1 files changed, 45 insertions, 0 deletions
diff --git a/ctdb/config/debug_locks.sh b/ctdb/config/debug_locks.sh
new file mode 100644
index 00000000000..0dde8615245
--- /dev/null
+++ b/ctdb/config/debug_locks.sh
@@ -0,0 +1,45 @@
+#!/bin/sh
+
+# This script parses /proc/locks and finds the processes that are holding
+# locks on CTDB databases.  For all those processes the script dumps a
+# stack trace using gstack.
+#
+# This script can be used only if Samba is configured to use fcntl locks
+# rather than mutex locks.
+
+# Create sed expression to convert inodes to names
+sed_cmd=$( ls -li /var/ctdb/*.tdb.* /var/ctdb/persistent/*.tdb.* |
+	   sed -e "s#/var/ctdb[/persistent]*/\(.*\)#\1#" |
+	   awk '{printf "s#[0-9]*:[0-9]*:%s #%s #\n", $1, $10}' )
+
+# Parse /proc/locks and extract following information
+#    pid process_name tdb_name offsets [W]
+out=$( cat /proc/locks |
+    grep -F "POSIX  ADVISORY  WRITE" |
+    awk '{ if($2 == "->") { print $6, $7, $8, $9, "W" } else { print $5, $6, $7, $8 } }' |
+    while read pid rest ; do
+	pname=$(readlink /proc/$pid/exe)
+	echo $pid $pname $rest
+    done | sed -e "$sed_cmd" | grep "\.tdb" )
+
+if [ -n "$out" ]; then
+    # Log information about locks
+    echo "$out" | logger -t "ctdbd-lock"
+
+    # Find processes that are waiting for locks
+    dbs=$(echo "$out" | grep "W$" | awk '{print $3}')
+    all_pids=""
+    for db in $dbs ; do
+	pids=$(echo "$out" | grep -v "W$" | grep "$db" | grep -v ctdbd | awk '{print $1}')
+	all_pids="$all_pids $pids"
+    done
+    pids=$(echo $all_pids | sort -u)
+
+    # For each process waiting, log stack trace
+    for pid in $pids ; do
+	gstack $pid | logger -t "ctdbd-lock $pid"
+#	gcore -o /var/log/core-deadlock-ctdb $pid
+    done
+fi
+
+exit 0