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Diffstat (limited to 'block/qcow2-refcount.c')
-rw-r--r--block/qcow2-refcount.c130
1 files changed, 81 insertions, 49 deletions
diff --git a/block/qcow2-refcount.c b/block/qcow2-refcount.c
index e86a1d6ccf..497364f673 100644
--- a/block/qcow2-refcount.c
+++ b/block/qcow2-refcount.c
@@ -1095,6 +1095,63 @@ fail:
/* refcount checking functions */
+static size_t refcount_array_byte_size(BDRVQcowState *s, uint64_t entries)
+{
+ /* This assertion holds because there is no way we can address more than
+ * 2^(64 - 9) clusters at once (with cluster size 512 = 2^9, and because
+ * offsets have to be representable in bytes); due to every cluster
+ * corresponding to one refcount entry, we are well below that limit */
+ assert(entries < (UINT64_C(1) << (64 - 9)));
+
+ /* Thanks to the assertion this will not overflow, because
+ * s->refcount_order < 7.
+ * (note: x << s->refcount_order == x * s->refcount_bits) */
+ return DIV_ROUND_UP(entries << s->refcount_order, 8);
+}
+
+/**
+ * Reallocates *array so that it can hold new_size entries. *size must contain
+ * the current number of entries in *array. If the reallocation fails, *array
+ * and *size will not be modified and -errno will be returned. If the
+ * reallocation is successful, *array will be set to the new buffer, *size
+ * will be set to new_size and 0 will be returned. The size of the reallocated
+ * refcount array buffer will be aligned to a cluster boundary, and the newly
+ * allocated area will be zeroed.
+ */
+static int realloc_refcount_array(BDRVQcowState *s, uint16_t **array,
+ int64_t *size, int64_t new_size)
+{
+ size_t old_byte_size, new_byte_size;
+ uint16_t *new_ptr;
+
+ /* Round to clusters so the array can be directly written to disk */
+ old_byte_size = size_to_clusters(s, refcount_array_byte_size(s, *size))
+ * s->cluster_size;
+ new_byte_size = size_to_clusters(s, refcount_array_byte_size(s, new_size))
+ * s->cluster_size;
+
+ if (new_byte_size == old_byte_size) {
+ *size = new_size;
+ return 0;
+ }
+
+ assert(new_byte_size > 0);
+
+ 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,
+ new_byte_size - old_byte_size);
+ }
+
+ *array = new_ptr;
+ *size = new_size;
+
+ return 0;
+}
/*
* Increases the refcount for a range of clusters in a given refcount table.
@@ -1111,6 +1168,7 @@ static int inc_refcounts(BlockDriverState *bs,
{
BDRVQcowState *s = bs->opaque;
uint64_t start, last, cluster_offset, k;
+ int ret;
if (size <= 0) {
return 0;
@@ -1122,23 +1180,12 @@ static int inc_refcounts(BlockDriverState *bs,
cluster_offset += s->cluster_size) {
k = cluster_offset >> s->cluster_bits;
if (k >= *refcount_table_size) {
- int64_t old_refcount_table_size = *refcount_table_size;
- uint16_t *new_refcount_table;
-
- *refcount_table_size = k + 1;
- new_refcount_table = g_try_realloc(*refcount_table,
- *refcount_table_size *
- sizeof(**refcount_table));
- if (!new_refcount_table) {
- *refcount_table_size = old_refcount_table_size;
+ ret = realloc_refcount_array(s, refcount_table,
+ refcount_table_size, k + 1);
+ if (ret < 0) {
res->check_errors++;
- return -ENOMEM;
+ return ret;
}
- *refcount_table = new_refcount_table;
-
- memset(*refcount_table + old_refcount_table_size, 0,
- (*refcount_table_size - old_refcount_table_size) *
- sizeof(**refcount_table));
