ntfs3: refactor ntfs_writepages

Handle the resident case with an explicit generic_writepages call instead
of using the obscure overload that makes mpage_writepages with a NULL
get_block do the same thing.
Signed-off-by: NChristoph Hellwig <hch@lst.de>
Reviewed-by: NJan Kara <jack@suse.cz>
Signed-off-by: NMatthew Wilcox (Oracle) <willy@infradead.org>

fs/ntfs3/inode.c

@@ -851,12 +851,10 @@ static int ntfs_writepage(struct page *page, struct writeback_control *wbc)
 static int ntfs_writepages(struct address_space *mapping,
 			   struct writeback_control *wbc)
 {
-	struct inode *inode = mapping->host;
-	struct ntfs_inode *ni = ntfs_i(inode);
 	/* Redirect call to 'ntfs_writepage' for resident files. */
-	get_block_t *get_block = is_resident(ni) ? NULL : &ntfs_get_block;
-
-	return mpage_writepages(mapping, wbc, get_block);
+	if (is_resident(ntfs_i(mapping->host)))
+		return generic_writepages(mapping, wbc);
+	return mpage_writepages(mapping, wbc, ntfs_get_block);
 }
 
 static int ntfs_get_block_write_begin(struct inode *inode, sector_t vbn,