/*

   * Copyright (c) 2000-2002,2005 Silicon Graphics, Inc.
   * All Rights Reserved.

   *

   * 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.
   *

   * This program is distributed in the hope that it would 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 this program; if not, write the Free Software Foundation,
   * Inc.,  51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA

   */
  #ifndef __XFS_ALLOC_H__
  #define	__XFS_ALLOC_H__
  
  struct xfs_buf;
  struct xfs_mount;
  struct xfs_perag;
  struct xfs_trans;
  
  /*
   * Freespace allocation types.  Argument to xfs_alloc_[v]extent.
   */
  typedef enum xfs_alloctype
  {
  	XFS_ALLOCTYPE_ANY_AG,		/* allocate anywhere, use rotor */
  	XFS_ALLOCTYPE_FIRST_AG,		/* ... start at ag 0 */
  	XFS_ALLOCTYPE_START_AG,		/* anywhere, start in this a.g. */
  	XFS_ALLOCTYPE_THIS_AG,		/* anywhere in this a.g. */
  	XFS_ALLOCTYPE_START_BNO,	/* near this block else anywhere */
  	XFS_ALLOCTYPE_NEAR_BNO,		/* in this a.g. and near this block */
  	XFS_ALLOCTYPE_THIS_BNO		/* at exactly this block */
  } xfs_alloctype_t;
  
  /*
   * Flags for xfs_alloc_fix_freelist.
   */
  #define	XFS_ALLOC_FLAG_TRYLOCK	0x00000001  /* use trylock for buffer locking */

  #define	XFS_ALLOC_FLAG_FREEING	0x00000002  /* indicate caller is freeing extents*/

  
  /*

   * In order to avoid ENOSPC-related deadlock caused by
   * out-of-order locking of AGF buffer (PV 947395), we place
   * constraints on the relationship among actual allocations for
   * data blocks, freelist blocks, and potential file data bmap
   * btree blocks. However, these restrictions may result in no
   * actual space allocated for a delayed extent, for example, a data
   * block in a certain AG is allocated but there is no additional
   * block for the additional bmap btree block due to a split of the
   * bmap btree of the file. The result of this may lead to an
   * infinite loop in xfssyncd when the file gets flushed to disk and
   * all delayed extents need to be actually allocated. To get around
   * this, we explicitly set aside a few blocks which will not be
   * reserved in delayed allocation. Considering the minimum number of
   * needed freelist blocks is 4 fsbs _per AG_, a potential split of file's bmap
   * btree requires 1 fsb, so we set the number of set-aside blocks
   * to 4 + 4*agcount.
   */
  #define XFS_ALLOC_SET_ASIDE(mp)  (4 + ((mp)->m_sb.sb_agcount * 4))
  
  /*

   * Argument structure for xfs_alloc routines.
   * This is turned into a structure to avoid having 20 arguments passed
   * down several levels of the stack.
   */
  typedef struct xfs_alloc_arg {
  	struct xfs_trans *tp;		/* transaction pointer */
  	struct xfs_mount *mp;		/* file system mount point */
  	struct xfs_buf	*agbp;		/* buffer for a.g. freelist header */
  	struct xfs_perag *pag;		/* per-ag struct for this agno */
  	xfs_fsblock_t	fsbno;		/* file system block number */
  	xfs_agnumber_t	agno;		/* allocation group number */
  	xfs_agblock_t	agbno;		/* allocation group-relative block # */
  	xfs_extlen_t	minlen;		/* minimum size of extent */
  	xfs_extlen_t	maxlen;		/* maximum size of extent */
  	xfs_extlen_t	mod;		/* mod value for extent size */
  	xfs_extlen_t	prod;		/* prod value for extent size */
  	xfs_extlen_t	minleft;	/* min blocks must be left after us */
  	xfs_extlen_t	total;		/* total blocks needed in xaction */
  	xfs_extlen_t	alignment;	/* align answer to multiple of this */
  	xfs_extlen_t	minalignslop;	/* slop for minlen+alignment calcs */
  	xfs_extlen_t	len;		/* output: actual size of extent */
  	xfs_alloctype_t	type;		/* allocation type XFS_ALLOCTYPE_... */
  	xfs_alloctype_t	otype;		/* original allocation type */
  	char		wasdel;		/* set if allocation was prev delayed */
  	char		wasfromfl;	/* set if allocation is from freelist */

  	char		isfl;		/* set if is freelist blocks - !acctg */

  	char		userdata;	/* set if this is user data */

  	xfs_fsblock_t	firstblock;	/* io first block allocated */

  } xfs_alloc_arg_t;
  
