From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:42495) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1Xguk6-0007nt-02 for qemu-devel@nongnu.org; Wed, 22 Oct 2014 08:10:24 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1Xgujz-0005z3-RT for qemu-devel@nongnu.org; Wed, 22 Oct 2014 08:10:17 -0400 Received: from mx1.redhat.com ([209.132.183.28]:57070) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1Xgujz-0005yu-JX for qemu-devel@nongnu.org; Wed, 22 Oct 2014 08:10:11 -0400 From: Max Reitz Date: Wed, 22 Oct 2014 14:09:38 +0200 Message-Id: <1413979783-1549-13-git-send-email-mreitz@redhat.com> In-Reply-To: <1413979783-1549-1-git-send-email-mreitz@redhat.com> References: <1413979783-1549-1-git-send-email-mreitz@redhat.com> Subject: [Qemu-devel] [PATCH v8 12/17] qcow2: Fix refcount blocks beyond image end List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: qemu-devel@nongnu.org Cc: Kevin Wolf , =?UTF-8?q?Beno=C3=AEt=20Canet?= , Stefan Hajnoczi , Max Reitz If the qcow2 check function detects a refcount block located beyond the image end, grow the image appropriately. This cannot break anything and is the logical fix for such a case. Signed-off-by: Max Reitz --- block/qcow2-refcount.c | 67 +++++++++++++++++++++++++++++++++++++++++++++++--- 1 file changed, 63 insertions(+), 4 deletions(-) diff --git a/block/qcow2-refcount.c b/block/qcow2-refcount.c index c92e1fc..b87eafc 100644 --- a/block/qcow2-refcount.c +++ b/block/qcow2-refcount.c @@ -1575,7 +1575,7 @@ static int check_refblocks(BlockDriverState *bs, BdrvCheckResult *res, int64_t *nb_clusters) { BDRVQcowState *s = bs->opaque; - int64_t i; + int64_t i, size; int ret; for(i = 0; i < s->refcount_table_size; i++) { @@ -1592,9 +1592,68 @@ static int check_refblocks(BlockDriverState *bs, BdrvCheckResult *res, } if (cluster >= *nb_clusters) { - fprintf(stderr, "ERROR refcount block %" PRId64 - " is outside image\n", i); - res->corruptions++; + fprintf(stderr, "%s refcount block %" PRId64 " is outside image\n", + fix & BDRV_FIX_ERRORS ? "Repairing" : "ERROR", i); + + if (fix & BDRV_FIX_ERRORS) { + int64_t old_nb_clusters = *nb_clusters; + uint16_t *new_refcount_table; + + if (offset > INT64_MAX - s->cluster_size) { + ret = -EINVAL; + goto resize_fail; + } + + ret = bdrv_truncate(bs->file, offset + s->cluster_size); + if (ret < 0) { + goto resize_fail; + } + size = bdrv_getlength(bs->file); + if (size < 0) { + ret = size; + goto resize_fail; + } + + *nb_clusters = size_to_clusters(s, size); + assert(*nb_clusters >= old_nb_clusters); + + new_refcount_table = g_try_realloc(*refcount_table, + *nb_clusters * + sizeof(**refcount_table)); + if (!new_refcount_table) { + *nb_clusters = old_nb_clusters; + res->check_errors++; + return -ENOMEM; + } + *refcount_table = new_refcount_table; + + memset(*refcount_table + old_nb_clusters, 0, + (*nb_clusters - old_nb_clusters) * + sizeof(**refcount_table)); + + if (cluster >= *nb_clusters) { + ret = -EINVAL; + goto resize_fail; + } + + res->corruptions_fixed++; + ret = inc_refcounts(bs, res, refcount_table, nb_clusters, + offset, s->cluster_size); + if (ret < 0) { + return ret; + } + /* No need to check whether the refcount is now greater than 1: + * This area was just allocated and zeroed, so it can only be + * exactly 1 after inc_refcounts() */ + continue; + +resize_fail: + res->corruptions++; + fprintf(stderr, "ERROR could not resize image: %s\n", + strerror(-ret)); + } else { + res->corruptions++; + } continue; } -- 1.9.3