From nobody Mon Feb 9 17:24:41 2026 Delivered-To: importer@patchew.org Authentication-Results: mx.zohomail.com; dkim=fail; spf=pass (zohomail.com: domain of gnu.org designates 209.51.188.17 as permitted sender) smtp.mailfrom=qemu-devel-bounces+importer=patchew.org@nongnu.org; dmarc=fail(p=none dis=none) header.from=redhat.com ARC-Seal: i=1; a=rsa-sha256; t=1598971838; cv=none; d=zohomail.com; s=zohoarc; b=Bm+0l5eGsDy9z7pNtXyOMX5soxQ9UURuspTAX92uin8rmzRV+CiDVjw+raDqoVt4dUDptb08JFAo/bhU33lUTAudCOhUv0IYzBRwiK4r9lEeiDjn2p5XYSr4awYOIAMWtAP1dRPdlIm9ZIj09t4ZXQlGr4xRIfKWGZXctftsP/o= ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=zohomail.com; s=zohoarc; t=1598971838; h=Content-Type:Content-Transfer-Encoding:Cc:Date:From:In-Reply-To:List-Subscribe:List-Post:List-Id:List-Archive:List-Help:List-Unsubscribe:MIME-Version:Message-ID:References:Sender:Subject:To; bh=TaoB87eZ5vIpan2tP/K5uD6MYsFfV5Q0Wy9TbkvP+ok=; b=XLcqsBiFvQjinnm+K1Iq+K7JGIOtH40ij/vZ+MjsFcB51wCr/4NIAuoiAL4s2H6aKSXhS9srpgJ5GGhBDa/1KwD0CBUuBUWKdJ/pTutesdtJIEt/nxyuaJP1kANTq9rzx+6+RYf3dvrF8sZJXTImOFRfWqn+q20BDpqYf10bYZw= ARC-Authentication-Results: i=1; mx.zohomail.com; dkim=fail; spf=pass (zohomail.com: domain of gnu.org designates 209.51.188.17 as permitted sender) smtp.mailfrom=qemu-devel-bounces+importer=patchew.org@nongnu.org; dmarc=fail header.from= (p=none dis=none) header.from= Return-Path: Received: from lists.gnu.org (lists.gnu.org [209.51.188.17]) by mx.zohomail.com with SMTPS id 1598971838437753.4882100705763; Tue, 1 Sep 2020 07:50:38 -0700 (PDT) Received: from localhost ([::1]:56992 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1kD7cL-0004Ea-M1 for importer@patchew.org; Tue, 01 Sep 2020 10:50:37 -0400 Received: from eggs.gnu.org ([2001:470:142:3::10]:33998) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1kD7NH-00088v-9M for qemu-devel@nongnu.org; Tue, 01 Sep 2020 10:35:03 -0400 Received: from us-smtp-delivery-1.mimecast.com ([207.211.31.120]:24208 helo=us-smtp-1.mimecast.com) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_CBC_SHA1:256) (Exim 4.90_1) (envelope-from ) id 1kD7NF-00077z-As for qemu-devel@nongnu.org; Tue, 01 Sep 2020 10:35:02 -0400 Received: from mimecast-mx01.redhat.com (mimecast-mx01.redhat.com [209.132.183.4]) (Using TLS) by relay.mimecast.com with ESMTP id us-mta-313-rrlxhX7DPOiSKYWAvOw_Dg-1; Tue, 01 Sep 2020 10:34:59 -0400 Received: from smtp.corp.redhat.com (int-mx01.intmail.prod.int.phx2.redhat.com [10.5.11.11]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id BACCD8015DB; Tue, 1 Sep 2020 14:34:57 +0000 (UTC) Received: from localhost (ovpn-113-83.ams2.redhat.com [10.36.113.83]) by smtp.corp.redhat.com (Postfix) with ESMTPS id 5A86B7DA24; Tue, 1 Sep 2020 14:34:57 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1598970900; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=TaoB87eZ5vIpan2tP/K5uD6MYsFfV5Q0Wy9TbkvP+ok=; b=OKc1EnGgw1folYknbMVFWc7sc5w7gDL/CcjD3woXyj7S/O/4nrXb/+5szO78f+QpWBJvud 2eiQlMtQQmvOdQrEmbhy7Ml4QmpGhFJ9UiLSfjGNSC+DP4rjc/SGrXMWBnaMIWfz/oTI63 RllFsFA0DO9OIUYX6hKuX/8hJkq1rpc= X-MC-Unique: rrlxhX7DPOiSKYWAvOw_Dg-1 From: Max Reitz To: qemu-block@nongnu.org Subject: [PATCH v8 13/43] block: Use CAFs when working with backing chains Date: Tue, 1 Sep 2020 16:33:54 +0200 Message-Id: <20200901143424.884735-14-mreitz@redhat.com> In-Reply-To: <20200901143424.884735-1-mreitz@redhat.com> References: <20200901143424.884735-1-mreitz@redhat.com> MIME-Version: 1.0 X-Scanned-By: MIMEDefang 2.79 on 10.5.11.11 Authentication-Results: relay.mimecast.com; auth=pass smtp.auth=CUSA124A263 smtp.mailfrom=mreitz@redhat.com X-Mimecast-Spam-Score: 0.001 X-Mimecast-Originator: redhat.com Content-Transfer-Encoding: quoted-printable Received-SPF: pass (zohomail.com: domain of gnu.org designates 209.51.188.17 as permitted sender) client-ip=209.51.188.17; envelope-from=qemu-devel-bounces+importer=patchew.org@nongnu.org; helo=lists.gnu.org; Received-SPF: pass client-ip=207.211.31.120; envelope-from=mreitz@redhat.com; helo=us-smtp-1.mimecast.com X-detected-operating-system: by eggs.gnu.org: First seen = 2020/09/01 00:57:59 X-ACL-Warn: Detected OS = Linux 2.2.x-3.x [generic] [fuzzy] X-Spam_score_int: -20 X-Spam_score: -2.1 X-Spam_bar: -- X-Spam_report: (-2.1 / 5.0 requ) BAYES_00=-1.9, DKIMWL_WL_HIGH=-0.001, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, DKIM_VALID_EF=-0.1, RCVD_IN_DNSWL_NONE=-0.0001, RCVD_IN_MSPIKE_H2=-0.001, SPF_HELO_NONE=0.001, SPF_PASS=-0.001 autolearn=ham autolearn_force=no X-Spam_action: no action 