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From:   Kirill Smelkov <kirr@nexedi.com>
Subject: Re: [RESEND4, PATCH 1/2] fuse: retrieve: cap requested size to negotiated max_write
To:     Miklos Szeredi <miklos@szeredi.hu>
Cc:     Miklos Szeredi <mszeredi@redhat.com>,
        Han-Wen Nienhuys <hanwen@google.com>,
        Jakob Unterwurzacher <jakobunt@gmail.com>,
        Kirill Tkhai <ktkhai@virtuozzo.com>,
        Andrew Morton <akpm@linux-foundation.org>,
        <linux-fsdevel@vger.kernel.org>, <linux-kernel@vger.kernel.org>,
        fuse-devel <fuse-devel@lists.sourceforge.net>,
        stable <stable@vger.kernel.org>
Message-Id: <20190424123107.GA32024@deco.navytux.spb.ru>
References: <cover.1553680185.git.kirr@nexedi.com> <12f7d0d98555ee0d174d04bb47644f65c07f035a.1553680185.git.kirr@nexedi.com> <CAJfpegv0NvcsD9gh3aN+ngzsLqbNWUc73ZPN1qHox_14eN9Pqg@mail.gmail.com> <20190424115620.GA2723@deco.navytux.spb.ru> <CAJfpegsiWuykUsfg=sO8sKo5h86U65q10=e=wYKXTQEHW8DFkw@mail.gmail.com>
In-Reply-To: <CAJfpegsiWuykUsfg=sO8sKo5h86U65q10=e=wYKXTQEHW8DFkw@mail.gmail.com>
Date:   Wed, 24 Apr 2019 12:31:14 +0000
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Sender: linux-kernel-owner@vger.kernel.org
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On Wed, Apr 24, 2019 at 02:17:27PM +0200, Miklos Szeredi wrote:
> On Wed, Apr 24, 2019 at 1:56 PM Kirill Smelkov <kirr@nexedi.com> wrote:
> 
> > I assume you are meaning this:
> >
> >         --- a/fs/fuse/dev.c
> >         +++ b/fs/fuse/dev.c
> >         @@ -1745,15 +1745,15 @@ static int fuse_retrieve(struct fuse_co=
nn *fc, struct inode *inode,
> >                 unsigned int offset;
> >                 size_t total_len =3D 0;
> >                 unsigned int num_pages;
> >
> >                 offset =3D outarg->offset & ~PAGE_MASK;
> >                 file_size =3D i_size_read(inode);
> >
> >         -       num =3D outarg->size;
> >         +       num =3D min(outarg->size, fc->max_write);
> >                 if (outarg->offset > file_size)
> >                         num =3D 0;
> >                 else if (outarg->offset + num > file_size)
> >                         num =3D file_size - outarg->offset;            =
   <-- THIS
> >
> >                 num_pages =3D (num + offset + PAGE_SIZE - 1) >> PAGE_SH=
IFT;
> >                 num_pages =3D min(num_pages, fc->max_pages);
> >
> > and then in this case (offset + num > file_size) num overwrite
> >
> >         num =3D file_size - offset
> >
> > can make num only smaller, right? And then the patch is not wrong becau=
se there
> > is no other num overwriting in this function except when num is being f=
urther
> > decremented in loop that prepares pages to retrieve.
> 
> You're right, of course.

Thanks. Does it mean that the patch is ok? Do I need to rework
something?


> > > Also the patch is whitespace damaged.
> >
> > I've tried to do the following in my mutt on "RESEND4, PATCH 1/2"
> > message:
> >
> >         |(cd ~/src/linux/linux && git am -)
> >
> > and the patch applied successfully. So could you please clarify what
> > "whitespace damaged" means?
> 
> Hmm, apparently this (and only this) message is "quoted-printable"
> encoded.  git-am seems to handle it fine, but my script doesn't.
> Anyway, I'll do it manually.

I see. Probably it is not "quoted-printable" as

=09Content-Type: text/plain; charset=3Dutf-8
=09Content-Transfer-Encoding: 8bit

suggests and it is maybe due to UTF-8 characters (I used "=C2=B7" several
times in patch description). Anyway if it helps you can pull the patch
from here

=09https://lab.nexedi.com/kirr/linux.git=09y/fuse-retrieve-cap-max_write
=09
and then cherry-pick it (git cherry-pick fd482f96537a) to where needed.

Thanks again for feedback,

Kirill