On Mon, May 11, 2020 at 9:43 PM piliu <piliu(a)redhat.com> wrote:
On 05/11/2020 02:42 PM, Kairui Song wrote:
> By this point, there is still an unresolved vfs kernel issue that blocks
> systemd from mounting the dump target properly from time to time. To
> prevent systemd from failing by mounting the dump target, we can add
> nofail option to the kdump mount point.
>
> But adding nofail will wipe out default dependency of the mount point,
> see commit 94a7b43, so systemd randomize the order of calling kdump.sh
> and mounting the dump target and lead to unexpected behavior.
> However we can use x-systemd.before to ensure the mount is done
> in right order.
>
> With both nofail and x-systemd.before=kdump-capture.service, systemd
> will try to mount the dump target before calling kdump, and even if the
> mount failed, kdump.sh still be called and try to mount again. See
> dump_fs function, which will try to mount if the target is not mounted.
> Kdump will only fail if both mount attemp fails.
I had thought about the asymmetry after the previous partial revert
patch, and its value. And this patch resolves it!
>
> Else if the kdump target mount failed or unstable, systemd will directly
> jump to kdump failure action, and kdump fails.
>
> This should improve the robustness in general with no other risk.
> ---
> mkdumprd | 3 +++
> 1 file changed, 3 insertions(+)
>
> diff --git a/mkdumprd b/mkdumprd
> index cedf536..26e71ba 100644
> --- a/mkdumprd
> +++ b/mkdumprd
> @@ -83,6 +83,9 @@ to_mount() {
> # drop nofail or nobootwait
> _options=$(echo $_options | sed 's/\(^\|,\)nofail\($\|,\)/\1/g')
> _options=$(echo $_options | sed 's/\(^\|,\)nobootwait\($\|,\)/\1/g')
> + # use both nofail and x-systemd.before to ensure systemd will try best to
> + # mount it before kdump starts, this is an attempt to improve robustness
> + _options="$_options,nofail,x-systemd.before=kdump-capture.service"
>
> _mntopts="$_target $_fstype $_options"
> #for non-nfs _dev converting to use udev persistent name
>
Acked-by: Pingfan Liu <piliu(a)redhat.com>
Hi Pingfan, thank you very much for the review, however I found there
are still a timing issue with this patch, I've send V2, could you help
have a look?
--
Best Regards,
Kairui Song