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[Qemu-devel] [PATCH v2 05/18] qcow2: Fail write_compressed when overwrit
From: |
Kevin Wolf |
Subject: |
[Qemu-devel] [PATCH v2 05/18] qcow2: Fail write_compressed when overwriting data |
Date: |
Mon, 16 Apr 2012 17:02:03 +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 v2 00/18] qcow2: Basic version 3 support, Kevin Wolf, 2012/04/16
- [Qemu-devel] [PATCH v2 01/18] Specification for qcow2 version 3, Kevin Wolf, 2012/04/16
- [Qemu-devel] [PATCH v2 02/18] qcow2: Save disk size in snapshot header, Kevin Wolf, 2012/04/16
- [Qemu-devel] [PATCH v2 04/18] qcow2: Ignore reserved bits in count_contiguous_clusters(), Kevin Wolf, 2012/04/16
- [Qemu-devel] [PATCH v2 03/18] qcow2: Ignore reserved bits in get_cluster_offset, Kevin Wolf, 2012/04/16
- [Qemu-devel] [PATCH v2 05/18] qcow2: Fail write_compressed when overwriting data,
Kevin Wolf <=
- [Qemu-devel] [PATCH v2 07/18] qcow2: Refactor qcow2_free_any_clusters, Kevin Wolf, 2012/04/16
- [Qemu-devel] [PATCH v2 06/18] qcow2: Ignore reserved bits in L1/L2 entries, Kevin Wolf, 2012/04/16
- [Qemu-devel] [PATCH v2 09/18] qcow2: Ignore reserved bits in refcount table entries, Kevin Wolf, 2012/04/16
- [Qemu-devel] [PATCH v2 12/18] qcow2: Support reading zero clusters, Kevin Wolf, 2012/04/16
- [Qemu-devel] [PATCH v2 08/18] qcow2: Simplify count_cow_clusters, Kevin Wolf, 2012/04/16
- [Qemu-devel] [PATCH v2 10/18] qcow2: Ignore reserved bits in check_refcounts, Kevin Wolf, 2012/04/16
- [Qemu-devel] [PATCH v2 13/18] qcow2: Support for feature table header extension, Kevin Wolf, 2012/04/16
- [Qemu-devel] [PATCH v2 14/18] qemu-iotests: add a simple test for write_zeroes, Kevin Wolf, 2012/04/16
- [Qemu-devel] [PATCH v2 15/18] qemu-iotests: Test backing file COW with zero clusters, Kevin Wolf, 2012/04/16
- [Qemu-devel] [PATCH v2 17/18] qemu-iotests: Add -o and make v3 the default for qcow2, Kevin Wolf, 2012/04/16