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qcow2: Make size_to_clusters() return uint64_t
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Sadly, some images may have more clusters than what can be represented
using a plain int. We should be prepared for that case (in
qcow2_check_refcounts() we actually were trying to catch that case, but
since size_to_clusters() truncated the returned value, that check never
did anything useful).

Cc: qemu-stable <[email protected]>
Signed-off-by: Max Reitz <[email protected]>
Signed-off-by: Kevin Wolf <[email protected]>
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@XanClic @kevmw
XanClic authored and kevmw committed Sep 14, 2015
1 parent 231f66d commit b6d36de
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Showing 3 changed files with 29 additions and 17 deletions.
28 changes: 18 additions & 10 deletions block/qcow2-cluster.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -298,7 +298,7 @@ static int l2_allocate(BlockDriverState *bs, int l1_index, uint64_t **table)
* as contiguous. (This allows it, for example, to stop at the first compressed
* cluster which may require a different handling)
*/
static int count_contiguous_clusters(uint64_t nb_clusters, int cluster_size,
static int count_contiguous_clusters(int nb_clusters, int cluster_size,
uint64_t *l2_table, uint64_t stop_flags)
{
int i;
Expand All @@ -321,7 +321,7 @@ static int count_contiguous_clusters(uint64_t nb_clusters, int cluster_size,
return i;
}

static int count_contiguous_free_clusters(uint64_t nb_clusters, uint64_t *l2_table)
static int count_contiguous_free_clusters(int nb_clusters, uint64_t *l2_table)
{
int i;

Expand Down Expand Up @@ -495,6 +495,7 @@ int qcow2_get_cluster_offset(BlockDriverState *bs, uint64_t offset,
if (nb_needed > nb_available) {
nb_needed = nb_available;
}
assert(nb_needed <= INT_MAX);

*cluster_offset = 0;

Expand Down Expand Up @@ -530,6 +531,8 @@ int qcow2_get_cluster_offset(BlockDriverState *bs, uint64_t offset,

l2_index = (offset >> s->cluster_bits) & (s->l2_size - 1);
*cluster_offset = be64_to_cpu(l2_table[l2_index]);

/* nb_needed <= INT_MAX, thus nb_clusters <= INT_MAX, too */
nb_clusters = size_to_clusters(s, nb_needed << 9);

ret = qcow2_get_cluster_type(*cluster_offset);
Expand Down Expand Up @@ -960,7 +963,7 @@ static int handle_copied(BlockDriverState *bs, uint64_t guest_offset,
int l2_index;
uint64_t cluster_offset;
uint64_t *l2_table;
unsigned int nb_clusters;
uint64_t nb_clusters;
unsigned int keep_clusters;
int ret;

Expand All @@ -979,6 +982,7 @@ static int handle_copied(BlockDriverState *bs, uint64_t guest_offset,

l2_index = offset_to_l2_index(s, guest_offset);
nb_clusters = MIN(nb_clusters, s->l2_size - l2_index);
assert(nb_clusters <= INT_MAX);

/* Find L2 entry for the first involved cluster */
ret = get_cluster_table(bs, guest_offset, &l2_table, &l2_index);
Expand Down Expand Up @@ -1061,7 +1065,7 @@ static int handle_copied(BlockDriverState *bs, uint64_t guest_offset,
* restarted, but the whole request should not be failed.
*/
static int do_alloc_cluster_offset(BlockDriverState *bs, uint64_t guest_offset,
uint64_t *host_offset, unsigned int *nb_clusters)
uint64_t *host_offset, uint64_t *nb_clusters)
{
BDRVQcow2State *s = bs->opaque;

Expand All @@ -1079,7 +1083,7 @@ static int do_alloc_cluster_offset(BlockDriverState *bs, uint64_t guest_offset,
*host_offset = cluster_offset;
return 0;
} else {
int ret = qcow2_alloc_clusters_at(bs, *host_offset, *nb_clusters);
int64_t ret = qcow2_alloc_clusters_at(bs, *host_offset, *nb_clusters);
if (ret < 0) {
return ret;
}
Expand Down Expand Up @@ -1115,7 +1119,7 @@ static int handle_alloc(BlockDriverState *bs, uint64_t guest_offset,
int l2_index;
uint64_t *l2_table;
uint64_t entry;
unsigned int nb_clusters;
uint64_t nb_clusters;
int ret;

uint64_t alloc_cluster_offset;
Expand All @@ -1133,6 +1137,7 @@ static int handle_alloc(BlockDriverState *bs, uint64_t guest_offset,

l2_index = offset_to_l2_index(s, guest_offset);
nb_clusters = MIN(nb_clusters, s->l2_size - l2_index);
assert(nb_clusters <= INT_MAX);

/* Find L2 entry for the first involved cluster */
ret = get_cluster_table(bs, guest_offset, &l2_table, &l2_index);
Expand Down Expand Up @@ -1426,7 +1431,8 @@ int qcow2_decompress_cluster(BlockDriverState *bs, uint64_t cluster_offset)
* clusters.
*/
static int discard_single_l2(BlockDriverState *bs, uint64_t offset,
unsigned int nb_clusters, enum qcow2_discard_type type, bool full_discard)
uint64_t nb_clusters, enum qcow2_discard_type type,
bool full_discard)
{
BDRVQcow2State *s = bs->opaque;
uint64_t *l2_table;
Expand All @@ -1441,6 +1447,7 @@ static int discard_single_l2(BlockDriverState *bs, uint64_t offset,

