What does 'rw' mean when bind mounting a directory

will be helpful for those in need I'm not familiar with Android, but if you want to mount a directory instead of a device you have to use mount with the --bind option.
If it's really a file then maybe your Android has no loop device support. Do you have any /dev/loop* devices?

this will help The VOLUME statement in a Dockerfile just marks the directory as to be mounted from somewhere else to help users of the image. For example when you create a Database-Image, the user of that image usually wants to persist the date outside of the container.
If you (as the creator of the Image/writer of the Dockerfile) marked a directory as a VOLUME, the user of the image (the one who executes docker run or similar) has an idea, where in the container he should mount a directory from outside.

To fix this issue Host volumes: For a host volume, defined with a path in your docker compose file like:

volumes:
  - "./wordpress/uploads:/var/www/html/wp-content/uploads"

version: "2"

services:
  your-service:
    volumes:
      - uploads:/var/www/html/wp-content/uploads

volumes:
  uploads:
    driver: local
    driver_opts:
      type: none
      o: bind
      device: /path/on/host/to/wordpress/uploads

testvol/
  data-image/
    sub-dir/
      from-image
  data-submount/
  Dockerfile
  docker-compose.yml

FROM busybox
COPY data-image/ /data

version: "2"

services:
  test:
    build: .
    image: test-vol
    command: find /data
    volumes:
      - data:/data
      - subdir:/data/sub-dir

volumes:
  data:
  subdir:
    driver: local
    driver_opts:
      type: none
      o: bind
      device: /path/on/host/test-vol/data-submount

$ docker run -it --rm -v testvol_data:/data busybox find /data
/data
/data/sub-dir
/data/sub-dir/from-named-vol

$ docker-compose -f docker-compose.bind.yml up
...
Attaching to testvol_test_1
test_1  | /data
test_1  | /data/sub-dir
test_1  | /data/sub-dir/from-image
testvol_test_1 exited with code 0

$ ls -l data-submount/
total 0
-rw-r--r-- 1 root root 0 Jan 15 08:08 from-image

This might help you After installing cifs package the mounting command worked!
It was because the base image I used was an Alpine image. Unlike Linux Alpine doesn't give proper error that the package is missing rather gives a common error