ASR_BASE
Change-Id: Icf3719cc0afe3eeb3edc7fa80a2eb5199ca9dda1
diff --git a/marvell/linux/fs/pnode.c b/marvell/linux/fs/pnode.c
new file mode 100644
index 0000000..468e4e6
--- /dev/null
+++ b/marvell/linux/fs/pnode.c
@@ -0,0 +1,602 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * linux/fs/pnode.c
+ *
+ * (C) Copyright IBM Corporation 2005.
+ * Author : Ram Pai (linuxram@us.ibm.com)
+ */
+#include <linux/mnt_namespace.h>
+#include <linux/mount.h>
+#include <linux/fs.h>
+#include <linux/nsproxy.h>
+#include <uapi/linux/mount.h>
+#include "internal.h"
+#include "pnode.h"
+
+/* return the next shared peer mount of @p */
+static inline struct mount *next_peer(struct mount *p)
+{
+ return list_entry(p->mnt_share.next, struct mount, mnt_share);
+}
+
+static inline struct mount *first_slave(struct mount *p)
+{
+ return list_entry(p->mnt_slave_list.next, struct mount, mnt_slave);
+}
+
+static inline struct mount *last_slave(struct mount *p)
+{
+ return list_entry(p->mnt_slave_list.prev, struct mount, mnt_slave);
+}
+
+static inline struct mount *next_slave(struct mount *p)
+{
+ return list_entry(p->mnt_slave.next, struct mount, mnt_slave);
+}
+
+static struct mount *get_peer_under_root(struct mount *mnt,
+ struct mnt_namespace *ns,
+ const struct path *root)
+{
+ 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 *master, *slave_mnt;
+
+ if (list_empty(&mnt->mnt_share)) {
+ if (IS_MNT_SHARED(mnt)) {
+ mnt_release_group_id(mnt);
+ CLEAR_MNT_SHARED(mnt);
+ }
+ master = mnt->mnt_master;
+ if (!master) {
+ struct list_head *p = &mnt->mnt_slave_list;
+ while (!list_empty(p)) {
+ slave_mnt = list_first_entry(p,
+ struct mount, mnt_slave);
+ list_del_init(&slave_mnt->mnt_slave);
+ slave_mnt->mnt_master = NULL;
+ }
+ return 0;
+ }
+ } else {
+ struct mount *m;
+ /*
+ * slave 'mnt' to a peer mount that has the
+ * same root dentry. If none is available then
+ * slave it to anything that is available.
+ */
+ for (m = master = next_peer(mnt); m != mnt; m = next_peer(m)) {
+ if (m->mnt.mnt_root == mnt->mnt.mnt_root) {
+ master = m;
+ break;
+ }
+ }
+ list_del_init(&mnt->mnt_share);
+ mnt->mnt_group_id = 0;
+ CLEAR_MNT_SHARED(mnt);
+ }
+ list_for_each_entry(slave_mnt, &mnt->mnt_slave_list, mnt_slave)
+ slave_mnt->mnt_master = master;
+ 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);
+ mnt->mnt_master = master;
+ return 0;
+}
+
+/*
+ * vfsmount lock must be held for write
+ */
+void change_mnt_propagation(struct mount *mnt, int type)
+{
+ if (type == MS_SHARED) {
+ set_mnt_shared(mnt);
+ return;
+ }
+ do_make_slave(mnt);
+ if (type != MS_SLAVE) {
+ list_del_init(&mnt->mnt_slave);
+ mnt->mnt_master = NULL;
+ if (type == MS_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 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 mount *master = m->mnt_master;
+
+ if (master == origin->mnt_master) {
+ 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);
+
+ /* back at master */
+ m = master;
+ }
+}
+
+static struct mount *skip_propagation_subtree(struct mount *m,
+ struct mount *origin)
+{
+ /*
+ * Advance m such that propagation_next will not return
+ * the slaves of m.
+ */
+ if (!IS_MNT_NEW(m) && !list_empty(&m->mnt_slave_list))
+ m = last_slave(m);
+
+ return m;
+}
+
+static struct mount *next_group(struct mount *m, struct mount *origin)
+{
+ 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;
+ }
+}
+
+/* all accesses are serialized by namespace_sem */
+static struct mount *last_dest, *first_source, *last_source, *dest_master;
+static struct mountpoint *mp;
+static struct hlist_head *list;
+
+static inline bool peers(struct mount *m1, struct mount *m2)
+{
+ return m1->mnt_group_id == m2->mnt_group_id && m1->mnt_group_id;
+}
+
+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 (peers(m, last_dest)) {
+ type = CL_MAKE_SHARED;
+ } else {
+ struct mount *n, *p;
+ bool done;
+ for (n = m; ; n = p) {
+ p = n->mnt_master;
+ if (p == dest_master || IS_MNT_MARKED(p))
+ break;
+ }
+ do {
+ struct mount *parent = last_source->mnt_parent;
+ if (peers(last_source, first_source))
+ break;
+ done = parent->mnt_master == p;
+ if (done && peers(n, parent))
+ break;
+ last_source = last_source->mnt_master;
+ } while (!done);
+
+ type = CL_SLAVE;
+ /* beginning of peer group among the slaves? */
+ if (IS_MNT_SHARED(m))
+ type |= CL_MAKE_SHARED;
+ }
+
+ child = copy_tree(last_source, last_source->mnt.mnt_root, type);
+ if (IS_ERR(child))
+ return PTR_ERR(child);
+ read_seqlock_excl(&mount_lock);
+ mnt_set_mountpoint(m, mp, child);
+ if (m->mnt_master != dest_master)
+ SET_MNT_MARK(m->mnt_master);
+ read_sequnlock_excl(&mount_lock);
+ last_dest = m;
+ last_source = child;
+ hlist_add_head(&child->mnt_hash, list);
+ return count_mounts(m->mnt_ns, child);
+}
+
+/*
+ * mount 'source_mnt' under the destination 'dest_mnt' at
+ * dentry 'dest_dentry'. And propagate that mount to
+ * all the peer and slave mounts of 'dest_mnt'.
