From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from aserp2130.oracle.com ([141.146.126.79]:41240 "EHLO aserp2130.oracle.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727009AbeHFDMz (ORCPT ); Sun, 5 Aug 2018 23:12:55 -0400 Received: from pps.filterd (aserp2130.oracle.com [127.0.0.1]) by aserp2130.oracle.com (8.16.0.22/8.16.0.22) with SMTP id w7614aSv074202 for ; Mon, 6 Aug 2018 01:06:18 GMT Received: from userv0021.oracle.com (userv0021.oracle.com [156.151.31.71]) by aserp2130.oracle.com with ESMTP id 2kn1nctw48-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=OK) for ; Mon, 06 Aug 2018 01:06:18 +0000 Received: from aserv0122.oracle.com (aserv0122.oracle.com [141.146.126.236]) by userv0021.oracle.com (8.14.4/8.14.4) with ESMTP id w7616HRd019641 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-GCM-SHA384 bits=256 verify=OK) for ; Mon, 6 Aug 2018 01:06:17 GMT Received: from abhmp0012.oracle.com (abhmp0012.oracle.com [141.146.116.18]) by aserv0122.oracle.com (8.14.4/8.14.4) with ESMTP id w7616HFU030183 for ; Mon, 6 Aug 2018 01:06:17 GMT From: Anand Jain To: linux-btrfs@vger.kernel.org Subject: [PATCH] btrfs: introduce feature to forget a btrfs device Date: Mon, 6 Aug 2018 09:09:48 +0800 Message-Id: <20180806010949.26915-2-anand.jain@oracle.com> In-Reply-To: <20180806010949.26915-1-anand.jain@oracle.com> References: <20180806010949.26915-1-anand.jain@oracle.com> Sender: linux-btrfs-owner@vger.kernel.org List-ID: 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 --- 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 67de3c0fc85b..470a32af474e 100644 --- a/fs/btrfs/super.c +++ b/fs/btrfs/super.c @@ -2244,6 +2244,9 @@ 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 8844904f9009..cd54a926141a 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); + 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 049619176831..1602b5faa7e7 100644 --- a/fs/btrfs/volumes.h +++ b/fs/btrfs/volumes.h @@ -405,6 +405,7 @@ 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 -- 2.7.0