/*
* Copyright (C) 2001, 2002 Sistina Software (UK) Limited.
- * Copyright (C) 2004-2006 Red Hat, Inc. All rights reserved.
+ * Copyright (C) 2004-2008 Red Hat, Inc. All rights reserved.
*
* This file is released under the GPL.
*/
#include "dm.h"
-#include "dm-bio-list.h"
#include "dm-uevent.h"
#include <linux/init.h>
#include <linux/slab.h>
#include <linux/idr.h>
#include <linux/hdreg.h>
-#include <linux/blktrace_api.h>
-#include <linux/smp_lock.h>
+
+#include <trace/events/block.h>
#define DM_MSG_PREFIX "core"
+/*
+ * Cookies are numeric values sent with CHANGE and REMOVE
+ * uevents while resuming, removing or renaming the device.
+ */
+#define DM_COOKIE_ENV_VAR_NAME "DM_COOKIE"
+#define DM_COOKIE_LENGTH 24
+
static const char *_name = DM_NAME;
static unsigned int major = 0;
static DEFINE_SPINLOCK(_minor_lock);
/*
+ * For bio-based dm.
* One of these is allocated per bio.
*/
struct dm_io {
};
/*
+ * For bio-based dm.
* One of these is allocated per target within a bio. Hopefully
* this will be simplified out one day.
*/
union map_info info;
};
+/*
+ * For request-based dm.
+ * One of these is allocated per request.
+ */
+struct dm_rq_target_io {
+ struct mapped_device *md;
+ struct dm_target *ti;
+ struct request *orig, clone;
+ int error;
+ union map_info info;
+};
+
+/*
+ * For request-based dm.
+ * One of these is allocated per bio.
+ */
+struct dm_rq_clone_bio_info {
+ struct bio *orig;
+ struct dm_rq_target_io *tio;
+};
+
union map_info *dm_get_mapinfo(struct bio *bio)
{
if (bio && bio->bi_private)
return NULL;
}
+union map_info *dm_get_rq_mapinfo(struct request *rq)
+{
+ if (rq && rq->end_io_data)
+ return &((struct dm_rq_target_io *)rq->end_io_data)->info;
+ return NULL;
+}
+EXPORT_SYMBOL_GPL(dm_get_rq_mapinfo);
+
#define MINOR_ALLOCED ((void *)-1)
/*
* Bits for the md->flags field.
*/
-#define DMF_BLOCK_IO 0
+#define DMF_BLOCK_IO_FOR_SUSPEND 0
#define DMF_SUSPENDED 1
#define DMF_FROZEN 2
#define DMF_FREEING 3
#define DMF_DELETING 4
#define DMF_NOFLUSH_SUSPENDING 5
+#define DMF_QUEUE_IO_TO_THREAD 6
/*
* 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 mutex suspend_lock;
- spinlock_t pushback_lock;
rwlock_t map_lock;
atomic_t holders;
atomic_t open_count;
*/
atomic_t pending;
wait_queue_head_t wait;
+ struct work_struct work;
struct bio_list deferred;
- struct bio_list pushback;
+ spinlock_t deferred_lock;
+
+ /*
+ * An error from the barrier request currently being processed.
+ */
+ int barrier_error;
/*
* Processing queue (flush/barriers)
* freeze/thaw support require holding onto a super block
*/
struct super_block *frozen_sb;
- struct block_device *suspended_bdev;
+ struct block_device *bdev;
/* forced geometry settings */
struct hd_geometry geometry;
+
+ /* marker of flush suspend for request-based dm */
+ struct request suspend_rq;
+
+ /* For saving the address of __make_request for request based dm */
+ make_request_fn *saved_make_request_fn;
+
+ /* sysfs handle */
+ struct kobject kobj;
+
+ /* zero-length barrier that will be cloned and submitted to targets */
+ struct bio barrier_bio;
+};
+
+/*
+ * For mempools pre-allocation at the table loading time.
+ */
+struct dm_md_mempools {
+ mempool_t *io_pool;
+ mempool_t *tio_pool;
+ struct bio_set *bs;
};
#define MIN_IOS 256
static struct kmem_cache *_io_cache;
static struct kmem_cache *_tio_cache;
+static struct kmem_cache *_rq_tio_cache;
+static struct kmem_cache *_rq_bio_info_cache;
static int __init local_init(void)
{
- int r;
+ int r = -ENOMEM;
/* allocate a slab for the dm_ios */
_io_cache = KMEM_CACHE(dm_io, 0);
if (!_io_cache)
- return -ENOMEM;
+ return r;
/* allocate a slab for the target ios */
_tio_cache = KMEM_CACHE(dm_target_io, 0);
- if (!_tio_cache) {
- kmem_cache_destroy(_io_cache);
- return -ENOMEM;
- }
+ if (!_tio_cache)
+ goto out_free_io_cache;
+
+ _rq_tio_cache = KMEM_CACHE(dm_rq_target_io, 0);
+ if (!_rq_tio_cache)
+ goto out_free_tio_cache;
+
+ _rq_bio_info_cache = KMEM_CACHE(dm_rq_clone_bio_info, 0);
+ if (!_rq_bio_info_cache)
+ goto out_free_rq_tio_cache;
r = dm_uevent_init();
- if (r) {
- kmem_cache_destroy(_tio_cache);
- kmem_cache_destroy(_io_cache);
- return r;
- }
+ if (r)
+ goto out_free_rq_bio_info_cache;
_major = major;
r = register_blkdev(_major, _name);
- if (r < 0) {
- kmem_cache_destroy(_tio_cache);
- kmem_cache_destroy(_io_cache);
- dm_uevent_exit();
- return r;
- }
+ if (r < 0)
+ goto out_uevent_exit;
if (!_major)
_major = r;
return 0;
+
+out_uevent_exit:
+ dm_uevent_exit();
+out_free_rq_bio_info_cache:
+ kmem_cache_destroy(_rq_bio_info_cache);
+out_free_rq_tio_cache:
+ kmem_cache_destroy(_rq_tio_cache);
+out_free_tio_cache:
+ kmem_cache_destroy(_tio_cache);
+out_free_io_cache:
+ kmem_cache_destroy(_io_cache);
+
+ return r;
}
static void local_exit(void)
{
+ kmem_cache_destroy(_rq_bio_info_cache);
+ kmem_cache_destroy(_rq_tio_cache);
kmem_cache_destroy(_tio_cache);
kmem_cache_destroy(_io_cache);
unregister_blkdev(_major, _name);
/*
* Block device functions
*/
-static int dm_blk_open(struct inode *inode, struct file *file)
+static int dm_blk_open(struct block_device *bdev, fmode_t mode)
{
struct mapped_device *md;
spin_lock(&_minor_lock);
- md = inode->i_bdev->bd_disk->private_data;
+ md = bdev->bd_disk->private_data;
if (!md)
goto out;
return md ? 0 : -ENXIO;
}
-static int dm_blk_close(struct inode *inode, struct file *file)
+static int dm_blk_close(struct gendisk *disk, fmode_t mode)
{
- struct mapped_device *md;
-
- md = inode->i_bdev->bd_disk->private_data;
+ struct mapped_device *md = disk->private_data;
atomic_dec(&md->open_count);
dm_put(md);
return 0;
return dm_get_geometry(md, geo);
}
-static int dm_blk_ioctl(struct inode *inode, struct file *file,
+static int dm_blk_ioctl(struct block_device *bdev, fmode_t mode,
unsigned int cmd, unsigned long arg)
{
- struct mapped_device *md;
- struct dm_table *map;
+ struct mapped_device *md = bdev->bd_disk->private_data;
+ struct dm_table *map = dm_get_table(md);
struct dm_target *tgt;
int r = -ENOTTY;
- /* We don't really need this lock, but we do need 'inode'. */
- unlock_kernel();
-
- md = inode->i_bdev->bd_disk->private_data;
-
- map = dm_get_table(md);
-
if (!map || !dm_table_get_size(map))
goto out;
}
if (tgt->type->ioctl)
- r = tgt->type->ioctl(tgt, inode, file, cmd, arg);
+ r = tgt->type->ioctl(tgt, cmd, arg);
out:
dm_table_put(map);
- lock_kernel();
return r;
}
mempool_free(io, md->io_pool);
}
-static struct dm_target_io *alloc_tio(struct mapped_device *md)
+static void free_tio(struct mapped_device *md, struct dm_target_io *tio)
+{
+ mempool_free(tio, md->tio_pool);
+}
+
+static struct dm_rq_target_io *alloc_rq_tio(struct mapped_device *md)
{
- return mempool_alloc(md->tio_pool, GFP_NOIO);
+ return mempool_alloc(md->tio_pool, GFP_ATOMIC);
}
-static void free_tio(struct mapped_device *md, struct dm_target_io *tio)
+static void free_rq_tio(struct dm_rq_target_io *tio)
{
- mempool_free(tio, md->tio_pool);
+ mempool_free(tio, tio->md->tio_pool);
+}
+
+static struct dm_rq_clone_bio_info *alloc_bio_info(struct mapped_device *md)
+{
+ return mempool_alloc(md->io_pool, GFP_ATOMIC);
+}
+
+static void free_bio_info(struct dm_rq_clone_bio_info *info)
+{
+ mempool_free(info, info->tio->md->io_pool);
}
static void start_io_acct(struct dm_io *io)
io->start_time = jiffies;
- cpu = disk_stat_lock();
- disk_round_stats(cpu, dm_disk(md));
- disk_stat_unlock();
- dm_disk(md)->in_flight = atomic_inc_return(&md->pending);
+ cpu = part_stat_lock();
+ part_round_stats(cpu, &dm_disk(md)->part0);
+ part_stat_unlock();
+ dm_disk(md)->part0.in_flight = atomic_inc_return(&md->pending);
}
-static int end_io_acct(struct dm_io *io)
+static void end_io_acct(struct dm_io *io)
{
struct mapped_device *md = io->md;
struct bio *bio = io->bio;
int pending, cpu;
int rw = bio_data_dir(bio);
- cpu = disk_stat_lock();
- disk_round_stats(cpu, dm_disk(md));
- disk_stat_add(cpu, dm_disk(md), ticks[rw], duration);
- disk_stat_unlock();
+ cpu = part_stat_lock();
+ part_round_stats(cpu, &dm_disk(md)->part0);
+ part_stat_add(cpu, &dm_disk(md)->part0, ticks[rw], duration);
+ part_stat_unlock();
- dm_disk(md)->in_flight = pending = atomic_dec_return(&md->pending);
+ /*
+ * After this is decremented the bio must not be touched if it is
+ * a barrier.
