hfs

hfs

[Scott Knight]

	Alright, so hfs isnt working. Is anyone out there working on it?
Does anyone have any ideas as to why it stopped working in the first
place? I know its not a showstopper but it would sure be nice. Ill
probally try to look over stuff, but I dont know If ill be able to fix it,
any and all help and info, or directions to discussions about the topic
would be greatly apprecaited. Thanks.

	Scott Knight


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Re: hfs

[Michel Lanners]

Hi there,

On   3 May, this message from Scott Knight echoed through cyberspace:
> 	Alright, so hfs isnt working. Is anyone out there working on it?
> Does anyone have any ideas as to why it stopped working in the first
> place? I know its not a showstopper but it would sure be nice. Ill
> probally try to look over stuff, but I dont know If ill be able to fix it,
> any and all help and info, or directions to discussions about the topic
> would be greatly apprecaited. Thanks.

I remember discussion on some mailing list about this stuff some time
ago, but when I looked recently, I didn't find anything.

Anyway, it seems the changes in the VFS code (the layer that unifies the
various filesystems towards the rest of the kernel) broke hfs. So that's
where you need to look...

Michel

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Michel Lanners                 |  " Read Philosophy.  Study Art.
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email   mlan@cpu.lu            |
http://www.cpu.lu/~mlan        |                     Learn Always. "


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Re: hfs

[Scott Knight]

Ok heres a quick question to that followup. Even if this group gets HFS+
working that doesnt mean normal HFS will be working right? I personally
dont have any drives HFS+ formatted and dont plan on making any of them
that way. So even if HFS+ works that really doesnt help people wanting to
use HFS. Thanks for all the info.

	Scott Knight

> >
> >         Alright, so hfs isnt working. Is anyone out there working on it?
>
> There is some mythical group out there working on HFS+. I guess they
> should be able to fix HFS, too. Where they are should be detectable fom
> the list archives.
>


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Re: hfs

[Martin Costabel]

Scott Knight wrote:
>
>         Alright, so hfs isnt working. Is anyone out there working on it?

There is some mythical group out there working on HFS+. I guess they
should be able to fix HFS, too. Where they are should be detectable fom
the list archives.

> Does anyone have any ideas as to why it stopped working in the first
> place?

It has been broken since the introduction of the "new" page cache code
about a year ago in early 2.3.x. The official maintainer (A Sun of
netatalk fame) seems to be still alive, but nothing in terms of fixing
the code came from him for a year. Sometimes some changes show up in the
kernel trees, so that the code at least compiles, but it is still
broken.

>        I know its not a showstopper but it would sure be nice. Ill

I think it is pretty much a showstopper for LinuxPPC. The recommended
installations all use HFS partitions ("exchange" and now even "/boot")
mounted under Linux. None of them work under 2.3.x.

> probally try to look over stuff, but I dont know If ill be able to fix it,

This would really be great.

> any and all help and info, or directions to discussions about the topic
> would be greatly apprecaited. Thanks.

--
Martin

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Re: hfs

[David A. Gatwood]

On Wed, 3 May 2000, Scott Knight wrote:

> Ok heres a quick question to that followup. Even if this group gets HFS+
> working that doesnt mean normal HFS will be working right? I personally
> dont have any drives HFS+ formatted and dont plan on making any of them
> that way. So even if HFS+ works that really doesnt help people wanting to
> use HFS. Thanks for all the info.

I'm under the impression that HFS is basically a subset of HFS+, i.e. HFS+
working should fix HFS.  I could easily be wrong, though.  Regardless,
they're probably modifying the HFS code to also support HFS+, which
probably would mean that they'd be fixing the HFS code in the process
(since the problems are more general OS-related, rather than actual
filesystem metadata-specific bugs).  But it's hard to say for sure until
somebody actually gets it working.  ;-)


David


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Re: hfs

[Dan Bethe]

> I'm under the impression that HFS is basically a subset of HFS+, i.e.
> HFS+
> working should fix HFS.  I could easily be wrong, though.

