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From:   Olga Kornievskaia <olga.kornievskaia@gmail.com>
Date:   Wed, 23 Feb 2022 18:55:20 -0500
Message-ID: <CAN-5tyHy_+tBfv3PuD0CBwHbppHo3pRNwo0O9xRGjZxK0-rOjw@mail.gmail.com>
Subject: Re: [PATCH v1] NFSv4.1 provide mount option to toggle trunking discovery
To:     Trond Myklebust <trond.myklebust@hammerspace.com>,
        Anna Schumaker <anna.schumaker@netapp.com>,
        Kurt Garloff <kurt@garloff.de>
Cc:     linux-nfs <linux-nfs@vger.kernel.org>
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I have forgotten to cc Kurt Garloff to the post.

On Wed, Feb 23, 2022 at 12:40 PM Olga Kornievskaia
<olga.kornievskaia@gmail.com> wrote:
>
> From: Olga Kornievskaia <kolga@netapp.com>
>
> Introduce a new mount option -- trunkdiscovery,notrunkdiscovery -- to
> toggle whether or not the client will engage in actively discovery
> of trunking locations.
>
> Signed-off-by: Olga Kornievskaia <kolga@netapp.com>
> ---
>  fs/nfs/client.c           | 3 ++-
>  fs/nfs/fs_context.c       | 8 ++++++++
>  include/linux/nfs_fs_sb.h | 1 +
>  3 files changed, 11 insertions(+), 1 deletion(-)
>
> diff --git a/fs/nfs/client.c b/fs/nfs/client.c
> index d1f34229e11a..84c080ddfd01 100644
> --- a/fs/nfs/client.c
> +++ b/fs/nfs/client.c
> @@ -857,7 +857,8 @@ static int nfs_probe_fsinfo(struct nfs_server *server, struct nfs_fh *mntfh, str
>         }
>
>         if (clp->rpc_ops->discover_trunking != NULL &&
> -                       (server->caps & NFS_CAP_FS_LOCATIONS)) {
> +                       (server->caps & NFS_CAP_FS_LOCATIONS &&
> +                        !(server->flags & NFS_MOUNT_NOTRUNK_DISCOVERY))) {
>                 error = clp->rpc_ops->discover_trunking(server, mntfh);
>                 if (error < 0)
>                         return error;
> diff --git a/fs/nfs/fs_context.c b/fs/nfs/fs_context.c
> index ea17fa1f31ec..ad1448a63aa0 100644
> --- a/fs/nfs/fs_context.c
> +++ b/fs/nfs/fs_context.c
> @@ -80,6 +80,7 @@ enum nfs_param {
>         Opt_source,
>         Opt_tcp,
>         Opt_timeo,
> +       Opt_trunkdiscovery,
>         Opt_udp,
>         Opt_v,
>         Opt_vers,
> @@ -180,6 +181,7 @@ static const struct fs_parameter_spec nfs_fs_parameters[] = {
>         fsparam_string("source",        Opt_source),
>         fsparam_flag  ("tcp",           Opt_tcp),
>         fsparam_u32   ("timeo",         Opt_timeo),
> +       fsparam_flag_no("trunkdiscovery", Opt_trunkdiscovery),
>         fsparam_flag  ("udp",           Opt_udp),
>         fsparam_flag  ("v2",            Opt_v),
>         fsparam_flag  ("v3",            Opt_v),
> @@ -529,6 +531,12 @@ static int nfs_fs_context_parse_param(struct fs_context *fc,
>                 else
>                         ctx->flags &= ~NFS_MOUNT_NOCTO;
>                 break;
> +       case Opt_trunkdiscovery:
> +               if (result.negated)
> +                       ctx->flags |= NFS_MOUNT_NOTRUNK_DISCOVERY;
> +               else
> +                       ctx->flags &= ~NFS_MOUNT_NOTRUNK_DISCOVERY;
> +               break;
>         case Opt_ac:
>                 if (result.negated)
>                         ctx->flags |= NFS_MOUNT_NOAC;
> diff --git a/include/linux/nfs_fs_sb.h b/include/linux/nfs_fs_sb.h
> index ca0959e51e81..d0920d7f5f9e 100644
> --- a/include/linux/nfs_fs_sb.h
> +++ b/include/linux/nfs_fs_sb.h
> @@ -151,6 +151,7 @@ struct nfs_server {
>  #define NFS_MOUNT_SOFTREVAL            0x800000
>  #define NFS_MOUNT_WRITE_EAGER          0x01000000
>  #define NFS_MOUNT_WRITE_WAIT           0x02000000
> +#define NFS_MOUNT_NOTRUNK_DISCOVERY    0x04000000
>
>         unsigned int            fattr_valid;    /* Valid attributes */
>         unsigned int            caps;           /* server capabilities */
> --
> 2.27.0
>