1074 lines
34 KiB
C
1074 lines
34 KiB
C
/*
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* Block driver for the QCOW version 2 format
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*
|
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* Copyright (c) 2004-2006 Fabrice Bellard
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*
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* Permission is hereby granted, free of charge, to any person obtaining a copy
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* of this software and associated documentation files (the "Software"), to deal
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* in the Software without restriction, including without limitation the rights
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* to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
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* copies of the Software, and to permit persons to whom the Software is
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* furnished to do so, subject to the following conditions:
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*
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* The above copyright notice and this permission notice shall be included in
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* all copies or substantial portions of the Software.
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*
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* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
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* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
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* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
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* THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
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* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
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* OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
|
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* THE SOFTWARE.
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*/
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#include "qemu/osdep.h"
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#include "sysemu/block-backend.h"
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#include "qapi/error.h"
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#include "qcow2.h"
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#include "qemu/bswap.h"
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#include "qemu/error-report.h"
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#include "qemu/cutils.h"
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static void qcow2_free_single_snapshot(BlockDriverState *bs, int i)
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|
{
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BDRVQcow2State *s = bs->opaque;
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assert(i >= 0 && i < s->nb_snapshots);
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g_free(s->snapshots[i].name);
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g_free(s->snapshots[i].id_str);
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g_free(s->snapshots[i].unknown_extra_data);
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memset(&s->snapshots[i], 0, sizeof(s->snapshots[i]));
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}
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void qcow2_free_snapshots(BlockDriverState *bs)
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{
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BDRVQcow2State *s = bs->opaque;
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int i;
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for(i = 0; i < s->nb_snapshots; i++) {
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qcow2_free_single_snapshot(bs, i);
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}
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g_free(s->snapshots);
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s->snapshots = NULL;
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s->nb_snapshots = 0;
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}
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/*
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* If @repair is true, try to repair a broken snapshot table instead
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* of just returning an error:
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*
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* - If the snapshot table was too long, set *nb_clusters_reduced to
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* the number of snapshots removed off the end.
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* The caller will update the on-disk nb_snapshots accordingly;
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* this leaks clusters, but is safe.
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* (The on-disk information must be updated before
