hfs: Call hfs_write_begin() and generic_write_end() directly

There is only one kind of write_begin/write_end aops, so we don't need
to look up which aop it is, just make hfs_write_begin() available to
this file and call it directly.
Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Reviewed-by: Christoph Hellwig <hch@lst.de>

fs/hfs/extent.c

@@ -491,10 +491,10 @@ void hfs_file_truncate(struct inode *inode)
 
 		/* XXX: Can use generic_cont_expand? */
 		size = inode->i_size - 1;
-		res = pagecache_write_begin(NULL, mapping, size+1, 0, 0,
-					    &page, &fsdata);
+		res = hfs_write_begin(NULL, mapping, size + 1, 0, &page,
+				&fsdata);
 		if (!res) {
-			res = pagecache_write_end(NULL, mapping, size+1, 0, 0,
+			res = generic_write_end(NULL, mapping, size + 1, 0, 0,
 					page, fsdata);
 		}
 		if (res)

fs/hfs/hfs_fs.h

@@ -201,6 +201,8 @@ extern int hfs_get_block(struct inode *, sector_t, struct buffer_head *, int);
 extern const struct address_space_operations hfs_aops;
 extern const struct address_space_operations hfs_btree_aops;
 
+int hfs_write_begin(struct file *file, struct address_space *mapping,
+		loff_t pos, unsigned len, struct page **pagep, void **fsdata);
 extern struct inode *hfs_new_inode(struct inode *, const struct qstr *, umode_t);
 extern void hfs_inode_write_fork(struct inode *, struct hfs_extent *, __be32 *, __be32 *);
 extern int hfs_write_inode(struct inode *, struct writeback_control *);

fs/hfs/inode.c

@@ -49,9 +49,8 @@ static void hfs_write_failed(struct address_space *mapping, loff_t to)
 	}
 }
 
-static int hfs_write_begin(struct file *file, struct address_space *mapping,
-			loff_t pos, unsigned len,
-			struct page **pagep, void **fsdata)
+int hfs_write_begin(struct file *file, struct address_space *mapping,
+		loff_t pos, unsigned len, struct page **pagep, void **fsdata)
 {
 	int ret;