diff mbox

[for-2.6,v3,1/3] mirror: Don't extend the last sub-chunk

Message ID 1461162766-907-2-git-send-email-kwolf@redhat.com (mailing list archive)
State New, archived
Headers show

Commit Message

Kevin Wolf April 20, 2016, 2:32 p.m. UTC 
From: Fam Zheng <famz@redhat.com>

The last sub-chunk is rounded up to the copy granularity in the target
image, resulting in a larger size than the source.

Add a function to clip the copied sectors to the end.

This undoes the "wrong" changes to tests/qemu-iotests/109.out in
e5b43573e28. The remaining two offset changes are okay.

[ kwolf: Use DIV_ROUND_UP to calculate nb_chunks now ]

Reported-by: Kevin Wolf <kwolf@redhat.com>
Signed-off-by: Fam Zheng <famz@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
---
 block/mirror.c             | 19 +++++++++++++++----
 tests/qemu-iotests/109.out | 44 ++++++++++++++++++++++----------------------
 2 files changed, 37 insertions(+), 26 deletions(-)

Comments

Max Reitz April 20, 2016, 2:46 p.m. UTC | #1 
On 20.04.2016 16:32, Kevin Wolf wrote:
> From: Fam Zheng <famz@redhat.com>
> 
> The last sub-chunk is rounded up to the copy granularity in the target
> image, resulting in a larger size than the source.
> 
> Add a function to clip the copied sectors to the end.
> 
> This undoes the "wrong" changes to tests/qemu-iotests/109.out in
> e5b43573e28. The remaining two offset changes are okay.
> 
> [ kwolf: Use DIV_ROUND_UP to calculate nb_chunks now ]
> 
> Reported-by: Kevin Wolf <kwolf@redhat.com>
> Signed-off-by: Fam Zheng <famz@redhat.com>
> Signed-off-by: Kevin Wolf <kwolf@redhat.com>
> ---
>  block/mirror.c             | 19 +++++++++++++++----
>  tests/qemu-iotests/109.out | 44 ++++++++++++++++++++++----------------------
>  2 files changed, 37 insertions(+), 26 deletions(-)

