linux/fs/xfs/xfs_ag.h
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   1/*
   2 * Copyright (c) 2000-2003,2005 Silicon Graphics, Inc.
   3 * All Rights Reserved.
   4 *
   5 * This program is free software; you can redistribute it and/or
   6 * modify it under the terms of the GNU General Public License as
   7 * published by the Free Software Foundation.
   8 *
   9 * This program is distributed in the hope that it would be useful,
  10 * but WITHOUT ANY WARRANTY; without even the implied warranty of
  11 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  12 * GNU General Public License for more details.
  13 *
  14 * You should have received a copy of the GNU General Public License
  15 * along with this program; if not, write the Free Software Foundation,
  16 * Inc.,  51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
  17 */
  18#ifndef __XFS_AG_H__
  19#define __XFS_AG_H__
  20
  21/*
  22 * Allocation group header
  23 * This is divided into three structures, placed in sequential 512-byte
  24 * buffers after a copy of the superblock (also in a 512-byte buffer).
  25 */
  26
  27struct xfs_buf;
  28struct xfs_mount;
  29struct xfs_trans;
  30
  31#define XFS_AGF_MAGIC   0x58414746      /* 'XAGF' */
  32#define XFS_AGI_MAGIC   0x58414749      /* 'XAGI' */
  33#define XFS_AGF_VERSION 1
  34#define XFS_AGI_VERSION 1
  35
  36#define XFS_AGF_GOOD_VERSION(v) ((v) == XFS_AGF_VERSION)
  37#define XFS_AGI_GOOD_VERSION(v) ((v) == XFS_AGI_VERSION)
  38
  39/*
  40 * Btree number 0 is bno, 1 is cnt.  This value gives the size of the
  41 * arrays below.
  42 */
  43#define XFS_BTNUM_AGF   ((int)XFS_BTNUM_CNTi + 1)
  44
  45/*
  46 * The second word of agf_levels in the first a.g. overlaps the EFS
  47 * superblock's magic number.  Since the magic numbers valid for EFS
  48 * are > 64k, our value cannot be confused for an EFS superblock's.
  49 */
  50
  51typedef struct xfs_agf {
  52        /*
  53         * Common allocation group header information
  54         */
  55        __be32          agf_magicnum;   /* magic number == XFS_AGF_MAGIC */
  56        __be32          agf_versionnum; /* header version == XFS_AGF_VERSION */
  57        __be32          agf_seqno;      /* sequence # starting from 0 */
  58        __be32          agf_length;     /* size in blocks of a.g. */
  59        /*
  60         * Freespace information
  61         */
  62        __be32          agf_roots[XFS_BTNUM_AGF];       /* root blocks */
  63        __be32          agf_spare0;     /* spare field */
  64        __be32          agf_levels[XFS_BTNUM_AGF];      /* btree levels */
  65        __be32          agf_spare1;     /* spare field */
  66        __be32          agf_flfirst;    /* first freelist block's index */
  67        __be32          agf_fllast;     /* last freelist block's index */
  68        __be32          agf_flcount;    /* count of blocks in freelist */
  69        __be32          agf_freeblks;   /* total free blocks */
  70        __be32          agf_longest;    /* longest free space */
  71        __be32          agf_btreeblks;  /* # of blocks held in AGF btrees */
