[Xen-devel] [PATCH v1] tools/hotplug: convert proc-xen.mount to proc-xen.service

[Olaf Hering <olaf@xxxxxxxxx>]

An upcoming change in systemd will mount xenfs right away, along with
all other system mounts. This improves the detection of the
virtualization environment, which is currently racy. Some parts of
systemd rely on the presence of /proc/xen/capabilities, which will only
exist if xenfs is mounted. Since xenfs is mounted by the proc-xen.mount
unit, it will be processed very late. Other units may be processed
earlier, and if they make use of ConditionVirtualization*= failures may
occour.

Unfortunately mounting xenfs by systemd as an API filesystem will lead
to errors when proc-xen.mount is processed. Since that mount point
already exists the unit is considered as failed, and other units that
depend on proc-xen.mount will not start. To avoid this the existing
proc-xen.mount will be converted into proc-xen.service, which just
mounts xenfs manually. All dependencies are updated by this change.

The existing conditionals in proc-xen.mount will prevent failures with
existing systemd based installations:
ConditionPathExists=!/proc/xen/capabilities will prevent execution with
a new systemd that mounts xenfs. And this conditional, in combination
with ConditionPathExists=/proc/xen, will trigger execution with an old
systemd.

An absolute path to the mount binary has to be used. /bin/mount is
expected to be universally available, nowaways it is a symlink to
/usr/bin/mount.

Signed-off-by: Olaf Hering <olaf@xxxxxxxxx>
---

based on 4.10.0-rc2
Please run autogen.sh:

 tools/configure.ac                                                | 2 +-
 tools/hotplug/Linux/systemd/Makefile                              | 6 +++---
 .../Linux/systemd/{proc-xen.mount.in => proc-xen.service.in}      | 8 ++++----
 tools/hotplug/Linux/systemd/var-lib-xenstored.mount.in            | 4 ++--
 tools/hotplug/Linux/systemd/xen-init-dom0.service.in              | 4 ++--
 tools/hotplug/Linux/systemd/xen-qemu-dom0-disk-backend.service.in | 4 ++--
 tools/hotplug/Linux/systemd/xen-watchdog.service.in               | 4 ++--
 tools/hotplug/Linux/systemd/xenconsoled.service.in                | 4 ++--
 tools/hotplug/Linux/systemd/xendomains.service.in                 | 4 ++--
 tools/hotplug/Linux/systemd/xendriverdomain.service.in            | 4 ++--
 tools/hotplug/Linux/systemd/xenstored.service.in                  | 6 +++---
 11 files changed, 25 insertions(+), 25 deletions(-)
 rename tools/hotplug/Linux/systemd/{proc-xen.mount.in => proc-xen.service.in} 
(60%)

diff --git a/tools/configure.ac b/tools/configure.ac
index d1a3a78d87..7b18421fa0 100644
--- a/tools/configure.ac
+++ b/tools/configure.ac
@@ -441,7 +441,7 @@ AX_AVAILABLE_SYSTEMD()
 
 AS_IF([test "x$systemd" = "xy"], [
     AC_CONFIG_FILES([
-    hotplug/Linux/systemd/proc-xen.mount
+    hotplug/Linux/systemd/proc-xen.service
     hotplug/Linux/systemd/var-lib-xenstored.mount
     hotplug/Linux/systemd/xen-init-dom0.service
     hotplug/Linux/systemd/xen-qemu-dom0-disk-backend.service
diff --git a/tools/hotplug/Linux/systemd/Makefile 
b/tools/hotplug/Linux/systemd/Makefile
index a5d41d86ef..855ff3747f 100644
--- a/tools/hotplug/Linux/systemd/Makefile
+++ b/tools/hotplug/Linux/systemd/Makefile
@@ -3,10 +3,10 @@ include $(XEN_ROOT)/tools/Rules.mk
 
 XEN_SYSTEMD_MODULES = xen.conf
 
-XEN_SYSTEMD_MOUNT =  proc-xen.mount
-XEN_SYSTEMD_MOUNT += var-lib-xenstored.mount
+XEN_SYSTEMD_MOUNT  = var-lib-xenstored.mount
 
