systemd/SOURCES/0029-udev-node-add-random-delay-on-conflict-in-updating-d.patch

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2021-11-04 00:51:05 +00:00
From c484f91a87679fb26342408f20e7bdddf316f5a0 Mon Sep 17 00:00:00 2001
From: Yu Watanabe <watanabe.yu+github@gmail.com>
Date: Wed, 1 Sep 2021 04:34:48 +0900
Subject: [PATCH] udev-node: add random delay on conflict in updating device
node symlink
To make multiple workers not update the same device node symlink
simultaneously.
(cherry picked from commit 0063fa23a1384dd4385d03b568dc629916b7e72a)
Related: #1977994
---
src/udev/udev-node.c | 12 ++++++++++++
1 file changed, 12 insertions(+)
diff --git a/src/udev/udev-node.c b/src/udev/udev-node.c
index 2e7df899e4..675e6ce313 100644
--- a/src/udev/udev-node.c
+++ b/src/udev/udev-node.c
@@ -20,12 +20,14 @@
#include "mkdir.h"
#include "parse-util.h"
#include "path-util.h"
+#include "random-util.h"
#include "selinux-util.h"
#include "smack-util.h"
#include "stat-util.h"
#include "stdio-util.h"
#include "string-util.h"
#include "strxcpyx.h"
+#include "time-util.h"
#include "udev-node.h"
#include "user-util.h"
@@ -33,6 +35,8 @@
#define LINK_UPDATE_MAX_RETRIES 128
#define CREATE_STACK_LINK_MAX_RETRIES 128
#define UPDATE_TIMESTAMP_MAX_RETRIES 128
+#define MAX_RANDOM_DELAY (250 * USEC_PER_MSEC)
+#define MIN_RANDOM_DELAY ( 50 * USEC_PER_MSEC)
#define UDEV_NODE_HASH_KEY SD_ID128_MAKE(b9,6a,f1,ce,40,31,44,1a,9e,19,ec,8b,ae,f3,e3,2f)
static int create_symlink(const char *target, const char *slink) {
@@ -447,6 +451,14 @@ static int link_update(sd_device *dev, const char *slink_in, bool add) {
_cleanup_free_ char *target = NULL;
struct stat st1 = {}, st2 = {};
+ if (i > 0) {
+ usec_t delay = MIN_RANDOM_DELAY + random_u64_range(MAX_RANDOM_DELAY - MIN_RANDOM_DELAY);
+
+ log_device_debug(dev, "Directory %s was updated, retrying to update devlink %s after %s.",
+ dirname, slink, FORMAT_TIMESPAN(delay, USEC_PER_MSEC));
+ (void) usleep(delay);
+ }
+
if (stat(dirname, &st1) < 0 && errno != ENOENT)
return log_device_debug_errno(dev, errno, "Failed to stat %s: %m", dirname);