From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: with ECARTIS (v1.0.0; list xfs); Wed, 16 Jul 2008 00:34:17 -0700 (PDT) Received: from cuda.sgi.com ([192.48.176.15]) by oss.sgi.com (8.12.11.20060308/8.12.11/SuSE Linux 0.7) with ESMTP id m6G7YFA2010769 for ; Wed, 16 Jul 2008 00:34:15 -0700 Received: from ipmail01.adl6.internode.on.net (localhost [127.0.0.1]) by cuda.sgi.com (Spam Firewall) with ESMTP id 8570018DB3E0 for ; Wed, 16 Jul 2008 00:35:21 -0700 (PDT) Received: from ipmail01.adl6.internode.on.net (ipmail01.adl6.internode.on.net [203.16.214.146]) by cuda.sgi.com with ESMTP id VMuWqaN7ZMpuBaGo for ; Wed, 16 Jul 2008 00:35:21 -0700 (PDT) Date: Wed, 16 Jul 2008 17:35:03 +1000 From: Dave Chinner Subject: Re: Power loss causes bad magic number?? Message-ID: <20080716073503.GE29319@disturbed> References: <487D5F80.1050909@sandeen.net> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: Sender: xfs-bounce@oss.sgi.com Errors-to: xfs-bounce@oss.sgi.com List-Id: xfs To: Stephen Porter Cc: Eric Sandeen , xfs@oss.sgi.com On Wed, Jul 16, 2008 at 05:01:56PM +1000, Stephen Porter wrote: > Hi Eric, > > It's not an in-kernel driver, I need to rebuild it each time the kernel is updated. > > The output of the dd command follows: > > $ sudo dd if=/dev/sdc bs=512 count=128 iflag=direct | hexdump -C | grep XFSB > 128+0 records in > 128+0 records out > 65536 bytes (66 kB) copied, 0.0241381 s, 2.7 MB/s > > I thought the XFSB marked the start of the superblock... and it not being there would be a Bad Thing?? > > without the "| grep XFSB" the output looks like: > > $ sudo dd if=/dev/sdc bs=512 count=128 iflag=direct | hexdump -C > 00000000 33 c0 8e d0 bc 00 7c fb 50 07 50 1f fc be 1b 7c |3.....|.P.P....|| > 00000010 bf 1b 06 50 57 b9 e5 01 f3 a4 cb bd be 07 b1 04 |...PW...........| > 00000020 38 6e 00 7c 09 75 13 83 c5 10 e2 f4 cd 18 8b f5 |8n.|.u..........| > 00000030 83 c6 10 49 74 19 38 2c 74 f6 a0 b5 07 b4 07 8b |...It.8,t.......| > 00000040 f0 ac 3c 00 74 fc bb 07 00 b4 0e cd 10 eb f2 88 |..<.t...........| > 00000050 4e 10 e8 46 00 73 2a fe 46 10 80 7e 04 0b 74 0b |N..F.s*.F..~..t.| > 00000060 80 7e 04 0c 74 05 a0 b6 07 75 d2 80 46 02 06 83 |.~..t....u..F...| > 00000070 46 08 06 83 56 0a 00 e8 21 00 73 05 a0 b6 07 eb |F...V...!.s.....| > 00000080 bc 81 3e fe 7d 55 aa 74 0b 80 7e 10 00 74 c8 a0 |..>.}U.t..~..t..| > 00000090 b7 07 eb a9 8b fc 1e 57 8b f5 cb bf 05 00 8a 56 |.......W.......V| > 000000a0 00 b4 08 cd 13 72 23 8a c1 24 3f 98 8a de 8a fc |.....r#..$?.....| > 000000b0 43 f7 e3 8b d1 86 d6 b1 06 d2 ee 42 f7 e2 39 56 |C..........B..9V| > 000000c0 0a 77 23 72 05 39 46 08 73 1c b8 01 02 bb 00 7c |.w#r.9F.s......|| > 000000d0 8b 4e 02 8b 56 00 cd 13 73 51 4f 74 4e 32 e4 8a |.N..V...sQOtN2..| > 000000e0 56 00 cd 13 eb e4 8a 56 00 60 bb aa 55 b4 41 cd |V......V.`..U.A.| > 000000f0 13 72 36 81 fb 55 aa 75 30 f6 c1 01 74 2b 61 60 |.r6..U.u0...t+a`| > 00000100 6a 00 6a 00 ff 76 0a ff 76 08 6a 00 68 00 7c 6a |j.j..v..v.j.h.|j| > 00000110 01 6a 10 b4 42 8b f4 cd 13 61 61 73 0e 4f 74 0b |.j..B....aas.Ot.| > 00000120 32 e4 8a 56 00 cd 13 eb d6 61 f9 c3 49 6e 76 61 |2..V.....a..Inva| > 00000130 6c 69 64 20 70 61 72 74 69 74 69 6f 6e 20 74 61 |lid partition ta| > 00000140 62 6c 65 00 45 72 72 6f 72 20 6c 6f 61 64 69 6e |ble.Error loadin| > 00000150 67 20 6f 70 65 72 61 74 69 6e 67 20 73 79 73 74 |g operating syst| > 00000160 65 6d 00 4d 69 73 73 69 6e 67 20 6f 70 65 72 61 |em.Missing opera| > 00000170 74 69 6e 67 20 73 79 73 74 65 6d 00 00 00 00 00 |ting system.....| > 00000180 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 |................| That looks like a boot loader. > * > 000001b0 00 00 00 00 00 2c 44 63 9d 08 9e 08 00 00 00 01 |.....,Dc........| > 000001c0 01 00 fd fe 3f 3c 3f 00 00 00 be f3 0e 00 00 00 |....? 000001d0 01 3d fd fe ff ff fd f3 0e 00 e5 cb 40 0e 00 00 |.=..........@...| > 000001e0 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 |................| > 000001f0 00 00 00 00 00 00 00 00 00 00 00 00 00 00 55 aa |..............U.| > 00000200 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 |................| And at 0x200 I'd expect to see an AGF header, not zeros. To me, that says that either XFS is inside a partition on the drive or someone ran a partitioning tool on /dev/sdc and overwrote the XFS filesystem headers... Cheers, Dave. -- Dave Chinner david@fromorbit.com