The OS X filesystem, HFS+, by default is in read-only mode in my ubuntu.

sudo apt-get install hfsprogs

 (you have to enable universe package-source)

 to mount the "Macintosh HD", use this

$cd 
$mkdir osx
$sudo mount -t hfsplus -o force,rw /dev/sda2 osx 

 Nevertheless, it still mounted as read-only, and some folders refused to open at all.

 Here the trick. We have to have same uid as the os x.

 so, create new user

sudo useradd -d /home/newuser -m -s /bin/bash -G root newuser

sudo passwd newuser

sudo usermod --uid 501 newuser

sudo chown -R 501:newuser /home/newuser

.

 by default the first user on OSX has an uid 501.

 Now, as we have the same uid on linux and OS X. We could freely read the filesystem.