On Wed, Jun 16, 2010 at 02:57:01PM +0800, jeff.liu wrote:
> Paul Eggert wrote:
> > For example, if a fiemap_extent has the FIEMAP_EXTENT_UNWRITTEN flag
> > set, cp should treat that as a hole, because the extent is all zeros.
> > (This will greatly help performance in some cases.) Also, if an input
> > extent is read and a block of it is found to be zeros, cp should skip
> > over that block when writing.
> If FIEMAP_EXTENT_UNWRITTEN flag is set, we can call fallocate(2) against the
> dest file directly for
> the performance boost.
Nope. An UNWRITTEN extent is a hole, and the user asked for
holes. If cp sees an UNWRITTEN extent it is skipped.
Joel
--
"Friends may come and go, but enemies accumulate."
- Thomas Jones
Joel Becker
Principal Software Developer
Oracle
E-mail: [email protected]
Phone: (650) 506-8127
