Fix dkms installation of deb packages created with Alien.

rpm/generic/zfs-dkms.spec.in

@@ -24,6 +24,7 @@ BuildRoot:      %{_tmppath}/%{name}-%{version}-%{release}-root-%(%{__id_u} -n)
 BuildArch:      noarch
 
 Requires:       dkms >= 2.2.0.3
+Requires(pre):  dkms >= 2.2.0.3
 Requires(post): dkms >= 2.2.0.3
 Requires(preun): dkms >= 2.2.0.3
 Requires:       gcc, make, perl, diffutils
@@ -68,9 +69,92 @@ fi
 %defattr(-,root,root)
 /usr/src/%{module}-%{version}
 
+%pre
+echo "Running pre installation script: $0. Parameters: $*"
+# We don't want any other versions lingering around in dkms.
+# Tests with 'dnf' showed that in case of reinstall, or upgrade
+#  the preun scriptlet removed the version we are trying to install.
+# Because of this, find all zfs dkms sources in /var/lib/dkms and
+#  remove them, if we find a matching version in dkms.
+
+dkms_root=/var/lib/dkms
+if [ -d ${dkms_root}/%{module} ]; then
+    cd ${dkms_root}/%{module}
+    for x in [[:digit:]]*; do
+        [ -d "$x" ] || continue
+        otherver="$x"
+        opath="${dkms_root}/%{module}/${otherver}"
+        if [ "$otherver" != %{version} ]; then
+            # This is a workaround for a broken 'dkms status', we caused in a previous version.
+            # One day it might be not needed anymore, but it does not hurt to keep it.
+            if dkms status -m %{module} -v "$otherver" 2>&1 | grep "${opath}/source/dkms.conf does not exist"
+            then
+                echo "ERROR: dkms status is broken!" >&2
+                if [ -L "${opath}/source" -a ! -d "${opath}/source" ]
+                then
+                    echo "Trying to fix it by removing the symlink: ${opath}/source" >&2
+                    echo "You should manually remove ${opath}" >&2
+                    rm -f "${opath}/source" || echo "Removal failed!" >&2
+                fi
+            fi
+            if [ `dkms status -m %{module} -v "$otherver" | grep -c %{module}` -gt 0 ]; then
+                echo "Removing old %{module} dkms modules version $otherver from all kernels."
+                dkms remove -m %{module} -v "$otherver" --all ||:
+            fi
+        fi
+    done
+fi
+
+# Uninstall this version of zfs dkms modules before installation of the package.
+if [ `dkms status -m %{module} -v %{version} | grep -c %{module}` -gt 0 ]; then
+    echo "Removing %{module} dkms modules version %{version} from all kernels."
+    dkms remove -m %{module} -v %{version} --all ||:
+fi
+
+%post
+echo "Running post installation script: $0. Parameters: $*"
+# Add the module to dkms, as reccommended in the dkms man page.
+# This is generally rpm specfic.
+# But this also may help, if we have a broken 'dkms status'.
+# Because, if the sources are available and only the symlink pointing
+#  to them is missing, this will resolve the situation
+echo "Adding %{module} dkms modules version %{version} to dkms."
+dkms add -m %{module} -v %{version} %{!?not_rpm:--rpm_safe_upgrade} ||:
+
+# After installing the package, dkms install this zfs version for the current kernel.
+# Force the overwriting of old modules to avoid diff warnings in dkms status.
+# Or in case of a downgrade to overwrite newer versions.
+# Or if some other backed up versions have been restored before.
+echo "Installing %{module} dkms modules version %{version} for the current kernel."
+dkms install --force -m %{module} -v %{version} ||:
+
 %preun
-dkms remove -m %{module} -v %{version} --all
+dkms_root="/var/lib/dkms/%{module}/%{version}"
+echo "Running pre uninstall script: $0. Parameters: $*"
+# In case of upgrade we do nothing. See above comment in pre hook.
+if [ "$1" = "1" -o "$1" = "upgrade" ] ; then
+    echo "This is an upgrade. Skipping pre uninstall action."
+    exit 0
+fi
+
+# Check if we uninstall the package. In that case remove the dkms modules.
+# '0' is the value for the first parameter for rpm packages.
+# 'remove' or 'purge' are the possible names for deb packages.
+if [ "$1" = "0" -o "$1" = "remove" -o "$1" = "purge" ] ; then
+    if [ `dkms status -m %{module} -v %{version} | grep -c %{module}` -gt 0 ]; then
+        echo "Removing %{module} dkms modules version %{version} from all kernels."
+        dkms remove -m %{module} -v %{version} --all %{!?not_rpm:--rpm_safe_upgrade} && exit 0
+    fi
+    # If removing the modules failed, it might be because of the broken 'dkms status'.
+    if dkms status -m %{module} -v %{version} 2>&1 | grep "${dkms_root}/source/dkms.conf does not exist"
+    then
+        echo "ERROR: dkms status is broken!" >&2
+        echo "You should manually remove ${dkms_root}" >&2
+        echo "WARNING: installed modules in /lib/modules/`uname -r`/extra could not be removed automatically!" >&2
+    fi
+else
+    echo "Script parameter $1 did not match any removal condition."
+fi
 
-%posttrans
-/usr/lib/dkms/common.postinst %{module} %{version}
+exit 0