diff --git a/block/io.c b/block/io.c
index f191a3fa1e..237d7f40f5 100644
--- a/block/io.c
+++ b/block/io.c
@@ -1872,7 +1872,7 @@ bdrv_co_write_req_finish(BdrvChild *child, int64_t offset, uint64_t bytes,
  */
 static int coroutine_fn bdrv_aligned_pwritev(BdrvChild *child,
     BdrvTrackedRequest *req, int64_t offset, unsigned int bytes,
-    int64_t align, QEMUIOVector *qiov, int flags)
+    int64_t align, QEMUIOVector *qiov, size_t qiov_offset, int flags)
 {
     BlockDriverState *bs = child->bs;
     BlockDriver *drv = bs->drv;
@@ -1892,7 +1892,7 @@ static int coroutine_fn bdrv_aligned_pwritev(BdrvChild *child,
     assert(is_power_of_2(align));
     assert((offset & (align - 1)) == 0);
     assert((bytes & (align - 1)) == 0);
-    assert(!qiov || bytes == qiov->size);
+    assert(!qiov || qiov_offset + bytes <= qiov->size);
     max_transfer = QEMU_ALIGN_DOWN(MIN_NON_ZERO(bs->bl.max_transfer, INT_MAX),
                                    align);
 
@@ -1900,7 +1900,7 @@ static int coroutine_fn bdrv_aligned_pwritev(BdrvChild *child,
 
     if (!ret && bs->detect_zeroes != BLOCKDEV_DETECT_ZEROES_OPTIONS_OFF &&
         !(flags & BDRV_REQ_ZERO_WRITE) && drv->bdrv_co_pwrite_zeroes &&
-        qemu_iovec_is_zero(qiov, 0, qiov->size)) {
+        qemu_iovec_is_zero(qiov, qiov_offset, bytes)) {
         flags |= BDRV_REQ_ZERO_WRITE;
         if (bs->detect_zeroes == BLOCKDEV_DETECT_ZEROES_OPTIONS_UNMAP) {
             flags |= BDRV_REQ_MAY_UNMAP;
@@ -1913,15 +1913,15 @@ static int coroutine_fn bdrv_aligned_pwritev(BdrvChild *child,
         bdrv_debug_event(bs, BLKDBG_PWRITEV_ZERO);
         ret = bdrv_co_do_pwrite_zeroes(bs, offset, bytes, flags);
     } else if (flags & BDRV_REQ_WRITE_COMPRESSED) {
-        ret = bdrv_driver_pwritev_compressed(bs, offset, bytes, qiov, 0);
+        ret = bdrv_driver_pwritev_compressed(bs, offset, bytes,
+                                             qiov, qiov_offset);
     } else if (bytes <= max_transfer) {
         bdrv_debug_event(bs, BLKDBG_PWRITEV);
-        ret = bdrv_driver_pwritev(bs, offset, bytes, qiov, 0, flags);
+        ret = bdrv_driver_pwritev(bs, offset, bytes, qiov, qiov_offset, flags);
     } else {
         bdrv_debug_event(bs, BLKDBG_PWRITEV);
         while (bytes_remaining) {
             int num = MIN(bytes_remaining, max_transfer);
-            QEMUIOVector local_qiov;
             int local_flags = flags;
 
             assert(num);
@@ -1931,12 +1931,10 @@ static int coroutine_fn bdrv_aligned_pwritev(BdrvChild *child,
                  * need to flush on the last iteration */
                 local_flags &= ~BDRV_REQ_FUA;
             }
-            qemu_iovec_init(&local_qiov, qiov->niov);
-            qemu_iovec_concat(&local_qiov, qiov, bytes - bytes_remaining, num);
 
             ret = bdrv_driver_pwritev(bs, offset + bytes - bytes_remaining,
-                                      num, &local_qiov, 0, local_flags);
-            qemu_iovec_destroy(&local_qiov);
+                                      num, qiov, bytes - bytes_remaining,
+                                      local_flags);
             if (ret < 0) {
                 break;
             }
@@ -1979,7 +1977,7 @@ static int coroutine_fn bdrv_co_do_zero_pwritev(BdrvChild *child,
 
             qemu_iovec_init_buf(&local_qiov, pad.buf, write_bytes);
             ret = bdrv_aligned_pwritev(child, req, aligned_offset, write_bytes,
-                                       align, &local_qiov,
+                                       align, &local_qiov, 0,
                                        flags & ~BDRV_REQ_ZERO_WRITE);
             if (ret < 0 || pad.merge_reads) {
                 /* Error or all work is done */
@@ -1995,7 +1993,7 @@ static int coroutine_fn bdrv_co_do_zero_pwritev(BdrvChild *child,
         /* Write the aligned part in the middle. */
         uint64_t aligned_bytes = bytes & ~(align - 1);
         ret = bdrv_aligned_pwritev(child, req, offset, aligned_bytes, align,
-                                   NULL, flags);
+                                   NULL, 0, flags);
         if (ret < 0) {
             goto out;
         }
@@ -2009,7 +2007,8 @@ static int coroutine_fn bdrv_co_do_zero_pwritev(BdrvChild *child,
 
         qemu_iovec_init_buf(&local_qiov, pad.tail_buf, align);
         ret = bdrv_aligned_pwritev(child, req, offset, align, align,
-                                   &local_qiov, flags & ~BDRV_REQ_ZERO_WRITE);
+                                   &local_qiov, 0,
+                                   flags & ~BDRV_REQ_ZERO_WRITE);
     }
 
 out:
@@ -2062,7 +2061,7 @@ int coroutine_fn bdrv_co_pwritev(BdrvChild *child,
     }
 
     ret = bdrv_aligned_pwritev(child, &req, offset, bytes, align,
-                               qiov, flags);
+                               qiov, 0, flags);
 
     bdrv_padding_destroy(&pad);