From patchwork Fri Nov 15 20:34:01 2013 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Jeff Mahoney X-Patchwork-Id: 3189691 Return-Path: X-Original-To: patchwork-linux-btrfs@patchwork.kernel.org Delivered-To: patchwork-parsemail@patchwork1.web.kernel.org Received: from mail.kernel.org (mail.kernel.org [198.145.19.201]) by patchwork1.web.kernel.org (Postfix) with ESMTP id A45DA9F432 for ; Fri, 15 Nov 2013 20:36:37 +0000 (UTC) Received: from mail.kernel.org (localhost [127.0.0.1]) by mail.kernel.org (Postfix) with ESMTP id B0FCE207A3 for ; Fri, 15 Nov 2013 20:36:36 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 9F7D520598 for ; Fri, 15 Nov 2013 20:36:35 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753026Ab3KOUgc (ORCPT ); Fri, 15 Nov 2013 15:36:32 -0500 Received: from cantor2.suse.de ([195.135.220.15]:57259 "EHLO mx2.suse.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751719Ab3KOUgQ (ORCPT ); Fri, 15 Nov 2013 15:36:16 -0500 Received: from relay2.suse.de (unknown [195.135.220.254]) by mx2.suse.de (Postfix) with ESMTP id 28F2CA7995; Fri, 15 Nov 2013 21:36:15 +0100 (CET) Message-Id: <20131115203546.274225680@suse.com> User-Agent: quilt/0.60-5.1.1 Date: Fri, 15 Nov 2013 15:34:01 -0500 From: Jeff Mahoney To: linux-btrfs@vger.kernel.org Cc: Josef Bacik Subject: [PATCH 07/13] btrfs: add ability to change features via sysfs References: <20131115203354.082181444@suse.com> Content-Disposition: inline; filename=patches.suse/btrfs-add-ability-to-change-features-via-sysfs Sender: linux-btrfs-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-btrfs@vger.kernel.org X-Spam-Status: No, score=-6.9 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 This patch adds the ability to change (set/clear) features while the file system is mounted. A bitmask is added for each feature set for the support to set and clear the bits. A message indicating which bit has been set or cleared is issued when it's been changed and also when permission or support for a particular bit has been denied. Since the the attributes can now be writable, we need to introduce another struct attribute to hold the different permissions. If neither set or clear is supported, the file will have 0444 permissions. If either set or clear is supported, the file will have 0644 permissions and the store handler will filter out the write based on the bitmask. Signed-off-by: Jeff Mahoney --- fs/btrfs/sysfs.c | 118 +++++++++++++++++++++++++++++++++++++++++++++++++++++-- fs/btrfs/sysfs.h | 3 - 2 files changed, 117 insertions(+), 4 deletions(-) -- To unsubscribe from this list: send the line "unsubscribe linux-btrfs" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html --- a/fs/btrfs/sysfs.c 2013-10-21 16:10:01.076018741 -0400 +++ b/fs/btrfs/sysfs.c 2013-10-21 16:10:01.456010390 -0400 @@ -43,21 +43,131 @@ static u64 get_features(struct btrfs_fs_ return btrfs_super_incompat_flags(disk_super); } +static void set_features(struct btrfs_fs_info *fs_info, + enum btrfs_feature_set set, u64 features) +{ + struct btrfs_super_block *disk_super = fs_info->super_copy; + if (set == FEAT_COMPAT) + btrfs_set_super_compat_flags(disk_super, features); + else if (set == FEAT_COMPAT_RO) + btrfs_set_super_compat_ro_flags(disk_super, features); + else + btrfs_set_super_incompat_flags(disk_super, features); +} + +static int can_modify_feature(struct btrfs_feature_attr *fa) +{ + int val = 0; + u64 set, clear; + switch (fa->feature_set) { + case FEAT_COMPAT: + set = BTRFS_FEATURE_COMPAT_SAFE_SET; + clear = BTRFS_FEATURE_COMPAT_SAFE_CLEAR; + break; + case