return m;
}
+static inline void lock_ns_list(struct mnt_namespace *ns)
+{
+ spin_lock(&ns->ns_lock);
+}
+
+static inline void unlock_ns_list(struct mnt_namespace *ns)
+{
+ spin_unlock(&ns->ns_lock);
+}
+
+static inline bool mnt_is_cursor(struct mount *mnt)
+{
+ return mnt->mnt.mnt_flags & MNT_CURSOR;
+}
+
/*
* __is_local_mountpoint - Test to see if dentry is a mountpoint in the
* current mount namespace.
struct mount *mnt;
bool is_covered = false;
- if (!d_mountpoint(dentry))
- goto out;
-
down_read(&namespace_sem);
+ lock_ns_list(ns);
list_for_each_entry(mnt, &ns->list, mnt_list) {
+ if (mnt_is_cursor(mnt))
+ continue;
is_covered = (mnt->mnt_mountpoint == dentry);
if (is_covered)
break;
}
+ unlock_ns_list(ns);
up_read(&namespace_sem);
-out:
+
return is_covered;
}
}
#ifdef CONFIG_PROC_FS
+static struct mount *mnt_list_next(struct mnt_namespace *ns,
+ struct list_head *p)
+{
+ struct mount *mnt, *ret = NULL;
+
+ lock_ns_list(ns);
+ list_for_each_continue(p, &ns->list) {
+ mnt = list_entry(p, typeof(*mnt), mnt_list);
+ if (!mnt_is_cursor(mnt)) {
+ ret = mnt;
+ break;
+ }
+ }
+ unlock_ns_list(ns);
+
+ return ret;
+}
+
/* iterator; we want it to have access to namespace_sem, thus here... */
static void *m_start(struct seq_file *m, loff_t *pos)
{
struct proc_mounts *p = m->private;
+ struct list_head *prev;
down_read(&namespace_sem);
- if (p->cached_event == p->ns->event) {
- void *v = p->cached_mount;
- if (*pos == p->cached_index)
- return v;
- if (*pos == p->cached_index + 1) {
- v = seq_list_next(v, &p->ns->list, &p->cached_index);
- return p->cached_mount = v;
- }
+ if (!*pos) {
+ prev = &p->ns->list;
+ } else {
+ prev = &p->cursor.mnt_list;
+
+ /* Read after we'd reached the end? */
+ if (list_empty(prev))
+ return NULL;
}
- p->cached_event = p->ns->event;
- p->cached_mount = seq_list_start(&p->ns->list, *pos);
- p->cached_index = *pos;
- return p->cached_mount;
+ return mnt_list_next(p->ns, prev);
}
static void *m_next(struct seq_file *m, void *v, loff_t *pos)
{
struct proc_mounts *p = m->private;
+ struct mount *mnt = v;
- p->cached_mount = seq_list_next(v, &p->ns->list, pos);
- p->cached_index = *pos;
- return p->cached_mount;
+ ++*pos;
+ return mnt_list_next(p->ns, &mnt->mnt_list);
}
static void m_stop(struct seq_file *m, void *v)
{
+ struct proc_mounts *p = m->private;
+ struct mount *mnt = v;
+
+ lock_ns_list(p->ns);
+ if (mnt)
+ list_move_tail(&p->cursor.mnt_list, &mnt->mnt_list);
+ else
+ list_del_init(&p->cursor.mnt_list);
+ unlock_ns_list(p->ns);
up_read(&namespace_sem);
}
static int m_show(struct seq_file *m, void *v)
{
struct proc_mounts *p = m->private;
- struct mount *r = list_entry(v, struct mount, mnt_list);
+ struct mount *r = v;
return p->show(m, &r->mnt);
}
.stop = m_stop,
.show = m_show,
};
+
+void mnt_cursor_del(struct mnt_namespace *ns, struct mount *cursor)
+{
+ down_read(&namespace_sem);
+ lock_ns_list(ns);
+ list_del(&cursor->mnt_list);
+ unlock_ns_list(ns);
+ up_read(&namespace_sem);
+}
#endif /* CONFIG_PROC_FS */
/**
struct path path;
struct mount *mnt;
int retval;
- int lookup_flags = 0;
+ int lookup_flags = LOOKUP_MOUNTPOINT;
if (flags & ~(MNT_FORCE | MNT_DETACH | MNT_EXPIRE | UMOUNT_NOFOLLOW))
return -EINVAL;
if (!(flags & UMOUNT_NOFOLLOW))
lookup_flags |= LOOKUP_FOLLOW;
