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_AGFL_MAGIC  0x5841464c      /* 'XAFL' */
  34#define XFS_AGF_VERSION 1
  35#define XFS_AGI_VERSION 1
  36
  37#define XFS_AGF_GOOD_VERSION(v) ((v) == XFS_AGF_VERSION)
  38#define XFS_AGI_GOOD_VERSION(v) ((v) == XFS_AGI_VERSION)
  39
  40/*
  41 * Btree number 0 is bno, 1 is cnt.  This value gives the size of the
  42 * arrays below.
  43 */
  44#define XFS_BTNUM_AGF   ((int)XFS_BTNUM_CNTi + 1)
  45
  46/*
  47 * The second word of agf_levels in the first a.g. overlaps the EFS
  48 * superblock's magic number.  Since the magic numbers valid for EFS
  49 * are > 64k, our value cannot be confused for an EFS superblock's.
  50 */
  51
  52typedef struct xfs_agf {
  53        /*
  54         * Common allocation group header information
  55         */
  56        __be32          agf_magicnum;   /* magic number == XFS_AGF_MAGIC */
  57        __be32          agf_versionnum; /* header version == XFS_AGF_VERSION */
  58        __be32          agf_seqno;      /* sequence # starting from 0 */
  59        __be32          agf_length;     /* size in blocks of a.g. */
  60        /*
  61         * Freespace information
  62         */
  63        __be32          agf_roots[XFS_BTNUM_AGF];       /* root blocks */
  64        __be32          agf_spare0;     /* spare field */
  65        __be32          agf_levels[XFS_BTNUM_AGF];      /* btree levels */
  66        __be32          agf_spare1;     /* spare field */
  67
  68        __be32          agf_flfirst;    /* first freelist block's index */
  69        __be32          agf_fllast;     /* last freelist block's index */
  70        __be32          agf_flcount;    /* count of blocks in freelist */
  71        __be32          agf_freeblks;   /* total free blocks */
  72
  73        __be32          agf_longest;    /* longest free space */
  74        __be32          agf_btreeblks;  /* # of blocks held in AGF btrees */
  75        uuid_t          agf_uuid;       /* uuid of filesystem */
  76
  77        /*
  78         * reserve some contiguous space for future logged fields before we add
  79         * the unlogged fields. This makes the range logging via flags and
  80         * structure offsets much simpler.
  81         */
  82        __be64          agf_spare64[16];
  83
  84        /* unlogged fields, written during buffer writeback. */
  85        __be64          agf_lsn;        /* last write sequence */
  86        __be32          agf_crc;        /* crc of agf sector */
  87        __be32          agf_spare2;
  88
  89        /* structure must be padded to 64 bit alignment */
  90} xfs_agf_t;
  91
  92#define XFS_AGF_MAGICNUM        0x00000001
  93#define XFS_AGF_VERSIONNUM      0x00000002
  94#define XFS_AGF_SEQNO           0x00000004
  95#define XFS_AGF_LENGTH          0x00000008
  96#define XFS_AGF_ROOTS           0x00000010
  97#define XFS_AGF_LEVELS          0x00000020
  98#define XFS_AGF_FLFIRST         0x00000040
  99#define XFS_AGF_FLLAST          0x00000080
 100#define XFS_AGF_FLCOUNT         0x00000100
 101#define XFS_AGF_FREEBLKS        0x00000200
 102#define XFS_AGF_LONGEST         0x00000400
 103#define XFS_AGF_BTREEBLKS       0x00000800
 104#define XFS_AGF_UUID            0x00001000
 105#define XFS_AGF_NUM_BITS        13
 106#define XFS_AGF_ALL_BITS        ((1 << XFS_AGF_NUM_BITS) - 1)
 107
 108#define XFS_AGF_FLAGS \
 109        { XFS_AGF_MAGICNUM,     "MAGICNUM" }, \
 110        { XFS_AGF_VERSIONNUM,   "VERSIONNUM" }, \
 111        { XFS_AGF_SEQNO,        "SEQNO" }, \
 112        { XFS_AGF_LENGTH,       "LENGTH" }, \
 113        { XFS_AGF_ROOTS,        "ROOTS" }, \
 114        { XFS_AGF_LEVELS,       "LEVELS" }, \
 115        { XFS_AGF_FLFIRST,      "FLFIRST" }, \
