[PATCH] fix xip sparse file handling in ext2

Oliver Paukstadt from our test department is testing the xip patches in
Linus' git-tree.  He found a problem that shows when reading a file that
contains sparse blocks (holes) on a -o xip mounted ext2 filesystem: the
BUG_ON() in fs/ext2/xip.c:40 triggers where it should not.  The problem was
introduced by a cleanup in my previous patch, this patch fixes it.
Signed-off-by: Carsten Otte <cotte@de.ibm.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

fs/ext2/xip.c

@@ -36,7 +36,7 @@ __ext2_get_sector(struct inode *inode, sector_t offset, int create,
 	*result = tmp.b_blocknr;
 
 	/* did we get a sparse block (hole in the file)? */
-	if (!(*result)) {
+	if (!tmp.b_blocknr && !rc) {
 		BUG_ON(create);
 		rc = -ENODATA;
 	}