From mboxrd@z Thu Jan 1 00:00:00 1970 From: Roman Mamedov Subject: NOCOW + compress-force = bug Date: Thu, 16 Feb 2012 19:55:15 +0600 Message-ID: <20120216195515.643f4aa7@natsu> References: <4F38B8F0.5020506@yahoo.com> <4F38BE53.4080204@parallels.com> <20120213141040.GG15350@twin.jikos.cz> Mime-Version: 1.0 Content-Type: multipart/signed; micalg=PGP-SHA1; boundary="Sig_/veAUPMTq837EXvEkhPaP=Cd"; protocol="application/pgp-signature" Cc: dima , linux-btrfs@vger.kernel.org To: dave@jikos.cz Return-path: In-Reply-To: <20120213141040.GG15350@twin.jikos.cz> List-ID: --Sig_/veAUPMTq837EXvEkhPaP=Cd Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: quoted-printable Hello, Please be aware that there seems to be a possible problem with using NOCOW flag on files situated on a filesystem mounted with compress-force(=3Dlzo, = in my case). Since experimenting with NOCOW, I started regularly hitting this BUG at extent-tree.c:5813=20 5813 BUG_ON(!(flags & BTRFS_BLOCK_FLAG_FULL_BACKREF)); I was unable to make netconsole work over a bridged interface, so can only post screenshots of this OOPS: http://romanrm.ru/pics/2012/2012-02-16-btrfs-bug-1.jpg http://romanrm.ru/pics/2012/2012-02-16-btrfs-bug-2.jpg This happened four times already, and always on snapshot creation (but not every case). I have hourly snapshots in crontab, and only one case out of a= bout ten fails with this problem. Did not try to deliberately reproduce it yet by manually making snapshots very often, etc. On Mon, 13 Feb 2012 15:10:40 +0100 David Sterba wrote: > Hi, >=20 > On Mon, Feb 13, 2012 at 04:40:03PM +0900, dima wrote: > > Actually it is possible. Check out David's response to my question from= =20 > > some time ago: > > http://permalink.gmane.org/gmane.comp.file-systems.btrfs/14227 >=20 > this was a quick aid, please see attached file for an updated tool to set > the file flags, now added 'z' for NOCOMPRESS flag, and supports chattr > syntax plus all of the standard file flags. >=20 > Setting and unsetting nocow is done like 'fileflags +C file' or -C for > unseting. Without any + or - options it prints current state. >=20 >=20 > david --=20 With respect, Roman ~~~~~~~~~~~~~~~~~~~~~~~~~~~ "Stallman had a printer, with code he could not see. So he began to tinker, and set the software free." --Sig_/veAUPMTq837EXvEkhPaP=Cd Content-Type: application/pgp-signature; name=signature.asc Content-Disposition: attachment; filename=signature.asc -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.4.11 (GNU/Linux) iEYEARECAAYFAk89CsMACgkQTLKSvz+PZwhfIwCfZj1Db0//kskrJVYWemXrPa1z v2MAn25DFtjzFosf60LrMeoSYb/2vM1v =Bbg3 -----END PGP SIGNATURE----- --Sig_/veAUPMTq837EXvEkhPaP=Cd--