file copy problem: filename too long

[Aere Greenway]

On 09/26/2015 01:33 AM, Tom Cloyd wrote:
> Something I might mention which could have bearing. For professional 
> reasons, I need to have at least my main personal account directory 
> encrypted.  So, I took the encryption option offered when installing 
> Lubuntu (I had been running Kubuntu). But I didn't get the same 
> response for both desktop and netbook. (Recall that with the netbook I 
> am NOT having this filelength copy issue).
>
> I neglected to take notes, and cannot reliably recall, but on one of 
> the installs I WAS able to encrypt the whole disk. On the other 
> install, the installer refused to do that and would only let me 
> encrypt /home. Can you tell, looking at the above, which machine has 
> only /home encrypted?
>
> I hope this is the information you need. Thanks for your help. Much 
> appreciated.
Tom:

An idea I had of the cause was that in copying from EXT4 file-systems 
(such as Linux uses) to FAT32 (an older Windows file-system that is 
commonly used on USB flash drives), you can end up with filenames that 
are too long (or have illegal characters in them) for the FAT32 
file-system.

There is a similar problem in copying files to a CD or DVD, which uses a 
Joliet file-system, and the software for doing such copies has an 
algorithm for shortening filenames that are too long.

Where you mentioned that you use encryption, that means the file-names 
are also encrypted, and therefore use very long filenames, which 
probably contain special characters as well.

The information you supplied (which was sufficient for me), indicates 
your USB drive uses an EXT4 file-system, which has no problems with long 
filenames (and allows a lot of special characters in filenames).  Also, 
the file-system you are trying to copy to is also EXT4, so there should 
be no problem.

Unfortunately, you use encryption (which I have only limited experience 
with), as well as LVM drives (which I currently have no experience 
with).  Given my lack of experience in those areas, my conclusions are 
just guesses.

Usually, when you copy an encrypted directory to somewhere else, you 
must first be able to access it in un-encrypted form (you enter your 
password, and then the filenames are readable, not having special 
characters in them, and are of reasonable length).  If you want it 
encrypted where you copied it to, you encrypt it there, as a separate step.

My guess (and it is a guess) is that you are copying the files while 
still in encrypted form, having long filenames with special characters, 
which results in your errors.

It looks like your system you call "desk top" has its /home/tomc folder 
encrpyted (a question you asked).

I hope this information (and my guesses) help you figure out what is wrong.

-- 
Sincerely,
Aere