In order to utilize the listmount() and statmount() extensions that
allow us to call them on different namespaces we need a way to get the
mnt namespace id from user space. Add an ioctl to nsfs that will allow
us to extract the mnt namespace id in order to make these new extensions
usable.
Signed-off-by: Josef Bacik <josef@xxxxxxxxxxxxxx>
---
fs/nsfs.c | 14 ++++++++++++++
include/uapi/linux/nsfs.h | 2 ++
2 files changed, 16 insertions(+)
diff --git a/fs/nsfs.c b/fs/nsfs.c
index 07e22a15ef02..af352dadffe1 100644
--- a/fs/nsfs.c
+++ b/fs/nsfs.c
@@ -12,6 +12,7 @@
#include <linux/nsfs.h>
#include <linux/uaccess.h>
+#include "mount.h"
#include "internal.h"
static struct vfsmount *nsfs_mnt;
@@ -143,6 +144,19 @@ static long ns_ioctl(struct file *filp, unsigned int ioctl,
argp = (uid_t __user *) arg;
uid = from_kuid_munged(current_user_ns(), user_ns->owner);
return put_user(uid, argp);
+ case NS_GET_MNTNS_ID: {
+ struct mnt_namespace *mnt_ns;
+ __u64 __user *idp;
+ __u64 id;
+
+ if (ns->ops->type != CLONE_NEWNS)
+ return -EINVAL;
+
+ mnt_ns = container_of(ns, struct mnt_namespace, ns);
+ idp = (__u64 __user *)arg;
+ id = mnt_ns->seq;
+ return put_user(id, idp);
+ }
default:
return -ENOTTY;
}
diff --git a/include/uapi/linux/nsfs.h b/include/uapi/linux/nsfs.h
index a0c8552b64ee..56e8b1639b98 100644
--- a/include/uapi/linux/nsfs.h
+++ b/include/uapi/linux/nsfs.h
@@ -15,5 +15,7 @@
#define NS_GET_NSTYPE _IO(NSIO, 0x3)
/* Get owner UID (in the caller's user namespace) for a user namespace */
#define NS_GET_OWNER_UID _IO(NSIO, 0x4)
+/* Get the id for a mount namespace */
+#define NS_GET_MNTNS_ID _IO(NSIO, 0x5)
#endif /* __LINUX_NSFS_H */
--
2.43.0
