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-rw-r--r--block/qcow2-refcount.c20
-rw-r--r--block/qcow2.h6
2 files changed, 19 insertions, 7 deletions
diff --git a/block/qcow2-refcount.c b/block/qcow2-refcount.c
index 46082aeac1..1c63ac244a 100644
--- a/block/qcow2-refcount.c
+++ b/block/qcow2-refcount.c
@@ -31,7 +31,8 @@
#include "qemu/bswap.h"
#include "qemu/cutils.h"
-static int64_t alloc_clusters_noref(BlockDriverState *bs, uint64_t size);
+static int64_t alloc_clusters_noref(BlockDriverState *bs, uint64_t size,
+ uint64_t max);
static int QEMU_WARN_UNUSED_RESULT update_refcount(BlockDriverState *bs,
int64_t offset, int64_t length, uint64_t addend,
bool decrease, enum qcow2_discard_type type);
@@ -362,7 +363,7 @@ static int alloc_refcount_block(BlockDriverState *bs,
}
/* Allocate the refcount block itself and mark it as used */
- int64_t new_block = alloc_clusters_noref(bs, s->cluster_size);
+ int64_t new_block = alloc_clusters_noref(bs, s->cluster_size, INT64_MAX);
if (new_block < 0) {
return new_block;
}
@@ -954,7 +955,8 @@ int qcow2_update_cluster_refcount(BlockDriverState *bs,
/* return < 0 if error */
-static int64_t alloc_clusters_noref(BlockDriverState *bs, uint64_t size)
+static int64_t alloc_clusters_noref(BlockDriverState *bs, uint64_t size,
+ uint64_t max)
{
BDRVQcow2State *s = bs->opaque;
uint64_t i, nb_clusters, refcount;
@@ -979,9 +981,9 @@ retry:
}
/* Make sure that all offsets in the "allocated" range are representable
- * in an int64_t */
+ * in the requested max */
if (s->free_cluster_index > 0 &&
- s->free_cluster_index - 1 > (INT64_MAX >> s->cluster_bits))
+ s->free_cluster_index - 1 > (max >> s->cluster_bits))
{
return -EFBIG;
}
@@ -1001,7 +1003,7 @@ int64_t qcow2_alloc_clusters(BlockDriverState *bs, uint64_t size)
BLKDBG_EVENT(bs->file, BLKDBG_CLUSTER_ALLOC);
do {
- offset = alloc_clusters_noref(bs, size);
+ offset = alloc_clusters_noref(bs, size, QCOW_MAX_CLUSTER_OFFSET);
if (offset < 0) {
return offset;
}
@@ -1083,7 +1085,11 @@ int64_t qcow2_alloc_bytes(BlockDriverState *bs, int size)
free_in_cluster = s->cluster_size - offset_into_cluster(s, offset);
do {
if (!offset || free_in_cluster < size) {
- int64_t new_cluster = alloc_clusters_noref(bs, s->cluster_size);
+ int64_t new_cluster;
+
+ new_cluster = alloc_clusters_noref(bs, s->cluster_size,
+ MIN(s->cluster_offset_mask,
+ QCOW_MAX_CLUSTER_OFFSET));
if (new_cluster < 0) {
return new_cluster;
}
diff --git a/block/qcow2.h b/block/qcow2.h
index 29c98d87a0..8662b68575 100644
--- a/block/qcow2.h
+++ b/block/qcow2.h
@@ -42,6 +42,12 @@
#define QCOW_MAX_CRYPT_CLUSTERS 32
#define QCOW_MAX_SNAPSHOTS 65536
+/* Field widths in qcow2 mean normal cluster offsets cannot reach
+ * 64PB; depending on cluster size, compressed clusters can have a
+ * smaller limit (64PB for up to 16k clusters, then ramps down to
+ * 512TB for 2M clusters). */
+#define QCOW_MAX_CLUSTER_OFFSET ((1ULL << 56) - 1)
+
/* 8 MB refcount table is enough for 2 PB images at 64k cluster size
* (128 GB for 512 byte clusters, 2 EB for 2 MB clusters) */
#define QCOW_MAX_REFTABLE_SIZE S_8MiB