[ECOS] Re: RE : RE : [ECOS] Is JFFS2 thread-safe?

David Woodhouse dwmw2@infradead.org
Thu Nov 27 10:24:00 GMT 2003

On Thu, 2003-11-27 at 11:03 +0100, Vincent Catros wrote:
> Thanks David,
> This is clear for me now.


In answer to your earlier question about chmod/chown -- they're trivial
to implement. JFFS2 needs to keep track of modes and ownership
internally (in its struct _inode) so that it doesn't corrupt them when
modifying a file system shared with Linux. They should already be
returned by stat(), and the only barrier to allowing you to _change_
modes or ownership from your application is the lack of suitable API for
such purpose. I don't really want to abuse jffs2_setinfo().

The TODO list for JFFS2/eCos is now as follows. I'm hoping someone with
more eCos-clue will pick up some of this:

 - Fill in the skeleton gcthread.c so it actually does something.

 - Check and possibly fix locking of icache mangling in fs-ecos.c

 - Check that os-ecos.h defines 'spin_lock()' to something appropriate.

 - Fix unmount of root file system after chdir().

 - Fix atomicity of renames. Why was the unlink added before rename?

 - Further cleanup -- should the functions in dir-ecos.c take 'struct
   dirsearch' instead of various components thereof, or should each of
   those functions just be moved inside its only caller in fs-ecos.c?

 - Improve mount time by using pointer directly into flash chip instead
   of jffs2_flash_read() for the initial scan -- look at the #ifdef
   __ECOS bit in scan.c for details.

 - Reduce memory usage. There are fields marked for possible removal in
   struct _inode, and there's the __totlen field in struct
   jffs2_raw_node_ref as discussed recently.

Sort of separate, and I have a hacked-up mostly working version already:

 - Make fileio package not gratuitously include kernel header files.

 - Add up RedBoot fileio support so RedBoot can read/write JFFS2.


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