From mboxrd@z Thu Jan 1 00:00:00 1970 Delivery-date: Wed, 03 Jan 2024 19:35:17 +0100 Received: from metis.whiteo.stw.pengutronix.de ([2a0a:edc0:2:b01:1d::104]) by lore.white.stw.pengutronix.de with esmtps (TLS1.3) tls TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384 (Exim 4.96) (envelope-from ) id 1rL65F-002NzZ-2C for lore@lore.pengutronix.de; Wed, 03 Jan 2024 19:35:17 +0100 Received: from bombadil.infradead.org ([2607:7c80:54:3::133]) by metis.whiteo.stw.pengutronix.de with esmtps (TLS1.3:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.92) (envelope-from ) id 1rL659-0006NJ-GR for lore@pengutronix.de; Wed, 03 Jan 2024 19:35:17 +0100 DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20210309; h=Sender:List-Subscribe:List-Help :List-Post:List-Archive:List-Unsubscribe:List-Id:Content-Transfer-Encoding: MIME-Version:References:In-Reply-To:Message-Id:Date:Subject:Cc:To:From: Reply-To:Content-Type:Content-ID:Content-Description:Resent-Date:Resent-From: Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Owner; bh=T5quzTbDz1MLgNy1Ft6KnSnCY0zYCzl+fSEOO/+k6Yc=; b=N5M1XHpCVhq3S7K05GEfcNcsab D5/bw8w3VpFKfCuudP7Sza0LcBgPFBJaUPvqIStW3hLe2HaHh1bG9Z6drU2XrQZaqX5tTdnlcjmmE 1KUNX5i1E7RdObFAH5JuowEW/Hj6lAqeYy7g819eKHT5C1/HLunkg7a2Y+mFVl1G5OcwftISqVHVr 5PZgEclfzf4Yr9jeFC7v3z3Vr/XIfPGCm+mLDi7jGIoNMSHcQtoI+HyMJFUXd3fUQoBxvWDGvuETJ BkS+fOlg1ffahDwhPMlt1Xjj+SwP1UrbgBRaKujv+zae9O2c/cGSqqU+S/w650kW3LFfiZmgCgTNh Fomk4srw==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.96 #2 (Red Hat Linux)) id 1rL63V-00Bk06-2q; Wed, 03 Jan 2024 18:33:29 +0000 Received: from desiato.infradead.org ([2001:8b0:10b:1:d65d:64ff:fe57:4e05]) by bombadil.infradead.org with esmtps (Exim 4.96 #2 (Red Hat Linux)) id 1rL61H-00BhL9-1M for barebox@bombadil.infradead.org; Wed, 03 Jan 2024 18:31:11 +0000 DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=infradead.org; s=desiato.20200630; h=Content-Transfer-Encoding:MIME-Version :References:In-Reply-To:Message-Id:Date:Subject:Cc:To:From:Sender:Reply-To: Content-Type:Content-ID:Content-Description; bh=T5quzTbDz1MLgNy1Ft6KnSnCY0zYCzl+fSEOO/+k6Yc=; b=YFL4os/br34mJ7pXHcDGz3kxDl qcEZtb6AmV2pTJ7rZzVBQAhbCIdHz5Xj2bsmgx1uz1CrxE95QibQ6i+QSXK8EWR4XBC2apQQQmfdb xT8aC5PQTIVEAhX7rAHBVnktv6xy6e/6lyiXM7EK8WLQQeV2KD4nZ9qz8xkLeFmEcmj4vuFmZ+Oa8 cJ4P0BchOCb3EjUNTL328+/PBZmWfVw18ak91RGhXAK8Xfl1lgAvlLVXY/LWBVC0wSQoH5UcXmnLA It8va6TKy8VNsaojODli1YVzZsxCxo/xG0L2Vrw+/WCXH7ncbPsWOmVmiREWknWCPVmc+bGyB7E+C yFUYK+nQ==; Received: from metis.whiteo.stw.pengutronix.de ([2a0a:edc0:2:b01:1d::104]) by desiato.infradead.org with esmtps (Exim 4.96 #2 (Red Hat Linux)) id 1rL618-005eC2-2w for barebox@lists.infradead.org; Wed, 03 Jan 2024 18:31:10 +0000 Received: from drehscheibe.grey.stw.pengutronix.de ([2a0a:edc0:0:c01:1d::a2]) by metis.whiteo.stw.pengutronix.de with esmtps (TLS1.3:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.92) (envelope-from ) id 1rL613-0001fN-Jl; Wed, 03 Jan 2024 19:30:57 +0100 Received: from [2a0a:edc0:0:1101:1d::54] (helo=dude05.red.stw.pengutronix.de) by drehscheibe.grey.stw.pengutronix.de with esmtps (TLS1.3) tls TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384 (Exim 4.94.2) (envelope-from ) id 1rL613-000AxU-5w; Wed, 03 Jan 2024 19:30:57 +0100 Received: from localhost ([::1] helo=dude05.red.stw.pengutronix.de) by dude05.red.stw.pengutronix.de with esmtp (Exim 4.96) (envelope-from ) id 1rL5k2-001j4X-21; Wed, 03 Jan 2024 19:13:22 +0100 From: Ahmad Fatoum To: barebox@lists.infradead.org Cc: Ahmad Fatoum Date: Wed, 3 Jan 2024 19:11:57 +0100 Message-Id: <20240103181312.409668-38-a.fatoum@pengutronix.de> X-Mailer: git-send-email 2.39.2 In-Reply-To: <20240103181312.409668-1-a.fatoum@pengutronix.de> References: <20240103181312.409668-1-a.fatoum@pengutronix.de> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20240103_183103_046979_2ECF9366 X-CRM114-Status: GOOD ( 15.99 ) X-BeenThere: barebox@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: "barebox" X-SA-Exim-Connect-IP: 2607:7c80:54:3::133 X-SA-Exim-Mail-From: barebox-bounces+lore=pengutronix.de@lists.infradead.org X-Spam-Checker-Version: SpamAssassin 3.4.2 (2018-09-13) on metis.whiteo.stw.pengutronix.de X-Spam-Level: X-Spam-Status: No, score=-6.3 required=4.0 tests=AWL,BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,RCVD_IN_DNSWL_MED,SPF_HELO_NONE,SPF_NONE, T_SCC_BODY_TEXT_LINE autolearn=unavailable autolearn_force=no version=3.4.2 Subject: [PATCH 037/112] fs: support different root directories X-SA-Exim-Version: 4.2.1 (built Wed, 08 May 2019 21:11:16 +0000) X-SA-Exim-Scanned: Yes (on metis.whiteo.stw.pengutronix.de) A root directory is a directory that has itself as the parent. There is only one such directory, but for chroot support we will want to stop path resolution at a non-root directory as well. We do this by giving struct nameidata a d_root field, which serves as a root directory for the lookup. As we initialize it to the global root directory, this introduces no functional change. Signed-off-by: Ahmad Fatoum --- fs/fs.c | 14 ++++++++------ 1 file changed, 8 insertions(+), 6 deletions(-) diff --git a/fs/fs.c b/fs/fs.c index 54f38aa2e63b..7fc638451f13 100644 --- a/fs/fs.c +++ b/fs/fs.c @@ -1623,6 +1623,7 @@ struct nameidata { } *stack, internal[EMBEDDED_LEVELS]; struct filename *name; struct inode *link_inode; + struct dentry *d_root; }; struct filename { @@ -1635,6 +1636,7 @@ static void set_nameidata(struct nameidata *p, struct filename *name) p->stack = p->internal; p->name = name; p->total_link_count = 0; + p->d_root = d_root; } static void path_get(const struct path *path) @@ -1820,16 +1822,16 @@ static int lookup_fast(struct nameidata *nd, struct path *path) * Return 1 if we went up a level and 0 if we were already at the * root. */ -static int follow_up(struct path *path) +static int follow_up(struct nameidata *nd) { - struct vfsmount *parent, *mnt = path->mnt; + struct path *path = &nd->path; + struct vfsmount *mnt = path->mnt; struct dentry *mountpoint; - parent = mnt->parent; - if (parent == mnt) + if (nd->d_root == path->dentry) return 0; - mntget(parent); + mntget(mnt->parent); mountpoint = dget(mnt->mountpoint); dput(path->dentry); path->dentry = mountpoint; @@ -1871,7 +1873,7 @@ static int follow_dotdot(struct nameidata *nd) break; } - if (!follow_up(&nd->path)) + if (!follow_up(nd)) break; } -- 2.39.2