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

   1 /*
   2  * Copyright (c) 2000-2002,2005 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_ALLOC_H__
  19 #define __XFS_ALLOC_H__
  20
  21 struct xfs_buf;
  22 struct xfs_mount;
  23 struct xfs_perag;
  24 struct xfs_trans;
  25 struct xfs_busy_extent;
  26
  27 /*
  28  * Freespace allocation types.  Argument to xfs_alloc_[v]extent.
  29  */
  30 #define XFS_ALLOCTYPE_ANY_AG    0x01    /* allocate anywhere, use rotor */
  31 #define XFS_ALLOCTYPE_FIRST_AG  0x02    /* ... start at ag 0 */
  32 #define XFS_ALLOCTYPE_START_AG  0x04    /* anywhere, start in this a.g. */
  33 #define XFS_ALLOCTYPE_THIS_AG   0x08    /* anywhere in this a.g. */
  34 #define XFS_ALLOCTYPE_START_BNO 0x10    /* near this block else anywhere */
  35 #define XFS_ALLOCTYPE_NEAR_BNO  0x20    /* in this a.g. and near this block */
  36 #define XFS_ALLOCTYPE_THIS_BNO  0x40    /* at exactly this block */
  37
  38 /* this should become an enum again when the tracing code is fixed */
  39 typedef unsigned int xfs_alloctype_t;
  40
  41 #define XFS_ALLOC_TYPES \
  42         { XFS_ALLOCTYPE_ANY_AG,         "ANY_AG" }, \
  43         { XFS_ALLOCTYPE_FIRST_AG,       "FIRST_AG" }, \
  44         { XFS_ALLOCTYPE_START_AG,       "START_AG" }, \
  45         { XFS_ALLOCTYPE_THIS_AG,        "THIS_AG" }, \
  46         { XFS_ALLOCTYPE_START_BNO,      "START_BNO" }, \
  47         { XFS_ALLOCTYPE_NEAR_BNO,       "NEAR_BNO" }, \
  48         { XFS_ALLOCTYPE_THIS_BNO,       "THIS_BNO" }
  49
  50 /*
  51  * Flags for xfs_alloc_fix_freelist.
  52  */
  53 #define XFS_ALLOC_FLAG_TRYLOCK  0x00000001  /* use trylock for buffer locking */
  54 #define XFS_ALLOC_FLAG_FREEING  0x00000002  /* indicate caller is freeing extents*/
  55
  56 /*
  57  * In order to avoid ENOSPC-related deadlock caused by
  58  * out-of-order locking of AGF buffer (PV 947395), we place
  59  * constraints on the relationship among actual allocations for
  60  * data blocks, freelist blocks, and potential file data bmap
  61  * btree blocks. However, these restrictions may result in no
  62  * actual space allocated for a delayed extent, for example, a data
  63  * block in a certain AG is allocated but there is no additional
  64  * block for the additional bmap btree block due to a split of the
  65  * bmap btree of the file. The result of this may lead to an
  66  * infinite loop in xfssyncd when the file gets flushed to disk and
  67  * all delayed extents need to be actually allocated. To get around
  68  * this, we explicitly set aside a few blocks which will not be
  69  * reserved in delayed allocation. Considering the minimum number of
  70  * needed freelist blocks is 4 fsbs _per AG_, a potential split of file's bmap
  71  * btree requires 1 fsb, so we set the number of set-aside blocks
  72  * to 4 + 4*agcount.
  73  */
  74 #define XFS_ALLOC_SET_ASIDE(mp)  (4 + ((mp)->m_sb.sb_agcount * 4))
  75
  76 /*
  77  * Argument structure for xfs_alloc routines.
  78  * This is turned into a structure to avoid having 20 arguments passed
  79  * down several levels of the stack.
  80  */
  81 typedef struct xfs_alloc_arg {
  82         struct xfs_trans *tp;           /* transaction pointer */
  83         struct xfs_mount *mp;           /* file system mount point */
  84         struct xfs_buf  *agbp;          /* buffer for a.g. freelist header */
  85         struct xfs_perag *pag;          /* per-ag struct for this agno */
  86         xfs_fsblock_t   fsbno;          /* file system block number */
  87         xfs_agnumber_t  agno;           /* allocation group number */
  88         xfs_agblock_t   agbno;          /* allocation group-relative block # */
  89         xfs_extlen_t    minlen;         /* minimum size of extent */
  90         xfs_extlen_t    maxlen;         /* maximum size of extent */
  91         xfs_extlen_t    mod;            /* mod value for extent size */
  92         xfs_extlen_t    prod;           /* prod value for extent size */
  93         xfs_extlen_t    minleft;        /* min blocks must be left after us */
  94         xfs_extlen_t    total;          /* total blocks needed in xaction */
  95         xfs_extlen_t    alignment;      /* align answer to multiple of this */
  96         xfs_extlen_t    minalignslop;   /* slop for minlen+alignment calcs */
  97         xfs_extlen_t    len;            /* output: actual size of extent */
  98         xfs_alloctype_t type;           /* allocation type XFS_ALLOCTYPE_... */
  99         xfs_alloctype_t otype;          /* original allocation type */
 100         char            wasdel;         /* set if allocation was prev delayed */
 101         char            wasfromfl;      /* set if allocation is from freelist */
 102         char            isfl;           /* set if is freelist blocks - !acctg */
 103         char            userdata;       /* set if this is user data */
 104         xfs_fsblock_t   firstblock;     /* io first block allocated */
 105 } xfs_alloc_arg_t;
 106
 107 /*
 108  * Defines for userdata
 109  */
 110 #define XFS_ALLOC_USERDATA              1       /* allocation is for user data*/
 111 #define XFS_ALLOC_INITIAL_USER_DATA     2       /* special case start of file */
 112
 113 /*
 114  * Find the length of the longest extent in an AG.
