2 files changed, 10 insertions, 2 deletions

diff --git a/fs/quota/dquot.c b/fs/quota/dquot.c
index cfc8dcc16043..9cd5f63715c0 100644
--- a/fs/quota/dquot.c
+++ b/fs/quota/dquot.c
@@ -528,7 +528,7 @@ restart:
                 if (atomic_read(&dquot->dq_count)) {
                         DEFINE_WAIT(wait);
 
-                        atomic_inc(&dquot->dq_count);
+                        dqgrab(dquot);
                         prepare_to_wait(&dquot->dq_wait_unused, &wait,
                                         TASK_UNINTERRUPTIBLE);
                         spin_unlock(&dq_list_lock);
@@ -632,7 +632,7 @@ int dquot_writeback_dquots(struct super_block *sb, int type)
                         /* Now we have active dquot from which someone is
                          * holding reference so we can safely just increase
                          * use count */
-                        atomic_inc(&dquot->dq_count);
+                        dqgrab(dquot);
                         spin_unlock(&dq_list_lock);
                         dqstats_inc(DQST_LOOKUPS);
                         err = sb->dq_op->write_dquot(dquot);
diff --git a/include/linux/quotaops.h b/include/linux/quotaops.h
index 6965fe394c3b..1d3eee594cd6 100644
--- a/include/linux/quotaops.h
+++ b/include/linux/quotaops.h
@@ -46,6 +46,14 @@ void inode_reclaim_rsv_space(struct inode *inode, qsize_t number);
 void dquot_initialize(struct inode *inode);
 void dquot_drop(struct inode *inode);
 struct dquot *dqget(struct super_block *sb, struct kqid qid);
+static inline struct dquot *dqgrab(struct dquot *dquot)
+{
+        /* Make sure someone else has active reference to dquot */
+        WARN_ON_ONCE(!atomic_read(&dquot->dq_count));
+        WARN_ON_ONCE(!test_bit(DQ_ACTIVE_B, &dquot->dq_flags));
+        atomic_inc(&dquot->dq_count);
+        return dquot;
+}
 void dqput(struct dquot *dquot);
 int dquot_scan_active(struct super_block *sb,
                       int (*fn)(struct dquot *dquot, unsigned long priv),