*/
#include "qemu/osdep.h"
+#include "sysemu/block-backend.h"
#include "qapi/error.h"
-#include "block/block_int.h"
#include "qcow2.h"
#include "qemu/bswap.h"
#include "qemu/error-report.h"
#include "qemu/cutils.h"
+#include "qemu/memalign.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)
{
int i;
for(i = 0; i < s->nb_snapshots; i++) {
- g_free(s->snapshots[i].name);
- g_free(s->snapshots[i].id_str);
+ qcow2_free_single_snapshot(bs, i);
}
g_free(s->snapshots);
s->snapshots = NULL;
s->nb_snapshots = 0;
}
-int qcow2_read_snapshots(BlockDriverState *bs)
+/*
+ * 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
+ * table, which requires cluster allocation. Therefore, this should
+ * be done only after qcow2_check_refcounts() made sure the refcount
+ * structures are valid.
+ * (In the meantime, the image is still valid because
+ * qcow2_check_refcounts() does not do anything with snapshots'
+ * extra data.)
+ */
+static int qcow2_do_read_snapshots(BlockDriverState *bs, bool repair,
+ int *nb_clusters_reduced,
+ int *extra_data_dropped,
+ Error **errp)
{
BDRVQcow2State *s = bs->opaque;
QCowSnapshotHeader h;
QCowSnapshotExtraData extra;
QCowSnapshot *sn;
int i, id_str_size, name_size;
- int64_t offset;
- uint32_t extra_data_size;
+ int64_t offset, pre_sn_offset;
+ uint64_t table_length = 0;
int ret;
if (!s->nb_snapshots) {
s->snapshots = g_new0(QCowSnapshot, s->nb_snapshots);
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 */
offset = ROUND_UP(offset, 8);
ret = bdrv_pread(bs->file, offset, &h, sizeof(h));
if (ret < 0) {
+ error_setg_errno(errp, -ret, "Failed to read snapshot table");
goto fail;
}
sn->date_sec = be32_to_cpu(h.date_sec);
sn->date_nsec = be32_to_cpu(h.date_nsec);
sn->vm_clock_nsec = be64_to_cpu(h.vm_clock_nsec);
- extra_data_size = be32_to_cpu(h.extra_data_size);
+ sn->extra_data_size = be32_to_cpu(h.extra_data_size);
id_str_size = be16_to_cpu(h.id_str_size);
name_size = be16_to_cpu(h.name_size);
- /* Read extra data */
+ if (sn->extra_data_size > QCOW_MAX_SNAPSHOT_EXTRA_DATA) {
+ if (!repair) {
+ ret = -EFBIG;
+ error_setg(errp, "Too much extra metadata in snapshot table "
+ "entry %i", i);
+ error_append_hint(errp, "You can force-remove this extra "
+ "metadata with qemu-img check -r all\n");
+ goto fail;
+ }
+
+ fprintf(stderr, "Discarding too much extra metadata in snapshot "
+ "table entry %i (%" PRIu32 " > %u)\n",
+ i, sn->extra_data_size, QCOW_MAX_SNAPSHOT_EXTRA_DATA);
+
+ (*extra_data_dropped)++;
+ truncate_unknown_extra_data = true;
+ }
+
+ /* Read known extra data */
ret = bdrv_pread(bs->file, offset, &extra,
- MIN(sizeof(extra), extra_data_size));
+ MIN(sizeof(extra), sn->extra_data_size));
if (ret < 0) {
+ error_setg_errno(errp, -ret, "Failed to read snapshot table");
goto fail;
}
- offset += extra_data_size;
+ offset += MIN(sizeof(extra), sn->extra_data_size);
- if (extra_data_size >= 8) {
+ if (sn->extra_data_size >= endof(QCowSnapshotExtraData,
+ vm_state_size_large)) {
sn->vm_state_size = be64_to_cpu(extra.vm_state_size_large);
}
- if (extra_data_size >= 16) {
+ if (sn->extra_data_size >= endof(QCowSnapshotExtraData, disk_size)) {
sn->disk_size = be64_to_cpu(extra.disk_size);
} else {
sn->disk_size = bs->total_sectors * BDRV_SECTOR_SIZE;
}
+ if (sn->extra_data_size >= endof(QCowSnapshotExtraData, icount)) {
+ sn->icount = be64_to_cpu(extra.icount);
+ } else {
