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GET /api/patches/813529/?format=api
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{
    "id": 813529,
    "url": "http://patchwork.ozlabs.org/api/patches/813529/?format=api",
    "web_url": "http://patchwork.ozlabs.org/project/qemu-devel/patch/20170913160333.23622-13-eblake@redhat.com/",
    "project": {
        "id": 14,
        "url": "http://patchwork.ozlabs.org/api/projects/14/?format=api",
        "name": "QEMU Development",
        "link_name": "qemu-devel",
        "list_id": "qemu-devel.nongnu.org",
        "list_email": "qemu-devel@nongnu.org",
        "web_url": "",
        "scm_url": "",
        "webscm_url": "",
        "list_archive_url": "",
        "list_archive_url_format": "",
        "commit_url_format": ""
    },
    "msgid": "<20170913160333.23622-13-eblake@redhat.com>",
    "list_archive_url": null,
    "date": "2017-09-13T16:03:22",
    "name": "[v4,12/23] block: Convert bdrv_get_block_status_above() to bytes",
    "commit_ref": null,
    "pull_url": null,
    "state": "new",
    "archived": false,
    "hash": "051eab4ee62c85a43a7671cbfca74d628ab84fff",
    "submitter": {
        "id": 6591,
        "url": "http://patchwork.ozlabs.org/api/people/6591/?format=api",
        "name": "Eric Blake",
        "email": "eblake@redhat.com"
    },
    "delegate": null,
    "mbox": "http://patchwork.ozlabs.org/project/qemu-devel/patch/20170913160333.23622-13-eblake@redhat.com/mbox/",
    "series": [
        {
            "id": 2944,
            "url": "http://patchwork.ozlabs.org/api/series/2944/?format=api",
            "web_url": "http://patchwork.ozlabs.org/project/qemu-devel/list/?series=2944",
            "date": "2017-09-13T16:03:10",
            "name": "make bdrv_get_block_status byte-based",
            "version": 4,
            "mbox": "http://patchwork.ozlabs.org/series/2944/mbox/"
        }
    ],
    "comments": "http://patchwork.ozlabs.org/api/patches/813529/comments/",
    "check": "pending",
    "checks": "http://patchwork.ozlabs.org/api/patches/813529/checks/",
    "tags": {},
    "related": [],
    "headers": {
        "Return-Path": "<qemu-devel-bounces+incoming=patchwork.ozlabs.org@nongnu.org>",
        "X-Original-To": "incoming@patchwork.ozlabs.org",
        "Delivered-To": "patchwork-incoming@bilbo.ozlabs.org",
        "Authentication-Results": [
            "ozlabs.org;\n\tspf=pass (mailfrom) smtp.mailfrom=nongnu.org\n\t(client-ip=2001:4830:134:3::11; helo=lists.gnu.org;\n\tenvelope-from=qemu-devel-bounces+incoming=patchwork.ozlabs.org@nongnu.org;\n\treceiver=<UNKNOWN>)",
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            "ext-mx07.extmail.prod.ext.phx2.redhat.com;\n\tspf=fail smtp.mailfrom=eblake@redhat.com"
        ],
        "Received": [
            "from lists.gnu.org (lists.gnu.org [IPv6:2001:4830:134:3::11])\n\t(using TLSv1 with cipher AES256-SHA (256/256 bits))\n\t(No client certificate requested)\n\tby ozlabs.org (Postfix) with ESMTPS id 3xsn6Z5tgYz9s7M\n\tfor <incoming@patchwork.ozlabs.org>;\n\tThu, 14 Sep 2017 02:24:06 +1000 (AEST)",
            "from localhost ([::1]:43454 helo=lists.gnu.org)\n\tby lists.gnu.org with esmtp (Exim 4.71) (envelope-from\n\t<qemu-devel-bounces+incoming=patchwork.ozlabs.org@nongnu.org>)\n\tid 1dsASK-0004yk-Qz\n\tfor incoming@patchwork.ozlabs.org; Wed, 13 Sep 2017 12:24:04 -0400",
            "from eggs.gnu.org ([2001:4830:134:3::10]:46050)\n\tby lists.gnu.org with esmtp (Exim 4.71)\n\t(envelope-from <eblake@redhat.com>) id 1dsA9h-000227-1v\n\tfor qemu-devel@nongnu.org; Wed, 13 Sep 2017 12:04:50 -0400",
