Compiling JFFS3

Compiling JFFS3

[Bernhard Priewasser]

Hello,

when trying to compile JFFS3 kernel module out-of-the-box, I get 
(pathnames stripped):

 > ~/mtd/fs/jffs3> make
 > make -C /lib/modules/2.6.11.4-21.7-default/build SUBDIRS=`pwd` 
mtd=`pwd` modules
 > make[1]: Entering directory `/usr/src/linux-2.6.11.4-21.7'
 >   CC [M]  /mtd/fs/jffs3/compr.o
 > In file included from /mtd/fs/jffs3/nodelist.h:205,
 >                  from /mtd/fs/jffs3/compr.h:27,
 >                  from /mtd/fs/jffs3/compr.c:17:
 > /mtd/fs/jffs3/debug.h: In function `jffs3_dbg_wbuf_acct_sanity_check':
 > /mtd/fs/jffs3/debug.h:366: error: structure has no member named 
`wbuf_pagesize'
 > /mtd/fs/jffs3/debug.h:366: error: structure has no member named 
`wbuf_len'
 > /mtd/fs/jffs3/debug.h:367: error: structure has no member named 
`wbuf_ofs'
 > /mtd/fs/jffs3/debug.h:367: error: structure has no member named 
`wbuf_len'
 > /mtd/fs/jffs3/debug.h:367: error: structure has no member named 
`wbuf_pagesize'
 > /mtd/fs/jffs3/debug.h:367: error: structure has no member named 
`wbuf_len'
 > make[2]: *** [/mtd/fs/jffs3/compr.o] Error 1
 > make[1]: *** [_module_/mtd/fs/jffs3] Error 2
 > make[1]: Leaving directory `/usr/src/linux-2.6.11.4-21.7'
 > make: *** [modules] Error 2

In jffs3.h, line 296ff, the write-behind and oob stuff (wbuf_* ...) is 
not added because CONFIG_JFFS3_FS_WRITEBUFFER is not defined.

Have a look at mtd/include/linux/config.h, line 38. Shouldn't
 > #define CONFIG_JFFS3_FS_WRITEBUFFER 1
be added there to consider JFFS_3_ too, not only JFFS_2_?

Regards,
Bernhard

Re: Compiling JFFS3

[Jörn Engel]

On Wed, 10 August 2005 10:26:28 +0200, Bernhard Priewasser wrote:
> 
> when trying to compile JFFS3 kernel module out-of-the-box, I get 
> (pathnames stripped):

That's expected.  JFFS3 was an attempt that didn't work out.  Unless
you are willing to spend several month of full time on the project,
just forget about it and use JFFS2 instead.

I guess we should remove that whole tree soon, before more people are
getting confused.

Jörn

-- 
Man darf nicht das, was uns unwahrscheinlich und unnatürlich erscheint,
mit dem verwechseln, was absolut unmöglich ist.
-- Carl Friedrich Gauß

Re: Compiling JFFS3

[Bernhard Priewasser]

Jörn Engel wrote:
 > That's expected.  JFFS3 was an attempt that didn't work out.  Unless
 > you are willing to spend several month of full time on the project,
 > just forget about it and use JFFS2 instead.
 >
 > I guess we should remove that whole tree soon, before more people are
 > getting confused.

Oh... seems I'm not up to date about the JFFS2/3/... ongoing, sorry.
I thought JFFS3 was intended basically containing Artem's improvements.
So what about "future" issues like scaling on large flashes and the 
other nice JFFS3 stuff?

Bernhard

Re: Compiling JFFS3

[Artem B. Bityuckiy]

Bernhard Priewasser wrote:
> Oh... seems I'm not up to date about the JFFS2/3/... ongoing, sorry.
> I thought JFFS3 was intended basically containing Artem's improvements.
> So what about "future" issues like scaling on large flashes and the 
> other nice JFFS3 stuff?
> 
That's the old attempt to create a new flash FS with a JFFS2-like 
design. I've given up doing this and working on another JFFS3 design 
(see doc on MTD site). I did not implement my mew ideas. Thus, the old 
jffs3 must be removed.

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

Re: Compiling JFFS3

[Bernhard Priewasser]

Artem B. Bityuckiy wrote:
> That's the old attempt to create a new flash FS with a JFFS2-like 
> design. I've given up doing this and working on another JFFS3 design 
> (see doc on MTD site). I did not implement my mew ideas. Thus, the old 
> jffs3 must be removed.