	Well I would guess that it would, but not automatically.  If you go to
an OS that only supports HFS, and you mount an HFS+ filesystem, it will
work but only one file will be available.  It's the magic file entitled
"Where have all my files gone?" or something like that.  So technically
HFS+ is a superset of HFS.  :)
	I guess there are a bunch of people speculating all day rather than
coding it, which is understandable.  Perhaps the primary maintainers of
the most prominent HFS+ and HFS code can surface and let people know
what they're doing, and what they need help on.  Or maybe they'll just
pop up one day and say "Hey we're all done!  Here ya go!"  :^)

=====
"Don't expect your own messiah; this neverworld which you desire is
only in your mind." -- http://www.dreamtheater.net/songb4.htm#IV5


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Re: hfs

[Martin Costabel]

jingai wrote:

> I haven't tried mounting HFS cds, but I can most certainly read and write
> to HFS partiitons just fine.  I don't know exactly what could be different,
> but I haven't had any troubles with it since 2.3.99x..

I confirm Scott's observations:

1. No mounting of HFS CDs. The error message (for the LinuxPPC2000 CD,
for instance) is

root[2]#mount -t hfs /dev/cdrom /mnt/cdrom/
sr.c:Bad 2K block number requested (2 1) I/O error: dev 0b:00, sector 2
hfs_fs: unable to read block 0x00000002 from dev 0b:00
hfs_fs: Unable to read superblock
sr.c:Bad 2K block number requested (0 1) I/O error: dev 0b:00, sector 0
hfs_fs: unable to read block 0x00000000 from dev 0b:00
hfs_fs: Unable to read block 0.
mount: wrong fs type, bad option, bad superblock on /dev/cdrom,
       or too many mounted file systems

Note that this sam CD mounts perfectly with a 2.2.15-pre20 kernel.

2. Hard freeze after mounting of a HFS partition. Sometimes (I did a
couple of tests with a hfs ZIP; it's a PITA to wait 10 minutes for the
reboot with fsck each time) I can copy one or two files on the HFS
partitions, but sometimes it freezes immediately, and it freezes for
sure when I cd there and compile some little C program.
With xmon enabled, the following OOPS is captured:

bad magic 0 (should be c50c7740, creator 0), wq bug, forcing oops.

Then there follow addresses, with NIP decoded as <hfs_bnode_relse+110>
(this is defined in fs/hfs/bnode.c). All other addresses are in the
C[3-5]xxxxxx range which is not in kernel space, so I cannot decode
them. "Task" is 'cd' or 'ld' or whatever I was doing when the freeze
occurred. The oops message is generated by include/linux/wait.h.

I can see that Paul applied some changes to fs/hfs/inode.c recently, but
this doesn't change anything for me. I noted (and reported) the
brokenness of hfs at least as early as 2.3.18. I am willing to help, but
my own understanding of file systems in general, hfs in particular, and
wait queues and such stuff is too limited to get me anywhere on my own.

--
Martin

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Re: hfs

[flar]

Dan Bethe wrote:
> > I'm under the impression that HFS is basically a subset of HFS+, i.e.
> > HFS+
> > working should fix HFS.  I could easily be wrong, though.
> 	Well I would guess that it would, but not automatically.  If you go to
> an OS that only supports HFS, and you mount an HFS+ filesystem, it will
> work but only one file will be available.  It's the magic file entitled
> "Where have all my files gone?" or something like that.  So technically
> HFS+ is a superset of HFS.  :)

No, HFS+ is similar to HFS, and an HFS+ filesystem can be (and usually is)
wrapped in an HFS filesystem.  All that needs to be read out of the HFS
filesystem to get to the HFS+ filesystem is about a dozen bytes of the MDB.

> 	I guess there are a bunch of people speculating all day rather than
> coding it, which is understandable.  Perhaps the primary maintainers of
> the most prominent HFS+ and HFS code can surface and let people know
> what they're doing, and what they need help on.  Or maybe they'll just
> pop up one day and say "Hey we're all done!  Here ya go!"  :^)

No, there's a bunch of people that have things they are being paid to do
that take up most of their time.  I am the lead of the HFS+ code, and I
know I haven't had time to touch it in about 5 or 6 months.  The other
people who are helping me aren't much better off.  If other people want
to help, they're welcome...

	Brad Boyer
	flar@pants.nu

P.S.: I've been exceptionally busy the last few weeks, and I'm way behind
in my list mail...  Now that E3 is over, I should have a little more time.


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