collectd-mod-disk: does not see some partitions

19.07-SNAPSHOT
GL-B1300

I want to monitor /dev/mtdblock11, but the plugin only sees disk-mtdblock10 and none of the other partitions. Is it because mtdblock11 is jffs2?

config statistics 'collectd_disk'
        option enable '1'
        option IgnoreSelected '0'
        option Disks 'mtdblock0 mtdblock1 mtdblock2 mtdblock3 mtdblock4 mtdblock5 mtdblock6 mtdblock7 mtdblock8 mtdblock9 mtdblock10 mtdblock11'

df -h
Filesystem                Size      Used Available Use% Mounted on
/dev/root                10.8M     10.8M         0 100% /rom
tmpfs                   122.5M    296.0K    122.3M   0% /tmp
tmpfs                   122.5M    524.0K    122.0M   0% /tmp/root
tmpfs                   512.0K         0    512.0K   0% /dev
/dev/mtdblock11          17.1M      1.6M     15.5M  10% /overlay
overlayfs:/overlay       17.1M      1.6M     15.5M  10% /

mount
/dev/root on /rom type squashfs (ro,relatime)
proc on /proc type proc (rw,nosuid,nodev,noexec,noatime)
sysfs on /sys type sysfs (rw,nosuid,nodev,noexec,noatime)
tmpfs on /tmp type tmpfs (rw,nosuid,nodev,noatime)
tmpfs on /tmp/root type tmpfs (rw,noatime,mode=755)
tmpfs on /dev type tmpfs (rw,nosuid,relatime,size=512k,mode=755)
devpts on /dev/pts type devpts (rw,nosuid,noexec,relatime,mode=600,ptmxmode=000)
debugfs on /sys/kernel/debug type debugfs (rw,noatime)
/dev/mtdblock11 on /overlay type jffs2 (rw,noatime)
overlayfs:/overlay on / type overlay (rw,noatime,lowerdir=/,upperdir=/overlay/upper,workdir=/overlay/work)

cat /proc/partitions 
major minor  #blocks  name

  31        0        256 mtdblock0
  31        1        128 mtdblock1
  31        2        384 mtdblock2
  31        3         64 mtdblock3
  31        4         64 mtdblock4
  31        5         64 mtdblock5
  31        6        512 mtdblock6
  31        7         64 mtdblock7
  31        8      31232 mtdblock8
  31        9       2880 mtdblock9
  31       10      28397 mtdblock10
  31       11      17536 mtdblock11

Start at the collectd-mod-disk plugin entry point and reproduce the reported configuration with the /dev/mtdblock11 and /proc/partitions data shown here. Compare how the plugin handles mtdblock10, mtdblock11, and the jffs2-mounted overlay; the issue is done when the omission is explained and the configured partition is handled consistently with the others.