Re: [PATCH] nfs-server-generator: handle 'noauto' mounts correctly.

[ChunYu Wang <chunwang@redhat.com>]

Hi, Neil,

Thanks for your patch! But seems there still exists same problem on my
fedora 25 with a patched nfs-utils version, am I made something wrong
or we just need more patches for fedora family..?

-- I just try it with most simple steps:
[root@bootp-73-5-219 ~]# cat /etc/fstab |grep boot
UUID=932047db-24e7-4043-8373-6e87333b9ce1 /boot                   ext4
   noauto        1 2
^^ Set flag to 'noauto'

[root@bootp-73-5-219 ~]# umount /boot; mount -a; mountpoint /boot
/boot is not a mountpoint
^^ umount ready

[root@bootp-73-5-219 ~]# cat /lib/systemd/system/nfs-server.service |grep boot
RequiresMountsFor= /boot

[root@bootp-73-5-219 ~]# systemctl restart nfs-server

[root@bootp-73-5-219 ~]# mountpoint /boot/
/boot/ is a mountpoint
[root@bootp-73-5-219 ~]# mount |grep boot
/dev/sda1 on /boot type ext4 (rw,relatime,seclabel,data=ordered)
^^ mount again automatically
--

-- Already patched:
[root@bootp-73-5-219 ~]# rpm -q nfs-utils
nfs-utils-2.1.1-2.rc1.fc25.x86_64
[root@bootp-73-5-219 nfs-utils]# grep nfs-server-generator -r ./*.patch
./nfs-utils-2.1.2-rc1.patch:diff --git
a/systemd/nfs-server-generator.c b/systemd/nfs-server-generator.c
...
[root@bootp-73-5-219 nfs-utils]# cat ./nfs-utils.spec |grep -i patch001
Patch001: nfs-utils-2.1.2-rc1.patch
%patch001 -p1
--

Thanks,
ChunYu Wang





On Wed, Feb 8, 2017 at 10:03 AM, NeilBrown <neilb@suse.com> wrote:
>
> When this code was written, the systemd documentation stated
> that "RequiresMountsFor" ignored mountpoints marked as "noauto".
> Unfortunately this is incorrect.  Consquently a filesystem marked
> as noauto that is also NFS exported will currently be mounted when
> the NFS server is started. This is not what people expect.
>
> So add a check for the noauto flag.  If any ancestor of a given
> export point has the noauto flag, no RequiresMountsFor will be
> generated for that point.
>
> Also skip RequiresMountsFor for exports marked 'mountpoint', as their
> absence is, theoretically, already handled by mountd.
>
> URL: https://github.com/systemd/systemd/issues/5249
> Signed-off-by: NeilBrown <neilb@suse.com>
> ---
>  systemd/nfs-server-generator.c | 26 ++++++++++++++++++++++++++
>  1 file changed, 26 insertions(+)
>
> diff --git a/systemd/nfs-server-generator.c b/systemd/nfs-server-generator.c
> index cc99969e9922..4aa65094ca07 100644
> --- a/systemd/nfs-server-generator.c
> +++ b/systemd/nfs-server-generator.c
> @@ -84,6 +84,28 @@ static void systemd_escape(FILE *f, char *path)
>         }
>  }
>
> +static int has_noauto_flag(char *path)
> +{
> +       FILE            *fstab;
> +       struct mntent   *mnt;
> +
> +       fstab = setmntent("/etc/fstab", "r");
> +       if (!fstab)
> +               return 0;
> +
> +       while ((mnt = getmntent(fstab)) != NULL) {
> +               int l = strlen(mnt->mnt_dir);
> +               if (strncmp(mnt->mnt_dir, path, l) != 0)
> +                       continue;
> +               if (path[l] && path[l] != '/')
> +                       continue;
> +               if (hasmntopt(mnt, "noauto"))
> +                       break;
> +       }
> +       fclose(fstab);
> +       return mnt != NULL;
> +}
> +
>  int main(int argc, char *argv[])
>  {
>         char            *path;
> @@ -124,6 +146,10 @@ int main(int argc, char *argv[])
>                 for (exp = exportlist[i].p_head; exp; exp = exp->m_next) {
>                         if (!is_unique(&list, exp->m_export.e_path))
>                                 continue;
> +                       if (exp->m_export.e_mountpoint)
> +                               continue;
> +                       if (has_noauto_flag(exp->m_export.e_path))
> +                               continue;
>                         if (strchr(exp->m_export.e_path, ' '))
>                                 fprintf(f, "RequiresMountsFor=\"%s\"\n",
>                                         exp->m_export.e_path);
> --
> 2.11.0
>