From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from [140.186.70.92] (port=35372 helo=eggs.gnu.org) by lists.gnu.org with esmtp (Exim 4.43) id 1Pv61o-0004tO-Qv for qemu-devel@nongnu.org; Thu, 03 Mar 2011 05:45:06 -0500 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1Pv61n-0004Jc-7l for qemu-devel@nongnu.org; Thu, 03 Mar 2011 05:45:04 -0500 Received: from mx1.redhat.com ([209.132.183.28]:59359) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1Pv61m-0004IT-Vi for qemu-devel@nongnu.org; Thu, 03 Mar 2011 05:45:03 -0500 From: Jes.Sorensen@redhat.com Date: Thu, 3 Mar 2011 11:44:51 +0100 Message-Id: <1299149091-13979-1-git-send-email-Jes.Sorensen@redhat.com> Subject: [Qemu-devel] [PATCH] Improve error handling in do_snapshot_blkdev() List-Id: qemu-devel.nongnu.org List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: qemu-devel@nongnu.org Cc: kwolf@redhat.com, stefanha@linux.vnet.ibm.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..d43df5e 100644 --- a/blockdev.c +++ b/blockdev.c @@ -574,9 +574,12 @@ 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]; + + old_filename[1023] = '\0'; if (!filename) { qerror_report(QERR_MISSING_PARAMETER, "snapshot_file"); @@ -591,6 +594,10 @@ int do_snapshot_blkdev(Monitor *mon, const QDict *qdict, QObject **ret_data) goto out; } + strncpy(old_filename, bs->filename, 1024); + 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", + filename, old_filename); + ret = bdrv_open(bs, old_filename, flags, old_drv); + if (ret != 0) { + error_printf("do_snapshot_blkdev(): Unable to re-open " + "original image - aborting!\n"); + qerror_report(QERR_OPEN_FILE_FAILED, old_filename); + abort(); + } } out: if (ret) { -- 1.7.4