/*
   * Copyright (C) 2012
   * Sachin Bhamare <sbhamare@panasas.com>
   * Boaz Harrosh <bharrosh@panasas.com>
   *
   * This file is part of exofs.
   *
   * exofs is free software; you can redistribute it and/or modify
   * it under the terms of the GNU General Public License 2 as published by
   * the Free Software Foundation.
   *
   * exofs 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.
   *
   * You should have received a copy of the GNU General Public License
   * along with exofs; if not, write to the:
   *	Free Software Foundation <licensing@fsf.org>
   */
  
  #include <linux/kobject.h>
  #include <linux/device.h>
  
  #include "exofs.h"
  
  struct odev_attr {
  	struct attribute attr;
  	ssize_t (*show)(struct exofs_dev *, char *);
  	ssize_t (*store)(struct exofs_dev *, const char *, size_t);
  };
  
  static ssize_t odev_attr_show(struct kobject *kobj, struct attribute *attr,
  		char *buf)
  {
  	struct exofs_dev *edp = container_of(kobj, struct exofs_dev, ed_kobj);
  	struct odev_attr *a = container_of(attr, struct odev_attr, attr);
  
  	return a->show ? a->show(edp, buf) : 0;
  }
  
  static ssize_t odev_attr_store(struct kobject *kobj, struct attribute *attr,
  		const char *buf, size_t len)
  {
  	struct exofs_dev *edp = container_of(kobj, struct exofs_dev, ed_kobj);
  	struct odev_attr *a = container_of(attr, struct odev_attr, attr);
  
  	return a->store ? a->store(edp, buf, len) : len;
  }
  
  static const struct sysfs_ops odev_attr_ops = {
  	.show  = odev_attr_show,
  	.store = odev_attr_store,
  };
  
  
  static struct kset *exofs_kset;
  
  static ssize_t osdname_show(struct exofs_dev *edp, char *buf)
  {
  	struct osd_dev *odev = edp->ored.od;
  	const struct osd_dev_info *odi = osduld_device_info(odev);
  
  	return snprintf(buf, odi->osdname_len + 1, "%s", odi->osdname);
  }
  
  static ssize_t systemid_show(struct exofs_dev *edp, char *buf)
  {
  	struct osd_dev *odev = edp->ored.od;
  	const struct osd_dev_info *odi = osduld_device_info(odev);
  
  	memcpy(buf, odi->systemid, odi->systemid_len);
  	return odi->systemid_len;
  }
  
  static ssize_t uri_show(struct exofs_dev *edp, char *buf)
  {
  	return snprintf(buf, edp->urilen, "%s", edp->uri);
  }
  
  static ssize_t uri_store(struct exofs_dev *edp, const char *buf, size_t len)
  {
  	uint8_t *new_uri;
  
  	edp->urilen = strlen(buf) + 1;
  	new_uri = krealloc(edp->uri, edp->urilen, GFP_KERNEL);
  	if (new_uri == NULL)
  		return -ENOMEM;
  	edp->uri = new_uri;
  	strncpy(edp->uri, buf, edp->urilen);
  	return edp->urilen;
  }
  
  #define OSD_ATTR(name, mode, show, store) \
  	static struct odev_attr odev_attr_##name = \
  					__ATTR(name, mode, show, store)
  
  OSD_ATTR(osdname, S_IRUGO, osdname_show, NULL);
  OSD_ATTR(systemid, S_IRUGO, systemid_show, NULL);
  OSD_ATTR(uri, S_IRWXU, uri_show, uri_store);
  
  static struct attribute *odev_attrs[] = {
  	&odev_attr_osdname.attr,
  	&odev_attr_systemid.attr,
  	&odev_attr_uri.attr,
  	NULL,
  };
  
  static struct kobj_type odev_ktype = {
  	.default_attrs	= odev_attrs,
  	.sysfs_ops	= &odev_attr_ops,
  };
  
  static struct kobj_type uuid_ktype = {
  };
  
  void exofs_sysfs_dbg_print(void)
  {
  #ifdef CONFIG_EXOFS_DEBUG
  	struct kobject *k_name, *k_tmp;
  
  	list_for_each_entry_safe(k_name, k_tmp, &exofs_kset->list, entry) {
  		printk(KERN_INFO "%s: name %s ref %d
  ",
  			__func__, kobject_name(k_name),
  			(int)atomic_read(&k_name->kref.refcount));
  	}
  #endif
  }
  /*
   * This function removes all kobjects under exofs_kset
   * At the end of it, exofs_kset kobject will have a refcount
   * of 1 which gets decremented only on exofs module unload
   */
  void exofs_sysfs_sb_del(struct exofs_sb_info *sbi)
  {
  	struct kobject *k_name, *k_tmp;
  	struct kobject *s_kobj = &sbi->s_kobj;
  
  	list_for_each_entry_safe(k_name, k_tmp, &exofs_kset->list, entry) {
  		/* Remove all that are children of this SBI */
  		if (k_name->parent == s_kobj)
  			kobject_put(k_name);
  	}
  	kobject_put(s_kobj);
  }
  
  /*
   * This function creates sysfs entries to hold the current exofs cluster
   * instance (uniquely identified by osdname,pid tuple).
   * This function gets called once per exofs mount instance.
   */
  int exofs_sysfs_sb_add(struct exofs_sb_info *sbi,
  		       struct exofs_dt_device_info *dt_dev)
  {
  	struct kobject *s_kobj;
  	int retval = 0;
  	uint64_t pid = sbi->one_comp.obj.partition;
  
  	/* allocate new uuid dirent */
  	s_kobj = &sbi->s_kobj;
  	s_kobj->kset = exofs_kset;
  	retval = kobject_init_and_add(s_kobj, &uuid_ktype,
  			&exofs_kset->kobj,  "%s_%llx", dt_dev->osdname, pid);
  	if (retval) {
  		EXOFS_ERR("ERROR: Failed to create sysfs entry for "
  			  "uuid-%s_%llx => %d
  ", dt_dev->osdname, pid, retval);
  		return -ENOMEM;
  	}
  	return 0;
  }
  
  int exofs_sysfs_odev_add(struct exofs_dev *edev, struct exofs_sb_info *sbi)
  {
  	struct kobject *d_kobj;
  	int retval = 0;
  
  	/* create osd device group which contains following attributes
  	 * osdname, systemid & uri
  	 */
  	d_kobj = &edev->ed_kobj;
  	d_kobj->kset = exofs_kset;
  	retval = kobject_init_and_add(d_kobj, &odev_ktype,
  			&sbi->s_kobj, "dev%u", edev->did);
  	if (retval) {
  		EXOFS_ERR("ERROR: Failed to create sysfs entry for "
  				"device dev%u
  ", edev->did);
  		return retval;
  	}
  	return 0;
  }
  
  int exofs_sysfs_init(void)
  {
  	exofs_kset = kset_create_and_add("exofs", NULL, fs_kobj);
  	if (!exofs_kset) {
  		EXOFS_ERR("ERROR: kset_create_and_add exofs failed
  ");
  		return -ENOMEM;
  	}
  	return 0;
  }
  
  void exofs_sysfs_uninit(void)
  {
  	kset_unregister(exofs_kset);
  }