From patchwork Sat Apr 11 12:09:03 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Greg KH X-Patchwork-Id: 227987 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=-6.8 required=3.0 tests=DKIMWL_WL_HIGH, DKIM_SIGNED, DKIM_VALID, HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI, SIGNED_OFF_BY, 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 3BADEC2BBC7 for ; Sat, 11 Apr 2020 12:28:37 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 0CE94214D8 for ; Sat, 11 Apr 2020 12:28:37 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1586608117; bh=FcdJVVEq8CmZcnqI0D3HsC3RfT7erIPVkgkxj+RYtp4=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=0ugtmfI4wqZwX4ZrlfIafexrAkIFppviR21JpqaxyhvaY9NTNWhN/lxwQaXnCCJpv pjLX7lgU85odYxOw3NzfRvclBGHxZanBZTxL/wYx4yb5h2JLpssj81IESp8mFGbZ20 rcFtF5shlk/J+gJ7l9yU6IjHCx4pR+C+/vPvyOxI= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726879AbgDKM2c (ORCPT ); Sat, 11 Apr 2020 08:28:32 -0400 Received: from mail.kernel.org ([198.145.29.99]:44980 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727233AbgDKMMY (ORCPT ); Sat, 11 Apr 2020 08:12:24 -0400 Received: from localhost (83-86-89-107.cable.dynamic.v4.ziggo.nl [83.86.89.107]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id 24D9C215A4; Sat, 11 Apr 2020 12:12:23 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1586607143; bh=FcdJVVEq8CmZcnqI0D3HsC3RfT7erIPVkgkxj+RYtp4=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=CoCNRBUC2a/c71N7dFxc/ui/X4n04CZ3T9K8we0y5GODo+YY2up0PiMUyk7zZBp8f U/KN1urDYRHNsOAkRexcnUV/TEHKklGNvHd0WMtkCGl9Qc1TLoRUT3FJNxx4utlHUa 14DbPyg6sRuIP8xoEnbD5sUUISlVwCpWQF+i982k= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Xiubo Li , Jeff Layton , Ilya Dryomov , Luis Henriques Subject: [PATCH 4.9 24/32] ceph: remove the extra slashes in the server path Date: Sat, 11 Apr 2020 14:09:03 +0200 Message-Id: <20200411115422.001067703@linuxfoundation.org> X-Mailer: git-send-email 2.26.0 In-Reply-To: <20200411115418.455500023@linuxfoundation.org> References: <20200411115418.455500023@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Sender: stable-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: stable@vger.kernel.org From: Xiubo Li commit 4fbc0c711b2464ee1551850b85002faae0b775d5 upstream. It's possible to pass the mount helper a server path that has more than one contiguous slash character. For example: $ mount -t ceph 192.168.195.165:40176:/// /mnt/cephfs/ In the MDS server side the extra slashes of the server path will be treated as snap dir, and then we can get the following debug logs: ceph: mount opening path // ceph: open_root_inode opening '//' ceph: fill_trace 0000000059b8a3bc is_dentry 0 is_target 1 ceph: alloc_inode 00000000dc4ca00b ceph: get_inode created new inode 00000000dc4ca00b 1.ffffffffffffffff ino 1 ceph: get_inode on 1=1.ffffffffffffffff got 00000000dc4ca00b And then when creating any new file or directory under the mount point, we can hit the following BUG_ON in ceph_fill_trace(): BUG_ON(ceph_snap(dir) != dvino.snap); Have the client ignore the extra slashes in the server path when mounting. This will also canonicalize the path, so that identical mounts can be consilidated. 1) "//mydir1///mydir//" 2) "/mydir1/mydir" 3) "/mydir1/mydir/" Regardless of the internal treatment of these paths, the kernel still stores the original string including the leading '/' for presentation to userland. URL: https://tracker.ceph.com/issues/42771 Signed-off-by: Xiubo Li Reviewed-by: Jeff Layton Signed-off-by: Ilya Dryomov Signed-off-by: Luis Henriques Signed-off-by: Greg Kroah-Hartman --- fs/ceph/super.c | 118 ++++++++++++++++++++++++++++++++++++++++++++++---------- 1 file changed, 99 insertions(+), 19 deletions(-) --- a/fs/ceph/super.c +++ b/fs/ceph/super.c @@ -85,7 +85,6 @@ static int ceph_statfs(struct dentry *de return 0; } - static int ceph_sync_fs(struct super_block *sb, int wait) { struct ceph_fs_client *fsc = ceph_sb_to_client(sb); @@ -321,6 +320,73 @@ static int