From patchwork Tue Jul 1 08:00:07 2014 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Satoru Takeuchi X-Patchwork-Id: 4457031 Return-Path: X-Original-To: patchwork-linux-btrfs@patchwork.kernel.org Delivered-To: patchwork-parsemail@patchwork2.web.kernel.org Received: from mail.kernel.org (mail.kernel.org [198.145.19.201]) by patchwork2.web.kernel.org (Postfix) with ESMTP id C11D9BEEAA for ; Tue, 1 Jul 2014 08:00:32 +0000 (UTC) Received: from mail.kernel.org (localhost [127.0.0.1]) by mail.kernel.org (Postfix) with ESMTP id 24E7E20220 for ; Tue, 1 Jul 2014 08:00:29 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 8ABD820221 for ; Tue, 1 Jul 2014 08:00:27 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1757535AbaGAIAY (ORCPT ); Tue, 1 Jul 2014 04:00:24 -0400 Received: from fgwmail.fujitsu.co.jp ([164.71.1.133]:54832 "EHLO fgwmail.fujitsu.co.jp" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754949AbaGAIAX (ORCPT ); Tue, 1 Jul 2014 04:00:23 -0400 Received: from kw-mxq.gw.nic.fujitsu.com (unknown [10.0.237.131]) by fgwmail.fujitsu.co.jp (Postfix) with ESMTP id CDE563EE0C5 for ; Tue, 1 Jul 2014 17:00:21 +0900 (JST) Received: from s2.gw.fujitsu.co.jp (s2.gw.nic.fujitsu.com [10.0.50.92]) by kw-mxq.gw.nic.fujitsu.com (Postfix) with ESMTP id 76325AC078F for ; Tue, 1 Jul 2014 17:00:20 +0900 (JST) Received: from g01jpfmpwkw01.exch.g01.fujitsu.local (g01jpfmpwkw01.exch.g01.fujitsu.local [10.0.193.38]) by s2.gw.fujitsu.co.jp (Postfix) with ESMTP id 11162E08014 for ; Tue, 1 Jul 2014 17:00:20 +0900 (JST) Received: from g01jpexchkw37.g01.fujitsu.local (unknown [10.0.193.4]) by g01jpfmpwkw01.exch.g01.fujitsu.local (Postfix) with ESMTP id 5D0B0692614; Tue, 1 Jul 2014 17:00:18 +0900 (JST) X-SecurityPolicyCheck: OK by SHieldMailChecker v2.0.1 X-SHieldMailCheckerPolicyVersion: FJ-ISEC-20120718-4 Message-ID: <53B26A87.4080800@jp.fujitsu.com> Date: Tue, 1 Jul 2014 17:00:07 +0900 From: Satoru Takeuchi User-Agent: Mozilla/5.0 (Windows NT 6.1; rv:24.0) Gecko/20100101 Thunderbird/24.3.0 MIME-Version: 1.0 To: Wang Shilong , Anand Jain , CC: , , , Subject: [PATCH v6] btrfs: label should not contain return char References: <1400519071-5580-1-git-send-email-anand.jain@oracle.com> <1400813402-27474-1-git-send-email-anand.jain@oracle.com> <53B245AA.6060209@jp.fujitsu.com> <53B25931.2030200@cn.fujitsu.com> In-Reply-To: <53B25931.2030200@cn.fujitsu.com> X-SecurityPolicyCheck-GC: OK by FENCE-Mail Sender: linux-btrfs-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-btrfs@vger.kernel.org X-Spam-Status: No, score=-6.9 required=5.0 tests=BAYES_00, RCVD_IN_DNSWL_HI, T_RP_MATCHES_RCVD, UNPARSEABLE_RELAY autolearn=ham version=3.3.1 X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on mail.kernel.org X-Virus-Scanned: ClamAV using ClamSMTP Hi Wang, (2014/07/01 15:46), Wang Shilong wrote: > Hi Satoru and all, > > I think there maybe a leftover issue. > That is if we don't set label, in default it will output a blank line. > > Steps to reproduce: > > # mkfs.btrfs -f /dev/sdb > # mount /dev/sdb > # cat /sys/fs/btrfs//label -->an extra line will be outputed. > > This is because in btrfs_label_show(), we did something like this directly: > > return snprintf(buf, PAGE_SIZE, "%s\n", fs_info->super_copy->label); > > Maybe