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=-7.7 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH, MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_PASS,URIBL_BLOCKED autolearn=ham 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 2230CC43441 for ; Wed, 14 Nov 2018 13:26:42 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id C7E76208E7 for ; Wed, 14 Nov 2018 13:26:41 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=oracle.com header.i=@oracle.com header.b="Vp32CbFt" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org C7E76208E7 Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=oracle.com Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-btrfs-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1732353AbeKNX3z (ORCPT ); Wed, 14 Nov 2018 18:29:55 -0500 Received: from userp2130.oracle.com ([156.151.31.86]:41884 "EHLO userp2130.oracle.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1728033AbeKNX3z (ORCPT ); Wed, 14 Nov 2018 18:29:55 -0500 Received: from pps.filterd (userp2130.oracle.com [127.0.0.1]) by userp2130.oracle.com (8.16.0.22/8.16.0.22) with SMTP id wAEDO0Vc162823; Wed, 14 Nov 2018 13:26:38 GMT DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=oracle.com; h=subject : to : cc : references : from : message-id : date : mime-version : in-reply-to : content-type : content-transfer-encoding; s=corp-2018-07-02; bh=44Wmjxfc7KUs09CnX+ZpGUwY0LoPuYAZSFmUkc4hTuA=; b=Vp32CbFtI93Xq+Hi5AImCj2KrbAFs4rhAb18vxaxfYAbsOMMPiDc3j1scQs81ZvJAHAd NKI29t/Lfhcl+dsLgzf7yRA30jQiiPnWNaShushUZV3voCi1+tKDjVAU7WurXMHykOoH 02WJOzntQ7hyzjPsRGxg/oLOtnLlHIpYE6Y3dj2khHbl8nI1cF/holTdMoquWSyEtwIA Ox6wTUOiYI4UVcUWAoWwTH7eWRewPWG7YJYt0pNTuNro0QksKJwtGhhd+iA2TFIORjq0 YTkFyslTgVtTKZgxhiiHm0ZKgbJJnN/6pEmjK+7v8JU0zGISu3PT9rC6fg5PJMyJKBAw OA== Received: from aserv0021.oracle.com (aserv0021.oracle.com [141.146.126.233]) by userp2130.oracle.com with ESMTP id 2nr7cs3d38-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=OK); Wed, 14 Nov 2018 13:26:38 +0000 Received: from userv0121.oracle.com (userv0121.oracle.com [156.151.31.72]) by aserv0021.oracle.com (8.14.4/8.14.4) with ESMTP id wAEDQVQk014338 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-GCM-SHA384 bits=256 verify=OK); Wed, 14 Nov 2018 13:26:32 GMT Received: from abhmp0013.oracle.com (abhmp0013.oracle.com [141.146.116.19]) by userv0121.oracle.com (8.14.4/8.13.8) with ESMTP id wAEDQVLh008142; Wed, 14 Nov 2018 13:26:31 GMT Received: from [192.168.0.120] (/202.156.138.221) by default (Oracle Beehive Gateway v4.0) with ESMTP ; Wed, 14 Nov 2018 05:26:31 -0800 Subject: Re: [PATCH] btrfs: introduce feature to forget a btrfs device To: fdmanana@gmail.com Cc: linux-btrfs References: <1542186768-22956-1-git-send-email-anand.jain@oracle.com> <1542186768-22956-2-git-send-email-anand.jain@oracle.com> From: Anand Jain Message-ID: <32cbf707-ce9a-2f4d-1279-2d3ef3459752@oracle.com> Date: Wed, 14 Nov 2018 21:26:40 +0800 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:52.0) Gecko/20100101 Thunderbird/52.9.1 MIME-Version: 1.0 In-Reply-To: Content-Type: text/plain; charset=utf-8; format=flowed Content-Language: en-US Content-Transfer-Encoding: 7bit X-Proofpoint-Virus-Version: vendor=nai engine=5900 definitions=9076 signatures=668683 X-Proofpoint-Spam-Details: rule=notspam policy=default score=0 suspectscore=3 malwarescore=0 phishscore=0 bulkscore=0 spamscore=0 mlxscore=0 mlxlogscore=999 adultscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.0.1-1810050000 definitions=main-1811140122 Sender: linux-btrfs-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-btrfs@vger.kernel.org On 11/14/2018 07:15 PM, Filipe Manana wrote: > On Wed, Nov 14, 2018 at 9:14 AM Anand Jain wrote: >> >> Support for a new command 'btrfs dev forget [dev]' is proposed here >> to undo the effects of 'btrfs dev scan [dev]'. For this purpose >> this patch proposes to use ioctl #5 as it was empty. >> IOW(BTRFS_IOCTL_MAGIC, 5, ..) >> This patch adds new ioctl BTRFS_IOC_FORGET_DEV which can be sent from >> the /dev/btrfs-control to