fs/xfs/xfs_ag.h - linux - Git at Google

 /*
  * Copyright (c) 2000-2003,2005 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_AG_H__
 #define	__XFS_AG_H__

 /*
  * Allocation group header
  * This is divided into three structures, placed in sequential 512-byte
  * buffers after a copy of the superblock (also in a 512-byte buffer).
  */

 struct xfs_buf;
 struct xfs_mount;
 struct xfs_trans;

 #define	XFS_AGF_MAGIC	0x58414746	/* 'XAGF' */
 #define	XFS_AGI_MAGIC	0x58414749	/* 'XAGI' */
 #define	XFS_AGFL_MAGIC	0x5841464c	/* 'XAFL' */
 #define	XFS_AGF_VERSION	1
 #define	XFS_AGI_VERSION	1

 #define	XFS_AGF_GOOD_VERSION(v)	((v) == XFS_AGF_VERSION)
 #define	XFS_AGI_GOOD_VERSION(v)	((v) == XFS_AGI_VERSION)

 /*
  * Btree number 0 is bno, 1 is cnt.  This value gives the size of the
  * arrays below.
  */
 #define	XFS_BTNUM_AGF	((int)XFS_BTNUM_CNTi + 1)

 /*
  * The second word of agf_levels in the first a.g. overlaps the EFS
  * superblock's magic number.  Since the magic numbers valid for EFS
  * are > 64k, our value cannot be confused for an EFS superblock's.
  */

 typedef struct xfs_agf {
 	/*
 	 * Common allocation group header information
 	 */
 	__be32		agf_magicnum;	/* magic number == XFS_AGF_MAGIC */
 	__be32		agf_versionnum;	/* header version == XFS_AGF_VERSION */
 	__be32		agf_seqno;	/* sequence # starting from 0 */
 	__be32		agf_length;	/* size in blocks of a.g. */
 	/*
 	 * Freespace information
 	 */
 	__be32		agf_roots[XFS_BTNUM_AGF];	/* root blocks */
 	__be32		agf_spare0;	/* spare field */
 	__be32		agf_levels[XFS_BTNUM_AGF];	/* btree levels */
 	__be32		agf_spare1;	/* spare field */

 	__be32		agf_flfirst;	/* first freelist block's index */
 	__be32		agf_fllast;	/* last freelist block's index */
 	__be32		agf_flcount;	/* count of blocks in freelist */
 	__be32		agf_freeblks;	/* total free blocks */

 	__be32		agf_longest;	/* longest free space */
 	__be32		agf_btreeblks;	/* # of blocks held in AGF btrees */
 	uuid_t		agf_uuid;	/* uuid of filesystem */

 	/*
 	 * reserve some contiguous space for future logged fields before we add
 	 * the unlogged fields. This makes the range logging via flags and
 	 * structure offsets much simpler.
 	 */
 	__be64		agf_spare64[16];

 	/* unlogged fields, written during buffer writeback. */
 	__be64		agf_lsn;	/* last write sequence */
 	__be32		agf_crc;	/* crc of agf sector */
 	__be32		agf_spare2;

 	/* structure must be padded to 64 bit alignment */
 } xfs_agf_t;

 #define XFS_AGF_CRC_OFF		offsetof(struct xfs_agf, agf_crc)

 #define	XFS_AGF_MAGICNUM	0x00000001
 #define	XFS_AGF_VERSIONNUM	0x00000002
 #define	XFS_AGF_SEQNO		0x00000004
 #define	XFS_AGF_LENGTH		0x00000008
 #define	XFS_AGF_ROOTS		0x00000010
 #define	XFS_AGF_LEVELS		0x00000020
 #define	XFS_AGF_FLFIRST		0x00000040
 #define	XFS_AGF_FLLAST		0x00000080
 #define	XFS_AGF_FLCOUNT		0x00000100
 #define	XFS_AGF_FREEBLKS	0x00000200
 #define	XFS_AGF_LONGEST		0x00000400
 #define	XFS_AGF_BTREEBLKS	0x00000800
 #define	XFS_AGF_UUID		0x00001000
 #define	XFS_AGF_NUM_BITS	13
 #define	XFS_AGF_ALL_BITS	((1 << XFS_AGF_NUM_BITS) - 1)

