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(unknown [2a02:6bf:8080:b48::1:39]) by mail-nwsmtp-smtp-corp-main-66.iva.yp-c.yandex.net (smtpcorp/Yandex) with ESMTPSA id EVQIl30GrmI0-lbSdqVZf; Wed, 10 Sep 2025 22:31:15 +0300 X-Yandex-Fwd: 1 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=yandex-team.ru; s=default; t=1757532675; bh=6zk2HlwQVu6MiqppbHH1LwEAltQId5nu3DmhF1Zfbf4=; h=Cc:Message-ID:References:Date:In-Reply-To:Subject:To:From; b=VJEeJdxmorXMg6fq2DRqPC1CfND+3H5EEiK7FYB6l/GSjfK51RAIeKje8t5fPLux7 3fablURFXGN2LOGQQakIxGd9/2Y6Cw3T4js8efVz9aCIKubniuFThUFQOIYsJWNYRA rQ2dcfmvLu9SOPfTBfw5QWWXuyTggM2HohtKjrk4= Authentication-Results: mail-nwsmtp-smtp-corp-main-66.iva.yp-c.yandex.net; dkim=pass header.i=@yandex-team.ru From: Vladimir Sementsov-Ogievskiy To: berrange@redhat.com Cc: peterx@redhat.com, farosas@suse.de, steven.sistare@oracle.com, vsementsov@yandex-team.ru, qemu-devel@nongnu.org Subject: [PATCH v4 1/2] migration/qemu-file: don't make incoming fds blocking again Date: Wed, 10 Sep 2025 22:31:11 +0300 Message-ID: <20250910193112.1220763-2-vsementsov@yandex-team.ru> X-Mailer: git-send-email 2.48.1 In-Reply-To: <20250910193112.1220763-1-vsementsov@yandex-team.ru> References: <20250910193112.1220763-1-vsementsov@yandex-team.ru> MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: quoted-printable Received-SPF: pass (zohomail.com: domain of gnu.org designates 209.51.188.17 as permitted sender) client-ip=209.51.188.17; envelope-from=qemu-devel-bounces+importer=patchew.org@nongnu.org; helo=lists.gnu.org; Received-SPF: pass client-ip=2a02:6b8:c41:1300:1:45:d181:df01; envelope-from=vsementsov@yandex-team.ru; helo=forwardcorp1d.mail.yandex.net 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, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, DKIM_VALID_EF=-0.1, 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+importer=patchew.org@nongnu.org Sender: qemu-devel-bounces+importer=patchew.org@nongnu.org X-ZohoMail-DKIM: pass (identity @yandex-team.ru) X-ZM-MESSAGEID: 1757532736377116600 In migration we want to pass fd "as is", not changing its blocking status. The only current user of these fds is CPR state (through VMSTATE_FD), which of-course doesn't want to modify fds on target when source is still running and use these fds. Suggested-by: Daniel P. Berrang=C3=A9 Signed-off-by: Vladimir Sementsov-Ogievskiy Reviewed-by: Daniel P. Berrang=C3=A9 Reviewed-by: Peter Xu --- include/io/channel.h | 1 + io/channel-socket.c | 13 +++++++++---- migration/qemu-file.c | 3 ++- 3 files changed, 12 insertions(+), 5 deletions(-) diff --git a/include/io/channel.h b/include/io/channel.h index 234e5db70d..12266256a8 100644 --- a/include/io/channel.h +++ b/include/io/channel.h @@ -36,6 +36,7 @@ OBJECT_DECLARE_TYPE(QIOChannel, QIOChannelClass, =20 #define QIO_CHANNEL_READ_FLAG_MSG_PEEK 0x1 #define QIO_CHANNEL_READ_FLAG_RELAXED_EOF 0x2 +#define QIO_CHANNEL_READ_FLAG_FD_PRESERVE_BLOCKING 0x4 =20 typedef enum QIOChannelFeature QIOChannelFeature; =20 diff --git a/io/channel-socket.c b/io/channel-socket.c index 3b7ca924ff..21f8f2e0c5 100644 --- a/io/channel-socket.c +++ b/io/channel-socket.c @@ -464,7 +464,8 @@ static void qio_channel_socket_finalize(Object *obj) =20 #ifndef WIN32 static void qio_channel_socket_copy_fds(struct msghdr *msg, - int **fds, size_t *nfds) + int **fds, size_t *nfds, + bool preserve_blocking) { struct cmsghdr *cmsg; =20 @@ -497,8 +498,10 @@ static void qio_channel_socket_copy_fds(struct msghdr = *msg, continue; } =20 - /* O_NONBLOCK is preserved across SCM_RIGHTS so reset it */ - qemu_socket_set_block(fd); + if (!preserve_blocking) { + /* O_NONBLOCK is preserved across SCM_RIGHTS so reset it */ + qemu_socket_set_block(fd); + } =20 #ifndef MSG_CMSG_CLOEXEC qemu_set_cloexec(fd); @@ -556,7 +559,9 @@ static ssize_t qio_channel_socket_readv(QIOChannel *ioc, } =20 if (fds && nfds) { - qio_channel_socket_copy_fds(&msg, fds, nfds); + qio_channel_socket_copy_fds( + &msg, fds, nfds, + flags & QIO_CHANNEL_READ_FLAG_FD_PRESERVE_BLOCKING); } =20 return ret; diff --git a/migration/qemu-file.c b/migration/qemu-file.c index b6ac190034..d5c6e7ec61 100644 --- a/migration/qemu-file.c +++ b/migration/qemu-file.c @@ -340,7 +340,8 @@ static ssize_t coroutine_mixed_fn qemu_fill_buffer(QEMU= File *f) =20 do { struct iovec iov =3D { f->buf + pending, IO_BUF_SIZE - pending }; - len =3D qio_channel_readv_full(f->ioc, &iov, 1, pfds, pnfd, 0, + len =3D qio_channel_readv_full(f->ioc, &iov, 1, pfds, pnfd, + QIO_CHANNEL_READ_FLAG_FD_PRESERVE_BLO= CKING, &local_error); if (len =3D=3D QIO_CHANNEL_ERR_BLOCK) { if (qemu_in_coroutine()) { --=20 2.48.1