Unverified Commit cd267cde authored by Christian Brauner's avatar Christian Brauner
Browse files

Merge patch series "nsfs: expose the stable inode numbers in a public header" 

Christian Brauner <brauner@kernel.org> says:

Userspace heavily relies on the root inode numbers for namespaces to
identify the initial namespaces. That's already a hard dependency. So we
cannot change that anymore. Move the initial inode numbers to a public
header and align the only two namespaces that currently don't do that
with all the other namespaces.

* patches from https://lore.kernel.org/20250606-work-nsfs-v1-0-b8749c9a8844@kernel.org:
  mntns: use stable inode number for initial mount ns
  netns: use stable inode number for initial mount ns
  nsfs: move root inode number to uapi

Link: https://lore.kernel.org/20250606-work-nsfs-v1-0-b8749c9a8844@kernel.org


Signed-off-by: default avatarChristian Brauner <brauner@kernel.org>
parents 19272b37 7f4f2291

fs/namespace.c

+3 −1
Original line number Diff line number Diff line
@@ -6203,9 +6203,11 @@ static void __init init_mount_tree(void) 
	if (IS_ERR(mnt))

		panic("Can't create rootfs");



	ns = alloc_mnt_ns(&init_user_ns, false);

	ns = alloc_mnt_ns(&init_user_ns, true);

	if (IS_ERR(ns))

		panic("Can't allocate initial namespace");

	ns->seq = atomic64_inc_return(&mnt_ns_seq);

	ns->ns.inum = PROC_MNT_INIT_INO;

	m = real_mount(mnt);

	ns->root = m;

	ns->nr_mounts = 1;

include/linux/proc_ns.h

+9 −6
Original line number Diff line number Diff line
@@ -6,6 +6,7 @@ 
#define _LINUX_PROC_NS_H



#include <linux/ns_common.h>

#include <uapi/linux/nsfs.h>



struct pid_namespace;

struct nsset;
@@ -40,12 +41,14 @@ extern const struct proc_ns_operations timens_for_children_operations; 
 */

enum {

	PROC_ROOT_INO		= 1,

	PROC_IPC_INIT_INO	= 0xEFFFFFFFU,

	PROC_UTS_INIT_INO	= 0xEFFFFFFEU,

	PROC_USER_INIT_INO	= 0xEFFFFFFDU,

	PROC_PID_INIT_INO	= 0xEFFFFFFCU,

	PROC_CGROUP_INIT_INO	= 0xEFFFFFFBU,

	PROC_TIME_INIT_INO	= 0xEFFFFFFAU,

	PROC_IPC_INIT_INO	= IPC_NS_INIT_INO,

	PROC_UTS_INIT_INO	= UTS_NS_INIT_INO,

	PROC_USER_INIT_INO	= USER_NS_INIT_INO,

	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,

	PROC_MNT_INIT_INO	= MNT_NS_INIT_INO,

};



#ifdef CONFIG_PROC_FS

include/uapi/linux/nsfs.h

+11 −0
Original line number Diff line number Diff line
@@ -42,4 +42,15 @@ struct mnt_ns_info { 
/* Get previous namespace. */

#define NS_MNT_GET_PREV		_IOR(NSIO, 12, struct mnt_ns_info)



enum init_ns_ino {

	IPC_NS_INIT_INO		= 0xEFFFFFFFU,

	UTS_NS_INIT_INO		= 0xEFFFFFFEU,

	USER_NS_INIT_INO	= 0xEFFFFFFDU,

	PID_NS_INIT_INO		= 0xEFFFFFFCU,

	CGROUP_NS_INIT_INO	= 0xEFFFFFFBU,

	TIME_NS_INIT_INO	= 0xEFFFFFFAU,

	NET_NS_INIT_INO		= 0xEFFFFFF9U,

	MNT_NS_INIT_INO		= 0xEFFFFFF8U,

};



#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);

}