  72} xfs_agf_t;
  73
  74#define XFS_AGF_MAGICNUM        0x00000001
  75#define XFS_AGF_VERSIONNUM      0x00000002
  76#define XFS_AGF_SEQNO           0x00000004
  77#define XFS_AGF_LENGTH          0x00000008
  78#define XFS_AGF_ROOTS           0x00000010
  79#define XFS_AGF_LEVELS          0x00000020
  80#define XFS_AGF_FLFIRST         0x00000040
  81#define XFS_AGF_FLLAST          0x00000080
  82#define XFS_AGF_FLCOUNT         0x00000100
  83#define XFS_AGF_FREEBLKS        0x00000200
  84#define XFS_AGF_LONGEST         0x00000400
  85#define XFS_AGF_BTREEBLKS       0x00000800
  86#define XFS_AGF_NUM_BITS        12
  87#define XFS_AGF_ALL_BITS        ((1 << XFS_AGF_NUM_BITS) - 1)
  88
  89#define XFS_AGF_FLAGS \
  90        { XFS_AGF_MAGICNUM,     "MAGICNUM" }, \
  91        { XFS_AGF_VERSIONNUM,   "VERSIONNUM" }, \
  92        { XFS_AGF_SEQNO,        "SEQNO" }, \
  93        { XFS_AGF_LENGTH,       "LENGTH" }, \
  94        { XFS_AGF_ROOTS,        "ROOTS" }, \
  95        { XFS_AGF_LEVELS,       "LEVELS" }, \
  96        { XFS_AGF_FLFIRST,      "FLFIRST" }, \
  97        { XFS_AGF_FLLAST,       "FLLAST" }, \
  98        { XFS_AGF_FLCOUNT,      "FLCOUNT" }, \
  99        { XFS_AGF_FREEBLKS,     "FREEBLKS" }, \
 100        { XFS_AGF_LONGEST,      "LONGEST" }, \
 101        { XFS_AGF_BTREEBLKS,    "BTREEBLKS" }
 102
 103/* disk block (xfs_daddr_t) in the AG */
 104#define XFS_AGF_DADDR(mp)       ((xfs_daddr_t)(1 << (mp)->m_sectbb_log))
 105#define XFS_AGF_BLOCK(mp)       XFS_HDR_BLOCK(mp, XFS_AGF_DADDR(mp))
 106#define XFS_BUF_TO_AGF(bp)      ((xfs_agf_t *)((bp)->b_addr))
 107
 108extern int xfs_read_agf(struct xfs_mount *mp, struct xfs_trans *tp,
 109                        xfs_agnumber_t agno, int flags, struct xfs_buf **bpp);
 110
 111extern const struct xfs_buf_ops xfs_agf_buf_ops;
 112
 113/*
 114 * Size of the unlinked inode hash table in the agi.
 115 */
 116#define XFS_AGI_UNLINKED_BUCKETS        64
 117
 118typedef struct xfs_agi {
 119        /*
 120         * Common allocation group header information
 121         */
 122        __be32          agi_magicnum;   /* magic number == XFS_AGI_MAGIC */
 123        __be32          agi_versionnum; /* header version == XFS_AGI_VERSION */
 124        __be32          agi_seqno;      /* sequence # starting from 0 */
 125        __be32          agi_length;     /* size in blocks of a.g. */
 126        /*
 127         * Inode information
 128         * Inodes are mapped by interpreting the inode number, so no
 129         * mapping data is needed here.
 130         */
 131        __be32          agi_count;      /* count of allocated inodes */
 132        __be32          agi_root;       /* root of inode btree */
 133        __be32          agi_level;      /* levels in inode btree */
 134        __be32          agi_freecount;  /* number of free inodes */
 135        __be32          agi_newino;     /* new inode just allocated */
 136        __be32          agi_dirino;     /* last directory inode chunk */
 137        /*
 138         * Hash table of inodes which have been unlinked but are
 139         * still being referenced.
