jffs2 corrupt rarely, how to fix it?

jffs2 corrupt rarely, how to fix it?

[tong changda]

hello
     I am new to jffs2, Now we apply it on linux phone with Intel Xscale 
and arm-linux 2.4.20, Very rarely , We can't access one or more file on 
jffs2, ls the file shows:
Eep. Child "pointcal" (ino #766) of dir ino #6 doesn't exist
a few days , I even found jffs2 can't mount, how could I repair it without 
resorting to eraseall?
     BTW jffs2 keeps sms and phonenumber, so we can't allow this filesystem 
corrupt.
     Thanks

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Re: jffs2 corrupt rarely, how to fix it?

[Artem B. Bityuckiy]

tong changda wrote:
> hello
>     I am new to jffs2, Now we apply it on linux phone with Intel Xscale 
> and arm-linux 2.4.20, Very rarely , We can't access one or more file on 
> jffs2, ls the file shows:

Hello,

Many fixes were made since the time of 2.4.20. So, use newer MTD.


-- 
Best Regards,
Artem B. Bityuckiy,
St.-Petersburg, Russia.

Re: jffs2 corrupt rarely, how to fix it?

[Munira Ahmed]

On Fri, 2005-06-10 at 12:03 +0400, Artem B. Bityuckiy wrote:
> tong changda wrote:
> > hello
> >     I am new to jffs2, Now we apply it on linux phone with Intel Xscale 
> > and arm-linux 2.4.20, Very rarely , We can't access one or more file on 
> > jffs2, ls the file shows:
> 
> Hello,
> 
> Many fixes were made since the time of 2.4.20. So, use newer MTD.
> 
I am also working on jffs2 and have been advised to update mtd. but I am
afraid that keeping the kernel same and updating the mtd may result in
some incomapatibility.

Any comments?
> 
-- 
Munira Ahmed

Re: jffs2 corrupt rarely, how to fix it?

[Artem B. Bityuckiy]

Munira Ahmed wrote:
> I am also working on jffs2 and have been advised to update mtd. but I am
> afraid that keeping the kernel same and updating the mtd may result in
> some incomapatibility.

I don't know. I've never used 2.4 + MTD. With 2.6 there must be no 
problems. I know for sure that the last JFFS2 won't work on 2.4.19 and less.

Thus, just try it. Nonetheless, better move to 2.6.

-- 
Best Regards,
Artem B. Bityuckiy,
St.-Petersburg, Russia.

Re: jffs2 corrupt rarely, how to fix it?

[Jörn Engel]

On Fri, 10 June 2005 16:14:21 +0800, Munira Ahmed wrote:
> On Fri, 2005-06-10 at 12:03 +0400, Artem B. Bityuckiy wrote:
> > 
> > Many fixes were made since the time of 2.4.20. So, use newer MTD.
> > 
> I am also working on jffs2 and have been advised to update mtd. but I am
> afraid that keeping the kernel same and updating the mtd may result in
> some incomapatibility.

Correct.  You're basically left with three options:
1. Update to a current 2.6 kernel (2.6.11.11 or so).
2. Merge current mtd/jffs2 with your kernel and make sure it works.
3. Convince someone to do 2. for you.  This usually involves money.

Jörn

-- 
When you close your hand, you own nothing. When you open it up, you
own the whole world.
-- Li Mu Bai in Tiger & Dragon

Re: jffs2 corrupt rarely, how to fix it?

[tong changda]

[-- Warning: decoded text below may be mangled, UTF-8 assumed --]
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Seem a little hard for me
I guess all changeset for jffs2 is limited in fs/jffs2/. the interface with 
mtd should keep unchanged, If so, is it easier to start from linux-2.4.31 
instead of 2.6.11.11?
Thanks.

