diff options
| author | Kevin Wolf <kwolf@redhat.com> | 2012-04-20 15:50:39 +0200 |
|---|---|---|
| committer | Kevin Wolf <kwolf@redhat.com> | 2012-04-20 15:56:19 +0200 |
| commit | f24423bd902bce29bc546cf8d030bfa369726ab1 (patch) | |
| tree | 9851f46dc38df995818691a47577de4f85237d1b /block | |
| parent | 29926112a2fd619abedd8e21002f5d50c476b402 (diff) | |
| download | qemu-f24423bd902bce29bc546cf8d030bfa369726ab1.zip | |
qcow2: Fix refcount block allocation during qcow2_alloc_cluster_at()
Refcount block allocation and refcount table growth rely on
s->free_cluster_index pointing to somewhere after the current
allocation. Change qcow2_alloc_cluster_at() to fulfill this
assumption.
Without this change it could happen that a newly allocated refcount
block and the allocated data block point to the same area in the image
file, causing data corruption in the long run.
This fixes a bug that became first visible after commit 250196f1.
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Diffstat (limited to 'block')
| -rw-r--r-- | block/qcow2-refcount.c | 6 |
1 files changed, 6 insertions, 0 deletions
diff --git a/block/qcow2-refcount.c b/block/qcow2-refcount.c index 565bd54902..6c383373de 100644 --- a/block/qcow2-refcount.c +++ b/block/qcow2-refcount.c @@ -587,6 +587,7 @@ int qcow2_alloc_clusters_at(BlockDriverState *bs, uint64_t offset, { BDRVQcowState *s = bs->opaque; uint64_t cluster_index; + uint64_t old_free_cluster_index; int i, refcount, ret; /* Check how many clusters there are free */ @@ -602,11 +603,16 @@ int qcow2_alloc_clusters_at(BlockDriverState *bs, uint64_t offset, } /* And then allocate them */ + old_free_cluster_index = s->free_cluster_index; + s->free_cluster_index = cluster_index + i; + ret = update_refcount(bs, offset, i << s->cluster_bits, 1); if (ret < 0) { return ret; } + s->free_cluster_index = old_free_cluster_index; + return i; } |