quota: protect Q_GETFMT by dqonoff_mutex

dqptr_sem will go away. Protect Q_GETFMT quotactl by dqonoff_mutex instead. This is also enough to make sure quota info will not go away while we are looking at it. Signed-off-by: Lai Siyao <[email protected]> Signed-off-by: Niu Yawei <[email protected]> Signed-off-by: Jan Kara <[email protected]>
ambv · Jul 15, 2014 · 606cdcc · 606cdcc
1 parent d68aab6
commit 606cdcc
Showing 1 changed file with 3 additions and 3 deletions.
diff --git a/fs/quota/quota.c b/fs/quota/quota.c
@@ -79,13 +79,13 @@ static int quota_getfmt(struct super_block *sb, int type, void __user *addr)
 {
 	__u32 fmt;
 
-	down_read(&sb_dqopt(sb)->dqptr_sem);
+	mutex_lock(&sb_dqopt(sb)->dqonoff_mutex);
 	if (!sb_has_quota_active(sb, type)) {
-		up_read(&sb_dqopt(sb)->dqptr_sem);
+		mutex_unlock(&sb_dqopt(sb)->dqonoff_mutex);
 		return -ESRCH;
 	}
 	fmt = sb_dqopt(sb)->info[type].dqi_format->qf_fmt_id;
-	up_read(&sb_dqopt(sb)->dqptr_sem);
+	mutex_unlock(&sb_dqopt(sb)->dqonoff_mutex);
 	if (copy_to_user(addr, &fmt, sizeof(fmt)))
 		return -EFAULT;
 	return 0;