From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from bombadil.infradead.org ([65.50.211.133]:34754 "EHLO bombadil.infradead.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755632AbdJRHbG (ORCPT ); Wed, 18 Oct 2017 03:31:06 -0400 Date: Wed, 18 Oct 2017 00:31:04 -0700 From: Christoph Hellwig Subject: Re: agcount for 2TB, 4TB and 8TB drives Message-ID: <20171018073104.GA6274@infradead.org> References: <1b5b6410-b1d9-8519-7032-8ea0ca46f5b5@scylladb.com> <20171009112306.GM3666@dastard> <89a7ae9a-9960-ae37-f6ca-0c1f2e33f65f@scylladb.com> <20171009220332.GP3666@dastard> <38bd7785-174d-fd09-fc1f-50a2d4e1dd69@scylladb.com> <20171010225524.GV3666@dastard> <86635b89-5016-5cd1-53a2-bf21b842ae04@scylladb.com> <20171014224224.GD15067@dastard> <20171015220018.GG3666@dastard> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20171015220018.GG3666@dastard> Sender: linux-xfs-owner@vger.kernel.org List-ID: List-Id: xfs To: Dave Chinner Cc: Avi Kivity , Eric Sandeen , "Darrick J. Wong" , Gandalf Corvotempesta , linux-xfs@vger.kernel.org On Mon, Oct 16, 2017 at 09:00:19AM +1100, Dave Chinner wrote: > fallocate will block *all* IO and mmap faults on that file, not just > the ones that require allocation. fallocate creates a complete IO > submission pipeline stall, punting all new IO submissions to the > background worker where they will block until fallocate completes. Not sure if it helps Avis case, but I think we could relax the fallocate exclusive i_rwsem requirement a bit, similar to direct I/O writes. Basically as long as your fallocate is block aligned we should be fine with a shared iolock for the "normal" allocating fallocate (discounting things like hole punches and extent shifts of course).