+ */
+ dm_disk(md)->part0.in_flight = pending =
+ atomic_dec_return(&md->pending);
- return !pending;
+ /* nudge anyone waiting on suspend queue */
+ if (!pending)
+ wake_up(&md->wait);
}
/*
* Add the bio to the list of deferred io.
*/
-static int queue_io(struct mapped_device *md, struct bio *bio)
+static void queue_io(struct mapped_device *md, struct bio *bio)
{
down_write(&md->io_lock);
- if (!test_bit(DMF_BLOCK_IO, &md->flags)) {
- up_write(&md->io_lock);
- return 1;
- }
-
+ spin_lock_irq(&md->deferred_lock);
bio_list_add(&md->deferred, bio);
+ spin_unlock_irq(&md->deferred_lock);
+
+ if (!test_and_set_bit(DMF_QUEUE_IO_TO_THREAD, &md->flags))
+ queue_work(md->wq, &md->work);
up_write(&md->io_lock);
- return 0; /* deferred successfully */
}
/*
struct dm_table *dm_get_table(struct mapped_device *md)
{
struct dm_table *t;
+ unsigned long flags;
- read_lock(&md->map_lock);
+ read_lock_irqsave(&md->map_lock, flags);
t = md->map;
if (t)
dm_table_get(t);
- read_unlock(&md->map_lock);
+ read_unlock_irqrestore(&md->map_lock, flags);
return t;
}
static void dec_pending(struct dm_io *io, int error)
{
unsigned long flags;
+ int io_error;
+ struct bio *bio;
+ struct mapped_device *md = io->md;
/* Push-back supersedes any I/O errors */
- if (error && !(io->error > 0 && __noflush_suspending(io->md)))
+ if (error && !(io->error > 0 && __noflush_suspending(md)))
io->error = error;
if (atomic_dec_and_test(&io->io_count)) {
if (io->error == DM_ENDIO_REQUEUE) {
/*
* Target requested pushing back the I/O.
- * This must be handled before the sleeper on
- * suspend queue merges the pushback list.
*/
- spin_lock_irqsave(&io->md->pushback_lock, flags);
- if (__noflush_suspending(io->md))
- bio_list_add(&io->md->pushback, io->bio);
- else
+ spin_lock_irqsave(&md->deferred_lock, flags);
+ if (__noflush_suspending(md)) {
+ if (!bio_rw_flagged(io->bio, BIO_RW_BARRIER))
+ bio_list_add_head(&md->deferred,
+ io->bio);
+ } else
/* noflush suspend was interrupted. */
io->error = -EIO;
- spin_unlock_irqrestore(&io->md->pushback_lock, flags);
+ spin_unlock_irqrestore(&md->deferred_lock, flags);
}
- if (end_io_acct(io))
- /* nudge anyone waiting on suspend queue */
- wake_up(&io->md->wait);
+ io_error = io->error;
+ bio = io->bio;
+
+ if (bio_rw_flagged(bio, BIO_RW_BARRIER)) {
+ /*
+ * There can be just one barrier request so we use
+ * a per-device variable for error reporting.
+ * Note that you can't touch the bio after end_io_acct
+ */
+ if (!md->barrier_error && io_error != -EOPNOTSUPP)
+ md->barrier_error = io_error;
+ end_io_acct(io);
+ } else {
+ end_io_acct(io);
- if (io->error != DM_ENDIO_REQUEUE) {
- blk_add_trace_bio(io->md->queue, io->bio,
- BLK_TA_COMPLETE);
+ if (io_error != DM_ENDIO_REQUEUE) {
+ trace_block_bio_complete(md->queue, bio);
- bio_endio(io->bio, io->error);
+ bio_endio(bio, io_error);
+ }
}
- free_io(io->md, io);
+ free_io(md, io);
}
}
{
int r = 0;
struct dm_target_io *tio = bio->bi_private;
+ struct dm_io *io = tio->io;
struct mapped_device *md = tio->io->md;
dm_endio_fn endio = tio->ti->type->end_io;
}
}
- dec_pending(tio->io, error);
-
/*
* Store md for cleanup instead of tio which is about to get freed.
*/
bio->bi_private = md->bs;
- bio_put(bio);
free_tio(md, tio);
+ bio_put(bio);
+ dec_pending(io, error);
+}
+
+/*
+ * Partial completion handling for request-based dm
+ */
+static void end_clone_bio(struct bio *clone, int error)
+{
+ struct dm_rq_clone_bio_info *info = clone->bi_private;
+ struct dm_rq_target_io *tio = info->tio;
+ struct bio *bio = info->orig;
+ unsigned int nr_bytes = info->orig->bi_size;
+
+ bio_put(clone);
+
+ if (tio->error)
+ /*
+ * An error has already been detected on the request.
+ * Once error occurred, just let clone->end_io() handle
+ * the remainder.
+ */
+ return;
+ else if (error) {
+ /*
+ * Don't notice the error to the upper layer yet.
+ * The error handling decision is made by the target driver,
+ * when the request is completed.
+ */
+ tio->error = error;
+ return;
+ }
+
+ /*
+ * I/O for the bio successfully completed.
+ * Notice the data completion to the upper layer.
+ */
+
+ /*
+ * bios are processed from the head of the list.
+ * So the completing bio should always be rq->bio.
+ * If it's not, something wrong is happening.
+ */
+ if (tio->orig->bio != bio)
+ DMERR("bio completion is going in the middle of the request");
+
+ /*
+ * Update the original request.
+ * Do not use blk_end_request() here, because it may complete
+ * the original request before the clone, and break the ordering.
+ */
+ blk_update_request(tio->orig, 0, nr_bytes);
+}
+
+/*
+ * Don't touch any member of the md after calling this function because
+ * the md may be freed in dm_put() at the end of this function.
+ * Or do dm_get() before calling this function and dm_put() later.
