diff options
| author | Al Viro <viro@zeniv.linux.org.uk> | 2025-08-14 23:32:26 -0400 |
|---|---|---|
| committer | Al Viro <viro@zeniv.linux.org.uk> | 2025-08-19 12:00:07 -0400 |
| commit | da025cdb97a23c1916d8491925b878f3e1de0bca (patch) | |
| tree | 63cec32b7b9a1211bc67df47e6837f556fc87828 | |
| parent | 0ddfb62f5d018edcb571a3d8ea30ad5332cf2a69 (diff) | |
propagate_umount(): only surviving overmounts should be reparented
... as the comments in reparent() clearly say. As it is, we reparent
*all* overmounts of the mounts being taken out, including those that
are taken out themselves. It's not only a potentially massive slowdown
(on a pathological setup we might end up with O(N^2) time for N mounts
being kicked out), it can end up with incorrect ->overmount in the
surviving mounts.
Fixes: f0d0ba19985d "Rewrite of propagate_umount()"
Reviewed-by: Christian Brauner <brauner@kernel.org>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
| -rw-r--r-- | fs/pnode.c | 7 |
1 files changed, 4 insertions, 3 deletions
diff --git a/fs/pnode.c b/fs/pnode.c index 81f7599bdac4..1c789f88b3d2 100644 --- a/fs/pnode.c +++ b/fs/pnode.c @@ -637,10 +637,11 @@ void propagate_umount(struct list_head *set) } // now to_umount consists of all acceptable candidates - // deal with reparenting of remaining overmounts on those + // deal with reparenting of surviving overmounts on those list_for_each_entry(m, &to_umount, mnt_list) { - if (m->overmount) - reparent(m->overmount); + struct mount *over = m->overmount; + if (over && !will_be_unmounted(over)) + reparent(over); } // and fold them into the set |