Ferenc Havasi's improvements are doing well? Confusing...

Re: Compiling JFFS3

[Artem B. Bityuckiy]

Bernhard Priewasser wrote:
> Ferenc Havasi's improvements are doing well? Confusing...
> 
His improvements are going to go into JFFS2 AFAIK

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

Re: Compiling JFFS3

[Bernhard Priewasser]

Artem B. Bityuckiy wrote:
> Bernhard Priewasser wrote:
>> Ferenc Havasi's improvements are doing well? Confusing...
> His improvements are going to go into JFFS2 AFAIK

Ah, OK. To sum up (for my understanding): Ferenc's improvements (mount 
time, compression) were - beside others - part of JFFS3. JFFS3 design in 
its current form is not satisfactory, it will be cancelled. Anyway, 
Ferenc's improvements are good and should/will be merged into JFFS2.
In parallel, there are some ideas for solving JFFS2 problems like 
described in the (very nice) "JFFS3 design issues" (scaling: mount time, 
memory consumption, access time). This will be the "new" JFFS3, current 
solutions for scaling and stuff are not available or not satisfactory.
Correct until now? Still a bit confusing :)

Bernhard

Re: Compiling JFFS3

[Artem B. Bityuckiy]

On Wed, 2005-08-10 at 11:31 +0200, Bernhard Priewasser wrote:
> Ah, OK. To sum up (for my understanding): Ferenc's improvements (mount 
> time, compression) were - beside others - part of JFFS3. JFFS3 design in 
> its current form is not satisfactory, it will be cancelled. Anyway, 
> Ferenc's improvements are good and should/will be merged into JFFS2.
> In parallel, there are some ideas for solving JFFS2 problems like 
> described in the (very nice) "JFFS3 design issues" (scaling: mount time, 
> memory consumption, access time). This will be the "new" JFFS3, current 
> solutions for scaling and stuff are not available or not satisfactory.
> Correct until now? Still a bit confusing :)
> 
Agree :-)

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

Re: Compiling JFFS3

[Bernhard Priewasser]

Artem B. Bityuckiy wrote:
> Agree :-)
Fine! Finally I got it.

So, WHEN will there be a fast, robust JFFS3? :-)
It's a pity that JFFS2 lags a bit with these scaling things.

Bernhard

Re: Compiling JFFS3

[Artem B. Bityuckiy]

Bernhard Priewasser wrote:
> So, WHEN will there be a fast, robust JFFS3? :-)
> It's a pity that JFFS2 lags a bit with these scaling things.
> 
Who knows. I'm working on this in background. Too much work for one 
person. First I hope to create (1) a good design, (2) a small and 
primitive implementation just to get sure my ideas are implentable.

Then more people may join me or somebody may sponsor the further 
development.

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

Re: Compiling JFFS3

[Jörn Engel]

On Wed, 10 August 2005 11:31:44 +0200, Bernhard Priewasser wrote:
>
> To: linux-mtd@lists.infradead.org

Please always reply to all.  I hate to miss interesting stuff, just
because some idiot removed me from the Cc: list.

[ For political correctness' sake.  I didn't call you an idiot yet.
Only if you _continue_ to misbehave in this way, I _will_ call you
that.  So please... ;) ]

> Artem B. Bityuckiy wrote:
> >Bernhard Priewasser wrote:
> >>Ferenc Havasi's improvements are doing well? Confusing...
> >His improvements are going to go into JFFS2 AFAIK
> 
> Ah, OK. To sum up (for my understanding): Ferenc's improvements (mount 
> time, compression) were - beside others - part of JFFS3. JFFS3 design in 
> its current form is not satisfactory, it will be cancelled. Anyway, 
> Ferenc's improvements are good and should/will be merged into JFFS2.
> In parallel, there are some ideas for solving JFFS2 problems like 
> described in the (very nice) "JFFS3 design issues" (scaling: mount time, 
> memory consumption, access time). This will be the "new" JFFS3, current 
> solutions for scaling and stuff are not available or not satisfactory.
> Correct until now? Still a bit confusing :)

The name "JFFS3" ist confusing.  For that very reason, I consider it
rightout harmful to call anything "JFFS3".  Artem has a different
opinion.  It's a free world, everyone has the right to be wrong, if he
so desires. ;)

JFFS has a strictly log-structured design.  JFFS2 is still
log-structured, although not strictly anymore.  You could call it a
chaptered log - strictly log-structured within a chapter, completely
independent chapters.  JFFS3 (the old one, which Artem just removed)
was still supposed to be log-structured.  So the name made sense.  It
was similar in design.