FEAT_COMPAT_RO: + set = BTRFS_FEATURE_COMPAT_RO_SAFE_SET; + clear = BTRFS_FEATURE_COMPAT_RO_SAFE_CLEAR; + break; + case FEAT_INCOMPAT: + set = BTRFS_FEATURE_INCOMPAT_SAFE_SET; + clear = BTRFS_FEATURE_INCOMPAT_SAFE_CLEAR; + break; + default: + BUG(); + } + + if (set & fa->feature_bit) + val |= 1; + if (clear & fa->feature_bit) + val |= 2; + + return val; +} + static ssize_t btrfs_feature_attr_show(struct kobject *kobj, struct kobj_attribute *a, char *buf) { int val = 0; struct btrfs_fs_info *fs_info = to_fs_info(kobj); + struct btrfs_feature_attr *fa = to_btrfs_feature_attr(a); if (fs_info) { - struct btrfs_feature_attr *fa = to_btrfs_feature_attr(a); u64 features = get_features(fs_info, fa->feature_set); if (features & fa->feature_bit) val = 1; - } + } else + val = can_modify_feature(fa); return snprintf(buf, PAGE_SIZE, "%d\n", val); } +static ssize_t btrfs_feature_attr_store(struct kobject *kobj, + struct kobj_attribute *a, + const char *buf, size_t count) +{ + struct btrfs_fs_info *fs_info; + struct btrfs_feature_attr *fa = to_btrfs_feature_attr(a); + struct btrfs_trans_handle *trans; + u64 features, set, clear; + unsigned long val; + int ret; + + fs_info = to_fs_info(kobj); + if (!fs_info) + return -EPERM; + + ret = kstrtoul(skip_spaces(buf), 0, &val); + if (ret) + return ret; + + if (fa->feature_set == FEAT_COMPAT) { + set = BTRFS_FEATURE_COMPAT_SAFE_SET; + clear = BTRFS_FEATURE_COMPAT_SAFE_CLEAR; + } else if (fa->feature_set == FEAT_COMPAT_RO) { + set = BTRFS_FEATURE_COMPAT_RO_SAFE_SET; + clear = BTRFS_FEATURE_COMPAT_RO_SAFE_CLEAR; + } else { + set = BTRFS_FEATURE_INCOMPAT_SAFE_SET; + clear = BTRFS_FEATURE_INCOMPAT_SAFE_CLEAR; + } + + features = get_features(fs_info, fa->feature_set); + + /* Nothing to do */ + if ((val && (features & fa->feature_bit)) || + (!val && !(features & fa->feature_bit))) + return count; + + if ((val && !(set & fa->feature_bit)) || + (!val && !(clear & fa->feature_bit))) { + btrfs_info(fs_info, + "%sabling feature %s on mounted fs is not supported.", + val ? "En" : "Dis", fa->kobj_attr.attr.name); + return -EPERM; + } + + btrfs_info(fs_info, "%s %s feature flag", + val ? "Setting" : "Clearing", fa->kobj_attr.attr.name); + + trans = btrfs_start_transaction(fs_info->fs_root, 1); + if (IS_ERR(trans)) + return PTR_ERR(trans); + + spin_lock(&fs_info->super_lock); + features = get_features(fs_info, fa->feature_set); + if (val) + features |= fa->feature_bit; + else + features &= ~fa->feature_bit; + set_features(fs_info, fa->feature_set, features); + spin_unlock(&fs_info->super_lock); + + ret = btrfs_commit_transaction(trans, fs_info->fs_root); + if (ret) + return ret; + + return count; +} + static umode_t btrfs_feature_visible(struct kobject *kobj, struct attribute *attr, int unused) { @@ -71,7 +181,9 @@ static umode_t btrfs_feature_visible(str fa = attr_to_btrfs_feature_attr(attr); features = get_features(fs_info, fa->feature_set); - if (!(features & fa->feature_bit)) + if (can_modify_feature(fa)) + mode |= S_IWUSR; + else if (!(features & fa->feature_bit)) mode = 0; } --- a/fs/btrfs/sysfs.h 2013-10-21 16:10:00.216037635 -0400 +++ b/fs/btrfs/sysfs.h 2013-10-21 16:10:01.460010303 -0400 @@ -31,7 +31,8 @@ struct btrfs_feature_attr { #define BTRFS_FEAT_ATTR(_name, _feature_set, _prefix, _feature_bit) \ static struct btrfs_feature_attr btrfs_attr_##_name = { \ .kobj_attr = __INIT_KOBJ_ATTR(_name, S_IRUGO, \ - btrfs_feature_attr_show, NULL), \ + btrfs_feature_attr_show, \ + btrfs_feature_attr_store), \ .feature_set = _feature_set, \ .feature_bit = _prefix ##_## _feature_bit, \ }