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path: root/drivers/md/dm.c
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Diffstat (limited to 'drivers/md/dm.c')
-rw-r--r--drivers/md/dm.c200
1 files changed, 142 insertions, 58 deletions
diff --git a/drivers/md/dm.c b/drivers/md/dm.c
index 788ba96a625..424f7b048c3 100644
--- a/drivers/md/dm.c
+++ b/drivers/md/dm.c
@@ -6,7 +6,6 @@
*/
#include "dm.h"
-#include "dm-bio-list.h"
#include "dm-uevent.h"
#include <linux/init.h>
@@ -89,12 +88,13 @@ union map_info *dm_get_mapinfo(struct bio *bio)
/*
* 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.
@@ -124,6 +124,11 @@ struct mapped_device {
spinlock_t deferred_lock;
/*
+ * An error from the barrier request currently being processed.
+ */
+ int barrier_error;
+
+ /*
* Processing queue (flush/barriers)
*/
struct workqueue_struct *wq;
@@ -424,6 +429,10 @@ static void end_io_acct(struct dm_io *io)
part_stat_add(cpu, &dm_disk(md)->part0, ticks[rw], duration);
part_stat_unlock();
+ /*
+ * 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);
@@ -435,21 +444,18 @@ static void end_io_acct(struct dm_io *io)
/*
* 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 */
}
/*
@@ -533,25 +539,35 @@ static void dec_pending(struct dm_io *io, int error)
*/
spin_lock_irqsave(&md->deferred_lock, flags);
if (__noflush_suspending(md))
- bio_list_add(&md->deferred, io->bio);
+ bio_list_add_head(&md->deferred, io->bio);
else
/* noflush suspend was interrupted. */
io->error = -EIO;
spin_unlock_irqrestore(&md->deferred_lock, flags);
}
- end_io_acct(io);
-
io_error = io->error;
bio = io->bio;
- free_io(md, io);
+ if (bio_barrier(bio)) {
+ /*
+ * 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
+ */
+ md->barrier_error = io_error;
+ end_io_acct(io);
+ } else {
+ end_io_acct(io);
- if (io_error != DM_ENDIO_REQUEUE) {
- trace_block_bio_complete(md->queue, bio);
+ if (io_error != DM_ENDIO_REQUEUE) {
+ trace_block_bio_complete(md->queue, bio);
- bio_endio(bio, io_error);
+ bio_endio(bio, io_error);
+ }
}
+
+ free_io(md, io);
}
}
@@ -693,13 +709,19 @@ static struct bio *split_bvec(struct bio *bio, sector_t sector,
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);
+ bio_integrity_trim(clone,
+ bio_sector_offset(bio, idx, offset), len);
+ }
+
return clone;
}
@@ -714,6 +736,7 @@ static struct bio *clone_bio(struct bio *bio, sector_t sector,
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;
@@ -721,6 +744,14 @@ static struct bio *clone_bio(struct bio *bio, sector_t sector,
clone->bi_size = to_bytes(len);
clone->bi_flags &= ~(1 << BIO_SEG_VALID);
+ if (bio_integrity(bio)) {
+ bio_integrity_clone(clone, bio, GFP_NOIO);
+
+ if (idx != bio->bi_idx || clone->bi_size < bio->bi_size)
+ bio_integrity_trim(clone,
+ bio_sector_offset(bio, idx, 0), len);
+ }
+
return clone;
}
@@ -834,14 +865,13 @@ static void __split_and_process_bio(struct mapped_device *md, struct bio *bio)
ci.map = dm_get_table(md);
if (unlikely(!ci.map)) {
- bio_io_error(bio);
- return;
- }
- if (unlikely(bio_barrier(bio) && !dm_table_barrier_ok(ci.map))) {
- dm_table_put(ci.map);
- bio_endio(bio, -EOPNOTSUPP);
+ if (!bio_barrier(bio))
+ bio_io_error(bio);
+ else
+ md->barrier_error = -EIO;
return;
}
+
ci.md = md;
ci.bio = bio;
ci.io = alloc_io(md);
@@ -918,7 +948,6 @@ out:
*/
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;
@@ -931,34 +960,27 @@ static int dm_request(struct request_queue *q, struct bio *bio)
part_stat_unlock();
/*
- * If we're suspended we have to queue
- * this io for later.
+ * If we're suspended or the thread is processing barriers
+ * we have to queue this io for later.
