[PATCH 1/3] Add network context to struct nfs_client and make NFSv3 use it.

[Rob Landley <rlandley@parallels.com>]

From: Rob Landley <rlandley@parallels.com>

This patch:

  Adds struct net *cl_net to struct nfs_client.
  Intializes it from mount process context.
  Copies it down through nfs_client_initdata and similar.
  Replaces existing init_net uses with cl_net.
  Adds net_eq() checks to nfs_match_client() and nfs_compare_super_address().

Remount copies the existing network context rather than any associated with
the new mount process.  NFSv4 is still using init_net.  Reference counting
for struct net follows the struct nfs_client object lifetimes (pinned by
task context outside of that).

Signed-off-by: Rob Landley <rlandley@parallels.com>
---

 fs/nfs/client.c           |   13 ++++++++++++-
 fs/nfs/internal.h         |    2 ++
 fs/nfs/mount_clnt.c       |    4 ++--
 fs/nfs/super.c            |   15 +++++++++++++++
 include/linux/nfs_fs_sb.h |    1 +
 5 files changed, 32 insertions(+), 3 deletions(-)

diff --git a/fs/nfs/client.c b/fs/nfs/client.c
index 139be96..99bfaa6 100644
--- a/fs/nfs/client.c
+++ b/fs/nfs/client.c
@@ -130,6 +130,7 @@ struct rpc_program		nfsacl_program = {
 
 struct nfs_client_initdata {
 	const char *hostname;
+	struct net *net;
 	const struct sockaddr *addr;
 	size_t addrlen;
 	const struct nfs_rpc_ops *rpc_ops;
@@ -157,6 +158,7 @@ static struct nfs_client *nfs_alloc_client(const struct nfs_client_initdata *cl_
 	atomic_set(&clp->cl_count, 1);
 	clp->cl_cons_state = NFS_CS_INITING;
 
+	clp->cl_net = get_net(cl_init->net);
 	memcpy(&clp->cl_addr, cl_init->addr, cl_init->addrlen);
 	clp->cl_addrlen = cl_init->addrlen;
 
@@ -196,6 +198,7 @@ static struct nfs_client *nfs_alloc_client(const struct nfs_client_initdata *cl_
 	return clp;
 
 error_cleanup:
+	put_net(clp->cl_net);
 	kfree(clp);
 error_0:
 	return ERR_PTR(err);
@@ -290,6 +293,9 @@ static void nfs_free_client(struct nfs_client *clp)
 	if (clp->cl_machine_cred != NULL)
 		put_rpccred(clp->cl_machine_cred);
 
+	if (clp->cl_net)
+		put_net(clp->cl_net);
+
 	kfree(clp->cl_hostname);
 	kfree(clp);
 
@@ -473,6 +479,8 @@ static struct nfs_client *nfs_match_client(const struct nfs_client_initdata *dat
 		if (clp->cl_minorversion != data->minorversion)
 			continue;
 		/* Match the full socket address */
+		if (!net_eq(clp->cl_net, data->net))
+			continue;
 		if (!nfs_sockaddr_cmp(sap, clap))
 			continue;
 
@@ -636,7 +644,7 @@ static int nfs_create_rpc_client(struct nfs_client *clp,
 {
 	struct rpc_clnt		*clnt = NULL;
 	struct rpc_create_args args = {
-		.net		= &init_net,
+		.net		= clp->cl_net,
 		.protocol	= clp->cl_proto,
 		.address	= (struct sockaddr *)&clp->cl_addr,
 		.addrsize	= clp->cl_addrlen,
@@ -821,6 +829,7 @@ static int nfs_init_server(struct nfs_server *server,
 {
 	struct nfs_client_initdata cl_init = {
 		.hostname = data->nfs_server.hostname,
+		.net = data->net,
 		.addr = (const struct sockaddr *)&data->nfs_server.address,
 		.addrlen = data->nfs_server.addrlen,
 		.rpc_ops = &nfs_v2_clientops,
@@ -1386,6 +1395,7 @@ static int nfs4_set_client(struct nfs_server *server,
 {
 	struct nfs_client_initdata cl_init = {
 		.hostname = hostname,
+		.net = &init_net,
 		.addr = addr,
 		.addrlen = addrlen,
 		.rpc_ops = &nfs_v4_clientops,
@@ -1438,6 +1448,7 @@ struct nfs_client *nfs4_set_ds_client(struct nfs_client* mds_clp,
 {
 	struct nfs_client_initdata cl_init = {
 		.addr = ds_addr,
+		.net = &init_net,
 		.addrlen = ds_addrlen,
 		.rpc_ops = &nfs_v4_clientops,
 		.proto = ds_proto,
diff --git a/fs/nfs/internal.h b/fs/nfs/internal.h
index 72e0bdd..006ab1a 100644
--- a/fs/nfs/internal.h
+++ b/fs/nfs/internal.h
@@ -86,6 +86,7 @@ struct nfs_parsed_mount_data {
 	unsigned int		version;
 	unsigned int		minorversion;
 	char			*fscache_uniq;
+	struct net		*net;
 
