[Qemu-devel] [RFC PATCH 2/3] block/qcow2: refactor qcow2_co_preadv to use buffer-based io

[Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>]

Use buffer based io in encrypted case.

Signed-off-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
---
 block/qcow2.c | 28 ++++++++++++++++------------
 1 file changed, 16 insertions(+), 12 deletions(-)

diff --git a/block/qcow2.c b/block/qcow2.c
index de524d870b..5b4e5e7537 100644
--- a/block/qcow2.c
+++ b/block/qcow2.c
@@ -2047,19 +2047,15 @@ static coroutine_fn int qcow2_co_preadv(BlockDriverState *bs, uint64_t offset,
                 }
 
                 assert(cur_bytes <= QCOW_MAX_CRYPT_CLUSTERS * s->cluster_size);
-                qemu_iovec_reset(&hd_qiov);
-                qemu_iovec_add(&hd_qiov, cluster_data, cur_bytes);
-            }
 
-            BLKDBG_EVENT(bs->file, BLKDBG_READ_AIO);
-            ret = bdrv_co_preadv(s->data_file,
-                                 cluster_offset + offset_in_cluster,
-                                 cur_bytes, &hd_qiov, 0);
-            if (ret < 0) {
-                goto fail;
-            }
-            if (bs->encrypted) {
-                assert(s->crypto);
+                BLKDBG_EVENT(bs->file, BLKDBG_READ_AIO);
+                ret = bdrv_co_pread(s->data_file,
+                                    cluster_offset + offset_in_cluster,
+                                    cur_bytes, cluster_data, 0);
+                if (ret < 0) {
+                    goto fail;
+                }
+
                 assert((offset & (BDRV_SECTOR_SIZE - 1)) == 0);
                 assert((cur_bytes & (BDRV_SECTOR_SIZE - 1)) == 0);
                 if (qcow2_co_decrypt(bs, cluster_offset, offset,
@@ -2068,6 +2064,14 @@ static coroutine_fn int qcow2_co_preadv(BlockDriverState *bs, uint64_t offset,
                     goto fail;
                 }
                 qemu_iovec_from_buf(qiov, bytes_done, cluster_data, cur_bytes);
+            } else {
+                BLKDBG_EVENT(bs->file, BLKDBG_READ_AIO);
+                ret = bdrv_co_preadv(s->data_file,
+                                     cluster_offset + offset_in_cluster,
+                                     cur_bytes, &hd_qiov, 0);
+                if (ret < 0) {
+                    goto fail;
+                }
             }
             break;
 
-- 
2.18.0