fs/xfs/xfs_bmap.h

   1 /*
   2  * Copyright (c) 2000-2006 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_BMAP_H__
  19 #define __XFS_BMAP_H__
  20
  21 struct getbmap;
  22 struct xfs_bmbt_irec;
  23 struct xfs_ifork;
  24 struct xfs_inode;
  25 struct xfs_mount;
  26 struct xfs_trans;
  27
  28 extern kmem_zone_t      *xfs_bmap_free_item_zone;
  29
  30 /*
  31  * DELTA: describe a change to the in-core extent list.
  32  *
  33  * Internally the use of xed_blockount is somewhat funky.
  34  * xed_blockcount contains an offset much of the time because this
  35  * makes merging changes easier.  (xfs_fileoff_t and xfs_filblks_t are
  36  * the same underlying type).
  37  */
  38 typedef struct xfs_extdelta
  39 {
  40         xfs_fileoff_t           xed_startoff;   /* offset of range */
  41         xfs_filblks_t           xed_blockcount; /* blocks in range */
  42 } xfs_extdelta_t;
  43
  44 /*
  45  * List of extents to be free "later".
  46  * The list is kept sorted on xbf_startblock.
  47  */
  48 typedef struct xfs_bmap_free_item
  49 {
  50         xfs_fsblock_t           xbfi_startblock;/* starting fs block number */
  51         xfs_extlen_t            xbfi_blockcount;/* number of blocks in extent */
  52         struct xfs_bmap_free_item *xbfi_next;   /* link to next entry */
  53 } xfs_bmap_free_item_t;
  54
  55 /*
  56  * Header for free extent list.
  57  */
  58 typedef struct xfs_bmap_free
  59 {
  60         xfs_bmap_free_item_t    *xbf_first;     /* list of to-be-free extents */
  61         int                     xbf_count;      /* count of items on list */
  62         int                     xbf_low;        /* kludge: alloc in low mode */
  63 } xfs_bmap_free_t;
  64
  65 #define XFS_BMAP_MAX_NMAP       4
  66
  67 /*
  68  * Flags for xfs_bmapi
  69  */
  70 #define XFS_BMAPI_WRITE         0x001   /* write operation: allocate space */
  71 #define XFS_BMAPI_DELAY         0x002   /* delayed write operation */
  72 #define XFS_BMAPI_ENTIRE        0x004   /* return entire extent, not trimmed */
  73 #define XFS_BMAPI_METADATA      0x008   /* mapping metadata not user data */
  74 #define XFS_BMAPI_EXACT         0x010   /* allocate only to spec'd bounds */
  75 #define XFS_BMAPI_ATTRFORK      0x020   /* use attribute fork not data */
  76 #define XFS_BMAPI_ASYNC         0x040   /* bunmapi xactions can be async */
  77 #define XFS_BMAPI_RSVBLOCKS     0x080   /* OK to alloc. reserved data blocks */
  78 #define XFS_BMAPI_PREALLOC      0x100   /* preallocation op: unwritten space */
  79 #define XFS_BMAPI_IGSTATE       0x200   /* Ignore state - */
  80                                         /* combine contig. space */
  81 #define XFS_BMAPI_CONTIG        0x400   /* must allocate only one extent */
  82 /*      XFS_BMAPI_DIRECT_IO     0x800   */
  83 #define XFS_BMAPI_CONVERT       0x1000  /* unwritten extent conversion - */
  84                                         /* need write cache flushing and no */
  85                                         /* additional allocation alignments */
  86
  87 #define XFS_BMAPI_AFLAG(w)      xfs_bmapi_aflag(w)
  88 static inline int xfs_bmapi_aflag(int w)
  89 {
  90         return (w == XFS_ATTR_FORK ? XFS_BMAPI_ATTRFORK : 0);
  91 }
  92
  93 /*
  94  * Special values for xfs_bmbt_irec_t br_startblock field.
  95  */
  96 #define DELAYSTARTBLOCK         ((xfs_fsblock_t)-1LL)
  97 #define HOLESTARTBLOCK          ((xfs_fsblock_t)-2LL)
  98
  99 #define XFS_BMAP_INIT(flp,fbp)  xfs_bmap_init(flp,fbp)
 100 static inline void xfs_bmap_init(xfs_bmap_free_t *flp, xfs_fsblock_t *fbp)
 101 {
 102         ((flp)->xbf_first = NULL, (flp)->xbf_count = 0, \
 103                 (flp)->xbf_low = 0, *(fbp) = NULLFSBLOCK);
 104 }
 105
 106 /*
 107  * Argument structure for xfs_bmap_alloc.
