Btrfs: put back delayed refs that are too new

When processing a delayed ref, first check if there are still old refs in
the process of being added. If so, put this ref back to the tree. To avoid
looping on this ref, choose a newer one in the next loop.
btrfs_find_ref_cluster has to take care of that.

Signed-off-by: Arne Jansen <sensille@gmx.net>
Signed-off-by: Jan Schmidt <list.btrfs@jan-o-sch.net>

1 files changed, 22 insertions, 5 deletions

diff --git a/fs/btrfs/extent-tree.c b/fs/btrfs/extent-tree.c
index dc8b9a834596..bbcca12fbbba 100644
--- a/fs/btrfs/extent-tree.c
+++ b/fs/btrfs/extent-tree.c
@@ -2237,6 +2237,28 @@ static noinline int run_clustered_refs(struct btrfs_trans_handle *trans,
                 }
 
                 /*
+                 * locked_ref is the head node, so we have to go one
+                 * node back for any delayed ref updates
+                 */
+                ref = select_delayed_ref(locked_ref);
+
+                if (ref && ref->seq &&
+                    btrfs_check_delayed_seq(delayed_refs, ref->seq)) {
+                        /*
+                         * there are still refs with lower seq numbers in the
+                         * process of being added. Don't run this ref yet.
+                         */
+                        list_del_init(&locked_ref->cluster);
+                        mutex_unlock(&locked_ref->mutex);
+                        locked_ref = NULL;
+                        delayed_refs->num_heads_ready++;
+                        spin_unlock(&delayed_refs->lock);
+                        cond_resched();
+                        spin_lock(&delayed_refs->lock);
+                        continue;
+                }
+
+                /*
                  * record the must insert reserved flag before we
                  * drop the spin lock.
                  */
@@ -2246,11 +2268,6 @@ static noinline int run_clustered_refs(struct btrfs_trans_handle *trans,
                 extent_op = locked_ref->extent_op;
                 locked_ref->extent_op = NULL;
 
-                /*
-                 * locked_ref is the head node, so we have to go one
-                 * node back for any delayed ref updates
-                 */
-                ref = select_delayed_ref(locked_ref);
                 if (!ref) {
                         /* All delayed refs have been processed, Go ahead
                          * and send the head node to run_one_delayed_ref,