[Devel] [PATCH VZ10 3/8] ve/mntns: thread owning ve through alloc_mnt_ns/copy_mnt_ns

[Pavel Tikhomirov]

Add new_ve parameter to alloc_mnt_ns() and copy_mnt_ns(). NULL preserves
the existing behaviour of taking current ve via get_exec_env().

This will be used to derive correct ownership of newly created mounts in
case of simultaneous creation of new ve namespace and mount namespace,
were we would like new mounts to have the new ve as an owner.

There is no change in behaviour yet: create_new_namespaces() still uses
NULL.

https://virtuozzo.atlassian.net/browse/VSTOR-129744
Signed-off-by: Pavel Tikhomirov <ptikhomirov at virtuozzo.com>
Feature: ve: ve generic structures
---
 fs/namespace.c                | 21 ++++++++++++---------
 include/linux/mnt_namespace.h |  4 +++-
 kernel/nsproxy.c              |  3 ++-
 3 files changed, 17 insertions(+), 11 deletions(-)

diff --git a/fs/namespace.c b/fs/namespace.c
index ba2cee9a6db1..865635366fd7 100644
--- a/fs/namespace.c
+++ b/fs/namespace.c
@@ -2239,7 +2239,8 @@ struct vfsmount *collect_mounts(const struct path *path)
 }
 
 static void free_mnt_ns(struct mnt_namespace *);
-static struct mnt_namespace *alloc_mnt_ns(struct user_namespace *, bool);
+static struct mnt_namespace *alloc_mnt_ns(struct user_namespace *, bool,
+					  struct ve_struct *);
 
 void dissolve_on_fput(struct vfsmount *mnt)
 {
@@ -2867,7 +2868,7 @@ static int do_loopback(struct path *path, const char *old_name,
 static struct file *open_detached_copy(struct path *path, bool recursive)
 {
 	struct user_namespace *user_ns = current->nsproxy->mnt_ns->user_ns;
-	struct mnt_namespace *ns = alloc_mnt_ns(user_ns, true);
+	struct mnt_namespace *ns = alloc_mnt_ns(user_ns, true, NULL);
 	struct mount *mnt, *p;
 	struct file *file;
 
@@ -4163,7 +4164,8 @@ static void free_mnt_ns(struct mnt_namespace *ns)
  */
 static atomic64_t mnt_ns_seq = ATOMIC64_INIT(1);
 
-static struct mnt_namespace *alloc_mnt_ns(struct user_namespace *user_ns, bool anon)
+static struct mnt_namespace *alloc_mnt_ns(struct user_namespace *user_ns,
+					  bool anon, struct ve_struct *new_ve)
 {
 	struct mnt_namespace *new_ns;
 	struct ucounts *ucounts;
@@ -4203,14 +4205,15 @@ static struct mnt_namespace *alloc_mnt_ns(struct user_namespace *user_ns, bool a
 	new_ns->user_ns = get_user_ns(user_ns);
 	new_ns->ucounts = ucounts;
 #ifdef CONFIG_VE
-	new_ns->ve_owner = get_ve(get_exec_env());
+	new_ns->ve_owner = get_ve(new_ve ?: get_exec_env());
 #endif
 	return new_ns;
 }
 
 __latent_entropy
 struct mnt_namespace *copy_mnt_ns(unsigned long flags, struct mnt_namespace *ns,
-		struct user_namespace *user_ns, struct fs_struct *new_fs)
+		struct user_namespace *user_ns, struct fs_struct *new_fs,
+		struct ve_struct *new_ve)
 {
 	struct mnt_namespace *new_ns;
 	struct vfsmount *rootmnt = NULL, *pwdmnt = NULL;
@@ -4228,7 +4231,7 @@ struct mnt_namespace *copy_mnt_ns(unsigned long flags, struct mnt_namespace *ns,
 
 	old = ns->root;
 
-	new_ns = alloc_mnt_ns(user_ns, false);
+	new_ns = alloc_mnt_ns(user_ns, false, new_ve);
 	if (IS_ERR(new_ns))
 		return new_ns;
 
@@ -4304,7 +4307,7 @@ struct dentry *mount_subtree(struct vfsmount *m, const char *name)
 	struct path path;
 	int err;
 
-	ns = alloc_mnt_ns(&init_user_ns, true);
+	ns = alloc_mnt_ns(&init_user_ns, true, NULL);
 	if (IS_ERR(ns)) {
 		mntput(m);
 		return ERR_CAST(ns);
@@ -4483,7 +4486,7 @@ SYSCALL_DEFINE3(fsmount, int, fs_fd, unsigned int, flags,
 	 */
 	vfs_clean_context(fc);
 
-	ns = alloc_mnt_ns(current->nsproxy->mnt_ns->user_ns, true);
+	ns = alloc_mnt_ns(current->nsproxy->mnt_ns->user_ns, true, NULL);
 	if (IS_ERR(ns)) {
 		ret = PTR_ERR(ns);
 		goto err_path;
@@ -5794,7 +5797,7 @@ 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, false, NULL);
 	if (IS_ERR(ns))
 		panic("Can't allocate initial namespace");
 	m = real_mount(mnt);
diff --git a/include/linux/mnt_namespace.h b/include/linux/mnt_namespace.h
index 70b366b64816..61a26bc99813 100644
--- a/include/linux/mnt_namespace.h
+++ b/include/linux/mnt_namespace.h
@@ -10,9 +10,11 @@ struct mnt_namespace;
 struct fs_struct;
 struct user_namespace;
 struct ns_common;
+struct ve_struct;
 
 extern struct mnt_namespace *copy_mnt_ns(unsigned long, struct mnt_namespace *,
-		struct user_namespace *, struct fs_struct *);
+		struct user_namespace *, struct fs_struct *,
+		struct ve_struct *);
 extern void put_mnt_ns(struct mnt_namespace *ns);
 DEFINE_FREE(put_mnt_ns, struct mnt_namespace *, if (!IS_ERR_OR_NULL(_T)) put_mnt_ns(_T))
 extern struct ns_common *from_mnt_ns(struct mnt_namespace *);
diff --git a/kernel/nsproxy.c b/kernel/nsproxy.c
index 2827d4f277ad..12de23ec80bf 100644
--- a/kernel/nsproxy.c
+++ b/kernel/nsproxy.c
@@ -76,7 +76,8 @@ static struct nsproxy *create_new_namespaces(unsigned long flags,
 	if (!new_nsp)
 		return ERR_PTR(-ENOMEM);
 
-	new_nsp->mnt_ns = copy_mnt_ns(flags, tsk->nsproxy->mnt_ns, user_ns, new_fs);
+	new_nsp->mnt_ns = copy_mnt_ns(flags, tsk->nsproxy->mnt_ns, user_ns,
+				      new_fs, NULL);
 	if (IS_ERR(new_nsp->mnt_ns)) {
 		err = PTR_ERR(new_nsp->mnt_ns);
 		goto out_ns;
-- 
2.53.0