+ sn->icount = -1ULL;
+ }
+
+ if (sn->extra_data_size > sizeof(extra)) {
+ uint64_t extra_data_end;
+ size_t unknown_extra_data_size;
+
+ extra_data_end = offset + sn->extra_data_size - sizeof(extra);
+
+ if (truncate_unknown_extra_data) {
+ sn->extra_data_size = QCOW_MAX_SNAPSHOT_EXTRA_DATA;
+ }
+
+ /* Store unknown extra data */
+ unknown_extra_data_size = sn->extra_data_size - sizeof(extra);
+ sn->unknown_extra_data = g_malloc(unknown_extra_data_size);
+ ret = bdrv_pread(bs->file, offset, sn->unknown_extra_data,
+ unknown_extra_data_size);
+ if (ret < 0) {
+ error_setg_errno(errp, -ret,
+ "Failed to read snapshot table");
+ goto fail;
+ }
+ offset = extra_data_end;
+ }
+
/* Read snapshot ID */
sn->id_str = g_malloc(id_str_size + 1);
ret = bdrv_pread(bs->file, offset, sn->id_str, id_str_size);
if (ret < 0) {
+ error_setg_errno(errp, -ret, "Failed to read snapshot table");
goto fail;
}
offset += id_str_size;
sn->name = g_malloc(name_size + 1);
ret = bdrv_pread(bs->file, offset, sn->name, name_size);
if (ret < 0) {
+ error_setg_errno(errp, -ret, "Failed to read snapshot table");
goto fail;
}
offset += name_size;
sn->name[name_size] = '\0';
- if (offset - s->snapshots_offset > QCOW_MAX_SNAPSHOTS_SIZE) {
- ret = -EFBIG;
- goto fail;
+ /* Note that the extra data may have been truncated */
+ table_length += sizeof(h) + sn->extra_data_size + id_str_size +
+ name_size;
+ if (!repair) {
+ assert(table_length == offset - s->snapshots_offset);
+ }
+
+ if (table_length > QCOW_MAX_SNAPSHOTS_SIZE ||
+ offset - s->snapshots_offset > INT_MAX)
+ {
+ 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;
}
}
return ret;
}
+int qcow2_read_snapshots(BlockDriverState *bs, Error **errp)
+{
+ return qcow2_do_read_snapshots(bs, false, NULL, NULL, errp);
+}
+
/* add at the end of the file a new list of snapshots */
-static int qcow2_write_snapshots(BlockDriverState *bs)
+int qcow2_write_snapshots(BlockDriverState *bs)
{
BDRVQcow2State *s = bs->opaque;
QCowSnapshot *sn;
sn = s->snapshots + i;
offset = ROUND_UP(offset, 8);
offset += sizeof(h);
- offset += sizeof(extra);
+ offset += MAX(sizeof(extra), sn->extra_data_size);
offset += strlen(sn->id_str);
offset += strlen(sn->name);
/* The snapshot list position has not yet been updated, so these clusters
* must indeed be completely free */
- ret = qcow2_pre_write_overlap_check(bs, 0, offset, snapshots_size);
+ ret = qcow2_pre_write_overlap_check(bs, 0, offset, snapshots_size, false);
if (ret < 0) {
goto fail;
}
h.date_sec = cpu_to_be32(sn->date_sec);
h.date_nsec = cpu_to_be32(sn->date_nsec);
h.vm_clock_nsec = cpu_to_be64(sn->vm_clock_nsec);
- h.extra_data_size = cpu_to_be32(sizeof(extra));
+ h.extra_data_size = cpu_to_be32(MAX(sizeof(extra),
+ sn->extra_data_size));
memset(&extra, 0, sizeof(extra));
extra.vm_state_size_large = cpu_to_be64(sn->vm_state_size);
extra.disk_size = cpu_to_be64(sn->disk_size);
+ extra.icount = cpu_to_be64(sn->icount);
id_str_size = strlen(sn->id_str);
name_size = strlen(sn->name);
}
offset += sizeof(extra);
+ if (sn->extra_data_size > sizeof(extra)) {
+ size_t unknown_extra_data_size =
+ sn->extra_data_size - sizeof(extra);
+
+ /* qcow2_read_snapshots() ensures no unbounded allocation */
+ assert(unknown_extra_data_size <= BDRV_REQUEST_MAX_BYTES);
+ assert(sn->unknown_extra_data);
+
+ ret = bdrv_pwrite(bs->file, offset, sn->unknown_extra_data,
