Re: [RFC v4] UBI: Fastmap support (aka checkpointing)

From: Richard Weinberger
Date: Tue May 15 2012 - 14:10:24 EST


Hi Subodh,

Am 15.05.2012 19:48, schrieb Subodh Nijsure:
Hello Richard,

On 05/15/2012 10:11 AM, Richard Weinberger wrote:
v1: https://lwn.net/Articles/481612/
v2: https://lwn.net/Articles/496586/
v3: Didn't release it to linux-mtd
Will kernel that has older UBI drivers be able to mount and update the
UBI volumes that have been created with checkpointing feature?

Of course!

Say I have bootrom that has 3.0.X kernel that has no knowledge of UBI
checkpointing, and my flash /dev/mtd2 has UBI volume with checkpointing
enabled. Will this bootrom be able to attach /dev/mtd2 and mount UBI
volume and read/write files on it?

Sure!
Your bootrom will scan the UBI volume and detect two unknown internal
volumes with compat=delete in their volume headers.
So, it will delete the two fastmap volumes and continue scanning.
It can alter the volume and so on.

Thanks,
//richard

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