 108  */
 109 typedef struct xfs_bmalloca {
 110         xfs_fsblock_t           firstblock; /* i/o first block allocated */
 111         xfs_fsblock_t           rval;   /* starting block of new extent */
 112         xfs_fileoff_t           off;    /* offset in file filling in */
 113         struct xfs_trans        *tp;    /* transaction pointer */
 114         struct xfs_inode        *ip;    /* incore inode pointer */
 115         struct xfs_bmbt_irec    *prevp; /* extent before the new one */
 116         struct xfs_bmbt_irec    *gotp;  /* extent after, or delayed */
 117         xfs_extlen_t            alen;   /* i/o length asked/allocated */
 118         xfs_extlen_t            total;  /* total blocks needed for xaction */
 119         xfs_extlen_t            minlen; /* mininum allocation size (blocks) */
 120         xfs_extlen_t            minleft; /* amount must be left after alloc */
 121         char                    eof;    /* set if allocating past last extent */
 122         char                    wasdel; /* replacing a delayed allocation */
 123         char                    userdata;/* set if is user data */
 124         char                    low;    /* low on space, using seq'l ags */
 125         char                    aeof;   /* allocated space at eof */
 126         char                    conv;   /* overwriting unwritten extents */
 127 } xfs_bmalloca_t;
 128
 129 #ifdef __KERNEL__
 130
 131 #if defined(XFS_BMAP_TRACE)
 132 /*
 133  * Trace operations for bmap extent tracing
 134  */
 135 #define XFS_BMAP_KTRACE_DELETE  1
 136 #define XFS_BMAP_KTRACE_INSERT  2
 137 #define XFS_BMAP_KTRACE_PRE_UP  3
 138 #define XFS_BMAP_KTRACE_POST_UP 4
 139
 140 #define XFS_BMAP_TRACE_SIZE     4096    /* size of global trace buffer */
 141 #define XFS_BMAP_KTRACE_SIZE    32      /* size of per-inode trace buffer */
 142 extern ktrace_t *xfs_bmap_trace_buf;
 143
 144 /*
 145  * Add bmap trace insert entries for all the contents of the extent list.
 146  */
 147 void
 148 xfs_bmap_trace_exlist(
 149         const char              *fname,         /* function name */
 150         struct xfs_inode        *ip,            /* incore inode pointer */
 151         xfs_extnum_t            cnt,            /* count of entries in list */
 152         int                     whichfork);     /* data or attr fork */
 153 #define XFS_BMAP_TRACE_EXLIST(ip,c,w)   \
 154         xfs_bmap_trace_exlist(__FUNCTION__,ip,c,w)
 155 #else
 156 #define XFS_BMAP_TRACE_EXLIST(ip,c,w)
 157 #endif
 158
 159 /*
 160  * Convert inode from non-attributed to attributed.
 161  * Must not be in a transaction, ip must not be locked.
 162  */
 163 int                                     /* error code */
 164 xfs_bmap_add_attrfork(
 165         struct xfs_inode        *ip,    /* incore inode pointer */
 166         int                     size,   /* space needed for new attribute */
 167         int                     rsvd);  /* flag for reserved block allocation */
 168
 169 /*
 170  * Add the extent to the list of extents to be free at transaction end.
 171  * The list is maintained sorted (by block number).
 172  */
 173 void
 174 xfs_bmap_add_free(
 175         xfs_fsblock_t           bno,            /* fs block number of extent */
 176         xfs_filblks_t           len,            /* length of extent */
 177         xfs_bmap_free_t         *flist,         /* list of extents */
 178         struct xfs_mount        *mp);           /* mount point structure */
 179
 180 /*
 181  * Routine to clean up the free list data structure when
 182  * an error occurs during a transaction.
 183  */
 184 void
 185 xfs_bmap_cancel(
 186         xfs_bmap_free_t         *flist);        /* free list to clean up */
 187
 188 /*
 189  * Compute and fill in the value of the maximum depth of a bmap btree
 190  * in this filesystem.  Done once, during mount.
