio);
remap_exception(s, &pe->e, bio, chunk);
bio_list_add(&pe->snapshot_bios, bio);
r = DM_MAPIO_SUBMITTED;
@ -1207,7 +1250,7 @@ static int origin_status(struct dm_target *ti, status_type_t type, char *result,
static struct target_type origin_target = {
.name = "snapshot-origin",
.version = {1, 5, 0},
.version = {1, 6, 0},
.module = THIS_MODULE,
.ctr = origin_ctr,
.dtr = origin_dtr,
@ -1218,7 +1261,7 @@ static struct target_type origin_target = {
static struct target_type snapshot_target = {
.name = "snapshot",
.version = {1, 5, 0},
.version = {1, 6, 0},
.module = THIS_MODULE,
.ctr = snapshot_ctr,
.dtr = snapshot_dtr,

50
drivers/md/dm-snap.h
View File

@ -16,19 +16,22 @@
struct exception_table {
uint32_t hash_mask;
unsigned hash_shift;
struct list_head *table;
};
/*
* The snapshot code deals with largish chunks of the disk at a
* time. Typically 64k - 256k.
* time. Typically 32k - 512k.
*/
/* FIXME: can we get away with limiting these to a uint32_t ? */
typedef sector_t chunk_t;
/*
* An exception is used where an old chunk of data has been
* replaced by a new one.
* If chunk_t is 64 bits in size, the top 8 bits of new_chunk hold the number
* of chunks that follow contiguously. Remaining bits hold the number of the
* chunk within the device.
*/
struct dm_snap_exception {
struct list_head hash_list;
@ -37,6 +40,49 @@ struct dm_snap_exception {
chunk_t new_chunk;
};
/*
* Funtions to manipulate consecutive chunks
*/
# if defined(CONFIG_LBD) || (BITS_PER_LONG == 64)
# define DM_CHUNK_CONSECUTIVE_BITS 8
# define DM_CHUNK_NUMBER_BITS 56
static inline chunk_t dm_chunk_number(chunk_t chunk)
{
return chunk & (chunk_t)((1ULL << DM_CHUNK_NUMBER_BITS) - 1ULL);
}
static inline unsigned dm_consecutive_chunk_count(struct dm_snap_exception *e)
{
return e->new_chunk >> DM_CHUNK_NUMBER_BITS;
}
static inline void dm_consecutive_chunk_count_inc(struct dm_snap_exception *e)
{
e->new_chunk += (1ULL << DM_CHUNK_NUMBER_BITS);
BUG_ON(!dm_consecutive_chunk_count(e));
}
# else
# define DM_CHUNK_CONSECUTIVE_BITS 0
static inline chunk_t dm_chunk_number(chunk_t chunk)
{
return chunk;
}
static inline unsigned dm_consecutive_chunk_count(struct dm_snap_exception *e)
{
return 0;
}
static inline void dm_consecutive_chunk_count_inc(struct dm_snap_exception *e)
{
}
# endif
/*
* Abstraction to handle the meta/layout of exception stores (the
* COW device).

