debian/patches/pve/0045-block-io-accept-NULL-qiov-in-bdrv_pad_request.patch

   1 From 0000000000000000000000000000000000000000 Mon Sep 17 00:00:00 2001
   2 From: Stefan Reiter <s.reiter@proxmox.com>
   3 Date: Tue, 2 Mar 2021 16:11:54 +0100
   4 Subject: [PATCH] block/io: accept NULL qiov in bdrv_pad_request
   5
   6 Some operations, e.g. block-stream, perform reads while discarding the
   7 results (only copy-on-read matters). In this case they will pass NULL as
   8 the target QEMUIOVector, which will however trip bdrv_pad_request, since
   9 it wants to extend its passed vector.
  10
  11 Simply check for NULL and do nothing, there's no reason to pad the
  12 target if it will be discarded anyway.
  13 ---
  14  block/io.c | 4 ++++
  15  1 file changed, 4 insertions(+)
  16
  17 diff --git a/block/io.c b/block/io.c
  18 index ca2dca3007..a9e70a4f91 100644
  19 --- a/block/io.c
  20 +++ b/block/io.c
  21 @@ -1731,6 +1731,10 @@ static int bdrv_pad_request(BlockDriverState *bs,
  22  {
  23      int ret;
  24
  25 +    if (!qiov) {
  26 +        return 0;
  27 +    }
  28 +
  29      bdrv_check_qiov_request(*offset, *bytes, *qiov, *qiov_offset, &error_abort);
  30
  31      if (!bdrv_init_padding(bs, *offset, *bytes, pad)) {