1 files changed, 13 insertions, 0 deletions

diff --git a/fs/btrfs/extent-tree.c b/fs/btrfs/extent-tree.c
index 1c2bd1723e40..171312d51799 100644
--- a/fs/btrfs/extent-tree.c
+++ b/fs/btrfs/extent-tree.c
@@ -2296,9 +2296,22 @@ static int run_one_delayed_ref(struct btrfs_trans_handle *trans,
 static inline struct btrfs_delayed_ref_node *
 select_delayed_ref(struct btrfs_delayed_ref_head *head)
 {
+        struct btrfs_delayed_ref_node *ref;
+
         if (list_empty(&head->ref_list))
                 return NULL;
 
+        /*
+         * Select a delayed ref of type BTRFS_ADD_DELAYED_REF first.
+         * This is to prevent a ref count from going down to zero, which deletes
+         * the extent item from the extent tree, when there still are references
+         * to add, which would fail because they would not find the extent item.
+         */
+        list_for_each_entry(ref, &head->ref_list, list) {
+                if (ref->action == BTRFS_ADD_DELAYED_REF)
+                        return ref;
+        }
+
         return list_entry(head->ref_list.next, struct btrfs_delayed_ref_node,
                           list);
 }