/*
   *  linux/fs/nfs/blocklayout/blocklayout.h
   *
   *  Module for the NFSv4.1 pNFS block layout driver.
   *
   *  Copyright (c) 2006 The Regents of the University of Michigan.
   *  All rights reserved.
   *
   *  Andy Adamson <andros@citi.umich.edu>
   *  Fred Isaman <iisaman@umich.edu>
   *
   * permission is granted to use, copy, create derivative works and
   * redistribute this software and such derivative works for any purpose,
   * so long as the name of the university of michigan is not used in
   * any advertising or publicity pertaining to the use or distribution
   * of this software without specific, written prior authorization.  if
   * the above copyright notice or any other identification of the
   * university of michigan is included in any copy of any portion of
   * this software, then the disclaimer below must also be included.
   *
   * this software is provided as is, without representation from the
   * university of michigan as to its fitness for any purpose, and without
   * warranty by the university of michigan of any kind, either express
   * or implied, including without limitation the implied warranties of
   * merchantability and fitness for a particular purpose.  the regents
   * of the university of michigan shall not be liable for any damages,
   * including special, indirect, incidental, or consequential damages,
   * with respect to any claim arising out or in connection with the use
   * of the software, even if it has been or is hereafter advised of the
   * possibility of such damages.
   */
  #ifndef FS_NFS_NFS4BLOCKLAYOUT_H
  #define FS_NFS_NFS4BLOCKLAYOUT_H
  
  #include <linux/device-mapper.h>
  #include <linux/nfs_fs.h>
  #include <linux/sunrpc/rpc_pipe_fs.h>
  
  #include "../nfs4_fs.h"
  #include "../pnfs.h"
  #include "../netns.h"
  
  #define PAGE_CACHE_SECTORS (PAGE_CACHE_SIZE >> SECTOR_SHIFT)
  #define PAGE_CACHE_SECTOR_SHIFT (PAGE_CACHE_SHIFT - SECTOR_SHIFT)
  #define SECTOR_SIZE (1 << SECTOR_SHIFT)
  
  struct block_mount_id {
  	spinlock_t			bm_lock;    /* protects list */
  	struct list_head		bm_devlist; /* holds pnfs_block_dev */
  };
  
  struct pnfs_block_dev {
  	struct list_head		bm_node;
  	struct nfs4_deviceid		bm_mdevid;    /* associated devid */
  	struct block_device		*bm_mdev;     /* meta device itself */
  	struct net			*net;
  };
  
  enum exstate4 {
  	PNFS_BLOCK_READWRITE_DATA	= 0,
  	PNFS_BLOCK_READ_DATA		= 1,
  	PNFS_BLOCK_INVALID_DATA		= 2, /* mapped, but data is invalid */
  	PNFS_BLOCK_NONE_DATA		= 3  /* unmapped, it's a hole */
  };
  
  #define MY_MAX_TAGS (15) /* tag bitnums used must be less than this */
  
  struct my_tree {
  	sector_t		mtt_step_size;	/* Internal sector alignment */
  	struct list_head	mtt_stub; /* Should be a radix tree */
  };
  
  struct pnfs_inval_markings {
  	spinlock_t	im_lock;
  	struct my_tree	im_tree;	/* Sectors that need LAYOUTCOMMIT */
  	sector_t	im_block_size;	/* Server blocksize in sectors */
  	struct list_head im_extents;	/* Short extents for INVAL->RW conversion */
  };
  
  struct pnfs_inval_tracking {
  	struct list_head it_link;
  	int		 it_sector;
  	int		 it_tags;
  };
  
  /* sector_t fields are all in 512-byte sectors */
  struct pnfs_block_extent {
  	struct kref	be_refcnt;
  	struct list_head be_node;	/* link into lseg list */
  	struct nfs4_deviceid be_devid;  /* FIXME: could use device cache instead */
  	struct block_device *be_mdev;
  	sector_t	be_f_offset;	/* the starting offset in the file */
  	sector_t	be_length;	/* the size of the extent */
  	sector_t	be_v_offset;	/* the starting offset in the volume */
  	enum exstate4	be_state;	/* the state of this extent */
  	struct pnfs_inval_markings *be_inval; /* tracks INVAL->RW transition */
  };
  