105
drivers/md/dm-stripe.c
View File

@ -14,10 +14,13 @@
#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 {
@ -30,9 +33,29 @@ struct stripe_c {
uint32_t chunk_shift;
sector_t chunk_mask;
/* Needed for handling events */
struct dm_target *ti;
/* Work struct used for triggering events*/
struct work_struct kstriped_ws;
struct stripe stripe[0];
};
static struct workqueue_struct *kstriped;
/*
* 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, kstriped_ws);
dm_table_event(sc->ti->table);
}
static inline struct stripe_c *alloc_context(unsigned int stripes)
{
size_t len;
@ -63,6 +86,7 @@ static int get_stripe(struct dm_target *ti, struct stripe_c *sc,
return -ENXIO;
sc->stripe[stripe].physical_start = start;
return 0;
}
@ -135,6 +159,11 @@ static int stripe_ctr(struct dm_target *ti, unsigned int argc, char **argv)
return -ENOMEM;
}
INIT_WORK(&sc->kstriped_ws, trigger_event);
/* Set pointer to dm target; used in trigger_event */
sc->ti = ti;
sc->stripes = stripes;
sc->stripe_width = width;
ti->split_io = chunk_size;
@ -158,9 +187,11 @@ static int stripe_ctr(struct dm_target *ti, unsigned int argc, char **argv)
kfree(sc);
return r;
}
atomic_set(&(sc->stripe[i].error_count), 0);
}
ti->private = sc;
return 0;
}
@ -172,6 +203,7 @@ static void stripe_dtr(struct dm_target *ti)
for (i = 0; i < sc->stripes; i++)
dm_put_device(ti, sc->stripe[i].dev);
flush_workqueue(kstriped);
kfree(sc);
}
@ -190,16 +222,37 @@ static int stripe_map(struct dm_target *ti, struct bio *bio,
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, char *result, unsigned int 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:
result[0] = '\0';
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:
@ -213,13 +266,52 @@ static int stripe_status(struct dm_target *ti,
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_rw_ahead(bio))
return error;
if (error == -EOPNOTSUPP)
return error;
memset(major_minor, 0, sizeof(major_minor));
sprintf(major_minor, "%d:%d",
bio->bi_bdev->bd_disk->major,
bio->bi_bdev->bd_disk->first_minor);
/*
* 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)
queue_work(kstriped, &sc->kstriped_ws);
}
return error;
}
static struct target_type stripe_target = {
.name = "striped",
.version= {1, 0, 2},
.version = {1, 1, 0},
.module = THIS_MODULE,
.ctr = stripe_ctr,
.dtr = stripe_dtr,
.map = stripe_map,
.end_io = stripe_end_io,
.status = stripe_status,
};
@ -231,6 +323,13 @@ int __init dm_stripe_init(void)
if (r < 0)
DMWARN("target registration failed");
kstriped = create_singlethread_workqueue("kstriped");
if (!kstriped) {
DMERR("failed to create workqueue kstriped");
dm_unregister_target(&stripe_target);
return -ENOMEM;
}
return r;
}
@ -239,5 +338,7 @@ void dm_stripe_exit(void)
if (dm_unregister_target(&stripe_target))
DMWARN("target unregistration failed");
destroy_workqueue(kstriped);
return;
}

20
drivers/md/dm-table.c
View File

@ -287,9 +287,8 @@ static void free_devices(struct list_head *devices)
{
struct list_head *tmp, *next;
for (tmp = devices->next; tmp != devices; tmp = next) {
list_for_each_safe(tmp, next, devices) {
struct dm_dev *dd = list_entry(tmp, struct dm_dev, list);
next = tmp->next;
kfree(dd);
}
}
@ -476,7 +475,7 @@ static int __table_get_device(struct dm_table *t, struct dm_target *ti,
int mode, struct dm_dev **result)
{
int r;
dev_t dev;
dev_t uninitialized_var(dev);
struct dm_dev *dd;
unsigned int major, minor;
@ -805,7 +804,7 @@ static int setup_indexes(struct dm_table *t)
return -ENOMEM;
/* set up internal nodes, bottom-up */
for (i = t->depth - 2, total = 0; i >= 0; i--) {
for (i = t->depth - 2; i >= 0; i--) {
t->index[i] = indexes;
indexes += (KEYS_PER_NODE * t->counts[i]);
setup_btree_index(i, t);
@ -993,12 +992,11 @@ int dm_table_resume_targets(struct dm_table *t)
int dm_table_any_congested(struct dm_table *t, int bdi_bits)
{
struct list_head *d, *devices;
struct dm_dev *dd;
struct list_head *devices = dm_table_get_devices(t);
int r = 0;
devices = dm_table_get_devices(t);
for (d = devices->next; d != devices; d = d->next) {
struct dm_dev *dd = list_entry(d, struct dm_dev, list);
list_for_each_entry(dd, devices, list) {
struct request_queue *q = bdev_get_queue(dd->bdev);
r |= bdi_congested(&q->backing_dev_info, bdi_bits);
}
@ -1008,10 +1006,10 @@ int dm_table_any_congested(struct dm_table *t, int bdi_bits)
void dm_table_unplug_all(struct dm_table *t)
{
struct list_head *d, *devices = dm_table_get_devices(t);
struct dm_dev *dd;
struct list_head *devices = dm_table_get_devices(t);
for (d = devices->next; d != devices; d = d->next) {
struct dm_dev *dd = list_entry(d, struct dm_dev, list);
list_for_each_entry(dd, devices, list) {
struct request_queue *q = bdev_get_queue(dd->bdev);
blk_unplug(q);

