From patchwork Mon Jul 3 22:14:43 2017 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Eric Blake X-Patchwork-Id: 783669 Return-Path: X-Original-To: incoming@patchwork.ozlabs.org Delivered-To: patchwork-incoming@bilbo.ozlabs.org Received: from lists.gnu.org (lists.gnu.org [IPv6:2001:4830:134:3::11]) (using TLSv1 with cipher AES256-SHA (256/256 bits)) (No client certificate requested) by ozlabs.org (Postfix) with ESMTPS id 3x1hPG5bJVz9s06 for ; Tue, 4 Jul 2017 08:18:58 +1000 (AEST) Received: from localhost ([::1]:37489 helo=lists.gnu.org) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1dS9gG-0001Nr-9G for incoming@patchwork.ozlabs.org; Mon, 03 Jul 2017 18:18:56 -0400 Received: from eggs.gnu.org ([2001:4830:134:3::10]:55831) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1dS9cp-0007X2-QC for qemu-devel@nongnu.org; Mon, 03 Jul 2017 18:15:25 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1dS9cn-0004Ts-Rl for qemu-devel@nongnu.org; Mon, 03 Jul 2017 18:15:23 -0400 Received: from mx1.redhat.com ([209.132.183.28]:57596) by eggs.gnu.org with esmtps (TLS1.0:DHE_RSA_AES_256_CBC_SHA1:32) (Exim 4.71) (envelope-from ) id 1dS9ci-0004Ny-Lt; Mon, 03 Jul 2017 18:15:16 -0400 Received: from smtp.corp.redhat.com (int-mx06.intmail.prod.int.phx2.redhat.com [10.5.11.16]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mx1.redhat.com (Postfix) with ESMTPS id 8F65AA0218; Mon, 3 Jul 2017 22:15:15 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mx1.redhat.com 8F65AA0218 Authentication-Results: ext-mx02.extmail.prod.ext.phx2.redhat.com; dmarc=none (p=none dis=none) header.from=redhat.com Authentication-Results: ext-mx02.extmail.prod.ext.phx2.redhat.com; spf=pass smtp.mailfrom=eblake@redhat.com DKIM-Filter: OpenDKIM Filter v2.11.0 mx1.redhat.com 8F65AA0218 Received: from red.redhat.com (ovpn-120-36.rdu2.redhat.com [10.10.120.36]) by smtp.corp.redhat.com (Postfix) with ESMTP id 11AE46A308; Mon, 3 Jul 2017 22:15:13 +0000 (UTC) From: Eric Blake To: qemu-devel@nongnu.org Date: Mon, 3 Jul 2017 17:14:43 -0500 Message-Id: <20170703221456.30817-3-eblake@redhat.com> In-Reply-To: <20170703221456.30817-1-eblake@redhat.com> References: <20170703221456.30817-1-eblake@redhat.com> X-Scanned-By: MIMEDefang 2.79 on 10.5.11.16 X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.5.16 (mx1.redhat.com [10.5.110.26]); Mon, 03 Jul 2017 22:15:15 +0000 (UTC) X-detected-operating-system: by eggs.gnu.org: GNU/Linux 2.2.x-3.x [generic] [fuzzy] X-Received-From: 209.132.183.28 Subject: [Qemu-devel] [PATCH v2 02/15] block: Allow NULL file for bdrv_get_block_status() X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.21 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: kwolf@redhat.com, Fam Zheng , qemu-block@nongnu.org, el13635@mail.ntua.gr, Jeff Cody , Max Reitz , Stefan Hajnoczi , jsnow@redhat.com Errors-To: qemu-devel-bounces+incoming=patchwork.ozlabs.org@nongnu.org Sender: "Qemu-devel" Not all callers care about which BDS owns the mapping for a given range of the file. This patch merely simplifies the callers by consolidating the logic in the common call point, while guaranteeing a non-NULL file to all the driver callbacks, for no semantic change. The only caller that does not care about pnum is bdrv_is_allocated, as invoked by vvfat; we can likewise add assertions that the rest of the stack does not have to worry about a NULL pnum. Furthermore, this will also set the stage for a future cleanup: when a caller does not care about which BDS owns an offset, it would be nice to allow the driver to optimize things to not have to return BDRV_BLOCK_OFFSET_VALID in the first place. In