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root/fs/xfs/xfs_ag.h

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/*
 * 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)

/* 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 *)XFS_BUF_PTR(bp))


/*
 * 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 *)XFS_BUF_PTR(bp))

/*
 * 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 *)XFS_BUF_PTR(bp))

typedef struct xfs_agfl {
        __be32          agfl_bno[1];    /* actually XFS_AGFL_SIZE(mp) */
} xfs_agfl_t;

/*
 * Busy block/extent entry.  Used in perag to mark blocks that have been freed
 * but whose transactions aren't committed to disk yet.
 */
typedef struct xfs_perag_busy {
        xfs_agblock_t   busy_start;
        xfs_extlen_t    busy_length;
        struct xfs_trans *busy_tp;      /* transaction that did the free */
} xfs_perag_busy_t;

/*
 * Per-ag incore structure, copies of information in agf and agi,
 * to improve the performance of allocation group selection.
 *
 * pick sizes which fit in allocation buckets well
 */
#if (BITS_PER_LONG == 32)
#define XFS_PAGB_NUM_SLOTS      84
#elif (BITS_PER_LONG == 64)
#define XFS_PAGB_NUM_SLOTS      128
#endif

typedef struct xfs_perag
{
        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 */
        int             pagb_count;     /* pagb slots in use */
#ifdef __KERNEL__
        spinlock_t      pagb_lock;      /* lock for pagb_list */
#endif
        xfs_perag_busy_t *pagb_list;    /* unstable blocks */
        atomic_t        pagf_fstrms;    /* # of filestreams active in this AG */

        int             pag_ici_init;   /* incore inode cache initialised */
        rwlock_t        pag_ici_lock;   /* incore inode lock */
        struct radix_tree_root pag_ici_root;    /* incore inode cache root */
} xfs_perag_t;

#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(          \
                (uint_t)(pag)->pagf_levels[XFS_BTNUM_BNOi], \
                (uint_t)(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__ */

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