[PATCH] more udev-016/extras/multipath

> Hello,
>
> incremental to udev-016/extras/multipath,
>
> * don't rely on the linux symlink in the udev/klibc dir since
>   udev build doesn't use it anymore. This corrects build breakage
> * remove make_dm_node fn & call. Rely on udev for this.
>
> The first patch is to be applied.
> The second is conditioned by udev dealing correctly with devmap names.
>
> For this I can suggest a CALLOUT rule like this :
> KERNEL="dm-[0-9]*", PROGRAM="/tmp/name_devmap %M %m", NAME="%k",
> SYMLINK="%c"
>
> With name_devmap like :
> #!/bin/sh
> /usr/sbin/dmsetup ls|/bin/grep "$1, $2"|/usr/bin/awk '{print $1}'
>

ok I coded the suggested tool.
it works with the following rule :
KERNEL="dm-[0-9]*", PROGRAM="/sbin/devmap_name %M %m", NAME="%k", SYMLINK="%c"

I don't know if it's right to keep this tools packaged with multipath because
it's widely more general.

Maybe Joe should merge it in the device-mapper package or provide the
functionnality through dmsetup ?

1 files changed, 60 insertions, 0 deletions

diff --git a/extras/multipath/devmap_name.c b/extras/multipath/devmap_name.c
new file mode 100644
index 0000000000..08e526e072
--- /dev/null
+++ b/extras/multipath/devmap_name.c
@@ -0,0 +1,60 @@
+#include "libdevmapper/libdevmapper.h"
+                                                                                
+#include <stdio.h>
+#include <stdlib.h>
+#include <ctype.h>
+#include <linux/kdev_t.h>
+
+static void usage(char * progname) {
+	fprintf(stderr, "usage : %s major minor\n", progname);
+	exit(1);
+}
+
+int main(int argc, char **argv)
+{
+        int r = 0;
+        struct dm_names *names;
+        unsigned next = 0;
+	int major, minor;
+                                                                                
+	/* sanity check */
+	if (argc != 3)
+		usage(argv[0]);
+
+	major = atoi(argv[1]);
+	minor = atoi(argv[2]);
+
+        struct dm_task *dmt;
+                                                                                
+        if (!(dmt = dm_task_create(DM_DEVICE_LIST)))
+                return 0;
+                                                                                
+        if (!dm_task_run(dmt))
+                goto out;
+                                                                                
+        if (!(names = dm_task_get_names(dmt)))
+                goto out;
+                                                                                
+        if (!names->dev) {
+                printf("No devices found\n");
+                goto out;
+        }
+                                                                                
+        do {
+                names = (void *) names + next;
+		if ((int) MAJOR(names->dev) == major &&
+		    (int) MINOR(names->dev) == minor) {
+	                printf("%s\n", names->name);
+			goto out;
+		}
+                next = names->next;
+        } while (next);
+                                                                                
+      /* No correspondance found */
+      r = 1;
+
+      out:
+        dm_task_destroy(dmt);
+        return r;
+}
+