[PATCH for-5.0? v3] qemu-img: Report convert errors by bytes, not sectors

[Eric Blake <eblake@redhat.com>]

Various qemu-img commands are inconsistent on whether they report
status/errors in terms of bytes or sector offsets.  The latter is
confusing (especially as more places move to 4k block sizes), so let's
switch everything to just use bytes everywhere.  One iotest is
impacted.

Signed-off-by: Eric Blake <eblake@redhat.com>
Reviewed-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
---

v3: Fix affected iotest [patchew]

 qemu-img.c                 | 8 ++++----
 tests/qemu-iotests/244.out | 2 +-
 2 files changed, 5 insertions(+), 5 deletions(-)

diff --git a/qemu-img.c b/qemu-img.c
index b167376bd72e..821cbf610e5f 100644
--- a/qemu-img.c
+++ b/qemu-img.c
@@ -1924,8 +1924,8 @@ retry:
         if (status == BLK_DATA && !copy_range) {
             ret = convert_co_read(s, sector_num, n, buf);
             if (ret < 0) {
-                error_report("error while reading sector %" PRId64
-                             ": %s", sector_num, strerror(-ret));
+                error_report("error while reading at byte %lld: %s",
+                             sector_num * BDRV_SECTOR_SIZE, strerror(-ret));
                 s->ret = ret;
             }
         } else if (!s->min_sparse && status == BLK_ZERO) {
@@ -1953,8 +1953,8 @@ retry:
                 ret = convert_co_write(s, sector_num, n, buf, status);
             }
             if (ret < 0) {
-                error_report("error while writing sector %" PRId64
-                             ": %s", sector_num, strerror(-ret));
+                error_report("error while writing at byte %lld: %s",
+                             sector_num * BDRV_SECTOR_SIZE, strerror(-ret));
                 s->ret = ret;
             }
         }
diff --git a/tests/qemu-iotests/244.out b/tests/qemu-iotests/244.out
index e6f4dc79934b..56329deb4b9f 100644
--- a/tests/qemu-iotests/244.out
+++ b/tests/qemu-iotests/244.out
@@ -33,7 +33,7 @@ Convert to compressed target with data file:
 Formatting 'TEST_DIR/t.IMGFMT.src', fmt=IMGFMT size=67108864
 wrote 1048576/1048576 bytes at offset 0
 1 MiB, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
-qemu-img: error while writing sector 0: Operation not supported
+qemu-img: error while writing at byte 0: Operation not supported

 Convert uncompressed, then write compressed data manually:
 Images are identical.
-- 
2.26.0.rc2