On Thu, Aug 25, 2011 at 02:06:32AM -0400, Christoph Hellwig wrote: > On Tue, Jun 28, 2011 at 11:33:19AM -0400, Josef Bacik wrote: > > This is a test to make sure seek_data/seek_hole is acting like it does on > > Solaris. It will check to see if the fs supports finding a hole or not and will > > adjust as necessary. > > Can you resend this with any updates that happened in the meantime? > > Dave also still had some comments about semantics, so it might be worth > to incorporate that as well. The main questions I had when looking at this was how we should handle unwritten extents - the only answer I got was along the lines of "we'll deal with that once filesystems have implemented something". That's a bit of a chicken-and-egg situation, and doesn't help me decide what is the best thing to do. I don't want to have to re-implement this code when it's decided i did the wrong thing initially. The most basic question I really want answered is this: - is preallocated space a HOLE, or is it DATA? Whatever the answer, I think it should be consistently presented by all filesystems that support preallocation, and it should be encoded into the generic SEEK_HOLE/SEEK_DATA tests.... Answering that question then helps answer the more complex questions I had, like: - what does SEEK_DATA return when you have a file layout like "hole-prealloc-data"? Answers to that sort of question need to be known so we can write corner-case tests to correctly verify the filesystem implementation. I like to do better than present userspace with an interface that behaves vastly different depending on the underlying filesystem, but if the answer is "definition and implementation is entirely filesystem specific" then I'll just go make something up.... Cheers, Dave. -- Dave Chinner david@xxxxxxxxxxxxx -- To unsubscribe from this list: send the line "unsubscribe linux-fsdevel" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
