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 X-Spam-Level: X-Spam-Status: No, score=-19.2 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,USER_AGENT_GIT autolearn=unavailable autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 19EBEC433E6 for ; Mon, 15 Mar 2021 18:08:20 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id E2E5A64F40 for ; Mon, 15 Mar 2021 18:08:19 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S232280AbhCOSHr (ORCPT ); Mon, 15 Mar 2021 14:07:47 -0400 Received: from mail.kernel.org ([198.145.29.99]:48694 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S231444AbhCOSHV (ORCPT ); Mon, 15 Mar 2021 14:07:21 -0400 Received: by mail.kernel.org (Postfix) with ESMTPSA id 484BA64F2B; Mon, 15 Mar 2021 18:07:20 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1615831640; bh=ExJkSDJZzOihB9xhPHG0ijWVccQ2cA9//wNyKOoa05w=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=jivERlwLriflGwUsD07KAhUqmc2S0A94JzIQ2zgpDff921o4h9SesZiyJpUVi5SIS 5iKlLw5PvTkTHlvgxB3glc15m3PH5EXGCOxNXX8HaA2Z4eXtJro6xmkKUL2T+cEZah WGzVJMcs1CFXBiD6AuBmrehopRqPc0YIubWjZawS8nkuhC4d+C9+vbtUib9Wtd0CGl y/kCDYtLnA9HHj683DMDBVrhayLiw6vLsydgcXFBPv5Aiz4ubaCpOO6NN/Mdh4C47u K6meKM9+2EVJAruPWeXeX8dM0/kj90McvB0f/L9aIBAXaK5iFjwSTQNVPE/6goD757 WjaF1zuk8WJRA== From: Jeff Layton To: ceph-devel@vger.kernel.org, idryomov@gmail.com Cc: linux-fsdevel@vger.kernel.org, viro@zeniv.linux.org.uk Subject: [PATCH 2/2] ceph: don't use d_add in ceph_handle_snapdir Date: Mon, 15 Mar 2021 14:07:17 -0400 Message-Id: <20210315180717.266155-3-jlayton@kernel.org> X-Mailer: git-send-email 2.30.2 In-Reply-To: <20210315180717.266155-1-jlayton@kernel.org> References: <20210315180717.266155-1-jlayton@kernel.org> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: ceph-devel@vger.kernel.org It's possible ceph_get_snapdir could end up finding a (disconnected) inode that already exists in the cache. Change the prototype for ceph_handle_snapdir to return a dentry pointer and have it use d_splice_alias so we don't end up with an aliased dentry in the cache. Reported-by: Al Viro Signed-off-by: Jeff Layton --- fs/ceph/dir.c | 30 ++++++++++++++++++------------ fs/ceph/file.c | 6 ++++-- fs/ceph/super.h | 2 +- 3 files changed, 23 insertions(+), 15 deletions(-) diff --git a/fs/ceph/dir.c b/fs/ceph/dir.c index 113f669d71dd..4b871b7017a0 100644 --- a/fs/ceph/dir.c +++ b/fs/ceph/dir.c @@ -667,8 +667,8 @@ static loff_t ceph_dir_llseek(struct file *file, loff_t offset, int whence) /* * Handle lookups for the hidden .snap directory. */ -int ceph_handle_snapdir(struct ceph_mds_request *req, - struct dentry *dentry, int err) +struct dentry *ceph_handle_snapdir(struct ceph_mds_request *req, + struct dentry *dentry, int err) { struct ceph_fs_client *fsc = ceph_sb_to_client(dentry->d_sb); struct inode *parent = d_inode(dentry->d_parent); /* we hold i_mutex */ @@ -676,18 +676,19 @@ int ceph_handle_snapdir(struct ceph_mds_request *req, /* .snap dir? */ if (err == -ENOENT && ceph_snap(parent) == CEPH_NOSNAP && - strcmp(dentry->d_name.name, - fsc->mount_options->snapdir_name) == 0) { + strcmp(dentry->d_name.name, fsc->mount_options->snapdir_name) == 0) { + struct dentry *res; struct inode *inode = ceph_get_snapdir(parent); + if (IS_ERR(inode)) - return PTR_ERR(inode); - dout("ENOENT on snapdir %p '%pd', linking to snapdir %p\n", - dentry, dentry, inode); - BUG_ON(!d_unhashed(dentry)); - d_add(dentry, inode); - err = 0; + return ERR_CAST(inode); + res = d_splice_alias(inode, dentry); + dout("ENOENT on snapdir %p '%pd', linking to snapdir %p. Spliced dentry %p\n", + dentry, dentry, inode, res); + if (res) + dentry = res; } - return err; + return dentry; } /* @@ -743,6 +744,7 @@ static struct dentry *ceph_lookup(struct inode *dir, struct dentry *dentry, struct ceph_fs_client *fsc = ceph_sb_to_client(dir->i_sb); struct ceph_mds_client *mdsc = ceph_sb_to_mdsc(dir->i_sb); struct ceph_mds_request *req; + struct dentry *res; int op; int mask; int err; @@ -793,7 +795,11 @@ static struct dentry *ceph_lookup(struct inode *dir, struct dentry *dentry, req->r_parent = dir; set_bit(CEPH_MDS_R_PARENT_LOCKED, &req->r_req_flags); err = ceph_mdsc_do_request(mdsc, NULL, req); - err = ceph_handle_snapdir(req, dentry, err); + res = ceph_handle_snapdir(req, dentry, err); + if (IS_ERR(res)) + err = PTR_ERR(res); + else + dentry = res; dentry = ceph_finish_lookup(req, dentry, err); ceph_mdsc_put_request(req); /* will dput(dentry) */ dout("lookup result=%p\n", dentry); diff --git a/fs/ceph/file.c b/fs/ceph/file.c index 209535d5b8d3..847beb9f43dd 100644 --- a/fs/ceph/file.c +++ b/fs/ceph/file.c @@ -739,9 +739,11 @@ int ceph_atomic_open(struct inode *dir, struct dentry *dentry, err = ceph_mdsc_do_request(mdsc, (flags & (O_CREAT|O_TRUNC)) ? dir : NULL, req); - err = ceph_handle_snapdir(req, dentry, err); - if (err) + dentry = ceph_handle_snapdir(req, dentry, err); + if (IS_ERR(dentry)) { + err = PTR_ERR(dentry); goto out_req; + } if ((flags & O_CREAT) && !req->r_reply_info.head->is_dentry) err = ceph_handle_notrace_create(dir, dentry); diff --git a/fs/ceph/super.h b/fs/ceph/super.h index 188565d806b2..07a3fb52ae30 100644 --- a/fs/ceph/super.h +++ b/fs/ceph/super.h @@ -1193,7 +1193,7 @@ extern const struct dentry_operations ceph_dentry_ops; extern loff_t ceph_make_fpos(unsigned high, unsigned off, bool hash_order); extern int ceph_handle_notrace_create(struct inode *dir, struct dentry *dentry); -extern int ceph_handle_snapdir(struct ceph_mds_request *req, +extern struct dentry *ceph_handle_snapdir(struct ceph_mds_request *req, struct dentry *dentry, int err); extern struct dentry *ceph_finish_lookup(struct ceph_mds_request *req, struct dentry *dentry, int err); -- 2.30.2