On 09/13/2011 12:49 PM, Alex Bligh wrote: > For instance, Paul's suggestion on setting 'rotational' using /proc > instead is definitely better than the way nbd-client does it at the > moment.
That can go in later, right? >> - Make NBD_CMD_TRIM cause nbd-server to call fallocate() with >> FALLOC_FL_PUNCH_HOLE. > > We need to be a bit careful on these. IIRC (someone please check!) > on Linux fallocate() is an extended call that supports various stuff, > whereas posix_fallocate() is the normal POSIX call, and that doesn't > support PUNCH_HOLE. On non-Linux systems, fallocate() is the normal > POSIX call. No, it's really called posix_fallocate elsewhere. Non-Linux system might alias fallocate and posix_fallocate, but the name in POSIX is really posix_fallocate. Of course, non-Linux systems will never have FALLOC_FL_PUNCH_HOLE, so we can assume that defined(FALLOC_FL_PUNCH_HOLE)<=>fallocate has Linux semantics. > I /think/ we can just see if FALLOC_FL_PUNCH_HOLE is defined, > and if so, make the call, and ignore the error condition. That > way if compiled on box X and run on box Y it will still be OK. > However, I think we ought to have a config option to turn it off. Right now it is opt-in, via --trim. However, flush/fua should likely _not_ be opt-in, because they are required for safety. Paolo ------------------------------------------------------------------------------ BlackBerry® DevCon Americas, Oct. 18-20, San Francisco, CA Learn about the latest advances in developing for the BlackBerry® mobile platform with sessions, labs & more. See new tools and technologies. Register for BlackBerry® DevCon today! http://p.sf.net/sfu/rim-devcon-copy1 _______________________________________________ Nbd-general mailing list [email protected] https://lists.sourceforge.net/lists/listinfo/nbd-general