Reviewed-by: Max Reitz <mreitz@redhat.com>
Jeff Cody April 20, 2016, 2:47 p.m. UTC | #2 
On Wed, Apr 20, 2016 at 04:32:44PM +0200, Kevin Wolf wrote:
> From: Fam Zheng <famz@redhat.com>
> 
> The last sub-chunk is rounded up to the copy granularity in the target
> image, resulting in a larger size than the source.
> 
> Add a function to clip the copied sectors to the end.
> 
> This undoes the "wrong" changes to tests/qemu-iotests/109.out in
> e5b43573e28. The remaining two offset changes are okay.
> 
> [ kwolf: Use DIV_ROUND_UP to calculate nb_chunks now ]
> 
> Reported-by: Kevin Wolf <kwolf@redhat.com>
> Signed-off-by: Fam Zheng <famz@redhat.com>
> Signed-off-by: Kevin Wolf <kwolf@redhat.com>
> ---
>  block/mirror.c             | 19 +++++++++++++++----
>  tests/qemu-iotests/109.out | 44 ++++++++++++++++++++++----------------------
>  2 files changed, 37 insertions(+), 26 deletions(-)
> 
> diff --git a/block/mirror.c b/block/mirror.c
> index 9df1fae..d56e30e 100644
> --- a/block/mirror.c
> +++ b/block/mirror.c
> @@ -108,7 +108,7 @@ static void mirror_iteration_done(MirrorOp *op, int ret)
>  
>      sectors_per_chunk = s->granularity >> BDRV_SECTOR_BITS;
>      chunk_num = op->sector_num / sectors_per_chunk;
> -    nb_chunks = op->nb_sectors / sectors_per_chunk;
> +    nb_chunks = DIV_ROUND_UP(op->nb_sectors, sectors_per_chunk);
>      bitmap_clear(s->in_flight_bitmap, chunk_num, nb_chunks);
>      if (ret >= 0) {
>          if (s->cow_bitmap) {
> @@ -161,6 +161,14 @@ static void mirror_read_complete(void *opaque, int ret)
>                      mirror_write_complete, op);
>  }
>  
> +static inline void mirror_clip_sectors(MirrorBlockJob *s,
> +                                       int64_t sector_num,
> +                                       int *nb_sectors)
> +{
> +    *nb_sectors = MIN(*nb_sectors,
> +                      s->bdev_length / BDRV_SECTOR_SIZE - sector_num);
> +}
> +
>  /* Round sector_num and/or nb_sectors to target cluster if COW is needed, and
>   * return the offset of the adjusted tail sector against original. */
>  static int mirror_cow_align(MirrorBlockJob *s,
> @@ -189,6 +197,9 @@ static int mirror_cow_align(MirrorBlockJob *s,
>                                                 s->target_cluster_sectors);
>          }
>      }
> +    /* Clipping may result in align_nb_sectors unaligned to chunk boundary, but
> +     * that doesn't matter because it's already the end of source image. */
> +    mirror_clip_sectors(s, align_sector_num, &align_nb_sectors);
>  
>      ret = align_sector_num + align_nb_sectors - (*sector_num + *nb_sectors);
>      *sector_num = align_sector_num;
> @@ -231,9 +242,8 @@ static int mirror_do_read(MirrorBlockJob *s, int64_t sector_num,
>      /* The sector range must meet granularity because:
>       * 1) Caller passes in aligned values;
>       * 2) mirror_cow_align is used only when target cluster is larger. */
> -    assert(!(nb_sectors % sectors_per_chunk));
>      assert(!(sector_num % sectors_per_chunk));
> -    nb_chunks = nb_sectors / sectors_per_chunk;
> +    nb_chunks = DIV_ROUND_UP(nb_sectors, sectors_per_chunk);
>  
>      while (s->buf_free_count < nb_chunks) {
>          trace_mirror_yield_in_flight(s, sector_num, s->in_flight);
> @@ -384,6 +394,7 @@ static uint64_t coroutine_fn mirror_iteration(MirrorBlockJob *s)
>              }
>          }
>  
> +        mirror_clip_sectors(s, sector_num, &io_sectors);
>          switch (mirror_method) {
>          case MIRROR_METHOD_COPY:
>              io_sectors = mirror_do_read(s, sector_num, io_sectors);
> @@ -399,7 +410,7 @@ static uint64_t coroutine_fn mirror_iteration(MirrorBlockJob *s)
>          }
>          assert(io_sectors);
>          sector_num += io_sectors;
> -        nb_chunks -= io_sectors / sectors_per_chunk;
> +        nb_chunks -= DIV_ROUND_UP(io_sectors, sectors_per_chunk);
>          delay_ns += ratelimit_calculate_delay(&s->limit, io_sectors);
>      }
>      return delay_ns;
> diff --git a/tests/qemu-iotests/109.out b/tests/qemu-iotests/109.out
> index b3358de..38bc073 100644
> --- a/tests/qemu-iotests/109.out
> +++ b/tests/qemu-iotests/109.out
> @@ -10,14 +10,14 @@ Automatically detecting the format is dangerous for raw images, write operations
>  Specify the 'raw' format explicitly to remove the restrictions.
>  {"return": {}}
>  {"timestamp": {"seconds":  TIMESTAMP, "microseconds":  TIMESTAMP}, "event": "BLOCK_JOB_ERROR", "data": {"device": "src", "operation": "write", "action": "report"}}
> -{"timestamp": {"seconds":  TIMESTAMP, "microseconds":  TIMESTAMP}, "event": "BLOCK_JOB_COMPLETED", "data": {"device": "src", "len": 65536, "offset": 0, "speed": 0, "type": "mirror", "error": "Operation not permitted"}}
> +{"timestamp": {"seconds":  TIMESTAMP, "microseconds":  TIMESTAMP}, "event": "BLOCK_JOB_COMPLETED", "data": {"device": "src", "len": 1024, "offset": 0, "speed": 0, "type": "mirror", "error": "Operation not permitted"}}
>  {"return": []}
>  read 65536/65536 bytes at offset 0
>  64 KiB, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
>  {"return": {}}
>  {"return": {}}
> -{"timestamp": {"seconds":  TIMESTAMP, "microseconds":  TIMESTAMP}, "event": "BLOCK_JOB_READY", "data": {"device": "src", "len": 65536, "offset": 65536, "speed": 0, "type": "mirror"}}
> -{"return": [{"io-status": "ok", "device": "src", "busy": false, "len": 65536, "offset": 65536, "paused": false, "speed": 0, "ready": true, "type": "mirror"}]}
