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GET /api/patches/813506/?format=api
{ "id": 813506, "url": "http://patchwork.ozlabs.org/api/patches/813506/?format=api", "web_url": "http://patchwork.ozlabs.org/project/qemu-devel/patch/20170913160333.23622-2-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": "<20170913160333.23622-2-eblake@redhat.com>", "list_archive_url": null, "date": "2017-09-13T16:03:11", "name": "[v4,01/23] block: Allow NULL file for bdrv_get_block_status()", "commit_ref": null, "pull_url": null, "state": "new", "archived": false, "hash": "dba48d850798830e45771b4f9e9660e6cc51507f", "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/20170913160333.23622-2-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/813506/comments/", "check": "pending", "checks": "http://patchwork.ozlabs.org/api/patches/813506/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>)", "ext-mx08.extmail.prod.ext.phx2.redhat.com;\n\tdmarc=none (p=none dis=none) header.from=redhat.com", "ext-mx08.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 3xsmkR0vQGz9sNV\n\tfor <incoming@patchwork.ozlabs.org>;\n\tThu, 14 Sep 2017 02:06:39 +1000 (AEST)", "from localhost ([::1]:43330 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 1dsABR-00037j-3u\n\tfor incoming@patchwork.ozlabs.org; Wed, 13 Sep 2017 12:06:37 -0400", "from eggs.gnu.org ([2001:4830:134:3::10]:45472)\n\tby lists.gnu.org with esmtp (Exim 4.71)\n\t(envelope-from <eblake@redhat.com>) id 1dsA8q-00014N-3Z\n\tfor qemu-devel@nongnu.org; Wed, 13 Sep 2017 12:04:00 -0400", "from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71)\n\t(envelope-from <eblake@redhat.com>) id 1dsA8j-0005gP-Bu\n\tfor qemu-devel@nongnu.org; Wed, 13 Sep 2017 12:03:56 -0400", "from mx1.redhat.com ([209.132.183.28]:59166)\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 1dsA8f-0005d7-6Z; Wed, 13 Sep 2017 12:03:45 -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 2B6D3C0587DD;\n\tWed, 13 Sep 2017 16:03:44 +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 AC4C35C47C;\n\tWed, 13 Sep 2017 16:03:40 +0000 (UTC)" ], "DMARC-Filter": "OpenDMARC Filter v1.3.2 mx1.redhat.com 2B6D3C0587DD", "From": "Eric Blake <eblake@redhat.com>", "To": "qemu-devel@nongnu.org", "Date": "Wed, 13 Sep 2017 11:03:11 -0500", "Message-Id": "<20170913160333.23622-2-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 [10.5.110.32]);\n\tWed, 13 Sep 2017 16:03:44 +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 01/23] block: Allow NULL file for\n\tbdrv_get_block_status()", "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": "Not all callers care about which BDS owns the mapping for a given\nrange of the file. This patch merely simplifies the callers by\nconsolidating the logic in the common call point, while guaranteeing\na non-NULL file to all the driver callbacks, for no semantic change.\nThe only caller that does not care about pnum is bdrv_is_allocated,\nas invoked by vvfat; we can likewise add assertions that the rest\nof the stack does not have to worry about a NULL pnum.