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[Qemu-devel] [PATCH v2 07/21] qcow2: Helper function for refcount modifi
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From: |
Max Reitz |
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Subject: |
[Qemu-devel] [PATCH v2 07/21] qcow2: Helper function for refcount modification |
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Date: |
Fri, 14 Nov 2014 14:06:00 +0100 |
Since refcounts do not always have to be a uint16_t, all refcount blocks
and arrays in memory should not have a specific type (thus they become
pointers to void) and for accessing them, two helper functions are used
(a getter and a setter). Those functions are called indirectly through
function pointers in the BDRVQcowState so they may later be exchanged
for different refcount orders.
Signed-off-by: Max Reitz <address@hidden>
---
block/qcow2-refcount.c | 128 ++++++++++++++++++++++++++++++-------------------
block/qcow2.h | 8 ++++
2 files changed, 87 insertions(+), 49 deletions(-)
diff --git a/block/qcow2-refcount.c b/block/qcow2-refcount.c
index 18fcd0d..b3ca7d2 100644
--- a/block/qcow2-refcount.c
+++ b/block/qcow2-refcount.c
@@ -32,6 +32,11 @@ static int QEMU_WARN_UNUSED_RESULT
update_refcount(BlockDriverState *bs,
int64_t offset, int64_t length,
int addend, enum qcow2_discard_type type);
+static uint64_t get_refcount_ro4(const void *refcount_array, uint64_t index);
+
+static void set_refcount_ro4(void *refcount_array, uint64_t index,
+ uint64_t value);
+
/*********************************************************/
/* refcount handling */
@@ -42,6 +47,9 @@ int qcow2_refcount_init(BlockDriverState *bs)
unsigned int refcount_table_size2, i;
int ret;
+ s->get_refcount = &get_refcount_ro4;
+ s->set_refcount = &set_refcount_ro4;
+
assert(s->refcount_table_size <= INT_MAX / sizeof(uint64_t));
refcount_table_size2 = s->refcount_table_size * sizeof(uint64_t);
s->refcount_table = g_try_malloc(refcount_table_size2);
@@ -72,6 +80,19 @@ void qcow2_refcount_close(BlockDriverState *bs)
}
+static uint64_t get_refcount_ro4(const void *refcount_array, uint64_t index)
+{
+ return be16_to_cpu(((const uint16_t *)refcount_array)[index]);
+}
+
+static void set_refcount_ro4(void *refcount_array, uint64_t index,
+ uint64_t value)
+{
+ assert(!(value >> 16));
+ ((uint16_t *)refcount_array)[index] = cpu_to_be16(value);
+}
+
+
static int load_refcount_block(BlockDriverState *bs,
int64_t refcount_block_offset,
void **refcount_block)
@@ -97,7 +118,7 @@ int64_t qcow2_get_refcount(BlockDriverState *bs, int64_t
cluster_index)
uint64_t refcount_table_index, block_index;
int64_t refcount_block_offset;
int ret;
- uint16_t *refcount_block;
+ void *refcount_block;
int64_t refcount;
refcount_table_index = cluster_index >> s->refcount_block_bits;
@@ -116,20 +137,24 @@ int64_t qcow2_get_refcount(BlockDriverState *bs, int64_t
cluster_index)
}
ret = qcow2_cache_get(bs, s->refcount_block_cache, refcount_block_offset,
- (void**) &refcount_block);
+ &refcount_block);
if (ret < 0) {
return ret;
}
block_index = cluster_index & (s->refcount_block_size - 1);
- refcount = be16_to_cpu(refcount_block[block_index]);
+ refcount = s->get_refcount(refcount_block, block_index);
- ret = qcow2_cache_put(bs, s->refcount_block_cache,
- (void**) &refcount_block);
+ ret = qcow2_cache_put(bs, s->refcount_block_cache, &refcount_block);
