Merge remote-tracking branch 'remotes/kevin/tags/for-upstream' into staging

Block layer patches

# gpg: Signature made Thu 26 Oct 2017 14:02:54 BST
# gpg:                using RSA key 0x7F09B272C88F2FD6
# gpg: Good signature from "Kevin Wolf <kwolf@redhat.com>"
# Primary key fingerprint: DC3D EB15 9A9A F95D 3D74  56FE 7F09 B272 C88F 2FD6

* remotes/kevin/tags/for-upstream: (35 commits)
  iotests: Add cluster_size=64k to 125
  qcow2: Always execute preallocate() in a coroutine
  qcow2: Fix unaligned preallocated truncation
  qcow2: Emit errp when truncating the image tail
  iotests: Filter actual image size in 184 and 191
  iotests: Pull _filter_actual_image_size from 67/87
  iotests: Add test for dataplane mirroring
  qcow2: Use BDRV_SECTOR_BITS instead of its literal value
  qemu-img.1: Image invalidation on qemu-img commit
  qemu-io: Relax 'alloc' now that block-status doesn't assert
  qcow2: Reduce is_zero() rounding
  block: Reduce bdrv_aligned_preadv() rounding
  block: Align block status requests
  qemu-img: Change img_compare() to be byte-based
  qemu-img: Change img_rebase() to be byte-based
  qemu-img: Change compare_sectors() to be byte-based
  qemu-img: Change check_empty_sectors() to byte-based
  qemu-img: Drop redundant error message in compare
  qemu-img: Add find_nonzero()
  qemu-img: Speed up compare on pre-allocated larger file
  ...

Signed-off-by: Peter Maydell <peter.maydell@linaro.org>

27 files changed, 1102 insertions, 543 deletions

diff --git a/block.c b/block.c
index 46eb1728da..684cb018da 100644
--- a/block.c
+++ b/block.c
@@ -2245,7 +2245,8 @@ int bdrv_open_backing_file(BlockDriverState *bs, QDict *parent_options,
         goto free_exit;
     }
 
-    if (bs->backing_format[0] != '\0' && !qdict_haskey(options, "driver")) {
+    if (!reference &&
+        bs->backing_format[0] != '\0' && !qdict_haskey(options, "driver")) {
         qdict_put_str(options, "driver", bs->backing_format);
     }
 
diff --git a/block/blkdebug.c b/block/blkdebug.c
index dfdf9b91aa..e21669979d 100644
--- a/block/blkdebug.c
+++ b/block/blkdebug.c
@@ -627,6 +627,17 @@ static int coroutine_fn blkdebug_co_pdiscard(BlockDriverState *bs,
     return bdrv_co_pdiscard(bs->file->bs, offset, bytes);
 }
 
+static int64_t coroutine_fn blkdebug_co_get_block_status(
+    BlockDriverState *bs, int64_t sector_num, int nb_sectors, int *pnum,
+    BlockDriverState **file)
+{
+    assert(QEMU_IS_ALIGNED(sector_num | nb_sectors,
+                           DIV_ROUND_UP(bs->bl.request_alignment,
+                                        BDRV_SECTOR_SIZE)));
+    return bdrv_co_get_block_status_from_file(bs, sector_num, nb_sectors,
+                                              pnum, file);
+}
+
 static void blkdebug_close(BlockDriverState *bs)
 {
     BDRVBlkdebugState *s = bs->opaque;
@@ -896,7 +907,7 @@ static BlockDriver bdrv_blkdebug = {
     .bdrv_co_flush_to_disk  = blkdebug_co_flush,
     .bdrv_co_pwrite_zeroes  = blkdebug_co_pwrite_zeroes,
     .bdrv_co_pdiscard       = blkdebug_co_pdiscard,
-    .bdrv_co_get_block_status = bdrv_co_get_block_status_from_file,
+    .bdrv_co_get_block_status = blkdebug_co_get_block_status,
 
     .bdrv_debug_event           = blkdebug_debug_event,
     .bdrv_debug_breakpoint      = blkdebug_debug_breakpoint,
diff --git a/block/io.c b/block/io.c
index 0854e0fdac..3d5ef2cabe 100644
--- a/block/io.c
+++ b/block/io.c
@@ -469,9 +469,9 @@ static void mark_request_serialising(BdrvTrackedRequest *req, uint64_t align)
  * Round a region to cluster boundaries
  */
 void bdrv_round_to_clusters(BlockDriverState *bs,
-                            int64_t offset, unsigned int bytes,
+                            int64_t offset, int64_t bytes,
                             int64_t *cluster_offset,
-                            unsigned int *cluster_bytes)
+                            int64_t *cluster_bytes)
 {
     BlockDriverInfo bdi;
 
@@ -716,39 +716,37 @@ int bdrv_pwrite_zeroes(BdrvChild *child, int64_t offset,
  */
 int bdrv_make_zero(BdrvChild *child, BdrvRequestFlags flags)
 {
-    int64_t target_sectors, ret, nb_sectors, sector_num = 0;
+    int ret;
+    int64_t target_size, bytes, offset = 0;
     BlockDriverState *bs = child->bs;
-    BlockDriverState *file;
-    int n;
 
-    target_sectors = bdrv_nb_sectors(bs);
-    if (target_sectors < 0) {
-        return target_sectors;
+    target_size = bdrv_getlength(bs);
+    if (target_size < 0) {
+        return target_size;
     }
 
     for (;;) {
-        nb_sectors = MIN(target_sectors - sector_num, BDRV_REQUEST_MAX_SECTORS);
-        if (nb_sectors <= 0) {
+        bytes = MIN(target_size - offset, BDRV_REQUEST_MAX_BYTES);
+        if (bytes <= 0) {
             return 0;
         }
-        ret = bdrv_get_block_status(bs, sector_num, nb_sectors, &n, &file);
+        ret = bdrv_block_status(bs, offset, bytes, &bytes, NULL, NULL);
         if (ret < 0) {
-            error_report("error getting block status at sector %" PRId64 ": %s",
-                         sector_num, strerror(-ret));
+            error_report("error getting block status at offset %" PRId64 ": %s",
+                         offset, strerror(-ret));
             return ret;
         }
         if (ret & BDRV_BLOCK_ZERO) {
-            sector_num += n;
+            offset += bytes;
             continue;
         }
-        ret = bdrv_pwrite_zeroes(child, sector_num << BDRV_SECTOR_BITS,
-                                 n << BDRV_SECTOR_BITS, flags);
+        ret = bdrv_pwrite_zeroes(child, offset, bytes, flags);
         if (ret < 0) {
-            error_report("error writing zeroes at sector %" PRId64 ": %s",
-                         sector_num, strerror(-ret));
+            error_report("error writing zeroes at offset %" PRId64 ": %s",
+                         offset, strerror(-ret));
             return ret;
         }
-        sector_num += n;
+        offset += bytes;
     }
 }
 
@@ -970,7 +968,7 @@ static int coroutine_fn bdrv_co_do_copy_on_readv(BdrvChild *child,
     struct iovec iov;
     QEMUIOVector local_qiov;
     int64_t cluster_offset;
-    unsigned int cluster_bytes;
+    int64_t cluster_bytes;
     size_t skip_bytes;
     int ret;
     int max_transfer = MIN_NON_ZERO(bs->bl.max_transfer,
@@ -1126,18 +1124,14 @@ static int coroutine_fn bdrv_aligned_preadv(BdrvChild *child,
     }
 
     if (flags & BDRV_REQ_COPY_ON_READ) {
-        /* TODO: Simplify further once bdrv_is_allocated no longer
-         * requires sector alignment */
-        int64_t start = QEMU_ALIGN_DOWN(offset, BDRV_SECTOR_SIZE);
-        int64_t end = QEMU_ALIGN_UP(offset + bytes, BDRV_SECTOR_SIZE);
         int64_t pnum;
 
-        ret = bdrv_is_allocated(bs, start, end - start, &pnum);
+        ret = bdrv_is_allocated(bs, offset, bytes, &pnum);
         if (ret < 0) {
             goto out;
         }
 
-        if (!ret || pnum != end - start) {
+        if (!ret || pnum != bytes) {
             ret = bdrv_co_do_copy_on_readv(child, offset, bytes, qiov);
             goto out;
         }
@@ -1767,16 +1761,18 @@ int bdrv_flush_all(void)
 }
 
 
-typedef struct BdrvCoGetBlockStatusData {
+typedef struct BdrvCoBlockStatusData {
     BlockDriverState *bs;
     BlockDriverState *base;
+    bool want_zero;
+    int64_t offset;
+    int64_t bytes;
+    int64_t *pnum;
+    int64_t *map;
     BlockDriverState **file;
-    int64_t sector_num;
-    int nb_sectors;
-    int *pnum;
-    int64_t ret;
+    int ret;
     bool done;
-} BdrvCoGetBlockStatusData;
+} BdrvCoBlockStatusData;
 
 int64_t coroutine_fn bdrv_co_get_block_status_from_file(BlockDriverState *bs,
                                                         int64_t sector_num,
@@ -1809,99 +1805,157 @@ int64_t coroutine_fn bdrv_co_get_block_status_from_backing(BlockDriverState *bs,
  * Drivers not implementing the functionality are assumed to not support
  * backing files, hence all their sectors are reported as allocated.
  *
- * If 'sector_num' is beyond the end of the disk image the return value is
- * BDRV_BLOCK_EOF and 'pnum' is set to 0.
+ * If 'want_zero' is true, the caller is querying for mapping purposes,
+ * and the result should include BDRV_BLOCK_OFFSET_VALID and
+ * BDRV_BLOCK_ZERO where possible; otherwise, the result may omit those
+ * bits particularly if it allows for a larger value in 'pnum'.
  *
- * 'pnum' is set to the number of sectors (including and immediately following
- * the specified sector) that are known to be in the same
- * allocated/unallocated state.
+ * If 'offset' is beyond the end of the disk image the return value is
+ * BDRV_BLOCK_EOF and 'pnum' is set to 0.
  *
- * 'nb_sectors' is the max value 'pnum' should be set to.  If nb_sectors goes
+ * 'bytes' is the max value 'pnum' should be set to.  If bytes goes
  * beyond the end of the disk image it will be clamped; if 'pnum' is set to
  * the end of the image, then the returned value will include BDRV_BLOCK_EOF.
  *
- * If returned value is positive and BDRV_BLOCK_OFFSET_VALID bit is set, 'file'
- * points to the BDS which the sector range is allocated in.
+ * 'pnum' is set to the number of bytes (including and immediately
+ * following the specified offset) that are easily known to be in the
+ * same allocated/unallocated state.  Note that a second call starting
+ * at the original offset plus returned pnum may have the same status.
+ * The returned value is non-zero on success except at end-of-file.
+ *
+ * Returns negative errno on failure.  Otherwise, if the
+ * BDRV_BLOCK_OFFSET_VALID bit is set, 'map' and 'file' (if non-NULL) are
+ * set to the host mapping and BDS corresponding to the guest offset.
  */
-static int64_t coroutine_fn bdrv_co_get_block_status(BlockDriverState *bs,
-                                                     int64_t sector_num,
-                                                     int nb_sectors, int *pnum,
-                                                     BlockDriverState **file)
-{
-    int64_t total_sectors;
-    int64_t n;
-    int64_t ret, ret2;
+static int coroutine_fn bdrv_co_block_status(BlockDriverState *bs,
+                                             bool want_zero,
+                                             int64_t offset, int64_t bytes,
+                                             int64_t *pnum, int64_t *map,
+                                             BlockDriverState **file)
+{
+    int64_t total_size;
+    int64_t n; /* bytes */
+    int ret;
+    int64_t local_map = 0;
+    BlockDriverState *local_file = NULL;
+    int64_t aligned_offset, aligned_bytes;
+    uint32_t align;
 
-    *file = NULL;
-    total_sectors = bdrv_nb_sectors(bs);
-    if (total_sectors < 0) {
-        return total_sectors;
+    assert(pnum);
+    *pnum = 0;
+    total_size = bdrv_getlength(bs);
+    if (total_size < 0) {
+        ret = total_size;
+        goto early_out;
     }
 
-    if (sector_num >= total_sectors) {
-        *pnum = 0;
-        return BDRV_BLOCK_EOF;
+    if (offset >= total_size) {
+        ret = BDRV_BLOCK_EOF;
+        goto early_out;
     }
-    if (!nb_sectors) {
-        *pnum = 0;
-        return 0;
+    if (!bytes) {
+        ret = 0;
+        goto early_out;
     }
 
-    n = total_sectors - sector_num;
-    if (n < nb_sectors) {
-        nb_sectors = n;
+    n = total_size - offset;
+    if (n < bytes) {
+        bytes = n;
     }
 
     if (!bs->drv->bdrv_co_get_block_status) {
-        *pnum = nb_sectors;
+        *pnum = bytes;
         ret = BDRV_BLOCK_DATA | BDRV_BLOCK_ALLOCATED;
-        if (sector_num + nb_sectors == total_sectors) {
+        if (offset + bytes == total_size) {
             ret |= BDRV_BLOCK_EOF;
         }
         if (bs->drv->protocol_name) {
-            ret |= BDRV_BLOCK_OFFSET_VALID | (sector_num * BDRV_SECTOR_SIZE);
-            *file = bs;
+            ret |= BDRV_BLOCK_OFFSET_VALID;
+            local_map = offset;
+            local_file = bs;
         }
-        return ret;
+        goto early_out;
     }
 
     bdrv_inc_in_flight(bs);
-    ret = bs->drv->bdrv_co_get_block_status(bs, sector_num, nb_sectors, pnum,
-                                            file);
-    if (ret < 0) {
-        *pnum = 0;
-        goto out;
+
+    /* Round out to request_alignment boundaries */
+    /* TODO: until we have a byte-based driver callback, we also have to
+     * round out to sectors, even if that is bigger than request_alignment */
+    align = MAX(bs->bl.request_alignment, BDRV_SECTOR_SIZE);
+    aligned_offset = QEMU_ALIGN_DOWN(offset, align);
+    aligned_bytes = ROUND_UP(offset + bytes, align) - aligned_offset;
+
+    {
+        int count; /* sectors */
+        int64_t longret;
+
+        assert(QEMU_IS_ALIGNED(aligned_offset | aligned_bytes,
+                               BDRV_SECTOR_SIZE));
+        /*
+         * The contract allows us to return pnum smaller than bytes, even
+         * if the next query would see the same status; we truncate the
+         * request to avoid overflowing the driver's 32-bit interface.
+         */
+        longret = bs->drv->bdrv_co_get_block_status(
+            bs, aligned_offset >> BDRV_SECTOR_BITS,
+            MIN(INT_MAX, aligned_bytes) >> BDRV_SECTOR_BITS, &count,
+            &local_file);
+        if (longret < 0) {
+            assert(INT_MIN <= longret);
+            ret = longret;
+            goto out;
+        }
+        if (longret & BDRV_BLOCK_OFFSET_VALID) {
+            local_map = longret & BDRV_BLOCK_OFFSET_MASK;
+        }
+        ret = longret & ~BDRV_BLOCK_OFFSET_MASK;
+        *pnum = count * BDRV_SECTOR_SIZE;
+    }
+
+    /*
+     * The driver's result must be a multiple of request_alignment.
+     * Clamp pnum and adjust map to original request.
+     */
+    assert(QEMU_IS_ALIGNED(*pnum, align) && align > offset - aligned_offset);
+    *pnum -= offset - aligned_offset;
+    if (*pnum > bytes) {
+        *pnum = bytes;
+    }
+    if (ret & BDRV_BLOCK_OFFSET_VALID) {
+        local_map += offset - aligned_offset;
     }
 
     if (ret & BDRV_BLOCK_RAW) {
-        assert(ret & BDRV_BLOCK_OFFSET_VALID && *file);
-        ret = bdrv_co_get_block_status(*file, ret >> BDRV_SECTOR_BITS,
-                                       *pnum, pnum, file);
+        assert(ret & BDRV_BLOCK_OFFSET_VALID && local_file);
+        ret = bdrv_co_block_status(local_file, want_zero, local_map,
+                                   *pnum, pnum, &local_map, &local_file);
         goto out;
     }
 
     if (ret & (BDRV_BLOCK_DATA | BDRV_BLOCK_ZERO)) {
         ret |= BDRV_BLOCK_ALLOCATED;
-    } else {
+    } else if (want_zero) {
         if (bdrv_unallocated_blocks_are_zero(bs)) {
             ret |= BDRV_BLOCK_ZERO;
         } else if (bs->backing) {
             BlockDriverState *bs2 = bs->backing->bs;
-            int64_t nb_sectors2 = bdrv_nb_sectors(bs2);
-            if (nb_sectors2 >= 0 && sector_num >= nb_sectors2) {
+            int64_t size2 = bdrv_getlength(bs2);
+
+            if (size2 >= 0 && offset >= size2) {
                 ret |= BDRV_BLOCK_ZERO;
             }
         }
     }
 
-    if (*file && *file != bs &&
+    if (want_zero && local_file && local_file != bs &&
         (ret & BDRV_BLOCK_DATA) && !(ret & BDRV_BLOCK_ZERO) &&
         (ret & BDRV_BLOCK_OFFSET_VALID)) {
-        BlockDriverState *file2;
-        int file_pnum;
+        int64_t file_pnum;
+        int ret2;
 
-        ret2 = bdrv_co_get_block_status(*file, ret >> BDRV_SECTOR_BITS,
-                                        *pnum, &file_pnum, &file2);
+        ret2 = bdrv_co_block_status(local_file, want_zero, local_map,
+                                    *pnum, &file_pnum, NULL, NULL);
         if (ret2 >= 0) {
             /* Ignore errors.  This is just providing extra information, it
              * is useful but not necessary.
@@ -1924,26 +1978,36 @@ static int64_t coroutine_fn bdrv_co_get_block_status(BlockDriverState *bs,
 
 out:
     bdrv_dec_in_flight(bs);
-    if (ret >= 0 && sector_num + *pnum == total_sectors) {
+    if (ret >= 0 && offset + *pnum == total_size) {
         ret |= BDRV_BLOCK_EOF;
     }
+early_out:
+    if (file) {
+        *file = local_file;
+    }
+    if (map) {
+        *map = local_map;
+    }
     return ret;
 }
 