> +{"timestamp": {"seconds":  TIMESTAMP, "microseconds":  TIMESTAMP}, "event": "BLOCK_JOB_READY", "data": {"device": "src", "len": 1024, "offset": 1024, "speed": 0, "type": "mirror"}}
> +{"return": [{"io-status": "ok", "device": "src", "busy": false, "len": 1024, "offset": 1024, "paused": false, "speed": 0, "ready": true, "type": "mirror"}]}
>  Warning: Image size mismatch!
>  Images are identical.
>  
> @@ -31,14 +31,14 @@ Automatically detecting the format is dangerous for raw images, write operations
>  Specify the 'raw' format explicitly to remove the restrictions.
>  {"return": {}}
>  {"timestamp": {"seconds":  TIMESTAMP, "microseconds":  TIMESTAMP}, "event": "BLOCK_JOB_ERROR", "data": {"device": "src", "operation": "write", "action": "report"}}
> -{"timestamp": {"seconds":  TIMESTAMP, "microseconds":  TIMESTAMP}, "event": "BLOCK_JOB_COMPLETED", "data": {"device": "src", "len": 262144, "offset": 65536, "speed": 0, "type": "mirror", "error": "Operation not permitted"}}
> +{"timestamp": {"seconds":  TIMESTAMP, "microseconds":  TIMESTAMP}, "event": "BLOCK_JOB_COMPLETED", "data": {"device": "src", "len": 197120, "offset": 512, "speed": 0, "type": "mirror", "error": "Operation not permitted"}}
>  {"return": []}
>  read 65536/65536 bytes at offset 0
>  64 KiB, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
>  {"return": {}}
>  {"return": {}}
> -{"timestamp": {"seconds":  TIMESTAMP, "microseconds":  TIMESTAMP}, "event": "BLOCK_JOB_READY", "data": {"device": "src", "len": 262144, "offset": 262144, "speed": 0, "type": "mirror"}}
> -{"return": [{"io-status": "ok", "device": "src", "busy": false, "len": 262144, "offset": 262144, "paused": false, "speed": 0, "ready": true, "type": "mirror"}]}
> +{"timestamp": {"seconds":  TIMESTAMP, "microseconds":  TIMESTAMP}, "event": "BLOCK_JOB_READY", "data": {"device": "src", "len": 197120, "offset": 197120, "speed": 0, "type": "mirror"}}
> +{"return": [{"io-status": "ok", "device": "src", "busy": false, "len": 197120, "offset": 197120, "paused": false, "speed": 0, "ready": true, "type": "mirror"}]}
>  Warning: Image size mismatch!
>  Images are identical.
>  
> @@ -73,14 +73,14 @@ Automatically detecting the format is dangerous for raw images, write operations
>  Specify the 'raw' format explicitly to remove the restrictions.
>  {"return": {}}
>  {"timestamp": {"seconds":  TIMESTAMP, "microseconds":  TIMESTAMP}, "event": "BLOCK_JOB_ERROR", "data": {"device": "src", "operation": "write", "action": "report"}}
> -{"timestamp": {"seconds":  TIMESTAMP, "microseconds":  TIMESTAMP}, "event": "BLOCK_JOB_COMPLETED", "data": {"device": "src", "len": 65536, "offset": 0, "speed": 0, "type": "mirror", "error": "Operation not permitted"}}
> +{"timestamp": {"seconds":  TIMESTAMP, "microseconds":  TIMESTAMP}, "event": "BLOCK_JOB_COMPLETED", "data": {"device": "src", "len": 1024, "offset": 0, "speed": 0, "type": "mirror", "error": "Operation not permitted"}}
>  {"return": []}
>  read 65536/65536 bytes at offset 0
>  64 KiB, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
>  {"return": {}}
>  {"return": {}}
> -{"timestamp": {"seconds":  TIMESTAMP, "microseconds":  TIMESTAMP}, "event": "BLOCK_JOB_READY", "data": {"device": "src", "len": 65536, "offset": 65536, "speed": 0, "type": "mirror"}}
> -{"return": [{"io-status": "ok", "device": "src", "busy": false, "len": 65536, "offset": 65536, "paused": false, "speed": 0, "ready": true, "type": "mirror"}]}
> +{"timestamp": {"seconds":  TIMESTAMP, "microseconds":  TIMESTAMP}, "event": "BLOCK_JOB_READY", "data": {"device": "src", "len": 1024, "offset": 1024, "speed": 0, "type": "mirror"}}
> +{"return": [{"io-status": "ok", "device": "src", "busy": false, "len": 1024, "offset": 1024, "paused": false, "speed": 0, "ready": true, "type": "mirror"}]}
>  Warning: Image size mismatch!
>  Images are identical.
>  
> @@ -115,14 +115,14 @@ Automatically detecting the format is dangerous for raw images, write operations
>  Specify the 'raw' format explicitly to remove the restrictions.
>  {"return": {}}
>  {"timestamp": {"seconds":  TIMESTAMP, "microseconds":  TIMESTAMP}, "event": "BLOCK_JOB_ERROR", "data": {"device": "src", "operation": "write", "action": "report"}}
> -{"timestamp": {"seconds":  TIMESTAMP, "microseconds":  TIMESTAMP}, "event": "BLOCK_JOB_COMPLETED", "data": {"device": "src", "len": 65536, "offset": 0, "speed": 0, "type": "mirror", "error": "Operation not permitted"}}
> +{"timestamp": {"seconds":  TIMESTAMP, "microseconds":  TIMESTAMP}, "event": "BLOCK_JOB_COMPLETED", "data": {"device": "src", "len": 2560, "offset": 0, "speed": 0, "type": "mirror", "error": "Operation not permitted"}}
>  {"return": []}
>  read 65536/65536 bytes at offset 0
>  64 KiB, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
>  {"return": {}}
>  {"return": {}}
> -{"timestamp": {"seconds":  TIMESTAMP, "microseconds":  TIMESTAMP}, "event": "BLOCK_JOB_READY", "data": {"device": "src", "len": 65536, "offset": 65536, "speed": 0, "type": "mirror"}}
> -{"return": [{"io-status": "ok", "device": "src", "busy": false, "len": 65536, "offset": 65536, "paused": false, "speed": 0, "ready": true, "type": "mirror"}]}
> +{"timestamp": {"seconds":  TIMESTAMP, "microseconds":  TIMESTAMP}, "event": "BLOCK_JOB_READY", "data": {"device": "src", "len": 2560, "offset": 2560, "speed": 0, "type": "mirror"}}
> +{"return": [{"io-status": "ok", "device": "src", "busy": false, "len": 2560, "offset": 2560, "paused": false, "speed": 0, "ready": true, "type": "mirror"}]}
