qcow2: Employ metadata overlap checks

The pre-write overlap check function is now called before most of the
qcow2 writes (aborting it on collision or other error).

Signed-off-by: Max Reitz <mreitz@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>

1 files changed, 21 insertions, 0 deletions

diff --git a/block/qcow2-cluster.c b/block/qcow2-cluster.c
index cca76d4fcd..7c248aaede 100644
--- a/block/qcow2-cluster.c
+++ b/block/qcow2-cluster.c
@@ -80,6 +80,14 @@ int qcow2_grow_l1_table(BlockDriverState *bs, uint64_t min_size,
         goto fail;
     }
 
+    /* the L1 position has not yet been updated, so these clusters must
+     * indeed be completely free */
+    ret = qcow2_pre_write_overlap_check(bs, QCOW2_OL_DEFAULT,
+                                        new_l1_table_offset, new_l1_size2);
+    if (ret < 0) {
+        goto fail;
+    }
+
     BLKDBG_EVENT(bs->file, BLKDBG_L1_GROW_WRITE_TABLE);
     for(i = 0; i < s->l1_size; i++)
         new_l1_table[i] = cpu_to_be64(new_l1_table[i]);
@@ -149,6 +157,13 @@ static int write_l1_entry(BlockDriverState *bs, int l1_index)
         buf[i] = cpu_to_be64(s->l1_table[l1_start_index + i]);
     }
 
+    ret = qcow2_pre_write_overlap_check(bs,
+            QCOW2_OL_DEFAULT & ~QCOW2_OL_ACTIVE_L1,
+            s->l1_table_offset + 8 * l1_start_index, sizeof(buf));
+    if (ret < 0) {
+        return ret;
+    }
+
     BLKDBG_EVENT(bs->file, BLKDBG_L1_UPDATE);
     ret = bdrv_pwrite_sync(bs->file, s->l1_table_offset + 8 * l1_start_index,
         buf, sizeof(buf));
@@ -368,6 +383,12 @@ static int coroutine_fn copy_sectors(BlockDriverState *bs,
                         &s->aes_encrypt_key);
     }
 
+    ret = qcow2_pre_write_overlap_check(bs, QCOW2_OL_DEFAULT,
+            cluster_offset + n_start * BDRV_SECTOR_SIZE, n * BDRV_SECTOR_SIZE);
+    if (ret < 0) {
+        goto out;
+    }
+
     BLKDBG_EVENT(bs->file, BLKDBG_COW_WRITE);
     ret = bdrv_co_writev(bs->file, (cluster_offset >> 9) + n_start, n, &qiov);
     if (ret < 0) {