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() and highest_offset() helpers 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 | 168 +++++++++++++++++++++++++++++++++++++++++-----
1 file changed, 151 insertions(+), 17 deletions(-)
diff --git a/block/parallels.c b/block/parallels.c
index da1e75096c..73e992875a 100644
--- a/block/parallels.c
+++ b/block/parallels.c
@@ -136,6 +136,26 @@ 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 highest_offset(BDRVParallelsState *s)
+{
+ int64_t off, high_off = 0;
+ int i;
+
+ for (i = 0; i < s->bat_size; i++) {
+ off = bat2sect(s, i) << BDRV_SECTOR_BITS;
+ if (off > high_off) {
+ high_off = off;
+ }
+ }
+ return high_off;
+}
+
static int64_t block_status(BDRVParallelsState *s, int64_t sector_num,
int nb_sectors, int *pnum)
{
@@ -518,17 +538,9 @@ static int parallels_check_leak(BlockDriverState *bs,
BdrvCheckMode fix)
{
BDRVParallelsState *s = bs->opaque;
- int64_t off, high_off, count, leak_size;
- uint32_t i;
- int ret;
+ int64_t high_off, count, leak_size;
- high_off = 0;
- for (i = 0; i < s->bat_size; i++) {
- off = bat2sect(s, i) << BDRV_SECTOR_BITS;
- if (off > high_off) {
- high_off = off;
- }
- }
+ high_off = highest_offset(s);
res->image_end_offset = high_off + s->cluster_size;
@@ -541,13 +553,6 @@ static int parallels_check_leak(BlockDriverState *bs,
return 0;
}
- if (fix & BDRV_FIX_LEAKS) {
- ret = parallels_fix_leak(bs, res);
- if (ret < 0) {
- return ret;
- }
- }
-
count = DIV_ROUND_UP(leak_size, s->cluster_size);
fprintf(stderr, "%s space leaked at the end of the image %" PRId64 "\n",
fix & BDRV_FIX_LEAKS ? "Repairing" : "ERROR", leak_size);
@@ -560,6 +565,122 @@ static int parallels_check_leak(BlockDriverState *bs,
return 0;
}
+static int parallels_check_duplicate(BlockDriverState *bs,
+ BdrvCheckResult *res,
+ BdrvCheckMode *fix)
+{
+ BDRVParallelsState *s = bs->opaque;
+ QEMUIOVector qiov;
+ int64_t off, high_off, sector;
+ unsigned long *bitmap;
+ uint32_t i, bitmap_size, cluster_index;
+ int n, ret = 0;
+ uint64_t *buf = NULL;
+
+ high_off = highest_offset(s);
+ if (high_off == 0) {
+ return 0;
+ }
+
+ /*
+ * 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, high_off) + 1;
+ 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;
+ if (off > high_off) {
+ high_off = off;
+ }
+
+ ret = bdrv_co_pwritev(bs->file, off, s->cluster_size, &qiov,
0);
+ if (ret < 0) {
+ res->check_errors++;
+ goto out;
+ }
+
+ /*
+ * 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++;
+ }
+ res->image_end_offset = high_off + s->cluster_size;
+ } 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)
@@ -608,7 +729,20 @@ 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 &&
+ (res->corruptions_fixed || res->leaks_fixed)) {
+ ret = parallels_fix_leak(bs, res);
+ if (ret < 0) {
+ return ret;
+ }
+ }
}
ret = bdrv_co_flush(bs);