238
drivers/md/dm.c
View File

@ -71,9 +71,22 @@ union map_info *dm_get_mapinfo(struct bio *bio)
#define DMF_DELETING 4
#define DMF_NOFLUSH_SUSPENDING 5
/*
* Work processed by per-device workqueue.
*/
struct dm_wq_req {
enum {
DM_WQ_FLUSH_ALL,
DM_WQ_FLUSH_DEFERRED,
} type;
struct work_struct work;
struct mapped_device *md;
void *context;
};
struct mapped_device {
struct rw_semaphore io_lock;
struct semaphore suspend_lock;
struct mutex suspend_lock;
spinlock_t pushback_lock;
rwlock_t map_lock;
atomic_t holders;
@ -95,6 +108,11 @@ struct mapped_device {
struct bio_list deferred;
struct bio_list pushback;
/*
* Processing queue (flush/barriers)
*/
struct workqueue_struct *wq;
/*
* The current mapping.
*/
@ -181,7 +199,7 @@ static void local_exit(void)
DMINFO("cleaned up");
}
int (*_inits[])(void) __initdata = {
static int (*_inits[])(void) __initdata = {
local_init,
dm_target_init,
dm_linear_init,
@ -189,7 +207,7 @@ int (*_inits[])(void) __initdata = {
dm_interface_init,
};
void (*_exits[])(void) = {
static void (*_exits[])(void) = {
local_exit,
dm_target_exit,
dm_linear_exit,
@ -982,7 +1000,7 @@ static struct mapped_device *alloc_dev(int minor)
}
if (!try_module_get(THIS_MODULE))
goto bad0;
goto bad_module_get;
/* get a minor number for the dev */
if (minor == DM_ANY_MINOR)
@ -990,11 +1008,11 @@ static struct mapped_device *alloc_dev(int minor)
else
r = specific_minor(md, minor);
if (r < 0)
goto bad1;
goto bad_minor;
memset(md, 0, sizeof(*md));
init_rwsem(&md->io_lock);
init_MUTEX(&md->suspend_lock);
mutex_init(&md->suspend_lock);
spin_lock_init(&md->pushback_lock);
rwlock_init(&md->map_lock);
atomic_set(&md->holders, 1);
@ -1006,7 +1024,7 @@ static struct mapped_device *alloc_dev(int minor)
md->queue = blk_alloc_queue(GFP_KERNEL);
if (!md->queue)
goto bad1_free_minor;
goto bad_queue;
md->queue->queuedata = md;
md->queue->backing_dev_info.congested_fn = dm_any_congested;
@ -1017,11 +1035,11 @@ static struct mapped_device *alloc_dev(int minor)
md->io_pool = mempool_create_slab_pool(MIN_IOS, _io_cache);
if (!md->io_pool)
goto bad2;
goto bad_io_pool;
md->tio_pool = mempool_create_slab_pool(MIN_IOS, _tio_cache);
if (!md->tio_pool)
goto bad3;
goto bad_tio_pool;
md->bs = bioset_create(16, 16);
if (!md->bs)
@ -1029,7 +1047,7 @@ static struct mapped_device *alloc_dev(int minor)
md->disk = alloc_disk(1);
if (!md->disk)
goto bad4;
goto bad_disk;
atomic_set(&md->pending, 0);
init_waitqueue_head(&md->wait);
@ -1044,6 +1062,10 @@ static struct mapped_device *alloc_dev(int minor)
add_disk(md->disk);
format_dev_t(md->name, MKDEV(_major, minor));
md->wq = create_singlethread_workqueue("kdmflush");
if (!md->wq)
goto bad_thread;
/* Populate the mapping, nobody knows we exist yet */
spin_lock(&_minor_lock);
old_md = idr_replace(&_minor_idr, md, minor);
@ -1053,19 +1075,21 @@ static struct mapped_device *alloc_dev(int minor)
return md;
bad4:
bad_thread:
put_disk(md->disk);
bad_disk:
bioset_free(md->bs);
bad_no_bioset:
bad_no_bioset:
mempool_destroy(md->tio_pool);
bad3:
bad_tio_pool:
mempool_destroy(md->io_pool);
bad2:
bad_io_pool:
