On Tue, May 10, 2016 at 03:19:52PM +0800, Qu Wenruo wrote: > Hi, Chris, Josef and David, > > As merge window for v4.7 is coming, it would be good to hear your > ideas about the inband dedupe. > > We are addressing the ENOSPC problem which Josef pointed out, and we > believe the final fix patch would come out at the beginning of the > merge window.(Next week)
How about the fiemap performance problem you referenced before? My guess is that it happens because you don't coalesce writes into anything larger than a page so you're stuck deduping at some silly size like 4k. This in turn fragments the files so much that fiemap has a hard time walking backrefs. I have to check the patches to be sure but perhaps you can tell me whether my hunch is correct or not. In fact, I actually asked privately for time to review your dedupe patches, but I've been literally so busy cleaning up after the mess you left in your last qgroups rewrite I haven't had time. You literally broke qgroups in almost every spot that matters. In some cases (drop_snapshot) you tore out working code and left in a /* TODO */ comment for someone else to complete. Snapshot create was so trivially and completely broken by your changes that weeks later, I'm still hunting a solution which doesn't involve adding an extra _commit_ to our commit. This is a MASSIVE regression from where we were before. IMHO, you should not be trusted with large features or rewrites until you can demonstrate: - A willingness to *completely* solve the problem you are trying to 'fix', not do half the job which someone else will have to complete for you. - Actual testing. The snapshot bug I reference above exists purely because nobody created a snapshot inside of one and checked the qgroup numbers! Sorry to be so harsh. --Mark -- Mark Fasheh -- To unsubscribe from this list: send the line "unsubscribe linux-btrfs" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
