Re: [PATCH] exfat: doc: add documentation

[Namjae Jeon]

On Mon, Aug 31, 2026 at 11:49 PM Zhan Xusheng <zhanxusheng1024@xxxxxxxxx> wrote:
>
> The option list and the defaults match fs/exfat/, including the allow_utime
> derivation and the time_offset range.  Three things the table leaves out or
> implies.
>
> Most of the options cannot be changed on remount.  exfat_reconfigure()
> fails with -EINVAL if iocharset, keep_last_dots, sys_tz, time_offset, uid,
> gid, fmask, dmask or allow_utime differ from the current values
> (super.c:789), leaving only errors, discard and zero_size_dir.  Nothing is
> logged on that path, so "mount -o remount,uid=1000" returns a bare EINVAL.
> The reason sits in the code right above the test: the old values are cached
> in inodes and dentries.
>
> umask= sets both masks, and the options take effect in the order they are
> written.  Opt_umask assigns fs_fmask and fs_dmask (super.c:289), so
> "-o umask=0022,dmask=0077" ends up with dmask 0077, while
> "-o dmask=0077,umask=0022" silently puts dmask back to 0022.  The dmask=
> and fmask= entries also do not give their default, which is the same
> current umask that umask= defaults to.
>
> utf8 is ignored rather than an old spelling of iocharset=utf8.  It shares a
> fallthrough with debug, namecase= and codepage= (super.c:331), so
> "mount -o utf8" selects nothing.  exfat_show_options() prints
> iocharset=utf8 only when opts->utf8 is set (super.c:132), and nothing sets
> that but iocharset=utf8.  Listing utf8 apart from the group described as
> "Deprecated and ignored" reads as if it still has an effect.
I will update them on the v2 version.
Thanks for the review!