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