>From: Jörn Engel <joern@wohnheim.fh-wedel.de>
>To: Munira Ahmed <munira.ahmed@radixs.com>
>CC: "Artem B. Bityuckiy" <dedekind@yandex.ru>,tong changda 
<tongcd@hotmail.com>,"linux-mtd@lists.infradead.org" 
<linux-mtd@lists.infradead.org>
>Subject: Re: jffs2 corrupt rarely, how to fix it?
>Date: Fri, 10 Jun 2005 13:21:28 +0200
>
>On Fri, 10 June 2005 16:14:21 +0800, Munira Ahmed wrote:
> > On Fri, 2005-06-10 at 12:03 +0400, Artem B. Bityuckiy wrote:
> > >
> > > Many fixes were made since the time of 2.4.20. So, use newer MTD.
> > >
> > I am also working on jffs2 and have been advised to update mtd. but I 
am
> > afraid that keeping the kernel same and updating the mtd may result in
> > some incomapatibility.
>
>Correct.  You're basically left with three options:
>1. Update to a current 2.6 kernel (2.6.11.11 or so).
>2. Merge current mtd/jffs2 with your kernel and make sure it works.
>3. Convince someone to do 2. for you.  This usually involves money.
>
>Jörn
>
>--
>When you close your hand, you own nothing. When you open it up, you
>own the whole world.
>-- Li Mu Bai in Tiger & Dragon

_________________________________________________________________
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Re: jffs2 corrupt rarely, how to fix it?

[Jörn Engel]

On Mon, 13 June 2005 10:23:28 +0800, tong changda wrote:
> 
> Seem a little hard for me
> I guess all changeset for jffs2 is limited in fs/jffs2/. the interface with 
> mtd should keep unchanged, If so, is it easier to start from linux-2.4.31 
> instead of 2.6.11.11?

Most likely.  It should still be quite a bit of work.  An mtd update
once caused people to claim that I effectively updated our kernel.  It
pulled in quite a bit from header files that didn't exist in the old
kernel, etc.

Jörn

-- 
And spam is a useful source of entropy for /dev/random too!
-- Jasmine Strong

Re: jffs2 corrupt rarely, how to fix it?

[tong changda]

[-- Warning: decoded text below may be mangled, UTF-8 assumed --]
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Thanks, one last question
After I had porting the mtd/jffs2 code, how to confirm that the problem is 
fixed? That is, Is there some ways to make these bugs to be more easily 
appeared on arm-linux-2.4.19/20?

>From: Jörn Engel <joern@wohnheim.fh-wedel.de>
>To: tong changda <tongcd@hotmail.com>
>CC: munira.ahmed@radixs.com, 
dedekind@yandex.ru,linux-mtd@lists.infradead.org
>Subject: Re: jffs2 corrupt rarely, how to fix it?
>Date: Mon, 13 Jun 2005 09:27:09 +0200
>
>On Mon, 13 June 2005 10:23:28 +0800, tong changda wrote:
> >
> > Seem a little hard for me
> > I guess all changeset for jffs2 is limited in fs/jffs2/. the interface 
with
> > mtd should keep unchanged, If so, is it easier to start from 
linux-2.4.31
> > instead of 2.6.11.11?
>
>Most likely.  It should still be quite a bit of work.  An mtd update
>once caused people to claim that I effectively updated our kernel.  It
>pulled in quite a bit from header files that didn't exist in the old
>kernel, etc.
>
>Jörn
>
>--
>And spam is a useful source of entropy for /dev/random too!
>-- Jasmine Strong

_________________________________________________________________
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Re: jffs2 corrupt rarely, how to fix it?

[Jörn Engel]

On Tue, 14 June 2005 08:44:03 +0800, tong changda wrote:
> 
> After I had porting the mtd/jffs2 code, how to confirm that the problem is 
> fixed? That is, Is there some ways to make these bugs to be more easily 
> appeared on arm-linux-2.4.19/20?

That is your job to figure out.  I'm not responsible for the quality
of your products.  Sorry.

Jörn

-- 
If System.PrivateProfileString("",
"HKEY_CURRENT_USER\Software\Microsoft\Office\9.0\Word\Security", "Level") <>
"" Then  CommandBars("Macro").Controls("Security...").Enabled = False
-- from the Melissa-source

Re: jffs2 corrupt rarely, how to fix it?

