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Tue, 14 Jan 2020 05:15:37 +0000 Received: from pps.filterd (aserp3030.oracle.com [127.0.0.1]) by aserp3030.oracle.com (8.16.0.27/8.16.0.27) with SMTP id 00E5EIT7187627; Tue, 14 Jan 2020 05:15:36 GMT Received: from userv0121.oracle.com (userv0121.oracle.com [156.151.31.72]) by aserp3030.oracle.com with ESMTP id 2xh2tn2p74-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=OK); Tue, 14 Jan 2020 05:15:36 +0000 Received: from abhmp0019.oracle.com (abhmp0019.oracle.com [141.146.116.25]) by userv0121.oracle.com (8.14.4/8.13.8) with ESMTP id 00E5FZ5Z017119; Tue, 14 Jan 2020 05:15:35 GMT Received: from [10.190.130.61] (/192.188.170.109) by default (Oracle Beehive Gateway v4.0) with ESMTP ; Mon, 13 Jan 2020 21:15:35 -0800 Subject: Re: [PATCH 1/2] btrfs: open code log helpers in device_list_add() To: dsterba@suse.cz, linux-btrfs@vger.kernel.org References: <20200110090555.7049-1-anand.jain@oracle.com> <20200110164212.GQ3929@twin.jikos.cz> <20200113162521.GW3929@twin.jikos.cz> From: Anand Jain Message-ID: <01be0d25-e7e6-663e-3e49-82a248e7cc1e@oracle.com> Date: Tue, 14 Jan 2020 13:15:31 +0800 User-Agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10.15; rv:52.0) Gecko/20100101 Thunderbird/52.9.1 MIME-Version: 1.0 In-Reply-To: <20200113162521.GW3929@twin.jikos.cz> Content-Type: text/plain; charset=utf-8; format=flowed Content-Language: en-US Content-Transfer-Encoding: 7bit X-Proofpoint-Virus-Version: vendor=nai engine=6000 definitions=9499 signatures=668685 X-Proofpoint-Spam-Details: rule=notspam policy=default score=0 suspectscore=0 malwarescore=0 phishscore=0 bulkscore=0 spamscore=0 mlxscore=0 mlxlogscore=999 adultscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.0.1-1911140001 definitions=main-2001140045 X-Proofpoint-Virus-Version: vendor=nai engine=6000 definitions=9499 signatures=668685 X-Proofpoint-Spam-Details: rule=notspam policy=default score=0 priorityscore=1501 malwarescore=0 suspectscore=0 phishscore=0 bulkscore=0 spamscore=0 clxscore=1015 lowpriorityscore=0 mlxscore=0 impostorscore=0 mlxlogscore=999 adultscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.0.1-1911140001 definitions=main-2001140045 Sender: linux-btrfs-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-btrfs@vger.kernel.org On 14/1/20 12:25 AM, David Sterba wrote: > On Sat, Jan 11, 2020 at 07:41:51AM +0800, Anand Jain wrote: >>>> if (device->bdev != path_bdev) { >>>> bdput(path_bdev); >>>> mutex_unlock(&fs_devices->device_list_mutex); >>>> - btrfs_warn_in_rcu(device->fs_info, >>>> - "duplicate device fsid:devid for %pU:%llu old:%s new:%s", >>>> + rcu_read_lock(); >>>> + printk_ratelimited( >>> >>> Avoiding fs_info here is correct but we don't want to use raw printk or >>> printk_ratelimited anywhere. >>> >> >> I think I discussed this a long time back, that we should rather pass >> fs_devices in btrfs_warn_in_rcu(). >> >> I am ok to make such a change, are you ok? > > No, this does not sound right at all. Why should be btrfs_warn_in_rcu > special from the other message callbacks? We need to fix one context, so > let's find something less hacky. > >> Or I wonder if there is >> any other way? > > We could add a fs_info stub that will get recognized in btrfs_printk. > Eg. > > #define NO_FS_INFO ((void*)0x1) > > btrfs_printk() { > > if (fs_info == NULL) > devname = ""; > else if (fs_info == NO_FS_INFO) > devname = "..."; > else > devname = fs_info->sb->sb_id; > Yeah it makes sense to me. Patches sent. Thanks, Anand