strcmp_null(const char *s1, c return strcmp(s1, s2); } +/** + * path_remove_extra_slash - Remove the extra slashes in the server path + * @server_path: the server path and could be NULL + * + * Return NULL if the path is NULL or only consists of "/", or a string + * without any extra slashes including the leading slash(es) and the + * slash(es) at the end of the server path, such as: + * "//dir1////dir2///" --> "dir1/dir2" + */ +static char *path_remove_extra_slash(const char *server_path) +{ + const char *path = server_path; + const char *cur, *end; + char *buf, *p; + int len; + + /* if the server path is omitted */ + if (!path) + return NULL; + + /* remove all the leading slashes */ + while (*path == '/') + path++; + + /* if the server path only consists of slashes */ + if (*path == '\0') + return NULL; + + len = strlen(path); + + buf = kmalloc(len + 1, GFP_KERNEL); + if (!buf) + return ERR_PTR(-ENOMEM); + + end = path + len; + p = buf; + do { + cur = strchr(path, '/'); + if (!cur) + cur = end; + + len = cur - path; + + /* including one '/' */ + if (cur != end) + len += 1; + + memcpy(p, path, len); + p += len; + + while (cur <= end && *cur == '/') + cur++; + path = cur; + } while (path < end); + + *p = '\0'; + + /* + * remove the last slash if there has and just to make sure that + * we will get something like "dir1/dir2" + */ + if (*(--p) == '/') + *p = '\0'; + + return buf; +} + static int compare_mount_options(struct ceph_mount_options *new_fsopt, struct ceph_options *new_opt, struct ceph_fs_client *fsc) @@ -328,6 +394,7 @@ static int compare_mount_options(struct struct ceph_mount_options *fsopt1 = new_fsopt; struct ceph_mount_options *fsopt2 = fsc->mount_options; int ofs = offsetof(struct ceph_mount_options, snapdir_name); + char *p1, *p2; int ret; ret = memcmp(fsopt1, fsopt2, ofs); @@ -341,7 +408,17 @@ static int compare_mount_options(struct if (ret) return ret; - ret = strcmp_null(fsopt1->server_path, fsopt2->server_path); + p1 = path_remove_extra_slash(fsopt1->server_path); + if (IS_ERR(p1)) + return PTR_ERR(p1); + p2 = path_remove_extra_slash(fsopt2->server_path); + if (IS_ERR(p2)) { + kfree(p1); + return PTR_ERR(p2); + } + ret = strcmp_null(p1, p2); + kfree(p1); + kfree(p2); if (ret) return ret; @@ -396,12 +473,14 @@ static int parse_mount_options(struct ce */ dev_name_end = strchr(dev_name, '/'); if (dev_name_end) { - if (strlen(dev_name_end) > 1) { - fsopt->server_path = kstrdup(dev_name_end, GFP_KERNEL); - if (!fsopt->server_path) { - err = -ENOMEM; - goto out; - } + /* + * The server_path will include the whole chars from userland + * including the leading '/'. + */ + fsopt->server_path = kstrdup(dev_name_end, GFP_KERNEL); + if (!fsopt->server_path) { + err = -ENOMEM; + goto out; } } else { dev_name_end = dev_name + strlen(dev_name); @@ -725,7 +804,6 @@ static void destroy_caches(void) ceph_fscache_unregister(); } - /* * ceph_umount_begin - initiate forced umount. Tear down down the * mount, skipping steps that may hang while waiting for server(s). @@ -812,9 +890,6 @@ out: return root; } - - - /* * mount: join the ceph cluster, and open root directory. */ @@ -828,24 +903,29 @@ static struct dentry *ceph_real_mount(st mutex_lock(&fsc->client->mount_mutex); if (!fsc->sb->s_root) { - const char *path; + const char *path, *p; err = __ceph_open_session(fsc->client, started); if (err < 0) goto out; - if (!fsc->mount_options->server_path) { - path = ""; - dout("mount opening path \\t\n"); - } else { - path = fsc->mount_options->server_path + 1; - dout("mount opening path %s\n", path); + p = path_remove_extra_slash(fsc->mount_options->server_path); + if (IS_ERR(p)) { + err = PTR_ERR(p); + goto out; } + /* if the server path is omitted or just consists of '/' */ + if (!p) + path = ""; + else + path = p; + dout("mount opening path '%s'\n", path); err = ceph_fs_debugfs_init(fsc); if (err < 0) goto out; root = open_root_dentry(fsc, path, started); + kfree(p); if (IS_ERR(root)) { err = PTR_ERR(root); goto out;