 191  */
 192 void
 193 xfs_bmap_compute_maxlevels(
 194         struct xfs_mount        *mp,    /* file system mount structure */
 195         int                     whichfork);     /* data or attr fork */
 196
 197 /*
 198  * Routine to be called at transaction's end by xfs_bmapi, xfs_bunmapi
 199  * caller.  Frees all the extents that need freeing, which must be done
 200  * last due to locking considerations.
 201  *
 202  * Return 1 if the given transaction was committed and a new one allocated,
 203  * and 0 otherwise.
 204  */
 205 int                                             /* error */
 206 xfs_bmap_finish(
 207         struct xfs_trans        **tp,           /* transaction pointer addr */
 208         xfs_bmap_free_t         *flist,         /* i/o: list extents to free */
 209         int                     *committed);    /* xact committed or not */
 210
 211 /*
 212  * Returns the file-relative block number of the first unused block in the file.
 213  * This is the lowest-address hole if the file has holes, else the first block
 214  * past the end of file.
 215  */
 216 int                                             /* error */
 217 xfs_bmap_first_unused(
 218         struct xfs_trans        *tp,            /* transaction pointer */
 219         struct xfs_inode        *ip,            /* incore inode */
 220         xfs_extlen_t            len,            /* size of hole to find */
 221         xfs_fileoff_t           *unused,        /* unused block num */
 222         int                     whichfork);     /* data or attr fork */
 223
 224 /*
 225  * Returns the file-relative block number of the last block + 1 before
 226  * last_block (input value) in the file.
 227  * This is not based on i_size, it is based on the extent list.
 228  * Returns 0 for local files, as they do not have an extent list.
 229  */
 230 int                                             /* error */
 231 xfs_bmap_last_before(
 232         struct xfs_trans        *tp,            /* transaction pointer */
 233         struct xfs_inode        *ip,            /* incore inode */
 234         xfs_fileoff_t           *last_block,    /* last block */
 235         int                     whichfork);     /* data or attr fork */
 236
 237 /*
 238  * Returns the file-relative block number of the first block past eof in
 239  * the file.  This is not based on i_size, it is based on the extent list.
 240  * Returns 0 for local files, as they do not have an extent list.
 241  */
 242 int                                             /* error */
 243 xfs_bmap_last_offset(
 244         struct xfs_trans        *tp,            /* transaction pointer */
 245         struct xfs_inode        *ip,            /* incore inode */
 246         xfs_fileoff_t           *unused,        /* last block num */
 247         int                     whichfork);     /* data or attr fork */
 248
 249 /*
 250  * Returns whether the selected fork of the inode has exactly one
 251  * block or not.  For the data fork we check this matches di_size,
 252  * implying the file's range is 0..bsize-1.
 253  */
 254 int
 255 xfs_bmap_one_block(
 256         struct xfs_inode        *ip,            /* incore inode */
 257         int                     whichfork);     /* data or attr fork */
 258
 259 /*
 260  * Read in the extents to iu_extents.
 261  * All inode fields are set up by caller, we just traverse the btree
 262  * and copy the records in.
 263  */
 264 int                                             /* error */
 265 xfs_bmap_read_extents(
 266         struct xfs_trans        *tp,            /* transaction pointer */
 267         struct xfs_inode        *ip,            /* incore inode */
 268         int                     whichfork);     /* data or attr fork */
 269
 270 /*
 271  * Map file blocks to filesystem blocks.
 272  * File range is given by the bno/len pair.
 273  * Adds blocks to file if a write ("flags & XFS_BMAPI_WRITE" set)
 274  * into a hole or past eof.
 275  * Only allocates blocks from a single allocation group,
 276  * to avoid locking problems.
 277  * The returned value in "firstblock" from the first call in a transaction
 278  * must be remembered and presented to subsequent calls in "firstblock".
 279  * An upper bound for the number of blocks to be allocated is supplied to
 280  * the first call in "total"; if no allocation group has that many free
 281  * blocks then the call will fail (return NULLFSBLOCK in "firstblock").