            "from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71)\n\t(envelope-from <eblake@redhat.com>) id 1dsA9a-0006KQ-Kr\n\tfor qemu-devel@nongnu.org; Wed, 13 Sep 2017 12:04:49 -0400",
            "from mx1.redhat.com ([209.132.183.28]:49971)\n\tby eggs.gnu.org with esmtps (TLS1.0:DHE_RSA_AES_256_CBC_SHA1:32)\n\t(Exim 4.71) (envelope-from <eblake@redhat.com>)\n\tid 1dsA9M-0006BZ-UL; Wed, 13 Sep 2017 12:04:29 -0400",
            "from smtp.corp.redhat.com\n\t(int-mx01.intmail.prod.int.phx2.redhat.com [10.5.11.11])\n\t(using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits))\n\t(No client certificate requested)\n\tby mx1.redhat.com (Postfix) with ESMTPS id F36C7C047B88;\n\tWed, 13 Sep 2017 16:04:27 +0000 (UTC)",
            "from red.redhat.com (ovpn-120-201.rdu2.redhat.com [10.10.120.201])\n\tby smtp.corp.redhat.com (Postfix) with ESMTP id 4661D5C6D2;\n\tWed, 13 Sep 2017 16:04:26 +0000 (UTC)"
        ],
        "DMARC-Filter": "OpenDMARC Filter v1.3.2 mx1.redhat.com F36C7C047B88",
        "From": "Eric Blake <eblake@redhat.com>",
        "To": "qemu-devel@nongnu.org",
        "Date": "Wed, 13 Sep 2017 11:03:22 -0500",
        "Message-Id": "<20170913160333.23622-13-eblake@redhat.com>",
        "In-Reply-To": "<20170913160333.23622-1-eblake@redhat.com>",
        "References": "<20170913160333.23622-1-eblake@redhat.com>",
        "X-Scanned-By": "MIMEDefang 2.79 on 10.5.11.11",
        "X-Greylist": "Sender IP whitelisted, not delayed by milter-greylist-4.5.16\n\t(mx1.redhat.com [10.5.110.31]);\n\tWed, 13 Sep 2017 16:04:28 +0000 (UTC)",
        "X-detected-operating-system": "by eggs.gnu.org: GNU/Linux 2.2.x-3.x [generic]\n\t[fuzzy]",
        "X-Received-From": "209.132.183.28",
        "Subject": "[Qemu-devel] [PATCH v4 12/23] block: Convert\n\tbdrv_get_block_status_above() to bytes",
        "X-BeenThere": "qemu-devel@nongnu.org",
        "X-Mailman-Version": "2.1.21",
        "Precedence": "list",
        "List-Id": "<qemu-devel.nongnu.org>",
        "List-Unsubscribe": "<https://lists.nongnu.org/mailman/options/qemu-devel>,\n\t<mailto:qemu-devel-request@nongnu.org?subject=unsubscribe>",
        "List-Archive": "<http://lists.nongnu.org/archive/html/qemu-devel/>",
        "List-Post": "<mailto:qemu-devel@nongnu.org>",
        "List-Help": "<mailto:qemu-devel-request@nongnu.org?subject=help>",
        "List-Subscribe": "<https://lists.nongnu.org/mailman/listinfo/qemu-devel>,\n\t<mailto:qemu-devel-request@nongnu.org?subject=subscribe>",
        "Cc": "kwolf@redhat.com, famz@redhat.com, qemu-block@nongnu.org,\n\tJeff Cody <jcody@redhat.com>, Max Reitz <mreitz@redhat.com>,\n\tStefan Hajnoczi <stefanha@redhat.com>, jsnow@redhat.com",
        "Errors-To": "qemu-devel-bounces+incoming=patchwork.ozlabs.org@nongnu.org",
        "Sender": "\"Qemu-devel\"\n\t<qemu-devel-bounces+incoming=patchwork.ozlabs.org@nongnu.org>"
    },
    "content": "We are gradually moving away from sector-based interfaces, towards\nbyte-based.  In the common case, allocation is unlikely to ever use\nvalues that are not naturally sector-aligned, but it is possible\nthat byte-based values will let us be more precise about allocation\nat the end of an unaligned file that can do byte-based access.\n\nChanging the name of the function from bdrv_get_block_status_above()\nto bdrv_block_status_above() ensures that the compiler enforces that\nall callers are updated.  For now, the io.c layer still assert()s\nthat all callers are sector-aligned, but that can be relaxed when a\nlater patch implements byte-based block status in the drivers.\n\nFor the most part this patch is just the addition of scaling at the\ncallers followed by inverse scaling at bdrv_block_status().  But some\ncode, particularly bdrv_block_status(), gets a lot simpler because\nit no longer has to mess with sectors.  