[PATCH] fix ext3 in data=writeback mode

When I converted ext3 to use to use direct-to-BIO writeback for
data=writeback mode I forgot that we need to hold a transaction open on
behalf of MAP_SHARED pages.  The fileystem is BUGging in get_block()
because there is no transaction open.

So let's forget that idea for now and send data=writeback mode back to
ext3_writepage.

fs/ext3/inode.c

@@ -1473,7 +1473,7 @@ struct address_space_operations ext3_aops = {
 };
 
 /* For writeback mode, we can use mpage_writepages() */
-
+#if 0	/* Doesn't work for shared mappings */
 static int
 ext3_writepages(struct address_space *mapping, struct writeback_control *wbc)
 {
@@ -1486,12 +1486,12 @@ ext3_writepages(struct address_space *mapping, struct writeback_control *wbc)
 		ret = err;
 	return ret;
 }
+#endif
 
 struct address_space_operations ext3_writeback_aops = {
 	.readpage	= ext3_readpage,	/* BKL not held.  Don't need */
 	.readpages	= ext3_readpages,	/* BKL not held.  Don't need */
 	.writepage	= ext3_writepage,	/* BKL not held.  We take it */
-	.writepages	= ext3_writepages,	/* BKL not held.  Don't need */
 	.sync_page	= block_sync_page,
 	.prepare_write	= ext3_prepare_write,	/* BKL not held.  We take it */
 	.commit_write	= ext3_commit_write,	/* BKL not held.  We take it */