>  Warning: Image size mismatch!
>  Images are identical.
>  
> @@ -135,14 +135,14 @@ Automatically detecting the format is dangerous for raw images, write operations
>  Specify the 'raw' format explicitly to remove the restrictions.
>  {"return": {}}
>  {"timestamp": {"seconds":  TIMESTAMP, "microseconds":  TIMESTAMP}, "event": "BLOCK_JOB_ERROR", "data": {"device": "src", "operation": "write", "action": "report"}}
> -{"timestamp": {"seconds":  TIMESTAMP, "microseconds":  TIMESTAMP}, "event": "BLOCK_JOB_COMPLETED", "data": {"device": "src", "len": 65536, "offset": 0, "speed": 0, "type": "mirror", "error": "Operation not permitted"}}
> +{"timestamp": {"seconds":  TIMESTAMP, "microseconds":  TIMESTAMP}, "event": "BLOCK_JOB_COMPLETED", "data": {"device": "src", "len": 2560, "offset": 0, "speed": 0, "type": "mirror", "error": "Operation not permitted"}}
>  {"return": []}
>  read 65536/65536 bytes at offset 0
>  64 KiB, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
>  {"return": {}}
>  {"return": {}}
> -{"timestamp": {"seconds":  TIMESTAMP, "microseconds":  TIMESTAMP}, "event": "BLOCK_JOB_READY", "data": {"device": "src", "len": 65536, "offset": 65536, "speed": 0, "type": "mirror"}}
> -{"return": [{"io-status": "ok", "device": "src", "busy": false, "len": 65536, "offset": 65536, "paused": false, "speed": 0, "ready": true, "type": "mirror"}]}
> +{"timestamp": {"seconds":  TIMESTAMP, "microseconds":  TIMESTAMP}, "event": "BLOCK_JOB_READY", "data": {"device": "src", "len": 2560, "offset": 2560, "speed": 0, "type": "mirror"}}
> +{"return": [{"io-status": "ok", "device": "src", "busy": false, "len": 2560, "offset": 2560, "paused": false, "speed": 0, "ready": true, "type": "mirror"}]}
>  Image resized.
>  Warning: Image size mismatch!
>  Images are identical.
> @@ -198,14 +198,14 @@ Automatically detecting the format is dangerous for raw images, write operations
>  Specify the 'raw' format explicitly to remove the restrictions.
>  {"return": {}}
>  {"timestamp": {"seconds":  TIMESTAMP, "microseconds":  TIMESTAMP}, "event": "BLOCK_JOB_ERROR", "data": {"device": "src", "operation": "write", "action": "report"}}
> -{"timestamp": {"seconds":  TIMESTAMP, "microseconds":  TIMESTAMP}, "event": "BLOCK_JOB_COMPLETED", "data": {"device": "src", "len": 65536, "offset": 0, "speed": 0, "type": "mirror", "error": "Operation not permitted"}}
> +{"timestamp": {"seconds":  TIMESTAMP, "microseconds":  TIMESTAMP}, "event": "BLOCK_JOB_COMPLETED", "data": {"device": "src", "len": 2048, "offset": 0, "speed": 0, "type": "mirror", "error": "Operation not permitted"}}
>  {"return": []}
>  read 65536/65536 bytes at offset 0
>  64 KiB, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
>  {"return": {}}
>  {"return": {}}
> -{"timestamp": {"seconds":  TIMESTAMP, "microseconds":  TIMESTAMP}, "event": "BLOCK_JOB_READY", "data": {"device": "src", "len": 65536, "offset": 65536, "speed": 0, "type": "mirror"}}
> -{"return": [{"io-status": "ok", "device": "src", "busy": false, "len": 65536, "offset": 65536, "paused": false, "speed": 0, "ready": true, "type": "mirror"}]}
> +{"timestamp": {"seconds":  TIMESTAMP, "microseconds":  TIMESTAMP}, "event": "BLOCK_JOB_READY", "data": {"device": "src", "len": 2048, "offset": 2048, "speed": 0, "type": "mirror"}}
> +{"return": [{"io-status": "ok", "device": "src", "busy": false, "len": 2048, "offset": 2048, "paused": false, "speed": 0, "ready": true, "type": "mirror"}]}
>  Image resized.
>  Warning: Image size mismatch!
>  Images are identical.
> @@ -218,14 +218,14 @@ WARNING: Image format was not specified for 'TEST_DIR/t.raw' and probing guessed
>  Automatically detecting the format is dangerous for raw images, write operations on block 0 will be restricted.
>  Specify the 'raw' format explicitly to remove the restrictions.
>  {"return": {}}
> -{"timestamp": {"seconds":  TIMESTAMP, "microseconds":  TIMESTAMP}, "event": "BLOCK_JOB_READY", "data": {"device": "src", "len": 65536, "offset": 65536, "speed": 0, "type": "mirror"}}
> -{"return": [{"io-status": "ok", "device": "src", "busy": false, "len": 65536, "offset": 65536, "paused": false, "speed": 0, "ready": true, "type": "mirror"}]}
> +{"timestamp": {"seconds":  TIMESTAMP, "microseconds":  TIMESTAMP}, "event": "BLOCK_JOB_READY", "data": {"device": "src", "len": 512, "offset": 512, "speed": 0, "type": "mirror"}}
> +{"return": [{"io-status": "ok", "device": "src", "busy": false, "len": 512, "offset": 512, "paused": false, "speed": 0, "ready": true, "type": "mirror"}]}
>  Warning: Image size mismatch!
>  Images are identical.
>  {"return": {}}
>  {"return": {}}
> -{"timestamp": {"seconds":  TIMESTAMP, "microseconds":  TIMESTAMP}, "event": "BLOCK_JOB_READY", "data": {"device": "src", "len": 65536, "offset": 65536, "speed": 0, "type": "mirror"}}
> -{"return": [{"io-status": "ok", "device": "src", "busy": false, "len": 65536, "offset": 65536, "paused": false, "speed": 0, "ready": true, "type": "mirror"}]}
> +{"timestamp": {"seconds":  TIMESTAMP, "microseconds":  TIMESTAMP}, "event": "BLOCK_JOB_READY", "data": {"device": "src", "len": 512, "offset": 512, "speed": 0, "type": "mirror"}}
> +{"return": [{"io-status": "ok", "device": "src", "busy": false, "len": 512, "offset": 512, "paused": false, "speed": 0, "ready": true, "type": "mirror"}]}
>  Warning: Image size mismatch!
>  Images are identical.
>  *** done
> -- 
> 1.8.3.1
>

