test: change partition label to test if the outdated devlinks are removed

The change is intended to reproduce the issue #27983, though the
original issue is highly racy, and the test does not reproduce it
reliably. But, anyway, it is better to change the partition label to
test the devlink removal.

test/units/testsuite-64.sh

@@ -444,10 +444,14 @@ EOF
 }
 
 testcase_simultaneous_events_2() {
-    local disk expected i iterations key link num_part part partscript target timeout
+    local disk expected i iterations key link num_part part script_dir target timeout
     local -a devices symlinks
     local -A running
 
+    script_dir="$(mktemp --directory "/tmp/test-udev-storage.script.XXXXXXXXXX")"
+    # shellcheck disable=SC2064
+    trap "rm -rf '$script_dir'" RETURN
+
     if [[ -v ASAN_OPTIONS || "$(systemd-detect-virt -v)" == "qemu" ]]; then
         num_part=20
         iterations=1
@@ -469,13 +473,11 @@ testcase_simultaneous_events_2() {
         devices+=("$target")
     done
 
-    symlinks=("/dev/disk/by-partlabel/testlabel")
-
-    partscript="$(mktemp)"
-
-    cat >"$partscript" <<EOF
-$(for ((part = 1; part <= num_part; part++)); do printf 'name="testlabel", size=1M\n'; done)
+    for ((i = 1; i <= iterations; i++)); do
+        cat >"$script_dir/partscript-$i" <<EOF
+$(for ((part = 1; part <= num_part; part++)); do printf 'name="testlabel-%d", size=1M\n' "$i"; done)
 EOF
+    done
 
     echo "## $iterations iterations start: $(date '+%H:%M:%S.%N')"
     for ((i = 1; i <= iterations; i++)); do
@@ -491,7 +493,7 @@ EOF
         done
 
         for disk in {0..9}; do
-            udevadm lock --device="${devices[$disk]}" sfdisk -q -X gpt "${devices[$disk]}" <"$partscript" &
+            udevadm lock --device="${devices[$disk]}" sfdisk -q -X gpt "${devices[$disk]}" <"$script_dir/partscript-$i" &
             running[$disk]=$!
         done
 
@@ -500,7 +502,7 @@ EOF
             unset "running[$key]"
         done
 
-        udevadm wait --settle --timeout="$timeout" "${devices[@]}" "${symlinks[@]}"
+        udevadm wait --settle --timeout="$timeout" "${devices[@]}" "/dev/disk/by-partlabel/testlabel-$i"
     done
     echo "## $iterations iterations end: $(date '+%H:%M:%S.%N')"
 }