Likewise, mirror code no\nlonger computes s->granularity >> BDRV_SECTOR_BITS, and can therefore\ndrop an assertion (fix a neighboring assertion to use is_power_of_2\nwhile there).\n\nFor ease of review, bdrv_get_block_status() was tackled separately.\n\nSigned-off-by: Eric Blake <eblake@redhat.com>\n\n---\nv4: rebase to earlier changes\nv3: rebase to allocation/mapping sense change and qcow2-measure, tweak\nmirror assertions, drop R-b\nv2: rebase to earlier changes\n---\n include/block/block.h | 10 +++++-----\n block/io.c            | 39 ++++++++-------------------------------\n block/mirror.c        | 16 +++++-----------\n block/qcow2.c         | 25 +++++++++----------------\n qemu-img.c            | 39 +++++++++++++++++++++++----------------\n 5 files changed, 50 insertions(+), 79 deletions(-)",
    "diff": "diff --git a/include/block/block.h b/include/block/block.h\nindex 7a9a8db588..e87348dcfa 100644\n--- a/include/block/block.h\n+++ b/include/block/block.h\n@@ -426,11 +426,11 @@ bool bdrv_can_write_zeroes_with_unmap(BlockDriverState *bs);\n int64_t bdrv_block_status(BlockDriverState *bs, int64_t offset,\n                           int64_t bytes, int64_t *pnum,\n                           BlockDriverState **file);\n-int64_t bdrv_get_block_status_above(BlockDriverState *bs,\n-                                    BlockDriverState *base,\n-                                    int64_t sector_num,\n-                                    int nb_sectors, int *pnum,\n-                                    BlockDriverState **file);\n+int64_t bdrv_block_status_above(BlockDriverState *bs,\n+                                BlockDriverState *base,\n+                                int64_t offset,\n+                                int64_t bytes, int64_t *pnum,\n+                                BlockDriverState **file);\n int bdrv_is_allocated(BlockDriverState *bs, int64_t offset, int64_t bytes,\n                       int64_t *pnum);\n int bdrv_is_allocated_above(BlockDriverState *top, BlockDriverState *base,\ndiff --git a/block/io.c b/block/io.c\nindex 409cfe0938..ea63d19480 100644\n--- a/block/io.c\n+++ b/block/io.c\n@@ -1931,7 +1931,7 @@ static int64_t coroutine_fn bdrv_co_block_status_above(BlockDriverState *bs,\n     return ret;\n }\n\n-/* Coroutine wrapper for bdrv_get_block_status_above() */\n+/* Coroutine wrapper for bdrv_block_status_above() */\n static void coroutine_fn bdrv_block_status_above_co_entry(void *opaque)\n {\n     BdrvCoBlockStatusData *data = opaque;\n@@ -1978,43 +1978,20 @@ static int64_t bdrv_common_block_status_above(BlockDriverState *bs,\n     return data.ret;\n }\n\n-int64_t bdrv_get_block_status_above(BlockDriverState *bs,\n-                                    BlockDriverState *base,\n-                                    int64_t sector_num,\n-                                    int nb_sectors, int *pnum,\n-                                    BlockDriverState **file)\n+int64_t bdrv_block_status_above(BlockDriverState *bs, BlockDriverState *base,\n+                                int64_t offset, int64_t bytes, int64_t *pnum,\n+                                BlockDriverState **file)\n {\n-    int64_t ret;\n-    int64_t n;\n-\n-    ret = bdrv_common_block_status_above(bs, base, true,\n-                                         sector_num * BDRV_SECTOR_SIZE,\n-                                         nb_sectors * BDRV_SECTOR_SIZE,\n-                                         &n, file);\n-    if (ret < 0) {\n-        return ret;\n-    }\n-    assert(QEMU_IS_ALIGNED(n, BDRV_SECTOR_SIZE));\n-    *pnum = n >> BDRV_SECTOR_BITS;\n-    return ret;\n+    return