Status of HFS+ support

Status of HFS+ support

[Halfmann, Klaus]

Today I can announce a bit of progress:

The following tools currently work (readonly):

hpmount ,hpumount, hpls, hpcd, hpcopy.

They are really fresh and propably full of bugs, but I was able
to copy a file from a HFS+ volume (my major goal). Everybody
interested can ask me about the anoymous CVS acces at Suse
(thanks once again), or even better might help me :). And
yes, It should run ox x86 linux, too. But I have no acces to
a machine to really test it. (On the other hand, which x86
linux user needs this :)

I hope Suse will either provide rsync access or even
prebuild the tools. If someone volunteers I can provide the
statically linked tools to be put on some web/ftp site.

My next short-term goals are debugging the tools and begin
writing the cache I'll need for write acces later.

P.S. could someone tell me how to join the linux-fsdevel
	List ? (or better read it offline)

Greetings,

|       |                  Klaus Halfmann       khalfmann@libra.de
|       |
|    i  | --.  r---  -- |  Libra Software GmbH  Tel +49 (0)621 41997-0
|    |  b-- |  |    a-- |  Erzbergerstr. 17     Fax +49 (0)621 41997-30
L--- |  --- |  |    .---.  68165 Mannheim

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Re: Status of HFS+ support

[Alexander Viro]

On Fri, 15 Sep 2000, Halfmann, Klaus wrote:

> (thanks once again), or even better might help me :). And
> yes, It should run ox x86 linux, too. But I have no acces to
> a machine to really test it. (On the other hand, which x86
> linux user needs this :)

Put several fs images on anon ftp and let's see what testing can be
done...

> P.S. could someone tell me how to join the linux-fsdevel
> 	List ? (or better read it offline)

Huh? It's majordomo-controlled. I.e. mail to majordomo@vger.... and put
subscribe linux-fsdevel
into body. Then reply to the confirmation request - all as usual.

ObTesting: folks, it's share-the-testsuite time. Really. Everyone who has
such stuff is very welcome to post URLs.

ObTesting2: any volunteers for testing new minixfs? It looks like I've got
something that approaches beta. I'll put it on anon-ftp tonight and post
the URL - it may be dangerous, so don't try it on production boxen...
It should fix the races analogous to ext2 ones.


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Re: Status of HFS+ support

[Juan J. Quintela]

>>>>> "viro" == Alexander Viro <viro@math.psu.edu> writes:

Hi

viro> ObTesting: folks, it's share-the-testsuite time. Really. Everyone who has
viro> such stuff is very welcome to post URLs.

I am doing a testsuite for the memory system, at the URL:

http://carpanta.dc.fi.udc.es/~quintela/memtest/

I have found that a lot of the tests are also for the filesystem.

If you have some other tests/<whatever> for inclusion, send me a copy
and I will include it there ...

Later, Juan.

--
In theory, practice and theory are the same, but in practice they
are different -- Larry McVoy

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Re: Status of HFS+ support

[Geert Uytterhoeven]

On Fri, 15 Sep 2000, Halfmann, Klaus wrote:
> Today I can announce a bit of progress:
>
> The following tools currently work (readonly):
>
> hpmount ,hpumount, hpls, hpcd, hpcopy.

No hpfsck (or even a hpvalidate)? Having a tool to _verify_ (I'm not speaking
about correcting yet) the correctness of a filesystem is very interesting.

Gr{oetje,eeting}s,

						Geert

--
Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@linux-m68k.org

In personal conversations with technical people, I call myself a hacker. But
when I'm talking to journalists I just say "programmer" or something like that.
							    -- Linus Torvalds


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Re: Status of HFS+ support

[Tony Mantler]

At 8:07 AM -0500 9/15/2000, Geert Uytterhoeven wrote:
>On Fri, 15 Sep 2000, Halfmann, Klaus wrote:
>> Today I can announce a bit of progress:
>>
>> The following tools currently work (readonly):
>>
>> hpmount ,hpumount, hpls, hpcd, hpcopy.
>
>No hpfsck (or even a hpvalidate)? Having a tool to _verify_ (I'm not speaking
>about correcting yet) the correctness of a filesystem is very interesting.

Checking an hfs or hfs+ filesystem is very very easy.

I could picture walking down the catalog btree and check to see that the
sidelinks and downlinks all agree on which node they're pointing at, and
while you're at it, make sure the nodes don't point to garbage.

You'd then probably repeat that procedure on the Extents btree.

After that's done, you'd probably walk the leaf nodes of the catalog tree
to check that the filesystem heiarchy is still sane. After that, it would
probably follow to walk the leaf nodes in the extents btree and check for
overlaps, then compare it with the volume bitmap.