-static int64_t coroutine_fn bdrv_co_get_block_status_above(BlockDriverState *bs,
-        BlockDriverState *base,
-        int64_t sector_num,
-        int nb_sectors,
-        int *pnum,
-        BlockDriverState **file)
+static int coroutine_fn bdrv_co_block_status_above(BlockDriverState *bs,
+                                                   BlockDriverState *base,
+                                                   bool want_zero,
+                                                   int64_t offset,
+                                                   int64_t bytes,
+                                                   int64_t *pnum,
+                                                   int64_t *map,
+                                                   BlockDriverState **file)
 {
     BlockDriverState *p;
-    int64_t ret = 0;
+    int ret = 0;
     bool first = true;
 
     assert(bs != base);
     for (p = bs; p != base; p = backing_bs(p)) {
-        ret = bdrv_co_get_block_status(p, sector_num, nb_sectors, pnum, file);
+        ret = bdrv_co_block_status(p, want_zero, offset, bytes, pnum, map,
+                                   file);
         if (ret < 0) {
             break;
         }
@@ -1954,94 +2018,94 @@ static int64_t coroutine_fn bdrv_co_get_block_status_above(BlockDriverState *bs,
              * unallocated length we learned from an earlier
              * iteration.
              */
-            *pnum = nb_sectors;
+            *pnum = bytes;
         }
         if (ret & (BDRV_BLOCK_ZERO | BDRV_BLOCK_DATA)) {
             break;
         }
-        /* [sector_num, pnum] unallocated on this layer, which could be only
-         * the first part of [sector_num, nb_sectors].  */
-        nb_sectors = MIN(nb_sectors, *pnum);
+        /* [offset, pnum] unallocated on this layer, which could be only
+         * the first part of [offset, bytes].  */
+        bytes = MIN(bytes, *pnum);
         first = false;
     }
     return ret;
 }
 
-/* Coroutine wrapper for bdrv_get_block_status_above() */
-static void coroutine_fn bdrv_get_block_status_above_co_entry(void *opaque)
+/* Coroutine wrapper for bdrv_block_status_above() */
+static void coroutine_fn bdrv_block_status_above_co_entry(void *opaque)
 {
-    BdrvCoGetBlockStatusData *data = opaque;
+    BdrvCoBlockStatusData *data = opaque;
 
-    data->ret = bdrv_co_get_block_status_above(data->bs, data->base,
-                                               data->sector_num,
-                                               data->nb_sectors,
-                                               data->pnum,
-                                               data->file);
+    data->ret = bdrv_co_block_status_above(data->bs, data->base,
+                                           data->want_zero,
+                                           data->offset, data->bytes,
+                                           data->pnum, data->map, data->file);
     data->done = true;
 }
 
 /*
- * Synchronous wrapper around bdrv_co_get_block_status_above().
+ * Synchronous wrapper around bdrv_co_block_status_above().
  *
- * See bdrv_co_get_block_status_above() for details.
+ * See bdrv_co_block_status_above() for details.
  */
-int64_t bdrv_get_block_status_above(BlockDriverState *bs,
-                                    BlockDriverState *base,
-                                    int64_t sector_num,
-                                    int nb_sectors, int *pnum,
-                                    BlockDriverState **file)
+static int bdrv_common_block_status_above(BlockDriverState *bs,
+                                          BlockDriverState *base,
+                                          bool want_zero, int64_t offset,
+                                          int64_t bytes, int64_t *pnum,
+                                          int64_t *map,
+                                          BlockDriverState **file)
 {
     Coroutine *co;
-    BdrvCoGetBlockStatusData data = {
+    BdrvCoBlockStatusData data = {
         .bs = bs,
         .base = base,
-        .file = file,
-        .sector_num = sector_num,
-        .nb_sectors = nb_sectors,
+        .want_zero = want_zero,
+        .offset = offset,
+        .bytes = bytes,
         .pnum = pnum,
+        .map = map,
+        .file = file,
         .done = false,
     };
 
     if (qemu_in_coroutine()) {
         /* Fast-path if already in coroutine context */
-        bdrv_get_block_status_above_co_entry(&data);
+        bdrv_block_status_above_co_entry(&data);
     } else {
-        co = qemu_coroutine_create(bdrv_get_block_status_above_co_entry,
-                                   &data);
+        co = qemu_coroutine_create(bdrv_block_status_above_co_entry, &data);
         bdrv_coroutine_enter(bs, co);
         BDRV_POLL_WHILE(bs, !data.done);
     }
     return data.ret;
 }
 
-int64_t bdrv_get_block_status(BlockDriverState *bs,
-                              int64_t sector_num,
-                              int nb_sectors, int *pnum,
-                              BlockDriverState **file)
+int bdrv_block_status_above(BlockDriverState *bs, BlockDriverState *base,
+                            int64_t offset, int64_t bytes, int64_t *pnum,
+                            int64_t *map, BlockDriverState **file)
 {
-    return bdrv_get_block_status_above(bs, backing_bs(bs),
-                                       sector_num, nb_sectors, pnum, file);
+    return bdrv_common_block_status_above(bs, base, true, offset, bytes,
+                                          pnum, map, file);
+}
+
+int bdrv_block_status(BlockDriverState *bs, int64_t offset, int64_t bytes,
+                      int64_t *pnum, int64_t *map, BlockDriverState **file)
+{
+    return bdrv_block_status_above(bs, backing_bs(bs),
+                                   offset, bytes, pnum, map, file);
 }
 
 int coroutine_fn bdrv_is_allocated(BlockDriverState *bs, int64_t offset,
                                    int64_t bytes, int64_t *pnum)
 {
-    BlockDriverState *file;
-    int64_t sector_num = offset >> BDRV_SECTOR_BITS;
-    int nb_sectors = bytes >> BDRV_SECTOR_BITS;
-    int64_t ret;
-    int psectors;
+    int ret;
+    int64_t dummy;
 
-    assert(QEMU_IS_ALIGNED(offset, BDRV_SECTOR_SIZE));
-    assert(QEMU_IS_ALIGNED(bytes, BDRV_SECTOR_SIZE) && bytes < INT_MAX);
-    ret = bdrv_get_block_status(bs, sector_num, nb_sectors, &psectors,
-                                &file);
+    ret = bdrv_common_block_status_above(bs, backing_bs(bs), false, offset,
+                                         bytes, pnum ? pnum : &dummy, NULL,
+                                         NULL);
     if (ret < 0) {
         return ret;
     }
-    if (pnum) {
-        *pnum = psectors * BDRV_SECTOR_SIZE;
-    }
     return !!(ret & BDRV_BLOCK_ALLOCATED);
 }
 
diff --git a/block/mirror.c b/block/mirror.c
index 153758ca9f..307b6391a8 100644
--- a/block/mirror.c
+++ b/block/mirror.c
@@ -190,10 +190,9 @@ static int mirror_cow_align(MirrorBlockJob *s, int64_t *offset,
     bool need_cow;
     int ret = 0;
     int64_t align_offset = *offset;
-    unsigned int align_bytes = *bytes;
+    int64_t align_bytes = *bytes;
     int max_bytes = s->granularity * s->max_iov;
 
-    assert(*bytes < INT_MAX);
     need_cow = !test_bit(*offset / s->granularity, s->cow_bitmap);
     need_cow |= !test_bit((*offset + *bytes - 1) / s->granularity,
                           s->cow_bitmap);
@@ -329,7 +328,6 @@ static uint64_t coroutine_fn mirror_iteration(MirrorBlockJob *s)
     uint64_t delay_ns = 0;
     /* At least the first dirty chunk is mirrored in one iteration. */
     int nb_chunks = 1;
-    int sectors_per_chunk = s->granularity >> BDRV_SECTOR_BITS;
     bool write_zeroes_ok = bdrv_can_write_zeroes_with_unmap(blk_bs(s->target));
     int max_io_bytes = MAX(s->buf_size / MAX_IN_FLIGHT, MAX_IO_BYTES);
 
@@ -377,7 +375,7 @@ static uint64_t coroutine_fn mirror_iteration(MirrorBlockJob *s)
     }
 
     /* Clear dirty bits before querying the block status, because
-     * calling bdrv_get_block_status_above could yield - if some blocks are
+     * calling bdrv_block_status_above could yield - if some blocks are
      * marked dirty in this window, we need to know.
      */
     bdrv_reset_dirty_bitmap_locked(s->dirty_bitmap, offset,
@@ -386,11 +384,9 @@ static uint64_t coroutine_fn mirror_iteration(MirrorBlockJob *s)
 
     bitmap_set(s->in_flight_bitmap, offset / s->granularity, nb_chunks);
     while (nb_chunks > 0 && offset < s->bdev_length) {
-        int64_t ret;
-        int io_sectors;
-        unsigned int io_bytes;
+        int ret;
+        int64_t io_bytes;
         int64_t io_bytes_acct;
-        BlockDriverState *file;
         enum MirrorMethod {
             MIRROR_METHOD_COPY,
             MIRROR_METHOD_ZERO,
@@ -398,11 +394,9 @@ static uint64_t coroutine_fn mirror_iteration(MirrorBlockJob *s)
         } mirror_method = MIRROR_METHOD_COPY;
 
         assert(!(offset % s->granularity));
-        ret = bdrv_get_block_status_above(source, NULL,
-                                          offset >> BDRV_SECTOR_BITS,
-                                          nb_chunks * sectors_per_chunk,
-                                          &io_sectors, &file);
-        io_bytes = io_sectors * BDRV_SECTOR_SIZE;
+        ret = bdrv_block_status_above(source, NULL, offset,
+                                      nb_chunks * s->granularity,
+                                      &io_bytes, NULL, NULL);
         if (ret < 0) {
             io_bytes = MIN(nb_chunks * s->granularity, max_io_bytes);
         } else if (ret & BDRV_BLOCK_DATA) {
@@ -414,7 +408,7 @@ static uint64_t coroutine_fn mirror_iteration(MirrorBlockJob *s)
             io_bytes = s->granularity;
         } else if (ret >= 0 && !(ret & BDRV_BLOCK_DATA)) {
             int64_t target_offset;
-            unsigned int target_bytes;
+            int64_t target_bytes;
             bdrv_round_to_clusters(blk_bs(s->target), offset, io_bytes,
                                    &target_offset, &target_bytes);
             if (target_offset == offset &&
@@ -1133,9 +1127,7 @@ static void mirror_start_job(const char *job_id, BlockDriverState *bs,
         granularity = bdrv_get_default_bitmap_granularity(target);
     }
 
-    assert ((granularity & (granularity - 1)) == 0);
-    /* Granularity must be large enough for sector-based dirty bitmap */
-    assert(granularity >= BDRV_SECTOR_SIZE);
+    assert(is_power_of_2(granularity));
 
     if (buf_size < 0) {
         error_setg(errp, "Invalid parameter 'buf-size'");
diff --git a/block/qcow2-cluster.c b/block/qcow2-cluster.c
index 0e5aec81cb..fb10e26068 100644
--- a/block/qcow2-cluster.c
+++ b/block/qcow2-cluster.c
@@ -1632,7 +1632,7 @@ static int discard_single_l2(BlockDriverState *bs, uint64_t offset,
          * cluster is already marked as zero, or if it's unallocated and we
          * don't have a backing file.
          *
-         * TODO We might want to use bdrv_get_block_status(bs) here, but we're
+         * TODO We might want to use bdrv_block_status(bs) here, but we're
          * holding s->lock, so that doesn't work today.
          *
          * If full_discard is true, the sector should not read back as zeroes,
diff --git a/block/qcow2.c b/block/qcow2.c
index f63d1831f8..92cb9f9bfa 100644
--- a/block/qcow2.c
+++ b/block/qcow2.c
@@ -1139,7 +1139,7 @@ static int qcow2_do_open(BlockDriverState *bs, QDict *options, int flags,
 
     s->cluster_bits = header.cluster_bits;
     s->cluster_size = 1 << s->cluster_bits;
-    s->cluster_sectors = 1 << (s->cluster_bits - 9);
+    s->cluster_sectors = 1 << (s->cluster_bits - BDRV_SECTOR_BITS);
 
     /* Initialise version 3 header fields */
     if (header.version == 2) {
@@ -1636,7 +1636,7 @@ static int64_t coroutine_fn qcow2_co_get_block_status(BlockDriverState *bs,
 
     bytes = MIN(INT_MAX, nb_sectors * BDRV_SECTOR_SIZE);
     qemu_co_mutex_lock(&s->lock);
-    ret = qcow2_get_cluster_offset(bs, sector_num << 9, &bytes,
+    ret = qcow2_get_cluster_offset(bs, sector_num << BDRV_SECTOR_BITS, &bytes,
                                    &cluster_offset);
     qemu_co_mutex_unlock(&s->lock);
     if (ret < 0) {
@@ -2460,6 +2460,14 @@ static int qcow2_set_up_encryption(BlockDriverState *bs, const char *encryptfmt,
 }
 
 
+typedef struct PreallocCo {
+    BlockDriverState *bs;
+    uint64_t offset;
+    uint64_t new_length;
+
+    int ret;
+} PreallocCo;
+
 /**
  * Preallocates metadata structures for data clusters between @offset (in the
  * guest disk) and @new_length (which is thus generally the new guest disk
@@ -2467,9 +2475,12 @@ static int qcow2_set_up_encryption(BlockDriverState *bs, const char *encryptfmt,
  *
  * Returns: 0 on success, -errno on failure.
  */
-static int preallocate(BlockDriverState *bs,
-                       uint64_t offset, uint64_t new_length)
+static void coroutine_fn preallocate_co(void *opaque)
 {
+    PreallocCo *params = opaque;
+    BlockDriverState *bs = params->bs;
+    uint64_t offset = params->offset;
+    uint64_t new_length = params->new_length;
     BDRVQcow2State *s = bs->opaque;
     uint64_t bytes;
     uint64_t host_offset = 0;
@@ -2477,9 +2488,7 @@ static int preallocate(BlockDriverState *bs,
     int ret;
     QCowL2Meta *meta;
 
-    if (qemu_in_coroutine()) {
-        qemu_co_mutex_lock(&s->lock);
-    }
+    qemu_co_mutex_lock(&s->lock);
 
     assert(offset <= new_length);
     bytes = new_length - offset;
@@ -2533,10 +2542,28 @@ static int preallocate(BlockDriverState *bs,
     ret = 0;
 
 done:
+    qemu_co_mutex_unlock(&s->lock);
+    params->ret = ret;
+}
+
+static int preallocate(BlockDriverState *bs,
+                       uint64_t offset, uint64_t new_length)
+{
+    PreallocCo params = {
+        .bs         = bs,
+        .offset     = offset,
+        .new_length = new_length,
+        .ret        = -EINPROGRESS,
+    };
+
     if (qemu_in_coroutine()) {
-        qemu_co_mutex_unlock(&s->lock);
+        preallocate_co(&params);
+    } else {
+        Coroutine *co = qemu_coroutine_create(preallocate_co, &params);
+        bdrv_coroutine_enter(bs, co);
+        BDRV_POLL_WHILE(bs, params.ret == -EINPROGRESS);
     }
-    return ret;
+    return params.ret;
 }
 
 /* qcow2_refcount_metadata_size:
@@ -2972,23 +2999,21 @@ finish:
 }
 
 
-static bool is_zero_sectors(BlockDriverState *bs, int64_t start,
-                            uint32_t count)
+static bool is_zero(BlockDriverState *bs, int64_t offset, int64_t bytes)
 {
-    int nr;
-    BlockDriverState *file;
-    int64_t res;
+    int64_t nr;
+    int res;
 
-    if (start + count > bs->total_sectors) {
-        count = bs->total_sectors - start;
+    /* Clamp to image length, before checking status of underlying sectors */
+    if (offset + bytes > bs->total_sectors * BDRV_SECTOR_SIZE) {
+        bytes = bs->total_sectors * BDRV_SECTOR_SIZE - offset;
     }
 
-    if (!count) {
+    if (!bytes) {
         return true;
     }
-    res = bdrv_get_block_status_above(bs, NULL, start, count,
-                                      &nr, &file);
-    return res >= 0 && (res & BDRV_BLOCK_ZERO) && nr == count;
+    res = bdrv_block_status_above(bs, NULL, offset, bytes, &nr, NULL, NULL);
+    return res >= 0 && (res & BDRV_BLOCK_ZERO) && nr == bytes;
 }
 
 static coroutine_fn int qcow2_co_pwrite_zeroes(BlockDriverState *bs,
@@ -3006,24 +3031,21 @@ static coroutine_fn int qcow2_co_pwrite_zeroes(BlockDriverState *bs,
     }
 
     if (head || tail) {
-        int64_t cl_start = (offset - head) >> BDRV_SECTOR_BITS;
         uint64_t off;
         unsigned int nr;
 
         assert(head + bytes <= s->cluster_size);
 
