From 43118cc6b993e18a8c8b6db4004dd82cc96fa97b Mon Sep 17 00:00:00 2001
From: Alasdair Kergon <agk@redhat.com>
Date: Tue, 22 Nov 2005 18:43:12 +0000
Subject: [PATCH] Drop leading zeros from dm_format_dev. Suppress attempt to
 reload identical table.

---
 WHATS_NEW                 |  2 ++
 lib/.exported_symbols     |  1 +
 lib/ioctl/libdm-iface.c   | 76 ++++++++++++++++++++++++++++++++++++++-
 lib/ioctl/libdm-targets.h |  1 +
 lib/libdevmapper.h        |  1 +
 lib/libdm-deptree.c       | 10 ++++--
 6 files changed, 88 insertions(+), 3 deletions(-)

diff --git a/WHATS_NEW b/WHATS_NEW
index 3de28a7..f05d270 100644
--- a/WHATS_NEW
+++ b/WHATS_NEW
@@ -1,5 +1,7 @@
 Version 1.02.01 - 
 =============================
+  Drop leading zeros from dm_format_dev.
+  Suppress attempt to reload identical table.
   Additional LVM- prefix matching for transitional period.
 
 Version 1.02.00 - 10 Nov 2005
diff --git a/lib/.exported_symbols b/lib/.exported_symbols
index 23c3f70..898c06e 100644
--- a/lib/.exported_symbols
+++ b/lib/.exported_symbols
@@ -22,6 +22,7 @@ dm_task_set_major
 dm_task_set_minor
 dm_task_set_sector
 dm_task_set_message
+dm_task_suppress_identical_reload
 dm_task_add_target
 dm_task_no_open_count
 dm_task_skip_lockfs
diff --git a/lib/ioctl/libdm-iface.c b/lib/ioctl/libdm-iface.c
index c915333..3f2e592 100644
--- a/lib/ioctl/libdm-iface.c
+++ b/lib/ioctl/libdm-iface.c
@@ -875,7 +875,7 @@ int dm_format_dev(char *buf, int bufsize, uint32_t dev_major,
 	if (bufsize < 8)
 		return 0;
 
-	r = snprintf(buf, bufsize, "%03u:%03u", dev_major, dev_minor);
+	r = snprintf(buf, bufsize, "%u:%u", dev_major, dev_minor);
 	if (r < 0 || r > bufsize - 1)
 		return 0;
 
@@ -966,6 +966,12 @@ int dm_task_set_ro(struct dm_task *dmt)
 	return 1;
 }
 
+int dm_task_suppress_identical_reload(struct dm_task *dmt)
+{
+	dmt->suppress_identical_reload = 1;
+	return 1;
+}
+
 int dm_task_set_newname(struct dm_task *dmt, const char *newname)
 {
 	if (!(dmt->newname = dm_strdup(newname))) {
@@ -1342,6 +1348,71 @@ static int _create_and_load_v4(struct dm_task *dmt)
 	return r;
 }
 
+static int _reload_with_suppression_v4(struct dm_task *dmt)
+{
+	struct dm_task *task;
+	struct target *t1, *t2;
+	int matches = 1;
+	int r;
+
+	/* New task to get existing table information */
+	if (!(task = dm_task_create(DM_DEVICE_TABLE))) {
+		log_error("Failed to create device-mapper task struct");
+		return 0;
+	}
+
+	/* Copy across relevant fields */
+	if (dmt->dev_name && !dm_task_set_name(task, dmt->dev_name)) {
+		dm_task_destroy(task);
+		return 0;
+	}
+
+	if (dmt->uuid && !dm_task_set_uuid(task, dmt->uuid)) {
+		dm_task_destroy(task);
+		return 0;
+	}
+
+	task->major = dmt->major;
+	task->minor = dmt->minor;
+
+	r = dm_task_run(task);
+
+	if (!r) {
+		dm_task_destroy(task);
+		return r;
+	}
+
+	t1 = dmt->head;
+	t2 = task->head;
+
+	while (t1 && t2) {
+		if ((t1->start != t2->start) ||
+		    (t1->length != t2->length) ||
+		    (strcmp(t1->type, t2->type)) ||
+		    (strcmp(t1->params, t2->params))) {
+			matches = 0;
+			break;
+		}
+		t1 = t1->next;
+		t2 = t2->next;
+	}
+	
+	if (matches && !t1 && !t2) {
+		dmt->dmi.v4 = task->dmi.v4;
+		task->dmi.v4 = NULL;
+		dm_task_destroy(task);
+		return 1;
+	}
+
+	dm_task_destroy(task);
+
+	/* Now do the original reload */
+	dmt->suppress_identical_reload = 0;
+	r = dm_task_run(dmt);
+
+	return r;
+}
+
 static struct dm_ioctl *_do_dm_ioctl(struct dm_task *dmt, unsigned command,
 				     unsigned repeat_count)
 {
@@ -1426,6 +1497,9 @@ int dm_task_run(struct dm_task *dmt)
 	    !dmt->uuid && dmt->major <= 0)
 		return _mknodes_v4(dmt);
 
+	if ((dmt->type == DM_DEVICE_RELOAD) && dmt->suppress_identical_reload)
+		return _reload_with_suppression_v4(dmt);
+
 	if (!_open_control())
 		return 0;
 
diff --git a/lib/ioctl/libdm-targets.h b/lib/ioctl/libdm-targets.h
index ce3ab82..4eea595 100644
--- a/lib/ioctl/libdm-targets.h
+++ b/lib/ioctl/libdm-targets.h
@@ -53,6 +53,7 @@ struct dm_task {
 	uint64_t sector;
 	int no_open_count;
 	int skip_lockfs;
+	int suppress_identical_reload;
 
 	char *uuid;
 };
diff --git a/lib/libdevmapper.h b/lib/libdevmapper.h
index a6c3db2..1a7710c 100644
--- a/lib/libdevmapper.h
+++ b/lib/libdevmapper.h
@@ -145,6 +145,7 @@ int dm_task_set_message(struct dm_task *dmt, const char *message);
 int dm_task_set_sector(struct dm_task *dmt, uint64_t sector);
 int dm_task_no_open_count(struct dm_task *dmt);
 int dm_task_skip_lockfs(struct dm_task *dmt);
+int dm_task_suppress_identical_reload(struct dm_task *dmt);
 
 /*
  * Use these to prepare for a create or reload.
diff --git a/lib/libdm-deptree.c b/lib/libdm-deptree.c
index 30a1e6d..d60f860 100644
--- a/lib/libdm-deptree.c
+++ b/lib/libdm-deptree.c
@@ -1353,8 +1353,15 @@ static int _load_node(struct dm_tree_node *dnode)
 		if (!_emit_segment(dmt, seg, &seg_start))
 			goto_out;
 
-	if ((r = dm_task_run(dmt)))
+	if (!dm_task_suppress_identical_reload(dmt))
+		log_error("Failed to suppress reload of identical tables.");
+
+	if ((r = dm_task_run(dmt))) {
 		r = dm_task_get_info(dmt, &dnode->info);
+		if (r && !dnode->info.inactive_table)
+			log_verbose("Suppressed %s identical table reload.",
+				    dnode->name);
+	}
 
 	dnode->props.segment_count = 0;
 
@@ -1362,7 +1369,6 @@ out:
 	dm_task_destroy(dmt);
 
 	return r;
-
 }
 
 int dm_tree_preload_children(struct dm_tree_node *dnode,
-- 
2.43.5