From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Kent Overstreet , Linus Torvalds Subject: [ 11/57] bcache: Fix flushes in writeback mode Date: Wed, 2 Oct 2013 21:08:37 -0700 Message-Id: <20131003040637.379052155@linuxfoundation.org> In-Reply-To: <20131003040636.600441214@linuxfoundation.org> References: <20131003040636.600441214@linuxfoundation.org> Sender: linux-kernel-owner@vger.kernel.org List-ID: 3.11-stable review patch. If anyone has any objections, please let me know. ------------------ From: Kent Overstreet commit c0f04d88e46d14de51f4baebb6efafb7d59e9f96 upstream. In writeback mode, when we get a cache flush we need to make sure we issue a flush to the backing device. The code for sending down an extra flush was wrong - by cloning the bio we were probably getting flags that didn't make sense for a bare flush, and also the old code was firing for FUA bios, for which we don't need to send a flush to the backing device. This was causing data corruption somehow - the mechanism was never determined, but this patch fixes it for the users that were seeing it. Signed-off-by: Kent Overstreet Signed-off-by: Linus Torvalds Signed-off-by: Greg Kroah-Hartman --- drivers/md/bcache/request.c | 15 +++++++++------ 1 file changed, 9 insertions(+), 6 deletions(-) --- a/drivers/md/bcache/request.c +++ b/drivers/md/bcache/request.c @@ -997,14 +997,17 @@ static void request_write(struct cached_ } else { bch_writeback_add(dc); - if (s->op.flush_journal) { + if (bio->bi_rw & REQ_FLUSH) { /* Also need to send a flush to the backing device */ - s->op.cache_bio = bio_clone_bioset(bio, GFP_NOIO, - dc->disk.bio_split); + struct bio *flush = bio_alloc_bioset(0, GFP_NOIO, + dc->disk.bio_split); - bio->bi_size = 0; - bio->bi_vcnt = 0; - closure_bio_submit(bio, cl, s->d); + flush->bi_rw = WRITE_FLUSH; + flush->bi_bdev = bio->bi_bdev; + flush->bi_end_io = request_endio; + flush->bi_private = cl; + + closure_bio_submit(flush, cl, s->d); } else { s->op.cache_bio = bio; }