Operating System is RHEL 8.6:

I have created a udev rule that restricts USB devices to read-only and it appears to work as expected for USB 2.x and USB 3.x devices, but for large USB 3.x devices - it does not appear to work correctly.

The contents of the rule seem pretty simple:

cat /etc/udev/rules.d/80-readonly-removables.rules

ACTION=="add", SUBSYSTEM=="block", ATTRS{removable}=="1", ENV{ID_USB_DRIVER}=="usb-storage", RUN{program}="/sbin/blockdev --setro %N"

After mounting 2 USB 3.x devices the 16gb device is mount in read-only mode, while the 512gb device is in rw mode.

(cmd)root:~# mount | grep -E 'sd[a,b]'
/dev/sdb on /mnt/usb_16gb type ext4 (ro,relatime,seclabel)
/dev/sda on /mnt/usb_512gb type ext4 (rw,relatime,seclabel,stripe=8191)

Running the "udevadm test" against the 2 devices shows the devices are loading identical rules.

My goal is to have any USB device mounted to the machine be read-only.

Any ideas on how to troubleshoot this issue and isolate why large USB 3.x devices are being mounted in read-write rather than read-only as defined in the rule?