From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:37138) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1cT92I-0003T6-Sy for qemu-devel@nongnu.org; Mon, 16 Jan 2017 10:17:31 -0500 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1cT92G-0007m3-CA for qemu-devel@nongnu.org; Mon, 16 Jan 2017 10:17:30 -0500 Received: from mx-v6.kamp.de ([2a02:248:0:51::16]:49908 helo=mx01.kamp.de) by eggs.gnu.org with esmtps (TLS1.0:DHE_RSA_AES_256_CBC_SHA1:32) (Exim 4.71) (envelope-from ) id 1cT92G-0007kt-30 for qemu-devel@nongnu.org; Mon, 16 Jan 2017 10:17:28 -0500 From: Peter Lieven Date: Mon, 16 Jan 2017 16:17:12 +0100 Message-Id: <1484579832-18589-1-git-send-email-pl@kamp.de> Subject: [Qemu-devel] [PATCH] block/iscsi: avoid data corruption with cache=writeback List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: qemu-devel@nongnu.org Cc: pbonzini@redhat.com, qemu-block@nongnu.org, Peter Lieven , qemu-stable@nongnu.org nb_cls_shrunk in iscsi_allocmap_update can become -1 if the request starts and ends within the same cluster. This results in passing -1 to bitmap_set and bitmap_clear and they don't handle negative values properly. In the end this leads to data corruption. Fixes: e1123a3b40a1a9a625a29c8ed4debb7e206ea690 Cc: qemu-stable@nongnu.org Signed-off-by: Peter Lieven --- block/iscsi.c | 8 ++++++-- 1 file changed, 6 insertions(+), 2 deletions(-) diff --git a/block/iscsi.c b/block/iscsi.c index 6aeeb9e..1860f1b 100644 --- a/block/iscsi.c +++ b/block/iscsi.c @@ -499,14 +499,18 @@ iscsi_allocmap_update(IscsiLun *iscsilun, int64_t sector_num, if (allocated) { bitmap_set(iscsilun->allocmap, cl_num_expanded, nb_cls_expanded); } else { - bitmap_clear(iscsilun->allocmap, cl_num_shrunk, nb_cls_shrunk); + if (nb_cls_shrunk > 0) { + bitmap_clear(iscsilun->allocmap, cl_num_shrunk, nb_cls_shrunk); + } } if (iscsilun->allocmap_valid == NULL) { return; } if (valid) { - bitmap_set(iscsilun->allocmap_valid, cl_num_shrunk, nb_cls_shrunk); + if (nb_cls_shrunk > 0) { + bitmap_set(iscsilun->allocmap_valid, cl_num_shrunk, nb_cls_shrunk); + } } else { bitmap_clear(iscsilun->allocmap_valid, cl_num_expanded, nb_cls_expanded); -- 1.9.1