[deliverable/linux.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_btree_cur;
struct xfs_mount;
struct xfs_perag;
struct xfs_trans;

extern struct workqueue_struct *xfs_alloc_wq;

/*
 * 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))

/*
 * When deciding how much space to allocate out of an AG, we limit the
 * allocation maximum size to the size the AG. However, we cannot use all the
 * blocks in the AG - some are permanently used by metadata. These
 * blocks are generally:
 *	- the AG superblock, AGF, AGI and AGFL
 *	- the AGF (bno and cnt) and AGI btree root blocks
 *	- 4 blocks on the AGFL according to XFS_ALLOC_SET_ASIDE() limits
 *
 * The AG headers are sector sized, so the amount of space they take up is
 * dependent on filesystem geometry. The others are all single blocks.
 */
#define XFS_ALLOC_AG_MAX_USABLE(mp)	\
	((mp)->m_sb.sb_agblocks - XFS_BB_TO_FSB(mp, XFS_FSS_TO_BB(mp, 4)) - 7)


/*
 * 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 */
	struct completion *done;
	struct work_struct work;
	int		result;
} 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);

/*
 * 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 */

int					/* error */
xfs_alloc_lookup_le(
	struct xfs_btree_cur	*cur,	/* btree cursor */
	xfs_agblock_t		bno,	/* starting block of extent */
	xfs_extlen_t		len,	/* length of extent */
	int			*stat);	/* success/failure */

int				/* error */
xfs_alloc_lookup_ge(
	struct xfs_btree_cur	*cur,	/* btree cursor */
	xfs_agblock_t		bno,	/* starting block of extent */
	xfs_extlen_t		len,	/* length of extent */
	int			*stat);	/* success/failure */

int					/* error */
xfs_alloc_get_rec(
	struct xfs_btree_cur	*cur,	/* btree cursor */
	xfs_agblock_t		*bno,	/* output: starting block of extent */
	xfs_extlen_t		*len,	/* output: length of extent */
	int			*stat);	/* output: success/failure */

