hfs: fix B-tree corruption after insertion at position 0

Fix B-tree corruption when a new record is inserted at position 0 in the
node in hfs_brec_insert().

This is an identical change to the corresponding hfs b-tree code to Sergei
Antonov's "hfsplus: fix B-tree corruption after insertion at position 0",
to keep similar code paths in the hfs and hfsplus drivers in sync, where
appropriate.

Signed-off-by: Hin-Tak Leung <[email protected]>
Cc: Sergei Antonov <[email protected]>
Cc: Joe Perches <[email protected]>
Reviewed-by: Vyacheslav Dubeyko <[email protected]>
Cc: Anton Altaparmakov <[email protected]>
Cc: Al Viro <[email protected]>
Cc: Christoph Hellwig <[email protected]>
Cc: <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Signed-off-by: Linus Torvalds <[email protected]>

fs/hfs/brec.c

@@ -131,13 +131,16 @@ int hfs_brec_insert(struct hfs_find_data *fd, void *entry, int entry_len)
 	hfs_bnode_write(node, entry, data_off + key_len, entry_len);
 	hfs_bnode_dump(node);
 
-	if (new_node) {
-		/* update parent key if we inserted a key
-		 * at the start of the first node
-		 */
-		if (!rec && new_node != node)
-			hfs_brec_update_parent(fd);
+	/*
+	 * update parent key if we inserted a key
+	 * at the start of the node and it is not the new node
+	 */
+	if (!rec && new_node != node) {
+		hfs_bnode_read_key(node, fd->search_key, data_off + size);
+		hfs_brec_update_parent(fd);
+	}
 
+	if (new_node) {
 		hfs_bnode_put(fd->bnode);
 		if (!new_node->parent) {
 			hfs_btree_inc_height(tree);
@@ -166,9 +169,6 @@ int hfs_brec_insert(struct hfs_find_data *fd, void *entry, int entry_len)
 		goto again;
 	}
 
-	if (!rec)
-		hfs_brec_update_parent(fd);
-
 	return 0;
 }
 
@@ -366,6 +366,8 @@ static int hfs_brec_update_parent(struct hfs_find_data *fd)
 	if (IS_ERR(parent))
 		return PTR_ERR(parent);
 	__hfs_brec_find(parent, fd);
+	if (fd->record < 0)
+		return -ENOENT;
 	hfs_bnode_dump(parent);
 	rec = fd->record;