+ */
+static void rq_completed(struct mapped_device *md, int run_queue)
+{
+ int wakeup_waiters = 0;
+ struct request_queue *q = md->queue;
+ unsigned long flags;
+
+ spin_lock_irqsave(q->queue_lock, flags);
+ if (!queue_in_flight(q))
+ wakeup_waiters = 1;
+ spin_unlock_irqrestore(q->queue_lock, flags);
+
+ /* nudge anyone waiting on suspend queue */
+ if (wakeup_waiters)
+ wake_up(&md->wait);
+
+ if (run_queue)
+ blk_run_queue(q);
+
+ /*
+ * dm_put() must be at the end of this function. See the comment above
+ */
+ dm_put(md);
+}
+
+static void free_rq_clone(struct request *clone)
+{
+ struct dm_rq_target_io *tio = clone->end_io_data;
+
+ blk_rq_unprep_clone(clone);
+ free_rq_tio(tio);
+}
+
+static void dm_unprep_request(struct request *rq)
+{
+ struct request *clone = rq->special;
+
+ rq->special = NULL;
+ rq->cmd_flags &= ~REQ_DONTPREP;
+
+ free_rq_clone(clone);
+}
+
+/*
+ * Requeue the original request of a clone.
+ */
+void dm_requeue_unmapped_request(struct request *clone)
+{
+ struct dm_rq_target_io *tio = clone->end_io_data;
+ struct mapped_device *md = tio->md;
+ struct request *rq = tio->orig;
+ struct request_queue *q = rq->q;
+ unsigned long flags;
+
+ dm_unprep_request(rq);
+
+ spin_lock_irqsave(q->queue_lock, flags);
+ if (elv_queue_empty(q))
+ blk_plug_device(q);
+ blk_requeue_request(q, rq);
+ spin_unlock_irqrestore(q->queue_lock, flags);
+
+ rq_completed(md, 0);
+}
+EXPORT_SYMBOL_GPL(dm_requeue_unmapped_request);
+
+static void __stop_queue(struct request_queue *q)
+{
+ blk_stop_queue(q);
+}
+
+static void stop_queue(struct request_queue *q)
+{
+ unsigned long flags;
+
+ spin_lock_irqsave(q->queue_lock, flags);
+ __stop_queue(q);
+ spin_unlock_irqrestore(q->queue_lock, flags);
+}
+
+static void __start_queue(struct request_queue *q)
+{
+ if (blk_queue_stopped(q))
+ blk_start_queue(q);
+}
+
+static void start_queue(struct request_queue *q)
+{
+ unsigned long flags;
+
+ spin_lock_irqsave(q->queue_lock, flags);
+ __start_queue(q);
+ spin_unlock_irqrestore(q->queue_lock, flags);
+}
+
+/*
+ * Complete the clone and the original request.
+ * Must be called without queue lock.
+ */
+static void dm_end_request(struct request *clone, int error)
+{
+ struct dm_rq_target_io *tio = clone->end_io_data;
+ struct mapped_device *md = tio->md;
+ struct request *rq = tio->orig;
+
+ if (blk_pc_request(rq)) {
+ rq->errors = clone->errors;
+ rq->resid_len = clone->resid_len;
+
+ if (rq->sense)
+ /*
+ * We are using the sense buffer of the original
+ * request.
+ * So setting the length of the sense data is enough.
+ */
+ rq->sense_len = clone->sense_len;
+ }
+
+ free_rq_clone(clone);
+
+ blk_end_request_all(rq, error);
+
+ rq_completed(md, 1);
+}
+
+/*
+ * Request completion handler for request-based dm
+ */
+static void dm_softirq_done(struct request *rq)
+{
+ struct request *clone = rq->completion_data;
+ struct dm_rq_target_io *tio = clone->end_io_data;
+ dm_request_endio_fn rq_end_io = tio->ti->type->rq_end_io;
+ int error = tio->error;
+
+ if (!(rq->cmd_flags & REQ_FAILED) && rq_end_io)
+ error = rq_end_io(tio->ti, clone, error, &tio->info);
+
+ if (error <= 0)
+ /* The target wants to complete the I/O */
+ dm_end_request(clone, error);
+ else if (error == DM_ENDIO_INCOMPLETE)
+ /* The target will handle the I/O */
+ return;
+ else if (error == DM_ENDIO_REQUEUE)
+ /* The target wants to requeue the I/O */
+ dm_requeue_unmapped_request(clone);
+ else {
+ DMWARN("unimplemented target endio return value: %d", error);
+ BUG();
+ }
+}
+
+/*
+ * Complete the clone and the original request with the error status
+ * through softirq context.
+ */
+static void dm_complete_request(struct request *clone, int error)
+{
+ struct dm_rq_target_io *tio = clone->end_io_data;
+ struct request *rq = tio->orig;
+
+ tio->error = error;
+ rq->completion_data = clone;
+ blk_complete_request(rq);
+}
+
+/*
+ * Complete the not-mapped clone and the original request with the error status
+ * through softirq context.
+ * Target's rq_end_io() function isn't called.
+ * This may be used when the target's map_rq() function fails.
+ */
+void dm_kill_unmapped_request(struct request *clone, int error)
+{
+ struct dm_rq_target_io *tio = clone->end_io_data;
+ struct request *rq = tio->orig;
+
+ rq->cmd_flags |= REQ_FAILED;
+ dm_complete_request(clone, error);
+}
+EXPORT_SYMBOL_GPL(dm_kill_unmapped_request);
+
+/*
+ * Called with the queue lock held
+ */
+static void end_clone_request(struct request *clone, int error)
+{
+ /*
+ * For just cleaning up the information of the queue in which
+ * the clone was dispatched.
+ * The clone is *NOT* freed actually here because it is alloced from
+ * dm own mempool and REQ_ALLOCED isn't set in clone->cmd_flags.
+ */
+ __blk_put_request(clone->q, clone);
+
+ /*
+ * Actual request completion is done in a softirq context which doesn't
+ * hold the queue lock. Otherwise, deadlock could occur because:
+ * - another request may be submitted by the upper level driver
+ * of the stacking during the completion
+ * - the submission which requires queue lock may be done
+ * against this queue
+ */
+ dm_complete_request(clone, error);
}
static sector_t max_io_len(struct mapped_device *md,
sector_t sector;
struct mapped_device *md;
- /*
- * Sanity checks.
- */
- BUG_ON(!clone->bi_size);
-
clone->bi_end_io = clone_endio;
clone->bi_private = tio;
if (r == DM_MAPIO_REMAPPED) {
/* the bio has been remapped so dispatch it */
- blk_add_trace_remap(bdev_get_queue(clone->bi_bdev), clone,
- tio->io->bio->bi_bdev->bd_dev,
- clone->bi_sector, sector);
+ trace_block_remap(bdev_get_queue(clone->bi_bdev), clone,
+ tio->io->bio->bi_bdev->bd_dev, sector);
generic_make_request(clone);
} else if (r < 0 || r == DM_MAPIO_REQUEUE) {
clone->bi_sector = sector;
clone->bi_bdev = bio->bi_bdev;
- clone->bi_rw = bio->bi_rw;
+ clone->bi_rw = bio->bi_rw & ~(1 << BIO_RW_BARRIER);
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;
+ clone->bi_flags |= 1 << BIO_CLONED;
+
+ if (bio_integrity(bio)) {
+ bio_integrity_clone(clone, bio, GFP_NOIO, bs);
+ bio_integrity_trim(clone,
+ bio_sector_offset(bio, idx, offset), len);
+ }
return clone;
}
clone = bio_alloc_bioset(GFP_NOIO, bio->bi_max_vecs, bs);
__bio_clone(clone, bio);
+ clone->bi_rw &= ~(1 << BIO_RW_BARRIER);
clone->bi_destructor = dm_bio_destructor;
clone->bi_sector = sector;
clone->bi_idx = idx;
clone->bi_size = to_bytes(len);
clone->bi_flags &= ~(1 << BIO_SEG_VALID);
+ if (bio_integrity(bio)) {
+ bio_integrity_clone(clone, bio, GFP_NOIO, bs);
+
+ if (idx != bio->bi_idx || clone->bi_size < bio->bi_size)
+ bio_integrity_trim(clone,
+ bio_sector_offset(bio, idx, 0), len);
+ }
+
return clone;
}
+static struct dm_target_io *alloc_tio(struct clone_info *ci,
+ struct dm_target *ti)
+{
+ struct dm_target_io *tio = mempool_alloc(ci->md->tio_pool, GFP_NOIO);
+
+ tio->io = ci->io;
+ tio->ti = ti;
+ memset(&tio->info, 0, sizeof(tio->info));
+
+ return tio;
+}
+
+static void __flush_target(struct clone_info *ci, struct dm_target *ti,
+ unsigned flush_nr)
+{
+ struct dm_target_io *tio = alloc_tio(ci, ti);
+ struct bio *clone;
+
+ tio->info.flush_request = flush_nr;
+
+ clone = bio_alloc_bioset(GFP_NOIO, 0, ci->md->bs);
+ __bio_clone(clone, ci->bio);
+ clone->bi_destructor = dm_bio_destructor;
+
+ __map_bio(ti, clone, tio);
+}
+
+static int __clone_and_map_empty_barrier(struct clone_info *ci)
+{
+ unsigned target_nr = 0, flush_nr;
+ struct dm_target *ti;
+
+ while ((ti = dm_table_get_target(ci->map, target_nr++)))
+ for (flush_nr = 0; flush_nr < ti->num_flush_requests;
+ flush_nr++)
+ __flush_target(ci, ti, flush_nr);
+
+ ci->sector_count = 0;
+
+ return 0;
+}
+
static int __clone_and_map(struct clone_info *ci)
{
struct bio *clone, *bio = ci->bio;
sector_t len = 0, max;
struct dm_target_io *tio;
+ if (unlikely(bio_empty_barrier(bio)))
+ return __clone_and_map_empty_barrier(ci);
+
ti = dm_table_find_target(ci->map, ci->sector);
if (!dm_target_is_valid(ti))
return -EIO;
/*
* Allocate a target io object.