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* qcow2_check_refcounts(), because that function relies on
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* s->nb_snapshots to reflect the on-disk value.)
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*
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* - If there were snapshots with too much extra metadata, increment
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* *extra_data_dropped for each.
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* This requires the caller to eventually rewrite the whole snapshot
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* table, which requires cluster allocation. Therefore, this should
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* be done only after qcow2_check_refcounts() made sure the refcount
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* structures are valid.
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* (In the meantime, the image is still valid because
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* qcow2_check_refcounts() does not do anything with snapshots'
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* extra data.)
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*/
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static int qcow2_do_read_snapshots(BlockDriverState *bs, bool repair,
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int *nb_clusters_reduced,
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int *extra_data_dropped,
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Error **errp)
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{
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BDRVQcow2State *s = bs->opaque;
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QCowSnapshotHeader h;
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QCowSnapshotExtraData extra;
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QCowSnapshot *sn;
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int i, id_str_size, name_size;
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int64_t offset, pre_sn_offset;
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uint64_t table_length = 0;
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int ret;
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if (!s->nb_snapshots) {
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s->snapshots = NULL;
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s->snapshots_size = 0;
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return 0;
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}
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offset = s->snapshots_offset;
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s->snapshots = g_new0(QCowSnapshot, s->nb_snapshots);
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for(i = 0; i < s->nb_snapshots; i++) {
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bool truncate_unknown_extra_data = false;
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pre_sn_offset = offset;
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table_length = ROUND_UP(table_length, 8);
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/* Read statically sized part of the snapshot header */
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offset = ROUND_UP(offset, 8);
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ret = bdrv_pread(bs->file, offset, &h, sizeof(h));
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if (ret < 0) {
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error_setg_errno(errp, -ret, "Failed to read snapshot table");
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goto fail;
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}
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offset += sizeof(h);
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sn = s->snapshots + i;
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sn->l1_table_offset = be64_to_cpu(h.l1_table_offset);
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sn->l1_size = be32_to_cpu(h.l1_size);
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sn->vm_state_size = be32_to_cpu(h.vm_state_size);
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sn->date_sec = be32_to_cpu(h.date_sec);
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sn->date_nsec = be32_to_cpu(h.date_nsec);
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sn->vm_clock_nsec = be64_to_cpu(h.vm_clock_nsec);
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sn->extra_data_size = be32_to_cpu(h.extra_data_size);
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id_str_size = be16_to_cpu(h.id_str_size);
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name_size = be16_to_cpu(h.name_size);
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if (sn->extra_data_size > QCOW_MAX_SNAPSHOT_EXTRA_DATA) {
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if (!repair) {
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ret = -EFBIG;
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error_setg(errp, "Too much extra metadata in snapshot table "