+ unknown_extra_data_size);
+ if (ret < 0) {
+ goto fail;
+ }
+ offset += unknown_extra_data_size;
+ }
+
ret = bdrv_pwrite(bs->file, offset, sn->id_str, id_str_size);
if (ret < 0) {
goto fail;
}
QEMU_BUILD_BUG_ON(offsetof(QCowHeader, snapshots_offset) !=
- offsetof(QCowHeader, nb_snapshots) + sizeof(header_data.nb_snapshots));
+ endof(QCowHeader, nb_snapshots));
header_data.nb_snapshots = cpu_to_be32(s->nb_snapshots);
header_data.snapshots_offset = cpu_to_be64(snapshots_offset);
return ret;
}
+int coroutine_fn qcow2_check_read_snapshot_table(BlockDriverState *bs,
+ BdrvCheckResult *result,
+ BdrvCheckMode fix)
+{
+ BDRVQcow2State *s = bs->opaque;
+ Error *local_err = NULL;
+ int nb_clusters_reduced = 0;
+ int extra_data_dropped = 0;
+ int ret;
+ struct {
+ uint32_t nb_snapshots;
+ uint64_t snapshots_offset;
+ } QEMU_PACKED snapshot_table_pointer;
+
+ /* qcow2_do_open() discards this information in check mode */
+ ret = bdrv_pread(bs->file, offsetof(QCowHeader, nb_snapshots),
+ &snapshot_table_pointer, sizeof(snapshot_table_pointer));
+ if (ret < 0) {
+ result->check_errors++;
+ fprintf(stderr, "ERROR failed to read the snapshot table pointer from "
+ "the image header: %s\n", strerror(-ret));
+ return ret;
+ }
+
+ 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,
+ "snapshot table", &local_err);
+ if (ret < 0) {
+ 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;
+
+ return ret;
+ }
+
+ qemu_co_mutex_unlock(&s->lock);
+ ret = qcow2_do_read_snapshots(bs, fix & BDRV_FIX_ERRORS,
+ &nb_clusters_reduced, &extra_data_dropped,
+ &local_err);
+ qemu_co_mutex_lock(&s->lock);
+ if (ret < 0) {
+ result->check_errors++;
+ error_reportf_err(local_err,
+ "ERROR failed to read the snapshot table: ");
+
+ /* We did not read the snapshot table, so invalidate this information */
+ s->snapshots_offset = 0;
+ s->nb_snapshots = 0;
+
+ return ret;
+ }
+ 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;
+}
+
+int coroutine_fn qcow2_check_fix_snapshot_table(BlockDriverState *bs,
+ BdrvCheckResult *result,
+ BdrvCheckMode fix)
+{
+ BDRVQcow2State *s = bs->opaque;
+ int ret;
+
+ if (result->corruptions && (fix & BDRV_FIX_ERRORS)) {
+ qemu_co_mutex_unlock(&s->lock);
+ ret = qcow2_write_snapshots(bs);
+ qemu_co_mutex_lock(&s->lock);
+ if (ret < 0) {
+ result->check_errors++;
+ fprintf(stderr, "ERROR failed to update snapshot table: %s\n",
+ strerror(-ret));
+ return ret;
+ }
+
+ result->corruptions_fixed += result->corruptions;
+ result->corruptions = 0;
+ }
+
+ return 0;
+}
+
static void find_new_snapshot_id(BlockDriverState *bs,
char *id_str, int id_str_size)
{
return -EFBIG;
}
+ if (has_data_file(bs)) {
+ return -ENOTSUP;
+ }
+
memset(sn, 0, sizeof(*sn));
/* Generate an ID */
sn->date_sec = sn_info->date_sec;
sn->date_nsec = sn_info->date_nsec;
sn->vm_clock_nsec = sn_info->vm_clock_nsec;
+ sn->icount = sn_info->icount;
+ sn->extra_data_size = sizeof(QCowSnapshotExtraData);
/* 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));
+ l1_table_offset = qcow2_alloc_clusters(bs, s->l1_size * L1E_SIZE);
if (l1_table_offset < 0) {
ret = l1_table_offset;
goto fail;
}
ret = qcow2_pre_write_overlap_check(bs, 0, sn->l1_table_offset,
- s->l1_size * sizeof(uint64_t));
+ s->l1_size * L1E_SIZE, false);
if (ret < 0) {
goto fail;
}
ret = bdrv_pwrite(bs->file, sn->l1_table_offset, l1_table,
- s->l1_size * sizeof(uint64_t));
