debian/patches/extra/0005-blockdev-use-drained_begin-end-for-qmp_block_resize.patch

   1 From a2486a266d8df715349ec0e325d0bedc0bdc0557 Mon Sep 17 00:00:00 2001
   2 From: John Snow <jsnow@redhat.com>
   3 Date: Wed, 10 May 2017 13:39:45 -0400
   4 Subject: [PATCH 05/15] blockdev: use drained_begin/end for qmp_block_resize
   5
   6 Fixes: https://bugzilla.redhat.com/show_bug.cgi?id=1447551
   7
   8 If one tries to issue a block_resize while a guest is busy
   9 accessing the disk, it is possible that qemu may deadlock
  10 when invoking aio_poll from both the main loop and the iothread.
  11
  12 Replace another instance of bdrv_drain_all that doesn't
  13 quite belong.
  14
  15 Cc: qemu-stable@nongnu.org
  16 Suggested-by: Paolo Bonzini <pbonzini@redhat.com>
  17 Signed-off-by: John Snow <jsnow@redhat.com>
  18 Reviewed-by: Eric Blake <eblake@redhat.com>
  19 Reviewed-by: Paolo Bonzini <pbonzini@redhat.com>
  20 Signed-off-by: Kevin Wolf <kwolf@redhat.com>
  21 ---
  22  blockdev.c | 5 ++---
  23  1 file changed, 2 insertions(+), 3 deletions(-)
  24
  25 diff --git a/blockdev.c b/blockdev.c
  26 index 43818dade1..d8ff508eff 100644
  27 --- a/blockdev.c
  28 +++ b/blockdev.c
  29 @@ -2929,10 +2929,9 @@ void qmp_block_resize(bool has_device, const char *device,
  30          goto out;
  31      }
  32
  33 -    /* complete all in-flight operations before resizing the device */
  34 -    bdrv_drain_all();
  35 -
  36 +    bdrv_drained_begin(bs);
  37      ret = blk_truncate(blk, size);
  38 +    bdrv_drained_end(bs);
  39      switch (ret) {
  40      case 0:
  41          break;
  42 --
  43 2.11.0
  44