@@ -693,7 +693,8 @@ int qcow2_alloc_cluster_link_l2(BlockDriverState *bs, QCowL2Meta *m)
old_cluster[j++] = l2_table[l2_index + i];
l2_table[l2_index + i] = cpu_to_be64((cluster_offset +
- (i << s->cluster_bits)) | QCOW_OFLAG_COPIED);
+ (i << s->cluster_bits)) |
+ (m->oflag_copied ? QCOW_OFLAG_COPIED : 0));
}
@@ -706,7 +707,7 @@ int qcow2_alloc_cluster_link_l2(BlockDriverState *bs, QCowL2Meta *m)
* If this was a COW, we need to decrease the refcount of the old cluster.
* Also flush bs->file to get the right order for L2 and refcount update.
*/
- if (j != 0) {
+ if (!m->overwrite && j != 0) {
for (i = 0; i < j; i++) {
qcow2_free_any_clusters(bs, be64_to_cpu(old_cluster[i]), 1);
}
@@ -1006,6 +1007,9 @@ again:
.offset = nb_sectors * BDRV_SECTOR_SIZE,
.nb_sectors = avail_sectors - nb_sectors,
},
+
+ .oflag_copied = true,
+ .overwrite = false,
};
qemu_co_queue_init(&(*m)->dependent_requests);
QLIST_INSERT_HEAD(&s->cluster_allocs, *m, next_in_flight);
@@ -63,6 +63,10 @@
#define DEFAULT_CLUSTER_SIZE 65536
#define HASH_LENGTH 32
+/* indicate that the hash structure is empty and miss offset */
+#define QCOW_FLAG_EMPTY (1LL << 62)
+/* indicate that the cluster for this hash has QCOW_OFLAG_COPIED on disk */
+#define QCOW_FLAG_FIRST (1LL << 63)
typedef enum {
QCOW_DEDUP_STOPPED,
@@ -304,6 +308,11 @@ typedef struct QCowL2Meta
*/
CoQueue dependent_requests;
+ /* set to true if QCOW_OFLAG_COPIED must be set in the L2 table entry */
+ bool oflag_copied;
+ /* set to true if we are overwriting an L2 table entry */
+ bool overwrite;
+
/**
* The COW Region between the start of the first allocated cluster and the
* area the guest actually writes to.
Signed-off-by: Benoit Canet <benoit@irqsave.net> --- block/qcow2-cluster.c | 8 ++++++-- block/qcow2.h | 9 +++++++++ 2 files changed, 15 insertions(+), 2 deletions(-)