1 files changed, 33 insertions, 10 deletions

diff --git a/fs/nilfs2/sysfs.c b/fs/nilfs2/sysfs.c
index a5569b7f47a3..14868a3dd592 100644
--- a/fs/nilfs2/sysfs.c
+++ b/fs/nilfs2/sysfs.c
@@ -836,9 +836,15 @@ ssize_t nilfs_dev_revision_show(struct nilfs_dev_attr *attr,
 				struct the_nilfs *nilfs,
 				char *buf)
 {
-	struct nilfs_super_block **sbp = nilfs->ns_sbp;
-	u32 major = le32_to_cpu(sbp[0]->s_rev_level);
-	u16 minor = le16_to_cpu(sbp[0]->s_minor_rev_level);
+	struct nilfs_super_block *raw_sb;
+	u32 major;
+	u16 minor;
+
+	down_read(&nilfs->ns_sem);
+	raw_sb = nilfs->ns_sbp[0];
+	major = le32_to_cpu(raw_sb->s_rev_level);
+	minor = le16_to_cpu(raw_sb->s_minor_rev_level);
+	up_read(&nilfs->ns_sem);
 
 	return sysfs_emit(buf, "%d.%d\n", major, minor);
 }
@@ -856,8 +862,13 @@ ssize_t nilfs_dev_device_size_show(struct nilfs_dev_attr *attr,
 				    struct the_nilfs *nilfs,
 				    char *buf)
 {
-	struct nilfs_super_block **sbp = nilfs->ns_sbp;
-	u64 dev_size = le64_to_cpu(sbp[0]->s_dev_size);
+	struct nilfs_super_block *raw_sb;
+	u64 dev_size;
+
+	down_read(&nilfs->ns_sem);
+	raw_sb = nilfs->ns_sbp[0];
+	dev_size = le64_to_cpu(raw_sb->s_dev_size);
+	up_read(&nilfs->ns_sem);
 
 	return sysfs_emit(buf, "%llu\n", dev_size);
 }
@@ -879,9 +890,15 @@ ssize_t nilfs_dev_uuid_show(struct nilfs_dev_attr *attr,
 			    struct the_nilfs *nilfs,
 			    char *buf)
 {
-	struct nilfs_super_block **sbp = nilfs->ns_sbp;
+	struct nilfs_super_block *raw_sb;
+	ssize_t len;
 
-	return sysfs_emit(buf, "%pUb\n", sbp[0]->s_uuid);
+	down_read(&nilfs->ns_sem);
+	raw_sb = nilfs->ns_sbp[0];
+	len = sysfs_emit(buf, "%pUb\n", raw_sb->s_uuid);
+	up_read(&nilfs->ns_sem);
+
+	return len;
 }
 
 static
@@ -889,10 +906,16 @@ ssize_t nilfs_dev_volume_name_show(struct nilfs_dev_attr *attr,
 				    struct the_nilfs *nilfs,
 				    char *buf)
 {
-	struct nilfs_super_block **sbp = nilfs->ns_sbp;
+	struct nilfs_super_block *raw_sb;
+	ssize_t len;
+
+	down_read(&nilfs->ns_sem);
+	raw_sb = nilfs->ns_sbp[0];
+	len = scnprintf(buf, sizeof(raw_sb->s_volume_name), "%s\n",
+			raw_sb->s_volume_name);
+	up_read(&nilfs->ns_sem);
 
-	return scnprintf(buf, sizeof(sbp[0]->s_volume_name), "%s\n",
-			 sbp[0]->s_volume_name);
+	return len;
 }
 
 static const char dev_readme_str[] =