bcache: Fix a null ptr deref regression

commit 2fe80d3bbf1c8bd9efc5b8154207c8dd104e7306 upstream.

Commit c0f04d88e46d ("bcache: Fix flushes in writeback mode") was fixing
a reported data corruption bug, but it seems some last minute
refactoring or rebasing introduced a null pointer deref.

Signed-off-by: Kent Overstreet <kmo@daterainc.com>
Reported-by: Gabriel de Perthuis <g2p.code@gmail.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

1 files changed, 1 insertions, 2 deletions

diff --git a/drivers/md/bcache/request.c b/drivers/md/bcache/request.c
index 2fe37fac1ca2..cbcf8b301edc 100644
--- a/drivers/md/bcache/request.c
+++ b/drivers/md/bcache/request.c
@@ -1055,6 +1055,7 @@ static void request_write(struct cached_dev *dc, struct search *s)
         } else {
                 trace_bcache_writeback(s->orig_bio);
                 bch_writeback_add(dc, bio_sectors(bio));
+                s->op.cache_bio = bio;
 
                 if (bio->bi_rw & REQ_FLUSH) {
                         /* Also need to send a flush to the backing device */
@@ -1067,8 +1068,6 @@ static void request_write(struct cached_dev *dc, struct search *s)
                         flush->bi_private = cl;
 
                         closure_bio_submit(flush, cl, s->d);
-                } else {
-                        s->op.cache_bio = bio;
                 }
         }
 out: