Re: [PATCH 0/5] initmpfs v2: use tmpfs instead of ramfs for rootfs

[Hugh Dickins <hughd@google.com>]

On Wed, 17 Jul 2013, Andrew Morton wrote:
> 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.

I'll leave others to comment on "mount --bind", but with regard to "df":
yes, we could enhance ramfs with accounting such as tmpfs has, to allow
it to support non-0 "df".  We could have done so years ago; but have
always preferred to leave ramfs as minimal, than import tmpfs features
into it one by one.

I prefer Rob's approach of making tmpfs usable for rootfs.

Hugh

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