From patchwork Wed Oct 26 10:39:14 2011 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Gerd Hoffmann X-Patchwork-Id: 121878 Return-Path: X-Original-To: incoming@patchwork.ozlabs.org Delivered-To: patchwork-incoming@bilbo.ozlabs.org Received: from lists.gnu.org (lists.gnu.org [140.186.70.17]) (using TLSv1 with cipher AES256-SHA (256/256 bits)) (Client did not present a certificate) by ozlabs.org (Postfix) with ESMTPS id 00F1B1007DB for ; Wed, 26 Oct 2011 21:40:06 +1100 (EST) Received: from localhost ([::1]:49555 helo=lists.gnu.org) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1RJ0tn-0008WT-Pj for incoming@patchwork.ozlabs.org; Wed, 26 Oct 2011 06:39:55 -0400 Received: from eggs.gnu.org ([140.186.70.92]:46927) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1RJ0ti-0008WJ-IN for qemu-devel@nongnu.org; Wed, 26 Oct 2011 06:39:51 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1RJ0tg-0002KK-UY for qemu-devel@nongnu.org; Wed, 26 Oct 2011 06:39:50 -0400 Received: from mx1.redhat.com ([209.132.183.28]:49951) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1RJ0tg-0002K3-MU for qemu-devel@nongnu.org; Wed, 26 Oct 2011 06:39:48 -0400 Received: from int-mx01.intmail.prod.int.phx2.redhat.com (int-mx01.intmail.prod.int.phx2.redhat.com [10.5.11.11]) by mx1.redhat.com (8.14.4/8.14.4) with ESMTP id p9QAdkSg027973 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-SHA bits=256 verify=OK) for ; Wed, 26 Oct 2011 06:39:46 -0400 Received: from rincewind.home.kraxel.org (ovpn-116-39.ams2.redhat.com [10.36.116.39]) by int-mx01.intmail.prod.int.phx2.redhat.com (8.13.8/8.13.8) with ESMTP id p9QAdV1L025292; Wed, 26 Oct 2011 06:39:43 -0400 Received: by rincewind.home.kraxel.org (Postfix, from userid 500) id 941C240184; Wed, 26 Oct 2011 12:39:14 +0200 (CEST) From: Gerd Hoffmann To: qemu-devel@nongnu.org Date: Wed, 26 Oct 2011 12:39:14 +0200 Message-Id: <1319625554-6020-1-git-send-email-kraxel@redhat.com> X-Scanned-By: MIMEDefang 2.67 on 10.5.11.11 X-detected-operating-system: by eggs.gnu.org: GNU/Linux 2.6 (newer, 3) X-Received-From: 209.132.183.28 Cc: Jiri Denemark , Gerd Hoffmann Subject: [Qemu-devel] [PATCH] migration: flush migration data to disk. X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.14 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: qemu-devel-bounces+incoming=patchwork.ozlabs.org@nongnu.org Sender: qemu-devel-bounces+incoming=patchwork.ozlabs.org@nongnu.org This patch increases robustness when migrating to a file with two little changes: (1) Before closing the migration file handle checks if it happens to be a regular file and if so it issues a fsync. This way the data is flushed to disk before qemu sends the migration completed event. (2) It adds error checking. In case either fsync or close syscall fails pass up the error (and fail migration). Cc: Jiri Denemark Signed-off-by: Gerd Hoffmann --- migration-fd.c | 21 ++++++++++++++++++++- 1 files changed, 20 insertions(+), 1 deletions(-) diff --git a/migration-fd.c b/migration-fd.c index d0aec89..2206494 100644 --- a/migration-fd.c +++ b/migration-fd.c @@ -42,10 +42,29 @@ static int fd_write(MigrationState *s, const void * buf, size_t size) static int fd_close(MigrationState *s) { + struct stat st; + int ret; + DPRINTF("fd_close\n"); if (s->fd != -1) { - close(s->fd); + ret = fstat(s->fd, &st); + if (ret == 0 && S_ISREG(st.st_mode)) { + /* + * If the file handle is a regular file make sure the + * data is flushed to disk before signaling success. + */ + ret = fsync(s->fd); + if (ret != 0) { + perror("migration-fd: fsync"); + return -1; + } + } + ret = close(s->fd); s->fd = -1; + if (ret != 0) { + perror("migration-fd: close"); + return -1; + } } return 0; }