[net-next-2.6.git] / fs / xfs / 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;
struct xfs_busy_extent;

/*
 * Freespace allocation types.  Argument to xfs_alloc_[v]extent.
 */
#define XFS_ALLOCTYPE_ANY_AG	0x01	/* allocate anywhere, use rotor */
#define XFS_ALLOCTYPE_FIRST_AG	0x02	/* ... start at ag 0 */
#define XFS_ALLOCTYPE_START_AG	0x04	/* anywhere, start in this a.g. */
#define XFS_ALLOCTYPE_THIS_AG	0x08	/* anywhere in this a.g. */
#define XFS_ALLOCTYPE_START_BNO	0x10	/* near this block else anywhere */
#define XFS_ALLOCTYPE_NEAR_BNO	0x20	/* in this a.g. and near this block */
#define XFS_ALLOCTYPE_THIS_BNO	0x40	/* at exactly this block */

/* this should become an enum again when the tracing code is fixed */
typedef unsigned int xfs_alloctype_t;

#define XFS_ALLOC_TYPES \
	{ XFS_ALLOCTYPE_ANY_AG,		"ANY_AG" }, \
	{ XFS_ALLOCTYPE_FIRST_AG,	"FIRST_AG" }, \
	{ XFS_ALLOCTYPE_START_AG,	"START_AG" }, \
	{ XFS_ALLOCTYPE_THIS_AG,	"THIS_AG" }, \
	{ XFS_ALLOCTYPE_START_BNO,	"START_BNO" }, \
	{ XFS_ALLOCTYPE_NEAR_BNO,	"NEAR_BNO" }, \
	{ XFS_ALLOCTYPE_THIS_BNO,	"THIS_BNO" }

/*
 * 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 */

/*
 * Find the length of the longest extent in an AG.
 */
xfs_extlen_t
xfs_alloc_longest_free_extent(struct xfs_mount *mp,
		struct xfs_perag *pag);

#ifdef __KERNEL__

void
xfs_alloc_busy_insert(xfs_trans_t *tp,
		xfs_agnumber_t agno,
		xfs_agblock_t bno,
		xfs_extlen_t len);

void
xfs_alloc_busy_clear(struct xfs_mount *mp, struct xfs_busy_extent *busyp);

