Re: [PATCH V2] fs_parser: remove fs_parameter_description name field

[Al Viro <viro@zeniv.linux.org.uk>]

On Fri, Dec 06, 2019 at 10:31:57AM -0600, Eric Sandeen wrote:
> There doesn't seem to be a strong reason to have a copy of the
> filesystem name string in the fs_parameter_description structure;
> it's easy enough to get the name from the fs_type, and using it
> instead ensures consistency across messages (for example,
> vfs_parse_fs_param() already uses fc->fs_type->name for the error
> messages, because it doesn't have the fs_parameter_description).

Arrgh...  That used to be fine.  Now we have this:
static int rbd_parse_param(struct fs_parameter *param,
                            struct rbd_parse_opts_ctx *pctx)
{
        struct rbd_options *opt = pctx->opts;
        struct fs_parse_result result; 
        int token, ret;

        ret = ceph_parse_param(param, pctx->copts, NULL);
        if (ret != -ENOPARAM)
                return ret;

        token = fs_parse(NULL, rbd_parameters, param, &result);
			 ^^^^

	Cthulhu damn it...  And yes, that crap used to work.
Frankly, I'm tempted to allocate fs_context in there (in
rbd_parse_options(), or in rbd_add_parse_args()) - we've other
oddities due to that...

	Alternatively, we could provide __fs_parse() that
would take name as a separate argument and accepted NULL fc,
with fs_parse() being a wrapper for that.

*grumble*