*/
- tio = alloc_tio(ci->md);
- tio->io = ci->io;
- tio->ti = ti;
- memset(&tio->info, 0, sizeof(tio->info));
+ tio = alloc_tio(ci, ti);
if (ci->sector_count <= max) {
/*
max = max_io_len(ci->md, ci->sector, ti);
- tio = alloc_tio(ci->md);
- tio->io = ci->io;
- tio->ti = ti;
- memset(&tio->info, 0, sizeof(tio->info));
+ tio = alloc_tio(ci, ti);
}
len = min(remaining, max);
}
/*
- * Split the bio into several clones.
+ * Split the bio into several clones and submit it to targets.
*/
-static int __split_bio(struct mapped_device *md, struct bio *bio)
+static void __split_and_process_bio(struct mapped_device *md, struct bio *bio)
{
struct clone_info ci;
int error = 0;
ci.map = dm_get_table(md);
- if (unlikely(!ci.map))
- return -EIO;
+ if (unlikely(!ci.map)) {
+ if (!bio_rw_flagged(bio, BIO_RW_BARRIER))
+ bio_io_error(bio);
+ else
+ if (!md->barrier_error)
+ md->barrier_error = -EIO;
+ return;
+ }
ci.md = md;
ci.bio = bio;
ci.io->md = md;
ci.sector = bio->bi_sector;
ci.sector_count = bio_sectors(bio);
+ if (unlikely(bio_empty_barrier(bio)))
+ ci.sector_count = 1;
ci.idx = bio->bi_idx;
start_io_acct(ci.io);
/* drop the extra reference count */
dec_pending(ci.io, error);
dm_table_put(ci.map);
-
- return 0;
}
/*-----------------------------------------------------------------
* CRUD END
*/
if (max_size && ti->type->merge)
max_size = ti->type->merge(ti, bvm, biovec, max_size);
+ /*
+ * If the target doesn't support merge method and some of the devices
+ * provided their merge_bvec method (we know this by looking at
+ * queue_max_hw_sectors), then we can't allow bios with multiple vector
+ * entries. So always set max_size to 0, and the code below allows
+ * just one page.
+ */
+ else if (queue_max_hw_sectors(q) <= PAGE_SIZE >> 9)
+
+ max_size = 0;
out_table:
dm_table_put(map);
* The request function that just remaps the bio built up by
* dm_merge_bvec.
*/
-static int dm_request(struct request_queue *q, struct bio *bio)
+static int _dm_request(struct request_queue *q, struct bio *bio)
{
- int r = -EIO;
int rw = bio_data_dir(bio);
struct mapped_device *md = q->queuedata;
int cpu;
+ down_read(&md->io_lock);
+
+ cpu = part_stat_lock();
+ part_stat_inc(cpu, &dm_disk(md)->part0, ios[rw]);
+ part_stat_add(cpu, &dm_disk(md)->part0, sectors[rw], bio_sectors(bio));
+ part_stat_unlock();
+
/*
- * There is no use in forwarding any barrier request since we can't
- * guarantee it is (or can be) handled by the targets correctly.
+ * If we're suspended or the thread is processing barriers
+ * we have to queue this io for later.
*/
- if (unlikely(bio_barrier(bio))) {
+ if (unlikely(test_bit(DMF_QUEUE_IO_TO_THREAD, &md->flags)) ||
+ unlikely(bio_rw_flagged(bio, BIO_RW_BARRIER))) {
+ up_read(&md->io_lock);
+
+ if (unlikely(test_bit(DMF_BLOCK_IO_FOR_SUSPEND, &md->flags)) &&
+ bio_rw(bio) == READA) {
+ bio_io_error(bio);
+ return 0;
+ }
+
+ queue_io(md, bio);
+
+ return 0;
+ }
+
+ __split_and_process_bio(md, bio);
+ up_read(&md->io_lock);
+ return 0;
+}
+
+static int dm_make_request(struct request_queue *q, struct bio *bio)
+{
+ struct mapped_device *md = q->queuedata;
+
+ if (unlikely(bio_rw_flagged(bio, BIO_RW_BARRIER))) {
bio_endio(bio, -EOPNOTSUPP);
return 0;
}
- down_read(&md->io_lock);
+ return md->saved_make_request_fn(q, bio); /* call __make_request() */
+}
+
+static int dm_request_based(struct mapped_device *md)
+{
+ return blk_queue_stackable(md->queue);
+}
+
+static int dm_request(struct request_queue *q, struct bio *bio)
+{
+ struct mapped_device *md = q->queuedata;
- cpu = disk_stat_lock();
- disk_stat_inc(cpu, dm_disk(md), ios[rw]);
- disk_stat_add(cpu, dm_disk(md), sectors[rw], bio_sectors(bio));
- disk_stat_unlock();
+ if (dm_request_based(md))
+ return dm_make_request(q, bio);
+
+ return _dm_request(q, bio);
+}
+
+void dm_dispatch_request(struct request *rq)
+{
+ int r;
+
+ if (blk_queue_io_stat(rq->q))
+ rq->cmd_flags |= REQ_IO_STAT;
+
+ rq->start_time = jiffies;
+ r = blk_insert_cloned_request(rq->q, rq);
+ if (r)
+ dm_complete_request(rq, r);
+}
+EXPORT_SYMBOL_GPL(dm_dispatch_request);
+
+static void dm_rq_bio_destructor(struct bio *bio)
+{
+ struct dm_rq_clone_bio_info *info = bio->bi_private;
+ struct mapped_device *md = info->tio->md;
+
+ free_bio_info(info);
+ bio_free(bio, md->bs);
+}
+
+static int dm_rq_bio_constructor(struct bio *bio, struct bio *bio_orig,
+ void *data)
+{
+ struct dm_rq_target_io *tio = data;
+ struct mapped_device *md = tio->md;
+ struct dm_rq_clone_bio_info *info = alloc_bio_info(md);
+
+ if (!info)
+ return -ENOMEM;
+
+ info->orig = bio_orig;
+ info->tio = tio;
+ bio->bi_end_io = end_clone_bio;
+ bio->bi_private = info;
+ bio->bi_destructor = dm_rq_bio_destructor;
+
+ return 0;
+}
+
+static int setup_clone(struct request *clone, struct request *rq,
+ struct dm_rq_target_io *tio)
+{
+ int r = blk_rq_prep_clone(clone, rq, tio->md->bs, GFP_ATOMIC,
+ dm_rq_bio_constructor, tio);
+
+ if (r)
+ return r;
+
+ clone->cmd = rq->cmd;
+ clone->cmd_len = rq->cmd_len;
+ clone->sense = rq->sense;
+ clone->buffer = rq->buffer;
+ clone->end_io = end_clone_request;
+ clone->end_io_data = tio;
+
+ return 0;
+}
+
+static int dm_rq_flush_suspending(struct mapped_device *md)
+{
+ return !md->suspend_rq.special;
+}
+
+/*
+ * Called with the queue lock held.
