/*
     md_k.h : kernel internal structure of the Linux MD driver
            Copyright (C) 1996-98 Ingo Molnar, Gadi Oxman
  	  
     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, or (at your option)
     any later version.
     
     You should have received a copy of the GNU General Public License
     (for example /usr/src/linux/COPYING); if not, write to the Free
     Software Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.  
  */
  
  #ifndef _MD_K_H
  #define _MD_K_H

  /* and dm-bio-list.h is not under include/linux because.... ??? */
  #include "../../../drivers/md/dm-bio-list.h"

  #ifdef CONFIG_BLOCK

  #define	LEVEL_MULTIPATH		(-4)
  #define	LEVEL_LINEAR		(-1)
  #define	LEVEL_FAULTY		(-5)

  /* we need a value for 'no level specified' and 0
   * means 'raid0', so we need something else.  This is
   * for internal use only
   */
  #define	LEVEL_NONE		(-1000000)

  #define MaxSector (~(sector_t)0)

  typedef struct mddev_s mddev_t;
  typedef struct mdk_rdev_s mdk_rdev_t;

  /*
   * options passed in raidrun:
   */

  /* Currently this must fit in an 'int' */

  #define MAX_CHUNK_SIZE (1<<30)

  
  /*

   * MD's 'extended' device
   */
  struct mdk_rdev_s
  {
  	struct list_head same_set;	/* RAID devices within the same set */
  
  	sector_t size;			/* Device size (in blocks) */
  	mddev_t *mddev;			/* RAID array if running */
  	unsigned long last_events;	/* IO event timestamp */
  
  	struct block_device *bdev;	/* block device handle */
  
  	struct page	*sb_page;
  	int		sb_loaded;

  	__u64		sb_events;

  	sector_t	data_offset;	/* start of data in array */
  	sector_t	sb_offset;

  	int		sb_size;	/* bytes in the superblock */

  	int		preferred_minor;	/* autorun support */

  	struct kobject	kobj;

  	/* A device can be in one of three states based on two flags:
  	 * Not working:   faulty==1 in_sync==0
  	 * Fully working: faulty==0 in_sync==1
  	 * Working, but not
  	 * in sync with array
  	 *                faulty==0 in_sync==0
  	 *
  	 * It can never have faulty==1, in_sync==1
  	 * This reduces the burden of testing multiple flags in many cases
  	 */

  	unsigned long	flags;
  #define	Faulty		1		/* device is known to have a fault */
  #define	In_sync		2		/* device is in_sync with rest of array */

  #define	WriteMostly	4		/* Avoid reading if at all possible */

  #define	BarriersNotsupp	5		/* BIO_RW_BARRIER is not supported */

  	int desc_nr;			/* descriptor index in the superblock */
  	int raid_disk;			/* role of device in array */

  	int saved_raid_disk;		/* role that device used to have in the
  					 * array and could again if we did a partial
  					 * resync from the bitmap
  					 */

  	sector_t	recovery_offset;/* If this device has been partially
  					 * recovered, this is where we were
  					 * up to.
  					 */

  
  	atomic_t	nr_pending;	/* number of pending requests.
  					 * only maintained for arrays that
  					 * support hot removal
  					 */

  	atomic_t	read_errors;	/* number of consecutive read errors that
  					 * we have tried to ignore.
  					 */

  	atomic_t	corrected_errors; /* number of corrected read errors,
  					   * for reporting to userspace and storing
  					   * in superblock.
  					   */

  };

  struct mddev_s
  {
  	void				*private;

  	struct mdk_personality		*pers;

  	dev_t				unit;
  	int				md_minor;
  	struct list_head 		disks;

  	unsigned long			flags;
  #define MD_CHANGE_DEVS	0	/* Some device status has changed */
  #define MD_CHANGE_CLEAN 1	/* transition to or from 'clean' */
  #define MD_CHANGE_PENDING 2	/* superblock update in progress */

  	int				ro;
  
  	struct gendisk			*gendisk;

  	struct kobject			kobj;

  	/* Superblock information */
  	int				major_version,
  					minor_version,
  					patch_version;
  	int				persistent;
  	int				chunk_size;
  	time_t				ctime, utime;
  	int				level, layout;

  	char				clevel[16];

  	int				raid_disks;
  	int				max_disks;
  	sector_t			size; /* used size of component devices */
  	sector_t			array_size; /* exported array size */
  	__u64				events;
  
  	char				uuid[16];

