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 7031BC4345F for ; Mon, 29 Apr 2024 18:48:35 +0000 (UTC) Received: from localhost ([::1] helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1s1W2a-00065m-F1; Mon, 29 Apr 2024 14:47:52 -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 1s1W2T-0005xU-LP for qemu-devel@nongnu.org; Mon, 29 Apr 2024 14:47:50 -0400 Received: from smtp-out1.suse.de ([195.135.223.130]) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_128_GCM_SHA256:128) (Exim 4.90_1) (envelope-from ) id 1s1W2R-0000Li-U1 for qemu-devel@nongnu.org; Mon, 29 Apr 2024 14:47:45 -0400 Received: from imap1.dmz-prg2.suse.org (imap1.dmz-prg2.suse.org [10.150.64.97]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (4096 bits) server-digest SHA256) (No client certificate requested) by smtp-out1.suse.de (Postfix) with ESMTPS id 356E433A22; Mon, 29 Apr 2024 18:47:42 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=suse.de; s=susede2_rsa; t=1714416462; h=from:from:reply-to:date:date:message-id:message-id:to:to:cc:cc: mime-version:mime-version:content-type:content-type: in-reply-to:in-reply-to:references:references; bh=r6QVWdAILr0Y4hV5RI0vcJpGAoRbDZ3D1pqMfejytSo=; b=mU5qimqSKGpD9i+wGSzlZgimZnL6+anER1Tx03kLoCfDCGJxo8HvaxdOyKcaDxH4Ws1nnJ SqGXAR81fGVq11SyMnZmPyOlEIYRqySIx3xEJDdZXHzZhvGHbfO+BJ3pANMCmgQifHatBH 8rBtpwYK8gPDJjpT6UwCbXsO39+4izo= DKIM-Signature: v=1; a=ed25519-sha256; c=relaxed/relaxed; d=suse.de; s=susede2_ed25519; t=1714416462; h=from:from:reply-to:date:date:message-id:message-id:to:to:cc:cc: mime-version:mime-version:content-type:content-type: in-reply-to:in-reply-to:references:references; bh=r6QVWdAILr0Y4hV5RI0vcJpGAoRbDZ3D1pqMfejytSo=; b=cDwj+I5HZ6rvm8T404Wui6/2w5CXw8+xaqsqKZB4SJOWAUw39T4lQOMLfkUzPbujlFL6dQ +cfXzk9kug2N2yAg== Authentication-Results: smtp-out1.suse.de; none DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=suse.de; s=susede2_rsa; t=1714416462; h=from:from:reply-to:date:date:message-id:message-id:to:to:cc:cc: mime-version:mime-version:content-type:content-type: in-reply-to:in-reply-to:references:references; bh=r6QVWdAILr0Y4hV5RI0vcJpGAoRbDZ3D1pqMfejytSo=; b=mU5qimqSKGpD9i+wGSzlZgimZnL6+anER1Tx03kLoCfDCGJxo8HvaxdOyKcaDxH4Ws1nnJ SqGXAR81fGVq11SyMnZmPyOlEIYRqySIx3xEJDdZXHzZhvGHbfO+BJ3pANMCmgQifHatBH 8rBtpwYK8gPDJjpT6UwCbXsO39+4izo= DKIM-Signature: v=1; a=ed25519-sha256; c=relaxed/relaxed; d=suse.de; s=susede2_ed25519; t=1714416462; h=from:from:reply-to:date:date:message-id:message-id:to:to:cc:cc: mime-version:mime-version:content-type:content-type: in-reply-to:in-reply-to:references:references; bh=r6QVWdAILr0Y4hV5RI0vcJpGAoRbDZ3D1pqMfejytSo=; b=cDwj+I5HZ6rvm8T404Wui6/2w5CXw8+xaqsqKZB4SJOWAUw39T4lQOMLfkUzPbujlFL6dQ +cfXzk9kug2N2yAg== Received: from imap1.dmz-prg2.suse.org (localhost [127.0.0.1]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (4096 bits) server-digest SHA256) (No client certificate requested) by imap1.dmz-prg2.suse.org (Postfix) with ESMTPS id B2413138A7; Mon, 29 Apr 2024 18:47:41 +0000 (UTC) Received: from dovecot-director2.suse.de ([2a07:de40:b281:106:10:150:64:167]) by imap1.dmz-prg2.suse.org with ESMTPSA id FKsXHk3rL2YUXwAAD6G6ig (envelope-from ); Mon, 29 Apr 2024 18:47:41 +0000 From: Fabiano Rosas To: Peter Xu Cc: qemu-devel@nongnu.org, =?utf-8?Q?Daniel_P_=2E_Berrang=C3=A9?