 #define XFS_AGF_FLAGS \
 	{ XFS_AGF_MAGICNUM,	"MAGICNUM" }, \
 	{ XFS_AGF_VERSIONNUM,	"VERSIONNUM" }, \
 	{ XFS_AGF_SEQNO,	"SEQNO" }, \
 	{ XFS_AGF_LENGTH,	"LENGTH" }, \
 	{ XFS_AGF_ROOTS,	"ROOTS" }, \
 	{ XFS_AGF_LEVELS,	"LEVELS" }, \
 	{ XFS_AGF_FLFIRST,	"FLFIRST" }, \
 	{ XFS_AGF_FLLAST,	"FLLAST" }, \
 	{ XFS_AGF_FLCOUNT,	"FLCOUNT" }, \
 	{ XFS_AGF_FREEBLKS,	"FREEBLKS" }, \
 	{ XFS_AGF_LONGEST,	"LONGEST" }, \
 	{ XFS_AGF_BTREEBLKS,	"BTREEBLKS" }, \
 	{ XFS_AGF_UUID,		"UUID" }

 /* disk block (xfs_daddr_t) in the AG */
 #define XFS_AGF_DADDR(mp)	((xfs_daddr_t)(1 << (mp)->m_sectbb_log))
 #define	XFS_AGF_BLOCK(mp)	XFS_HDR_BLOCK(mp, XFS_AGF_DADDR(mp))
 #define	XFS_BUF_TO_AGF(bp)	((xfs_agf_t *)((bp)->b_addr))

 extern int xfs_read_agf(struct xfs_mount *mp, struct xfs_trans *tp,
 			xfs_agnumber_t agno, int flags, struct xfs_buf **bpp);

 /*
  * Size of the unlinked inode hash table in the agi.
  */
 #define	XFS_AGI_UNLINKED_BUCKETS	64

 typedef struct xfs_agi {
 	/*
 	 * Common allocation group header information
 	 */
 	__be32		agi_magicnum;	/* magic number == XFS_AGI_MAGIC */
 	__be32		agi_versionnum;	/* header version == XFS_AGI_VERSION */
 	__be32		agi_seqno;	/* sequence # starting from 0 */
 	__be32		agi_length;	/* size in blocks of a.g. */
 	/*
 	 * Inode information
 	 * Inodes are mapped by interpreting the inode number, so no
 	 * mapping data is needed here.
 	 */
 	__be32		agi_count;	/* count of allocated inodes */
 	__be32		agi_root;	/* root of inode btree */
 	__be32		agi_level;	/* levels in inode btree */
 	__be32		agi_freecount;	/* number of free inodes */

 	__be32		agi_newino;	/* new inode just allocated */
 	__be32		agi_dirino;	/* last directory inode chunk */
 	/*
 	 * Hash table of inodes which have been unlinked but are
 	 * still being referenced.
 	 */
 	__be32		agi_unlinked[XFS_AGI_UNLINKED_BUCKETS];
 	/*
 	 * This marks the end of logging region 1 and start of logging region 2.
 	 */
 	uuid_t		agi_uuid;	/* uuid of filesystem */
 	__be32		agi_crc;	/* crc of agi sector */
 	__be32		agi_pad32;
 	__be64		agi_lsn;	/* last write sequence */

 	__be32		agi_free_root; /* root of the free inode btree */
 	__be32		agi_free_level;/* levels in free inode btree */

 	/* structure must be padded to 64 bit alignment */
 } xfs_agi_t;

 #define XFS_AGI_CRC_OFF		offsetof(struct xfs_agi, agi_crc)

