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;
+}
+
/*
* 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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