A few more pieces of information that might be useful:
By placing trace data in upstart scripts, it seems that the mountall job is correctly executed, but the rc-sysinit job isn't, even with the actual mounting command commented out (so it's not hanging inside the mounting process). Note that the mountall job emits the filesystem event and rc-sysinit is supposed to start on filesystem.
A few more pieces of information that might be useful:
By placing trace data in upstart scripts, it seems that the mountall job is correctly executed, but the rc-sysinit job isn't, even with the actual mounting command commented out (so it's not hanging inside the mounting process). Note that the mountall job emits the filesystem event and rc-sysinit is supposed to start on filesystem.