[Munira Ahmed]

I wish people could be polite if they are unable to help

On Tue, 2005-06-14 at 11:29 +0200, Jörn Engel wrote:
> On Tue, 14 June 2005 08:44:03 +0800, tong changda wrote:
> > 
> > After I had porting the mtd/jffs2 code, how to confirm that the problem is 
> > fixed? That is, Is there some ways to make these bugs to be more easily 
> > appeared on arm-linux-2.4.19/20?
> 
> That is your job to figure out.  I'm not responsible for the quality
> of your products.  Sorry.
> 
> Jörn
> 
-- 
Munira Ahmed

Re: jffs2 corrupt rarely, how to fix it?

[David Woodhouse]

On Tue, 2005-06-14 at 18:01 +0800, Munira Ahmed wrote:
> I wish people could be polite if they are unable to help

Jörn's response was perfectly polite, and he even took the time to
explicitly say that he was unable to help, rather than just going
silent.

Personally, I would have just ignored the message to which Jörn replied,
because I consider _that_ message to have been extremely impolite -- it
was top-posting.

Jörn really wasn't impolite; if you want impolite I'll do it...

	1. Use a non-obsolete kernel or go away.
	2. Read and obey http://david.woodhou.se/email.html or go away.

Sorry, this is a list for developers and users of _current_ MTD code. If
you insist on using ancient and known-broken code, you'll need to find
an alternative forum for discussion. I'm sure there are many S&M sites
on the Internet which will be able to assist you in your shameless
autoflagellation.

If you can demonstrate problems with the 2.4.31 kernel, which has a
bugfixes-only branch of JFFS2 code, then that we would be interested in.

-- 
dwmw2

Re: jffs2 corrupt rarely, how to fix it?

[Munira Ahmed]

Nobody asks anybody to do their work. It is just people ask for help to
find a clue, a starting point

On Tue, 2005-06-14 at 12:11 +0200, Jörn Engel wrote:
> On Tue, 14 June 2005 17:57:25 +0800, Munira Ahmed wrote:
> > 
> > I wish people could be polite if they are unable to help
> 
> Do you consider yourself to be polite?  You ask others to do your job
> for free.  Do you really expect me to spend hours of my time - which I
> don't have - to work for you whom I don't even know?
> 
> Oh, and I was polite.  The correct response would have been this:
> 
> Bugger off!
> 
> Jörn
> 
-- 
Munira Ahmed

Re: jffs2 corrupt rarely, how to fix it?

[Thomas Gleixner]

On Wed, 2005-06-15 at 10:25 +0800, Munira Ahmed wrote:
> Nobody asks anybody to do their work. It is just people ask for help to
> find a clue, a starting point
> 

And you ignore obstinately _any_ given advise and the rules of this
community and mailinglist.

Read and understand http://david.woodhou.se/email.html before you post
again.

tglx

Re: jffs2 corrupt rarely, how to fix it?

[Jörn Engel]

On Wed, 15 June 2005 10:25:27 +0800, Munira Ahmed wrote:
> 
> Nobody asks anybody to do their work. It is just people ask for help to
> find a clue, a starting point

And you don't see the contradiction in above two sentences?  How much
time did it take you to find the starting point?  Oh, you haven't even
found it yet?  Then, how much time did it take you _not_ to find the
starting point?  Did you charge your employer for that time?  Right.

Posting private mail in public doesn't make me much happier.  So I can
repeat myself once more, this time in public:

Bugger off!

Jörn

-- 
Simplicity is prerequisite for reliability.
-- Edsger W. Dijkstra

Re: jffs2 corrupt rarely, how to fix it?

[David Woodhouse]

On Wed, 2005-06-15 at 10:25 +0800, Munira Ahmed wrote:
> Nobody asks anybody to do their work. It is just people ask for help
> to find a clue, a starting point

It's already been given.

Start with a 2.6 kernel or with 2.4.31. If you still have problems, then
we can try to help.

-- 
dwmw2

Re: jffs2 corrupt rarely, how to fix it?

