* Author : Ram Pai (linuxram@us.ibm.com)
*
*/
-#include <linux/namespace.h>
+#include <linux/mnt_namespace.h>
#include <linux/mount.h>
#include <linux/fs.h>
+#include <linux/nsproxy.h>
+#include "internal.h"
#include "pnode.h"
/* return the next shared peer mount of @p */
-static inline struct vfsmount *next_peer(struct vfsmount *p)
+static inline struct mount *next_peer(struct mount *p)
{
- return list_entry(p->mnt_share.next, struct vfsmount, mnt_share);
+ return list_entry(p->mnt_share.next, struct mount, mnt_share);
}
-static inline struct vfsmount *first_slave(struct vfsmount *p)
+static inline struct mount *first_slave(struct mount *p)
{
- return list_entry(p->mnt_slave_list.next, struct vfsmount, mnt_slave);
+ return list_entry(p->mnt_slave_list.next, struct mount, mnt_slave);
}
-static inline struct vfsmount *next_slave(struct vfsmount *p)
+static inline struct mount *next_slave(struct mount *p)
{
- return list_entry(p->mnt_slave.next, struct vfsmount, mnt_slave);
+ return list_entry(p->mnt_slave.next, struct mount, mnt_slave);
}
-static int do_make_slave(struct vfsmount *mnt)
+static struct mount *get_peer_under_root(struct mount *mnt,
+ struct mnt_namespace *ns,
+ const struct path *root)
{
- struct vfsmount *peer_mnt = mnt, *master = mnt->mnt_master;
- struct vfsmount *slave_mnt;
+ struct mount *m = mnt;
+
+ do {
+ /* Check the namespace first for optimization */
+ if (m->mnt_ns == ns && is_path_reachable(m, m->mnt.mnt_root, root))
+ return m;
+
+ m = next_peer(m);
+ } while (m != mnt);
+
+ return NULL;
+}
+
+/*
+ * Get ID of closest dominating peer group having a representative
+ * under the given root.
+ *
+ * Caller must hold namespace_sem
+ */
+int get_dominating_id(struct mount *mnt, const struct path *root)
+{
+ struct mount *m;
+
+ for (m = mnt->mnt_master; m != NULL; m = m->mnt_master) {
+ struct mount *d = get_peer_under_root(m, mnt->mnt_ns, root);
+ if (d)
+ return d->mnt_group_id;
+ }
+
+ return 0;
+}
+
+static int do_make_slave(struct mount *mnt)
+{
+ struct mount *peer_mnt = mnt, *master = mnt->mnt_master;
+ struct mount *slave_mnt;
/*
* slave 'mnt' to a peer mount that has the
- * same root dentry. If none is available than
+ * same root dentry. If none is available then
* slave it to anything that is available.
*/
while ((peer_mnt = next_peer(peer_mnt)) != mnt &&
- peer_mnt->mnt_root != mnt->mnt_root) ;
+ peer_mnt->mnt.mnt_root != mnt->mnt.mnt_root) ;
if (peer_mnt == mnt) {
peer_mnt = next_peer(mnt);
if (peer_mnt == mnt)
peer_mnt = NULL;
}
+ if (mnt->mnt_group_id && IS_MNT_SHARED(mnt) &&
+ list_empty(&mnt->mnt_share))
+ mnt_release_group_id(mnt);
+
list_del_init(&mnt->mnt_share);
+ mnt->mnt_group_id = 0;
if (peer_mnt)
master = peer_mnt;
if (master) {
list_for_each_entry(slave_mnt, &mnt->mnt_slave_list, mnt_slave)
slave_mnt->mnt_master = master;
- list_del(&mnt->mnt_slave);
- list_add(&mnt->mnt_slave, &master->mnt_slave_list);
+ list_move(&mnt->mnt_slave, &master->mnt_slave_list);
list_splice(&mnt->mnt_slave_list, master->mnt_slave_list.prev);
INIT_LIST_HEAD(&mnt->mnt_slave_list);
} else {
struct list_head *p = &mnt->mnt_slave_list;
while (!list_empty(p)) {
- slave_mnt = list_entry(p->next,
- struct vfsmount, mnt_slave);
+ slave_mnt = list_first_entry(p,
+ struct mount, mnt_slave);
list_del_init(&slave_mnt->mnt_slave);
slave_mnt->mnt_master = NULL;
}
}
mnt->mnt_master = master;
CLEAR_MNT_SHARED(mnt);
- INIT_LIST_HEAD(&mnt->mnt_slave_list);
return 0;
}
-void change_mnt_propagation(struct vfsmount *mnt, int type)
+/*
+ * vfsmount lock must be held for write
+ */
+void change_mnt_propagation(struct mount *mnt, int type)
{
if (type == MS_SHARED) {
set_mnt_shared(mnt);
list_del_init(&mnt->mnt_slave);
mnt->mnt_master = NULL;
if (type == MS_UNBINDABLE)
- mnt->mnt_flags |= MNT_UNBINDABLE;
+ mnt->mnt.mnt_flags |= MNT_UNBINDABLE;
+ else
+ mnt->mnt.mnt_flags &= ~MNT_UNBINDABLE;
}
}
* get the next mount in the propagation tree.
