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)

#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__ */