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  * xbf_low is used by the allocator to activate the lowspace algorithm -
  59  * when free space is running low the extent allocator may choose to
  60  * allocate an extent from an AG without leaving sufficient space for
  61  * a btree split when inserting the new extent.  In this case the allocator
  62  * will enable the lowspace algorithm which is supposed to allow further
  63  * allocations (such as btree splits and newroots) to allocate from
  64  * sequential AGs.  In order to avoid locking AGs out of order the lowspace
  65  * algorithm will start searching for free space from AG 0.  If the correct
  66  * transaction reservations have been made then this algorithm will eventually
  67  * find all the space it needs.
  68  */
  69 typedef struct xfs_bmap_free
  70 {
  71         xfs_bmap_free_item_t    *xbf_first;     /* list of to-be-free extents */
  72         int                     xbf_count;      /* count of items on list */
  73         int                     xbf_low;        /* alloc in low mode */
  74 } xfs_bmap_free_t;
  75
  76 #define XFS_BMAP_MAX_NMAP       4
  77
  78 /*
  79  * Flags for xfs_bmapi
  80  */
  81 #define XFS_BMAPI_WRITE         0x001   /* write operation: allocate space */
  82 #define XFS_BMAPI_DELAY         0x002   /* delayed write operation */
  83 #define XFS_BMAPI_ENTIRE        0x004   /* return entire extent, not trimmed */
  84 #define XFS_BMAPI_METADATA      0x008   /* mapping metadata not user data */
  85 #define XFS_BMAPI_EXACT         0x010   /* allocate only to spec'd bounds */
  86 #define XFS_BMAPI_ATTRFORK      0x020   /* use attribute fork not data */
  87 #define XFS_BMAPI_ASYNC         0x040   /* bunmapi xactions can be async */
  88 #define XFS_BMAPI_RSVBLOCKS     0x080   /* OK to alloc. reserved data blocks */
  89 #define XFS_BMAPI_PREALLOC      0x100   /* preallocation op: unwritten space */
  90 #define XFS_BMAPI_IGSTATE       0x200   /* Ignore state - */
  91                                         /* combine contig. space */
  92 #define XFS_BMAPI_CONTIG        0x400   /* must allocate only one extent */
  93 /*      XFS_BMAPI_DIRECT_IO     0x800   */
  94 #define XFS_BMAPI_CONVERT       0x1000  /* unwritten extent conversion - */
  95                                         /* need write cache flushing and no */
  96                                         /* additional allocation alignments */
  97
  98 #define XFS_BMAPI_FLAGS \
  99         { XFS_BMAPI_WRITE,      "WRITE" }, \
 100         { XFS_BMAPI_DELAY,      "DELAY" }, \
 101         { XFS_BMAPI_ENTIRE,     "ENTIRE" }, \
 102         { XFS_BMAPI_METADATA,   "METADATA" }, \
 103         { XFS_BMAPI_EXACT,      "EXACT" }, \
 104         { XFS_BMAPI_ATTRFORK,   "ATTRFORK" }, \
 105         { XFS_BMAPI_ASYNC,      "ASYNC" }, \
 106         { XFS_BMAPI_RSVBLOCKS,  "RSVBLOCKS" }, \
 107         { XFS_BMAPI_PREALLOC,   "PREALLOC" }, \
 108         { XFS_BMAPI_IGSTATE,    "IGSTATE" }, \
 109         { XFS_BMAPI_CONTIG,     "CONTIG" }, \
 110         { XFS_BMAPI_CONVERT,    "CONVERT" }
 111
 112
 113 static inline int xfs_bmapi_aflag(int w)
 114 {
 115         return (w == XFS_ATTR_FORK ? XFS_BMAPI_ATTRFORK : 0);
 116 }
 117
 118 /*
 119  * Special values for xfs_bmbt_irec_t br_startblock field.
 120  */
 121 #define DELAYSTARTBLOCK         ((xfs_fsblock_t)-1LL)
 122 #define HOLESTARTBLOCK          ((xfs_fsblock_t)-2LL)
 123
 124 static inline void xfs_bmap_init(xfs_bmap_free_t *flp, xfs_fsblock_t *fbp)
 125 {
 126         ((flp)->xbf_first = NULL, (flp)->xbf_count = 0, \
 127                 (flp)->xbf_low = 0, *(fbp) = NULLFSBLOCK);
 128 }
 129
 130 /*
 131  * Argument structure for xfs_bmap_alloc.
 132  */
 133 typedef struct xfs_bmalloca {
 134         xfs_fsblock_t           firstblock; /* i/o first block allocated */
 135         xfs_fsblock_t           rval;   /* starting block of new extent */
 136         xfs_fileoff_t           off;    /* offset in file filling in */
 137         struct xfs_trans        *tp;    /* transaction pointer */
 138         struct xfs_inode        *ip;    /* incore inode pointer */
 139         struct xfs_bmbt_irec    *prevp; /* extent before the new one */
 140         struct xfs_bmbt_irec    *gotp;  /* extent after, or delayed */
 141         xfs_extlen_t            alen;   /* i/o length asked/allocated */
 142         xfs_extlen_t            total;  /* total blocks needed for xaction */
 143         xfs_extlen_t            minlen; /* minimum allocation size (blocks) */
 144         xfs_extlen_t            minleft; /* amount must be left after alloc */
 145         char                    eof;    /* set if allocating past last extent */
 146         char                    wasdel; /* replacing a delayed allocation */
 147         char                    userdata;/* set if is user data */
 148         char                    low;    /* low on space, using seq'l ags */
 149         char                    aeof;   /* allocated space at eof */
 150         char                    conv;   /* overwriting unwritten extents */
 151 } xfs_bmalloca_t;
 152
 153 /*
 154  * Flags for xfs_bmap_add_extent*.
