svn lock ends with an error E000001: Can't set permissions on '..../test.svn/db': Operation not permitted

Hi,

after upgrading to 1.7.x i've noticed some bug in svn lock machinery.
here's a reduced testcase with local repo.

1). create from root a repo and change owner/mod to svnadmin.svnusers.

# svnadmin create test.svn
# chown -R svnadmin.svnusers test.svn
# chmod g+ws test.svn/db -R

2). from user that belongs to svnusers group try to do this:

$ svn co file://<$fullpath>/test.svn test.wc
Checked out revision 0.
$ cd test.wc
$ touch file
$ svn add file
A file
$ svn ci file -m 'dropin'
Adding file
Transmitting file data .
Committed revision 1.
$ svn lock file
svn: E000001: Can't set permissions on '/home/users/pawels/bugs/test.svn/db'
svn: E000001: Can't set permissions on '/home/users/pawels/bugs/test.svn/db': Operation not permitted

the strace shows that svn tries to chmod() on db directory.

(...)
chmod("/home/users/pawels/bugs/test.svn/db", 02755) = -1 EPERM (Operation not permitted)
(...)
Received on 2011-12-15 15:47:27 CET