| Message ID | 1381308176-22635-1-git-send-email-mreitz@redhat.com |
|---|---|
| State | New |
| Headers | show |
Am 09.10.2013 um 10:42 hat Max Reitz geschrieben: > 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 <mreitz@redhat.com> Thanks, applied to the block branch. Kevin
diff --git a/block/qcow2-refcount.c b/block/qcow2-refcount.c index 2d67885..4cb9c23 100644 --- a/block/qcow2-refcount.c +++ b/block/qcow2-refcount.c @@ -1719,12 +1719,11 @@ 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;
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 <mreitz@redhat.com> --- block/qcow2-refcount.c | 7 +++---- 1 file changed, 3 insertions(+), 4 deletions(-)