fs: umount on symlink leaks mnt count Currently umount on symlink blocks following umount: /vz is separate mount # ls /vz/ -al | grep test drwxr-xr-x. 2 root root 4096 Jul 19 01:14 testdir lrwxrwxrwx. 1 root root 11 Jul 19 01:16 testlink -> /vz/testdir # umount -l /vz/testlink umount: /vz/testlink: not mounted (expected) # lsof /vz # umount /vz umount: /vz: device is busy. (unexpected) In this case mountpoint_last() gets an extra refcount on path->mnt diff --git a/fs/namei.c b/fs/namei.c index 985c6f3..9eb787e 100644 --- a/fs/namei.c +++ b/fs/namei.c @@ -2256,9 +2256,10 @@ done: goto out; } path->dentry = dentry; - path->mnt = mntget(nd->path.mnt); + path->mnt = nd->path.mnt; if (should_follow_link(dentry, nd->flags & LOOKUP_FOLLOW)) return 1; + mntget(path->mnt); follow_mount(path); error = 0; out: