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 /*
  41  * Flags for xfs_alloc_fix_freelist.
  42  */
  43 #define XFS_ALLOC_FLAG_TRYLOCK  0x00000001  /* use trylock for buffer locking */
  44 #define XFS_ALLOC_FLAG_FREEING  0x00000002  /* indicate caller is freeing extents*/
  45
  46 /*
  47  * In order to avoid ENOSPC-related deadlock caused by
  48  * out-of-order locking of AGF buffer (PV 947395), we place
  49  * constraints on the relationship among actual allocations for
  50  * data blocks, freelist blocks, and potential file data bmap
  51  * btree blocks. However, these restrictions may result in no
  52  * actual space allocated for a delayed extent, for example, a data
  53  * block in a certain AG is allocated but there is no additional
  54  * block for the additional bmap btree block due to a split of the
  55  * bmap btree of the file. The result of this may lead to an
  56  * infinite loop in xfssyncd when the file gets flushed to disk and
  57  * all delayed extents need to be actually allocated. To get around
  58  * this, we explicitly set aside a few blocks which will not be
  59  * reserved in delayed allocation. Considering the minimum number of
  60  * needed freelist blocks is 4 fsbs _per AG_, a potential split of file's bmap
  61  * btree requires 1 fsb, so we set the number of set-aside blocks
  62  * to 4 + 4*agcount.
  63  */
  64 #define XFS_ALLOC_SET_ASIDE(mp)  (4 + ((mp)->m_sb.sb_agcount * 4))
  65
  66 /*
  67  * Argument structure for xfs_alloc routines.
  68  * This is turned into a structure to avoid having 20 arguments passed
  69  * down several levels of the stack.
  70  */
  71 typedef struct xfs_alloc_arg {
  72         struct xfs_trans *tp;           /* transaction pointer */
  73         struct xfs_mount *mp;           /* file system mount point */
  74         struct xfs_buf  *agbp;          /* buffer for a.g. freelist header */
  75         struct xfs_perag *pag;          /* per-ag struct for this agno */
  76         xfs_fsblock_t   fsbno;          /* file system block number */
  77         xfs_agnumber_t  agno;           /* allocation group number */
  78         xfs_agblock_t   agbno;          /* allocation group-relative block # */
  79         xfs_extlen_t    minlen;         /* minimum size of extent */
  80         xfs_extlen_t    maxlen;         /* maximum size of extent */
  81         xfs_extlen_t    mod;            /* mod value for extent size */
  82         xfs_extlen_t    prod;           /* prod value for extent size */
  83         xfs_extlen_t    minleft;        /* min blocks must be left after us */
  84         xfs_extlen_t    total;          /* total blocks needed in xaction */
  85         xfs_extlen_t    alignment;      /* align answer to multiple of this */
  86         xfs_extlen_t    minalignslop;   /* slop for minlen+alignment calcs */
  87         xfs_extlen_t    len;            /* output: actual size of extent */
  88         xfs_alloctype_t type;           /* allocation type XFS_ALLOCTYPE_... */
  89         xfs_alloctype_t otype;          /* original allocation type */
  90         char            wasdel;         /* set if allocation was prev delayed */
  91         char            wasfromfl;      /* set if allocation is from freelist */
  92         char            isfl;           /* set if is freelist blocks - !acctg */
  93         char            userdata;       /* set if this is user data */
  94         xfs_fsblock_t   firstblock;     /* io first block allocated */
  95 } xfs_alloc_arg_t;
  96
  97 /*
  98  * Defines for userdata
  99  */
 100 #define XFS_ALLOC_USERDATA              1       /* allocation is for user data*/
 101 #define XFS_ALLOC_INITIAL_USER_DATA     2       /* special case start of file */
 102
 103 /*
 104  * Find the length of the longest extent in an AG.
 105  */
 106 xfs_extlen_t
 107 xfs_alloc_longest_free_extent(struct xfs_mount *mp,
 108                 struct xfs_perag *pag);
 109
 110 #ifdef __KERNEL__
 111
 112 #if defined(XFS_ALLOC_TRACE)
 113 /*
 114  * Allocation tracing buffer size.