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"entry %i", i);
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error_append_hint(errp, "You can force-remove this extra "
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"metadata with qemu-img check -r all\n");
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goto fail;
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}
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fprintf(stderr, "Discarding too much extra metadata in snapshot "
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"table entry %i (%" PRIu32 " > %u)\n",
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i, sn->extra_data_size, QCOW_MAX_SNAPSHOT_EXTRA_DATA);
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(*extra_data_dropped)++;
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truncate_unknown_extra_data = true;
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}
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/* Read known extra data */
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ret = bdrv_pread(bs->file, offset, &extra,
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MIN(sizeof(extra), sn->extra_data_size));
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if (ret < 0) {
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error_setg_errno(errp, -ret, "Failed to read snapshot table");
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goto fail;
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}
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offset += MIN(sizeof(extra), sn->extra_data_size);
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if (sn->extra_data_size >= endof(QCowSnapshotExtraData,
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vm_state_size_large)) {
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sn->vm_state_size = be64_to_cpu(extra.vm_state_size_large);
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}
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if (sn->extra_data_size >= endof(QCowSnapshotExtraData, disk_size)) {
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sn->disk_size = be64_to_cpu(extra.disk_size);
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} else {
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sn->disk_size = bs->total_sectors * BDRV_SECTOR_SIZE;
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}
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if (sn->extra_data_size >= endof(QCowSnapshotExtraData, icount)) {
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sn->icount = be64_to_cpu(extra.icount);
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} else {
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sn->icount = -1ULL;
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}
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if (sn->extra_data_size > sizeof(extra)) {
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uint64_t extra_data_end;
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size_t unknown_extra_data_size;
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extra_data_end = offset + sn->extra_data_size - sizeof(extra);
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if (truncate_unknown_extra_data) {
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sn->extra_data_size = QCOW_MAX_SNAPSHOT_EXTRA_DATA;
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}
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/* Store unknown extra data */
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unknown_extra_data_size = sn->extra_data_size - sizeof(extra);
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sn->unknown_extra_data = g_malloc(unknown_extra_data_size);
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ret = bdrv_pread(bs->file, offset, sn->unknown_extra_data,
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unknown_extra_data_size);
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if (ret < 0) {
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error_setg_errno(errp, -ret,
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"Failed to read snapshot table");
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goto fail;
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}
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offset = extra_data_end;
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}
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/* Read snapshot ID */
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sn->id_str = g_malloc(id_str_size + 1);
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ret = bdrv_pread(bs->file, offset, sn->id_str, id_str_size);
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if (ret < 0) {
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error_setg_errno(errp, -ret, "Failed to read snapshot table");
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goto fail;
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}
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offset += id_str_size;
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sn->id_str[id_str_size] = '\0';