 #define	XFS_AGI_MAGICNUM	(1 << 0)
 #define	XFS_AGI_VERSIONNUM	(1 << 1)
 #define	XFS_AGI_SEQNO		(1 << 2)
 #define	XFS_AGI_LENGTH		(1 << 3)
 #define	XFS_AGI_COUNT		(1 << 4)
 #define	XFS_AGI_ROOT		(1 << 5)
 #define	XFS_AGI_LEVEL		(1 << 6)
 #define	XFS_AGI_FREECOUNT	(1 << 7)
 #define	XFS_AGI_NEWINO		(1 << 8)
 #define	XFS_AGI_DIRINO		(1 << 9)
 #define	XFS_AGI_UNLINKED	(1 << 10)
 #define	XFS_AGI_NUM_BITS_R1	11	/* end of the 1st agi logging region */
 #define	XFS_AGI_ALL_BITS_R1	((1 << XFS_AGI_NUM_BITS_R1) - 1)
 #define	XFS_AGI_FREE_ROOT	(1 << 11)
 #define	XFS_AGI_FREE_LEVEL	(1 << 12)
 #define	XFS_AGI_NUM_BITS_R2	13

 /* disk block (xfs_daddr_t) in the AG */
 #define XFS_AGI_DADDR(mp)	((xfs_daddr_t)(2 << (mp)->m_sectbb_log))
 #define	XFS_AGI_BLOCK(mp)	XFS_HDR_BLOCK(mp, XFS_AGI_DADDR(mp))
 #define	XFS_BUF_TO_AGI(bp)	((xfs_agi_t *)((bp)->b_addr))

 extern int xfs_read_agi(struct xfs_mount *mp, struct xfs_trans *tp,
 				xfs_agnumber_t agno, struct xfs_buf **bpp);

 /*
  * The third a.g. block contains the a.g. freelist, an array
  * of block pointers to blocks owned by the allocation btree code.
  */
 #define XFS_AGFL_DADDR(mp)	((xfs_daddr_t)(3 << (mp)->m_sectbb_log))
 #define	XFS_AGFL_BLOCK(mp)	XFS_HDR_BLOCK(mp, XFS_AGFL_DADDR(mp))
 #define	XFS_BUF_TO_AGFL(bp)	((xfs_agfl_t *)((bp)->b_addr))

 #define XFS_BUF_TO_AGFL_BNO(mp, bp) \
 	(xfs_sb_version_hascrc(&((mp)->m_sb)) ? \
 		&(XFS_BUF_TO_AGFL(bp)->agfl_bno[0]) : \
 		(__be32 *)(bp)->b_addr)

 /*
  * Size of the AGFL.  For CRC-enabled filesystes we steal a couple of
  * slots in the beginning of the block for a proper header with the
  * location information and CRC.
  */
 #define XFS_AGFL_SIZE(mp) \
 	(((mp)->m_sb.sb_sectsize - \
 	 (xfs_sb_version_hascrc(&((mp)->m_sb)) ? \
 		sizeof(struct xfs_agfl) : 0)) / \
 	  sizeof(xfs_agblock_t))

 typedef struct xfs_agfl {
 	__be32		agfl_magicnum;
 	__be32		agfl_seqno;
 	uuid_t		agfl_uuid;
 	__be64		agfl_lsn;
 	__be32		agfl_crc;
 	__be32		agfl_bno[];	/* actually XFS_AGFL_SIZE(mp) */
 } xfs_agfl_t;

 #define XFS_AGFL_CRC_OFF	offsetof(struct xfs_agfl, agfl_crc)

 /*
  * tags for inode radix tree
  */
 #define XFS_ICI_NO_TAG		(-1)	/* special flag for an untagged lookup
 					   in xfs_inode_ag_iterator */
 #define XFS_ICI_RECLAIM_TAG	0	/* inode is to be reclaimed */
 #define XFS_ICI_EOFBLOCKS_TAG	1	/* inode has blocks beyond EOF */

