Revert "eventfs: Do not allow NULL parent to eventfs_start_creating()"

This reverts commit 6abb8c223ce12078a0f2c129656a13338dfe960b.

The eventfs was not designed properly and may have some hidden bugs in it.
Linus rewrote it properly and I trust his version more than this one. Revert
the backported patches for 6.6 and re-apply all the changes to make it
equivalent to Linus's version.

Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/fs/tracefs/inode.c b/fs/tracefs/inode.c
index 0292c6a2bed9f2b2c237ac8f3d1e89c3fb9dc271..891653ba9cf35863f5cc83638b2a2a9a88a03444 100644 (file)
--- a/fs/tracefs/inode.c
+++ b/fs/tracefs/inode.c
@@ -509,15 +509,20 @@ struct dentry *eventfs_start_creating(const char *name, struct dentry *parent)
        struct dentry *dentry;
        int error;
 
-       /* Must always have a parent. */
-       if (WARN_ON_ONCE(!parent))
-               return ERR_PTR(-EINVAL);
-
        error = simple_pin_fs(&trace_fs_type, &tracefs_mount,
                              &tracefs_mount_count);
        if (error)
                return ERR_PTR(error);
 
+       /*
+        * If the parent is not specified, we create it in the root.
+        * We need the root dentry to do this, which is in the super
+        * block. A pointer to that is in the struct vfsmount that we
+        * have around.
+        */
+       if (!parent)
+               parent = tracefs_mount->mnt_root;
+
        if (unlikely(IS_DEADDIR(parent->d_inode)))
                dentry = ERR_PTR(-ENOENT);
        else