[systemd-devel] [PATCH] fstab-generator: introduce rd.weak_sysroot to bypass failures in sysroot.mount

[Vivek Goyal]

On Tue, Jul 30, 2013 at 07:53:11PM +0800, WANG Chao wrote:
> If specified kernel command line rd.weak_sysroot, fstab-generate will
> generate a weaker version of sysroot.mount:
>  - It's not required by initrd-root-fs.target.
>  - It's not before initrd-root-fs.target.
> 
> So that failure in the weaker sysroot.mount will not fail
> initrd-root-fs.target. And systemd will try continue rather than
> entering isolated emergency mode.
> 
> Signed-off-by: WANG Chao <chaowang at redhat.com>

Chao, so why rd.action_on_fail=continue is not sufficient here? So if
mounting root fails, and if rd.action_on_fail=continue, then systemd
should just continue.

Or it will be considered an initramfs parameter and we need to come
up with a new one for systemd?

Or may be if rd.action_on_fail is set, it automtically does some
action which conveys to systemd to continue after failures.

Thanks
Vivek

> ---
>  man/kernel-command-line.xml           | 10 ++++++++++
>  man/systemd-fstab-generator.xml       | 10 ++++++++++
>  src/fstab-generator/fstab-generator.c |  5 ++++-
>  3 files changed, 24 insertions(+), 1 deletion(-)
> 
> diff --git a/man/kernel-command-line.xml b/man/kernel-command-line.xml
> index a4b7d13..0c2e97d 100644
> --- a/man/kernel-command-line.xml
> +++ b/man/kernel-command-line.xml
> @@ -274,6 +274,16 @@
>                          </varlistentry>
>  
>                          <varlistentry>
> +                                <term><varname>rd.weak_sysroot</varname></term>
> +
> +                                <listitem>
> +                                        <para>Configures the sysroot.mount
> +                                        logic in initrd. For details, see
> +                                        <citerefentry><refentrytitle>systemd-fstab-generator</refentrytitle><manvolnum>8</manvolnum></citerefentry>.</para>
> +                                </listitem>
> +                        </varlistentry>
> +
> +                        <varlistentry>
>                                  <term><varname>modules-load=</varname></term>
>                                  <term><varname>rd.modules-load=</varname></term>
>  
> diff --git a/man/systemd-fstab-generator.xml b/man/systemd-fstab-generator.xml
> index 4bd25bf..de0ed2f 100644
> --- a/man/systemd-fstab-generator.xml
> +++ b/man/systemd-fstab-generator.xml
> @@ -101,6 +101,16 @@
>                                  the initrd.  </para></listitem>
>                          </varlistentry>
>  
> +                        <varlistentry>
> +                                <term><varname>rd.weak_sysroot</varname></term>
> +
> +                                <listitem><para>If specified, systemd will
> +                                ingore failures in sysroot.mount and try to
> +                                continue rather than enter emergency mode.
> +                                It is honored only by initial RAM disk
> +                                (initrd). </para></listitem>
> +                        </varlistentry>
> +
>                  </variablelist>
>          </refsect1>
>  
> diff --git a/src/fstab-generator/fstab-generator.c b/src/fstab-generator/fstab-generator.c
> index c17299f..449e725 100644
> --- a/src/fstab-generator/fstab-generator.c
> +++ b/src/fstab-generator/fstab-generator.c
> @@ -492,6 +492,7 @@ static int parse_new_root_from_proc_cmdline(void) {
>          char *w, *state;
>          int r;
>          size_t l;
> +        bool weak = false;
>  
>          r = read_one_line_file("/proc/cmdline", &line);
>          if (r < 0) {
> @@ -544,6 +545,8 @@ static int parse_new_root_from_proc_cmdline(void) {
>  
>                          free(opts);
>                          opts = o;
> +                } else if (streq(word, "rd.weak_sysroot")) {
> +                        weak=true;
>                  }
>          }
>  
> @@ -558,7 +561,7 @@ static int parse_new_root_from_proc_cmdline(void) {
>          }
>  
>          log_debug("Found entry what=%s where=/sysroot type=%s", what, type);
> -        r = add_mount(what, "/sysroot", type, opts, 0, false, false, false,
> +        r = add_mount(what, "/sysroot", type, opts, 0, false, weak, false,
>                        false, NULL, NULL, NULL, SPECIAL_INITRD_ROOT_FS_TARGET, "/proc/cmdline");
>  
>          return (r < 0) ? r : 0;
> -- 
> 1.8.3.1