+ */
+static int dm_prep_fn(struct request_queue *q, struct request *rq)
+{
+ struct mapped_device *md = q->queuedata;
+ struct dm_rq_target_io *tio;
+ struct request *clone;
+
+ if (unlikely(rq == &md->suspend_rq)) {
+ if (dm_rq_flush_suspending(md))
+ return BLKPREP_OK;
+ else
+ /* The flush suspend was interrupted */
+ return BLKPREP_KILL;
+ }
+
+ if (unlikely(rq->special)) {
+ DMWARN("Already has something in rq->special.");
+ return BLKPREP_KILL;
+ }
+
+ tio = alloc_rq_tio(md); /* Only one for each original request */
+ if (!tio)
+ /* -ENOMEM */
+ return BLKPREP_DEFER;
+
+ tio->md = md;
+ tio->ti = NULL;
+ tio->orig = rq;
+ tio->error = 0;
+ memset(&tio->info, 0, sizeof(tio->info));
+
+ clone = &tio->clone;
+ if (setup_clone(clone, rq, tio)) {
+ /* -ENOMEM */
+ free_rq_tio(tio);
+ return BLKPREP_DEFER;
+ }
+
+ rq->special = clone;
+ rq->cmd_flags |= REQ_DONTPREP;
+
+ return BLKPREP_OK;
+}
+
+static void map_request(struct dm_target *ti, struct request *rq,
+ struct mapped_device *md)
+{
+ int r;
+ struct request *clone = rq->special;
+ struct dm_rq_target_io *tio = clone->end_io_data;
/*
- * If we're suspended we have to queue
- * this io for later.
+ * Hold the md reference here for the in-flight I/O.
+ * We can't rely on the reference count by device opener,
+ * because the device may be closed during the request completion
+ * when all bios are completed.
+ * See the comment in rq_completed() too.
*/
- while (test_bit(DMF_BLOCK_IO, &md->flags)) {
- up_read(&md->io_lock);
+ dm_get(md);
- if (bio_rw(bio) != READA)
- r = queue_io(md, bio);
+ tio->ti = ti;
+ r = ti->type->map_rq(ti, clone, &tio->info);
+ switch (r) {
+ case DM_MAPIO_SUBMITTED:
+ /* The target has taken the I/O to submit by itself later */
+ break;
+ case DM_MAPIO_REMAPPED:
+ /* The target has remapped the I/O so dispatch it */
+ dm_dispatch_request(clone);
+ break;
+ case DM_MAPIO_REQUEUE:
+ /* The target wants to requeue the I/O */
+ dm_requeue_unmapped_request(clone);
+ break;
+ default:
+ if (r > 0) {
+ DMWARN("unimplemented target map return value: %d", r);
+ BUG();
+ }
- if (r <= 0)
- goto out_req;
+ /* The target wants to complete the I/O */
+ dm_kill_unmapped_request(clone, r);
+ break;
+ }
+}
- /*
- * We're in a while loop, because someone could suspend
- * before we get to the following read lock.
- */
- down_read(&md->io_lock);
+/*
+ * q->request_fn for request-based dm.
+ * Called with the queue lock held.
+ */
+static void dm_request_fn(struct request_queue *q)
+{
+ struct mapped_device *md = q->queuedata;
+ struct dm_table *map = dm_get_table(md);
+ struct dm_target *ti;
+ struct request *rq;
+
+ /*
+ * For noflush suspend, check blk_queue_stopped() to immediately
+ * quit I/O dispatching.
+ */
+ while (!blk_queue_plugged(q) && !blk_queue_stopped(q)) {
+ rq = blk_peek_request(q);
+ if (!rq)
+ goto plug_and_out;
+
+ if (unlikely(rq == &md->suspend_rq)) { /* Flush suspend maker */
+ if (queue_in_flight(q))
+ /* Not quiet yet. Wait more */
+ goto plug_and_out;
+
+ /* This device should be quiet now */
+ __stop_queue(q);
+ blk_start_request(rq);
+ __blk_end_request_all(rq, 0);
+ wake_up(&md->wait);
+ goto out;
+ }
+
+ ti = dm_table_find_target(map, blk_rq_pos(rq));
+ if (ti->type->busy && ti->type->busy(ti))
+ goto plug_and_out;
+
+ blk_start_request(rq);
+ spin_unlock(q->queue_lock);
+ map_request(ti, rq, md);
+ spin_lock_irq(q->queue_lock);
}
- r = __split_bio(md, bio);
- up_read(&md->io_lock);
+ goto out;
-out_req:
- if (r < 0)
- bio_io_error(bio);
+plug_and_out:
+ if (!elv_queue_empty(q))
+ /* Some requests still remain, retry later */
+ blk_plug_device(q);
- return 0;
+out:
+ dm_table_put(map);
+
+ return;
+}
+
+int dm_underlying_device_busy(struct request_queue *q)
+{
+ return blk_lld_busy(q);
+}
+EXPORT_SYMBOL_GPL(dm_underlying_device_busy);
+
+static int dm_lld_busy(struct request_queue *q)
+{
+ int r;
+ struct mapped_device *md = q->queuedata;
+ struct dm_table *map = dm_get_table(md);
+
+ if (!map || test_bit(DMF_BLOCK_IO_FOR_SUSPEND, &md->flags))
+ r = 1;
+ else
+ r = dm_table_any_busy_target(map);
+
+ dm_table_put(map);
+
+ return r;
}
static void dm_unplug_all(struct request_queue *q)
struct dm_table *map = dm_get_table(md);
if (map) {
+ if (dm_request_based(md))
+ generic_unplug_device(q);
+
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);
+ int r = bdi_bits;
+ struct mapped_device *md = congested_data;
+ struct dm_table *map;
- if (!map || test_bit(DMF_BLOCK_IO, &md->flags))
- r = bdi_bits;
- else
- r = dm_table_any_congested(map, bdi_bits);
+ if (!test_bit(DMF_BLOCK_IO_FOR_SUSPEND, &md->flags)) {
+ map = dm_get_table(md);
+ if (map) {
+ /*
+ * Request-based dm cares about only own queue for
+ * the query about congestion status of request_queue
+ */
+ if (dm_request_based(md))
+ r = md->queue->backing_dev_info.state &
+ bdi_bits;
+ else
+ r = dm_table_any_congested(map, bdi_bits);
+
+ dm_table_put(map);
+ }
+ }
- dm_table_put(map);
return r;
}
static struct block_device_operations dm_blk_dops;
+static void dm_wq_work(struct work_struct *work);
+
/*
* Allocate and initialise a blank device with a given minor.
*/
init_rwsem(&md->io_lock);
mutex_init(&md->suspend_lock);
- spin_lock_init(&md->pushback_lock);
+ spin_lock_init(&md->deferred_lock);
rwlock_init(&md->map_lock);
atomic_set(&md->holders, 1);
atomic_set(&md->open_count, 0);
INIT_LIST_HEAD(&md->uevent_list);
spin_lock_init(&md->uevent_lock);
- md->queue = blk_alloc_queue(GFP_KERNEL);
+ md->queue = blk_init_queue(dm_request_fn, NULL);
if (!md->queue)
goto bad_queue;
+ /*
+ * Request-based dm devices cannot be stacked on top of bio-based dm
+ * devices. The type of this dm device has not been decided yet,
+ * although we initialized the queue using blk_init_queue().
+ * The type is decided at the first table loading time.
+ * To prevent problematic device stacking, clear the queue flag
+ * for request stacking support until then.
+ *
+ * This queue is new, so no concurrency on the queue_flags.
