text: /*
   * 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_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 */
  } xfs_agf_t;
  
  #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_NUM_BITS	12
  #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" }
  
  /* 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];
  } xfs_agi_t;
  
  #define	XFS_AGI_MAGICNUM	0x00000001
  #define	XFS_AGI_VERSIONNUM	0x00000002
  #define	XFS_AGI_SEQNO		0x00000004
  #define	XFS_AGI_LENGTH		0x00000008
  #define	XFS_AGI_COUNT		0x00000010
  #define	XFS_AGI_ROOT		0x00000020
  #define	XFS_AGI_LEVEL		0x00000040
  #define	XFS_AGI_FREECOUNT	0x00000080
  #define	XFS_AGI_NEWINO		0x00000100
  #define	XFS_AGI_DIRINO		0x00000200
  #define	XFS_AGI_UNLINKED	0x00000400
  #define	XFS_AGI_NUM_BITS	11
  #define	XFS_AGI_ALL_BITS	((1 << XFS_AGI_NUM_BITS) - 1)
  
  /* 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_AGFL_SIZE(mp)	((mp)->m_sb.sb_sectsize / sizeof(xfs_agblock_t))
  #define	XFS_BUF_TO_AGFL(bp)	((xfs_agfl_t *)((bp)->b_addr))
  
  typedef struct xfs_agfl {
  	__be32		agfl_bno[1];	/* actually XFS_AGFL_SIZE(mp) */
  } xfs_agfl_t;
  
  /*
   * Per-ag incore structure, copies of information in agf and agi,
   * to improve the performance of allocation group selection.
   */
  #define XFS_PAGB_NUM_SLOTS	128
  
  typedef struct xfs_perag {
  	struct xfs_mount *pag_mount;	/* owner filesystem */
  	xfs_agnumber_t	pag_agno;	/* AG this structure belongs to */
  	atomic_t	pag_ref;	/* perag reference count */
  	char		pagf_init;	/* this agf's entry is initialized */
  	char		pagi_init;	/* this agi's entry is initialized */
  	char		pagf_metadata;	/* the agf is preferred to be metadata */
  	char		pagi_inodeok;	/* The agi is ok for inodes */
  	__uint8_t	pagf_levels[XFS_BTNUM_AGF];
  					/* # of levels in bno & cnt btree */
  	__uint32_t	pagf_flcount;	/* count of blocks in freelist */
  	xfs_extlen_t	pagf_freeblks;	/* total free blocks */
  	xfs_extlen_t	pagf_longest;	/* longest free space */
  	__uint32_t	pagf_btreeblks;	/* # of blocks held in AGF btrees */
  	xfs_agino_t	pagi_freecount;	/* number of free inodes */
  	xfs_agino_t	pagi_count;	/* number of allocated inodes */
  
  	/*
  	 * Inode allocation search lookup optimisation.
  	 * If the pagino matches, the search for new inodes
  	 * doesn't need to search the near ones again straight away
  	 */
  	xfs_agino_t	pagl_pagino;
  	xfs_agino_t	pagl_leftrec;
  	xfs_agino_t	pagl_rightrec;
  #ifdef __KERNEL__
  	spinlock_t	pagb_lock;	/* lock for pagb_tree */
  	struct rb_root	pagb_tree;	/* ordered tree of busy extents */
  
  	atomic_t        pagf_fstrms;    /* # of filestreams active in this AG */
  
  	spinlock_t	pag_ici_lock;	/* incore inode cache lock */
  	struct radix_tree_root pag_ici_root;	/* incore inode cache root */
  	int		pag_ici_reclaimable;	/* reclaimable inodes */
  	struct mutex	pag_ici_reclaim_lock;	/* serialisation point */
  	unsigned long	pag_ici_reclaim_cursor;	/* reclaim restart point */
  
  	/* buffer cache index */
  	spinlock_t	pag_buf_lock;	/* lock for pag_buf_tree */
  	struct rb_root	pag_buf_tree;	/* ordered tree of active buffers */
  
  	/* for rcu-safe freeing */
  	struct rcu_head	rcu_head;
  #endif
  	int		pagb_count;	/* pagb slots in use */
  } xfs_perag_t;
  
  /*
   * 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_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__ */
  