From ba9b584c1dc37851d9c6ca6d0d2ccba55d9aad04 Mon Sep 17 00:00:00 2001 From: Chuck Lever Date: Fri, 14 Sep 2012 17:24:02 -0400 Subject: SUNRPC: Introduce rpc_clone_client_set_auth() An ULP is supposed to be able to replace a GSS rpc_auth object with another GSS rpc_auth object using rpcauth_create(). However, rpcauth_create() in 3.5 reliably fails with -EEXIST in this case. This is because when gss_create() attempts to create the upcall pipes, sometimes they are already there. For example if a pipe FS mount event occurs, or a previous GSS flavor was in use for this rpc_clnt. It turns out that's not the only problem here. While working on a fix for the above problem, we noticed that replacing an rpc_clnt's rpc_auth is not safe, since dereferencing the cl_auth field is not protected in any way. So we're deprecating the ability of rpcauth_create() to switch an rpc_clnt's security flavor during normal operation. Instead, let's add a fresh API that clones an rpc_clnt and gives the clone a new flavor before it's used. This makes immediate use of the new __rpc_clone_client() helper. This can be used in a similar fashion to rpcauth_create() when a client is hunting for the correct security flavor. Instead of replacing an rpc_clnt's security flavor in a loop, the ULP replaces the whole rpc_clnt. To fix the -EEXIST problem, any ULP logic that relies on replacing an rpc_clnt's rpc_auth with rpcauth_create() must be changed to use this API instead. Signed-off-by: Chuck Lever Signed-off-by: Trond Myklebust --- fs/nfs/nfs4namespace.c | 14 +------------- 1 file changed, 1 insertion(+), 13 deletions(-) (limited to 'fs/nfs/nfs4namespace.c') diff --git a/fs/nfs/nfs4namespace.c b/fs/nfs/nfs4namespace.c index 4fdeb1b7042e..79fbb61ce202 100644 --- a/fs/nfs/nfs4namespace.c +++ b/fs/nfs/nfs4namespace.c @@ -192,25 +192,13 @@ out: 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 ((int)flavor < 0) return ERR_PTR((int)flavor); - clone = rpc_clone_client(clnt); - if (IS_ERR(clone)) - return clone; - - auth = rpcauth_create(flavor, clone); - if (IS_ERR(auth)) { - rpc_shutdown_client(clone); - clone = ERR_PTR(-EIO); - } - - return clone; + return rpc_clone_client_set_auth(clnt, flavor); } static struct vfsmount *try_location(struct nfs_clone_mount *mountdata, -- cgit v1.2.3