From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-6.8 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 31A57C31E46 for ; Wed, 12 Jun 2019 22:50:54 +0000 (UTC) Received: from lists.gnu.org (lists.gnu.org [209.51.188.17]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id EBED320B7C for ; Wed, 12 Jun 2019 22:50:53 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org EBED320B7C Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=redhat.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Received: from localhost ([::1]:35730 helo=lists.gnu.org) by lists.gnu.org with esmtp (Exim 4.86_2) (envelope-from ) id 1hbC4z-0005Q6-7m for qemu-devel@archiver.kernel.org; Wed, 12 Jun 2019 18:50:53 -0400 Received: from eggs.gnu.org ([2001:470:142:3::10]:46474) by lists.gnu.org with esmtp (Exim 4.86_2) (envelope-from ) id 1hbBTH-0000YL-Ax for qemu-devel@nongnu.org; Wed, 12 Jun 2019 18:11:57 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1hbBTF-0008RJ-0x for qemu-devel@nongnu.org; Wed, 12 Jun 2019 18:11:55 -0400 Received: from mx1.redhat.com ([209.132.183.28]:34878) by eggs.gnu.org with esmtps (TLS1.0:DHE_RSA_AES_256_CBC_SHA1:32) (Exim 4.71) (envelope-from ) id 1hbBT6-0008KT-L6; Wed, 12 Jun 2019 18:11:46 -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 CB769A3B69; Wed, 12 Jun 2019 22:11:42 +0000 (UTC) Received: from localhost (unknown [10.40.205.72]) by smtp.corp.redhat.com (Postfix) with ESMTPS id 2E9795C236; Wed, 12 Jun 2019 22:11:41 +0000 (UTC) From: Max Reitz To: qemu-block@nongnu.org Date: Thu, 13 Jun 2019 00:09:59 +0200 Message-Id: <20190612221004.2317-38-mreitz@redhat.com> In-Reply-To: <20190612221004.2317-1-mreitz@redhat.com> References: <20190612221004.2317-1-mreitz@redhat.com> MIME-Version: 1.0 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 [10.5.110.30]); Wed, 12 Jun 2019 22:11:42 +0000 (UTC) Content-Transfer-Encoding: quoted-printable X-detected-operating-system: by eggs.gnu.org: GNU/Linux 2.2.x-3.x [generic] X-Received-From: 209.132.183.28 Subject: [Qemu-devel] [PATCH v5 37/42] block: Leave BDS.backing_file constant X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.23 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Kevin Wolf , Vladimir Sementsov-Ogievskiy , qemu-devel@nongnu.org, Max Reitz Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: "Qemu-devel" Parts of the block layer treat BDS.backing_file as if it were whatever the image header says (i.e., if it is a relative path, it is relative to the overlay), other parts treat it like a cache for bs->backing->bs->filename (relative paths are relative to the CWD). Considering bs->backing->bs->filename exists, let us make it mean the former. Among other things, this now allows the user to specify a base when using qemu-img to commit an image file in a directory that is not the CWD (assuming, everything uses relative filenames). Before this patch: $ ./qemu-img create -f qcow2 foo/bot.qcow2 1M $ ./qemu-img create -f qcow2 -b bot.qcow2 foo/mid.qcow2 $ ./qemu-img create -f qcow2 -b mid.qcow2 foo/top.qcow2 $ ./qemu-img commit -b mid.qcow2 foo/top.qcow2 qemu-img: Did not find 'mid.qcow2' in the backing chain of 'foo/top.qcow2= ' $ ./qemu-img commit -b foo/mid.qcow2 foo/top.qcow2 qemu-img: Did not find 'foo/mid.qcow2' in the backing chain of 'foo/top.q= cow2' $ ./qemu-img commit -b $PWD/foo/mid.qcow2 foo/top.qcow2 qemu-img: Did not find '[...]/foo/mid.qcow2' in the backing chain of 'foo= /top.qcow2' After this patch: $ ./qemu-img commit -b mid.qcow2 foo/top.qcow2 Image committed. $ ./qemu-img commit -b foo/mid.qcow2 foo/top.qcow2 qemu-img: Did not find 'foo/mid.qcow2' in the backing chain of 'foo/top.q= cow2' $ ./qemu-img commit -b $PWD/foo/mid.qcow2 foo/top.qcow2 Image committed. With this change, bdrv_find_backing_image() must look at whether the user has overridden a BDS's backing file. If so, it can no longer use bs->backing_file, but must instead compare the given filename against the backing node's filename directly. Note that this changes the QAPI output for a node's backing_file. We had very inconsistent output there (sometimes what the image header said, sometimes the actual filename of the backing image). This inconsistent output was effectively useless, so we have to decide one way or the other. Considering that bs->backing_file usually at runtime contained the path to the image relative to qemu's