 282  */
 283 int                                             /* error */
 284 xfs_bmapi(
 285         struct xfs_trans        *tp,            /* transaction pointer */
 286         struct xfs_inode        *ip,            /* incore inode */
 287         xfs_fileoff_t           bno,            /* starting file offs. mapped */
 288         xfs_filblks_t           len,            /* length to map in file */
 289         int                     flags,          /* XFS_BMAPI_... */
 290         xfs_fsblock_t           *firstblock,    /* first allocated block
 291                                                    controls a.g. for allocs */
 292         xfs_extlen_t            total,          /* total blocks needed */
 293         struct xfs_bmbt_irec    *mval,          /* output: map values */
 294         int                     *nmap,          /* i/o: mval size/count */
 295         xfs_bmap_free_t         *flist,         /* i/o: list extents to free */
 296         xfs_extdelta_t          *delta);        /* o: change made to incore
 297                                                    extents */
 298
 299 /*
 300  * Map file blocks to filesystem blocks, simple version.
 301  * One block only, read-only.
 302  * For flags, only the XFS_BMAPI_ATTRFORK flag is examined.
 303  * For the other flag values, the effect is as if XFS_BMAPI_METADATA
 304  * was set and all the others were clear.
 305  */
 306 int                                             /* error */
 307 xfs_bmapi_single(
 308         struct xfs_trans        *tp,            /* transaction pointer */
 309         struct xfs_inode        *ip,            /* incore inode */
 310         int                     whichfork,      /* data or attr fork */
 311         xfs_fsblock_t           *fsb,           /* output: mapped block */
 312         xfs_fileoff_t           bno);           /* starting file offs. mapped */
 313
 314 /*
 315  * Unmap (remove) blocks from a file.
 316  * If nexts is nonzero then the number of extents to remove is limited to
 317  * that value.  If not all extents in the block range can be removed then
 318  * *done is set.
 319  */
 320 int                                             /* error */
 321 xfs_bunmapi(
 322         struct xfs_trans        *tp,            /* transaction pointer */
 323         struct xfs_inode        *ip,            /* incore inode */
 324         xfs_fileoff_t           bno,            /* starting offset to unmap */
 325         xfs_filblks_t           len,            /* length to unmap in file */
 326         int                     flags,          /* XFS_BMAPI_... */
 327         xfs_extnum_t            nexts,          /* number of extents max */
 328         xfs_fsblock_t           *firstblock,    /* first allocated block
 329                                                    controls a.g. for allocs */
 330         xfs_bmap_free_t         *flist,         /* i/o: list extents to free */
 331         xfs_extdelta_t          *delta,         /* o: change made to incore
 332                                                    extents */
 333         int                     *done);         /* set if not done yet */
 334
 335 /*
 336  * Fcntl interface to xfs_bmapi.
 337  */
 338 int                                             /* error code */
 339 xfs_getbmap(
 340         xfs_inode_t             *ip,
 341         struct getbmap          *bmv,           /* user bmap structure */
 342         void                    __user *ap,     /* pointer to user's array */
 343         int                     iflags);        /* interface flags */
 344
 345 /*
 346  * Check if the endoff is outside the last extent. If so the caller will grow
 347  * the allocation to a stripe unit boundary
 348  */
 349 int
 350 xfs_bmap_eof(
 351         struct xfs_inode        *ip,
 352         xfs_fileoff_t           endoff,
 353         int                     whichfork,
 354         int                     *eof);
 355
 356 /*
 357  * Count fsblocks of the given fork.
 358  */
 359 int
 360 xfs_bmap_count_blocks(
 361         xfs_trans_t             *tp,
 362         struct xfs_inode        *ip,
 363         int                     whichfork,
 364         int                     *count);
 365
 366 /*
 367  * Check an extent list, which has just been read, for
 368  * any bit in the extent flag field.
 369  */
 370 int
 371 xfs_check_nostate_extents(
 372         struct xfs_ifork        *ifp,
 373         xfs_extnum_t            idx,
 374         xfs_extnum_t            num);
 375
 376 /*
 377  * Search the extent records for the entry containing block bno.
 378  * If bno lies in a hole, point to the next entry.  If bno lies
 379  * past eof, *eofp will be set, and *prevp will contain the last
 380  * entry (null if none).  Else, *lastxp will be set to the index
 381  * of the found entry; *gotp will contain the entry.
 382  */
 383 xfs_bmbt_rec_host_t *
 384 xfs_bmap_search_multi_extents(struct xfs_ifork *, xfs_fileoff_t, int *,
 385                         xfs_extnum_t *, xfs_bmbt_irec_t *, xfs_bmbt_irec_t *);
 386
 387 #endif  /* __KERNEL__ */
 388
 389 #endif  /* __XFS_BMAP_H__ */