}
if (++(*refcount_table)[k] == 0) {
@@ -1507,8 +1554,7 @@ static int check_refblocks(BlockDriverState *bs, BdrvCheckResult *res,
fix & BDRV_FIX_ERRORS ? "Repairing" : "ERROR", i);
if (fix & BDRV_FIX_ERRORS) {
- int64_t old_nb_clusters = *nb_clusters;
- uint16_t *new_refcount_table;
+ int64_t new_nb_clusters;
if (offset > INT64_MAX - s->cluster_size) {
ret = -EINVAL;
@@ -1525,22 +1571,15 @@ static int check_refblocks(BlockDriverState *bs, BdrvCheckResult *res,
goto resize_fail;
}
- *nb_clusters = size_to_clusters(s, size);
- assert(*nb_clusters >= old_nb_clusters);
+ new_nb_clusters = size_to_clusters(s, size);
+ assert(new_nb_clusters >= *nb_clusters);
- new_refcount_table = g_try_realloc(*refcount_table,
- *nb_clusters *
- sizeof(**refcount_table));
- if (!new_refcount_table) {
- *nb_clusters = old_nb_clusters;
+ ret = realloc_refcount_array(s, refcount_table,
+ nb_clusters, new_nb_clusters);
+ if (ret < 0) {
res->check_errors++;
- return -ENOMEM;
+ return ret;
}
- *refcount_table = new_refcount_table;
-
- memset(*refcount_table + old_nb_clusters, 0,
- (*nb_clusters - old_nb_clusters) *
- sizeof(**refcount_table));
if (cluster >= *nb_clusters) {
ret = -EINVAL;
@@ -1600,10 +1639,12 @@ static int calculate_refcounts(BlockDriverState *bs, BdrvCheckResult *res,
int ret;
if (!*refcount_table) {
- *refcount_table = g_try_new0(uint16_t, *nb_clusters);
- if (*nb_clusters && *refcount_table == NULL) {
+ int64_t old_size = 0;
+ ret = realloc_refcount_array(s, refcount_table,
+ &old_size, *nb_clusters);
+ if (ret < 0) {
res->check_errors++;
- return -ENOMEM;
+ return ret;
}
}
@@ -1737,6 +1778,7 @@ static int64_t alloc_clusters_imrt(BlockDriverState *bs,
int64_t cluster = *first_free_cluster, i;
bool first_gap = true;
int contiguous_free_clusters;
+ int ret;
/* Starting at *first_free_cluster, find a range of at least cluster_count
* continuously free clusters */
@@ -1766,28 +1808,18 @@ static int64_t alloc_clusters_imrt(BlockDriverState *bs,
/* If no such range could be found, grow the in-memory refcount table
* accordingly to append free clusters at the end of the image */
if (contiguous_free_clusters < cluster_count) {
- int64_t old_imrt_nb_clusters = *imrt_nb_clusters;
- uint16_t *new_refcount_table;
-
/* contiguous_free_clusters clusters are already empty at the image end;
* we need cluster_count clusters; therefore, we have to allocate
* cluster_count - contiguous_free_clusters new clusters at the end of
* the image (which is the current value of cluster; note that cluster
* may exceed old_imrt_nb_clusters if *first_free_cluster pointed beyond
* the image end) */
- *imrt_nb_clusters = cluster + cluster_count - contiguous_free_clusters;
- new_refcount_table = g_try_realloc(*refcount_table,
- *imrt_nb_clusters *
- sizeof(**refcount_table));
- if (!new_refcount_table) {
- *imrt_nb_clusters = old_imrt_nb_clusters;
- return -ENOMEM;
- }
- *refcount_table = new_refcount_table;
-
- memset(*refcount_table + old_imrt_nb_clusters, 0,
- (*imrt_nb_clusters - old_imrt_nb_clusters) *
- sizeof(**refcount_table));
+ ret = realloc_refcount_array(s, refcount_table, imrt_nb_clusters,
+ cluster + cluster_count
+ - contiguous_free_clusters);
+ if (ret < 0) {
+ return ret;
+ }
}
/* Go back to the first free cluster */
generated by cgit v1.2.1 (git 2.18.0) at 2024-06-16 11:57:50 +0000