- retval = user_path_mountpoint_at(AT_FDCWD, name, lookup_flags, &path);
+ retval = user_path_at(AT_FDCWD, name, lookup_flags, &path);
if (retval)
goto out;
mnt = real_mount(path.mnt);
return container_of(ns, struct mnt_namespace, ns);
}
+struct ns_common *from_mnt_ns(struct mnt_namespace *mnt)
+{
+ return &mnt->ns;
+}
+
static bool mnt_ns_loop(struct dentry *dentry)
{
/* Could bind mounting the mount namespace inode cause a
if (IS_ERR(new_mnt))
return ERR_CAST(new_mnt);
+ /* Longterm mount to be removed by kern_unmount*() */
+ new_mnt->mnt_ns = MNT_NS_INTERNAL;
+
return &new_mnt->mnt;
}
EXPORT_SYMBOL_GPL(clone_private_mount);
/*
* add a mount into a namespace's mount tree
*/
-static int do_add_mount(struct mount *newmnt, struct path *path, int mnt_flags)
+static int do_add_mount(struct mount *newmnt, struct mountpoint *mp,
+ struct path *path, int mnt_flags)
{
- struct mountpoint *mp;
- struct mount *parent;
- int err;
+ struct mount *parent = real_mount(path->mnt);
mnt_flags &= ~MNT_INTERNAL_FLAGS;
- mp = lock_mount(path);
- if (IS_ERR(mp))
- return PTR_ERR(mp);
-
- parent = real_mount(path->mnt);
- err = -EINVAL;
if (unlikely(!check_mnt(parent))) {
/* that's acceptable only for automounts done in private ns */
if (!(mnt_flags & MNT_SHRINKABLE))
- goto unlock;
+ return -EINVAL;
/* ... and for those we'd better have mountpoint still alive */
if (!parent->mnt_ns)
- goto unlock;
+ return -EINVAL;
}
/* Refuse the same filesystem on the same mount point */
- err = -EBUSY;
if (path->mnt->mnt_sb == newmnt->mnt.mnt_sb &&
path->mnt->mnt_root == path->dentry)
- goto unlock;
+ return -EBUSY;
- err = -EINVAL;
if (d_is_symlink(newmnt->mnt.mnt_root))
- goto unlock;
+ return -EINVAL;
newmnt->mnt.mnt_flags = mnt_flags;
- err = graft_tree(newmnt, parent, mp);
-
-unlock:
- unlock_mount(mp);
- return err;
+ return graft_tree(newmnt, parent, mp);
}
static bool mount_too_revealing(const struct super_block *sb, int *new_mnt_flags);
unsigned int mnt_flags)
{
struct vfsmount *mnt;
+ struct mountpoint *mp;
struct super_block *sb = fc->root->d_sb;
int error;
mnt_warn_timestamp_expiry(mountpoint, mnt);
- error = do_add_mount(real_mount(mnt), mountpoint, mnt_flags);
+ mp = lock_mount(mountpoint);
+ if (IS_ERR(mp)) {
+ mntput(mnt);
+ return PTR_ERR(mp);
+ }
+ error = do_add_mount(real_mount(mnt), mp, mountpoint, mnt_flags);
+ unlock_mount(mp);
if (error < 0)
mntput(mnt);
return error;
int finish_automount(struct vfsmount *m, struct path *path)
{
- struct mount *mnt = real_mount(m);
+ struct dentry *dentry = path->dentry;
+ struct mountpoint *mp;
+ struct mount *mnt;
int err;
+
+ if (!m)
+ return 0;
+ if (IS_ERR(m))
+ return PTR_ERR(m);
+
+ mnt = real_mount(m);
/* The new mount record should have at least 2 refs to prevent it being
* expired before we get a chance to add it
*/
BUG_ON(mnt_get_count(mnt) < 2);
if (m->mnt_sb == path->mnt->mnt_sb &&
- m->mnt_root == path->dentry) {
+ m->mnt_root == dentry) {
err = -ELOOP;
- goto fail;
+ goto discard;
}
- err = do_add_mount(mnt, path, path->mnt->mnt_flags | MNT_SHRINKABLE);
- if (!err)
- return 0;
-fail:
+ /*
+ * we don't want to use lock_mount() - in this case finding something
+ * that overmounts our mountpoint to be means "quitely drop what we've
+ * got", not "try to mount it on top".
