In some cases bi_io_vec ptr is not initiallized, which can happen after bio reset and qcow2 can try to use the ptr before it is reinitiallized with bi_inline_vecs. in that case fallback to use bi_inline_vecs ptr. bi_inline_vecs are used when there are less than 4 io vecs.
Add some warnings to trace the problem further if it happens again. https://virtuozzo.atlassian.net/browse/PSBM-157238 Signed-off-by: Alexander Atanasov <alexander.atana...@virtuozzo.com> --- drivers/md/dm-qcow2-map.c | 13 ++++++++++++- 1 file changed, 12 insertions(+), 1 deletion(-) diff --git a/drivers/md/dm-qcow2-map.c b/drivers/md/dm-qcow2-map.c index 8f871c0522aac..53bed6c0a30ae 100644 --- a/drivers/md/dm-qcow2-map.c +++ b/drivers/md/dm-qcow2-map.c @@ -1245,6 +1245,7 @@ static void __submit_rw_mapped(struct qcow2 *qcow2, struct qio *qio, u32 nr_segs rw = (op_is_write(qio->bi_op) ? WRITE : READ); bvec = __bvec_iter_bvec(qio->bi_io_vec, qio->bi_iter); + WARN_ON_ONCE(!bvec); pos = to_bytes(qio->bi_iter.bi_sector); iov_iter_bvec(&iter, rw, bvec, nr_segs, qio->bi_iter.bi_size); @@ -3509,7 +3510,15 @@ static void prepare_one_embedded_qio(struct qcow2 *qcow2, struct qio *qio, } else { /* Single bio already provides bvec array */ bvec = rq->bio->bi_io_vec; - + WARN_ON_ONCE(!bvec); + if (!bvec) { + bvec = rq->bio->bi_inline_vecs; + if (unlikely(!bvec)) { + printk(KERN_ERR "Expecting inline bvec\n"); + WARN_ON_ONCE(1); + goto err; + } + } qio->bi_iter = rq->bio->bi_iter; } @@ -3706,6 +3715,7 @@ static int prepare_sliced_data_write(struct qcow2 *qcow2, struct qio *qio, } write_qio->bi_io_vec = qvec->bvec; + WARN_ON_ONCE(!write_qio->bi_io_vec); write_qio->bi_iter.bi_idx = 0; write_qio->bi_iter.bi_bvec_done = 0; @@ -4162,6 +4172,7 @@ void qcow2_submit_embedded_qio(struct qcow2_target *tgt, struct qio *qio) qcow2 = qcow2_ref_inc(tgt, &ref_index); if (blk_rq_bytes(rq)) { + WARN_ON_ONCE(rq->bio && !rq->bio->bi_io_vec); queue_list_id = QLIST_EMBEDDED; worker = &qcow2->worker; } else { -- 2.43.0 _______________________________________________ Devel mailing list Devel@openvz.org https://lists.openvz.org/mailman/listinfo/devel
