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Re: grub-mkrescue hfsplus GPT partition is not mountable on Linux
From: |
Thomas Schmitt |
Subject: |
Re: grub-mkrescue hfsplus GPT partition is not mountable on Linux |
Date: |
Fri, 25 Dec 2015 11:36:24 +0100 |
Hi,
i wrote:
> > The HFS+ failure is due to APM block size 2048.
> > Linux has 512 hardcoded.
Andrei Borzenkov wrote:
> No, it has not.
Seems to fixed meanwhile, indeed.
I patched away MBR partition table and GPT. After that, the partition
/dev/sdb3 does mount. (sdb1 is the APM partition table, sbd2 and sdb4
are "Gap0" and "Gap1".)
But there is a HFS+ problem regardless of partitioning.
See below.
> Do not confuse APM and HFS+.
I shall rather not confuse APM with GPT when reading.
> If I adjust gpt3 to be of the same size
> as apple2 it is happily mounted by Linux.
I would not have expected that the oversize spoils mountability.
Thus my misreading.
Whatever, the lack of a GPT partition for HFS+ is fixed by
http://bazaar.launchpad.net/~libburnia-team/libisofs/scdbackup/revision/1297/libisofs/system_area.c
It now yields when run by grub-mkrescue (Debian Sid, "2.02~beta2-33",
grub-efi-ia32-bin, grub-efi-amd64-bin, grub-pc-bin)
GPT partition name : 3 48004600530050004c0055005300
GPT partname local : 3 HFSPLUS
GPT partition GUID : 3 54048af0155bb44aa145348d46e87e81
GPT type GUID : 3 005346480000aa11aa1100306543ecac
GPT partition flags: 3 0x1000000000000001
GPT start and size : 3 6096 24096
together with
APM partition name : 2 HFSPLUS_Hybrid
APM partition type : 2 Apple_HFS
APM start and size : 2 1524 6024
I boot a Debian Jessie VM with that image as -hdb (booted is -hda).
fdisk reports
Device Start End Sectors Size Type
/dev/sdb1 64 335 272 136K Microsoft basic data
/dev/sdb2 336 6095 5760 2.8M EFI System
/dev/sdb3 6096 30191 24096 11.8M Apple HFS/HFS+
/dev/sdb4 30192 30791 600 300K Microsoft basic data
I can do as uperuser
# mount /dev/sdb3 /mnt/hfs
without error message.
But then there is a HFS+ problem which i cannot explain yet:
# ls /mnt/hfs
ls: reading directory /mnt/hfs: Input/output error
System boot empty-file.txt mach_kernel
whereas
# mount -o loop /dev/sdb /mnt/iso
# ls /mnt/iso
System boot boot.catalog efi.img empty-file.txt mach_kernel
dmesg has:
[ 354.871503] hfsplus: Filesystem is marked locked, mounting read-only.
[ 359.020970] hfsplus: walked past end of dir
uname -a :
Linux ... 3.16.0-4-amd64 #1 SMP Debian 3.16.7-ckt11-1+deb8u4 (2015-09-19)
x86_64 GNU/Linux
It does not look like a problem with the partition.
I have no clue of HFS+ internals. It's done by Vladimir's code in
http://bazaar.launchpad.net/~libburnia-team/libisofs/scdbackup/view/head:/libisofs/hfsplus.c
http://bazaar.launchpad.net/~libburnia-team/libisofs/scdbackup/view/head:/libisofs/hfsplus.h
http://bazaar.launchpad.net/~libburnia-team/libisofs/scdbackup/view/head:/libisofs/hfsplus_case.c
http://bazaar.launchpad.net/~libburnia-team/libisofs/scdbackup/view/head:/libisofs/hfsplus_classes.c
http://bazaar.launchpad.net/~libburnia-team/libisofs/scdbackup/view/head:/libisofs/hfsplus_decompose.c
I only provided some glue code and replacements for copyrighted
tables (which are specified freely, to our luck).
If this is a real problem with the boot purpose of the ISO, then
we will have to ask Vladimir for help.
(Mountability and readability on Linux is nice-to-have. But i
assume that Vladimir is too busy to work on such an issue.)
> > > And is the very first partition really needed?
> > Vladimir wanted it.
> Not following here.
We should ask Vladimir for the exact motivation of the filler
partitions and show him an evaluation of drawbacks.
Have a nice day :)
Thomas
Re: grub-mkrescue hfsplus GPT partition is not mountable on Linux, Thomas Schmitt, 2015/12/23