+ */
+ inode_lock(dentry->d_inode);
+ namespace_lock();
+ if (unlikely(cant_mount(dentry))) {
+ err = -ENOENT;
+ goto discard_locked;
+ }
+ rcu_read_lock();
+ if (unlikely(__lookup_mnt(path->mnt, dentry))) {
+ rcu_read_unlock();
+ err = 0;
+ goto discard_locked;
+ }
+ rcu_read_unlock();
+ mp = get_mountpoint(dentry);
+ if (IS_ERR(mp)) {
+ err = PTR_ERR(mp);
+ goto discard_locked;
+ }
+
+ err = do_add_mount(mnt, mp, path, path->mnt->mnt_flags | MNT_SHRINKABLE);
+ unlock_mount(mp);
+ if (unlikely(err))
+ goto discard;
+ mntput(m);
+ return 0;
+
+discard_locked:
+ namespace_unlock();
+ inode_unlock(dentry->d_inode);
+discard:
/* remove m from any expiration list it may be on */
if (!list_empty(&mnt->mnt_expire)) {
namespace_lock();
atomic_set(&new_ns->count, 1);
INIT_LIST_HEAD(&new_ns->list);
init_waitqueue_head(&new_ns->poll);
+ spin_lock_init(&new_ns->ns_lock);
new_ns->user_ns = get_user_ns(user_ns);
new_ns->ucounts = ucounts;
return new_ns;
* file system may be mounted on put_old. After all, new_root is a mountpoint.
*
* Also, the current root cannot be on the 'rootfs' (initial ramfs) filesystem.
- * See Documentation/filesystems/ramfs-rootfs-initramfs.txt for alternatives
+ * See Documentation/filesystems/ramfs-rootfs-initramfs.rst for alternatives
* in this situation.
*
* Notes:
}
EXPORT_SYMBOL(kern_unmount);
+void kern_unmount_array(struct vfsmount *mnt[], unsigned int num)
+{
+ unsigned int i;
+
+ for (i = 0; i < num; i++)
+ if (mnt[i])
+ real_mount(mnt[i])->mnt_ns = NULL;
+ synchronize_rcu_expedited();
+ for (i = 0; i < num; i++)
+ mntput(mnt[i]);
+}
+EXPORT_SYMBOL(kern_unmount_array);
+
bool our_mnt(struct vfsmount *mnt)
{
return check_mnt(real_mount(mnt));
bool visible = false;
down_read(&namespace_sem);
+ lock_ns_list(ns);
list_for_each_entry(mnt, &ns->list, mnt_list) {
struct mount *child;
int mnt_flags;
+ if (mnt_is_cursor(mnt))
+ continue;
+
if (mnt->mnt.mnt_sb->s_type != sb->s_type)
continue;
next: ;
}
found:
+ unlock_ns_list(ns);
up_read(&namespace_sem);
return visible;
}
put_mnt_ns(to_mnt_ns(ns));
}
-static int mntns_install(struct nsproxy *nsproxy, struct ns_common *ns)
+static int mntns_install(struct nsset *nsset, struct ns_common *ns)
{
- struct fs_struct *fs = current->fs;
+ struct nsproxy *nsproxy = nsset->nsproxy;
+ struct fs_struct *fs = nsset->fs;
struct mnt_namespace *mnt_ns = to_mnt_ns(ns), *old_mnt_ns;
+ struct user_namespace *user_ns = nsset->cred->user_ns;
struct path root;
int err;
if (!ns_capable(mnt_ns->user_ns, CAP_SYS_ADMIN) ||
- !ns_capable(current_user_ns(), CAP_SYS_CHROOT) ||
- !ns_capable(current_user_ns(), CAP_SYS_ADMIN))
+ !ns_capable(user_ns, CAP_SYS_CHROOT) ||
+ !ns_capable(user_ns, CAP_SYS_ADMIN))
return -EPERM;
if (is_anon_ns(mnt_ns))
projects / linux-2.6-microblaze.git / blobdiff