  	/* If the array is being reshaped, we need to record the
  	 * new shape and an indication of where we are up to.
  	 * This is written to the superblock.
  	 * If reshape_position is MaxSector, then no reshape is happening (yet).
  	 */
  	sector_t			reshape_position;
  	int				delta_disks, new_level, new_layout, new_chunk;

  	struct mdk_thread_s		*thread;	/* management thread */
  	struct mdk_thread_s		*sync_thread;	/* doing resync or reconstruct */

  	sector_t			curr_resync;	/* last block scheduled */

  	unsigned long			resync_mark;	/* a recent timestamp */
  	sector_t			resync_mark_cnt;/* blocks written at resync_mark */

  	sector_t			curr_mark_cnt; /* blocks scheduled now */

  
  	sector_t			resync_max_sectors; /* may be set by personality */

  
  	sector_t			resync_mismatches; /* count of sectors where
  							    * parity/replica mismatch found
  							    */

  
  	/* allow user-space to request suspension of IO to regions of the array */
  	sector_t			suspend_lo;
  	sector_t			suspend_hi;

  	/* if zero, use the system-wide default */
  	int				sync_speed_min;
  	int				sync_speed_max;

  	int				ok_start_degraded;

  	/* recovery/resync flags 
  	 * NEEDED:   we might need to start a resync/recover
  	 * RUNNING:  a thread is running, or about to be started
  	 * SYNC:     actually doing a resync, not a recovery
  	 * ERR:      and IO error was detected - abort the resync/recovery
  	 * INTR:     someone requested a (clean) early abort.
  	 * DONE:     thread is done and is waiting to be reaped

  	 * REQUEST:  user-space has requested a sync (used with SYNC)
  	 * CHECK:    user-space request for for check-only, no repair

  	 * RESHAPE:  A reshape is happening
  	 *
  	 * If neither SYNC or RESHAPE are set, then it is a recovery.

  	 */
  #define	MD_RECOVERY_RUNNING	0
  #define	MD_RECOVERY_SYNC	1
  #define	MD_RECOVERY_ERR		2
  #define	MD_RECOVERY_INTR	3
  #define	MD_RECOVERY_DONE	4
  #define	MD_RECOVERY_NEEDED	5

  #define	MD_RECOVERY_REQUESTED	6
  #define	MD_RECOVERY_CHECK	7

  #define MD_RECOVERY_RESHAPE	8

  #define	MD_RECOVERY_FROZEN	9

  	unsigned long			recovery;
  
  	int				in_sync;	/* know to not need resync */

  	struct mutex			reconfig_mutex;

  	atomic_t			active;
  
  	int				changed;	/* true if we might need to reread partition info */
  	int				degraded;	/* whether md should consider
  							 * adding a spare
  							 */

  	int				barriers_work;	/* initialised to true, cleared as soon
  							 * as a barrier request to slave
  							 * fails.  Only supported
  							 */
  	struct bio			*biolist; 	/* bios that need to be retried
  							 * because BIO_RW_BARRIER is not supported
  							 */

  
  	atomic_t			recovery_active; /* blocks scheduled, but not written */
  	wait_queue_head_t		recovery_wait;
  	sector_t			recovery_cp;

  
  	spinlock_t			write_lock;

  	wait_queue_head_t		sb_wait;	/* for waiting on superblock updates */

  	atomic_t			pending_writes;	/* number of active superblock writes */

  	unsigned int			safemode;	/* if set, update "clean" superblock
  							 * when no writes pending.
  							 */ 
  	unsigned int			safemode_delay;
  	struct timer_list		safemode_timer;
  	atomic_t			writes_pending; 
  	request_queue_t			*queue;	/* for plugging ... */

  	atomic_t                        write_behind; /* outstanding async IO */
  	unsigned int                    max_write_behind; /* 0 = sync */

  	struct bitmap                   *bitmap; /* the bitmap for the device */
  	struct file			*bitmap_file; /* the bitmap file */

  	long				bitmap_offset; /* offset from superblock of
  							* start of bitmap. May be
  							* negative, but not '0'
  							*/

  	long				default_bitmap_offset; /* this is the offset to use when
  								* hot-adding a bitmap.  It should
  								* eventually be settable by sysfs.
  								*/

  	struct list_head		all_mddevs;
  };
  
  
  static inline void rdev_dec_pending(mdk_rdev_t *rdev, mddev_t *mddev)
  {

  	int faulty = test_bit(Faulty, &rdev->flags);

