mdev: fix non-working device deletion, add a test for that

Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>

testsuite/mdev.tests

@@ -37,6 +37,16 @@ brw-rw---- 1 0 0 8,0 sda
 	"" ""
 SKIP=
 
+# continuing to use directory structure from prev test
+optional STATIC FEATURE_MDEV_CONF FEATURE_LS_TIMESTAMPS FEATURE_LS_USERNAME
+testing "mdev deletes /block/sda" \
+	"env - PATH=$PATH ACTION=remove DEVPATH=/block/sda chroot mdev.testdir /mdev 2>&1;
+	ls -ln mdev.testdir/dev | $FILTER_LS" \
+"\
+" \
+	"" ""
+SKIP=
+
 # continuing to use directory structure from prev test
 rm -rf mdev.testdir/dev/*
 echo ".* 1:1 666" >mdev.testdir/etc/mdev.conf

util-linux/mdev.c

@@ -132,6 +132,7 @@ static void make_device(char *path, int delete)
 			major = -1;
 		}
 	}
+	/* else: for delete, -1 still deletes the node, but < -1 suppresses that */
 
 	/* Determine device name, type, major and minor */
 	device_name = (char*) bb_basename(path);
@@ -279,7 +280,7 @@ static void make_device(char *path, int delete)
 				if (aliaslink == '!' && s == a+1) {
 					val = st;
 					/* "!": suppress node creation/deletion */
-					major = -1;
+					major = -2;
 				}
 				else if (aliaslink == '>' || aliaslink == '=') {
 					val = st;
@@ -379,7 +380,7 @@ static void make_device(char *path, int delete)
 				free(command);
 			}
 
-			if (delete && major >= 0) {
+			if (delete && major >= -1) {
 				if (ENABLE_FEATURE_MDEV_RENAME && alias) {
 					if (aliaslink == '>')
 						unlink(device_name);