From a2486a266d8df715349ec0e325d0bedc0bdc0557 Mon Sep 17 00:00:00 2001 From: John Snow Date: Wed, 10 May 2017 13:39:45 -0400 Subject: [PATCH 05/15] blockdev: use drained_begin/end for qmp_block_resize Fixes: https://bugzilla.redhat.com/show_bug.cgi?id=1447551 If one tries to issue a block_resize while a guest is busy accessing the disk, it is possible that qemu may deadlock when invoking aio_poll from both the main loop and the iothread. Replace another instance of bdrv_drain_all that doesn't quite belong. Cc: qemu-stable@nongnu.org Suggested-by: Paolo Bonzini Signed-off-by: John Snow Reviewed-by: Eric Blake Reviewed-by: Paolo Bonzini Signed-off-by: Kevin Wolf --- blockdev.c | 5 ++--- 1 file changed, 2 insertions(+), 3 deletions(-) diff --git a/blockdev.c b/blockdev.c index 43818dade1..d8ff508eff 100644 --- a/blockdev.c +++ b/blockdev.c @@ -2929,10 +2929,9 @@ void qmp_block_resize(bool has_device, const char *device, goto out; } - /* complete all in-flight operations before resizing the device */ - bdrv_drain_all(); - + bdrv_drained_begin(bs); ret = blk_truncate(blk, size); + bdrv_drained_end(bs); switch (ret) { case 0: break; -- 2.11.0