 140         */
 141        __be32          agi_unlinked[XFS_AGI_UNLINKED_BUCKETS];
 142} xfs_agi_t;
 143
 144#define XFS_AGI_MAGICNUM        0x00000001
 145#define XFS_AGI_VERSIONNUM      0x00000002
 146#define XFS_AGI_SEQNO           0x00000004
 147#define XFS_AGI_LENGTH          0x00000008
 148#define XFS_AGI_COUNT           0x00000010
 149#define XFS_AGI_ROOT            0x00000020
 150#define XFS_AGI_LEVEL           0x00000040
 151#define XFS_AGI_FREECOUNT       0x00000080
 152#define XFS_AGI_NEWINO          0x00000100
 153#define XFS_AGI_DIRINO          0x00000200
 154#define XFS_AGI_UNLINKED        0x00000400
 155#define XFS_AGI_NUM_BITS        11
 156#define XFS_AGI_ALL_BITS        ((1 << XFS_AGI_NUM_BITS) - 1)
 157
 158/* disk block (xfs_daddr_t) in the AG */
 159#define XFS_AGI_DADDR(mp)       ((xfs_daddr_t)(2 << (mp)->m_sectbb_log))
 160#define XFS_AGI_BLOCK(mp)       XFS_HDR_BLOCK(mp, XFS_AGI_DADDR(mp))
 161#define XFS_BUF_TO_AGI(bp)      ((xfs_agi_t *)((bp)->b_addr))
 162
 163extern int xfs_read_agi(struct xfs_mount *mp, struct xfs_trans *tp,
 164                                xfs_agnumber_t agno, struct xfs_buf **bpp);
 165
 166extern const struct xfs_buf_ops xfs_agi_buf_ops;
 167
 168/*
 169 * The third a.g. block contains the a.g. freelist, an array
 170 * of block pointers to blocks owned by the allocation btree code.
 171 */
 172#define XFS_AGFL_DADDR(mp)      ((xfs_daddr_t)(3 << (mp)->m_sectbb_log))
 173#define XFS_AGFL_BLOCK(mp)      XFS_HDR_BLOCK(mp, XFS_AGFL_DADDR(mp))
 174#define XFS_AGFL_SIZE(mp)       ((mp)->m_sb.sb_sectsize / sizeof(xfs_agblock_t))
 175#define XFS_BUF_TO_AGFL(bp)     ((xfs_agfl_t *)((bp)->b_addr))
 176
 177typedef struct xfs_agfl {
 178        __be32          agfl_bno[1];    /* actually XFS_AGFL_SIZE(mp) */
 179} xfs_agfl_t;
 180
 181/*
 182 * Per-ag incore structure, copies of information in agf and agi,
 183 * to improve the performance of allocation group selection.
 184 */
 185#define XFS_PAGB_NUM_SLOTS      128
 186
 187typedef struct xfs_perag {
 188        struct xfs_mount *pag_mount;    /* owner filesystem */
 189        xfs_agnumber_t  pag_agno;       /* AG this structure belongs to */
 190        atomic_t        pag_ref;        /* perag reference count */
 191        char            pagf_init;      /* this agf's entry is initialized */
 192        char            pagi_init;      /* this agi's entry is initialized */
 193        char            pagf_metadata;  /* the agf is preferred to be metadata */
 194        char            pagi_inodeok;   /* The agi is ok for inodes */
 195        __uint8_t       pagf_levels[XFS_BTNUM_AGF];
 196                                        /* # of levels in bno & cnt btree */
 197        __uint32_t      pagf_flcount;   /* count of blocks in freelist */
 198        xfs_extlen_t    pagf_freeblks;  /* total free blocks */
 199        xfs_extlen_t    pagf_longest;   /* longest free space */
 200        __uint32_t      pagf_btreeblks; /* # of blocks held in AGF btrees */
 201        xfs_agino_t     pagi_freecount; /* number of free inodes */
 202        xfs_agino_t     pagi_count;     /* number of allocated inodes */
 203
 204        /*
 205         * Inode allocation search lookup optimisation.
