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      1 /*
      2  * Taken from Linux kernel tree (linux/fs/xfs)
      3  *
      4  * Copyright (c) 2000-2003,2005 Silicon Graphics, Inc.
      5  * All Rights Reserved.
      6  *
      7  * Copyright (c) 2012 Paulo Alcantara <pcacjr (at) zytor.com>
      8  *
      9  * This program is free software; you can redistribute it and/or
     10  * modify it under the terms of the GNU General Public License as
     11  * published by the Free Software Foundation.
     12  *
     13  * This program is distributed in the hope that it would be useful,
     14  * but WITHOUT ANY WARRANTY; without even the implied warranty of
     15  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
     16  * GNU General Public License for more details.
     17  *
     18  * You should have received a copy of the GNU General Public License
     19  * along with this program; if not, write the Free Software Foundation,
     20  * Inc.,  51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
     21  */
     22 
     23 #ifndef XFS_AG_H_
     24 #define	XFS_AG_H_
     25 
     26 #include "xfs_types.h"
     27 
     28 /*
     29  * Allocation group header
     30  * This is divided into three structures, placed in sequential 512-byte
     31  * buffers after a copy of the superblock (also in a 512-byte buffer).
     32  */
     33 
     34 typedef uint32_t xfs_agino_t;
     35 
     36 struct xfs_buf;
     37 struct xfs_mount;
     38 struct xfs_trans;
     39 
     40 #define	XFS_AGF_MAGIC	"XAGF"
     41 #define	XFS_AGF_VERSION	1
     42 #define	XFS_AGI_VERSION	1
     43 
     44 #define	XFS_AGF_GOOD_VERSION(v)	((v) == XFS_AGF_VERSION)
     45 #define	XFS_AGI_GOOD_VERSION(v)	((v) == XFS_AGI_VERSION)
     46 
     47 /*
     48  * Btree number 0 is bno, 1 is cnt.  This value gives the size of the
     49  * arrays below.
     50  */
     51 #define	XFS_BTNUM_AGF	((int)XFS_BTNUM_CNTi + 1)
     52 
     53 /*
     54  * The second word of agf_levels in the first a.g. overlaps the EFS
     55  * superblock's magic number.  Since the magic numbers valid for EFS
     56  * are > 64k, our value cannot be confused for an EFS superblock's.
     57  */
     58 
     59 typedef struct xfs_agf {
     60 	/*
     61 	 * Common allocation group header information
     62 	 */
     63 	uint32_t		agf_magicnum;	/* magic number == XFS_AGF_MAGIC */
     64 	uint32_t		agf_versionnum;	/* header version == XFS_AGF_VERSION */
     65 	uint32_t		agf_seqno;	/* sequence # starting from 0 */
     66 	uint32_t		agf_length;	/* size in blocks of a.g. */
     67 	/*
     68 	 * Freespace information
     69 	 */
     70 	uint32_t		agf_roots[XFS_BTNUM_AGF];	/* root blocks */
     71 	uint32_t		agf_spare0;	/* spare field */
     72 	uint32_t		agf_levels[XFS_BTNUM_AGF];	/* btree levels */
     73 	uint32_t		agf_spare1;	/* spare field */
     74 	uint32_t		agf_flfirst;	/* first freelist block's index */
     75 	uint32_t		agf_fllast;	/* last freelist block's index */
     76 	uint32_t		agf_flcount;	/* count of blocks in freelist */
     77 	uint32_t		agf_freeblks;	/* total free blocks */
     78 	uint32_t		agf_longest;	/* longest free space */
     79 	uint32_t		agf_btreeblks;	/* # of blocks held in AGF btrees */
     80 } xfs_agf_t;
     81 
     82 #define	XFS_AGF_MAGICNUM	0x00000001
     83 #define	XFS_AGF_VERSIONNUM	0x00000002
     84 #define	XFS_AGF_SEQNO		0x00000004
     85 #define	XFS_AGF_LENGTH		0x00000008
     86 #define	XFS_AGF_ROOTS		0x00000010
     87 #define	XFS_AGF_LEVELS		0x00000020
     88 #define	XFS_AGF_FLFIRST		0x00000040
     89 #define	XFS_AGF_FLLAST		0x00000080
     90 #define	XFS_AGF_FLCOUNT		0x00000100
     91 #define	XFS_AGF_FREEBLKS	0x00000200
     92 #define	XFS_AGF_LONGEST		0x00000400
     93 #define	XFS_AGF_BTREEBLKS	0x00000800
     94 #define	XFS_AGF_NUM_BITS	12
     95 #define	XFS_AGF_ALL_BITS	((1 << XFS_AGF_NUM_BITS) - 1)
     96 
     97 #define XFS_AGF_FLAGS \
     98 	{ XFS_AGF_MAGICNUM,	"MAGICNUM" }, \
     99 	{ XFS_AGF_VERSIONNUM,	"VERSIONNUM" }, \
    100 	{ XFS_AGF_SEQNO,	"SEQNO" }, \
    101 	{ XFS_AGF_LENGTH,	"LENGTH" }, \
    102 	{ XFS_AGF_ROOTS,	"ROOTS" }, \
    103 	{ XFS_AGF_LEVELS,	"LEVELS" }, \
    104 	{ XFS_AGF_FLFIRST,	"FLFIRST" }, \
    105 	{ XFS_AGF_FLLAST,	"FLLAST" }, \
    106 	{ XFS_AGF_FLCOUNT,	"FLCOUNT" }, \
    107 	{ XFS_AGF_FREEBLKS,	"FREEBLKS" }, \
    108 	{ XFS_AGF_LONGEST,	"LONGEST" }, \
    109 	{ XFS_AGF_BTREEBLKS,	"BTREEBLKS" }
    110 
    111 /* disk block (xfs_daddr_t) in the AG */
    112 #define XFS_AGF_DADDR(mp)	((xfs_daddr_t)(1 << (mp)->m_sectbb_log))
    113 #define	XFS_AGF_BLOCK(mp)	XFS_HDR_BLOCK(mp, XFS_AGF_DADDR(mp))
    114 #define	XFS_BUF_TO_AGF(bp)	((xfs_agf_t *)((bp)->b_addr))
    115 
    116 extern int xfs_read_agf(struct xfs_mount *mp, struct xfs_trans *tp,
    117 			xfs_agnumber_t agno, int flags, struct xfs_buf **bpp);
    118 
    119 /*
    120  * Size of the unlinked inode hash table in the agi.
