From: Alexander Ivanov <alexander.iva...@virtuozzo.com> There could be corruptions in the image file: two guest memory areas refer to the same host cluster.
If a duplicate offset is found fix it by copying the content of the referred cluster to a new allocated cluster and replace one of the two referring entries by the new cluster offset. Signed-off-by: Natalia Kuzmina <natalia.kuzm...@openvz.org> Signed-off-by: Alexander Ivanov <alexander.iva...@virtuozzo.com> --- block/parallels.c | 135 ++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 135 insertions(+) diff --git a/block/parallels.c b/block/parallels.c index a0eb7ec3c3..73264b4bd1 100644 --- a/block/parallels.c +++ b/block/parallels.c @@ -64,6 +64,11 @@ static QEnumLookup prealloc_mode_lookup = { #define PARALLELS_OPT_PREALLOC_MODE "prealloc-mode" #define PARALLELS_OPT_PREALLOC_SIZE "prealloc-size" +#define REVERSED_BAT_UNTOUCHED 0xFFFFFFFF + +#define HOST_CLUSTER_INDEX(s, off) \ + ((off - ((s->header->data_off) << BDRV_SECTOR_BITS)) / (s->cluster_size)) + static QemuOptsList parallels_runtime_opts = { .name = "parallels", .head = QTAILQ_HEAD_INITIALIZER(parallels_runtime_opts.head), @@ -559,6 +564,131 @@ static int check_leak(BlockDriverState *bs, return 0; } +static int check_duplicate(BlockDriverState *bs, + BdrvCheckResult *res, + BdrvCheckMode fix) +{ + BDRVParallelsState *s = bs->opaque; + QEMUIOVector qiov; + int64_t off, high_off, size, sector_num; + uint32_t i, idx_host; + int ret = 0, n; + g_autofree uint32_t *reversed_bat = NULL; + g_autofree int64_t *cluster_buf = NULL; + bool sync_and_truncate = false; + + /* + * Make a reversed BAT. + * Each cluster in the host file could represent only one cluster + * from the guest point of view. Reversed BAT provides mapping of that type. + * Initially the table is filled with REVERSED_BAT_UNTOUCHED values. + */ + reversed_bat = g_malloc(s->bat_size * sizeof(uint32_t)); + for (i = 0; i < s->bat_size; i++) { + reversed_bat[i] = REVERSED_BAT_UNTOUCHED; + } + + cluster_buf = g_malloc(s->cluster_size); + qemu_iovec_init(&qiov, 0); + qemu_iovec_add(&qiov, cluster_buf, s->cluster_size); + + high_off = 0; + for (i = 0; i < s->bat_size; i++) { + off = bat2sect(s, i) << BDRV_SECTOR_BITS; + if (off == 0) { + continue; + } + + if (off > high_off) { + high_off = off; + } + + idx_host = HOST_CLUSTER_INDEX(s, off); + if (idx_host >= s->bat_size) { + res->check_errors++; + goto out; + } + + if (reversed_bat[idx_host] != REVERSED_BAT_UNTOUCHED) { + /* + * We have alreade written a guest cluster index for this + * host cluster. It means there is a duplicated offset in BAT. + */ + fprintf(stderr, + "%s BAT offset in entry %u duplicates offset in entry %u\n", + fix & BDRV_FIX_ERRORS ? "Repairing" : "ERROR", + i, reversed_bat[idx_host]); + res->corruptions++; + + if (fix & BDRV_FIX_ERRORS) { + /* + * Write zero to the current BAT entry, allocate a new cluster + * for the relevant guest offset and copy the host cluster + * to the new allocated cluster. + * In this way mwe will have two identical clusters and two + * BAT entries with the offsets of these clusters. + */ + s->bat_bitmap[i] = 0; + + sector_num = bat2sect(s, reversed_bat[idx_host]); + ret = bdrv_pread(bs->file, sector_num << BDRV_SECTOR_BITS, + s->cluster_size, cluster_buf, 0); + if (ret < 0) { + res->check_errors++; + goto out; + } + + sector_num = (i * s->cluster_size) >> BDRV_SECTOR_BITS; + off = allocate_clusters(bs, sector_num, s->tracks, &n); + if (off < 0) { + res->check_errors++; + ret = off; + goto out; + } + off <<= BDRV_SECTOR_BITS; + + ret = bdrv_co_pwritev(bs->file, off, s->cluster_size, &qiov, 0); + if (ret < 0) { + res->check_errors++; + goto out; + } + + /* off is new and we should repair idx_host accordingly. */ + idx_host = HOST_CLUSTER_INDEX(s, off); + res->corruptions_fixed++; + sync_and_truncate = true; + } + } + reversed_bat[idx_host] = i; + } + + if (sync_and_truncate) { + ret = sync_header(bs, res); + if (ret < 0) { + goto out; + } + + size = bdrv_getlength(bs->file->bs); + if (size < 0) { + res->check_errors++; + ret = size; + goto out; + } + + res->image_end_offset = high_off + s->cluster_size; + if (size > res->image_end_offset) { + ret = truncate_file(bs, res->image_end_offset); + if (ret < 0) { + goto out; + } + } + } + +out: + qemu_iovec_destroy(&qiov); + return ret; +} + static void collect_statistics(BlockDriverState *bs, BdrvCheckResult *res) { BDRVParallelsState *s = bs->opaque; @@ -598,6 +728,11 @@ static int coroutine_fn parallels_co_check(BlockDriverState *bs, goto out; } + ret = check_duplicate(bs, res, fix); + if (ret != 0) { + goto out; + } + collect_statistics(bs, res); out: -- 2.34.1