@@ -152,7 +152,9 @@ fail:
}
/* add at the end of the file a new list of snapshots */
-static int qcow2_write_snapshots(BlockDriverState *bs, Error **errp)
+static int qcow2_write_snapshots(BlockDriverState *bs,
+ Error **errp,
+ Error **errp_rollback)
{
BDRVQcowState *s = bs->opaque;
QCowSnapshot *sn;
@@ -162,9 +164,9 @@ static int qcow2_write_snapshots(BlockDriverState *bs, Error **errp)
struct {
uint32_t nb_snapshots;
uint64_t snapshots_offset;
- } QEMU_PACKED header_data;
+ } QEMU_PACKED header_data, header_data_old;
int64_t offset, snapshots_offset;
- int ret;
+ int ret, ret0;
/* compute the size of the snapshots */
offset = 0;
@@ -192,7 +194,7 @@ static int qcow2_write_snapshots(BlockDriverState *bs, Error **errp)
error_setg_errno(errp, -ret,
"Failed in flush after snapshot list cluster "
"allocation");
- goto fail;
+ goto dealloc_sn_table;
}
/* The snapshot list position has not yet been updated, so these clusters
@@ -203,7 +205,7 @@ static int qcow2_write_snapshots(BlockDriverState *bs, Error **errp)
"Failed in overlap check for snapshot list cluster "
"at %" PRIi64 " with size %d",
offset, snapshots_size);
- goto fail;
+ goto dealloc_sn_table;
}
@@ -240,7 +242,7 @@ static int qcow2_write_snapshots(BlockDriverState *bs, Error **errp)
"Failed in write of snapshot header at %"
PRIi64 " with size %zu",
offset, sizeof(h));
- goto fail;
+ goto dealloc_sn_table;
}
offset += sizeof(h);
@@ -250,7 +252,7 @@ static int qcow2_write_snapshots(BlockDriverState *bs, Error **errp)
"Failed in write of extra snapshot data at %"
PRIi64 " with size %zu",
offset, sizeof(extra));
- goto fail;
+ goto dealloc_sn_table;
}
offset += sizeof(extra);
@@ -260,7 +262,7 @@ static int qcow2_write_snapshots(BlockDriverState *bs, Error **errp)
"Failed in write of snapshot id string at %"
PRIi64 " with size %d",
offset, id_str_size);
- goto fail;
+ goto dealloc_sn_table;
}
offset += id_str_size;
@@ -270,7 +272,7 @@ static int qcow2_write_snapshots(BlockDriverState *bs, Error **errp)
"Failed in write of snapshot name string at %"
PRIi64 " with size %d",
offset, name_size);
- goto fail;
+ goto dealloc_sn_table;
}
offset += name_size;
}
@@ -283,7 +285,18 @@ static int qcow2_write_snapshots(BlockDriverState *bs, Error **errp)
if (ret < 0) {
error_setg_errno(errp, -ret,
"Failed in flush after snapshot list update");
- goto fail;
+ goto dealloc_sn_table;
+ }
+
+ /* Start the qcow2 header update */
+ ret = bdrv_pread(bs->file, offsetof(QCowHeader, nb_snapshots),
+ &header_data_old, sizeof(header_data_old));
+ if (ret < 0) {
+ error_setg_errno(errp, -ret,
+ "Failed to read of image header at %zu with size %zu",
+ offsetof(QCowHeader, nb_snapshots),
+ sizeof(header_data_old));
+ goto dealloc_sn_table;
}
QEMU_BUILD_BUG_ON(offsetof(QCowHeader, snapshots_offset) !=
@@ -299,7 +312,7 @@ static int qcow2_write_snapshots(BlockDriverState *bs, Error **errp)
"Failed in update of image header at %zu with size %zu",
offsetof(QCowHeader, nb_snapshots),
sizeof(header_data));
- goto fail;
+ goto restore_header;
}
/* free the old snapshot table */
@@ -309,11 +322,29 @@ static int qcow2_write_snapshots(BlockDriverState *bs, Error **errp)
s->snapshots_size = snapshots_size;
return 0;
-fail:
+restore_header:
+ ret0 = bdrv_pwrite_sync(bs->file, offsetof(QCowHeader, nb_snapshots),
+ &header_data_old, sizeof(header_data_old));
+ if (ret0 < 0) {
+ error_setg_errno(errp_rollback, -ret0,
+ "Failed to restore image header at %zu with size %zu "
+ "during rollback",
+ offsetof(QCowHeader, nb_snapshots),
+ sizeof(header_data));
+ goto fail;
+ }
+
+dealloc_sn_table:
if (snapshots_offset > 0) {
- qcow2_free_clusters(bs, snapshots_offset, snapshots_size,
- QCOW2_DISCARD_ALWAYS);
+ ret0 = qcow2_free_clusters(bs, snapshots_offset, snapshots_size,
+ QCOW2_DISCARD_ALWAYS);
+ if (ret0 < 0) {
+ error_setg_errno(errp_rollback, -ret0,
+ "Failed to free snapshot table during rollback");
+ }
}
+
+fail:
if (errp) {
g_assert(error_is_set(errp));
}
@@ -481,7 +512,7 @@ void qcow2_snapshot_create(BlockDriverState *bs,
s->snapshots = new_snapshot_list;
s->snapshots[s->nb_snapshots++] = *sn;
- ret = qcow2_write_snapshots(bs, errp);
+ ret = qcow2_write_snapshots(bs, errp, NULL);
if (ret < 0) {
g_free(s->snapshots);
s->snapshots = old_snapshot_list;
@@ -656,7 +687,7 @@ int qcow2_snapshot_delete(BlockDriverState *bs,
s->snapshots + snapshot_index + 1,
(s->nb_snapshots - snapshot_index - 1) * sizeof(sn));
s->nb_snapshots--;
- ret = qcow2_write_snapshots(bs, errp);
+ ret = qcow2_write_snapshots(bs, errp, NULL);
if (ret < 0) {
return ret;
}