CWD (or absolute), this patch changes QAPI's backing_file to always report the bs->backing->bs->filename from now on. If you want to receive the image header information, you have to refer to full-backing-filename. This necessitates a change to iotest 228. The interesting information it really wanted is the image header, and it can get that now, but it has to use full-backing-filename instead of backing_file. Because of this patch's changes to bs->backing_file's behavior, we also need some reference output changes. Along with the changes to bs->backing_file, stop updating BDS.backing_format in bdrv_backing_attach() as well. This necessitates a change to the reference output of iotest 191. iotest 245 changes in behavior: With the backing node no longer overriding the parent node's backing_file string, you can now omit the @backing option when reopening a node with neither a default nor a current backing file even if it used to have a backing node at some point. Signed-off-by: Max Reitz --- include/block/block_int.h | 19 ++++++++++++++----- block.c | 35 ++++++++++++++++++++++++++++------- block/qapi.c | 7 ++++--- tests/qemu-iotests/191.out | 1 - tests/qemu-iotests/228 | 6 +++--- tests/qemu-iotests/228.out | 6 +++--- tests/qemu-iotests/245 | 4 +++- 7 files changed, 55 insertions(+), 23 deletions(-) diff --git a/include/block/block_int.h b/include/block/block_int.h index 431fa38ea0..02b55cff91 100644 --- a/include/block/block_int.h +++ b/include/block/block_int.h @@ -777,11 +777,20 @@ struct BlockDriverState { bool walking_aio_notifiers; /* to make removal during iteration safe= */ =20 char filename[PATH_MAX]; - char backing_file[PATH_MAX]; /* if non zero, the image is a diff of - this file image */ - /* The backing filename indicated by the image header; if we ever - * open this file, then this is replaced by the resulting BDS's - * filename (i.e. after a bdrv_refresh_filename() run). */ + /* + * If not empty, this image is a diff in relation to backing_file. + * Note that this is the name given in the image header and + * therefore may or may not be equal to .backing->bs->filename. + * If this field contains a relative path, it is to be resolved + * relatively to the overlay's location. + */ + char backing_file[PATH_MAX]; + /* + * The backing filename indicated by the image header. Contrary + * to backing_file, if we ever open this file, auto_backing_file + * is replaced by the resulting BDS's filename (i.e. after a + * bdrv_refresh_filename() run). + */ char auto_backing_file[PATH_MAX]; char backing_format[16]; /* if non-zero and backing_file exists */ =20 diff --git a/block.c b/block.c index e129869a7e..a962e346ab 100644 --- a/block.c +++ b/block.c @@ -78,6 +78,8 @@ static BlockDriverState *bdrv_open_inherit(const char *= filename, const BdrvChildRole *child_ro= le, Error **errp); =20 +static bool bdrv_backing_overridden(BlockDriverState *bs); + /* If non-zero, use only whitelisted block drivers */ static int use_bdrv_whitelist; =20 @@ -1064,10 +1066,6 @@ static void bdrv_backing_attach(BdrvChild *c) bdrv_refresh_filename(backing_hd); =20 parent->open_flags &=3D ~BDRV_O_NO_BACKING; - pstrcpy(parent->backing_file, sizeof(parent->backing_file), - backing_hd->filename); - pstrcpy(parent->backing_format, sizeof(parent->backing_format), - backing_hd->drv ? backing_hd->drv->format_name : ""); =20 bdrv_op_block_all(backing_hd, parent->backing_blocker); /* Otherwise we won't be able to commit or stream */ @@ -5177,6 +5175,7 @@ BlockDriverState *bdrv_find_backing_image(BlockDriv= erState *bs, char *backing_file_full =3D NULL; char *filename_tmp =3D NULL; int is_protocol =3D 0; + bool filenames_refreshed =3D false; BlockDriverState *curr_bs =3D NULL; BlockDriverState *retval =3D NULL; =20 @@ -5201,9 +5200,31 @@ BlockDriverState *bdrv_find_backing_image(BlockDri= verState *bs, { BlockDriverState *bs_below =3D bdrv_backing_chain_next(curr_bs); =20 - /* If either of the filename paths is actually a protocol, then - * compare unmodified paths; otherwise make paths relative */ - if (is_protocol || path_has_protocol(curr_bs->backing_file)) { + if (bdrv_backing_overridden(curr_bs)) { + /* + * If the backing file was overridden, we can only compare + * directly against the backing node's filename. + */ + + if (!filenames_refreshed) { + /* + * This will automatically refresh all of the + * filenames in the rest of