block: Check for inserted BlockDriverState in blk_io_limits_disable()

When you set I/O limits using block_set_io_throttle or the command
line throttling.* options they are kept in the BlockBackend regardless
of whether a BlockDriverState is attached to the backend or not.

Therefore when removing the limits using blk_io_limits_disable() we
need to check if there's a BDS before attempting to drain it, else it
will crash QEMU. This can be reproduced very easily using HMP:

     (qemu) drive_add 0 if=none,throttling.iops-total=5000
     (qemu) drive_del none0

Reported-by: sochin jiang <sochin.jiang@huawei.com>
Signed-off-by: Alberto Garcia <berto@igalia.com>
Reviewed-by: Max Reitz <mreitz@redhat.com>
Message-id: 0d3a67ce8d948bb33e08672564714dcfb76a3d8c.1510339534.git.berto@igalia.com
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
master
Alberto Garcia 2017-11-10 20:54:46 +02:00 committed by Stefan Hajnoczi
parent dc868fb03b
commit 48bf7ea81a
1 changed files with 10 additions and 4 deletions

View File

@ -1980,10 +1980,16 @@ void blk_set_io_limits(BlockBackend *blk, ThrottleConfig *cfg)
void blk_io_limits_disable(BlockBackend *blk)
{
assert(blk->public.throttle_group_member.throttle_state);
bdrv_drained_begin(blk_bs(blk));
throttle_group_unregister_tgm(&blk->public.throttle_group_member);
bdrv_drained_end(blk_bs(blk));
BlockDriverState *bs = blk_bs(blk);
ThrottleGroupMember *tgm = &blk->public.throttle_group_member;
assert(tgm->throttle_state);
if (bs) {
bdrv_drained_begin(bs);
}
throttle_group_unregister_tgm(tgm);
if (bs) {
bdrv_drained_end(bs);
}
}
/* should be called before blk_set_io_limits if a limit is set */