         /* check whether remainder of cluster already reads as zero */
-        if (!(is_zero_sectors(bs, cl_start,
-                              DIV_ROUND_UP(head, BDRV_SECTOR_SIZE)) &&
-              is_zero_sectors(bs, (offset + bytes) >> BDRV_SECTOR_BITS,
-                              DIV_ROUND_UP(-tail & (s->cluster_size - 1),
-                                           BDRV_SECTOR_SIZE)))) {
+        if (!(is_zero(bs, offset - head, head) &&
+              is_zero(bs, offset + bytes,
+                      tail ? s->cluster_size - tail : 0))) {
             return -ENOTSUP;
         }
 
         qemu_co_mutex_lock(&s->lock);
         /* We can have new write after previous check */
-        offset = cl_start << BDRV_SECTOR_BITS;
+        offset = QEMU_ALIGN_DOWN(offset, s->cluster_size);
         bytes = s->cluster_size;
         nr = s->cluster_size;
         ret = qcow2_get_cluster_offset(bs, offset, &nr, &off);
@@ -3150,12 +3172,13 @@ static int qcow2_truncate(BlockDriverState *bs, int64_t offset,
             return last_cluster;
         }
         if ((last_cluster + 1) * s->cluster_size < old_file_size) {
-            ret = bdrv_truncate(bs->file, (last_cluster + 1) * s->cluster_size,
-                                PREALLOC_MODE_OFF, NULL);
-            if (ret < 0) {
-                warn_report("Failed to truncate the tail of the image: %s",
-                            strerror(-ret));
-                ret = 0;
+            Error *local_err = NULL;
+
+            bdrv_truncate(bs->file, (last_cluster + 1) * s->cluster_size,
+                          PREALLOC_MODE_OFF, &local_err);
+            if (local_err) {
+                warn_reportf_err(local_err,
+                                 "Failed to truncate the tail of the image: ");
             }
         }
     } else {
@@ -3192,6 +3215,7 @@ static int qcow2_truncate(BlockDriverState *bs, int64_t offset,
                              "Failed to inquire current file length");
             return old_file_size;
         }
+        old_file_size = ROUND_UP(old_file_size, s->cluster_size);
 
         nb_new_data_clusters = DIV_ROUND_UP(offset - old_length,
                                             s->cluster_size);
@@ -3697,19 +3721,14 @@ static BlockMeasureInfo *qcow2_measure(QemuOpts *opts, BlockDriverState *in_bs,
             required = virtual_size;
         } else {
             int64_t offset;
-            int pnum = 0;
-
-            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,
-                                                  offset >> BDRV_SECTOR_BITS,
-                                                  nb_sectors,
-                                                  &pnum, &file);
+            int64_t pnum = 0;
+
+            for (offset = 0; offset < ssize; offset += pnum) {
+                int ret;
+
+                ret = bdrv_block_status_above(in_bs, NULL, offset,
+                                              ssize - offset, &pnum, NULL,
+                                              NULL);
                 if (ret < 0) {
                     error_setg_errno(&local_err, -ret,
                                      "Unable to get block status");
@@ -3721,11 +3740,10 @@ 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(offset + pnum * BDRV_SECTOR_SIZE,
-                                 cluster_size) - offset) >> BDRV_SECTOR_BITS;
+                    pnum = ROUND_UP(offset + pnum, cluster_size) - offset;
 
                     /* Count clusters we've seen */
-                    required += offset % cluster_size + pnum * BDRV_SECTOR_SIZE;
+                    required += offset % cluster_size + pnum;
                 }
             }
         }
diff --git a/block/trace-events b/block/trace-events
index 25dd5a3026..11c8d5f590 100644
--- a/block/trace-events
+++ b/block/trace-events
@@ -12,7 +12,7 @@ blk_co_pwritev(void *blk, void *bs, int64_t offset, unsigned int bytes, int flag
 bdrv_co_preadv(void *bs, int64_t offset, int64_t nbytes, unsigned int flags) "bs %p offset %"PRId64" nbytes %"PRId64" flags 0x%x"
 bdrv_co_pwritev(void *bs, int64_t offset, int64_t nbytes, unsigned int flags) "bs %p offset %"PRId64" nbytes %"PRId64" flags 0x%x"
 bdrv_co_pwrite_zeroes(void *bs, int64_t offset, int count, int flags) "bs %p offset %"PRId64" count %d flags 0x%x"
-bdrv_co_do_copy_on_readv(void *bs, int64_t offset, unsigned int bytes, int64_t cluster_offset, unsigned int cluster_bytes) "bs %p offset %"PRId64" bytes %u cluster_offset %"PRId64" cluster_bytes %u"
+bdrv_co_do_copy_on_readv(void *bs, int64_t offset, unsigned int bytes, int64_t cluster_offset, int64_t cluster_bytes) "bs %p offset %"PRId64" bytes %u cluster_offset %"PRId64" cluster_bytes %"PRId64
 
 # block/stream.c
 stream_one_iteration(void *s, int64_t offset, uint64_t bytes, int is_allocated) "s %p offset %" PRId64 " bytes %" PRIu64 " is_allocated %d"
diff --git a/include/block/block.h b/include/block/block.h
index d5c2731a03..fbc21daf62 100644
--- a/include/block/block.h
+++ b/include/block/block.h
@@ -121,7 +121,7 @@ typedef struct HDGeometry {
 #define BDRV_REQUEST_MAX_BYTES (BDRV_REQUEST_MAX_SECTORS << BDRV_SECTOR_BITS)
 
 /*
- * Allocation status flags for bdrv_get_block_status() and friends.
+ * Allocation status flags for bdrv_block_status() and friends.
  *
  * Public flags:
  * BDRV_BLOCK_DATA: allocation for data at offset is tied to this layer
@@ -136,10 +136,11 @@ typedef struct HDGeometry {
  *                 that the block layer recompute the answer from the returned
  *                 BDS; must be accompanied by just BDRV_BLOCK_OFFSET_VALID.
  *
- * If BDRV_BLOCK_OFFSET_VALID is set, bits 9-62 (BDRV_BLOCK_OFFSET_MASK)
- * represent the offset in the returned BDS that is allocated for the
- * corresponding raw data; however, whether that offset actually contains
- * data also depends on BDRV_BLOCK_DATA and BDRV_BLOCK_ZERO, as follows:
+ * If BDRV_BLOCK_OFFSET_VALID is set, bits 9-62 (BDRV_BLOCK_OFFSET_MASK) of
+ * the return value (old interface) or the entire map parameter (new
+ * interface) represent the offset in the returned BDS that is allocated for
+ * the corresponding raw data.  However, whether that offset actually
+ * contains data also depends on BDRV_BLOCK_DATA, as follows:
  *
  * DATA ZERO OFFSET_VALID
  *  t    t        t       sectors read as zero, returned file is zero at offset
@@ -421,14 +422,12 @@ int bdrv_has_zero_init_1(BlockDriverState *bs);
 int bdrv_has_zero_init(BlockDriverState *bs);
 bool bdrv_unallocated_blocks_are_zero(BlockDriverState *bs);
 bool bdrv_can_write_zeroes_with_unmap(BlockDriverState *bs);
-int64_t bdrv_get_block_status(BlockDriverState *bs, int64_t sector_num,
-                              int nb_sectors, int *pnum,
-                              BlockDriverState **file);
-int64_t bdrv_get_block_status_above(BlockDriverState *bs,
-                                    BlockDriverState *base,
-                                    int64_t sector_num,
-                                    int nb_sectors, int *pnum,
-                                    BlockDriverState **file);
+int bdrv_block_status(BlockDriverState *bs, int64_t offset,
+                      int64_t bytes, int64_t *pnum, int64_t *map,
+                      BlockDriverState **file);
+int bdrv_block_status_above(BlockDriverState *bs, BlockDriverState *base,
+                            int64_t offset, int64_t bytes, int64_t *pnum,
+                            int64_t *map, BlockDriverState **file);
 int bdrv_is_allocated(BlockDriverState *bs, int64_t offset, int64_t bytes,
                       int64_t *pnum);
 int bdrv_is_allocated_above(BlockDriverState *top, BlockDriverState *base,
@@ -474,9 +473,9 @@ int bdrv_get_flags(BlockDriverState *bs);
 int bdrv_get_info(BlockDriverState *bs, BlockDriverInfo *bdi);
 ImageInfoSpecific *bdrv_get_specific_info(BlockDriverState *bs);
 void bdrv_round_to_clusters(BlockDriverState *bs,
-                            int64_t offset, unsigned int bytes,
+                            int64_t offset, int64_t bytes,
                             int64_t *cluster_offset,
-                            unsigned int *cluster_bytes);
+                            int64_t *cluster_bytes);
 
 const char *bdrv_get_encrypted_filename(BlockDriverState *bs);
 void bdrv_get_backing_filename(BlockDriverState *bs,
diff --git a/include/block/block_int.h b/include/block/block_int.h
index 885c08e989..a5482775ec 100644
--- a/include/block/block_int.h
+++ b/include/block/block_int.h
@@ -202,10 +202,13 @@ struct BlockDriver {
         int64_t offset, int bytes);
 
     /*
-     * Building block for bdrv_block_status[_above]. The driver should
-     * answer only according to the current layer, and should not
-     * set BDRV_BLOCK_ALLOCATED, but may set BDRV_BLOCK_RAW.  See block.h
-     * for the meaning of _DATA, _ZERO, and _OFFSET_VALID.
+     * Building block for bdrv_block_status[_above] and
+     * bdrv_is_allocated[_above].  The driver should answer only
+     * according to the current layer, and should not set
+     * BDRV_BLOCK_ALLOCATED, but may set BDRV_BLOCK_RAW.  See block.h
+     * for the meaning of _DATA, _ZERO, and _OFFSET_VALID.  The block
+     * layer guarantees input aligned to request_alignment, as well as
+     * non-NULL pnum and file.
      */
     int64_t coroutine_fn (*bdrv_co_get_block_status)(BlockDriverState *bs,
         int64_t sector_num, int nb_sectors, int *pnum,
diff --git a/qemu-img.c b/qemu-img.c
index d6007b2a6d..02a6e27beb 100644
--- a/qemu-img.c
+++ b/qemu-img.c
@@ -1065,6 +1065,28 @@ done:
 }
 
 /*
+ * Returns -1 if 'buf' contains only zeroes, otherwise the byte index
+ * of the first sector boundary within buf where the sector contains a
+ * non-zero byte.  This function is robust to a buffer that is not
+ * sector-aligned.
+ */
+static int64_t find_nonzero(const uint8_t *buf, int64_t n)
+{
+    int64_t i;
+    int64_t end = QEMU_ALIGN_DOWN(n, BDRV_SECTOR_SIZE);
+
+    for (i = 0; i < end; i += BDRV_SECTOR_SIZE) {
+        if (!buffer_is_zero(buf + i, BDRV_SECTOR_SIZE)) {
+            return i;
+        }
+    }
+    if (i < n && !buffer_is_zero(buf + i, n - end)) {
+        return i;
+    }
+    return -1;
+}
+
+/*
  * Returns true iff the first sector pointed to by 'buf' contains at least
  * a non-NUL byte.
  *
@@ -1134,31 +1156,28 @@ static int is_allocated_sectors_min(const uint8_t *buf, int n, int *pnum,
 }
 
 /*
- * Compares two buffers sector by sector. Returns 0 if the first sector of both
- * buffers matches, non-zero otherwise.
+ * Compares two buffers sector by sector. Returns 0 if the first
+ * sector of each buffer matches, non-zero otherwise.
  *
- * pnum is set to the number of sectors (including and immediately following
- * the first one) that are known to have the same comparison result
+ * pnum is set to the sector-aligned size of the buffer prefix that
+ * has the same matching status as the first sector.
  */
-static int compare_sectors(const uint8_t *buf1, const uint8_t *buf2, int n,
-    int *pnum)
+static int compare_buffers(const uint8_t *buf1, const uint8_t *buf2,
+                           int64_t bytes, int64_t *pnum)
 {
     bool res;
-    int i;
+    int64_t i = MIN(bytes, BDRV_SECTOR_SIZE);
 
-    if (n <= 0) {
-        *pnum = 0;
-        return 0;
-    }
+    assert(bytes > 0);
 
-    res = !!memcmp(buf1, buf2, 512);
-    for(i = 1; i < n; i++) {
-        buf1 += 512;
-        buf2 += 512;
+    res = !!memcmp(buf1, buf2, i);
+    while (i < bytes) {
+        int64_t len = MIN(bytes - i, BDRV_SECTOR_SIZE);
 
-        if (!!memcmp(buf1, buf2, 512) != res) {
+        if (!!memcmp(buf1 + i, buf2 + i, len) != res) {
             break;
         }
+        i += len;
     }
 
     *pnum = i;
@@ -1167,45 +1186,38 @@ static int compare_sectors(const uint8_t *buf1, const uint8_t *buf2, int n,
 
 #define IO_BUF_SIZE (2 * 1024 * 1024)
 
-static int64_t sectors_to_bytes(int64_t sectors)
-{
-    return sectors << BDRV_SECTOR_BITS;
-}
-
-static int64_t sectors_to_process(int64_t total, int64_t from)
-{
-    return MIN(total - from, IO_BUF_SIZE >> BDRV_SECTOR_BITS);
-}
-
 /*
  * Check if passed sectors are empty (not allocated or contain only 0 bytes)
  *
- * Returns 0 in case sectors are filled with 0, 1 if sectors contain non-zero
- * data and negative value on error.
+ * Intended for use by 'qemu-img compare': Returns 0 in case sectors are
+ * filled with 0, 1 if sectors contain non-zero data (this is a comparison
+ * failure), and 4 on error (the exit status for read errors), after emitting
+ * an error message.
  *
  * @param blk:  BlockBackend for the image
- * @param sect_num: Number of first sector to check
- * @param sect_count: Number of sectors to check
+ * @param offset: Starting offset to check
+ * @param bytes: Number of bytes to check
  * @param filename: Name of disk file we are checking (logging purpose)
  * @param buffer: Allocated buffer for storing read data
  * @param quiet: Flag for quiet mode
  */
-static int check_empty_sectors(BlockBackend *blk, int64_t sect_num,
-                               int sect_count, const char *filename,
+static int check_empty_sectors(BlockBackend *blk, int64_t offset,
+                               int64_t bytes, const char *filename,
                                uint8_t *buffer, bool quiet)
 {
-    int pnum, ret = 0;
-    ret = blk_pread(blk, sect_num << BDRV_SECTOR_BITS, buffer,
-                    sect_count << BDRV_SECTOR_BITS);
+    int ret = 0;
+    int64_t idx;
+
+    ret = blk_pread(blk, offset, buffer, bytes);
     if (ret < 0) {
         error_report("Error while reading offset %" PRId64 " of %s: %s",
-                     sectors_to_bytes(sect_num), filename, strerror(-ret));
-        return ret;
+                     offset, filename, strerror(-ret));
+        return 4;
     }
-    ret = is_allocated_sectors(buffer, sect_count, &pnum);
-    if (ret || pnum != sect_count) {
+    idx = find_nonzero(buffer, bytes);
+    if (idx >= 0) {
         qprintf(quiet, "Content mismatch at offset %" PRId64 "!\n",
-                sectors_to_bytes(ret ? sect_num : sect_num + pnum));
+                offset + idx);
         return 1;
     }
 
@@ -1224,18 +1236,18 @@ static int img_compare(int argc, char **argv)
     const char *fmt1 = NULL, *fmt2 = NULL, *cache, *filename1, *filename2;
     BlockBackend *blk1, *blk2;
     BlockDriverState *bs1, *bs2;
-    int64_t total_sectors1, total_sectors2;
+    int64_t total_size1, total_size2;
     uint8_t *buf1 = NULL, *buf2 = NULL;
-    int pnum1, pnum2;
+    int64_t pnum1, pnum2;
     int allocated1, allocated2;
     int ret = 0; /* return value - 0 Ident, 1 Different, >1 Error */
     bool progress = false, quiet = false, strict = false;
     int flags;
     bool writethrough;
-    int64_t total_sectors;
-    int64_t sector_num = 0;
-    int64_t nb_sectors;
-    int c, pnum;
+    int64_t total_size;
+    int64_t offset = 0;
+    int64_t chunk;
+    int c;
     uint64_t progress_base;
     bool image_opts = false;
     bool force_share = false;
@@ -1348,42 +1360,37 @@ static int img_compare(int argc, char **argv)
 
     buf1 = blk_blockalign(blk1, IO_BUF_SIZE);
     buf2 = blk_blockalign(blk2, IO_BUF_SIZE);
-    total_sectors1 = blk_nb_sectors(blk1);
-    if (total_sectors1 < 0) {
+    total_size1 = blk_getlength(blk1);
+    if (total_size1 < 0) {
         error_report("Can't get size of %s: %s",
-                     filename1, strerror(-total_sectors1));
+                     filename1, strerror(-total_size1));
         ret = 4;
         goto out;
     }
-    total_sectors2 = blk_nb_sectors(blk2);
-    if (total_sectors2 < 0) {
+    total_size2 = blk_getlength(blk2);
+    if (total_size2 < 0) {
         error_report("Can't get size of %s: %s",
-                     filename2, strerror(-total_sectors2));
+                     filename2, strerror(-total_size2));
         ret = 4;
         goto out;
     }
-    total_sectors = MIN(total_sectors1, total_sectors2);
-    progress_base = MAX(total_sectors1, total_sectors2);
+    total_size = MIN(total_size1, total_size2);
+    progress_base = MAX(total_size1, total_size2);
 
     qemu_progress_print(0, 100);
 
-    if (strict && total_sectors1 != total_sectors2) {
+    if (strict && total_size1 != total_size2) {
         ret = 1;
         qprintf(quiet, "Strict mode: Image size mismatch!\n");
         goto out;
     }
 
-    for (;;) {
-        int64_t status1, status2;
-        BlockDriverState *file;
+    while (offset < total_size) {
+        int status1, status2;
 
-        nb_sectors = sectors_to_process(total_sectors, sector_num);
-        if (nb_sectors <= 0) {
-            break;
-        }
-        status1 = bdrv_get_block_status_above(bs1, NULL, sector_num,
-                                              total_sectors1 - sector_num,
-                                              &pnum1, &file);
+        status1 = bdrv_block_status_above(bs1, NULL, offset,
+                                          total_size1 - offset, &pnum1, NULL,
+                                          NULL);
         if (status1 < 0) {
             ret = 3;
             error_report("Sector allocation test failed for %s", filename1);
@@ -1391,112 +1398,92 @@ static int img_compare(int argc, char **argv)
         }
         allocated1 = status1 & BDRV_BLOCK_ALLOCATED;
 