bdrv_common_block_status_above(bs, base, true, offset, bytes,\n+                                          pnum, file);\n }\n\n int64_t bdrv_block_status(BlockDriverState *bs,\n                           int64_t offset, int64_t bytes, int64_t *pnum,\n                           BlockDriverState **file)\n {\n-    int64_t ret;\n-    int n;\n-\n-    assert(QEMU_IS_ALIGNED(offset | bytes, BDRV_SECTOR_SIZE));\n-    bytes = MIN(bytes, BDRV_REQUEST_MAX_BYTES);\n-    ret = bdrv_get_block_status_above(bs, backing_bs(bs),\n-                                      offset >> BDRV_SECTOR_BITS,\n-                                      bytes >> BDRV_SECTOR_BITS, &n, file);\n-    if (pnum) {\n-        *pnum = n * BDRV_SECTOR_SIZE;\n-    }\n-    return ret;\n+    return bdrv_block_status_above(bs, backing_bs(bs),\n+                                   offset, bytes, pnum, file);\n }\n\n int coroutine_fn bdrv_is_allocated(BlockDriverState *bs, int64_t offset,\ndiff --git a/block/mirror.c b/block/mirror.c\nindex 67f45cec4e..fab59739c5 100644\n--- a/block/mirror.c\n+++ b/block/mirror.c\n@@ -328,7 +328,6 @@ static uint64_t coroutine_fn mirror_iteration(MirrorBlockJob *s)\n     uint64_t delay_ns = 0;\n     /* At least the first dirty chunk is mirrored in one iteration. */\n     int nb_chunks = 1;\n-    int sectors_per_chunk = s->granularity >> BDRV_SECTOR_BITS;\n     bool write_zeroes_ok = bdrv_can_write_zeroes_with_unmap(blk_bs(s->target));\n     int max_io_bytes = MAX(s->buf_size / MAX_IN_FLIGHT, MAX_IO_BYTES);\n\n@@ -376,7 +375,7 @@ static uint64_t coroutine_fn mirror_iteration(MirrorBlockJob *s)\n     }\n\n     /* Clear dirty bits before querying the block status, because\n-     * calling bdrv_get_block_status_above could yield - if some blocks are\n+     * calling bdrv_block_status_above could yield - if some blocks are\n      * marked dirty in this window, we need to know.\n      */\n     bdrv_reset_dirty_bitmap_locked(s->dirty_bitmap, offset,\n@@ -386,7 +385,6 @@ static uint64_t coroutine_fn mirror_iteration(MirrorBlockJob *s)\n     bitmap_set(s->in_flight_bitmap, offset / s->granularity, nb_chunks);\n     while (nb_chunks > 0 && offset < s->bdev_length) {\n         int64_t ret;\n-        int io_sectors;\n         int64_t io_bytes;\n         int64_t io_bytes_acct;\n         enum MirrorMethod {\n@@ -396,11 +394,9 @@ static uint64_t coroutine_fn mirror_iteration(MirrorBlockJob *s)\n         } mirror_method = MIRROR_METHOD_COPY;\n\n         assert(!(offset % s->granularity));\n-        ret = bdrv_get_block_status_above(source, NULL,\n-                                          offset >> BDRV_SECTOR_BITS,\n-                                          nb_chunks * sectors_per_chunk,\n-                                          &io_sectors, NULL);\n-        io_bytes = io_sectors * BDRV_SECTOR_SIZE;\n+        ret = bdrv_block_status_above(source, NULL, offset,\n+                                      nb_chunks * s->granularity,\n+                                      &io_bytes, NULL);\n         if (ret < 0) {\n             io_bytes = MIN(nb_chunks * s->granularity, max_io_bytes);\n         } else if (ret & BDRV_BLOCK_DATA) {\n@@ -1121,9 +1117,7 @@ static void mirror_start_job(const char *job_id, BlockDriverState *bs,\n         granularity = bdrv_get_default_bitmap_granularity(target);\n     }\n\n-    assert ((granularity & (granularity - 1)) == 0);\n-    /* Granularity must be large enough for sector-based dirty bitmap */\n-    assert(granularity >= BDRV_SECTOR_SIZE);\n+    assert(is_power_of_2(granularity));\n\n     if (buf_size < 0) {\n         error_setg(errp, \"Invalid parameter 'buf-size'\");\ndiff --git a/block/qcow2.c b/block/qcow2.c\nindex eb498b56d4..721cb077fe 100644\n--- a/block/qcow2.c\n+++ b/block/qcow2.c\n@@ -2973,7 +2973,7 @@ finish:\n\n static bool is_zero(BlockDriverState *bs, int64_t offset, int64_t bytes)\n {\n-    int nr;\n+    int64_t nr;\n     int64_t res;\n     int64_t start;\n\n@@ -2989,10 +2989,8 @@ static bool is_zero(BlockDriverState *bs, int64_t offset, int64_t bytes)\n     if (!bytes) {\n         return true;\n     }\n-    res = bdrv_get_block_status_above(bs, NULL, start >> BDRV_SECTOR_BITS,\n-                                      bytes >> BDRV_SECTOR_BITS, &nr, NULL);\n-    return res >= 0 && (res & BDRV_BLOCK_ZERO) &&\n-        nr * BDRV_SECTOR_SIZE == bytes;\n+    res = bdrv_block_status_above(bs, NULL, start, bytes, &nr, NULL);\n+    return res >= 0 && (res & BDRV_BLOCK_ZERO) && nr == bytes;\n }\n\n static coroutine_fn int qcow2_co_pwrite_zeroes(BlockDriverState *bs,\n@@ -3650,17 +3648,13 @@ static BlockMeasureInfo *qcow2_measure(QemuOpts *opts, BlockDriverState *in_bs,\n             required = virtual_size;\n         } else {\n             int64_t offset;\n-            int pnum = 0;\n+            int64_t pnum = 0;\n\n-            for (offset = 0; offset < ssize;\n-                 offset += pnum * BDRV_SECTOR_SIZE) {\n-                int nb_sectors = MIN(ssize - offset,\n-                                     BDRV_REQUEST_MAX_BYTES) / BDRV_SECTOR_SIZE;\n+            for (offset = 0; offset < ssize; offset += pnum) {\n                 int64_t ret;\n\n-                ret = bdrv_get_block_status_above(in_bs, NULL,\n-                                                  offset >> BDRV_SECTOR_BITS,\n-                                                  nb_sectors, &pnum, NULL);\n+                ret = bdrv_block_status_above(in_bs, NULL, offset,\n+                                              ssize - offset, &pnum, NULL);\n                 if (ret < 0) {\n                     error_setg_errno(&local_err, -ret,\n                                      \"Unable to get block status\");\n@@ -3672,11 +3666,10 @@ static BlockMeasureInfo *qcow2_measure(QemuOpts *opts, BlockDriverState *in_bs,\n                 } else if ((ret & (BDRV_BLOCK_DATA | BDRV_BLOCK_ALLOCATED)) ==\n                            (BDRV_BLOCK_DATA | BDRV_BLOCK_ALLOCATED)) {\n                     /* Extend pnum to end of cluster for next iteration */\n-                    pnum = (ROUND_UP(offset + pnum * BDRV_SECTOR_SIZE,\n-                                 cluster_size) - offset) >> BDRV_SECTOR_BITS;\n+                    pnum = ROUND_UP(offset + pnum, cluster_size) - offset;\n\n                     /* Count clusters we've seen */\n-                    required += offset % cluster_size + pnum * BDRV_SECTOR_SIZE;\n+                    required += offset % cluster_size + pnum;\n                 }\n             }\n         }\ndiff --git a/qemu-img.c b/qemu-img.c\nindex 897f80abb3..b91133b922 100644\n--- a/qemu-img.c\n+++ b/qemu-img.c\n@@ -1225,7 +1225,7 @@ static int img_compare(int argc, char **argv)\n     BlockDriverState *bs1, *bs2;\n     int64_t total_sectors1, total_sectors2;\n     uint8_t *buf1 = NULL, *buf2 = NULL;\n-    int pnum1, pnum2;\n+    int64_t pnum1, pnum2;\n     int allocated1, allocated2;\n     int ret = 0; /* return value - 0 Ident, 1 Different, >1 Error */\n     bool progress = false, quiet = false, strict = false;\n@@ -1379,9 +1379,11 @@ static int img_compare(int argc, char **argv)\n         if (nb_sectors <= 0) {\n             break;\n         }\n-        status1 = bdrv_get_block_status_above(bs1, NULL, sector_num,\n-                                              total_sectors1 - sector_num,\n-                                              &pnum1, NULL);\n+        status1 = bdrv_block_status_above(bs1, NULL,\n+                                          