"add only" fs

"add only" fs

[Fabrizio Pollastri]

Hello,

a common problem in embedded systems is to log important data in a way
safe against power failure and software bugs.
The question is: may be jffs2 the right place to introduce an "add only"
protection? It can be at partition level, in such a way that mounting
that
partition as "add only" I am protected against loss of data, because I
can only create new files and/or append data to existing files and never
delete or truncate a file unless the partition is remounted rw.


Best regards,
Fabrizio Pollastri.

Re: "add only" fs

[David Woodhouse]

pollastri@iriti.cnr.it said:
> a common problem in embedded systems is to log important data in a way
> safe against power failure and software bugs. The question is: may be
> jffs2 the right place to introduce an "add only" protection? It can be
> at partition level, in such a way that mounting that partition as "add
> only" I am protected against loss of data, because I can only create
> new files and/or append data to existing files and never delete or
> truncate a file unless the partition is remounted rw. 

JFFS2 _has_ to move data around, even data which haven't changed. If you 
want 100% guarantees (or as close as possible) that some parts can't 
change, put them in a separate partition which you mount readonly.

--
dwmw2