blk_cleanup_queue(md->queue);
bad1_free_minor:
bad_queue:
free_minor(minor);
bad1:
bad_minor:
module_put(THIS_MODULE);
bad0:
bad_module_get:
kfree(md);
return NULL;
}
@ -1080,6 +1104,7 @@ static void free_dev(struct mapped_device *md)
unlock_fs(md);
bdput(md->suspended_bdev);
}
destroy_workqueue(md->wq);
mempool_destroy(md->tio_pool);
mempool_destroy(md->io_pool);
bioset_free(md->bs);
@ -1259,20 +1284,91 @@ void dm_put(struct mapped_device *md)
}
EXPORT_SYMBOL_GPL(dm_put);
static int dm_wait_for_completion(struct mapped_device *md)
{
int r = 0;
while (1) {
set_current_state(TASK_INTERRUPTIBLE);
smp_mb();
if (!atomic_read(&md->pending))
break;
if (signal_pending(current)) {
r = -EINTR;
break;
}
io_schedule();
}
set_current_state(TASK_RUNNING);
return r;
}
/*
* Process the deferred bios
*/
static void __flush_deferred_io(struct mapped_device *md, struct bio *c)
static void __flush_deferred_io(struct mapped_device *md)
{
struct bio *n;
struct bio *c;
while (c) {
n = c->bi_next;
c->bi_next = NULL;
while ((c = bio_list_pop(&md->deferred))) {
if (__split_bio(md, c))
bio_io_error(c);
c = n;
}
clear_bit(DMF_BLOCK_IO, &md->flags);
}
static void __merge_pushback_list(struct mapped_device *md)
{
unsigned long flags;
spin_lock_irqsave(&md->pushback_lock, flags);
clear_bit(DMF_NOFLUSH_SUSPENDING, &md->flags);
bio_list_merge_head(&md->deferred, &md->pushback);
bio_list_init(&md->pushback);
spin_unlock_irqrestore(&md->pushback_lock, flags);
}
static void dm_wq_work(struct work_struct *work)
{
struct dm_wq_req *req = container_of(work, struct dm_wq_req, work);
struct mapped_device *md = req->md;
down_write(&md->io_lock);
switch (req->type) {
case DM_WQ_FLUSH_ALL:
__merge_pushback_list(md);
/* pass through */
case DM_WQ_FLUSH_DEFERRED:
__flush_deferred_io(md);
break;
default:
DMERR("dm_wq_work: unrecognised work type %d", req->type);
BUG();
}
up_write(&md->io_lock);
}
static void dm_wq_queue(struct mapped_device *md, int type, void *context,
struct dm_wq_req *req)
{
req->type = type;
req->md = md;
req->context = context;
INIT_WORK(&req->work, dm_wq_work);
queue_work(md->wq, &req->work);
}
static void dm_queue_flush(struct mapped_device *md, int type, void *context)
{
struct dm_wq_req req;
dm_wq_queue(md, type, context, &req);
flush_workqueue(md->wq);
}
/*
@ -1282,7 +1378,7 @@ int dm_swap_table(struct mapped_device *md, struct dm_table *table)
{
int r = -EINVAL;
down(&md->suspend_lock);
mutex_lock(&md->suspend_lock);
/* device must be suspended */
if (!dm_suspended(md))
@ -1297,7 +1393,7 @@ int dm_swap_table(struct mapped_device *md, struct dm_table *table)
r = __bind(md, table);
out:
up(&md->suspend_lock);
mutex_unlock(&md->suspend_lock);
return r;
}
@ -1346,17 +1442,17 @@ static void unlock_fs(struct mapped_device *md)
int dm_suspend(struct mapped_device *md, unsigned suspend_flags)
{
struct dm_table *map = NULL;
unsigned long flags;
DECLARE_WAITQUEUE(wait, current);
struct bio *def;
int r = -EINVAL;
int r = 0;
int do_lockfs = suspend_flags & DM_SUSPEND_LOCKFS_FLAG ? 1 : 0;
int noflush = suspend_flags & DM_SUSPEND_NOFLUSH_FLAG ? 1 : 0;