-        status2 = bdrv_get_block_status_above(bs2, NULL, sector_num,
-                                              total_sectors2 - sector_num,
-                                              &pnum2, &file);
+        status2 = bdrv_block_status_above(bs2, NULL, offset,
+                                          total_size2 - offset, &pnum2, NULL,
+                                          NULL);
         if (status2 < 0) {
             ret = 3;
             error_report("Sector allocation test failed for %s", filename2);
             goto out;
         }
         allocated2 = status2 & BDRV_BLOCK_ALLOCATED;
-        if (pnum1) {
-            nb_sectors = MIN(nb_sectors, pnum1);
-        }
-        if (pnum2) {
-            nb_sectors = MIN(nb_sectors, pnum2);
-        }
+
+        assert(pnum1 && pnum2);
+        chunk = MIN(pnum1, pnum2);
 
         if (strict) {
-            if ((status1 & ~BDRV_BLOCK_OFFSET_MASK) !=
-                (status2 & ~BDRV_BLOCK_OFFSET_MASK)) {
+            if (status1 != status2) {
                 ret = 1;
                 qprintf(quiet, "Strict mode: Offset %" PRId64
-                        " block status mismatch!\n",
-                        sectors_to_bytes(sector_num));
+                        " block status mismatch!\n", offset);
                 goto out;
             }
         }
         if ((status1 & BDRV_BLOCK_ZERO) && (status2 & BDRV_BLOCK_ZERO)) {
-            nb_sectors = MIN(pnum1, pnum2);
+            /* nothing to do */
         } else if (allocated1 == allocated2) {
             if (allocated1) {
-                ret = blk_pread(blk1, sector_num << BDRV_SECTOR_BITS, buf1,
-                                nb_sectors << BDRV_SECTOR_BITS);
+                int64_t pnum;
+
+                chunk = MIN(chunk, IO_BUF_SIZE);
+                ret = blk_pread(blk1, offset, buf1, chunk);
                 if (ret < 0) {
-                    error_report("Error while reading offset %" PRId64 " of %s:"
-                                 " %s", sectors_to_bytes(sector_num), filename1,
-                                 strerror(-ret));
+                    error_report("Error while reading offset %" PRId64
+                                 " of %s: %s",
+                                 offset, filename1, strerror(-ret));
                     ret = 4;
                     goto out;
                 }
-                ret = blk_pread(blk2, sector_num << BDRV_SECTOR_BITS, buf2,
-                                nb_sectors << BDRV_SECTOR_BITS);
+                ret = blk_pread(blk2, offset, buf2, chunk);
                 if (ret < 0) {
                     error_report("Error while reading offset %" PRId64
-                                 " of %s: %s", sectors_to_bytes(sector_num),
-                                 filename2, strerror(-ret));
+                                 " of %s: %s",
+                                 offset, filename2, strerror(-ret));
                     ret = 4;
                     goto out;
                 }
-                ret = compare_sectors(buf1, buf2, nb_sectors, &pnum);
-                if (ret || pnum != nb_sectors) {
+                ret = compare_buffers(buf1, buf2, chunk, &pnum);
+                if (ret || pnum != chunk) {
                     qprintf(quiet, "Content mismatch at offset %" PRId64 "!\n",
-                            sectors_to_bytes(
-                                ret ? sector_num : sector_num + pnum));
+                            offset + (ret ? 0 : pnum));
                     ret = 1;
                     goto out;
                 }
             }
         } else {
-
+            chunk = MIN(chunk, IO_BUF_SIZE);
             if (allocated1) {
-                ret = check_empty_sectors(blk1, sector_num, nb_sectors,
+                ret = check_empty_sectors(blk1, offset, chunk,
                                           filename1, buf1, quiet);
             } else {
-                ret = check_empty_sectors(blk2, sector_num, nb_sectors,
+                ret = check_empty_sectors(blk2, offset, chunk,
                                           filename2, buf1, quiet);
             }
             if (ret) {
-                if (ret < 0) {
-                    error_report("Error while reading offset %" PRId64 ": %s",
-                                 sectors_to_bytes(sector_num), strerror(-ret));
-                    ret = 4;
-                }
                 goto out;
             }
         }
-        sector_num += nb_sectors;
-        qemu_progress_print(((float) nb_sectors / progress_base)*100, 100);
+        offset += chunk;
+        qemu_progress_print(((float) chunk / progress_base) * 100, 100);
     }
 
-    if (total_sectors1 != total_sectors2) {
+    if (total_size1 != total_size2) {
         BlockBackend *blk_over;
-        int64_t total_sectors_over;
         const char *filename_over;
 
         qprintf(quiet, "Warning: Image size mismatch!\n");
-        if (total_sectors1 > total_sectors2) {
-            total_sectors_over = total_sectors1;
+        if (total_size1 > total_size2) {
             blk_over = blk1;
             filename_over = filename1;
         } else {
-            total_sectors_over = total_sectors2;
             blk_over = blk2;
             filename_over = filename2;
         }
 
-        for (;;) {
-            int64_t count;
-
-            nb_sectors = sectors_to_process(total_sectors_over, sector_num);
-            if (nb_sectors <= 0) {
-                break;
-            }
-            ret = bdrv_is_allocated_above(blk_bs(blk_over), NULL,
-                                          sector_num * BDRV_SECTOR_SIZE,
-                                          nb_sectors * BDRV_SECTOR_SIZE,
-                                          &count);
+        while (offset < progress_base) {
+            ret = bdrv_block_status_above(blk_bs(blk_over), NULL, offset,
+                                          progress_base - offset, &chunk,
+                                          NULL, NULL);
             if (ret < 0) {
                 ret = 3;
                 error_report("Sector allocation test failed for %s",
@@ -1504,25 +1491,16 @@ static int img_compare(int argc, char **argv)
                 goto out;
 
             }
-            /* TODO relax this once bdrv_is_allocated_above does not enforce
-             * sector alignment */
-            assert(QEMU_IS_ALIGNED(count, BDRV_SECTOR_SIZE));
-            nb_sectors = count >> BDRV_SECTOR_BITS;
-            if (ret) {
-                ret = check_empty_sectors(blk_over, sector_num, nb_sectors,
+            if (ret & BDRV_BLOCK_ALLOCATED && !(ret & BDRV_BLOCK_ZERO)) {
+                chunk = MIN(chunk, IO_BUF_SIZE);
+                ret = check_empty_sectors(blk_over, offset, chunk,
                                           filename_over, buf1, quiet);
                 if (ret) {
-                    if (ret < 0) {
-                        error_report("Error while reading offset %" PRId64
-                                     " of %s: %s", sectors_to_bytes(sector_num),
-                                     filename_over, strerror(-ret));
-                        ret = 4;
-                    }
                     goto out;
                 }
             }
-            sector_num += nb_sectors;
-            qemu_progress_print(((float) nb_sectors / progress_base)*100, 100);
+            offset += chunk;
+            qemu_progress_print(((float) chunk / progress_base) * 100, 100);
         }
     }
 
@@ -1590,8 +1568,8 @@ static void convert_select_part(ImgConvertState *s, int64_t sector_num,
 
 static int convert_iteration_sectors(ImgConvertState *s, int64_t sector_num)
 {
-    int64_t ret, src_cur_offset;
-    int n, src_cur;
+    int64_t src_cur_offset;
+    int ret, n, src_cur;
 
     convert_select_part(s, sector_num, &src_cur, &src_cur_offset);
 
@@ -1599,19 +1577,24 @@ static int convert_iteration_sectors(ImgConvertState *s, int64_t sector_num)
     n = MIN(s->total_sectors - sector_num, BDRV_REQUEST_MAX_SECTORS);
 
     if (s->sector_next_status <= sector_num) {
-        BlockDriverState *file;
+        int64_t count = n * BDRV_SECTOR_SIZE;
+
         if (s->target_has_backing) {
-            ret = bdrv_get_block_status(blk_bs(s->src[src_cur]),
-                                        sector_num - src_cur_offset,
-                                        n, &n, &file);
+
+            ret = bdrv_block_status(blk_bs(s->src[src_cur]),
+                                    (sector_num - src_cur_offset) *
+                                    BDRV_SECTOR_SIZE,
+                                    count, &count, NULL, NULL);
         } else {
-            ret = bdrv_get_block_status_above(blk_bs(s->src[src_cur]), NULL,
-                                              sector_num - src_cur_offset,
-                                              n, &n, &file);
+            ret = bdrv_block_status_above(blk_bs(s->src[src_cur]), NULL,
+                                          (sector_num - src_cur_offset) *
+                                          BDRV_SECTOR_SIZE,
+                                          count, &count, NULL, NULL);
         }
         if (ret < 0) {
             return ret;
         }
+        n = DIV_ROUND_UP(count, BDRV_SECTOR_SIZE);
 
         if (ret & BDRV_BLOCK_ZERO) {
             s->status = BLK_ZERO;
@@ -2673,13 +2656,14 @@ static void dump_map_entry(OutputFormat output_format, MapEntry *e,
     }
 }
 
-static int get_block_status(BlockDriverState *bs, int64_t sector_num,
-                            int nb_sectors, MapEntry *e)
+static int get_block_status(BlockDriverState *bs, int64_t offset,
+                            int64_t bytes, MapEntry *e)
 {
-    int64_t ret;
+    int ret;
     int depth;
     BlockDriverState *file;
     bool has_offset;
+    int64_t map;
 
     /* As an optimization, we could cache the current range of unallocated
      * clusters in each file of the chain, and avoid querying the same
@@ -2688,12 +2672,11 @@ static int get_block_status(BlockDriverState *bs, int64_t sector_num,
 
     depth = 0;
     for (;;) {
-        ret = bdrv_get_block_status(bs, sector_num, nb_sectors, &nb_sectors,
-                                    &file);
+        ret = bdrv_block_status(bs, offset, bytes, &bytes, &map, &file);
         if (ret < 0) {
             return ret;
         }
-        assert(nb_sectors);
+        assert(bytes);
         if (ret & (BDRV_BLOCK_ZERO|BDRV_BLOCK_DATA)) {
             break;
         }
@@ -2709,11 +2692,11 @@ static int get_block_status(BlockDriverState *bs, int64_t sector_num,
     has_offset = !!(ret & BDRV_BLOCK_OFFSET_VALID);
 
     *e = (MapEntry) {
-        .start = sector_num * BDRV_SECTOR_SIZE,
-        .length = nb_sectors * BDRV_SECTOR_SIZE,
+        .start = offset,
+        .length = bytes,
         .data = !!(ret & BDRV_BLOCK_DATA),
         .zero = !!(ret & BDRV_BLOCK_ZERO),
-        .offset = ret & BDRV_BLOCK_OFFSET_MASK,
+        .offset = map,
         .has_offset = has_offset,
         .depth = depth,
         .has_filename = file && has_offset,
@@ -2839,16 +2822,12 @@ static int img_map(int argc, char **argv)
 
     length = blk_getlength(blk);
     while (curr.start + curr.length < length) {
-        int64_t nsectors_left;
-        int64_t sector_num;
-        int n;
-
-        sector_num = (curr.start + curr.length) >> BDRV_SECTOR_BITS;
+        int64_t offset = curr.start + curr.length;
+        int64_t n;
 
         /* Probe up to 1 GiB at a time.  */
-        nsectors_left = DIV_ROUND_UP(length, BDRV_SECTOR_SIZE) - sector_num;
-        n = MIN(1 << (30 - BDRV_SECTOR_BITS), nsectors_left);
-        ret = get_block_status(bs, sector_num, n, &next);
+        n = QEMU_ALIGN_DOWN(MIN(1 << 30, length - offset), BDRV_SECTOR_SIZE);
+        ret = get_block_status(bs, offset, n, &next);
 
         if (ret < 0) {
             error_report("Could not read file metadata: %s", strerror(-ret));
@@ -3241,70 +3220,58 @@ static int img_rebase(int argc, char **argv)
      * the image is the same as the original one at any time.
      */
     if (!unsafe) {
-        int64_t num_sectors;
-        int64_t old_backing_num_sectors;
-        int64_t new_backing_num_sectors = 0;
-        uint64_t sector;
-        int n;
-        int64_t count;
+        int64_t size;
+        int64_t old_backing_size;
+        int64_t new_backing_size = 0;
+        uint64_t offset;
+        int64_t n;
         float local_progress = 0;
 
         buf_old = blk_blockalign(blk, IO_BUF_SIZE);
         buf_new = blk_blockalign(blk, IO_BUF_SIZE);
 
-        num_sectors = blk_nb_sectors(blk);
-        if (num_sectors < 0) {
+        size = blk_getlength(blk);
+        if (size < 0) {
             error_report("Could not get size of '%s': %s",
-                         filename, strerror(-num_sectors));
+                         filename, strerror(-size));
             ret = -1;
             goto out;
         }
-        old_backing_num_sectors = blk_nb_sectors(blk_old_backing);
-        if (old_backing_num_sectors < 0) {
+        old_backing_size = blk_getlength(blk_old_backing);
+        if (old_backing_size < 0) {
             char backing_name[PATH_MAX];
 
             bdrv_get_backing_filename(bs, backing_name, sizeof(backing_name));
             error_report("Could not get size of '%s': %s",
-                         backing_name, strerror(-old_backing_num_sectors));
+                         backing_name, strerror(-old_backing_size));
             ret = -1;
             goto out;
         }
         if (blk_new_backing) {
-            new_backing_num_sectors = blk_nb_sectors(blk_new_backing);
-            if (new_backing_num_sectors < 0) {
+            new_backing_size = blk_getlength(blk_new_backing);
+            if (new_backing_size < 0) {
                 error_report("Could not get size of '%s': %s",
-                             out_baseimg, strerror(-new_backing_num_sectors));
+                             out_baseimg, strerror(-new_backing_size));
                 ret = -1;
                 goto out;
             }
         }
 
-        if (num_sectors != 0) {
-            local_progress = (float)100 /
-                (num_sectors / MIN(num_sectors, IO_BUF_SIZE / 512));
+        if (size != 0) {
+            local_progress = (float)100 / (size / MIN(size, IO_BUF_SIZE));
         }
 
-        for (sector = 0; sector < num_sectors; sector += n) {
-
-            /* How many sectors can we handle with the next read? */
-            if (sector + (IO_BUF_SIZE / 512) <= num_sectors) {
-                n = (IO_BUF_SIZE / 512);
-            } else {
-                n = num_sectors - sector;
-            }
+        for (offset = 0; offset < size; offset += n) {
+            /* How many bytes can we handle with the next read? */
+            n = MIN(IO_BUF_SIZE, size - offset);
 
             /* If the cluster is allocated, we don't need to take action */
-            ret = bdrv_is_allocated(bs, sector << BDRV_SECTOR_BITS,
-                                    n << BDRV_SECTOR_BITS, &count);
+            ret = bdrv_is_allocated(bs, offset, n, &n);
             if (ret < 0) {
                 error_report("error while reading image metadata: %s",
                              strerror(-ret));
                 goto out;
             }
-            /* TODO relax this once bdrv_is_allocated does not enforce
-             * sector alignment */
-            assert(QEMU_IS_ALIGNED(count, BDRV_SECTOR_SIZE));
-            n = count >> BDRV_SECTOR_BITS;
             if (ret) {
                 continue;
             }
@@ -3313,30 +3280,28 @@ static int img_rebase(int argc, char **argv)
              * Read old and new backing file and take into consideration that
              * backing files may be smaller than the COW image.
              */
-            if (sector >= old_backing_num_sectors) {
-                memset(buf_old, 0, n * BDRV_SECTOR_SIZE);
+            if (offset >= old_backing_size) {
+                memset(buf_old, 0, n);
             } else {
-                if (sector + n > old_backing_num_sectors) {
-                    n = old_backing_num_sectors - sector;
+                if (offset + n > old_backing_size) {
+                    n = old_backing_size - offset;
                 }
 
-                ret = blk_pread(blk_old_backing, sector << BDRV_SECTOR_BITS,
-                                buf_old, n << BDRV_SECTOR_BITS);
+                ret = blk_pread(blk_old_backing, offset, buf_old, n);
                 if (ret < 0) {
                     error_report("error while reading from old backing file");
                     goto out;
                 }
             }
 
-            if (sector >= new_backing_num_sectors || !blk_new_backing) {
-                memset(buf_new, 0, n * BDRV_SECTOR_SIZE);
+            if (offset >= new_backing_size || !blk_new_backing) {
+                memset(buf_new, 0, n);
             } else {
-                if (sector + n > new_backing_num_sectors) {
-                    n = new_backing_num_sectors - sector;
+                if (offset + n > new_backing_size) {
+                    n = new_backing_size - offset;
                 }
 
-                ret = blk_pread(blk_new_backing, sector << BDRV_SECTOR_BITS,
-                                buf_new, n << BDRV_SECTOR_BITS);
+                ret = blk_pread(blk_new_backing, offset, buf_new, n);
                 if (ret < 0) {
                     error_report("error while reading from new backing file");
                     goto out;
@@ -3347,15 +3312,13 @@ static int img_rebase(int argc, char **argv)
             uint64_t written = 0;
 
             while (written < n) {
-                int pnum;
+                int64_t pnum;
 
-                if (compare_sectors(buf_old + written * 512,
-                    buf_new + written * 512, n - written, &pnum))
+                if (compare_buffers(buf_old + written, buf_new + written,
+                                    n - written, &pnum))
                 {
-                    ret = blk_pwrite(blk,
-                                     (sector + written) << BDRV_SECTOR_BITS,
-                                     buf_old + written * 512,
-                                     pnum << BDRV_SECTOR_BITS, 0);
+                    ret = blk_pwrite(blk, offset + written,
+                                     buf_old + written, pnum, 0);
                     if (ret < 0) {
                         error_report("Error while writing to COW image: %s",
                             strerror(-ret));
diff --git a/qemu-img.texi b/qemu-img.texi
index ee5c5940d3..fdcf120f36 100644
--- a/qemu-img.texi
+++ b/qemu-img.texi
@@ -274,11 +274,10 @@ If the backing chain of the given image file @var{filename} has more than one
 layer, the backing file into which the changes will be committed may be
 specified as @var{base} (which has to be part of @var{filename}'s backing
 chain). If @var{base} is not specified, the immediate backing file of the top
-image (which is @var{filename}) will be used. For reasons of consistency,
-explicitly specifying @var{base} will always imply @code{-d} (since emptying an
-image after committing to an indirect backing file would lead to different data
-being read from the image due to content in the intermediate backing chain
-overruling the commit target).
+image (which is @var{filename}) will be used. Note that after a commit operation
+all images between @var{base} and the top image will be invalid and may return
+garbage data when read. For this reason, @code{-b} implies @code{-d} (so that
+the top image stays valid).
 