Reviewed-by: Jeff Cody <jcody@redhat.com>
diff mbox

Patch

diff --git a/block/mirror.c b/block/mirror.c
index 9df1fae..d56e30e 100644
--- a/block/mirror.c
+++ b/block/mirror.c
@@ -108,7 +108,7 @@  static void mirror_iteration_done(MirrorOp *op, int ret)
 
     sectors_per_chunk = s->granularity >> BDRV_SECTOR_BITS;
     chunk_num = op->sector_num / sectors_per_chunk;
-    nb_chunks = op->nb_sectors / sectors_per_chunk;
+    nb_chunks = DIV_ROUND_UP(op->nb_sectors, sectors_per_chunk);
     bitmap_clear(s->in_flight_bitmap, chunk_num, nb_chunks);
     if (ret >= 0) {
         if (s->cow_bitmap) {
@@ -161,6 +161,14 @@  static void mirror_read_complete(void *opaque, int ret)
                     mirror_write_complete, op);
 }
 
+static inline void mirror_clip_sectors(MirrorBlockJob *s,
+                                       int64_t sector_num,
+                                       int *nb_sectors)
+{
+    *nb_sectors = MIN(*nb_sectors,
+                      s->bdev_length / BDRV_SECTOR_SIZE - sector_num);
+}
+
 /* Round sector_num and/or nb_sectors to target cluster if COW is needed, and
  * return the offset of the adjusted tail sector against original. */
 static int mirror_cow_align(MirrorBlockJob *s,
@@ -189,6 +197,9 @@  static int mirror_cow_align(MirrorBlockJob *s,
                                                s->target_cluster_sectors);
         }
     }
+    /* Clipping may result in align_nb_sectors unaligned to chunk boundary, but
+     * that doesn't matter because it's already the end of source image. */
+    mirror_clip_sectors(s, align_sector_num, &align_nb_sectors);
 
     ret = align_sector_num + align_nb_sectors - (*sector_num + *nb_sectors);
     *sector_num = align_sector_num;
@@ -231,9 +242,8 @@  static int mirror_do_read(MirrorBlockJob *s, int64_t sector_num,
     /* The sector range must meet granularity because:
      * 1) Caller passes in aligned values;
      * 2) mirror_cow_align is used only when target cluster is larger. */
-    assert(!(nb_sectors % sectors_per_chunk));
     assert(!(sector_num % sectors_per_chunk));
-    nb_chunks = nb_sectors / sectors_per_chunk;
+    nb_chunks = DIV_ROUND_UP(nb_sectors, sectors_per_chunk);
 
     while (s->buf_free_count < nb_chunks) {
         trace_mirror_yield_in_flight(s, sector_num, s->in_flight);
@@ -384,6 +394,7 @@  static uint64_t coroutine_fn mirror_iteration(MirrorBlockJob *s)
             }
         }
 
