diff options
| -rw-r--r-- | fs/namespace.c | 11 | ||||
| -rw-r--r-- | fs/pnode.c | 198 | ||||
| -rw-r--r-- | fs/pnode.h | 3 | ||||
| -rw-r--r-- | include/linux/mount.h | 3 |
4 files changed, 133 insertions, 82 deletions
diff --git a/fs/namespace.c b/fs/namespace.c index 2ffc5a2..65233a5 100644 --- a/fs/namespace.c +++ b/fs/namespace.c @@ -885,7 +885,7 @@ static struct mount *clone_mnt(struct mount *old, struct dentry *root, goto out_free; } - mnt->mnt.mnt_flags = old->mnt.mnt_flags & ~MNT_WRITE_HOLD; + mnt->mnt.mnt_flags = old->mnt.mnt_flags & ~(MNT_WRITE_HOLD|MNT_MARKED); /* Don't allow unprivileged users to change mount flags */ if ((flag & CL_UNPRIVILEGED) && (mnt->mnt.mnt_flags & MNT_READONLY)) mnt->mnt.mnt_flags |= MNT_LOCK_READONLY; @@ -1661,9 +1661,9 @@ static int attach_recursive_mnt(struct mount *source_mnt, if (err) goto out; err = propagate_mnt(dest_mnt, dest_mp, source_mnt, &tree_list); + lock_mount_hash(); if (err) goto out_cleanup_ids; - lock_mount_hash(); for (p = source_mnt; p; p = next_mnt(p, source_mnt)) set_mnt_shared(p); } else { @@ -1690,6 +1690,11 @@ static int attach_recursive_mnt(struct mount *source_mnt, return 0; out_cleanup_ids: + while (!hlist_empty(&tree_list)) { + child = hlist_entry(tree_list.first, struct mount, mnt_hash); + umount_tree(child, 0); + } + unlock_mount_hash(); cleanup_group_ids(source_mnt, NULL); out: return err; @@ -2044,7 +2049,7 @@ static int do_add_mount(struct mount *newmnt, struct path *path, int mnt_flags) struct mount *parent; int err; - mnt_flags &= ~(MNT_SHARED | MNT_WRITE_HOLD | MNT_INTERNAL | MNT_DOOMED | MNT_SYNC_UMOUNT); + mnt_flags &= ~MNT_INTERNAL_FLAGS; mp = lock_mount(path); if (IS_ERR(mp)) @@ -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; } @@ -16,6 +16,9 @@ #define IS_MNT_NEW(m) (!(m)->mnt_ns) #define CLEAR_MNT_SHARED(m) ((m)->mnt.mnt_flags &= ~MNT_SHARED) #define IS_MNT_UNBINDABLE(m) ((m)->mnt.mnt_flags & MNT_UNBINDABLE) +#define IS_MNT_MARKED(m) ((m)->mnt.mnt_flags & MNT_MARKED) +#define SET_MNT_MARK(m) ((m)->mnt.mnt_flags |= MNT_MARKED) +#define CLEAR_MNT_MARK(m) ((m)->mnt.mnt_flags &= ~MNT_MARKED) #define CL_EXPIRE 0x01 #define CL_SLAVE 0x02 diff --git a/include/linux/mount.h b/include/linux/mount.h index 371d346..839bac2 100644 --- a/include/linux/mount.h +++ b/include/linux/mount.h @@ -44,6 +44,8 @@ struct mnt_namespace; #define MNT_SHARED_MASK (MNT_UNBINDABLE) #define MNT_PROPAGATION_MASK (MNT_SHARED | MNT_UNBINDABLE) +#define MNT_INTERNAL_FLAGS (MNT_SHARED | MNT_WRITE_HOLD | MNT_INTERNAL | \ + MNT_DOOMED | MNT_SYNC_UMOUNT | MNT_MARKED) #define MNT_INTERNAL 0x4000 @@ -51,6 +53,7 @@ struct mnt_namespace; #define MNT_LOCKED 0x800000 #define MNT_DOOMED 0x1000000 #define MNT_SYNC_UMOUNT 0x2000000 +#define MNT_MARKED 0x4000000 struct vfsmount { struct dentry *mnt_root; /* root of the mounted tree */ |
