On Fri, Jan 24, 2014 at 12:49:18PM +0000, Pádraig Brady wrote: > On 01/24/2014 03:56 AM, Rodrigo Campos wrote: > > On Fri, Jan 24, 2014 at 03:30:20AM +0000, Pádraig Brady wrote: > >> On 01/24/2014 03:12 AM, Rodrigo Campos wrote: > >>> On Fri, Jan 24, 2014 at 02:59:41AM +0000, Pádraig Brady wrote: > >>>> On 01/24/2014 02:41 AM, Rodrigo Campos wrote: > >>>>> On Fri, Jan 24, 2014 at 01:07:21AM +0000, Pádraig Brady wrote: > >>>>>> On 01/24/2014 12:47 AM, Bernhard Voelker wrote: > >>>>>>> Inspired by a recent post on util-linux ML [1], talking about turning > >>>>>>> a file into a sparse file in-place, i.e. not using a 2-step approach > >>>>>>> like `cp --sparse file file2 && mv file2 file`), I thought, hey, don't > >>>>>>> we have this in coreutils already? > > > But it's just a matter of policy. Do you know what the policy is ? > > We use system specific functionality where appropriate. > We would just decide what to do when the current > file doesn't support punch hole (which we have to do anyway as said above). > Do we fail or ignore. Generally sparse requests are advisory, > and indeed in dd we already quietly disable sparse mode if not supported. > So we would do the same if punch hole was not supported on the dest.
Ohh, okay! > >> If there are other methods to punch a hole in a file > >> on other systems, they can be added as an option to coreutils > >> without changing the interface. > > > > AFAIK, there aren't. And, as I said, is not linux specific only, it also is > > fs > > specific. > > There is fcntl(F_FREESP) on solaris, with mention of porting that to FREEBSD. Ohh, nice. I didn't know about them! > > If I have to guess, this flag is like other useful flags linux adds and most > > other platforms don't. So you are exposing a feature here, that will only > > will > > work on linux with certain filesystems. Probably there is a policy already > > esablished for this ? (I mean, if it's ok or not) > > If there is a sensible fall back, then it's OK to use non ubiquitous > interfaces. Great! Thanks a lot, and sorry for all the emails :) Rodrigo
