From bc17158dcc9eac6eed4b84d1f41d1dcaa108cb9b Mon Sep 17 00:00:00 2001
From: NeilBrown <neilb@suse.de>
Date: Thu, 1 Aug 2013 14:32:04 +1000
Subject: [PATCH] Introduce devid2kname - slightly different to devid2devnm.

The purpose od devid2devnm is to return a kernel name of an
md device, whether that device is a whole device or a partition,
we want the whole device.  md4, never md4p2.

In one place I was using devid2devnm where I really wanted the
partition if there was one ... and wasn't really interested in it
being an md device.
So introduce a new 'devid2kname' for that case.

Signed-off-by: NeilBrown <neilb@suse.de>
---
 lib.c   | 26 ++++++++++++++++++++++++++
 mdadm.h |  1 +
 sysfs.c |  2 +-
 3 files changed, 28 insertions(+), 1 deletion(-)

diff --git a/lib.c b/lib.c
index 8285f34..6808f62 100644
--- a/lib.c
+++ b/lib.c
@@ -58,6 +58,32 @@ static int mdp_major = -1;
 	return mdp_major;
 }
 
+char *devid2kname(int devid)
+{
+	char path[30];
+	char link[200];
+	static char devnm[32];
+	char *cp;
+	int n;
+
+	/* Look at the
+	 * /sys/dev/block/%d:%d link which must look like
+	 * and take the last component.
+	 */
+	sprintf(path, "/sys/dev/block/%d:%d", major(devid),
+		minor(devid));
+	n = readlink(path, link, sizeof(link)-1);
+	if (n > 0) {
+		link[n] = 0;
+		cp = strrchr(link, '/');
+		if (cp) {
+			strcpy(devnm, cp+1);
+			return devnm;
+		}
+	}
+	return NULL;
+}
+
 char *devid2devnm(int devid)
 {
 	char path[30];
diff --git a/mdadm.h b/mdadm.h
index 5463bfb..c5d9c30 100644
--- a/mdadm.h
+++ b/mdadm.h
@@ -1349,6 +1349,7 @@ extern void print_r10_layout(int layout);
 extern char *find_free_devnm(int use_partitions);
 
 extern void put_md_name(char *name);
+extern char *devid2kname(int devid);
 extern char *devid2devnm(int devid);
 extern int devnm2devid(char *devnm);
 extern char *get_md_name(char *devnm);
diff --git a/sysfs.c b/sysfs.c
index 13558c5..9a1d856 100644
--- a/sysfs.c
+++ b/sysfs.c
@@ -682,7 +682,7 @@ int sysfs_add_disk(struct mdinfo *sra, struct mdinfo *sd, int resume)
 		return rv;
 
 	memset(nm, 0, sizeof(nm));
-	dname = devid2devnm(makedev(sd->disk.major, sd->disk.minor));
+	dname = devid2kname(makedev(sd->disk.major, sd->disk.minor));
 	strcpy(sd->sys_name, "dev-");
 	strcpy(sd->sys_name+4, dname);