Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755973Ab1BKNEU (ORCPT ); Fri, 11 Feb 2011 08:04:20 -0500 Received: from mail-bw0-f46.google.com ([209.85.214.46]:42471 "EHLO mail-bw0-f46.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754174Ab1BKNER (ORCPT ); Fri, 11 Feb 2011 08:04:17 -0500 DomainKey-Signature: a=rsa-sha1; c=nofws; d=gmail.com; s=gamma; h=date:from:to:subject:message-id:references:mime-version :content-type:content-disposition:in-reply-to:user-agent; b=qzXa+LqVBPrK3sboC2aUkCMdIGQGSGW1j0pHp+EEnfReecmEA4T0TadUnafBsIKt27 aDqmnbp4tbcF2ZxvJknDzVF6SwOPE/QrTtssLU0O7RYtxStmBgLK7NhMzO3FmrsG7Ihd m521ihA47fdQE3lVhSXXLm7WVWX83ByJBfLiU= Date: Fri, 11 Feb 2011 14:04:12 +0100 From: Felix Blanke To: Chris Samuel , Felix Blanke , kreijack@inwind.it, Hugo Mills , linux-btrfs@vger.kernel.org, Linux Kernel Subject: Re: LOOP_GET_STATUS(64) truncates pathnames to 64 chars (was Re: Bug in mkfs.btrfs?!) Message-ID: <20110211130412.GA2591@scooter> References: <20110122144513.GA2539@scooter> <20110122145222.GB2539@scooter> <20110122151124.GC29985@carfax.org.uk> <20110122155612.GA3664@scooter> <20110123181827.GF29985@carfax.org.uk> <4D3CA568.7050506@libero.it> <20110124130104.GA7354@scooter> <4D3E160F.4050006@csamuel.org> <20110210122927.GB20488@foxbat.suse.cz> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20110210122927.GB20488@foxbat.suse.cz> User-Agent: Mutt/1.5.21 (2010-09-15) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2973 Lines: 84 Hi, are you sure that patch is in the kernel? I'm using 2.6.37 and don't have those attribues in my /sys. Felix On 10. February 2011 - 13:29, Petr Uzel wrote: > Date: Thu, 10 Feb 2011 13:29:27 +0100 > From: Petr Uzel > To: Chris Samuel > Cc: Felix Blanke , kreijack@inwind.it, Hugo Mills > , linux-btrfs@vger.kernel.org, Linux Kernel > > Subject: Re: LOOP_GET_STATUS(64) truncates pathnames to 64 chars (was Re: > Bug in mkfs.btrfs?!) > Mail-Followup-To: Chris Samuel , Felix Blanke > , kreijack@inwind.it, Hugo Mills > , linux-btrfs@vger.kernel.org, Linux Kernel > > > On Tue, Jan 25, 2011 at 11:15:11AM +1100, Chris Samuel wrote: > > /* > > * CC'd to linux-kernel in case they have any feedback on this. > > * > > * Long thread, trying to work out why mkfs.btrfs failed to > > * make a filesystem on an encrypted loopback mount called > > * /dev/loop2. Cause turned out to be mkfs.btrfs calling > > * LOOP_GET_STATUS to find out if the block device was mounted > > * and getting a truncated device name back and so it later > > * fails when lstat() is called on the truncated device path. > > * > > * The long device name for the encrypted loopback mount was > > * because /dev/disk/by-id/$ID was used when Felix created it > > * to cope with devices moving around. > > */ > > > > On 25/01/11 00:01, Felix Blanke wrote: > > > > > you were talking about the LOOP_GET_STATUS function. I'm not > > > quite sure where does it came from. Is it part of the kernel? > > > Or does it come from the util-linux package? > > > > It's in the kernel, and there is both LOOP_GET_STATUS (old > > implementation) and LOOP_GET_STATUS64 (new implementation). > > > > They return structures called loop_info and loop_info64 > > respectively and both are defined in include/linux/loop.h . > > > > Sadly in both cases the lengths of paths are defined to be > > LO_NAME_SIZE which is currently 64 and hence either > > implementation will cause the problematic: > > > > lstat("/dev/disk/by-id/ata-INTEL_SSDSA2M160G2GC_CVPO939201JX160AGN-par", > > 0x7fffa30b3cf0) = -1 ENOENT (No such file or directory) > > > > I've CC'd this to the LKML in case they have any feedback on > > this apparent problem with the API. > > Since 2.6.37, you can get full path to the backing file from sys: > cat /sys/block/loopX/loop/backing_file > > See > http://linux.derkeiler.com/Mailing-Lists/Kernel/2010-07/msg10996.html > > > HTH, > > Petr > > -- > Petr Uzel > IRC: ptr_uzl @ freenode ---end quoted text--- -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/