On Tue, Dec 17, 2019 at 01:18:13AM +0000, Al Viro wrote:
> So how about a flag for "takes no arguments", set automatically by
> fsparam_flag()/fsparam_flag_no(), with fs_lookup_key() taking an
> extra "comes with argument" flag and filtering according to it?
> Rules:
> foo => "foo", true
> foo= => "foo", false
> foo=bar => "foo", false
> And to hell with the "optional" flag; for gfs2 we'd end up with
> fsparam_flag_no("quota", Opt_quota_flag), // quota|noquota
> fsparam_flag_enum("quota", Opt_quota, gfs2_param_quota), // quota={on|account|off}
> Postprocessing won't be any harder, really - we could bloody well do
> case Opt_quota_flag:
> result.int_32 = result.negated ? GFS2_QUOTA_OFF : GFS2_QUOTA_ON;
> /* fallthru */
> case Opt_quota:
> args->ar_quota = result.int_32;
> break;
> with gfs2_param_quota having the right values in it, instead of
> that intermediate enum.
>
> All ->has_value checks go away that way, AFAICS. With minimal
> impact on yet-to-be-merged series...
FWIW, we have the following types right now:
fs_param_is_flag no argument
fs_param_is_bool no argument or string argument (1 instance in mainline[*])
fs_param_is_u32 string argument [**]
fs_param_is_u32_octal string argument
fs_param_is_u32_hex string argument
fs_param_is_s32 string argument
fs_param_is_u64 string argument
fs_param_is_enum string argument; gfs2 has the quota/noquota/quota=... mess
fs_param_is_string string argument; ceph (and nfs) have fsc/nofsc/fsc=...
fs_param_is_fd unused at the moment; eventually - string argument.
fs_param_is_blob fsconfig-only
fs_param_is_blockdev fsconfig-only
fs_param_is_path fsconfig-only
[*] no_disconnect in gadgetfs; buggered, since it used to require a numeric
argument. Now it quietly treats no_disconnect as no_disconnect=1 and
rejects e.g. no_disconnect=2. There are two more in ext4, also buggered
as far as I can tell.
[**] ext4 has init_itable/init_itable=%u/noinit_itable
The total over all filesystems with conversions posted or already in mainline:
* no_disconnect [drivers/usb/gadget/function/f_fs.c, broken]
* init_itable/init_itable=%u/noinit_itable [ext4]
* fsc/fsc=%s/nofsc [ceph]
* fsc/fsc=%s/nofsc [nfs]
* quota/quota=on/quota=off/quota=account/noquota [gfs2]
* barrier/barrier=%u/nobarrier [ext4]
* auto_da_alloc/auto_da_alloc=%u/noauto_da_alloc [ext4]
It's rare. So much that I don't believe that fs_param_v_optional has any
reason to exist. Let's split those entries and be done with that.
Hmm... Deciding whether we have an argument-bearing or no-argument case
is somewhat inconvenient for fsconfig-generated calls - check for
NULL param->string is, strictly speaking, in nasal daemon territory
for types other than flag and string... OK, sold - let's check for
fs_value_is_flag. So I'm combining your patch with #9/12 (to avoid bisect
hazard) + correction for rbd. And putting that in the very beginning of
fs_parser reorg series, with elimination of fs_param_v_optional closer
to the end.
