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
 111/*
 112 * Size of the unlinked inode hash table in the agi.
 113 */
 114#define XFS_AGI_UNLINKED_BUCKETS        64
 115
 116typedef struct xfs_agi {
 117        /*
 118         * Common allocation group header information
 119         */
 120        __be32          agi_magicnum;   /* magic number == XFS_AGI_MAGIC */
 121        __be32          agi_versionnum; /* header version == XFS_AGI_VERSION */
 122        __be32          agi_seqno;      /* sequence # starting from 0 */
 123        __be32          agi_length;     /* size in blocks of a.g. */
 124        /*
 125         * Inode information
 126         * Inodes are mapped by interpreting the inode number, so no
 127         * mapping data is needed here.
 128         */
 129        __be32          agi_count;      /* count of allocated inodes */
 130        __be32          agi_root;       /* root of inode btree */
 131        __be32          agi_level;      /* levels in inode btree */
 132        __be32          agi_freecount;  /* number of free inodes */
 133        __be32          agi_newino;     /* new inode just allocated */
 134        __be32          agi_dirino;     /* last directory inode chunk */
 135        /*
 136         * Hash table of inodes which have been unlinked but are
 137         * still being referenced.
 138         */
 139        __be32          agi_unlinked[XFS_AGI_UNLINKED_BUCKETS];
 140} xfs_agi_t;
 141
 142#define XFS_AGI_MAGICNUM        0x00000001
 143#define XFS_AGI_VERSIONNUM      0x00000002
 144#define XFS_AGI_SEQNO           0x00000004
 145#define XFS_AGI_LENGTH          0x00000008
 146#define XFS_AGI_COUNT           0x00000010
 147#define XFS_AGI_ROOT            0x00000020
 148#define XFS_AGI_LEVEL           0x00000040
 149#define XFS_AGI_FREECOUNT       0x00000080
 150#define XFS_AGI_NEWINO          0x00000100
 151#define XFS_AGI_DIRINO          0x00000200
 152#define XFS_AGI_UNLINKED        0x00000400
 153#define XFS_AGI_NUM_BITS        11
 154#define XFS_AGI_ALL_BITS        ((1 << XFS_AGI_NUM_BITS) - 1)
 155
 156/* disk block (xfs_daddr_t) in the AG */
 157#define XFS_AGI_DADDR(mp)       ((xfs_daddr_t)(2 << (mp)->m_sectbb_log))
 158#define XFS_AGI_BLOCK(mp)       XFS_HDR_BLOCK(mp, XFS_AGI_DADDR(mp))
 159#define XFS_BUF_TO_AGI(bp)      ((xfs_agi_t *)((bp)->b_addr))
 160
 161extern int xfs_read_agi(struct xfs_mount *mp, struct xfs_trans *tp,
 162                                xfs_agnumber_t agno, struct xfs_buf **bpp);
 163
 164/*
 165 * The third a.g. block contains the a.g. freelist, an array
 166 * of block pointers to blocks owned by the allocation btree code.
 167 */
 168#define XFS_AGFL_DADDR(mp)      ((xfs_daddr_t)(3 << (mp)->m_sectbb_log))
 169#define XFS_AGFL_BLOCK(mp)      XFS_HDR_BLOCK(mp, XFS_AGFL_DADDR(mp))
 170#define XFS_AGFL_SIZE(mp)       ((mp)->m_sb.sb_sectsize / sizeof(xfs_agblock_t))
 171#define XFS_BUF_TO_AGFL(bp)     ((xfs_agfl_t *)((bp)->b_addr))
 172
 173typedef struct xfs_agfl {
 174        __be32          agfl_bno[1];    /* actually XFS_AGFL_SIZE(mp) */
 175} xfs_agfl_t;
 176
 177/*
 178 * Per-ag incore structure, copies of information in agf and agi,
 179 * to improve the performance of allocation group selection.
 180 */
 181#define XFS_PAGB_NUM_SLOTS      128
 182
 183typedef struct xfs_perag {
 184        struct xfs_mount *pag_mount;    /* owner filesystem */
 185        xfs_agnumber_t  pag_agno;       /* AG this structure belongs to */
 186        atomic_t        pag_ref;        /* perag reference count */
 187        char            pagf_init;      /* this agf's entry is initialized */
 188        char            pagi_init;      /* this agi's entry is initialized */
 189        char            pagf_metadata;  /* the agf is preferred to be metadata */
 190        char            pagi_inodeok;   /* The agi is ok for inodes */
 191        __uint8_t       pagf_levels[XFS_BTNUM_AGF];
 192                                        /* # of levels in bno & cnt btree */
 193        __uint32_t      pagf_flcount;   /* count of blocks in freelist */
 194        xfs_extlen_t    pagf_freeblks;  /* total free blocks */
 195        xfs_extlen_t    pagf_longest;   /* longest free space */
 196        __uint32_t      pagf_btreeblks; /* # of blocks held in AGF btrees */
 197        xfs_agino_t     pagi_freecount; /* number of free inodes */
 198        xfs_agino_t     pagi_count;     /* number of allocated inodes */
 199
 200        /*
 201         * Inode allocation search lookup optimisation.
