[dm-devel] [Patch] kpartx to accept device map name

["Jun'ichi Nomura" <j-nomura ce jp nec com>]

Hello Christophe,

Attached patch adds '-m' option which makes kpartx
to accept device map name.

Using with the cvs version of libdevmapper or with the
patch suggested by Kiyoshi Ueda today, we don't need
to depend on asynchronous nature of hotplug when it's
not necessary.

For example, we can do this for initialization:
  multipath
  dmsetup info -c --noheadings -o name | xargs -l1 kpartx -a -m
otherwise we had to insert adhoc length of sleep to wait for
the completion of hotplug events.

Please consider to apply.

Thanks,
Jun'ichi Nomura

Index: kpartx/kpartx.c
===================================================================
--- e5bb12309df918f41b63a339fdc936f77241d332/kpartx/kpartx.c  (mode:100644)
+++ uncommitted/kpartx/kpartx.c  (mode:100644)
@@ -70,7 +70,7 @@
 	addpts("unixware", read_unixware_pt);
 }
 
-static char short_opts[] = "ladgvnp:t:";
+static char short_opts[] = "ladgvnp:t:m";
 
 /* Used in gpt.c */
 int force_gpt=0;
@@ -183,6 +183,7 @@
 	char * delim = NULL;
 	int loopro = 0;
 	int hotplug = 0;
+	int use_mapname = 0;
 	struct stat buf;
 
 	initpts();
@@ -245,12 +246,16 @@
 		case 'd':
 			what = DELETE;
 			break;
+		case 'm':
+			use_mapname = 1;
+			break;
 		default:
 			usage();
 			exit(1);
 	}
 
-	if (dm_prereq(DM_TARGET, 0, 0, 0) && (what == ADD || what == DELETE)) {
+	if (dm_prereq(DM_TARGET, 0, 0, 0)
+	    && (what == ADD || what == DELETE || use_mapname)) {
 		fprintf(stderr, "device mapper prerequisites not met\n"); 
 		exit(1);
 	}
@@ -267,6 +272,21 @@
 		exit(1);
 	}
 
+	if (use_mapname) {
+		int len;
+		char *realdev, *dmdir;
+
+		dmdir = dm_dir();
+		len = strlen(dmdir) + strlen(device) + 2;
+		realdev = malloc(sizeof(char) * len);
+		if (!realdev) {
+			printf("failed to alloc memory\n");
+			exit(1);
+		}
+		snprintf(realdev, len, "%s/%s", dmdir, device);
+		diskdevice = device = realdev;
+	}
+
 	if (stat(device, &buf)) {
 		printf("failed to stat() %s\n", device);
 		exit (1);