From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from [140.186.70.92] (port=60176 helo=eggs.gnu.org) by lists.gnu.org with esmtp (Exim 4.43) id 1PwXZO-000473-M8 for qemu-devel@nongnu.org; Mon, 07 Mar 2011 05:21:45 -0500 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1PwXDy-0008Gs-8q for qemu-devel@nongnu.org; Mon, 07 Mar 2011 04:59:38 -0500 Received: from mx1.redhat.com ([209.132.183.28]:27323) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1PwXDy-0008GO-0b for qemu-devel@nongnu.org; Mon, 07 Mar 2011 04:59:34 -0500 Message-ID: <4D74ACFE.40908@redhat.com> Date: Mon, 07 Mar 2011 11:01:34 +0100 From: Kevin Wolf MIME-Version: 1.0 References: <1299158036-18481-1-git-send-email-Jes.Sorensen@redhat.com> In-Reply-To: <1299158036-18481-1-git-send-email-Jes.Sorensen@redhat.com> Content-Type: text/plain; charset=ISO-8859-15 Content-Transfer-Encoding: 7bit Subject: [Qemu-devel] Re: [PATCH v2] Improve error handling in do_snapshot_blkdev() List-Id: qemu-devel.nongnu.org List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Jes.Sorensen@redhat.com Cc: qemu-devel@nongnu.org, stefanha@linux.vnet.ibm.com Am 03.03.2011 14:13, schrieb Jes.Sorensen@redhat.com: > From: Jes Sorensen > > In case we cannot open the newly created snapshot image, try to fall > back to the original image file and continue running on that, which > should prevent the guest from aborting. > > This is a corner case which can happen if the admin by mistake > specifies the snapshot file on a virtual file system which does not > support O_DIRECT. bdrv_create() does not use O_DIRECT, but the > following open in bdrv_open() does and will then fail. > > Signed-off-by: Jes Sorensen > --- > blockdev.c | 30 ++++++++++++++++++++++++------ > 1 files changed, 24 insertions(+), 6 deletions(-) > > diff --git a/blockdev.c b/blockdev.c > index 0690cc8..f52fe8f 100644 > --- a/blockdev.c > +++ b/blockdev.c > @@ -574,9 +574,10 @@ int do_snapshot_blkdev(Monitor *mon, const QDict *qdict, QObject **ret_data) > const char *filename = qdict_get_try_str(qdict, "snapshot_file"); > const char *format = qdict_get_try_str(qdict, "format"); > BlockDriverState *bs; > - BlockDriver *drv, *proto_drv; > + BlockDriver *drv, *old_drv, *proto_drv; > int ret = 0; > int flags; > + char old_filename[1024]; > > if (!filename) { > qerror_report(QERR_MISSING_PARAMETER, "snapshot_file"); > @@ -591,6 +592,12 @@ int do_snapshot_blkdev(Monitor *mon, const QDict *qdict, QObject **ret_data) > goto out; > } > > + strncpy(old_filename, bs->filename, sizeof(old_filename)); > + old_filename[1023] = '\0'; qemu has pstrcpy() from cutils.c for this. > + > + old_drv = bs->drv; > + flags = bs->open_flags; > + > if (!format) { > format = "qcow2"; > } > @@ -610,7 +617,7 @@ int do_snapshot_blkdev(Monitor *mon, const QDict *qdict, QObject **ret_data) > } > > ret = bdrv_img_create(filename, format, bs->filename, > - bs->drv->format_name, NULL, -1, bs->open_flags); > + bs->drv->format_name, NULL, -1, flags); > if (ret) { > goto out; > } > @@ -618,15 +625,26 @@ int do_snapshot_blkdev(Monitor *mon, const QDict *qdict, QObject **ret_data) > qemu_aio_flush(); > bdrv_flush(bs); > > - flags = bs->open_flags; > bdrv_close(bs); > ret = bdrv_open(bs, filename, flags, drv); > /* > - * If reopening the image file we just created fails, we really > - * are in trouble :( > + * If reopening the image file we just created fails, fall back > + * and try to re-open the original image. If that fails too, we > + * are in serious trouble. > */ > if (ret != 0) { > - abort(); > + qerror_report(QERR_OPEN_FILE_FAILED, filename); > + error_printf("do_snapshot_blkdev(): Unable to open newly created " > + "snapshot file: \n"); > + error_printf(" %s. Attempting to revert to original image %s\n", That should probably be a colon in "%s: Attempting..." Also, is the leading space intentional? Kevin