the case of fragmented allocation (for example, it's fairly easy to create a qcow2 image where consecutive guest addresses are not at consecutive host addresses), the current contract requires bdrv_get_block_status() to clamp *pnum to the limit where host addresses are no longer consecutive, but allowing a NULL file means that *pnum could be set to the full length of known-allocated data. Signed-off-by: Eric Blake Reviewed-by: Fam Zheng --- v2: use local variable and final transfer, rather than assignment of parameter to local [previously in different series]: v2: new patch, https://lists.gnu.org/archive/html/qemu-devel/2017-05/msg05645.html --- include/block/block_int.h | 10 ++++++---- block/io.c | 44 ++++++++++++++++++++++++++++---------------- block/mirror.c | 3 +-- block/qcow2.c | 4 +--- qemu-img.c | 10 ++++------ 5 files changed, 40 insertions(+), 31 deletions(-) diff --git a/include/block/block_int.h b/include/block/block_int.h index 724799c..ffa22c7 100644 --- a/include/block/block_int.h +++ b/include/block/block_int.h @@ -168,10 +168,12 @@ 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 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/block/io.c b/block/io.c index 8c67ba8..6358d07 100644 --- a/block/io.c +++ b/block/io.c @@ -671,7 +671,6 @@ int bdrv_make_zero(BdrvChild *child, BdrvRequestFlags flags) { int64_t target_sectors, ret, nb_sectors, sector_num = 0; BlockDriverState *bs = child->bs; - BlockDriverState *file; int n; target_sectors = bdrv_nb_sectors(bs); @@ -684,7 +683,7 @@ int bdrv_make_zero(BdrvChild *child, BdrvRequestFlags flags) if (nb_sectors <= 0) { return 0; } - ret = bdrv_get_block_status(bs, sector_num, nb_sectors, &n, &file); + ret = bdrv_get_block_status(bs, sector_num, nb_sectors, &n, NULL); if (ret < 0) { error_report("error getting block status at sector %" PRId64 ": %s", sector_num, strerror(-ret)); @@ -1729,8 +1728,9 @@ int64_t coroutine_fn bdrv_co_get_block_status_from_backing(BlockDriverState *bs, * 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. + * If returned value is positive, BDRV_BLOCK_OFFSET_VALID bit is set, and + * 'file' is non-NULL, then '*file' points to the BDS which the sector range + * is allocated in. */ static int64_t coroutine_fn bdrv_co_get_block_status(BlockDriverState *bs, int64_t sector_num, @@ -1740,15 +1740,22 @@ static int64_t coroutine_fn bdrv_co_get_block_status(BlockDriverState *bs, int64_t total_sectors; int64_t n; int64_t ret, ret2; + BlockDriverState *local_file = NULL; - *file = NULL; + assert(pnum); total_sectors = bdrv_nb_sectors(bs); if (total_sectors < 0) { + if (file) { + *file = NULL; + } return total_sectors; } if (sector_num >= total_sectors) { *pnum = 0; + if (file) { + *file = NULL; + } return BDRV_BLOCK_EOF; } @@ -1765,23 +1772,27 @@ static int64_t coroutine_fn bdrv_co_get_block_status(BlockDriverState *bs, } if (bs->drv->protocol_name) { ret |= BDRV_BLOCK_OFFSET_VALID | (sector_num * BDRV_SECTOR_SIZE); - *file = bs; + if (file) { + *file = bs; + } + } else if (file) { + *file = NULL; } return ret; } bdrv_inc_in_flight(bs); ret = bs->drv->bdrv_co_get_block_status(bs, sector_num, nb_sectors, pnum, - file); + &local_file); if (ret < 0) { *pnum = 0; goto out; } 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_get_block_status(local_file, ret >> BDRV_SECTOR_BITS, + *pnum, pnum, &local_file); goto out; } @@ -1799,14 +1810,13 @@ static int64_t coroutine_fn bdrv_co_get_block_status(BlockDriverState *bs, } } - if (*file && *file != bs && + if (local_file && local_file != bs && (ret & BDRV_BLOCK_DATA) && !