+ */
+ queue_flag_clear_unlocked(QUEUE_FLAG_STACKABLE, md->queue);
+ md->saved_make_request_fn = md->queue->make_request_fn;
md->queue->queuedata = md;
md->queue->backing_dev_info.congested_fn = dm_any_congested;
md->queue->backing_dev_info.congested_data = md;
blk_queue_bounce_limit(md->queue, BLK_BOUNCE_ANY);
md->queue->unplug_fn = dm_unplug_all;
blk_queue_merge_bvec(md->queue, dm_merge_bvec);
-
- md->io_pool = mempool_create_slab_pool(MIN_IOS, _io_cache);
- if (!md->io_pool)
- goto bad_io_pool;
-
- md->tio_pool = mempool_create_slab_pool(MIN_IOS, _tio_cache);
- if (!md->tio_pool)
- goto bad_tio_pool;
-
- md->bs = bioset_create(16, 16);
- if (!md->bs)
- goto bad_no_bioset;
+ blk_queue_softirq_done(md->queue, dm_softirq_done);
+ blk_queue_prep_rq(md->queue, dm_prep_fn);
+ blk_queue_lld_busy(md->queue, dm_lld_busy);
md->disk = alloc_disk(1);
if (!md->disk)
atomic_set(&md->pending, 0);
init_waitqueue_head(&md->wait);
+ INIT_WORK(&md->work, dm_wq_work);
init_waitqueue_head(&md->eventq);
md->disk->major = _major;
if (!md->wq)
goto bad_thread;
+ md->bdev = bdget_disk(md->disk, 0);
+ if (!md->bdev)
+ goto bad_bdev;
+
/* Populate the mapping, nobody knows we exist yet */
spin_lock(&_minor_lock);
old_md = idr_replace(&_minor_idr, md, minor);
return md;
+bad_bdev:
+ destroy_workqueue(md->wq);
bad_thread:
put_disk(md->disk);
bad_disk:
- bioset_free(md->bs);
-bad_no_bioset:
- mempool_destroy(md->tio_pool);
-bad_tio_pool:
- mempool_destroy(md->io_pool);
-bad_io_pool:
blk_cleanup_queue(md->queue);
bad_queue:
free_minor(minor);
{
int minor = MINOR(disk_devt(md->disk));
- if (md->suspended_bdev) {
- unlock_fs(md);
- bdput(md->suspended_bdev);
- }
+ unlock_fs(md);
+ bdput(md->bdev);
destroy_workqueue(md->wq);
- mempool_destroy(md->tio_pool);
- mempool_destroy(md->io_pool);
- bioset_free(md->bs);
+ if (md->tio_pool)
+ mempool_destroy(md->tio_pool);
+ if (md->io_pool)
+ mempool_destroy(md->io_pool);
+ if (md->bs)
+ bioset_free(md->bs);
+ blk_integrity_unregister(md->disk);
del_gendisk(md->disk);
free_minor(minor);
kfree(md);
}
+static void __bind_mempools(struct mapped_device *md, struct dm_table *t)
+{
+ struct dm_md_mempools *p;
+
+ if (md->io_pool && md->tio_pool && md->bs)
+ /* the md already has necessary mempools */
+ goto out;
+
+ p = dm_table_get_md_mempools(t);
+ BUG_ON(!p || md->io_pool || md->tio_pool || md->bs);
+
+ md->io_pool = p->io_pool;
+ p->io_pool = NULL;
+ md->tio_pool = p->tio_pool;
+ p->tio_pool = NULL;
+ md->bs = p->bs;
+ p->bs = NULL;
+
+out:
+ /* mempool bind completed, now no need any mempools in the table */
+ dm_table_free_md_mempools(t);
+}
+
/*
* Bind a table to the device.
*/
list_splice_init(&md->uevent_list, &uevents);
spin_unlock_irqrestore(&md->uevent_lock, flags);
- dm_send_uevents(&uevents, &md->disk->dev.kobj);
+ dm_send_uevents(&uevents, &disk_to_dev(md->disk)->kobj);
atomic_inc(&md->event_nr);
wake_up(&md->eventq);
{
set_capacity(md->disk, size);
- mutex_lock(&md->suspended_bdev->bd_inode->i_mutex);
- i_size_write(md->suspended_bdev->bd_inode, (loff_t)size << SECTOR_SHIFT);
- mutex_unlock(&md->suspended_bdev->bd_inode->i_mutex);
+ mutex_lock(&md->bdev->bd_inode->i_mutex);
+ i_size_write(md->bdev->bd_inode, (loff_t)size << SECTOR_SHIFT);
+ mutex_unlock(&md->bdev->bd_inode->i_mutex);
}
-static int __bind(struct mapped_device *md, struct dm_table *t)
+static int __bind(struct mapped_device *md, struct dm_table *t,
+ struct queue_limits *limits)
{
struct request_queue *q = md->queue;
sector_t size;
+ unsigned long flags;
size = dm_table_get_size(t);
if (size != get_capacity(md->disk))
memset(&md->geometry, 0, sizeof(md->geometry));
- if (md->suspended_bdev)
- __set_size(md, size);
- if (size == 0)
+ __set_size(md, size);
+
+ if (!size) {
+ dm_table_destroy(t);
return 0;
+ }
- dm_table_get(t);
dm_table_event_callback(t, event_callback, md);
- write_lock(&md->map_lock);
+ /*
+ * The queue hasn't been stopped yet, if the old table type wasn't
+ * for request-based during suspension. So stop it to prevent
+ * I/O mapping before resume.
+ * This must be done before setting the queue restrictions,
+ * because request-based dm may be run just after the setting.
+ */
+ if (dm_table_request_based(t) && !blk_queue_stopped(q))
+ stop_queue(q);
+
+ __bind_mempools(md, t);
+
+ write_lock_irqsave(&md->map_lock, flags);
md->map = t;
- dm_table_set_restrictions(t, q);
- write_unlock(&md->map_lock);
+ dm_table_set_restrictions(t, q, limits);
+ write_unlock_irqrestore(&md->map_lock, flags);
return 0;
}
static void __unbind(struct mapped_device *md)
{
struct dm_table *map = md->map;
+ unsigned long flags;
if (!map)
return;
dm_table_event_callback(map, NULL, NULL);
- write_lock(&md->map_lock);
+ write_lock_irqsave(&md->map_lock, flags);
md->map = NULL;
- write_unlock(&md->map_lock);
- dm_table_put(map);
+ write_unlock_irqrestore(&md->map_lock, flags);
+ dm_table_destroy(map);
}
/*
if (!md)
return -ENXIO;
+ dm_sysfs_init(md);
+
*result = md;
return 0;
}
dm_table_presuspend_targets(map);
dm_table_postsuspend_targets(map);
}
- __unbind(md);
+ dm_sysfs_exit(md);
dm_table_put(map);
+ __unbind(md);
free_dev(md);
}
}
EXPORT_SYMBOL_GPL(dm_put);
-static int dm_wait_for_completion(struct mapped_device *md)
+static int dm_wait_for_completion(struct mapped_device *md, int interruptible)
{
int r = 0;
+ DECLARE_WAITQUEUE(wait, current);
+ struct request_queue *q = md->queue;
+ unsigned long flags;
+
+ dm_unplug_all(md->queue);
+
+ add_wait_queue(&md->wait, &wait);
while (1) {
- set_current_state(TASK_INTERRUPTIBLE);
+ set_current_state(interruptible);
smp_mb();
- if (!atomic_read(&md->pending))
+ if (dm_request_based(md)) {
+ spin_lock_irqsave(q->queue_lock, flags);
+ if (!queue_in_flight(q) && blk_queue_stopped(q)) {
+ spin_unlock_irqrestore(q->queue_lock, flags);
+ break;
+ }
+ spin_unlock_irqrestore(q->queue_lock, flags);
+ } else if (!atomic_read(&md->pending))
break;
- if (signal_pending(current)) {
+ if (interruptible == TASK_INTERRUPTIBLE &&
+ signal_pending(current)) {
r = -EINTR;
break;
}
}
set_current_state(TASK_RUNNING);
+ remove_wait_queue(&md->wait, &wait);
+
return r;
}
-/*
- * Process the deferred bios
- */
-static void __flush_deferred_io(struct mapped_device *md)
+static void dm_flush(struct mapped_device *md)
{
- struct bio *c;
+ dm_wait_for_completion(md, TASK_UNINTERRUPTIBLE);
- while ((c = bio_list_pop(&md->deferred))) {
- if (__split_bio(md, c))
- bio_io_error(c);
- }
+ bio_init(&md->barrier_bio);
+ md->barrier_bio.bi_bdev = md->bdev;
+ md->barrier_bio.bi_rw = WRITE_BARRIER;
+ __split_and_process_bio(md, &md->barrier_bio);
- clear_bit(DMF_BLOCK_IO, &md->flags);
+ dm_wait_for_completion(md, TASK_UNINTERRUPTIBLE);
}
-static void __merge_pushback_list(struct mapped_device *md)
+static void process_barrier(struct mapped_device *md, struct bio *bio)
{
- unsigned long flags;
+ md->barrier_error = 0;
+
