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-rw-r--r--fs/btrfs/extent-tree.c67
1 files changed, 67 insertions, 0 deletions
diff --git a/fs/btrfs/extent-tree.c b/fs/btrfs/extent-tree.c
index 9b5da2b..8471c79 100644
--- a/fs/btrfs/extent-tree.c
+++ b/fs/btrfs/extent-tree.c
@@ -1021,6 +1021,7 @@ again:
if (!locked_ref && count == 0)
break;
+ cond_resched();
spin_lock(&delayed_refs->lock);
}
if (run_all) {
@@ -1045,6 +1046,7 @@ again:
mutex_unlock(&head->mutex);
btrfs_put_delayed_ref(ref);
+ cond_resched();
goto again;
}
node = rb_next(node);
@@ -2361,6 +2363,68 @@ static int __btrfs_free_extent(struct btrfs_trans_handle *trans,
owner_objectid, pin, pin == 0, refs_to_drop);
}
+/*
+ * when we free an extent, it is possible (and likely) that we free the last
+ * delayed ref for that extent as well. This searches the delayed ref tree for
+ * a given extent, and if there are no other delayed refs to be processed, it
+ * removes it from the tree.
+ */
+static noinline int check_ref_cleanup(struct btrfs_trans_handle *trans,
+ struct btrfs_root *root, u64 bytenr)
+{
+ struct btrfs_delayed_ref_head *head;
+ struct btrfs_delayed_ref_root *delayed_refs;
+ struct btrfs_delayed_ref_node *ref;
+ struct rb_node *node;
+ int ret;
+
+ delayed_refs = &trans->transaction->delayed_refs;
+ spin_lock(&delayed_refs->lock);
+ head = btrfs_find_delayed_ref_head(trans, bytenr);
+ if (!head)
+ goto out;
+
+ node = rb_prev(&head->node.rb_node);
+ if (!node)
+ goto out;
+
+ ref = rb_entry(node, struct btrfs_delayed_ref_node, rb_node);
+
+ /* there are still entries for this ref, we can't drop it */
+ if (ref->bytenr == bytenr)
+ goto out;
+
+ /*
+ * waiting for the lock here would deadlock. If someone else has it
+ * locked they are already in the process of dropping it anyway
+ */
+ if (!mutex_trylock(&head->mutex))
+ goto out;
+
+ /*
+ * at this point we have a head with no other entries. Go
+ * ahead and process it.
+ */
+ head->node.in_tree = 0;
+ rb_erase(&head->node.rb_node, &delayed_refs->root);
+ delayed_refs->num_entries--;
+
+ /*
+ * we don't take a ref on the node because we're removing it from the
+ * tree, so we just steal the ref the tree was holding.
+ */
+ spin_unlock(&delayed_refs->lock);
+
+ ret = run_one_delayed_ref(trans, root->fs_info->tree_root,
+ &head->node, head->must_insert_reserved);
+ BUG_ON(ret);
+ btrfs_put_delayed_ref(&head->node);
+ return 0;
+out:
+ spin_unlock(&delayed_refs->lock);
+ return 0;
+}
+
int btrfs_free_extent(struct btrfs_trans_handle *trans,
struct btrfs_root *root,
u64 bytenr, u64 num_bytes, u64 parent,
@@ -2388,6 +2452,9 @@ int btrfs_free_extent(struct btrfs_trans_handle *trans,
root_objectid, ref_generation,
owner_objectid,
BTRFS_DROP_DELAYED_REF, 1);
+ BUG_ON(ret);
+ ret = check_ref_cleanup(trans, root, bytenr);
+ BUG_ON(ret);
}
return ret;
}
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