new helper: file_inode(file)

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
diff --git a/fs/f2fs/dir.c b/fs/f2fs/dir.c
index 951ed52..fda0bcc 100644
--- a/fs/f2fs/dir.c
+++ b/fs/f2fs/dir.c
@@ -603,7 +603,7 @@
 static int f2fs_readdir(struct file *file, void *dirent, filldir_t filldir)
 {
 	unsigned long pos = file->f_pos;
-	struct inode *inode = file->f_dentry->d_inode;
+	struct inode *inode = file_inode(file);
 	unsigned long npages = dir_blocks(inode);
 	unsigned char *types = NULL;
 	unsigned int bit_pos = 0, start_bit_pos = 0;