From patchwork Sun Aug 5 10:40:01 2018 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Lu Fengqi X-Patchwork-Id: 10556103 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 C4E1A1708 for ; Sun, 5 Aug 2018 10:40:23 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id B763729941 for ; Sun, 5 Aug 2018 10:40:23 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id ABBB429944; Sun, 5 Aug 2018 10:40:23 +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 3B8392994B for ; Sun, 5 Aug 2018 10:40:23 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726371AbeHEMo3 (ORCPT ); Sun, 5 Aug 2018 08:44:29 -0400 Received: from mail.cn.fujitsu.com ([183.91.158.132]:52034 "EHLO heian.cn.fujitsu.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1726121AbeHEMo2 (ORCPT ); Sun, 5 Aug 2018 08:44:28 -0400 X-IronPort-AV: E=Sophos;i="5.43,368,1503331200"; d="scan'208";a="43083792" Received: from unknown (HELO cn.fujitsu.com) ([10.167.33.5]) by heian.cn.fujitsu.com with ESMTP; 05 Aug 2018 18:40:12 +0800 Received: from G08CNEXCHPEKD02.g08.fujitsu.local (unknown [10.167.33.83]) by cn.fujitsu.com (Postfix) with ESMTP id BDA4D4B6ADFC for ; Sun, 5 Aug 2018 18:40:10 +0800 (CST) Received: from fnst.localdomain (10.167.226.155) by G08CNEXCHPEKD02.g08.fujitsu.local (10.167.33.89) with Microsoft SMTP Server (TLS) id 14.3.399.0; Sun, 5 Aug 2018 18:40:13 +0800 From: Lu Fengqi To: Subject: [RFC PATCH 4/4] btrfs: undelete: Add the btrfs_ioctl_undelete Date: Sun, 5 Aug 2018 18:40:01 +0800 Message-ID: <20180805104001.5488-5-lufq.fnst@cn.fujitsu.com> X-Mailer: git-send-email 2.18.0 In-Reply-To: <20180805104001.5488-1-lufq.fnst@cn.fujitsu.com> References: <20180805104001.5488-1-lufq.fnst@cn.fujitsu.com> MIME-Version: 1.0 X-Originating-IP: [10.167.226.155] X-yoursite-MailScanner-ID: BDA4D4B6ADFC.A04DD 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 The function will traverse the root from the fs_info->dead_roots and try to call btrfs_undelete_subvolume() to recover them. 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 | 83 ++++++++++++++++++++++++++++++++++++++ include/uapi/linux/btrfs.h | 9 +++++ 2 files changed, 92 insertions(+) diff --git a/fs/btrfs/ioctl.c b/fs/btrfs/ioctl.c index 7a11c4f8e450..83b9839799d0 100644 --- a/fs/btrfs/ioctl.c +++ b/fs/btrfs/ioctl.c @@ -1980,6 +1980,87 @@ static int btrfs_undelete_subvolume(const struct path *parent, return ret; } +static int btrfs_ioctl_undelete(struct file *file, void __user *argp) +{ + struct btrfs_ioctl_undelete_args __user *uarg; + struct btrfs_ioctl_undelete_args *args; + struct inode *inode = file_inode(file); + struct btrfs_fs_info *fs_info = btrfs_sb(inode->i_sb); + struct btrfs_root *root, *tmp; + char *name; + u64 count = 0; + u64 objectid; + int err = 0, ret; + + /* copy search header and buffer size */ + uarg = (struct btrfs_ioctl_undelete_args __user *)argp; + args = memdup_user(uarg, sizeof(*args)); + if (IS_ERR(args)) + return PTR_ERR(args); + args->name[BTRFS_PATH_NAME_MAX] = '\0'; + + name = kzalloc(BTRFS_PATH_NAME_MAX + 1, GFP_KERNEL); + if (IS_ERR(name)) { + err = PTR_ERR(name); + goto free_args; + } + + if (!capable(CAP_SYS_ADMIN)) { + err = -EPERM; + goto free; + } + + err = mnt_want_write_file(file); + if (err) + goto free; + + /* 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); + + list_for_each_entry_safe(root, tmp, &fs_info->dead_roots, root_list) { + objectid = root->root_key.objectid; + snprintf(name, BTRFS_PATH_NAME_MAX, "%s%llu", args->name, + objectid); + ret = btrfs_undelete_subvolume(&file->f_path, root, name, + strlen(name)); + if (ret) + continue; + + /* + * Feel free to remove this root from dead_root list since we + * have recover it successfully. + */ + spin_lock(&fs_info->trans_lock); + list_del_init(&root->root_list); + spin_unlock(&fs_info->trans_lock); + + if ((count + 1) * sizeof(objectid) > args->buf_size) + continue; + + /* copy the subvolume id to user space */ + ret = copy_to_user(&uarg->buf[count], &objectid, + sizeof(objectid)); + if (ret) + err = -EFAULT; + count++; + } + + mutex_unlock(&fs_info->cleaner_mutex); + mnt_drop_write_file(file); + + /* copy the count to user space */ + if (copy_to_user(&uarg->count, &count, sizeof(count))) + err = -EFAULT; +free: + kfree(name); +free_args: + kfree(args); + return err; +} + static noinline int btrfs_ioctl_subvol_getflags(struct file *file, void __user *arg) { @@ -6089,6 +6170,8 @@ 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..25d030687b27 100644 --- a/include/uapi/linux/btrfs.h +++ b/include/uapi/linux/btrfs.h @@ -816,6 +816,13 @@ struct btrfs_ioctl_get_subvol_rootref_args { __u8 align[7]; }; +struct btrfs_ioctl_undelete_args { + char name[BTRFS_PATH_NAME_MAX + 1]; /* in - subvolume name prefix */ + __u64 buf_size; /* in - size of buffer */ + __u64 count; /* out - store number of recoverd subvolumes */ + __u64 buf[0]; /* out - store ids of recoverd subolumes */ +}; + /* Error codes as returned by the kernel */ enum btrfs_err_code { BTRFS_ERROR_DEV_RAID1_MIN_NOT_MET = 1, @@ -940,5 +947,7 @@ 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_undelete_args) #endif /* _UAPI_LINUX_BTRFS_H */