Eric Lee / smarc-fsl-linux-kernel

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fs/incfs/main.c 2 KB
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d7d243b52   Eric Lee   SMARC-iMX8MQ Linu... 
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  // 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 corefs_show(struct kobject *kobj,
  			  struct kobj_attribute *attr, char *buff)
  {
  	return snprintf(buff, PAGE_SIZE, "supported
  ");
  }
  
  static struct kobj_attribute corefs_attr = __ATTR_RO(corefs);
  
  static struct attribute *attributes[] = {
  	&corefs_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_IMPORT_NS(VFS_internal_I_am_really_a_filesystem_and_am_NOT_a_driver);
  MODULE_AUTHOR("Eugene Zemtsov <ezemtsov@google.com>");
  MODULE_DESCRIPTION("Incremental File System");