 116        { XFS_AGF_FLLAST,       "FLLAST" }, \
 117        { XFS_AGF_FLCOUNT,      "FLCOUNT" }, \
 118        { XFS_AGF_FREEBLKS,     "FREEBLKS" }, \
 119        { XFS_AGF_LONGEST,      "LONGEST" }, \
 120        { XFS_AGF_BTREEBLKS,    "BTREEBLKS" }, \
 121        { XFS_AGF_UUID,         "UUID" }
 122
 123/* disk block (xfs_daddr_t) in the AG */
 124#define XFS_AGF_DADDR(mp)       ((xfs_daddr_t)(1 << (mp)->m_sectbb_log))
 125#define XFS_AGF_BLOCK(mp)       XFS_HDR_BLOCK(mp, XFS_AGF_DADDR(mp))
 126#define XFS_BUF_TO_AGF(bp)      ((xfs_agf_t *)((bp)->b_addr))
 127
 128extern int xfs_read_agf(struct xfs_mount *mp, struct xfs_trans *tp,
 129                        xfs_agnumber_t agno, int flags, struct xfs_buf **bpp);
 130
 131extern const struct xfs_buf_ops xfs_agf_buf_ops;
 132
 133/*
 134 * Size of the unlinked inode hash table in the agi.
 135 */
 136#define XFS_AGI_UNLINKED_BUCKETS        64
 137
 138typedef struct xfs_agi {
 139        /*
 140         * Common allocation group header information
 141         */
 142        __be32          agi_magicnum;   /* magic number == XFS_AGI_MAGIC */
 143        __be32          agi_versionnum; /* header version == XFS_AGI_VERSION */
 144        __be32          agi_seqno;      /* sequence # starting from 0 */
 145        __be32          agi_length;     /* size in blocks of a.g. */
 146        /*
 147         * Inode information
 148         * Inodes are mapped by interpreting the inode number, so no
 149         * mapping data is needed here.
 150         */
 151        __be32          agi_count;      /* count of allocated inodes */
 152        __be32          agi_root;       /* root of inode btree */
 153        __be32          agi_level;      /* levels in inode btree */
 154        __be32          agi_freecount;  /* number of free inodes */
 155
 156        __be32          agi_newino;     /* new inode just allocated */
 157        __be32          agi_dirino;     /* last directory inode chunk */
 158        /*
 159         * Hash table of inodes which have been unlinked but are
 160         * still being referenced.
 161         */
 162        __be32          agi_unlinked[XFS_AGI_UNLINKED_BUCKETS];
 163
 164        uuid_t          agi_uuid;       /* uuid of filesystem */
 165        __be32          agi_crc;        /* crc of agi sector */
 166        __be32          agi_pad32;
 167        __be64          agi_lsn;        /* last write sequence */
 168
 169        /* structure must be padded to 64 bit alignment */
 170} xfs_agi_t;
 171
 172#define XFS_AGI_MAGICNUM        0x00000001
 173#define XFS_AGI_VERSIONNUM      0x00000002
 174#define XFS_AGI_SEQNO           0x00000004
 175#define XFS_AGI_LENGTH          0x00000008
 176#define XFS_AGI_COUNT           0x00000010
 177#define XFS_AGI_ROOT            0x00000020
 178#define XFS_AGI_LEVEL           0x00000040
 179#define XFS_AGI_FREECOUNT       0x00000080
 180#define XFS_AGI_NEWINO          0x00000100
 181#define XFS_AGI_DIRINO          0x00000200
 182#define XFS_AGI_UNLINKED        0x00000400
 183#define XFS_AGI_NUM_BITS        11
 184#define XFS_AGI_ALL_BITS        ((1 << XFS_AGI_NUM_BITS) - 1)
 185
 186/* disk block (xfs_daddr_t) in the AG */
 187#define XFS_AGI_DADDR(mp)       ((xfs_daddr_t)(2 << (mp)->m_sectbb_log))
 188#define XFS_AGI_BLOCK(mp)       XFS_HDR_BLOCK(mp, XFS_AGI_DADDR(mp))
 189#define XFS_BUF_TO_AGI(bp)      ((xfs_agi_t *)((bp)->b_addr))
 190
 191extern int xfs_read_agi(struct xfs_mount *mp, struct xfs_trans *tp,
 192                                xfs_agnumber_t agno, struct xfs_buf **bpp);
 193
 194extern const struct xfs_buf_ops xfs_agi_buf_ops;
 195
 196/*
 197 * The third a.g. block contains the a.g. freelist, an array
 198 * of block pointers to blocks owned by the allocation btree code.
