From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from pepin.polanet.pl ([193.34.52.2]:42138 "EHLO pepin.polanet.pl" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750975AbdLAQci (ORCPT ); Fri, 1 Dec 2017 11:32:38 -0500 Date: Fri, 1 Dec 2017 17:15:55 +0100 From: Tomasz Pala To: linux-btrfs@vger.kernel.org Subject: exclusive subvolume space missing Message-ID: <20171201161555.GA11892@polanet.pl> MIME-Version: 1.0 Content-Type: text/plain; charset=iso-8859-2 Sender: linux-btrfs-owner@vger.kernel.org List-ID: Hello, I got a problem with btrfs running out of space (not THE Internet-wide, well known issues with interpretation). The problem is: something eats the space while not running anything that justifies this. There were 18 GB free space available, suddenly it dropped to 8 GB and then to 63 MB during one night. I recovered 1 GB with rebalance -dusage=5 -musage=5 (or sth about), but it is being eaten right now, just as I'm writing this e-mail: /dev/sda2 64G 63G 452M 100% / /dev/sda2 64G 63G 365M 100% / /dev/sda2 64G 63G 316M 100% / /dev/sda2 64G 63G 287M 100% / /dev/sda2 64G 63G 268M 100% / /dev/sda2 64G 63G 239M 100% / /dev/sda2 64G 63G 230M 100% / /dev/sda2 64G 63G 182M 100% / /dev/sda2 64G 63G 163M 100% / /dev/sda2 64G 64G 153M 100% / /dev/sda2 64G 64G 143M 100% / /dev/sda2 64G 64G 96M 100% / /dev/sda2 64G 64G 88M 100% / /dev/sda2 64G 64G 57M 100% / /dev/sda2 64G 64G 25M 100% / while my rough calculations show, that there should be at least 10 GB of free space. After enabling quotas it is somehow confirmed: # btrfs qgroup sh --sort=excl / qgroupid rfer excl -------- ---- ---- 0/5 16.00KiB 16.00KiB [30 snapshots with about 100 MiB excl] 0/333 24.53GiB 305.79MiB 0/298 13.44GiB 312.74MiB 0/327 23.79GiB 427.13MiB 0/331 23.93GiB 930.51MiB 0/260 12.25GiB 3.22GiB 0/312 19.70GiB 4.56GiB 0/388 28.75GiB 7.15GiB 0/291 30.60GiB 9.01GiB <- this is the running one This is about 30 GB total excl (didn't find a switch to sum this up). I know I can't just add 'excl' to get usage, so tried to pinpoint the exact files that occupy space in 0/388 exclusively (this is the last snapshots taken, all of the snapshots are created from the running fs). Now, the weird part for me is exclusive data count: # btrfs sub sh ./snapshot-171125 [...] Subvolume ID: 388 # btrfs fi du -s ./snapshot-171125 Total Exclusive Set shared Filename 21.50GiB 63.35MiB 20.77GiB snapshot-171125 How is that possible? This doesn't even remotely relate to 7.15 GiB from qgroup.~The same amount differs in total: 28.75-21.50=7.25 GiB. And the same happens with other snapshots, much more exclusive data shown in qgroup than actually found in files. So if not files, where is that space wasted? Metadata? btrfs-progs-4.12 running on Linux 4.9.46. best regards, -- Tomasz Pala