*/
- while (test_bit(DMF_BLOCK_IO, &md->flags)) {
+ if (unlikely(test_bit(DMF_QUEUE_IO_TO_THREAD, &md->flags)) ||
+ unlikely(bio_barrier(bio))) {
up_read(&md->io_lock);
- if (bio_rw(bio) != READA)
- r = queue_io(md, bio);
+ if (unlikely(test_bit(DMF_BLOCK_IO_FOR_SUSPEND, &md->flags)) &&
+ bio_rw(bio) == READA) {
+ bio_io_error(bio);
+ return 0;
+ }
- if (r <= 0)
- goto out_req;
+ queue_io(md, bio);
- /*
- * We're in a while loop, because someone could suspend
- * before we get to the following read lock.
- */
- down_read(&md->io_lock);
+ return 0;
}
__split_and_process_bio(md, bio);
up_read(&md->io_lock);
return 0;
-
-out_req:
- if (r < 0)
- bio_io_error(bio);
-
- return 0;
}
static void dm_unplug_all(struct request_queue *q)
@@ -978,7 +1000,7 @@ static int dm_any_congested(void *congested_data, int bdi_bits)
struct mapped_device *md = congested_data;
struct dm_table *map;
- if (!test_bit(DMF_BLOCK_IO, &md->flags)) {
+ if (!test_bit(DMF_BLOCK_IO_FOR_SUSPEND, &md->flags)) {
map = dm_get_table(md);
if (map) {
r = dm_table_any_congested(map, bdi_bits);
@@ -1193,6 +1215,7 @@ static void free_dev(struct mapped_device *md)
mempool_destroy(md->tio_pool);
mempool_destroy(md->io_pool);
bioset_free(md->bs);
+ blk_integrity_unregister(md->disk);
del_gendisk(md->disk);
free_minor(minor);
@@ -1406,6 +1429,36 @@ static int dm_wait_for_completion(struct mapped_device *md, int interruptible)
return r;
}
+static int dm_flush(struct mapped_device *md)
+{
+ dm_wait_for_completion(md, TASK_UNINTERRUPTIBLE);
+ return 0;
+}
+
+static void process_barrier(struct mapped_device *md, struct bio *bio)
+{
+ int error = dm_flush(md);
+
+ if (unlikely(error)) {
+ bio_endio(bio, error);
+ return;
+ }
+ if (bio_empty_barrier(bio)) {
+ bio_endio(bio, 0);
+ return;
+ }
+
+ __split_and_process_bio(md, bio);
+
+ error = dm_flush(md);
+
+ if (!error && md->barrier_error)
+ error = md->barrier_error;
+
+ if (md->barrier_error != DM_ENDIO_REQUEUE)
+ bio_endio(bio, error);
+}
+
/*
* Process the deferred bios
*/
@@ -1417,25 +1470,34 @@ static void dm_wq_work(struct work_struct *work)
down_write(&md->io_lock);
-next_bio:
- spin_lock_irq(&md->deferred_lock);
- c = bio_list_pop(&md->deferred);
- spin_unlock_irq(&md->deferred_lock);
+ 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) {
- __split_and_process_bio(md, c);
- goto next_bio;
- }
+ if (!c) {
+ clear_bit(DMF_QUEUE_IO_TO_THREAD, &md->flags);
+ break;
+ }
- clear_bit(DMF_BLOCK_IO, &md->flags);
+ up_write(&md->io_lock);
+
+ if (bio_barrier(c))
+ process_barrier(md, c);
+ else
+ __split_and_process_bio(md, c);
+
+ down_write(&md->io_lock);
+ }
up_write(&md->io_lock);
}
static void dm_queue_flush(struct mapped_device *md)
{
+ clear_bit(DMF_BLOCK_IO_FOR_SUSPEND, &md->flags);
+ smp_mb__after_clear_bit();
queue_work(md->wq, &md->work);
- flush_workqueue(md->wq);
}
/*
@@ -1553,20 +1615,36 @@ int dm_suspend(struct mapped_device *md, unsigned suspend_flags)
}
/*
- * 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);
-
+ set_bit(DMF_BLOCK_IO_FOR_SUSPEND, &md->flags);
+ set_bit(DMF_QUEUE_IO_TO_THREAD, &md->flags);
up_write(&md->io_lock);
+ flush_workqueue(md->wq);
+
/*
- * 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, TASK_INTERRUPTIBLE);
down_write(&md->io_lock);
-
if (noflush)
clear_bit(DMF_NOFLUSH_SUSPENDING, &md->flags);
up_write(&md->io_lock);
@@ -1579,6 +1657,12 @@ int dm_suspend(struct mapped_device *md, unsigned suspend_flags)
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);