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=-9.8 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI, SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,USER_AGENT_GIT autolearn=unavailable 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 BF0C9C83004 for ; Tue, 28 Apr 2020 18:30:09 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 9D99B214D8 for ; Tue, 28 Apr 2020 18:30:09 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1588098609; bh=3AjzAH6sCRBBQIALkZlA3mWNYY6eXAlOgczOsfvavPY=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=FlKGHV4rmXhCjYkGhI7V7iQlhD+XHnbczr3PMLJZ9AXIw3mk1qQuEziH/eXqMbrWr 6XbOLK8lm2k2Ghb8dHRYUj16wYf00D+U2es99ZhGys7qlDFHp2v5ugP0STEKhxKwku oyUJD4N9jw3NR3iyjCKRsH4WjR2LzdN6GI+Pf9nM= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1729461AbgD1SaI (ORCPT ); Tue, 28 Apr 2020 14:30:08 -0400 Received: from mail.kernel.org ([198.145.29.99]:44216 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1729432AbgD1SaA (ORCPT ); Tue, 28 Apr 2020 14:30:00 -0400 Received: from localhost (83-86-89-107.cable.dynamic.v4.ziggo.nl [83.86.89.107]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id 98E262137B; Tue, 28 Apr 2020 18:29:59 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1588098600; bh=3AjzAH6sCRBBQIALkZlA3mWNYY6eXAlOgczOsfvavPY=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=wyzmHccbIzHrgF62wuLi20hYOU1ixxfqG3Lt4Y3VzL52USZc0tPKqxGDf9ebbQUod fh6HtVwYfJJbr3HjLugrEaksv5pjTdINYHn3udEKzEWZHYyu+gzUiasACFV6V5rp6Z YHUnrJ8HoBptLgmpxDViGwwWSdgmdRS/rGBfae+E= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Evan Green , Gwendal Grignou , Chaitanya Kulkarni , Andrzej Pietrasiewicz , Christoph Hellwig , Jens Axboe , Sasha Levin Subject: [PATCH 4.19 025/131] loop: Better discard support for block devices Date: Tue, 28 Apr 2020 20:23:57 +0200 Message-Id: <20200428182228.298249436@linuxfoundation.org> X-Mailer: git-send-email 2.26.2 In-Reply-To: <20200428182224.822179290@linuxfoundation.org> References: <20200428182224.822179290@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Evan Green [ Upstream commit c52abf563049e787c1341cdf15c7dbe1bfbc951b ] If the backing device for a loop device is itself a block device, then mirror the "write zeroes" capabilities of the underlying block device into the loop device. Copy this capability into both max_write_zeroes_sectors and max_discard_sectors of the loop device. The reason for this is that REQ_OP_DISCARD on a loop device translates into blkdev_issue_zeroout(), rather than blkdev_issue_discard(). This presents a consistent interface for loop devices (that discarded data is zeroed), regardless of the backing device type of the loop device. There should be no behavior change for loop devices backed by regular files. This change fixes blktest block/003, and removes an extraneous error print in block/013 when testing on a loop device backed by a block device that does not support discard. Signed-off-by: Evan Green Reviewed-by: Gwendal Grignou Reviewed-by: Chaitanya Kulkarni [used updated version of Evan's comment in loop_config_discard()] [moved backingq to local scope, removed redundant braces] Signed-off-by: Andrzej Pietrasiewicz Reviewed-by: Christoph Hellwig Signed-off-by: Jens Axboe Signed-off-by: Sasha Levin --- drivers/block/loop.c | 42 +++++++++++++++++++++++++++++++----------- 1 file changed, 31 insertions(+), 11 deletions(-) diff --git a/drivers/block/loop.c b/drivers/block/loop.c index 9cd231a27328e..c1341c86bcded 100644 --- a/drivers/block/loop.c +++ b/drivers/block/loop.c @@ -426,11 +426,12 @@ static int lo_fallocate(struct loop_device *lo, struct request *rq, loff_t pos, * information. */ struct file *file = lo->lo_backing_file; + struct request_queue *q = lo->lo_queue; int ret; mode |= FALLOC_FL_KEEP_SIZE; - if ((!file->f_op->fallocate) || lo->lo_encrypt_key_size) { + if (!blk_queue_discard(q)) { ret = -EOPNOTSUPP; goto out; } @@ -864,28 +865,47 @@ static void loop_config_discard(struct loop_device *lo) struct inode *inode = file->f_mapping->host; struct request_queue *q = lo->lo_queue; + /* + * If the backing device is a block device, mirror its zeroing + * capability. Set the discard sectors to the block device's zeroing + * capabilities because loop discards result in blkdev_issue_zeroout(), + * not blkdev_issue_discard(). This maintains consistent behavior with + * file-backed loop devices: discarded regions read back as zero. + */ + if (S_ISBLK(inode->i_mode) && !lo->lo_encrypt_key_size) { + struct request_queue *backingq; + + backingq = bdev_get_queue(inode->i_bdev); + blk_queue_max_discard_sectors(q, + backingq->limits.max_write_zeroes_sectors); + + blk_queue_max_write_zeroes_sectors(q, + backingq->limits.max_write_zeroes_sectors); + /* * We use punch hole to reclaim the free space used by the * image a.k.a. discard. However we do not support discard if * encryption is enabled, because it may give an attacker * useful information. */ - if ((!file->f_op->fallocate) || - lo->lo_encrypt_key_size) { + } else if (!file->f_op->fallocate || lo->lo_encrypt_key_size) { q->limits.discard_granularity = 0; q->limits.discard_alignment = 0; blk_queue_max_discard_sectors(q, 0); blk_queue_max_write_zeroes_sectors(q, 0); - blk_queue_flag_clear(QUEUE_FLAG_DISCARD, q); - return; - } - q->limits.discard_granularity = inode->i_sb->s_blocksize; - q->limits.discard_alignment = 0; + } else { + q->limits.discard_granularity = inode->i_sb->s_blocksize; + q->limits.discard_alignment = 0; - blk_queue_max_discard_sectors(q, UINT_MAX >> 9); - blk_queue_max_write_zeroes_sectors(q, UINT_MAX >> 9); - blk_queue_flag_set(QUEUE_FLAG_DISCARD, q); + blk_queue_max_discard_sectors(q, UINT_MAX >> 9); + blk_queue_max_write_zeroes_sectors(q, UINT_MAX >> 9); + } + + if (q->limits.max_write_zeroes_sectors) + blk_queue_flag_set(QUEUE_FLAG_DISCARD, q); + else + blk_queue_flag_clear(QUEUE_FLAG_DISCARD, q); } static void loop_unprepare_queue(struct loop_device *lo) -- 2.20.1