linux-ext4 - Re: [PATCH v9 2/9] ext4: add fast_commit feature and handling for extended mount options

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Date:   Mon, 12 Oct 2020 17:27:44 -0700
From:   harshad shirwadkar <harshadshirwadkar@...il.com>
To:     "Theodore Y. Ts'o" <tytso@....edu>
Cc:     Ext4 Developers List <linux-ext4@...r.kernel.org>
Subject: Re: [PATCH v9 2/9] ext4: add fast_commit feature and handling for
 extended mount options

On Fri, Oct 9, 2020 at 10:58 AM Theodore Y. Ts'o <tytso@....edu> wrote:
>
> On Fri, Sep 18, 2020 at 05:54:44PM -0700, Harshad Shirwadkar wrote:
> > We are running out of mount option bits. Add handling for using
> > s_mount_opt2. Add ext4 and jbd2 fast commit feature flag and also add
> > ability to turn on / off the fast commit feature in Ext4.
>
> Shouldn't that read "...ability to turn off the fast commit feature via a
> mount option"?
>
> > @@ -2207,10 +2211,17 @@ static int handle_mount_opt(struct super_block *sb, char *opt, int token,
> >                       WARN_ON(1);
> >                       return -1;
> >               }
> > -             if (arg != 0)
> > -                     sbi->s_mount_opt |= m->mount_opt;
> > -             else
> > -                     sbi->s_mount_opt &= ~m->mount_opt;
> > +             if (m->flags & MOPT_2) {
> > +                     if (arg != 0)
> > +                             sbi->s_mount_opt2 |= m->mount_opt;
> > +                     else
> > +                             sbi->s_mount_opt2 &= ~m->mount_opt;
> > +             } else {
> > +                     if (arg != 0)
> > +                             sbi->s_mount_opt |= m->mount_opt;
> > +                     else
> > +                             sbi->s_mount_opt &= ~m->mount_opt;
> > +             }
> >       }
> >       return 1;
> >  }
>
>
> This requires a matching change in _ext4_show_options(), so that the
> MOPT_2 options are properly displayed in /proc/mounts.
Thanks for pointing that out, I'll add this in V10.

Thanks,
Harshad
>
>                                                 - Ted