diff options
Diffstat (limited to 'fs/namespace.c')
| -rw-r--r-- | fs/namespace.c | 30 |
1 files changed, 30 insertions, 0 deletions
diff --git a/fs/namespace.c b/fs/namespace.c index e5e1c7d1839..50ee30345b4 100644 --- a/fs/namespace.c +++ b/fs/namespace.c @@ -2483,11 +2483,41 @@ struct mnt_namespace *create_mnt_ns(struct vfsmount *mnt) __mnt_make_longterm(mnt); new_ns->root = mnt; list_add(&new_ns->list, &new_ns->root->mnt_list); + } else { + mntput(mnt); } return new_ns; } EXPORT_SYMBOL(create_mnt_ns); +struct dentry *mount_subtree(struct vfsmount *mnt, const char *name) +{ + struct mnt_namespace *ns; + struct path path; + int err; + + ns = create_mnt_ns(mnt); + if (IS_ERR(ns)) + return ERR_CAST(ns); + + err = vfs_path_lookup(mnt->mnt_root, mnt, + name, LOOKUP_FOLLOW|LOOKUP_AUTOMOUNT, &path); + + put_mnt_ns(ns); + + if (err) + return ERR_PTR(err); + + /* trade a vfsmount reference for active sb one */ + atomic_inc(&path.mnt->mnt_sb->s_active); + mntput(path.mnt); + /* lock the sucker */ + down_write(&path.mnt->mnt_sb->s_umount); + /* ... and return the root of (sub)tree on it */ + return path.dentry; +} +EXPORT_SYMBOL(mount_subtree); + SYSCALL_DEFINE5(mount, char __user *, dev_name, char __user *, dir_name, char __user *, type, unsigned long, flags, void __user *, data) { |