| From | Greg Kroah-Hartman <> | Subject | [ 11/52] bcache: Fix flushes in writeback mode | Date | Wed, 2 Oct 2013 21:05:29 -0700 |
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3.10-stable review patch. If anyone has any objections, please let me know.
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From: Kent Overstreet <kmo@daterainc.com>
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 <kmo@daterainc.com> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
--- 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 @@ -1056,14 +1056,17 @@ static void request_write(struct cached_ trace_bcache_writeback(s->orig_bio); bch_writeback_add(dc, bio_sectors(bio)); - 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; }
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