fs/xfs/xfs_alloc.h - maze/linux - Git at Google

 /*
  * 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

 /*
  * 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 */

 /*
  * 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 */

 /*
  * 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 */

 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__ */

 #endif	/* __XFS_ALLOC_H__ */
	/*
	* 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

	/*
	* 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 */

	/*
	* 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 */

	/*
	* 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 */

	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__ */

	#endif /* __XFS_ALLOC_H__ */