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/* Read snapshot name */
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sn->name = g_malloc(name_size + 1);
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ret = bdrv_pread(bs->file, offset, sn->name, name_size);
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if (ret < 0) {
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error_setg_errno(errp, -ret, "Failed to read snapshot table");
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goto fail;
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}
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offset += name_size;
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sn->name[name_size] = '\0';
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/* Note that the extra data may have been truncated */
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table_length += sizeof(h) + sn->extra_data_size + id_str_size +
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name_size;
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if (!repair) {
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assert(table_length == offset - s->snapshots_offset);
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}
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if (table_length > QCOW_MAX_SNAPSHOTS_SIZE ||
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offset - s->snapshots_offset > INT_MAX)
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{
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if (!repair) {
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ret = -EFBIG;
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error_setg(errp, "Snapshot table is too big");
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error_append_hint(errp, "You can force-remove all %u "
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"overhanging snapshots with qemu-img check "
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"-r all\n", s->nb_snapshots - i);
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goto fail;
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}
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fprintf(stderr, "Discarding %u overhanging snapshots (snapshot "
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"table is too big)\n", s->nb_snapshots - i);
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*nb_clusters_reduced += (s->nb_snapshots - i);
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/* Discard current snapshot also */
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qcow2_free_single_snapshot(bs, i);
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/*
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* This leaks all the rest of the snapshot table and the
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* snapshots' clusters, but we run in check -r all mode,
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* so qcow2_check_refcounts() will take care of it.
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*/
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s->nb_snapshots = i;
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offset = pre_sn_offset;
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break;
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}
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}
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assert(offset - s->snapshots_offset <= INT_MAX);
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s->snapshots_size = offset - s->snapshots_offset;
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return 0;
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fail:
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qcow2_free_snapshots(bs);
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return ret;
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}
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int qcow2_read_snapshots(BlockDriverState *bs, Error **errp)
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{
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return qcow2_do_read_snapshots(bs, false, NULL, NULL, errp);
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}
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/* add at the end of the file a new list of snapshots */
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int qcow2_write_snapshots(BlockDriverState *bs)
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{
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BDRVQcow2State *s = bs->opaque;
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QCowSnapshot *sn;
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QCowSnapshotHeader h;
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QCowSnapshotExtraData extra;
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int i, name_size, id_str_size, snapshots_size;
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struct {
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uint32_t nb_snapshots;
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uint64_t snapshots_offset;
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} QEMU_PACKED header_data;
