Re: [Yaffs] Re : Partition size and mounting time

On Saturday 06 February 2010 03:58:27 Dunge wrote:
> Sorry James, wrong reply destination.
>
> Well thx for all three quick answers! I'll answer your question to clear
> things up:
>
> Peter
> Barada: Unfortunately, our device NEEDS to be shutdown at any time, or
> else we would simply had kept a sdcard ext3 filesystem. This is an
> handheld device used by construction road workers outside and they need
> to switch power source often. Also used by power source from cars, so I
> can't send a "shutdown" every time the user turn the key.

How much residual power does the device have?

You should not need to do a full shutdown. A sync should be enough so long as
you don't go and write to the fs again immediately.

>
> Charles
> Manning and James Kehl: Thanks for the information. We currently used
> Debian-arm-etch (4.0) with kernel 2.6.21 so I probably don't have the
> yaffs2 fix. I tried to install Debian Lenny armel eabi (5.0), but it
> had troubles with drivers and such. Still, our version have sync
> command, which I didn't know how to use until I read your message.
> Problem is, even with a small test application who don't write at all,
> it get invalidated. Is it the OS who does the writing. I just noticed I
> can mount with a "-o sync" option, but it don't seems to work. I tried
> calling sync manually before power down, no help. I tried "reboot" and
> "shutdown now", it still takes 25sec to mount after. BUT, if I manually
> umount the block, power off and on, it takes about 5sec instead, which
> would be nice.

Add +os to the tracing to see what is happening.

>
> As
> for repartitionning, I was asking if it's a good idea and how to do it.
> From what I understand, YAFFS2 always takes the full amount of the
> mtdblock, and the size of the block is determinated when loading the
> nand driver, which I can't really modify. I guess this is a question I
> should ask on my board mailing list instead of here.

The partitioning is normally done at the board level so that's probably a good
idea.
>
> What about ubifs? Would it be a better alternative in my current situation?

Try it. I've used ubifs in one project and was very frustrated by how it could
clobber files if power fails before a sync. That was 6 months ago and I don't
know it is it any better now.