1 files changed, 7 insertions, 124 deletions

diff --git a/fs/btrfs/sysfs.c b/fs/btrfs/sysfs.c
index 0d14570c8bc2..c5bb1c7eac6a 100644
--- a/fs/btrfs/sysfs.c
+++ b/fs/btrfs/sysfs.c
@@ -83,8 +83,7 @@ struct raid_kobject {
 #define BTRFS_FEAT_ATTR(_name, _feature_set, _feature_prefix, _feature_bit)  \
 static struct btrfs_feature_attr btrfs_attr_features_##_name = {	     \
 	.kobj_attr = __INIT_KOBJ_ATTR(_name, S_IRUGO,			     \
-				      btrfs_feature_attr_show,		     \
-				      btrfs_feature_attr_store),	     \
+				      btrfs_feature_attr_show, NULL),	     \
 	.feature_set	= _feature_set,					     \
 	.feature_bit	= _feature_prefix ##_## _feature_bit,		     \
 }
@@ -130,130 +129,20 @@ static u64 get_features(struct btrfs_fs_info *fs_info,
 		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:
-		btrfs_warn(NULL, "sysfs: unknown feature set %d", fa->feature_set);
-		return 0;
-	}
-
-	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) {
 		u64 features = get_features(fs_info, fa->feature_set);
 		if (features & fa->feature_bit)
 			val = 1;
-	} else
-		val = can_modify_feature(fa);
-
-	return sysfs_emit(buf, "%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);
-	u64 features, set, clear;
-	unsigned long val;
-	int ret;
-
-	fs_info = to_fs_info(kobj);
-	if (!fs_info)
-		return -EPERM;
-
-	if (sb_rdonly(fs_info->sb))
-		return -EROFS;
-
-	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);
-
-	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);
-
-	/*
-	 * We don't want to do full transaction commit from inside sysfs
-	 */
-	set_bit(BTRFS_FS_NEED_TRANS_COMMIT, &fs_info->flags);
-	wake_up_process(fs_info->transaction_kthread);
-
-	return count;
+	return sysfs_emit(buf, "%d\n", val);
 }
 
 static umode_t btrfs_feature_visible(struct kobject *kobj,
@@ -269,9 +158,7 @@ static umode_t btrfs_feature_visible(struct kobject *kobj,
 		fa = attr_to_btrfs_feature_attr(attr);
 		features = get_features(fs_info, fa->feature_set);
 
-		if (can_modify_feature(fa))
-			mode |= S_IWUSR;
-		else if (!(features & fa->feature_bit))
+		if (!(features & fa->feature_bit))
 			mode = 0;
 	}
 
@@ -1336,7 +1223,7 @@ char *btrfs_get_mod_read_policy(void)
 	return read_policy;
 }
 
-/* Set perms to 0, disable /sys/module/btrfs/parameter/read_policy interface. */
+/* Set perms to 0, disable /sys/module/btrfs/parameters/read_policy interface. */
 module_param(read_policy, charp, 0);
 MODULE_PARM_DESC(read_policy,
 "Global read policy: pid (default), round-robin[:<min_contig_read>], devid[:<devid>]");
@@ -2359,9 +2246,7 @@ static ssize_t qgroup_enabled_show(struct kobject *qgroups_kobj,
 	struct btrfs_fs_info *fs_info = to_fs_info(qgroups_kobj->parent);
 	bool enabled;
 
-	spin_lock(&fs_info->qgroup_lock);
-	enabled = fs_info->qgroup_flags & BTRFS_QGROUP_STATUS_FLAG_ON;
-	spin_unlock(&fs_info->qgroup_lock);
+	enabled = test_bit(BTRFS_QGROUP_STATUS_BIT_ON, &fs_info->qgroup_flags);
 
 	return sysfs_emit(buf, "%d\n", enabled);
 }
@@ -2401,9 +2286,7 @@ static ssize_t qgroup_inconsistent_show(struct kobject *qgroups_kobj,
 	struct btrfs_fs_info *fs_info = to_fs_info(qgroups_kobj->parent);
 	bool inconsistent;
 
-	spin_lock(&fs_info->qgroup_lock);
-	inconsistent = (fs_info->qgroup_flags & BTRFS_QGROUP_STATUS_FLAG_INCONSISTENT);
-	spin_unlock(&fs_info->qgroup_lock);
+	inconsistent = test_bit(BTRFS_QGROUP_STATUS_BIT_INCONSISTENT, &fs_info->qgroup_flags);
 
 	return sysfs_emit(buf, "%d\n", inconsistent);
 }