rsync - Mar 2005 - Why does "rsync -av" always claim (incorrectly?) that it is updating write protected directories?

Hi,

	I usually run "rsync -av" so I can see all the files that have
been modified.

	However, "rsync -av" always claims to be updating write
protected directories, even when they have not been changed.  I do not
understand why.

	Here is an example using rsync version 2.6.3 on FreeBSD 5.3.
I get similar results with rsync 2.6.0 on Gentoo Linux.

--------
$ mkdir dir0
$ touch dir0/file
$ rsync -av dir0 dir1
building file list ... done
created directory dir1
dir0/
dir0/file

sent 127 bytes  received 40 bytes  334.00 bytes/sec
total size is 0  speedup is 0.00
--------

	So I have created dir0 and rsynced it to inside of dir1.  This
is all okay.

--------
$ rsync -av dir0 dir1
building file list ... done

sent 87 bytes  received 20 bytes  214.00 bytes/sec
total size is 0  speedup is 0.00
--------

	I have rsynced it again.  rsync shows that no files have
changed.  This is all okay.

--------
$ ls -l dir1
total 2
drwxr-xr-x  2 parke  parke  512 Mar  3 12:06 dir0
$ chmod -w dir0
$ rsync -av dir0 dir1
building file list ... done

sent 87 bytes  received 20 bytes  214.00 bytes/sec
total size is 0  speedup is 0.00
$ ls -l dir1
total 2
dr-xr-xr-x  2 parke  parke  512 Mar  3 12:06 dir0
--------

	We see that dir1/dir0 is writable.  I "chmod -w dir0".  Then I
"rsync -av" and rsync does not report that it has changed any files.
However, we can see that dir1/dir0 is no longer writable.  So rsync
did change the permissions on dir1/dir0 (as it should have), it just
did not report that it changed the permissions.  Why not?

--------
$ rsync -av dir0 dir1
building file list ... done
dir0/

sent 87 bytes  received 20 bytes  214.00 bytes/sec
total size is 0  speedup is 0.00
--------

	I rsync again.  This time rsync claims that it is changing
"dir0/".  However, as far as I can tell, rsync is NOT changing
anything.  What am I missing here?

--------
$ rsync -av dir0 dir1
building file list ... done
dir0/

sent 87 bytes  received 20 bytes  214.00 bytes/sec
total size is 0  speedup is 0.00
--------

	We can repeat the "rsync -av" as many times as we want.  rsync
will now always claim (incorrectly?) that it is modifying "dir0/".
Why?

--------
$ chmod u+w dir0
$ rsync -av dir0 dir1
building file list ... done
dir0/

sent 87 bytes  received 20 bytes  214.00 bytes/sec
total size is 0  speedup is 0.00
--------

	I make dir0 writable again.  I rsync.  rsync makes dir1/dir0
writable, as it should.  rsync reports that it has changed "dir0/", as
it should.  Everything is okay here.

--------
$ rsync -av dir0 dir1
building file list ... done

sent 87 bytes  received 20 bytes  214.00 bytes/sec
total size is 0  speedup is 0.00
$ rsync -av dir0 dir1
building file list ... done

sent 87 bytes  received 20 bytes  214.00 bytes/sec
total size is 0  speedup is 0.00
--------

	Two more rsyncs with nothing to change and no changes
reported.  This is okay.


	So... to summarize: When I "rsync -av" write protected
directories, rsync always (and incorrectly?) claims that it is
changing those directories, even thought, as far as I can tell, rsync
is not changing the directories.
	Is this a bug?  Is there something I do not understand?

	Thanks!

	Matthew.
______________________________________________________________________
                                                     mb@mb.mbostrom.us

On Thu, Mar 03, 2005 at 12:32:39PM -0800, Matthew Bostrom
wrote:
> 	However, "rsync -av" always claims to be updating write
> protected directories, even when they have not been changed.  I do not
> understand why.
The reason is that rsync always tries to update the time on the
directories in the transfer to match the sender, but it ignores
any error generated from that operation because some OSes don't
allow the time of a directory to be set to anything other than
"now" by a normal user.  Thus, rsync attempts to set the time on
these dirs on every run.

In 2.6.4 (not yet released) there is an option, --omit-dir-times (-O),
that turns off the preservation of directory times.  Because it is now
possible to disable this, rsync no longer hides the error from a failed
directory time-set -- it lets you know that it is failing, and you can
then choose to use -O to tell rsync that it is OK to not set the times
on the dirs (or you might notice the problem and fix it, etc.).

..wayne..