+ dm_flush(md);
+
+ if (!bio_empty_barrier(bio)) {
+ __split_and_process_bio(md, bio);
+ dm_flush(md);
+ }
- 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 (md->barrier_error != DM_ENDIO_REQUEUE)
+ bio_endio(bio, md->barrier_error);
+ else {
+ spin_lock_irq(&md->deferred_lock);
+ bio_list_add_head(&md->deferred, bio);
+ spin_unlock_irq(&md->deferred_lock);
+ }
}
+/*
+ * Process the deferred bios
+ */
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;
+ struct mapped_device *md = container_of(work, struct mapped_device,
+ work);
+ struct bio *c;
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();
+
+ while (!test_bit(DMF_BLOCK_IO_FOR_SUSPEND, &md->flags)) {
+ spin_lock_irq(&md->deferred_lock);
+ c = bio_list_pop(&md->deferred);
+ spin_unlock_irq(&md->deferred_lock);
+
+ if (!c) {
+ clear_bit(DMF_QUEUE_IO_TO_THREAD, &md->flags);
+ break;
+ }
+
+ up_write(&md->io_lock);
+
+ if (dm_request_based(md))
+ generic_make_request(c);
+ else {
+ if (bio_rw_flagged(c, BIO_RW_BARRIER))
+ process_barrier(md, c);
+ else
+ __split_and_process_bio(md, c);
+ }
+
+ down_write(&md->io_lock);
}
- 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);
+ up_write(&md->io_lock);
}
-static void dm_queue_flush(struct mapped_device *md, int type, void *context)
+static void dm_queue_flush(struct mapped_device *md)
{
- struct dm_wq_req req;
-
- dm_wq_queue(md, type, context, &req);
- flush_workqueue(md->wq);
+ clear_bit(DMF_BLOCK_IO_FOR_SUSPEND, &md->flags);
+ smp_mb__after_clear_bit();
+ queue_work(md->wq, &md->work);
}
/*
*/
int dm_swap_table(struct mapped_device *md, struct dm_table *table)
{
+ struct queue_limits limits;
int r = -EINVAL;
mutex_lock(&md->suspend_lock);
if (!dm_suspended(md))
goto out;
- /* without bdev, the device size cannot be changed */
- if (!md->suspended_bdev)
- if (get_capacity(md->disk) != dm_table_get_size(table))
- goto out;
+ r = dm_calculate_queue_limits(table, &limits);
+ if (r)
+ goto out;
+
+ /* cannot change the device type, once a table is bound */
+ if (md->map &&
+ (dm_table_get_type(md->map) != dm_table_get_type(table))) {
+ DMWARN("can't change the device type after a table is bound");
+ goto out;
+ }
__unbind(md);
- r = __bind(md, table);
+ r = __bind(md, table, &limits);
out:
mutex_unlock(&md->suspend_lock);
return r;
}
+static void dm_rq_invalidate_suspend_marker(struct mapped_device *md)
+{
+ md->suspend_rq.special = (void *)0x1;
+}
+
+static void dm_rq_abort_suspend(struct mapped_device *md, int noflush)
+{
+ struct request_queue *q = md->queue;
+ unsigned long flags;
+
+ spin_lock_irqsave(q->queue_lock, flags);
+ if (!noflush)
+ dm_rq_invalidate_suspend_marker(md);
+ __start_queue(q);
+ spin_unlock_irqrestore(q->queue_lock, flags);
+}
+
+static void dm_rq_start_suspend(struct mapped_device *md, int noflush)
+{
+ struct request *rq = &md->suspend_rq;
+ struct request_queue *q = md->queue;
+
+ if (noflush)
+ stop_queue(q);
+ else {
+ blk_rq_init(q, rq);
+ blk_insert_request(q, rq, 0, NULL);
+ }
+}
+
+static int dm_rq_suspend_available(struct mapped_device *md, int noflush)
+{
+ int r = 1;
+ struct request *rq = &md->suspend_rq;
+ struct request_queue *q = md->queue;
+ unsigned long flags;
+
+ if (noflush)
+ return r;
+
+ /* The marker must be protected by queue lock if it is in use */
+ spin_lock_irqsave(q->queue_lock, flags);
+ if (unlikely(rq->ref_count)) {
+ /*
+ * This can happen, when the previous flush suspend was
+ * interrupted, the marker is still in the queue and
+ * this flush suspend has been invoked, because we don't
+ * remove the marker at the time of suspend interruption.
+ * We have only one marker per mapped_device, so we can't
+ * start another flush suspend while it is in use.
+ */
+ BUG_ON(!rq->special); /* The marker should be invalidated */
+ DMWARN("Invalidating the previous flush suspend is still in"
+ " progress. Please retry later.");
+ r = 0;
+ }
+ spin_unlock_irqrestore(q->queue_lock, flags);
+
+ return r;
+}
+
/*
* Functions to lock and unlock any filesystem running on the
* device.
WARN_ON(md->frozen_sb);
- md->frozen_sb = freeze_bdev(md->suspended_bdev);
+ md->frozen_sb = freeze_bdev(md->bdev);
if (IS_ERR(md->frozen_sb)) {
r = PTR_ERR(md->frozen_sb);
md->frozen_sb = NULL;
set_bit(DMF_FROZEN, &md->flags);
- /* don't bdput right now, we don't want the bdev
- * to go away while it is locked.
- */
return 0;
}
if (!test_bit(DMF_FROZEN, &md->flags))
return;
- thaw_bdev(md->suspended_bdev, md->frozen_sb);
+ thaw_bdev(md->bdev, md->frozen_sb);
md->frozen_sb = NULL;
clear_bit(DMF_FROZEN, &md->flags);
}
* dm_bind_table, dm_suspend must be called to flush any in
* flight bios and ensure that any further io gets deferred.
*/
+/*
+ * Suspend mechanism in request-based dm.
+ *
+ * After the suspend starts, further incoming requests are kept in
+ * the request_queue and deferred.
+ * Remaining requests in the request_queue at the start of suspend are flushed
+ * if it is flush suspend.
+ * The suspend completes when the following conditions have been satisfied,
+ * so wait for it:
+ * 1. q->in_flight is 0 (which means no in_flight request)
+ * 2. queue has been stopped (which means no request dispatching)
+ *
+ *
+ * Noflush suspend
+ * ---------------
+ * Noflush suspend doesn't need to dispatch remaining requests.
+ * So stop the queue immediately. Then, wait for all in_flight requests
+ * to be completed or requeued.
+ *
+ * To abort noflush suspend, start the queue.
+ *
+ *
+ * Flush suspend
+ * -------------
+ * Flush suspend needs to dispatch remaining requests. So stop the queue
+ * after the remaining requests are completed. (Requeued request must be also
+ * re-dispatched and completed. Until then, we can't stop the queue.)
+ *
+ * During flushing the remaining requests, further incoming requests are also
+ * inserted to the same queue. To distinguish which requests are to be
+ * flushed, we insert a marker request to the queue at the time of starting
+ * flush suspend, like a barrier.
+ * The dispatching is blocked when the marker is found on the top of the queue.
+ * And the queue is stopped when all in_flight requests are completed, since
+ * that means the remaining requests are completely flushed.
+ * Then, the marker is removed from the queue.
+ *
+ * To abort flush suspend, we also need to take care of the marker, not only
+ * starting the queue.
+ * We don't remove the marker forcibly from the queue since it's against
+ * the block-layer manner. Instead, we put a invalidated mark on the marker.
+ * When the invalidated marker is found on the top of the queue, it is
+ * immediately removed from the queue, so it doesn't block dispatching.
+ * Because we have only one marker per mapped_device, we can't start another
+ * flush suspend until the invalidated marker is removed from the queue.
+ * So fail and return with -EBUSY in such a case.
