1 files changed, 116 insertions, 0 deletions

diff --git a/fs/incfs/main.c b/fs/incfs/main.c
new file mode 100644
index 000000000000..23cf3fefac97
--- /dev/null
+++ b/fs/incfs/main.c
@@ -0,0 +1,116 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Copyright 2018 Google LLC
+ */
+#include <linux/fs.h>
+#include <linux/init.h>
+#include <linux/module.h>
+
+#include <uapi/linux/incrementalfs.h>
+
+#include "vfs.h"
+
+#define INCFS_NODE_FEATURES "features"
+
+static struct file_system_type incfs_fs_type = {
+        .owner = THIS_MODULE,
+        .name = INCFS_NAME,
+        .mount = incfs_mount_fs,
+        .kill_sb = incfs_kill_sb,
+        .fs_flags = 0
+};
+
+static struct kobject *sysfs_root, *featurefs_root;
+
+static ssize_t supported(struct kobject *kobj,
+                         struct kobj_attribute *attr, char *buff)
+{
+        return snprintf(buff, PAGE_SIZE, "supported\n");
+}
+
+typedef ssize_t (*const attr_show)(struct kobject *kobj,
+                                   struct kobj_attribute *attr, char *buff);
+
+#define _DECLARE_FEATURE_FLAG(name)                                     \
+        static attr_show name##_show = supported;                       \
+        static struct kobj_attribute name##_attr = __ATTR_RO(name)
+
+#define DECLARE_FEATURE_FLAG(name) _DECLARE_FEATURE_FLAG(name)
+
+DECLARE_FEATURE_FLAG(corefs);
+DECLARE_FEATURE_FLAG(zstd);
+DECLARE_FEATURE_FLAG(v2);
+
+static struct attribute *attributes[] = {
+        &corefs_attr.attr,
+        &zstd_attr.attr,
+        &v2_attr.attr,
+        NULL,
+};
+
+static const struct attribute_group attr_group = {
+        .attrs = attributes,
+};
+
+static int __init init_sysfs(void)
+{
+        int res = 0;
+
+        sysfs_root = kobject_create_and_add(INCFS_NAME, fs_kobj);
+        if (!sysfs_root)
+                return -ENOMEM;
+
+        featurefs_root = kobject_create_and_add(INCFS_NODE_FEATURES,
+                                                sysfs_root);
+        if (!featurefs_root)
+                return -ENOMEM;
+
+        res = sysfs_create_group(featurefs_root, &attr_group);
+        if (res) {
+                kobject_put(sysfs_root);
+                sysfs_root = NULL;
+        }
+        return res;
+}
+
+static void cleanup_sysfs(void)
+{
+        if (featurefs_root) {
+                sysfs_remove_group(featurefs_root, &attr_group);
+                kobject_put(featurefs_root);
+                featurefs_root = NULL;
+        }
+
+        if (sysfs_root) {
+                kobject_put(sysfs_root);
+                sysfs_root = NULL;
+        }
+}
+
+static int __init init_incfs_module(void)
+{
+        int err = 0;
+
+        err = init_sysfs();
+        if (err)
+                return err;
+
+        err = register_filesystem(&incfs_fs_type);
+        if (err)
+                cleanup_sysfs();
+
+        return err;
+}
+
+static void __exit cleanup_incfs_module(void)
+{
+        cleanup_sysfs();
+        unregister_filesystem(&incfs_fs_type);
+}
+
+module_init(init_incfs_module);
+module_exit(cleanup_incfs_module);
+
+MODULE_LICENSE("GPL v2");
+MODULE_AUTHOR("Eugene Zemtsov <ezemtsov@google.com>");
+MODULE_DESCRIPTION("Incremental File System");