the backing chain, so we + * only need to do this once. + */ + bdrv_refresh_filename(bs_below); + filenames_refreshed =3D true; + } + + if (strcmp(backing_file, bs_below->filename) =3D=3D 0) { + retval =3D bs_below; + break; + } + } else if (is_protocol || path_has_protocol(curr_bs->backing_fil= e)) { + /* + * If either of the filename paths is actually a protocol, t= hen + * compare unmodified paths; otherwise make paths relative. + */ char *backing_file_full_ret; =20 if (strcmp(backing_file, curr_bs->backing_file) =3D=3D 0) { diff --git a/block/qapi.c b/block/qapi.c index 1fd2937abc..3586c09516 100644 --- a/block/qapi.c +++ b/block/qapi.c @@ -44,7 +44,7 @@ BlockDeviceInfo *bdrv_block_device_info(BlockBackend *b= lk, BlockDriverState *bs, Error **er= rp) { ImageInfo **p_image_info; - BlockDriverState *bs0; + BlockDriverState *bs0, *backing; BlockDeviceInfo *info; =20 if (!bs->drv) { @@ -73,9 +73,10 @@ BlockDeviceInfo *bdrv_block_device_info(BlockBackend *= blk, info->node_name =3D g_strdup(bs->node_name); } =20 - if (bs->backing_file[0]) { + backing =3D bdrv_filtered_cow_bs(bs); + if (backing) { info->has_backing_file =3D true; - info->backing_file =3D g_strdup(bs->backing_file); + info->backing_file =3D g_strdup(backing->filename); } =20 info->detect_zeroes =3D bs->detect_zeroes; diff --git a/tests/qemu-iotests/191.out b/tests/qemu-iotests/191.out index 3fc92bb56e..0b3c216b0c 100644 --- a/tests/qemu-iotests/191.out +++ b/tests/qemu-iotests/191.out @@ -605,7 +605,6 @@ wrote 65536/65536 bytes at offset 1048576 "backing-filename": "TEST_DIR/t.IMGFMT.base", "dirty-flag": false }, - "backing-filename-format": "IMGFMT", "virtual-size": 67108864, "filename": "TEST_DIR/t.IMGFMT.ovl3", "cluster-size": 65536, diff --git a/tests/qemu-iotests/228 b/tests/qemu-iotests/228 index 9a50afd205..a1f3187212 100755 --- a/tests/qemu-iotests/228 +++ b/tests/qemu-iotests/228 @@ -34,7 +34,7 @@ def log_node_info(node): =20 log('bs->filename: ' + node['image']['filename'], filters=3D[filter_testfiles, filter_imgfmt]) - log('bs->backing_file: ' + node['backing_file'], + log('bs->backing_file: ' + node['image']['full-backing-filename'], filters=3D[filter_testfiles, filter_imgfmt]) =20 if 'backing-image' in node['image']: @@ -70,8 +70,8 @@ with iotests.FilePath('base.img') as base_img_path, \ }, filters=3D[filter_qmp_testfiles, filter_qmp_imgfmt]) =20 - # Filename should be plain, and the backing filename should not - # contain the "file:" prefix + # Filename should be plain, and the backing node filename should + # not contain the "file:" prefix log_node_info(vm.node_info('node0')) =20 vm.qmp_log('blockdev-del', node_name=3D'node0') diff --git a/tests/qemu-iotests/228.out b/tests/qemu-iotests/228.out index 4217df24fe..8c82009abe 100644 --- a/tests/qemu-iotests/228.out +++ b/tests/qemu-iotests/228.out @@ -4,7 +4,7 @@ {"return": {}} =20 bs->filename: TEST_DIR/PID-top.img -bs->backing_file: TEST_DIR/PID-base.img +bs->backing_file: file:TEST_DIR/PID-base.img bs->backing->bs->filename: TEST_DIR/PID-base.img =20 {"execute": "blockdev-del", "arguments": {"node-name": "node0"}} @@ -41,7 +41,7 @@ bs->backing->bs->filename: TEST_DIR/PID-base.img {"return": {}} =20 bs->filename: TEST_DIR/PID-top.img -bs->backing_file: TEST_DIR/PID-base.img +bs->backing_file: file:TEST_DIR/PID-base.img bs->backing->bs->filename: TEST_DIR/PID-base.img =20 {"execute": "blockdev-del", "arguments": {"node-name": "node0"}} @@ -55,7 +55,7 @@ bs->backing->bs->filename: TEST_DIR/PID-base.img {"return": {}} =20 bs->filename: json:{"backing": {"driver": "null-co"}, "driver": "IMGFMT"= , "file": {"driver": "file", "filename": "TEST_DIR/PID-top.img"}} -bs->backing_file: null-co:// +bs->backing_file: TEST_DIR/PID-base.img bs->backing->bs->filename: null-co:// =20 {"execute": "blockdev-del", "arguments": {"node-name": "node0"}} diff --git a/tests/qemu-iotests/245 b/tests/qemu-iotests/245 index 349b94aace..80c3e1b92d 100644 --- a/tests/qemu-iotests/245 +++ b/tests/qemu-iotests/245 @@ -722,7 +722,9 @@ class TestBlockdevReopen(iotests.QMPTestCase): =20 # Detach hd2 from hd0. self.reopen(opts, {'backing': None}) - self.reopen(opts, {}, "backing is missing for 'hd0'") + + # Without a backing file, we can omit 'backing' again + self.reopen(opts) =20 # Remove both hd0 and hd2 result =3D self.vm.qmp('blockdev-del', conv_keys =3D True, node_= name =3D 'hd0') --=20 2.21.0