btrfs: locking: remove all the blocking helpers

Now that we're using a rw_semaphore we no longer need to indicate if a
lock is blocking or not, nor do we need to flip the entire path from
blocking to spinning.  Remove these helpers and all the places they are
called.

Signed-off-by: Josef Bacik <josef@toxicpanda.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
diff --git a/fs/btrfs/ref-verify.c b/fs/btrfs/ref-verify.c
index 14b0c0d..488bc3d 100644
--- a/fs/btrfs/ref-verify.c
+++ b/fs/btrfs/ref-verify.c
@@ -575,10 +575,9 @@ static int walk_down_tree(struct btrfs_root *root, struct btrfs_path *path,
 				return -EIO;
 			}
 			btrfs_tree_read_lock(eb);
-			btrfs_set_lock_blocking_read(eb);
 			path->nodes[level-1] = eb;
 			path->slots[level-1] = 0;
-			path->locks[level-1] = BTRFS_READ_LOCK_BLOCKING;
+			path->locks[level-1] = BTRFS_READ_LOCK;
 		} else {
 			ret = process_leaf(root, path, bytenr, num_bytes);
 			if (ret)
@@ -1000,11 +999,10 @@ int btrfs_build_ref_tree(struct btrfs_fs_info *fs_info)
 		return -ENOMEM;
 
 	eb = btrfs_read_lock_root_node(fs_info->extent_root);
-	btrfs_set_lock_blocking_read(eb);
 	level = btrfs_header_level(eb);
 	path->nodes[level] = eb;
 	path->slots[level] = 0;
-	path->locks[level] = BTRFS_READ_LOCK_BLOCKING;
+	path->locks[level] = BTRFS_READ_LOCK;
 
 	while (1) {
 		/*