Unaligned request could occupy only one cluster. This is true since the
previous commit. Simplify the code taking this considiration into
account.
There are no other changes so far.
Signed-off-by: Denis V. Lunev <d...@openvz.org>
CC: Kevin Wolf <kw...@redhat.com>
---
block/qcow2.c | 23 +++++------------------
1 file changed, 5 insertions(+), 18 deletions(-)
diff --git a/block/qcow2.c b/block/qcow2.c
index 62febfc..9a54bbd 100644
--- a/block/qcow2.c
+++ b/block/qcow2.c
@@ -2436,33 +2436,20 @@ static coroutine_fn int
qcow2_co_write_zeroes(BlockDriverState *bs,
int tail = (sector_num + nb_sectors) % s->cluster_sectors;
if (head != 0 || tail != 0) {
- int64_t cl_end = -1;
+ int64_t cl_start = sector_num - head;
- sector_num -= head;
- nb_sectors += head;
+ assert(cl_start + s->cluster_sectors >= sector_num + nb_sectors);
- if (tail != 0) {
- nb_sectors += s->cluster_sectors - tail;
- }
+ sector_num = cl_start;
+ nb_sectors = s->cluster_sectors;
if (!is_zero_cluster(bs, sector_num)) {
return -ENOTSUP;
}
- if (nb_sectors > s->cluster_sectors) {
- /* Technically the request can cover 2 clusters, f.e. 4k write
- at s->cluster_sectors - 2k offset. One of these cluster can
- be zeroed, one unallocated */
- cl_end = sector_num + nb_sectors - s->cluster_sectors;
- if (!is_zero_cluster(bs, cl_end)) {
- return -ENOTSUP;
- }
- }
-
qemu_co_mutex_lock(&s->lock);
/* We can have new write after previous check */
- if (!is_zero_cluster_top_locked(bs, sector_num) ||
- (cl_end > 0 && !is_zero_cluster_top_locked(bs, cl_end))) {
+ if (!is_zero_cluster_top_locked(bs, sector_num)) {
qemu_co_mutex_unlock(&s->lock);
return -ENOTSUP;
}
--
2.5.0
