[Devel] [PATCH RHEL7 COMMIT] ve/net: Don't skip device_rename() for non-root Container netns

[Konstantin Khorenko]

The commit is pushed to "branch-rh7-3.10.0-1160.83.1.vz7.194.x-ovz" and will appear at https://src.openvz.org/scm/ovz/vzkernel.git
after rh7-3.10.0-1160.83.1.vz7.194.4
------>
commit 6e89993f44b2715942f2da8ee0d6f7757c5a594b
Author: Pavel Tikhomirov <ptikhomirov at virtuozzo.com>
Date:   Wed Feb 22 18:59:58 2023 +0800

    ve/net: Don't skip device_rename() for non-root Container netns
    
    This patch effectively reverts the commit:
      c6ac86bac9ce ("ve/net: allow to rename devices in non-ve namespaces")
    
    The patch says that it allows to rename devices, but instead it skips
    call to device_rename() for non-root netnses of the container.
    Ending up with not renamed sysfs link for the renamed device.
    
    And if such inconsistent device with different device name and sysfs
    name is moved to root netns of Container the systemd-udevd gets an event
    notification about it with mixed names.
    
    Systemd obviousely does not expect this and goes mad if at the same time
    old moved device name intersects with some other device name in root
    netns of Container, thus systemd disables this other device (e.g. eth0
    and breaks Container network).
    
    The original patch from vz6
      diff-ve-net-allow-to-rename-devices-in-non-ve-namespaces
    seems just to be a crutch for
      diff-ve-vedev-dont-call-netdev_fixup_sysfs-if-device_add-was-not-called
    so that sysfs entries of vedev don't break on netns creation.
    
    But as we don't have the latter (in vz7 device cgroups eliminated all
    crunches of that kind - https://jira.sw.ru/browse/PSBM-17918)
    now we also don't need the former.
    
    https://jira.sw.ru/browse/PSBM-145324
    
    Signed-off-by: Pavel Tikhomirov <ptikhomirov at virtuozzo.com>
---
 net/core/dev.c | 13 +++++--------
 1 file changed, 5 insertions(+), 8 deletions(-)

diff --git a/net/core/dev.c b/net/core/dev.c
index ec3e2d31c203..addd254c9c3c 100644
--- a/net/core/dev.c
+++ b/net/core/dev.c
@@ -1196,14 +1196,11 @@ int dev_change_name(struct net_device *dev, const char *newname)
 	}
 
 rollback:
-	if (!dev_net(dev)->owner_ve->ve_netns ||
-	    dev_net(dev)->owner_ve->ve_netns == dev->nd_net) {
-		ret = device_rename(&dev->dev, dev->name);
-		if (ret) {
-			memcpy(dev->name, oldname, IFNAMSIZ);
-			write_seqcount_end(&devnet_rename_seq);
-			return ret;
-		}
+	ret = device_rename(&dev->dev, dev->name);
+	if (ret) {
+		memcpy(dev->name, oldname, IFNAMSIZ);
+		write_seqcount_end(&devnet_rename_seq);
+		return ret;
 	}
 
 	write_seqcount_end(&devnet_rename_seq);