/*
   * Copyright (C) 2011
   * Boaz Harrosh <bharrosh@panasas.com>
   *
   * Public Declarations of the ORE API
   *
   * This file is part of the ORE (Object Raid Engine) library.
   *
   * ORE is free software; you can redistribute it and/or modify
   * it under the terms of the GNU General Public License version 2 as published
   * by the Free Software Foundation. (GPL v2)
   *
   * ORE 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 the ORE; if not, write to the Free Software
   * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
   */
  #ifndef __ORE_H__
  #define __ORE_H__
  
  #include <scsi/osd_initiator.h>
  #include <scsi/osd_attributes.h>
  #include <scsi/osd_sec.h>
  #include <linux/pnfs_osd_xdr.h>
  
  struct ore_comp {
  	struct osd_obj_id	obj;
  	u8			cred[OSD_CAP_LEN];
  };
  
  struct ore_layout {
  	/* Our way of looking at the data_map */

  	enum pnfs_osd_raid_algorithm4
  		 raid_algorithm;

  	unsigned stripe_unit;
  	unsigned mirrors_p1;
  
  	unsigned group_width;

  	unsigned parity;

  	u64	 group_depth;
  	unsigned group_count;

  
  	/* Cached often needed calculations filled in by
  	 * ore_verify_layout
  	 */
  	unsigned long max_io_length;	/* Max length that should be passed to
  					 * ore_get_rw_state
  					 */

  };

  struct ore_dev {
  	struct osd_dev *od;
  };

  struct ore_components {

  	unsigned	first_dev;		/* First logical device no    */

  	unsigned	numdevs;		/* Num of devices in array    */
  	/* If @single_comp == EC_SINGLE_COMP, @comps points to a single
  	 * component. else there are @numdevs components
  	 */
  	enum EC_COMP_USAGE {
  		EC_SINGLE_COMP = 0, EC_MULTPLE_COMPS = 0xffffffff
  	}		single_comp;
  	struct ore_comp	*comps;

  
  	/* Array of pointers to ore_dev-* . User will usually have these pointed
  	 * too a bigger struct which contain an "ore_dev ored" member and use
  	 * container_of(oc->ods[i], struct foo_dev, ored) to access the bigger
  	 * structure.
  	 */
  	struct ore_dev	**ods;

  };

  /* ore_comp_dev Recievies a logical device index */
  static inline struct osd_dev *ore_comp_dev(
  	const struct ore_components *oc, unsigned i)
  {

  	BUG_ON((i < oc->first_dev) || (oc->first_dev + oc->numdevs <= i));
  	return oc->ods[i - oc->first_dev]->od;

  }
  
  static inline void ore_comp_set_dev(
  	struct ore_components *oc, unsigned i, struct osd_dev *od)
  {

  	oc->ods[i - oc->first_dev]->od = od;

  }

  struct ore_striping_info {

  	u64 offset;

  	u64 obj_offset;

  	u64 length;
  	u64 first_stripe_start; /* only used in raid writes */

  	u64 M; /* for truncate */

  	unsigned bytes_in_stripe;

  	unsigned dev;

  	unsigned par_dev;

  	unsigned unit_off;

  	unsigned cur_pg;

  	unsigned cur_comp;

  };

  struct ore_io_state;
  typedef void (*ore_io_done_fn)(struct ore_io_state *ios, void *private);

  struct _ore_r4w_op {
  	/* @Priv given here is passed ios->private */
  	struct page * (*get_page)(void *priv, u64 page_index, bool *uptodate);
  	void (*put_page)(void *priv, struct page *page);
  };

  
  struct ore_io_state {
  	struct kref		kref;

  	struct ore_striping_info si;

  
  	void			*private;
  	ore_io_done_fn	done;
  
  	struct ore_layout	*layout;

  	struct ore_components	*oc;

  
  	/* Global read/write IO*/
  	loff_t			offset;
  	unsigned long		length;
  	void			*kern_buff;
  
  	struct page		**pages;
  	unsigned		nr_pages;
  	unsigned		pgbase;
  	unsigned		pages_consumed;
  
  	/* Attributes */
  	unsigned		in_attr_len;
  	struct osd_attr		*in_attr;
  	unsigned		out_attr_len;
  	struct osd_attr		*out_attr;
  
  	bool			reading;

  	/* House keeping of Parity pages */
  	bool			extra_part_alloc;
  	struct page		**parity_pages;
  	unsigned		max_par_pages;
  	unsigned		cur_par_page;
  	unsigned		sgs_per_dev;

  	struct __stripe_pages_2d *sp2d;
  	struct ore_io_state	 *ios_read_4_write;
  	const struct _ore_r4w_op *r4w;

  	/* Variable array of size numdevs */
  	unsigned numdevs;
  	struct ore_per_dev_state {
  		struct osd_request *or;
  		struct bio *bio;
  		loff_t offset;
  		unsigned length;

  		unsigned last_sgs_total;

  		unsigned dev;

  		struct osd_sg_entry *sglist;
  		unsigned cur_sg;

  	} per_dev[];
  };
  
  static inline unsigned ore_io_state_size(unsigned numdevs)
  {
  	return sizeof(struct ore_io_state) +
  		sizeof(struct ore_per_dev_state) * numdevs;
  }
  
  /* ore.c */

  int ore_verify_layout(unsigned total_comps, struct ore_layout *layout);

  void ore_calc_stripe_info(struct ore_layout *layout, u64 file_offset,

  			  u64 length, struct ore_striping_info *si);

  int ore_get_rw_state(struct ore_layout *layout, struct ore_components *comps,
  		     bool is_reading, u64 offset, u64 length,
  		     struct ore_io_state **ios);
  int ore_get_io_state(struct ore_layout *layout, struct ore_components *comps,
  		     struct ore_io_state **ios);
  void ore_put_io_state(struct ore_io_state *ios);

  typedef void (*ore_on_dev_error)(struct ore_io_state *ios, struct ore_dev *od,
  	unsigned dev_index, enum osd_err_priority oep,
  	u64 dev_offset, u64  dev_len);
  int ore_check_io(struct ore_io_state *ios, ore_on_dev_error rep);

  
  int ore_create(struct ore_io_state *ios);
  int ore_remove(struct ore_io_state *ios);
  int ore_write(struct ore_io_state *ios);
  int ore_read(struct ore_io_state *ios);
  int ore_truncate(struct ore_layout *layout, struct ore_components *comps,
  		 u64 size);
  
  int extract_attr_from_ios(struct ore_io_state *ios, struct osd_attr *attr);
  
  extern const struct osd_attr g_attr_logical_length;
  
  #endif