From: Jan Kara <jack@suse.cz>
Date: Tue, 29 Mar 2016 15:20:10 +0000 (+0200)
Subject: quota: Handle Q_GETNEXTQUOTA when quota is disabled
X-Git-Tag: v4.14-rc1~3483^2~1
X-Git-Url: http://review.tizen.org/git/?a=commitdiff_plain;h=17e8a8936c3f28085a858e65baee90dff5e8d48b;p=platform%2Fkernel%2Flinux-rpi.git

quota: Handle Q_GETNEXTQUOTA when quota is disabled

Currently we oopsed when Q_GETNEXTQUOTA got called when quota was
disabled. Properly check whether quota is enabled for the filesystem
before calling into quota format handler.

Reported-by: Ted Tso <tytso@mit.edu>
Signed-off-by: Jan Kara <jack@suse.cz>
---

diff --git a/fs/quota/dquot.c b/fs/quota/dquot.c
index ba827da..ff21980 100644
--- a/fs/quota/dquot.c
+++ b/fs/quota/dquot.c
@@ -2047,11 +2047,20 @@ int dquot_get_next_id(struct super_block *sb, struct kqid *qid)
 	struct quota_info *dqopt = sb_dqopt(sb);
 	int err;
 
-	if (!dqopt->ops[qid->type]->get_next_id)
-		return -ENOSYS;
+	mutex_lock(&dqopt->dqonoff_mutex);
+	if (!sb_has_quota_active(sb, qid->type)) {
+		err = -ESRCH;
+		goto out;
+	}
+	if (!dqopt->ops[qid->type]->get_next_id) {
+		err = -ENOSYS;
+		goto out;
+	}
 	mutex_lock(&dqopt->dqio_mutex);
 	err = dqopt->ops[qid->type]->get_next_id(sb, qid);
 	mutex_unlock(&dqopt->dqio_mutex);
+out:
+	mutex_unlock(&dqopt->dqonoff_mutex);
 
 	return err;
 }