3 files changed, 188 insertions, 0 deletions

diff --git a/Documentation/ABI/testing/sysfs-fs-nilfs2 b/Documentation/ABI/testing/sysfs-fs-nilfs2
new file mode 100644
index 000000000000..71b4fd39f74d
--- /dev/null
+++ b/Documentation/ABI/testing/sysfs-fs-nilfs2
@@ -0,0 +1,14 @@
+
+What:           /sys/fs/nilfs2/features/revision
+Date:           April 2014
+Contact:        "Vyacheslav Dubeyko" <slava@dubeyko.com>
+Description:
+                Show current revision of NILFS file system driver.
+                This value informs about file system revision that
+                driver is ready to support.
+
+What:           /sys/fs/nilfs2/features/README
+Date:           April 2014
+Contact:        "Vyacheslav Dubeyko" <slava@dubeyko.com>
+Description:
+                Describe attributes of /sys/fs/nilfs2/features group.
diff --git a/fs/nilfs2/sysfs.c b/fs/nilfs2/sysfs.c
new file mode 100644
index 000000000000..41b8f7039657
--- /dev/null
+++ b/fs/nilfs2/sysfs.c
@@ -0,0 +1,113 @@
+/*
+ * sysfs.c - sysfs support implementation.
+ *
+ * Copyright (C) 2005-2014 Nippon Telegraph and Telephone Corporation.
+ * Copyright (C) 2014 HGST, Inc., a Western Digital Company.
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * Written by Vyacheslav Dubeyko <Vyacheslav.Dubeyko@hgst.com>
+ */
+
+#include <linux/kobject.h>
+
+#include "nilfs.h"
+#include "mdt.h"
+#include "sufile.h"
+#include "cpfile.h"
+#include "sysfs.h"
+
+/* /sys/fs/<nilfs>/ */
+static struct kset *nilfs_kset;
+
+#define NILFS_SHOW_TIME(time_t_val, buf) ({ \
+                struct tm res; \
+                int count = 0; \
+                time_to_tm(time_t_val, 0, &res); \
+                res.tm_year += 1900; \
+                res.tm_mon += 1; \
+                count = scnprintf(buf, PAGE_SIZE, \
+                                    "%ld-%.2d-%.2d %.2d:%.2d:%.2d\n", \
+                                    res.tm_year, res.tm_mon, res.tm_mday, \
+                                    res.tm_hour, res.tm_min, res.tm_sec);\
+                count; \
+})
+
+/************************************************************************
+ *                        NILFS feature attrs                           *
+ ************************************************************************/
+
+static ssize_t nilfs_feature_revision_show(struct kobject *kobj,
+                                            struct attribute *attr, char *buf)
+{
+        return snprintf(buf, PAGE_SIZE, "%d.%d\n",
+                        NILFS_CURRENT_REV, NILFS_MINOR_REV);
+}
+
+static const char features_readme_str[] =
+        "The features group contains attributes that describe NILFS file\n"
+        "system driver features.\n\n"
+        "(1) revision\n\tshow current revision of NILFS file system driver.\n";
+
+static ssize_t nilfs_feature_README_show(struct kobject *kobj,
+                                         struct attribute *attr,
+                                         char *buf)
+{
+        return snprintf(buf, PAGE_SIZE, features_readme_str);
+}
+
+NILFS_FEATURE_RO_ATTR(revision);
+NILFS_FEATURE_RO_ATTR(README);
+
+static struct attribute *nilfs_feature_attrs[] = {
+        NILFS_FEATURE_ATTR_LIST(revision),
+        NILFS_FEATURE_ATTR_LIST(README),
+        NULL,
+};
+
+static const struct attribute_group nilfs_feature_attr_group = {
+        .name = "features",
+        .attrs = nilfs_feature_attrs,
+};
+
+int __init nilfs_sysfs_init(void)
+{
+        int err;
+
+        nilfs_kset = kset_create_and_add(NILFS_ROOT_GROUP_NAME, NULL, fs_kobj);
+        if (!nilfs_kset) {
+                err = -ENOMEM;
+                printk(KERN_ERR "NILFS: unable to create sysfs entry: err %d\n",
+                        err);
+                goto failed_sysfs_init;
+        }
+
+        err = sysfs_create_group(&nilfs_kset->kobj, &nilfs_feature_attr_group);
+        if (unlikely(err)) {
+                printk(KERN_ERR "NILFS: unable to create feature group: err %d\n",
+                        err);
+                goto cleanup_sysfs_init;
+        }
+
+        return 0;
+
+cleanup_sysfs_init:
+        kset_unregister(nilfs_kset);
+
+failed_sysfs_init:
+        return err;
+}
+
+void nilfs_sysfs_exit(void)
+{
+        sysfs_remove_group(&nilfs_kset->kobj, &nilfs_feature_attr_group);
+        kset_unregister(nilfs_kset);
+}
diff --git a/fs/nilfs2/sysfs.h b/fs/nilfs2/sysfs.h
new file mode 100644
index 000000000000..0aed24661052
--- /dev/null
+++ b/fs/nilfs2/sysfs.h
@@ -0,0 +1,61 @@
+/*
+ * sysfs.h - sysfs support declarations.
+ *
+ * Copyright (C) 2005-2014 Nippon Telegraph and Telephone Corporation.
+ * Copyright (C) 2014 HGST, Inc., a Western Digital Company.
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * Written by Vyacheslav Dubeyko <Vyacheslav.Dubeyko@hgst.com>
+ */
+
+#ifndef _NILFS_SYSFS_H
+#define _NILFS_SYSFS_H
+
+#include <linux/sysfs.h>
+
+#define NILFS_ROOT_GROUP_NAME   "nilfs2"
+
+#define NILFS_COMMON_ATTR_STRUCT(name) \
+struct nilfs_##name##_attr { \
+        struct attribute attr; \
+        ssize_t (*show)(struct kobject *, struct attribute *, \
+                        char *); \
+        ssize_t (*store)(struct kobject *, struct attribute *, \
+                         const char *, size_t); \
+};
+
+NILFS_COMMON_ATTR_STRUCT(feature);
+
+#define NILFS_ATTR(type, name, mode, show, store) \
+        static struct nilfs_##type##_attr nilfs_##type##_attr_##name = \
+                __ATTR(name, mode, show, store)
+
+#define NILFS_INFO_ATTR(type, name) \
+        NILFS_ATTR(type, name, 0444, NULL, NULL)
+#define NILFS_RO_ATTR(type, name) \
+        NILFS_ATTR(type, name, 0444, nilfs_##type##_##name##_show, NULL)
+#define NILFS_RW_ATTR(type, name) \
+        NILFS_ATTR(type, name, 0644, \
+                    nilfs_##type##_##name##_show, \
+                    nilfs_##type##_##name##_store)
+
+#define NILFS_FEATURE_INFO_ATTR(name) \
+        NILFS_INFO_ATTR(feature, name)
+#define NILFS_FEATURE_RO_ATTR(name) \
+        NILFS_RO_ATTR(feature, name)
+#define NILFS_FEATURE_RW_ATTR(name) \
+        NILFS_RW_ATTR(feature, name)
+
+#define NILFS_FEATURE_ATTR_LIST(name) \
+        (&nilfs_feature_attr_##name.attr)
+
+#endif /* _NILFS_SYSFS_H */