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[Qemu-devel] [PATCH 05/19] qcow2: Fail write_compressed when overwriting
From: |
Kevin Wolf |
Subject: |
[Qemu-devel] [PATCH 05/19] qcow2: Fail write_compressed when overwriting data |
Date: |
Thu, 12 Apr 2012 17:01:06 +0200 |
qcow2_alloc_compressed_cluster_offset() already fails if the copied flag
is set, because qcow2_write_compressed() doesn't perform COW as it would
have to do to allow this.
However, what we really want to check here is whether the cluster is
allocated or not. With internal snapshots the copied flag may not be set
on allocated clusters. Check the cluster offset instead.
Signed-off-by: Kevin Wolf <address@hidden>
---
block/qcow2-cluster.c | 7 +++----
1 files changed, 3 insertions(+), 4 deletions(-)
diff --git a/block/qcow2-cluster.c b/block/qcow2-cluster.c
index 9547fa9..b26028c 100644
--- a/block/qcow2-cluster.c
+++ b/block/qcow2-cluster.c
@@ -571,15 +571,14 @@ uint64_t
qcow2_alloc_compressed_cluster_offset(BlockDriverState *bs,
return 0;
}
+ /* Compression can't overwrite anything. Fail if the cluster was already
+ * allocated. */
cluster_offset = be64_to_cpu(l2_table[l2_index]);
- if (cluster_offset & QCOW_OFLAG_COPIED) {
+ if (cluster_offset & L2E_OFFSET_MASK) {
qcow2_cache_put(bs, s->l2_table_cache, (void**) &l2_table);
return 0;
}
- if (cluster_offset)
- qcow2_free_any_clusters(bs, cluster_offset, 1);
-
cluster_offset = qcow2_alloc_bytes(bs, compressed_size);
if (cluster_offset < 0) {
qcow2_cache_put(bs, s->l2_table_cache, (void**) &l2_table);
--
1.7.6.5
- [Qemu-devel] [PATCH 00/19] qcow2: Add basic version 3 support, Kevin Wolf, 2012/04/12
- [Qemu-devel] [PATCH 05/19] qcow2: Fail write_compressed when overwriting data,
Kevin Wolf <=
- [Qemu-devel] [PATCH 04/19] qcow2: Ignore reserved bits in count_contiguous_clusters(), Kevin Wolf, 2012/04/12
- [Qemu-devel] [PATCH 03/19] qcow2: Ignore reserved bits in get_cluster_offset, Kevin Wolf, 2012/04/12
- [Qemu-devel] [PATCH 02/19] qcow2: Save disk size in snapshot header, Kevin Wolf, 2012/04/12
- [Qemu-devel] [PATCH 09/19] qcow2: Ignore reserved bits in refcount table entries, Kevin Wolf, 2012/04/12
- [Qemu-devel] [PATCH 07/19] qcow2: Refactor qcow2_free_any_clusters, Kevin Wolf, 2012/04/12
- [Qemu-devel] [PATCH 10/19] qcow2: Ignore reserved bits in check_refcounts, Kevin Wolf, 2012/04/12
- [Qemu-devel] [PATCH 18/19] [RFC] Possible qcow2 specification extensions, Kevin Wolf, 2012/04/12
- [Qemu-devel] [PATCH 06/19] qcow2: Ignore reserved bits in L1/L2 entries, Kevin Wolf, 2012/04/12