test-repart: use cryptsetup and losetup autoclose

The test occasionally fails as the umount is not yet completed when
cryptsetup close is invoked.
Both cryptsetup and losetup have supported deferred cleanup for some
time now, so use it instead to avoid races.

++ losetup -P --show --find /tmp/test-repart.dMOfYQ8UUF/zzz
+ LOOP=/dev/loop6
+ VOLUME=test-repart-11882
+ touch /tmp/test-repart.dMOfYQ8UUF/empty-password
+ cryptsetup open --type=luks2 --key-file=/tmp/test-repart.dMOfYQ8UUF/empty*** test-repart-11882
+ mkdir /tmp/test-repart.dMOfYQ8UUF/mount
+ mount -t ext4 /dev/mapper/test-repart-11882 /tmp/test-repart.dMOfYQ8UUF/mount
+ diff -r /tmp/test-repart.dMOfYQ8UUF/mount/def /tmp/test-repart.dMOfYQ8UUF/definitions
+ umount /tmp/test-repart.dMOfYQ8UUF/mount
+ cryptsetup close test-repart-11882
Device test-repart-11882 is still in use.
+ rm -rf /tmp/test-repart.dMOfYQ8UUF

src/partition/test-repart.sh

@@ -200,10 +200,11 @@ EOF
     cryptsetup open --type=luks2 --key-file=$D/empty-password ${LOOP}p7 $VOLUME
     mkdir $D/mount
     mount -t ext4 /dev/mapper/$VOLUME $D/mount
+    # Use deferred closing on the mapper and autoclear on the loop, so they are cleaned up on umount
+    cryptsetup close --deferred $VOLUME
+    losetup -d $LOOP
     diff -r $D/mount/def $D/definitions > /dev/null
     umount $D/mount
-    cryptsetup close $VOLUME
-    losetup -d $LOOP
 else
     echo "### Skipping Format=/Encrypt=/CopyFiles= test, lacking privileges or missing cryptsetup/diff/losetup"
 fi