Adds qcow2_read_dirty_bitmaps, reading Dirty Bitmap Directory as
specified in docs/specs/qcow2.txt
Signed-off-by: Vladimir Sementsov-Ogievskiy <vsement...@virtuozzo.com>
---
block/qcow2-dirty-bitmap.c | 155 +++++++++++++++++++++++++++++++++++++++++++++
block/qcow2.h | 10 +++
2 files changed, 165 insertions(+)
diff --git a/block/qcow2-dirty-bitmap.c b/block/qcow2-dirty-bitmap.c
index fd4e0ef..1260d1d 100644
--- a/block/qcow2-dirty-bitmap.c
+++ b/block/qcow2-dirty-bitmap.c
@@ -25,6 +25,9 @@
* THE SOFTWARE.
*/
+#include "block/block_int.h"
+#include "block/qcow2.h"
+
/* NOTICE: DBM here means Dirty Bitmap and used as a namespace for _internal_
* constants. Please do not use this _internal_ abbreviation for other needs
* and/or outside of this file. */
@@ -40,3 +43,155 @@
/* bits [0, 8] U [56, 63] are reserved */
#define DBM_TABLE_ENTRY_RESERVED_MASK 0xff000000000001ff
+
+void qcow2_free_dirty_bitmaps(BlockDriverState *bs)
+{
+ BDRVQcowState *s = bs->opaque;
+ int i;
+
+ for (i = 0; i < s->nb_dirty_bitmaps; i++) {
+ g_free(s->dirty_bitmaps[i].name);
+ }
+ g_free(s->dirty_bitmaps);
+ s->dirty_bitmaps = NULL;
+ s->nb_dirty_bitmaps = 0;
+
+ g_free(s->dirty_bitmap_directory);
+ s->dirty_bitmap_directory = NULL;
+}
+
+static void bitmap_header_to_cpu(QCowDirtyBitmapHeader *h)
+{
+ be64_to_cpus(&h->dirty_bitmap_table_offset);
+ be64_to_cpus(&h->nb_virtual_bits);
+ be32_to_cpus(&h->dirty_bitmap_table_size);
+ be32_to_cpus(&h->granularity_bits);
+ be32_to_cpus(&h->flags);
+ be16_to_cpus(&h->name_size);
+}
+
+static int calc_dir_entry_size(size_t name_size)
+{
+ return align_offset(sizeof(QCowDirtyBitmapHeader) + name_size, 8);
+}
+
+static int dir_entry_size(QCowDirtyBitmapHeader *h)
+{
+ return calc_dir_entry_size(h->name_size);
+}
+
+static int check_constraints(int cluster_size,
+ QCowDirtyBitmapHeader *h)
+{
+ uint64_t phys_bitmap_bytes =
+ (uint64_t)h->dirty_bitmap_table_size * cluster_size;
+ uint64_t max_virtual_bits = (phys_bitmap_bytes * 8) << h->granularity_bits;
+
+ int fail =
+ (h->dirty_bitmap_table_offset % cluster_size) ||
+ (h->dirty_bitmap_table_size > DBM_MAX_TABLE_SIZE) ||
+ (phys_bitmap_bytes > DBM_MAX_PHYS_SIZE) ||
+ (h->nb_virtual_bits > max_virtual_bits) ||
+ (h->granularity_bits > DBM_MAX_GRANULARITY_BITS) ||
+ (h->flags & DBM_RESERVED_FLAGS) ||
+ (h->name_size > DBM_MAX_NAME_SIZE);
+
+ return fail ? -EINVAL : 0;
+}
+
+static int directory_read(BlockDriverState *bs)
+{
+ int ret;
+ BDRVQcowState *s = bs->opaque;
+ uint8_t *entry, *end;
+
+ if (s->dirty_bitmap_directory != NULL) {
+ /* already read */
+ return -EEXIST;
+ }
+
+ s->dirty_bitmap_directory = g_try_malloc0(s->dirty_bitmap_directory_size);
+ if (s->dirty_bitmap_directory == NULL) {
+ return -ENOMEM;
+ }
+
+ ret = bdrv_pread(bs->file,
+ s->dirty_bitmap_directory_offset,
+ s->dirty_bitmap_directory,
+ s->dirty_bitmap_directory_size);
+ if (ret < 0) {
+ goto fail;
+ }
+
+ entry = s->dirty_bitmap_directory;
+ end = s->dirty_bitmap_directory + s->dirty_bitmap_directory_size;
+ while (entry < end) {
+ QCowDirtyBitmapHeader *h = (QCowDirtyBitmapHeader *)entry;
+ bitmap_header_to_cpu(h);
+
+ ret = check_constraints(s->cluster_size, h);
+ if (ret < 0) {
+ goto fail;
+ }
+
+ entry += dir_entry_size(h);
+ }
+
+ return 0;
+
+fail:
+ g_free(s->dirty_bitmap_directory);
+ s->dirty_bitmap_directory = NULL;
+
+ return ret;
+}
+
+int qcow2_read_dirty_bitmaps(BlockDriverState *bs)
+{
+ int ret;
+ BDRVQcowState *s = bs->opaque;
+ size_t offset;
+ QCowDirtyBitmap *bm, *end;
+
+ if (s->dirty_bitmap_directory != NULL || s->dirty_bitmaps != NULL) {
+ /* already read */
+ return -EEXIST;
+ }
+
+ if (s->nb_dirty_bitmaps == 0) {
+ /* No bitmaps - nothing to do */
+ return 0;
+ }
+
+ ret = directory_read(bs);
+ if (ret < 0) {
+ return ret;
+ }
+
+ s->dirty_bitmaps = g_try_new0(QCowDirtyBitmap, s->nb_dirty_bitmaps);
+ if (s->dirty_bitmaps == NULL) {
+ ret = -ENOMEM;
+ goto out;
+ }
+
+ offset = 0;
+ end = s->dirty_bitmaps + s->nb_dirty_bitmaps;
+ for (bm = s->dirty_bitmaps; bm < end; ++bm) {
+ QCowDirtyBitmapHeader *h =
+ (QCowDirtyBitmapHeader *)(s->dirty_bitmap_directory + offset);
+
+ bm->offset = offset;
+ bm->name = g_malloc(h->name_size + 1);
+ memcpy(bm->name, h + 1, h->name_size);
+ bm->name[h->name_size] = '\0';
+
+ offset += dir_entry_size(h);
+ }
+ ret = 0;
+
+out:
+ if (ret < 0) {
+ qcow2_free_dirty_bitmaps(bs);
+ }
+ return ret;
+}
diff --git a/block/qcow2.h b/block/qcow2.h
index a2a5d4a..5016fa1 100644
--- a/block/qcow2.h
+++ b/block/qcow2.h
@@ -288,6 +288,12 @@ typedef struct BDRVQcowState {
unsigned int nb_snapshots;
QCowSnapshot *snapshots;
+ uint64_t dirty_bitmap_directory_offset;
+ size_t dirty_bitmap_directory_size;
+ uint8_t *dirty_bitmap_directory;
+ unsigned int nb_dirty_bitmaps;
+ QCowDirtyBitmap *dirty_bitmaps;
+
int flags;
int qcow_version;
bool use_lazy_refcounts;
@@ -598,6 +604,10 @@ 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_dirty_bitmaps(BlockDriverState *bs);
+int qcow2_read_dirty_bitmaps(BlockDriverState *bs);
+
/* qcow2-cache.c functions */
Qcow2Cache *qcow2_cache_create(BlockDriverState *bs, int num_tables);
int qcow2_cache_destroy(BlockDriverState* bs, Qcow2Cache *c);
--
2.1.4
