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.
Move parallels_fix_leak() call to parallels_co_check() to fix both types
of leak: real corruption and a leak produced by allocate_clusters()
during deduplication.
Signed-off-by: Alexander Ivanov <alexander.ivanov@virtuozzo.com>
---
block/parallels.c | 134 ++++++++++++++++++++++++++++++++++++++++++++--
1 file changed, 129 insertions(+), 5 deletions(-)
diff --git a/block/parallels.c b/block/parallels.c
index d3053b33d2..3ba8f42131 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->header->data_off << BDRV_SECTOR_BITS;
+ return off / s->cluster_size;
+}
+
static int64_t block_status(BDRVParallelsState *s, int64_t sector_num,
int nb_sectors, int *pnum)
{
@@ -531,7 +537,6 @@ static int parallels_check_leak(BlockDriverState *bs,
{
BDRVParallelsState *s = bs->opaque;
int64_t count, leak_size;
- int ret;
leak_size = parallels_get_leak_size(bs, res);
if (leak_size < 0) {
@@ -548,16 +553,123 @@ static int parallels_check_leak(BlockDriverState *bs,
fix & BDRV_FIX_LEAKS ? "Repairing" : "ERROR", leak_size);
if (fix & BDRV_FIX_LEAKS) {
- ret = parallels_fix_leak(bs, res);
- if (ret < 0) {
- return ret;
- }
res->leaks_fixed += count;
}
return 0;
}
+static int parallels_check_duplicate(BlockDriverState *bs,
+ BdrvCheckResult *res,
+ BdrvCheckMode *fix)
+{
+ BDRVParallelsState *s = bs->opaque;
+ QEMUIOVector qiov;
+ int64_t off, sector;
+ unsigned long *bitmap;
+ uint32_t i, bitmap_size, cluster_index;
+ int n, ret = 0;
+ uint64_t *buf = NULL;
+
+ /*
+ * 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);
+ bitmap = bitmap_new(bitmap_size);
+
+ buf = qemu_memalign(4096, s->cluster_size);
+ qemu_iovec_init(&qiov, 0);
+ qemu_iovec_add(&qiov, buf, s->cluster_size);
+
+ for (i = 0; i < s->bat_size; i++) {
+ off = bat2sect(s, i) << BDRV_SECTOR_BITS;
+ if (off == 0) {
+ continue;
+ }
+
+ cluster_index = host_cluster_index(s, off);
+ if (test_bit(cluster_index, bitmap)) {
+ /* 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) {
+ /*
+ * 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.
+ */
+ parallels_set_bat_entry(s, i, 0);
+
+ ret = bdrv_co_pread(bs->file, off, s->cluster_size, buf, 0);
+ if (ret < 0) {
+ res->check_errors++;
+ goto out;
+ }
+
+ sector = (i * s->cluster_size) >> BDRV_SECTOR_BITS;
+ sector = allocate_clusters(bs, sector, s->tracks, &n);
+ if (sector < 0) {
+ res->check_errors++;
+ ret = sector;
+ goto out;
+ }
+ off = sector << BDRV_SECTOR_BITS;
+
+ ret = bdrv_co_pwritev(bs->file, off, s->cluster_size, &qiov, 0);
+ if (ret < 0) {
+ res->check_errors++;
+ goto out;
+ }
+
+ if (off + s->cluster_size > res->image_end_offset) {
+ res->image_end_offset = 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, off);
+ if (cluster_index < bitmap_size) {
+ bitmap_set(bitmap, cluster_index, 1);
+ }
+
+ /*
+ * When new clusters are allocated, file size increases by
+ * 128 Mb blocks. We need to truncate the file to the right
+ * size. Let the leak fix code make its job.
+ */
+ *fix |= BDRV_FIX_LEAKS;
+ res->corruptions_fixed++;
+ }
+ } else {
+ bitmap_set(bitmap, cluster_index, 1);
+ }
+ }
+
+out:
+ qemu_iovec_destroy(&qiov);
+ g_free(buf);
+ g_free(bitmap);
+ return ret;
+}
+
static void parallels_collect_statistics(BlockDriverState *bs,
BdrvCheckResult *res,
BdrvCheckMode fix)
@@ -609,7 +721,19 @@ static int coroutine_fn parallels_co_check(BlockDriverState *bs,
return ret;
}
+ ret = parallels_check_duplicate(bs, res, &fix);
+ if (ret < 0) {
+ return ret;
+ }
+
parallels_collect_statistics(bs, res, fix);
+
+ if (fix & BDRV_FIX_LEAKS) {
+ ret = parallels_fix_leak(bs, res);
+ if (ret < 0) {
+ return ret;
+ }
+ }
}
ret = bdrv_co_flush(bs);
--
2.34.1
© 2016 - 2024 Red Hat, Inc.