 @item compare [-f @var{fmt}] [-F @var{fmt}] [-T @var{src_cache}] [-p] [-s] [-q] @var{filename1} @var{filename2}
 
diff --git a/qemu-io-cmds.c b/qemu-io-cmds.c
index 3727fb43f3..de8e3de726 100644
--- a/qemu-io-cmds.c
+++ b/qemu-io-cmds.c
@@ -1769,10 +1769,6 @@ static int alloc_f(BlockBackend *blk, int argc, char **argv)
     if (offset < 0) {
         print_cvtnum_err(offset, argv[1]);
         return 0;
-    } else if (!QEMU_IS_ALIGNED(offset, BDRV_SECTOR_SIZE)) {
-        printf("%" PRId64 " is not a sector-aligned value for 'offset'\n",
-               offset);
-        return 0;
     }
 
     if (argc == 3) {
@@ -1780,19 +1776,10 @@ static int alloc_f(BlockBackend *blk, int argc, char **argv)
         if (count < 0) {
             print_cvtnum_err(count, argv[2]);
             return 0;
-        } else if (count > INT_MAX * BDRV_SECTOR_SIZE) {
-            printf("length argument cannot exceed %llu, given %s\n",
-                   INT_MAX * BDRV_SECTOR_SIZE, argv[2]);
-            return 0;
         }
     } else {
         count = BDRV_SECTOR_SIZE;
     }
-    if (!QEMU_IS_ALIGNED(count, BDRV_SECTOR_SIZE)) {
-        printf("%" PRId64 " is not a sector-aligned value for 'count'\n",
-               count);
-        return 0;
-    }
 
     remaining = count;
     sum_alloc = 0;
diff --git a/tests/qemu-iotests/067 b/tests/qemu-iotests/067
index ee9595f0da..9d561ef786 100755
--- a/tests/qemu-iotests/067
+++ b/tests/qemu-iotests/067
@@ -56,7 +56,7 @@ _filter_qmp_events()
 function run_qemu()
 {
     do_run_qemu "$@" 2>&1 | _filter_testdir | _filter_qmp | _filter_qemu \
-                          | sed -e 's/\("actual-size":\s*\)[0-9]\+/\1SIZE/g' \
+                          | _filter_actual_image_size \
                           | _filter_generated_node_ids | _filter_qmp_events
 }
 
diff --git a/tests/qemu-iotests/074.out b/tests/qemu-iotests/074.out
index 8fba5aea9c..ede66c3f81 100644
--- a/tests/qemu-iotests/074.out
+++ b/tests/qemu-iotests/074.out
@@ -4,7 +4,6 @@ Formatting 'TEST_DIR/t.IMGFMT', fmt=IMGFMT size=1073741824
 wrote 512/512 bytes at offset 512
 512 bytes, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
 qemu-img: Error while reading offset 0 of blkdebug:TEST_DIR/blkdebug.conf:TEST_DIR/t.IMGFMT: Input/output error
-qemu-img: Error while reading offset 0: Input/output error
 4
 Formatting 'TEST_DIR/t.IMGFMT', fmt=IMGFMT size=1073741824
 Formatting 'TEST_DIR/t.IMGFMT.2', fmt=IMGFMT size=0
@@ -12,7 +11,6 @@ Formatting 'TEST_DIR/t.IMGFMT.2', fmt=IMGFMT size=0
 wrote 512/512 bytes at offset 512
 512 bytes, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
 qemu-img: Error while reading offset 0 of blkdebug:TEST_DIR/blkdebug.conf:TEST_DIR/t.IMGFMT: Input/output error
-qemu-img: Error while reading offset 0 of blkdebug:TEST_DIR/blkdebug.conf:TEST_DIR/t.IMGFMT: Input/output error
 Warning: Image size mismatch!
 4
 Cleanup
diff --git a/tests/qemu-iotests/087 b/tests/qemu-iotests/087
index f8e4903f4f..27ab6c5151 100755
--- a/tests/qemu-iotests/087
+++ b/tests/qemu-iotests/087
@@ -46,7 +46,7 @@ function run_qemu()
 {
     do_run_qemu "$@" 2>&1 | _filter_testdir | _filter_qmp \
                           | _filter_qemu | _filter_imgfmt \
-                          | sed -e 's/\("actual-size":\s*\)[0-9]\+/\1SIZE/g'
+                          | _filter_actual_image_size
 }
 
 size=128M
diff --git a/tests/qemu-iotests/125 b/tests/qemu-iotests/125
index 9424313e82..c20c71570c 100755
--- a/tests/qemu-iotests/125
+++ b/tests/qemu-iotests/125
@@ -69,13 +69,15 @@ fi
 # in B
 CREATION_SIZE=$((2 * 1024 * 1024 - 48 * 1024))
 
+# 512 is the actual test -- but it's good to test 64k as well, just to be sure.
+for cluster_size in 512 64k; do
 # in kB
 for GROWTH_SIZE in 16 48 80; do
     for create_mode in off metadata falloc full; do
         for growth_mode in off metadata falloc full; do
-            echo "--- growth_size=$GROWTH_SIZE create_mode=$create_mode growth_mode=$growth_mode ---"
+            echo "--- cluster_size=$cluster_size growth_size=$GROWTH_SIZE create_mode=$create_mode growth_mode=$growth_mode ---"
 
-            IMGOPTS="preallocation=$create_mode,cluster_size=512" _make_test_img ${CREATION_SIZE}
+            IMGOPTS="preallocation=$create_mode,cluster_size=$cluster_size" _make_test_img ${CREATION_SIZE}
             $QEMU_IMG resize -f "$IMGFMT" --preallocation=$growth_mode "$TEST_IMG" +${GROWTH_SIZE}K
 
             host_size_0=$(get_image_size_on_host)
@@ -123,6 +125,7 @@ for GROWTH_SIZE in 16 48 80; do
         done
     done
 done
+done
 
 # success, all done
 echo '*** done'
diff --git a/tests/qemu-iotests/125.out b/tests/qemu-iotests/125.out
index 3f4d6e31a6..596905f533 100644
--- a/tests/qemu-iotests/125.out
+++ b/tests/qemu-iotests/125.out
@@ -1,5 +1,5 @@
 QA output created by 125
---- growth_size=16 create_mode=off growth_mode=off ---
+--- cluster_size=512 growth_size=16 create_mode=off growth_mode=off ---
 Formatting 'TEST_DIR/t.IMGFMT', fmt=IMGFMT size=2048000 preallocation=off
 Image resized.
 wrote 2048000/2048000 bytes at offset 0
@@ -7,7 +7,7 @@ wrote 2048000/2048000 bytes at offset 0
 wrote 16384/16384 bytes at offset 2048000
 16 KiB, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
 
---- growth_size=16 create_mode=off growth_mode=metadata ---
+--- cluster_size=512 growth_size=16 create_mode=off growth_mode=metadata ---
 Formatting 'TEST_DIR/t.IMGFMT', fmt=IMGFMT size=2048000 preallocation=off
 Image resized.
 wrote 2048000/2048000 bytes at offset 0
@@ -15,7 +15,7 @@ wrote 2048000/2048000 bytes at offset 0
 wrote 16384/16384 bytes at offset 2048000
 16 KiB, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
 
---- growth_size=16 create_mode=off growth_mode=falloc ---
+--- cluster_size=512 growth_size=16 create_mode=off growth_mode=falloc ---
 Formatting 'TEST_DIR/t.IMGFMT', fmt=IMGFMT size=2048000 preallocation=off
 Image resized.
 wrote 2048000/2048000 bytes at offset 0
@@ -23,7 +23,7 @@ wrote 2048000/2048000 bytes at offset 0
 wrote 16384/16384 bytes at offset 2048000
 16 KiB, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
 
---- growth_size=16 create_mode=off growth_mode=full ---
+--- cluster_size=512 growth_size=16 create_mode=off growth_mode=full ---
 Formatting 'TEST_DIR/t.IMGFMT', fmt=IMGFMT size=2048000 preallocation=off
 Image resized.
 wrote 2048000/2048000 bytes at offset 0
@@ -31,7 +31,7 @@ wrote 2048000/2048000 bytes at offset 0
 wrote 16384/16384 bytes at offset 2048000
 16 KiB, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
 
---- growth_size=16 create_mode=metadata growth_mode=off ---
+--- cluster_size=512 growth_size=16 create_mode=metadata growth_mode=off ---
 Formatting 'TEST_DIR/t.IMGFMT', fmt=IMGFMT size=2048000 preallocation=metadata
 Image resized.
 wrote 2048000/2048000 bytes at offset 0
@@ -39,7 +39,7 @@ wrote 2048000/2048000 bytes at offset 0
 wrote 16384/16384 bytes at offset 2048000
 16 KiB, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
 
---- growth_size=16 create_mode=metadata growth_mode=metadata ---
+--- cluster_size=512 growth_size=16 create_mode=metadata growth_mode=metadata ---
 Formatting 'TEST_DIR/t.IMGFMT', fmt=IMGFMT size=2048000 preallocation=metadata
 Image resized.
 wrote 2048000/2048000 bytes at offset 0
@@ -47,7 +47,7 @@ wrote 2048000/2048000 bytes at offset 0
 wrote 16384/16384 bytes at offset 2048000
 16 KiB, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
 
---- growth_size=16 create_mode=metadata growth_mode=falloc ---
+--- cluster_size=512 growth_size=16 create_mode=metadata growth_mode=falloc ---
 Formatting 'TEST_DIR/t.IMGFMT', fmt=IMGFMT size=2048000 preallocation=metadata
 Image resized.
 wrote 2048000/2048000 bytes at offset 0
@@ -55,7 +55,7 @@ wrote 2048000/2048000 bytes at offset 0
 wrote 16384/16384 bytes at offset 2048000
 16 KiB, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
 
---- growth_size=16 create_mode=metadata growth_mode=full ---
+--- cluster_size=512 growth_size=16 create_mode=metadata growth_mode=full ---
 Formatting 'TEST_DIR/t.IMGFMT', fmt=IMGFMT size=2048000 preallocation=metadata
 Image resized.
 wrote 2048000/2048000 bytes at offset 0
@@ -63,7 +63,7 @@ wrote 2048000/2048000 bytes at offset 0
 wrote 16384/16384 bytes at offset 2048000
 16 KiB, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
 
---- growth_size=16 create_mode=falloc growth_mode=off ---
+--- cluster_size=512 growth_size=16 create_mode=falloc growth_mode=off ---
 Formatting 'TEST_DIR/t.IMGFMT', fmt=IMGFMT size=2048000 preallocation=falloc
 Image resized.
 wrote 2048000/2048000 bytes at offset 0
@@ -71,7 +71,7 @@ wrote 2048000/2048000 bytes at offset 0
 wrote 16384/16384 bytes at offset 2048000
 16 KiB, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
 
---- growth_size=16 create_mode=falloc growth_mode=metadata ---
+--- cluster_size=512 growth_size=16 create_mode=falloc growth_mode=metadata ---
 Formatting 'TEST_DIR/t.IMGFMT', fmt=IMGFMT size=2048000 preallocation=falloc
 Image resized.
 wrote 2048000/2048000 bytes at offset 0
@@ -79,7 +79,7 @@ wrote 2048000/2048000 bytes at offset 0
 wrote 16384/16384 bytes at offset 2048000
 16 KiB, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
 
---- growth_size=16 create_mode=falloc growth_mode=falloc ---
+--- cluster_size=512 growth_size=16 create_mode=falloc growth_mode=falloc ---
 Formatting 'TEST_DIR/t.IMGFMT', fmt=IMGFMT size=2048000 preallocation=falloc
 Image resized.
 wrote 2048000/2048000 bytes at offset 0
@@ -87,7 +87,7 @@ wrote 2048000/2048000 bytes at offset 0
 wrote 16384/16384 bytes at offset 2048000
 16 KiB, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
 
---- growth_size=16 create_mode=falloc growth_mode=full ---
+--- cluster_size=512 growth_size=16 create_mode=falloc growth_mode=full ---
 Formatting 'TEST_DIR/t.IMGFMT', fmt=IMGFMT size=2048000 preallocation=falloc
 Image resized.
 wrote 2048000/2048000 bytes at offset 0
@@ -95,7 +95,7 @@ wrote 2048000/2048000 bytes at offset 0
 wrote 16384/16384 bytes at offset 2048000
 16 KiB, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
 
---- growth_size=16 create_mode=full growth_mode=off ---
+--- cluster_size=512 growth_size=16 create_mode=full growth_mode=off ---
 Formatting 'TEST_DIR/t.IMGFMT', fmt=IMGFMT size=2048000 preallocation=full
 Image resized.
 wrote 2048000/2048000 bytes at offset 0
@@ -103,7 +103,7 @@ wrote 2048000/2048000 bytes at offset 0
 wrote 16384/16384 bytes at offset 2048000
 16 KiB, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
 
---- growth_size=16 create_mode=full growth_mode=metadata ---
+--- cluster_size=512 growth_size=16 create_mode=full growth_mode=metadata ---
 Formatting 'TEST_DIR/t.IMGFMT', fmt=IMGFMT size=2048000 preallocation=full
 Image resized.
 wrote 2048000/2048000 bytes at offset 0
@@ -111,7 +111,7 @@ wrote 2048000/2048000 bytes at offset 0
 wrote 16384/16384 bytes at offset 2048000
 16 KiB, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
 
---- growth_size=16 create_mode=full growth_mode=falloc ---
+--- cluster_size=512 growth_size=16 create_mode=full growth_mode=falloc ---
 Formatting 'TEST_DIR/t.IMGFMT', fmt=IMGFMT size=2048000 preallocation=full
 Image resized.
 wrote 2048000/2048000 bytes at offset 0
@@ -119,7 +119,7 @@ wrote 2048000/2048000 bytes at offset 0
 wrote 16384/16384 bytes at offset 2048000
 16 KiB, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
 
---- growth_size=16 create_mode=full growth_mode=full ---
+--- cluster_size=512 growth_size=16 create_mode=full growth_mode=full ---
 Formatting 'TEST_DIR/t.IMGFMT', fmt=IMGFMT size=2048000 preallocation=full
 Image resized.
 wrote 2048000/2048000 bytes at offset 0
@@ -127,7 +127,7 @@ wrote 2048000/2048000 bytes at offset 0
 wrote 16384/16384 bytes at offset 2048000
 16 KiB, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
 
---- growth_size=48 create_mode=off growth_mode=off ---
+--- cluster_size=512 growth_size=48 create_mode=off growth_mode=off ---
 Formatting 'TEST_DIR/t.IMGFMT', fmt=IMGFMT size=2048000 preallocation=off
 Image resized.
 wrote 2048000/2048000 bytes at offset 0
@@ -135,7 +135,7 @@ wrote 2048000/2048000 bytes at offset 0
 wrote 49152/49152 bytes at offset 2048000
 48 KiB, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
 
---- growth_size=48 create_mode=off growth_mode=metadata ---
+--- cluster_size=512 growth_size=48 create_mode=off growth_mode=metadata ---
 Formatting 'TEST_DIR/t.IMGFMT', fmt=IMGFMT size=2048000 preallocation=off
 Image resized.
 wrote 2048000/2048000 bytes at offset 0
@@ -143,7 +143,7 @@ wrote 2048000/2048000 bytes at offset 0
 wrote 49152/49152 bytes at offset 2048000
 48 KiB, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
 
---- growth_size=48 create_mode=off growth_mode=falloc ---
+--- cluster_size=512 growth_size=48 create_mode=off growth_mode=falloc ---
 Formatting 'TEST_DIR/t.IMGFMT', fmt=IMGFMT size=2048000 preallocation=off
 Image resized.
 wrote 2048000/2048000 bytes at offset 0
@@ -151,7 +151,7 @@ wrote 2048000/2048000 bytes at offset 0
 wrote 49152/49152 bytes at offset 2048000
 48 KiB, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
 
---- growth_size=48 create_mode=off growth_mode=full ---
+--- cluster_size=512 growth_size=48 create_mode=off growth_mode=full ---
 Formatting 'TEST_DIR/t.IMGFMT', fmt=IMGFMT size=2048000 preallocation=off
 Image resized.
 wrote 2048000/2048000 bytes at offset 0
@@ -159,7 +159,7 @@ wrote 2048000/2048000 bytes at offset 0
 wrote 49152/49152 bytes at offset 2048000
 48 KiB, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
 
---- growth_size=48 create_mode=metadata growth_mode=off ---
+--- cluster_size=512 growth_size=48 create_mode=metadata growth_mode=off ---
 Formatting 'TEST_DIR/t.IMGFMT', fmt=IMGFMT size=2048000 preallocation=metadata
 Image resized.
 wrote 2048000/2048000 bytes at offset 0
@@ -167,7 +167,7 @@ wrote 2048000/2048000 bytes at offset 0
 wrote 49152/49152 bytes at offset 2048000
 48 KiB, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
 
---- growth_size=48 create_mode=metadata growth_mode=metadata ---
+--- cluster_size=512 growth_size=48 create_mode=metadata growth_mode=metadata ---
 Formatting 'TEST_DIR/t.IMGFMT', fmt=IMGFMT size=2048000 preallocation=metadata
 Image resized.
 wrote 2048000/2048000 bytes at offset 0
@@ -175,7 +175,7 @@ wrote 2048000/2048000 bytes at offset 0
 wrote 49152/49152 bytes at offset 2048000
 48 KiB, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
 
---- growth_size=48 create_mode=metadata growth_mode=falloc ---
+--- cluster_size=512 growth_size=48 create_mode=metadata growth_mode=falloc ---
 Formatting 'TEST_DIR/t.IMGFMT', fmt=IMGFMT size=2048000 preallocation=metadata
 Image resized.
 wrote 2048000/2048000 bytes at offset 0
@@ -183,7 +183,7 @@ wrote 2048000/2048000 bytes at offset 0
 wrote 49152/49152 bytes at offset 2048000
 48 KiB, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
 