+        mirror_clip_sectors(s, sector_num, &io_sectors);
         switch (mirror_method) {
         case MIRROR_METHOD_COPY:
             io_sectors = mirror_do_read(s, sector_num, io_sectors);
@@ -399,7 +410,7 @@  static uint64_t coroutine_fn mirror_iteration(MirrorBlockJob *s)
         }
         assert(io_sectors);
         sector_num += io_sectors;
-        nb_chunks -= io_sectors / sectors_per_chunk;
+        nb_chunks -= DIV_ROUND_UP(io_sectors, sectors_per_chunk);
         delay_ns += ratelimit_calculate_delay(&s->limit, io_sectors);
     }
     return delay_ns;
diff --git a/tests/qemu-iotests/109.out b/tests/qemu-iotests/109.out
index b3358de..38bc073 100644
--- a/tests/qemu-iotests/109.out
+++ b/tests/qemu-iotests/109.out
@@ -10,14 +10,14 @@  Automatically detecting the format is dangerous for raw images, write operations
 Specify the 'raw' format explicitly to remove the restrictions.
 {"return": {}}
 {"timestamp": {"seconds":  TIMESTAMP, "microseconds":  TIMESTAMP}, "event": "BLOCK_JOB_ERROR", "data": {"device": "src", "operation": "write", "action": "report"}}
-{"timestamp": {"seconds":  TIMESTAMP, "microseconds":  TIMESTAMP}, "event": "BLOCK_JOB_COMPLETED", "data": {"device": "src", "len": 65536, "offset": 0, "speed": 0, "type": "mirror", "error": "Operation not permitted"}}
+{"timestamp": {"seconds":  TIMESTAMP, "microseconds":  TIMESTAMP}, "event": "BLOCK_JOB_COMPLETED", "data": {"device": "src", "len": 1024, "offset": 0, "speed": 0, "type": "mirror", "error": "Operation not permitted"}}
 {"return": []}
 read 65536/65536 bytes at offset 0
 64 KiB, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
 {"return": {}}
 {"return": {}}
-{"timestamp": {"seconds":  TIMESTAMP, "microseconds":  TIMESTAMP}, "event": "BLOCK_JOB_READY", "data": {"device": "src", "len": 65536, "offset": 65536, "speed": 0, "type": "mirror"}}
-{"return": [{"io-status": "ok", "device": "src", "busy": false, "len": 65536, "offset": 65536, "paused": false, "speed": 0, "ready": true, "type": "mirror"}]}
+{"timestamp": {"seconds":  TIMESTAMP, "microseconds":  TIMESTAMP}, "event": "BLOCK_JOB_READY", "data": {"device": "src", "len": 1024, "offset": 1024, "speed": 0, "type": "mirror"}}
+{"return": [{"io-status": "ok", "device": "src", "busy": false, "len": 1024, "offset": 1024, "paused": false, "speed": 0, "ready": true, "type": "mirror"}]}
 Warning: Image size mismatch!
 Images are identical.
 
@@ -31,14 +31,14 @@  Automatically detecting the format is dangerous for raw images, write operations
 Specify the 'raw' format explicitly to remove the restrictions.
 {"return": {}}
 {"timestamp": {"seconds":  TIMESTAMP, "microseconds":  TIMESTAMP}, "event": "BLOCK_JOB_ERROR", "data": {"device": "src", "operation": "write", "action": "report"}}
-{"timestamp": {"seconds":  TIMESTAMP, "microseconds":  TIMESTAMP}, "event": "BLOCK_JOB_COMPLETED", "data": {"device": "src", "len": 262144, "offset": 65536, "speed": 0, "type": "mirror", "error": "Operation not permitted"}}
+{"timestamp": {"seconds":  TIMESTAMP, "microseconds":  TIMESTAMP}, "event": "BLOCK_JOB_COMPLETED", "data": {"device": "src", "len": 197120, "offset": 512, "speed": 0, "type": "mirror", "error": "Operation not permitted"}}
 {"return": []}
 read 65536/65536 bytes at offset 0
 64 KiB, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
 {"return": {}}
 {"return": {}}
-{"timestamp": {"seconds":  TIMESTAMP, "microseconds":  TIMESTAMP}, "event": "BLOCK_JOB_READY", "data": {"device": "src", "len": 262144, "offset": 262144, "speed": 0, "type": "mirror"}}
-{"return": [{"io-status": "ok", "device": "src", "busy": false, "len": 262144, "offset": 262144, "paused": false, "speed": 0, "ready": true, "type": "mirror"}]}
+{"timestamp": {"seconds":  TIMESTAMP, "microseconds":  TIMESTAMP}, "event": "BLOCK_JOB_READY", "data": {"device": "src", "len": 197120, "offset": 197120, "speed": 0, "type": "mirror"}}
+{"return": [{"io-status": "ok", "device": "src", "busy": false, "len": 197120, "offset": 197120, "paused": false, "speed": 0, "ready": true, "type": "mirror"}]}
 Warning: Image size mismatch!
 Images are identical.
 
