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[82.57.51.214]) by smtp.gmail.com with ESMTPSA id o10-20020a056000010a00b00317b063590fsm1728460wrx.55.2023.08.01.09.03.43 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Tue, 01 Aug 2023 09:03:43 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1690905828; 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=e8287JZxFoKQYSGJDbSuajwiLjtWsxVc7SmfZQR3i98=; b=Fuf2xa2raLWESOZimGzmUvVEpchImDfwQfmhyDpUp6V9MNhXFQWSuMpoqQiRGRhgFIMPc7 iuKQVl2u+u+5Okm7oIEWxCvv2U+KeKftWlPuwYlfJ9QtxRh11bSE7RLPuFRScSBZVCVDpT IBIMJpBT5er+SJWr1ubIdeFFq3P/ym4= X-MC-Unique: SPBHbtrBPgKOhTiyNs0dTQ-1 X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20221208; t=1690905825; x=1691510625; h=content-transfer-encoding:mime-version:references:in-reply-to :message-id:date:subject:cc:to:from:x-gm-message-state:from:to:cc :subject:date:message-id:reply-to; bh=e8287JZxFoKQYSGJDbSuajwiLjtWsxVc7SmfZQR3i98=; b=SrEZjIbi+0uh3lGBGBbKouxOozIpDz9YTmU9M+8sN2Y4xTBHMzwutwePujajBPK8kZ aOOeYjGNF9G+wBg7aO/5GqPPQqeRgL5Yrqfdd/edhlV6jB4oXaYbrgNpes9NJma/Hodm 40FFEiQjzk84lwVfMSXvxnnQFZ5DeSZawvKUjffwQy8HT/vjYowaftIjXamRxtJhB9Dr YbJwM4JXpLyX/FiwF8JESsy825vPxqpyljRVen/eivIhHqelJ7BtKJprcYtQMdrZkFEl OT5HOr8dO8b/qo5VxK7T9WYRdAabMHTmtq2Kt3l+N8FYVpjlCTkf/65Jh0nlhKv5prti cFAg== X-Gm-Message-State: ABy/qLZbX0TNkycZGPXwoifZSmtu5h3YYRd3qCjnw/+YkJtUMj6YQy/Q zJvGUWrhgz6Btf6vclI7gHZipIfajGSr0vXFpnSECnA0695Rw0Jrpu4Hc/9f89gIBGiJPQWQCvt 9mJ4y1bzdfsi1RtqMOc1dqMp1rAYIXBkmHIEml+kJsWN0bWReMPD4LeTbq7MfmyqwmD+65MhgiT Y= X-Received: by 2002:adf:ecc8:0:b0:314:336e:d4d8 with SMTP id s8-20020adfecc8000000b00314336ed4d8mr2981954wro.8.1690905825350; Tue, 01 Aug 2023 09:03:45 -0700 (PDT) X-Google-Smtp-Source: APBJJlGR4eJpjWsyQgVBlBg3kNCqcMAnpXI5eMr020YCQd9JT1DlDHWmNGP+rSJJHWUiwO7+pTj+cg== X-Received: by 2002:adf:ecc8:0:b0:314:336e:d4d8 with SMTP id s8-20020adfecc8000000b00314336ed4d8mr2981916wro.8.1690905824600; Tue, 01 Aug 2023 09:03:44 -0700 (PDT) From: Stefano Garzarella To: qemu-devel@nongnu.org Cc: qemu-block@nongnu.org, Kevin Wolf , Stefan Hajnoczi , Hanna Reitz , Stefano Garzarella Subject: [PATCH 2/2] block/blkio: add more comments on the fd passing handling Date: Tue, 1 Aug 2023 18:03:32 +0200 Message-ID: <20230801160332.122564-3-sgarzare@redhat.com> X-Mailer: git-send-email 2.41.0 In-Reply-To: <20230801160332.122564-1-sgarzare@redhat.com> References: <20230801160332.122564-1-sgarzare@redhat.com> MIME-Version: 1.0 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=170.10.133.124; envelope-from=sgarzare@redhat.com; helo=us-smtp-delivery-124.mimecast.com 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_H4=0.001, RCVD_IN_MSPIKE_WL=0.001, SPF_HELO_NONE=0.001, SPF_PASS=-0.001, T_SCC_BODY_TEXT_LINE=-0.01 autolearn=ham autolearn_force=no X-Spam_action: no action X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: qemu-devel-bounces+importer=patchew.org@nongnu.org Sender: qemu-devel-bounces+importer=patchew.org@nongnu.org X-ZohoMail-DKIM: pass (identity @redhat.com) X-ZM-MESSAGEID: 1690905917058100003 Content-Type: text/plain; charset="utf-8" As Hanna pointed out, it is not clear in the code why qemu_open() can fail, and why blkio_set_int("fd") is not enough to discover the `fd` property support. Let's fix them by adding more details in the code comments. Suggested-by: Hanna Czenczek Signed-off-by: Stefano Garzarella Reviewed-by: Hanna Czenczek --- block/blkio.c | 15 ++++++++++++--- 1 file changed, 12 insertions(+), 3 deletions(-) diff --git a/block/blkio.c b/block/blkio.c index 2d53a865e7..848b8189d0 100644 --- a/block/blkio.c +++ b/block/blkio.c @@ -713,6 +713,12 @@ static int blkio_virtio_blk_connect(BlockDriverState *= bs, QDict *options, */ fd =3D qemu_open(path, O_RDWR, NULL); if (fd < 0) { + /* + * qemu_open() can fail if the user specifies a path that is n= ot + * a file or device, for example in the case of Unix Domain So= cket + * for the virtio-blk-vhost-user driver. In such cases let's h= ave + * libblkio open the path directly. + */ fd_supported =3D false; } else { ret =3D blkio_set_int(s->blkio, "fd", fd); @@ -734,9 +740,12 @@ static int blkio_virtio_blk_connect(BlockDriverState *= bs, QDict *options, =20 ret =3D blkio_connect(s->blkio); /* - * If the libblkio driver doesn't support the `fd` property, blkio_con= nect() - * will fail with -EINVAL. So let's try calling blkio_connect() again = by - * directly setting `path`. + * Before https://gitlab.com/libblkio/libblkio/-/merge_requests/208 + * (libblkio <=3D v1.3.0), setting the `fd` property is not enough to = check + * whether the driver supports the `fd` property or not. In that case, + * blkio_connect() will fail with -EINVAL. + * So let's try calling blkio_connect() again by directly setting `pat= h` + * to cover this scenario. */ if (fd_supported && ret =3D=3D -EINVAL) { fd_supported =3D false; --=20 2.41.0