Before a freed cluster can be reused, pending discards for this cluster
must be processed.
The original assumption was that this was not a problem because discards
are only cached during discard/write zeroes operations, which are
synchronous so that no concurrent write requests can cause cluster
allocations.
However, the discard/write zeroes operation itself can allocate a new L2
table (and it has to in order to put zero flags there), so make sure we
can cope with the situation.
This fixes https://bugs.launchpad.net/bugs/
1349972.
Cc: qemu-stable@nongnu.org
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Reviewed-by: Max Reitz <mreitz@redhat.com>
uint64_t i, nb_clusters, refcount;
int ret;
+ /* We can't allocate clusters if they may still be queued for discard. */
+ if (s->cache_discards) {
+ qcow2_process_discards(bs, 0);
+ }
+
nb_clusters = size_to_clusters(s, size);
retry:
for(i = 0; i < nb_clusters; i++) {