From: Matthias Kruk <m@m10k.eu>
Date: Sun, 6 Jun 2021 02:22:43 +0000 (+0900)
Subject: include/{mutex,wmutex}: Change mutexes back to the sleep-based approach
X-Git-Url: https://git.corax.cc/?a=commitdiff_plain;h=005ec83231e9ce90fd601fa34ac2585d13b008fd;p=toolbox

include/{mutex,wmutex}: Change mutexes back to the sleep-based approach

Using inotifywait to wait on a mutex does not work reliably when the mutex
is on an NFS and the processes synchronizing on it are running on different
machines.
This commit changes the implementations of mutex and wmutex back to use
sleep instead of inotifywait.
---

diff --git a/include/mutex.sh b/include/mutex.sh
index 4efd905..0bb71c2 100644
--- a/include/mutex.sh
+++ b/include/mutex.sh
@@ -24,14 +24,11 @@ mutex_lock() {
 	local -i timeout="$2"
 
 	while ! mutex_trylock "$lock"; do
-		# We can't inotifywait on symlinks. Which is
-		# fine because when the symlink is removed, the
-		# containing directory is changed. Hence, we can
-		# watch the containing directory instead.
-
-		if ! inotifywait -qq "${lock%/*}" -t "$timeout"; then
+		if (( --timeout < 0 )); then
 			return 1
 		fi
+
+		sleep 1
 	done
 
 	return 0
diff --git a/include/wmutex.sh b/include/wmutex.sh
index ff732bd..d4bcf99 100644
--- a/include/wmutex.sh
+++ b/include/wmutex.sh
@@ -24,9 +24,11 @@ wmutex_lock() {
 	local -i timeout="$2"
 
 	while ! wmutex_trylock "$lock"; do
-		if ! inotifywait -qq "${lock%/*}" -t "$timeout"; then
+		if (( --timeout < 0 )); then
 			return 1
 		fi
+
+		sleep 1
 	done
 
 	return 0