From: Kevin Wolf Date: Wed, 2 Mar 2016 11:16:44 +0000 (+0100) Subject: blockdev: Snapshotting must not open second instance of old top X-Git-Url: http://git.maquefel.me/?a=commitdiff_plain;h=f86b8b584b114d68036bf576057f51caec7b94ba;p=qemu.git blockdev: Snapshotting must not open second instance of old top Calling bdrv_img_create() with a size of -1 means that it determines the size automatically by opening the backing file. However, in the case of live snapshots, the backing file is already opened and we must avoid opening the same image twice at the same time. Apart from that, just getting the size from the already existing BDS is a lot less overhead than opening a new instance. Signed-off-by: Kevin Wolf Reviewed-by: Jeff Cody --- diff --git a/blockdev.c b/blockdev.c index 0f20c6511f..e1c1540010 100644 --- a/blockdev.c +++ b/blockdev.c @@ -1732,10 +1732,15 @@ static void external_snapshot_prepare(BlkActionState *common, /* create new image w/backing file */ mode = s->has_mode ? s->mode : NEW_IMAGE_MODE_ABSOLUTE_PATHS; if (mode != NEW_IMAGE_MODE_EXISTING) { + int64_t size = bdrv_getlength(state->old_bs); + if (size < 0) { + error_setg_errno(errp, -size, "bdrv_getlength failed"); + return; + } bdrv_img_create(new_image_file, format, state->old_bs->filename, state->old_bs->drv->format_name, - NULL, -1, flags, &local_err, false); + NULL, size, flags, &local_err, false); if (local_err) { error_propagate(errp, local_err); return;