dm: implement REQ_FLUSH/FUA support for bio-based dm
This patch converts bio-based dm to support REQ_FLUSH/FUA instead of
now deprecated REQ_HARDBARRIER.
* -EOPNOTSUPP handling logic dropped.
* Preflush is handled as before but postflush is dropped and replaced
with passing down REQ_FUA to member request_queues. This replaces
one array wide cache flush w/ member specific FUA writes.
* __split_and_process_bio() now calls __clone_and_map_flush() directly
for flushes and guarantees all FLUSH bio's going to targets are zero
` length.
* It's now guaranteed that all FLUSH bio's which are passed onto dm
targets are zero length. bio_empty_barrier() tests are replaced
with REQ_FLUSH tests.
* Empty WRITE_BARRIERs are replaced with WRITE_FLUSHes.
* Dropped unlikely() around REQ_FLUSH tests. Flushes are not unlikely
enough to be marked with unlikely().
* Block layer now filters out REQ_FLUSH/FUA bio's if the request_queue
doesn't support cache flushing. Advertise REQ_FLUSH | REQ_FUA
capability.
* Request based dm isn't converted yet. dm_init_request_based_queue()
resets flush support to 0 for now. To avoid disturbing request
based dm code, dm->flush_error is added for bio based dm while
requested based dm continues to use dm->barrier_error.
Lightly tested linear, stripe, raid1, snap and crypt targets. Please
proceed with caution as I'm not familiar with the code base.
Signed-off-by: Tejun Heo <tj@kernel.org>
Cc: dm-devel@redhat.com
Cc: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jens Axboe <jaxboe@fusionio.com>
diff --git a/drivers/md/dm-raid1.c b/drivers/md/dm-raid1.c
index 7c081bc..19a59b0 100644
--- a/drivers/md/dm-raid1.c
+++ b/drivers/md/dm-raid1.c
@@ -259,7 +259,7 @@
struct dm_io_region io[ms->nr_mirrors];
struct mirror *m;
struct dm_io_request io_req = {
- .bi_rw = WRITE_BARRIER,
+ .bi_rw = WRITE_FLUSH,
.mem.type = DM_IO_KMEM,
.mem.ptr.bvec = NULL,
.client = ms->io_client,
@@ -629,7 +629,7 @@
struct dm_io_region io[ms->nr_mirrors], *dest = io;
struct mirror *m;
struct dm_io_request io_req = {
- .bi_rw = WRITE | (bio->bi_rw & WRITE_BARRIER),
+ .bi_rw = WRITE | (bio->bi_rw & WRITE_FLUSH_FUA),
.mem.type = DM_IO_BVEC,
.mem.ptr.bvec = bio->bi_io_vec + bio->bi_idx,
.notify.fn = write_callback,
@@ -670,7 +670,7 @@
bio_list_init(&requeue);
while ((bio = bio_list_pop(writes))) {
- if (unlikely(bio_empty_barrier(bio))) {
+ if (bio->bi_rw & REQ_FLUSH) {
bio_list_add(&sync, bio);
continue;
}
@@ -1203,7 +1203,7 @@
* We need to dec pending if this was a write.
*/
if (rw == WRITE) {
- if (likely(!bio_empty_barrier(bio)))
+ if (!(bio->bi_rw & REQ_FLUSH))
dm_rh_dec(ms->rh, map_context->ll);
return error;
}
