--On 16 September 2011 11:26:53 +0200 Wouter Verhelst <[email protected]> wrote:
>> I think you can use debugfs's dump_extents command (from memory). > > Yes, but that requires an unmounted filesystem. If I want to add this to > the test suite, that's not going to work. Format a file as an ext4 file system. Loopback mount it. Put your test disk in there as a file. Do your stuff. Unmount it. Check it. The loopback mount requires root privileges, but the alternative is to use the syscall (can't remember). I think that needs root privs anyway, and won't work if someone is running on a different file system (who knows is tmpfs supports PUNCH_HOLE). A heuristic way would be: * create the file non-sparse with dd from /dev/zero * run tests * run du, and check it is significantly smaller (du reports actual file space taken, in contrast to stat()). That's only going to work on file systems that support files. -- Alex Bligh ------------------------------------------------------------------------------ BlackBerry® DevCon Americas, Oct. 18-20, San Francisco, CA http://p.sf.net/sfu/rim-devcon-copy2 _______________________________________________ Nbd-general mailing list [email protected] https://lists.sourceforge.net/lists/listinfo/nbd-general
