From: "H. Peter Anvin" <hpa@zytor.com>
To: "linux-btrfs@vger.kernel.org" <linux-btrfs@vger.kernel.org>
Cc: Chris Mason <clm@fb.com>
Subject: Re: Formalizing the use of Boot Area B
Date: Tue, 20 May 2014 16:29:15 -0700 [thread overview]
Message-ID: <537BE54B.3060603@zytor.com> (raw)
In-Reply-To: <537403E3.6090902@zytor.com>
On 05/14/2014 05:01 PM, H. Peter Anvin wrote:
> It turns out that the primary 64K "Boot Area A" is too small for some
> applications and/or some architectures.
>
> When I discussed this with Chris Mason, he pointed out that the area
> beyond the superblock is also unused, up until at least the megabyte
> point (from my reading of the mkfs code, it is actually slightly more
> than a megabyte.)
>
> This is present in all versions of mkfs.btrfs that has the superblock at
> 64K (some very early ones had the superblock at 16K, but that format is
> no longer supported), so all that is needed is formalizing the specs as
> to the use of this area.
>
> My suggestion is that 64-128K is reserved for extension of the
> superblock and/or any other filesystem uses, and 128-1024K is defined as
> Boot Area B. However, if there may be reason to reserve more, then we
> should do that. Hence requesting a formal decision as to the extent and
> ownership of this area.
>
> -hpa
>
Ping on this? If I don't hear back on this I will probably just go
ahead and use 128K-1024K.
-hpa
next prev parent reply other threads:[~2014-05-20 23:29 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2014-05-15 0:01 Formalizing the use of Boot Area B H. Peter Anvin
2014-05-20 23:29 ` H. Peter Anvin [this message]
2014-05-20 23:37 ` Chris Mason
2014-05-20 23:39 ` H. Peter Anvin
2014-05-21 0:04 ` H. Peter Anvin
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