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Re: [Qemu-devel] [PATCH v2 0/4] monitor: do not rely on O_NONBLOCK for p
From: |
mdroth |
Subject: |
Re: [Qemu-devel] [PATCH v2 0/4] monitor: do not rely on O_NONBLOCK for passed file descriptors |
Date: |
Wed, 3 Apr 2013 10:05:40 -0500 |
User-agent: |
Mutt/1.5.21 (2010-09-15) |
On Wed, Mar 27, 2013 at 09:17:30AM -0400, Luiz Capitulino wrote:
> On Wed, 27 Mar 2013 10:10:42 +0100
> Stefan Hajnoczi <address@hidden> wrote:
>
> > There are several places where QEMU accidentally relies on the O_NONBLOCK
> > state
> > of passed file descriptors. Exposing O_NONBLOCK state makes it part of the
> > QMP
> > API whenever getfd or fdset_add_fd are used!
> >
> > Whether or not QEMU will use O_NONBLOCK is an implementation detail and
> > should
> > be hidden from QMP clients.
> >
> > This patch series addresses this in 3 steps:
>
> Nice series:
>
> Applied to the qmp branch, thanks.
Hi Luiz,
Eric/mjt have noted that this series fixes a number of issues in 1.4.0
and have requested it for 1.4.1
http://thread.gmane.org/gmane.comp.emulators.qemu/203851
The cut-off for 1.4.1 is Tuesday. Do you plan to send a pull for these soon?
>
> >
> > 1. Fix callers of monitor_handle_fd_param(), monitor_fdset_get_fd(), and
> > monitor_get_fd() that depend on O_NONBLOCK being set. Luckily there are
> > only two instances and they are fixed in Patches 1 & 2.
> >
> > 2. Rename socket_set_nonblock() to qemu_set_nonblock() just like
> > qemu_set_cloexec(). This makes code cleaner when working with arbitrary
> > file descriptors that may not be sockets. See Patch 3.
> >
> > 3. Clear O_NONBLOCK when a chardev receives file descriptors. From now on
> > QEMU
> > can assume that passed file descriptors are in blocking mode. Simply use
> > qemu_set_nonblock(fd) if you want to enable O_NONBLOCK. See Patch 4.
> >
> > This fixes live migration with recent libvirt. Libvirt checks if QEMU
> > supports
> > file descriptor passing and, if yes, hands QEMU a socket with O_NONBLOCK
> > set.
> > The migrate fd:<foo> code assumes the socket is in blocking mode. The
> > result
> > is a corrupted migration stream. For more info on this bug, see:
> >
> > https://bugzilla.redhat.com/show_bug.cgi?id=923124
> >
> > Note that Michal Privoznik <address@hidden> also sent a libvirt patch so
> > that old QEMUs work with new libvirts:
> >
> > https://www.redhat.com/archives/libvir-list/2013-March/msg01486.html
> >
> > My patch series fixes the QMP API and allows old libvirts to work again with
> > new QEMUs.
> >
> > v2:
> > * Rename socket_set_nonblock() in Patch 1 to avoid code churn [eblake]
> > * Avoid qemu_set_block(-1) calls that clobber errno [quintela]
> >
> > Stefan Hajnoczi (4):
> > oslib-posix: rename socket_set_nonblock() to qemu_set_nonblock()
> > net: ensure "socket" backend uses non-blocking fds
> > qemu-socket: set passed fd non-blocking in socket_connect()
> > chardev: clear O_NONBLOCK on SCM_RIGHTS file descriptors
> >
> > block/nbd.c | 2 +-
> > block/sheepdog.c | 2 +-
> > include/qemu/sockets.h | 4 ++--
> > migration.c | 2 +-
> > nbd.c | 8 ++++----
> > net/socket.c | 13 +++++++++----
> > qemu-char.c | 11 +++++++----
> > savevm.c | 2 +-
> > slirp/misc.c | 2 +-
> > slirp/tcp_subr.c | 4 ++--
> > ui/vnc.c | 2 +-
> > util/oslib-posix.c | 4 ++--
> > util/oslib-win32.c | 4 ++--
> > util/qemu-sockets.c | 5 +++--
> > 14 files changed, 37 insertions(+), 28 deletions(-)
> >
>
>
- Re: [Qemu-devel] [PATCH v2 0/4] monitor: do not rely on O_NONBLOCK for passed file descriptors,
mdroth <=