From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id AC877C77B73 for ; Thu, 27 Apr 2023 13:06:04 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S243736AbjD0NGD (ORCPT ); Thu, 27 Apr 2023 09:06:03 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:34916 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S243664AbjD0NGC (ORCPT ); Thu, 27 Apr 2023 09:06:02 -0400 Received: from mail-wr1-x432.google.com (mail-wr1-x432.google.com [IPv6:2a00:1450:4864:20::432]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 368CE30F6 for ; Thu, 27 Apr 2023 06:06:01 -0700 (PDT) Received: by mail-wr1-x432.google.com with SMTP id ffacd0b85a97d-2f3fe12de15so5219993f8f.3 for ; Thu, 27 Apr 2023 06:06:01 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20221208; t=1682600759; x=1685192759; h=content-transfer-encoding:mime-version:references:in-reply-to :message-id:date:subject:cc:to:from:from:to:cc:subject:date :message-id:reply-to; bh=3g1OQGqGoXSb2dV4XTWgoIz+VvVcKQr9RVacWh/RneU=; b=luKy3C9R0PdDUl7i2D+lASwToDUbpHCuA0ALmqjVq31P5SnbjV2kBanD7muo/JpV5I ghyuVKKFrc95MtvBRhOKkDcfOf6NgbNDOGCXfvlpaoNf8xGoDYOZfCqp4t8zc0TVj0fn MwxnEkvpzOZh16e1If1ZgiXIxaFEKtkzCwJI/zeumbb8SvVoFizs+3nLWAl+x2v7wR5v yfyHe53dhz8lzVlVm7YQomXtMDIlel5f+XmaKgSteIAmF2SBzDRaY4Z8BmPV+Xz/hVR1 l/luIUF8PENBQCCmXrCMdWobp1tdyQj3iWn2DKtrmUfmbfrp52x+8wNLp+iGzSjrr+gF fMJA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20221208; t=1682600759; x=1685192759; 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=3g1OQGqGoXSb2dV4XTWgoIz+VvVcKQr9RVacWh/RneU=; b=LkFI/w5MMBQ+ERIF3JEqeSVpSt7P3bBbgSYB20krP4xToXTNpVo90ZLaM49NOMAXEH Y9DN4l2cYHW+h8zX8ZbN79OvH2tQqteDrqg7NHt/L8+VDKtqm1io49iSPr7v+0rvPnoD wEVnFrMTAMW/B2eSnFlpnAYaxNlWg3/WTIbx3ZuuUbuj91os9rzgL46wnBBAnwbDyGW5 yJuSeWU3pglImd4QKNVrGmRbVwEIO4lbKVxhR+m3Cko2Jql1RQPAygLrs1Vg2pcO1bEA 9gaLN/xIcANsVp3D8APDhxN/lWr0C+oebyECaynsIcr67cWOOh5DZ6JEm9ev5E5kNDjv MehQ== X-Gm-Message-State: AC+VfDxDlbGKpDEqTGEesnB3iLjCiuldw5XRmgksrwo3HbemovWDjQrh AwNjsVenL46fql5hZjolvuo= X-Google-Smtp-Source: ACHHUZ410P+6iNDBwFpM/cczm42QNd6Bsd+ipXsQMKrF2kKEga/aPcx1LdTmnRv80slxfQ3KmB7A7A== X-Received: by 2002:a5d:4acf:0:b0:2f5:ac53:c04f with SMTP id y15-20020a5d4acf000000b002f5ac53c04fmr1355568wrs.28.1682600759687; Thu, 27 Apr 2023 06:05:59 -0700 (PDT) Received: from amir-ThinkPad-T480.lan ([5.29.249.86]) by smtp.gmail.com with ESMTPSA id k17-20020a5d6291000000b002c561805a4csm18533426wru.45.2023.04.27.06.05.58 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Thu, 27 Apr 2023 06:05:59 -0700 (PDT) From: Amir Goldstein To: Miklos Szeredi Cc: Alexander Larsson , linux-unionfs@vger.kernel.org Subject: [PATCH v2 12/13] ovl: prepare for lazy lookup of lowerdata inode Date: Thu, 27 Apr 2023 16:05:38 +0300 Message-Id: <20230427130539.2798797-13-amir73il@gmail.com> X-Mailer: git-send-email 2.34.1 In-Reply-To: <20230427130539.2798797-1-amir73il@gmail.com> References: <20230427130539.2798797-1-amir73il@gmail.com> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-unionfs@vger.kernel.org Make the code handle the case of numlower > 1 and missing lowerdata dentry gracefully. Missing lowerdata dentry is an indication for lazy lookup of lowerdata and in that case the lowerdata_redirect path is stored in ovl_inode. Following commits will defer lookup and perform the lazy lookup on access. Reviewed-by: Alexander Larsson Signed-off-by: Amir Goldstein --- fs/overlayfs/file.c | 7 +++++++ fs/overlayfs/inode.c | 18 ++++++++++++++---- fs/overlayfs/super.c | 11 +++++++++++ fs/overlayfs/util.c | 2 +- 4 files