\n\nFurthermore, this will also set the stage for a future cleanup: when\na caller does not care about which BDS owns an offset, it would be\nnice to allow the driver to optimize things to not have to return\nBDRV_BLOCK_OFFSET_VALID in the first place. In the case of fragmented\nallocation (for example, it's fairly easy to create a qcow2 image\nwhere consecutive guest addresses are not at consecutive host\naddresses), the current contract requires bdrv_get_block_status()\nto clamp *pnum to the limit where host addresses are no longer\nconsecutive, but allowing a NULL file means that *pnum could be\nset to the full length of known-allocated data.\n\nSigned-off-by: Eric Blake <eblake@redhat.com>\n\n---\nv4: only context changes\nv3: rebase to recent changes (qcow2_measure), dropped R-b\nv2: use local variable and final transfer, rather than assignment\nof parameter to local\n[previously in different series]:\nv2: new patch, https://lists.gnu.org/archive/html/qemu-devel/2017-05/msg05645.html\n---\n include/block/block_int.h | 10 ++++++----\n block/io.c | 44 ++++++++++++++++++++++++++++----------------\n block/mirror.c | 3 +--\n block/qcow2.c | 8 ++------\n qemu-img.c | 10 ++++------\n 5 files changed, 41 insertions(+), 34 deletions(-)", "diff": "diff --git a/include/block/block_int.h b/include/block/block_int.h\nindex 55c5d573d4..7f71c585a0 100644\n--- a/include/block/block_int.h\n+++ b/include/block/block_int.h\n@@ -202,10 +202,12 @@ struct BlockDriver {\n int64_t offset, int bytes);\n\n /*\n- * Building block for bdrv_block_status[_above]. The driver should\n- * answer only according to the current layer, and should not\n- * set BDRV_BLOCK_ALLOCATED, but may set BDRV_BLOCK_RAW. See block.h\n- * for the meaning of _DATA, _ZERO, and _OFFSET_VALID.\n+ * Building block for bdrv_block_status[_above] and\n+ * bdrv_is_allocated[_above]. The driver should answer only\n+ * according to the current layer, and should not set\n+ * BDRV_BLOCK_ALLOCATED, but may set BDRV_BLOCK_RAW. See block.h\n+ * for the meaning of _DATA, _ZERO, and _OFFSET_VALID. The block\n+ * layer guarantees non-NULL pnum and file.\n */\n int64_t coroutine_fn (*bdrv_co_get_block_status)(BlockDriverState *bs,\n int64_t sector_num, int nb_sectors, int *pnum,\ndiff --git a/block/io.c b/block/io.c\nindex 8a0cd8835a..f250029395 100644\n--- a/block/io.c\n+++ b/block/io.c\n@@ -695,7 +695,6 @@ int bdrv_make_zero(BdrvChild *child, BdrvRequestFlags flags)\n {\n int64_t target_sectors, ret, nb_sectors, sector_num = 0;\n BlockDriverState *bs = child->bs;\n- BlockDriverState *file;\n int n;\n\n target_sectors = bdrv_nb_sectors(bs);\n@@ -708,7 +707,7 @@ int bdrv_make_zero(BdrvChild *child, BdrvRequestFlags flags)\n if (nb_sectors <= 0) {\n return 0;\n }\n- ret = bdrv_get_block_status(bs, sector_num, nb_sectors, &n, &file);\n+ ret = bdrv_get_block_status(bs, sector_num, nb_sectors, &n, NULL);\n if (ret < 0) {\n error_report(\"error getting block status at sector %\" PRId64 \": %s\",\n sector_num, strerror(-ret));\n@@ -1755,8 +1754,9 @@ int64_t coroutine_fn bdrv_co_get_block_status_from_backing(BlockDriverState *bs,\n * beyond the end of the disk image it will be clamped; if 'pnum' is set to\n * the end of the image, then the returned value will include BDRV_BLOCK_EOF.\n *\n- * If returned value is positive and BDRV_BLOCK_OFFSET_VALID bit is set, 'file'\n- * points to the BDS which the sector range is allocated in.