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int64_t offset, snapshots_offset = 0;
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int ret;
|
|
|
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/* compute the size of the snapshots */
|
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offset = 0;
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for(i = 0; i < s->nb_snapshots; i++) {
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sn = s->snapshots + i;
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offset = ROUND_UP(offset, 8);
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offset += sizeof(h);
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offset += MAX(sizeof(extra), sn->extra_data_size);
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offset += strlen(sn->id_str);
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offset += strlen(sn->name);
|
|
|
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if (offset > QCOW_MAX_SNAPSHOTS_SIZE) {
|
|
ret = -EFBIG;
|
|
goto fail;
|
|
}
|
|
}
|
|
|
|
assert(offset <= INT_MAX);
|
|
snapshots_size = offset;
|
|
|
|
/* Allocate space for the new snapshot list */
|
|
snapshots_offset = qcow2_alloc_clusters(bs, snapshots_size);
|
|
offset = snapshots_offset;
|
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if (offset < 0) {
|
|
ret = offset;
|
|
goto fail;
|
|
}
|
|
ret = bdrv_flush(bs);
|
|
if (ret < 0) {
|
|
goto fail;
|
|
}
|
|
|
|
/* 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, false);
|
|
if (ret < 0) {
|
|
goto fail;
|
|
}
|
|
|
|
|
|
/* Write all snapshots to the new list */
|
|
for(i = 0; i < s->nb_snapshots; i++) {
|
|
sn = s->snapshots + i;
|
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memset(&h, 0, sizeof(h));
|
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h.l1_table_offset = cpu_to_be64(sn->l1_table_offset);
|
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h.l1_size = cpu_to_be32(sn->l1_size);
|
|
/* If it doesn't fit in 32 bit, older implementations should treat it
|
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* as a disk-only snapshot rather than truncate the VM state */
|
|
if (sn->vm_state_size <= 0xffffffff) {
|
|
h.vm_state_size = cpu_to_be32(sn->vm_state_size);
|
|
}
|
|
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(MAX(sizeof(extra),
|
|
sn->extra_data_size));
|
|
|
|
memset(&extra, 0, sizeof(extra));
|
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extra.vm_state_size_large = cpu_to_be64(sn->vm_state_size);
|
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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);
|
|
assert(id_str_size <= UINT16_MAX && name_size <= UINT16_MAX);
|
|
h.id_str_size = cpu_to_be16(id_str_size);
|
|
h.name_size = cpu_to_be16(name_size);
|
|
offset = ROUND_UP(offset, 8);
|
|
|
|
ret = bdrv_pwrite(bs->file, offset, &h, sizeof(h));
|
|
if (ret < 0) {
|
|
goto fail;
|
|
}
|
|
offset += sizeof(h);
|
|
|
|
ret = bdrv_pwrite(bs->file, offset, &extra, sizeof(extra));
|
|
if (ret < 0) {
|
|
goto fail;
|
|
}
|
|
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;
|
|
}
|
|
offset += id_str_size;
|
|
|
|
ret = bdrv_pwrite(bs->file, offset, sn->name, name_size);
|
|
if (ret < 0) {
|
|
goto fail;
|
|
}
|
|
offset += name_size;
|
|
}
|
|
|
|
/*
|
|
* Update the header to point to the new snapshot table. This requires the
|
|
* new table and its refcounts to be stable on disk.
|
|
*/
|
|
ret = bdrv_flush(bs);
|
|
if (ret < 0) {
|
|
goto fail;
|
|
}
|
|
|
|
QEMU_BUILD_BUG_ON(offsetof(QCowHeader, snapshots_offset) !=
|
|
endof(QCowHeader, nb_snapshots));
|
|
|
|
header_data.nb_snapshots = cpu_to_be32(s->nb_snapshots);
|
|
header_data.snapshots_offset = cpu_to_be64(snapshots_offset);
|
|
|
|
ret = bdrv_pwrite_sync(bs->file, offsetof(QCowHeader, nb_snapshots),
|
|
&header_data, sizeof(header_data));
|
|
if (ret < 0) {
|
|
goto fail;
|
|
}
|
|
|
|
/* free the old snapshot table */
|
|
qcow2_free_clusters(bs, s->snapshots_offset, s->snapshots_size,
|
|
QCOW2_DISCARD_SNAPSHOT);
|
|
s->snapshots_offset = snapshots_offset;
|
|
s->snapshots_size = snapshots_size;
|
|
return 0;
|
|
|
|
fail:
|
|
if (snapshots_offset > 0) {
|
|
qcow2_free_clusters(bs, snapshots_offset, snapshots_size,
|
|
QCOW2_DISCARD_ALWAYS);
|
|
}
|
|
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)
|
|
{
|
|
BDRVQcow2State *s = bs->opaque;
|
|
QCowSnapshot *sn;
|
|
int i;
|
|
unsigned long id, id_max = 0;
|
|
|
|
for(i = 0; i < s->nb_snapshots; i++) {
|
|
sn = s->snapshots + i;
|
|
id = strtoul(sn->id_str, NULL, 10);
|
|
if (id > id_max)
|
|
id_max = id;
|
|
}
|
|
snprintf(id_str, id_str_size, "%lu", id_max + 1);
|
|
}
|
|
|
|
static int find_snapshot_by_id_and_name(BlockDriverState *bs,
|
|
const char *id,
|
|
const char *name)
|
|
{
|
|
BDRVQcow2State *s = bs->opaque;
|
|
int i;
|
|
|
|
if (id && name) {
|
|
for (i = 0; i < s->nb_snapshots; i++) {
|
|
if (!strcmp(s->snapshots[i].id_str, id) &&
|
|
!strcmp(s->snapshots[i].name, name)) {
|
|
return i;
|
|
}
|
|
}
|
|
} else if (id) {
|
|
for (i = 0; i < s->nb_snapshots; i++) {
|
|
if (!strcmp(s->snapshots[i].id_str, id)) {
|
|
return i;
|
|
}
|
|
}
|
|
} else if (name) {
|
|
