Re: [Bug-tar] Unchanged directories in listed-incremental level 1

[Joerg Schilling]

David <address@hidden> wrote:

> On 13 July 2010 04:47, Joerg Schilling
> <address@hidden> wrote:
> > David <address@hidden> wrote:
> >
> >> Using gnu tar 1.22 on ext3 here, every level 1 incremental archive
> >> created contains an entry for every unchanged subdirectory. This
> >> disagrees with the expected behaviour described in the manual.
> >
> > From my view, it it not really important whether the documentation matches
> > actual behavior. It is of course desirable that the documentation is right,
> > but does GNU tar _do_ what you expect?
>
> Thank you for your interest. However your assumed use case differs from mine,
> so please do not dismiss my query on that basis.
>
> I am using incremental tar to create an easily browseable history organised by
> differential changes, that can easily be selectively purged. I will never need
> to do the full restore that you describe.

Then it may be that it is better to just call find(1). I recommend to call:

        find . -ctime #

Some find implementations support "-newerXY file", in this case, you could use:

        find . -newercm stamp-file

As this forces a find implementation to call stat(2) for each file, it will not
triger the GNU find bug that is based on making illegal assumptions on the 
link count of directories.

> You did not quote what is to me the most important sentence of my original 
> post:
>
> >> This issue makes it difficult to work with my level 1 archives that
> >> contain thousands of these useless empty unchanged directory entries.
>
> Thank you for helping to clarify my issue.

As mentioned before, the algorithm used by GNU find may be different, but star
is based on the proven algorithm used by ufsdump:

Archive any file which's ctime in the timestamps is newer than the last related
dump.

This will include the directories where files have been renamed but not 
directories where files only have been modified.

Jörg

-- 
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