-XEN_SYSTEMD_SERVICE  = xenstored.service
+XEN_SYSTEMD_SERVICE  = proc-xen.service
+XEN_SYSTEMD_SERVICE += xenstored.service
 XEN_SYSTEMD_SERVICE += xenconsoled.service
 XEN_SYSTEMD_SERVICE += xen-qemu-dom0-disk-backend.service
 XEN_SYSTEMD_SERVICE += xendomains.service
diff --git a/tools/hotplug/Linux/systemd/proc-xen.mount.in 
b/tools/hotplug/Linux/systemd/proc-xen.service.in
similarity index 60%
rename from tools/hotplug/Linux/systemd/proc-xen.mount.in
rename to tools/hotplug/Linux/systemd/proc-xen.service.in
index 64ebe7f9b1..76f0097b75 100644
--- a/tools/hotplug/Linux/systemd/proc-xen.mount.in
+++ b/tools/hotplug/Linux/systemd/proc-xen.service.in
@@ -4,7 +4,7 @@ ConditionPathExists=/proc/xen
 ConditionPathExists=!/proc/xen/capabilities
 RefuseManualStop=true
 
-[Mount]
-What=xenfs
-Where=/proc/xen
-Type=xenfs
+[Service]
+Type=oneshot
+RemainAfterExit=true
+ExecStart=/bin/mount -t xenfs xenfs /proc/xen
diff --git a/tools/hotplug/Linux/systemd/var-lib-xenstored.mount.in 
b/tools/hotplug/Linux/systemd/var-lib-xenstored.mount.in
index 11a7d50edc..5d171f82e8 100644
--- a/tools/hotplug/Linux/systemd/var-lib-xenstored.mount.in
+++ b/tools/hotplug/Linux/systemd/var-lib-xenstored.mount.in
@@ -1,7 +1,7 @@
 [Unit]
 Description=mount xenstore file system
-Requires=proc-xen.mount
-After=proc-xen.mount
+Requires=proc-xen.service
+After=proc-xen.service
 ConditionPathExists=/proc/xen/capabilities
 RefuseManualStop=true
 
diff --git a/tools/hotplug/Linux/systemd/xen-init-dom0.service.in 
b/tools/hotplug/Linux/systemd/xen-init-dom0.service.in
index 3befadcea3..c560fbe1b7 100644
--- a/tools/hotplug/Linux/systemd/xen-init-dom0.service.in
+++ b/tools/hotplug/Linux/systemd/xen-init-dom0.service.in
@@ -1,7 +1,7 @@
 [Unit]
 Description=xen-init-dom0, initialise Dom0 configuration (xenstore nodes, JSON 
configuration stub)
-Requires=xenstored.service proc-xen.mount
-After=xenstored.service proc-xen.mount
+Requires=xenstored.service proc-xen.service
+After=xenstored.service proc-xen.service
 ConditionPathExists=/proc/xen/capabilities
 
 [Service]
diff --git a/tools/hotplug/Linux/systemd/xen-qemu-dom0-disk-backend.service.in 
b/tools/hotplug/Linux/systemd/xen-qemu-dom0-disk-backend.service.in
index f56775bc87..1b95104823 100644
--- a/tools/hotplug/Linux/systemd/xen-qemu-dom0-disk-backend.service.in
+++ b/tools/hotplug/Linux/systemd/xen-qemu-dom0-disk-backend.service.in
@@ -1,7 +1,7 @@
 [Unit]
 Description=qemu for xen dom0 disk backend
-Requires=proc-xen.mount xenstored.service
-After=proc-xen.mount xenstored.service xenconsoled.service
+Requires=proc-xen.service xenstored.service
+After=proc-xen.service xenstored.service xenconsoled.service
 Before=xendomains.service libvirtd.service libvirt-guests.service
 RefuseManualStop=true
 ConditionPathExists=/proc/xen/capabilities
diff --git a/tools/hotplug/Linux/systemd/xen-watchdog.service.in 
b/tools/hotplug/Linux/systemd/xen-watchdog.service.in
index 1eecd2a616..3b9aff5e3b 100644
--- a/tools/hotplug/Linux/systemd/xen-watchdog.service.in
+++ b/tools/hotplug/Linux/systemd/xen-watchdog.service.in
@@ -1,7 +1,7 @@
 [Unit]
 Description=Xen-watchdog - run xen watchdog daemon
-Requires=proc-xen.mount
-After=proc-xen.mount xendomains.service
+Requires=proc-xen.service
+After=proc-xen.service xendomains.service
 ConditionPathExists=/proc/xen/capabilities
 