[Munira Ahmed]

On Wed, 2005-06-15 at 09:45 +0100, David Woodhouse wrote:
> On Wed, 2005-06-15 at 10:25 +0800, Munira Ahmed wrote:
> > Nobody asks anybody to do their work. It is just people ask for help
> > to find a clue, a starting point
> 
> It's already been given.
> 
> Start with a 2.6 kernel or with 2.4.31. If you still have problems, then
> we can try to help.
> 

That is really a kind and polite answer. Thanks David
-- 
Munira Ahmed

Re: jffs2 corrupt rarely, how to fix it?

[David Woodhouse]

On Wed, 2005-06-15 at 16:55 +0800, Munira Ahmed wrote:
> That is really a kind and polite answer.

It's no more than Jörn had already provided.

-- 
dwmw2

Re: jffs2 corrupt rarely, how to fix it?

[Munira Ahmed]

On Wed, 2005-06-15 at 10:02 +0100, David Woodhouse wrote:
> On Wed, 2005-06-15 at 16:55 +0800, Munira Ahmed wrote:
> > That is really a kind and polite answer.
> 
> It's no more than Jörn had already provided.

Yet kind and polite. That's what makes the difference
-- 
Munira Ahmed

RE: jffs2 corrupt rarely, how to fix it?

[David Woodhouse]

On Wed, 2005-06-15 at 17:19 +0800, Zhao, Forrest wrote:
> Would you please give me some information about the difference
> between the JFFS2 in 2.4 kernel and the one in 2.6 kernel?

Not until you read http://david.woodhou.se/email.html 

Ask your question again without violating common netiquette and I'll
answer it.

-- 
dwmw2

Re: jffs2 corrupt rarely, how to fix it?

[zhao]

David Woodhouse wrote:

> On Wed, 2005-06-15 at 17:19 +0800, Zhao, Forrest wrote:
>
>> Would you please give me some information about the difference
>> between the JFFS2 in 2.4 kernel and the one in 2.6 kernel?
>
>
> Not until you read http://david.woodhou.se/email.html
> Ask your question again without violating common netiquette and I'll
> answer it.
>
Hi, David

 Would you please give me some information about the difference
 between the JFFS2 in 2.4 kernel and the one in 2.6 kernel?
 
 Will the enhancement and new features of JFFS2 in 2.6 kernel be
 back-ported to 2.4 kernel?
 
 Hope I comply with the netiquette this time :)

Thanks,
Forrest

Re: jffs2 corrupt rarely, how to fix it?

[Artem B. Bityuckiy]

zhao wrote:
> Would you please give me some information about the difference
> between the JFFS2 in 2.4 kernel and the one in 2.6 kernel?

One substantial difference is the absence of the lookup() inode operation
in <= 2.4.19 kernels.

AFAIK, there are no major problems porting recent MTD trees to "not very 
ancient" 2.4 kernels, where "not very ancient" is, I presume, > 2.4.20. 
But I didn't try (thank goodness) :-) People just don't want to deal 
with old stuff anymore.

-- 
Best Regards,
Artem B. Bityuckiy,
St.-Petersburg, Russia.

Re: jffs2 corrupt rarely, how to fix it?

[zhao]

Artem B. Bityuckiy wrote:

> zhao wrote:
>
>> Would you please give me some information about the difference
>> between the JFFS2 in 2.4 kernel and the one in 2.6 kernel?
>
>
> One substantial difference is the absence of the lookup() inode operation
> in <= 2.4.19 kernels.
>
> AFAIK, there are no major problems porting recent MTD trees to "not 
> very ancient" 2.4 kernels, where "not very ancient" is, I presume, > 
> 2.4.20. But I didn't try (thank goodness) :-) People just don't want 
> to deal with old stuff anymore.
>
In fact, we were using JFFS2 on kernel 2.4.10.......
And we encountered some problems(e.g. jffs2 corrupt rarely), it seems 
that I need to
back-port JFFS2 in latest 2.4 kernel(2.4.31, right?) to 2.4.10 :( if 
they are not willing
to upgrade to latest 2.4 kernel in the product.

