checks if mount is the root of an anonymouns namespace.
Switch open-coded equivalents to using it.
For mounts that belong to anon namespace !mnt_has_parent(mount)
is the same as mount == ns->root, and intent is more obvious in
the latter form.
Reviewed-by: Christian Brauner <brauner@xxxxxxxxxx>
Signed-off-by: Al Viro <viro@xxxxxxxxxxxxxxxxxx>
---
fs/mount.h | 7 +++++++
fs/namespace.c | 28 +++-------------------------
2 files changed, 10 insertions(+), 25 deletions(-)
diff --git a/fs/mount.h b/fs/mount.h
index f10776003643..f20e6ed845fe 100644
--- a/fs/mount.h
+++ b/fs/mount.h
@@ -161,6 +161,13 @@ static inline bool is_anon_ns(struct mnt_namespace *ns)
return ns->seq == 0;
}
+static inline bool anon_ns_root(const struct mount *m)
+{
+ struct mnt_namespace *ns = READ_ONCE(m->mnt_ns);
+
+ return !IS_ERR_OR_NULL(ns) && is_anon_ns(ns) && m == ns->root;
+}
+
static inline bool mnt_ns_attached(const struct mount *mnt)
{
return !RB_EMPTY_NODE(&mnt->mnt_node);
diff --git a/fs/namespace.c b/fs/namespace.c
index c4feb8315978..ea01fea2ac93 100644
--- a/fs/namespace.c
+++ b/fs/namespace.c
@@ -2480,9 +2480,7 @@ struct vfsmount *clone_private_mount(const struct path *path)
* loops get created.
*/
if (!check_mnt(old_mnt)) {
- if (!is_mounted(&old_mnt->mnt) ||
- !is_anon_ns(old_mnt->mnt_ns) ||
- mnt_has_parent(old_mnt))
+ if (!anon_ns_root(old_mnt))
return ERR_PTR(-EINVAL);
if (!check_for_nsfs_mounts(old_mnt))
@@ -3649,9 +3647,6 @@ static int do_move_mount(struct path *old_path,
ns = old->mnt_ns;
err = -EINVAL;
- /* The thing moved must be mounted... */
- if (!is_mounted(&old->mnt))
- goto out;
if (check_mnt(old)) {
/* if the source is in our namespace... */
@@ -3664,10 +3659,8 @@ static int do_move_mount(struct path *old_path,
} else {
/*
* otherwise the source must be the root of some anon namespace.
- * AV: check for mount being root of an anon namespace is worth
- * an inlined predicate...
*/
- if (!is_anon_ns(ns) || mnt_has_parent(old))
+ if (!anon_ns_root(old))
goto out;
/*
* Bail out early if the target is within the same namespace -
@@ -5028,22 +5021,7 @@ static int do_mount_setattr(struct path *path, struct mount_kattr *kattr)
err = -EINVAL;
lock_mount_hash();
- /* Ensure that this isn't anything purely vfs internal. */
- if (!is_mounted(&mnt->mnt))
- goto out;
-
- /*
- * If this is an attached mount make sure it's located in the callers
- * mount namespace. If it's not don't let the caller interact with it.
- *
- * If this mount doesn't have a parent it's most often simply a
- * detached mount with an anonymous mount namespace. IOW, something
- * that's simply not attached yet. But there are apparently also users
- * that do change mount properties on the rootfs itself. That obviously
- * neither has a parent nor is it a detached mount so we cannot
- * unconditionally check for detached mounts.
- */
- if ((mnt_has_parent(mnt) || !is_anon_ns(mnt->mnt_ns)) && !check_mnt(mnt))
+ if (!anon_ns_root(mnt) && !check_mnt(mnt))
goto out;
/*
--
2.39.5
