From patchwork Wed Oct 16 19:44:22 2013 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Jeff Mahoney X-Patchwork-Id: 3057101 Return-Path: X-Original-To: patchwork-linux-btrfs@patchwork.kernel.org Delivered-To: patchwork-parsemail@patchwork2.web.kernel.org Received: from mail.kernel.org (mail.kernel.org [198.145.19.201]) by patchwork2.web.kernel.org (Postfix) with ESMTP id 02A79BF924 for ; Wed, 16 Oct 2013 19:44:34 +0000 (UTC) Received: from mail.kernel.org (localhost [127.0.0.1]) by mail.kernel.org (Postfix) with ESMTP id 280E3204BA for ; Wed, 16 Oct 2013 19:44:33 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 29B40204B9 for ; Wed, 16 Oct 2013 19:44:32 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1760641Ab3JPTo3 (ORCPT ); Wed, 16 Oct 2013 15:44:29 -0400 Received: from cantor2.suse.de ([195.135.220.15]:53644 "EHLO mx2.suse.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1760230Ab3JPTo2 (ORCPT ); Wed, 16 Oct 2013 15:44:28 -0400 Received: from relay1.suse.de (unknown [195.135.220.254]) by mx2.suse.de (Postfix) with ESMTP id 2952FA57B3 for ; Wed, 16 Oct 2013 21:44:27 +0200 (CEST) Message-ID: <525EEC96.4040306@suse.com> Date: Wed, 16 Oct 2013 15:44:22 -0400 From: Jeff Mahoney User-Agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10.8; rv:24.0) Gecko/20100101 Thunderbird/24.0.1 MIME-Version: 1.0 To: linux-btrfs Subject: [PATCH] btrfs: add ioctl to export size of global metadata reservation X-Enigmail-Version: 1.5.2 Sender: linux-btrfs-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-btrfs@vger.kernel.org X-Spam-Status: No, score=-7.4 required=5.0 tests=BAYES_00, RCVD_IN_DNSWL_HI, RP_MATCHES_RCVD, UNPARSEABLE_RELAY autolearn=unavailable version=3.3.1 X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on mail.kernel.org X-Virus-Scanned: ClamAV using ClamSMTP btrfs filesystem df output will show the size of the metadata space and how much of it is used, and the user assumes that the difference is all usable space. Since that's not actually the case due to the global metadata reservation, we should provide the full picture to the user. This patch adds an ioctl that exports the size of the global metadata reservation so that btrfs filesystem df can report it. Signed-off-by: Jeff Mahoney --- fs/btrfs/ioctl.c | 16 ++++++++++++++++ include/uapi/linux/btrfs.h | 1 + 2 files changed, 17 insertions(+) --- a/fs/btrfs/ioctl.c 2013-10-14 11:40:32.214512385 -0400 +++ b/fs/btrfs/ioctl.c 2013-10-16 14:58:52.464281753 -0400 @@ -3511,6 +3511,20 @@ out: return ret; } +static long btrfs_ioctl_global_rsv(struct btrfs_root *root, void __user *arg) +{ + struct btrfs_block_rsv *block_rsv = &root->fs_info->global_block_rsv; + u64 reserved; + + spin_lock(&block_rsv->lock); + reserved = block_rsv->reserved; + spin_unlock(&block_rsv->lock); + + if (arg && copy_to_user(arg, &reserved, sizeof(reserved))) + return -EFAULT; + return 0; +} + /* * there are many ways the trans_start and trans_end ioctls can lead * to deadlocks. They should only be used by applications that @@ -4721,6 +4735,8 @@ long btrfs_ioctl(struct file *file, unsi return btrfs_ioctl_logical_to_ino(root, argp); case BTRFS_IOC_SPACE_INFO: return btrfs_ioctl_space_info(root, argp); + case BTRFS_IOC_GLOBAL_RSV: + return btrfs_ioctl_global_rsv(root, argp); case BTRFS_IOC_SYNC: btrfs_sync_fs(file->f_dentry->d_sb, 1); return 0; --- a/include/uapi/linux/btrfs.h 2013-10-14 11:40:32.082514520 -0400 +++ b/include/uapi/linux/btrfs.h 2013-10-16 14:57:12.453792203 -0400 @@ -558,6 +558,7 @@ static inline char *btrfs_err_str(enum b #define BTRFS_IOC_DEFAULT_SUBVOL _IOW(BTRFS_IOCTL_MAGIC, 19, __u64) #define BTRFS_IOC_SPACE_INFO _IOWR(BTRFS_IOCTL_MAGIC, 20, \ struct btrfs_ioctl_space_args) +#define BTRFS_IOC_GLOBAL_RSV _IOR(BTRFS_IOCTL_MAGIC, 20, __u64) #define BTRFS_IOC_START_SYNC _IOR(BTRFS_IOCTL_MAGIC, 24, __u64) #define BTRFS_IOC_WAIT_SYNC _IOW(BTRFS_IOCTL_MAGIC, 22, __u64) #define BTRFS_IOC_SNAP_CREATE_V2 _IOW(BTRFS_IOCTL_MAGIC, 23, \