  /* Shortened extent used by LAYOUTCOMMIT */
  struct pnfs_block_short_extent {
  	struct list_head bse_node;
  	struct nfs4_deviceid bse_devid;
  	struct block_device *bse_mdev;
  	sector_t	bse_f_offset;	/* the starting offset in the file */
  	sector_t	bse_length;	/* the size of the extent */
  };
  
  static inline void
  BL_INIT_INVAL_MARKS(struct pnfs_inval_markings *marks, sector_t blocksize)
  {
  	spin_lock_init(&marks->im_lock);
  	INIT_LIST_HEAD(&marks->im_tree.mtt_stub);
  	INIT_LIST_HEAD(&marks->im_extents);
  	marks->im_block_size = blocksize;
  	marks->im_tree.mtt_step_size = min((sector_t)PAGE_CACHE_SECTORS,
  					   blocksize);
  }
  
  enum extentclass4 {
  	RW_EXTENT       = 0, /* READWRTE and INVAL */
  	RO_EXTENT       = 1, /* READ and NONE */
  	EXTENT_LISTS    = 2,
  };
  
  static inline int bl_choose_list(enum exstate4 state)
  {
  	if (state == PNFS_BLOCK_READ_DATA || state == PNFS_BLOCK_NONE_DATA)
  		return RO_EXTENT;
  	else
  		return RW_EXTENT;
  }
  
  struct pnfs_block_layout {
  	struct pnfs_layout_hdr bl_layout;
  	struct pnfs_inval_markings bl_inval; /* tracks INVAL->RW transition */
  	spinlock_t		bl_ext_lock;   /* Protects list manipulation */
  	struct list_head	bl_extents[EXTENT_LISTS]; /* R and RW extents */
  	struct list_head	bl_commit;	/* Needs layout commit */
  	struct list_head	bl_committing;	/* Layout committing */
  	unsigned int		bl_count;	/* entries in bl_commit */
  	sector_t		bl_blocksize;  /* Server blocksize in sectors */
  };
  
  #define BLK_ID(lo) ((struct block_mount_id *)(NFS_SERVER(lo->plh_inode)->pnfs_ld_data))
  
  static inline struct pnfs_block_layout *
  BLK_LO2EXT(struct pnfs_layout_hdr *lo)
  {
  	return container_of(lo, struct pnfs_block_layout, bl_layout);
  }
  
  static inline struct pnfs_block_layout *
  BLK_LSEG2EXT(struct pnfs_layout_segment *lseg)
  {
  	return BLK_LO2EXT(lseg->pls_layout);
  }
  
  struct bl_pipe_msg {
  	struct rpc_pipe_msg msg;
  	wait_queue_head_t *bl_wq;
  };
  
  struct bl_msg_hdr {
  	u8  type;
  	u16 totallen; /* length of entire message, including hdr itself */
  };
  
  #define BL_DEVICE_UMOUNT               0x0 /* Umount--delete devices */
  #define BL_DEVICE_MOUNT                0x1 /* Mount--create devices*/
  #define BL_DEVICE_REQUEST_INIT         0x0 /* Start request */
  #define BL_DEVICE_REQUEST_PROC         0x1 /* User level process succeeds */
  #define BL_DEVICE_REQUEST_ERR          0x2 /* User level process fails */
  
  /* blocklayoutdev.c */
  ssize_t bl_pipe_downcall(struct file *, const char __user *, size_t);
  void bl_pipe_destroy_msg(struct rpc_pipe_msg *);
  void nfs4_blkdev_put(struct block_device *bdev);
  struct pnfs_block_dev *nfs4_blk_decode_device(struct nfs_server *server,
  						struct pnfs_device *dev);
  int nfs4_blk_process_layoutget(struct pnfs_layout_hdr *lo,
  				struct nfs4_layoutget_res *lgr, gfp_t gfp_flags);
  
  /* blocklayoutdm.c */
  void bl_free_block_dev(struct pnfs_block_dev *bdev);
  
  /* extents.c */
  struct pnfs_block_extent *
  bl_find_get_extent(struct pnfs_block_layout *bl, sector_t isect,
  		struct pnfs_block_extent **cow_read);
  int bl_mark_sectors_init(struct pnfs_inval_markings *marks,
  			     sector_t offset, sector_t length);
  void bl_put_extent(struct pnfs_block_extent *be);
  struct pnfs_block_extent *bl_alloc_extent(void);
  int bl_is_sector_init(struct pnfs_inval_markings *marks, sector_t isect);
  int encode_pnfs_block_layoutupdate(struct pnfs_block_layout *bl,
  				   struct xdr_stream *xdr,
  				   const struct nfs4_layoutcommit_args *arg);
  void clean_pnfs_block_layoutupdate(struct pnfs_block_layout *bl,
  				   const struct nfs4_layoutcommit_args *arg,
  				   int status);
  int bl_add_merge_extent(struct pnfs_block_layout *bl,
  			 struct pnfs_block_extent *new);
  int bl_mark_for_commit(struct pnfs_block_extent *be,
  			sector_t offset, sector_t length,
  			struct pnfs_block_short_extent *new);
  int bl_push_one_short_extent(struct pnfs_inval_markings *marks);
  struct pnfs_block_short_extent *
  bl_pop_one_short_extent(struct pnfs_inval_markings *marks);
  void bl_free_short_extents(struct pnfs_inval_markings *marks, int num_to_free);
  
  #endif /* FS_NFS_NFS4BLOCKLAYOUT_H */