From patchwork Wed May 13 09:50:49 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Andrey Shinkevich X-Patchwork-Id: 1289128 Return-Path: X-Original-To: incoming@patchwork.ozlabs.org Delivered-To: patchwork-incoming@bilbo.ozlabs.org Authentication-Results: ozlabs.org; spf=pass (sender SPF authorized) smtp.mailfrom=nongnu.org (client-ip=209.51.188.17; helo=lists.gnu.org; envelope-from=qemu-devel-bounces+incoming=patchwork.ozlabs.org@nongnu.org; receiver=) Authentication-Results: ozlabs.org; dmarc=fail (p=none dis=none) header.from=virtuozzo.com 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 ozlabs.org (Postfix) with ESMTPS id 49MVPC3QQvz9sSf for ; Wed, 13 May 2020 19:53:51 +1000 (AEST) Received: from localhost ([::1]:48750 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1jYo5E-0002AY-W4 for incoming@patchwork.ozlabs.org; Wed, 13 May 2020 05:53:49 -0400 Received: from eggs.gnu.org ([2001:470:142:3::10]:44662) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1jYo2l-00066T-1x; Wed, 13 May 2020 05:51:15 -0400 Received: from relay.sw.ru ([185.231.240.75]:54006) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1jYo2f-0003ZC-7W; Wed, 13 May 2020 05:51:14 -0400 Received: from dhcp-172-16-25-136.sw.ru ([172.16.25.136] helo=localhost.sw.ru) by relay.sw.ru with esmtp (Exim 4.92.3) (envelope-from ) id 1jYo2V-0001e4-Ve; Wed, 13 May 2020 12:51:00 +0300 From: Andrey Shinkevich To: qemu-block@nongnu.org Subject: [PATCH v5 08/15] block: Use CAFs when working with backing chains Date: Wed, 13 May 2020 12:50:49 +0300 Message-Id: <1589363456-1035571-9-git-send-email-andrey.shinkevich@virtuozzo.com> X-Mailer: git-send-email 1.8.3.1 In-Reply-To: <1589363456-1035571-1-git-send-email-andrey.shinkevich@virtuozzo.com> References: <1589363456-1035571-1-git-send-email-andrey.shinkevich@virtuozzo.com> Received-SPF: pass client-ip=185.231.240.75; envelope-from=andrey.shinkevich@virtuozzo.com; helo=relay.sw.ru X-detected-operating-system: by eggs.gnu.org: First seen = 2020/05/13 05:51:06 X-ACL-Warn: Detected OS = Linux 3.1-3.10 X-Spam_score_int: -18 X-Spam_score: -1.9 X-Spam_bar: - X-Spam_report: (-1.9 / 5.0 requ) BAYES_00=-1.9, SPF_PASS=-0.001 autolearn=_AUTOLEARN 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: kwolf@redhat.com, fam@euphon.net, vsementsov@virtuozzo.com, armbru@redhat.com, qemu-devel@nongnu.org, stefanha@redhat.com, andrey.shinkevich@virtuozzo.com, den@openvz.org, mreitz@redhat.com, jsnow@redhat.com Errors-To: qemu-devel-bounces+incoming=patchwork.ozlabs.org@nongnu.org Sender: "Qemu-devel" From: Max Reitz Use child access functions when iterating through backing chains so filters do not break the chain. Signed-off-by: Max Reitz --- block.c | 40 ++++++++++++++++++++++++++++------------ 1 file changed, 28 insertions(+), 12 deletions(-) diff --git a/block.c b/block.c index 459412e..69e9152 100644 --- a/block.c +++ b/block.c @@ -4593,7 +4593,8 @@ int bdrv_change_backing_file(BlockDriverState *bs, } /* - * Finds the image layer in the chain that has 'bs' as its backing file. + * Finds the image layer in the chain that has 'bs' (or a filter on + * top of it) as its backing file. * * active is the current topmost image. * @@ -4605,11 +4606,18 @@ int bdrv_change_backing_file(BlockDriverState *bs, BlockDriverState *bdrv_find_overlay(BlockDriverState *active, BlockDriverState *bs) { - while (active && bs != backing_bs(active)) { - active = backing_bs(active); + bs = bdrv_skip_rw_filters(bs); + active = bdrv_skip_rw_filters(active); + + while (active) { + BlockDriverState *next = bdrv_backing_chain_next(active); + if (bs == next) { + return active; + } + active = next; } - return active; + return NULL; } /* Given a BDS, searches for the base layer. */ @@ -4761,9 +4769,7 @@ int bdrv_drop_intermediate(BlockDriverState *top, BlockDriverState *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 = backing_bs(explicit_top); - } + explicit_top = bdrv_skip_implicit_filters(explicit_top); update_inherits_from = bdrv_inherits_from_recursive(base, explicit_top); /* success - we can delete the intermediate states, and link top->base */ @@ -5205,7 +5211,7 @@ BlockDriverState *bdrv_lookup_bs(const char *device, bool bdrv_chain_contains(BlockDriverState *top, BlockDriverState *base) { while (top && top != base) { - top = backing_bs(top); + top = bdrv_filtered_bs(top); } return top != NULL; @@ -5466,7 +5472,17 @@ BlockDriverState *bdrv_find_backing_image(BlockDriverState *bs, is_protocol = path_has_protocol(backing_file); - for (curr_bs = bs; curr_bs->backing; curr_bs = curr_bs->backing->bs) { + /* + * 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 = bdrv_skip_rw_filters(bs); + bdrv_filtered_cow_child(curr_bs) != NULL; + curr_bs = bdrv_backing_chain_next(curr_bs)) + { + BlockDriverState *bs_below = bdrv_backing_chain_next(curr_bs); /* If either of the filename paths is actually a protocol, then * compare unmodified paths; otherwise make paths relative */ @@ -5474,7 +5490,7 @@ BlockDriverState *bdrv_find_backing_image(BlockDriverState *bs, char *backing_file_full_ret; if (strcmp(backing_file, curr_bs->backing_file) == 0) { - retval = curr_bs->backing->bs; + retval = bs_below; break; } /* Also check against the full backing filename for the image */ @@ -5484,7 +5500,7 @@ BlockDriverState *bdrv_find_backing_image(BlockDriverState *bs, bool equal = strcmp(backing_file, backing_file_full_ret) == 0; g_free(backing_file_full_ret); if (equal) { - retval = curr_bs->backing->bs; + retval = bs_below; break; } } @@ -5510,7 +5526,7 @@ BlockDriverState *bdrv_find_backing_image(BlockDriverState *bs, g_free(filename_tmp); if (strcmp(backing_file_full, filename_full) == 0) { - retval = curr_bs->backing->bs; + retval = bs_below; break; } }