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authorEric Blake <eblake@redhat.com>2017-09-25 09:55:22 -0500
committerKevin Wolf <kwolf@redhat.com>2017-10-06 16:28:58 +0200
commitb85ee45334585c49c5489a303336df119408763a (patch)
tree91a06c6147dcbe0cc416db83e5d0085361766754
parent23ca459a455c83ffadb03ab1eedf0b6cff62bfeb (diff)
qcow2: Switch qcow2_measure() to byte-based iteration
This is new code, but it is easier to read if it makes passes over the image using bytes rather than sectors (and will get easier in the future when bdrv_get_block_status is converted to byte-based). 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> Signed-off-by: Kevin Wolf <kwolf@redhat.com>
-rw-r--r--block/qcow2.c22
1 files changed, 10 insertions, 12 deletions
diff --git a/block/qcow2.c b/block/qcow2.c
index 970006fc1d..b8da8ca105 100644
--- a/block/qcow2.c
+++ b/block/qcow2.c
@@ -3673,20 +3673,19 @@ static BlockMeasureInfo *qcow2_measure(QemuOpts *opts, BlockDriverState *in_bs,
*/
required = virtual_size;
} else {
- int cluster_sectors = cluster_size / BDRV_SECTOR_SIZE;
- int64_t sector_num;
+ int64_t offset;
int pnum = 0;
- for (sector_num = 0;
- sector_num < ssize / BDRV_SECTOR_SIZE;
- sector_num += pnum) {
- int nb_sectors = MIN(ssize / BDRV_SECTOR_SIZE - sector_num,
- BDRV_REQUEST_MAX_SECTORS);
+ for (offset = 0; offset < ssize;
+ offset += pnum * BDRV_SECTOR_SIZE) {
+ int nb_sectors = MIN(ssize - offset,
+ BDRV_REQUEST_MAX_BYTES) / BDRV_SECTOR_SIZE;
BlockDriverState *file;
int64_t ret;
ret = bdrv_get_block_status_above(in_bs, NULL,
- sector_num, nb_sectors,
+ offset >> BDRV_SECTOR_BITS,
+ nb_sectors,
&pnum, &file);
if (ret < 0) {
error_setg_errno(&local_err, -ret,
@@ -3699,12 +3698,11 @@ static BlockMeasureInfo *qcow2_measure(QemuOpts *opts, BlockDriverState *in_bs,
} else if ((ret & (BDRV_BLOCK_DATA | BDRV_BLOCK_ALLOCATED)) ==
(BDRV_BLOCK_DATA | BDRV_BLOCK_ALLOCATED)) {
/* Extend pnum to end of cluster for next iteration */
- pnum = ROUND_UP(sector_num + pnum, cluster_sectors) -
- sector_num;
+ pnum = (ROUND_UP(offset + pnum * BDRV_SECTOR_SIZE,
+ cluster_size) - offset) >> BDRV_SECTOR_BITS;
/* Count clusters we've seen */
- required += (sector_num % cluster_sectors + pnum) *
- BDRV_SECTOR_SIZE;
+ required += offset % cluster_size + pnum * BDRV_SECTOR_SIZE;
}
}
}