new helper: file_inode(file)

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
diff --git a/fs/buffer.c b/fs/buffer.c
index 7a75c3e..b8a8b4d 100644
--- a/fs/buffer.c
+++ b/fs/buffer.c
@@ -2332,7 +2332,7 @@
 			 get_block_t get_block)
 {
 	struct page *page = vmf->page;
-	struct inode *inode = vma->vm_file->f_path.dentry->d_inode;
+	struct inode *inode = file_inode(vma->vm_file);
 	unsigned long end;
 	loff_t size;
 	int ret;
@@ -2371,7 +2371,7 @@
 		   get_block_t get_block)
 {
 	int ret;
-	struct super_block *sb = vma->vm_file->f_path.dentry->d_inode->i_sb;
+	struct super_block *sb = file_inode(vma->vm_file)->i_sb;
 
 	sb_start_pagefault(sb);