    121  */
    122 #define	XFS_AGI_UNLINKED_BUCKETS	64
    123 
    124 #define	XFS_AGI_MAGICNUM	0x00000001
    125 #define	XFS_AGI_VERSIONNUM	0x00000002
    126 #define	XFS_AGI_SEQNO		0x00000004
    127 #define	XFS_AGI_LENGTH		0x00000008
    128 #define	XFS_AGI_COUNT		0x00000010
    129 #define	XFS_AGI_ROOT		0x00000020
    130 #define	XFS_AGI_LEVEL		0x00000040
    131 #define	XFS_AGI_FREECOUNT	0x00000080
    132 #define	XFS_AGI_NEWINO		0x00000100
    133 #define	XFS_AGI_DIRINO		0x00000200
    134 #define	XFS_AGI_UNLINKED	0x00000400
    135 #define	XFS_AGI_NUM_BITS	11
    136 #define	XFS_AGI_ALL_BITS	((1 << XFS_AGI_NUM_BITS) - 1)
    137 
    138 /* disk block (xfs_daddr_t) in the AG */
    139 #define XFS_AGI_DADDR(mp)	((xfs_daddr_t)(2 << (mp)->m_sectbb_log))
    140 #define	XFS_AGI_BLOCK(mp)	XFS_HDR_BLOCK(mp, XFS_AGI_DADDR(mp))
    141 #define	XFS_BUF_TO_AGI(bp)	((xfs_agi_t *)((bp)->b_addr))
    142 
    143 extern int xfs_read_agi(struct xfs_mount *mp, struct xfs_trans *tp,
    144 				xfs_agnumber_t agno, struct xfs_buf **bpp);
    145 
    146 /*
    147  * The third a.g. block contains the a.g. freelist, an array
    148  * of block pointers to blocks owned by the allocation btree code.
    149  */
    150 #define XFS_AGFL_DADDR(mp)	((xfs_daddr_t)(3 << (mp)->m_sectbb_log))
    151 #define	XFS_AGFL_BLOCK(mp)	XFS_HDR_BLOCK(mp, XFS_AGFL_DADDR(mp))
    152 #define XFS_AGFL_SIZE(mp)	((mp)->m_sb.sb_sectsize / sizeof(xfs_agblock_t))
    153 #define	XFS_BUF_TO_AGFL(bp)	((xfs_agfl_t *)((bp)->b_addr))
    154 
    155 typedef struct xfs_agfl {
    156 	uint32_t		agfl_bno[1];	/* actually XFS_AGFL_SIZE(mp) */
    157 } xfs_agfl_t;
    158 
    159 /*
    160  * tags for inode radix tree
    161  */
    162 #define XFS_ICI_NO_TAG		(-1)	/* special flag for an untagged lookup
    163 					   in xfs_inode_ag_iterator */
    164 #define XFS_ICI_RECLAIM_TAG	0	/* inode is to be reclaimed */
    165 
    166 #define	XFS_AG_MAXLEVELS(mp)		((mp)->m_ag_maxlevels)
    167 #define	XFS_MIN_FREELIST_RAW(bl,cl,mp)	\
    168 	(MIN(bl + 1, XFS_AG_MAXLEVELS(mp)) + MIN(cl + 1, XFS_AG_MAXLEVELS(mp)))
    169 #define	XFS_MIN_FREELIST(a,mp)		\
    170 	(XFS_MIN_FREELIST_RAW(		\
    171 		be32_to_cpu((a)->agf_levels[XFS_BTNUM_BNOi]), \
    172 		be32_to_cpu((a)->agf_levels[XFS_BTNUM_CNTi]), mp))
    173 #define	XFS_MIN_FREELIST_PAG(pag,mp)	\
    174 	(XFS_MIN_FREELIST_RAW(		\
    175 		(unsigned int)(pag)->pagf_levels[XFS_BTNUM_BNOi], \
    176 		(unsigned int)(pag)->pagf_levels[XFS_BTNUM_CNTi], mp))
    177 
    178 /*
    179  * For checking for bad ranges of xfs_daddr_t's, covering multiple
    180  * allocation groups or a single xfs_daddr_t that's a superblock copy.
    181  */
    182 #define	XFS_AG_CHECK_DADDR(mp,d,len)	\
    183 	((len) == 1 ? \
    184 	    ASSERT((d) == XFS_SB_DADDR || \
    185 		   xfs_daddr_to_agbno(mp, d) != XFS_SB_DADDR) : \
    186 	    ASSERT(xfs_daddr_to_agno(mp, d) == \
    187 		   xfs_daddr_to_agno(mp, (d) + (len) - 1)))
    188 
    189 #endif	/* XFS_AG_H_ */
    190