DiskOnChip 2000 read only file system

DiskOnChip 2000 read only file system

[Brian Peterson]

I am running a read only file system with a 64M Disk On Chip 2000 and want 
to know if anyone else has seen the problem I am having.

My system is a PC104 with a 64M DiskOnChip running linux kernel version 
2.4.20.
I have two partitions mounted: root is Read only and the other is 
Read/Write.

During some testing of power loss scenarios, I lose the ability to use the 
device. The kernel boots and after it cleans up from the unclean unmount, I 
receive kernel messages indicating
"Argh! No free blocks found!..."

What level of confidence is there that the read only partition would be 
protected from this problem. In other words, can the data located in the 
Read only partition be trusted?

Any feedback would be appreciated.

Brian Peterson

_________________________________________________________________
STOP MORE SPAM with the new MSN 8 and get 2 months FREE*  
http://join.msn.com/?page=features/junkmail

Re: DiskOnChip 2000 read only file system

[David Woodhouse]

purdue1996@hotmail.com said:
>  During some testing of power loss scenarios, I lose the ability to
> use the  device. The kernel boots and after it cleans up from the
> unclean unmount, I  receive kernel messages indicating "Argh! No free
> blocks found!..."

We should be able to fix this.

> What level of confidence is there that the read only partition would
> be  protected from this problem. In other words, can the data located
> in the  Read only partition be trusted? 

The data on the read only partition cannot be trusted any more than the 
data in the read-write partition. It's all in one big pseudo-filesystem, 
the partitioning is purely cosmetic.

--
dwmw2

Re: DiskOnChip 2000 read only file system

[Brian Peterson]

Is this a bug or is there something I did incorrectly?
or is there a utility I can use to correct this at runtime?

Thanks,
Brian


----Original Message Follows----
From: David Woodhouse <dwmw2@infradead.org>
To: "Brian Peterson" <purdue1996@hotmail.com>
CC: linux-mtd@lists.infradead.org
Subject: Re: DiskOnChip 2000 read only file system
Date: Thu, 30 Jan 2003 10:50:13 +0000


purdue1996@hotmail.com said:
 >  During some testing of power loss scenarios, I lose the ability to
 > use the  device. The kernel boots and after it cleans up from the
 > unclean unmount, I  receive kernel messages indicating "Argh! No free
 > blocks found!..."

We should be able to fix this.

 > What level of confidence is there that the read only partition would
 > be  protected from this problem. In other words, can the data located
 > in the  Read only partition be trusted?

The data on the read only partition cannot be trusted any more than the
data in the read-write partition. It's all in one big pseudo-filesystem,
the partitioning is purely cosmetic.

--
dwmw2



______________________________________________________
Linux MTD discussion mailing list
http://lists.infradead.org/mailman/listinfo/linux-mtd/


_________________________________________________________________
The new MSN 8: smart spam protection and 2 months FREE*  
http://join.msn.com/?page=features/junkmail

Re: DiskOnChip 2000 read only file system

[David Woodhouse]

purdue1996@hotmail.com said:
> Is this a bug or is there something I did incorrectly? or is there a
> utility I can use to correct this at runtime?

This is a bug. I'm not sure why it happens, but it shouldn't be that hard 
(for anyone) to fix, given sufficient time and motivation. The NFTL format 
isn't that complex.

--
dwmw2