On Tue, 2009-08-04 at 09:58 -0400, Chuck Lever wrote:
> After certain failure modes of an NFS mount, an NFS client should send
> a MOUNTPROC_UMNT request to remove the just-added mount entry from the
> server's mount table. While no-one should rely on the accuracy of the
> server's mount table, sending a UMNT is simply being a good internet
> neighbor.
>
> Since NFS mount processing is handled in the kernel now, we will need
> a function in the kernel's mountd client that can post a MOUNTRPC_UMNT
> request, in order to handle these failure modes.
>
> Signed-off-by: Chuck Lever <chuck.lever@xxxxxxxxxx>
> ---
>
> fs/nfs/internal.h | 1 +
> fs/nfs/mount_clnt.c | 80 +++++++++++++++++++++++++++++++++++++++++++++++++++
> 2 files changed, 81 insertions(+), 0 deletions(-)
>
> diff --git a/fs/nfs/internal.h b/fs/nfs/internal.h
> index 7dd90a6..8d2b71d 100644
> --- a/fs/nfs/internal.h
> +++ b/fs/nfs/internal.h
> @@ -102,6 +102,7 @@ struct nfs_mount_request {
> };
>
> extern int nfs_mount(struct nfs_mount_request *info);
> +extern void nfs_umount(const struct nfs_mount_request *info);
>
> /* client.c */
> extern struct rpc_program nfs_program;
> diff --git a/fs/nfs/mount_clnt.c b/fs/nfs/mount_clnt.c
> index 38ef9ea..e51bf9a 100644
> --- a/fs/nfs/mount_clnt.c
> +++ b/fs/nfs/mount_clnt.c
> @@ -209,6 +209,72 @@ out_mnt_err:
> goto out;
> }
>
> +/**
> + * nfs_umount - Notify a server that we have unmounted this export
> + * @info: pointer to umount request arguments
> + *
> + * MOUNTPROC_UMNT is advisory, so we set a short timeout, and always
> + * use UDP.
> + */
> +void nfs_umount(const struct nfs_mount_request *info)
> +{
> + static const struct rpc_timeout nfs_umnt_timeout = {
> + .to_initval = 1 * HZ,
> + .to_maxval = 3 * HZ,
> + .to_retries = 2,
> + };
> + struct rpc_create_args args = {
> + .protocol = IPPROTO_UDP,
> + .address = info->sap,
> + .addrsize = info->salen,
> + .timeout = &nfs_umnt_timeout,
> + .servername = info->hostname,
> + .program = &mnt_program,
> + .version = info->version,
> + .authflavor = RPC_AUTH_UNIX,
> + .flags = RPC_CLNT_CREATE_NOPING,
> + };
> + struct mountres result;
> + struct rpc_message msg = {
> + .rpc_argp = info->dirpath,
> + .rpc_resp = &result,
> + };
> + struct rpc_clnt *clnt;
> + int status;
> +
> + if (info->noresvport)
> + args.flags |= RPC_CLNT_CREATE_NONPRIVPORT;
> +
> + clnt = rpc_create(&args);
> + if (unlikely(IS_ERR(clnt)))
> + goto out_clnt_err;
> +
> + dprintk("NFS: sending UMNT request for %s:%s\n",
> + (info->hostname ? info->hostname : "server"), info->dirpath);
> +
> + if (info->version == NFS_MNT3_VERSION)
> + msg.rpc_proc = &clnt->cl_procinfo[MOUNTPROC3_UMNT];
> + else
> + msg.rpc_proc = &clnt->cl_procinfo[MOUNTPROC_UMNT];
> +
> + status = rpc_call_sync(clnt, &msg, 0);
> + rpc_shutdown_client(clnt);
> +
> + if (unlikely(status < 0))
> + goto out_call_err;
> +
> + return;
> +
> +out_clnt_err:
> + dprintk("NFS: failed to create UMNT RPC client, status=%ld\n",
> + PTR_ERR(clnt));
> + return;
> +
> +out_call_err:
> + dprintk("NFS: UMNT request failed, status=%d\n", status);
> + return;
Ehem.... I'm removing this.
> +}
> +
> /*
> * XDR encode/decode functions for MOUNT
> */
> @@ -407,6 +473,13 @@ static struct rpc_procinfo mnt_procedures[] = {
> .p_statidx = MOUNTPROC_MNT,
> .p_name = "MOUNT",
> },
> + [MOUNTPROC_UMNT] = {
> + .p_proc = MOUNTPROC_UMNT,
> + .p_encode = (kxdrproc_t)mnt_enc_dirpath,
> + .p_arglen = MNT_enc_dirpath_sz,
> + .p_statidx = MOUNTPROC_UMNT,
> + .p_name = "UMOUNT",
> + },
> };
>
> static struct rpc_procinfo mnt3_procedures[] = {
> @@ -419,6 +492,13 @@ static struct rpc_procinfo mnt3_procedures[] = {
> .p_statidx = MOUNTPROC3_MNT,
> .p_name = "MOUNT",
> },
> + [MOUNTPROC3_UMNT] = {
> + .p_proc = MOUNTPROC3_UMNT,
> + .p_encode = (kxdrproc_t)mnt_enc_dirpath,
> + .p_arglen = MNT_enc_dirpath_sz,
> + .p_statidx = MOUNTPROC3_UMNT,
> + .p_name = "UMOUNT",
> + },
> };
>
>
>
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