+ * Link all the new mounts into a propagation tree headed at
+ * source_mnt. Also link all the new mounts using ->mnt_list
+ * headed at source_mnt's ->mnt_list
+ *
+ * @dest_mnt: destination mount.
+ * @dest_dentry: destination dentry.
+ * @source_mnt: source mount.
+ * @tree_list : list of heads of trees to be attached.
+ */
+int propagate_mnt(struct mount *dest_mnt, struct mountpoint *dest_mp,
+ struct mount *source_mnt, struct hlist_head *tree_list)
+{
+ struct mount *m, *n;
+ int ret = 0;
+
+ /*
+ * 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.
+ */
+ last_dest = dest_mnt;
+ first_source = source_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;
+ }
+
+ /* 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:
+ 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);
+ }
+ read_sequnlock_excl(&mount_lock);
+ return ret;
+}
+
+static struct mount *find_topper(struct mount *mnt)
+{
+ /* If there is exactly one mount covering mnt completely return it. */
+ struct mount *child;
+
+ if (!list_is_singular(&mnt->mnt_mounts))
+ return NULL;
+
+ child = list_first_entry(&mnt->mnt_mounts, struct mount, mnt_child);
+ if (child->mnt_mountpoint != mnt->mnt.mnt_root)
+ return NULL;
+
+ return child;
+}
+
+/*
+ * return true if the refcount is greater than count
+ */
+static inline int do_refcount_check(struct mount *mnt, int count)
+{
+ return mnt_get_count(mnt) > count;
+}
+
+/*
+ * check if the mount 'mnt' can be unmounted successfully.
+ * @mnt: the mount to be checked for unmount
+ * NOTE: unmounting 'mnt' would naturally propagate to all
+ * 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 mount *mnt, int refcnt)
+{
+ struct mount *m, *child, *topper;
+ struct mount *parent = mnt->mnt_parent;
+
+ if (mnt == parent)
+ return do_refcount_check(mnt, refcnt);
+
+ /*
+ * quickly check if the current mount can be unmounted.
+ * If not, we don't have to go checking for all other
+ * mounts
+ */
+ if (!list_empty(&mnt->mnt_mounts) || do_refcount_check(mnt, refcnt))
+ return 1;
+
+ for (m = propagation_next(parent, parent); m;
+ m = propagation_next(m, parent)) {
+ int count = 1;
+ child = __lookup_mnt(&m->mnt, mnt->mnt_mountpoint);
+ if (!child)
+ continue;
+
+ /* Is there exactly one mount on the child that covers
+ * it completely whose reference should be ignored?
+ */
+ topper = find_topper(child);
+ if (topper)
+ count += 1;
+ else if (!list_empty(&child->mnt_mounts))
+ continue;
+
+ if (do_refcount_check(child, count))
+ return 1;
+ }
+ return 0;
+}
+
+/*
+ * Clear MNT_LOCKED when it can be shown to be safe.
+ *
+ * mount_lock lock must be held for write
+ */
+void propagate_mount_unlock(struct mount *mnt)
+{
+ struct mount *parent = mnt->mnt_parent;
+ struct mount *m, *child;
+
+ BUG_ON(parent == mnt);
+
+ for (m = propagation_next(parent, parent); m;
+ m = propagation_next(m, parent)) {
+ child = __lookup_mnt(&m->mnt, mnt->mnt_mountpoint);
+ if (child)
+ child->mnt.mnt_flags &= ~MNT_LOCKED;
+ }
+}
+
+static void umount_one(struct mount *mnt, struct list_head *to_umount)
+{
+ CLEAR_MNT_MARK(mnt);
+ mnt->mnt.mnt_flags |= MNT_UMOUNT;
+ list_del_init(&mnt->mnt_child);
+ list_del_init(&mnt->mnt_umounting);
+ list_move_tail(&mnt->mnt_list, to_umount);
+}
+
+/*
+ * NOTE: unmounting 'mnt' naturally propagates to all other mounts its
+ * parent propagates to.
