new helper: file_inode(file)

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
diff --git a/fs/coda/inode.c b/fs/coda/inode.c
index be2aa49..6df708c 100644
--- a/fs/coda/inode.c
+++ b/fs/coda/inode.c
@@ -129,7 +129,7 @@
 	f = fdget(data->fd);
 	if (!f.file)
 		goto Ebadf;
-	inode = f.file->f_path.dentry->d_inode;
+	inode = file_inode(f.file);
 	if (!S_ISCHR(inode->i_mode) || imajor(inode) != CODA_PSDEV_MAJOR) {
 		fdput(f);
 		goto Ebadf;