if (ret < 0) {
return ret;
}
+ if (refcount < 0) {
+ /* overflow */
+ return -ERANGE;
+ }
+
return refcount;
}
@@ -169,7 +194,7 @@ static int in_same_refcount_block(BDRVQcowState *s,
uint64_t offset_a,
* Returns 0 on success or -errno in error case
*/
static int alloc_refcount_block(BlockDriverState *bs,
- int64_t cluster_index, uint16_t **refcount_block)
+ int64_t cluster_index, void **refcount_block)
{
BDRVQcowState *s = bs->opaque;
unsigned int refcount_table_index;
@@ -196,7 +221,7 @@ static int alloc_refcount_block(BlockDriverState *bs,
}
return load_refcount_block(bs, refcount_block_offset,
- (void**) refcount_block);
+ refcount_block);
}
}
@@ -256,7 +281,7 @@ static int alloc_refcount_block(BlockDriverState *bs,
/* The block describes itself, need to update the cache */
int block_index = (new_block >> s->cluster_bits) &
(s->refcount_block_size - 1);
- (*refcount_block)[block_index] = cpu_to_be16(1);
+ s->set_refcount(*refcount_block, block_index, 1);
} else {
/* Described somewhere else. This can recurse at most twice before we
* arrive at a block that describes itself. */
@@ -274,7 +299,7 @@ static int alloc_refcount_block(BlockDriverState *bs,
/* Initialize the new refcount block only after updating its refcount,
* update_refcount uses the refcount cache itself */
ret = qcow2_cache_get_empty(bs, s->refcount_block_cache, new_block,
- (void**) refcount_block);
+ refcount_block);
if (ret < 0) {
goto fail_block;
}
@@ -308,7 +333,7 @@ static int alloc_refcount_block(BlockDriverState *bs,
return -EAGAIN;
}
- ret = qcow2_cache_put(bs, s->refcount_block_cache, (void**)
refcount_block);
+ ret = qcow2_cache_put(bs, s->refcount_block_cache, refcount_block);
if (ret < 0) {
goto fail_block;
}
@@ -362,7 +387,7 @@ static int alloc_refcount_block(BlockDriverState *bs,
s->cluster_size;
uint64_t table_offset = meta_offset + blocks_clusters * s->cluster_size;
uint64_t *new_table = g_try_new0(uint64_t, table_size);
- uint16_t *new_blocks = g_try_malloc0(blocks_clusters * s->cluster_size);
+ void *new_blocks = g_try_malloc0_n(blocks_clusters, s->cluster_size);
assert(table_size > 0 && blocks_clusters > 0);
if (new_table == NULL || new_blocks == NULL) {
@@ -384,7 +409,7 @@ static int alloc_refcount_block(BlockDriverState *bs,
uint64_t table_clusters = size_to_clusters(s, table_size *
sizeof(uint64_t));
int block = 0;
for (i = 0; i < table_clusters + blocks_clusters; i++) {
- new_blocks[block++] = cpu_to_be16(1);
+ s->set_refcount(new_blocks, block++, 1);
}
/* Write refcount blocks to disk */
@@ -437,7 +462,7 @@ static int alloc_refcount_block(BlockDriverState *bs,
qcow2_free_clusters(bs, old_table_offset, old_table_size *
sizeof(uint64_t),
QCOW2_DISCARD_OTHER);
- ret = load_refcount_block(bs, new_block, (void**) refcount_block);
+ ret = load_refcount_block(bs, new_block, refcount_block);
if (ret < 0) {
return ret;
}
@@ -452,7 +477,7 @@ fail_table:
g_free(new_table);
fail_block:
if (*refcount_block != NULL) {
- qcow2_cache_put(bs, s->refcount_block_cache, (void**) refcount_block);
+ qcow2_cache_put(bs, s->refcount_block_cache, refcount_block);
}
return ret;
}
@@ -532,7 +557,7 @@ static int QEMU_WARN_UNUSED_RESULT
update_refcount(BlockDriverState *bs,
{
BDRVQcowState *s = bs->opaque;
int64_t start, last, cluster_offset;
- uint16_t *refcount_block = NULL;
+ void *refcount_block = NULL;
int64_t old_table_index = -1;
