[Ocfs2-devel] [PATCH 03/15] xfs: zero posteof blocks when cloning above eof

[Christoph Hellwig]

On Thu, Oct 04, 2018 at 05:44:54PM -0700, Darrick J. Wong wrote:
> From: Darrick J. Wong <darrick.wong at oracle.com>
> 
> When we're reflinking between two files and the destination file range
> is well beyond the destination file's EOF marker, zero any posteof
> speculative preallocations in the destination file so that we don't
> expose stale disk contents.  The previous strategy of trying to clear
> the preallocations does not work if the destination file has the
> PREALLOC flag set.

But I think we should still drop speculative delalloc preallocations 
instead of zeroing them in addition to zeroing of any real blocks in
the data fork.