sector_num * BDRV_SECTOR_SIZE,\n+                                          (total_sectors1 - sector_num) *\n+                                          BDRV_SECTOR_SIZE,\n+                                          &pnum1, NULL);\n         if (status1 < 0) {\n             ret = 3;\n             error_report(\"Sector allocation test failed for %s\", filename1);\n@@ -1389,9 +1391,11 @@ static int img_compare(int argc, char **argv)\n         }\n         allocated1 = status1 & BDRV_BLOCK_ALLOCATED;\n\n-        status2 = bdrv_get_block_status_above(bs2, NULL, sector_num,\n-                                              total_sectors2 - sector_num,\n-                                              &pnum2, NULL);\n+        status2 = bdrv_block_status_above(bs2, NULL,\n+                                          sector_num * BDRV_SECTOR_SIZE,\n+                                          (total_sectors2 - sector_num) *\n+                                          BDRV_SECTOR_SIZE,\n+                                          &pnum2, NULL);\n         if (status2 < 0) {\n             ret = 3;\n             error_report(\"Sector allocation test failed for %s\", filename2);\n@@ -1399,10 +1403,12 @@ static int img_compare(int argc, char **argv)\n         }\n         allocated2 = status2 & BDRV_BLOCK_ALLOCATED;\n         if (pnum1) {\n-            nb_sectors = MIN(nb_sectors, pnum1);\n+            nb_sectors = MIN(nb_sectors,\n+                             DIV_ROUND_UP(pnum1, BDRV_SECTOR_SIZE));\n         }\n         if (pnum2) {\n-            nb_sectors = MIN(nb_sectors, pnum2);\n+            nb_sectors = MIN(nb_sectors,\n+                             DIV_ROUND_UP(pnum2, BDRV_SECTOR_SIZE));\n         }\n\n         if (strict) {\n@@ -1416,7 +1422,7 @@ static int img_compare(int argc, char **argv)\n             }\n         }\n         if ((status1 & BDRV_BLOCK_ZERO) && (status2 & BDRV_BLOCK_ZERO)) {\n-            nb_sectors = MIN(pnum1, pnum2);\n+            nb_sectors = DIV_ROUND_UP(MIN(pnum1, pnum2), BDRV_SECTOR_SIZE);\n         } else if (allocated1 == allocated2) {\n             if (allocated1) {\n                 ret = blk_pread(blk1, sector_num << BDRV_SECTOR_BITS, buf1,\n@@ -1597,23 +1603,24 @@ static int convert_iteration_sectors(ImgConvertState *s, int64_t sector_num)\n     n = MIN(s->total_sectors - sector_num, BDRV_REQUEST_MAX_SECTORS);\n\n     if (s->sector_next_status <= sector_num) {\n+        int64_t count = n * BDRV_SECTOR_SIZE;\n+\n         if (s->target_has_backing) {\n-            int64_t count = n * BDRV_SECTOR_SIZE;\n\n             ret = bdrv_block_status(blk_bs(s->src[src_cur]),\n                                     (sector_num - src_cur_offset) *\n                                     BDRV_SECTOR_SIZE,\n                                     count, &count, NULL);\n-            assert(ret < 0 || QEMU_IS_ALIGNED(count, BDRV_SECTOR_SIZE));\n-            n = count >> BDRV_SECTOR_BITS;\n         } else {\n-            ret = bdrv_get_block_status_above(blk_bs(s->src[src_cur]), NULL,\n-                                              sector_num - src_cur_offset,\n-                                              n, &n, NULL);\n+            ret = bdrv_block_status_above(blk_bs(s->src[src_cur]), NULL,\n+                                          (sector_num - src_cur_offset) *\n+                                          BDRV_SECTOR_SIZE,\n+                                          count, &count, NULL);\n         }\n         if (ret < 0) {\n             return ret;\n         }\n+        n = DIV_ROUND_UP(count, BDRV_SECTOR_SIZE);\n\n         if (ret & BDRV_BLOCK_ZERO) {\n             s->status = BLK_ZERO;\n",
    "prefixes": [
        "v4",
        "12/23"
    ]
}