From nobody Sun Nov 9 21:37:00 2025 Delivered-To: importer@patchew.org Received-SPF: pass (zoho.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; Authentication-Results: mx.zohomail.com; dkim=fail; spf=pass (zoho.com: domain of gnu.org designates 209.51.188.17 as permitted sender) smtp.mailfrom=qemu-devel-bounces+importer=patchew.org@nongnu.org Return-Path: Received: from lists.gnu.org (lists.gnu.org [209.51.188.17]) by mx.zohomail.com with SMTPS id 1551896252710649.7551816212837; Wed, 6 Mar 2019 10:17:32 -0800 (PST) Received: from localhost ([127.0.0.1]:37237 helo=lists.gnu.org) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1h1b6a-00085b-FS for importer@patchew.org; Wed, 06 Mar 2019 13:17:24 -0500 Received: from eggs.gnu.org ([209.51.188.92]:59617) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1h1b1t-0004Qp-E7 for qemu-devel@nongnu.org; Wed, 06 Mar 2019 13:12:34 -0500 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1h1b1m-00062c-5k for qemu-devel@nongnu.org; Wed, 06 Mar 2019 13:12:31 -0500 Received: from fanzine.igalia.com ([91.117.99.155]:59302) by eggs.gnu.org with esmtps (TLS1.0:RSA_AES_128_CBC_SHA1:16) (Exim 4.71) (envelope-from ) id 1h1b1e-0005g3-Mj; Wed, 06 Mar 2019 13:12:22 -0500 Received: from 87-92-21-153.bb.dnainternet.fi ([87.92.21.153] helo=perseus.local) by fanzine.igalia.com with esmtpsa (Cipher TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim) id 1h1b10-0004r1-LJ; Wed, 06 Mar 2019 19:11:38 +0100 Received: from berto by perseus.local with local (Exim 4.89) (envelope-from ) id 1h1b0m-0005Oc-Du; Wed, 06 Mar 2019 20:11:24 +0200 DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=igalia.com; s=20170329; h=References:In-Reply-To:References:In-Reply-To:Message-Id:Date:Subject:Cc:To:From; bh=0YhUuvFLmgoD37oa9jlpkUEEfg5ZKnhUSZdP0nnV22I=; b=KO5ecsCsIozhfy0WUNC9V3deR4Wv4+H68DNg0HekwV9zGwLi40C5o29L53lYbOAmbYinQ3zDLV2poC7lrag4Y4D7+zM8crnCEA7g182GO+2CaxiMh56ocSk34wKcYH85y9ZxICCbbC5XZHrUeFtbPDGrrH5aivXjGPXi3fIIycU0qlXMSOxSb70C1/1SvgJ9deodzmGgSD8AHHmzGaorcCHVTeBS1Pv/6gZGWIgODve/+9OTtavNNvkG3dF0saBr2DF55INUBUNCKUMRBtXDnNcFXY/mIoH8FvarpEdL9dkNyt/XJSLnyFE1Q8NDgbSnseikO3UOnqp3KIoQvW3XFA==; From: Alberto Garcia To: qemu-devel@nongnu.org Date: Wed, 6 Mar 2019 20:11:10 +0200 Message-Id: X-Mailer: git-send-email 2.11.0 In-Reply-To: References: In-Reply-To: References: X-detected-operating-system: by eggs.gnu.org: GNU/Linux 2.2.x-3.x (no timestamps) [generic] [fuzzy] X-Received-From: 91.117.99.155 Subject: [Qemu-devel] [PATCH v2 10/13] block: Add bdrv_reset_options_allowed() 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: Kevin Wolf , Alberto Garcia , qemu-block@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-Transfer-Encoding: quoted-printable MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" bdrv_reopen_prepare() receives a BDRVReopenState with (among other things) a new set of options to be applied to that BlockDriverState. If an option is missing then it means that we want to reset it to its default value rather than keep the previous one. This way the state of the block device after being reopened is comparable to that of a device added with "blockdev-add" using the same set of options. Not all options from all drivers can be changed this way, however. If the user attempts to reset an immutable option to its default value using this method then we must forbid it. This new function takes a BlockDriverState and a new set of options and checks if there's any option that was previously set but is missing from the new set of options. If the option is present in both sets we don't need to check that they have the same value. The loop at the end of bdrv_reopen_prepare() already takes care of that. Signed-off-by: Alberto Garcia --- block.c | 58 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 58 insertions(+) diff --git a/block.c b/block.c index 9c83adab7a..83788457e1 100644 --- a/block.c +++ b/block.c @@ -2984,6 +2984,53 @@ BlockDriverState *bdrv_open(const char *filename, co= nst char *reference, NULL, errp); } =20 +/* Return true if the NULL-terminated @list contains @str */ +static bool is_str_in_list(const char *str, const char *const *list) +{ + if (str && list) { + int i; + for (i =3D 0; list[i] !=3D NULL; i++) { + if (!strcmp(str, list[i])) { + return true; + } + } + } + return false; +} + +/* + * Check that every option set in @bs->options is also set in + * @new_opts. + * + * Options listed in the common_options list and in + * @bs->drv->mutable_opts are skipped. + * + * Return 0 on success, otherwise return -EINVAL and set @errp. + */ +static int bdrv_reset_options_allowed(BlockDriverState *bs, + const QDict *new_opts, Error **errp) +{ + const QDictEntry *e; + /* These options are common to all block drivers and are handled + * in bdrv_reopen_prepare() so they can be left out of @new_opts */ + const char *const common_options[] =3D { + "node-name", "discard", "cache.direct", "cache.no-flush", + "read-only", "auto-read-only", "detect-zeroes", NULL + }; + + for (e =3D qdict_first(bs->options); e; e =3D qdict_next(bs->options, = e)) { + if (!qdict_haskey(new_opts, e->key) && + !is_str_in_list(e->key, common_options) && + !is_str_in_list(e->key, bs->drv->mutable_opts)) { + error_setg(errp, "Option '%s' cannot be reset " + "to its default value", e->key); + return -EINVAL; + } + } + + return 0; +} + /* * Returns true if @child can be reached recursively from @bs */ @@ -3504,6 +3551,17 @@ int bdrv_reopen_prepare(BDRVReopenState *reopen_stat= e, BlockReopenQueue *queue, } =20 if (drv->bdrv_reopen_prepare) { + /* + * If a driver-specific option is missing, it means that we + * should reset it to its default value. + * But not all options allow that, so we need to check it first. + */ + ret =3D bdrv_reset_options_allowed(reopen_state->bs, + reopen_state->options, errp); + if (ret) { + goto error; + } + ret =3D drv->bdrv_reopen_prepare(reopen_state, queue, &local_err); if (ret) { if (local_err !=3D NULL) { --=20 2.11.0