We are gradually converting to byte-based interfaces, as they are
easier to reason about than sector-based. Change the internal
loop iteration of streaming to track by bytes instead of sectors
(although we are still guaranteed that we iterate by steps that
are sector-aligned).
Signed-off-by: Eric Blake <ebl...@redhat.com>
Reviewed-by: John Snow <js...@redhat.com>
---
v2: no change
---
block/stream.c | 24 ++++++++++--------------
1 file changed, 10 insertions(+), 14 deletions(-)
diff --git a/block/stream.c b/block/stream.c
index 5acef6d..3ed4fef 100644
--- a/block/stream.c
+++ b/block/stream.c
@@ -108,12 +108,11 @@ static void coroutine_fn stream_run(void *opaque)
BlockBackend *blk = s->common.blk;
BlockDriverState *bs = blk_bs(blk);
BlockDriverState *base = s->base;
- int64_t sector_num = 0;
- int64_t end = -1;
+ int64_t offset = 0;
uint64_t delay_ns = 0;
int error = 0;
int ret = 0;
- int n = 0;
+ int n = 0; /* sectors */
void *buf;
if (!bs->backing) {
@@ -126,7 +125,6 @@ static void coroutine_fn stream_run(void *opaque)
goto out;
}
- end = s->common.len >> BDRV_SECTOR_BITS;
buf = qemu_blockalign(bs, STREAM_BUFFER_SIZE);
/* Turn on copy-on-read for the whole block device so that guest read
@@ -138,7 +136,7 @@ static void coroutine_fn stream_run(void *opaque)
bdrv_enable_copy_on_read(bs);
}
- for (sector_num = 0; sector_num < end; sector_num += n) {
+ for ( ; offset < s->common.len; offset += n * BDRV_SECTOR_SIZE) {
bool copy;
/* Note that even when no rate limit is applied we need to yield
@@ -151,28 +149,26 @@ static void coroutine_fn stream_run(void *opaque)
copy = false;
- ret = bdrv_is_allocated(bs, sector_num,
+ ret = bdrv_is_allocated(bs, offset / BDRV_SECTOR_SIZE,
STREAM_BUFFER_SIZE / BDRV_SECTOR_SIZE, &n);
if (ret == 1) {
/* Allocated in the top, no need to copy. */
} else if (ret >= 0) {
/* Copy if allocated in the intermediate images. Limit to the
- * known-unallocated area [sector_num, sector_num+n). */
+ * known-unallocated area [offset, offset+n*BDRV_SECTOR_SIZE). */
ret = bdrv_is_allocated_above(backing_bs(bs), base,
- sector_num, n, &n);
+ offset / BDRV_SECTOR_SIZE, n, &n);
/* Finish early if end of backing file has been reached */
if (ret == 0 && n == 0) {
- n = end - sector_num;
+ n = (s->common.len - offset) / BDRV_SECTOR_SIZE;
}
copy = (ret == 1);
}
- trace_stream_one_iteration(s, sector_num * BDRV_SECTOR_SIZE,
- n * BDRV_SECTOR_SIZE, ret);
+ trace_stream_one_iteration(s, offset, n * BDRV_SECTOR_SIZE, ret);
if (copy) {
- ret = stream_populate(blk, sector_num * BDRV_SECTOR_SIZE,
- n * BDRV_SECTOR_SIZE, buf);
+ ret = stream_populate(blk, offset, n * BDRV_SECTOR_SIZE, buf);
}
if (ret < 0) {
BlockErrorAction action =
@@ -211,7 +207,7 @@ out:
/* Modify backing chain and close BDSes in main loop */
data = g_malloc(sizeof(*data));
data->ret = ret;
- data->reached_end = sector_num == end;
+ data->reached_end = offset == s->common.len;
block_job_defer_to_main_loop(&s->common, stream_complete, data);
}
--
2.9.3