/* Limit nb_clusters to one L2 table */
nb_clusters = MIN(nb_clusters, s->l2_size - l2_index);
assert(nb_clusters <= INT_MAX);

for (i = 0; i < nb_clusters; i++) {
uint64_t old_l2_entry;
Expand Down Expand Up @@ -1503,7 +1510,7 @@ int qcow2_discard_clusters(BlockDriverState *bs, uint64_t offset,
{
BDRVQcow2State *s = bs->opaque;
uint64_t end_offset;
unsigned int nb_clusters;
uint64_t nb_clusters;
int ret;

end_offset = offset + (nb_sectors << BDRV_SECTOR_BITS);
Expand Down Expand Up @@ -1545,7 +1552,7 @@ int qcow2_discard_clusters(BlockDriverState *bs, uint64_t offset,
* clusters.
*/
static int zero_single_l2(BlockDriverState *bs, uint64_t offset,
unsigned int nb_clusters)
uint64_t nb_clusters)
{
BDRVQcow2State *s = bs->opaque;
uint64_t *l2_table;
Expand All @@ -1560,6 +1567,7 @@ static int zero_single_l2(BlockDriverState *bs, uint64_t offset,

/* Limit nb_clusters to one L2 table */
nb_clusters = MIN(nb_clusters, s->l2_size - l2_index);
assert(nb_clusters <= INT_MAX);

for (i = 0; i < nb_clusters; i++) {
uint64_t old_offset;
Expand All @@ -1584,7 +1592,7 @@ static int zero_single_l2(BlockDriverState *bs, uint64_t offset,
int qcow2_zero_clusters(BlockDriverState *bs, uint64_t offset, int nb_sectors)
{
BDRVQcow2State *s = bs->opaque;
unsigned int nb_clusters;
uint64_t nb_clusters;
int ret;

/* The zero flag is only supported by version 3 and newer */
Expand Down
12 changes: 8 additions & 4 deletions block/qcow2-refcount.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -875,8 +875,8 @@ int64_t qcow2_alloc_clusters(BlockDriverState *bs, uint64_t size)
return offset;
}

int qcow2_alloc_clusters_at(BlockDriverState *bs, uint64_t offset,
int nb_clusters)
int64_t qcow2_alloc_clusters_at(BlockDriverState *bs, uint64_t offset,
int64_t nb_clusters)
{
BDRVQcow2State *s = bs->opaque;
uint64_t cluster_index, refcount;
Expand Down Expand Up @@ -1259,7 +1259,7 @@ static size_t refcount_array_byte_size(BDRVQcow2State *s, uint64_t entries)
static int realloc_refcount_array(BDRVQcow2State *s, void **array,
int64_t *size, int64_t new_size)
{
size_t old_byte_size, new_byte_size;
int64_t old_byte_size, new_byte_size;
void *new_ptr;

/* Round to clusters so the array can be directly written to disk */
Expand All @@ -1275,13 +1275,17 @@ static int realloc_refcount_array(BDRVQcow2State *s, void **array,

assert(new_byte_size > 0);

if (new_byte_size > SIZE_MAX) {
return -ENOMEM;
}

new_ptr = g_try_realloc(*array, new_byte_size);
if (!new_ptr) {
return -ENOMEM;
}

if (new_byte_size > old_byte_size) {
memset((void *)((uintptr_t)new_ptr + old_byte_size), 0,
memset((char *)new_ptr + old_byte_size, 0,
new_byte_size - old_byte_size);
}

Expand Down
6 changes: 3 additions & 3 deletions block/qcow2.h
View file
Original file line number Diff line number Diff line change
Expand Up @@ -415,7 +415,7 @@ static inline int64_t offset_into_cluster(BDRVQcow2State *s, int64_t offset)
return offset & (s->cluster_size - 1);
}

static inline int size_to_clusters(BDRVQcow2State *s, int64_t size)
static inline uint64_t size_to_clusters(BDRVQcow2State *s, uint64_t size)
{
return (size + (s->cluster_size - 1)) >> s->cluster_bits;
}
Expand Down Expand Up @@ -509,8 +509,8 @@ int qcow2_update_cluster_refcount(BlockDriverState *bs, int64_t cluster_index,
enum qcow2_discard_type type);

int64_t qcow2_alloc_clusters(BlockDriverState *bs, uint64_t size);
int qcow2_alloc_clusters_at(BlockDriverState *bs, uint64_t offset,
int nb_clusters);
int64_t qcow2_alloc_clusters_at(BlockDriverState *bs, uint64_t offset,
int64_t nb_clusters);
int64_t qcow2_alloc_bytes(BlockDriverState *bs, int size);
void qcow2_free_clusters(BlockDriverState *bs,
int64_t offset, int64_t size,
Expand Down

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