o Removed the -z (suspend) option from the tools

o  New function: int lv_setup_cow_store(struct logical_volume *lv)
   This zeroes the start of the cow device.

o  Made lvcreate call above fn.

lib/activate/activate.c

@@ -15,6 +15,7 @@
 
 #include <limits.h>
 #include <linux/kdev_t.h>
+#include <fcntl.h>
 
 #define _skip(fmt, args...) log_very_verbose("Skipping: " fmt , ## args)
 
@@ -105,30 +106,20 @@ static inline int _read_only_lv(struct logical_volume *lv)
 	return (lv->status & LVM_WRITE) && (lv->vg->status & LVM_WRITE);
 }
 
-int lv_activate(struct logical_volume *lv)
+int _lv_activate_named(struct logical_volume *lv, const char *name)
 {
 	int r = 0;
 	struct dm_task *dmt;
-	char buffer[128];
 
 	if (test_mode()) {
 		_skip("Activation of '%s'.", lv->name);
 		return 0;
 	}
 
-	/*
-	 * Decide what we're going to call this device.
-	 */
-	if (!build_dm_name(buffer, sizeof(buffer), "",
-			   lv->vg->name, lv->name)) {
-		stack;
-		return 0;
-	}
-
 	/*
 	 * Create a task.
 	 */
-	if (!(dmt = setup_dm_task(buffer, DM_DEVICE_CREATE))) {
+	if (!(dmt = setup_dm_task(name, DM_DEVICE_CREATE))) {
 		stack;
 		return 0;
 	}
@@ -174,12 +165,6 @@ int lv_activate(struct logical_volume *lv)
 		goto out;
 	}
 
-	/*
-	 * Create device nodes and symbolic links.
-	 */
-	if (!fs_add_lv(lv, lv->minor))
-		stack;
-
  out:
 	dm_task_destroy(dmt);
 	log_verbose("Logical volume %s%s activated", lv->name,
@@ -187,6 +172,28 @@ int lv_activate(struct logical_volume *lv)
 	return r;
 }
 
+int lv_activate(struct logical_volume *lv)
+{
+	char buffer[128];
+
+	/*
+	 * Decide what we're going to call this device.
+	 */
+	if (!build_dm_name(buffer, sizeof(buffer), "",
+			   lv->vg->name, lv->name)) {
+		stack;
+		return 0;
+	}
+
+	if (!_lv_activate_named(lv, buffer) ||
+	    !fs_add_lv(lv, lv->minor)) {
+		stack;
+		return 0;
+	}
+
+	return 1;
+}
+
 static int _reload(const char *name, struct logical_volume *lv)
 {
 	int r = 0;
@@ -359,6 +366,52 @@ int lv_rename(const char *old_name, struct logical_volume *lv)
 	return r;
 }
 
+/*
+ * Zero the start of a cow store so the driver spots that it is a
+ * new store.
+ */
+int lv_setup_cow_store(struct logical_volume *lv)
+{
+	char buffer[128];
+	char path[PATH_MAX];
+	struct device *dev;
+
+	/*
+	 * Decide what we're going to call this device.
+	 */
+	if (!build_dm_name(buffer, sizeof(buffer), "cow_init",
+			   lv->vg->name, lv->name)) {
+		stack;
+		return 0;
+	}
+
+	if (!_lv_activate_named(lv, buffer)) {
+		log_err("Unable to activate cow store logical volume.");
+		return 0;
+	}
+
+	/* FIXME: hard coded dir */
+	if (lvm_snprintf(path, sizeof(path), "/dev/device-mapper/%s",
+			 buffer) < 0) {
+		log_error("Name too long - device not zeroed (%s)",
+			  lv->name);
+		return 0;
+	}
+
+	if (!(dev = dev_cache_get(path, NULL))) {
+		log_error("\"%s\" not found: device not zeroed", path);
+		return 0;
+	}
+
+	if (!(dev_open(dev, O_WRONLY)))
+		return 0;
+
+	dev_zero(dev, 0, 4096);
+	dev_close(dev);
+
+	return 1;
+}
+
 
 int activate_lvs_in_vg(struct volume_group *vg)
 {

lib/activate/activate.h

@@ -34,6 +34,11 @@ int lv_deactivate(struct logical_volume *lv);
 int lv_suspend(struct logical_volume *lv);
 int lv_rename(const char *old_name, struct logical_volume *lv);
 
+/*
+ * Snapshot volume need kernel specific initialisation.
+ */
+int lv_setup_cow_store(struct logical_volume *lv);
+
 /*
  * Return number of LVs in the VG that are active.
  */

tools/lvcreate.c

@@ -206,8 +206,7 @@ static int _read_params(struct lvcreate_params *lp, struct cmd_context *cmd,
 	/*
 	 * Should we zero the lv.
 	 */
-	lp->zero = strcmp(arg_str_value(cmd, zero_ARG, "y"), "n") ||
-		arg_count(cmd, snapshot_ARG);
+	lp->zero = strcmp(arg_str_value(cmd, zero_ARG, "y"), "n");
 
 	/*
 	 * Contiguous ?
@@ -376,16 +375,15 @@ static int _lvcreate(struct cmd_context *cmd, struct lvcreate_params *lp,
 		return 0;
 
 	backup(vg);
-
 	log_print("Logical volume \"%s\" created", lv->name);
 
-	if (!lv_activate(lv))
-		return 0;
-
 	*plv = lv;
 	return 1;
 }
 
+/*
+ * Non-snapshot volumes may be zeroed to remove old filesystems.
+ */
 static int _zero(struct cmd_context *cmd, struct logical_volume *lv)
 {
 	struct device *dev;
@@ -445,14 +443,24 @@ int lvcreate(struct cmd_context *cmd, int argc, char **argv)
 		goto out;
 	}
 
-	if (!lp.zero) {
-		log_print("WARNING: \"%s\" not zeroed", lv->name);
-
-	} else if (!_zero(cmd, lv)) {
+	if (!lp.snapshot && !lv_setup_cow_store(lv)) {
 		stack;
 		goto out;
 	}
 
+	if (!lv_activate(lv))
+		goto out;
+
+	if (!lp.snapshot) {
+		if (!lp.zero)
+			log_print("WARNING: \"%s\" not zeroed", lv->name);
+
+		else if (!_zero(cmd, lv)) {
+			stack;
+			goto out;
+		}
+	}
+
 	/*
 	 * FIXME: as a sanity check we could try reading the
 	 * last block of the device ?

tools/lvm.c

@@ -342,7 +342,7 @@ char yes_no_prompt(const char *prompt, ...)
 static void register_commands()
 {
 #define xx(a, b, c...) register_command(# a, a, b, ## c, \
-                                        debug_ARG, help_ARG, suspend_ARG, \
+                                        debug_ARG, help_ARG, \
                                         version_ARG, verbose_ARG, \
 					quiet_ARG, -1);
 #include "commands.h"