How to update UBIFS while running an application ?

How to update UBIFS while running an application ?

[Manuel Sahm]

Hello,
 
I have 3 UBIFS mounted - one is the RFS, another one is mounted in
/mnt/ubi1/ and the last one is mounted in /mnt/ubi2/
My main application is in /mnt/ubi1/ and is running.
 
How could I update the actual ubifs ubi0_0, ubi1_0 and ubi2_0 ?
 
I tried ist with 
1.) flash_eraseall
2.) nandwrite
---> This doesn´t work -> after restart I got errors -> RFS is damaged
and doesn´t boot anymore
 
another try:
1.) ubiupdatevol
-----> the problem - this program doesn´t work if the ubifs is mounted
- but I can´t unmount /mnt/ubi1 or /mnt/ubi2 or the RFS because there
are applications running.
 
 
So what can I do to solve this problem ?
 
Thank you

Re: How to update UBIFS while running an application ?

[Artem Bityutskiy]

Hi,

I could not chat to you because my client died, sorry.

On Fri, 2009-04-03 at 14:53 +0200, Manuel Sahm wrote:
> Hello,
>  
> I have 3 UBIFS mounted - one is the RFS, another one is mounted in
> /mnt/ubi1/ and the last one is mounted in /mnt/ubi2/
> My main application is in /mnt/ubi1/ and is running.
>  
> How could I update the actual ubifs ubi0_0, ubi1_0 and ubi2_0 ?
>  
> I tried ist with 
> 1.) flash_eraseall
> 2.) nandwrite
> ---> This doesn´t work -> after restart I got errors -> RFS is damaged
> and doesn´t boot anymore
>  
> another try:
> 1.) ubiupdatevol
> -----> the problem - this program doesn´t work if the ubifs is mounted
> - but I can´t unmount /mnt/ubi1 or /mnt/ubi2 or the RFS because there
> are applications running.

I'm not sure what exactly you ask, but you cannot update UBIFS
file system while it is mounted. You have to unmount it first.
Does any file-system allows this at all?

Or I misunderstood your questions?

-- 
Best regards,
Artem Bityutskiy (Битюцкий Артём)

Re: How to update UBIFS while running an application ?

[Ricard Wanderlof]

On Sat, 4 Apr 2009, Artem Bityutskiy wrote:

>I'm not sure what exactly you ask, but you cannot update UBIFS file 
> system while it is mounted. You have to unmount it first. Does any 
> file-system allows this at all?

While not entirely koscher, one way around the problem of upgrading a 
system with a root file system is flash based, is to get the application 
into memory (possibly lock down the pages), rewrite the root file system 
without unmounting it, then rebooting immediately after.

I don't know if this would work with UBIFS, but given the right 
circumstances it works fine with JFFS2.

/Ricard
--
Ricard Wolf Wanderlöf                           ricardw(at)axis.com
Axis Communications AB, Lund, Sweden            www.axis.com
Phone +46 46 272 2016                           Fax +46 46 13 61 30