xfs_file_splice_read: possible circular locking dependency detected

[CAI Qian]

----- Original Message -----
> From: "Dave Chinner" <david at fromorbit.com>
> To: "CAI Qian" <caiqian at redhat.com>
> Cc: "linux-xfs" <linux-xfs at vger.kernel.org>, "Linus Torvalds" <torvalds at linux-foundation.org>, "Al Viro"
> <viro at zeniv.linux.org.uk>, xfs at oss.sgi.com
> Sent: Friday, September 2, 2016 8:39:19 PM
> Subject: Re: xfs_file_splice_read: possible circular locking dependency detected
> 
> On Fri, Sep 02, 2016 at 01:02:16PM -0400, CAI Qian wrote:
> > Spice seems start to deadlock using the reproducer,
> > 
> > https://github.com/linux-test-project/ltp/blob/master/testcases/kernel/syscalls/splice/splice01.c
> > 
> > This seems introduced recently after v4.8-rc3 or -rc4, so suspect this xfs
> > update was one to blame,
> > 
> > 7d1ce606a37922879cbe40a6122047827105a332
> 
> Nope, this goes back to the splice rework back around ~3.16, IIRC.
Right. FYI, revert the commit below fixes the regression,

8d02076 : ->splice_write() via ->write_iter()

   CAI Qian