qcow2: Employ metadata overlap checks
The pre-write overlap check function is now called before most of the qcow2 writes (aborting it on collision or other error). Signed-off-by: Max Reitz <mreitz@redhat.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com>
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@ -114,6 +114,23 @@ static int qcow2_cache_entry_flush(BlockDriverState *bs, Qcow2Cache *c, int i)
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return ret;
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}
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if (c == s->refcount_block_cache) {
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ret = qcow2_pre_write_overlap_check(bs,
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QCOW2_OL_DEFAULT & ~QCOW2_OL_REFCOUNT_BLOCK,
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c->entries[i].offset, s->cluster_size);
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} else if (c == s->l2_table_cache) {
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ret = qcow2_pre_write_overlap_check(bs,
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QCOW2_OL_DEFAULT & ~QCOW2_OL_ACTIVE_L2,
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c->entries[i].offset, s->cluster_size);
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} else {
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ret = qcow2_pre_write_overlap_check(bs, QCOW2_OL_DEFAULT,
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c->entries[i].offset, s->cluster_size);
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}
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if (ret < 0) {
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return ret;
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}
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if (c == s->refcount_block_cache) {
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BLKDBG_EVENT(bs->file, BLKDBG_REFBLOCK_UPDATE_PART);
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} else if (c == s->l2_table_cache) {
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@ -80,6 +80,14 @@ int qcow2_grow_l1_table(BlockDriverState *bs, uint64_t min_size,
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goto fail;
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}
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/* the L1 position has not yet been updated, so these clusters must
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* indeed be completely free */
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ret = qcow2_pre_write_overlap_check(bs, QCOW2_OL_DEFAULT,
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new_l1_table_offset, new_l1_size2);
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if (ret < 0) {
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goto fail;
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}
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BLKDBG_EVENT(bs->file, BLKDBG_L1_GROW_WRITE_TABLE);
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for(i = 0; i < s->l1_size; i++)
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new_l1_table[i] = cpu_to_be64(new_l1_table[i]);
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@ -149,6 +157,13 @@ static int write_l1_entry(BlockDriverState *bs, int l1_index)
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buf[i] = cpu_to_be64(s->l1_table[l1_start_index + i]);
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}
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ret = qcow2_pre_write_overlap_check(bs,
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QCOW2_OL_DEFAULT & ~QCOW2_OL_ACTIVE_L1,
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s->l1_table_offset + 8 * l1_start_index, sizeof(buf));
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if (ret < 0) {
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return ret;
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}
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BLKDBG_EVENT(bs->file, BLKDBG_L1_UPDATE);
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ret = bdrv_pwrite_sync(bs->file, s->l1_table_offset + 8 * l1_start_index,
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buf, sizeof(buf));
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@ -368,6 +383,12 @@ static int coroutine_fn copy_sectors(BlockDriverState *bs,
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&s->aes_encrypt_key);
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}
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ret = qcow2_pre_write_overlap_check(bs, QCOW2_OL_DEFAULT,
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cluster_offset + n_start * BDRV_SECTOR_SIZE, n * BDRV_SECTOR_SIZE);
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if (ret < 0) {
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goto out;
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}
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BLKDBG_EVENT(bs->file, BLKDBG_COW_WRITE);
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ret = bdrv_co_writev(bs->file, (cluster_offset >> 9) + n_start, n, &qiov);
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if (ret < 0) {
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@ -189,6 +189,15 @@ static int qcow2_write_snapshots(BlockDriverState *bs)
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return ret;
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}
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/* The snapshot list position has not yet been updated, so these clusters
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* must indeed be completely free */
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ret = qcow2_pre_write_overlap_check(bs, QCOW2_OL_DEFAULT, offset,
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s->snapshots_size);
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if (ret < 0) {
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return ret;
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}
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/* Write all snapshots to the new list */
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for(i = 0; i < s->nb_snapshots; i++) {
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sn = s->snapshots + i;
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@ -363,6 +372,12 @@ int qcow2_snapshot_create(BlockDriverState *bs, QEMUSnapshotInfo *sn_info)