= , devel@lists.libvirt.org Subject: Re: [PATCH v2 6/6] migration: Deprecate fd: for file migration In-Reply-To: References: <20240426131408.25410-1-farosas@suse.de> <20240426131408.25410-7-farosas@suse.de> Date: Mon, 29 Apr 2024 15:47:39 -0300 Message-ID: <87zftcdn04.fsf@suse.de> MIME-Version: 1.0 Content-Type: text/plain X-Spamd-Result: default: False [-4.30 / 50.00]; BAYES_HAM(-3.00)[100.00%]; NEURAL_HAM_LONG(-1.00)[-1.000]; NEURAL_HAM_SHORT(-0.20)[-1.000]; MIME_GOOD(-0.10)[text/plain]; ARC_NA(0.00)[]; RCVD_VIA_SMTP_AUTH(0.00)[]; MISSING_XM_UA(0.00)[]; MIME_TRACE(0.00)[0:+]; MID_RHS_MATCH_FROM(0.00)[]; RCVD_TLS_ALL(0.00)[]; DKIM_SIGNED(0.00)[suse.de:s=susede2_rsa,suse.de:s=susede2_ed25519]; FUZZY_BLOCKED(0.00)[rspamd.com]; FROM_HAS_DN(0.00)[]; TO_DN_SOME(0.00)[]; FROM_EQ_ENVFROM(0.00)[]; TO_MATCH_ENVRCPT_ALL(0.00)[]; RCVD_COUNT_TWO(0.00)[2]; RCPT_COUNT_THREE(0.00)[4] Received-SPF: pass client-ip=195.135.223.130; envelope-from=farosas@suse.de; helo=smtp-out1.suse.de X-Spam_score_int: -43 X-Spam_score: -4.4 X-Spam_bar: ---- X-Spam_report: (-4.4 / 5.0 requ) BAYES_00=-1.9, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, DKIM_VALID_EF=-0.1, RCVD_IN_DNSWL_MED=-2.3, 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: , Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Peter Xu writes: > On Fri, Apr 26, 2024 at 10:14:08AM -0300, Fabiano Rosas wrote: >> The fd: URI can currently trigger two different types of migration, a >> TCP migration using sockets and a file migration using a plain >> file. This is in conflict with the recently introduced (8.2) QMP >> migrate API that takes structured data as JSON-like format. We cannot >> keep the same backend for both types of migration because with the new >> API the code is more tightly coupled to the type of transport. This >> means a TCP migration must use the 'socket' transport and a file >> migration must use the 'file' transport. >> >> If we keep allowing fd: when using a file, this creates an issue when >> the user converts the old-style (fd:) to the new style ("transport": >> "socket") invocation because the file descriptor in question has >> previously been allowed to be either a plain file or a socket. >> >> To avoid creating too much confusion, we can simply deprecate the fd: >> + file usage, which is thought to be rarely used currently and instead >> establish a 1:1 correspondence between fd: URI and socket transport, >> and file: URI and file transport. >> >> Signed-off-by: Fabiano Rosas >> --- >> docs/about/deprecated.rst | 14 ++++++++++++++ >> 1 file changed, 14 insertions(+) >> >> diff --git a/docs/about/deprecated.rst b/docs/about/deprecated.rst >> index 0fb5c82640..813f7996fe 100644 >> --- a/docs/about/deprecated.rst >> +++ b/docs/about/deprecated.rst >> @@ -464,3 +464,17 @@ both, older and future versions of QEMU. >> The ``blacklist`` config file option has been renamed to ``block-rpcs`` >> (to be in sync with the renaming of the corresponding command line >> option). >> + >> +Migration >> +--------- >> + >> +``fd:`` URI when used for file migration (since 9.1) >> +'''''''''''''''''''''''''''''''''''''''''''''''''''' >> + >> +The ``fd:`` URI can currently provide a file descriptor that >> +references either a socket or a plain file. These are two different >> +types of migration. In order to reduce ambiguity, the ``fd:`` URI >> +usage of providing a file descriptor to a plain file has been >> +deprecated in favor of explicitly using the ``file:`` URI with the >> +file descriptor being passed as an ``fdset``. Refer to the ``add-fd`` >> +command documentation for details on the ``fdset`` usage. > > Wanna do some warn_report() when detected non-socket fds alongside? Looks > like we previously do this for all deprecations. Yes, good point. > > What's the plan when it's support removed? I'm imaginging that we sanity > check fstat() + S_ISSOCK on the fd and fail otherwise? In that case we can > have the code there, dump warn_report(), then switch to failing qmp migrate > (and incoming side) later on? Something along those lines. We currently use fd_is_socket(): bool fd_is_socket(int fd) { int optval; socklen_t optlen = sizeof(optval); return !getsockopt(fd, SOL_SOCKET, SO_TYPE, &optval, &optlen); } I'm thinking of this in fd_start_outgoing_migation(): if (!fd_is_socket(fd)) { warn_report("fd: migration to a file is deprecated." " Use file: instead."); }