---- growth_size=48 create_mode=metadata growth_mode=full ---
+--- cluster_size=512 growth_size=48 create_mode=metadata growth_mode=full ---
 Formatting 'TEST_DIR/t.IMGFMT', fmt=IMGFMT size=2048000 preallocation=metadata
 Image resized.
 wrote 2048000/2048000 bytes at offset 0
@@ -191,7 +191,7 @@ wrote 2048000/2048000 bytes at offset 0
 wrote 49152/49152 bytes at offset 2048000
 48 KiB, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
 
---- growth_size=48 create_mode=falloc growth_mode=off ---
+--- cluster_size=512 growth_size=48 create_mode=falloc growth_mode=off ---
 Formatting 'TEST_DIR/t.IMGFMT', fmt=IMGFMT size=2048000 preallocation=falloc
 Image resized.
 wrote 2048000/2048000 bytes at offset 0
@@ -199,7 +199,7 @@ wrote 2048000/2048000 bytes at offset 0
 wrote 49152/49152 bytes at offset 2048000
 48 KiB, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
 
---- growth_size=48 create_mode=falloc growth_mode=metadata ---
+--- cluster_size=512 growth_size=48 create_mode=falloc growth_mode=metadata ---
 Formatting 'TEST_DIR/t.IMGFMT', fmt=IMGFMT size=2048000 preallocation=falloc
 Image resized.
 wrote 2048000/2048000 bytes at offset 0
@@ -207,7 +207,7 @@ wrote 2048000/2048000 bytes at offset 0
 wrote 49152/49152 bytes at offset 2048000
 48 KiB, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
 
---- growth_size=48 create_mode=falloc growth_mode=falloc ---
+--- cluster_size=512 growth_size=48 create_mode=falloc growth_mode=falloc ---
 Formatting 'TEST_DIR/t.IMGFMT', fmt=IMGFMT size=2048000 preallocation=falloc
 Image resized.
 wrote 2048000/2048000 bytes at offset 0
@@ -215,7 +215,7 @@ wrote 2048000/2048000 bytes at offset 0
 wrote 49152/49152 bytes at offset 2048000
 48 KiB, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
 
---- growth_size=48 create_mode=falloc growth_mode=full ---
+--- cluster_size=512 growth_size=48 create_mode=falloc growth_mode=full ---
 Formatting 'TEST_DIR/t.IMGFMT', fmt=IMGFMT size=2048000 preallocation=falloc
 Image resized.
 wrote 2048000/2048000 bytes at offset 0
@@ -223,7 +223,7 @@ wrote 2048000/2048000 bytes at offset 0
 wrote 49152/49152 bytes at offset 2048000
 48 KiB, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
 
---- growth_size=48 create_mode=full growth_mode=off ---
+--- cluster_size=512 growth_size=48 create_mode=full growth_mode=off ---
 Formatting 'TEST_DIR/t.IMGFMT', fmt=IMGFMT size=2048000 preallocation=full
 Image resized.
 wrote 2048000/2048000 bytes at offset 0
@@ -231,7 +231,7 @@ wrote 2048000/2048000 bytes at offset 0
 wrote 49152/49152 bytes at offset 2048000
 48 KiB, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
 
---- growth_size=48 create_mode=full growth_mode=metadata ---
+--- cluster_size=512 growth_size=48 create_mode=full growth_mode=metadata ---
 Formatting 'TEST_DIR/t.IMGFMT', fmt=IMGFMT size=2048000 preallocation=full
 Image resized.
 wrote 2048000/2048000 bytes at offset 0
@@ -239,7 +239,7 @@ wrote 2048000/2048000 bytes at offset 0
 wrote 49152/49152 bytes at offset 2048000
 48 KiB, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
 
---- growth_size=48 create_mode=full growth_mode=falloc ---
+--- cluster_size=512 growth_size=48 create_mode=full growth_mode=falloc ---
 Formatting 'TEST_DIR/t.IMGFMT', fmt=IMGFMT size=2048000 preallocation=full
 Image resized.
 wrote 2048000/2048000 bytes at offset 0
@@ -247,7 +247,7 @@ wrote 2048000/2048000 bytes at offset 0
 wrote 49152/49152 bytes at offset 2048000
 48 KiB, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
 
---- growth_size=48 create_mode=full growth_mode=full ---
+--- cluster_size=512 growth_size=48 create_mode=full growth_mode=full ---
 Formatting 'TEST_DIR/t.IMGFMT', fmt=IMGFMT size=2048000 preallocation=full
 Image resized.
 wrote 2048000/2048000 bytes at offset 0
@@ -255,7 +255,7 @@ wrote 2048000/2048000 bytes at offset 0
 wrote 49152/49152 bytes at offset 2048000
 48 KiB, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
 
---- growth_size=80 create_mode=off growth_mode=off ---
+--- cluster_size=512 growth_size=80 create_mode=off growth_mode=off ---
 Formatting 'TEST_DIR/t.IMGFMT', fmt=IMGFMT size=2048000 preallocation=off
 Image resized.
 wrote 2048000/2048000 bytes at offset 0
@@ -263,7 +263,7 @@ wrote 2048000/2048000 bytes at offset 0
 wrote 81920/81920 bytes at offset 2048000
 80 KiB, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
 
---- growth_size=80 create_mode=off growth_mode=metadata ---
+--- cluster_size=512 growth_size=80 create_mode=off growth_mode=metadata ---
 Formatting 'TEST_DIR/t.IMGFMT', fmt=IMGFMT size=2048000 preallocation=off
 Image resized.
 wrote 2048000/2048000 bytes at offset 0
@@ -271,7 +271,7 @@ wrote 2048000/2048000 bytes at offset 0
 wrote 81920/81920 bytes at offset 2048000
 80 KiB, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
 
---- growth_size=80 create_mode=off growth_mode=falloc ---
+--- cluster_size=512 growth_size=80 create_mode=off growth_mode=falloc ---
 Formatting 'TEST_DIR/t.IMGFMT', fmt=IMGFMT size=2048000 preallocation=off
 Image resized.
 wrote 2048000/2048000 bytes at offset 0
@@ -279,7 +279,7 @@ wrote 2048000/2048000 bytes at offset 0
 wrote 81920/81920 bytes at offset 2048000
 80 KiB, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
 
---- growth_size=80 create_mode=off growth_mode=full ---
+--- cluster_size=512 growth_size=80 create_mode=off growth_mode=full ---
 Formatting 'TEST_DIR/t.IMGFMT', fmt=IMGFMT size=2048000 preallocation=off
 Image resized.
 wrote 2048000/2048000 bytes at offset 0
@@ -287,7 +287,7 @@ wrote 2048000/2048000 bytes at offset 0
 wrote 81920/81920 bytes at offset 2048000
 80 KiB, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
 
---- growth_size=80 create_mode=metadata growth_mode=off ---
+--- cluster_size=512 growth_size=80 create_mode=metadata growth_mode=off ---
 Formatting 'TEST_DIR/t.IMGFMT', fmt=IMGFMT size=2048000 preallocation=metadata
 Image resized.
 wrote 2048000/2048000 bytes at offset 0
@@ -295,7 +295,7 @@ wrote 2048000/2048000 bytes at offset 0
 wrote 81920/81920 bytes at offset 2048000
 80 KiB, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
 
---- growth_size=80 create_mode=metadata growth_mode=metadata ---
+--- cluster_size=512 growth_size=80 create_mode=metadata growth_mode=metadata ---
 Formatting 'TEST_DIR/t.IMGFMT', fmt=IMGFMT size=2048000 preallocation=metadata
 Image resized.
 wrote 2048000/2048000 bytes at offset 0
@@ -303,7 +303,7 @@ wrote 2048000/2048000 bytes at offset 0
 wrote 81920/81920 bytes at offset 2048000
 80 KiB, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
 
---- growth_size=80 create_mode=metadata growth_mode=falloc ---
+--- cluster_size=512 growth_size=80 create_mode=metadata growth_mode=falloc ---
 Formatting 'TEST_DIR/t.IMGFMT', fmt=IMGFMT size=2048000 preallocation=metadata
 Image resized.
 wrote 2048000/2048000 bytes at offset 0
@@ -311,7 +311,7 @@ wrote 2048000/2048000 bytes at offset 0
 wrote 81920/81920 bytes at offset 2048000
 80 KiB, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
 
---- growth_size=80 create_mode=metadata growth_mode=full ---
+--- cluster_size=512 growth_size=80 create_mode=metadata growth_mode=full ---
 Formatting 'TEST_DIR/t.IMGFMT', fmt=IMGFMT size=2048000 preallocation=metadata
 Image resized.
 wrote 2048000/2048000 bytes at offset 0
@@ -319,7 +319,7 @@ wrote 2048000/2048000 bytes at offset 0
 wrote 81920/81920 bytes at offset 2048000
 80 KiB, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
 
---- growth_size=80 create_mode=falloc growth_mode=off ---
+--- cluster_size=512 growth_size=80 create_mode=falloc growth_mode=off ---
 Formatting 'TEST_DIR/t.IMGFMT', fmt=IMGFMT size=2048000 preallocation=falloc
 Image resized.
 wrote 2048000/2048000 bytes at offset 0
@@ -327,7 +327,7 @@ wrote 2048000/2048000 bytes at offset 0
 wrote 81920/81920 bytes at offset 2048000
 80 KiB, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
 
---- growth_size=80 create_mode=falloc growth_mode=metadata ---
+--- cluster_size=512 growth_size=80 create_mode=falloc growth_mode=metadata ---
 Formatting 'TEST_DIR/t.IMGFMT', fmt=IMGFMT size=2048000 preallocation=falloc
 Image resized.
 wrote 2048000/2048000 bytes at offset 0
@@ -335,7 +335,7 @@ wrote 2048000/2048000 bytes at offset 0
 wrote 81920/81920 bytes at offset 2048000
 80 KiB, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
 
---- growth_size=80 create_mode=falloc growth_mode=falloc ---
+--- cluster_size=512 growth_size=80 create_mode=falloc growth_mode=falloc ---
 Formatting 'TEST_DIR/t.IMGFMT', fmt=IMGFMT size=2048000 preallocation=falloc
 Image resized.
 wrote 2048000/2048000 bytes at offset 0
@@ -343,7 +343,7 @@ wrote 2048000/2048000 bytes at offset 0
 wrote 81920/81920 bytes at offset 2048000
 80 KiB, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
 
---- growth_size=80 create_mode=falloc growth_mode=full ---
+--- cluster_size=512 growth_size=80 create_mode=falloc growth_mode=full ---
 Formatting 'TEST_DIR/t.IMGFMT', fmt=IMGFMT size=2048000 preallocation=falloc
 Image resized.
 wrote 2048000/2048000 bytes at offset 0
@@ -351,7 +351,7 @@ wrote 2048000/2048000 bytes at offset 0
 wrote 81920/81920 bytes at offset 2048000
 80 KiB, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
 
---- growth_size=80 create_mode=full growth_mode=off ---
+--- cluster_size=512 growth_size=80 create_mode=full growth_mode=off ---
 Formatting 'TEST_DIR/t.IMGFMT', fmt=IMGFMT size=2048000 preallocation=full
 Image resized.
 wrote 2048000/2048000 bytes at offset 0
@@ -359,7 +359,7 @@ wrote 2048000/2048000 bytes at offset 0
 wrote 81920/81920 bytes at offset 2048000
 80 KiB, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
 
---- growth_size=80 create_mode=full growth_mode=metadata ---
+--- cluster_size=512 growth_size=80 create_mode=full growth_mode=metadata ---
 Formatting 'TEST_DIR/t.IMGFMT', fmt=IMGFMT size=2048000 preallocation=full
 Image resized.
 wrote 2048000/2048000 bytes at offset 0
@@ -367,7 +367,7 @@ wrote 2048000/2048000 bytes at offset 0
 wrote 81920/81920 bytes at offset 2048000
 80 KiB, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
 
---- growth_size=80 create_mode=full growth_mode=falloc ---
+--- cluster_size=512 growth_size=80 create_mode=full growth_mode=falloc ---
 Formatting 'TEST_DIR/t.IMGFMT', fmt=IMGFMT size=2048000 preallocation=full
 Image resized.
 wrote 2048000/2048000 bytes at offset 0
@@ -375,7 +375,391 @@ wrote 2048000/2048000 bytes at offset 0
 wrote 81920/81920 bytes at offset 2048000
 80 KiB, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
 
