On Fri, Oct 06, 2006 at 06:17:12PM -0700, Joseph Mocker wrote: > David Dyer-Bennet's post gives a hint of how this could be done without > any API. Simply augment a few system calls like open(), unlink(), etc. > Calls that can potentially change files. Since you can't change a file > unless is open()'ed with various write flags like O_WRONLY, O_RDWR, etc, > this could be an ideal place to create the version.
I wrote about the same thing. These are but heuristics. > One could probably write a "poor man's" FV LD_PRELOAD library to do this > without the filesystem's knowledge at all. Indeed, and I believe it has been done before (search freshmeat.net). > It wouldn't be as efficient with space as could be done at the > filesystem level, but as someone said, disk is cheap. Suppose ZFS gave you a primitive for efficiently "snapshotting" individual files, rather than entire filesystems. That's the primitive you'd need to implement this LD_PRELOADable object space efficiently. Nico -- _______________________________________________ zfs-discuss mailing list zfs-discuss@opensolaris.org http://mail.opensolaris.org/mailman/listinfo/zfs-discuss
