Re: 1.7.7: rm -rf sometimes fails - race condition?

[Corinna Vinschen <corinna-cygwin at cygwin dot com>]

On Dec 12 16:19, Corinna Vinschen wrote:
> On Dec 12 16:14, Matthias Andree wrote:
> > Am 12.12.2010 16:12, schrieb Corinna Vinschen:
> > > On Dec 12 15:16, Matthias Andree wrote:
> > >> Am 12.12.2010 13:42, schrieb Corinna Vinschen:
> > >> 
> > >> > So, what cygwin tries to do in the first place is to move files in use
> > >> > into the recycle bin.  However, on Windows you need DELETE access rights
> > >> > to be able to do so.  And, this doesn't work for remote drives.  On
> > >> > remote drives we can only try to rename the file to some temporary
> > >> > filename and hope for the best.  Afterwards Cygwin sets the delete
> > >> > dispostion flag and returns success if setting the dispostion flag
> > >> > succeeded.  After all, that's the maximum possible on Windows, and for
> > >> > all we can tell the file has been deleted.  The fact that the directory
> > >> > entry lingers until the last handle to the file has been closed is
> > >> > something Cygwin has no control over.
> > >> 
> > >> Well, there's the problem.
> > > 
> > > No, it's not, at least not on local drives.  Read again.  Files and
> > > directories in use are moved into the bin.  If that fails, unlink/rmdir
> > > fails.
> > 
> > Then I wonder what makes my cygport (or the rm command it uses) fail as it
> > removes the workdir...
> 
> I guess debugging would sched a light...

Something else occured to me.  I guess I'm too much used to run the
current snapshots, rather than the current release version of Cygwin.

Probably the file-in-use stuff is not really your problem.  There's
another problem which is this:  If the directory you want to remove is
the CWD of a Windows process, then removing the dir fails.  The reason
is that the CWD handle of a Windows process is opened without the
FILE_SHARE_DELETE sahring mode set.  So, any try to rename or remove
that dir will fail.

For Cygwin 1.7.7, this is also true for Cygwin processes.  There was
that handle problem with Cygwin's CWD handling on Vista and later which
has been discussed on this list between August and October.  Since we
had no way to fix this problem at this point, Cygwin 1.7.7 reverted to
the old Cygwin 1.5 behaviour to use the Win32 function SetCurrentDirectory
to set the CWD.  With obvious results.

In the meantime John Carey was so kind to dive into the OS and found a
solution to replicate Vista's CWD handling so that Cygwin 1.7.8 will
again be able to remove directories which are the CWD of any Cygwin
process.  The problem with native, non-Cygwin processes holding a
CWD handle to this directory will of course persist.

So, here's the question:  Did you try a recent Cygwin snapshot from
http://cygwin.com/snapshots/?  Perhaps it fixes your problem.


Corinna

-- 
Corinna Vinschen                  Please, send mails regarding Cygwin to
Cygwin Project Co-Leader          cygwin AT cygwin DOT com
Red Hat

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