#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__ */
Commit	Line	Data
1da177e4	1	/*
7b718769 NS	2	* Copyright (c) 2000-2002,2005 Silicon Graphics, Inc.
7b718769 NS	3	* All Rights Reserved.
1da177e4	4	*
7b718769 NS	5	* This program is free software; you can redistribute it and/or
7b718769 NS	6	* modify it under the terms of the GNU General Public License as
1da177e4 LT	7	* published by the Free Software Foundation.
1da177e4 LT	8	*
7b718769 NS	9	* This program is distributed in the hope that it would be useful,
	10	* but WITHOUT ANY WARRANTY; without even the implied warranty of
	11	* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
	12	* GNU General Public License for more details.
1da177e4	13	*
7b718769 NS	14	* You should have received a copy of the GNU General Public License
	15	* along with this program; if not, write the Free Software Foundation,
	16	* Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
1da177e4 LT	17	*/
	18	#ifndef __XFS_ALLOC_H__
	19	#define __XFS_ALLOC_H__
	20
	21	struct xfs_buf;
	22	struct xfs_mount;
	23	struct xfs_perag;
	24	struct xfs_trans;
ed3b4d6c	25	struct xfs_busy_extent;
1da177e4 LT	26
	27	/*
	28	* Freespace allocation types. Argument to xfs_alloc_[v]extent.
	29	*/
807cbbdb CH	30	#define XFS_ALLOCTYPE_ANY_AG 0x01 /* allocate anywhere, use rotor */
	31	#define XFS_ALLOCTYPE_FIRST_AG 0x02 /* ... start at ag 0 */
	32	#define XFS_ALLOCTYPE_START_AG 0x04 /* anywhere, start in this a.g. */
	33	#define XFS_ALLOCTYPE_THIS_AG 0x08 /* anywhere in this a.g. */
	34	#define XFS_ALLOCTYPE_START_BNO 0x10 /* near this block else anywhere */
	35	#define XFS_ALLOCTYPE_NEAR_BNO 0x20 /* in this a.g. and near this block */
	36	#define XFS_ALLOCTYPE_THIS_BNO 0x40 /* at exactly this block */
	37
	38	/* this should become an enum again when the tracing code is fixed */
	39	typedef unsigned int xfs_alloctype_t;
1da177e4	40
0b1b213f CH	41	#define XFS_ALLOC_TYPES \
	42	{ XFS_ALLOCTYPE_ANY_AG, "ANY_AG" }, \
	43	{ XFS_ALLOCTYPE_FIRST_AG, "FIRST_AG" }, \
	44	{ XFS_ALLOCTYPE_START_AG, "START_AG" }, \
	45	{ XFS_ALLOCTYPE_THIS_AG, "THIS_AG" }, \
	46	{ XFS_ALLOCTYPE_START_BNO, "START_BNO" }, \
	47	{ XFS_ALLOCTYPE_NEAR_BNO, "NEAR_BNO" }, \
	48	{ XFS_ALLOCTYPE_THIS_BNO, "THIS_BNO" }
	49
1da177e4 LT	50	/*
	51	* Flags for xfs_alloc_fix_freelist.
	52	*/
	53	#define XFS_ALLOC_FLAG_TRYLOCK 0x00000001 /* use trylock for buffer locking */
d210a28c	54	#define XFS_ALLOC_FLAG_FREEING 0x00000002 /* indicate caller is freeing extents*/
1da177e4	55
4be536de DC	56	/*
	57	* In order to avoid ENOSPC-related deadlock caused by
	58	* out-of-order locking of AGF buffer (PV 947395), we place
	59	* constraints on the relationship among actual allocations for
	60	* data blocks, freelist blocks, and potential file data bmap
	61	* btree blocks. However, these restrictions may result in no
	62	* actual space allocated for a delayed extent, for example, a data
	63	* block in a certain AG is allocated but there is no additional
	64	* block for the additional bmap btree block due to a split of the
	65	* bmap btree of the file. The result of this may lead to an
	66	* infinite loop in xfssyncd when the file gets flushed to disk and
	67	* all delayed extents need to be actually allocated. To get around
	68	* this, we explicitly set aside a few blocks which will not be
	69	* reserved in delayed allocation. Considering the minimum number of
	70	* needed freelist blocks is 4 fsbs _per AG_, a potential split of file's bmap
	71	* btree requires 1 fsb, so we set the number of set-aside blocks
	72	* to 4 + 4*agcount.
	73	*/
	74	#define XFS_ALLOC_SET_ASIDE(mp) (4 + ((mp)->m_sb.sb_agcount * 4))
	75
1da177e4 LT	76	/*
	77	* Argument structure for xfs_alloc routines.
	78	* This is turned into a structure to avoid having 20 arguments passed
	79	* down several levels of the stack.
	80	*/
	81	typedef struct xfs_alloc_arg {
	82	struct xfs_trans tp; / transaction pointer */
	83	struct xfs_mount mp; / file system mount point */
	84	struct xfs_buf agbp; / buffer for a.g. freelist header */
	85	struct xfs_perag pag; / per-ag struct for this agno */
	86	xfs_fsblock_t fsbno; /* file system block number */
	87	xfs_agnumber_t agno; /* allocation group number */
	88	xfs_agblock_t agbno; /* allocation group-relative block # */