---- growth_size=80 create_mode=full growth_mode=full ---
+--- cluster_size=512 growth_size=80 create_mode=full growth_mode=full ---
+Formatting 'TEST_DIR/t.IMGFMT', fmt=IMGFMT size=2048000 preallocation=full
+Image resized.
+wrote 2048000/2048000 bytes at offset 0
+1.953 MiB, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
+wrote 81920/81920 bytes at offset 2048000
+80 KiB, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
+
+--- cluster_size=64k growth_size=16 create_mode=off growth_mode=off ---
+Formatting 'TEST_DIR/t.IMGFMT', fmt=IMGFMT size=2048000 preallocation=off
+Image resized.
+wrote 2048000/2048000 bytes at offset 0
+1.953 MiB, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
+wrote 16384/16384 bytes at offset 2048000
+16 KiB, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
+
+--- cluster_size=64k growth_size=16 create_mode=off growth_mode=metadata ---
+Formatting 'TEST_DIR/t.IMGFMT', fmt=IMGFMT size=2048000 preallocation=off
+Image resized.
+wrote 2048000/2048000 bytes at offset 0
+1.953 MiB, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
+wrote 16384/16384 bytes at offset 2048000
+16 KiB, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
+
+--- cluster_size=64k growth_size=16 create_mode=off growth_mode=falloc ---
+Formatting 'TEST_DIR/t.IMGFMT', fmt=IMGFMT size=2048000 preallocation=off
+Image resized.
+wrote 2048000/2048000 bytes at offset 0
+1.953 MiB, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
+wrote 16384/16384 bytes at offset 2048000
+16 KiB, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
+
+--- cluster_size=64k growth_size=16 create_mode=off growth_mode=full ---
+Formatting 'TEST_DIR/t.IMGFMT', fmt=IMGFMT size=2048000 preallocation=off
+Image resized.
+wrote 2048000/2048000 bytes at offset 0
+1.953 MiB, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
+wrote 16384/16384 bytes at offset 2048000
+16 KiB, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
+
+--- cluster_size=64k growth_size=16 create_mode=metadata growth_mode=off ---
+Formatting 'TEST_DIR/t.IMGFMT', fmt=IMGFMT size=2048000 preallocation=metadata
+Image resized.
+wrote 2048000/2048000 bytes at offset 0
+1.953 MiB, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
+wrote 16384/16384 bytes at offset 2048000
+16 KiB, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
+
+--- cluster_size=64k growth_size=16 create_mode=metadata growth_mode=metadata ---
+Formatting 'TEST_DIR/t.IMGFMT', fmt=IMGFMT size=2048000 preallocation=metadata
+Image resized.
+wrote 2048000/2048000 bytes at offset 0
+1.953 MiB, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
+wrote 16384/16384 bytes at offset 2048000
+16 KiB, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
+
+--- cluster_size=64k growth_size=16 create_mode=metadata growth_mode=falloc ---
+Formatting 'TEST_DIR/t.IMGFMT', fmt=IMGFMT size=2048000 preallocation=metadata
+Image resized.
+wrote 2048000/2048000 bytes at offset 0
+1.953 MiB, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
+wrote 16384/16384 bytes at offset 2048000
+16 KiB, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
+
+--- cluster_size=64k growth_size=16 create_mode=metadata growth_mode=full ---
+Formatting 'TEST_DIR/t.IMGFMT', fmt=IMGFMT size=2048000 preallocation=metadata
+Image resized.
+wrote 2048000/2048000 bytes at offset 0
+1.953 MiB, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
+wrote 16384/16384 bytes at offset 2048000
+16 KiB, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
+
+--- cluster_size=64k growth_size=16 create_mode=falloc growth_mode=off ---
+Formatting 'TEST_DIR/t.IMGFMT', fmt=IMGFMT size=2048000 preallocation=falloc
+Image resized.
+wrote 2048000/2048000 bytes at offset 0
+1.953 MiB, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
+wrote 16384/16384 bytes at offset 2048000
+16 KiB, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
+
+--- cluster_size=64k growth_size=16 create_mode=falloc growth_mode=metadata ---
+Formatting 'TEST_DIR/t.IMGFMT', fmt=IMGFMT size=2048000 preallocation=falloc
+Image resized.
+wrote 2048000/2048000 bytes at offset 0
+1.953 MiB, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
+wrote 16384/16384 bytes at offset 2048000
+16 KiB, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
+
+--- cluster_size=64k growth_size=16 create_mode=falloc growth_mode=falloc ---
+Formatting 'TEST_DIR/t.IMGFMT', fmt=IMGFMT size=2048000 preallocation=falloc
+Image resized.
+wrote 2048000/2048000 bytes at offset 0
+1.953 MiB, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
+wrote 16384/16384 bytes at offset 2048000
+16 KiB, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
+
+--- cluster_size=64k growth_size=16 create_mode=falloc growth_mode=full ---
+Formatting 'TEST_DIR/t.IMGFMT', fmt=IMGFMT size=2048000 preallocation=falloc
+Image resized.
+wrote 2048000/2048000 bytes at offset 0
+1.953 MiB, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
+wrote 16384/16384 bytes at offset 2048000
+16 KiB, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
+
+--- cluster_size=64k growth_size=16 create_mode=full growth_mode=off ---
+Formatting 'TEST_DIR/t.IMGFMT', fmt=IMGFMT size=2048000 preallocation=full
+Image resized.
+wrote 2048000/2048000 bytes at offset 0
+1.953 MiB, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
+wrote 16384/16384 bytes at offset 2048000
+16 KiB, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
+
+--- cluster_size=64k growth_size=16 create_mode=full growth_mode=metadata ---
+Formatting 'TEST_DIR/t.IMGFMT', fmt=IMGFMT size=2048000 preallocation=full
+Image resized.
+wrote 2048000/2048000 bytes at offset 0
+1.953 MiB, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
+wrote 16384/16384 bytes at offset 2048000
+16 KiB, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
+
+--- cluster_size=64k growth_size=16 create_mode=full growth_mode=falloc ---
+Formatting 'TEST_DIR/t.IMGFMT', fmt=IMGFMT size=2048000 preallocation=full
+Image resized.
+wrote 2048000/2048000 bytes at offset 0
+1.953 MiB, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
+wrote 16384/16384 bytes at offset 2048000
+16 KiB, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
+
+--- cluster_size=64k growth_size=16 create_mode=full growth_mode=full ---
+Formatting 'TEST_DIR/t.IMGFMT', fmt=IMGFMT size=2048000 preallocation=full
+Image resized.
+wrote 2048000/2048000 bytes at offset 0
+1.953 MiB, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
+wrote 16384/16384 bytes at offset 2048000
+16 KiB, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
+
+--- cluster_size=64k growth_size=48 create_mode=off growth_mode=off ---
+Formatting 'TEST_DIR/t.IMGFMT', fmt=IMGFMT size=2048000 preallocation=off
+Image resized.
+wrote 2048000/2048000 bytes at offset 0
+1.953 MiB, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
+wrote 49152/49152 bytes at offset 2048000
+48 KiB, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
+
+--- cluster_size=64k growth_size=48 create_mode=off growth_mode=metadata ---
+Formatting 'TEST_DIR/t.IMGFMT', fmt=IMGFMT size=2048000 preallocation=off
+Image resized.
+wrote 2048000/2048000 bytes at offset 0
+1.953 MiB, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
+wrote 49152/49152 bytes at offset 2048000
+48 KiB, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
+
+--- cluster_size=64k growth_size=48 create_mode=off growth_mode=falloc ---
+Formatting 'TEST_DIR/t.IMGFMT', fmt=IMGFMT size=2048000 preallocation=off
+Image resized.
+wrote 2048000/2048000 bytes at offset 0
+1.953 MiB, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
+wrote 49152/49152 bytes at offset 2048000
+48 KiB, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
+
+--- cluster_size=64k growth_size=48 create_mode=off growth_mode=full ---
+Formatting 'TEST_DIR/t.IMGFMT', fmt=IMGFMT size=2048000 preallocation=off
+Image resized.
+wrote 2048000/2048000 bytes at offset 0
+1.953 MiB, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
+wrote 49152/49152 bytes at offset 2048000
+48 KiB, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
+
+--- cluster_size=64k growth_size=48 create_mode=metadata growth_mode=off ---
+Formatting 'TEST_DIR/t.IMGFMT', fmt=IMGFMT size=2048000 preallocation=metadata
+Image resized.
+wrote 2048000/2048000 bytes at offset 0
+1.953 MiB, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
+wrote 49152/49152 bytes at offset 2048000
+48 KiB, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
+
+--- cluster_size=64k growth_size=48 create_mode=metadata growth_mode=metadata ---
+Formatting 'TEST_DIR/t.IMGFMT', fmt=IMGFMT size=2048000 preallocation=metadata
+Image resized.
+wrote 2048000/2048000 bytes at offset 0
+1.953 MiB, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
+wrote 49152/49152 bytes at offset 2048000
+48 KiB, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
+
+--- cluster_size=64k growth_size=48 create_mode=metadata growth_mode=falloc ---
+Formatting 'TEST_DIR/t.IMGFMT', fmt=IMGFMT size=2048000 preallocation=metadata
+Image resized.
+wrote 2048000/2048000 bytes at offset 0
+1.953 MiB, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
+wrote 49152/49152 bytes at offset 2048000
+48 KiB, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
+
+--- cluster_size=64k growth_size=48 create_mode=metadata growth_mode=full ---
+Formatting 'TEST_DIR/t.IMGFMT', fmt=IMGFMT size=2048000 preallocation=metadata
+Image resized.
+wrote 2048000/2048000 bytes at offset 0
+1.953 MiB, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
+wrote 49152/49152 bytes at offset 2048000
+48 KiB, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
+
+--- cluster_size=64k growth_size=48 create_mode=falloc growth_mode=off ---
+Formatting 'TEST_DIR/t.IMGFMT', fmt=IMGFMT size=2048000 preallocation=falloc
+Image resized.
+wrote 2048000/2048000 bytes at offset 0
+1.953 MiB, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
+wrote 49152/49152 bytes at offset 2048000
+48 KiB, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
+
+--- cluster_size=64k growth_size=48 create_mode=falloc growth_mode=metadata ---
+Formatting 'TEST_DIR/t.IMGFMT', fmt=IMGFMT size=2048000 preallocation=falloc
+Image resized.
+wrote 2048000/2048000 bytes at offset 0
+1.953 MiB, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
+wrote 49152/49152 bytes at offset 2048000
+48 KiB, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
+
+--- cluster_size=64k growth_size=48 create_mode=falloc growth_mode=falloc ---
+Formatting 'TEST_DIR/t.IMGFMT', fmt=IMGFMT size=2048000 preallocation=falloc
+Image resized.
+wrote 2048000/2048000 bytes at offset 0
+1.953 MiB, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
+wrote 49152/49152 bytes at offset 2048000
+48 KiB, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
+
+--- cluster_size=64k growth_size=48 create_mode=falloc growth_mode=full ---
+Formatting 'TEST_DIR/t.IMGFMT', fmt=IMGFMT size=2048000 preallocation=falloc
+Image resized.
+wrote 2048000/2048000 bytes at offset 0
+1.953 MiB, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
+wrote 49152/49152 bytes at offset 2048000
+48 KiB, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
+
+--- cluster_size=64k growth_size=48 create_mode=full growth_mode=off ---
+Formatting 'TEST_DIR/t.IMGFMT', fmt=IMGFMT size=2048000 preallocation=full
+Image resized.
+wrote 2048000/2048000 bytes at offset 0
+1.953 MiB, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
+wrote 49152/49152 bytes at offset 2048000
+48 KiB, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
+
+--- cluster_size=64k growth_size=48 create_mode=full growth_mode=metadata ---
+Formatting 'TEST_DIR/t.IMGFMT', fmt=IMGFMT size=2048000 preallocation=full
+Image resized.
+wrote 2048000/2048000 bytes at offset 0
+1.953 MiB, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
+wrote 49152/49152 bytes at offset 2048000
+48 KiB, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
+
+--- cluster_size=64k growth_size=48 create_mode=full growth_mode=falloc ---
+Formatting 'TEST_DIR/t.IMGFMT', fmt=IMGFMT size=2048000 preallocation=full
+Image resized.
+wrote 2048000/2048000 bytes at offset 0
+1.953 MiB, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
+wrote 49152/49152 bytes at offset 2048000
+48 KiB, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
+
+--- cluster_size=64k growth_size=48 create_mode=full growth_mode=full ---
+Formatting 'TEST_DIR/t.IMGFMT', fmt=IMGFMT size=2048000 preallocation=full
+Image resized.
+wrote 2048000/2048000 bytes at offset 0
+1.953 MiB, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
+wrote 49152/49152 bytes at offset 2048000
+48 KiB, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
+
+--- cluster_size=64k growth_size=80 create_mode=off growth_mode=off ---
+Formatting 'TEST_DIR/t.IMGFMT', fmt=IMGFMT size=2048000 preallocation=off
+Image resized.
+wrote 2048000/2048000 bytes at offset 0
+1.953 MiB, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
+wrote 81920/81920 bytes at offset 2048000
+80 KiB, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
+
+--- cluster_size=64k growth_size=80 create_mode=off growth_mode=metadata ---
+Formatting 'TEST_DIR/t.IMGFMT', fmt=IMGFMT size=2048000 preallocation=off
+Image resized.
+wrote 2048000/2048000 bytes at offset 0
+1.953 MiB, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
+wrote 81920/81920 bytes at offset 2048000
+80 KiB, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
+
+--- cluster_size=64k growth_size=80 create_mode=off growth_mode=falloc ---
+Formatting 'TEST_DIR/t.IMGFMT', fmt=IMGFMT size=2048000 preallocation=off
+Image resized.
+wrote 2048000/2048000 bytes at offset 0
+1.953 MiB, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
+wrote 81920/81920 bytes at offset 2048000
+80 KiB, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
+
+--- cluster_size=64k growth_size=80 create_mode=off growth_mode=full ---
+Formatting 'TEST_DIR/t.IMGFMT', fmt=IMGFMT size=2048000 preallocation=off
+Image resized.
+wrote 2048000/2048000 bytes at offset 0
+1.953 MiB, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
+wrote 81920/81920 bytes at offset 2048000
+80 KiB, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
+
+--- cluster_size=64k growth_size=80 create_mode=metadata growth_mode=off ---
+Formatting 'TEST_DIR/t.IMGFMT', fmt=IMGFMT size=2048000 preallocation=metadata
+Image resized.
+wrote 2048000/2048000 bytes at offset 0
+1.953 MiB, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
+wrote 81920/81920 bytes at offset 2048000
+80 KiB, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
+
+--- cluster_size=64k growth_size=80 create_mode=metadata growth_mode=metadata ---
+Formatting 'TEST_DIR/t.IMGFMT', fmt=IMGFMT size=2048000 preallocation=metadata
+Image resized.
+wrote 2048000/2048000 bytes at offset 0
+1.953 MiB, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
+wrote 81920/81920 bytes at offset 2048000
+80 KiB, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
+
+--- cluster_size=64k growth_size=80 create_mode=metadata growth_mode=falloc ---
+Formatting 'TEST_DIR/t.IMGFMT', fmt=IMGFMT size=2048000 preallocation=metadata
+Image resized.
+wrote 2048000/2048000 bytes at offset 0
+1.953 MiB, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
+wrote 81920/81920 bytes at offset 2048000
+80 KiB, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
+
+--- cluster_size=64k growth_size=80 create_mode=metadata growth_mode=full ---
+Formatting 'TEST_DIR/t.IMGFMT', fmt=IMGFMT size=2048000 preallocation=metadata
+Image resized.
+wrote 2048000/2048000 bytes at offset 0
+1.953 MiB, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
+wrote 81920/81920 bytes at offset 2048000
+80 KiB, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
+
+--- cluster_size=64k growth_size=80 create_mode=falloc growth_mode=off ---
+Formatting 'TEST_DIR/t.IMGFMT', fmt=IMGFMT size=2048000 preallocation=falloc
+Image resized.
+wrote 2048000/2048000 bytes at offset 0
+1.953 MiB, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
+wrote 81920/81920 bytes at offset 2048000
+80 KiB, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
+
+--- cluster_size=64k growth_size=80 create_mode=falloc growth_mode=metadata ---
+Formatting 'TEST_DIR/t.IMGFMT', fmt=IMGFMT size=2048000 preallocation=falloc
+Image resized.
+wrote 2048000/2048000 bytes at offset 0
+1.953 MiB, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
+wrote 81920/81920 bytes at offset 2048000
+80 KiB, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
+
+--- cluster_size=64k growth_size=80 create_mode=falloc growth_mode=falloc ---
+Formatting 'TEST_DIR/t.IMGFMT', fmt=IMGFMT size=2048000 preallocation=falloc
+Image resized.
+wrote 2048000/2048000 bytes at offset 0
+1.953 MiB, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
+wrote 81920/81920 bytes at offset 2048000
+80 KiB, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
+
+--- cluster_size=64k growth_size=80 create_mode=falloc growth_mode=full ---
+Formatting 'TEST_DIR/t.IMGFMT', fmt=IMGFMT size=2048000 preallocation=falloc
+Image resized.
+wrote 2048000/2048000 bytes at offset 0
+1.953 MiB, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
+wrote 81920/81920 bytes at offset 2048000
+80 KiB, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
+
+--- cluster_size=64k growth_size=80 create_mode=full growth_mode=off ---
+Formatting 'TEST_DIR/t.IMGFMT', fmt=IMGFMT size=2048000 preallocation=full
+Image resized.
+wrote 2048000/2048000 bytes at offset 0
+1.953 MiB, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
+wrote 81920/81920 bytes at offset 2048000
+80 KiB, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
+
+--- cluster_size=64k growth_size=80 create_mode=full growth_mode=metadata ---
+Formatting 'TEST_DIR/t.IMGFMT', fmt=IMGFMT size=2048000 preallocation=full
+Image resized.
+wrote 2048000/2048000 bytes at offset 0
+1.953 MiB, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
+wrote 81920/81920 bytes at offset 2048000
+80 KiB, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
+
+--- cluster_size=64k growth_size=80 create_mode=full growth_mode=falloc ---
+Formatting 'TEST_DIR/t.IMGFMT', fmt=IMGFMT size=2048000 preallocation=full
+Image resized.
+wrote 2048000/2048000 bytes at offset 0
+1.953 MiB, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
+wrote 81920/81920 bytes at offset 2048000
+80 KiB, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
+
+--- cluster_size=64k growth_size=80 create_mode=full growth_mode=full ---
 Formatting 'TEST_DIR/t.IMGFMT', fmt=IMGFMT size=2048000 preallocation=full
 Image resized.
 wrote 2048000/2048000 bytes at offset 0
diff --git a/tests/qemu-iotests/127 b/tests/qemu-iotests/127
new file mode 100755
index 0000000000..9e0d7d3be8
--- /dev/null
+++ b/tests/qemu-iotests/127
@@ -0,0 +1,97 @@
+#!/bin/bash
+#
+# Test case for mirroring with dataplane
+#
+# Copyright (C) 2017 Red Hat, Inc.
+#
+# This program is free software; you can redistribute it and/or modify
+# it under the terms of the GNU General Public License as published by
+# the Free Software Foundation; either version 2 of the License, or
+# (at your option) any later version.
+#
+# This program is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+# GNU General Public License for more details.
+#
+# You should have received a copy of the GNU General Public License
+# along with this program.  If not, see <http://www.gnu.org/licenses/>.
+#
+
+# creator
+owner=mreitz@redhat.com
+
+seq=$(basename $0)
+echo "QA output created by $seq"
+
+here=$PWD
+status=1    # failure is the default!
+
+_cleanup()
+{
+    _cleanup_qemu
+    _cleanup_test_img
+    _rm_test_img "$TEST_IMG.overlay0"
+    _rm_test_img "$TEST_IMG.overlay1"
+}
+trap "_cleanup; exit \$status" 0 1 2 3 15
+
+# get standard environment, filters and qemu instance handling
+. ./common.rc
+. ./common.filter
+. ./common.qemu
+
+_supported_fmt qcow2
+_supported_proto file
+_supported_os Linux
+
+IMG_SIZE=64K
+
+_make_test_img $IMG_SIZE
+TEST_IMG="$TEST_IMG.overlay0" _make_test_img -b "$TEST_IMG" $IMG_SIZE
+TEST_IMG="$TEST_IMG.overlay1" _make_test_img -b "$TEST_IMG" $IMG_SIZE
+
+# So that we actually have something to mirror and the job does not return
+# immediately (which may be bad because then we cannot know whether the
+# 'return' or the 'BLOCK_JOB_READY' comes first).
+$QEMU_IO -c 'write 0 42' "$TEST_IMG.overlay0" | _filter_qemu_io
+
+# We cannot use virtio-blk here because that does not actually set the attached
+# BB's AioContext in qtest mode
+_launch_qemu \
+    -object iothread,id=iothr \
+    -blockdev node-name=source,driver=$IMGFMT,file.driver=file,file.filename="$TEST_IMG.overlay0" \
+    -device virtio-scsi,id=scsi-bus,iothread=iothr \
+    -device scsi-hd,bus=scsi-bus.0,drive=source
+
+_send_qemu_cmd $QEMU_HANDLE \
+    "{ 'execute': 'qmp_capabilities' }" \
+    'return'
+
+_send_qemu_cmd $QEMU_HANDLE \
+    "{ 'execute': 'drive-mirror',
+       'arguments': {
+           'job-id': 'mirror',
+           'device': 'source',
+           'target': '$TEST_IMG.overlay1',
+           'mode':   'existing',
+           'sync':   'top'
+       } }" \
+    'BLOCK_JOB_READY'
+
+# The backing BDS should be assigned the overlay's AioContext
+_send_qemu_cmd $QEMU_HANDLE \
+    "{ 'execute': 'block-job-complete',
+       'arguments': { 'device': 'mirror' } }" \
+    'BLOCK_JOB_COMPLETED'
+
+_send_qemu_cmd $QEMU_HANDLE \
+    "{ 'execute': 'quit' }" \
+    'return'
+
+wait=yes _cleanup_qemu
+
+# success, all done
+echo '*** done'
+rm -f $seq.full
+status=0
diff --git a/tests/qemu-iotests/127.out b/tests/qemu-iotests/127.out
new file mode 100644
index 0000000000..543d075005
--- /dev/null
+++ b/tests/qemu-iotests/127.out
@@ -0,0 +1,14 @@
+QA output created by 127
+Formatting 'TEST_DIR/t.IMGFMT', fmt=IMGFMT size=65536
+Formatting 'TEST_DIR/t.IMGFMT.overlay0', fmt=IMGFMT size=65536 backing_file=TEST_DIR/t.IMGFMT
+Formatting 'TEST_DIR/t.IMGFMT.overlay1', fmt=IMGFMT size=65536 backing_file=TEST_DIR/t.IMGFMT
+wrote 42/42 bytes at offset 0
+42 bytes, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
+{"return": {}}
+{"return": {}}
+{"timestamp": {"seconds":  TIMESTAMP, "microseconds":  TIMESTAMP}, "event": "BLOCK_JOB_READY", "data": {"device": "mirror", "len": 65536, "offset": 65536, "speed": 0, "type": "mirror"}}
+{"return": {}}
+{"timestamp": {"seconds":  TIMESTAMP, "microseconds":  TIMESTAMP}, "event": "BLOCK_JOB_COMPLETED", "data": {"device": "mirror", "len": 65536, "offset": 65536, "speed": 0, "type": "mirror"}}
+{"return": {}}
+{"timestamp": {"seconds":  TIMESTAMP, "microseconds":  TIMESTAMP}, "event": "SHUTDOWN", "data": {"guest": false}}
+*** done
diff --git a/tests/qemu-iotests/177 b/tests/qemu-iotests/177
index f8ed8fb86b..28990977f1 100755
--- a/tests/qemu-iotests/177
+++ b/tests/qemu-iotests/177
@@ -51,7 +51,7 @@ echo "== setting up files =="
 TEST_IMG="$TEST_IMG.base" _make_test_img $size
 $QEMU_IO -c "write -P 11 0 $size" "$TEST_IMG.base" | _filter_qemu_io
 _make_test_img -b "$TEST_IMG.base"
-$QEMU_IO -c "write -P 22 0 $size" "$TEST_IMG" | _filter_qemu_io
+$QEMU_IO -c "write -P 22 0 110M" "$TEST_IMG" | _filter_qemu_io
 
