[Qemu-devel] [PATCH v9 06/20] dirty-bitmap: Change bdrv_dirty_bitmap_size() to report bytes

[Eric Blake <eblake@redhat.com>]

We're already reporting bytes for bdrv_dirty_bitmap_granularity();
mixing bytes and sectors in our return values is a recipe for
confusion.  A later cleanup will convert dirty bitmap internals
to be entirely byte-based, but in the meantime, we should report
the bitmap size in bytes.

The only external caller in qcow2-bitmap.c is temporarily more verbose
(because it is still using sector-based math), but will later be
switched to track progress by bytes instead of sectors.

Signed-off-by: Eric Blake <eblake@redhat.com>
Reviewed-by: John Snow <jsnow@redhat.com>
Reviewed-by: Kevin Wolf <kwolf@redhat.com>
Reviewed-by: Fam Zheng <famz@redhat.com>

---
v8: no change
v7: split external from internal change [Kevin], drop R-b
v6: no change
v5: fix bdrv_dirty_bitmap_truncate [John], drop R-b
v4: retitle from "Track size in bytes", rebase to persistent bitmaps,
round up when converting bytes to sectors
v3: no change
v2: tweak commit message, no code change
---
 block/dirty-bitmap.c |  2 +-
 block/qcow2-bitmap.c | 14 ++++++++------
 2 files changed, 9 insertions(+), 7 deletions(-)

diff --git a/block/dirty-bitmap.c b/block/dirty-bitmap.c
index ee164fb518..755555af32 100644
--- a/block/dirty-bitmap.c
+++ b/block/dirty-bitmap.c
@@ -175,7 +175,7 @@ void bdrv_release_meta_dirty_bitmap(BdrvDirtyBitmap *bitmap)

 int64_t bdrv_dirty_bitmap_size(const BdrvDirtyBitmap *bitmap)
 {
-    return bitmap->size;
+    return bitmap->size * BDRV_SECTOR_SIZE;
 }

 const char *bdrv_dirty_bitmap_name(const BdrvDirtyBitmap *bitmap)
diff --git a/block/qcow2-bitmap.c b/block/qcow2-bitmap.c
index b3ee4c794a..65122e9ae1 100644
--- a/block/qcow2-bitmap.c
+++ b/block/qcow2-bitmap.c
@@ -295,10 +295,11 @@ static int load_bitmap_data(BlockDriverState *bs,
     BDRVQcow2State *s = bs->opaque;
     uint64_t sector, sbc;
     uint64_t bm_size = bdrv_dirty_bitmap_size(bitmap);
+    uint64_t bm_sectors = DIV_ROUND_UP(bm_size, BDRV_SECTOR_SIZE);
     uint8_t *buf = NULL;
     uint64_t i, tab_size =
             size_to_clusters(s,
-                bdrv_dirty_bitmap_serialization_size(bitmap, 0, bm_size));
+                bdrv_dirty_bitmap_serialization_size(bitmap, 0, bm_sectors));

     if (tab_size != bitmap_table_size || tab_size > BME_MAX_TABLE_SIZE) {
         return -EINVAL;
@@ -307,7 +308,7 @@ static int load_bitmap_data(BlockDriverState *bs,
     buf = g_malloc(s->cluster_size);
     sbc = sectors_covered_by_bitmap_cluster(s, bitmap);
     for (i = 0, sector = 0; i < tab_size; ++i, sector += sbc) {
-        uint64_t count = MIN(bm_size - sector, sbc);
+        uint64_t count = MIN(bm_sectors - sector, sbc);
         uint64_t entry = bitmap_table[i];
         uint64_t offset = entry & BME_TABLE_ENTRY_OFFSET_MASK;

@@ -1077,13 +1078,14 @@ static uint64_t *store_bitmap_data(BlockDriverState *bs,
     int64_t sector;
     uint64_t sbc;
     uint64_t bm_size = bdrv_dirty_bitmap_size(bitmap);
+    uint64_t bm_sectors = DIV_ROUND_UP(bm_size, BDRV_SECTOR_SIZE);
     const char *bm_name = bdrv_dirty_bitmap_name(bitmap);
     uint8_t *buf = NULL;
     BdrvDirtyBitmapIter *dbi;
     uint64_t *tb;
     uint64_t tb_size =
             size_to_clusters(s,
-                bdrv_dirty_bitmap_serialization_size(bitmap, 0, bm_size));
+                bdrv_dirty_bitmap_serialization_size(bitmap, 0, bm_sectors));

     if (tb_size > BME_MAX_TABLE_SIZE ||
         tb_size * s->cluster_size > BME_MAX_PHYS_SIZE)
@@ -1101,7 +1103,7 @@ static uint64_t *store_bitmap_data(BlockDriverState *bs,
     dbi = bdrv_dirty_iter_new(bitmap, 0);
     buf = g_malloc(s->cluster_size);
     sbc = sectors_covered_by_bitmap_cluster(s, bitmap);
-    assert(DIV_ROUND_UP(bm_size, sbc) == tb_size);
+    assert(DIV_ROUND_UP(bm_sectors, sbc) == tb_size);

     while ((sector = bdrv_dirty_iter_next(dbi)) != -1) {
         uint64_t cluster = sector / sbc;
@@ -1109,7 +1111,7 @@ static uint64_t *store_bitmap_data(BlockDriverState *bs,
         int64_t off;

         sector = cluster * sbc;
-        end = MIN(bm_size, sector + sbc);
+        end = MIN(bm_sectors, sector + sbc);
         write_size =
             bdrv_dirty_bitmap_serialization_size(bitmap, sector, end - sector);
         assert(write_size <= s->cluster_size);
@@ -1141,7 +1143,7 @@ static uint64_t *store_bitmap_data(BlockDriverState *bs,
             goto fail;
         }

-        if (end >= bm_size) {
+        if (end >= bm_sectors) {
             break;
         }

-- 
2.13.5