down(&md->suspend_lock);
mutex_lock(&md->suspend_lock);
if (dm_suspended(md))
if (dm_suspended(md)) {
r = -EINVAL;
goto out_unlock;
}
map = dm_get_table(md);
@ -1378,16 +1474,16 @@ int dm_suspend(struct mapped_device *md, unsigned suspend_flags)
r = -ENOMEM;
goto flush_and_out;
}
}
/*
* Flush I/O to the device.
* noflush supersedes do_lockfs, because lock_fs() needs to flush I/Os.
*/
if (do_lockfs && !noflush) {
r = lock_fs(md);
if (r)
goto out;
/*
* Flush I/O to the device. noflush supersedes do_lockfs,
* because lock_fs() needs to flush I/Os.
*/
if (do_lockfs) {
r = lock_fs(md);
if (r)
goto out;
}
}
/*
@ -1404,66 +1500,36 @@ int dm_suspend(struct mapped_device *md, unsigned suspend_flags)
dm_table_unplug_all(map);
/*
* Then we wait for the already mapped ios to
* complete.
* 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);
r = dm_wait_for_completion(md);
down_write(&md->io_lock);
remove_wait_queue(&md->wait, &wait);
if (noflush) {
spin_lock_irqsave(&md->pushback_lock, flags);
clear_bit(DMF_NOFLUSH_SUSPENDING, &md->flags);
bio_list_merge_head(&md->deferred, &md->pushback);
bio_list_init(&md->pushback);
spin_unlock_irqrestore(&md->pushback_lock, flags);
}
if (noflush)
__merge_pushback_list(md);
up_write(&md->io_lock);
/* were we interrupted ? */
r = -EINTR;
if (atomic_read(&md->pending)) {
clear_bit(DMF_BLOCK_IO, &md->flags);
def = bio_list_get(&md->deferred);
__flush_deferred_io(md, def);
up_write(&md->io_lock);
if (r < 0) {
dm_queue_flush(md, DM_WQ_FLUSH_DEFERRED, NULL);
unlock_fs(md);
goto out; /* pushback list is already flushed, so skip flush */
}
up_write(&md->io_lock);
dm_table_postsuspend_targets(map);
set_bit(DMF_SUSPENDED, &md->flags);
r = 0;
flush_and_out:
if (r && noflush) {
if (r && noflush)
/*
* Because there may be already I/Os in the pushback list,
* flush them before return.
*/
down_write(&md->io_lock);
spin_lock_irqsave(&md->pushback_lock, flags);
clear_bit(DMF_NOFLUSH_SUSPENDING, &md->flags);
bio_list_merge_head(&md->deferred, &md->pushback);
bio_list_init(&md->pushback);
spin_unlock_irqrestore(&md->pushback_lock, flags);
def = bio_list_get(&md->deferred);
__flush_deferred_io(md, def);
up_write(&md->io_lock);
}
dm_queue_flush(md, DM_WQ_FLUSH_ALL, NULL);
out:
if (r && md->suspended_bdev) {
@ -1474,17 +1540,16 @@ int dm_suspend(struct mapped_device *md, unsigned suspend_flags)
dm_table_put(map);
out_unlock:
up(&md->suspend_lock);
mutex_unlock(&md->suspend_lock);
return r;
}
int dm_resume(struct mapped_device *md)
{
int r = -EINVAL;
struct bio *def;
struct dm_table *map = NULL;
down(&md->suspend_lock);
mutex_lock(&md->suspend_lock);
if (!dm_suspended(md))
goto out;
@ -1496,12 +1561,7 @@ int dm_resume(struct mapped_device *md)
if (r)
goto out;
down_write(&md->io_lock);
clear_bit(DMF_BLOCK_IO, &md->flags);
def = bio_list_get(&md->deferred);
__flush_deferred_io(md, def);
up_write(&md->io_lock);
dm_queue_flush(md, DM_WQ_FLUSH_DEFERRED, NULL);
unlock_fs(md);
@ -1520,7 +1580,7 @@ int dm_resume(struct mapped_device *md)
out:
dm_table_put(map);
up(&md->suspend_lock);
mutex_unlock(&md->suspend_lock);
return r;
}

