diff --git a/Assemble.c b/Assemble.c
index 4e4e123..ace5717 100644
--- a/Assemble.c
+++ b/Assemble.c
@@ -193,7 +193,7 @@ int Assemble(char *mddev, int mdfd,
 			continue;
 		}
 		
-		dfd = open(devname, O_RDONLY, 0);
+		dfd = open(devname, O_RDONLY|O_EXCL, 0);
 		if (dfd < 0) {
 			if (inargv || verbose)
 				fprintf(stderr, Name ": cannot open device %s: %s\n",
@@ -326,7 +326,7 @@ int Assemble(char *mddev, int mdfd,
 				super.recovery_cp = 0;
 			}
 			super.sb_csum = calc_sb_csum(&super);
-			dfd = open(devname, O_RDWR, 0);
+			dfd = open(devname, O_RDWR|O_EXCL, 0);
 			if (dfd < 0) 
 				fprintf(stderr, Name ": Cannot open %s for superblock update\n",
 					devname);
@@ -435,7 +435,7 @@ int Assemble(char *mddev, int mdfd,
 			devices[chosen_drive].devname, devices[chosen_drive].raid_disk,
 			(int)(devices[chosen_drive].events),
 			(int)(devices[most_recent].events));
-		fd = open(devices[chosen_drive].devname, O_RDWR);
+		fd = open(devices[chosen_drive].devname, O_RDWR|O_EXCL);
 		if (fd < 0) {
 			fprintf(stderr, Name ": Couldn't open %s for write - not updating\n",
 				devices[chosen_drive].devname);
@@ -484,7 +484,7 @@ int Assemble(char *mddev, int mdfd,
 		if (!devices[j].uptodate)
 			continue;
 		chosen_drive = j;
-		if ((fd=open(devices[j].devname, O_RDONLY))< 0) {
+		if ((fd=open(devices[j].devname, O_RDONLY|O_EXCL))< 0) {
 			fprintf(stderr, Name ": Cannot open %s: %s\n",
 				devices[j].devname, strerror(errno));
 			return 1;
@@ -556,7 +556,7 @@ This doesnt work yet
 	    || (old_linux && (change & 1))) {
 		int fd;
 		super.sb_csum = calc_sb_csum(&super);
-		fd = open(devices[chosen_drive].devname, O_RDWR);
+		fd = open(devices[chosen_drive].devname, O_RDWR|O_EXCL);
 		if (fd < 0) {
 			fprintf(stderr, Name ": Could open %s for write - cannot Assemble array.\n",
 				devices[chosen_drive].devname);
diff --git a/ChangeLog b/ChangeLog
index 7e03a5c..6854858 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,7 @@
+Changes Prior to 1.10.0 release
+    -   Fix bug with --config=partitions
+    -   Open sub-devices with O_EXCL to detect if already in use
+
 Changes Prior to 1.9.0 release
     -   Fix rpm build problem (stray %)
     -   Minor manpage updates
diff --git a/Create.c b/Create.c
index 1c814f7..66a88d2 100644
--- a/Create.c
+++ b/Create.c
@@ -187,7 +187,7 @@ int Create(char *mddev, int mdfd,
 		array.working_disks++;
 		if (dnum < raiddisks)
 			array.active_disks++;
-		fd = open(dname, O_RDONLY, 0);
+		fd = open(dname, O_RDONLY|O_EXCL, 0);
 		if (fd <0 ) {
 			fprintf(stderr, Name ": Cannot open %s: %s\n",
 				dname, strerror(errno));
@@ -368,7 +368,7 @@ int Create(char *mddev, int mdfd,
 			disk.minor = 0;
 			disk.state = 1; /* faulty */
 		} else {
-			fd = open(dv->devname, O_RDONLY, 0);
+			fd = open(dv->devname, O_RDONLY|O_EXCL, 0);
 			if (fd < 0) {
 				fprintf(stderr, Name ": failed to open %s after earlier success - aborting\n",
 					dv->devname);
diff --git a/Kill.c b/Kill.c
index a57bdf8..9441f73 100644
--- a/Kill.c
+++ b/Kill.c
@@ -44,7 +44,7 @@ int Kill(char *dev, int force)
 	mdp_super_t super;
 	int fd, rv = 0;
 		
-	fd = open(dev, O_RDWR);
+	fd = open(dev, O_RDWR|O_EXCL);
 	if (fd < 0) {
 		fprintf(stderr, Name ": Couldn't open %s for write - not zeroing\n",
 			dev);
diff --git a/Manage.c b/Manage.c
index 8835095..b323fd3 100644
--- a/Manage.c
+++ b/Manage.c
@@ -194,6 +194,14 @@ int Manage_subdevs(char *devname, int fd,
 			return 1;
 		case 'a':
 			/* add the device - hot or cold */
+			/* Make sure it isn' in use (in 2.6 or later) */
+			fd = open(dv->devname, O_RDONLY|O_EXCL);
+			if (fd < 0) {
+				fprintf(stderr, Name ": Cannot open %s: %s\n",
+					dv->devname, strerror(errno));
+				return 1;
+			}
+			close(fd);
 			if (ioctl(fd, HOT_ADD_DISK, (unsigned long)stb.st_rdev)==0) {
 				fprintf(stderr, Name ": hot added %s\n",
 					dv->devname);