Sometimes this may safe some space...
https://jira.sw.ru/browse/PSBM-123748
Signed-off-by: Kirill Tkhai <ktk...@virtuozzo.com>
---
drivers/md/dm-ploop-map.c | 24 ++++++++++++++++++++++++
1 file changed, 24 insertions(+)
diff --git a/drivers/md/dm-ploop-map.c b/drivers/md/dm-ploop-map.c
index 4b12b5fc082a..f193b25cbd28 100644
--- a/drivers/md/dm-ploop-map.c
+++ b/drivers/md/dm-ploop-map.c
@@ -397,6 +397,27 @@ static void maybe_unlink_completed_bio(struct ploop
*ploop, struct bio *bio)
queue_work(ploop->wq, &ploop->worker);
}
+static bool bio_endio_if_all_zeros(struct bio *bio)
+{
+ struct bvec_iter bi = {
+ .bi_size = bio->bi_iter.bi_size,
+ };
+ struct bio_vec bv;
+ void *data, *ret;
+
+ for_each_bvec(bv, bio->bi_io_vec, bi, bi) {
+ data = kmap(bv.bv_page);
+ ret = memchr_inv(data + bv.bv_offset, 0, bv.bv_len);
+ kunmap(bv.bv_page);
+ if (ret)
+ return false;
+ }
+
+ bio->bi_status = BLK_STS_OK;
+ bio_endio(bio);
+ return true;
+}
+
static void handle_discard_bio(struct ploop *ploop, struct bio *bio,
unsigned int cluster, unsigned int dst_cluster)
{
@@ -1326,6 +1347,9 @@ static int process_one_deferred_bio(struct ploop *ploop,
struct bio *bio,
goto out;
}
+ if (unlikely(bio_endio_if_all_zeros(bio)))
+ goto out;
+
/* Cluster exists nowhere. Allocate it and setup bio as outrunning */
ret = locate_new_cluster_and_attach_bio(ploop, piwb, cluster,
&dst_cluster, bio);
_______________________________________________
Devel mailing list
Devel@openvz.org
https://lists.openvz.org/mailman/listinfo/devel