 #define	XFS_AG_MAXLEVELS(mp)		((mp)->m_ag_maxlevels)
 #define	XFS_MIN_FREELIST_RAW(bl,cl,mp)	\
 	(MIN(bl + 1, XFS_AG_MAXLEVELS(mp)) + MIN(cl + 1, XFS_AG_MAXLEVELS(mp)))
 #define	XFS_MIN_FREELIST(a,mp)		\
 	(XFS_MIN_FREELIST_RAW(		\
 		be32_to_cpu((a)->agf_levels[XFS_BTNUM_BNOi]), \
 		be32_to_cpu((a)->agf_levels[XFS_BTNUM_CNTi]), mp))
 #define	XFS_MIN_FREELIST_PAG(pag,mp)	\
 	(XFS_MIN_FREELIST_RAW(		\
 		(unsigned int)(pag)->pagf_levels[XFS_BTNUM_BNOi], \
 		(unsigned int)(pag)->pagf_levels[XFS_BTNUM_CNTi], mp))

 #define XFS_AGB_TO_FSB(mp,agno,agbno)	\
 	(((xfs_fsblock_t)(agno) << (mp)->m_sb.sb_agblklog) | (agbno))
 #define	XFS_FSB_TO_AGNO(mp,fsbno)	\
 	((xfs_agnumber_t)((fsbno) >> (mp)->m_sb.sb_agblklog))
 #define	XFS_FSB_TO_AGBNO(mp,fsbno)	\
 	((xfs_agblock_t)((fsbno) & xfs_mask32lo((mp)->m_sb.sb_agblklog)))
 #define	XFS_AGB_TO_DADDR(mp,agno,agbno)	\
 	((xfs_daddr_t)XFS_FSB_TO_BB(mp, \
 		(xfs_fsblock_t)(agno) * (mp)->m_sb.sb_agblocks + (agbno)))
 #define	XFS_AG_DADDR(mp,agno,d)		(XFS_AGB_TO_DADDR(mp, agno, 0) + (d))

 /*
  * For checking for bad ranges of xfs_daddr_t's, covering multiple
  * allocation groups or a single xfs_daddr_t that's a superblock copy.
  */
 #define	XFS_AG_CHECK_DADDR(mp,d,len)	\
 	((len) == 1 ? \
 	    ASSERT((d) == XFS_SB_DADDR || \
 		   xfs_daddr_to_agbno(mp, d) != XFS_SB_DADDR) : \
 	    ASSERT(xfs_daddr_to_agno(mp, d) == \
 		   xfs_daddr_to_agno(mp, (d) + (len) - 1)))

 #endif	/* __XFS_AG_H__ */
	/*
	* Copyright (c) 2000-2003,2005 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_AG_H__
	#define __XFS_AG_H__

	/*
	* Allocation group header
	* This is divided into three structures, placed in sequential 512-byte
	* buffers after a copy of the superblock (also in a 512-byte buffer).
	*/

	struct xfs_buf;
	struct xfs_mount;
	struct xfs_trans;

	#define XFS_AGF_MAGIC 0x58414746 /* 'XAGF' */
	#define XFS_AGI_MAGIC 0x58414749 /* 'XAGI' */
	#define XFS_AGFL_MAGIC 0x5841464c /* 'XAFL' */
	#define XFS_AGF_VERSION 1
	#define XFS_AGI_VERSION 1

	#define XFS_AGF_GOOD_VERSION(v) ((v) == XFS_AGF_VERSION)
	#define XFS_AGI_GOOD_VERSION(v) ((v) == XFS_AGI_VERSION)

	/*
	* Btree number 0 is bno, 1 is cnt. This value gives the size of the
	* arrays below.
	*/
	#define XFS_BTNUM_AGF ((int)XFS_BTNUM_CNTi + 1)

	/*
	* The second word of agf_levels in the first a.g. overlaps the EFS
	* superblock's magic number. Since the magic numbers valid for EFS
	* are > 64k, our value cannot be confused for an EFS superblock's.
	*/

	typedef struct xfs_agf {
	/*
	* Common allocation group header information
	*/
	__be32 agf_magicnum; /* magic number == XFS_AGF_MAGIC */
	__be32 agf_versionnum; /* header version == XFS_AGF_VERSION */
	__be32 agf_seqno; /* sequence # starting from 0 */
	__be32 agf_length; /* size in blocks of a.g. */
	/*
	* Freespace information
	*/
	__be32 agf_roots[XFS_BTNUM_AGF]; /* root blocks */
	__be32 agf_spare0; /* spare field */
	__be32 agf_levels[XFS_BTNUM_AGF]; /* btree levels */
	__be32 agf_spare1; /* spare field */