34
fs/compat_ioctl.c
View File

@ -78,7 +78,6 @@
#include <linux/mii.h>
#include <linux/if_bonding.h>
#include <linux/watchdog.h>
#include <linux/dm-ioctl.h>
#include <linux/soundcard.h>
#include <linux/lp.h>
@ -1993,39 +1992,6 @@ COMPATIBLE_IOCTL(STOP_ARRAY_RO)
COMPATIBLE_IOCTL(RESTART_ARRAY_RW)
COMPATIBLE_IOCTL(GET_BITMAP_FILE)
ULONG_IOCTL(SET_BITMAP_FILE)
/* DM */
COMPATIBLE_IOCTL(DM_VERSION_32)
COMPATIBLE_IOCTL(DM_REMOVE_ALL_32)
COMPATIBLE_IOCTL(DM_LIST_DEVICES_32)
COMPATIBLE_IOCTL(DM_DEV_CREATE_32)
COMPATIBLE_IOCTL(DM_DEV_REMOVE_32)
COMPATIBLE_IOCTL(DM_DEV_RENAME_32)
COMPATIBLE_IOCTL(DM_DEV_SUSPEND_32)
COMPATIBLE_IOCTL(DM_DEV_STATUS_32)
COMPATIBLE_IOCTL(DM_DEV_WAIT_32)
COMPATIBLE_IOCTL(DM_TABLE_LOAD_32)
COMPATIBLE_IOCTL(DM_TABLE_CLEAR_32)
COMPATIBLE_IOCTL(DM_TABLE_DEPS_32)
COMPATIBLE_IOCTL(DM_TABLE_STATUS_32)
COMPATIBLE_IOCTL(DM_LIST_VERSIONS_32)
COMPATIBLE_IOCTL(DM_TARGET_MSG_32)
COMPATIBLE_IOCTL(DM_DEV_SET_GEOMETRY_32)
COMPATIBLE_IOCTL(DM_VERSION)
COMPATIBLE_IOCTL(DM_REMOVE_ALL)
COMPATIBLE_IOCTL(DM_LIST_DEVICES)
COMPATIBLE_IOCTL(DM_DEV_CREATE)
COMPATIBLE_IOCTL(DM_DEV_REMOVE)
COMPATIBLE_IOCTL(DM_DEV_RENAME)
COMPATIBLE_IOCTL(DM_DEV_SUSPEND)
COMPATIBLE_IOCTL(DM_DEV_STATUS)
COMPATIBLE_IOCTL(DM_DEV_WAIT)
COMPATIBLE_IOCTL(DM_TABLE_LOAD)
COMPATIBLE_IOCTL(DM_TABLE_CLEAR)
COMPATIBLE_IOCTL(DM_TABLE_DEPS)
COMPATIBLE_IOCTL(DM_TABLE_STATUS)
COMPATIBLE_IOCTL(DM_LIST_VERSIONS)
COMPATIBLE_IOCTL(DM_TARGET_MSG)
COMPATIBLE_IOCTL(DM_DEV_SET_GEOMETRY)
/* Big K */
COMPATIBLE_IOCTL(PIO_FONT)
COMPATIBLE_IOCTL(GIO_FONT)

18
include/linux/device-mapper.h
View File

@ -110,15 +110,15 @@ struct target_type {
};
struct io_restrictions {
unsigned int max_sectors;
unsigned short max_phys_segments;
unsigned short max_hw_segments;
unsigned short hardsect_size;
unsigned int max_segment_size;
unsigned int max_hw_sectors;
unsigned long seg_boundary_mask;
unsigned long bounce_pfn;
unsigned char no_cluster; /* inverted so that 0 is default */
unsigned long bounce_pfn;
unsigned long seg_boundary_mask;
unsigned max_hw_sectors;
unsigned max_sectors;
unsigned max_segment_size;
unsigned short hardsect_size;
unsigned short max_hw_segments;
unsigned short max_phys_segments;
unsigned char no_cluster; /* inverted so that 0 is default */
};
struct dm_target {

