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

[Dave Chinner]

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.

Cheers,

Dave.
-- 
Dave Chinner
david at fromorbit.com