From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-it0-f46.google.com ([209.85.214.46]:38272 "EHLO mail-it0-f46.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S935711AbeCBQT4 (ORCPT ); Fri, 2 Mar 2018 11:19:56 -0500 Received: by mail-it0-f46.google.com with SMTP id j7so2427205ita.3 for ; Fri, 02 Mar 2018 08:19:56 -0800 (PST) MIME-Version: 1.0 In-Reply-To: <20180302151805.GB5942@twin.jikos.cz> References: <20180302151805.GB5942@twin.jikos.cz> From: Menion Date: Fri, 2 Mar 2018 17:19:34 +0100 Message-ID: Subject: Re: dmesg flooded with "Very big device. Trying to use READ CAPACITY(16)" with 8TB HDDs To: dsterba@suse.cz, Menion , linux-btrfs@vger.kernel.org Content-Type: text/plain; charset="UTF-8" Sender: linux-btrfs-owner@vger.kernel.org List-ID: Thanks My point was to understand if this action was taken by BTRFS or automously by scsi. >>From your word it seems clear to me that this should go in KERNEL_DEBUG level, instead of KERNEL_NOTICE Bye 2018-03-02 16:18 GMT+01:00 David Sterba : > On Fri, Mar 02, 2018 at 12:37:49PM +0100, Menion wrote: >> Is it really a no problem? I mean, for some reason BTRFS is >> continuously read the HDD capacity in an array, that does not seem to >> be really correct > > The message comes from SCSI: > https://elixir.bootlin.com/linux/latest/source/drivers/scsi/sd.c#L2508 > > Reading drive capacity could be totally opaque for the filesystem, eg. > when the scsi layer compares the requested block address with the device > size. > > The sizes of blockdevices is obtained from the i_size member of the > inode representing the block device, so there's no direct read by btrfs. > You'd have better luck reporting that to scsi or block layer > mailinglists.