int ret;
@@ -583,7 +608,12 @@ static int QEMU_WARN_UNUSED_RESULT
update_refcount(BlockDriverState *bs,
/* we can update the count and save it */
block_index = cluster_index & (s->refcount_block_size - 1);
- refcount = be16_to_cpu(refcount_block[block_index]);
+ refcount = s->get_refcount(refcount_block, block_index);
+ if (refcount < 0) {
+ ret = -ERANGE;
+ goto fail;
+ }
+
refcount += addend;
if (refcount < 0 || refcount > s->refcount_max) {
ret = -EINVAL;
@@ -592,7 +622,7 @@ static int QEMU_WARN_UNUSED_RESULT
update_refcount(BlockDriverState *bs,
if (refcount == 0 && cluster_index < s->free_cluster_index) {
s->free_cluster_index = cluster_index;
}
- refcount_block[block_index] = cpu_to_be16(refcount);
+ s->set_refcount(refcount_block, block_index, refcount);
if (refcount == 0 && s->discard_passthrough[type]) {
update_refcount_discard(bs, cluster_offset, s->cluster_size);
@@ -608,8 +638,7 @@ fail:
/* Write last changed block to disk */
if (refcount_block) {
int wret;
- wret = qcow2_cache_put(bs, s->refcount_block_cache,
- (void**) &refcount_block);
+ wret = qcow2_cache_put(bs, s->refcount_block_cache, &refcount_block);
if (wret < 0) {
return ret < 0 ? ret : wret;
}
@@ -1131,7 +1160,7 @@ static size_t refcount_array_byte_size(BDRVQcowState *s,
uint64_t entries)
}
}
-static int realloc_refcount_array(BDRVQcowState *s, uint16_t **array,
+static int realloc_refcount_array(BDRVQcowState *s, void **array,
int64_t *size, int64_t new_size)
{
/* Round to clusters so the array can be directly written to disk */
@@ -1139,7 +1168,7 @@ static int realloc_refcount_array(BDRVQcowState *s,
uint16_t **array,
s->cluster_size);
size_t new_byte_size = ROUND_UP(refcount_array_byte_size(s, new_size),
s->cluster_size);
- uint16_t *new_ptr;
+ void *new_ptr;
new_ptr = g_try_realloc(*array, new_byte_size);
if (new_byte_size && !new_ptr) {
@@ -1166,12 +1195,13 @@ static int realloc_refcount_array(BDRVQcowState *s,
uint16_t **array,
*/
static int inc_refcounts(BlockDriverState *bs,
BdrvCheckResult *res,
- uint16_t **refcount_table,
+ void **refcount_table,
int64_t *refcount_table_size,
int64_t offset, int64_t size)
{
BDRVQcowState *s = bs->opaque;
uint64_t start, last, cluster_offset, k;
+ int64_t refcount;
int ret;
if (size <= 0) {
@@ -1192,11 +1222,14 @@ static int inc_refcounts(BlockDriverState *bs,
}
}
- if (++(*refcount_table)[k] == 0) {
+ refcount = s->get_refcount(*refcount_table, k);
+ if (refcount == s->refcount_max) {
fprintf(stderr, "ERROR: overflow cluster offset=0x%" PRIx64
"\n", cluster_offset);
res->corruptions++;
+ continue;
}
+ s->set_refcount(*refcount_table, k, refcount + 1);
}
return 0;
@@ -1216,7 +1249,7 @@ enum {
* error occurred.
*/
static int check_refcounts_l2(BlockDriverState *bs, BdrvCheckResult *res,
- uint16_t **refcount_table, int64_t *refcount_table_size, int64_t l2_offset,
+ void **refcount_table, int64_t *refcount_table_size, int64_t l2_offset,
int flags)
{
BDRVQcowState *s = bs->opaque;
@@ -1334,7 +1367,7 @@ fail:
*/
static int check_refcounts_l1(BlockDriverState *bs,
BdrvCheckResult *res,
- uint16_t **refcount_table,
+ void **refcount_table,
int64_t *refcount_table_size,
int64_t l1_table_offset, int l1_size,
int flags)
@@ -1531,7 +1564,7 @@ fail:
*/
static int check_refblocks(BlockDriverState *bs, BdrvCheckResult *res,
BdrvCheckMode fix, bool *rebuild,
