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qcow2-refcount: check_refcounts_l2(): check l2_bitmap

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Check subcluster bitmap of the l2 entry for different types of
clusters:

 - for compressed it must be zero
 - for allocated check consistency of two parts of the bitmap
 - for unallocated all subclusters should be unallocated
   (or zero-plain)

Signed-off-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
Tested-by: Kirill Tkhai <ktkhai@virtuozzo.com>
Message-Id: <20210914122454.141075-7-vsementsov@virtuozzo.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Reviewed-by: Hanna Reitz <hreitz@redhat.com>
Signed-off-by: Hanna Reitz <hreitz@redhat.com>
This commit is contained in:
Vladimir Sementsov-Ogievskiy 2021-09-14 15:24:50 +03:00 committed by Hanna Reitz
parent 5c3216c046
commit 9631c7822e
1 changed files with 26 additions and 2 deletions
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28
block/qcow2-refcount.c
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@ -1661,7 +1661,7 @@ static int check_refcounts_l2(BlockDriverState *bs, BdrvCheckResult *res,
int flags, BdrvCheckMode fix, bool active)
{
BDRVQcow2State *s = bs->opaque;
uint64_t l2_entry;
uint64_t l2_entry, l2_bitmap;
uint64_t next_contiguous_offset = 0;
int i, ret;
size_t l2_size_bytes = s->l2_size * l2_entry_size(s);
@ -1681,6 +1681,7 @@ static int check_refcounts_l2(BlockDriverState *bs, BdrvCheckResult *res,
uint64_t coffset;
int csize;
l2_entry = get_l2_entry(s, l2_table, i);
l2_bitmap = get_l2_bitmap(s, l2_table, i);
switch (qcow2_get_cluster_type(bs, l2_entry)) {
case QCOW2_CLUSTER_COMPRESSED:
@ -1700,6 +1701,14 @@ static int check_refcounts_l2(BlockDriverState *bs, BdrvCheckResult *res,
break;
}
if (l2_bitmap) {
fprintf(stderr, "ERROR compressed cluster %d with non-zero "
"subcluster allocation bitmap, entry=0x%" PRIx64 "\n",
i, l2_entry);
res->corruptions++;
break;
}
/* Mark cluster as used */
qcow2_parse_compressed_l2_entry(bs, l2_entry, &coffset, &csize);
ret = qcow2_inc_refcounts_imrt(
@ -1727,13 +1736,19 @@ static int check_refcounts_l2(BlockDriverState *bs, BdrvCheckResult *res,
{
uint64_t offset = l2_entry & L2E_OFFSET_MASK;
if ((l2_bitmap >> 32) & l2_bitmap) {
res->corruptions++;
fprintf(stderr, "ERROR offset=%" PRIx64 ": Allocated "
"cluster has corrupted subcluster allocation bitmap\n",
offset);
}
/* Correct offsets are cluster aligned */
if (offset_into_cluster(s, offset)) {
bool contains_data;
res->corruptions++;
if (has_subclusters(s)) {
uint64_t l2_bitmap = get_l2_bitmap(s, l2_table, i);
contains_data = (l2_bitmap & QCOW_L2_BITMAP_ALL_ALLOC);
} else {
contains_data = !(l2_entry & QCOW_OFLAG_ZERO);
@ -1799,7 +1814,16 @@ static int check_refcounts_l2(BlockDriverState *bs, BdrvCheckResult *res,
}
case QCOW2_CLUSTER_ZERO_PLAIN:
/* Impossible when image has subclusters */
assert(!l2_bitmap);
break;
case QCOW2_CLUSTER_UNALLOCATED:
if (l2_bitmap & QCOW_L2_BITMAP_ALL_ALLOC) {
res->corruptions++;
fprintf(stderr, "ERROR: Unallocated "
"cluster has non-zero subcluster allocation map\n");
}
break;
default: