release/src-rt-6.x.4708/linux/linux-2.6.36/fs/xfs/xfs_ag.h

   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
  27 struct xfs_buf;
  28 struct xfs_mount;
  29 struct 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
  51 typedef 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 *)XFS_BUF_PTR(bp))
 107
 108 extern 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
 116 typedef 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 *)XFS_BUF_PTR(bp))
 160
 161 extern 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 *)XFS_BUF_PTR(bp))
 172
 173 typedef struct xfs_agfl {
 174         __be32          agfl_bno[1];    /* actually XFS_AGFL_SIZE(mp) */
 175 } xfs_agfl_t;
 176
 177 /*
 178  * Busy block/extent entry.  Indexed by a rbtree in perag to mark blocks that
 179  * have been freed but whose transactions aren't committed to disk yet.
 180  *
 181  * Note that we use the transaction ID to record the transaction, not the
 182  * transaction structure itself. See xfs_alloc_busy_insert() for details.
 183  */
 184 struct xfs_busy_extent {
 185         struct rb_node  rb_node;        /* ag by-bno indexed search tree */
 186         struct list_head list;          /* transaction busy extent list */
 187         xfs_agnumber_t  agno;
 188         xfs_agblock_t   bno;
 189         xfs_extlen_t    length;
 190         xlog_tid_t      tid;            /* transaction that created this */
 191 };
 192
 193 /*
 194  * Per-ag incore structure, copies of information in agf and agi,
 195  * to improve the performance of allocation group selection.
 196  */
 197 #define XFS_PAGB_NUM_SLOTS      128
 198
 199 typedef struct xfs_perag {
 200         struct xfs_mount *pag_mount;    /* owner filesystem */
 201         xfs_agnumber_t  pag_agno;       /* AG this structure belongs to */
 202         atomic_t        pag_ref;        /* perag reference count */
 203         char            pagf_init;      /* this agf's entry is initialized */
 204         char            pagi_init;      /* this agi's entry is initialized */
 205         char            pagf_metadata;  /* the agf is preferred to be metadata */
 206         char            pagi_inodeok;   /* The agi is ok for inodes */
 207         __uint8_t       pagf_levels[XFS_BTNUM_AGF];
 208                                         /* # of levels in bno & cnt btree */
 209         __uint32_t      pagf_flcount;   /* count of blocks in freelist */
 210         xfs_extlen_t    pagf_freeblks;  /* total free blocks */
 211         xfs_extlen_t    pagf_longest;   /* longest free space */
 212         __uint32_t      pagf_btreeblks; /* # of blocks held in AGF btrees */
 213         xfs_agino_t     pagi_freecount; /* number of free inodes */
 214         xfs_agino_t     pagi_count;     /* number of allocated inodes */
 215
 216         /*
 217          * Inode allocation search lookup optimisation.
 218          * If the pagino matches, the search for new inodes
 219          * doesn't need to search the near ones again straight away
 220          */
 221         xfs_agino_t     pagl_pagino;
 222         xfs_agino_t     pagl_leftrec;
 223         xfs_agino_t     pagl_rightrec;
 224 #ifdef __KERNEL__
 225         spinlock_t      pagb_lock;      /* lock for pagb_tree */
 226         struct rb_root  pagb_tree;      /* ordered tree of busy extents */
 227
 228         atomic_t        pagf_fstrms;    /* # of filestreams active in this AG */
 229
 230         rwlock_t        pag_ici_lock;   /* incore inode lock */
 231         struct radix_tree_root pag_ici_root;    /* incore inode cache root */
 232         int             pag_ici_reclaimable;    /* reclaimable inodes */
 233 #endif
 234         int             pagb_count;     /* pagb slots in use */
 235 } xfs_perag_t;
 236
 237 /*
 238  * tags for inode radix tree
 239  */
 240 #define XFS_ICI_NO_TAG          (-1)    /* special flag for an untagged lookup
 241                                            in xfs_inode_ag_iterator */
 242 #define XFS_ICI_RECLAIM_TAG     0       /* inode is to be reclaimed */
 243
 244 #define XFS_AG_MAXLEVELS(mp)            ((mp)->m_ag_maxlevels)
 245 #define XFS_MIN_FREELIST_RAW(bl,cl,mp)  \
 246         (MIN(bl + 1, XFS_AG_MAXLEVELS(mp)) + MIN(cl + 1, XFS_AG_MAXLEVELS(mp)))
 247 #define XFS_MIN_FREELIST(a,mp)          \
 248         (XFS_MIN_FREELIST_RAW(          \
 249                 be32_to_cpu((a)->agf_levels[XFS_BTNUM_BNOi]), \
 250                 be32_to_cpu((a)->agf_levels[XFS_BTNUM_CNTi]), mp))
 251 #define XFS_MIN_FREELIST_PAG(pag,mp)    \
 252         (XFS_MIN_FREELIST_RAW(          \
 253                 (unsigned int)(pag)->pagf_levels[XFS_BTNUM_BNOi], \
 254                 (unsigned int)(pag)->pagf_levels[XFS_BTNUM_CNTi], mp))
 255
 256 #define XFS_AGB_TO_FSB(mp,agno,agbno)   \
 257         (((xfs_fsblock_t)(agno) << (mp)->m_sb.sb_agblklog) | (agbno))
 258 #define XFS_FSB_TO_AGNO(mp,fsbno)       \
 259         ((xfs_agnumber_t)((fsbno) >> (mp)->m_sb.sb_agblklog))
 260 #define XFS_FSB_TO_AGBNO(mp,fsbno)      \
 261         ((xfs_agblock_t)((fsbno) & xfs_mask32lo((mp)->m_sb.sb_agblklog)))
 262 #define XFS_AGB_TO_DADDR(mp,agno,agbno) \
 263         ((xfs_daddr_t)XFS_FSB_TO_BB(mp, \
 264                 (xfs_fsblock_t)(agno) * (mp)->m_sb.sb_agblocks + (agbno)))
 265 #define XFS_AG_DADDR(mp,agno,d)         (XFS_AGB_TO_DADDR(mp, agno, 0) + (d))
 266
 267 /*
 268  * For checking for bad ranges of xfs_daddr_t's, covering multiple
 269  * allocation groups or a single xfs_daddr_t that's a superblock copy.
 270  */
 271 #define XFS_AG_CHECK_DADDR(mp,d,len)    \
 272         ((len) == 1 ? \
 273             ASSERT((d) == XFS_SB_DADDR || \
 274                    xfs_daddr_to_agbno(mp, d) != XFS_SB_DADDR) : \
 275             ASSERT(xfs_daddr_to_agno(mp, d) == \
 276                    xfs_daddr_to_agno(mp, (d) + (len) - 1)))
 277
 278 #endif  /* __XFS_AG_H__ */