aboutsummaryrefslogtreecommitdiff
path: root/block/qcow2-refcount.c
diff options
context:
space:
mode:
authorKevin Wolf <kwolf@redhat.com>2015-05-06 13:21:51 +0200
committerKevin Wolf <kwolf@redhat.com>2015-05-22 17:08:00 +0200
commitecbda7a22576591a84f44de1be0150faf6001f1c (patch)
treed01afef7f41119ede1366f027b0023c9a709d240 /block/qcow2-refcount.c
parent8b6db32a4ec47d1171ccfa21d557096b99f4eef0 (diff)
qcow2: Flush pending discards before allocating cluster
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>
Diffstat (limited to 'block/qcow2-refcount.c')
-rw-r--r--block/qcow2-refcount.c5
1 files changed, 5 insertions, 0 deletions
diff --git a/block/qcow2-refcount.c b/block/qcow2-refcount.c
index f47260b808..83467c31c3 100644
--- a/block/qcow2-refcount.c
+++ b/block/qcow2-refcount.c
@@ -833,6 +833,11 @@ static int64_t alloc_clusters_noref(BlockDriverState *bs, uint64_t size)
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++) {