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From:   Miklos Szeredi <miklos@szeredi.hu>
Date:   Wed, 24 Apr 2019 14:17:27 +0200
Message-ID: <CAJfpegsiWuykUsfg=sO8sKo5h86U65q10=e=wYKXTQEHW8DFkw@mail.gmail.com>
Subject: Re: [RESEND4, PATCH 1/2] fuse: retrieve: cap requested size to
 negotiated max_write
To:     Kirill Smelkov <kirr@nexedi.com>
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>
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Sender: linux-kernel-owner@vger.kernel.org
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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_conn *fc, struct inode *inode,
>                 unsigned int offset;
>                 size_t total_len = 0;
>                 unsigned int num_pages;
>
>                 offset = outarg->offset & ~PAGE_MASK;
>                 file_size = i_size_read(inode);
>
>         -       num = outarg->size;
>         +       num = min(outarg->size, fc->max_write);
>                 if (outarg->offset > file_size)
>                         num = 0;
>                 else if (outarg->offset + num > file_size)
>                         num = file_size - outarg->offset;               <-- THIS
>
>                 num_pages = (num + offset + PAGE_SIZE - 1) >> PAGE_SHIFT;
>                 num_pages = min(num_pages, fc->max_pages);
>
> and then in this case (offset + num > file_size) num overwrite
>
>         num = file_size - offset
>
> can make num only smaller, right? And then the patch is not wrong because there
> is no other num overwriting in this function except when num is being further
> decremented in loop that prepares pages to retrieve.

You're right, of course.


> > 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.

Thanks,
Miklos