bcache: Fix merge_bvec_fn usage for when it modifies the bvm
Stacked md devices reuse the bvm for the subordinate device, causing
problems...
Reported-by: Michael Balser <michael.balser@profitbricks.com>
Signed-off-by: Kent Overstreet <koverstreet@google.com>
diff --git a/drivers/md/bcache/io.c b/drivers/md/bcache/io.c
index 5304eaa..48efd4d 100644
--- a/drivers/md/bcache/io.c
+++ b/drivers/md/bcache/io.c
@@ -163,13 +163,6 @@
struct bio_vec *bv, *end = bio_iovec(bio) +
min_t(int, bio_segments(bio), max_segments);
- struct bvec_merge_data bvm = {
- .bi_bdev = bio->bi_bdev,
- .bi_sector = bio->bi_sector,
- .bi_size = 0,
- .bi_rw = bio->bi_rw,
- };
-
if (bio->bi_rw & REQ_DISCARD)
return min(ret, q->limits.max_discard_sectors);
@@ -178,12 +171,18 @@
ret = 0;
for (bv = bio_iovec(bio); bv < end; bv++) {
+ struct bvec_merge_data bvm = {
+ .bi_bdev = bio->bi_bdev,
+ .bi_sector = bio->bi_sector,
+ .bi_size = ret << 9,
+ .bi_rw = bio->bi_rw,
+ };
+
if (q->merge_bvec_fn &&
q->merge_bvec_fn(q, &bvm, bv) < (int) bv->bv_len)
break;
- ret += bv->bv_len >> 9;
- bvm.bi_size += bv->bv_len;
+ ret += bv->bv_len >> 9;
}
}