From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from cn.fujitsu.com ([59.151.112.132]:32737 "EHLO heian.cn.fujitsu.com" rhost-flags-OK-FAIL-OK-FAIL) by vger.kernel.org with ESMTP id S1754152AbbEOGri convert rfc822-to-8bit (ORCPT ); Fri, 15 May 2015 02:47:38 -0400 Received: from G08CNEXCHPEKD02.g08.fujitsu.local (localhost.localdomain [127.0.0.1]) by edo.cn.fujitsu.com (8.14.3/8.13.1) with ESMTP id t4F6kFNN004531 for ; Fri, 15 May 2015 14:46:15 +0800 Message-ID: <55559689.4090305@cn.fujitsu.com> Date: Fri, 15 May 2015 14:47:37 +0800 From: Qu Wenruo MIME-Version: 1.0 To: Subject: Re: [PATCH v9 9/9] btrfs: Use sb_want_write() to protect sysfs feature change. References: <1424048525-26274-1-git-send-email-quwenruo@cn.fujitsu.com> In-Reply-To: <1424048525-26274-1-git-send-email-quwenruo@cn.fujitsu.com> Content-Type: text/plain; charset="utf-8"; format=flowed Sender: linux-btrfs-owner@vger.kernel.org List-ID: Ping. Any comments? Other v7 patchset is reviewed by David. But I didn't find it in 4.1 merge windows. Is something wrong or we are waiting for the vfs patch merged first? Thanks, Qu -------- Original Message -------- Subject: [PATCH v9 9/9] btrfs: Use sb_want_write() to protect sysfs feature change. From: Qu Wenruo To: Date: 2015年02月16日 09:02 > Just like label change, use sb_want_write() to do a correct protection. > > Signed-off-by: Qu Wenruo > --- > v4: > Newly introduced. > v5: > Change to sb_want_write(). > v6: > Move sb_want_write() to the beginning of the function. > v7: > None > v8: > Move sb_want_write() after get fs_info. > v9: > Fix a unpaired sb_drop_write() in error handler. > --- > fs/btrfs/sysfs.c | 25 +++++++++++++++++-------- > 1 file changed, 17 insertions(+), 8 deletions(-) > > diff --git a/fs/btrfs/sysfs.c b/fs/btrfs/sysfs.c > index 7e548f7..19876ba 100644 > --- a/fs/btrfs/sysfs.c > +++ b/fs/btrfs/sysfs.c > @@ -121,10 +121,14 @@ static ssize_t btrfs_feature_attr_store(struct kobject *kobj, > if (!fs_info) > return -EPERM; > > - ret = kstrtoul(skip_spaces(buf), 0, &val); > + ret = sb_want_write(fs_info->sb); > if (ret) > return ret; > > + ret = kstrtoul(skip_spaces(buf), 0, &val); > + if (ret) > + goto out; > + > if (fa->feature_set == FEAT_COMPAT) { > set = BTRFS_FEATURE_COMPAT_SAFE_SET; > clear = BTRFS_FEATURE_COMPAT_SAFE_CLEAR; > @@ -141,22 +145,25 @@ static ssize_t btrfs_feature_attr_store(struct kobject *kobj, > /* Nothing to do */ > if ((val && (features & fa->feature_bit)) || > (!val && !(features & fa->feature_bit))) > - return count; > + goto out; > > if ((val && !(set & fa->feature_bit)) || > (!val && !(clear & fa->feature_bit))) { > btrfs_info(fs_info, > "%sabling feature %s on mounted fs is not supported.", > val ? "En" : "Dis", fa->kobj_attr.attr.name); > - return -EPERM; > + ret = -EPERM; > + goto out; > } > > btrfs_info(fs_info, "%s %s feature flag", > val ? "Setting" : "Clearing", fa->kobj_attr.attr.name); > > trans = btrfs_start_transaction(fs_info->fs_root, 0); > - if (IS_ERR(trans)) > - return PTR_ERR(trans); > + if (IS_ERR(trans)) { > + ret = PTR_ERR(trans); > + goto out; > + } > > spin_lock(&fs_info->super_lock); > features = get_features(fs_info, fa->feature_set); > @@ -168,10 +175,12 @@ static ssize_t btrfs_feature_attr_store(struct kobject *kobj, > spin_unlock(&fs_info->super_lock); > > ret = btrfs_commit_transaction(trans, fs_info->fs_root); > - if (ret) > - return ret; > > - return count; > +out: > + sb_drop_write(fs_info->sb); > + if (!ret) > + return count; > + return ret; > } > > static umode_t btrfs_feature_visible(struct kobject *kobj, >