From mboxrd@z Thu Jan 1 00:00:00 1970 From: Josef Bacik Subject: Re: [PATCH 1/1] btrfs: btrfs_calc_avail_data_space cope with no read/write devices V2 Date: Mon, 01 Aug 2011 11:24:32 -0400 Message-ID: <4E36C530.5030003@redhat.com> References: <1312205910-13053-1-git-send-email-apw@canonical.com> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1 Cc: Chris Mason , linux-btrfs@vger.kernel.org, linux-kernel@vger.kernel.org To: Andy Whitcroft Return-path: In-Reply-To: <1312205910-13053-1-git-send-email-apw@canonical.com> List-ID: On 08/01/2011 09:38 AM, Andy Whitcroft wrote: > When we mount a btrfs filesystem from read-only media there will be no > read/write devices; for example mounting an SD card with its lock enabled. > This triggers an immediate BUG during mount: > > kernel BUG at .../fs/btrfs/super.c:984! > > This is triggered by statfs when calculating the free space in the > filesytem. We bug if the number of read/write devices is 0. > > This check seems spurious as the information collected is valid regardless > of whether the devices are read-only or not. As the count is used to > size the sort array it seems more correct to switch it to the number of > open devices. > > BugLink: http://bugs.launchpad.net/bugs/816770 > Signed-off-by: Andy Whitcroft Acked-by: Josef Bacik Thanks, Josef