Re: possible circular locking dependency detected

On Fri, Sep 02, 2016 at 10:12:08AM -0700, Linus Torvalds wrote:

On Fri, Sep 2, 2016 at 10:02 AM, Al Viro [off-list ref] wrote:

quoted

It's very much _not_ just overlayfs being pathological - that it certainly is,
but the problem is much wider.

Al, can you take a look at my two patches, and see if you agree that
they fix it, though?

AFAICS, they should.  Locking is obviously saner that way and AFAICS the
rest is absolutely straightforward.

Acked-by: Al Viro <viro@zeniv.linux.org.uk>

Of course, we now have *another* splice deadlock. That pipe inode is
nasty, it's very easy to deadlock on it in subtle ways.

I'm still digging through iomap.c, but that's better taken to another branch
of this thread...