Store the sequence number of the mount namespace the anonymous mount
namespace has been created from. This information will be used in
follow-up patches.
Signed-off-by: Christian Brauner <brauner@xxxxxxxxxx>
---
fs/mount.h | 1 +
fs/namespace.c | 17 +++++++++++++++--
2 files changed, 16 insertions(+), 2 deletions(-)
diff --git a/fs/mount.h b/fs/mount.h
index ffb613cdfeee..820a79f1f735 100644
--- a/fs/mount.h
+++ b/fs/mount.h
@@ -20,6 +20,7 @@ struct mnt_namespace {
wait_queue_head_t poll;
struct rcu_head mnt_ns_rcu;
};
+ u64 seq_origin; /* Sequence number of origin mount namespace */
u64 event;
unsigned int nr_mounts; /* # of mounts in the namespace */
unsigned int pending_mounts;
diff --git a/fs/namespace.c b/fs/namespace.c
index a3ed3f2980cb..9bcfb405b02b 100644
--- a/fs/namespace.c
+++ b/fs/namespace.c
@@ -2853,15 +2853,28 @@ 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, *mnt_ns = current->nsproxy->mnt_ns, *src_mnt_ns;
+ struct user_namespace *user_ns = mnt_ns->user_ns;
struct mount *mnt, *p;
struct file *file;
+ ns = alloc_mnt_ns(user_ns, true);
if (IS_ERR(ns))
return ERR_CAST(ns);
namespace_lock();
+
+ /*
+ * Record the sequence number of the source mount namespace.
+ * This needs to hold namespace_sem to ensure that the mount
+ * doesn't get attached.
+ */
+ src_mnt_ns = real_mount(path->mnt)->mnt_ns;
+ if (is_anon_ns(src_mnt_ns))
+ ns->seq_origin = src_mnt_ns->seq_origin;
+ else
+ ns->seq_origin = src_mnt_ns->seq;
+
mnt = __do_loopback(path, recursive);
if (IS_ERR(mnt)) {
namespace_unlock();
--
2.47.2