- uint16_t **refcount_table, int64_t *nb_clusters)
+ void **refcount_table, int64_t *nb_clusters)
{
BDRVQcowState *s = bs->opaque;
int64_t i, size;
@@ -1616,9 +1649,10 @@ resize_fail:
if (ret < 0) {
return ret;
}
- if ((*refcount_table)[cluster] != 1) {
+ if (s->get_refcount(*refcount_table, cluster) != 1) {
fprintf(stderr, "ERROR refcount block %" PRId64
- " refcount=%d\n", i, (*refcount_table)[cluster]);
+ " refcount=%" PRIu64 "\n", i,
+ s->get_refcount(*refcount_table, cluster));
res->corruptions++;
*rebuild = true;
}
@@ -1633,7 +1667,7 @@ resize_fail:
*/
static int calculate_refcounts(BlockDriverState *bs, BdrvCheckResult *res,
BdrvCheckMode fix, bool *rebuild,
- uint16_t **refcount_table, int64_t *nb_clusters)
+ void **refcount_table, int64_t *nb_clusters)
{
BDRVQcowState *s = bs->opaque;
int64_t i;
@@ -1697,7 +1731,7 @@ static int calculate_refcounts(BlockDriverState *bs,
BdrvCheckResult *res,
static void compare_refcounts(BlockDriverState *bs, BdrvCheckResult *res,
BdrvCheckMode fix, bool *rebuild,
int64_t *highest_cluster,
- uint16_t *refcount_table, int64_t nb_clusters)
+ void *refcount_table, int64_t nb_clusters)
{
BDRVQcowState *s = bs->opaque;
int64_t i, refcount1, refcount2;
@@ -1712,7 +1746,7 @@ static void compare_refcounts(BlockDriverState *bs,
BdrvCheckResult *res,
continue;
}
- refcount2 = refcount_table[i];
+ refcount2 = s->get_refcount(refcount_table, i);
if (refcount1 > 0 || refcount2 > 0) {
*highest_cluster = i;
@@ -1770,7 +1804,7 @@ static void compare_refcounts(BlockDriverState *bs,
BdrvCheckResult *res,
*/
static int64_t alloc_clusters_imrt(BlockDriverState *bs,
int cluster_count,
- uint16_t **refcount_table,
+ void **refcount_table,
int64_t *imrt_nb_clusters,
int64_t *first_free_cluster)
{
@@ -1787,7 +1821,7 @@ static int64_t alloc_clusters_imrt(BlockDriverState *bs,
contiguous_free_clusters < cluster_count;
cluster++)
{
- if (!(*refcount_table)[cluster]) {
+ if (!s->get_refcount(*refcount_table, cluster)) {
contiguous_free_clusters++;
if (first_gap) {
/* If this is the first free cluster found, update
@@ -1825,7 +1859,7 @@ static int64_t alloc_clusters_imrt(BlockDriverState *bs,
/* Go back to the first free cluster */
cluster -= contiguous_free_clusters;
for (i = 0; i < cluster_count; i++) {
- (*refcount_table)[cluster + i] = 1;
+ s->set_refcount(*refcount_table, cluster + i, 1);
}
return cluster << s->cluster_bits;
@@ -1841,7 +1875,7 @@ static int64_t alloc_clusters_imrt(BlockDriverState *bs,
*/
static int rebuild_refcount_structure(BlockDriverState *bs,
BdrvCheckResult *res,
- uint16_t **refcount_table,
+ void **refcount_table,
int64_t *nb_clusters)
{
BDRVQcowState *s = bs->opaque;
@@ -1849,8 +1883,8 @@ static int rebuild_refcount_structure(BlockDriverState
*bs,
int64_t refblock_offset, refblock_start, refblock_index;
uint32_t reftable_size = 0;
uint64_t *on_disk_reftable = NULL;
- uint16_t *on_disk_refblock;
- int i, ret = 0;
+ void *on_disk_refblock;
+ int ret = 0;
struct {
uint64_t reftable_offset;
uint32_t reftable_clusters;
@@ -1860,7 +1894,7 @@ static int rebuild_refcount_structure(BlockDriverState
*bs,
write_refblocks:
for (; cluster < *nb_clusters; cluster++) {
- if (!(*refcount_table)[cluster]) {
+ if (!s->get_refcount(*refcount_table, cluster)) {
continue;
}
@@ -1933,17 +1967,13 @@ write_refblocks:
goto fail;
}
- on_disk_refblock = qemu_blockalign0(bs->file, s->cluster_size);
