From: David Sterba <dsterba@suse.cz>
Date: Fri, 23 Jan 2015 17:43:31 +0000 (+0100)
Subject: btrfs: add read-only check to sysfs handler of features
X-Git-Tag: v4.5.7~15
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=296f8da334a009ea2ec8112c2a1ac318872eff87;p=thirdparty%2Fkernel%2Fstable.git

btrfs: add read-only check to sysfs handler of features

commit ee6111386a1b304f8bf589d36810d53e3b27ee20 upstream.

We don't want to trigger the change on a read-only filesystem, similar
to what the label handler does.

Signed-off-by: David Sterba <dsterba@suse.cz>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---

diff --git a/fs/btrfs/sysfs.c b/fs/btrfs/sysfs.c
index 539e7b5e3f86a..6a6bb600b1ff4 100644
--- a/fs/btrfs/sysfs.c
+++ b/fs/btrfs/sysfs.c
@@ -120,6 +120,9 @@ static ssize_t btrfs_feature_attr_store(struct kobject *kobj,
 	if (!fs_info)
 		return -EPERM;
 
+	if (fs_info->sb->s_flags & MS_RDONLY)
+		return -EROFS;
+
 	ret = kstrtoul(skip_spaces(buf), 0, &val);
 	if (ret)
 		return ret;