for (i = 0; i < s->nb_snapshots; i++) {
|
|
if (!strcmp(s->snapshots[i].name, name)) {
|
|
return i;
|
|
}
|
|
}
|
|
}
|
|
|
|
return -1;
|
|
}
|
|
|
|
static int find_snapshot_by_id_or_name(BlockDriverState *bs,
|
|
const char *id_or_name)
|
|
{
|
|
int ret;
|
|
|
|
ret = find_snapshot_by_id_and_name(bs, id_or_name, NULL);
|
|
if (ret >= 0) {
|
|
return ret;
|
|
}
|
|
return find_snapshot_by_id_and_name(bs, NULL, id_or_name);
|
|
}
|
|
|
|
/* if no id is provided, a new one is constructed */
|
|
int qcow2_snapshot_create(BlockDriverState *bs, QEMUSnapshotInfo *sn_info)
|
|
{
|
|
BDRVQcow2State *s = bs->opaque;
|
|
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;
|
|
|
|
if (s->nb_snapshots >= QCOW_MAX_SNAPSHOTS) {
|
|
return -EFBIG;
|
|
}
|
|
|
|
if (has_data_file(bs)) {
|
|
return -ENOTSUP;
|
|
}
|
|
|
|
memset(sn, 0, sizeof(*sn));
|
|
|
|
/* Generate an ID */
|
|
find_new_snapshot_id(bs, sn_info->id_str, sizeof(sn_info->id_str));
|
|
|
|
/* Populate sn with passed data */
|
|
sn->id_str = g_strdup(sn_info->id_str);
|
|
sn->name = g_strdup(sn_info->name);
|
|
|
|
sn->disk_size = bs->total_sectors * BDRV_SECTOR_SIZE;
|
|
sn->vm_state_size = sn_info->vm_state_size;
|
|
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 * L1E_SIZE);
|
|
if (l1_table_offset < 0) {
|
|
ret = l1_table_offset;
|
|
goto fail;
|
|
}
|
|
|
|
sn->l1_table_offset = l1_table_offset;
|
|
sn->l1_size = s->l1_size;
|
|
|
|
l1_table = g_try_new(uint64_t, s->l1_size);
|
|
if (s->l1_size && l1_table == NULL) {
|
|
ret = -ENOMEM;
|
|
goto fail;
|
|
}
|
|
|
|
for(i = 0; i < s->l1_size; i++) {
|
|
l1_table[i] = cpu_to_be64(s->l1_table[i]);
|
|
}
|
|
|
|
ret = qcow2_pre_write_overlap_check(bs, 0, sn->l1_table_offset,
|
|
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 * L1E_SIZE);
|
|
if (ret < 0) {
|
|
goto fail;
|
|
}
|
|
|
|
g_free(l1_table);
|
|
l1_table = NULL;
|
|
|
|
/*
|
|
* 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;
|
|
}
|
|
|
|
/* Append the new snapshot to the snapshot list */
|
|
new_snapshot_list = g_new(QCowSnapshot, s->nb_snapshots + 1);
|
|
if (s->snapshots) {
|
|
memcpy(new_snapshot_list, s->snapshots,
|
|
s->nb_snapshots * sizeof(QCowSnapshot));
|
|
old_snapshot_list = s->snapshots;
|
|
}
|
|
s->snapshots = new_snapshot_list;
|
|
s->snapshots[s->nb_snapshots++] = *sn;
|
|
|
|
ret = qcow2_write_snapshots(bs);
|
|
if (ret < 0) {
|
|
g_free(s->snapshots);
|
|
s->snapshots = old_snapshot_list;
|
|
s->nb_snapshots--;
|
|
goto fail;
|
|
}
|
|
|
|
g_free(old_snapshot_list);
|
|
|
|
/* The VM state isn't needed any more in the active L1 table; in fact, it
|
|
* hurts by causing expensive COW for the next snapshot. */
|
|
qcow2_cluster_discard(bs, qcow2_vm_state_offset(s),
|
|
ROUND_UP(sn->vm_state_size, s->cluster_size),
|
|
QCOW2_DISCARD_NEVER, false);
|
|
|
|
#ifdef DEBUG_ALLOC
|
|
{
|
|
BdrvCheckResult result = {0};
|
|
qcow2_check_refcounts(bs, &result, 0);
|
|
}
|
|
#endif
|
|
return 0;
|
|
|
|
fail:
|
|
g_free(sn->id_str);
|
|
g_free(sn->name);
|
|
g_free(l1_table);
|
|
|
|
return ret;
|
|
}
|
|
|
|
/* copy the snapshot 'snapshot_name' into the current disk image */
|
|
int qcow2_snapshot_goto(BlockDriverState *bs, const char *snapshot_id)
|
|
{
|
|
BDRVQcow2State *s = bs->opaque;
|
|
QCowSnapshot *sn;
|
|
Error *local_err = NULL;
|
|
int i, snapshot_index;
|
|
int cur_l1_bytes, sn_l1_bytes;
|
|
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) {
|
|
return -ENOENT;
|
|
}
|
|
sn = &s->snapshots[snapshot_index];
|
|
|
|
ret = qcow2_validate_table(bs, sn->l1_table_offset, sn->l1_size,
|
|
L1E_SIZE, QCOW_MAX_L1_SIZE,
|
|
"Snapshot L1 table", &local_err);
|
|
if (ret < 0) {
|
|
error_report_err(local_err);
|
|
goto fail;
|
|
}
|
|
|
|
if (sn->disk_size != bs->total_sectors * BDRV_SECTOR_SIZE) {
|
|
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;
|
|
}
|
|
}
|
|
|
|
/*
|
|
* Make sure that the current L1 table is big enough to contain the whole
|
|
* L1 table of the snapshot. If the snapshot L1 table is smaller, the
|
|
* current one must be padded with zeros.
|
|
*/
|
|
ret = qcow2_grow_l1_table(bs, sn->l1_size, true);
|
|
if (ret < 0) {
|
|
goto fail;
|
|
}
|
|
|
|
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.
|
|
*
|
|
* Before overwriting the old current L1 table on disk, make sure to
|
|
* increase all refcounts for the clusters referenced by the new one.
|
|
* Decrease the refcount referenced by the old one only when the L1
|
|
* table is overwritten.
|
|
*/
|
|
sn_l1_table = g_try_malloc0(cur_l1_bytes);
|
|
if (cur_l1_bytes && sn_l1_table == NULL) {
|
|
ret = -ENOMEM;
|
|
goto fail;
|
|
}
|
|
|
|
ret = bdrv_pread(bs->file, sn->l1_table_offset,
|
|
sn_l1_table, sn_l1_bytes);
|
|
if (ret < 0) {
|
|
goto fail;
|
|
}
|
|
|
|
ret = qcow2_update_snapshot_refcount(bs, sn->l1_table_offset,
|
|
sn->l1_size, 1);
|
|
if (ret < 0) {
|
|
goto fail;
|
|
}
|
|
|
|
ret = qcow2_pre_write_overlap_check(bs, QCOW2_OL_ACTIVE_L1,
|
|
s->l1_table_offset, cur_l1_bytes,
|
|
false);
|
|
if (ret < 0) {
|
|
goto fail;
|
|
}
|
|
|
|
ret = bdrv_pwrite_sync(bs->file, s->l1_table_offset, sn_l1_table,
|
|
cur_l1_bytes);
|
|
if (ret < 0) {
|
|
goto fail;
|
|
}
|
|
|
|
/*
|
|
* Decrease refcount of clusters of current L1 table.
