Public bug reported:

I am running Kubuntu 14.04.3 and I am connecting to a Strato Hidrive
WebDAV share with davfs2.  In fact, I am still looking for some small,
free cloud drive for some private files, I do not care which one.  For
privacy reasons, I am mounting an encrypted EncFS on top of the cloud
drive.  My current test drive has only a few files, all well below 1
MiB. The Internet connection is quite OK at 16 Mbps.

I found that applications that use the davfs2 mount randomly freeze.
Example applications are Emacs, LibreOffice Writer and KDE's Dolphin.
There is no way to unfreeze them, and trying to unmount WebDAV share
fails, no matter what unmount flags (like lazy umount) I try.

My freeze symptoms are also described on the following pages:

  https://serverfault.com/questions/590696/forcefully-unmounting-
filesystem

  https://serverfault.com/questions/597733/a-mount-of-box-com-as-davfs2
-hangs-and-does-not-become-unstuck

  https://bugzilla.redhat.com/show_bug.cgi?id=895118

Is there a way to unfreeze the davfs2 mount, even if it means losing
WebDAV files? I do not want to restart the PC every time this happens.

Kubuntu 14.04.3 comes with davfs2 1.4.7, but I noticed that more recent
Ubuntu distributions have the newer version 1.5.2.

The upstream web site is at https://savannah.nongnu.org/projects/davfs2
and has no e-mail address or mailing list.  There is a bug report
system, but I am investigating and have yet no specific bug to report.
There is also a support ticket system, but tickets stay there years
marked as "in progress". I could not see anything about freezing, even
though it seems a rather common problem.

I managed to find a working e-mail address for the lone upstream
maintainer, Werner Baumann, and he did answer. He explained that
software tends to think that disk accesses cost nothing and very easily
overload the WebDAV server. File managers like Dolphin are especially
prone to this. The trouble is, a frozen Dolphin normally means that your
entire KDE desktop freezes.

However, I am seeing the freezing problem with Emacs opening a single
text file. Waiting for half an hour does not help. Emacs becomes then
the only frozen software on the computer, everything else still runs
fine.  When that happens, as soon as other software touches the WebDAV
share, it freezes too.

davfs2 has some kind of cache. I tried creating a ~/.davfs2/davfs2.conf
with these settings, but they did not help either:

  use_locks 0
  gui_optimize 1

The way it is now, davfs2 is unusable on Ubuntu, and actually damaging
for the whole desktop environment.

I am considering compiling the latest 1.5.2, but I do not want to
overwrite the system's default version. However, the README says that
'mount.davfs' will be installed with setuid root. Is there a way to
install this on my home directory and let it run without root
privileges? It is a FUSE thing after all. I would not want to overwrite
the system's /etc/davfs2/davfs2.conf, but use other copies instead, and
according to the README if you run mount.davfs it will overwrite the
system config files.

At first, I thought that maybe the server is not responding quickly.
There seems to be no way to adjust server timeouts in davfs2, so I could
not try lowering them.

I learnt that there are alternatives like fusedav and gvfs-mount. Do
they work any better?

** Affects: davfs2 (Ubuntu)
     Importance: Undecided
         Status: New

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https://bugs.launchpad.net/bugs/1538445

Title:
  davfs2 often freezes any program that uses it

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