From 47be6344bb314a81da30e6d24cdad52c548862ec Mon Sep 17 00:00:00 2001
From: Michael Biebl <biebl@debian.org>
Date: Thu, 18 Jul 2013 01:04:07 +0200
Subject: [PATCH] Revert "udev: network device renaming - immediately give up
 if the target name isn't available"

This reverts commit 97595710b77aa162ca5e20da57d0a1ed7355eaad.

We need to keep supporting systems with 75-persistent-net-generator.rules
generated names for a while after switching to net.ifnames. Re-apply this old
hack to make the renaming less likely to fail.

Gbp-Pq: Topic debian
Gbp-Pq: Name Revert-udev-network-device-renaming-immediately-give.patch
---
 src/udev/udev-event.c | 41 ++++++++++++++++++++++++++++++++++++++---
 1 file changed, 38 insertions(+), 3 deletions(-)

diff --git a/src/udev/udev-event.c b/src/udev/udev-event.c
index fd8406d9..14c1d26d 100644
--- a/src/udev/udev-event.c
+++ b/src/udev/udev-event.c
@@ -819,18 +819,53 @@ static int rename_netif(struct udev_event *event) {
         char name[IFNAMSIZ];
         const char *oldname;
         int r;
+        int loop;
 
         oldname = udev_device_get_sysname(dev);
 
         strscpy(name, IFNAMSIZ, event->name);
 
+        r = rtnl_set_link_name(&event->rtnl, udev_device_get_ifindex(dev), name);
+        if (r >= 0) {
+                log_debug("renamed network interface %s to %s\n", oldname, name);
+                goto out;
+        }
+
+        /* keep trying if the destination interface name already exists */
+        if (r != -EEXIST)
+                goto out;
+
+        /* free our own name, another process may wait for us */
+        snprintf(name, IFNAMSIZ, "rename%u", udev_device_get_ifindex(dev));
         r = rtnl_set_link_name(&event->rtnl, udev_device_get_ifindex(dev), name);
         if (r < 0)
-                return log_error_errno(r, "Error changing net interface name '%s' to '%s': %m", oldname, name);
+                  goto out;
 
-        log_debug("renamed network interface '%s' to '%s'", oldname, name);
+        /* log temporary name */
+        log_debug("renamed network interface %s to %s\n", oldname, name);
 
-        return 0;
+        /* wait a maximum of 90 seconds for our target to become available */
+        strscpy(name, IFNAMSIZ, event->name);
+        loop = 90 * 20;
+        while (loop--) {
+                const struct timespec duration = { 0, 1000 * 1000 * 1000 / 20 };
+
+                nanosleep(&duration, NULL);
+
+                r = rtnl_set_link_name(&event->rtnl, udev_device_get_ifindex(dev), name);
+                if (r >= 0) {
+                        log_debug("renamed network interface %s to %s\n", oldname, name);
+                        break;
+                }
+                if (r != -EEXIST)
+                        break;
+        }
+
+out:
+        if (r < 0)
+                log_error("error changing net interface name '%s' to '%s': %s",
+                          oldname, name, strerror(-r));
+        return r;
 }
 
 void udev_event_execute_rules(struct udev_event *event,
-- 
2.30.2