Re: [PATCH 2/2] generic: test I/O on dm error device

Dave Chinner
2016-03-15T02:46:32Z

On Fri, Mar 11, 2016 at 11:40:22PM +0800, Eryu Guan wrote:
> This is a test that performs simple I/O on dm error device, which
> returns EIO on all I/O request.
>
> This is motivated by an ext4 bug that crashes kernel on error path when
> trying to update atime. Following kernel patch should fix the issue
>
> ext4: fix NULL pointer dereference in ext4_mark_inode_dirty()

Why does this test require the loop device? Why can't you just
unmount the filesystem, run 'blkdev --flushbufs <dev>' to ensure
there are no cached buffers/pages on the block device, then mount
it again?

Cheers,

Dave.
--
Dave Chinner
david@fromorbit.com