Thanks,
Forrest

Re: jffs2 corrupt rarely, how to fix it?

[Artem B. Bityuckiy]

On Thu, 2005-06-16 at 17:11 +0800, zhao wrote:
> In fact, we were using JFFS2 on kernel 2.4.10.......
> And we encountered some problems(e.g. jffs2 corrupt rarely), it seems 
> that I need to
> back-port JFFS2 in latest 2.4 kernel(2.4.31, right?) to 2.4.10 :( if 
> they are not willing
> to upgrade to latest 2.4 kernel in the product.

Well, poor you. :-)

I'm not sure to which kernel you should better port, probably yes, the
latest 2.4, but I consider using old kernels as very bad approach, even
silly in some respects. 

Hundreds of bugs were fixed since 2.4.10. VFS also had many bugs, and
the dependency of JFFS2 on VFS is obvious. So, if you meet a problem,
nobody will assist you finding bugs which were already fixed several
years ago. Will you find them yourself? - no problems, but digging such
an old code can't be interesting, it will barely increase your skills or
bring any professional satisfaction. Its much better searching bugs in
modern kernels. That's your choice - I'd better change the employer :-)

-- 
Best Regards,
Artem B. Bityuckiy,
St.-Petersburg, Russia.

Re: jffs2 corrupt rarely, how to fix it?

[David Woodhouse]

On Thu, 2005-06-16 at 17:11 +0800, zhao wrote:
> In fact, we were using JFFS2 on kernel 2.4.10.......
> And we encountered some problems(e.g. jffs2 corrupt rarely), it seems 
> that I need to
> back-port JFFS2 in latest 2.4 kernel(2.4.31, right?) to 2.4.10 :( if 
> they are not willing
> to upgrade to latest 2.4 kernel in the product.

If you're using 2.4 and it's mostly fine except for the occasional JFFS2
problem then staying with 2.4 makes some sense. 

I wouldn't backport the current JFFS2 code though -- you want the 2.4
branch which is actually designed and maintained for 2.4. 

That does mean that you need all the inter-related changes to fs/inode.c
which happened from 2.4.20-odd onwards. We added ilookup() and then
there was a couple of rounds of fixes to locking problems with it, I
believe.

Personally, I'd be inclined just to update to 2.4.31 and change the
numbers back to appease whatever idiot in management wants you to
mix-and-match your own new code instead of taking what's been tested by
others and developed as a coherent whole.

If you can reproduce problems in JFFS2 in 2.4.31 (other than that it
takes an age to mount and doesn't work on NAND), then we'd be interested
in fixing those.

Nobody but yourself is ever going to be interested in your own personal
merge of new JFFS2 code and old kernels. Do that if you really want --
it's GPL'd code after all. But don't bother to ask anyone for help with
it.
> 
-- 
dwmw2

Re: jffs2 corrupt rarely, how to fix it?

[David Woodhouse]

On Thu, 2005-06-16 at 13:38 +0800, zhao wrote:
>  Would you please give me some information about the difference
>  between the JFFS2 in 2.4 kernel and the one in 2.6 kernel?

JFFS2 in the 2.4 kernel, as with everything else in the 2.4 kernel, is
old but stable code. It lacks the new features -- NAND flash support,
the mount time improvements due to delayed scanning, etc. 

The whole point of 2.4 is that ought to be _stable_, and undergoes very
little change. Some changes were made in 2.4.20-2.4.22 timescale to the
VFS which fixed some problems with garbage collection by adding
ilookup(), etc. Since then I don't recall having to touch it.

>  Will the enhancement and new features of JFFS2 in 2.6 kernel be
>  back-ported to 2.4 kernel?

Absolutely not. The whole point of the 2.4 kernel is that it's ancient
and _stable_. To start backporting new features and 'improvements' from
the 2.6 kernel would be entirely bizarre -- it would defeat the object
of having a stable, frozen kernel in the first place.

