diff options
| -rw-r--r-- | block/qcow2-snapshot.c | 55 |
1 files changed, 41 insertions, 14 deletions
diff --git a/block/qcow2-snapshot.c b/block/qcow2-snapshot.c index 53d9233ba9..a8add9c857 100644 --- a/block/qcow2-snapshot.c +++ b/block/qcow2-snapshot.c @@ -277,7 +277,9 @@ static int find_snapshot_by_id_or_name(BlockDriverState *bs, const char *name) int qcow2_snapshot_create(BlockDriverState *bs, QEMUSnapshotInfo *sn_info) { BDRVQcowState *s = bs->opaque; - QCowSnapshot *snapshots1, sn1, *sn = &sn1; + QCowSnapshot *new_snapshot_list = NULL; + QCowSnapshot *old_snapshot_list = NULL; + QCowSnapshot sn1, *sn = &sn1; int i, ret; uint64_t *l1_table = NULL; int64_t l1_table_offset; @@ -303,16 +305,12 @@ int qcow2_snapshot_create(BlockDriverState *bs, QEMUSnapshotInfo *sn_info) sn->date_nsec = sn_info->date_nsec; sn->vm_clock_nsec = sn_info->vm_clock_nsec; - ret = qcow2_update_snapshot_refcount(bs, s->l1_table_offset, s->l1_size, 1); - if (ret < 0) - goto fail; - /* Allocate the L1 table of the snapshot and copy the current one there. */ l1_table_offset = qcow2_alloc_clusters(bs, s->l1_size * sizeof(uint64_t)); if (l1_table_offset < 0) { + ret = l1_table_offset; goto fail; } - bdrv_flush(bs->file); sn->l1_table_offset = l1_table_offset; sn->l1_size = s->l1_size; @@ -321,22 +319,50 @@ int qcow2_snapshot_create(BlockDriverState *bs, QEMUSnapshotInfo *sn_info) for(i = 0; i < s->l1_size; i++) { l1_table[i] = cpu_to_be64(s->l1_table[i]); } - if (bdrv_pwrite_sync(bs->file, sn->l1_table_offset, - l1_table, s->l1_size * sizeof(uint64_t)) < 0) + + ret = bdrv_pwrite(bs->file, sn->l1_table_offset, l1_table, + s->l1_size * sizeof(uint64_t)); + if (ret < 0) { goto fail; + } + g_free(l1_table); l1_table = NULL; - snapshots1 = g_malloc((s->nb_snapshots + 1) * sizeof(QCowSnapshot)); + /* + * Increase the refcounts of all clusters and make sure everything is + * stable on disk before updating the snapshot table to contain a pointer + * to the new L1 table. + */ + ret = qcow2_update_snapshot_refcount(bs, s->l1_table_offset, s->l1_size, 1); + if (ret < 0) { + goto fail; + } + + ret = bdrv_flush(bs); + if (ret < 0) { + goto fail; + } + + /* Append the new snapshot to the snapshot list */ + new_snapshot_list = g_malloc((s->nb_snapshots + 1) * sizeof(QCowSnapshot)); if (s->snapshots) { - memcpy(snapshots1, s->snapshots, s->nb_snapshots * sizeof(QCowSnapshot)); - g_free(s->snapshots); + memcpy(new_snapshot_list, s->snapshots, + s->nb_snapshots * sizeof(QCowSnapshot)); + old_snapshot_list = s->snapshots; } - s->snapshots = snapshots1; + s->snapshots = new_snapshot_list; s->snapshots[s->nb_snapshots++] = *sn; - if (qcow2_write_snapshots(bs) < 0) + ret = qcow2_write_snapshots(bs); + if (ret < 0) { + g_free(s->snapshots); + s->snapshots = old_snapshot_list; goto fail; + } + + g_free(old_snapshot_list); + #ifdef DEBUG_ALLOC { BdrvCheckResult result = {0}; @@ -349,7 +375,8 @@ fail: g_free(sn->id_str); g_free(sn->name); g_free(l1_table); - return -1; + + return ret; } /* copy the snapshot 'snapshot_name' into the current disk image */ |