|
|
*
|
|
* At this point, the in-memory s->l1_table points to the old L1 table,
|
|
* whereas on disk we already have the new one.
|
|
*
|
|
* qcow2_update_snapshot_refcount special cases the current L1 table to use
|
|
* the in-memory data instead of really using the offset to load a new one,
|
|
* which is why this works.
|
|
*/
|
|
ret = qcow2_update_snapshot_refcount(bs, s->l1_table_offset,
|
|
s->l1_size, -1);
|
|
|
|
/*
|
|
* Now update the in-memory L1 table to be in sync with the on-disk one. We
|
|
* need to do this even if updating refcounts failed.
|
|
*/
|
|
for(i = 0;i < s->l1_size; i++) {
|
|
s->l1_table[i] = be64_to_cpu(sn_l1_table[i]);
|
|
}
|
|
|
|
if (ret < 0) {
|
|
goto fail;
|
|
}
|
|
|
|
g_free(sn_l1_table);
|
|
sn_l1_table = NULL;
|
|
|
|
/*
|
|
* Update QCOW_OFLAG_COPIED in the active L1 table (it may have changed
|
|
* when we decreased the refcount of the old snapshot.
|
|
*/
|
|
ret = qcow2_update_snapshot_refcount(bs, s->l1_table_offset, s->l1_size, 0);
|
|
if (ret < 0) {
|
|
goto fail;
|
|
}
|
|
|
|
#ifdef DEBUG_ALLOC
|
|
{
|
|
BdrvCheckResult result = {0};
|
|
qcow2_check_refcounts(bs, &result, 0);
|
|
}
|
|
#endif
|
|
return 0;
|
|
|
|
fail:
|
|
g_free(sn_l1_table);
|
|
return ret;
|
|
}
|
|
|
|
int qcow2_snapshot_delete(BlockDriverState *bs,
|
|
const char *snapshot_id,
|
|
const char *name,
|
|
Error **errp)
|
|
{
|
|
BDRVQcow2State *s = bs->opaque;
|
|
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) {
|
|
error_setg(errp, "Can't find the snapshot");
|
|
return -ENOENT;
|
|
}
|
|
sn = s->snapshots[snapshot_index];
|
|
|
|
ret = qcow2_validate_table(bs, sn.l1_table_offset, sn.l1_size,
|
|
L1E_SIZE, QCOW_MAX_L1_SIZE,
|
|
"Snapshot L1 table", errp);
|
|
if (ret < 0) {
|
|
return ret;
|
|
}
|
|
|
|
/* Remove it from the snapshot list */
|
|
memmove(s->snapshots + snapshot_index,
|
|
s->snapshots + snapshot_index + 1,
|
|
(s->nb_snapshots - snapshot_index - 1) * sizeof(sn));
|
|
s->nb_snapshots--;
|
|
ret = qcow2_write_snapshots(bs);
|
|
if (ret < 0) {
|
|
error_setg_errno(errp, -ret,
|
|
"Failed to remove snapshot from snapshot list");
|
|
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);
|
|
|
|
/*
|
|
* Now decrease the refcounts of clusters referenced by the snapshot and
|
|
* free the L1 table.
