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,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH, MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED, USER_AGENT_GIT autolearn=ham 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 BF563C432C3 for ; Thu, 14 Nov 2019 23:50:40 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 8FF5720725 for ; Thu, 14 Nov 2019 23:50:40 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=chromium.org header.i=@chromium.org header.b="L9a4l7NP" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727226AbfKNXuj (ORCPT ); Thu, 14 Nov 2019 18:50:39 -0500 Received: from mail-pg1-f196.google.com ([209.85.215.196]:43197 "EHLO mail-pg1-f196.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726767AbfKNXuj (ORCPT ); Thu, 14 Nov 2019 18:50:39 -0500 Received: by mail-pg1-f196.google.com with SMTP id l24so4777117pgh.10 for ; Thu, 14 Nov 2019 15:50:38 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=chromium.org; s=google; h=from:to:cc:subject:date:message-id:in-reply-to:references :mime-version:content-transfer-encoding; bh=3xLmV31uV8sM4q8H6KSowg3F9gbdl9L8XRHqhlyar5o=; b=L9a4l7NPquiUXQMobq4Dez8ZdS8/Czp02wJHySZBb3K6sNPls2tY42E7ruHtIfh2xr L8nurcUTaVZ8dRdBgXD3BJXmN253Z1asF35HHGVjECqF04SsSUF1X2QdKYYs1/PUXbxJ erq4OSjRdw9Z2+8Z+d46CvuzDPxhEt4f68nvY= X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:from:to:cc:subject:date:message-id:in-reply-to :references:mime-version:content-transfer-encoding; bh=3xLmV31uV8sM4q8H6KSowg3F9gbdl9L8XRHqhlyar5o=; b=XlgL+NK+wJ+3PV1m630cGjnLrmAaOhzYN0fJitAscADPABBCClRTyT9czOcR2rj7fj 2oGOIo/LU0QUs0zceYHxBT5Wey3Mb675nABj+LpZGTaGVPokIfM29T7NFJ88PNoATZs+ 1f3nRSl4C1wt6Ey6vw57XouKMH42VwZjQzpCASwM7XRVSiRjdtpG38AE6GkBDGGSUbkG T1JB6H1n2fURtHwI0Sb7xUHuHhuu9PpuG0qmtpPm+adX6h3UIgu1j7xFR2PhuDv7mAqV piBUU3ht3aVUkRN6JcFIRfBbaej7GoZUIswHo+Hcwv6pO54vIlg5rSA99b8XTUu1mvCa oVww== X-Gm-Message-State: APjAAAW9EOiVaJXehyiP0afsV2xsCkH8yKyrFdhiJQnmI3pi83bVsYjc O4zq6SJEf0sgos+4hBSmrwU6tQ== X-Google-Smtp-Source: APXvYqx/CkE8kDEbnpvc/CMHWAp1Q3s8BWqQN6XolX6NapCaW+yRtjLdNapPsB5aJiq/tjRdLabCKA== X-Received: by 2002:aa7:8dd0:: with SMTP id j16mr13544458pfr.58.1573775437840; Thu, 14 Nov 2019 15:50:37 -0800 (PST) Received: from evgreen2.mtv.corp.google.com ([2620:15c:202:201:ffda:7716:9afc:1301]) by smtp.gmail.com with ESMTPSA id v63sm7904458pfb.181.2019.11.14.15.50.36 (version=TLS1_2 cipher=ECDHE-RSA-AES128-SHA bits=128/128); Thu, 14 Nov 2019 15:50:37 -0800 (PST) From: Evan Green To: Jens Axboe , Martin K Petersen Cc: Gwendal Grignou , Christoph Hellwig , Ming Lei , "Darrick J . Wong" , Alexis Savery , Douglas Anderson , Bart Van Assche , Evan Green , Chaitanya Kulkarni , linux-block@vger.kernel.org, linux-kernel@vger.kernel.org Subject: [PATCH v7 2/2] loop: Better discard support for block devices Date: Thu, 14 Nov 2019 15:50:08 -0800 Message-Id: <20191114154903.v7.2.I4d476bddbf41a61422ad51502f4361e237d60ad4@changeid> X-Mailer: git-send-email 2.21.0 In-Reply-To: <20191114235008.185111-1-evgreen@chromium.org> References: <20191114235008.185111-1-evgreen@chromium.org> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 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 --- Changes in v7: - Rebase on top of Darrick's patch - Tweak opening line of commit description (Darrick) Changes in v6: None 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 commit description Changes in v2: None drivers/block/loop.c | 40 +++++++++++++++++++++++++++++----------- 1 file changed, 29 insertions(+), 11 deletions(-) diff --git a/drivers/block/loop.c b/drivers/block/loop.c index 6a9fe1f9fe84..e8f23e4b78f7 100644 --- a/drivers/block/loop.c +++ b/drivers/block/loop.c @@ -427,11 +427,12 @@ 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; } @@ -862,6 +863,21 @@ static void loop_config_discard(struct loop_device *lo) struct file *file = lo->lo_backing_file; struct inode *inode = file->f_mapping->host; struct request_queue *q = lo->lo_queue; + struct request_queue *backingq; + + /* + * If the backing device is a block device, mirror its zeroing + * capability. REQ_OP_DISCARD translates to a zero-out even when backed + * by block devices to keep consistent behavior with file-backed loop + * devices. + */ + if (S_ISBLK(inode->i_mode) && !lo->lo_encrypt_key_size) { + 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 @@ -869,22 +885,24 @@ static void loop_config_discard(struct loop_device *lo) * 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) -- 2.21.0