ANDROID: mnt: Propagate remount correctly

This switches over to propagation_next to respect
namepsace semantics.

Test: Remounting to change the options of a fs with mount based
      options should propagate to all shared copies of that mount,
      and the slaves/indirect slaves of those.
Bug: 122428178
Signed-off-by: Daniel Rosenberg <drosen@google.com>
Change-Id: Ic35cd2782a646435689f5bedfa1f218fe4ab8254

1 files changed, 8 insertions, 26 deletions

diff --git a/fs/pnode.c b/fs/pnode.c
index 7f11e46d4418..6a7960537945 100644
--- a/fs/pnode.c
+++ b/fs/pnode.c
@@ -609,36 +609,18 @@ int propagate_umount(struct list_head *list)
 	return 0;
 }
 
-/*
- *  Iterates over all slaves, and slaves of slaves.
- */
-static struct mount *next_descendent(struct mount *root, struct mount *cur)
-{
-	if (!IS_MNT_NEW(cur) && !list_empty(&cur->mnt_slave_list))
-		return first_slave(cur);
-	do {
-		struct mount *master = cur->mnt_master;
-
-		if (!master || cur->mnt_slave.next != &master->mnt_slave_list) {
-			struct mount *next = next_slave(cur);
-
-			return (next == root) ? NULL : next;
-		}
-		cur = master;
-	} while (cur != root);
-	return NULL;
-}
-
 void propagate_remount(struct mount *mnt)
 {
-	struct mount *m = mnt;
+	struct mount *parent = mnt->mnt_parent;
+	struct mount *p = mnt, *m;
 	struct super_block *sb = mnt->mnt.mnt_sb;
 
-	if (sb->s_op->copy_mnt_data) {
-		m = next_descendent(mnt, m);
-		while (m) {
+	if (!sb->s_op->copy_mnt_data)
+		return;
+	for (p = propagation_next(parent, parent); p;
+				p = propagation_next(p, parent)) {
+		m = __lookup_mnt(&p->mnt, mnt->mnt_mountpoint);
+		if (m)
 			sb->s_op->copy_mnt_data(m->mnt.data, mnt->mnt.data);
-			m = next_descendent(mnt, m);
-		}
 	}
 }