On Tue, Oct 29, 2013 at 06:07:21AM -0700, Christoph Hellwig wrote: > On Tue, Oct 29, 2013 at 09:00:48AM -0400, Anna Schumaker wrote: > > From what I can tell, I think the allocated flag will just tell the > > clients if all the blocks exist on disk or not. Is there a way to have > > a hole with allocated blocks? Or maybe it's supposed to represent > > partially allocated blocks? I checked the draft, and it doesn't > > actually say what they expect allocated to represent... > > You can have preallocated space, which behaves like a hole in that > reads return zeroes. As far as SEEK_DATA/SEEK_HOLE is concerned we > tend to treat them as holes when we can as that's what the users expect. > > Note that at least the pnfs block rfc has a special state representing > this kind of preallocated space. http://tools.ietf.org/html/draft-ietf-nfsv4-minorversion2-20#section-5.2 E.g. "Hole: A byte range within a Sparse file that contains regions of all zeroes. For block-based file systems, this could also be an unallocated region of the file." So it sounds like a hole can either be allocated or not, which seems to agree with what you expect? I haven't read these parts of the spec yet at all.... --b. -- To unsubscribe from this list: send the line "unsubscribe linux-nfs" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
