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;