we can have a check whether label is NULL before we output? > otherwise,the > extra blank line is outputed, IMO this is not so nice thing! OK, how about it is? I also add a test for empty-label case. From: Anand Jain generally if you use echo "test" > /sys/fs/btrfs//label it would introduce return char at the end and it can not be part of the label. The correct command is echo -n "test" > /sys/fs/btrfs//label This patch will check for this user error reproducer.sh: Reviewed-by: Wang Shilong Reviewed-by: David Sterba =============================================================================== #!/bin/bash TEST_DEV=/dev/vdb TEST_DIR=/home/sat/mnt umount /home/sat/mnt mkfs.btrfs -f $TEST_DEV UUID=$(btrfs fi show $TEST_DEV | head -1 | sed -e 's/.*uuid: \([-0-9a-z]*\)$/\1/') mount $TEST_DEV $TEST_DIR LABELFILE=/sys/fs/btrfs/$UUID/label echo "Test for empty label..." >&2 LINES="$(cat $LABELFILE | wc -l | awk '{print $1}')" RET=0 if [ $LINES -eq 0 ] ; then echo '[PASS] Trailing \n is removed correctly.' >&2 else echo '[FAIL] Trailing \n still exists.' >&2 RET=1 fi echo "Test for non-empty label..." >&2 echo testlabel >$LABELFILE LINES="$(cat $LABELFILE | wc -l | awk '{print $1}')" if [ $LINES -eq 1 ] ; then echo '[PASS] Trailing \n is removed correctly.' >&2 else echo '[FAIL] Trailing \n still exists.' >&2 RET=1 fi exit $RET =============================================================================== Signed-off-by: Anand Jain Signed-off-by: Satoru Takeuchi Reviewed-by: Satoru Takeuchi Tested-by: Satoru Takeuchi --- v6: fix empty-label case v5: tweak to be able to apply on the top of 402a0f4. add test program. v4: used memcpy and memset. Thanks David again v3: accepts review comments. Thanks David and Eric again v2: accepts review comments. Thanks Eric and Roman --- fs/btrfs/sysfs.c | 15 ++++++++++++--- 1 file changed, 12 insertions(+), 3 deletions(-) diff --git a/fs/btrfs/sysfs.c b/fs/btrfs/sysfs.c index df39458..68d1f63 100644 --- a/fs/btrfs/sysfs.c +++ b/fs/btrfs/sysfs.c @@ -363,7 +363,8 @@ static ssize_t btrfs_label_show(struct kobject *kobj, struct kobj_attribute *a, char *buf) { struct btrfs_fs_info *fs_info = to_fs_info(kobj); - return snprintf(buf, PAGE_SIZE, "%s\n", fs_info->super_copy->label); + char *label = fs_info->super_copy->label; + return snprintf(buf, PAGE_SIZE, label[0] ? "%s\n" : "%s", label); } static ssize_t btrfs_label_store(struct kobject *kobj, @@ -374,8 +375,15 @@ static ssize_t btrfs_label_store(struct kobject *kobj, struct btrfs_trans_handle *trans; struct btrfs_root *root = fs_info->fs_root; int ret; + size_t p_len; - if (len >= BTRFS_LABEL_SIZE) + /* + * p_len is the len until the first occurrence of either + * '\n' or '\0' + */ + p_len = strcspn(buf, "\n"); + + if (p_len >= BTRFS_LABEL_SIZE) return -EINVAL; trans = btrfs_start_transaction(root, 0); @@ -383,7 +391,8 @@ static ssize_t btrfs_label_store(struct kobject *kobj, return PTR_ERR(trans); spin_lock(&root->fs_info->super_lock); - strcpy(fs_info->super_copy->label, buf); + memset(fs_info->super_copy->label, 0, BTRFS_LABEL_SIZE); + memcpy(fs_info->super_copy->label, buf, p_len); spin_unlock(&root->fs_info->super_lock); ret = btrfs_commit_transaction(trans, root);