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qcow2: Switch load_bitmap_data() to byte-based iteration 

Now that we have adjusted the majority of the calls this function
makes to be byte-based, it is easier to read the code if it makes
passes over the image using bytes rather than sectors.

Signed-off-by: Eric Blake <eblake@redhat.com>
Reviewed-by: John Snow <jsnow@redhat.com>
Reviewed-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
Reviewed-by: Kevin Wolf <kwolf@redhat.com>
Reviewed-by: Fam Zheng <famz@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
This commit is contained in:
Eric Blake 2017-09-25 09:55:23 -05:00 committed by Kevin Wolf
parent b85ee45334
commit ab94db6f76
1 changed files with 8 additions and 14 deletions
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22
block/qcow2-bitmap.c
View File

@ -291,9 +291,8 @@ static int load_bitmap_data(BlockDriverState *bs,
{
int ret = 0;
BDRVQcow2State *s = bs->opaque;
uint64_t sector, limit, sbc;
uint64_t offset, limit;
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,
@ -305,32 +304,27 @@ static int load_bitmap_data(BlockDriverState *bs,
buf = g_malloc(s->cluster_size);
limit = bytes_covered_by_bitmap_cluster(s, bitmap);
sbc = limit >> BDRV_SECTOR_BITS;
for (i = 0, sector = 0; i < tab_size; ++i, sector += sbc) {
uint64_t count = MIN(bm_sectors - sector, sbc);
for (i = 0, offset = 0; i < tab_size; ++i, offset += limit) {
uint64_t count = MIN(bm_size - offset, limit);
uint64_t entry = bitmap_table[i];
uint64_t offset = entry & BME_TABLE_ENTRY_OFFSET_MASK;
uint64_t data_offset = entry & BME_TABLE_ENTRY_OFFSET_MASK;
assert(check_table_entry(entry, s->cluster_size) == 0);
if (offset == 0) {
if (data_offset == 0) {
if (entry & BME_TABLE_ENTRY_FLAG_ALL_ONES) {
bdrv_dirty_bitmap_deserialize_ones(bitmap,
sector * BDRV_SECTOR_SIZE,
count * BDRV_SECTOR_SIZE,
bdrv_dirty_bitmap_deserialize_ones(bitmap, offset, count,
false);
} else {
/* No need to deserialize zeros because the dirty bitmap is
* already cleared */
}
} else {
ret = bdrv_pread(bs->file, offset, buf, s->cluster_size);
ret = bdrv_pread(bs->file, data_offset, buf, s->cluster_size);
if (ret < 0) {
goto finish;
}
bdrv_dirty_bitmap_deserialize_part(bitmap, buf,
sector * BDRV_SECTOR_SIZE,
count * BDRV_SECTOR_SIZE,
bdrv_dirty_bitmap_deserialize_part(bitmap, buf, offset, count,
false);
}
}