forget one or all devices, (devices which are >> not mounted) from the btrfs kernel. >> >> The argument it takes is struct btrfs_ioctl_vol_args, and ::name can be >> set to specify the device path. And all unmounted devices can be removed >> from the kernel if no device path is provided. >> >> Again, the devices are removed only if the relevant fsid aren't mounted. >> >> This new cli can provide.. >> . Release of unwanted btrfs_fs_devices and btrfs_devices memory if the >> device is not going to be mounted. >> . Ability to mount the device in degraded mode when one of the other >> device is corrupted like in split brain raid1. >> . Running test cases which requires btrfs.ko-reload if the rootfs >> is btrfs. >> >> Signed-off-by: Anand Jain >> Reviewed-by: Nikolay Borisov >> --- >> fs/btrfs/super.c | 3 +++ >> fs/btrfs/volumes.c | 9 +++++++++ >> fs/btrfs/volumes.h | 1 + >> include/uapi/linux/btrfs.h | 2 ++ >> 4 files changed, 15 insertions(+) >> >> diff --git a/fs/btrfs/super.c b/fs/btrfs/super.c >> index 345c64d810d4..f99db6899004 100644 >> --- a/fs/btrfs/super.c >> +++ b/fs/btrfs/super.c >> @@ -2246,6 +2246,9 @@ static long btrfs_control_ioctl(struct file *file, unsigned int cmd, >> ret = PTR_ERR_OR_ZERO(device); >> mutex_unlock(&uuid_mutex); >> break; >> + case BTRFS_IOC_FORGET_DEV: >> + ret = btrfs_forget_devices(vol->name); >> + break; >> case BTRFS_IOC_DEVICES_READY: >> mutex_lock(&uuid_mutex); >> device = btrfs_scan_one_device(vol->name, FMODE_READ, >> diff --git a/fs/btrfs/volumes.c b/fs/btrfs/volumes.c >> index f435d397019e..e1365a122657 100644 >> --- a/fs/btrfs/volumes.c >> +++ b/fs/btrfs/volumes.c >> @@ -1208,6 +1208,15 @@ static int btrfs_read_disk_super(struct block_device *bdev, u64 bytenr, >> return 0; >> } >> >> +int btrfs_forget_devices(const char *path) >> +{ >> + mutex_lock(&uuid_mutex); >> + btrfs_free_stale_devices(strlen(path) ? path:NULL, NULL); > > One space before : and another one after it please. will fix. > Now the more important: don't use strlen, use strnlen. Some malicious > or sloppy user might have passed a non-null terminated string, you > don't want strlen to go past the limits of btrfs_ioctl_vol_args for > obvious reasons. Makes sense. Will fix. > Also, please, not just to make a maintainer's life easier, but current > and future reviewers, add the patch version to each patch's subject > and not just the cover letter. Also list (after ---) what changes > between each patch version in the patch itself and not the cover > letter. Sure. Thanks for the feedback. -Anand > V12, here we go. > >> + mutex_unlock(&uuid_mutex); >> + >> + return 0; >> +} >> + >> /* >> * Look for a btrfs signature on a device. This may be called out of the mount path >> * and we are not allowed to call set_blocksize during the scan. The superblock >> diff --git a/fs/btrfs/volumes.h b/fs/btrfs/volumes.h >> index aefce895e994..180297d04938 100644 >> --- a/fs/btrfs/volumes.h >> +++ b/fs/btrfs/volumes.h >> @@ -406,6 +406,7 @@ int btrfs_open_devices(struct btrfs_fs_devices *fs_devices, >> fmode_t flags, void *holder); >> struct btrfs_device *btrfs_scan_one_device(const char *path, >> fmode_t flags, void *holder); >> +int btrfs_forget_devices(const char *path); >> int btrfs_close_devices(struct btrfs_fs_devices *fs_devices); >> void btrfs_free_extra_devids(struct btrfs_fs_devices *fs_devices, int step); >> void btrfs_assign_next_active_device(struct btrfs_device *device, >> diff --git a/include/uapi/linux/btrfs.h b/include/uapi/linux/btrfs.h >> index 5ca1d21fc4a7..b1be7f828cb4 100644 >> --- a/include/uapi/linux/btrfs.h >> +++ b/include/uapi/linux/btrfs.h >> @@ -836,6 +836,8 @@ enum btrfs_err_code { >> struct btrfs_ioctl_vol_args) >> #define BTRFS_IOC_SCAN_DEV _IOW(BTRFS_IOCTL_MAGIC, 4, \ >> struct btrfs_ioctl_vol_args) >> +#define BTRFS_IOC_FORGET_DEV _IOW(BTRFS_IOCTL_MAGIC, 5, \ >> + struct btrfs_ioctl_vol_args) >> /* trans start and trans end are dangerous, and only for >> * use by applications that know how to avoid the >> * resulting deadlocks >> -- >> 1.8.3.1 >> > >