On 10/10/2018 14:02, David Howells wrote:
The attached change seems to fix the lazy-umount problem.
David
---
diff --git a/fs/namespace.c b/fs/namespace.c
index 5adeeea2a4d9..d43f0fa152e9 100644
--- a/fs/namespace.c
+++ b/fs/namespace.c
@@ -2472,7 +2472,7 @@ static int do_move_mount(struct path *old_path, struct path *new_path)
if (old->mnt_ns && !attached)
goto out1;
- if (old->mnt.mnt_flags & MNT_LOCKED)
+ if (old->mnt.mnt_flags & (MNT_LOCKED | MNT_UMOUNT))
goto out1;
if (old_path->dentry != old_path->mnt->mnt_root)
I can't test any more at the moment, as my laptop died today :). But I
have no objection to this.
It would be more fun if there was a way to support it :), but I don't
have a genuine reason to want it. And you couldn't use it for fully
general purposes anyway, because umount2( , MNT_DETACH) is defined as
separating all the child mounts.
P.S. Regarding the issue with the namespace loop. My strawman solution
would be for graft_tree() to silently detach any NS file mounts that
have a sequence number less than or equal to the namespace they are
being mounted into.
