#include "qemu/error-report.h"
#include "qemu/cutils.h"
+static void qcow2_free_single_snapshot(BlockDriverState *bs, int i)
+{
+ BDRVQcow2State *s = bs->opaque;
+
+ assert(i >= 0 && i < s->nb_snapshots);
+ g_free(s->snapshots[i].name);
+ g_free(s->snapshots[i].id_str);
+ g_free(s->snapshots[i].unknown_extra_data);
+ memset(&s->snapshots[i], 0, sizeof(s->snapshots[i]));
+}
+
void qcow2_free_snapshots(BlockDriverState *bs)
{
BDRVQcow2State *s = bs->opaque;
int i;
for(i = 0; i < s->nb_snapshots; i++) {
- g_free(s->snapshots[i].name);
- g_free(s->snapshots[i].id_str);
- g_free(s->snapshots[i].unknown_extra_data);
+ qcow2_free_single_snapshot(bs, i);
}
g_free(s->snapshots);
s->snapshots = NULL;
* If @repair is true, try to repair a broken snapshot table instead
* of just returning an error:
*
+ * - If the snapshot table was too long, set *nb_clusters_reduced to
+ * the number of snapshots removed off the end.
+ * The caller will update the on-disk nb_snapshots accordingly;
+ * this leaks clusters, but is safe.
+ * (The on-disk information must be updated before
+ * qcow2_check_refcounts(), because that function relies on
+ * s->nb_snapshots to reflect the on-disk value.)
+ *
* - If there were snapshots with too much extra metadata, increment
* *extra_data_dropped for each.
* This requires the caller to eventually rewrite the whole snapshot
* extra data.)
*/
static int qcow2_do_read_snapshots(BlockDriverState *bs, bool repair,
+ int *nb_clusters_reduced,
int *extra_data_dropped,
Error **errp)
{
QCowSnapshotExtraData extra;
QCowSnapshot *sn;
int i, id_str_size, name_size;
- int64_t offset;
+ int64_t offset, pre_sn_offset;
uint64_t table_length = 0;
int ret;
for(i = 0; i < s->nb_snapshots; i++) {
bool truncate_unknown_extra_data = false;
+ pre_sn_offset = offset;
table_length = ROUND_UP(table_length, 8);
/* Read statically sized part of the snapshot header */
if (table_length > QCOW_MAX_SNAPSHOTS_SIZE ||
offset - s->snapshots_offset > INT_MAX)
{
- ret = -EFBIG;
- error_setg(errp, "Snapshot table is too big");
- goto fail;
+ if (!repair) {
+ ret = -EFBIG;
+ error_setg(errp, "Snapshot table is too big");
+ error_append_hint(errp, "You can force-remove all %u "
+ "overhanging snapshots with qemu-img check "
+ "-r all\n", s->nb_snapshots - i);
+ goto fail;
+ }
+
+ fprintf(stderr, "Discarding %u overhanging snapshots (snapshot "
+ "table is too big)\n", s->nb_snapshots - i);
+
+ *nb_clusters_reduced += (s->nb_snapshots - i);
+
+ /* Discard current snapshot also */
+ qcow2_free_single_snapshot(bs, i);
+
+ /*
+ * This leaks all the rest of the snapshot table and the
+ * snapshots' clusters, but we run in check -r all mode,
+ * so qcow2_check_refcounts() will take care of it.
