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=-2.3 required=3.0 tests=DKIM_SIGNED,DKIM_VALID, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS, USER_AGENT_SANE_1 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 EF999C33CB1 for ; Thu, 16 Jan 2020 04:43:43 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id BFF8820748 for ; Thu, 16 Jan 2020 04:43:43 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=kernel-dk.20150623.gappssmtp.com header.i=@kernel-dk.20150623.gappssmtp.com header.b="WJBVY3nC" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726552AbgAPEnn (ORCPT ); Wed, 15 Jan 2020 23:43:43 -0500 Received: from mail-pj1-f66.google.com ([209.85.216.66]:53677 "EHLO mail-pj1-f66.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1729138AbgAPEnn (ORCPT ); Wed, 15 Jan 2020 23:43:43 -0500 Received: by mail-pj1-f66.google.com with SMTP id n96so937745pjc.3 for ; Wed, 15 Jan 2020 20:43:42 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel-dk.20150623.gappssmtp.com; s=20150623; h=subject:to:cc:references:from:message-id:date:user-agent :mime-version:in-reply-to:content-language:content-transfer-encoding; bh=tQOS9ykL8kDiDpFhWlW2cOv2Kzb1Z6JcIaDHRAWaufU=; b=WJBVY3nCN+GyBuVTM1QYsofvrmOXGph08lGYpnvCuF2D+M88uj4+OP5MKiGtBRHxg9 HnvnMWYkPTmEv9Zv0ZDGmoM/SYHgPKaXX+gCDOAZGgUpJN2hl+IWVg4XBB/6WIj/Ey+s blEroMTCohOFOgfzEKNsF/JU6KuO5uuCZqCuwk9TM52gMHxbliPeAp2cKms8qDud3P8t 05kd2GQJDrS7+u2Tv2MLusQ66jq7O93NiB+DgkRZViSZ8Et5GFVYGJSvJ7eG6hr4pLjb ji+fzx59BogME+3RZ3TV7uk2BdDJ1jpUqdVIhJ8dauAG9RyONSzQoU9idTKuKH7sdeJA ntGA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:subject:to:cc:references:from:message-id:date :user-agent:mime-version:in-reply-to:content-language :content-transfer-encoding; bh=tQOS9ykL8kDiDpFhWlW2cOv2Kzb1Z6JcIaDHRAWaufU=; b=UUhk0O8KlIwfaF0LoddMykT524K7iSmk/FhLNUNCLtCHXSCKmoSkaeFmeHxcMeORGD +2Rsg29PIObojywwymkoEDSXsVLI6sJRKzfRP2c+LQHx8Otb19Xoui8uwxdq+/LO27oL G3yPQxShz2fiMftauTaCC0ASU64uBm9zJ4/8icuSiI+C4FfJgmVKxidHVlGABJnAyd4M ciMCxF6NmhAwV32UIEh/esAOOJPW93/Mf/QYCuW9n3nPbQryFW/tkpuvi/v2Mb7NXby6 uUaouapj18Y9NouffUpHFYV7Mj1zsuldoRGmo/FsqFA9Jp29tWkPlS9X+u0Sal+X4o6n XX8Q== X-Gm-Message-State: APjAAAWWjdFMiWkOxy5LaUcjzBJSgHdgzib1FRfNSP2WsHQtsKx28bd1 dmsuNxIk+IiXNWpU3bf2mm4cghGdiNM= X-Google-Smtp-Source: APXvYqzOne459gI8+ok09JE1JN36m1QzqwT/j4wr0q9YgDvHpfW1mqNP0LmmW1pvFG8+z+uaV60IZg== X-Received: by 2002:a17:902:8f8e:: with SMTP id z14mr22136266plo.195.1579149822350; Wed, 15 Jan 2020 20:43:42 -0800 (PST) Received: from [192.168.1.188] ([66.219.217.145]) by smtp.gmail.com with ESMTPSA id z30sm22451520pff.131.2020.01.15.20.43.41 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Wed, 15 Jan 2020 20:43:41 -0800 (PST) Subject: Re: [PATCH] block: fix an integer overflow in logical block size To: Mikulas Patocka Cc: dm-devel@redhat.com, linux-block@vger.kernel.org, Mike Snitzer References: From: Jens Axboe Message-ID: Date: Wed, 15 Jan 2020 21:43:40 -0700 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:68.0) Gecko/20100101 Thunderbird/68.2.2 MIME-Version: 1.0 In-Reply-To: Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 7bit Sender: linux-block-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-block@vger.kernel.org On 1/15/20 6:35 AM, Mikulas Patocka wrote: > Logical block size has type unsigned short. That means that it can be at > most 32768. However, there are architectures that can run with 64k pages > (for example arm64) and on these architectures, it may be possible to > create block devices with 64k block size. > > For exmaple (run this on an architecture with 64k pages): > # modprobe brd rd_size=1048576 > # dmsetup create cache --table "0 `blockdev --getsize /dev/ram0` writecache s /dev/ram0 /dev/ram1 65536 0" > # mkfs.ext4 -b 65536 /dev/mapper/cache > # mount -t ext4 /dev/mapper/cache /mnt/test > > Mount will fail with this error because it tries to read the superblock using 2-sector > access: > device-mapper: writecache: I/O is not aligned, sector 2, size 1024, block size 65536 > EXT4-fs (dm-0): unable to read superblock > > This patch changes the logical block size from unsigned short to unsigned > int to avoid the overflow. Thanks, applied. -- Jens Axboe