From d87f4c14f27dc82d215108d8392a7d26687148a1 Mon Sep 17 00:00:00 2001 From: Tejun Heo Date: Fri, 3 Sep 2010 11:56:19 +0200 Subject: 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 Cc: dm-devel@redhat.com Cc: Christoph Hellwig Signed-off-by: Jens Axboe --- drivers/md/dm-io.c | 20 ++++---------------- 1 file changed, 4 insertions(+), 16 deletions(-) (limited to 'drivers/md/dm-io.c') diff --git a/drivers/md/dm-io.c b/drivers/md/dm-io.c index 0590c75..136d4f7 100644 --- a/drivers/md/dm-io.c +++ b/drivers/md/dm-io.c @@ -31,7 +31,6 @@ struct dm_io_client { */ struct io { unsigned long error_bits; - unsigned long eopnotsupp_bits; atomic_t count; struct task_struct *sleeper; struct dm_io_client *client; @@ -130,11 +129,8 @@ static void retrieve_io_and_region_from_bio(struct bio *bio, struct io **io, *---------------------------------------------------------------*/ static void dec_count(struct io *io, unsigned int region, int error) { - if (error) { + if (error) set_bit(region, &io->error_bits); - if (error == -EOPNOTSUPP) - set_bit(region, &io->eopnotsupp_bits); - } if (atomic_dec_and_test(&io->count)) { if (io->sleeper) @@ -310,8 +306,8 @@ static void do_region(int rw, unsigned region, struct dm_io_region *where, sector_t remaining = where->count; /* - * where->count may be zero if rw holds a write barrier and we - * need to send a zero-sized barrier. + * where->count may be zero if rw holds a flush and we need to + * send a zero-sized flush. */ do { /* @@ -364,7 +360,7 @@ static void dispatch_io(int rw, unsigned int num_regions, */ for (i = 0; i < num_regions; i++) { *dp = old_pages; - if (where[i].count || (rw & REQ_HARDBARRIER)) + if (where[i].count || (rw & REQ_FLUSH)) do_region(rw, i, where + i, dp, io); } @@ -393,9 +389,7 @@ static int sync_io(struct dm_io_client *client, unsigned int num_regions, return -EIO; } -retry: io->error_bits = 0; - io->eopnotsupp_bits = 0; atomic_set(&io->count, 1); /* see dispatch_io() */ io->sleeper = current; io->client = client; @@ -412,11 +406,6 @@ retry: } set_current_state(TASK_RUNNING); - if (io->eopnotsupp_bits && (rw & REQ_HARDBARRIER)) { - rw &= ~REQ_HARDBARRIER; - goto retry; - } - if (error_bits) *error_bits = io->error_bits; @@ -437,7 +426,6 @@ static int async_io(struct dm_io_client *client, unsigned int num_regions, io = mempool_alloc(client->pool, GFP_NOIO); io->error_bits = 0; - io->eopnotsupp_bits = 0; atomic_set(&io->count, 1); /* see dispatch_io() */ io->sleeper = NULL; io->client = client; -- cgit v1.1