Bug 165245

Version:           1.0.2 (using KDE 4.0.5)
Installed from:    SuSE RPMs
Compiler:          gcc 4.2.1 
OS:                Linux

KDE does not start, if the home directory is a CIFS mount. I use samba-3.0.26a-3.7 (Server) and cifs-mount-3.0.26a-3.7 (Client) on Linux (openSUSE 10.3). cifs-mount should provide enough UNIX compatibility to run any Unix application (including symlinks, hard links etc.).

There are problems with lockfiles for kconf_update in the X session logs:

WARNING: Problem deleting stale lockfile /home/bv/.kde4/share/config/kconf_updaterc.lock
WARNING: Problem deleting stale lockfile /home/bv/.kde4/share/config/kconf_updaterc.lock
WARNING: Problem deleting stale lockfile /home/bv/.kde4/share/config/kconf_updaterc.lock
[...]
(endless loop)

The problem already exists on KDE 3.x. But I also find the problem on KDE 4.0.5. The source code already contains some work arounds for the file locking problem for SMBFS (a predecessor of CIFS) shares:

http://lxr.kde.org/source/KDE/kdelibs/kdecore/io/klockfile_unix.cpp:
225    // SMBFS supports hardlinks by copying the file, as a result the above test will always fail
226    if (linkCountSupport)
227    {
228       linkCountSupport = testLinkCountSupport(tmpFile);
229    }
230 
231    if (!linkCountSupport &&
232        (KDE_lstat(lckFile, &st_buf2) == 0) && st_buf == st_buf2)
233    {
234       // Without support for link counts we will have a little race condition
235       qWarning("WARNING: deleting stale lockfile %s", lckFile.data());
236       ::unlink(lckFile);
237       ::unlink(tmpFile);
238       return KLockFile::LockOK;
239    }
240 
241    // Failed to delete stale lock file
242    qWarning("WARNING: Problem deleting stale lockfile %s", lckFile.data());
243    ::unlink(tmpFile);
244    return KLockFile::LockFail;

linkCountSupport is false on in my setup. But the second check (KDE_lstat(lckFile, &st_buf2) == 0) && st_buf == st_buf2 is also false because the st_link fields are not equal. As the result, the error message "WARNING: Problem deleting stale lockfile %s" is displayed.

Without a fix for this problem the KDE start script runs in an infinite loop, because kconf_update does not terminate. Probably also single KDE applications may fail on CIFS, because some of them use the KLockFile class, which is broken for CIFS.