Re: [PATCH 6/9] mnt: simplify ns_common_init() handling

On Thu 18-09-25 10:15:01, Christian Brauner wrote:

On Wed, Sep 17, 2025 at 06:45:11PM +0200, Jan Kara wrote:

quoted

On Wed 17-09-25 12:28:05, Christian Brauner wrote:

quoted

Assign the reserved MNT_NS_ANON_INO sentinel to anonymous mount
namespaces and cleanup the initial mount ns allocation. This is just a
preparatory patch and the ns->inum check in ns_common_init() will be
dropped in the next patch.

Signed-off-by: Christian Brauner <brauner@kernel.org>

...

quoted

---
 fs/namespace.c    | 7 ++++---
 kernel/nscommon.c | 2 +-
 2 files changed, 5 insertions(+), 4 deletions(-)

diff --git a/fs/namespace.c b/fs/namespace.c
index c8251545d57e..09e4ecd44972 100644
--- a/fs/namespace.c
+++ b/fs/namespace.c

@@ -4104,6 +4104,8 @@ static struct mnt_namespace *alloc_mnt_ns(struct user_namespace *user_ns, bool a
 		return ERR_PTR(-ENOMEM);
 	}
 
+	if (anon)
+		new_ns->ns.inum = MNT_NS_ANON_INO;
 	ret = ns_common_init(&new_ns->ns, &mntns_operations, !anon);
 	if (ret) {
 		kfree(new_ns);

@@ -6020,10 +6022,9 @@ static void __init init_mount_tree(void)
 	if (IS_ERR(mnt))
 		panic("Can't create rootfs");
 
-	ns = alloc_mnt_ns(&init_user_ns, true);
+	ns = alloc_mnt_ns(&init_user_ns, false);
 	if (IS_ERR(ns))
 		panic("Can't allocate initial namespace");
-	ns->ns.inum = PROC_MNT_INIT_INO;
 	m = real_mount(mnt);
 	ns->root = m;
 	ns->nr_mounts = 1;

@@ -6037,7 +6038,7 @@ static void __init init_mount_tree(void)
 	set_fs_pwd(current->fs, &root);
 	set_fs_root(current->fs, &root);
 
-	ns_tree_add(ns);
+	ns_tree_add_raw(ns);

But we don't have ns->ns_id set by anything now? Or am I missing something?

It is set in alloc_mnt_ns() via ns_tree_gen_id(). :)
Unless I'm missing something.

Ah, right. Feel free to add:

Reviewed-by: Jan Kara <jack@suse.cz>

								Honza
-- 
Jan Kara [off-list ref]
SUSE Labs, CR