 	struct {
 		struct sockaddr_storage	address;
@@ -111,6 +112,7 @@ struct nfs_parsed_mount_data {
 /* mount_clnt.c */
 struct nfs_mount_request {
 	struct sockaddr		*sap;
+	struct net		*net;
 	size_t			salen;
 	char			*hostname;
 	char			*dirpath;
diff --git a/fs/nfs/mount_clnt.c b/fs/nfs/mount_clnt.c
index d4c2d6b..4fbe3a8 100644
--- a/fs/nfs/mount_clnt.c
+++ b/fs/nfs/mount_clnt.c
@@ -153,7 +153,7 @@ int nfs_mount(struct nfs_mount_request *info)
 		.rpc_resp	= &result,
 	};
 	struct rpc_create_args args = {
-		.net		= &init_net,
+		.net		= info->net,
 		.protocol	= info->protocol,
 		.address	= info->sap,
 		.addrsize	= info->salen,
@@ -225,7 +225,7 @@ void nfs_umount(const struct nfs_mount_request *info)
 		.to_retries = 2,
 	};
 	struct rpc_create_args args = {
-		.net		= &init_net,
+		.net		= info->net,
 		.protocol	= IPPROTO_UDP,
 		.address	= info->sap,
 		.addrsize	= info->salen,
diff --git a/fs/nfs/super.c b/fs/nfs/super.c
index 2b8e9a5..b0d869f 100644
--- a/fs/nfs/super.c
+++ b/fs/nfs/super.c
@@ -53,6 +53,7 @@
 #include <linux/nfs_xdr.h>
 #include <linux/magic.h>
 #include <linux/parser.h>
+#include <linux/user_namespace.h>
 
 #include <asm/system.h>
 #include <asm/uaccess.h>
@@ -1572,6 +1573,7 @@ static int nfs_try_mount(struct nfs_parsed_mount_data *args,
 	struct nfs_mount_request request = {
 		.sap		= (struct sockaddr *)
 						&args->mount_server.address,
+		.net		= args->net,
 		.dirpath	= args->nfs_server.export_path,
 		.protocol	= args->mount_server.protocol,
 		.fh		= root_fh,
@@ -1726,6 +1728,11 @@ static int nfs_validate_mount_data(void *options,
 	if (data == NULL)
 		goto out_no_data;
 
+	/* Grab network context from mount process. We'll increment the
+	   reference count when we copy it to nfs_client->cl_net. */
+
+	args->net = current->nsproxy->net_ns;
+
 	switch (data->version) {
 	case 1:
 		data->namlen = 0;
@@ -1971,6 +1978,9 @@ nfs_remount(struct super_block *sb, int *flags, char *raw_data)
 	memcpy(&data->nfs_server.address, &nfss->nfs_client->cl_addr,
 		data->nfs_server.addrlen);
 
+	/* Use original mount's network context, not remount process's */
+	data->net = nfss->nfs_client->cl_net;
+
 	/* overwrite those values with any that were specified */
 	error = nfs_parse_mount_options((char *)options, data);
 	if (error < 0)
@@ -2119,6 +2129,9 @@ static int nfs_compare_super_address(struct nfs_server *server1,
 	if (sap1->sa_family != sap2->sa_family)
 		return 0;
 
+	if (!net_eq(server1->nfs_client->cl_net, server2->nfs_client->cl_net))
+		return 0;
+
 	switch (sap1->sa_family) {
 	case AF_INET: {
 		struct sockaddr_in *sin1 = (struct sockaddr_in *)sap1;
@@ -2478,6 +2491,8 @@ static int nfs4_validate_mount_data(void *options,
 	if (data == NULL)
 		goto out_no_data;
 
+	args->net = &init_net;
+
 	switch (data->version) {
 	case 1:
 		if (data->host_addrlen > sizeof(args->nfs_server.address))
diff --git a/include/linux/nfs_fs_sb.h b/include/linux/nfs_fs_sb.h
index 216cea5..45286dc 100644
--- a/include/linux/nfs_fs_sb.h
+++ b/include/linux/nfs_fs_sb.h
@@ -33,6 +33,7 @@ struct nfs_client {
 #define NFS_CS_STOP_RENEW	4		/* no more state to renew */
 #define NFS_CS_CHECK_LEASE_TIME	5		/* need to check lease time */
 	struct sockaddr_storage	cl_addr;	/* server identifier */
+	struct net *		cl_net;		/* network context */
 	size_t			cl_addrlen;
 	char *			cl_hostname;	/* hostname of server */
 	struct list_head	cl_share_link;	/* link in global client list */