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dm: disable barriers

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This patch causes device-mapper to reject any barrier requests.  This is done
since most of the targets won't handle this correctly anyway.  So until the
situation improves it is better to reject these requests at the first place.
Since barrier requests won't get to the targets, the checks there can be
removed.

Cc: stable@kernel.org
Signed-off-by: Stefan Bader <shbader@de.ibm.com>
Signed-off-by: Alasdair G Kergon <agk@redhat.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This commit is contained in:
Stefan Bader 2007-07-12 17:28:33 +01:00 committed by Linus Torvalds
parent 943317efdb
commit 07a83c47cf
4 changed files with 9 additions and 12 deletions
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3
drivers/md/dm-crypt.c
View file

@ -941,9 +941,6 @@ static int crypt_map(struct dm_target *ti, struct bio *bio,
struct crypt_config *cc = ti->private;
struct dm_crypt_io *io;
if (bio_barrier(bio))
return -EOPNOTSUPP;
io = mempool_alloc(cc->io_pool, GFP_NOIO);
io->target = ti;
io->base_bio = bio;

3
drivers/md/dm-mpath.c
View file

@ -798,9 +798,6 @@ static int multipath_map(struct dm_target *ti, struct bio *bio,
struct dm_mpath_io *mpio;
struct multipath *m = (struct multipath *) ti->private;
if (bio_barrier(bio))
return -EOPNOTSUPP;
mpio = mempool_alloc(m->mpio_pool, GFP_NOIO);
dm_bio_record(&mpio->details, bio);

6
drivers/md/dm-snap.c
View file

@ -889,9 +889,6 @@ static int snapshot_map(struct dm_target *ti, struct bio *bio,
if (!s->valid)
return -EIO;
if (unlikely(bio_barrier(bio)))
return -EOPNOTSUPP;
/* FIXME: should only take write lock if we need
* to copy an exception */
down_write(&s->lock);
@ -1162,9 +1159,6 @@ static int origin_map(struct dm_target *ti, struct bio *bio,
struct dm_dev *dev = ti->private;
bio->bi_bdev = dev->bdev;
if (unlikely(bio_barrier(bio)))
return -EOPNOTSUPP;
/* Only tell snapshots if this is a write */
return (bio_rw(bio) == WRITE) ? do_origin(dev, bio) : DM_MAPIO_REMAPPED;
}

9
drivers/md/dm.c
View file

@ -800,6 +800,15 @@ static int dm_request(request_queue_t *q, struct bio *bio)
int rw = bio_data_dir(bio);
struct mapped_device *md = q->queuedata;
/*
* 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, bio->bi_size, -EOPNOTSUPP);
return 0;
}
down_read(&md->io_lock);
disk_stat_inc(dm_disk(md), ios[rw]);