NFS: Do secinfo as part of lookup

Whenever lookup sees wrongsec do a secinfo and retry the lookup to find
attributes of the file or directory, such as "is this a referral
mountpoint?".  This also allows me to remove handling -NFS4ERR_WRONSEC
as part of getattr xdr decoding.

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

1 files changed, 52 insertions, 0 deletions

diff --git a/fs/nfs/nfs4namespace.c b/fs/nfs/nfs4namespace.c
index 7483a177dc97..9f8681bf90de 100644
--- a/fs/nfs/nfs4namespace.c
+++ b/fs/nfs/nfs4namespace.c
@@ -132,6 +132,58 @@ static size_t nfs_parse_server_name(char *string, size_t len,
         return ret;
 }
 
+static rpc_authflavor_t nfs4_negotiate_security(struct inode *inode, struct qstr *name)
+{
+        struct page *page;
+        struct nfs4_secinfo_flavors *flavors;
+        rpc_authflavor_t flavor;
+        int err;
+
+        page = alloc_page(GFP_KERNEL);
+        if (!page)
+                return -ENOMEM;
+        flavors = page_address(page);
+
+        err = nfs4_proc_secinfo(inode, name, flavors);
+        if (err < 0) {
+                flavor = err;
+                goto out;
+        }
+
+        flavor = nfs_find_best_sec(flavors);
+
+out:
+        put_page(page);
+        return flavor;
+}
+
+/*
+ * Please call rpc_shutdown_client() when you are done with this client.
+ */
+struct rpc_clnt *nfs4_create_sec_client(struct rpc_clnt *clnt, struct inode *inode,
+                                        struct qstr *name)
+{
+        struct rpc_clnt *clone;
+        struct rpc_auth *auth;
+        rpc_authflavor_t flavor;
+
+        flavor = nfs4_negotiate_security(inode, name);
+        if (flavor < 0)
+                return ERR_PTR(flavor);
+
+        clone = rpc_clone_client(clnt);
+        if (IS_ERR(clone))
+                return clone;
+
+        auth = rpcauth_create(flavor, clone);
+        if (!auth) {
+                rpc_shutdown_client(clone);
+                clone = ERR_PTR(-EIO);
+        }
+
+        return clone;
+}
+
 static struct vfsmount *try_location(struct nfs_clone_mount *mountdata,
                                      char *page, char *page2,
                                      const struct nfs4_fs_location *location)