diff options
Diffstat (limited to 'fs/namespace.c')
| -rw-r--r-- | fs/namespace.c | 35 |
1 files changed, 35 insertions, 0 deletions
diff --git a/fs/namespace.c b/fs/namespace.c index 044134315f93..77ffdb82f63f 100644 --- a/fs/namespace.c +++ b/fs/namespace.c @@ -667,6 +667,41 @@ struct vfsmount *lookup_mnt(struct path *path) return m; } +/* + * __is_local_mountpoint - Test to see if dentry is a mountpoint in the + * current mount namespace. + * + * The common case is dentries are not mountpoints at all and that + * test is handled inline. For the slow case when we are actually + * dealing with a mountpoint of some kind, walk through all of the + * mounts in the current mount namespace and test to see if the dentry + * is a mountpoint. + * + * The mount_hashtable is not usable in the context because we + * need to identify all mounts that may be in the current mount + * namespace not just a mount that happens to have some specified + * parent mount. + */ +bool __is_local_mountpoint(struct dentry *dentry) +{ + struct mnt_namespace *ns = current->nsproxy->mnt_ns; + struct mount *mnt; + bool is_covered = false; + + if (!d_mountpoint(dentry)) + goto out; + + down_read(&namespace_sem); + list_for_each_entry(mnt, &ns->list, mnt_list) { + is_covered = (mnt->mnt_mountpoint == dentry); + if (is_covered) + break; + } + up_read(&namespace_sem); +out: + return is_covered; +} + static struct mountpoint *new_mountpoint(struct dentry *dentry) { struct hlist_head *chain = mp_hash(dentry); |