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=-3.8 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,UNPARSEABLE_RELAY,USER_AGENT_GIT 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 8A61AC3F2CE for ; Tue, 17 Mar 2020 15:11:21 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 5D6C220757 for ; Tue, 17 Mar 2020 15:11:21 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726754AbgCQPLU (ORCPT ); Tue, 17 Mar 2020 11:11:20 -0400 Received: from bhuna.collabora.co.uk ([46.235.227.227]:33846 "EHLO bhuna.collabora.co.uk" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726478AbgCQPLU (ORCPT ); Tue, 17 Mar 2020 11:11:20 -0400 Received: from [127.0.0.1] (localhost [127.0.0.1]) (Authenticated sender: andrzej.p) with ESMTPSA id 4A3E4290AC2 From: Andrzej Pietrasiewicz To: linux-block@vger.kernel.org Cc: Jens Axboe , kernel@collabora.com, andrzej.p@collabora.com Subject: [PATCH 0/2] loop: Better discard support for block devices Date: Tue, 17 Mar 2020 16:11:09 +0100 Message-Id: <20200317151111.25749-1-andrzej.p@collabora.com> X-Mailer: git-send-email 2.17.1 Sender: linux-block-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-block@vger.kernel.org This is a respin of the series from Evan, after rebasing it on a current tree (v5.6-rc6). In the current upstream tree there already is code which differentiates between REQ_OP_DISCARD and REQ_OP_WRITE_ZEROS. Since applying the second patch required dropping some code inside it, I have also dropped the A-b/R-b tags. Below is the cover letter of the previous iteration of the series: This series addresses some errors seen when using the loop device directly backed by a block device. The first change plumbs out the correct error message, and the second change prevents the error from occurring in many cases. The errors look like this: [ 90.880875] print_req_error: I/O error, dev loop5, sector 0 The errors occur when trying to do a discard or write zeroes operation on a loop device backed by a block device that does not support write zeroes. Firstly, the error itself is incorrectly reported as I/O error, but is actually EOPNOTSUPP. The first patch plumbs out EOPNOTSUPP to properly report the error. The second patch prevents these errors from occurring by mirroring the zeroing capabilities of the underlying block device into the loop device. Before this change, discard was always reported as being supported, and the loop device simply turns around and does an fallocate operation on the backing device. After this change, backing block devices that do support zeroing will continue to work as before, and continue to get all the benefits of doing that. Backing devices that do not support zeroing will fail earlier, avoiding hitting the loop device at all and ultimately avoiding this error in the logs. I can also confirm that this fixes test block/003 in the blktests, when running blktests on a loop device backed by a block device. Changes in v5: - Don't mirror discard if lo_encrypt_key_size is non-zero (Gwendal) Changes in v4: - Mirror blkdev's write_zeroes into loopdev's discard_sectors. Changes in v3: - Updated tags - Updated commit description Changes in v2: - Unnested error if statement (Bart) Evan Green (2): loop: Report EOPNOTSUPP properly loop: Better discard support for block devices drivers/block/loop.c | 51 +++++++++++++++++++++++++++++++++----------- 1 file changed, 38 insertions(+), 13 deletions(-) -- 2.17.1