 199 */
 200#define XFS_AGFL_DADDR(mp)      ((xfs_daddr_t)(3 << (mp)->m_sectbb_log))
 201#define XFS_AGFL_BLOCK(mp)      XFS_HDR_BLOCK(mp, XFS_AGFL_DADDR(mp))
 202#define XFS_BUF_TO_AGFL(bp)     ((xfs_agfl_t *)((bp)->b_addr))
 203
 204#define XFS_BUF_TO_AGFL_BNO(mp, bp) \
 205        (xfs_sb_version_hascrc(&((mp)->m_sb)) ? \
 206                &(XFS_BUF_TO_AGFL(bp)->agfl_bno[0]) : \
 207                (__be32 *)(bp)->b_addr)
 208
 209/*
 210 * Size of the AGFL.  For CRC-enabled filesystes we steal a couple of
 211 * slots in the beginning of the block for a proper header with the
 212 * location information and CRC.
 213 */
 214#define XFS_AGFL_SIZE(mp) \
 215        (((mp)->m_sb.sb_sectsize - \
 216         (xfs_sb_version_hascrc(&((mp)->m_sb)) ? \
 217                sizeof(struct xfs_agfl) : 0)) / \
 218          sizeof(xfs_agblock_t))
 219
 220typedef struct xfs_agfl {
 221        __be32          agfl_magicnum;
 222        __be32          agfl_seqno;
 223        uuid_t          agfl_uuid;
 224        __be64          agfl_lsn;
 225        __be32          agfl_crc;
 226        __be32          agfl_bno[];     /* actually XFS_AGFL_SIZE(mp) */
 227} xfs_agfl_t;
 228
 229/*
 230 * Per-ag incore structure, copies of information in agf and agi,
 231 * to improve the performance of allocation group selection.
 232 */
 233#define XFS_PAGB_NUM_SLOTS      128
 234
 235typedef struct xfs_perag {
 236        struct xfs_mount *pag_mount;    /* owner filesystem */
 237        xfs_agnumber_t  pag_agno;       /* AG this structure belongs to */
 238        atomic_t        pag_ref;        /* perag reference count */
 239        char            pagf_init;      /* this agf's entry is initialized */
 240        char            pagi_init;      /* this agi's entry is initialized */
 241        char            pagf_metadata;  /* the agf is preferred to be metadata */
 242        char            pagi_inodeok;   /* The agi is ok for inodes */
 243        __uint8_t       pagf_levels[XFS_BTNUM_AGF];
 244                                        /* # of levels in bno & cnt btree */
 245        __uint32_t      pagf_flcount;   /* count of blocks in freelist */
 246        xfs_extlen_t    pagf_freeblks;  /* total free blocks */
 247        xfs_extlen_t    pagf_longest;   /* longest free space */
 248        __uint32_t      pagf_btreeblks; /* # of blocks held in AGF btrees */
 249        xfs_agino_t     pagi_freecount; /* number of free inodes */
 250        xfs_agino_t     pagi_count;     /* number of allocated inodes */
 251
 252        /*
 253         * Inode allocation search lookup optimisation.