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 , Andrey Shinkevich , Vladimir Sementsov-Ogievskiy , qemu-devel@nongnu.org, Max Reitz Errors-To: qemu-devel-bounces+importer=patchew.org@nongnu.org Sender: "Qemu-devel" X-ZohoMail-DKIM: fail (Header signature does not verify) Content-Type: text/plain; charset="utf-8" Use child access functions when iterating through backing chains so filters do not break the chain. In addition, bdrv_find_overlay() will now always return the actual overlay; that is, it will never return a filter node but only one with a COW backing file (there may be filter nodes between that node and @bs). Signed-off-by: Max Reitz --- block.c | 44 ++++++++++++++++++++++++++++++-------------- 1 file changed, 30 insertions(+), 14 deletions(-) diff --git a/block.c b/block.c index 887c125400..96bf8672f1 100644 --- a/block.c +++ b/block.c @@ -4745,9 +4745,9 @@ int bdrv_change_backing_file(BlockDriverState *bs, co= nst char *backing_file, } =20 /* - * Finds the image layer in the chain that has 'bs' as its backing file. - * - * active is the current topmost image. + * Finds the first non-filter node above bs in the chain between + * active and bs. The returned node is either an immediate parent of + * bs, or there are only filter nodes between the two. * * Returns NULL if bs is not found in active's image chain, * or if active =3D=3D bs. @@ -4757,11 +4757,18 @@ int bdrv_change_backing_file(BlockDriverState *bs, = const char *backing_file, BlockDriverState *bdrv_find_overlay(BlockDriverState *active, BlockDriverState *bs) { - while (active && bs !=3D backing_bs(active)) { - active =3D backing_bs(active); + bs =3D bdrv_skip_filters(bs); + active =3D bdrv_skip_filters(active); + + while (active) { + BlockDriverState *next =3D bdrv_backing_chain_next(active); + if (bs =3D=3D next) { + return active; + } + active =3D next; } =20 - return active; + return NULL; } =20 /* Given a BDS, searches for the base layer. */ @@ -4913,9 +4920,7 @@ int bdrv_drop_intermediate(BlockDriverState *top, Blo= ckDriverState *base, * other intermediate nodes have been dropped. * If 'top' is an implicit node (e.g. "commit_top") we should skip * it because no one inherits from it. We use explicit_top for that. */ - while (explicit_top && explicit_top->implicit) { - explicit_top =3D backing_bs(explicit_top); - } + explicit_top =3D bdrv_skip_implicit_filters(explicit_top); update_inherits_from =3D bdrv_inherits_from_recursive(base, explicit_t= op); =20 /* success - we can delete the intermediate states, and link top->base= */ @@ -5372,7 +5377,7 @@ BlockDriverState *bdrv_lookup_bs(const char *device, bool bdrv_chain_contains(BlockDriverState *top, BlockDriverState *base) { while (top && top !=3D base) { - top =3D backing_bs(top); + top =3D bdrv_filter_or_cow_bs(top); } =20 return top !=3D NULL; @@ -5613,6 +5618,7 @@ BlockDriverState *bdrv_find_backing_image(BlockDriver= State *bs, int is_protocol =3D 0; BlockDriverState *curr_bs =3D NULL; BlockDriverState *retval =3D NULL; + BlockDriverState *bs_below; =20 if (!bs || !bs->drv || !backing_file) { return NULL; @@ -5623,7 +5629,17 @@ BlockDriverState *bdrv_find_backing_image(BlockDrive= rState *bs, =20 is_protocol =3D path_has_protocol(backing_file); =20 - for (curr_bs =3D bs; curr_bs->backing; curr_bs =3D curr_bs->backing->b= s) { + /* + * Being largely a legacy function, skip any filters here + * (because filters do not have normal filenames, so they cannot + * match anyway; and allowing json:{} filenames is a bit out of + * scope). + */ + for (curr_bs =3D bdrv_skip_filters(bs); + bdrv_cow_child(curr_bs) !=3D NULL; + curr_bs =3D bs_below) + { + 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 */ @@ -5631,7 +5647,7 @@ BlockDriverState *bdrv_find_backing_image(BlockDriver= State *bs, char *backing_file_full_ret; =20 if (strcmp(backing_file, curr_bs->backing_file) =3D=3D 0) { - retval =3D curr_bs->backing->bs; + retval =3D bs_below; break; } /* Also check against the full backing filename for the image = */ @@ -5641,7 +5657,7 @@ BlockDriverState *bdrv_find_backing_image(BlockDriver= State *bs, bool equal =3D strcmp(backing_file, backing_file_full_ret)= =3D=3D 0; g_free(backing_file_full_ret); if (equal) { - retval =3D curr_bs->backing->bs; + retval =3D bs_below; break; } } @@ -5667,7 +5683,7 @@ BlockDriverState *bdrv_find_backing_image(BlockDriver= State *bs, g_free(filename_tmp); =20 if (strcmp(backing_file_full, filename_full) =3D=3D 0) { - retval =3D curr_bs->backing->bs; + retval =3D bs_below; break; } } --=20 2.26.2