	__be32 agf_flfirst; /* first freelist block's index */
	__be32 agf_fllast; /* last freelist block's index */
	__be32 agf_flcount; /* count of blocks in freelist */
	__be32 agf_freeblks; /* total free blocks */

	__be32 agf_longest; /* longest free space */
	__be32 agf_btreeblks; /* # of blocks held in AGF btrees */
	uuid_t agf_uuid; /* uuid of filesystem */

	/*
	* reserve some contiguous space for future logged fields before we add
	* the unlogged fields. This makes the range logging via flags and
	* structure offsets much simpler.
	*/
	__be64 agf_spare64[16];

	/* unlogged fields, written during buffer writeback. */
	__be64 agf_lsn; /* last write sequence */
	__be32 agf_crc; /* crc of agf sector */
	__be32 agf_spare2;

	/* structure must be padded to 64 bit alignment */
	} xfs_agf_t;

	#define XFS_AGF_CRC_OFF offsetof(struct xfs_agf, agf_crc)

	#define XFS_AGF_MAGICNUM 0x00000001
	#define XFS_AGF_VERSIONNUM 0x00000002
	#define XFS_AGF_SEQNO 0x00000004
	#define XFS_AGF_LENGTH 0x00000008
	#define XFS_AGF_ROOTS 0x00000010
	#define XFS_AGF_LEVELS 0x00000020
	#define XFS_AGF_FLFIRST 0x00000040
	#define XFS_AGF_FLLAST 0x00000080
	#define XFS_AGF_FLCOUNT 0x00000100
	#define XFS_AGF_FREEBLKS 0x00000200
	#define XFS_AGF_LONGEST 0x00000400
	#define XFS_AGF_BTREEBLKS 0x00000800
	#define XFS_AGF_UUID 0x00001000
	#define XFS_AGF_NUM_BITS 13
	#define XFS_AGF_ALL_BITS ((1 << XFS_AGF_NUM_BITS) - 1)

	#define XFS_AGF_FLAGS \
	{ XFS_AGF_MAGICNUM, "MAGICNUM" }, \
	{ XFS_AGF_VERSIONNUM, "VERSIONNUM" }, \
	{ XFS_AGF_SEQNO, "SEQNO" }, \
	{ XFS_AGF_LENGTH, "LENGTH" }, \
	{ XFS_AGF_ROOTS, "ROOTS" }, \
	{ XFS_AGF_LEVELS, "LEVELS" }, \
	{ XFS_AGF_FLFIRST, "FLFIRST" }, \
	{ XFS_AGF_FLLAST, "FLLAST" }, \
	{ XFS_AGF_FLCOUNT, "FLCOUNT" }, \
	{ XFS_AGF_FREEBLKS, "FREEBLKS" }, \
	{ XFS_AGF_LONGEST, "LONGEST" }, \
	{ XFS_AGF_BTREEBLKS, "BTREEBLKS" }, \
	{ XFS_AGF_UUID, "UUID" }

	/* disk block (xfs_daddr_t) in the AG */
	#define XFS_AGF_DADDR(mp) ((xfs_daddr_t)(1 << (mp)->m_sectbb_log))
	#define XFS_AGF_BLOCK(mp) XFS_HDR_BLOCK(mp, XFS_AGF_DADDR(mp))
	#define XFS_BUF_TO_AGF(bp) ((xfs_agf_t *)((bp)->b_addr))

	extern int xfs_read_agf(struct xfs_mount mp, struct xfs_trans tp,
	xfs_agnumber_t agno, int flags, struct xfs_buf **bpp);