  	if (atomic_dec_and_test(&rdev->nr_pending) && faulty)
  		set_bit(MD_RECOVERY_NEEDED, &mddev->recovery);
  }
  
  static inline void md_sync_acct(struct block_device *bdev, unsigned long nr_sectors)
  {
          atomic_add(nr_sectors, &bdev->bd_contains->bd_disk->sync_io);
  }

  struct mdk_personality

  {
  	char *name;

  	int level;
  	struct list_head list;

  	struct module *owner;
  	int (*make_request)(request_queue_t *q, struct bio *bio);
  	int (*run)(mddev_t *mddev);
  	int (*stop)(mddev_t *mddev);
  	void (*status)(struct seq_file *seq, mddev_t *mddev);
  	/* error_handler must set ->faulty and clear ->in_sync
  	 * if appropriate, and should abort recovery if needed 
  	 */
  	void (*error_handler)(mddev_t *mddev, mdk_rdev_t *rdev);
  	int (*hot_add_disk) (mddev_t *mddev, mdk_rdev_t *rdev);
  	int (*hot_remove_disk) (mddev_t *mddev, int number);
  	int (*spare_active) (mddev_t *mddev);

  	sector_t (*sync_request)(mddev_t *mddev, sector_t sector_nr, int *skipped, int go_faster);

  	int (*resize) (mddev_t *mddev, sector_t sectors);

  	int (*check_reshape) (mddev_t *mddev);
  	int (*start_reshape) (mddev_t *mddev);

  	int (*reconfig) (mddev_t *mddev, int layout, int chunk_size);

  	/* quiesce moves between quiescence states
  	 * 0 - fully active
  	 * 1 - no new requests allowed
  	 * others - reserved
  	 */
  	void (*quiesce) (mddev_t *mddev, int state);

  };

  struct md_sysfs_entry {
  	struct attribute attr;
  	ssize_t (*show)(mddev_t *, char *);
  	ssize_t (*store)(mddev_t *, const char *, size_t);
  };

  static inline char * mdname (mddev_t * mddev)
  {
  	return mddev->gendisk ? mddev->gendisk->disk_name : "mdX";
  }

  /*
   * iterates through some rdev ringlist. It's safe to remove the
   * current 'rdev'. Dont touch 'tmp' though.
   */
  #define ITERATE_RDEV_GENERIC(head,rdev,tmp)				\
  									\
  	for ((tmp) = (head).next;					\
  		(rdev) = (list_entry((tmp), mdk_rdev_t, same_set)),	\
  			(tmp) = (tmp)->next, (tmp)->prev != &(head)	\
  		; )
  /*
   * iterates through the 'same array disks' ringlist
   */
  #define ITERATE_RDEV(mddev,rdev,tmp)					\
  	ITERATE_RDEV_GENERIC((mddev)->disks,rdev,tmp)
  
  /*
   * Iterates through 'pending RAID disks'
   */
  #define ITERATE_RDEV_PENDING(rdev,tmp)					\
  	ITERATE_RDEV_GENERIC(pending_raid_disks,rdev,tmp)
  
  typedef struct mdk_thread_s {
  	void			(*run) (mddev_t *mddev);
  	mddev_t			*mddev;
  	wait_queue_head_t	wqueue;
  	unsigned long           flags;

  	struct task_struct	*tsk;

  	unsigned long		timeout;

  } mdk_thread_t;
  
  #define THREAD_WAKEUP  0
  
  #define __wait_event_lock_irq(wq, condition, lock, cmd) 		\
  do {									\
  	wait_queue_t __wait;						\
  	init_waitqueue_entry(&__wait, current);				\
  									\
  	add_wait_queue(&wq, &__wait);					\
  	for (;;) {							\
  		set_current_state(TASK_UNINTERRUPTIBLE);		\
  		if (condition)						\
  			break;						\
  		spin_unlock_irq(&lock);					\
  		cmd;							\
  		schedule();						\
  		spin_lock_irq(&lock);					\
  	}								\
  	current->state = TASK_RUNNING;					\
  	remove_wait_queue(&wq, &__wait);				\
  } while (0)
  
  #define wait_event_lock_irq(wq, condition, lock, cmd) 			\
  do {									\
  	if (condition)	 						\
  		break;							\
  	__wait_event_lock_irq(wq, condition, lock, cmd);		\
  } while (0)

  static inline void safe_put_page(struct page *p)
  {
  	if (p) put_page(p);
  }

  #endif /* CONFIG_BLOCK */

  #endif