dirty-bitmap: improve bdrv_dirty_bitmap_next_zero
Add bytes parameter to the function, to limit searched range.
Signed-off-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
diff --git a/block/backup.c b/block/backup.c
index b829b25..9ffce5c 100644
--- a/block/backup.c
+++ b/block/backup.c
@@ -422,7 +422,8 @@
break;
}
- offset = bdrv_dirty_bitmap_next_zero(job->sync_bitmap, offset);
+ offset = bdrv_dirty_bitmap_next_zero(job->sync_bitmap, offset,
+ UINT64_MAX);
if (offset == -1) {
hbitmap_set(job->copy_bitmap, cluster, end - cluster);
break;
diff --git a/block/dirty-bitmap.c b/block/dirty-bitmap.c
index 6b68839..b162f4a 100644
--- a/block/dirty-bitmap.c
+++ b/block/dirty-bitmap.c
@@ -781,9 +781,10 @@
return hbitmap_sha256(bitmap->bitmap, errp);
}
-int64_t bdrv_dirty_bitmap_next_zero(BdrvDirtyBitmap *bitmap, uint64_t offset)
+int64_t bdrv_dirty_bitmap_next_zero(BdrvDirtyBitmap *bitmap, uint64_t offset,
+ uint64_t bytes)
{
- return hbitmap_next_zero(bitmap->bitmap, offset);
+ return hbitmap_next_zero(bitmap->bitmap, offset, bytes);
}
void bdrv_merge_dirty_bitmap(BdrvDirtyBitmap *dest, const BdrvDirtyBitmap *src,
diff --git a/include/block/dirty-bitmap.h b/include/block/dirty-bitmap.h
index 8f38a3d..102ccdd 100644
--- a/include/block/dirty-bitmap.h
+++ b/include/block/dirty-bitmap.h
@@ -99,7 +99,8 @@
BdrvDirtyBitmap *bdrv_dirty_bitmap_next(BlockDriverState *bs,
BdrvDirtyBitmap *bitmap);
char *bdrv_dirty_bitmap_sha256(const BdrvDirtyBitmap *bitmap, Error **errp);
-int64_t bdrv_dirty_bitmap_next_zero(BdrvDirtyBitmap *bitmap, uint64_t start);
+int64_t bdrv_dirty_bitmap_next_zero(BdrvDirtyBitmap *bitmap, uint64_t offset,
+ uint64_t bytes);
BdrvDirtyBitmap *bdrv_reclaim_dirty_bitmap_locked(BlockDriverState *bs,
BdrvDirtyBitmap *bitmap,
Error **errp);
diff --git a/include/qemu/hbitmap.h b/include/qemu/hbitmap.h
index a7cb780..1359755 100644
--- a/include/qemu/hbitmap.h
+++ b/include/qemu/hbitmap.h
@@ -300,12 +300,16 @@
unsigned long hbitmap_iter_skip_words(HBitmapIter *hbi);
/* hbitmap_next_zero:
+ *
+ * Find next not dirty bit within selected range. If not found, return -1.
+ *
* @hb: The HBitmap to operate on
* @start: The bit to start from.
- *
- * Find next not dirty bit.
+ * @count: Number of bits to proceed. If @start+@count > bitmap size, the whole
+ * bitmap is looked through. You can use UINT64_MAX as @count to search up to
+ * the bitmap end.
*/
-int64_t hbitmap_next_zero(const HBitmap *hb, uint64_t start);
+int64_t hbitmap_next_zero(const HBitmap *hb, uint64_t start, uint64_t count);
/* hbitmap_create_meta:
* Create a "meta" hbitmap to track dirtiness of the bits in this HBitmap.
diff --git a/nbd/server.c b/nbd/server.c
index e8c5660..6b13601 100644
--- a/nbd/server.c
+++ b/nbd/server.c
@@ -2014,7 +2014,7 @@
bool next_dirty = !dirty;
if (dirty) {
- end = bdrv_dirty_bitmap_next_zero(bitmap, begin);
+ end = bdrv_dirty_bitmap_next_zero(bitmap, begin, UINT64_MAX);
} else {
bdrv_set_dirty_iter(it, begin);
end = bdrv_dirty_iter_next(it);
diff --git a/tests/test-hbitmap.c b/tests/test-hbitmap.c
index 5e67ac1..b04a45a 100644
--- a/tests/test-hbitmap.c
+++ b/tests/test-hbitmap.c
@@ -939,7 +939,7 @@
static void test_hbitmap_next_zero_check(TestHBitmapData *data, int64_t start)
{
- int64_t ret1 = hbitmap_next_zero(data->hb, start);
+ int64_t ret1 = hbitmap_next_zero(data->hb, start, UINT64_MAX);
int64_t ret2 = start;
for ( ; ret2 < data->size && hbitmap_get(data->hb, ret2); ret2++) {
;
diff --git a/util/hbitmap.c b/util/hbitmap.c
index 8d402c5..09b3719 100644
--- a/util/hbitmap.c
+++ b/util/hbitmap.c
@@ -53,6 +53,9 @@
*/
struct HBitmap {
+ /* Size of the bitmap, as requested in hbitmap_alloc. */
+ uint64_t orig_size;
+
/* Number of total bits in the bottom level. */
uint64_t size;
@@ -192,16 +195,28 @@
}
}
-int64_t hbitmap_next_zero(const HBitmap *hb, uint64_t start)
+int64_t hbitmap_next_zero(const HBitmap *hb, uint64_t start, uint64_t count)
{
size_t pos = (start >> hb->granularity) >> BITS_PER_LEVEL;
unsigned long *last_lev = hb->levels[HBITMAP_LEVELS - 1];
- uint64_t sz = hb->sizes[HBITMAP_LEVELS - 1];
unsigned long cur = last_lev[pos];
- unsigned start_bit_offset =
- (start >> hb->granularity) & (BITS_PER_LONG - 1);
+ unsigned start_bit_offset;
+ uint64_t end_bit, sz;
int64_t res;
+ if (start >= hb->orig_size || count == 0) {
+ return -1;
+ }
+
+ end_bit = count > hb->orig_size - start ?
+ hb->size :
+ ((start + count - 1) >> hb->granularity) + 1;
+ sz = (end_bit + BITS_PER_LONG - 1) >> BITS_PER_LEVEL;
+
+ /* There may be some zero bits in @cur before @start. We are not interested
+ * in them, let's set them.
+ */
+ start_bit_offset = (start >> hb->granularity) & (BITS_PER_LONG - 1);
cur |= (1UL << start_bit_offset) - 1;
assert((start >> hb->granularity) < hb->size);
@@ -218,7 +233,7 @@
}
res = (pos << BITS_PER_LEVEL) + ctol(cur);
- if (res >= hb->size) {
+ if (res >= end_bit) {
return -1;
}
@@ -652,6 +667,8 @@
HBitmap *hb = g_new0(struct HBitmap, 1);
unsigned i;
+ hb->orig_size = size;
+
assert(granularity >= 0 && granularity < 64);
size = (size + (1ULL << granularity) - 1) >> granularity;
assert(size <= ((uint64_t)1 << HBITMAP_LOG_MAX_SIZE));
