Unverified Commit 9b0240b3 authored by Christian Brauner's avatar Christian Brauner
Browse files

netns: use stable inode number for initial mount ns 

Apart from the network and mount namespace all other namespaces expose a
stable inode number and userspace has been relying on that for a very
long time now. It's very much heavily used API. Align the network
namespace and use a stable inode number from the reserved procfs inode
number space so this is consistent across all namespaces.

Link: https://lore.kernel.org/20250606-work-nsfs-v1-2-b8749c9a8844@kernel.org


Reviewed-by: default avatarJakub Kicinski <kuba@kernel.org>
Signed-off-by: default avatarChristian Brauner <brauner@kernel.org>
parent 6a9e2fb1

include/linux/proc_ns.h

+1 −0
Original line number Diff line number Diff line
@@ -47,6 +47,7 @@ enum { 
	PROC_PID_INIT_INO	= PID_NS_INIT_INO,

	PROC_CGROUP_INIT_INO	= CGROUP_NS_INIT_INO,

	PROC_TIME_INIT_INO	= TIME_NS_INIT_INO,

	PROC_NET_INIT_INO	= NET_NS_INIT_INO,

};



#ifdef CONFIG_PROC_FS

include/uapi/linux/nsfs.h

+1 −0
Original line number Diff line number Diff line
@@ -49,6 +49,7 @@ enum init_ns_ino { 
	PID_NS_INIT_INO		= 0xEFFFFFFCU,

	CGROUP_NS_INIT_INO	= 0xEFFFFFFBU,

	TIME_NS_INIT_INO	= 0xEFFFFFFAU,

	NET_NS_INIT_INO		= 0xEFFFFFF9U,

};



#endif /* __LINUX_NSFS_H */

net/core/net_namespace.c

+8 −0
Original line number Diff line number Diff line
@@ -796,11 +796,19 @@ static __net_init int net_ns_net_init(struct net *net) 
#ifdef CONFIG_NET_NS

	net->ns.ops = &netns_operations;

#endif

	if (net == &init_net) {

		net->ns.inum = PROC_NET_INIT_INO;

		return 0;

	}

	return ns_alloc_inum(&net->ns);

}



static __net_exit void net_ns_net_exit(struct net *net)

{

	/*

	 * Initial network namespace doesn't exit so we don't need any

	 * special checks here.

	 */

	ns_free_inum(&net->ns);

}