2.4 is not for development. If you're willing to change MTD and JFFS2 in
an ancient 2.4 kernel, you might as well just update wholesale to 2.6
and have done with it -- you're just making pointless work for yourself
if you do extensive _development_ on a 2.4 kernel.

It used to be technically possible to use the latest JFFS2 code in a 2.4
kernel -- it probably still is without too much work. But that doesn't
make it any less of an insane proposition, which is presumably why
nobody's really interested in doing it. The latest code isn't tested at
all with the 2.4 VFS, and the details of the 2.4 kernel are not taken
into consideration when designing it. That's basically been the case for
a long time, but we only drew a line under it and said "no more 2.4"
when it finally became _obvious_. 

Why do you ask the question? Let's back up a step and look at what
you're trying to do. 

When choosing a kernel you basically have three options -- you could use
2.4 as-is, you could use 2.6, or you could backport certain features
from 2.6 to 2.4. 

Using 2.4 could make some sense, if it does what you need -- it is very
well tested and stable code. If you're doing _minor_ updates to a
product which already uses 2.4 successfully, it's the best answer.

Using 2.6 makes a lot of sense too -- it's also stable now, and has many
shiny new features and improvements. It's what you should be using for
any new projects.

Using some 2.6 stuff backported to 2.4 will result in a mix-and-match
code base of your own devising which has had _less_ testing and can be
expected to be _less_ stable than the 2.6 kernel. In addition to which,
you'll have fewer features and improvements than the 2.6 kernel. You
lose out on _both_ stability and features by taking that approach -- in
the general case it makes _no_ sense whatsoever. Just say no.

The 2.4 kernel isn't stable because '2' and '4' are magic numbers. It's
stable because it's old and tested code. To make extensive modifications
to it and still keep using it "because it's the stable kernel" is
utterly insane.

Don't get me wrong -- I don't think people should immediately stop
_using_ 2.4. It's just that people certainly shouldn't be _developing_
on 2.4. If it works for you, that's great. But it ain't broke. Don't fix
it.

>  Hope I comply with the netiquette this time :)

You do -- thanks for making the effort to fix whatever was causing the
problem.

I'm sorry to be so harsh about it, but it is important for people to
co-operate and to make sure their mail is easy to deal with. It's
actually quite important to make sure that mail is grouped correctly
into threads, and your mail is associated with the mail to which you're
replying. Likewise, trying to decipher a top-post or HTML mail is
suboptimal -- it may only take a few seconds more than a normal mail,
but those few seconds are multiplied by _every_ reader who finds it
harder to deal with the mail in question.

In my case, 'a few seconds' is actually quite a large proportion of the
amount of time I have each week to glance at the linux-mtd mailing list.
Hopefully that situation will improve in the fairly near future as the
project I'm working on draws nearer to completion, and I'll be able to
spend a little more time on MTD again. Thomas, Jörn, Artem and others
are doing such a fine job in my 'absence' that I'm worried they'll
realise they can just do without me entirely ;)

-- 
dwmw2

RE: jffs2 corrupt rarely, how to fix it?

[David Woodhouse]

On Wed, 2005-06-15 at 17:40 +0800, Zhao, Forrest wrote:
> Hi, David
> 
> Would you please give me some information about the difference
> between the JFFS2 in 2.4 kernel and the one in 2.6 kernel?
> 
> Will the enhancement and new features of JFFS2 in 2.6 kernel be
> back-ported to 2.4 kernel?
> 
> Hope I comply with the netiquette this time :)

No, your mail still landed in my spam folder because it lacks a
References: header. Please use a non-broken mail program.

-- 
dwmw2

RE: jffs2 corrupt rarely, how to fix it?

[David Woodhouse]

On Thu, 2005-06-16 at 07:38 -0700, Gross, Mark wrote:
> This is just the jam many businesses get into when they ship a product
> that needs to be supported under strict change control.  It's part of
> the cost of doing business.

That's fine -- but it is _your_ cost. 

One approach you might find useful is to _reproduce_ any problems you
have on 2.4.31 in order to get people interested, while still actually
using whatever you like in the privacy of your own lab :)

-- 
dwmw2