Re: [PATCH] use tmpfs for rootfs v3

["Mike Frysinger" <vapier.adi@gmail.com>]

On Mon, Oct 20, 2008 at 14:13, Bodo Eggert wrote:
> On Sun, 19 Oct 2008, Mike Frysinger wrote:
>> On Fri, Oct 17, 2008 at 07:16, Bodo Eggert wrote:
>> > --- linux-2.6.27.2-numlock/fs/Kconfig   2008-10-10 13:18:34.000000000 +0200
>> > +++ linux-2.6.27.3-tmpfs/fs/Kconfig     2008-10-11 15:42:21.000000000 +0200
>> > @@ -953,6 +953,27 @@ config TMPFS_POSIX_ACL
>> >
>> >          If you don't know what Access Control Lists are, say N.
>> >
>> > +config TMPFS_ROOT
>> > +       bool "Use tmpfs instrad of ramfs for initramfs"
>> > +       depends on TMPFS && SHMEM
>> > +       default n
>> > +       help
>> > +         This replaces the ramfs used for unpacking the cpio images
>> > +         with tmpfs.
>> > +
>> > +         If unsure, say N
>>
>> this should be init/Kconfig and depend on BLK_DEV_INITRD i think.  and
>> then update the comment to talk about the initial filesystem rather
>> than cpio images.
>
> Maybe, but then you'd have to go to filesystems->pseudo-fs to enable tmpfs,
> then to i-don't-remember to set it as the rootfs, and then back to
> fs->pseudo-fs to unselect ramfs.
>
> Thinking of it as a tmpfs option makes it much easier to use.

i guess that works

>> > +config RAMFS
>> > +       bool "Ramfs file system support" if TMPFS_ROOT
>>
>> if you have initramfs support disabled, then you should be able to
>> disable RAMFS as well.  so perhaps the depend should read like:
>> if BLK_DEV_INITRD && TMPFS_ROOT || !BLK_DEV_INITRD
>
> No, since a kernel not having initcpio support will mount rootfs anyway,

we should get that fixed then

> create some directories and special files and use them to open the console
> and to mount the real root into.

erm, i dont recall seeing any init code create any directories or
files.  opening /dev/console doesnt require the fake rootfs, nor does
mounting the real root on top of it.  where exactly do you see this
logic ?
-mike