	/*
	* Size of the unlinked inode hash table in the agi.
	*/
	#define XFS_AGI_UNLINKED_BUCKETS 64

	typedef struct xfs_agi {
	/*
	* Common allocation group header information
	*/
	__be32 agi_magicnum; /* magic number == XFS_AGI_MAGIC */
	__be32 agi_versionnum; /* header version == XFS_AGI_VERSION */
	__be32 agi_seqno; /* sequence # starting from 0 */
	__be32 agi_length; /* size in blocks of a.g. */
	/*
	* Inode information
	* Inodes are mapped by interpreting the inode number, so no
	* mapping data is needed here.
	*/
	__be32 agi_count; /* count of allocated inodes */
	__be32 agi_root; /* root of inode btree */
	__be32 agi_level; /* levels in inode btree */
	__be32 agi_freecount; /* number of free inodes */

	__be32 agi_newino; /* new inode just allocated */
	__be32 agi_dirino; /* last directory inode chunk */
	/*
	* Hash table of inodes which have been unlinked but are
	* still being referenced.
	*/
	__be32 agi_unlinked[XFS_AGI_UNLINKED_BUCKETS];
	/*
	* This marks the end of logging region 1 and start of logging region 2.
	*/
	uuid_t agi_uuid; /* uuid of filesystem */
	__be32 agi_crc; /* crc of agi sector */
	__be32 agi_pad32;
	__be64 agi_lsn; /* last write sequence */

	__be32 agi_free_root; /* root of the free inode btree */
	__be32 agi_free_level;/* levels in free inode btree */

	/* structure must be padded to 64 bit alignment */
	} xfs_agi_t;

	#define XFS_AGI_CRC_OFF offsetof(struct xfs_agi, agi_crc)

	#define XFS_AGI_MAGICNUM (1 << 0)
	#define XFS_AGI_VERSIONNUM (1 << 1)
	#define XFS_AGI_SEQNO (1 << 2)
	#define XFS_AGI_LENGTH (1 << 3)
	#define XFS_AGI_COUNT (1 << 4)
	#define XFS_AGI_ROOT (1 << 5)
	#define XFS_AGI_LEVEL (1 << 6)
	#define XFS_AGI_FREECOUNT (1 << 7)
	#define XFS_AGI_NEWINO (1 << 8)
	#define XFS_AGI_DIRINO (1 << 9)
	#define XFS_AGI_UNLINKED (1 << 10)
	#define XFS_AGI_NUM_BITS_R1 11 /* end of the 1st agi logging region */
	#define XFS_AGI_ALL_BITS_R1 ((1 << XFS_AGI_NUM_BITS_R1) - 1)
	#define XFS_AGI_FREE_ROOT (1 << 11)
	#define XFS_AGI_FREE_LEVEL (1 << 12)
	#define XFS_AGI_NUM_BITS_R2 13

	/* disk block (xfs_daddr_t) in the AG */
	#define XFS_AGI_DADDR(mp) ((xfs_daddr_t)(2 << (mp)->m_sectbb_log))
	#define XFS_AGI_BLOCK(mp) XFS_HDR_BLOCK(mp, XFS_AGI_DADDR(mp))
	#define XFS_BUF_TO_AGI(bp) ((xfs_agi_t *)((bp)->b_addr))

	extern int xfs_read_agi(struct xfs_mount mp, struct xfs_trans tp,
	xfs_agnumber_t agno, struct xfs_buf **bpp);

	/*
	* The third a.g. block contains the a.g. freelist, an array
	* of block pointers to blocks owned by the allocation btree code.
	*/
	#define XFS_AGFL_DADDR(mp) ((xfs_daddr_t)(3 << (mp)->m_sectbb_log))
	#define XFS_AGFL_BLOCK(mp) XFS_HDR_BLOCK(mp, XFS_AGFL_DADDR(mp))
	#define XFS_BUF_TO_AGFL(bp) ((xfs_agfl_t *)((bp)->b_addr))

