Re: [PATCH] xfs: Fix WARN_ON(delalloc) in xfs_vm_releasepage()

Ben Myers
2013-03-22T21:12:22Z

On Thu, Mar 21, 2013 at 12:37:33PM +1100, Dave Chinner wrote:
> On Fri, Mar 15, 2013 at 03:52:14PM -0500, Ben Myers wrote:
> > Hi Jan,
> >
> > On Thu, Mar 14, 2013 at 02:30:54PM +0100, Jan Kara wrote:
> > > When a dirty page is truncated from a file but reclaim gets to it before
> > > truncate_inode_pages(), we hit WARN_ON(delalloc) in
> > > xfs_vm_releasepage(). This is because reclaim tries to write the page,
> > > xfs_vm_writepage() just bails out (leaving page clean) and thus reclaim
> > > thinks it can continue and calls xfs_vm_releasepage() on page with dirty
> > > buffers.
> > >
> > > Fix the issue by redirtying the page in xfs_vm_writepage(). This makes
> > > reclaim stop reclaiming the page and also logically it keeps page in a
> > > more consistent state where page with dirty buffers has PageDirty set.
> >
> > Was there an easy way to reproduce this? I'm testing and reviewing this now
> > and it might help.
>
> This patch has been confirmed to fix the report generated by
> the DB workload I mentioned in another part of the thread. Hence I
> think it should be good to go.

Agreed, Thanks.

-Ben