From: "Theodore Y. Ts'o" <tytso@mit.edu>
To: Peter Maydell <peter.maydell@linaro.org>,
Andreas Dilger <adilger@dilger.ca>,
Florian Weimer <fw@deneb.enyo.de>,
linux-fsdevel <linux-fsdevel@vger.kernel.org>,
Linux API <linux-api@vger.kernel.org>,
Ext4 Developers List <linux-ext4@vger.kernel.org>,
<lucho@ionkov.net>, <libc-alpha@sourceware.org>,
Arnd Bergmann <arnd@arndb.de>, <ericvh@gmail.com>,
<hpa@zytor.com>,
lkml - Kernel Mailing List <linux-kernel@vger.kernel.org>,
QEMU Developers <qemu-devel@nongnu.org>, <rminnich@sandia.gov>,
<v9fs-developer@lists.sourceforge.net>
Subject: Re: [Qemu-devel] d_off field in struct dirent and 32-on-64 emulation
Date: Fri, 28 Dec 2018 22:14:16 -0500 [thread overview]
Message-ID: <20181229031416.GH5864@mit.edu> (raw)
In-Reply-To: <20181229023721.GA9291@nautica>
On Sat, Dec 29, 2018 at 03:37:21AM +0100, Dominique Martinet wrote:
> > Are there going to be cases where a process or a thread will sometimes
> > want the 64-bit interface, and sometimes want the 32-bit interface?
> > Or is it always going to be one or the other? I wonder if we could
> > simply add a new flag to the process personality(2) flags.
>
> That would likely work for qemu user, but the qemu system+9p case is
> going to be more painful..
> More precisely, the 9p protocol does not plan for anything other than
> 64bit offset so if the vfs needs to hand out a 32bit offset we'll need
> to make a correspondance table between the 32bit offsets we hand off and
> the 64bit ones to use; unless some flag can be passed at lopen to tell
> the server to always hand out 32bit offsets for this directory... And if
> we do that then 9p servers will need a way to use both APIs in parallel
> for both types of directories.
How about if we add a fcntl(2) mediated flag, which is tied to a
struct file? Would that be more or less painful for 9p and qemu
system+9p?
- Ted
next prev parent reply other threads:[~2018-12-29 4:18 UTC|newest]
Thread overview: 25+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-12-27 17:18 d_off field in struct dirent and 32-on-64 emulation Florian Weimer
2018-12-27 17:41 ` [Qemu-devel] " Peter Maydell
2018-12-28 0:23 ` Andreas Dilger
2018-12-28 11:18 ` Peter Maydell
2018-12-28 23:16 ` Andreas Dilger
2018-12-29 0:12 ` Peter Maydell
2018-12-29 1:54 ` Matthew Wilcox
2018-12-29 16:49 ` Andy Lutomirski
2018-12-30 13:59 ` Peter Maydell
2018-12-29 2:11 ` Theodore Y. Ts'o
2018-12-29 2:37 ` Dominique Martinet
2018-12-29 3:14 ` Theodore Y. Ts'o [this message]
2018-12-29 4:04 ` [V9fs-developer] " Dominique Martinet
[not found] ` <C65D3222-723F-4C0B-AF02-38488C302E84@amacapital.net>
2018-12-27 17:56 ` Florian Weimer
2018-12-27 17:58 ` Adhemerval Zanella
2018-12-27 18:09 ` Florian Weimer
2018-12-28 11:53 ` Adhemerval Zanella
2018-12-28 11:56 ` Florian Weimer
2018-12-28 12:01 ` Florian Weimer
2018-12-28 12:21 ` Adhemerval Zanella
2018-12-31 17:03 ` Joseph Myers
2019-01-02 13:16 ` Adhemerval Zanella
2018-12-28 2:23 ` Dmitry V. Levin
2018-12-28 7:38 ` Florian Weimer
2018-12-28 15:26 ` Andy Lutomirski
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