\n+ * If returned value is positive, BDRV_BLOCK_OFFSET_VALID bit is set, and\n+ * 'file' is non-NULL, then '*file' points to the BDS which the sector range\n+ * is allocated in.\n */\n static int64_t coroutine_fn bdrv_co_get_block_status(BlockDriverState *bs,\n int64_t sector_num,\n@@ -1766,15 +1766,22 @@ static int64_t coroutine_fn bdrv_co_get_block_status(BlockDriverState *bs,\n int64_t total_sectors;\n int64_t n;\n int64_t ret, ret2;\n+ BlockDriverState *local_file = NULL;\n\n- *file = NULL;\n+ assert(pnum);\n total_sectors = bdrv_nb_sectors(bs);\n if (total_sectors < 0) {\n+ if (file) {\n+ *file = NULL;\n+ }\n return total_sectors;\n }\n\n if (sector_num >= total_sectors) {\n *pnum = 0;\n+ if (file) {\n+ *file = NULL;\n+ }\n return BDRV_BLOCK_EOF;\n }\n\n@@ -1791,23 +1798,27 @@ static int64_t coroutine_fn bdrv_co_get_block_status(BlockDriverState *bs,\n }\n if (bs->drv->protocol_name) {\n ret |= BDRV_BLOCK_OFFSET_VALID | (sector_num * BDRV_SECTOR_SIZE);\n- *file = bs;\n+ if (file) {\n+ *file = bs;\n+ }\n+ } else if (file) {\n+ *file = NULL;\n }\n return ret;\n }\n\n bdrv_inc_in_flight(bs);\n ret = bs->drv->bdrv_co_get_block_status(bs, sector_num, nb_sectors, pnum,\n- file);\n+ &local_file);\n if (ret < 0) {\n *pnum = 0;\n goto out;\n }\n\n if (ret & BDRV_BLOCK_RAW) {\n- assert(ret & BDRV_BLOCK_OFFSET_VALID && *file);\n- ret = bdrv_co_get_block_status(*file, ret >> BDRV_SECTOR_BITS,\n- *pnum, pnum, file);\n+ assert(ret & BDRV_BLOCK_OFFSET_VALID && local_file);\n+ ret = bdrv_co_get_block_status(local_file, ret >> BDRV_SECTOR_BITS,\n+ *pnum, pnum, &local_file);\n goto out;\n }\n\n@@ -1825,14 +1836,13 @@ static int64_t coroutine_fn bdrv_co_get_block_status(BlockDriverState *bs,\n }\n }\n\n- if (*file && *file != bs &&\n+ if (local_file && local_file != bs &&\n (ret & BDRV_BLOCK_DATA) && !(ret & BDRV_BLOCK_ZERO) &&\n (ret & BDRV_BLOCK_OFFSET_VALID)) {\n- BlockDriverState *file2;\n int file_pnum;\n\n- ret2 = bdrv_co_get_block_status(*file, ret >> BDRV_SECTOR_BITS,\n- *pnum, &file_pnum, &file2);\n+ ret2 = bdrv_co_get_block_status(local_file, ret >> BDRV_SECTOR_BITS,\n+ *pnum, &file_pnum, NULL);\n if (ret2 >= 0) {\n /* Ignore errors. This is just providing extra information, it\n * is useful but not necessary.\n@@ -1854,6 +1864,9 @@ static int64_t coroutine_fn bdrv_co_get_block_status(BlockDriverState *bs,\n }\n\n out:\n+ if (file) {\n+ *file = local_file;\n+ }\n bdrv_dec_in_flight(bs);\n if (ret >= 0 && sector_num + *pnum == total_sectors) {\n ret |= BDRV_BLOCK_EOF;\n@@ -1957,7 +1970,6 @@ int64_t bdrv_get_block_status(BlockDriverState *bs,\n int coroutine_fn bdrv_is_allocated(BlockDriverState *bs, int64_t offset,\n int64_t bytes, int64_t *pnum)\n {\n- BlockDriverState *file;\n int64_t sector_num = offset >> BDRV_SECTOR_BITS;\n int nb_sectors = bytes >> BDRV_SECTOR_BITS;\n int64_t ret;\n@@ -1966,7 +1978,7 @@ int coroutine_fn bdrv_is_allocated(BlockDriverState *bs, int64_t offset,\n assert(QEMU_IS_ALIGNED(offset, BDRV_SECTOR_SIZE));\n assert(QEMU_IS_ALIGNED(bytes, BDRV_SECTOR_SIZE) && bytes < INT_MAX);\n ret = bdrv_get_block_status(bs, sector_num, nb_sectors, &psectors,\n- &file);\n+ NULL);\n if (ret < 0) {\n return ret;\n }\ndiff --git a/block/mirror.c