From mboxrd@z Thu Jan 1 00:00:00 1970 From: Goffredo Baroncelli Subject: Re: Grow btrfs partition & filesystem backwards Date: Wed, 09 Nov 2011 19:58:44 +0100 Message-ID: <2286851.zJGgl5jPAW@venice> References: <20111109133624.GO4149@shiny> Reply-To: Goffredo Baroncelli Mime-Version: 1.0 Content-Type: text/plain; charset=iso-8859-1 Cc: Ernst =?ISO-8859-1?Q?Sj=F6strand?= , Jordan Windsor , linux-btrfs@vger.kernel.org To: Chris Mason , Billy Crook , chris.mason@oracle.com Return-path: In-Reply-To: <20111109133624.GO4149@shiny> List-ID: On Wednesday, 09 November, 2011 08:36:24 Chris Mason wrote: > The only choice for an online operation is to make a new partition in > front of the old one and just add that as a second disk in btrfs. >=20 > The slow method of shifting the bytes down is probably a better long > term choice. >=20 > -chris Hi Chris, does the chunk tree be able to map the sectors "before" ? If so we shou= ld only=20 "shift down" the map logical->physical in the chunk tree/device tree. The only exception should be the superblock which has to be moved. At the mount time we should pass a parameter which set how the data sho= uld be=20 moved backward. Then the kernel remap the chunk tree/device tree. I don't know if the gains is greater than the work, but from a theoreti= cal=20 point of view, it should be doable.. >=20 > On Wed, Nov 09, 2011 at 06:40:06AM -0600, Billy Crook wrote: > > I think the biggest point of contention is that with all the stuff > > going on in the background in btrfs, its difficult to be sure that = the > > resize operation has completed. With grows, you don't have to worr= y. > > With shrinks, if you truncate the block device too soon, you will > > corrupt the filesystem. > >=20 > > 2011/11/9 Ernst Sj=F6strand : > > > Gparted can do that, it just takes a very long time because it mo= ves > > > everything back first. > > >=20 > > > Regards > > > //Ernst > > >=20 > > > On Wed, Nov 9, 2011 at 05:23, Jordan Windsor = wrote: > > >> Hello, > > >> I was wondering how I would go about growing a btrfs filesystem > > >> backwards, I don't have any space to store the files temporally, > > >> I'd > > >> need to do it in place. > > >> Thanks. > > >> -- > > >> To unsubscribe from this list: send the line "unsubscribe > > >> linux-btrfs" in the body of a message to > > >> majordomo@vger.kernel.org > > >> More majordomo info at http://vger.kernel.org/majordomo-info.ht= ml > > >=20 > > > -- > > > To unsubscribe from this list: send the line "unsubscribe > > > linux-btrfs" in the body of a message to majordomo@vger.kernel.or= g > > > More majordomo info at http://vger.kernel.org/majordomo-info.htm= l > >=20 > > -- > > To unsubscribe from this list: send the line "unsubscribe linux-btr= fs" > > in > > the body of a message to majordomo@vger.kernel.org > > More majordomo info at http://vger.kernel.org/majordomo-info.html >=20 > -- > To unsubscribe from this list: send the line "unsubscribe linux-btrfs= " in > the body of a message to majordomo@vger.kernel.org > More majordomo info at http://vger.kernel.org/majordomo-info.html --=20 gpg key@ keyserver.linux.it: Goffredo Baroncelli (ghigo) Key fingerprint =3D 4769 7E51 5293 D36C 814E C054 BF04 F161 3DC5 0512 -- To unsubscribe from this list: send the line "unsubscribe linux-btrfs" = in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html