 [Service]
diff --git a/tools/hotplug/Linux/systemd/xenconsoled.service.in 
b/tools/hotplug/Linux/systemd/xenconsoled.service.in
index 8e333b114e..2a01262ecd 100644
--- a/tools/hotplug/Linux/systemd/xenconsoled.service.in
+++ b/tools/hotplug/Linux/systemd/xenconsoled.service.in
@@ -1,7 +1,7 @@
 [Unit]
 Description=Xenconsoled - handles logging from guest consoles and hypervisor
-Requires=proc-xen.mount xenstored.service
-After=proc-xen.mount xenstored.service
+Requires=proc-xen.service xenstored.service
+After=proc-xen.service xenstored.service
 ConditionPathExists=/proc/xen/capabilities
 
 [Service]
diff --git a/tools/hotplug/Linux/systemd/xendomains.service.in 
b/tools/hotplug/Linux/systemd/xendomains.service.in
index c7bfb61eb4..f89460da35 100644
--- a/tools/hotplug/Linux/systemd/xendomains.service.in
+++ b/tools/hotplug/Linux/systemd/xendomains.service.in
@@ -1,7 +1,7 @@
 [Unit]
 Description=Xendomains - start and stop guests on boot and shutdown
-Requires=proc-xen.mount xenstored.service
-After=proc-xen.mount xenstored.service xenconsoled.service 
xen-init-dom0.service
+Requires=proc-xen.service xenstored.service
+After=proc-xen.service xenstored.service xenconsoled.service 
xen-init-dom0.service
 After=network-online.target
 After=remote-fs.target
 ConditionPathExists=/proc/xen/capabilities
diff --git a/tools/hotplug/Linux/systemd/xendriverdomain.service.in 
b/tools/hotplug/Linux/systemd/xendriverdomain.service.in
index c39ec04182..c3b0a32147 100644
--- a/tools/hotplug/Linux/systemd/xendriverdomain.service.in
+++ b/tools/hotplug/Linux/systemd/xendriverdomain.service.in
@@ -1,7 +1,7 @@
 [Unit]
 Description=Xen driver domain device daemon
-Requires=proc-xen.mount
-After=proc-xen.mount
+Requires=proc-xen.service
+After=proc-xen.service
 ConditionVirtualization=xen
 
 [Service]
diff --git a/tools/hotplug/Linux/systemd/xenstored.service.in 
b/tools/hotplug/Linux/systemd/xenstored.service.in
index 80c1d408a5..da1f197d11 100644
--- a/tools/hotplug/Linux/systemd/xenstored.service.in
+++ b/tools/hotplug/Linux/systemd/xenstored.service.in
@@ -1,7 +1,7 @@
 [Unit]
 Description=The Xen xenstore
-Requires=proc-xen.mount var-lib-xenstored.mount
-After=proc-xen.mount var-lib-xenstored.mount
+Requires=proc-xen.service var-lib-xenstored.mount
+After=proc-xen.service var-lib-xenstored.mount
 Before=libvirtd.service libvirt-guests.service
 RefuseManualStop=true
 ConditionPathExists=/proc/xen/capabilities
@@ -15,5 +15,5 @@ ExecStart=@XEN_SCRIPT_DIR@/launch-xenstore
 
 [Install]
 WantedBy=multi-user.target
-Also=proc-xen.mount
+Also=proc-xen.service
 Also=var-lib-xenstored.mount

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