[Xen-changelog] [xen master] tools/xendomains: Create lockfile on start unconditionally

[patchbot@xxxxxxx]

commit 1c7fa3dc039487d18ad0c6fb6b773c831dca5e5d
Author:     George Dunlap <george.dunlap@xxxxxxxxxx>
AuthorDate: Wed May 11 12:14:45 2016 +0100
Commit:     Wei Liu <wei.liu2@xxxxxxxxxx>
CommitDate: Wed May 11 15:40:00 2016 +0100

    tools/xendomains: Create lockfile on start unconditionally
    
    At the moment, the xendomains init script will only create a lockfile
    if when started, it actually does something -- either tries to restore
    a previously saved domain as a result of XENDOMAINS_RESTORE, or tries
    to create a domain as a result of XENDOMAINS_AUTO.
    
    RedHat-based SYSV init systems try to only call "${SERVICE} shutdown"
    on systems which actually have an actively running component; and they
    use the existence of /var/lock/subsys/${SERVICE} to determine which
    systems are running.
    
    This means that at the moment, on RedHat-based SYSV systems (such as
    CentOS 6), if you enable xendomains, and have XENDOMAINS_RESTORE set
    to "true", but don't happen to start a VM, then your running VMs will
    not be suspended on shutdown.
    
    Since the lockfile doesn't really have any other effect than to
    prevent duplicate starting, just create it unconditionally every time
    we start the xendomains script.
    
    The other option would have been to touch the lockfile if
    XENDOMAINS_RESTORE was true regardless of whether there were any
    domains to be restored.  But this would mean that if you started with
    the xendomains script active but XENDOMAINS_RESTORE set to "false",
    and then changed it to "true", then xendomains would still not run the
    next time you shut down.  This seems to me to violate the principle of
    least surprise.
    
    Signed-off-by: George Dunlap <george.dunlap@xxxxxxxxxx>
    Acked-by: Wei Liu <wei.liu2@xxxxxxxxxx>
    Acked-by: Olaf Hering <olaf@xxxxxxxxx>
    Release-acked-by: Wei Liu <wei.liu2@xxxxxxxxxx>
---
 tools/hotplug/Linux/xendomains.in | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/tools/hotplug/Linux/xendomains.in 
b/tools/hotplug/Linux/xendomains.in
index 727cd42..334d244 100644
--- a/tools/hotplug/Linux/xendomains.in
+++ b/tools/hotplug/Linux/xendomains.in
@@ -255,12 +255,13 @@ start()
        return;
     fi
 
+    mkdir -p $(dirname "$LOCKFILE")
+    touch $LOCKFILE
+
     saved_domains=" "
     if [ "$XENDOMAINS_RESTORE" = "true" ] &&
        contains_something "$XENDOMAINS_SAVE"
     then
-       mkdir -p $(dirname "$LOCKFILE")
-       touch $LOCKFILE
        echo -n "Restoring Xen domains:"
        saved_domains=`ls $XENDOMAINS_SAVE`
         for dom in $XENDOMAINS_SAVE/*; do
@@ -286,7 +287,6 @@ start()
 
     if contains_something "$XENDOMAINS_AUTO"
     then
-       touch $LOCKFILE
        echo -n "Starting auto Xen domains:"
        # We expect config scripts for auto starting domains to be in
        # XENDOMAINS_AUTO - they could just be symlinks to files elsewhere
--
generated by git-patchbot for /home/xen/git/xen.git#master

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