From 712a6ef0d0d3bbc91953305ad8e7e96f82f19cf0 Mon Sep 17 00:00:00 2001 From: Max Reitz Date: Mon, 4 Nov 2013 22:32:27 +0100 Subject: [PATCH 34/87] qcow2: Use pread for inactive L1 in overlap check RH-Author: Max Reitz Message-id: <1383604354-12743-37-git-send-email-mreitz@redhat.com> Patchwork-id: 55336 O-Subject: [RHEL-7.0 qemu-kvm PATCH 36/43] qcow2: Use pread for inactive L1 in overlap check Bugzilla: 1004347 RH-Acked-by: Kevin Wolf RH-Acked-by: Laszlo Ersek RH-Acked-by: Fam Zheng RH-Acked-by: Stefan Hajnoczi BZ: 1004347 Currently, qcow2_check_metadata_overlap uses bdrv_read to read inactive L1 tables from disk. The number of sectors to read is calculated through a truncating integer division, therefore, if the L1 table size is not a multiple of the sector size, the final entries will not be read and their entries in memory remain undefined (from the g_malloc). Using bdrv_pread fixes this. Signed-off-by: Max Reitz Signed-off-by: Kevin Wolf (cherry picked from commit 998b959c1e59044f5d5f64c482f4ce8facc8e0bc) Signed-off-by: Max Reitz --- block/qcow2-refcount.c | 7 +++---- 1 file changed, 3 insertions(+), 4 deletions(-) Signed-off-by: Miroslav Rezanina --- block/qcow2-refcount.c | 7 +++---- 1 files changed, 3 insertions(+), 4 deletions(-) diff --git a/block/qcow2-refcount.c b/block/qcow2-refcount.c index 34fcf2f..5c5683d 100644 --- a/block/qcow2-refcount.c +++ b/block/qcow2-refcount.c @@ -1701,12 +1701,11 @@ int qcow2_check_metadata_overlap(BlockDriverState *bs, int chk, int64_t offset, for (i = 0; i < s->nb_snapshots; i++) { uint64_t l1_ofs = s->snapshots[i].l1_table_offset; uint32_t l1_sz = s->snapshots[i].l1_size; - uint64_t *l1 = g_malloc(l1_sz * sizeof(uint64_t)); + uint64_t l1_sz2 = l1_sz * sizeof(uint64_t); + uint64_t *l1 = g_malloc(l1_sz2); int ret; - ret = bdrv_read(bs->file, l1_ofs / BDRV_SECTOR_SIZE, (uint8_t *)l1, - l1_sz * sizeof(uint64_t) / BDRV_SECTOR_SIZE); - + ret = bdrv_pread(bs->file, l1_ofs, l1, l1_sz2); if (ret < 0) { g_free(l1); return ret; -- 1.7.1