1 files changed, 8 insertions, 3 deletions

diff --git a/fs/ext4/mballoc.c b/fs/ext4/mballoc.c
index 4d113efa024c..04766d9a29cd 100644
--- a/fs/ext4/mballoc.c
+++ b/fs/ext4/mballoc.c
@@ -3442,6 +3442,9 @@ static void ext4_mb_pa_callback(struct rcu_head *head)
 {
         struct ext4_prealloc_space *pa;
         pa = container_of(head, struct ext4_prealloc_space, u.pa_rcu);
+
+        BUG_ON(atomic_read(&pa->pa_count));
+        BUG_ON(pa->pa_deleted == 0);
         kmem_cache_free(ext4_pspace_cachep, pa);
 }
 
@@ -3455,11 +3458,13 @@ static void ext4_mb_put_pa(struct ext4_allocation_context *ac,
         ext4_group_t grp;
         ext4_fsblk_t grp_blk;
 
-        if (!atomic_dec_and_test(&pa->pa_count) || pa->pa_free != 0)
-                return;
-
         /* in this short window concurrent discard can set pa_deleted */
         spin_lock(&pa->pa_lock);
+        if (!atomic_dec_and_test(&pa->pa_count) || pa->pa_free != 0) {
+                spin_unlock(&pa->pa_lock);
+                return;
+        }
+
         if (pa->pa_deleted == 1) {
                 spin_unlock(&pa->pa_lock);
                 return;