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| author | Max Reitz <mreitz@redhat.com> | 2017-05-04 01:11:18 +0200 |
|---|---|---|
| committer | Kevin Wolf <kwolf@redhat.com> | 2017-05-11 12:08:24 +0200 |
| commit | 564a6b693828ac38f3f562eed9e8b1dc62f45253 (patch) | |
| tree | 466aa3bfb92a455ccb0648dea25659b3563e22df /block/qcow2.h | |
| parent | 92413c16be8eee53a3b60739f2a28a1463651f47 (diff) | |
| download | qemu-564a6b693828ac38f3f562eed9e8b1dc62f45253.tar.gz | |
qcow2: Reuse preallocated zero clusters
Instead of just freeing preallocated zero clusters and completely
allocating them from scratch, reuse them.
We cannot do this in handle_copied(), however, since this is a COW
operation. Therefore, we have to add the new logic to handle_alloc() and
simply return the existing offset if it exists. The only catch is that
we have to convince qcow2_alloc_cluster_link_l2() not to free the old
clusters (because we have reused them).
Reported-by: Eric Blake <eblake@redhat.com>
Signed-off-by: Max Reitz <mreitz@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Diffstat (limited to 'block/qcow2.h')
| -rw-r--r-- | block/qcow2.h | 3 |
1 files changed, 3 insertions, 0 deletions
diff --git a/block/qcow2.h b/block/qcow2.h index f8aeb08794..8731f24b82 100644 --- a/block/qcow2.h +++ b/block/qcow2.h @@ -322,6 +322,9 @@ typedef struct QCowL2Meta /** Number of newly allocated clusters */ int nb_clusters; + /** Do not free the old clusters */ + bool keep_old_clusters; + /** * Requests that overlap with this allocation and wait to be restarted * when the allocating request has completed. |