* @m: the mount seen last
* @origin: the original mount from where the tree walk initiated
+ *
+ * Note that peer groups form contiguous segments of slave lists.
+ * We rely on that in get_source() to be able to find out if
+ * vfsmount found while iterating with propagation_next() is
+ * a peer of one we'd found earlier.
*/
-static struct vfsmount *propagation_next(struct vfsmount *m,
- struct vfsmount *origin)
+static struct mount *propagation_next(struct mount *m,
+ struct mount *origin)
{
/* are there any slaves of this mount? */
if (!IS_MNT_NEW(m) && !list_empty(&m->mnt_slave_list))
return first_slave(m);
while (1) {
- struct vfsmount *next;
- struct vfsmount *master = m->mnt_master;
+ struct mount *master = m->mnt_master;
if (master == origin->mnt_master) {
- next = next_peer(m);
- return ((next == origin) ? NULL : next);
+ struct mount *next = next_peer(m);
+ return (next == origin) ? NULL : next;
} else if (m->mnt_slave.next != &master->mnt_slave_list)
return next_slave(m);
* @type return CL_SLAVE if the new mount has to be
* cloned as a slave.
*/
-static struct vfsmount *get_source(struct vfsmount *dest,
- struct vfsmount *last_dest,
- struct vfsmount *last_src,
- int *type)
+static struct mount *get_source(struct mount *dest,
+ struct mount *last_dest,
+ struct mount *last_src,
+ int *type)
{
- struct vfsmount *p_last_src = NULL;
- struct vfsmount *p_last_dest = NULL;
- *type = CL_PROPAGATION;
-
- if (IS_MNT_SHARED(dest))
- *type |= CL_MAKE_SHARED;
+ struct mount *p_last_src = NULL;
+ struct mount *p_last_dest = NULL;
while (last_dest != dest->mnt_master) {
p_last_dest = 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;
+ }
}
-
- if (dest != p_last_dest) {
- *type |= CL_SLAVE;
- return last_src;
- } else
- return p_last_src;
+ /* 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;
}
/*
* @source_mnt: source mount.
* @tree_list : list of heads of trees to be attached.
