NFSv4: Handle NFS4ERR_WRONGSEC outside of nfs4_handle_exception()

I only want to try other secflavors during an initial mount if
NFS4ERR_WRONGSEC is returned.  nfs4_handle_exception() could
potentially map other errors to EPERM, so we should handle this
error specially for correctness.

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

1 files changed, 23 insertions, 5 deletions

diff --git a/fs/nfs/nfs4proc.c b/fs/nfs/nfs4proc.c
index e7e2077eebd9..628e35f75307 100644
--- a/fs/nfs/nfs4proc.c
+++ b/fs/nfs/nfs4proc.c
@@ -2186,9 +2186,14 @@ static int nfs4_lookup_root(struct nfs_server *server, struct nfs_fh *fhandle,
         struct nfs4_exception exception = { };
         int err;
         do {
-                err = nfs4_handle_exception(server,
-                                _nfs4_lookup_root(server, fhandle, info),
-                                &exception);
+                err = _nfs4_lookup_root(server, fhandle, info);
+                switch (err) {
+                case 0:
+                case -NFS4ERR_WRONGSEC:
+                        break;
+                default:
+                        err = nfs4_handle_exception(server, err, &exception);
+                }
         } while (exception.retry);
         return err;
 }
@@ -2221,10 +2226,19 @@ static int nfs4_find_root_sec(struct nfs_server *server, struct nfs_fh *fhandle,
 
         for (i = 0; i < len; i++) {
                 status = nfs4_lookup_root_sec(server, fhandle, info, flav_array[i]);
-                if (status == -EPERM || status == -EACCES)
+                if (status == -NFS4ERR_WRONGSEC || status == -EACCES)
                         continue;
                 break;
         }
+        /*
+         * -EACCESS could mean that the user doesn't have correct permissions
+         * to access the mount.  It could also mean that we tried to mount
+         * with a gss auth flavor, but rpc.gssd isn't running.  Either way,
+         * existing mount programs don't handle -EACCES very well so it should
+         * be mapped to -EPERM instead.
+         */
+        if (status == -EACCES)
+                status = -EPERM;
         return status;
 }
 
@@ -2235,7 +2249,11 @@ static int nfs4_proc_get_root(struct nfs_server *server, struct nfs_fh *fhandle,
                               struct nfs_fsinfo *info)
 {
         int status = nfs4_lookup_root(server, fhandle, info);
-        if ((status == -EPERM) && !(server->flags & NFS_MOUNT_SECFLAVOUR))
+        if ((status == -NFS4ERR_WRONGSEC) && !(server->flags & NFS_MOUNT_SECFLAVOUR))
+                /*
+                 * A status of -NFS4ERR_WRONGSEC will be mapped to -EPERM
+                 * by nfs4_map_errors() as this function exits.
+                 */
                 status = nfs4_find_root_sec(server, fhandle, info);
         if (status == 0)
                 status = nfs4_server_capabilities(server, fhandle);