#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;
a46db608	22	struct xfs_btree_cur;
1da177e4 LT	23	struct xfs_mount;
	24	struct xfs_perag;
	25	struct xfs_trans;
	26
c999a223 DC	27	extern struct workqueue_struct *xfs_alloc_wq;
c999a223 DC	28
1da177e4 LT	29	/*
	30	* Freespace allocation types. Argument to xfs_alloc_[v]extent.
	31	*/
807cbbdb CH	32	#define XFS_ALLOCTYPE_ANY_AG 0x01 /* allocate anywhere, use rotor */
	33	#define XFS_ALLOCTYPE_FIRST_AG 0x02 /* ... start at ag 0 */
	34	#define XFS_ALLOCTYPE_START_AG 0x04 /* anywhere, start in this a.g. */
	35	#define XFS_ALLOCTYPE_THIS_AG 0x08 /* anywhere in this a.g. */
	36	#define XFS_ALLOCTYPE_START_BNO 0x10 /* near this block else anywhere */
	37	#define XFS_ALLOCTYPE_NEAR_BNO 0x20 /* in this a.g. and near this block */
	38	#define XFS_ALLOCTYPE_THIS_BNO 0x40 /* at exactly this block */
	39
	40	/* this should become an enum again when the tracing code is fixed */
	41	typedef unsigned int xfs_alloctype_t;
1da177e4	42
0b1b213f CH	43	#define XFS_ALLOC_TYPES \
	44	{ XFS_ALLOCTYPE_ANY_AG, "ANY_AG" }, \
	45	{ XFS_ALLOCTYPE_FIRST_AG, "FIRST_AG" }, \
	46	{ XFS_ALLOCTYPE_START_AG, "START_AG" }, \
	47	{ XFS_ALLOCTYPE_THIS_AG, "THIS_AG" }, \
	48	{ XFS_ALLOCTYPE_START_BNO, "START_BNO" }, \
	49	{ XFS_ALLOCTYPE_NEAR_BNO, "NEAR_BNO" }, \
	50	{ XFS_ALLOCTYPE_THIS_BNO, "THIS_BNO" }
	51
1da177e4 LT	52	/*
	53	* Flags for xfs_alloc_fix_freelist.
	54	*/
	55	#define XFS_ALLOC_FLAG_TRYLOCK 0x00000001 /* use trylock for buffer locking */
d210a28c	56	#define XFS_ALLOC_FLAG_FREEING 0x00000002 /* indicate caller is freeing extents*/
1da177e4	57
4be536de DC	58	/*
	59	* In order to avoid ENOSPC-related deadlock caused by
	60	* out-of-order locking of AGF buffer (PV 947395), we place
	61	* constraints on the relationship among actual allocations for
	62	* data blocks, freelist blocks, and potential file data bmap
	63	* btree blocks. However, these restrictions may result in no
	64	* actual space allocated for a delayed extent, for example, a data
	65	* block in a certain AG is allocated but there is no additional
	66	* block for the additional bmap btree block due to a split of the
	67	* bmap btree of the file. The result of this may lead to an
	68	* infinite loop in xfssyncd when the file gets flushed to disk and
	69	* all delayed extents need to be actually allocated. To get around
	70	* this, we explicitly set aside a few blocks which will not be
	71	* reserved in delayed allocation. Considering the minimum number of
	72	* needed freelist blocks is 4 fsbs _per AG_, a potential split of file's bmap
	73	* btree requires 1 fsb, so we set the number of set-aside blocks
	74	* to 4 + 4*agcount.
	75	*/
	76	#define XFS_ALLOC_SET_ASIDE(mp) (4 + ((mp)->m_sb.sb_agcount * 4))
	77
14b064ce DC	78	/*
	79	* When deciding how much space to allocate out of an AG, we limit the
	80	* allocation maximum size to the size the AG. However, we cannot use all the
	81	* blocks in the AG - some are permanently used by metadata. These
	82	* blocks are generally:
	83	* - the AG superblock, AGF, AGI and AGFL
	84	* - the AGF (bno and cnt) and AGI btree root blocks
	85	* - 4 blocks on the AGFL according to XFS_ALLOC_SET_ASIDE() limits
	86	*
	87	* The AG headers are sector sized, so the amount of space they take up is
	88	* dependent on filesystem geometry. The others are all single blocks.
	89	*/
	90	#define XFS_ALLOC_AG_MAX_USABLE(mp) \
	91	((mp)->m_sb.sb_agblocks - XFS_BB_TO_FSB(mp, XFS_FSS_TO_BB(mp, 4)) - 7)
	92
	93
1da177e4 LT	94	/*
	95	* Argument structure for xfs_alloc routines.
	96	* This is turned into a structure to avoid having 20 arguments passed
	97	* down several levels of the stack.
	98	*/
	99	typedef struct xfs_alloc_arg {
	100	struct xfs_trans tp; / transaction pointer */
	101	struct xfs_mount mp; / file system mount point */
	102	struct xfs_buf agbp; / buffer for a.g. freelist header */
	103	struct xfs_perag pag; / per-ag struct for this agno */
	104	xfs_fsblock_t fsbno; /* file system block number */
	105	xfs_agnumber_t agno; /* allocation group number */
	106	xfs_agblock_t agbno; /* allocation group-relative block # */
	107	xfs_extlen_t minlen; /* minimum size of extent */
	108	xfs_extlen_t maxlen; /* maximum size of extent */
	109	xfs_extlen_t mod; /* mod value for extent size */
	110	xfs_extlen_t prod; /* prod value for extent size */
	111	xfs_extlen_t minleft; /* min blocks must be left after us */
	112	xfs_extlen_t total; /* total blocks needed in xaction */