The next flash FS, whatever it will look like, will not be log
structure anymore.  At least, noone I know of is trying to follow that
road anymore.  Log-structuring simply doesn't scale.  Therefore, this
fundamental change in design should not be hidden behind a name like
"JFFS3" - especially since it could also describe the last, failed
approach.

Jörn

-- 
Schrödinger's cat is <BLINK>not</BLINK> dead.
-- Illiad

Re: Compiling JFFS3

[Steven Scholz]

Jörn,

> The name "JFFS3" ist confusing...
> 
> JFFS has a strictly log-structured design.  JFFS2 is still
> log-structured,

log-structured == journaling ?

--
Steven

Re: Compiling JFFS3

[Bernhard Priewasser]

Steven Scholz wrote:
> log-structured == journaling ?

log-structured = full data journaling. I think.

Bernhard

Re: Compiling JFFS3

[Jörn Engel]

On Wed, 10 August 2005 12:14:15 +0200, Steven Scholz wrote:
> 
> >The name "JFFS3" ist confusing...
> >
> >JFFS has a strictly log-structured design.  JFFS2 is still
> >log-structured,
> 
> log-structured == journaling ?

Not really, but opinions differ on this subject.

A journal is basically the same as a log.  But a journaled fs has the
journal/log _in addition_ to some other data layout.  A log-structured
fs _only_ has the journal/log.

JFFS2 is log-structured and the name is a bug, imo.  My personal
implementation of a JFFS2 successor is called LOGFS, btw.  It makes
perfect sence, since LOGFS is just as log-structured as JFFS2 is
journaled - not at all. ;)

Jörn

-- 
Ninety percent of everything is crap.
-- Sturgeon's Law

Re: Compiling JFFS3

[Steven Scholz]

Jörn Engel wrote:

> On Wed, 10 August 2005 12:14:15 +0200, Steven Scholz wrote:
> 
>>>The name "JFFS3" ist confusing...
>>>
>>>JFFS has a strictly log-structured design.  JFFS2 is still
>>>log-structured,
>>
>>log-structured == journaling ?
> 
> 
> Not really, but opinions differ on this subject.
> 
> A journal is basically the same as a log.  But a journaled fs has the
> journal/log _in addition_ to some other data layout.  A log-structured
> fs _only_ has the journal/log.
> 
> JFFS2 is log-structured and the name is a bug, imo.  My personal
> implementation of a JFFS2 successor is called LOGFS, btw.  It makes
> perfect sence, since LOGFS is just as log-structured as JFFS2 is
> journaled - not at all. ;)

;-)

However, I hope the new name will be easier pronouncable! ;-)

--
Steven

Re: Compiling JFFS3

[Artem B. Bityuckiy]

Steven Scholz wrote:
> However, I hope the new name will be easier pronouncable! ;-)

JFFS3 sounds cute and is pronounced easily, isn't it ? :-)

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

Re: Compiling JFFS3

[Steven Scholz]

Artem B. Bityuckiy wrote:

> Steven Scholz wrote:
> 
>> However, I hope the new name will be easier pronouncable! ;-)
> 
> 
> JFFS3 sounds cute and is pronounced easily, isn't it ? :-)

Well. Maybe for a russian tounge! ;-) I ask my colleague.

Shell we start looking for a new name before doing any design ... ;-)

--
Steven

Re: Compiling JFFS3

[Artem B. Bityuckiy]

Steven Scholz wrote:
> Shell we start looking for a new name before doing any design ... ;-)
Hehe, good joke :-)

First let's make something worthy, then we will call it somehow :-)

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

Re: Compiling JFFS3

[Jörn Engel]

On Wed, 10 August 2005 12:37:44 +0200, Steven Scholz wrote:
> 
> Shell we start looking for a new name before doing any design ... ;-)

Too late, design has already started in April. :-P

But some people have suggested a different name for logfs.  My current
list includes:

logfs
jffs3
jefs
engelfs
poofs
crapfs
sweetfs
cutefs

Feel free to add more.  I don't have a strong preference, although
some may be crappy advertisement. ;)

Jörn

-- 
A quarrel is quickly settled when deserted by one party; there is
no battle unless there be two.
-- Seneca

Re: Compiling JFFS3

[Jared Hulbert]

jefs

:)  Easy for an American to say anyway.

