From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mout.gmx.net ([212.227.17.20]:49781 "EHLO mout.gmx.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750867AbcLDTVB (ORCPT ); Sun, 4 Dec 2016 14:21:01 -0500 Received: from thetick.localnet ([93.181.44.247]) by mail.gmx.com (mrgmx103 [212.227.17.168]) with ESMTPSA (Nemesis) id 0MYOCL-1c9PMu2cOP-00VBH4 for ; Sun, 04 Dec 2016 20:20:57 +0100 From: Marc Joliet To: linux-btrfs@vger.kernel.org Subject: Re: system hangs due to qgroups Date: Sun, 04 Dec 2016 20:20:51 +0100 Message-ID: <5831203.ygVuIMpfzH@thetick> In-Reply-To: References: <1776088.42rHLKPlSp@thetick> <3405186.JXS0fWUK5s@thetick> MIME-Version: 1.0 Content-Type: multipart/signed; boundary="nextPart2626642.ofJKjVAHtj"; micalg="pgp-sha256"; protocol="application/pgp-signature" Sender: linux-btrfs-owner@vger.kernel.org List-ID: --nextPart2626642.ofJKjVAHtj Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset="utf-8" On Sunday 04 December 2016 18:24:08 Duncan wrote: > Marc Joliet posted on Sun, 04 Dec 2016 17:02:48 +0100 as excerpted: > > That's a good idea, although I'll probably start with sysrescuecd (= Linux > > 4.8.5 and btrfs-progs 4.7.3), as I already have experience with it.= > >=20 > > [After trying it] > >=20 > > Well, crap, I was able to get images of the file system (one saniti= zed), > > but mounting always fails with "device or resource busy" (with no > > corresponding dmesg output). (Also, that drive's partitions weren'= t > > discovered on bootup, I had to run partprobe first.) I never see t= hat > > in the initramfs, so I'm not sure what's causing that. >=20 > If I understand correctly what you're doing, that part is easily enou= gh > explained. >=20 > Remember that btrfs, unlike most filesystems, is multi-device capable= . > The way it tracks which devices belong to which filesystems is by UUI= D, > universally *UNIQUE* ID. If you image a device via dd or similar, yo= u of > course image its UUID as well, destroying the "unique" assumption in = UUID > and confusing btrfs, which will consider it part of the existing > filesystem if the original devices with that filesystem UUID remain > hooked up. >=20 > So if you did what I believe you did, try to mount the image while th= e > original filesystem devices remain attached and mounted, btrfs is sim= ply > saying that filesystem (which btrfs identifies by UUID) is already > mounted: "device or resource busy". [...] Nope, sorry if I wasn't clear, I didn't mean that I tried to mount the = image=20 (can you even mount images created with btrfs-image?). Plus the images= are=20 xz-compressed. =2D-=20 Marc Joliet =2D- "People who think they know everything really annoy those of us who kno= w we don't" - Bjarne Stroustrup --nextPart2626642.ofJKjVAHtj Content-Type: application/pgp-signature; name="signature.asc" Content-Description: This is a digitally signed message part. Content-Transfer-Encoding: 7Bit -----BEGIN PGP SIGNATURE----- iQIcBAABCAAGBQJYRGyTAAoJEL/Q5oYsiHj0FxsP/jQ8RHbdD2ytznY4gleOtLcF B+AIA+SmtDjJQ6HDxeMFJBaaJEgtyJx3r1vtxxcS0u5EcNM4TukqU5sgHjssmG9X P3vT6mJsyV/QWkaV48UC14UTDW0mvMN5Mi6aZjAGyRXXymVmyO8yhqfGD9oWnEJY wEmy1Mb/JbqFHtjKnnDMZF+MjF2Jh9HVm940G+gTsyY1oESnw0R0NcKyhIJ5NVFl +6MgLGIoXGZc5XRRbFLTt4bLRGDmADMHZfNM/9hHJ/zlk+CKF79RWCCkgdvw148v ygClvW4nJn5dkFpFTZcKeDXEqvWdjM7fREDxrrw+5kTowXOzkmQJty7iwCZULome lY515ANJw4S2St5OdSS7N3AS0Je+/uzElUY0qrauR7agW84fDFFt+MdEBYWiIR68 eBnAWYkEt6DxYeXVCQr5m17qcRwlR6i5ScNJLkSCP5JoD2OxktQk083jrerrS4/Z 1ozzNYFwD0uJsW6P5oQp6mG9xIAjtw0FR8Rm8LLBMWxi9UVTzi4qtlGH5dzxvwRk aDpYv37NksiODnmJOQrBQfg/3YeLhbLTaNtcNlhI5xx8di9j8OVZVuBkBs9yjAdi 9cHveK+/AuX7lDFB2bXo0CS5zPTEAZOkc2y38JOTMRAzBCG3oEgXWCP/GCBMw5qQ Jrip1qVO/9fVBco/C6Z3 =+NPf -----END PGP SIGNATURE----- --nextPart2626642.ofJKjVAHtj--