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 <lai.siyao@intel.com>
Signed-off-by: Niu Yawei <yawei.niu@intel.com>
Signed-off-by: Jan Kara <jack@suse.cz>
diff --git a/fs/quota/quota.c b/fs/quota/quota.c
index ff3f0b3..7562164 100644
--- a/fs/quota/quota.c
+++ b/fs/quota/quota.c
@@ -79,13 +79,13 @@
{
__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;