[Qemu-devel] [RFC V8 11/24] qcow2: Add qcow2_dedup_store_new_hashes.

[Benoît Canet]

Signed-off-by: Benoit Canet <address@hidden>
---
 block/qcow2-dedup.c |   97 ++++++++++++++++++++++++++++++++++++++++++++++++++-
 block/qcow2.h       |    6 +++-
 2 files changed, 101 insertions(+), 2 deletions(-)

diff --git a/block/qcow2-dedup.c b/block/qcow2-dedup.c
index 0daf77e..ffbf866 100644
--- a/block/qcow2-dedup.c
+++ b/block/qcow2-dedup.c
@@ -251,6 +251,7 @@ static int qcow2_dedup_link_l2(BlockDriverState *bs,
 static int qcow2_clear_l2_copied_flag_if_needed(BlockDriverState *bs,
                                                 QCowHashInfo *hash_info)
 {
+    BDRVQcowState *s = bs->opaque;
     int ret = 0;
     uint64_t first_logical_sect = hash_info->first_logical_sect;
 
@@ -273,7 +274,8 @@ static int 
qcow2_clear_l2_copied_flag_if_needed(BlockDriverState *bs,
     /* remember that we don't need to clear QCOW_OFLAG_COPIED again */
     hash_info->first_logical_sect = first_logical_sect;
 
-    return 0;
+    /* clear the QCOW_OFLAG_COPIED flag from disk */
+    return qcow2_store_insert(bs, &s->key_value_store, hash_info);
 }
 
 /* This function deduplicate a cluster
@@ -534,3 +536,96 @@ exit:
 
     return deduped_clusters_nr * s->cluster_sectors - start_index;
 }
+
+static inline bool is_hash_info_empty(QCowHashInfo *hash_info)
+{
+    return hash_info->physical_sect & QCOW_DEDUP_FLAG_EMPTY;
+}
+
+/* This function store a hash information to disk and RAM
+ *
+ * @hash_info:      the QCowHashInfo to process
+ * @logical_sect:   the logical sector of the cluster seen by the guest
+ * @physical_sect:  the physical sector of the stored cluster
+ * @ret:            0 on success, negative on error
+ */
+static int qcow2_store_hash(BlockDriverState *bs,
+                            QCowHashInfo *hash_info,
+                            uint64_t logical_sect,
+                            uint64_t physical_sect)
+{
+    BDRVQcowState *s = bs->opaque;
+    int ret = 0;
+
+    ret = qcow2_store_get(bs, &s->key_value_store, hash_info);
+
+    /* no hash info found in store or error */
+    if (ret <= 0) {
+        return ret;
+    }
+
+    /* the hash info information are already completed */
+    if (!is_hash_info_empty(hash_info)) {
+        return 0;
+    }
+
+    /* Remember that this QCowHashInfo represents the first occurrence of the
+     * cluster so we will be able to clear QCOW_OFLAG_COPIED from the L2 table
+     * entry when refcount will go > 1.
+     */
+    logical_sect = logical_sect | QCOW_OFLAG_COPIED;
+
+    /* fill the missing fields of the hash info */
+    hash_info->physical_sect = physical_sect;
+    hash_info->first_logical_sect = logical_sect;
+
+    /* write the hash into the key value store */
+    return qcow2_store_insert(bs, &s->key_value_store, hash_info);
+}
+
+/* This function store the hashes of the clusters which are not duplicated
+ *
+ * @ds:            The deduplication state
+ * @count:         the number of dedup hash to process
+ * @logical_sect:  logical offset of the first cluster (in sectors)
+ * @physical_sect: offset of the first cluster (in sectors)
+ * @ret:           0 on succes, errno on error
+ */
+int qcow2_dedup_store_new_hashes(BlockDriverState *bs,
+                                 QCowDedupState *ds,
+                                 int count,
+                                 uint64_t logical_sect,
+                                 uint64_t physical_sect)
+{
+    int ret = 0;
+    int i = 0;
+    BDRVQcowState *s = bs->opaque;
+    QCowHashElement *dedup_hash, *next_dedup_hash;
+
+    /* round values on cluster boundaries for easier cluster deletion */
+    logical_sect = logical_sect & ~(s->cluster_sectors - 1);
+    physical_sect = physical_sect & ~(s->cluster_sectors - 1);
+
+    QTAILQ_FOREACH_SAFE(dedup_hash, &ds->undedupables, next, next_dedup_hash) {
+
+        ret = qcow2_store_hash(bs,
+                               &dedup_hash->hash_info,
+                               logical_sect + i * s->cluster_sectors,
+                               physical_sect + i * s->cluster_sectors);
+
+        QTAILQ_REMOVE(&ds->undedupables, dedup_hash, next);
+        g_free(dedup_hash);
+
+        if (ret < 0) {
+            break;
+        }
+
+        i++;
+
+        if (i == count) {
+            break;
+        }
+    }
+
+    return ret;
+}
diff --git a/block/qcow2.h b/block/qcow2.h
index 3346842..ff26e81 100644
--- a/block/qcow2.h
+++ b/block/qcow2.h
@@ -742,6 +742,10 @@ int qcow2_dedup(BlockDriverState *bs,
                 uint64_t sector_num,
                 uint8_t *data,
                 int data_nr);
-
+int qcow2_dedup_store_new_hashes(BlockDriverState *bs,
+                                 QCowDedupState *ds,
+                                 int count,
+                                 uint64_t logical_sect,
+                                 uint64_t physical_sect);
 
 #endif
-- 
1.7.10.4