Either way is the source up somewhere we can look at it?

On 8/10/05, Jörn Engel <joern@wohnheim.fh-wedel.de> wrote:
> On Wed, 10 August 2005 12:37:44 +0200, Steven Scholz wrote:
> >
> > Shell we start looking for a new name before doing any design ... ;-)
> 
> Too late, design has already started in April. :-P
> 
> But some people have suggested a different name for logfs.  My current
> list includes:
> 
> logfs
> jffs3
> jefs
> engelfs
> poofs
> crapfs
> sweetfs
> cutefs
> 
> Feel free to add more.  I don't have a strong preference, although
> some may be crappy advertisement. ;)
> 
> Jörn
> 
> --
> A quarrel is quickly settled when deserted by one party; there is
> no battle unless there be two.
> -- Seneca
> 
> ______________________________________________________
> Linux MTD discussion mailing list
> http://lists.infradead.org/mailman/listinfo/linux-mtd/
>

Re: Compiling JFFS3

[Josh Boyer]

On Fri, 2005-08-12 at 13:27 -0700, Jared Hulbert wrote:
> jefs
> 
> :)  Easy for an American to say anyway.
> 
> Either way is the source up somewhere we can look at it?

No, Jörn is currently working in "man in the closet" mode :).  At least
I haven't been able to get code out of him yet.

josh

Re: Compiling JFFS3

[Jörn Engel]

On Fri, 12 August 2005 13:27:33 -0700, Jared Hulbert wrote:
> 
> jefs
> 
> :)  Easy for an American to say anyway.

Voting period hasn't started yet, but I'll try to remember.

> Either way is the source up somewhere we can look at it?

Not yet.  First I want to get the basic functionality done.  It
doesn't have to be complete, but it has to do "something" well before
I send it out.

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: Compiling JFFS3

[Bernhard Priewasser]

Jörn Engel wrote:
> Please always reply to all.  I hate to miss interesting stuff, just
> because some idiot removed me from the Cc: list.
Better now? ;-)

 > The next flash FS, whatever it will look like, will not be log
 > structure anymore.  At least, noone I know of is trying to follow that
 > road anymore.  Log-structuring simply doesn't scale.
But log-structuring and handling failsafe issues works comfortable and 
reliable... What's another solution, in matters of (a) robustness and 
(b) scaling?

Bernhard

Re: Compiling JFFS3

[Jörn Engel]

On Wed, 10 August 2005 12:36:53 +0200, Bernhard Priewasser wrote:
> Jörn Engel wrote:
> >Please always reply to all.  I hate to miss interesting stuff, just
> >because some idiot removed me from the Cc: list.
> Better now? ;-)

Much, thank you.

> > The next flash FS, whatever it will look like, will not be log
> > structure anymore.  At least, noone I know of is trying to follow that
> > road anymore.  Log-structuring simply doesn't scale.
>
> But log-structuring and handling failsafe issues works comfortable and 
> reliable... What's another solution, in matters of (a) robustness and 
> (b) scaling?

Artem has described some of the necessary bits in his JFFS3 document.
Ignoring the name, it is quite useful as an introduction.

Basic design must be tree-structured, just like ext2 and all the other
well-known filesystems for hard disks.  Main difference to ext2 is the
requirement for out-of-place updates and garbage collection.

Most of the ugly details can be derived from these three simple
principles.

Jörn

-- 
Beware of bugs in the above code; I have only proved it correct, but
not tried it.
-- Donald Knuth

Re: Compiling JFFS3

[Artem B. Bityuckiy]

Jörn Engel wrote:
> That's expected.  JFFS3 was an attempt that didn't work out.  Unless
> you are willing to spend several month of full time on the project,
> just forget about it and use JFFS2 instead.
> 
> I guess we should remove that whole tree soon, before more people are
> getting confused.
> 
Yeah, the jffs3 tree under MTD CVS is the first attempt to improve 
JFFS2. Now it should be removed.

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