 254         * If the pagino matches, the search for new inodes
 255         * doesn't need to search the near ones again straight away
 256         */
 257        xfs_agino_t     pagl_pagino;
 258        xfs_agino_t     pagl_leftrec;
 259        xfs_agino_t     pagl_rightrec;
 260#ifdef __KERNEL__
 261        spinlock_t      pagb_lock;      /* lock for pagb_tree */
 262        struct rb_root  pagb_tree;      /* ordered tree of busy extents */
 263
 264        atomic_t        pagf_fstrms;    /* # of filestreams active in this AG */
 265
 266        spinlock_t      pag_ici_lock;   /* incore inode cache lock */
 267        struct radix_tree_root pag_ici_root;    /* incore inode cache root */
 268        int             pag_ici_reclaimable;    /* reclaimable inodes */
 269        struct mutex    pag_ici_reclaim_lock;   /* serialisation point */
 270        unsigned long   pag_ici_reclaim_cursor; /* reclaim restart point */
 271
 272        /* buffer cache index */
 273        spinlock_t      pag_buf_lock;   /* lock for pag_buf_tree */
 274        struct rb_root  pag_buf_tree;   /* ordered tree of active buffers */
 275
 276        /* for rcu-safe freeing */
 277        struct rcu_head rcu_head;
 278#endif
 279        int             pagb_count;     /* pagb slots in use */
 280} xfs_perag_t;
 281
 282/*
 283 * tags for inode radix tree
 284 */
 285#define XFS_ICI_NO_TAG          (-1)    /* special flag for an untagged lookup
 286                                           in xfs_inode_ag_iterator */
 287#define XFS_ICI_RECLAIM_TAG     0       /* inode is to be reclaimed */
 288#define XFS_ICI_EOFBLOCKS_TAG   1       /* inode has blocks beyond EOF */
 289
 290#define XFS_AG_MAXLEVELS(mp)            ((mp)->m_ag_maxlevels)
 291#define XFS_MIN_FREELIST_RAW(bl,cl,mp)  \
 292        (MIN(bl + 1, XFS_AG_MAXLEVELS(mp)) + MIN(cl + 1, XFS_AG_MAXLEVELS(mp)))
 293#define XFS_MIN_FREELIST(a,mp)          \
 294        (XFS_MIN_FREELIST_RAW(          \
 295                be32_to_cpu((a)->agf_levels[XFS_BTNUM_BNOi]), \
 296                be32_to_cpu((a)->agf_levels[XFS_BTNUM_CNTi]), mp))
 297#define XFS_MIN_FREELIST_PAG(pag,mp)    \
 298        (XFS_MIN_FREELIST_RAW(          \
 299                (unsigned int)(pag)->pagf_levels[XFS_BTNUM_BNOi], \
 300                (unsigned int)(pag)->pagf_levels[XFS_BTNUM_CNTi], mp))
 301
 302#define XFS_AGB_TO_FSB(mp,agno,agbno)   \
 303        (((xfs_fsblock_t)(agno) << (mp)->m_sb.sb_agblklog) | (agbno))
 304#define XFS_FSB_TO_AGNO(mp,fsbno)       \
 305        ((xfs_agnumber_t)((fsbno) >> (mp)->m_sb.sb_agblklog))
 306#define XFS_FSB_TO_AGBNO(mp,fsbno)      \
 307        ((xfs_agblock_t)((fsbno) & xfs_mask32lo((mp)->m_sb.sb_agblklog)))
 308#define XFS_AGB_TO_DADDR(mp,agno,agbno) \
 309        ((xfs_daddr_t)XFS_FSB_TO_BB(mp, \
 310                (xfs_fsblock_t)(agno) * (mp)->m_sb.sb_agblocks + (agbno)))
 311#define XFS_AG_DADDR(mp,agno,d)         (XFS_AGB_TO_DADDR(mp, agno, 0) + (d))
 312
 313/*
 314 * For checking for bad ranges of xfs_daddr_t's, covering multiple
 315 * allocation groups or a single xfs_daddr_t that's a superblock copy.
 316 */
 317#define XFS_AG_CHECK_DADDR(mp,d,len)    \
 318        ((len) == 1 ? \
 319            ASSERT((d) == XFS_SB_DADDR || \
 320                   xfs_daddr_to_agbno(mp, d) != XFS_SB_DADDR) : \
 321            ASSERT(xfs_daddr_to_agno(mp, d) == \
 322                   xfs_daddr_to_agno(mp, (d) + (len) - 1)))
 323
 324#endif  /* __XFS_AG_H__ */
 325
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