From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mout.gmx.net ([212.227.15.19]:49948 "EHLO mout.gmx.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1762622AbcLPXSl (ORCPT ); Fri, 16 Dec 2016 18:18:41 -0500 Received: from thetick.localnet ([93.181.44.247]) by mail.gmx.com (mrgmx001 [212.227.17.190]) with ESMTPSA (Nemesis) id 0MQ2Wx-1cER0U2LBb-005Ei8 for ; Sat, 17 Dec 2016 00:18:33 +0100 From: Marc Joliet To: linux-btrfs@vger.kernel.org Subject: btrfs-check finds file extent holes Date: Sat, 17 Dec 2016 00:18:13 +0100 Message-ID: <6935146.pedKUuRHNK@thetick> MIME-Version: 1.0 Content-Type: multipart/signed; boundary="nextPart3849436.OO6qEtAKF4"; micalg="pgp-sha256"; protocol="application/pgp-signature" Sender: linux-btrfs-owner@vger.kernel.org List-ID: --nextPart3849436.OO6qEtAKF4 Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset="utf-8" Hello, After my backup drive displayed a weird issue (programs accessing it su= ddenly=20 started zombifying, but it worked fine after a reboot), I decided to ch= eck the=20 file system. The initial results with btrfs-check's low-memory mode fo= und=20 reference count mismatches, but that seems to have been a false positiv= e,=20 since btrfs-check's normal mode does not find them. Instead, it compla= ins=20 about several file extent holes: # btrfs check /dev/sdd2 =20 Checking filesystem on /dev/sdd2 UUID: f97b3cda-15e8-418b-bb9b-235391ef2a38 checking extents checking free space cache checking fs roots root 30634 inode 95066 errors 100, file extent discount Found file extent holes: start: 413696, len: 4096 root 30635 inode 95066 errors 100, file extent discount Found file extent holes: start: 413696, len: 4096 root 30636 inode 95066 errors 100, file extent discount Found file extent holes: start: 413696, len: 4096 root 30657 inode 95066 errors 100, file extent discount Found file extent holes: start: 413696, len: 4096 root 30746 inode 95066 errors 100, file extent discount Found file extent holes: start: 413696, len: 4096 root 30747 inode 95066 errors 100, file extent discount Found file extent holes: start: 413696, len: 4096 root 30764 inode 95066 errors 100, file extent discount Found file extent holes: start: 413696, len: 4096 root 30834 inode 95066 errors 100, file extent discount Found file extent holes: start: 413696, len: 4096 root 30835 inode 95066 errors 100, file extent discount Found file extent holes: start: 413696, len: 4096 root 30915 inode 95066 errors 100, file extent discount Found file extent holes: start: 413696, len: 4096 root 30916 inode 95066 errors 100, file extent discount Found file extent holes: start: 413696, len: 4096 root 30942 inode 95066 errors 100, file extent discount Found file extent holes: start: 413696, len: 4096 root 31038 inode 95066 errors 100, file extent discount Found file extent holes: start: 413696, len: 4096 root 31053 inode 95066 errors 100, file extent discount Found file extent holes: start: 413696, len: 4096 root 31366 inode 95066 errors 100, file extent discount Found file extent holes: start: 413696, len: 4096 root 31367 inode 95066 errors 100, file extent discount Found file extent holes: start: 413696, len: 4096 root 31368 inode 95066 errors 100, file extent discount Found file extent holes: start: 413696, len: 4096 root 31385 inode 95066 errors 100, file extent discount Found file extent holes: start: 413696, len: 4096 root 31425 inode 95066 errors 100, file extent discount Found file extent holes: start: 413696, len: 4096 root 31473 inode 95066 errors 100, file extent discount Found file extent holes: start: 413696, len: 4096 root 31499 inode 95066 errors 100, file extent discount Found file extent holes: start: 413696, len: 4096 root 31554 inode 95066 errors 100, file extent discount Found file extent holes: start: 413696, len: 4096 root 31572 inode 95066 errors 100, file extent discount Found file extent holes: start: 413696, len: 4096 root 31606 inode 95066 errors 100, file extent discount Found file extent holes: start: 413696, len: 4096 root 31653 inode 95066 errors 100, file extent discount Found file extent holes: start: 413696, len: 4096 root 31680 inode 95066 errors 100, file extent discount Found file extent holes: start: 413696, len: 4096 (The check is still not done, it's been running for about 24 hours now.= ) Is this something that btrfs-check can safely repair, or that is perhap= s even=20 harmless? % uname -a Linux thetick 4.8.14-gentoo #1 SMP PREEMPT Sun Dec 11 17:09:09 CET 2016= x86_64=20 AMD Athlon(tm) 64 X2 Dual Core Processor 4200+ AuthenticAMD GNU/Linux % /sbin/btrfs --version btrfs-progs v4.8.5 I can't show any other output because btrfs-check is still running. I = can=20 only say that the file system is 1TB large and about 88% full (fuller t= han=20 normal, which is about 85%). Greetings =2D-=20 Marc Joliet =2D- "People who think they know everything really annoy those of us who kno= w we don't" - Bjarne Stroustrup --nextPart3849436.OO6qEtAKF4 Content-Type: application/pgp-signature; name="signature.asc" Content-Description: This is a digitally signed message part. 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