NFS: Fix following referral mount points with different security

I create a new proc_lookup_mountpoint() to use when submounting an NFS
v4 share.  This function returns an rpc_clnt to use for performing an
fs_locations() call on a referral's mountpoint.

Signed-off-by: Bryan Schumaker <bjschuma@netapp.com>
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>

1 files changed, 30 insertions, 10 deletions

diff --git a/fs/nfs/nfs4proc.c b/fs/nfs/nfs4proc.c
index 3d92fe6be780..75eb883ed4ce 100644
--- a/fs/nfs/nfs4proc.c
+++ b/fs/nfs/nfs4proc.c
@@ -2377,8 +2377,9 @@ static int nfs4_proc_get_root(struct nfs_server *server, struct nfs_fh *fhandle,
  * Note that we'll actually follow the referral later when
  * we detect fsid mismatch in inode revalidation
  */
-static int nfs4_get_referral(struct inode *dir, const struct qstr *name,
-			     struct nfs_fattr *fattr, struct nfs_fh *fhandle)
+static int nfs4_get_referral(struct rpc_clnt *client, struct inode *dir,
+			     const struct qstr *name, struct nfs_fattr *fattr,
+			     struct nfs_fh *fhandle)
 {
 	int status = -ENOMEM;
 	struct page *page = NULL;
@@ -2391,7 +2392,7 @@ static int nfs4_get_referral(struct inode *dir, const struct qstr *name,
 	if (locations == NULL)
 		goto out;
 
-	status = nfs4_proc_fs_locations(dir, name, locations, page);
+	status = nfs4_proc_fs_locations(client, dir, name, locations, page);
 	if (status != 0)
 		goto out;
 	/* Make sure server returned a different fsid for the referral */
@@ -2550,7 +2551,7 @@ static int nfs4_proc_lookup_common(struct rpc_clnt **clnt, struct inode *dir,
 			err = -ENOENT;
 			goto out;
 		case -NFS4ERR_MOVED:
-			err = nfs4_get_referral(dir, name, fattr, fhandle);
+			err = nfs4_get_referral(client, dir, name, fattr, fhandle);
 			goto out;
 		case -NFS4ERR_WRONGSEC:
 			err = -EPERM;
@@ -2591,6 +2592,21 @@ static int nfs4_proc_lookup(struct rpc_clnt *clnt, struct inode *dir, struct qst
 	return status;
 }
 
+struct rpc_clnt *
+nfs4_proc_lookup_mountpoint(struct inode *dir, struct qstr *name,
+			    struct nfs_fh *fhandle, struct nfs_fattr *fattr)
+{
+	int status;
+	struct rpc_clnt *client = rpc_clone_client(NFS_CLIENT(dir));
+
+	status = nfs4_proc_lookup_common(&client, dir, name, fhandle, fattr);
+	if (status < 0) {
+		rpc_shutdown_client(client);
+		return ERR_PTR(status);
+	}
+	return client;
+}
+
 static int _nfs4_proc_access(struct inode *inode, struct nfs_access_entry *entry)
 {
 	struct nfs_server *server = NFS_SERVER(inode);
@@ -4951,8 +4967,10 @@ static void nfs_fixup_referral_attributes(struct nfs_fattr *fattr)
 	fattr->nlink = 2;
 }
 
-static int _nfs4_proc_fs_locations(struct inode *dir, const struct qstr *name,
-		struct nfs4_fs_locations *fs_locations, struct page *page)
+static int _nfs4_proc_fs_locations(struct rpc_clnt *client, struct inode *dir,
+				   const struct qstr *name,
+				   struct nfs4_fs_locations *fs_locations,
+				   struct page *page)
 {
 	struct nfs_server *server = NFS_SERVER(dir);
 	u32 bitmask[2] = {
@@ -4986,19 +5004,21 @@ static int _nfs4_proc_fs_locations(struct inode *dir, const struct qstr *name,
 	nfs_fattr_init(&fs_locations->fattr);
 	fs_locations->server = server;
 	fs_locations->nlocations = 0;
-	status = nfs4_call_sync(server->client, server, &msg, &args.seq_args, &res.seq_res, 0);
+	status = nfs4_call_sync(client, server, &msg, &args.seq_args, &res.seq_res, 0);
 	dprintk("%s: returned status = %d\n", __func__, status);
 	return status;
 }
 
-int nfs4_proc_fs_locations(struct inode *dir, const struct qstr *name,
-		struct nfs4_fs_locations *fs_locations, struct page *page)
+int nfs4_proc_fs_locations(struct rpc_clnt *client, struct inode *dir,
+			   const struct qstr *name,
+			   struct nfs4_fs_locations *fs_locations,
+			   struct page *page)
 {
 	struct nfs4_exception exception = { };
 	int err;
 	do {
 		err = nfs4_handle_exception(NFS_SERVER(dir),
-				_nfs4_proc_fs_locations(dir, name, fs_locations, page),
+				_nfs4_proc_fs_locations(client, dir, name, fs_locations, page),
 				&exception);
 	} while (exception.retry);
 	return err;