Process barrier request with payload in device-mapper.
Because mapping of device can be generic, device-mapper
cannot process barriers containing data directly.
To emulate the same effect of barrier, process bio
like normal request and subsequently inject to all mapped
targets zero-sized barrier (whilst incoming bios are queued).
Signed-off-by: Milan Broz <mbroz@xxxxxxxxxx>
---
drivers/md/dm.c | 24 ++++++++++++------------
1 files changed, 12 insertions(+), 12 deletions(-)
diff --git a/drivers/md/dm.c b/drivers/md/dm.c
index d2f7e0b..f3d1ee5 100644
--- a/drivers/md/dm.c
+++ b/drivers/md/dm.c
@@ -536,7 +536,7 @@ static int __noflush_suspending(struct mapped_device *md)
static void dec_pending(struct dm_io *io, int error)
{
unsigned long flags;
- int barrier = bio_empty_barrier(io->bio);
+ int barrier = bio_barrier(io->bio);
/* Push-back supersedes any I/O errors */
if (error && !(io->error > 0 && __noflush_suspending(io->md)))
@@ -708,6 +708,7 @@ 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 &= ~(1 << BIO_RW_BARRIER);
clone->bi_vcnt = 1;
clone->bi_size = to_bytes(len);
clone->bi_io_vec->bv_offset = offset;
@@ -734,6 +735,7 @@ static struct bio *clone_bio(struct bio *bio, sector_t sector,
clone->bi_vcnt = idx + bv_count;
clone->bi_size = to_bytes(len);
clone->bi_flags &= ~(1 << BIO_SEG_VALID);
+ clone->bi_rw &= ~(1 << BIO_RW_BARRIER);
return clone;
}
@@ -893,11 +895,15 @@ static int __split_bio(struct mapped_device *md, struct bio *bio)
start_io_acct(ci.io);
- if (unlikely(bio_empty_barrier(ci.bio)))
- error = __clone_and_map_barrier(&ci);
- else
- while (ci.sector_count && !error)
- error = __clone_and_map(&ci);
+ while (ci.sector_count && !error)
+ error = __clone_and_map(&ci);
+
+ /*
+ * Barrier with payload is converted to normal bio
+ * and subsequent zero-size barrier requests.
+ */
+ if (unlikely(bio_barrier(ci.bio)) && !error)
+ error = __clone_and_map_barrier(&ci);
/* drop the extra reference count */
dec_pending(ci.io, error);
@@ -1531,12 +1537,6 @@ static void __merge_pushback_list(struct mapped_device *md)
static void __request_barrier(struct mapped_device *md, struct bio *bio)
{
- /* Only barriers without payload are supported */
- if (bio->bi_size) {
- bio_endio(bio, -EOPNOTSUPP);
- return;
- }
-
smp_mb();
if (!test_bit(DMF_BLOCK_IO, &md->flags))
__submit_barrier(md, bio);
--
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