Re: [Bug-tar] Problem with gnu tar and ZFS on Linux

[Pieter Bowman]

>> ...
>> On 06/21/2018 09:53 AM, Andreas Dilger wrote:
>> > Keep your old snapshot around after you create the new one, and run 
>> > "stat(1)"  > on the same file in both snapshots to see if there are any 
>> > other 
>> differences > besides the device number that may be causing tar to think 
>> the file changed.
>> Yes, this is the key. You need to find out why 'tar' thinks the 
>> directory has changed, and 'stat' should tell you why.
>> 
>> ...

The problem seems to be caused by the changing of the inode of the
root of that filesystem.  The inode for the test filesystem's root
directory is 3, the inode for various snapshots are numbers like:

281474976666177
281474976671479
281474976673971

So I applied the patch at the following URL to tar 1.30 (applied
partially by hand because it had one hunk that was rejected):

https://pastebin.com/ZjpqYJk3

Now if I run this test version of tar, I get a reasonable incremental
size.

Unfortunately, the patch only implements the feature, but no
documentation or tests.

Pieter