+ s->l1_size * L1E_SIZE);
if (ret < 0) {
goto fail;
}
int ret;
uint64_t *sn_l1_table = NULL;
+ if (has_data_file(bs)) {
+ return -ENOTSUP;
+ }
+
/* Search the snapshot */
snapshot_index = find_snapshot_by_id_or_name(bs, snapshot_id);
if (snapshot_index < 0) {
sn = &s->snapshots[snapshot_index];
ret = qcow2_validate_table(bs, sn->l1_table_offset, sn->l1_size,
- sizeof(uint64_t), QCOW_MAX_L1_SIZE,
+ L1E_SIZE, QCOW_MAX_L1_SIZE,
"Snapshot L1 table", &local_err);
if (ret < 0) {
error_report_err(local_err);
}
if (sn->disk_size != bs->total_sectors * BDRV_SECTOR_SIZE) {
- error_report("qcow2: Loading snapshots with different disk "
- "size is not implemented");
- ret = -ENOTSUP;
- goto fail;
+ BlockBackend *blk = blk_new_with_bs(bs, BLK_PERM_RESIZE, BLK_PERM_ALL,
+ &local_err);
+ if (!blk) {
+ error_report_err(local_err);
+ ret = -ENOTSUP;
+ goto fail;
+ }
+
+ ret = blk_truncate(blk, sn->disk_size, true, PREALLOC_MODE_OFF, 0,
+ &local_err);
+ blk_unref(blk);
+ if (ret < 0) {
+ error_report_err(local_err);
+ goto fail;
+ }
}
/*
goto fail;
}
- cur_l1_bytes = s->l1_size * sizeof(uint64_t);
- sn_l1_bytes = sn->l1_size * sizeof(uint64_t);
+ cur_l1_bytes = s->l1_size * L1E_SIZE;
+ sn_l1_bytes = sn->l1_size * L1E_SIZE;
/*
* Copy the snapshot L1 table to the current L1 table.
}
ret = qcow2_pre_write_overlap_check(bs, QCOW2_OL_ACTIVE_L1,
- s->l1_table_offset, cur_l1_bytes);
+ s->l1_table_offset, cur_l1_bytes,
+ false);
if (ret < 0) {
goto fail;
}
QCowSnapshot sn;
int snapshot_index, ret;
+ if (has_data_file(bs)) {
+ return -ENOTSUP;
+ }
+
/* Search the snapshot */
snapshot_index = find_snapshot_by_id_and_name(bs, snapshot_id, name);
if (snapshot_index < 0) {
sn = s->snapshots[snapshot_index];
ret = qcow2_validate_table(bs, sn.l1_table_offset, sn.l1_size,
- sizeof(uint64_t), QCOW_MAX_L1_SIZE,
+ L1E_SIZE, QCOW_MAX_L1_SIZE,
"Snapshot L1 table", errp);
if (ret < 0) {
return ret;
* The snapshot is now unused, clean up. If we fail after this point, we
* won't recover but just leak clusters.
*/
+ g_free(sn.unknown_extra_data);
g_free(sn.id_str);
g_free(sn.name);
error_setg_errno(errp, -ret, "Failed to free the cluster and L1 table");
return ret;
}
- qcow2_free_clusters(bs, sn.l1_table_offset, sn.l1_size * sizeof(uint64_t),
+ qcow2_free_clusters(bs, sn.l1_table_offset, sn.l1_size * L1E_SIZE,
QCOW2_DISCARD_SNAPSHOT);
/* must update the copied flag on the current cluster offsets */
QCowSnapshot *sn;
int i;
+ if (has_data_file(bs)) {
+ return -ENOTSUP;
+ }
if (!s->nb_snapshots) {
*psn_tab = NULL;
return s->nb_snapshots;
sn_info->date_sec = sn->date_sec;
sn_info->date_nsec = sn->date_nsec;
sn_info->vm_clock_nsec = sn->vm_clock_nsec;
+ sn_info->icount = sn->icount;
}
*psn_tab = sn_tab;
return s->nb_snapshots;
int new_l1_bytes;
int ret;
- assert(bs->read_only);
+ assert(bdrv_is_read_only(bs));
/* Search the snapshot */
snapshot_index = find_snapshot_by_id_and_name(bs, snapshot_id, name);
/* Allocate and read in the snapshot's L1 table */
ret = qcow2_validate_table(bs, sn->l1_table_offset, sn->l1_size,
- sizeof(uint64_t), QCOW_MAX_L1_SIZE,
+ L1E_SIZE, QCOW_MAX_L1_SIZE,
"Snapshot L1 table", errp);
if (ret < 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_bytes = sn->l1_size * L1E_SIZE;
+ new_l1_table = qemu_try_blockalign(bs->file->bs, new_l1_bytes);
if (new_l1_table == NULL) {
return -ENOMEM;
}
projects / qemu.git / blobdiff