[Ocfs2-tools-devel] [PATCH 13/44] libocfs2: Add CoW support.

[Joel Becker]

On Mon, Dec 28, 2009 at 05:00:58PM +0800, Tao Ma wrote:
> This patch try CoW support for a refcounted record.
> 
> the whole process will be:
> 1. Calculate how many clusters we need to CoW and where we start.
>    Extents that are not completely encompassed by the write will
>    be broken on 1MB boundaries.
> 2. Do CoW for the clusters.
> 3. Change the b-tree structure with the new allocated clusters.
> 
> If the old extent has refcount=1, just remove the refcounted flag
> and it is OK.

	This looks like a pretty straightforward copy of the kernel
infrastructure.

Joel

-- 

"Every new beginning comes from some other beginning's end."

Joel Becker
Principal Software Developer
Oracle
E-mail: joel.becker at oracle.com
Phone: (650) 506-8127