 202         * If the pagino matches, the search for new inodes
 203         * doesn't need to search the near ones again straight away
 204         */
 205        xfs_agino_t     pagl_pagino;
 206        xfs_agino_t     pagl_leftrec;
 207        xfs_agino_t     pagl_rightrec;
 208#ifdef __KERNEL__
 209        spinlock_t      pagb_lock;      /* lock for pagb_tree */
 210        struct rb_root  pagb_tree;      /* ordered tree of busy extents */
 211
 212        atomic_t        pagf_fstrms;    /* # of filestreams active in this AG */
 213
 214        spinlock_t      pag_ici_lock;   /* incore inode cache lock */
 215        struct radix_tree_root pag_ici_root;    /* incore inode cache root */
 216        int             pag_ici_reclaimable;    /* reclaimable inodes */
 217        struct mutex    pag_ici_reclaim_lock;   /* serialisation point */
 218        unsigned long   pag_ici_reclaim_cursor; /* reclaim restart point */
 219
 220        /* buffer cache index */
 221        spinlock_t      pag_buf_lock;   /* lock for pag_buf_tree */
 222        struct rb_root  pag_buf_tree;   /* ordered tree of active buffers */
 223
 224        /* for rcu-safe freeing */
 225        struct rcu_head rcu_head;
 226#endif
 227        int             pagb_count;     /* pagb slots in use */
 228} xfs_perag_t;
 229
 230/*
 231 * tags for inode radix tree
 232 */
 233#define XFS_ICI_NO_TAG          (-1)    /* special flag for an untagged lookup
 234                                           in xfs_inode_ag_iterator */
 235#define XFS_ICI_RECLAIM_TAG     0       /* inode is to be reclaimed */
 236
 237#define XFS_AG_MAXLEVELS(mp)            ((mp)->m_ag_maxlevels)
 238#define XFS_MIN_FREELIST_RAW(bl,cl,mp)  \
 239        (MIN(bl + 1, XFS_AG_MAXLEVELS(mp)) + MIN(cl + 1, XFS_AG_MAXLEVELS(mp)))
 240#define XFS_MIN_FREELIST(a,mp)          \
 241        (XFS_MIN_FREELIST_RAW(          \
 242                be32_to_cpu((a)->agf_levels[XFS_BTNUM_BNOi]), \
 243                be32_to_cpu((a)->agf_levels[XFS_BTNUM_CNTi]), mp))
 244#define XFS_MIN_FREELIST_PAG(pag,mp)    \
 245        (XFS_MIN_FREELIST_RAW(          \
 246                (unsigned int)(pag)->pagf_levels[XFS_BTNUM_BNOi], \
 247                (unsigned int)(pag)->pagf_levels[XFS_BTNUM_CNTi], mp))
 248
 249#define XFS_AGB_TO_FSB(mp,agno,agbno)   \
 250        (((xfs_fsblock_t)(agno) << (mp)->m_sb.sb_agblklog) | (agbno))
 251#define XFS_FSB_TO_AGNO(mp,fsbno)       \
 252        ((xfs_agnumber_t)((fsbno) >> (mp)->m_sb.sb_agblklog))
 253#define XFS_FSB_TO_AGBNO(mp,fsbno)      \
 254        ((xfs_agblock_t)((fsbno) & xfs_mask32lo((mp)->m_sb.sb_agblklog)))
 255#define XFS_AGB_TO_DADDR(mp,agno,agbno) \
 256        ((xfs_daddr_t)XFS_FSB_TO_BB(mp, \
 257                (xfs_fsblock_t)(agno) * (mp)->m_sb.sb_agblocks + (agbno)))
 258#define XFS_AG_DADDR(mp,agno,d)         (XFS_AGB_TO_DADDR(mp, agno, 0) + (d))
 259
 260/*
 261 * For checking for bad ranges of xfs_daddr_t's, covering multiple
 262 * allocation groups or a single xfs_daddr_t that's a superblock copy.
 263 */
 264#define XFS_AG_CHECK_DADDR(mp,d,len)    \
 265        ((len) == 1 ? \
 266            ASSERT((d) == XFS_SB_DADDR || \
 267                   xfs_daddr_to_agbno(mp, d) != XFS_SB_DADDR) : \
 268            ASSERT(xfs_daddr_to_agno(mp, d) == \
 269                   xfs_daddr_to_agno(mp, (d) + (len) - 1)))
 270
 271#endif  /* __XFS_AG_H__ */
 272
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