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[PATCH v4 06/10] qcow2-refcount: check_refcounts_l2(): check l2_bitmap
From: |
Vladimir Sementsov-Ogievskiy |
Subject: |
[PATCH v4 06/10] qcow2-refcount: check_refcounts_l2(): check l2_bitmap |
Date: |
Tue, 14 Sep 2021 15:24:50 +0300 |
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>
---
block/qcow2-refcount.c | 28 ++++++++++++++++++++++++++--
1 file changed, 26 insertions(+), 2 deletions(-)
diff --git a/block/qcow2-refcount.c b/block/qcow2-refcount.c
index f48c5e1b5d..9a5ae3cac4 100644
--- a/block/qcow2-refcount.c
+++ b/block/qcow2-refcount.c
@@ -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:
--
2.29.2
- [PATCH v4 00/10] qcow2 check: check some reserved bits and subcluster bitmaps, Vladimir Sementsov-Ogievskiy, 2021/09/14
- [PATCH v4 04/10] qcow2-refcount: introduce fix_l2_entry_by_zero(), Vladimir Sementsov-Ogievskiy, 2021/09/14
- [PATCH v4 01/10] qcow2-refcount: improve style of check_refcounts_l2(), Vladimir Sementsov-Ogievskiy, 2021/09/14
- [PATCH v4 05/10] qcow2-refcount: fix_l2_entry_by_zero(): also zero L2 entry bitmap, Vladimir Sementsov-Ogievskiy, 2021/09/14
- [PATCH v4 03/10] qcow2: introduce qcow2_parse_compressed_l2_entry() helper, Vladimir Sementsov-Ogievskiy, 2021/09/14
- [PATCH v4 02/10] qcow2: compressed read: simplify cluster descriptor passing, Vladimir Sementsov-Ogievskiy, 2021/09/14
- [PATCH v4 09/10] qcow2-refcount: check_refcounts_l1(): check reserved bits, Vladimir Sementsov-Ogievskiy, 2021/09/14
- [PATCH v4 06/10] qcow2-refcount: check_refcounts_l2(): check l2_bitmap,
Vladimir Sementsov-Ogievskiy <=
- [PATCH v4 10/10] qcow2-refcount: check_refblocks(): add separate message for reserved, Vladimir Sementsov-Ogievskiy, 2021/09/14
- [PATCH v4 07/10] qcow2-refcount: check_refcounts_l2(): check reserved bits, Vladimir Sementsov-Ogievskiy, 2021/09/14
- [PATCH v4 08/10] qcow2-refcount: improve style of check_refcounts_l1(), Vladimir Sementsov-Ogievskiy, 2021/09/14
- Re: [PATCH v4 00/10] qcow2 check: check some reserved bits and subcluster bitmaps, Hanna Reitz, 2021/09/15