@@ -73,14 +73,14 @@  Automatically detecting the format is dangerous for raw images, write operations
 Specify the 'raw' format explicitly to remove the restrictions.
 {"return": {}}
 {"timestamp": {"seconds":  TIMESTAMP, "microseconds":  TIMESTAMP}, "event": "BLOCK_JOB_ERROR", "data": {"device": "src", "operation": "write", "action": "report"}}
-{"timestamp": {"seconds":  TIMESTAMP, "microseconds":  TIMESTAMP}, "event": "BLOCK_JOB_COMPLETED", "data": {"device": "src", "len": 65536, "offset": 0, "speed": 0, "type": "mirror", "error": "Operation not permitted"}}
+{"timestamp": {"seconds":  TIMESTAMP, "microseconds":  TIMESTAMP}, "event": "BLOCK_JOB_COMPLETED", "data": {"device": "src", "len": 1024, "offset": 0, "speed": 0, "type": "mirror", "error": "Operation not permitted"}}
 {"return": []}
 read 65536/65536 bytes at offset 0
 64 KiB, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
 {"return": {}}
 {"return": {}}
-{"timestamp": {"seconds":  TIMESTAMP, "microseconds":  TIMESTAMP}, "event": "BLOCK_JOB_READY", "data": {"device": "src", "len": 65536, "offset": 65536, "speed": 0, "type": "mirror"}}
-{"return": [{"io-status": "ok", "device": "src", "busy": false, "len": 65536, "offset": 65536, "paused": false, "speed": 0, "ready": true, "type": "mirror"}]}
+{"timestamp": {"seconds":  TIMESTAMP, "microseconds":  TIMESTAMP}, "event": "BLOCK_JOB_READY", "data": {"device": "src", "len": 1024, "offset": 1024, "speed": 0, "type": "mirror"}}
+{"return": [{"io-status": "ok", "device": "src", "busy": false, "len": 1024, "offset": 1024, "paused": false, "speed": 0, "ready": true, "type": "mirror"}]}
 Warning: Image size mismatch!
 Images are identical.
 
@@ -115,14 +115,14 @@  Automatically detecting the format is dangerous for raw images, write operations
 Specify the 'raw' format explicitly to remove the restrictions.
 {"return": {}}
 {"timestamp": {"seconds":  TIMESTAMP, "microseconds":  TIMESTAMP}, "event": "BLOCK_JOB_ERROR", "data": {"device": "src", "operation": "write", "action": "report"}}
-{"timestamp": {"seconds":  TIMESTAMP, "microseconds":  TIMESTAMP}, "event": "BLOCK_JOB_COMPLETED", "data": {"device": "src", "len": 65536, "offset": 0, "speed": 0, "type": "mirror", "error": "Operation not permitted"}}
+{"timestamp": {"seconds":  TIMESTAMP, "microseconds":  TIMESTAMP}, "event": "BLOCK_JOB_COMPLETED", "data": {"device": "src", "len": 2560, "offset": 0, "speed": 0, "type": "mirror", "error": "Operation not permitted"}}
 {"return": []}
 read 65536/65536 bytes at offset 0
 64 KiB, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
 {"return": {}}
 {"return": {}}
-{"timestamp": {"seconds":  TIMESTAMP, "microseconds":  TIMESTAMP}, "event": "BLOCK_JOB_READY", "data": {"device": "src", "len": 65536, "offset": 65536, "speed": 0, "type": "mirror"}}
-{"return": [{"io-status": "ok", "device": "src", "busy": false, "len": 65536, "offset": 65536, "paused": false, "speed": 0, "ready": true, "type": "mirror"}]}
+{"timestamp": {"seconds":  TIMESTAMP, "microseconds":  TIMESTAMP}, "event": "BLOCK_JOB_READY", "data": {"device": "src", "len": 2560, "offset": 2560, "speed": 0, "type": "mirror"}}
+{"return": [{"io-status": "ok", "device": "src", "busy": false, "len": 2560, "offset": 2560, "paused": false, "speed": 0, "ready": true, "type": "mirror"}]}
 Warning: Image size mismatch!
 Images are identical.
 