  /*
   * Defines for userdata
   */
  #define XFS_ALLOC_USERDATA		1	/* allocation is for user data*/
  #define XFS_ALLOC_INITIAL_USER_DATA	2	/* special case start of file */
  
  
  #ifdef __KERNEL__
  
  #if defined(XFS_ALLOC_TRACE)
  /*
   * Allocation tracing buffer size.
   */
  #define	XFS_ALLOC_TRACE_SIZE	4096
  extern ktrace_t *xfs_alloc_trace_buf;
  
  /*
   * Types for alloc tracing.
   */
  #define	XFS_ALLOC_KTRACE_ALLOC	1
  #define	XFS_ALLOC_KTRACE_FREE	2
  #define	XFS_ALLOC_KTRACE_MODAGF	3
  #define	XFS_ALLOC_KTRACE_BUSY	4
  #define	XFS_ALLOC_KTRACE_UNBUSY	5
  #define	XFS_ALLOC_KTRACE_BUSYSEARCH	6
  #endif

  void
  xfs_alloc_mark_busy(xfs_trans_t *tp,
  		xfs_agnumber_t agno,
  		xfs_agblock_t bno,
  		xfs_extlen_t len);
  
  void
  xfs_alloc_clear_busy(xfs_trans_t *tp,
  		xfs_agnumber_t ag,
  		int idx);
  
  #endif	/* __KERNEL__ */

  /*
   * Compute and fill in value of m_ag_maxlevels.
   */
  void
  xfs_alloc_compute_maxlevels(
  	struct xfs_mount	*mp);	/* file system mount structure */
  
  /*
   * Get a block from the freelist.
   * Returns with the buffer for the block gotten.
   */
  int				/* error */
  xfs_alloc_get_freelist(
  	struct xfs_trans *tp,	/* transaction pointer */
  	struct xfs_buf	*agbp,	/* buffer containing the agf structure */

  	xfs_agblock_t	*bnop,	/* block address retrieved from freelist */
  	int		btreeblk); /* destination is a AGF btree */

  
  /*
   * Log the given fields from the agf structure.
   */
  void
  xfs_alloc_log_agf(
  	struct xfs_trans *tp,	/* transaction pointer */
  	struct xfs_buf	*bp,	/* buffer for a.g. freelist header */
  	int		fields);/* mask of fields to be logged (XFS_AGF_...) */
  
  /*
   * Interface for inode allocation to force the pag data to be initialized.
   */
  int				/* error */
  xfs_alloc_pagf_init(
  	struct xfs_mount *mp,	/* file system mount structure */
  	struct xfs_trans *tp,	/* transaction pointer */
  	xfs_agnumber_t	agno,	/* allocation group number */
  	int		flags);	/* XFS_ALLOC_FLAGS_... */
  
  /*
   * Put the block on the freelist for the allocation group.
   */
  int				/* error */
  xfs_alloc_put_freelist(
  	struct xfs_trans *tp,	/* transaction pointer */
  	struct xfs_buf	*agbp,	/* buffer for a.g. freelist header */
  	struct xfs_buf	*agflbp,/* buffer for a.g. free block array */

  	xfs_agblock_t	bno,	/* block being freed */
  	int		btreeblk); /* owner was a AGF btree */

  
  /*
   * Read in the allocation group header (free/alloc section).
   */
  int					/* error  */
  xfs_alloc_read_agf(
  	struct xfs_mount *mp,		/* mount point structure */
  	struct xfs_trans *tp,		/* transaction pointer */
  	xfs_agnumber_t	agno,		/* allocation group number */
  	int		flags,		/* XFS_ALLOC_FLAG_... */
  	struct xfs_buf	**bpp);		/* buffer for the ag freelist header */
  
  /*
   * Allocate an extent (variable-size).
   */
  int				/* error */
  xfs_alloc_vextent(
  	xfs_alloc_arg_t	*args);	/* allocation argument structure */
  
  /*
   * Free an extent.
   */
  int				/* error */
  xfs_free_extent(
  	struct xfs_trans *tp,	/* transaction pointer */
  	xfs_fsblock_t	bno,	/* starting block number of extent */
  	xfs_extlen_t	len);	/* length of extent */

  #endif	/* __XFS_ALLOC_H__ */