block: Make bdrv_is_allocated_above() byte-based

We are gradually moving away from sector-based interfaces, towards
byte-based.  In the common case, allocation is unlikely to ever use
values that are not naturally sector-aligned, but it is possible
that byte-based values will let us be more precise about allocation
at the end of an unaligned file that can do byte-based access.

Changing the signature of the function to use int64_t *pnum ensures
that the compiler enforces that all callers are updated.  For now,
the io.c layer still assert()s that all callers are sector-aligned,
but that can be relaxed when a later patch implements byte-based
block status.  Therefore, for the most part this patch is just the
addition of scaling at the callers followed by inverse scaling at
bdrv_is_allocated().  But some code, particularly stream_run(),
gets a lot simpler because it no longer has to mess with sectors.
Leave comments where we can further simplify by switching to
byte-based iterations, once later patches eliminate the need for
sector-aligned operations.

For ease of review, bdrv_is_allocated() was tackled separately.

Signed-off-by: Eric Blake <eblake@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>

1 files changed, 8 insertions, 12 deletions

diff --git a/block/commit.c b/block/commit.c
index 241aa95..774a8a5 100644
--- a/block/commit.c
+++ b/block/commit.c
@@ -146,7 +146,7 @@ static void coroutine_fn commit_run(void *opaque)
     int64_t offset;
     uint64_t delay_ns = 0;
     int ret = 0;
-    int n = 0; /* sectors */
+    int64_t n = 0; /* bytes */
     void *buf = NULL;
     int bytes_written = 0;
     int64_t base_len;
@@ -171,7 +171,7 @@ static void coroutine_fn commit_run(void *opaque)
 
     buf = blk_blockalign(s->top, COMMIT_BUFFER_SIZE);
 
-    for (offset = 0; offset < s->common.len; offset += n * BDRV_SECTOR_SIZE) {
+    for (offset = 0; offset < s->common.len; offset += n) {
         bool copy;
 
         /* Note that even when no rate limit is applied we need to yield
@@ -183,15 +183,12 @@ static void coroutine_fn commit_run(void *opaque)
         }
         /* Copy if allocated above the base */
         ret = bdrv_is_allocated_above(blk_bs(s->top), blk_bs(s->base),
-                                      offset / BDRV_SECTOR_SIZE,
-                                      COMMIT_BUFFER_SIZE / BDRV_SECTOR_SIZE,
-                                      &n);
+                                      offset, COMMIT_BUFFER_SIZE, &n);
         copy = (ret == 1);
-        trace_commit_one_iteration(s, offset, n * BDRV_SECTOR_SIZE, ret);
+        trace_commit_one_iteration(s, offset, n, ret);
         if (copy) {
-            ret = commit_populate(s->top, s->base, offset,
-                                  n * BDRV_SECTOR_SIZE, buf);
-            bytes_written += n * BDRV_SECTOR_SIZE;
+            ret = commit_populate(s->top, s->base, offset, n, buf);
+            bytes_written += n;
         }
         if (ret < 0) {
             BlockErrorAction action =
@@ -204,11 +201,10 @@ static void coroutine_fn commit_run(void *opaque)
             }
         }
         /* Publish progress */
-        s->common.offset += n * BDRV_SECTOR_SIZE;
+        s->common.offset += n;
 
         if (copy && s->common.speed) {
-            delay_ns = ratelimit_calculate_delay(&s->limit,
-                                                 n * BDRV_SECTOR_SIZE);
+            delay_ns = ratelimit_calculate_delay(&s->limit, n);
         }
     }