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l1_table[i] = cpu_to_be64(s->l1_table[i]);
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}
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ret = qcow2_pre_write_overlap_check(bs, QCOW2_OL_DEFAULT,
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sn->l1_table_offset, s->l1_size * sizeof(uint64_t));
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if (ret < 0) {
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goto fail;
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}
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ret = bdrv_pwrite(bs->file, sn->l1_table_offset, l1_table,
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s->l1_size * sizeof(uint64_t));
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if (ret < 0) {
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@ -475,6 +490,13 @@ int qcow2_snapshot_goto(BlockDriverState *bs, const char *snapshot_id)
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goto fail;
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}
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ret = qcow2_pre_write_overlap_check(bs,
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QCOW2_OL_DEFAULT & ~QCOW2_OL_ACTIVE_L1,
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s->l1_table_offset, cur_l1_bytes);
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if (ret < 0) {
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goto fail;
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}
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ret = bdrv_pwrite_sync(bs->file, s->l1_table_offset, sn_l1_table,
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cur_l1_bytes);
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if (ret < 0) {
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@ -624,6 +624,8 @@ static int qcow2_open(BlockDriverState *bs, QDict *options, int flags)
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qcow2_free_snapshots(bs);
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qcow2_refcount_close(bs);
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g_free(s->l1_table);
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/* else pre-write overlap checks in cache_destroy may crash */
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s->l1_table = NULL;
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if (s->l2_table_cache) {
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qcow2_cache_destroy(bs, s->l2_table_cache);
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}
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@ -923,6 +925,13 @@ static coroutine_fn int qcow2_co_writev(BlockDriverState *bs,
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cur_nr_sectors * 512);
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}
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ret = qcow2_pre_write_overlap_check(bs, QCOW2_OL_DEFAULT,
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cluster_offset + index_in_cluster * BDRV_SECTOR_SIZE,
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cur_nr_sectors * BDRV_SECTOR_SIZE);
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if (ret < 0) {
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goto fail;
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}
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qemu_co_mutex_unlock(&s->lock);
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BLKDBG_EVENT(bs->file, BLKDBG_WRITE_AIO);
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trace_qcow2_writev_data(qemu_coroutine_self(),
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@ -989,6 +998,8 @@ static void qcow2_close(BlockDriverState *bs)
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{
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BDRVQcowState *s = bs->opaque;
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g_free(s->l1_table);
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/* else pre-write overlap checks in cache_destroy may crash */
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s->l1_table = NULL;
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qcow2_cache_flush(bs, s->l2_table_cache);
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qcow2_cache_flush(bs, s->refcount_block_cache);
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@ -1668,6 +1679,14 @@ static int qcow2_write_compressed(BlockDriverState *bs, int64_t sector_num,
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if (ret != Z_STREAM_END || out_len >= s->cluster_size) {
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/* could not compress: write normal cluster */
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ret = qcow2_pre_write_overlap_check(bs, QCOW2_OL_DEFAULT,
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sector_num * BDRV_SECTOR_SIZE,
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s->cluster_sectors * BDRV_SECTOR_SIZE);
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if (ret < 0) {
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goto fail;
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}
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ret = bdrv_write(bs, sector_num, buf, s->cluster_sectors);
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if (ret < 0) {
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goto fail;
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@ -1680,6 +1699,13 @@ static int qcow2_write_compressed(BlockDriverState *bs, int64_t sector_num,
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goto fail;
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}
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cluster_offset &= s->cluster_offset_mask;
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ret = qcow2_pre_write_overlap_check(bs, QCOW2_OL_DEFAULT,
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cluster_offset, out_len);
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if (ret < 0) {
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goto fail;
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}
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BLKDBG_EVENT(bs->file, BLKDBG_WRITE_COMPRESSED);
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ret = bdrv_pwrite(bs->file, cluster_offset, out_buf, out_len);
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if (ret < 0) {
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