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Date:   Tue, 31 Oct 2023 13:33:22 -0700
From:   "H. Peter Anvin" <hpa@zytor.com>
To:     Stefan Berger <stefanb@linux.ibm.com>,
        Greg Kroah-Hartman <gregkh@linuxfoundation.org>
CC:     linux-kernel@vger.kernel.org,
        "Milton D. Miller II" <mdmii@outlook.com>,
        Rob Landley <rob@landley.net>,
        Jeff Layton <jlayton@kernel.org>, Jens Axboe <axboe@kernel.dk>,
        Jim Cromie <jim.cromie@gmail.com>,
        Sam Ravnborg <sam@ravnborg.org>,
        "Eric W. Biederman" <ebiederm@xmission.com>,
        Alexander Viro <viro@zeniv.linux.org.uk>,
        Mimi Zohar <zohar@linux.ibm.com>
Subject: Re: [RFC PATCH] rootfs: Use tmpfs for rootfs even if root= is given
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References: <20231031154417.621742-1-stefanb@linux.ibm.com> <2023103159-punctuate-amount-f09d@gregkh> <b035a00f-865a-453c-bb27-0916aada0594@linux.ibm.com>
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On October 31, 2023 10:11:01 AM PDT, Stefan Berger <stefanb@linux=2Eibm=2Ec=
om> wrote:
>
>On 10/31/23 12:56, Greg Kroah-Hartman wrote:
>> On Tue, Oct 31, 2023 at 11:44:17AM -0400, Stefan Berger wrote:
>>> rootfs currently does not use tmpfs if the root=3D boot option is pass=
ed
>>> even though the documentation about rootfs (added in 6e19eded3684) in
>>> Documentation/filesystems/ramfs-rootfs-initramfs=2Erst states:
>>>=20
>>>    If CONFIG_TMPFS is enabled, rootfs will use tmpfs instead of ramfs =
by
>>>    default=2E  To force ramfs, add "rootfstype=3Dramfs" to the kernel =
command
>>>    line=2E
>> At this point in time, is there even any difference between ramfs and
>> tmpfs anymore?  Why would you want to choose one over the other here?
>
>CONFIG_TPMFS_XATTRS allows us to set xattrs, such as security=2Eima=2E
>
>=C2=A0=C2=A0 Stefan
>
>>=20
>> thanks,
>>=20
>> greg k-h
Why do we even keep ramfs as a standalone file system? To guarantee it can=
not be swapped out? Does anyone actually use it?