1 files changed, 38 insertions, 20 deletions

diff --git a/fs/btrfs/ref-cache.c b/fs/btrfs/ref-cache.c
index 272b9890c982..c5809988c875 100644
--- a/fs/btrfs/ref-cache.c
+++ b/fs/btrfs/ref-cache.c
@@ -78,7 +78,6 @@ static struct rb_node *tree_insert(struct rb_root *root, u64 bytenr,
         }
 
         entry = rb_entry(node, struct btrfs_leaf_ref, rb_node);
-        entry->in_tree = 1;
         rb_link_node(node, parent, p);
         rb_insert_color(node, root);
         return NULL;
@@ -103,23 +102,29 @@ static struct rb_node *tree_search(struct rb_root *root, u64 bytenr)
         return NULL;
 }
 
-int btrfs_remove_leaf_refs(struct btrfs_root *root, u64 max_root_gen)
+int btrfs_remove_leaf_refs(struct btrfs_root *root, u64 max_root_gen,
+                           int shared)
 {
         struct btrfs_leaf_ref *ref = NULL;
         struct btrfs_leaf_ref_tree *tree = root->ref_tree;
 
+        if (shared)
+                tree = &root->fs_info->shared_ref_tree;
         if (!tree)
                 return 0;
 
         spin_lock(&tree->lock);
         while(!list_empty(&tree->list)) {
                 ref = list_entry(tree->list.next, struct btrfs_leaf_ref, list);
-                BUG_ON(!ref->in_tree);
+                BUG_ON(ref->tree != tree);
                 if (ref->root_gen > max_root_gen)
                         break;
+                if (!xchg(&ref->in_tree, 0)) {
+                        cond_resched_lock(&tree->lock);
+                        continue;
+                }
 
                 rb_erase(&ref->rb_node, &tree->root);
-                ref->in_tree = 0;
                 list_del_init(&ref->list);
 
                 spin_unlock(&tree->lock);
@@ -137,32 +142,43 @@ struct btrfs_leaf_ref *btrfs_lookup_leaf_ref(struct btrfs_root *root,
         struct rb_node *rb;
         struct btrfs_leaf_ref *ref = NULL;
         struct btrfs_leaf_ref_tree *tree = root->ref_tree;
-
-        if (!tree)
-                return NULL;
-
-        spin_lock(&tree->lock);
-        rb = tree_search(&tree->root, bytenr);
-        if (rb)
-                ref = rb_entry(rb, struct btrfs_leaf_ref, rb_node);
-        if (ref)
-                atomic_inc(&ref->usage);
-        spin_unlock(&tree->lock);
-        return ref;
+again:
+        if (tree) {
+                spin_lock(&tree->lock);
+                rb = tree_search(&tree->root, bytenr);
+                if (rb)
+                        ref = rb_entry(rb, struct btrfs_leaf_ref, rb_node);
+                if (ref)
+                        atomic_inc(&ref->usage);
+                spin_unlock(&tree->lock);
+                if (ref)
+                        return ref;
+        }
+        if (tree != &root->fs_info->shared_ref_tree) {
+                tree = &root->fs_info->shared_ref_tree;
+                goto again;
+        }
+        return NULL;
 }
 
-int btrfs_add_leaf_ref(struct btrfs_root *root, struct btrfs_leaf_ref *ref)
+int btrfs_add_leaf_ref(struct btrfs_root *root, struct btrfs_leaf_ref *ref,
+                       int shared)
 {
         int ret = 0;
         struct rb_node *rb;
         struct btrfs_leaf_ref_tree *tree = root->ref_tree;
 
+        if (shared)
+                tree = &root->fs_info->shared_ref_tree;
+
         spin_lock(&tree->lock);
         rb = tree_insert(&tree->root, ref->bytenr, &ref->rb_node);
         if (rb) {
                 ret = -EEXIST;
         } else {
                 atomic_inc(&ref->usage);
+                ref->tree = tree;
+                ref->in_tree = 1;
                 list_add_tail(&ref->list, &tree->list);
         }
         spin_unlock(&tree->lock);
@@ -171,13 +187,15 @@ int btrfs_add_leaf_ref(struct btrfs_root *root, struct btrfs_leaf_ref *ref)
 
 int btrfs_remove_leaf_ref(struct btrfs_root *root, struct btrfs_leaf_ref *ref)
 {
-        struct btrfs_leaf_ref_tree *tree = root->ref_tree;
+        struct btrfs_leaf_ref_tree *tree;
+
+        if (!xchg(&ref->in_tree, 0))
+                return 0;
 
-        BUG_ON(!ref->in_tree);
+        tree = ref->tree;
         spin_lock(&tree->lock);
 
         rb_erase(&ref->rb_node, &tree->root);
-        ref->in_tree = 0;
         list_del_init(&ref->list);
 
         spin_unlock(&tree->lock);