	#define XFS_BUF_TO_AGFL_BNO(mp, bp) \
	(xfs_sb_version_hascrc(&((mp)->m_sb)) ? \
	&(XFS_BUF_TO_AGFL(bp)->agfl_bno[0]) : \
	(__be32 *)(bp)->b_addr)

	/*
	* Size of the AGFL. For CRC-enabled filesystes we steal a couple of
	* slots in the beginning of the block for a proper header with the
	* location information and CRC.
	*/
	#define XFS_AGFL_SIZE(mp) \
	(((mp)->m_sb.sb_sectsize - \
	(xfs_sb_version_hascrc(&((mp)->m_sb)) ? \
	sizeof(struct xfs_agfl) : 0)) / \
	sizeof(xfs_agblock_t))

	typedef struct xfs_agfl {
	__be32 agfl_magicnum;
	__be32 agfl_seqno;
	uuid_t agfl_uuid;
	__be64 agfl_lsn;
	__be32 agfl_crc;
	__be32 agfl_bno[]; /* actually XFS_AGFL_SIZE(mp) */
	} xfs_agfl_t;

	#define XFS_AGFL_CRC_OFF offsetof(struct xfs_agfl, agfl_crc)

	/*
	* tags for inode radix tree
	*/
	#define XFS_ICI_NO_TAG (-1) /* special flag for an untagged lookup
	in xfs_inode_ag_iterator */
	#define XFS_ICI_RECLAIM_TAG 0 /* inode is to be reclaimed */
	#define XFS_ICI_EOFBLOCKS_TAG 1 /* inode has blocks beyond EOF */

	#define XFS_AG_MAXLEVELS(mp) ((mp)->m_ag_maxlevels)
	#define XFS_MIN_FREELIST_RAW(bl,cl,mp) \
	(MIN(bl + 1, XFS_AG_MAXLEVELS(mp)) + MIN(cl + 1, XFS_AG_MAXLEVELS(mp)))
	#define XFS_MIN_FREELIST(a,mp) \
	(XFS_MIN_FREELIST_RAW( \
	be32_to_cpu((a)->agf_levels[XFS_BTNUM_BNOi]), \
	be32_to_cpu((a)->agf_levels[XFS_BTNUM_CNTi]), mp))
	#define XFS_MIN_FREELIST_PAG(pag,mp) \
	(XFS_MIN_FREELIST_RAW( \
	(unsigned int)(pag)->pagf_levels[XFS_BTNUM_BNOi], \
	(unsigned int)(pag)->pagf_levels[XFS_BTNUM_CNTi], mp))

	#define XFS_AGB_TO_FSB(mp,agno,agbno) \
	(((xfs_fsblock_t)(agno) << (mp)->m_sb.sb_agblklog) \| (agbno))
	#define XFS_FSB_TO_AGNO(mp,fsbno) \
	((xfs_agnumber_t)((fsbno) >> (mp)->m_sb.sb_agblklog))
	#define XFS_FSB_TO_AGBNO(mp,fsbno) \
	((xfs_agblock_t)((fsbno) & xfs_mask32lo((mp)->m_sb.sb_agblklog)))
	#define XFS_AGB_TO_DADDR(mp,agno,agbno) \
	((xfs_daddr_t)XFS_FSB_TO_BB(mp, \
	(xfs_fsblock_t)(agno) * (mp)->m_sb.sb_agblocks + (agbno)))
	#define XFS_AG_DADDR(mp,agno,d) (XFS_AGB_TO_DADDR(mp, agno, 0) + (d))

	/*
	* For checking for bad ranges of xfs_daddr_t's, covering multiple
	* allocation groups or a single xfs_daddr_t that's a superblock copy.
	*/
	#define XFS_AG_CHECK_DADDR(mp,d,len) \
	((len) == 1 ? \
	ASSERT((d) == XFS_SB_DADDR \|\| \
	xfs_daddr_to_agbno(mp, d) != XFS_SB_DADDR) : \
	ASSERT(xfs_daddr_to_agno(mp, d) == \
	xfs_daddr_to_agno(mp, (d) + (len) - 1)))

	#endif /* __XFS_AG_H__ */