From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-1.0 required=3.0 tests=MAILING_LIST_MULTI, SPF_HELO_NONE,SPF_PASS autolearn=no autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id DB03DC2BA19 for ; Tue, 21 Apr 2020 23:15:59 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id A675A206D5 for ; Tue, 21 Apr 2020 23:15:59 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726160AbgDUXP7 convert rfc822-to-8bit (ORCPT ); Tue, 21 Apr 2020 19:15:59 -0400 Received: from mail.kernel.org ([198.145.29.99]:45380 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726039AbgDUXP7 (ORCPT ); Tue, 21 Apr 2020 19:15:59 -0400 From: bugzilla-daemon@bugzilla.kernel.org To: linux-ext4@vger.kernel.org Subject: [Bug 207367] Accraid / aptec / Microsemi / ext4 / larger then 16TB Date: Tue, 21 Apr 2020 23:15:58 +0000 X-Bugzilla-Reason: None X-Bugzilla-Type: changed X-Bugzilla-Watch-Reason: AssignedTo fs_ext4@kernel-bugs.osdl.org X-Bugzilla-Product: File System X-Bugzilla-Component: ext4 X-Bugzilla-Version: 2.5 X-Bugzilla-Keywords: X-Bugzilla-Severity: normal X-Bugzilla-Who: tytso@mit.edu X-Bugzilla-Status: NEW X-Bugzilla-Resolution: X-Bugzilla-Priority: P1 X-Bugzilla-Assigned-To: fs_ext4@kernel-bugs.osdl.org X-Bugzilla-Flags: X-Bugzilla-Changed-Fields: Message-ID: In-Reply-To: References: Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: 8BIT X-Bugzilla-URL: https://bugzilla.kernel.org/ Auto-Submitted: auto-generated MIME-Version: 1.0 Sender: linux-ext4-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-ext4@vger.kernel.org https://bugzilla.kernel.org/show_bug.cgi?id=207367 --- Comment #13 from Theodore Tso (tytso@mit.edu) --- On Tue, Apr 21, 2020 at 09:45:54AM -0700, Christoph Hellwig wrote: > On Tue, Apr 21, 2020 at 06:29:10PM +0200, Jan Kara wrote: > > Well, there are two problems with this - firstly, ocfs2 is also using jbd2 > > and it knows nothing about iomap. So that would have to be implemented. > > Secondly, you have to somehow pass iomap ops to jbd2 so it all boils down > > to passing some callback to jbd2 during journal init to map blocks anyway > > as Dave said. And then it is upto filesystem to do the mapping - usually > > directly using its internal block mapping function - so no need for iomap > > AFAICT. > > You'll need to describe the mapping some how. So why not reuse an > existing mechanism instead of creating a new ad-hoc one? Well, we could argue that bmap() is an "existing mechanism" --- again, bmap() returns a u64, so it's perfectly fine. It's FIBMAP which is "fundamentally broken", not bmap(). If the goal is to eventually eliminate bmap() and aops->bmap(), sure, then we should force march all file systems to use iomap_bmap(), including ocfs2. Otherwise, if the goal alert users of FIBMAP when it's returning an corrutped block number, why not move the check if the block is larger than INT_MAX to ioctl_fibmap() in fs/ioctl.c, instead of in iomap_bmap()? If we can't fix this, I'm beginning to think that switching to iomap for fiemap and bmap is actually a lose for ext4. It's causing performance regressions, and now we see it's causing functionality regressions. Sure, it's saving a bit of code size, but is it really worth it to use iomap for fiemap/bmap? - Ted -- You are receiving this mail because: You are watching the assignee of the bug.