diff options
| -rw-r--r-- | block/qcow2-snapshot.c | 16 |
1 files changed, 11 insertions, 5 deletions
diff --git a/block/qcow2-snapshot.c b/block/qcow2-snapshot.c index 74823a5ebf..e32bcf084c 100644 --- a/block/qcow2-snapshot.c +++ b/block/qcow2-snapshot.c @@ -317,7 +317,8 @@ int qcow2_snapshot_goto(BlockDriverState *bs, const char *snapshot_id) { BDRVQcowState *s = bs->opaque; QCowSnapshot *sn; - int i, snapshot_index, l1_size2; + int i, snapshot_index; + int cur_l1_bytes, sn_l1_bytes; snapshot_index = find_snapshot_by_id_or_name(bs, snapshot_id); if (snapshot_index < 0) @@ -330,14 +331,19 @@ int qcow2_snapshot_goto(BlockDriverState *bs, const char *snapshot_id) if (qcow2_grow_l1_table(bs, sn->l1_size, true) < 0) goto fail; - s->l1_size = sn->l1_size; - l1_size2 = s->l1_size * sizeof(uint64_t); + cur_l1_bytes = s->l1_size * sizeof(uint64_t); + sn_l1_bytes = sn->l1_size * sizeof(uint64_t); + + if (cur_l1_bytes > sn_l1_bytes) { + memset(s->l1_table + sn->l1_size, 0, cur_l1_bytes - sn_l1_bytes); + } + /* copy the snapshot l1 table to the current l1 table */ if (bdrv_pread(bs->file, sn->l1_table_offset, - s->l1_table, l1_size2) != l1_size2) + s->l1_table, sn_l1_bytes) < 0) goto fail; if (bdrv_pwrite_sync(bs->file, s->l1_table_offset, - s->l1_table, l1_size2) < 0) + s->l1_table, cur_l1_bytes) < 0) goto fail; for(i = 0;i < s->l1_size; i++) { be64_to_cpus(&s->l1_table[i]); |