From 2601e06512bce1434d7a89ba2034f32303837418 Mon Sep 17 00:00:00 2001
From: Donald Buczek <buczek@molgen.mpg.de>
Date: Fri, 17 Sep 2021 12:20:15 +0200
Subject: [PATCH 1/3] mx_flock: Don't unlock before close

We don't need to call flock(fd, LOCK_UN) for a file we are going to
close anyway, so don't do it.

This might make a difference if the lock fd was dupped into another fd.
---
 mx_flock.c | 4 ----
 1 file changed, 4 deletions(-)

diff --git a/mx_flock.c b/mx_flock.c
index ead5ae4d..ab9f3dba 100644
--- a/mx_flock.c
+++ b/mx_flock.c
@@ -149,10 +149,6 @@ int mx_funlock(struct mx_flock *lock)
     if (res < 0)
         mx_log_warning("unlink(): %m");
 
-    res = flock(lock->fd, LOCK_UN);
-    if (res < 0)
-        mx_log_warning("flock(): %m");
-
     _flock_close(lock);
     _flock_free(lock);
 

From 0be33f7050167371748a17f7b3036f54e5f3204b Mon Sep 17 00:00:00 2001
From: Donald Buczek <buczek@molgen.mpg.de>
Date: Fri, 17 Sep 2021 12:08:44 +0200
Subject: [PATCH 2/3] mx_flock: Add mx_funlock_nodelete

Add function to release the lock without removing the logfile. This is
useful for forked children, which inherited the lock and just need to
give it up.
---
 mx_flock.c | 7 +++++++
 mx_flock.h | 1 +
 2 files changed, 8 insertions(+)

diff --git a/mx_flock.c b/mx_flock.c
index ab9f3dba..ef4d3ede 100644
--- a/mx_flock.c
+++ b/mx_flock.c
@@ -155,6 +155,13 @@ int mx_funlock(struct mx_flock *lock)
     return res;
 }
 
+/* as above, but don't delete lock file
+ */
+void mx_funlock_nodelete(struct mx_flock *lock) {
+    _flock_close(lock);
+    _flock_free(lock);
+}
+
 void mx_flock_free(struct mx_flock *lock)
 {
     _flock_free(lock);
diff --git a/mx_flock.h b/mx_flock.h
index 34ab4e8d..9b632829 100644
--- a/mx_flock.h
+++ b/mx_flock.h
@@ -10,6 +10,7 @@ struct mx_flock {
 
 struct mx_flock *mx_flock(int operation, char *fmt, ...);
 int mx_funlock(struct mx_flock *lock);
+void mx_funlock_nodelete(struct mx_flock *lock);
 void mx_flock_free(struct mx_flock *lock);
 
 #endif

From b8fd11a9a48e1ab2b8c4c1c459ef8ae73d7fc89f Mon Sep 17 00:00:00 2001
From: Donald Buczek <buczek@molgen.mpg.de>
Date: Fri, 17 Sep 2021 12:23:47 +0200
Subject: [PATCH 3/3] mxqd: Unlock but do not delete lock file in reaper

The reaper inherits the locked lock file and needs to unlock it. Use
mx_funlock_nodelete instead of mx_funlock so that the lock file is not
removed.
---
 mxqd.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/mxqd.c b/mxqd.c
index b960426a..c858746f 100644
--- a/mxqd.c
+++ b/mxqd.c
@@ -1390,7 +1390,7 @@ unsigned long start_job(struct mxq_group_list *glist)
         job->host_pid = getpid();
 
         mx_log_debug("starting reaper process.");
-        mx_funlock(server->flock);
+        mx_funlock_nodelete(server->flock);
         server->flock = NULL;
         mx_mysql_finish(&server->mysql);