When a lba either hits the cache or corresponds to an empty entry in the
L2P table, we need to advance the bio according to the position in which
the lba is located. Otherwise, we will copy data in the wrong page, thus
causing data corruption for the application.

In case of a cache hit, we assumed that bio->bi_iter.bi_idx would
contain the correct index, but this is no necessarily true. Instead, use
the local bio advance counter and iterator. This guarantees that lbas
hitting the cache are copied into the right bv_page.

In case of an empty L2P entry, we omitted to advance the bio. In the
cases when the same I/O also contains a cache hit, data corresponding
to this lba will be copied to the wrong bv_page. Fix this by advancing
the bio as we do in the case of a cache hit.

Fixes: a4bd217b4326 lightnvm: physical block device (pblk) target

Signed-off-by: Javier González <redacted>
---
 drivers/lightnvm/pblk-rb.c   |  4 ++--
 drivers/lightnvm/pblk-read.c | 19 ++++++++++++++-----
 drivers/lightnvm/pblk.h      |  2 +-
 3 files changed, 17 insertions(+), 8 deletions(-)

diff --git a/drivers/lightnvm/pblk-rb.c b/drivers/lightnvm/pblk-rb.c
index 5ecc154f6831..2e88c3d6d9a1 100644
--- a/drivers/lightnvm/pblk-rb.c
+++ b/drivers/lightnvm/pblk-rb.c

@@ -657,7 +657,7 @@ unsigned int pblk_rb_read_to_bio(struct pblk_rb *rb, struct nvm_rq *rqd,
  * be directed to disk.
  */
 int pblk_rb_copy_to_bio(struct pblk_rb *rb, struct bio *bio, sector_t lba,
-			struct ppa_addr ppa, int bio_iter)
+			struct ppa_addr ppa, int bio_iter, int advanced_bio)