b/block/mirror.c\nindex 5cdaaed7be..032cfe91fa 100644\n--- a/block/mirror.c\n+++ b/block/mirror.c\n@@ -390,7 +390,6 @@ static uint64_t coroutine_fn mirror_iteration(MirrorBlockJob *s)\n int io_sectors;\n unsigned int io_bytes;\n int64_t io_bytes_acct;\n- BlockDriverState *file;\n enum MirrorMethod {\n MIRROR_METHOD_COPY,\n MIRROR_METHOD_ZERO,\n@@ -401,7 +400,7 @@ static uint64_t coroutine_fn mirror_iteration(MirrorBlockJob *s)\n ret = bdrv_get_block_status_above(source, NULL,\n offset >> BDRV_SECTOR_BITS,\n nb_chunks * sectors_per_chunk,\n- &io_sectors, &file);\n+ &io_sectors, NULL);\n io_bytes = io_sectors * BDRV_SECTOR_SIZE;\n if (ret < 0) {\n io_bytes = MIN(nb_chunks * s->granularity, max_io_bytes);\ndiff --git a/block/qcow2.c b/block/qcow2.c\nindex 64dcd98a91..9a7b5cd41f 100644\n--- a/block/qcow2.c\n+++ b/block/qcow2.c\n@@ -2975,7 +2975,6 @@ static bool is_zero_sectors(BlockDriverState *bs, int64_t start,\n uint32_t count)\n {\n int nr;\n- BlockDriverState *file;\n int64_t res;\n\n if (start + count > bs->total_sectors) {\n@@ -2985,8 +2984,7 @@ static bool is_zero_sectors(BlockDriverState *bs, int64_t start,\n if (!count) {\n return true;\n }\n- res = bdrv_get_block_status_above(bs, NULL, start, count,\n- &nr, &file);\n+ res = bdrv_get_block_status_above(bs, NULL, start, count, &nr, NULL);\n return res >= 0 && (res & BDRV_BLOCK_ZERO) && nr == count;\n }\n\n@@ -3654,13 +3652,11 @@ static BlockMeasureInfo *qcow2_measure(QemuOpts *opts, BlockDriverState *in_bs,\n offset += pnum * BDRV_SECTOR_SIZE) {\n int nb_sectors = MIN(ssize - offset,\n BDRV_REQUEST_MAX_BYTES) / BDRV_SECTOR_SIZE;\n- BlockDriverState *file;\n int64_t ret;\n\n ret = bdrv_get_block_status_above(in_bs, NULL,\n offset >> BDRV_SECTOR_BITS,\n- nb_sectors,\n- &pnum, &file);\n+ nb_sectors, &pnum, NULL);\n if (ret < 0) {\n error_setg_errno(&local_err, -ret,\n \"Unable to get block status\");\ndiff --git a/qemu-img.c b/qemu-img.c\nindex df984b11b9..0c12e1c240 100644\n--- a/qemu-img.c\n+++ b/qemu-img.c\n@@ -1374,7 +1374,6 @@ static int img_compare(int argc, char **argv)\n\n for (;;) {\n int64_t status1, status2;\n- BlockDriverState *file;\n\n nb_sectors = sectors_to_process(total_sectors, sector_num);\n if (nb_sectors <= 0) {\n@@ -1382,7 +1381,7 @@ static int img_compare(int argc, char **argv)\n }\n status1 = bdrv_get_block_status_above(bs1, NULL, sector_num,\n total_sectors1 - sector_num,\n- &pnum1, &file);\n+ &pnum1, NULL);\n if (status1 < 0) {\n ret = 3;\n error_report(\"Sector allocation test failed for %s\", filename1);\n@@ -1392,7 +1391,7 @@ static int img_compare(int argc, char **argv)\n\n status2 = bdrv_get_block_status_above(bs2, NULL, sector_num,\n total_sectors2 - sector_num,\n- &pnum2, &file);\n+ &pnum2, NULL);\n if (status2 < 0) {\n ret = 3;\n error_report(\"Sector allocation test failed for %s\", filename2);\n@@ -1598,15 +1597,14 @@ 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- BlockDriverState *file;\n if (s->target_has_backing) {\n ret = bdrv_get_block_status(blk_bs(s->src[src_cur]),\n sector_num - src_cur_offset,\n- n, &n, &file);\n+ n, &n, NULL);\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, &file);\n+ n, &n, NULL);\n }\n if (ret < 0) {\n return ret;\n", "prefixes": [ "v4", "01/23" ] }