[lvm-devel][PATCH 5/5] Udev integration: add lvmsplit command for dmsetup

Thu Apr 23 13:07:39 UTC 2009

This one adds support for lvmsplit command in dmsetup so we can split
given DM name into its VG/LV/LAYER parts. This way we don't have to
issue an ioctl when we already have a name in udev rule and we
want this name to be splitted, nothing else.

The implementation is very simple and not perfect though, but it does
what it is supposed to do. I also hope we move this code to liblvm
sometime in the future, together with the first patch ("add LVM fields
support for dmsetup"). But we keep it here for now.

Peter

diff --git a/tools/dmsetup.c b/tools/dmsetup.c
index b1121f8..eb156a4 100644
--- a/tools/dmsetup.c
+++ b/tools/dmsetup.c
@@ -745,6 +745,24 @@ static int _udevnotify(int argc, char **argv, void *data __attribute((unused)))
 	return dm_notification_sem_dec(cookie);
 }
 
+static int _lvmsplit(int argc, char **argv, void *data __attribute((unused)))
+{
+	int r = 1;
+
+	struct dmsetup_report_obj obj;
+
+	obj.task = NULL;
+	obj.info = NULL;
+	obj.deps_task = NULL;
+	obj.tree_node = NULL;
+	obj.split_name = _get_split_name("LVM-", argv[1]);
+
+	r = dm_report_object(_report, &obj);
+	_destroy_split_name(obj.split_name);
+
+	return r;
+}
+
 static int _version(int argc __attribute((unused)), char **argv __attribute((unused)), void *data __attribute((unused)))
 {
 	char version[80];
@@ -2145,6 +2163,7 @@ FIELD_O(NAME, dm_split_name, STR, "LVLayer", lv_layer, 7, dm_lv_layer_name, "lv_
 #undef FIELD_F
 
 static const char *default_report_options = "name,major,minor,attr,open,segments,events,uuid";
+static const char *lvmsplit_report_options = "vg_name,lv_name,lv_layer";
 
 static int _report_init(struct command *c)
 {
@@ -2157,6 +2176,9 @@ static int _report_init(struct command *c)
 	size_t len = 0;
 	int r = 0;
 
+	if (!strcmp(c->name, "lvmsplit"))
+		options = (char *) lvmsplit_report_options;
+
 	/* emulate old dmsetup behaviour */
 	if (_switches[NOHEADINGS_ARG]) {
 		separator = ":";
@@ -2294,6 +2316,7 @@ static struct command _commands[] = {
 	{"wait", "<device> [<event_nr>]", 0, 2, _wait},
 	{"mknodes", "[<device>]", 0, 1, _mknodes},
 	{"udevnotify", "<cookie>", 1, 1, _udevnotify},
+	{"lvmsplit", "<dev_name>", 1, 1, _lvmsplit},
 	{"targets", "", 0, 0, _targets},
 	{"version", "", 0, 0, _version},
 	{"setgeometry", "<device> <cyl> <head> <sect> <start>", 5, 5, _setgeometry},
@@ -2914,6 +2937,9 @@ int main(int argc, char **argv)
 		goto out;
 	}
 
+	if (!_switches[COLS_ARG] && !strcmp(c->name, "lvmsplit"))
+		_switches[COLS_ARG]++;
+
 	if (_switches[COLS_ARG] && !_report_init(c))
 		goto out;
 


