When moving a union mount, follow it down to the bottom layer and move that instead of just the top layer. Signed-off-by: Valerie Aurora <vaurora@xxxxxxxxxx> --- fs/namespace.c | 9 +++++++++ 1 files changed, 9 insertions(+), 0 deletions(-) diff --git a/fs/namespace.c b/fs/namespace.c index 9b71743..6ac5fc1 100644 --- a/fs/namespace.c +++ b/fs/namespace.c @@ -2282,6 +2282,15 @@ SYSCALL_DEFINE2(pivot_root, const char __user *, new_root, if (d_unlinked(old.dentry)) goto out2; error = -EBUSY; + /* + * follow_union_down() only goes one layer down. We want the + * bottom-most layer here - if we move that around, all the + * layers on top move with it. But if we ever allow more than + * two layers, the below two will both need to be in while() + * loops. + */ + follow_union_down(&new.mnt, &new.dentry); + follow_union_down(&root.mnt, &root.dentry); if (new.mnt == root.mnt || old.mnt == root.mnt) goto out2; /* loop, on the same file system */ -- 1.6.3.3 -- To unsubscribe from this list: send the line "unsubscribe linux-fsdevel" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
