On Wed, 2018-01-31 at 13:32 -0600, Rob Landley wrote:
> On 01/30/2018 03:46 PM, Mimi Zohar wrote:
> > Commit 16203a7a9422 ("initmpfs: make rootfs use tmpfs when CONFIG_TMPFS
> > enabled") introduced using tmpfs as the rootfs filesystem. The use of
> > tmpfs is limited to systems that do not specify "root=" on the boot
> > command line.
> >
> > Without the check "!saved_root_name[0]", rootfs uses tmpfs. As there
> > must be a valid reason for this check, this patch introduces a new boot
> > command line option named "noramfs" to force rootfs to use tmpfs.
> >
> > Signed-off-by: Mimi Zohar <zohar@xxxxxxxxxxxxxxxxxx>
>
> How about just:
>
> diff --git a/init/do_mounts.c b/init/do_mounts.c
> index 7cf4f6d..af66ede 100644
> --- a/init/do_mounts.c
> +++ b/init/do_mounts.c
> @@ -632,8 +632,8 @@ int __init init_rootfs(void)
> if (err)
> return err;
>
> - if (IS_ENABLED(CONFIG_TMPFS) && !saved_root_name[0] &&
> - (!root_fs_names || strstr(root_fs_names, "tmpfs"))) {
> + if (IS_ENABLED(CONFIG_TMPFS) && (!saved_root_name[0] ||
> + !strcmp(saved_root_name, "tmpfs"))) {
> err = shmem_init();
> is_tmpfs = true;
> } else {
>
> (Obviously-signed-off-by: Rob Landley <rob@xxxxxxxxxxx>)
>
> I.E. if you somehow just can't stop yourself from specifying root= when
> using rootfs, have "root=tmpfs" do what you want.
I tried overloading "rootfstype=tmpfs", before posting this work
around, but for some reason that just doesn't work.
>
> (The old "I configured in tmpfs and am using rootfs but I want that rootfs
> to be ramfs, not tmpfs" code doesn't seem to be a real-world concern, does
> it?)
I must be missing something. Which systems don't specify "root=" on
the boot command line. If we want to include and restore xattrs,
there needs to be a way of using tmpfs.
Mimi
>
> > ---
> > Documentation/admin-guide/kernel-parameters.txt | 2 ++
> > init/do_mounts.c | 15 +++++++++++++--
> > 2 files changed, 15 insertions(+), 2 deletions(-)
>
> I suppose I should do a documentation update too. Lemme send a proper one
> after work...
>
> Rob
>
> P.S. While I'm at it, I've meant to wire up rootflags= so you can specify
> a memory limit other than 50% forever, I should do that too. And resend
> my "make DEVTMPFS_MOUNT apply to initramfs" patch (with the debian bug
> workaround)...
>
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