	89	xfs_extlen_t minlen; /* minimum size of extent */
	90	xfs_extlen_t maxlen; /* maximum size of extent */
	91	xfs_extlen_t mod; /* mod value for extent size */
	92	xfs_extlen_t prod; /* prod value for extent size */
	93	xfs_extlen_t minleft; /* min blocks must be left after us */
	94	xfs_extlen_t total; /* total blocks needed in xaction */
	95	xfs_extlen_t alignment; /* align answer to multiple of this */
	96	xfs_extlen_t minalignslop; /* slop for minlen+alignment calcs */
	97	xfs_extlen_t len; /* output: actual size of extent */
	98	xfs_alloctype_t type; /* allocation type XFS_ALLOCTYPE_... */
	99	xfs_alloctype_t otype; /* original allocation type */
	100	char wasdel; /* set if allocation was prev delayed */
	101	char wasfromfl; /* set if allocation is from freelist */
c41564b5	102	char isfl; /* set if is freelist blocks - !acctg */
1da177e4	103	char userdata; /* set if this is user data */
d210a28c	104	xfs_fsblock_t firstblock; /* io first block allocated */
1da177e4 LT	105	} xfs_alloc_arg_t;
	106
	107	/*
	108	* Defines for userdata
	109	*/
	110	#define XFS_ALLOC_USERDATA 1 /* allocation is for user data*/
	111	#define XFS_ALLOC_INITIAL_USER_DATA 2 /* special case start of file */
	112
6cc87645 DC	113	/*
	114	* Find the length of the longest extent in an AG.
	115	*/
	116	xfs_extlen_t
	117	xfs_alloc_longest_free_extent(struct xfs_mount *mp,
	118	struct xfs_perag *pag);
1da177e4 LT	119
	120	#ifdef __KERNEL__
	121
847fff5c	122	void
ed3b4d6c	123	xfs_alloc_busy_insert(xfs_trans_t *tp,
847fff5c BN	124	xfs_agnumber_t agno,
	125	xfs_agblock_t bno,
	126	xfs_extlen_t len);
	127
	128	void
ed3b4d6c	129	xfs_alloc_busy_clear(struct xfs_mount mp, struct xfs_busy_extent busyp);
847fff5c BN	130
	131	#endif /* __KERNEL__ */
	132
1da177e4 LT	133	/*
	134	* Compute and fill in value of m_ag_maxlevels.
	135	*/
	136	void
	137	xfs_alloc_compute_maxlevels(
	138	struct xfs_mount mp); / file system mount structure */
	139
	140	/*
	141	* Get a block from the freelist.
	142	* Returns with the buffer for the block gotten.
	143	*/
	144	int /* error */
	145	xfs_alloc_get_freelist(
	146	struct xfs_trans tp, / transaction pointer */
	147	struct xfs_buf agbp, / buffer containing the agf structure */
92821e2b DC	148	xfs_agblock_t bnop, / block address retrieved from freelist */
92821e2b DC	149	int btreeblk); /* destination is a AGF btree */
1da177e4 LT	150
	151	/*
	152	* Log the given fields from the agf structure.
	153	*/
	154	void
	155	xfs_alloc_log_agf(
	156	struct xfs_trans tp, / transaction pointer */
	157	struct xfs_buf bp, / buffer for a.g. freelist header */
	158	int fields);/* mask of fields to be logged (XFS_AGF_...) */
	159
	160	/*
	161	* Interface for inode allocation to force the pag data to be initialized.
	162	*/
	163	int /* error */
	164	xfs_alloc_pagf_init(
	165	struct xfs_mount mp, / file system mount structure */
	166	struct xfs_trans tp, / transaction pointer */
	167	xfs_agnumber_t agno, /* allocation group number */
	168	int flags); /* XFS_ALLOC_FLAGS_... */
	169
	170	/*
	171	* Put the block on the freelist for the allocation group.
	172	*/
	173	int /* error */
	174	xfs_alloc_put_freelist(
	175	struct xfs_trans tp, / transaction pointer */
	176	struct xfs_buf agbp, / buffer for a.g. freelist header */
	177	struct xfs_buf agflbp,/ buffer for a.g. free block array */
92821e2b DC	178	xfs_agblock_t bno, /* block being freed */
92821e2b DC	179	int btreeblk); /* owner was a AGF btree */
1da177e4 LT	180
	181	/*
	182	* Read in the allocation group header (free/alloc section).
	183	*/
	184	int /* error */
	185	xfs_alloc_read_agf(
	186	struct xfs_mount mp, / mount point structure */
	187	struct xfs_trans tp, / transaction pointer */
	188	xfs_agnumber_t agno, /* allocation group number */
	189	int flags, /* XFS_ALLOC_FLAG_... */
	190	struct xfs_buf *bpp); / buffer for the ag freelist header */
	191
	192	/*
	193	* Allocate an extent (variable-size).
	194	*/
	195	int /* error */
	196	xfs_alloc_vextent(
	197	xfs_alloc_arg_t args); / allocation argument structure */
	198
	199	/*
	200	* Free an extent.
	201	*/
	202	int /* error */
	203	xfs_free_extent(
	204	struct xfs_trans tp, / transaction pointer */
	205	xfs_fsblock_t bno, /* starting block number of extent */
	206	xfs_extlen_t len); /* length of extent */
	207
1da177e4	208	#endif /* __XFS_ALLOC_H__ */