 115  */
 116 xfs_extlen_t
 117 xfs_alloc_longest_free_extent(struct xfs_mount *mp,
 118                 struct xfs_perag *pag);
 119
 120 #ifdef __KERNEL__
 121
 122 void
 123 xfs_alloc_busy_insert(xfs_trans_t *tp,
 124                 xfs_agnumber_t agno,
 125                 xfs_agblock_t bno,
 126                 xfs_extlen_t len);
 127
 128 void
 129 xfs_alloc_busy_clear(struct xfs_mount *mp, struct xfs_busy_extent *busyp);
 130
 131 #endif  /* __KERNEL__ */
 132
 133 /*
 134  * Compute and fill in value of m_ag_maxlevels.
 135  */
 136 void
 137 xfs_alloc_compute_maxlevels(
 138         struct xfs_mount        *mp);   /* file system mount structure */
 139
 140 /*
 141  * Get a block from the freelist.
 142  * Returns with the buffer for the block gotten.
 143  */
 144 int                             /* error */
 145 xfs_alloc_get_freelist(
 146         struct xfs_trans *tp,   /* transaction pointer */
 147         struct xfs_buf  *agbp,  /* buffer containing the agf structure */
 148         xfs_agblock_t   *bnop,  /* block address retrieved from freelist */
 149         int             btreeblk); /* destination is a AGF btree */
 150
 151 /*
 152  * Log the given fields from the agf structure.
 153  */
 154 void
 155 xfs_alloc_log_agf(
 156         struct xfs_trans *tp,   /* transaction pointer */
 157         struct xfs_buf  *bp,    /* buffer for a.g. freelist header */
 158         int             fields);/* mask of fields to be logged (XFS_AGF_...) */
 159
 160 /*
 161  * Interface for inode allocation to force the pag data to be initialized.
 162  */
 163 int                             /* error */
 164 xfs_alloc_pagf_init(
 165         struct xfs_mount *mp,   /* file system mount structure */
 166         struct xfs_trans *tp,   /* transaction pointer */
 167         xfs_agnumber_t  agno,   /* allocation group number */
 168         int             flags); /* XFS_ALLOC_FLAGS_... */
 169
 170 /*
 171  * Put the block on the freelist for the allocation group.
 172  */
 173 int                             /* error */
 174 xfs_alloc_put_freelist(
 175         struct xfs_trans *tp,   /* transaction pointer */
 176         struct xfs_buf  *agbp,  /* buffer for a.g. freelist header */
 177         struct xfs_buf  *agflbp,/* buffer for a.g. free block array */
 178         xfs_agblock_t   bno,    /* block being freed */
 179         int             btreeblk); /* owner was a AGF btree */
 180
 181 /*
 182  * Read in the allocation group header (free/alloc section).
 183  */
 184 int                                     /* error  */
 185 xfs_alloc_read_agf(
 186         struct xfs_mount *mp,           /* mount point structure */
 187         struct xfs_trans *tp,           /* transaction pointer */
 188         xfs_agnumber_t  agno,           /* allocation group number */
 189         int             flags,          /* XFS_ALLOC_FLAG_... */
 190         struct xfs_buf  **bpp);         /* buffer for the ag freelist header */
 191
 192 /*
 193  * Allocate an extent (variable-size).
 194  */
 195 int                             /* error */
 196 xfs_alloc_vextent(
 197         xfs_alloc_arg_t *args); /* allocation argument structure */
 198
 199 /*
 200  * Free an extent.
 201  */
 202 int                             /* error */
 203 xfs_free_extent(
 204         struct xfs_trans *tp,   /* transaction pointer */
 205         xfs_fsblock_t   bno,    /* starting block number of extent */
 206         xfs_extlen_t    len);   /* length of extent */
 207
 208 #endif  /* __XFS_ALLOC_H__ */