@@ -135,14 +135,14 @@  Automatically detecting the format is dangerous for raw images, write operations
 Specify the 'raw' format explicitly to remove the restrictions.
 {"return": {}}
 {"timestamp": {"seconds":  TIMESTAMP, "microseconds":  TIMESTAMP}, "event": "BLOCK_JOB_ERROR", "data": {"device": "src", "operation": "write", "action": "report"}}
-{"timestamp": {"seconds":  TIMESTAMP, "microseconds":  TIMESTAMP}, "event": "BLOCK_JOB_COMPLETED", "data": {"device": "src", "len": 65536, "offset": 0, "speed": 0, "type": "mirror", "error": "Operation not permitted"}}
+{"timestamp": {"seconds":  TIMESTAMP, "microseconds":  TIMESTAMP}, "event": "BLOCK_JOB_COMPLETED", "data": {"device": "src", "len": 2560, "offset": 0, "speed": 0, "type": "mirror", "error": "Operation not permitted"}}
 {"return": []}
 read 65536/65536 bytes at offset 0
 64 KiB, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
 {"return": {}}
 {"return": {}}
-{"timestamp": {"seconds":  TIMESTAMP, "microseconds":  TIMESTAMP}, "event": "BLOCK_JOB_READY", "data": {"device": "src", "len": 65536, "offset": 65536, "speed": 0, "type": "mirror"}}
-{"return": [{"io-status": "ok", "device": "src", "busy": false, "len": 65536, "offset": 65536, "paused": false, "speed": 0, "ready": true, "type": "mirror"}]}
+{"timestamp": {"seconds":  TIMESTAMP, "microseconds":  TIMESTAMP}, "event": "BLOCK_JOB_READY", "data": {"device": "src", "len": 2560, "offset": 2560, "speed": 0, "type": "mirror"}}
+{"return": [{"io-status": "ok", "device": "src", "busy": false, "len": 2560, "offset": 2560, "paused": false, "speed": 0, "ready": true, "type": "mirror"}]}
 Image resized.
 Warning: Image size mismatch!
 Images are identical.
@@ -198,14 +198,14 @@  Automatically detecting the format is dangerous for raw images, write operations
 Specify the 'raw' format explicitly to remove the restrictions.
 {"return": {}}
 {"timestamp": {"seconds":  TIMESTAMP, "microseconds":  TIMESTAMP}, "event": "BLOCK_JOB_ERROR", "data": {"device": "src", "operation": "write", "action": "report"}}
-{"timestamp": {"seconds":  TIMESTAMP, "microseconds":  TIMESTAMP}, "event": "BLOCK_JOB_COMPLETED", "data": {"device": "src", "len": 65536, "offset": 0, "speed": 0, "type": "mirror", "error": "Operation not permitted"}}
+{"timestamp": {"seconds":  TIMESTAMP, "microseconds":  TIMESTAMP}, "event": "BLOCK_JOB_COMPLETED", "data": {"device": "src", "len": 2048, "offset": 0, "speed": 0, "type": "mirror", "error": "Operation not permitted"}}
 {"return": []}
 read 65536/65536 bytes at offset 0
 64 KiB, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
 {"return": {}}
 {"return": {}}
-{"timestamp": {"seconds":  TIMESTAMP, "microseconds":  TIMESTAMP}, "event": "BLOCK_JOB_READY", "data": {"device": "src", "len": 65536, "offset": 65536, "speed": 0, "type": "mirror"}}
-{"return": [{"io-status": "ok", "device": "src", "busy": false, "len": 65536, "offset": 65536, "paused": false, "speed": 0, "ready": true, "type": "mirror"}]}
+{"timestamp": {"seconds":  TIMESTAMP, "microseconds":  TIMESTAMP}, "event": "BLOCK_JOB_READY", "data": {"device": "src", "len": 2048, "offset": 2048, "speed": 0, "type": "mirror"}}
+{"return": [{"io-status": "ok", "device": "src", "busy": false, "len": 2048, "offset": 2048, "paused": false, "speed": 0, "ready": true, "type": "mirror"}]}
 Image resized.
 Warning: Image size mismatch!
 Images are identical.
@@ -218,14 +218,14 @@  WARNING: Image format was not specified for 'TEST_DIR/t.raw' and probing guessed
 Automatically detecting the format is dangerous for raw images, write operations on block 0 will be restricted.
 Specify the 'raw' format explicitly to remove the restrictions.
 {"return": {}}
-{"timestamp": {"seconds":  TIMESTAMP, "microseconds":  TIMESTAMP}, "event": "BLOCK_JOB_READY", "data": {"device": "src", "len": 65536, "offset": 65536, "speed": 0, "type": "mirror"}}
-{"return": [{"io-status": "ok", "device": "src", "busy": false, "len": 65536, "offset": 65536, "paused": false, "speed": 0, "ready": true, "type": "mirror"}]}
+{"timestamp": {"seconds":  TIMESTAMP, "microseconds":  TIMESTAMP}, "event": "BLOCK_JOB_READY", "data": {"device": "src", "len": 512, "offset": 512, "speed": 0, "type": "mirror"}}
+{"return": [{"io-status": "ok", "device": "src", "busy": false, "len": 512, "offset": 512, "paused": false, "speed": 0, "ready": true, "type": "mirror"}]}
 Warning: Image size mismatch!
 Images are identical.
 {"return": {}}
 {"return": {}}
-{"timestamp": {"seconds":  TIMESTAMP, "microseconds":  TIMESTAMP}, "event": "BLOCK_JOB_READY", "data": {"device": "src", "len": 65536, "offset": 65536, "speed": 0, "type": "mirror"}}
-{"return": [{"io-status": "ok", "device": "src", "busy": false, "len": 65536, "offset": 65536, "paused": false, "speed": 0, "ready": true, "type": "mirror"}]}
+{"timestamp": {"seconds":  TIMESTAMP, "microseconds":  TIMESTAMP}, "event": "BLOCK_JOB_READY", "data": {"device": "src", "len": 512, "offset": 512, "speed": 0, "type": "mirror"}}
+{"return": [{"io-status": "ok", "device": "src", "busy": false, "len": 512, "offset": 512, "paused": false, "speed": 0, "ready": true, "type": "mirror"}]}
 Warning: Image size mismatch!
 Images are identical.
 *** done