Re: [ext4 io hang] buffered write io hang in balance_dirty_pages

Matthew Wilcox
2023-04-27T03:58:47Z

On Thu, Apr 27, 2023 at 10:20:28AM +0800, Ming Lei wrote:
> Hello Guys,
>
> I got one report in which buffered write IO hangs in balance_dirty_pages,
> after one nvme block device is unplugged physically, then umount can't
> succeed.

That's a feature, not a bug ... the dd should continue indefinitely?

balance_dirty_pages() is sleeping in KILLABLE state, so kill -9 of
the dd process should succeed.