Re: [PATCH] Install nfsv4-related drivers when users specify nfs dumping via dracut_args

[Philipp Rudo]

Hi Coiby,

On Tue, 27 Dec 2022 09:26:23 +0800
Coiby Xu  wrote:
> Resolves: https://bugzilla.redhat.com/show_bug.cgi?id=2140721
>
> Currently, if users specify dumping to nfsv4 target via
>   dracut_args --mount "<NFS-server-ip>:/var/crash /mnt nfs defaults"
> it fails with the following errors,
>     [    5.159760] mount[446]: mount.nfs: Protocol not supported
>     [    5.164502] systemd[1]: mnt.mount: Mount process exited, code=exited, status=32/n/a
>     [    5.167616] systemd[1]: mnt.mount: Failed with result 'exit-code'.
>     [FAILED] Failed to mount /mnt.
>
> This is because nfsv4-releted drivers are not installed to kdump initrd.
> mkdumprd calls dracut with "--hostonly-mode strict". If nfsv4-related
> drivers aren't loaded before calling dracut, they won't be installed.
> When users specify nfs dumping via dracut_args, kexec-tools won't mount
> the nfs fs beforehand hence nfsv4-related drivers won't be installed.
> Note dracut only installs the nfs driver i.e. nfsv3 driver for "--mount
> ... nfs". So also install nfsv4-related drivers when users specify nfs
> dumping via dracut_args. Since nfs_layout_nfsv41_files depends on nfsv4,
> the nfsv4 driver will be installed automatically.
>
> As for the reason why we support nfs dumping via dracut_args instead of
> asking user to use the nfs directive, please refer to commit 74c6f464
> ("Support special mount information via 'dracut_args'").

I don't understand why this was designed the way it is. Personally I
would have treated the dracut_args and nfs directive identical and
would simply have added a "--no-mount" option...
Anyway that's nothing we can change right now. So your patch looks like
a valid workaround to me.

Thanks
Philipp
> Fixes: 4eedcae5 ("dracut-module-setup.sh: don't include multipath-hostonly")
> Reported-by: [e-mail]
> Signed-off-by: Coiby Xu
>
> mkdumprd | 9 +++++++++
>  1 file changed, 9 insertions(+)
>
> diff --git a/mkdumprd b/mkdumprd
> index 3e250e02..51ca4f01 100644
> --- a/mkdumprd
> +++ b/mkdumprd
> @@ -420,6 +420,15 @@ while read -r config_opt config_val; do
>    	verify_core_collector "$config_val"
>    	;;
>    dracut_args)
> # When users specify nfs dumping via dracut_args, kexec-tools won't
> # mount nfs fs beforehand thus nfsv4-related drivers won't be installed
> # because we call dracut with --hostonly-mode strict. So manually install
> # nfsv4-related drivers.
> if [[ $(get_dracut_args_fstype "$config_val") == nfs* ]]; then
> 	add_dracut_arg "--add-drivers" nfs_layout_nfsv41_files
> fi
> while read -r dracut_arg; do
>   	add_dracut_arg "$dracut_arg"
>   done <<< "$(echo "$config_val" | xargs -n 1 echo)"