[Qemu-devel] [RFC V3 05/24] qcow2: Create a way to link to l2 tables in dedup.

["Benoît Canet" <benoit@irqsave.net>]

Signed-off-by: Benoit Canet <benoit@irqsave.net>
---
 block/qcow2-cluster.c |    9 +++++++--
 block/qcow2.c         |    2 ++
 block/qcow2.h         |    2 ++
 3 files changed, 11 insertions(+), 2 deletions(-)

diff --git a/block/qcow2-cluster.c b/block/qcow2-cluster.c
index e179211..9a07191 100644
--- a/block/qcow2-cluster.c
+++ b/block/qcow2-cluster.c
@@ -683,7 +683,8 @@ 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));
      }
 
 
@@ -696,7 +697,7 @@ 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);
         }
@@ -922,6 +923,8 @@ again:
     *m = (QCowL2Meta) {
         .cluster_offset     = cluster_offset,
         .nb_clusters        = 0,
+        .oflag_copied       = true,
+        .overwrite          = false,
     };
     qemu_co_queue_init(&m->dependent_requests);
 
@@ -970,6 +973,8 @@ again:
                 .n_start        = keep_clusters == 0 ? n_start : 0,
                 .nb_clusters    = nb_clusters,
                 .nb_available   = MIN(requested_sectors, avail_sectors),
+                .oflag_copied   = true,
+                .overwrite      = false,
             };
             qemu_co_queue_init(&m->dependent_requests);
             QLIST_INSERT_HEAD(&s->cluster_allocs, m, next_in_flight);
diff --git a/block/qcow2.c b/block/qcow2.c
index c1ff31f..b5276c0 100644
--- a/block/qcow2.c
+++ b/block/qcow2.c
@@ -776,6 +776,8 @@ static coroutine_fn int qcow2_co_writev(BlockDriverState *bs,
     uint8_t *cluster_data = NULL;
     QCowL2Meta l2meta = {
         .nb_clusters = 0,
+        .oflag_copied = true,
+        .overwrite = false,
     };
 
     trace_qcow2_writev_start_req(qemu_coroutine_self(), sector_num,
diff --git a/block/qcow2.h b/block/qcow2.h
index ee9aecc..ccb24ad 100644
--- a/block/qcow2.h
+++ b/block/qcow2.h
@@ -231,6 +231,8 @@ typedef struct QCowL2Meta
     int n_start;
     int nb_available;
     int nb_clusters;
+    bool oflag_copied;
+    bool overwrite;
     CoQueue dependent_requests;
 
     QLIST_ENTRY(QCowL2Meta) next_in_flight;
-- 
1.7.10.4