qcow2: Bring synchronous read/write back to life

[qemu.git] / block / qcow2.c

diff --git a/block/qcow2.c b/block/qcow2.c
index dd32ea2078df050e4f91e4055db1974e7663dbf2..ced257e9f57c2c8a1e8b6715453a2da5fd08fc7a 100644 (file)
--- a/block/qcow2.c
+++ b/block/qcow2.c
@@ -855,6 +855,51 @@ static int qcow_make_empty(BlockDriverState *bs)
     return 0;
 }
 
+static int qcow2_write(BlockDriverState *bs, int64_t sector_num,
+                     const uint8_t *buf, int nb_sectors)
+{
+    BDRVQcowState *s = bs->opaque;
+    int ret, index_in_cluster, n;
+    uint64_t cluster_offset;
+    int n_end;
+    QCowL2Meta l2meta;
+
+    while (nb_sectors > 0) {
+        memset(&l2meta, 0, sizeof(l2meta));
+
+        index_in_cluster = sector_num & (s->cluster_sectors - 1);
+        n_end = index_in_cluster + nb_sectors;
+        if (s->crypt_method &&
+            n_end > QCOW_MAX_CRYPT_CLUSTERS * s->cluster_sectors)
+            n_end = QCOW_MAX_CRYPT_CLUSTERS * s->cluster_sectors;
+        cluster_offset = qcow2_alloc_cluster_offset(bs, sector_num << 9,
+                                              index_in_cluster,
+                                              n_end, &n, &l2meta);
+        if (!cluster_offset)
+            return -1;
+        if (s->crypt_method) {
+            qcow2_encrypt_sectors(s, sector_num, s->cluster_data, buf, n, 1,
+                            &s->aes_encrypt_key);
+            ret = bdrv_pwrite(s->hd, cluster_offset + index_in_cluster * 512,
+                              s->cluster_data, n * 512);
+        } else {
+            ret = bdrv_pwrite(s->hd, cluster_offset + index_in_cluster * 512, buf, n * 512);
+        }
+        if (ret != n * 512 || qcow2_alloc_cluster_link_l2(bs, cluster_offset, &l2meta) < 0) {
+            qcow2_free_any_clusters(bs, cluster_offset, l2meta.nb_clusters);
+            return -1;
+        }
+        nb_sectors -= n;
+        sector_num += n;
+        buf += n * 512;
+        if (l2meta.nb_clusters != 0) {
+            LIST_REMOVE(&l2meta, next_in_flight);
+        }
+    }
+    s->cluster_cache_offset = -1; /* disable compressed cache */
+    return 0;
+}
+
 /* XXX: put compressed sectors first, then all the cluster aligned
    tables to avoid losing bytes in alignment */
 static int qcow_write_compressed(BlockDriverState *bs, int64_t sector_num,
@@ -1037,8 +1082,10 @@ static BlockDriver bdrv_qcow2 = {
     .bdrv_set_key      = qcow_set_key,
     .bdrv_make_empty   = qcow_make_empty,
 
-    .bdrv_aio_readv    = qcow_aio_readv,
-    .bdrv_aio_writev   = qcow_aio_writev,
+    .bdrv_read          = qcow2_read,
+    .bdrv_write         = qcow2_write,
+    .bdrv_aio_readv     = qcow_aio_readv,
+    .bdrv_aio_writev    = qcow_aio_writev,
     .bdrv_write_compressed = qcow_write_compressed,
 
     .bdrv_snapshot_create   = qcow2_snapshot_create,