From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from pepin.polanet.pl ([193.34.52.2]:54370 "EHLO pepin.polanet.pl" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751792AbdLJPiG (ORCPT ); Sun, 10 Dec 2017 10:38:06 -0500 Date: Sun, 10 Dec 2017 16:38:05 +0100 From: Tomasz Pala To: constantine Cc: Btrfs BTRFS Subject: Re: ERROR: failed to repair root items: Input/output error Message-ID: <20171210153804.GA32313@polanet.pl> References: MIME-Version: 1.0 Content-Type: text/plain; charset=iso-8859-2 In-Reply-To: Sender: linux-btrfs-owner@vger.kernel.org List-ID: On Sun, Dec 10, 2017 at 15:18:32 +0000, constantine wrote: > I have a laptop root hard drive (Samsung SSD 850 EVO 1TB), which is > within warranty. > I can't mount it read-write ("no rw mounting after error"). There is a data-corruption issue with this controller! The same as 840 EVO - just google this. In short: either use recent kernel (AFAIR 4.0.5+ for 840 EVO and some newer for entire 8* Samsung SSD family blacklisting) or disable NCQ. Using queued TRIM on this drive leads to data loss! Firmware zeroes fist 512 bytes of a block, sorry. If you only had smaller drive, as 850s up to 512 GB have different controller... > checksum verify failed on 103009173504 found 25334496 wanted 00003500 > bytenr mismatch, want=103009173504, have=889192478 > ERROR: failed to repair root items: Input/output error > > What do these errors mean? > What should I do to fix the filesystem and be able to mount it read-write? You probably can't fix this - there is data missing on bare metal, so you should recover using backups. If you don't have one, you need to perform manual data recovery procedures (like photorec) with little chances to restore complete files due to the nature of data loss (beginning of blocks). -- Tomasz Pala