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Date:   Fri, 4 Jun 2021 10:33:03 +0200
From:   Greg KH <greg@kroah.com>
To:     David Laight <David.Laight@aculab.com>
Cc:     'Jaegeuk Kim' <jaegeuk@kernel.org>,
        Eric Biggers <ebiggers@kernel.org>,
        Daniel Rosenberg <drosen@google.com>,
        Chao Yu <chao@kernel.org>,
        "linux-f2fs-devel@lists.sourceforge.net" 
        <linux-f2fs-devel@lists.sourceforge.net>,
        "linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
        "linux-fsdevel@vger.kernel.org" <linux-fsdevel@vger.kernel.org>,
        Gabriel Krisman Bertazi <krisman@collabora.com>,
        "kernel-team@android.com" <kernel-team@android.com>,
        "stable@vger.kernel.org" <stable@vger.kernel.org>
Subject: Re: [PATCH v2 2/2] f2fs: Advertise encrypted casefolding in sysfs
Message-ID: <YLnlPxfCVJD+p6/a@kroah.com>
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On Fri, Jun 04, 2021 at 08:27:32AM +0000, David Laight wrote:
> From: Jaegeuk Kim
> > Sent: 04 June 2021 05:45
> ...
> > > > @@ -161,6 +161,9 @@ static ssize_t features_show(struct f2fs_attr *a,
> > > >  	if (f2fs_sb_has_compression(sbi))
> > > >  		len += scnprintf(buf + len, PAGE_SIZE - len, "%s%s",
> > > >  				len ? ", " : "", "compression");
> > > > +	if (f2fs_sb_has_casefold(sbi) && f2fs_sb_has_encrypt(sbi))
> > > > +		len += scnprintf(buf + len, PAGE_SIZE - len, "%s%s",
> > > > +				len ? ", " : "", "encrypted_casefold");
> > > >  	len += scnprintf(buf + len, PAGE_SIZE - len, "%s%s",
> > > >  				len ? ", " : "", "pin_file");
> > > >  	len += scnprintf(buf + len, PAGE_SIZE - len, "\n");
> 
> Looking at that pattern, why don't you just append "tag, "
> each time and then replace the final ", " with "\n" at the end.

Again PLEASE NO!

This is not how sysfs is supposed to work and do not perpetuate this
mess in any way.

greg k-h