changed, 33 insertions(+), 5 deletions(-) diff --git a/fs/overlayfs/file.c b/fs/overlayfs/file.c index 7c04f033aadd..951683a66ff6 100644 --- a/fs/overlayfs/file.c +++ b/fs/overlayfs/file.c @@ -115,6 +115,9 @@ static int ovl_real_fdget_meta(const struct file *file, struct fd *real, ovl_path_real(dentry, &realpath); else ovl_path_realdata(dentry, &realpath); + /* TODO: lazy lookup of lowerdata */ + if (!realpath.dentry) + return -EIO; /* Has it been copied up since we'd opened it? */ if (unlikely(file_inode(real->file) != d_inode(realpath.dentry))) { @@ -158,6 +161,10 @@ static int ovl_open(struct inode *inode, struct file *file) file->f_flags &= ~(O_CREAT | O_EXCL | O_NOCTTY | O_TRUNC); ovl_path_realdata(dentry, &realpath); + /* TODO: lazy lookup of lowerdata */ + if (!realpath.dentry) + return -EIO; + realfile = ovl_open_realfile(file, &realpath); if (IS_ERR(realfile)) return PTR_ERR(realfile); diff --git a/fs/overlayfs/inode.c b/fs/overlayfs/inode.c index a7529b6a86e6..ebbe13bccc97 100644 --- a/fs/overlayfs/inode.c +++ b/fs/overlayfs/inode.c @@ -240,15 +240,22 @@ int ovl_getattr(struct mnt_idmap *idmap, const struct path *path, /* * If lower is not same as lowerdata or if there was * no origin on upper, we can end up here. + * With lazy lowerdata lookup, guess lowerdata blocks + * from size to avoid lowerdata lookup on stat(2). */ struct kstat lowerdatastat; u32 lowermask = STATX_BLOCKS; ovl_path_lowerdata(dentry, &realpath); - err = vfs_getattr(&realpath, &lowerdatastat, - lowermask, flags); - if (err) - goto out; + if (realpath.dentry) { + err = vfs_getattr(&realpath, &lowerdatastat, + lowermask, flags); + if (err) + goto out; + } else { + lowerdatastat.blocks = + round_up(stat->size, stat->blksize) >> 9; + } stat->blocks = lowerdatastat.blocks; } } @@ -710,6 +717,9 @@ static int ovl_fiemap(struct inode *inode, struct fiemap_extent_info *fieinfo, struct inode *realinode = ovl_inode_realdata(inode); const struct cred *old_cred; + if (!realinode) + return -EIO; + if (!realinode->i_op->fiemap) return -EOPNOTSUPP; diff --git a/fs/overlayfs/super.c b/fs/overlayfs/super.c index b960b9d84b66..ad9a68bec565 100644 --- a/fs/overlayfs/super.c +++ b/fs/overlayfs/super.c @@ -81,6 +81,14 @@ static struct dentry *ovl_d_real(struct dentry *dentry, if (real && !inode && ovl_has_upperdata(d_inode(dentry))) return real; + /* + * XXX: We may need lazy lookup of lowerdata for !inode case to return + * the real lowerdata dentry. The only current caller of d_real() with + * NULL inode is d_real_inode() from trace_uprobe and this caller is + * likely going to be followed reading from the file, before placing + * uprobes on offset within the file, so lowerdata should be available + * when setting the uprobe. + */ lower = ovl_dentry_lowerdata(dentry); if (!lower) goto bug; @@ -103,6 +111,9 @@ static int ovl_revalidate_real(struct dentry *d, unsigned int flags, bool weak) { int ret = 1; + if (!d) + return 1; + if (weak) { if (d->d_flags & DCACHE_OP_WEAK_REVALIDATE) ret = d->d_op->d_weak_revalidate(d, flags); diff --git a/fs/overlayfs/util.c b/fs/overlayfs/util.c index ad93a3132495..9b7c0163734a 100644 --- a/fs/overlayfs/util.c +++ b/fs/overlayfs/util.c @@ -159,7 +159,7 @@ void ovl_dentry_init_flags(struct dentry *dentry, struct dentry *upperdentry, if (upperdentry) flags |= upperdentry->d_flags; - for (i = 0; i < ovl_numlower(oe); i++) + for (i = 0; i < ovl_numlower(oe) && lowerstack[i].dentry; i++) flags |= lowerstack[i].dentry->d_flags; spin_lock(&dentry->d_lock); -- 2.34.1