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 Signed-off-by: Thomas Lamprecht <t.lamprecht@proxmox.com>
  15 ---
  16  block/io.c | 4 ++++
  17  1 file changed, 4 insertions(+)
  18
  19 diff --git a/block/io.c b/block/io.c
  20 index f38e7f81d8..28c3a712b6 100644
  21 --- a/block/io.c
  22 +++ b/block/io.c
  23 @@ -1764,6 +1764,10 @@ static int bdrv_pad_request(BlockDriverState *bs,
  24  {
  25      int ret;
  26
  27 +    if (!qiov) {
  28 +        return 0;
  29 +    }
  30 +
  31      bdrv_check_qiov_request(*offset, *bytes, *qiov, *qiov_offset, &error_abort);
  32
  33      if (!bdrv_init_padding(bs, *offset, *bytes, pad)) {