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authorKevin Wolf <kwolf@redhat.com>2018-06-28 17:05:45 +0200
committerKevin Wolf <kwolf@redhat.com>2018-06-29 14:20:56 +0200
commit8b24cd141549b5b264baeddd4e72902cfb5de23b (patch)
tree2856eb7c876ed7578c0620270344b90b4d0bc6f9
parent93a3642efcadf4ad6045ccea38a05ff5297dfe26 (diff)
qcow2: Free allocated clusters on write error
If we managed to allocate the clusters, but then failed to write the data, there's a good chance that we'll still be able to free the clusters again in order to avoid cluster leaks (the refcounts are cached, so even if we can't write them out right now, we may be able to do so when the VM is resumed after a werror=stop/enospc pause). Signed-off-by: Kevin Wolf <kwolf@redhat.com> Reviewed-by: Max Reitz <mreitz@redhat.com> Reviewed-by: Eric Blake <eblake@redhat.com> Tested-by: Eric Blake <eblake@redhat.com>
-rw-r--r--block/qcow2-cluster.c11
-rw-r--r--block/qcow2.c2
-rw-r--r--block/qcow2.h1
3 files changed, 14 insertions, 0 deletions
diff --git a/block/qcow2-cluster.c b/block/qcow2-cluster.c
index 0d74584c9b..d37fe08b3d 100644
--- a/block/qcow2-cluster.c
+++ b/block/qcow2-cluster.c
@@ -994,6 +994,17 @@ err:
return ret;
}
+/**
+ * Frees the allocated clusters because the request failed and they won't
+ * actually be linked.
+ */
+void qcow2_alloc_cluster_abort(BlockDriverState *bs, QCowL2Meta *m)
+{
+ BDRVQcow2State *s = bs->opaque;
+ qcow2_free_clusters(bs, m->alloc_offset, m->nb_clusters << s->cluster_bits,
+ QCOW2_DISCARD_NEVER);
+}
+
/*
* Returns the number of contiguous clusters that can be used for an allocating
* write, but require COW to be performed (this includes yet unallocated space,
diff --git a/block/qcow2.c b/block/qcow2.c
index 78aeb1f9ea..286640c0e3 100644
--- a/block/qcow2.c
+++ b/block/qcow2.c
@@ -1775,6 +1775,8 @@ static coroutine_fn int qcow2_handle_l2meta(BlockDriverState *bs,
if (ret) {
goto out;
}
+ } else {
+ qcow2_alloc_cluster_abort(bs, l2meta);
}
/* Take the request off the list of running requests */
diff --git a/block/qcow2.h b/block/qcow2.h
index 01b5250415..1c9c0d3631 100644
--- a/block/qcow2.h
+++ b/block/qcow2.h
@@ -614,6 +614,7 @@ uint64_t qcow2_alloc_compressed_cluster_offset(BlockDriverState *bs,
int compressed_size);
int qcow2_alloc_cluster_link_l2(BlockDriverState *bs, QCowL2Meta *m);
+void qcow2_alloc_cluster_abort(BlockDriverState *bs, QCowL2Meta *m);
int qcow2_cluster_discard(BlockDriverState *bs, uint64_t offset,
uint64_t bytes, enum qcow2_discard_type type,
bool full_discard);