new helper: file_inode(file)

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
diff --git a/fs/afs/write.c b/fs/afs/write.c
index 9aa52d9..7e03ead 100644
--- a/fs/afs/write.c
+++ b/fs/afs/write.c
@@ -120,7 +120,7 @@
 		    struct page **pagep, void **fsdata)
 {
 	struct afs_writeback *candidate, *wb;
-	struct afs_vnode *vnode = AFS_FS_I(file->f_dentry->d_inode);
+	struct afs_vnode *vnode = AFS_FS_I(file_inode(file));
 	struct page *page;
 	struct key *key = file->private_data;
 	unsigned from = pos & (PAGE_CACHE_SIZE - 1);
@@ -245,7 +245,7 @@
 		  loff_t pos, unsigned len, unsigned copied,
 		  struct page *page, void *fsdata)
 {
-	struct afs_vnode *vnode = AFS_FS_I(file->f_dentry->d_inode);
+	struct afs_vnode *vnode = AFS_FS_I(file_inode(file));
 	loff_t i_size, maybe_i_size;
 
 	_enter("{%x:%u},{%lx}",
@@ -627,8 +627,7 @@
 ssize_t afs_file_write(struct kiocb *iocb, const struct iovec *iov,
 		       unsigned long nr_segs, loff_t pos)
 {
-	struct dentry *dentry = iocb->ki_filp->f_path.dentry;
-	struct afs_vnode *vnode = AFS_FS_I(dentry->d_inode);
+	struct afs_vnode *vnode = AFS_FS_I(file_inode(iocb->ki_filp));
 	ssize_t result;
 	size_t count = iov_length(iov, nr_segs);