@@ -25,6 +25,11 @@
* THE SOFTWARE.
*/
+#include "qemu/osdep.h"
+
+#include "block/block_int.h"
+#include "block/qcow2.h"
+
/* NOTICE: BME here means Bitmaps Extension and used as a namespace for
* _internal_ constants. Please do not use this _internal_ abbreviation for
* other needs and/or outside of this file. */
@@ -45,3 +50,163 @@
typedef enum BitmapType {
BT_DIRTY_TRACKING_BITMAP = 1
} BitmapType;
+
+void qcow2_free_bitmaps(BlockDriverState *bs)
+{
+ BDRVQcow2State *s = bs->opaque;
+ int i;
+
+ for (i = 0; i < s->nb_bitmaps; i++) {
+ g_free(s->bitmaps[i].name);
+ }
+ g_free(s->bitmaps);
+ s->bitmaps = NULL;
+ s->nb_bitmaps = 0;
+
+ g_free(s->bitmap_directory);
+ s->bitmap_directory = NULL;
+}
+
+static void bitmap_header_to_cpu(QCow2BitmapHeader *h)
+{
+ be64_to_cpus(&h->bitmap_table_offset);
+ be32_to_cpus(&h->bitmap_table_size);
+ be32_to_cpus(&h->flags);
+ be16_to_cpus(&h->name_size);
+ be32_to_cpus(&h->extra_data_size);
+}
+
+static int calc_dir_entry_size(size_t name_size)
+{
+ return align_offset(sizeof(QCow2BitmapHeader) + name_size, 8);
+}
+
+static int dir_entry_size(QCow2BitmapHeader *h)
+{
+ return calc_dir_entry_size(h->name_size);
+}
+
+static int check_constraints(QCow2BitmapHeader *h, int cluster_size,
+ uint64_t disk_size)
+{
+ uint64_t phys_bitmap_bytes =
+ (uint64_t)h->bitmap_table_size * cluster_size;
+ uint64_t max_virtual_bits = (phys_bitmap_bytes * 8) << h->granularity_bits;
+
+ int fail =
+ (h->bitmap_table_offset % cluster_size) ||
+ (h->bitmap_table_size > BME_MAX_TABLE_SIZE) ||
+ (phys_bitmap_bytes > BME_MAX_PHYS_SIZE) ||
+ (disk_size > max_virtual_bits) ||
+ (h->granularity_bits > BME_MAX_GRANULARITY_BITS) ||
+ (h->granularity_bits < BME_MIN_GRANULARITY_BITS) ||
+ (h->flags & BME_RESERVED_FLAGS) ||
+ (h->name_size > BME_MAX_NAME_SIZE) ||
+ (h->type != BT_DIRTY_TRACKING_BITMAP);
+
+ return fail ? -EINVAL : 0;
+}
+
+static int directory_read(BlockDriverState *bs, Error **errp)
+{
+ int ret;
+ BDRVQcow2State *s = bs->opaque;
+ QCow2Bitmap *bm, *end;
+ int64_t nb_sectors = bdrv_nb_sectors(bs);
+ size_t offset;
+
+ if (nb_sectors < 0) {
+ error_setg(errp, "Can't calculate number of disk sectors.");
+ return nb_sectors;
+ }
+
+ if (s->bitmap_directory != NULL) {
+ /* already read */
+ error_setg(errp, "Try read bitmaps, when they are already read.");
+ return -EEXIST;
+ }
+
+ s->bitmap_directory = g_try_malloc0(s->bitmap_directory_size);
+ if (s->bitmap_directory == NULL) {
+ error_setg(errp, "Can't allocate space for bitmap directory.");
+ return -ENOMEM;
+ }
+
+ ret = bdrv_pread(bs->file->bs,
+ s->bitmap_directory_offset,
+ s->bitmap_directory,
+ s->bitmap_directory_size);
+ if (ret < 0) {
+ error_setg(errp, "Can't read bitmap directory.");
+ goto fail;
+ }
+
+ offset = 0;
+ end = s->bitmaps + s->nb_bitmaps;
+ for (bm = s->bitmaps; bm < end; ++bm) {
+ QCow2BitmapHeader *h =
+ (QCow2BitmapHeader *)(s->bitmap_directory + offset);
+
+ if (offset >= s->bitmap_directory_size) {
+ error_setg(errp, "Broken bitmap directory.");
+ goto fail;
+ }
+
+ bitmap_header_to_cpu(h);
+
+ ret = check_constraints(h, s->cluster_size,
+ nb_sectors << BDRV_SECTOR_BITS);
+ if (ret < 0) {
+ error_setg(errp, "Bitmap doesn't satisfy the constraints.");
+ goto fail;
+ }
+
+ bm->offset = offset;
+ bm->name = g_strndup((char *)(h + 1), h->name_size);
+
+ offset += dir_entry_size(h);
+ }
+ return 0;
+
+fail:
+ g_free(s->bitmap_directory);
+ s->bitmap_directory = NULL;
+
+ return ret;
+}
+
+int qcow2_read_bitmaps(BlockDriverState *bs, Error **errp)
+{
+ int ret;
+ BDRVQcow2State *s = bs->opaque;
+
+ if (s->bitmap_directory != NULL || s->bitmaps != NULL) {
+ /* already read */
+ error_setg(errp, "Try read bitmaps, when they are already read.");
+ return -EEXIST;
+ }
+
+ if (s->nb_bitmaps == 0) {
+ /* No bitmaps - nothing to do */
+ return 0;
+ }
+
+ s->bitmaps = g_try_new0(QCow2Bitmap, s->nb_bitmaps);
+ if (s->bitmaps == NULL) {
+ error_setg(errp, "Can't allocate space for qcow2 bitmaps.");
+ ret = -ENOMEM;
+ goto fail;
+ }
+
+ ret = directory_read(bs, errp);
+ if (ret < 0) {
+ goto fail;
+ }
+
+ return 0;
+
+fail:
+ qcow2_free_bitmaps(bs);
+
+ return ret;
+}
@@ -297,6 +297,12 @@ typedef struct BDRVQcow2State {
unsigned int nb_snapshots;
QCowSnapshot *snapshots;
+ uint64_t bitmap_directory_offset;
+ uint64_t bitmap_directory_size;
+ uint8_t *bitmap_directory;
+ unsigned int nb_bitmaps;
+ QCow2Bitmap *bitmaps;
+
int flags;
int qcow_version;
bool use_lazy_refcounts;
@@ -610,6 +616,10 @@ int qcow2_snapshot_load_tmp(BlockDriverState *bs,
void qcow2_free_snapshots(BlockDriverState *bs);
int qcow2_read_snapshots(BlockDriverState *bs);
+/* qcow2-dirty-bitmap.c functions */
+void qcow2_free_bitmaps(BlockDriverState *bs);
+int qcow2_read_bitmaps(BlockDriverState *bs, Error **errp);
+
/* qcow2-cache.c functions */
Qcow2Cache *qcow2_cache_create(BlockDriverState *bs, int num_tables);
int qcow2_cache_destroy(BlockDriverState* bs, Qcow2Cache *c);
Adds qcow2_read_bitmaps, reading bitmap directory as specified in docs/specs/qcow2.txt Signed-off-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com> --- block/qcow2-dirty-bitmap.c | 165 +++++++++++++++++++++++++++++++++++++++++++++ block/qcow2.h | 10 +++ 2 files changed, 175 insertions(+)