Cluster offsets must be unique among all the BAT entries. Find duplicate
offsets in the BAT and fix it by copying the content of the relevant
cluster to a newly allocated cluster and set the new cluster offset to the
duplicated entry.
Add host_cluster_index() helper to deduplicate the code.
When new clusters are allocated, the file size increases by 128 Mb. Call
parallels_check_leak() to fix this leak.
Signed-off-by: Alexander Ivanov <alexander.ivanov@virtuozzo.com>
---
block/parallels.c | 144 ++++++++++++++++++++++++++++++++++++++++++++++
1 file changed, 144 insertions(+)
diff --git a/block/parallels.c b/block/parallels.c
index 374c9d17eb..0f207c4b32 100644
--- a/block/parallels.c
+++ b/block/parallels.c
@@ -136,6 +136,12 @@ static int cluster_remainder(BDRVParallelsState *s,
int64_t sector_num,
return MIN(nb_sectors, ret);
}
+static uint32_t host_cluster_index(BDRVParallelsState *s, int64_t off)
+{
+ off -= s->data_start << BDRV_SECTOR_BITS;
+ return off / s->cluster_size;
+}
+
static int64_t block_status(BDRVParallelsState *s, int64_t sector_num,
int nb_sectors, int *pnum)
{
@@ -529,6 +535,139 @@ parallels_check_leak(BlockDriverState *bs,
BdrvCheckResult *res,
return 0;
}
+static int coroutine_fn GRAPH_RDLOCK
+parallels_check_duplicate(BlockDriverState *bs, BdrvCheckResult *res,
+ BdrvCheckMode fix)
+{
+ BDRVParallelsState *s = bs->opaque;
+ int64_t host_off, host_sector, guest_sector;
+ unsigned long *bitmap;
+ uint32_t i, bitmap_size, cluster_index, bat_entry;
+ int n, ret = 0;
+ uint64_t *buf = NULL;
+ bool fixed = false;
+
+ /*
+ * Create a bitmap of used clusters.
+ * If a bit is set, there is a BAT entry pointing to this cluster.
+ * Loop through the BAT entries, check bits relevant to an entry offset.
+ * If bit is set, this entry is duplicated. Otherwise set the bit.
+ *
+ * We shouldn't worry about newly allocated clusters outside the image
+ * because they are created higher then any existing cluster pointed by
+ * a BAT entry.
+ */
+ bitmap_size = host_cluster_index(s, res->image_end_offset);
+ if (bitmap_size == 0) {
+ return 0;
+ }
+ if (res->image_end_offset % s->cluster_size) {
+ /* A not aligned image end leads to a bitmap shorter by 1 */
+ bitmap_size++;
+ }
+
+ bitmap = bitmap_new(bitmap_size);
+
+ buf = qemu_blockalign(bs, s->cluster_size);
+
+ for (i = 0; i < s->bat_size; i++) {
+ host_off = bat2sect(s, i) << BDRV_SECTOR_BITS;
+ if (host_off == 0) {
+ continue;
+ }
+
+ cluster_index = host_cluster_index(s, host_off);
+ assert(cluster_index < bitmap_size);
+ if (!test_bit(cluster_index, bitmap)) {
+ bitmap_set(bitmap, cluster_index, 1);
+ continue;
+ }
+
+ /* this cluster duplicates another one */
+ fprintf(stderr, "%s duplicate offset in BAT entry %u\n",
+ fix & BDRV_FIX_ERRORS ? "Repairing" : "ERROR", i);
+
+ res->corruptions++;
+
+ if (!(fix & BDRV_FIX_ERRORS)) {
+ continue;
+ }
+
+ /*
+ * Reset the entry and allocate a new cluster
+ * for the relevant guest offset. In this way we let
+ * the lower layer to place the new cluster properly.
+ * Copy the original cluster to the allocated one.
+ * But before save the old offset value for repairing
+ * if we have an error.
+ */
+ bat_entry = s->bat_bitmap[i];
+ parallels_set_bat_entry(s, i, 0);
+
+ ret = bdrv_co_pread(bs->file, host_off, s->cluster_size, buf, 0);
+ if (ret < 0) {
+ res->check_errors++;
+ goto out_repare_bat;
+ }
+
+ guest_sector = (i * (int64_t)s->cluster_size) >> BDRV_SECTOR_BITS;
+ host_sector = allocate_clusters(bs, guest_sector, s->tracks, &n);
+ if (host_sector < 0) {
+ res->check_errors++;
+ goto out_repare_bat;
+ }
+ host_off = host_sector << BDRV_SECTOR_BITS;
+
+ ret = bdrv_co_pwrite(bs->file, host_off, s->cluster_size, buf, 0);
+ if (ret < 0) {
+ res->check_errors++;
+ goto out_repare_bat;
+ }
+
+ if (host_off + s->cluster_size > res->image_end_offset) {
+ res->image_end_offset = host_off + s->cluster_size;
+ }
+
+ /*
+ * In the future allocate_cluster() will reuse holed offsets
+ * inside the image. Keep the used clusters bitmap content
+ * consistent for the new allocated clusters too.
+ *
+ * Note, clusters allocated outside the current image are not
+ * considered, and the bitmap size doesn't change.
+ */
+ cluster_index = host_cluster_index(s, host_off);
+ if (cluster_index < bitmap_size) {
+ bitmap_set(bitmap, cluster_index, 1);
+ }
+
+ fixed = true;
+ res->corruptions_fixed++;
+
+ }
+
+ if (fixed) {
+ /*
+ * When new clusters are allocated, the file size increases by
+ * 128 Mb. We need to truncate the file to the right size. Let
+ * the leak fix code make its job without res changing.
+ */
+ ret = parallels_check_leak(bs, res, fix, false);
+ }
+
+out_free:
+ g_free(buf);
+ g_free(bitmap);
+ return ret;
+/*
+ * We can get here only from places where index and old_offset have
+ * meaningful values.
+ */
+out_repare_bat:
+ s->bat_bitmap[i] = bat_entry;
+ goto out_free;
+}
+
static void parallels_collect_statistics(BlockDriverState *bs,
BdrvCheckResult *res,
BdrvCheckMode fix)
@@ -580,6 +719,11 @@ parallels_co_check(BlockDriverState *bs, BdrvCheckResult
*res,
return ret;
}
+ ret = parallels_check_duplicate(bs, res, fix);
+ if (ret < 0) {
+ return ret;
+ }
+
parallels_collect_statistics(bs, res, fix);
}