Unable to preserve hard links. Why?


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Top Forums Shell Programming and Scripting Unable to preserve hard links. Why?
# 8  
Oh /dev/full. This thread is not any help because everybody thinks that I've did something plainly stupid. I'm feeling like I've just called an IT support. Smilie

Please, before posting anything stop for a moment and think what I'm doing or just fire the script, give it 30 minutes and see the results.

I'm trying to copy filesystem from the read-only compressed loop device to normal filesystem to be able to modify it and then compress it to replace the old one. That's what Knoppix remastering is all about. I have to preserve all the details about the filesystem i.e. recreate hard link structure from one filesystem on the other filesystem. The ls -li that I've pasted is the same file in two different filesystem to show that source had hardlinks and the destination have lost them.

This is obviously possible -- if the rsync is able to preserve hardlinks between different hosts it should be able to do it on between filestems on the same host.

For some strange reason this is not working using neither of three methods that I'm aware that should do the job and I'm puzzled what is wrong. I've spent almost a workday to create the script, test it and this seems to be a last piece that stops it from fully working.

I have a test suite and a part of it is counting md5sums from both filesystems and the diff is empty - meaning that content of every file between filesystem is exactly the same. However, the diff between permissions and hard link numbers shows that every file that was refering to shared (hard-linked) inode is now a separate inode which is not what I wanted. So I'm quite sure that the tar syntax is somehow working but is not really important because all the three methods are doing the same thing wrong which is really suspicious and I'm running out of ideas.

So, please stop trying to find typos and stupid bugs and start be creative. Smilie

---------- Post updated at 10:03 AM ---------- Previous update was at 09:02 AM ----------

It seems I've found it!

CD-record mailing list

But what can I do about it?
# 9  
We only know as much as you tell us, and a makefile without the files it works on is not a lot. A silly makefile doesn't tell me a thing about your file layout, I still don't know after asking three times if you ever fixed your use of tar, in fact the most I've gotten from you -- beyond abuse -- is one ls readout of only a quarter of the files I asked for. A real listing of all the hardlinked input (and output) files could have been helpful(and would still be), but you treat it like an RTFM.
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It seems I've found it!

CD-record mailing list
If you're trying to create an ISO with rock-ridge hard links, yes, that is a problem. Is the input truly Rock Ridge? Usually on livecd's I see compressed filesystems done as cramfs and the like.

Preserving hard links doesn't seem to matter to me when creating a read-only filesystem. The permissions, contents, and owners are still all as they should be, and nothing will ever be able to change it.

Last edited by Corona688; 08-27-2010 at 12:50 PM..
# 10  
There is no filesystem layout beside that Makefile. It downloads everything.

I've found the root of the problem with little help from here Unable to preserve hard links. Why? - Super User .

Thanks anyway.
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