quota: paranoia: check quota tree root

Root level in quota tree must be already allocated otherwise this block could be used for something else. Signed-off-by: Konstantin Khlebnikov <[email protected]> Signed-off-by: Jan Kara <[email protected]>
neviim · Mar 4, 2015 · 69a25ee · 69a25ee
1 parent 5bcd3b6
commit 69a25ee
Showing 1 changed file with 7 additions and 0 deletions.
diff --git a/fs/quota/quota_tree.c b/fs/quota/quota_tree.c
@@ -349,6 +349,13 @@ static inline int dq_insert_tree(struct qtree_mem_dqinfo *info,
 				 struct dquot *dquot)
 {
 	int tmp = QT_TREEOFF;
+
+#ifdef __QUOTA_QT_PARANOIA
+	if (info->dqi_blocks <= QT_TREEOFF) {
+		quota_error(dquot->dq_sb, "Quota tree root isn't allocated!");
+		return -EIO;
+	}
+#endif
 	return do_insert_tree(info, dquot, &tmp, 0);
 }