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authorKevin Wolf <kwolf@redhat.com>2013-03-26 17:50:08 +0100
committerStefan Hajnoczi <stefanha@redhat.com>2013-03-28 11:52:43 +0100
commite62daaf67958e8274547ddac87cb0a177a869216 (patch)
tree47879b5f95f91215bcbd6b34573c0ef24a7c25c6 /block/qcow2-cluster.c
parentc53ede9f6d8f0de7939eea676c1398c4073ff35e (diff)
qcow2: handle_copied(): Implement non-zero host_offset
Look only for clusters that start at a given physical offset. Signed-off-by: Kevin Wolf <kwolf@redhat.com> Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
Diffstat (limited to 'block/qcow2-cluster.c')
-rw-r--r--block/qcow2-cluster.c28
1 files changed, 20 insertions, 8 deletions
diff --git a/block/qcow2-cluster.c b/block/qcow2-cluster.c
index 5e5465dcac..239a997027 100644
--- a/block/qcow2-cluster.c
+++ b/block/qcow2-cluster.c
@@ -830,8 +830,6 @@ static int handle_dependencies(BlockDriverState *bs, uint64_t guest_offset,
* the length of the area that can be written to.
*
* -errno: in error cases
- *
- * TODO Make non-zero host_offset behave like describe above
*/
static int handle_copied(BlockDriverState *bs, uint64_t guest_offset,
uint64_t *host_offset, uint64_t *bytes, QCowL2Meta **m)
@@ -846,7 +844,6 @@ static int handle_copied(BlockDriverState *bs, uint64_t guest_offset,
trace_qcow2_handle_copied(qemu_coroutine_self(), guest_offset, *host_offset,
*bytes);
- assert(*host_offset == 0);
/*
* Calculate the number of clusters to look for. We stop at L2 table
@@ -870,6 +867,16 @@ static int handle_copied(BlockDriverState *bs, uint64_t guest_offset,
if (qcow2_get_cluster_type(cluster_offset) == QCOW2_CLUSTER_NORMAL
&& (cluster_offset & QCOW_OFLAG_COPIED))
{
+ /* If a specific host_offset is required, check it */
+ bool offset_matches =
+ (cluster_offset & L2E_OFFSET_MASK) == *host_offset;
+
+ if (*host_offset != 0 && !offset_matches) {
+ *bytes = 0;
+ ret = 0;
+ goto out;
+ }
+
/* We keep all QCOW_OFLAG_COPIED clusters */
keep_clusters =
count_contiguous_clusters(nb_clusters, s->cluster_size,
@@ -883,19 +890,22 @@ static int handle_copied(BlockDriverState *bs, uint64_t guest_offset,
ret = 1;
} else {
- cluster_offset = 0;
ret = 0;
}
- cluster_offset &= L2E_OFFSET_MASK;
- *host_offset = cluster_offset;
-
/* Cleanup */
+out:
pret = qcow2_cache_put(bs, s->l2_table_cache, (void**) &l2_table);
if (pret < 0) {
return pret;
}
+ /* Only return a host offset if we actually made progress. Otherwise we
+ * would make requirements for handle_alloc() that it can't fulfill */
+ if (ret) {
+ *host_offset = cluster_offset & L2E_OFFSET_MASK;
+ }
+
return ret;
}
@@ -1165,7 +1175,6 @@ again:
/*
* 2. Count contiguous COPIED clusters.
- * TODO: Consider cluster_offset if set in step 1c.
*/
uint64_t tmp_bytes = cur_bytes;
ret = handle_copied(bs, offset, &cluster_offset, &tmp_bytes, m);
@@ -1179,6 +1188,9 @@ again:
if (!*host_offset) {
*host_offset = cluster_offset;
}
+ } else if (cur_bytes == 0) {
+ keep_clusters = 0;
+ goto done;
} else {
keep_clusters = 0;
}