There's probably a few other checks that would be good too, like checking
for stale extents records or something.

Repairing an HFS(+) drive is a whole other matter entirely. Saying "This
ain't no journaling filesystem" would be an understatement of galactic
proportions (which, I should add, would also make threading the filesystem
very painful). Consider that when you insert a new leaf node into one of
the btrees, you have at the absolute very least 5 pointers to update. Power
goes out? oops, now 2 of those pointers are pointing at one node, and 2 are
pointing at some other node, and one's full of garbage 'cause the HD didn't
get a chance to write out the whole node. Which pointers are correct? who
knows, I don't think apple ever documented a prefered serialization order
for any of the fs changes.

imho, the only reliable way to repair a crashed HFS(+) drive is with a hex
editor.


Cheers - Tony 'Nicoya' Mantler :)


--
Tony "Nicoya" Mantler - Renaissance Nerd Extraordinaire - nicoya@apia.dhs.org
Winnipeg, Manitoba, Canada           --           http://nicoya.feline.pp.se/


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Re: Status of HFS+ support

[flar]

Tony Mantler wrote:
> Checking an hfs or hfs+ filesystem is very very easy.

Well, I don't know that I'd call it very easy, but it's certainly easier
than trying to actually fix it. :)

> I could picture walking down the catalog btree and check to see that the
> sidelinks and downlinks all agree on which node they're pointing at, and
> while you're at it, make sure the nodes don't point to garbage.
>
> You'd then probably repeat that procedure on the Extents btree.
>
> After that's done, you'd probably walk the leaf nodes of the catalog tree
> to check that the filesystem heiarchy is still sane. After that, it would
> probably follow to walk the leaf nodes in the extents btree and check for
> overlaps, then compare it with the volume bitmap.
>
> There's probably a few other checks that would be good too, like checking
> for stale extents records or something.

That all sounds reasonable. Probably wouldn't even take that long, and
would likely prove the correctness or incorrectness of the code in some
instances. The thing that would be a pain to check but very important
is to check the sorting order in all trees. I may even try to get something
running this weekend if I get a chance.

> Repairing an HFS(+) drive is a whole other matter entirely. Saying "This
> ain't no journaling filesystem" would be an understatement of galactic
> proportions (which, I should add, would also make threading the filesystem
> very painful). Consider that when you insert a new leaf node into one of
> the btrees, you have at the absolute very least 5 pointers to update. Power
> goes out? oops, now 2 of those pointers are pointing at one node, and 2 are
> pointing at some other node, and one's full of garbage 'cause the HD didn't
> get a chance to write out the whole node. Which pointers are correct? who
> knows, I don't think apple ever documented a prefered serialization order
> for any of the fs changes.

Yes, it is a bit of a mess.

> imho, the only reliable way to repair a crashed HFS(+) drive is with a hex
> editor.

Well, automated tools can fix some of the damage. I've had good luck fixing
drives with Norton Utilities, although there are some problems it chokes on.

	Brad Boyer
	flar@pants.nu


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Status of HFS+ Support

[Halfmann, Klaus]

I hope you dont mind me posting this here,
I can't imagine a better place right now.

In cooperation with Suse (thanks to Olaf Hering and other People at Suse),
we have set up an CVS repository for the hfsplus stuff.
Olaf Hering, some Suse internal and I have write access and there is an
anonymous access,too.

The hfsplus tools _shall_ work like the hfsutils (from rob@mars.org)
once I get so far. Currently Im stuck in grasping the B*-Tree structure
and it may take a while until I have presentable progress. I can only
spare some hours at the weekend (and my wife would like to get some time,
too) or when traveling to work by train.

Meanwhile everybody interested may help me in some of the following ways:

	Provide HFS+ formatted images with known content.
	(via mounting a ramdisk in MOL, thanks to BenH for this tip)

	Review my code (The code for the allocation bitmap does'nt work,
	but I dont know why, yet).

	Help pushing this thing foreward.

Whoever is interestet in the anoymous access can mail Olaf Hering or me.
In case there is overwhelming interest I'll post it here
I'll be happy to accepts comments and diffs agains the cvs tree.

Greeting,

|       |                  Klaus Halfmann       khalfmann@libra.de
|       |				  			(aka Hasi)
|    i  | --.  r---  -- |  Libra Software GmbH  Tel +49 (0)621 41997-0
|    |  b-- |  |    a-- |  Erzbergerstr. 17     Fax +49 (0)621 41997-30
L--- |  --- |  |    .---.  68165 Mannheim

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