On Tue, Sep 21, 2021 at 10:44:31AM +1000, Dave Chinner wrote: > I think this wants to be a behavioural modifier for existing > operations rather than an operation unto itself. i.e. similar to how > KEEP_SIZE modifies ALLOC behaviour but doesn't fundamentally alter > the guarantees ALLOC provides userspace. > > In this case, the change of behaviour over ZERO_RANGE is that we > want physical zeros to be written instead of the filesystem > optimising away the physical zeros by manipulating the layout > of the file. Yes. > Then we have and API that looks like: > > ALLOC - allocate space efficiently > ALLOC | INIT - allocate space by writing zeros to it > ZERO - zero data and preallocate space efficiently > ZERO | INIT - zero range by writing zeros to it > > Which seems to cater for all the cases I know of where physically > writing zeros instead of allocating unwritten extents is the > preferred behaviour of fallocate().... Agreed. I'm not sure INIT is really the right name, but I can't come up with a better idea offhand.
