Re: [PATCH] tracefs/eventfs: Use root and instance inodes as default ownership

On Wed, 10 Jan 2024 08:07:46 -0500
Steven Rostedt [off-list ref] wrote:

Or are you saying that I don't need the ".permission" callback, because
eventfs does it when it creates the inodes? But for eventfs to know what
the permissions changes are, it uses .getattr and .setattr.

OK, if your main argument is that we do not need .permission, I agree with
you. But that's a trivial change and doesn't affect the complexity that
eventfs is doing. In fact, removing the "permission" check is simply this
patch:

--

diff --git a/fs/tracefs/event_inode.c b/fs/tracefs/event_inode.c
index fdff53d5a1f8..f2af07a857e2 100644
--- a/fs/tracefs/event_inode.c
+++ b/fs/tracefs/event_inode.c

@@ -192,18 +192,10 @@ static int eventfs_get_attr(struct mnt_idmap *idmap,
 	return 0;
 }
 
-static int eventfs_permission(struct mnt_idmap *idmap,
-			      struct inode *inode, int mask)
-{
-	set_top_events_ownership(inode);
-	return generic_permission(idmap, inode, mask);
-}
-
 static const struct inode_operations eventfs_root_dir_inode_operations = {
 	.lookup		= eventfs_root_lookup,
 	.setattr	= eventfs_set_attr,
 	.getattr	= eventfs_get_attr,
-	.permission	= eventfs_permission,
 };
 
 static const struct inode_operations eventfs_file_inode_operations = {
--

I only did that because Linus mentioned it, and I thought it was needed.
I'll apply this patch too, as it appears to work with this code.

Thanks!

-- Steve