[PATCH 11/11] bcache: Fix flushes in writeback mode
From: Kent Overstreet <hidden>
Date: 2013-09-24 06:19:37
Also in:
lkml
Subsystem:
bcache (block layer cache), the rest · Maintainers:
Coly Li, Kent Overstreet, Linus Torvalds
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 <redacted> Cc: linux-stable <redacted> # >= v3.10 --- drivers/md/bcache/request.c | 15 +++++++++------ 1 file changed, 9 insertions(+), 6 deletions(-)
diff --git a/drivers/md/bcache/request.c b/drivers/md/bcache/request.c
index 786a1a4..71eb233 100644
--- a/drivers/md/bcache/request.c
+++ b/drivers/md/bcache/request.c@@ -997,14 +997,17 @@ static void request_write(struct cached_dev *dc, struct search *s) } 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; }
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1.8.4.rc3