Partitions: Amiga RDB partition on 2 TB disk way too big, while OK in AmigaOS 4.1

[Martin Steigerwald <Martin@lichtvoll.de>]

Hi Jens, hi Linux m68k developers,

I reported that as

https://bugzilla.kernel.org/show_bug.cgi?id=43511

I will attach there some more debug data like binary copy of RDB and such.

But maybe its easier to discuss here.

I am not sure whether its an issue with Linux or an issue with the RDB 
format and disks with big sizes. But AFAIK RDB format is capable of 
handling 2 TB disks.




With my 2 TB mixed Amiga/Linux backup disk, which I partioned under 
AmigaOS 4.0/1 with Media Toolbox I get the following in Linux:


Jun 17 07:28:14 merkaba kernel: [30852.968978] sata_sil24 0000:05:00.0: 
enabling device (0000 -> 0003)
Jun 17 07:28:14 merkaba kernel: [30852.969401] scsi9 : sata_sil24
Jun 17 07:28:14 merkaba kernel: [30852.969533] ata10: SATA max UDMA/100 
host m128@0xf1c02000 port 0xf1c00000 irq 19
Jun 17 07:28:16 merkaba kernel: [30855.163712] ata10: SATA link up 3.0 
Gbps (SStatus 123 SControl 0)
Jun 17 07:28:16 merkaba kernel: [30855.165014] ata10.00: ATA-8: Hitachi 
HDS5C3020ALA632, ML6OA580, max UDMA/133
Jun 17 07:28:16 merkaba kernel: [30855.165017] ata10.00: 3907029168 
sectors, multi 16: LBA48 NCQ (depth 31/32)
Jun 17 07:28:16 merkaba kernel: [30855.166378] ata10.00: configured for 
UDMA/100
Jun 17 07:28:16 merkaba kernel: [30855.166477] scsi 9:0:0:0: Direct-Access     
ATA      Hitachi HDS5C302 ML6O PQ: 0 ANSI: 5
Jun 17 07:28:16 merkaba kernel: [30855.166653] sd 9:0:0:0: [sdb] 
3907029168 512-byte logical blocks: (2.00 TB/1.81 TiB)
Jun 17 07:28:16 merkaba kernel: [30855.166699] sd 9:0:0:0: [sdb] Write 
Protect is off
Jun 17 07:28:16 merkaba kernel: [30855.166702] sd 9:0:0:0: [sdb] Mode 
Sense: 00 3a 00 00
Jun 17 07:28:16 merkaba kernel: [30855.166726] sd 9:0:0:0: [sdb] Write 
cache: enabled, read cache: enabled, doesn't support DPO or FUA
Jun 17 07:28:16 merkaba kernel: [30855.200936]  sdb: RDSK (512) sdb1 
(LNX^@)(res 2 spb 1) sdb2 (JXF^D)(res 2 spb 1) sdb3 (DOS^C)(res 2 spb 4)
Jun 17 07:28:16 merkaba kernel: [30855.200943] sdb: p1 size 
18446744072560312368 extends beyond EOD, enabling native capacity
Jun 17 07:28:16 merkaba kernel: [30855.201344]  sdb: RDSK (512) sdb1 
(LNX^@)(res 2 spb 1) sdb2 (JXF^D)(res 2 spb 1) sdb3 (DOS^C)(res 2 spb 4)
Jun 17 07:28:16 merkaba kernel: [30855.201347] sdb: p1 size 
18446744072560312368 extends beyond EOD, truncated
Jun 17 07:28:16 merkaba kernel: [30855.201398] sdb: p2 start 
18446744072560314432 is beyond EOD, truncated
Jun 17 07:28:16 merkaba kernel: [30855.201400] sdb: p3 start 
18446744073189460080 is beyond EOD, truncated
Jun 17 07:28:16 merkaba kernel: [30855.201570] sd 9:0:0:0: [sdb] Attached 
SCSI disk


The first partition seems to be way to big:

merkaba:~#1> amiga-fdisk -l /dev/sdc
Disk /dev/sdc: 3 heads, 16 sectors, 81396441 cylinders, RDB: 0
Logical Cylinders from 43 to 81396440, 24576  bytes/Cylinder 

Device     Boot Mount   Begin      End     Size   Pri  BBlks    System
/dev/sdc1       *        43   65536043   1572864024     0      0  Linux 
native
/dev/sdc2       *    65536044   78643244   314572824     0      0  
[unknown]
/dev/sdc3       *    78643245   81396440   66076704     0      0  Amiga 
FFS Int.

(sdc2 is JXFS, a new filesystem in AmigaOS 4 that is not known to Linux 
yet)


In cat /proc/partitions I get:

merkaba:~> cat /proc/partitions 
major minor  #blocks  name

 […]
   8       16 1953514584 sdb
   8       17 1953513552 sdb1
merkaba:~> 


Thus the Debian Linux Kernel 3.4.1 I am using here, truncates the first 
oversized partition and has no space for the other, too, which therefore 
are inaccessible under Linux.

I didn´t notice this initially, but it happened from the beginning, I have 
an old amiga-fdisk listing that is exactly the same.

Amiga Mediatoolbox has a different oppinion on the partition layout:

LVM aka sdc1: 1500 GByte, 43 to 65536043 cyl, size 65536001 Zylinder
BAK aka sdc2: 300 GByte, 65536044 to 78643244 cyl, size 13107201 Zylinder
TAUSCH2 aka sdc3: 63,016 GByte, 78643245 to  81396440 cyl, didn´t note the 
size here, but as far as I remember was okay as well

But it seems to be confused about the whole size of the disk as well:

Logical sizes:

Blocks per cylinder: 48
Cylinders: 81396441
Sectors: -397938128
Blocksize: 512

The sectors seem overflowed.

So it might be a problem with RDB and 2TB disks and nothing to do with 
Linux. But still on AmigaOS 4.1 I can access the two Amiga partitions 
after the Linux partition.



I have another 500GB disk for backup up my Sam440ep AmigaOS 4.1 "Amiga", I 
plan to repartition the 2 TB disk as GPT anyway, but since MediaToolBox in 
AmigaOS 4.1 has a different meaning about the partioning and this can cause 
serious data loss, I think its good to look at it.

I had a BTRFS filesystem that had some checksum errors. Maybe thats somehow 
related to this issue and AmigaOS and/or Linux overwrote something it 
shouldn´t have touched.

I will report a bug with AmigaOS 4.1 developers as well to get more 
details.


merkaba:~> cat /proc/version
Linux version 3.4-trunk-amd64 (Debian 3.4.1-1~experimental.1)
(debian-kernel@lists.debian.org) (gcc version 4.6.3 (Debian 4.6.3-1) ) #1 
SMP
Wed Jun 6 10:34:53 CEST 2012

Ciao,
-- 
Martin 'Helios' Steigerwald - http://www.Lichtvoll.de
GPG: 03B0 0D6C 0040 0710 4AFA  B82F 991B EAAC A599 84C7