From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([208.118.235.92]:60313) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1SRlnE-0002C8-1I for qemu-devel@nongnu.org; Tue, 08 May 2012 10:53:40 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1SRln8-00083C-SF for qemu-devel@nongnu.org; Tue, 08 May 2012 10:53:35 -0400 Received: from mail-pb0-f45.google.com ([209.85.160.45]:35271) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1SRln8-0007gL-J5 for qemu-devel@nongnu.org; Tue, 08 May 2012 10:53:30 -0400 Received: by mail-pb0-f45.google.com with SMTP id ro12so10991250pbb.4 for ; Tue, 08 May 2012 07:53:29 -0700 (PDT) Sender: Paolo Bonzini From: Paolo Bonzini Date: Tue, 8 May 2012 16:51:58 +0200 Message-Id: <1336488722-13120-19-git-send-email-pbonzini@redhat.com> In-Reply-To: <1336488722-13120-1-git-send-email-pbonzini@redhat.com> References: <1336488722-13120-1-git-send-email-pbonzini@redhat.com> Subject: [Qemu-devel] [PATCH 1.1 18/22] stream: do not copy unallocated sectors from the base List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: qemu-devel@nongnu.org Cc: kwolf@redhat.com, stefanha@linux.vnet.ibm.com Unallocated sectors should really never be accessed by the guest, so there's no need to copy them during the streaming process. If they are read by the guest during streaming, guest-initiated copy-on-read will copy them (we're in the base == NULL case, which enables copy on read). If they are read after we disconnect the image from the base, they will read as zeroes anyway. Signed-off-by: Paolo Bonzini --- This is a semantic change. We could delay it to 1.2 as a bug fix, or do it now to avoid changing semantics in the next release. block/stream.c | 18 ++++-------------- tests/qemu-iotests/030 | 5 +++-- 2 files changed, 7 insertions(+), 16 deletions(-) diff --git a/block/stream.c b/block/stream.c index a2c8f67..608a860 100644 --- a/block/stream.c +++ b/block/stream.c @@ -130,14 +130,9 @@ static int coroutine_fn is_allocated_base(BlockDriverState *top, */ intermediate = top->backing_hd; - while (intermediate) { + while (intermediate != base) { int pnum_inter; - /* reached base */ - if (intermediate == base) { - *pnum = n; - return 1; - } ret = bdrv_co_is_allocated(intermediate, sector_num, nb_sectors, &pnum_inter); if (ret < 0) { @@ -160,6 +155,7 @@ static int coroutine_fn is_allocated_base(BlockDriverState *top, intermediate = intermediate->backing_hd; } + *pnum = n; return 1; } @@ -203,14 +199,8 @@ wait: break; } - if (base) { - ret = is_allocated_base(bs, base, sector_num, - STREAM_BUFFER_SIZE / BDRV_SECTOR_SIZE, &n); - } else { - ret = bdrv_co_is_allocated(bs, sector_num, - STREAM_BUFFER_SIZE / BDRV_SECTOR_SIZE, - &n); - } + ret = is_allocated_base(bs, base, sector_num, + STREAM_BUFFER_SIZE / BDRV_SECTOR_SIZE, &n); trace_stream_one_iteration(s, sector_num, n, ret); if (ret == 0) { if (s->common.speed) { diff --git a/tests/qemu-iotests/030 b/tests/qemu-iotests/030 index 0aa7a0a..61cb027 100755 --- a/tests/qemu-iotests/030 +++ b/tests/qemu-iotests/030 @@ -82,8 +82,9 @@ class TestSingleDrive(ImageStreamingTestCase): self.assert_no_active_streams() self.vm.shutdown() - self.assertFalse('sectors not allocated' in qemu_io('-c', 'map', test_img), - 'image file not fully populated after streaming') + self.assertEqual(qemu_io('-c', 'map', backing_img), + qemu_io('-c', 'map', test_img), + 'image file map does not match backing file after streaming') def test_stream_partial(self): self.assert_no_active_streams() -- 1.7.10.1