34
include/linux/dm-ioctl.h
View File

@ -232,36 +232,6 @@ enum {
DM_DEV_SET_GEOMETRY_CMD
};
/*
* The dm_ioctl struct passed into the ioctl is just the header
* on a larger chunk of memory. On x86-64 and other
* architectures the dm-ioctl struct will be padded to an 8 byte
* boundary so the size will be different, which would change the
* ioctl code - yes I really messed up. This hack forces these
* architectures to have the correct ioctl code.
*/
#ifdef CONFIG_COMPAT
typedef char ioctl_struct[308];
#define DM_VERSION_32 _IOWR(DM_IOCTL, DM_VERSION_CMD, ioctl_struct)
#define DM_REMOVE_ALL_32 _IOWR(DM_IOCTL, DM_REMOVE_ALL_CMD, ioctl_struct)
#define DM_LIST_DEVICES_32 _IOWR(DM_IOCTL, DM_LIST_DEVICES_CMD, ioctl_struct)
#define DM_DEV_CREATE_32 _IOWR(DM_IOCTL, DM_DEV_CREATE_CMD, ioctl_struct)
#define DM_DEV_REMOVE_32 _IOWR(DM_IOCTL, DM_DEV_REMOVE_CMD, ioctl_struct)
#define DM_DEV_RENAME_32 _IOWR(DM_IOCTL, DM_DEV_RENAME_CMD, ioctl_struct)
#define DM_DEV_SUSPEND_32 _IOWR(DM_IOCTL, DM_DEV_SUSPEND_CMD, ioctl_struct)
#define DM_DEV_STATUS_32 _IOWR(DM_IOCTL, DM_DEV_STATUS_CMD, ioctl_struct)
#define DM_DEV_WAIT_32 _IOWR(DM_IOCTL, DM_DEV_WAIT_CMD, ioctl_struct)
#define DM_TABLE_LOAD_32 _IOWR(DM_IOCTL, DM_TABLE_LOAD_CMD, ioctl_struct)
#define DM_TABLE_CLEAR_32 _IOWR(DM_IOCTL, DM_TABLE_CLEAR_CMD, ioctl_struct)
#define DM_TABLE_DEPS_32 _IOWR(DM_IOCTL, DM_TABLE_DEPS_CMD, ioctl_struct)
#define DM_TABLE_STATUS_32 _IOWR(DM_IOCTL, DM_TABLE_STATUS_CMD, ioctl_struct)
#define DM_LIST_VERSIONS_32 _IOWR(DM_IOCTL, DM_LIST_VERSIONS_CMD, ioctl_struct)
#define DM_TARGET_MSG_32 _IOWR(DM_IOCTL, DM_TARGET_MSG_CMD, ioctl_struct)
#define DM_DEV_SET_GEOMETRY_32 _IOWR(DM_IOCTL, DM_DEV_SET_GEOMETRY_CMD, ioctl_struct)
#endif
#define DM_IOCTL 0xfd
#define DM_VERSION _IOWR(DM_IOCTL, DM_VERSION_CMD, struct dm_ioctl)
@ -286,9 +256,9 @@ typedef char ioctl_struct[308];
#define DM_DEV_SET_GEOMETRY _IOWR(DM_IOCTL, DM_DEV_SET_GEOMETRY_CMD, struct dm_ioctl)
#define DM_VERSION_MAJOR 4
#define DM_VERSION_MINOR 12
#define DM_VERSION_MINOR 13
#define DM_VERSION_PATCHLEVEL 0
#define DM_VERSION_EXTRA "-ioctl (2007-10-02)"
#define DM_VERSION_EXTRA "-ioctl (2007-10-18)"
/* Status bits */
#define DM_READONLY_FLAG (1 << 0) /* In/Out */