 206         * If the pagino matches, the search for new inodes
 207         * doesn't need to search the near ones again straight away
 208         */
 209        xfs_agino_t     pagl_pagino;
 210        xfs_agino_t     pagl_leftrec;
 211        xfs_agino_t     pagl_rightrec;
 212#ifdef __KERNEL__
 213        spinlock_t      pagb_lock;      /* lock for pagb_tree */
 214        struct rb_root  pagb_tree;      /* ordered tree of busy extents */
 215
 216        atomic_t        pagf_fstrms;    /* # of filestreams active in this AG */
 217
 218        spinlock_t      pag_ici_lock;   /* incore inode cache lock */
 219        struct radix_tree_root pag_ici_root;    /* incore inode cache root */
 220        int             pag_ici_reclaimable;    /* reclaimable inodes */
 221        struct mutex    pag_ici_reclaim_lock;   /* serialisation point */
 222        unsigned long   pag_ici_reclaim_cursor; /* reclaim restart point */
 223
 224        /* buffer cache index */
 225        spinlock_t      pag_buf_lock;   /* lock for pag_buf_tree */
 226        struct rb_root  pag_buf_tree;   /* ordered tree of active buffers */
 227
 228        /* for rcu-safe freeing */
 229        struct rcu_head rcu_head;
 230#endif
 231        int             pagb_count;     /* pagb slots in use */
 232} xfs_perag_t;
 233
 234/*
 235 * tags for inode radix tree
 236 */
 237#define XFS_ICI_NO_TAG          (-1)    /* special flag for an untagged lookup
 238                                           in xfs_inode_ag_iterator */
 239#define XFS_ICI_RECLAIM_TAG     0       /* inode is to be reclaimed */
 240#define XFS_ICI_EOFBLOCKS_TAG   1       /* inode has blocks beyond EOF */
 241
 242#define XFS_AG_MAXLEVELS(mp)            ((mp)->m_ag_maxlevels)
 243#define XFS_MIN_FREELIST_RAW(bl,cl,mp)  \
 244        (MIN(bl + 1, XFS_AG_MAXLEVELS(mp)) + MIN(cl + 1, XFS_AG_MAXLEVELS(mp)))
 245#define XFS_MIN_FREELIST(a,mp)          \
 246        (XFS_MIN_FREELIST_RAW(          \
 247                be32_to_cpu((a)->agf_levels[XFS_BTNUM_BNOi]), \
 248                be32_to_cpu((a)->agf_levels[XFS_BTNUM_CNTi]), mp))
 249#define XFS_MIN_FREELIST_PAG(pag,mp)    \
 250        (XFS_MIN_FREELIST_RAW(          \
 251                (unsigned int)(pag)->pagf_levels[XFS_BTNUM_BNOi], \
 252                (unsigned int)(pag)->pagf_levels[XFS_BTNUM_CNTi], mp))
 253
 254#define XFS_AGB_TO_FSB(mp,agno,agbno)   \
 255        (((xfs_fsblock_t)(agno) << (mp)->m_sb.sb_agblklog) | (agbno))
 256#define XFS_FSB_TO_AGNO(mp,fsbno)       \
 257        ((xfs_agnumber_t)((fsbno) >> (mp)->m_sb.sb_agblklog))
 258#define XFS_FSB_TO_AGBNO(mp,fsbno)      \
 259        ((xfs_agblock_t)((fsbno) & xfs_mask32lo((mp)->m_sb.sb_agblklog)))
 260#define XFS_AGB_TO_DADDR(mp,agno,agbno) \
 261        ((xfs_daddr_t)XFS_FSB_TO_BB(mp, \
 262                (xfs_fsblock_t)(agno) * (mp)->m_sb.sb_agblocks + (agbno)))
 263#define XFS_AG_DADDR(mp,agno,d)         (XFS_AGB_TO_DADDR(mp, agno, 0) + (d))
 264
 265/*
 266 * For checking for bad ranges of xfs_daddr_t's, covering multiple
 267 * allocation groups or a single xfs_daddr_t that's a superblock copy.
 268 */
 269#define XFS_AG_CHECK_DADDR(mp,d,len)    \
 270        ((len) == 1 ? \
 271            ASSERT((d) == XFS_SB_DADDR || \
 272                   xfs_daddr_to_agbno(mp, d) != XFS_SB_DADDR) : \
 273            ASSERT(xfs_daddr_to_agno(mp, d) == \
 274                   xfs_daddr_to_agno(mp, (d) + (len) - 1)))
 275
 276#endif  /* __XFS_AG_H__ */
 277
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