From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from lists.gnu.org (lists.gnu.org [209.51.188.17]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id B7FEDC25B6D for ; Wed, 25 Oct 2023 15:27:01 +0000 (UTC) Received: from localhost ([::1] helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1qvfmH-0002kq-UZ; Wed, 25 Oct 2023 11:26:37 -0400 Received: from eggs.gnu.org ([2001:470:142:3::10]) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1qvfmG-0002kf-SG for qemu-devel@nongnu.org; Wed, 25 Oct 2023 11:26:36 -0400 Received: from us-smtp-delivery-124.mimecast.com ([170.10.133.124]) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1qvfmF-0005oG-3I for qemu-devel@nongnu.org; Wed, 25 Oct 2023 11:26:36 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1698247594; h=from:from:reply-to:reply-to:subject:subject:date:date: message-id:message-id:to:to:cc:cc:mime-version:mime-version: content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=iCxRy1OhwUKmBWEHf2NAxtHjYfVsVlxHt7uukogM58Q=; b=SUPdrpLtqKsdGGLN1U+gzb39R7sLX3ewFUC3vSs3C/OY1g6O+shNBX93gpKDuosc2ctWSf JWkvFnsn5qWX+RWXrnJpW77GCAEk7e/EWR62kErkcXDqbLSjSxJbK2fOcvQCeSZJ36nJFZ bwAX9qouA9KV8aPAgUL2R2yofLgltMI= Received: from mimecast-mx02.redhat.com (mimecast-mx02.redhat.com [66.187.233.88]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.3, cipher=TLS_AES_256_GCM_SHA384) id us-mta-398-5iDa6QSfPp-q6bPpWXdjBw-1; Wed, 25 Oct 2023 11:26:29 -0400 X-MC-Unique: 5iDa6QSfPp-q6bPpWXdjBw-1 Received: from smtp.corp.redhat.com (int-mx10.intmail.prod.int.rdu2.redhat.com [10.11.54.10]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (2048 bits) server-digest SHA256) (No client certificate requested) by mimecast-mx02.redhat.com (Postfix) with ESMTPS id 4208C811E7E; Wed, 25 Oct 2023 15:26:29 +0000 (UTC) Received: from redhat.com (unknown [10.42.28.154]) by smtp.corp.redhat.com (Postfix) with ESMTPS id D2ADB492BFA; Wed, 25 Oct 2023 15:26:27 +0000 (UTC) Date: Wed, 25 Oct 2023 16:26:25 +0100 From: Daniel =?utf-8?B?UC4gQmVycmFuZ8Op?= To: Fabiano Rosas Cc: qemu-devel@nongnu.org, armbru@redhat.com, Juan Quintela , Peter Xu , Leonardo Bras , Claudio Fontana Subject: Re: [PATCH v2 19/29] migration/multifd: Add outgoing QIOChannelFile support Message-ID: References: <20231023203608.26370-1-farosas@suse.de> <20231023203608.26370-20-farosas@suse.de> <87o7gmeqp5.fsf@suse.de> <877cnaeohv.fsf@suse.de> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: <877cnaeohv.fsf@suse.de> User-Agent: Mutt/2.2.9 (2022-11-12) X-Scanned-By: MIMEDefang 3.4.1 on 10.11.54.10 Received-SPF: pass client-ip=170.10.133.124; envelope-from=berrange@redhat.com; helo=us-smtp-delivery-124.mimecast.com X-Spam_score_int: -20 X-Spam_score: -2.1 X-Spam_bar: -- X-Spam_report: (-2.1 / 5.0 requ) BAYES_00=-1.9, DKIMWL_WL_HIGH=-0.001, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, DKIM_VALID_EF=-0.1, RCVD_IN_DNSWL_NONE=-0.0001, RCVD_IN_MSPIKE_H3=0.001, RCVD_IN_MSPIKE_WL=0.001, SPF_HELO_NONE=0.001, SPF_PASS=-0.001 autolearn=ham autolearn_force=no X-Spam_action: no action X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Reply-To: Daniel =?utf-8?B?UC4gQmVycmFuZ8Op?= Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org On Wed, Oct 25, 2023 at 12:00:12PM -0300, Fabiano Rosas wrote: > Daniel P. Berrangé writes: > > > On Wed, Oct 25, 2023 at 11:12:38AM -0300, Fabiano Rosas wrote: > >> Daniel P. Berrangé writes: > >> > >> > On Mon, Oct 23, 2023 at 05:35:58PM -0300, Fabiano Rosas wrote: > >> >> Allow multifd to open file-backed channels. This will be used when > >> >> enabling the fixed-ram migration stream format which expects a > >> >> seekable transport. > >> >> > >> >> The QIOChannel read and write methods will use the preadv/pwritev > >> >> versions which don't update the file offset at each call so we can > >> >> reuse the fd without re-opening for every channel. > >> >> > >> >> Note that this is just setup code and multifd cannot yet make use of > >> >> the file channels. > >> >> > >> >> Signed-off-by: Fabiano Rosas > >> >> --- > >> >> migration/file.c | 64 +++++++++++++++++++++++++++++++++++++++++-- > >> >> migration/file.h | 10 +++++-- > >> >> migration/migration.c | 2 +- > >> >> migration/multifd.c | 14 ++++++++-- > >> >> migration/options.c | 7 +++++ > >> >> migration/options.h | 1 + > >> >> 6 files changed, 90 insertions(+), 8 deletions(-) > >> >> > >> >> diff --git a/migration/file.c b/migration/file.c > >> >> index cf5b1bf365..93b9b7bf5d 100644 > >> >> --- a/migration/file.c > >> >> +++ b/migration/file.c > >> >> @@ -17,6 +17,12 @@ > >> > > >> >> +void file_send_channel_create(QIOTaskFunc f, void *data) > >> >> +{ > >> >> + QIOChannelFile *ioc; > >> >> + QIOTask *task; > >> >> + Error *errp = NULL; > >> >> + > >> >> + ioc = qio_channel_file_new_path(outgoing_args.fname, > >> >> + outgoing_args.flags, > >> >> + outgoing_args.mode, &errp); > >> >> + if (!ioc) { > >> >> + file_migration_cancel(errp); > >> >> + return; > >> >> + } > >> >> + > >> >> + task = qio_task_new(OBJECT(ioc), f, (gpointer)data, NULL); > >> >> + qio_task_run_in_thread(task, qio_channel_file_connect_worker, > >> >> + (gpointer)data, NULL, NULL); > >> >> +} > >> >> + > >> >> void file_start_outgoing_migration(MigrationState *s, const char *filespec, > >> >> Error **errp) > >> >> { > >> >> - g_autofree char *filename = g_strdup(filespec); > >> >> g_autoptr(QIOChannelFile) fioc = NULL; > >> >> + g_autofree char *filename = g_strdup(filespec); > >> >> uint64_t offset = 0; > >> >> QIOChannel *ioc; > >> >> + int flags = O_CREAT | O_TRUNC | O_WRONLY; > >> >> + mode_t mode = 0660; > >> >> > >> >> trace_migration_file_outgoing(filename); > >> >> > >> >> @@ -50,12 +105,15 @@ void file_start_outgoing_migration(MigrationState *s, const char *filespec, > >> >> return; > >> >> } > >> >> > >> >> - fioc = qio_channel_file_new_path(filename, O_CREAT | O_WRONLY | O_TRUNC, > >> >> - 0600, errp); > >> > >> By the way, we're experimenting with add-fd to flesh out the interface > >> with libvirt and I see that the flags here can conflict with the flags > >> set on the fd passed through `virsh --pass-fd ...` due to this at > >> monitor_fdset_dup_fd_add(): > >> > >> if ((flags & O_ACCMODE) == (mon_fd_flags & O_ACCMODE)) { > >> fd = mon_fdset_fd->fd; > >> break; > >> } > >> > >> We're requiring the O_RDONLY, O_WRONLY, O_RDWR flags defined here to > >> match the fdset passed into QEMU. Should we just sync the code of the > >> two projects to use the same flags? That feels a little clumsy to me. > > > > Is there a reason for libvirt to have set O_RDONLY for a file used > > for outgoing migration ? I can't recall off-hand. > > > > The flags need to match exactly, so either libvirt or QEMU could in the > future decide to use O_RDWR. Then we'd have a compatibility problem when > passing the fds around. The "safe" option would be to always open O_RDWR, even if it is technically redundant for our current needs. With regards, Daniel -- |: https://berrange.com -o- https://www.flickr.com/photos/dberrange :| |: https://libvirt.org -o- https://fstop138.berrange.com :| |: https://entangle-photo.org -o- https://www.instagram.com/dberrange :|