From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mout.gmx.net ([212.227.15.15]:59283 "EHLO mout.gmx.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1731734AbeG2BMc (ORCPT ); Sat, 28 Jul 2018 21:12:32 -0400 Subject: Re: btrfs-convert missing in btrfs-tools v4.15.1 To: Nicholas D Steeves , jkexcel Cc: linux-btrfs@vger.kernel.org References: <1438689914.6655.1532811050018@connect.xfinity.com> <20180728213448.GA16016@DigitalMercury.dynalias.net> From: Qu Wenruo Message-ID: <6c37e7ef-5669-7464-c72a-69a2074ebfb1@gmx.com> Date: Sun, 29 Jul 2018 07:44:05 +0800 MIME-Version: 1.0 In-Reply-To: <20180728213448.GA16016@DigitalMercury.dynalias.net> Content-Type: multipart/signed; micalg=pgp-sha256; protocol="application/pgp-signature"; boundary="1nM0niQEXS38HPmQD4lx8IaQRIE5oTwyH" Sender: linux-btrfs-owner@vger.kernel.org List-ID: This is an OpenPGP/MIME signed message (RFC 4880 and 3156) --1nM0niQEXS38HPmQD4lx8IaQRIE5oTwyH Content-Type: multipart/mixed; boundary="yBdBXgQG2w6Fb3HIvMJ3MV92AhyGcKH9K"; protected-headers="v1" From: Qu Wenruo To: Nicholas D Steeves , jkexcel Cc: linux-btrfs@vger.kernel.org Message-ID: <6c37e7ef-5669-7464-c72a-69a2074ebfb1@gmx.com> Subject: Re: btrfs-convert missing in btrfs-tools v4.15.1 References: <1438689914.6655.1532811050018@connect.xfinity.com> <20180728213448.GA16016@DigitalMercury.dynalias.net> In-Reply-To: <20180728213448.GA16016@DigitalMercury.dynalias.net> --yBdBXgQG2w6Fb3HIvMJ3MV92AhyGcKH9K Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: quoted-printable On 2018=E5=B9=B407=E6=9C=8829=E6=97=A5 05:34, Nicholas D Steeves wrote: > Resending because I forgot to CC list. >=20 > Hi jkexcel, >=20 > On 28 July 2018 at 16:50, jkexcel wrote: >> >> I'm an end user trying to use btrfs-convert but when I installed >> btrfs-tools and its dependency btrfs-progs on kubuntu 18.04, the >> installation was successful, and it shows that v4.15.1-1build1 was >> installed. >> >> However, when using the command # brtfs-convert /dev/sda4 (with the >> drive unmounted) the resulting error appears "command not found" >> I also tried command "btrfs convert" in case this was folded into the >> main tool, but this also failed. >> >> 1. Is btrfs-convert still available? >> >> 2. Where can I find it? >> >> 3. Has btrfs-convert been replaced? what is it's new name? >> >> 4. Is it safe to use a downgraded version of btrfs-tools ie: 4.14 or >> older? >=20 > You can blame me for that. In Debian several users had reported > release-critical issues in btrfs-convert, so I submitted a patch to > disable it for the forseable future, eg: >=20 > https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=3D864798 > https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=3D854489 Both report looks pretty old (4.7~4.9). In fact, just in v4.10 we had a big rework for convert. It should work much better after that. Furthermore, we have newer (but smaller) fixes to remove a lot of BUG_ON(), and do graceful exit for ENOSPC case since then. And the design of btrfs-convert (at least for the latest btrfs-convert) is to ensure until everything goes well, we won't touch any bytes of the ext* fs (in fact we open the ext* fs in RO mode). So it at least won't corrupt the ext* fs. >=20 > Also, please consider the official status "As of 4.0 kernels this featu= re > is not often used or well tested anymore, and there have been some repo= rts > that the conversion doesn't work reliably. Feel free to try it out, but= > make sure you have backups" ( > https://btrfs.wiki.kernel.org/index.php/Conversion_from_Ext3 ). The wiki page looks needs to be updated. Both btrfs-convert and base btrfs-progs are improving, especially after v4.10 btrfs-convert goes through a big rework and works well so far, and even added support for reiserfs under the same framwork. So IMHO it's at least worth trying. Thanks, Qu >=20 > I'm happy to hear it is still disabled in Ubuntu, where many more > users would be affected. IIRC OpenSUSE LEAP and SLED 15 reenabled it > (it was previously disabled there), so maybe it needs specific kernel > versions or patches to not trigger RC bugs, and/or very specific > btrfs-progs versions, and/or very specific e2fslibs, and/or specific > combinations? While I very much look forward to the day when > btrfs-convert can be relied on in Debian, I don't think we're there > yet. Please take this as an opportunity to test that your backups are > restorable, mkfs.btrfs, and then restore from backup. P.S. I have no > idea if Ubuntu has additional btrfs support. >=20 > Cheers, > Nicholas >=20 --yBdBXgQG2w6Fb3HIvMJ3MV92AhyGcKH9K-- --1nM0niQEXS38HPmQD4lx8IaQRIE5oTwyH Content-Type: application/pgp-signature; name="signature.asc" Content-Description: OpenPGP digital signature Content-Disposition: attachment; filename="signature.asc" -----BEGIN PGP SIGNATURE----- iQEzBAEBCAAdFiEELd9y5aWlW6idqkLhwj2R86El/qgFAltc/8YACgkQwj2R86El /qgsRQf+NZc8/iQguMEsCeECM8zE+uVkIACIwshDammVeuWv0IfaYqzHuS7cbpnE W/0TKYUQ5xdUPhk1fRKBNF8/okFXvzdQFVFDUNaDaQzbYNFiTSbmTsmJT9Hjc/KP d/NK0AweZn3UlaHWjlQ2970whFMoCFDuME6LAk0tGtathxLT6vKmNr+FqeK5oezq bqQpnC9qIFfBbe5tcfOKJJ3kBDtaPk/wDon/mWl8u9QC5/kplfbH0d5mRgLxczVD zMgZjnLHBVsLKt4VictGS7JTgogR6t9lYXgN0wV5jq1LG6Qro816qUimtvBuyXYe V7xK2W9i9EZMmj1fcwZjF35cB8oAKA== =jsYH -----END PGP SIGNATURE----- --1nM0niQEXS38HPmQD4lx8IaQRIE5oTwyH--