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From: Richard Weinberger <richard@nod.at>
To: hujianyang <hujianyang@huawei.com>
Cc: dedekind1@gmail.com, dwmw2@infradead.org,
	computersforpeace@gmail.com, linux-mtd@lists.infradead.org,
	linux-kernel@vger.kernel.org
Subject: Re: [PATCH] UBI: vtbl: Use ubi_eba_atomic_leb_change()
Date: Fri, 31 Oct 2014 11:57:38 +0100	[thread overview]
Message-ID: <54536B22.4000807@nod.at> (raw)
In-Reply-To: <54536834.1020005@huawei.com>

Am 31.10.2014 um 11:45 schrieb hujianyang:
> This question is basing on your comment for this patch:
> 
> """
> we can guarantee that the first VTBL record is always
> correct and we don't really need the second one anymore.
> """
> 
> I think that means one PEB is enough in your considering.
> So I want to know if you are sure about this. Because
> we use two leb for master_node in ubifs-level. So maybe
> VTBL is like super_node, not master_node, right?

Yes, technically one PEB is enough if atomic leb change is used.
But existing UBI implementations want a second one
and a backup VTBL PEB is good for robustness.
i.e. if the PEB turns bad we have a backup and do not lose
all volume meta information.

Thanks,
//richard

      reply	other threads:[~2014-10-31 10:57 UTC|newest]

Thread overview: 6+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2014-10-25 17:43 [PATCH] UBI: vtbl: Use ubi_eba_atomic_leb_change() Richard Weinberger
2014-10-30  8:55 ` Artem Bityutskiy
2014-10-31  4:03   ` hujianyang
2014-10-31  8:09     ` Richard Weinberger
2014-10-31 10:45       ` hujianyang
2014-10-31 10:57         ` Richard Weinberger [this message]

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