|
|
*/
|
|
ret = qcow2_update_snapshot_refcount(bs, sn.l1_table_offset,
|
|
sn.l1_size, -1);
|
|
if (ret < 0) {
|
|
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 * L1E_SIZE,
|
|
QCOW2_DISCARD_SNAPSHOT);
|
|
|
|
/* must update the copied flag on the current cluster offsets */
|
|
ret = qcow2_update_snapshot_refcount(bs, s->l1_table_offset, s->l1_size, 0);
|
|
if (ret < 0) {
|
|
error_setg_errno(errp, -ret,
|
|
"Failed to update snapshot status in disk");
|
|
return ret;
|
|
}
|
|
|
|
#ifdef DEBUG_ALLOC
|
|
{
|
|
BdrvCheckResult result = {0};
|
|
qcow2_check_refcounts(bs, &result, 0);
|
|
}
|
|
#endif
|
|
return 0;
|
|
}
|
|
|
|
int qcow2_snapshot_list(BlockDriverState *bs, QEMUSnapshotInfo **psn_tab)
|
|
{
|
|
BDRVQcow2State *s = bs->opaque;
|
|
QEMUSnapshotInfo *sn_tab, *sn_info;
|
|
QCowSnapshot *sn;
|
|
int i;
|
|
|
|
if (has_data_file(bs)) {
|
|
return -ENOTSUP;
|
|
}
|
|
if (!s->nb_snapshots) {
|
|
*psn_tab = NULL;
|
|
return s->nb_snapshots;
|
|
}
|
|
|
|
sn_tab = g_new0(QEMUSnapshotInfo, s->nb_snapshots);
|
|
for(i = 0; i < s->nb_snapshots; i++) {
|
|
sn_info = sn_tab + i;
|
|
sn = s->snapshots + i;
|
|
pstrcpy(sn_info->id_str, sizeof(sn_info->id_str),
|
|
sn->id_str);
|
|
pstrcpy(sn_info->name, sizeof(sn_info->name),
|
|
sn->name);
|
|
sn_info->vm_state_size = sn->vm_state_size;
|
|
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 qcow2_snapshot_load_tmp(BlockDriverState *bs,
|
|
const char *snapshot_id,
|
|
const char *name,
|
|
Error **errp)
|
|
{
|
|
int i, snapshot_index;
|
|
BDRVQcow2State *s = bs->opaque;
|
|
QCowSnapshot *sn;
|
|
uint64_t *new_l1_table;
|
|
int new_l1_bytes;
|
|
int ret;
|
|
|
|
assert(bs->read_only);
|
|
|
|
/* Search the snapshot */
|
|
snapshot_index = find_snapshot_by_id_and_name(bs, snapshot_id, name);
|
|
if (snapshot_index < 0) {
|
|
error_setg(errp,
|
|
"Can't find snapshot");
|
|
return -ENOENT;
|
|
}
|
|
sn = &s->snapshots[snapshot_index];
|
|
|
|
/* Allocate and read in the snapshot's L1 table */
|
|
ret = qcow2_validate_table(bs, sn->l1_table_offset, sn->l1_size,
|
|
L1E_SIZE, QCOW_MAX_L1_SIZE,
|
|
"Snapshot L1 table", errp);
|
|
if (ret < 0) {
|
|
return ret;
|
|
}
|
|
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;
|
|
}
|
|
|
|
ret = bdrv_pread(bs->file, sn->l1_table_offset,
|
|
new_l1_table, new_l1_bytes);
|
|
if (ret < 0) {
|
|
error_setg(errp, "Failed to read l1 table for snapshot");
|
|
qemu_vfree(new_l1_table);
|
|
return ret;
|
|
}
|
|
|
|
/* Switch the L1 table */
|
|
qemu_vfree(s->l1_table);
|
|
|
|
s->l1_size = sn->l1_size;
|
|
s->l1_table_offset = sn->l1_table_offset;
|
|
s->l1_table = new_l1_table;
|
|
|
|
for(i = 0;i < s->l1_size; i++) {
|
|
be64_to_cpus(&s->l1_table[i]);
|
|
}
|
|
|
|
return 0;
|
|
}
|