diff -urN FS-slave_operations/fs/namespace.c FS-unbindable_mount/fs/namespace.c --- FS-slave_operations/fs/namespace.c 2005-11-03 07:23:43.000000000 -0500 +++ FS-unbindable_mount/fs/namespace.c 2005-11-03 07:24:11.000000000 -0500 @@ -213,6 +213,16 @@ return list_entry(next, struct vfsmount, mnt_child); } +static struct vfsmount *skip_mnt_tree(struct vfsmount *p) +{ + struct list_head *prev = p->mnt_mounts.prev; + while (prev != &p->mnt_mounts) { + p = list_entry(prev, struct vfsmount, mnt_child); + prev = p->mnt_mounts.prev; + } + return p; +} + static struct vfsmount *clone_mnt(struct vfsmount *old, struct dentry *root, int flag) { @@ -650,6 +660,9 @@ struct vfsmount *res, *p, *q, *r, *s; struct nameidata nd; + if (!(flag & CL_COPY_ALL) && IS_MNT_UNBINDABLE(mnt)) + return NULL; + res = q = clone_mnt(mnt, dentry, flag); if (!q) goto Enomem; @@ -661,6 +674,10 @@ continue; for (s = r; s; s = next_mnt(s, r)) { + if (!(flag & CL_COPY_ALL) && IS_MNT_UNBINDABLE(s)) { + s = skip_mnt_tree(s); + continue; + } while (p != s->mnt_parent) { p = p->mnt_parent; q = q->mnt_parent; @@ -698,18 +715,18 @@ * * NOTE: in the table below explains the semantics when a source mount * of a given type is attached to a destination mount of a given type. - * ------------------------------------------------------------- - * | BIND MOUNT OPERATION | - * |************************************************************* - * | source-->| shared | private | slave | - * | dest | | | | - * | | | | | | - * | v | | | | - * |************************************************************* - * | shared | shared (++) | shared (+) | shared(+++)| - * | | | | | - * |non-shared| shared (+) | private | slave (*) | - * ************************************************************** + * --------------------------------------------------------------------------- + * | BIND MOUNT OPERATION | + * |************************************************************************** + * | source-->| shared | private | slave | unbindable | + * | dest | | | | | + * | | | | | | | + * | v | | | | | + * |************************************************************************** + * | shared | shared (++) | shared (+) | shared(+++)| invalid | + * | | | | | | + * |non-shared| shared (+) | private | slave (*) | invalid | + * *************************************************************************** * A bind operation clones the source mount and mounts the clone on the * destination mount. * @@ -726,18 +743,18 @@ * (*) the cloned mount is made a slave of the same master as that of the * source mount. * - * -------------------------------------------------------------- - * | MOVE MOUNT OPERATION | - * |************************************************************* - * | source-->| shared | private | slave | - * | dest | | | | - * | | | | | | - * | v | | | | - * |************************************************************* - * | shared | shared (+) | shared (+) | shared(+++) | - * | | | | | - * |non-shared| shared (+*) | private | slave (*) | - * ************************************************************** + * --------------------------------------------------------------------------- + * | MOVE MOUNT OPERATION | + * |************************************************************************** + * | source-->| shared | private | slave | unbindable | + * | dest | | | | | + * | | | | | | | + * | v | | | | | + * |************************************************************************** + * | shared | shared (+) | shared (+) | shared(+++) | invalid | + * | | | | | | + * |non-shared| shared (+*) | private | slave (*) | unbindable | + * *************************************************************************** * * (+) the mount is moved to the destination. And is then propagated to * all the mounts in the propagation tree of the destination mount. @@ -854,6 +871,9 @@ down_write(&namespace_sem); err = -EINVAL; + if (IS_MNT_UNBINDABLE(old_nd.mnt)) + goto out; + if (!check_mnt(nd->mnt) || !check_mnt(old_nd.mnt)) goto out; @@ -911,6 +931,16 @@ return err; } +static inline int tree_contains_unbindable(struct vfsmount *mnt) +{ + struct vfsmount *p; + for (p = mnt; p; p = next_mnt(p, mnt)) { + if (IS_MNT_UNBINDABLE(p)) + return 1; + } + return 0; +} + static int do_move_mount(struct nameidata *nd, char *old_name) { struct nameidata old_nd, parent_nd; @@ -954,6 +984,12 @@ */ if (old_nd.mnt->mnt_parent && IS_MNT_SHARED(old_nd.mnt->mnt_parent)) goto out1; + /* + * Don't move a mount tree containing unbindable mounts to a destination + * mount which is shared. + */ + if (IS_MNT_SHARED(nd->mnt) && tree_contains_unbindable(old_nd.mnt)) + goto out1; err = -ELOOP; for (p = nd->mnt; p->mnt_parent != p; p = p->mnt_parent) if (p == old_nd.mnt) @@ -1266,7 +1302,7 @@ data_page); else if (flags & MS_BIND) retval = do_loopback(&nd, dev_name, flags & MS_REC); - else if (flags & (MS_SHARED | MS_PRIVATE | MS_SLAVE)) + else if (flags & (MS_SHARED | MS_PRIVATE | MS_SLAVE | MS_UNBINDABLE)) retval = do_change_type(&nd, flags); else if (flags & MS_MOVE) retval = do_move_mount(&nd, dev_name); @@ -1311,7 +1347,7 @@ down_write(&namespace_sem); /* First pass: copy the tree topology */ new_ns->root = copy_tree(namespace->root, namespace->root->mnt_root, - CL_EXPIRE); + CL_COPY_ALL | CL_EXPIRE); if (!new_ns->root) { up_write(&namespace_sem); kfree(new_ns); diff -urN FS-slave_operations/fs/pnode.c FS-unbindable_mount/fs/pnode.c --- FS-slave_operations/fs/pnode.c 2005-11-03 06:59:28.000000000 -0500 +++ FS-unbindable_mount/fs/pnode.c 2005-11-03 06:59:29.000000000 -0500 @@ -82,6 +82,8 @@ if (type != MS_SLAVE) { list_del_init(&mnt->mnt_slave); mnt->mnt_master = NULL; + if (type == MS_UNBINDABLE) + mnt->mnt_flags |= MNT_UNBINDABLE; } } diff -urN FS-slave_operations/fs/pnode.h FS-unbindable_mount/fs/pnode.h --- FS-slave_operations/fs/pnode.h 2005-11-03 06:59:27.000000000 -0500 +++ FS-unbindable_mount/fs/pnode.h 2005-11-03 06:59:29.000000000 -0500 @@ -15,6 +15,7 @@ #define IS_MNT_SLAVE(mnt) (mnt->mnt_master) #define IS_MNT_NEW(mnt) (!mnt->mnt_namespace) #define CLEAR_MNT_SHARED(mnt) (mnt->mnt_flags &= ~MNT_SHARED) +#define IS_MNT_UNBINDABLE(mnt) (mnt->mnt_flags & MNT_UNBINDABLE) #define CL_EXPIRE 0x01 #define CL_SLAVE 0x02 diff -urN FS-slave_operations/include/linux/fs.h FS-unbindable_mount/include/linux/fs.h --- FS-slave_operations/include/linux/fs.h 2005-11-03 06:59:27.000000000 -0500 +++ FS-unbindable_mount/include/linux/fs.h 2005-11-03 06:59:29.000000000 -0500 @@ -104,6 +104,7 @@ #define MS_MOVE 8192 #define MS_REC 16384 #define MS_VERBOSE 32768 +#define MS_UNBINDABLE (1<<17) /* change to unbindable */ #define MS_PRIVATE (1<<18) /* change to private */ #define MS_SLAVE (1<<19) /* change to slave */ #define MS_SHARED (1<<20) /* change to shared */ diff -urN FS-slave_operations/include/linux/mount.h FS-unbindable_mount/include/linux/mount.h --- FS-slave_operations/include/linux/mount.h 2005-11-03 06:59:27.000000000 -0500 +++ FS-unbindable_mount/include/linux/mount.h 2005-11-03 06:59:29.000000000 -0500 @@ -21,6 +21,7 @@ #define MNT_NODEV 0x02 #define MNT_NOEXEC 0x04 #define MNT_SHARED 0x10 /* if the vfsmount is a shared mount */ +#define MNT_UNBINDABLE 0x20 /* if the vfsmount is a unbindable mount */ #define MNT_PNODE_MASK 0x30 /* propogation flag mask */ struct vfsmount {