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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>
This commit is contained in:
Niu Yawei 2014-06-04 12:19:12 +08:00 committed by Jan Kara
parent d68aab6b8f
commit 606cdcca04
1 changed files with 3 additions and 3 deletions
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6
fs/quota/quota.c
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@ -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;