diff options
Diffstat (limited to 'fs/pnode.c')
| -rw-r--r-- | fs/pnode.c | 198 |
1 files changed, 119 insertions, 79 deletions
@@ -164,46 +164,94 @@ static struct mount *propagation_next(struct mount *m, } } -/* - * return the source mount to be used for cloning - * - * @dest the current destination mount - * @last_dest the last seen destination mount - * @last_src the last seen source mount - * @type return CL_SLAVE if the new mount has to be - * cloned as a slave. - */ -static struct mount *get_source(struct mount *dest, - struct mount *last_dest, - struct mount *last_src, - int *type) +static struct mount *next_group(struct mount *m, struct mount *origin) { - struct mount *p_last_src = NULL; - struct mount *p_last_dest = NULL; - - while (last_dest != dest->mnt_master) { - p_last_dest = last_dest; - p_last_src = last_src; - last_dest = last_dest->mnt_master; - last_src = last_src->mnt_master; + while (1) { + while (1) { + struct mount *next; + if (!IS_MNT_NEW(m) && !list_empty(&m->mnt_slave_list)) + return first_slave(m); + next = next_peer(m); + if (m->mnt_group_id == origin->mnt_group_id) { + if (next == origin) + return NULL; + } else if (m->mnt_slave.next != &next->mnt_slave) + break; + m = next; + } + /* m is the last peer */ + while (1) { + struct mount *master = m->mnt_master; + if (m->mnt_slave.next != &master->mnt_slave_list) + return next_slave(m); + m = next_peer(master); + if (master->mnt_group_id == origin->mnt_group_id) + break; + if (master->mnt_slave.next == &m->mnt_slave) + break; + m = master; + } + if (m == origin) + return NULL; } +} - if (p_last_dest) { - do { - p_last_dest = next_peer(p_last_dest); - } while (IS_MNT_NEW(p_last_dest)); - /* is that a peer of the earlier? */ - if (dest == p_last_dest) { - *type = CL_MAKE_SHARED; - return p_last_src; +/* all accesses are serialized by namespace_sem */ +static struct user_namespace *user_ns; +static struct mount *last_dest, *last_source, *dest_master; +static struct mountpoint *mp; +static struct hlist_head *list; + +static int propagate_one(struct mount *m) +{ + struct mount *child; + int type; + /* skip ones added by this propagate_mnt() */ + if (IS_MNT_NEW(m)) + return 0; + /* skip if mountpoint isn't covered by it */ + if (!is_subdir(mp->m_dentry, m->mnt.mnt_root)) + return 0; + if (m->mnt_group_id == last_dest->mnt_group_id) { + type = CL_MAKE_SHARED; + } else { + struct mount *n, *p; + for (n = m; ; n = p) { + p = n->mnt_master; + if (p == dest_master || IS_MNT_MARKED(p)) { + while (last_dest->mnt_master != p) { + last_source = last_source->mnt_master; + last_dest = last_source->mnt_parent; + } + if (n->mnt_group_id != last_dest->mnt_group_id) { + last_source = last_source->mnt_master; + last_dest = last_source->mnt_parent; + } + break; + } } + type = CL_SLAVE; + /* beginning of peer group among the slaves? */ + if (IS_MNT_SHARED(m)) + type |= CL_MAKE_SHARED; } - /* slave of the earlier, then */ - *type = CL_SLAVE; - /* beginning of peer group among the slaves? */ - if (IS_MNT_SHARED(dest)) - *type |= CL_MAKE_SHARED; - return last_src; + + /* Notice when we are propagating across user namespaces */ + if (m->mnt_ns->user_ns != user_ns) + type |= CL_UNPRIVILEGED; + child = copy_tree(last_source, last_source->mnt.mnt_root, type); + if (IS_ERR(child)) + return PTR_ERR(child); + mnt_set_mountpoint(m, mp, child); + last_dest = m; + last_source = child; + if (m->mnt_master != dest_master) { + read_seqlock_excl(&mount_lock); + SET_MNT_MARK(m->mnt_master); + read_sequnlock_excl(&mount_lock); + } + hlist_add_head(&child->mnt_hash, list); + return 0; } /* @@ -222,56 +270,48 @@ static struct mount *get_source(struct mount *dest, int propagate_mnt(struct mount *dest_mnt, struct mountpoint *dest_mp, struct mount *source_mnt, struct hlist_head *tree_list) { - struct user_namespace *user_ns = current->nsproxy->mnt_ns->user_ns; - struct mount *m, *child; + struct mount *m, *n; int ret = 0; - struct mount *prev_dest_mnt = dest_mnt; - struct mount *prev_src_mnt = source_mnt; - HLIST_HEAD(tmp_list); - - for (m = propagation_next(dest_mnt, dest_mnt); m; - m = propagation_next(m, dest_mnt)) { - int type; - struct mount *source; - - if (IS_MNT_NEW(m)) - continue; - - source = get_source(m, prev_dest_mnt, prev_src_mnt, &type); - - /* Notice when we are propagating across user namespaces */ - if (m->mnt_ns->user_ns != user_ns) - type |= CL_UNPRIVILEGED; - - child = copy_tree(source, source->mnt.mnt_root, type); - if (IS_ERR(child)) { - ret = PTR_ERR(child); - tmp_list = *tree_list; - tmp_list.first->pprev = &tmp_list.first; - INIT_HLIST_HEAD(tree_list); + + /* + * we don't want to bother passing tons of arguments to + * propagate_one(); everything is serialized by namespace_sem, + * so globals will do just fine. + */ + user_ns = current->nsproxy->mnt_ns->user_ns; + last_dest = dest_mnt; + last_source = source_mnt; + mp = dest_mp; + list = tree_list; + dest_master = dest_mnt->mnt_master; + + /* all peers of dest_mnt, except dest_mnt itself */ + for (n = next_peer(dest_mnt); n != dest_mnt; n = next_peer(n)) { + ret = propagate_one(n); + if (ret) goto out; - } + } - if (is_subdir(dest_mp->m_dentry, m->mnt.mnt_root)) { - mnt_set_mountpoint(m, dest_mp, child); - hlist_add_head(&child->mnt_hash, tree_list); - } else { - /* - * This can happen if the parent mount was bind mounted - * on some subdirectory of a shared/slave mount. - */ - hlist_add_head(&child->mnt_hash, &tmp_list); - } - prev_dest_mnt = m; - prev_src_mnt = child; + /* all slave groups */ + for (m = next_group(dest_mnt, dest_mnt); m; + m = next_group(m, dest_mnt)) { + /* everything in that slave group */ + n = m; + do { + ret = propagate_one(n); + if (ret) + goto out; + n = next_peer(n); + } while (n != m); } out: - lock_mount_hash(); - while (!hlist_empty(&tmp_list)) { - child = hlist_entry(tmp_list.first, struct mount, mnt_hash); - umount_tree(child, 0); + read_seqlock_excl(&mount_lock); + hlist_for_each_entry(n, tree_list, mnt_hash) { + m = n->mnt_parent; + if (m->mnt_master != dest_mnt->mnt_master) + CLEAR_MNT_MARK(m->mnt_master); } - unlock_mount_hash(); + read_sequnlock_excl(&mount_lock); return ret; } |