+ */
+static bool __propagate_umount(struct mount *mnt,
+ struct list_head *to_umount,
+ struct list_head *to_restore)
+{
+ bool progress = false;
+ struct mount *child;
+
+ /*
+ * The state of the parent won't change if this mount is
+ * already unmounted or marked as without children.
+ */
+ if (mnt->mnt.mnt_flags & (MNT_UMOUNT | MNT_MARKED))
+ goto out;
+
+ /* Verify topper is the only grandchild that has not been
+ * speculatively unmounted.
+ */
+ list_for_each_entry(child, &mnt->mnt_mounts, mnt_child) {
+ if (child->mnt_mountpoint == mnt->mnt.mnt_root)
+ continue;
+ if (!list_empty(&child->mnt_umounting) && IS_MNT_MARKED(child))
+ continue;
+ /* Found a mounted child */
+ goto children;
+ }
+
+ /* Mark mounts that can be unmounted if not locked */
+ SET_MNT_MARK(mnt);
+ progress = true;
+
+ /* If a mount is without children and not locked umount it. */
+ if (!IS_MNT_LOCKED(mnt)) {
+ umount_one(mnt, to_umount);
+ } else {
+children:
+ list_move_tail(&mnt->mnt_umounting, to_restore);
+ }
+out:
+ return progress;
+}
+
+static void umount_list(struct list_head *to_umount,
+ struct list_head *to_restore)
+{
+ struct mount *mnt, *child, *tmp;
+ list_for_each_entry(mnt, to_umount, mnt_list) {
+ list_for_each_entry_safe(child, tmp, &mnt->mnt_mounts, mnt_child) {
+ /* topper? */
+ if (child->mnt_mountpoint == mnt->mnt.mnt_root)
+ list_move_tail(&child->mnt_umounting, to_restore);
+ else
+ umount_one(child, to_umount);
+ }
+ }
+}
+
+static void restore_mounts(struct list_head *to_restore)
+{
+ /* Restore mounts to a clean working state */
+ while (!list_empty(to_restore)) {
+ struct mount *mnt, *parent;
+ struct mountpoint *mp;
+
+ mnt = list_first_entry(to_restore, struct mount, mnt_umounting);
+ CLEAR_MNT_MARK(mnt);
+ list_del_init(&mnt->mnt_umounting);
+
+ /* Should this mount be reparented? */
+ mp = mnt->mnt_mp;
+ parent = mnt->mnt_parent;
+ while (parent->mnt.mnt_flags & MNT_UMOUNT) {
+ mp = parent->mnt_mp;
+ parent = parent->mnt_parent;
+ }
+ if (parent != mnt->mnt_parent)
+ mnt_change_mountpoint(parent, mp, mnt);
+ }
+}
+
+static void cleanup_umount_visitations(struct list_head *visited)
+{
+ while (!list_empty(visited)) {
+ struct mount *mnt =
+ list_first_entry(visited, struct mount, mnt_umounting);
+ list_del_init(&mnt->mnt_umounting);
+ }
+}
+
+/*
+ * 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 mount *mnt;
+ LIST_HEAD(to_restore);
+ LIST_HEAD(to_umount);
+ LIST_HEAD(visited);
+
+ /* Find candidates for unmounting */
+ list_for_each_entry_reverse(mnt, list, mnt_list) {
+ struct mount *parent = mnt->mnt_parent;
+ struct mount *m;
+
+ /*
+ * If this mount has already been visited it is known that it's
+ * entire peer group and all of their slaves in the propagation
+ * tree for the mountpoint has already been visited and there is
+ * no need to visit them again.
+ */
+ if (!list_empty(&mnt->mnt_umounting))
+ continue;
+
+ list_add_tail(&mnt->mnt_umounting, &visited);
+ for (m = propagation_next(parent, parent); m;
+ m = propagation_next(m, parent)) {
+ struct mount *child = __lookup_mnt(&m->mnt,
+ mnt->mnt_mountpoint);
+ if (!child)
+ continue;
+
+ if (!list_empty(&child->mnt_umounting)) {
+ /*
+ * If the child has already been visited it is
+ * know that it's entire peer group and all of
+ * their slaves in the propgation tree for the
+ * mountpoint has already been visited and there
+ * is no need to visit this subtree again.
+ */
+ m = skip_propagation_subtree(m, parent);
+ continue;
+ } else if (child->mnt.mnt_flags & MNT_UMOUNT) {
+ /*
+ * We have come accross an partially unmounted
+ * mount in list that has not been visited yet.
+ * Remember it has been visited and continue
+ * about our merry way.
+ */
+ list_add_tail(&child->mnt_umounting, &visited);
+ continue;
+ }
+
+ /* Check the child and parents while progress is made */
+ while (__propagate_umount(child,
+ &to_umount, &to_restore)) {
+ /* Is the parent a umount candidate? */
+ child = child->mnt_parent;
+ if (list_empty(&child->mnt_umounting))
+ break;
+ }
+ }
+ }
+
+ umount_list(&to_umount, &to_restore);
+ restore_mounts(&to_restore);
+ cleanup_umount_visitations(&visited);
+ list_splice_tail(&to_umount, list);
+
+ return 0;
+}