diff options
| author | Christian Brauner <brauner@kernel.org> | 2025-02-21 14:13:00 +0100 |
|---|---|---|
| committer | Christian Brauner <brauner@kernel.org> | 2025-03-04 09:29:19 +0100 |
| commit | 3b0cdba4da55188b8ae49430f2730fade56b43ae (patch) | |
| tree | c3437c79475f073d4d166c83398a4d99632bf763 | |
| parent | 822c11592522dc00e1f447dbe95350071001d9f1 (diff) | |
fs: record sequence number of origin mount namespace
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.
Link: https://lore.kernel.org/r/20250221-brauner-open_tree-v1-1-dbcfcb98c676@kernel.org
Signed-off-by: Christian Brauner <brauner@kernel.org>
| -rw-r--r-- | fs/mount.h | 1 | ||||
| -rw-r--r-- | fs/namespace.c | 19 |
2 files changed, 18 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..d5c85b6ecb98 100644 --- a/fs/namespace.c +++ b/fs/namespace.c @@ -2853,15 +2853,30 @@ out: 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. + */ + if (is_mounted(path->mnt)) { + 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(); |