Detach the ubi device of rootfs

Detach the ubi device of rootfs

[Rock Lee]

Hi,
I am studying the process of reboot in linux, but did find any script
in /etc to detach ubi device for rootfs. If I reboot the system when
ubi device of rootfs is scrubing, is it a risk for flash ?

-- 
Cheers,
Rock

Re: Detach the ubi device of rootfs

[Richard Weinberger]

Rock,

On Mon, Oct 9, 2017 at 1:11 PM, Rock Lee <rockdotlee@gmail.com> wrote:
> Hi,
> I am studying the process of reboot in linux, but did find any script
> in /etc to detach ubi device for rootfs. If I reboot the system when
> ubi device of rootfs is scrubing, is it a risk for flash ?

Why do you think you need to detach upon reboot?
UBI and UBIFS are designed to face power-cuts at any time.
Although, sane setups with initramfs/systemd unmount also the rootfs
upon reboot.

-- 
Thanks,
//richard

Re: Detach the ubi device of rootfs

[Rock Lee]

> Why do you think you need to detach upon reboot?
> UBI and UBIFS are designed to face power-cuts at any time.
> Although, sane setups with initramfs/systemd unmount also the rootfs
> upon reboot.
>

When reboot, UBIFS will be remount as read-only, from the filesystem
part, it is safe, because there is no data write to it.  I see ubi
background thread will exit when ubi detach, and there would no
scrubing anymore, I am sure reboot after detach is safe enough in UBI
layer. I am just curious what will happen when reboot the system while
ubi is scrubing. Will it damage the flash if this situation happens a
lot?

Thanks
-- 
Cheers,
Rock

Re: Detach the ubi device of rootfs

[Richard Weinberger]

Am Dienstag, 10. Oktober 2017, 04:02:09 CEST schrieb Rock Lee:
> > Why do you think you need to detach upon reboot?
> > UBI and UBIFS are designed to face power-cuts at any time.
> > Although, sane setups with initramfs/systemd unmount also the rootfs
> > upon reboot.
> 
> When reboot, UBIFS will be remount as read-only, from the filesystem
> part, it is safe, because there is no data write to it.  I see ubi
> background thread will exit when ubi detach, and there would no
> scrubing anymore, I am sure reboot after detach is safe enough in UBI
> layer. I am just curious what will happen when reboot the system while
> ubi is scrubing. Will it damage the flash if this situation happens a
> lot?

Scrubbing is an atomic operation, just like copying a LEB.
What problem do you have in mind?

Thanks,
//richard

-- 
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Re: Detach the ubi device of rootfs

[Rock Lee]

> Scrubbing is an atomic operation, just like copying a LEB.
> What problem do you have in mind?
>
Since scrubbing is an atomic operation, I have nothing to worry about :-)

Thanks
-- 
Cheers,
Rock