Cannot mount hfs partition on read/write

Question

In ubuntu 15.10 I am trying to mount a hfs (max osx) partition on start up. In /etc/fstab I have added this line (notice the rw option):

/dev/sda2 /home/mac/mac-mount hfsplus rw,defaults 0 0

After a reboot the drive is mounted but I cannot create new content on the drive:

:~/mac-mount/Users/mac-mini/Documents$ touch test.txt
touch: cannot touch ‘test.txt’: Read-only file system

Running mount gives me the below for that particular partition:

/dev/sda2 on /home/mac/mac-mount type hfsplus (ro,relatime,umask=22,uid=0,gid=0,nls=utf8)

notice it says ro. Why is the hfs partition not mounted in rw given the /etc/fstab file above?

I have also tried to change the permissions for the mount point with:

~$ sudo chmod o+w mac-mount/
[sudo] password for mac:
chmod: changing permissions of ‘mac-mount/’: Read-only file system

But it gives the above error.

UPDATE: Based on the below answer I now have it working with write permissions after disabling Journaling. But for some reason it only works on some folders (I managed to create a test file in the Documents folder). As and example I cannot even cd to the Downloads folder on the hfs partition:

drwxr-xr-x 1  501 dialout    17 Dec 29 14:12 .
drwxr-xr-x 1 root      80     6 Oct  6 16:54 ..
drwx------ 1  501 dialout     3 Aug 10  2014 Applications
-rw-r--r-- 1  501 dialout    56 Dec 29 14:12 .bash_history
drwxr-xr-x 1  501 dialout     5 Dec 29 14:12 .bash_sessions
-r-------- 1  501 dialout     7 Feb 14  2015 .CFUserTextEncoding
drwx------ 1  501 dialout     4 Oct 13 18:30 Desktop
drwx---rwx 1  501 dialout    12 Dec 29 14:15 Documents
drwx------ 1  501 dialout     6 Dec 29 14:11 Downloads
-rw-r--r-- 1  501 dialout 14340 Dec 29 14:10 .DS_Store
drwx------ 1  501 dialout    52 Oct  6 17:13 Library
drwx------ 1  501 dialout     3 Aug 10  2014 Movies
drwx------ 1  501 dialout     5 Sep 13  2014 Music
drwxr-xr-x 1  501 dialout     3 Oct 28 11:34 .oracle_jre_usage
drwx------ 1  501 dialout     8 Apr 17  2015 Pictures
drwxr-xr-x 1  501 dialout     5 Aug 10  2014 Public
drwx------ 1  501 dialout     6 Dec 27 01:49 .Trash
:~/mac-mount/Users/mac-mini$ cd Downloads/
-bash: cd: Downloads/: Permission denied
:~/mac-mount/Users/mac-mini$ cd Documents/
:~/mac-mount/Users/mac-mini/Documents$

So why can I cd to Documents but not Downloads folder? I have not modified any permissions while using my mac-mini directly.

Answer 1

You can mount this filesystem in Ubuntu with read only access by default. If you need read/write access then you have to disable journaling with OS X before you can continue.

You can identify the volume with:

sudo diskutil list

and take note of the volume with type "Apple_HFS", usually named "Macintosh HD"

To disabile journaling in OSX type in a terminal:

sudo diskutil disableJournal volumeName

If you want access in rw mode for a non root user you need to change your Ubuntu User ID (UID) to match your UID under OSX.

Assuming you are logged in as a regular user who has sudo rights. Substitute the username for the Linux user you wish to enable HFS+ write access for and 501 for the relevant OSX UID. You have to modify also the linux UID for the user's home:

sudo usermod -u 501 <username>
sudo chown -R 501:<username> /home/<username> 

If there are in your system others files that belongs to the user you can change alla UIDs in one command. Take note of your UID (with id command), then:

find / -uid <useractualUID> -exec chown 501:<username> {} +

You may also want to fix your login screen, by default Ubuntu doesn't list users with a UID < 1000. Open a Terminal and run

sudo nano /etc/login.defs

Then search for UID_MIN. Change that value from 1000 to 501, when you reboot your user will be listed on the login screen.