	113	xfs_extlen_t alignment; /* align answer to multiple of this */
	114	xfs_extlen_t minalignslop; /* slop for minlen+alignment calcs */
	115	xfs_extlen_t len; /* output: actual size of extent */
	116	xfs_alloctype_t type; /* allocation type XFS_ALLOCTYPE_... */
	117	xfs_alloctype_t otype; /* original allocation type */
	118	char wasdel; /* set if allocation was prev delayed */
	119	char wasfromfl; /* set if allocation is from freelist */
c41564b5	120	char isfl; /* set if is freelist blocks - !acctg */
1da177e4	121	char userdata; /* set if this is user data */
d210a28c	122	xfs_fsblock_t firstblock; /* io first block allocated */
c999a223 DC	123	struct completion *done;
	124	struct work_struct work;
	125	int result;
1da177e4 LT	126	} xfs_alloc_arg_t;
	127
	128	/*
	129	* Defines for userdata
	130	*/
	131	#define XFS_ALLOC_USERDATA 1 /* allocation is for user data*/
	132	#define XFS_ALLOC_INITIAL_USER_DATA 2 /* special case start of file */
	133
6cc87645 DC	134	/*
	135	* Find the length of the longest extent in an AG.
	136	*/
	137	xfs_extlen_t
	138	xfs_alloc_longest_free_extent(struct xfs_mount *mp,
	139	struct xfs_perag *pag);
1da177e4	140
1da177e4 LT	141	/*
	142	* Compute and fill in value of m_ag_maxlevels.
	143	*/
	144	void
	145	xfs_alloc_compute_maxlevels(
	146	struct xfs_mount mp); / file system mount structure */
	147
	148	/*
	149	* Get a block from the freelist.
	150	* Returns with the buffer for the block gotten.
	151	*/
	152	int /* error */
	153	xfs_alloc_get_freelist(
	154	struct xfs_trans tp, / transaction pointer */
	155	struct xfs_buf agbp, / buffer containing the agf structure */
92821e2b DC	156	xfs_agblock_t bnop, / block address retrieved from freelist */
92821e2b DC	157	int btreeblk); /* destination is a AGF btree */
1da177e4 LT	158
	159	/*
	160	* Log the given fields from the agf structure.
	161	*/
	162	void
	163	xfs_alloc_log_agf(
	164	struct xfs_trans tp, / transaction pointer */
	165	struct xfs_buf bp, / buffer for a.g. freelist header */
	166	int fields);/* mask of fields to be logged (XFS_AGF_...) */
	167
	168	/*
	169	* Interface for inode allocation to force the pag data to be initialized.
	170	*/
	171	int /* error */
	172	xfs_alloc_pagf_init(
	173	struct xfs_mount mp, / file system mount structure */
	174	struct xfs_trans tp, / transaction pointer */
	175	xfs_agnumber_t agno, /* allocation group number */
	176	int flags); /* XFS_ALLOC_FLAGS_... */
	177
	178	/*
	179	* Put the block on the freelist for the allocation group.
	180	*/
	181	int /* error */
	182	xfs_alloc_put_freelist(
	183	struct xfs_trans tp, / transaction pointer */
	184	struct xfs_buf agbp, / buffer for a.g. freelist header */
	185	struct xfs_buf agflbp,/ buffer for a.g. free block array */
92821e2b DC	186	xfs_agblock_t bno, /* block being freed */
92821e2b DC	187	int btreeblk); /* owner was a AGF btree */
1da177e4 LT	188
	189	/*
	190	* Read in the allocation group header (free/alloc section).
	191	*/
	192	int /* error */
	193	xfs_alloc_read_agf(
	194	struct xfs_mount mp, / mount point structure */
	195	struct xfs_trans tp, / transaction pointer */
	196	xfs_agnumber_t agno, /* allocation group number */
	197	int flags, /* XFS_ALLOC_FLAG_... */
	198	struct xfs_buf *bpp); / buffer for the ag freelist header */
	199
	200	/*
	201	* Allocate an extent (variable-size).
	202	*/
	203	int /* error */
	204	xfs_alloc_vextent(
	205	xfs_alloc_arg_t args); / allocation argument structure */
	206
	207	/*
	208	* Free an extent.
	209	*/
	210	int /* error */
	211	xfs_free_extent(
	212	struct xfs_trans tp, / transaction pointer */
	213	xfs_fsblock_t bno, /* starting block number of extent */
	214	xfs_extlen_t len); /* length of extent */
	215
a46db608 CH	216	int /* error */
	217	xfs_alloc_lookup_le(
	218	struct xfs_btree_cur cur, / btree cursor */
	219	xfs_agblock_t bno, /* starting block of extent */
	220	xfs_extlen_t len, /* length of extent */
	221	int stat); / success/failure */
	222
a66d6363 DC	223	int /* error */
	224	xfs_alloc_lookup_ge(
	225	struct xfs_btree_cur cur, / btree cursor */
	226	xfs_agblock_t bno, /* starting block of extent */
	227	xfs_extlen_t len, /* length of extent */
	228	int stat); / success/failure */
	229
a46db608 CH	230	int /* error */
	231	xfs_alloc_get_rec(
	232	struct xfs_btree_cur cur, / btree cursor */
	233	xfs_agblock_t bno, / output: starting block of extent */
	234	xfs_extlen_t len, / output: length of extent */
	235	int stat); / output: success/failure */
	236
1da177e4	237	#endif /* __XFS_ALLOC_H__ */