Re: [PATCH] Btrfs: fix truncate down when no_holes feature is enabled

[Liu Bo <bo.li.liu@oracle.com>]

On Tue, Nov 22, 2016 at 02:13:21PM -0500, Chris Mason wrote:
> On 11/11/2016 05:27 PM, Liu Bo wrote:
> > For such a file mapping,
> > 
> > [0-4k][hole][8k-12k]
> > 
> > In NO_HOLES mode, we don't have the [hole] extent any more.
> > Commit c1aa45759e90 ("Btrfs: fix shrinking truncate when the no_holes feature is enabled")
> >  fixed disk isize not being updated in NO_HOLES mode when data is not flushed.
> > 
> > However, even if data has been flushed, we can still have trouble
> > in updating disk isize since we updated disk isize to 'start' of
> > the last evicted extent.
> > 
> > Also add a ASSERT for better catching (for developers only).
> > 
> > Signed-off-by: Liu Bo <bo.li.liu@oracle.com>
> 
> Thanks Liu!
> 
> Reviewed-by: Chris Mason <clm@fb.com>

The added ASSERT() can cause generic/068 to crash because I didn't
filter out the 'log tree' case, I'm testing a V2 patch.

Thanks,

-liubo