From mboxrd@z Thu Jan 1 00:00:00 1970 From: dima Subject: Re: How to remount btrfs without compression? Date: Wed, 9 Nov 2011 10:01:13 +0900 Message-ID: <4EB9D0D9.1000009@parallels.com> References: <4EB72C1B.1030702@parallels.com> <201111071319.14493.Martin@lichtvoll.de> <4EB87E01.1040704@parallels.com> <4EB880A0.1030304@gmail.com> <4EB88BC9.7020509@gmail.com> <4EB88D4A.5050908@parallels.com> <20111108150151.GA4954@shiny> <20111108151208.GB4954@shiny> Mime-Version: 1.0 Content-Type: text/plain; charset="UTF-8"; format=flowed To: Return-path: In-Reply-To: <20111108151208.GB4954@shiny> List-ID: On 11/09/2011 12:12 AM, Chris Mason wrote: > On Tue, Nov 08, 2011 at 10:01:51AM -0500, Chris Mason wrote: >> On Tue, Nov 08, 2011 at 11:00:42AM +0900, dima wrote: >>> On 11/08/2011 10:54 AM, Eric Griffith wrote: >>>> On 11/7/2011 8:52 PM, Fajar A. Nugraha wrote: >>>>> On Tue, Nov 8, 2011 at 8:06 AM, Eric Griffith >>>>> wrote: >>>>>> Edit your >>>>>> fstab, remove the compress flag, reboot. Tell btrfs to rebalance the >>>>>> system, >>>>>> reboot again. And I -THINK- that'll decompress all the files >>>>> >>>>> I think the original question was how to force uncompressed mode, >>>>> whether specific to a file or to a whole filesystem, without having to >>>>> reboot :) >>>>> >>>>> AFAIK there's no way to do that. >>>>> >>>> >>>> Whoops! Misunderstood the question haha. Yeah, as far as decompressing >>>> just a single file; from what I've read, thats impossible. >>> >>> >>> Eric, Fajar, >>> Thanks. Understood. >>> >>> Yes, it is possible to remove the compress flag from fstab, reboot >>> and even do not do any defragmentation/rebalancing - just re-save >>> the file and it will be saved uncompressed. This works. But only >>> with reboot... >> >> chattr -c on the file should work (followed by defrag or rewriting the >> file). I just retested and it seems to be broken right now. >> >> I'll track it down. > > Ok, I had forgotten. chattr -c clears the compression flag bug doesn't > set the no compress flag. We looks like we need to patch chattr for > this. > > -chris > Just for the record - I could find a solution thanks to the btrfs wiki being online again. In Gotchas it says mount -o nodatacow also disables compression and indeed it does. Remounting with this option and re-saving the file makes it uncompressed. However, I could not find how to remount the filesystem afterwards without nodatacow. ~dima