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Date: Wed, 17 Jul 2013 16:06:02 -0700
From: Andrew Morton <akpm@linux-foundation.org>
To: Rob Landley <rob@landley.net>
Cc: linux-kernel@vger.kernel.org, Alexander Viro <viro@zeniv.linux.org.uk>,
        "Eric W. Biederman" <ebiederm@xmission.com>,
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        linux-fsdevel@vger.kernel.org, linux-mm@kvack.org,
        Rusty Russell <rusty@rustcorp.com.au>, Sam Ravnborg <sam@ravnborg.org>,
        Stephen Warren <swarren@nvidia.com>
Subject: Re: [PATCH 0/5] initmpfs v2: use tmpfs instead of ramfs for rootfs
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On Tue, 16 Jul 2013 08:31:13 -0700 (PDT) Rob Landley <rob@landley.net> wrote:

> Use tmpfs for rootfs when CONFIG_TMPFS=y and there's no root=.
> Specify rootfstype=ramfs to get the old initramfs behavior.
> 
> The previous initramfs code provided a fairly crappy root filesystem:
> didn't let you --bind mount directories out of it, reported zero
> size/usage so it didn't show up in "df" and couldn't run things like
> rpm that query available space before proceeding, would fill up all
> available memory and panic the system if you wrote too much to it...

The df problem and the mount --bind thing are ramfs issues, are they
not?  Can we fix them?  If so, that's a less intrusive change, and we
also get a fixed ramfs.

> Using tmpfs instead provides a much better root filesystem.
> 
> Changes from last time: use test_and_set_bit() for "once" logic.