Revert "kernfs: remove kernfs_addrm_cxt"

This reverts commit 99177a34110889a8f2c36420c34e3bcc9bfd8a70.

Tejun writes:
        I'm sorry but can you please revert the whole series?
        get_active() waiting while a node is deactivated has potential
        to lead to deadlock and that deactivate/reactivate interface is
        something fundamentally flawed and that cgroup will have to work
        with the remove_self() like everybody else.  IOW, I think the
        first posting was correct.

Cc: Tejun Heo <tj@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

1 files changed, 9 insertions, 1 deletions

diff --git a/fs/kernfs/file.c b/fs/kernfs/file.c
index ffe1bebf9197..404ffd2f27bc 100644
--- a/fs/kernfs/file.c
+++ b/fs/kernfs/file.c
@@ -817,6 +817,7 @@ struct kernfs_node *__kernfs_create_file(struct kernfs_node *parent,
                                          bool name_is_static,
                                          struct lock_class_key *key)
 {
+        struct kernfs_addrm_cxt acxt;
         struct kernfs_node *kn;
         unsigned flags;
         int rc;
@@ -852,7 +853,14 @@ struct kernfs_node *__kernfs_create_file(struct kernfs_node *parent,
         if (ops->mmap)
                 kn->flags |= KERNFS_HAS_MMAP;
 
-        rc = kernfs_add_one(kn, parent);
+        rc = -ENOENT;
+        if (kernfs_get_active(parent)) {
+                kernfs_addrm_start(&acxt);
+                rc = kernfs_add_one(&acxt, kn, parent);
+                kernfs_addrm_finish(&acxt);
+                kernfs_put_active(parent);
+        }
+
         if (rc) {
                 kernfs_put(kn);
                 return ERR_PTR(rc);