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>
This commit is contained in:
Kent Overstreet 2013-04-22 14:44:24 -07:00
parent 1545f13730
commit a09ded8edf

View File

@ -163,13 +163,6 @@ static unsigned bch_bio_max_sectors(struct bio *bio)
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 @@ static unsigned bch_bio_max_sectors(struct bio *bio)
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;
}
}