- for (i = 0; i < s->refcount_block_size &&
- refblock_start + i < *nb_clusters; i++)
- {
- on_disk_refblock[i] =
- cpu_to_be16((*refcount_table)[refblock_start + i]);
- }
+ /* The size of *refcount_table is always cluster-aligned, therefore the
+ * write operation will not overflow */
+ on_disk_refblock = (void *)((uintptr_t)*refcount_table +
+ (refblock_index <<
s->refcount_block_bits));
ret = bdrv_write(bs->file, refblock_offset / BDRV_SECTOR_SIZE,
- (void *)on_disk_refblock, s->cluster_sectors);
- qemu_vfree(on_disk_refblock);
+ on_disk_refblock, s->cluster_sectors);
if (ret < 0) {
fprintf(stderr, "ERROR writing refblock: %s\n", strerror(-ret));
goto fail;
@@ -2038,7 +2068,7 @@ int qcow2_check_refcounts(BlockDriverState *bs,
BdrvCheckResult *res,
BDRVQcowState *s = bs->opaque;
BdrvCheckResult pre_compare_res;
int64_t size, highest_cluster, nb_clusters;
- uint16_t *refcount_table = NULL;
+ void *refcount_table = NULL;
bool rebuild = false;
int ret;
@@ -2087,7 +2117,7 @@ int qcow2_check_refcounts(BlockDriverState *bs,
BdrvCheckResult *res,
/* Because the old reftable has been exchanged for a new one the
* references have to be recalculated */
rebuild = false;
- memset(refcount_table, 0, nb_clusters * sizeof(uint16_t));
+ memset(refcount_table, 0, nb_clusters * s->refcount_bits / 8);
ret = calculate_refcounts(bs, res, 0, &rebuild, &refcount_table,
&nb_clusters);
if (ret < 0) {
diff --git a/block/qcow2.h b/block/qcow2.h
index 0f8eb15..1c63221 100644
--- a/block/qcow2.h
+++ b/block/qcow2.h
@@ -213,6 +213,11 @@ typedef struct Qcow2DiscardRegion {
QTAILQ_ENTRY(Qcow2DiscardRegion) next;
} Qcow2DiscardRegion;
+typedef uint64_t Qcow2GetRefcountFunc(const void *refcount_array,
+ uint64_t index);
+typedef void Qcow2SetRefcountFunc(void *refcount_array,
+ uint64_t index, uint64_t value);
+
typedef struct BDRVQcowState {
int cluster_bits;
int cluster_size;
@@ -261,6 +266,9 @@ typedef struct BDRVQcowState {
int refcount_bits;
uint64_t refcount_max;
+ Qcow2GetRefcountFunc *get_refcount;
+ Qcow2SetRefcountFunc *set_refcount;
+
bool discard_passthrough[QCOW2_DISCARD_MAX];
int overlap_check; /* bitmask of Qcow2MetadataOverlap values */
--
1.9.3
- [Qemu-devel] [PATCH v2 00/21] qcow2: Support refcount orders != 4, Max Reitz, 2014/11/14
- [Qemu-devel] [PATCH v2 01/21] qcow2: Add two new fields to BDRVQcowState, Max Reitz, 2014/11/14
- [Qemu-devel] [PATCH v2 02/21] qcow2: Add refcount_width to format-specific info, Max Reitz, 2014/11/14
- [Qemu-devel] [PATCH v2 03/21] qcow2: Use 64 bits for refcount values, Max Reitz, 2014/11/14
- [Qemu-devel] [PATCH v2 04/21] qcow2: Respect error in qcow2_alloc_bytes(), Max Reitz, 2014/11/14
- [Qemu-devel] [PATCH v2 05/21] qcow2: Refcount overflow and qcow2_alloc_bytes(), Max Reitz, 2014/11/14
- [Qemu-devel] [PATCH v2 06/21] qcow2: Helper for refcount array reallocation, Max Reitz, 2014/11/14
- [Qemu-devel] [PATCH v2 07/21] qcow2: Helper function for refcount modification,
Max Reitz <=
- [Qemu-devel] [PATCH v2 08/21] qcow2: More helpers for refcount modification, Max Reitz, 2014/11/14
- [Qemu-devel] [PATCH v2 09/21] qcow2: Open images with refcount order != 4, Max Reitz, 2014/11/14
- [Qemu-devel] [PATCH v2 11/21] iotests: Prepare for refcount_width option, Max Reitz, 2014/11/14
- [Qemu-devel] [PATCH v2 12/21] qcow2: Allow creation with refcount order != 4, Max Reitz, 2014/11/14