 115  */
 116 #define XFS_ALLOC_TRACE_SIZE    4096
 117 extern ktrace_t *xfs_alloc_trace_buf;
 118
 119 /*
 120  * Types for alloc tracing.
 121  */
 122 #define XFS_ALLOC_KTRACE_ALLOC  1
 123 #define XFS_ALLOC_KTRACE_FREE   2
 124 #define XFS_ALLOC_KTRACE_MODAGF 3
 125 #define XFS_ALLOC_KTRACE_BUSY   4
 126 #define XFS_ALLOC_KTRACE_UNBUSY 5
 127 #define XFS_ALLOC_KTRACE_BUSYSEARCH     6
 128 #endif
 129
 130 void
 131 xfs_alloc_mark_busy(xfs_trans_t *tp,
 132                 xfs_agnumber_t agno,
 133                 xfs_agblock_t bno,
 134                 xfs_extlen_t len);
 135
 136 void
 137 xfs_alloc_clear_busy(xfs_trans_t *tp,
 138                 xfs_agnumber_t ag,
 139                 int idx);
 140
 141 #endif  /* __KERNEL__ */
 142
 143 /*
 144  * Compute and fill in value of m_ag_maxlevels.
 145  */
 146 void
 147 xfs_alloc_compute_maxlevels(
 148         struct xfs_mount        *mp);   /* file system mount structure */
 149
 150 /*
 151  * Get a block from the freelist.
 152  * Returns with the buffer for the block gotten.
 153  */
 154 int                             /* error */
 155 xfs_alloc_get_freelist(
 156         struct xfs_trans *tp,   /* transaction pointer */
 157         struct xfs_buf  *agbp,  /* buffer containing the agf structure */
 158         xfs_agblock_t   *bnop,  /* block address retrieved from freelist */
 159         int             btreeblk); /* destination is a AGF btree */
 160
 161 /*
 162  * Log the given fields from the agf structure.
 163  */
 164 void
 165 xfs_alloc_log_agf(
 166         struct xfs_trans *tp,   /* transaction pointer */
 167         struct xfs_buf  *bp,    /* buffer for a.g. freelist header */
 168         int             fields);/* mask of fields to be logged (XFS_AGF_...) */
 169
 170 /*
 171  * Interface for inode allocation to force the pag data to be initialized.
 172  */
 173 int                             /* error */
 174 xfs_alloc_pagf_init(
 175         struct xfs_mount *mp,   /* file system mount structure */
 176         struct xfs_trans *tp,   /* transaction pointer */
 177         xfs_agnumber_t  agno,   /* allocation group number */
 178         int             flags); /* XFS_ALLOC_FLAGS_... */
 179
 180 /*
 181  * Put the block on the freelist for the allocation group.
 182  */
 183 int                             /* error */
 184 xfs_alloc_put_freelist(
 185         struct xfs_trans *tp,   /* transaction pointer */
 186         struct xfs_buf  *agbp,  /* buffer for a.g. freelist header */
 187         struct xfs_buf  *agflbp,/* buffer for a.g. free block array */
 188         xfs_agblock_t   bno,    /* block being freed */
 189         int             btreeblk); /* owner was a AGF btree */
 190
 191 /*
 192  * Read in the allocation group header (free/alloc section).
 193  */
 194 int                                     /* error  */
 195 xfs_alloc_read_agf(
 196         struct xfs_mount *mp,           /* mount point structure */
 197         struct xfs_trans *tp,           /* transaction pointer */
 198         xfs_agnumber_t  agno,           /* allocation group number */
 199         int             flags,          /* XFS_ALLOC_FLAG_... */
 200         struct xfs_buf  **bpp);         /* buffer for the ag freelist header */
 201
 202 /*
 203  * Allocate an extent (variable-size).
 204  */
 205 int                             /* error */
 206 xfs_alloc_vextent(
 207         xfs_alloc_arg_t *args); /* allocation argument structure */
 208
 209 /*
 210  * Free an extent.
 211  */
 212 int                             /* error */
 213 xfs_free_extent(
 214         struct xfs_trans *tp,   /* transaction pointer */
 215         xfs_fsblock_t   bno,    /* starting block number of extent */
 216         xfs_extlen_t    len);   /* length of extent */
 217
 218 #endif  /* __XFS_ALLOC_H__ */