From patchwork Tue Sep 11 11:29:03 2018 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Lu Fengqi X-Patchwork-Id: 10595523 Return-Path: Received: from mail.wl.linuxfoundation.org (pdx-wl-mail.web.codeaurora.org [172.30.200.125]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id 8D45514BD for ; Tue, 11 Sep 2018 11:29:18 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 7C47F28CFB for ; Tue, 11 Sep 2018 11:29:18 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id 7092C28F2F; Tue, 11 Sep 2018 11:29:18 +0000 (UTC) X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on pdx-wl-mail.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-7.9 required=2.0 tests=BAYES_00,MAILING_LIST_MULTI, RCVD_IN_DNSWL_HI autolearn=ham version=3.3.1 Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 1005828CFB for ; Tue, 11 Sep 2018 11:29:18 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727010AbeIKQ2K (ORCPT ); Tue, 11 Sep 2018 12:28:10 -0400 Received: from mail.cn.fujitsu.com ([183.91.158.132]:23627 "EHLO heian.cn.fujitsu.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1726881AbeIKQ2K (ORCPT ); Tue, 11 Sep 2018 12:28:10 -0400 X-IronPort-AV: E=Sophos;i="5.43,368,1503331200"; d="scan'208";a="44777959" Received: from unknown (HELO cn.fujitsu.com) ([10.167.33.5]) by heian.cn.fujitsu.com with ESMTP; 11 Sep 2018 19:29:12 +0800 Received: from G08CNEXCHPEKD01.g08.fujitsu.local (unknown [10.167.33.80]) by cn.fujitsu.com (Postfix) with ESMTP id 99AFA4B6AE13 for ; Tue, 11 Sep 2018 19:29:12 +0800 (CST) Received: from fnst.localdomain (10.167.226.155) by G08CNEXCHPEKD01.g08.fujitsu.local (10.167.33.89) with Microsoft SMTP Server (TLS) id 14.3.408.0; Tue, 11 Sep 2018 19:29:16 +0800 From: Lu Fengqi To: Subject: [RFC PATCH v2 4/4] btrfs: undelete: Add BTRFS_IOCTL_SUBVOL_UNDELETE ioctl Date: Tue, 11 Sep 2018 19:29:03 +0800 Message-ID: <20180911112903.25985-5-lufq.fnst@cn.fujitsu.com> X-Mailer: git-send-email 2.18.0 In-Reply-To: <20180911112903.25985-1-lufq.fnst@cn.fujitsu.com> References: <20180911112903.25985-1-lufq.fnst@cn.fujitsu.com> MIME-Version: 1.0 X-Originating-IP: [10.167.226.155] X-yoursite-MailScanner-ID: 99AFA4B6AE13.AE3ED X-yoursite-MailScanner: Found to be clean X-yoursite-MailScanner-From: lufq.fnst@cn.fujitsu.com Sender: linux-btrfs-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-btrfs@vger.kernel.org X-Virus-Scanned: ClamAV using ClamSMTP This ioctl will provide user the ability to recover the subvolume of the given id to the given directory. Note: It will lock fs_info->cleaner_mutex to keep the cleaner kthread from deleting the subvolume which we want to recover. Signed-off-by: Lu Fengqi --- fs/btrfs/ioctl.c | 64 ++++++++++++++++++++++++++++++++++++++ include/uapi/linux/btrfs.h | 7 +++++ 2 files changed, 71 insertions(+) diff --git a/fs/btrfs/ioctl.c b/fs/btrfs/ioctl.c index f088dea53c16..3ddf6e1c117b 100644 --- a/fs/btrfs/ioctl.c +++ b/fs/btrfs/ioctl.c @@ -1993,6 +1993,68 @@ static int btrfs_undelete_subvolume(struct btrfs_root *root, return ret; } +static int btrfs_ioctl_undelete(struct file *file, void __user *argp) +{ + struct btrfs_ioctl_subvol_undelete_args *args; + struct inode *inode = file_inode(file); + struct btrfs_fs_info *fs_info = btrfs_sb(inode->i_sb); + struct btrfs_root *root; + int ret = 0; + + if (!S_ISDIR(inode->i_mode)) + return -ENOTDIR; + + args = memdup_user(argp, sizeof(*args)); + if (IS_ERR(args)) + return PTR_ERR(args); + + args->name[BTRFS_PATH_NAME_MAX] = '\0'; + + if (!capable(CAP_SYS_ADMIN)) { + ret = -EPERM; + goto free; + } + + ret = mnt_want_write_file(file); + if (ret) + goto free; + + ret = -ENOENT; + spin_lock(&fs_info->trans_lock); + list_for_each_entry(root, &fs_info->dead_roots, root_list) { + if (root->root_key.objectid == args->subvol_id) { + list_del_init(&root->root_list); + ret = 0; + break; + } + } + spin_unlock(&fs_info->trans_lock); + if (ret) + goto drop_write; + + /* + * Lock cleaner_mutex to prevent the cleaner kthread from deleting the + * subvolume we want to recover so that we can perform the next rescue + * in a relaxed manner. + */ + mutex_lock(&fs_info->cleaner_mutex); + + ret = btrfs_undelete_subvolume(root, file->f_path.dentry, args->name, + strlen(args->name)); + if (ret) { + btrfs_add_dead_root(root); + goto unlock; + } + +unlock: + mutex_unlock(&fs_info->cleaner_mutex); +drop_write: + mnt_drop_write_file(file); +free: + kfree(args); + return ret; +} + static noinline int btrfs_ioctl_subvol_getflags(struct file *file, void __user *arg) { @@ -6118,6 +6180,8 @@ long btrfs_ioctl(struct file *file, unsigned int return btrfs_ioctl_get_subvol_rootref(file, argp); case BTRFS_IOC_INO_LOOKUP_USER: return btrfs_ioctl_ino_lookup_user(file, argp); + case BTRFS_IOC_SUBVOL_UNDELETE: + return btrfs_ioctl_undelete(file, argp); } return -ENOTTY; diff --git a/include/uapi/linux/btrfs.h b/include/uapi/linux/btrfs.h index 5ca1d21fc4a7..e6d3c8e24bb8 100644 --- a/include/uapi/linux/btrfs.h +++ b/include/uapi/linux/btrfs.h @@ -816,6 +816,11 @@ struct btrfs_ioctl_get_subvol_rootref_args { __u8 align[7]; }; +struct btrfs_ioctl_subvol_undelete_args { + __u64 subvol_id; + char name[BTRFS_PATH_NAME_MAX + 1]; +}; + /* Error codes as returned by the kernel */ enum btrfs_err_code { BTRFS_ERROR_DEV_RAID1_MIN_NOT_MET = 1, @@ -940,5 +945,7 @@ enum btrfs_err_code { struct btrfs_ioctl_get_subvol_rootref_args) #define BTRFS_IOC_INO_LOOKUP_USER _IOWR(BTRFS_IOCTL_MAGIC, 62, \ struct btrfs_ioctl_ino_lookup_user_args) +#define BTRFS_IOC_SUBVOL_UNDELETE _IOWR(BTRFS_IOCTL_MAGIC, 63, \ + struct btrfs_ioctl_subvol_undelete_args) #endif /* _UAPI_LINUX_BTRFS_H */