 # Limited to 64k max-transfer
 echo
@@ -82,6 +82,13 @@ $QEMU_IO -c "open -o $options,$limits blkdebug::$TEST_IMG" \
          -c "discard 80000001 30M" | _filter_qemu_io
 
 echo
+echo "== block status smaller than alignment =="
+limits=align=4k
+$QEMU_IO -c "open -o $options,$limits blkdebug::$TEST_IMG" \
+	 -c "alloc 1 1" -c "alloc 0x6dffff0 1000" -c "alloc 127m 5P" \
+	 -c map | _filter_qemu_io
+
+echo
 echo "== verify image content =="
 
 function verify_io()
@@ -103,7 +110,8 @@ function verify_io()
     echo read -P 0 32M 32M
     echo read -P 22 64M 13M
     echo read -P $discarded 77M 29M
-    echo read -P 22 106M 22M
+    echo read -P 22 106M 4M
+    echo read -P 11 110M 18M
 }
 
 verify_io | $QEMU_IO -r "$TEST_IMG" | _filter_qemu_io
diff --git a/tests/qemu-iotests/177.out b/tests/qemu-iotests/177.out
index 43a777836c..f788b55e20 100644
--- a/tests/qemu-iotests/177.out
+++ b/tests/qemu-iotests/177.out
@@ -5,8 +5,8 @@ Formatting 'TEST_DIR/t.IMGFMT.base', fmt=IMGFMT size=134217728
 wrote 134217728/134217728 bytes at offset 0
 128 MiB, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
 Formatting 'TEST_DIR/t.IMGFMT', fmt=IMGFMT size=134217728 backing_file=TEST_DIR/t.IMGFMT.base
-wrote 134217728/134217728 bytes at offset 0
-128 MiB, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
+wrote 115343360/115343360 bytes at offset 0
+110 MiB, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
 
 == constrained alignment and max-transfer ==
 wrote 131072/131072 bytes at offset 1000
@@ -26,6 +26,13 @@ wrote 33554432/33554432 bytes at offset 33554432
 discard 31457280/31457280 bytes at offset 80000001
 30 MiB, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
 
+== block status smaller than alignment ==
+1/1 bytes allocated at offset 1 bytes
+16/1000 bytes allocated at offset 110 MiB
+0/1048576 bytes allocated at offset 127 MiB
+110 MiB (0x6e00000) bytes     allocated at offset 0 bytes (0x0)
+18 MiB (0x1200000) bytes not allocated at offset 110 MiB (0x6e00000)
+
 == verify image content ==
 read 1000/1000 bytes at offset 0
 1000 bytes, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
@@ -43,12 +50,14 @@ read 13631488/13631488 bytes at offset 67108864
 13 MiB, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
 read 30408704/30408704 bytes at offset 80740352
 29 MiB, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
-read 23068672/23068672 bytes at offset 111149056
-22 MiB, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
+read 4194304/4194304 bytes at offset 111149056
+4 MiB, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
+read 18874368/18874368 bytes at offset 115343360
+18 MiB, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
 Offset          Length          File
 0               0x800000        TEST_DIR/t.IMGFMT
 0x900000        0x2400000       TEST_DIR/t.IMGFMT
 0x3c00000       0x1100000       TEST_DIR/t.IMGFMT
-0x6a00000       0x1600000       TEST_DIR/t.IMGFMT
+0x6a00000       0x400000        TEST_DIR/t.IMGFMT
 No errors were found on the image.
 *** done
diff --git a/tests/qemu-iotests/184 b/tests/qemu-iotests/184
index 704f38f936..ee96c99af3 100755
--- a/tests/qemu-iotests/184
+++ b/tests/qemu-iotests/184
@@ -51,7 +51,8 @@ function do_run_qemu()
 function run_qemu()
 {
     do_run_qemu "$@" 2>&1 | _filter_testdir | _filter_qemu | _filter_qmp\
-                          | _filter_qemu_io | _filter_generated_node_ids
+                          | _filter_qemu_io | _filter_generated_node_ids \
+                          | _filter_actual_image_size
 }
 
 _make_test_img 64M
diff --git a/tests/qemu-iotests/184.out b/tests/qemu-iotests/184.out
index 0aed1a2220..4dc7984a85 100644
--- a/tests/qemu-iotests/184.out
+++ b/tests/qemu-iotests/184.out
@@ -32,7 +32,7 @@ Testing:
                 "filename": "json:{\"throttle-group\": \"group0\", \"driver\": \"throttle\", \"file\": {\"driver\": \"qcow2\", \"file\": {\"driver\": \"file\", \"filename\": \"TEST_DIR/t.qcow2\"}}}",
                 "cluster-size": 65536,
                 "format": "throttle",
-                "actual-size": 200704,
+                "actual-size": SIZE,
                 "dirty-flag": false
             },
             "iops_wr": 0,
@@ -62,7 +62,7 @@ Testing:
                 "filename": "TEST_DIR/t.qcow2",
                 "cluster-size": 65536,
                 "format": "qcow2",
-                "actual-size": 200704,
+                "actual-size": SIZE,
                 "format-specific": {
                     "type": "qcow2",
                     "data": {
@@ -100,7 +100,7 @@ Testing:
                 "virtual-size": 197120,
                 "filename": "TEST_DIR/t.qcow2",
                 "format": "file",
-                "actual-size": 200704,
+                "actual-size": SIZE,
                 "dirty-flag": false
             },
             "iops_wr": 0,
diff --git a/tests/qemu-iotests/191 b/tests/qemu-iotests/191
index ac2b88fd78..ad785e10b1 100755
--- a/tests/qemu-iotests/191
+++ b/tests/qemu-iotests/191
@@ -56,7 +56,8 @@ echo === Preparing and starting VM ===
 echo
 
 TEST_IMG="${TEST_IMG}.base" _make_test_img $size
-TEST_IMG="${TEST_IMG}.mid" _make_test_img -b "${TEST_IMG}.base"
+IMGOPTS=$(_optstr_add "$IMGOPTS" "backing_fmt=$IMGFMT") \
+    TEST_IMG="${TEST_IMG}.mid" _make_test_img -b "${TEST_IMG}.base"
 _make_test_img -b "${TEST_IMG}.mid"
 TEST_IMG="${TEST_IMG}.ovl2" _make_test_img -b "${TEST_IMG}.mid"
 
@@ -91,7 +92,7 @@ echo === Check that both top and top2 point to base now ===
 echo
 
 _send_qemu_cmd $h "{ 'execute': 'query-named-block-nodes' }" "^}" |
-    _filter_generated_node_ids
+    _filter_generated_node_ids | _filter_actual_image_size
 
 _send_qemu_cmd $h "{ 'execute': 'quit' }" "^}"
 wait=1 _cleanup_qemu
@@ -139,7 +140,7 @@ echo === Check that both top and top2 point to base now ===
 echo
 
 _send_qemu_cmd $h "{ 'execute': 'query-named-block-nodes' }" "^}" |
-    _filter_generated_node_ids
+    _filter_generated_node_ids | _filter_actual_image_size
 
 _send_qemu_cmd $h "{ 'execute': 'quit' }" "^}"
 wait=1 _cleanup_qemu
diff --git a/tests/qemu-iotests/191.out b/tests/qemu-iotests/191.out
index 7bfcd2d5d8..73c0ed454c 100644
--- a/tests/qemu-iotests/191.out
+++ b/tests/qemu-iotests/191.out
@@ -3,7 +3,7 @@ QA output created by 191
 === Preparing and starting VM ===
 
 Formatting 'TEST_DIR/t.IMGFMT.base', fmt=IMGFMT size=67108864
-Formatting 'TEST_DIR/t.IMGFMT.mid', fmt=IMGFMT size=67108864 backing_file=TEST_DIR/t.IMGFMT.base
+Formatting 'TEST_DIR/t.IMGFMT.mid', fmt=IMGFMT size=67108864 backing_file=TEST_DIR/t.IMGFMT.base backing_fmt=IMGFMT
 Formatting 'TEST_DIR/t.IMGFMT', fmt=IMGFMT size=67108864 backing_file=TEST_DIR/t.IMGFMT.mid
 Formatting 'TEST_DIR/t.IMGFMT.ovl2', fmt=IMGFMT size=67108864 backing_file=TEST_DIR/t.IMGFMT.mid
 wrote 65536/65536 bytes at offset 1048576
@@ -47,7 +47,7 @@ wrote 65536/65536 bytes at offset 1048576
                     "filename": "TEST_DIR/t.qcow2.base",
                     "cluster-size": 65536,
                     "format": "qcow2",
-                    "actual-size": 397312,
+                    "actual-size": SIZE,
                     "format-specific": {
                         "type": "qcow2",
                         "data": {
@@ -64,7 +64,7 @@ wrote 65536/65536 bytes at offset 1048576
                 "filename": "TEST_DIR/t.qcow2.ovl2",
                 "cluster-size": 65536,
                 "format": "qcow2",
-                "actual-size": 200704,
+                "actual-size": SIZE,
                 "format-specific": {
                     "type": "qcow2",
                     "data": {
@@ -105,7 +105,7 @@ wrote 65536/65536 bytes at offset 1048576
                 "virtual-size": 197120,
                 "filename": "TEST_DIR/t.qcow2.ovl2",
                 "format": "file",
-                "actual-size": 200704,
+                "actual-size": SIZE,
                 "dirty-flag": false
             },
             "iops_wr": 0,
@@ -136,7 +136,7 @@ wrote 65536/65536 bytes at offset 1048576
                     "filename": "TEST_DIR/t.qcow2.base",
                     "cluster-size": 65536,
                     "format": "qcow2",
-                    "actual-size": 397312,
+                    "actual-size": SIZE,
                     "format-specific": {
                         "type": "qcow2",
                         "data": {
@@ -153,7 +153,7 @@ wrote 65536/65536 bytes at offset 1048576
                 "filename": "TEST_DIR/t.qcow2",
                 "cluster-size": 65536,
                 "format": "qcow2",
-                "actual-size": 200704,
+                "actual-size": SIZE,
                 "format-specific": {
                     "type": "qcow2",
                     "data": {
@@ -194,7 +194,7 @@ wrote 65536/65536 bytes at offset 1048576
                 "virtual-size": 197120,
                 "filename": "TEST_DIR/t.qcow2",
                 "format": "file",
-                "actual-size": 200704,
+                "actual-size": SIZE,
                 "dirty-flag": false
             },
             "iops_wr": 0,
@@ -225,7 +225,7 @@ wrote 65536/65536 bytes at offset 1048576
                     "filename": "TEST_DIR/t.qcow2.base",
                     "cluster-size": 65536,
                     "format": "qcow2",
-                    "actual-size": 397312,
+                    "actual-size": SIZE,
                     "format-specific": {
                         "type": "qcow2",
                         "data": {
@@ -242,7 +242,7 @@ wrote 65536/65536 bytes at offset 1048576
                 "filename": "TEST_DIR/t.qcow2.mid",
                 "cluster-size": 65536,
                 "format": "qcow2",
-                "actual-size": 397312,
+                "actual-size": SIZE,
                 "format-specific": {
                     "type": "qcow2",
                     "data": {
@@ -283,7 +283,7 @@ wrote 65536/65536 bytes at offset 1048576
                 "virtual-size": 393216,
                 "filename": "TEST_DIR/t.qcow2.mid",
                 "format": "file",
-                "actual-size": 397312,
+                "actual-size": SIZE,
                 "dirty-flag": false
             },
             "iops_wr": 0,
@@ -313,7 +313,7 @@ wrote 65536/65536 bytes at offset 1048576
                 "filename": "TEST_DIR/t.qcow2.base",
                 "cluster-size": 65536,
                 "format": "qcow2",
-                "actual-size": 397312,
+                "actual-size": SIZE,
                 "format-specific": {
                     "type": "qcow2",
                     "data": {
@@ -351,7 +351,7 @@ wrote 65536/65536 bytes at offset 1048576
                 "virtual-size": 393216,
                 "filename": "TEST_DIR/t.qcow2.base",
                 "format": "file",
-                "actual-size": 397312,
+                "actual-size": SIZE,
                 "dirty-flag": false
             },
             "iops_wr": 0,
@@ -450,7 +450,7 @@ wrote 65536/65536 bytes at offset 1048576
                     "filename": "TEST_DIR/t.qcow2.base",
                     "cluster-size": 65536,
                     "format": "qcow2",
-                    "actual-size": 397312,
+                    "actual-size": SIZE,
                     "format-specific": {
                         "type": "qcow2",
                         "data": {
@@ -467,7 +467,7 @@ wrote 65536/65536 bytes at offset 1048576
                 "filename": "TEST_DIR/t.qcow2.ovl2",
                 "cluster-size": 65536,
                 "format": "qcow2",
-                "actual-size": 200704,
+                "actual-size": SIZE,
                 "format-specific": {
                     "type": "qcow2",
                     "data": {
@@ -508,7 +508,7 @@ wrote 65536/65536 bytes at offset 1048576
                 "virtual-size": 197120,
                 "filename": "TEST_DIR/t.qcow2.ovl2",
                 "format": "file",
-                "actual-size": 200704,
+                "actual-size": SIZE,
                 "dirty-flag": false
             },
             "iops_wr": 0,
@@ -540,7 +540,7 @@ wrote 65536/65536 bytes at offset 1048576
                         "filename": "TEST_DIR/t.qcow2.base",
                         "cluster-size": 65536,
                         "format": "qcow2",
-                        "actual-size": 397312,
+                        "actual-size": SIZE,
                         "format-specific": {
                             "type": "qcow2",
                             "data": {
@@ -557,7 +557,7 @@ wrote 65536/65536 bytes at offset 1048576
                     "filename": "TEST_DIR/t.qcow2.ovl2",
                     "cluster-size": 65536,
                     "format": "qcow2",
-                    "actual-size": 200704,
+                    "actual-size": SIZE,
                     "format-specific": {
                         "type": "qcow2",
                         "data": {
@@ -576,7 +576,7 @@ wrote 65536/65536 bytes at offset 1048576
                 "filename": "TEST_DIR/t.qcow2.ovl3",
                 "cluster-size": 65536,
                 "format": "qcow2",
-                "actual-size": 200704,
+                "actual-size": SIZE,
                 "format-specific": {
                     "type": "qcow2",
                     "data": {
@@ -617,7 +617,7 @@ wrote 65536/65536 bytes at offset 1048576
                 "virtual-size": 197120,
                 "filename": "TEST_DIR/t.qcow2.ovl3",
                 "format": "file",
-                "actual-size": 200704,
+                "actual-size": SIZE,
                 "dirty-flag": false
             },
             "iops_wr": 0,
@@ -647,7 +647,7 @@ wrote 65536/65536 bytes at offset 1048576
                 "filename": "TEST_DIR/t.qcow2.base",
                 "cluster-size": 65536,
                 "format": "qcow2",
-                "actual-size": 397312,
+                "actual-size": SIZE,
                 "format-specific": {
                     "type": "qcow2",
                     "data": {
@@ -685,7 +685,7 @@ wrote 65536/65536 bytes at offset 1048576
                 "virtual-size": 393216,
                 "filename": "TEST_DIR/t.qcow2.base",
                 "format": "file",
-                "actual-size": 397312,
+                "actual-size": SIZE,
                 "dirty-flag": false
             },
             "iops_wr": 0,
@@ -716,7 +716,7 @@ wrote 65536/65536 bytes at offset 1048576
                     "filename": "TEST_DIR/t.qcow2.base",
                     "cluster-size": 65536,
                     "format": "qcow2",
-                    "actual-size": 397312,
+                    "actual-size": SIZE,
                     "format-specific": {
                         "type": "qcow2",
                         "data": {
@@ -733,7 +733,7 @@ wrote 65536/65536 bytes at offset 1048576
                 "filename": "TEST_DIR/t.qcow2",
                 "cluster-size": 65536,
                 "format": "qcow2",
-                "actual-size": 200704,
+                "actual-size": SIZE,
                 "format-specific": {
                     "type": "qcow2",
                     "data": {
@@ -774,7 +774,7 @@ wrote 65536/65536 bytes at offset 1048576
                 "virtual-size": 197120,
                 "filename": "TEST_DIR/t.qcow2",
                 "format": "file",
-                "actual-size": 200704,
+                "actual-size": SIZE,
                 "dirty-flag": false
             },
             "iops_wr": 0,
diff --git a/tests/qemu-iotests/common.filter b/tests/qemu-iotests/common.filter
index 227b37e941..873ca6b104 100644
--- a/tests/qemu-iotests/common.filter
+++ b/tests/qemu-iotests/common.filter
@@ -105,6 +105,12 @@ _filter_block_job_len()
     sed -e 's/, "len": [0-9]\+,/, "len": LEN,/g'
 }
 
+# replace actual image size (depends on the host filesystem)
+_filter_actual_image_size()
+{
+    sed -s 's/\("actual-size":\s*\)[0-9]\+/\1SIZE/g'
+}
+
 # replace driver-specific options in the "Formatting..." line
 _filter_img_create()
 {
diff --git a/tests/qemu-iotests/group b/tests/qemu-iotests/group
index 83da427c0a..24e5ad1b79 100644
--- a/tests/qemu-iotests/group
+++ b/tests/qemu-iotests/group
@@ -133,6 +133,7 @@
 124 rw auto backing
 125 rw auto
 126 rw auto backing
+127 rw auto backing quick
 128 rw auto quick
 129 rw auto quick
 130 rw auto quick