+ */
+ s->nb_snapshots = i;
+ offset = pre_sn_offset;
+ break;
}
}
int qcow2_read_snapshots(BlockDriverState *bs, Error **errp)
{
- return qcow2_do_read_snapshots(bs, false, NULL, errp);
+ return qcow2_do_read_snapshots(bs, false, NULL, NULL, errp);
}
/* add at the end of the file a new list of snapshots */
{
BDRVQcow2State *s = bs->opaque;
Error *local_err = NULL;
+ int nb_clusters_reduced = 0;
int extra_data_dropped = 0;
int ret;
struct {
s->snapshots_offset = be64_to_cpu(snapshot_table_pointer.snapshots_offset);
s->nb_snapshots = be32_to_cpu(snapshot_table_pointer.nb_snapshots);
+ if (s->nb_snapshots > QCOW_MAX_SNAPSHOTS && (fix & BDRV_FIX_ERRORS)) {
+ fprintf(stderr, "Discarding %u overhanging snapshots\n",
+ s->nb_snapshots - QCOW_MAX_SNAPSHOTS);
+
+ nb_clusters_reduced += s->nb_snapshots - QCOW_MAX_SNAPSHOTS;
+ s->nb_snapshots = QCOW_MAX_SNAPSHOTS;
+ }
+
ret = qcow2_validate_table(bs, s->snapshots_offset, s->nb_snapshots,
sizeof(QCowSnapshotHeader),
sizeof(QCowSnapshotHeader) * QCOW_MAX_SNAPSHOTS,
result->check_errors++;
error_reportf_err(local_err, "ERROR ");
+ if (s->nb_snapshots > QCOW_MAX_SNAPSHOTS) {
+ fprintf(stderr, "You can force-remove all %u overhanging snapshots "
+ "with qemu-img check -r all\n",
+ s->nb_snapshots - QCOW_MAX_SNAPSHOTS);
+ }
+
/* We did not read the snapshot table, so invalidate this information */
s->snapshots_offset = 0;
s->nb_snapshots = 0;
qemu_co_mutex_unlock(&s->lock);
ret = qcow2_do_read_snapshots(bs, fix & BDRV_FIX_ERRORS,
- &extra_data_dropped, &local_err);
+ &nb_clusters_reduced, &extra_data_dropped,
+ &local_err);
qemu_co_mutex_lock(&s->lock);
if (ret < 0) {
result->check_errors++;
return ret;
}
- result->corruptions += extra_data_dropped;
+ result->corruptions += nb_clusters_reduced + extra_data_dropped;
+
+ if (nb_clusters_reduced) {
+ /*
+ * Update image header now, because:
+ * (1) qcow2_check_refcounts() relies on s->nb_snapshots to be
+ * the same as what the image header says,
+ * (2) this leaks clusters, but qcow2_check_refcounts() will
+ * fix that.
+ */
+ assert(fix & BDRV_FIX_ERRORS);
+
+ snapshot_table_pointer.nb_snapshots = cpu_to_be32(s->nb_snapshots);
+ ret = bdrv_pwrite_sync(bs->file, offsetof(QCowHeader, nb_snapshots),
+ &snapshot_table_pointer.nb_snapshots,
+ sizeof(snapshot_table_pointer.nb_snapshots));
+ if (ret < 0) {
+ result->check_errors++;
+ fprintf(stderr, "ERROR failed to update the snapshot count in the "
+ "image header: %s\n", strerror(-ret));
+ return ret;
+ }
+
+ result->corruptions_fixed += nb_clusters_reduced;
+ result->corruptions -= nb_clusters_reduced;
+ }
+
+ /*
+ * All of v3 images' snapshot table entries need to have at least
+ * 16 bytes of extra data.
+ */
+ if (s->qcow_version >= 3) {
+ int i;
+ for (i = 0; i < s->nb_snapshots; i++) {
+ if (s->snapshots[i].extra_data_size <
+ sizeof_field(QCowSnapshotExtraData, vm_state_size_large) +
+ sizeof_field(QCowSnapshotExtraData, disk_size))
+ {
+ result->corruptions++;
+ fprintf(stderr, "%s snapshot table entry %i is incomplete\n",
+ fix & BDRV_FIX_ERRORS ? "Repairing" : "ERROR", i);
+ }
+ }
+ }
return 0;
}
return ret;
}
new_l1_bytes = sn->l1_size * sizeof(uint64_t);
- new_l1_table = qemu_try_blockalign(bs->file->bs,
- ROUND_UP(new_l1_bytes, 512));
+ new_l1_table = qemu_try_blockalign(bs->file->bs, new_l1_bytes);
if (new_l1_table == NULL) {
return -ENOMEM;
}
projects / mirror_qemu.git / blobdiff