Re: [PATCH 5/8] vfs: Include origin of the SB error notification

David Howells
2020-12-08T12:52:59Z

Gabriel Krisman Bertazi <krisman@collabora.com> wrote:

> @@ -130,6 +131,8 @@ struct superblock_error_notification {
> __u32 error_cookie;
> __u64 inode;
> __u64 block;
> + char function[SB_NOTIFICATION_FNAME_LEN];
> + __u16 line;
> char desc[0];
> };

As Darrick said, this is a UAPI breaker, so you shouldn't do this (you can,
however, merge this ahead a patch). Also, I would put the __u16 before the
char[].

That said, I'm not sure whether it's useful to include the function name and
line. Both fields are liable to change over kernel commits, so it's not
something userspace can actually interpret. I think you're better off dumping
those into dmesg.

Further, this reduces the capacity of desc[] significantly - I don't know if
that's a problem.

And yet further, there's no room for addition of new fields with the desc[]
buffer on the end. Now maybe you're planning on making use of desc[] for
text-encoding?

David