+ */
int dm_suspend(struct mapped_device *md, unsigned suspend_flags)
{
struct dm_table *map = NULL;
- DECLARE_WAITQUEUE(wait, current);
int r = 0;
int do_lockfs = suspend_flags & DM_SUSPEND_LOCKFS_FLAG ? 1 : 0;
int noflush = suspend_flags & DM_SUSPEND_NOFLUSH_FLAG ? 1 : 0;
goto out_unlock;
}
+ if (dm_request_based(md) && !dm_rq_suspend_available(md, noflush)) {
+ r = -EBUSY;
+ goto out_unlock;
+ }
+
map = dm_get_table(md);
/*
/* This does not get reverted if there's an error later. */
dm_table_presuspend_targets(map);
- /* bdget() can stall if the pending I/Os are not flushed */
- if (!noflush) {
- md->suspended_bdev = bdget_disk(md->disk, 0);
- if (!md->suspended_bdev) {
- DMWARN("bdget failed in dm_suspend");
- 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) {
- 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 (!noflush && do_lockfs) {
+ r = lock_fs(md);
+ if (r)
+ goto out;
}
/*
- * First we set the BLOCK_IO flag so no more ios will be mapped.
+ * Here we must make sure that no processes are submitting requests
+ * to target drivers i.e. no one may be executing
+ * __split_and_process_bio. This is called from dm_request and
+ * dm_wq_work.
+ *
+ * To get all processes out of __split_and_process_bio in dm_request,
+ * we take the write lock. To prevent any process from reentering
+ * __split_and_process_bio from dm_request, we set
+ * DMF_QUEUE_IO_TO_THREAD.
+ *
+ * To quiesce the thread (dm_wq_work), we set DMF_BLOCK_IO_FOR_SUSPEND
+ * and call flush_workqueue(md->wq). flush_workqueue will wait until
+ * dm_wq_work exits and DMF_BLOCK_IO_FOR_SUSPEND will prevent any
+ * further calls to __split_and_process_bio from dm_wq_work.
*/
down_write(&md->io_lock);
- set_bit(DMF_BLOCK_IO, &md->flags);
-
- add_wait_queue(&md->wait, &wait);
+ set_bit(DMF_BLOCK_IO_FOR_SUSPEND, &md->flags);
+ set_bit(DMF_QUEUE_IO_TO_THREAD, &md->flags);
up_write(&md->io_lock);
- /* unplug */
- if (map)
- dm_table_unplug_all(map);
+ flush_workqueue(md->wq);
+
+ if (dm_request_based(md))
+ dm_rq_start_suspend(md, noflush);
/*
- * Wait for the already-mapped ios to complete.
+ * At this point no more requests are entering target request routines.
+ * We call dm_wait_for_completion to wait for all existing requests
+ * to finish.
*/
- r = dm_wait_for_completion(md);
+ r = dm_wait_for_completion(md, TASK_INTERRUPTIBLE);
down_write(&md->io_lock);
- remove_wait_queue(&md->wait, &wait);
-
if (noflush)
- __merge_pushback_list(md);
+ clear_bit(DMF_NOFLUSH_SUSPENDING, &md->flags);
up_write(&md->io_lock);
/* were we interrupted ? */
if (r < 0) {
- dm_queue_flush(md, DM_WQ_FLUSH_DEFERRED, NULL);
+ dm_queue_flush(md);
+
+ if (dm_request_based(md))
+ dm_rq_abort_suspend(md, noflush);
unlock_fs(md);
goto out; /* pushback list is already flushed, so skip flush */
}
+ /*
+ * If dm_wait_for_completion returned 0, the device is completely
+ * quiescent now. There is no request-processing activity. All new
+ * requests are being added to md->deferred list.
+ */
+
dm_table_postsuspend_targets(map);
set_bit(DMF_SUSPENDED, &md->flags);
-flush_and_out:
- if (r && noflush)
- /*
- * Because there may be already I/Os in the pushback list,
- * flush them before return.
- */
- dm_queue_flush(md, DM_WQ_FLUSH_ALL, NULL);
-
out:
- if (r && md->suspended_bdev) {
- bdput(md->suspended_bdev);
- md->suspended_bdev = NULL;
- }
-
dm_table_put(map);
out_unlock:
if (r)
goto out;
- dm_queue_flush(md, DM_WQ_FLUSH_DEFERRED, NULL);
+ dm_queue_flush(md);
- unlock_fs(md);
+ /*
+ * Flushing deferred I/Os must be done after targets are resumed
+ * so that mapping of targets can work correctly.
+ * Request-based dm is queueing the deferred I/Os in its request_queue.
+ */
+ if (dm_request_based(md))
+ start_queue(md->queue);
- if (md->suspended_bdev) {
- bdput(md->suspended_bdev);
- md->suspended_bdev = NULL;
- }
+ unlock_fs(md);
clear_bit(DMF_SUSPENDED, &md->flags);
dm_table_unplug_all(map);
-
- dm_kobject_uevent(md);
-
r = 0;
-
out:
dm_table_put(map);
mutex_unlock(&md->suspend_lock);
/*-----------------------------------------------------------------
* Event notification.
*---------------------------------------------------------------*/
-void dm_kobject_uevent(struct mapped_device *md)
-{
- kobject_uevent(&md->disk->dev.kobj, KOBJ_CHANGE);
+void dm_kobject_uevent(struct mapped_device *md, enum kobject_action action,
+ unsigned cookie)
+{
+ char udev_cookie[DM_COOKIE_LENGTH];
+ char *envp[] = { udev_cookie, NULL };
+
+ if (!cookie)
+ kobject_uevent(&disk_to_dev(md->disk)->kobj, action);
+ else {
+ snprintf(udev_cookie, DM_COOKIE_LENGTH, "%s=%u",
+ DM_COOKIE_ENV_VAR_NAME, cookie);
+ kobject_uevent_env(&disk_to_dev(md->disk)->kobj, action, envp);
+ }
}
uint32_t dm_next_uevent_seq(struct mapped_device *md)
return md->disk;
}
+struct kobject *dm_kobject(struct mapped_device *md)
+{
+ return &md->kobj;
+}
+
+/*
+ * struct mapped_device should not be exported outside of dm.c
+ * so use this check to verify that kobj is part of md structure
+ */
+struct mapped_device *dm_get_from_kobject(struct kobject *kobj)
+{
+ struct mapped_device *md;
+
+ md = container_of(kobj, struct mapped_device, kobj);
+ if (&md->kobj != kobj)
+ return NULL;
+
+ if (test_bit(DMF_FREEING, &md->flags) ||
+ test_bit(DMF_DELETING, &md->flags))
+ return NULL;
+
+ dm_get(md);
+ return md;
+}
+
int dm_suspended(struct mapped_device *md)
{
return test_bit(DMF_SUSPENDED, &md->flags);
}
EXPORT_SYMBOL_GPL(dm_noflush_suspending);
+struct dm_md_mempools *dm_alloc_md_mempools(unsigned type)
+{
+ struct dm_md_mempools *pools = kmalloc(sizeof(*pools), GFP_KERNEL);
+
+ if (!pools)
+ return NULL;
+
+ pools->io_pool = (type == DM_TYPE_BIO_BASED) ?
+ mempool_create_slab_pool(MIN_IOS, _io_cache) :
+ mempool_create_slab_pool(MIN_IOS, _rq_bio_info_cache);
+ if (!pools->io_pool)
+ goto free_pools_and_out;
+
+ pools->tio_pool = (type == DM_TYPE_BIO_BASED) ?
+ mempool_create_slab_pool(MIN_IOS, _tio_cache) :
+ mempool_create_slab_pool(MIN_IOS, _rq_tio_cache);
+ if (!pools->tio_pool)
+ goto free_io_pool_and_out;
+
+ pools->bs = (type == DM_TYPE_BIO_BASED) ?
+ bioset_create(16, 0) : bioset_create(MIN_IOS, 0);
+ if (!pools->bs)
+ goto free_tio_pool_and_out;
+
+ return pools;
+
+free_tio_pool_and_out:
+ mempool_destroy(pools->tio_pool);
+
+free_io_pool_and_out:
+ mempool_destroy(pools->io_pool);
+
+free_pools_and_out:
+ kfree(pools);
+
+ return NULL;
+}
+
+void dm_free_md_mempools(struct dm_md_mempools *pools)
+{
+ if (!pools)
+ return;
+
+ if (pools->io_pool)
+ mempool_destroy(pools->io_pool);
+
+ if (pools->tio_pool)
+ mempool_destroy(pools->tio_pool);
+
+ if (pools->bs)
+ bioset_free(pools->bs);
+
+ kfree(pools);
+}
+
static struct block_device_operations dm_blk_dops = {
.open = dm_blk_open,
.release = dm_blk_close,
git://ftp.safe.ca / safe / jmp / linux-2.6 / blobdiff