(ret & BDRV_BLOCK_ZERO) && (ret & BDRV_BLOCK_OFFSET_VALID)) { - BlockDriverState *file2; int file_pnum; - ret2 = bdrv_co_get_block_status(*file, ret >> BDRV_SECTOR_BITS, - *pnum, &file_pnum, &file2); + ret2 = bdrv_co_get_block_status(local_file, ret >> BDRV_SECTOR_BITS, + *pnum, &file_pnum, NULL); if (ret2 >= 0) { /* Ignore errors. This is just providing extra information, it * is useful but not necessary. @@ -1828,6 +1838,9 @@ static int64_t coroutine_fn bdrv_co_get_block_status(BlockDriverState *bs, } out: + if (file) { + *file = local_file; + } bdrv_dec_in_flight(bs); if (ret >= 0 && sector_num + *pnum == total_sectors) { ret |= BDRV_BLOCK_EOF; @@ -1931,7 +1944,6 @@ int64_t bdrv_get_block_status(BlockDriverState *bs, 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; @@ -1941,7 +1953,7 @@ int coroutine_fn bdrv_is_allocated(BlockDriverState *bs, int64_t offset, assert(QEMU_IS_ALIGNED(bytes, BDRV_SECTOR_SIZE) && bytes < INT_MAX * BDRV_SECTOR_SIZE); ret = bdrv_get_block_status(bs, sector_num, nb_sectors, &psectors, - &file); + NULL); if (ret < 0) { return ret; } diff --git a/block/mirror.c b/block/mirror.c index 4e883bc..21758a8 100644 --- a/block/mirror.c +++ b/block/mirror.c @@ -391,7 +391,6 @@ static uint64_t coroutine_fn mirror_iteration(MirrorBlockJob *s) int io_sectors; unsigned int io_bytes; int64_t io_bytes_acct; - BlockDriverState *file; enum MirrorMethod { MIRROR_METHOD_COPY, MIRROR_METHOD_ZERO, @@ -402,7 +401,7 @@ static uint64_t coroutine_fn mirror_iteration(MirrorBlockJob *s) ret = bdrv_get_block_status_above(source, NULL, offset >> BDRV_SECTOR_BITS, nb_chunks * sectors_per_chunk, - &io_sectors, &file); + &io_sectors, NULL); io_bytes = io_sectors * BDRV_SECTOR_SIZE; if (ret < 0) { io_bytes = MIN(nb_chunks * s->granularity, max_io_bytes); diff --git a/block/qcow2.c b/block/qcow2.c index 9d3c70e..d75f248 100644 --- a/block/qcow2.c +++ b/block/qcow2.c @@ -2909,7 +2909,6 @@ static bool is_zero_sectors(BlockDriverState *bs, int64_t start, uint32_t count) { int nr; - BlockDriverState *file; int64_t res; if (start + count > bs->total_sectors) { @@ -2919,8 +2918,7 @@ static bool is_zero_sectors(BlockDriverState *bs, int64_t start, if (!count) { return true; } - res = bdrv_get_block_status_above(bs, NULL, start, count, - &nr, &file); + res = bdrv_get_block_status_above(bs, NULL, start, count, &nr, NULL); return res >= 0 && (res & BDRV_BLOCK_ZERO) && nr == count; } diff --git a/qemu-img.c b/qemu-img.c index 8def1e8..daba954 100644 --- a/qemu-img.c +++ b/qemu-img.c @@ -1373,7 +1373,6 @@ static int img_compare(int argc, char **argv) for (;;) { int64_t status1, status2; - BlockDriverState *file; nb_sectors = sectors_to_process(total_sectors, sector_num); if (nb_sectors <= 0) { @@ -1381,7 +1380,7 @@ static int img_compare(int argc, char **argv) } status1 = bdrv_get_block_status_above(bs1, NULL, sector_num, total_sectors1 - sector_num, - &pnum1, &file); + &pnum1, NULL); if (status1 < 0) { ret = 3; error_report("Sector allocation test failed for %s", filename1); @@ -1391,7 +1390,7 @@ static int img_compare(int argc, char **argv) status2 = bdrv_get_block_status_above(bs2, NULL, sector_num, total_sectors2 - sector_num, - &pnum2, &file); + &pnum2, NULL); if (status2 < 0) { ret = 3; error_report("Sector allocation test failed for %s", filename2); @@ -1594,15 +1593,14 @@ 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; if (s->target_has_backing) { ret = bdrv_get_block_status(blk_bs(s->src[src_cur]), sector_num - src_cur_offset, - n, &n, &file); + n, &n, NULL); } else { ret = bdrv_get_block_status_above(blk_bs(s->src[src_cur]), NULL, sector_num - src_cur_offset, - n, &n, &file); + n, &n, NULL); } if (ret < 0) { return ret;