diff options
| -rw-r--r-- | drivers/md/dm.c | 88 |
1 files changed, 68 insertions, 20 deletions
diff --git a/drivers/md/dm.c b/drivers/md/dm.c index db022e5f3912..8a994be035ba 100644 --- a/drivers/md/dm.c +++ b/drivers/md/dm.c @@ -125,6 +125,11 @@ 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; @@ -425,6 +430,10 @@ 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); @@ -531,25 +540,35 @@ 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); } } @@ -691,7 +710,7 @@ 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; @@ -718,6 +737,7 @@ 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; @@ -846,7 +866,10 @@ 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); + if (!bio_barrier(bio)) + bio_io_error(bio); + else + md->barrier_error = -EIO; return; } @@ -930,15 +953,6 @@ static int dm_request(struct request_queue *q, struct bio *bio) struct mapped_device *md = q->queuedata; int cpu; - /* - * 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 (unlikely(bio_barrier(bio))) { - bio_endio(bio, -EOPNOTSUPP); - return 0; - } - down_read(&md->io_lock); cpu = part_stat_lock(); @@ -950,7 +964,8 @@ static int dm_request(struct request_queue *q, struct bio *bio) * If we're suspended or the thread is processing barriers * we have to queue this io for later. */ - if (unlikely(test_bit(DMF_QUEUE_IO_TO_THREAD, &md->flags))) { + if (unlikely(test_bit(DMF_QUEUE_IO_TO_THREAD, &md->flags)) || + unlikely(bio_barrier(bio))) { up_read(&md->io_lock); if (unlikely(test_bit(DMF_BLOCK_IO_FOR_SUSPEND, &md->flags)) && @@ -1415,6 +1430,36 @@ 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 */ @@ -1438,7 +1483,10 @@ static void dm_wq_work(struct work_struct *work) up_write(&md->io_lock); - __split_and_process_bio(md, c); + if (bio_barrier(c)) + process_barrier(md, c); + else + __split_and_process_bio(md, c); down_write(&md->io_lock); } |