*/
-int propagate_mnt(struct vfsmount *dest_mnt, struct dentry *dest_dentry,
- struct vfsmount *source_mnt, struct list_head *tree_list)
+int propagate_mnt(struct mount *dest_mnt, struct mountpoint *dest_mp,
+ struct mount *source_mnt, struct list_head *tree_list)
{
- struct vfsmount *m, *child;
+ struct user_namespace *user_ns = current->nsproxy->mnt_ns->user_ns;
+ struct mount *m, *child;
int ret = 0;
- struct vfsmount *prev_dest_mnt = dest_mnt;
- struct vfsmount *prev_src_mnt = source_mnt;
+ struct mount *prev_dest_mnt = dest_mnt;
+ struct mount *prev_src_mnt = source_mnt;
LIST_HEAD(tmp_list);
- LIST_HEAD(umount_list);
for (m = propagation_next(dest_mnt, dest_mnt); m;
m = propagation_next(m, dest_mnt)) {
int type;
- struct vfsmount *source;
+ struct mount *source;
if (IS_MNT_NEW(m))
continue;
source = get_source(m, prev_dest_mnt, prev_src_mnt, &type);
- if (!(child = copy_tree(source, source->mnt_root, type))) {
- ret = -ENOMEM;
+ /* 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);
list_splice(tree_list, tmp_list.prev);
goto out;
}
- if (is_subdir(dest_dentry, m->mnt_root)) {
- mnt_set_mountpoint(m, dest_dentry, child);
+ if (is_subdir(dest_mp->m_dentry, m->mnt.mnt_root)) {
+ mnt_set_mountpoint(m, dest_mp, child);
list_add_tail(&child->mnt_hash, tree_list);
} else {
/*
prev_src_mnt = child;
}
out:
- spin_lock(&vfsmount_lock);
+ br_write_lock(&vfsmount_lock);
while (!list_empty(&tmp_list)) {
- child = list_entry(tmp_list.next, struct vfsmount, mnt_hash);
- list_del_init(&child->mnt_hash);
- umount_tree(child, 0, &umount_list);
+ child = list_first_entry(&tmp_list, struct mount, mnt_hash);
+ umount_tree(child, 0);
}
- spin_unlock(&vfsmount_lock);
- release_mounts(&umount_list);
+ br_write_unlock(&vfsmount_lock);
return ret;
}
/*
* return true if the refcount is greater than count
*/
-static inline int do_refcount_check(struct vfsmount *mnt, int count)
+static inline int do_refcount_check(struct mount *mnt, int count)
{
- int mycount = atomic_read(&mnt->mnt_count);
+ int mycount = mnt_get_count(mnt) - mnt->mnt_ghosts;
return (mycount > count);
}
* other mounts its parent propagates to.
* Check if any of these mounts that **do not have submounts**
* have more references than 'refcnt'. If so return busy.
+ *
+ * vfsmount lock must be held for write
*/
-int propagate_mount_busy(struct vfsmount *mnt, int refcnt)
+int propagate_mount_busy(struct mount *mnt, int refcnt)
{
- struct vfsmount *m, *child;
- struct vfsmount *parent = mnt->mnt_parent;
+ struct mount *m, *child;
+ struct mount *parent = mnt->mnt_parent;
int ret = 0;
if (mnt == parent)
for (m = propagation_next(parent, parent); m;
m = propagation_next(m, parent)) {
- child = __lookup_mnt(m, mnt->mnt_mountpoint, 0);
+ child = __lookup_mnt(&m->mnt, mnt->mnt_mountpoint, 0);
if (child && list_empty(&child->mnt_mounts) &&
(ret = do_refcount_check(child, 1)))
break;
* NOTE: unmounting 'mnt' naturally propagates to all other mounts its
* parent propagates to.
*/
-static void __propagate_umount(struct vfsmount *mnt)
+static void __propagate_umount(struct mount *mnt)
{
- struct vfsmount *parent = mnt->mnt_parent;
- struct vfsmount *m;
+ struct mount *parent = mnt->mnt_parent;
+ struct mount *m;
BUG_ON(parent == mnt);
for (m = propagation_next(parent, parent); m;
m = propagation_next(m, parent)) {
- struct vfsmount *child = __lookup_mnt(m,
+ struct mount *child = __lookup_mnt(&m->mnt,
mnt->mnt_mountpoint, 0);
/*
* umount the child only if the child has no
* other children
*/
- if (child && list_empty(&child->mnt_mounts)) {
- list_del(&child->mnt_hash);
- list_add_tail(&child->mnt_hash, &mnt->mnt_hash);
- }
+ if (child && list_empty(&child->mnt_mounts))
+ list_move_tail(&child->mnt_hash, &mnt->mnt_hash);
}
}
* collect all mounts that receive propagation from the mount in @list,
* and return these additional mounts in the same list.
* @list: the list of mounts to be unmounted.
+ *
+ * vfsmount lock must be held for write
*/
int propagate_umount(struct list_head *list)
{
- struct vfsmount *mnt;
+ struct mount *mnt;
list_for_each_entry(mnt, list, mnt_hash)
__propagate_umount(mnt);
Code Review / linux-3.10.git / blobdiff