From 7e35dfff3d556e0157fe5e2ed18b6123ebc4ba34 Mon Sep 17 00:00:00 2001
From: Zdenek Kabelac <zkabelac@redhat.com>
Date: Fri, 2 Mar 2012 17:31:21 +0000
Subject: [PATCH] Added dm_tree_node_set_callback() for preload and
 deactivation hooks

Run users hook after preload for the node is finished,
or after the node has been deactivated.
---
 WHATS_NEW_DM          |  1 +
 libdm/libdevmapper.h  | 14 ++++++++++++++
 libdm/libdm-deptree.c | 27 ++++++++++++++++++++++++++-
 3 files changed, 41 insertions(+), 1 deletion(-)

diff --git a/WHATS_NEW_DM b/WHATS_NEW_DM
index c3e8e1594..f8e7e7bdf 100644
--- a/WHATS_NEW_DM
+++ b/WHATS_NEW_DM
@@ -1,5 +1,6 @@
 Version 1.02.73 - 
 ====================================
+  Added dm_tree_node_set_callback() for preload and deactivation hooks.
   Drop unsupported TRIM message for thin pool.
   Improve logging for fifo startup in dmeventd.
   Add few pointer validation in dmsetup.
diff --git a/libdm/libdevmapper.h b/libdm/libdevmapper.h
index dfbadaa27..7df4db8a6 100644
--- a/libdm/libdevmapper.h
+++ b/libdm/libdevmapper.h
@@ -688,6 +688,20 @@ void dm_tree_node_set_read_ahead(struct dm_tree_node *dnode,
 				 uint32_t read_ahead,
 				 uint32_t read_ahead_flags);
 
+/*
+ * Set node callback hook before de/activation.
+ * Callback is called before 'activation' of node for activation tree,
+ * or 'deactivation' of node for deactivation tree.
+ */
+typedef enum {
+	DM_NODE_CALLBACK_PRELOADED,   /* Node has preload deps */
+	DM_NODE_CALLBACK_DEACTIVATED, /* Node is deactivated */
+} dm_node_callback_t;
+typedef int (*dm_node_callback_fn) (struct dm_tree_node *node,
+				    dm_node_callback_t type, void *cb_data);
+void dm_tree_node_set_callback(struct dm_tree_node *node,
+			       dm_node_callback_fn cb, void *cb_data);
+
 void dm_tree_set_cookie(struct dm_tree_node *node, uint32_t cookie);
 uint32_t dm_tree_get_cookie(struct dm_tree_node *node);
 
diff --git a/libdm/libdm-deptree.c b/libdm/libdm-deptree.c
index e80db2fee..582a14a66 100644
--- a/libdm/libdm-deptree.c
+++ b/libdm/libdm-deptree.c
@@ -263,6 +263,10 @@ struct dm_tree_node {
 	 * Note: only direct child is allowed
 	 */
 	struct dm_tree_node *presuspend_node;
+
+	/* Callback */
+	dm_node_callback_fn callback;
+	void *callback_data;
 };
 
 struct dm_tree {
@@ -1588,6 +1592,14 @@ static int _dm_tree_deactivate_children(struct dm_tree_node *dnode,
 		} else if (info.suspended)
 			dec_suspended();
 
+		if (child->callback &&
+		    !child->callback(child, DM_NODE_CALLBACK_DEACTIVATED,
+				     child->callback_data)) {
+			r = 0;
+			// FIXME: break tree shutdown or continue?
+			// hmm what about _node_clear_table()?
+		}
+
 		if (dm_tree_node_num_children(child, 0)) {
 			if (!_dm_tree_deactivate_children(child, uuid_prefix, uuid_prefix_len, level + 1))
 				return_0;
@@ -2445,10 +2457,16 @@ int dm_tree_preload_children(struct dm_tree_node *dnode,
 			update_devs_flag = 1;
 	}
 
-	if (update_devs_flag) {
+	if (update_devs_flag ||
+	    (!dnode->info.exists && dnode->callback)) {
 		if (!dm_udev_wait(dm_tree_get_cookie(dnode)))
 			stack;
 		dm_tree_set_cookie(dnode, 0);
+
+		if (!dnode->info.exists && dnode->callback &&
+		    !dnode->callback(child, DM_NODE_CALLBACK_PRELOADED,
+				     dnode->callback_data))
+			return_0;
 	}
 
 	return r;
@@ -3245,3 +3263,10 @@ int dm_tree_node_add_null_area(struct dm_tree_node *node, uint64_t offset)
 
 	return 1;
 }
+
+void dm_tree_node_set_callback(struct dm_tree_node *dnode,
+			       dm_node_callback_fn cb, void *data)
+{
+	dnode->callback = cb;
+	dnode->callback_data = data;
+}
-- 
2.43.5