 155  */
 156 #define BMAP_LEFT_CONTIG        (1 << 0)
 157 #define BMAP_RIGHT_CONTIG       (1 << 1)
 158 #define BMAP_LEFT_FILLING       (1 << 2)
 159 #define BMAP_RIGHT_FILLING      (1 << 3)
 160 #define BMAP_LEFT_DELAY         (1 << 4)
 161 #define BMAP_RIGHT_DELAY        (1 << 5)
 162 #define BMAP_LEFT_VALID         (1 << 6)
 163 #define BMAP_RIGHT_VALID        (1 << 7)
 164 #define BMAP_ATTRFORK           (1 << 8)
 165
 166 #define XFS_BMAP_EXT_FLAGS \
 167         { BMAP_LEFT_CONTIG,     "LC" }, \
 168         { BMAP_RIGHT_CONTIG,    "RC" }, \
 169         { BMAP_LEFT_FILLING,    "LF" }, \
 170         { BMAP_RIGHT_FILLING,   "RF" }, \
 171         { BMAP_ATTRFORK,        "ATTR" }
 172
 173 /*
 174  * Add bmap trace insert entries for all the contents of the extent list.
 175  *
 176  * Quite excessive tracing.  Only do this for debug builds.
 177  */
 178 #if defined(__KERNEL) && defined(DEBUG)
 179 void
 180 xfs_bmap_trace_exlist(
 181         struct xfs_inode        *ip,            /* incore inode pointer */
 182         xfs_extnum_t            cnt,            /* count of entries in list */
 183         int                     whichfork,
 184         unsigned long           caller_ip);     /* data or attr fork */
 185 #define XFS_BMAP_TRACE_EXLIST(ip,c,w)   \
 186         xfs_bmap_trace_exlist(ip,c,w, _THIS_IP_)
 187 #else
 188 #define XFS_BMAP_TRACE_EXLIST(ip,c,w)
 189 #endif
 190
 191 /*
 192  * Convert inode from non-attributed to attributed.
 193  * Must not be in a transaction, ip must not be locked.
 194  */
 195 int                                     /* error code */
 196 xfs_bmap_add_attrfork(
 197         struct xfs_inode        *ip,    /* incore inode pointer */
 198         int                     size,   /* space needed for new attribute */
 199         int                     rsvd);  /* flag for reserved block allocation */
 200
 201 /*
 202  * Add the extent to the list of extents to be free at transaction end.
 203  * The list is maintained sorted (by block number).
 204  */
 205 void
 206 xfs_bmap_add_free(
 207         xfs_fsblock_t           bno,            /* fs block number of extent */
 208         xfs_filblks_t           len,            /* length of extent */
 209         xfs_bmap_free_t         *flist,         /* list of extents */
 210         struct xfs_mount        *mp);           /* mount point structure */
 211
 212 /*
 213  * Routine to clean up the free list data structure when
 214  * an error occurs during a transaction.
 215  */
 216 void
 217 xfs_bmap_cancel(
 218         xfs_bmap_free_t         *flist);        /* free list to clean up */
 219
 220 /*
 221  * Compute and fill in the value of the maximum depth of a bmap btree
 222  * in this filesystem.  Done once, during mount.
 223  */
 224 void
 225 xfs_bmap_compute_maxlevels(
 226         struct xfs_mount        *mp,    /* file system mount structure */
 227         int                     whichfork);     /* data or attr fork */
 228
 229 /*
 230  * Returns the file-relative block number of the first unused block in the file.
 231  * This is the lowest-address hole if the file has holes, else the first block
 232  * past the end of file.
 233  */
 234 int                                             /* error */
 235 xfs_bmap_first_unused(
 236         struct xfs_trans        *tp,            /* transaction pointer */
 237         struct xfs_inode        *ip,            /* incore inode */
 238         xfs_extlen_t            len,            /* size of hole to find */
 239         xfs_fileoff_t           *unused,        /* unused block num */
 240         int                     whichfork);     /* data or attr fork */
 241
 242 /*
 243  * Returns the file-relative block number of the last block + 1 before
 244  * last_block (input value) in the file.
 245  * This is not based on i_size, it is based on the extent list.
 246  * Returns 0 for local files, as they do not have an extent list.
 247  */
 248 int                                             /* error */
 249 xfs_bmap_last_before(
 250         struct xfs_trans        *tp,            /* transaction pointer */
 251         struct xfs_inode        *ip,            /* incore inode */
 252         xfs_fileoff_t           *last_block,    /* last block */
 253         int                     whichfork);     /* data or attr fork */
 254
 255 /*
 256  * Returns the file-relative block number of the first block past eof in
 257  * the file.  This is not based on i_size, it is based on the extent list.
 258  * Returns 0 for local files, as they do not have an extent list.
 259  */
 260 int                                             /* error */
 261 xfs_bmap_last_offset(
 262         struct xfs_trans        *tp,            /* transaction pointer */
 263         struct xfs_inode        *ip,            /* incore inode */
 264         xfs_fileoff_t           *unused,        /* last block num */
 265         int                     whichfork);     /* data or attr fork */
 266
 267 /*
 268  * Returns whether the selected fork of the inode has exactly one
 269  * block or not.  For the data fork we check this matches di_size,
 270  * implying the file's range is 0..bsize-1.
 271  */
 272 int
 273 xfs_bmap_one_block(
 274         struct xfs_inode        *ip,            /* incore inode */
 275         int                     whichfork);     /* data or attr fork */
 276
 277 /*
 278  * Read in the extents to iu_extents.
 279  * All inode fields are set up by caller, we just traverse the btree
 280  * and copy the records in.
 281  */
 282 int                                             /* error */
 283 xfs_bmap_read_extents(
 284         struct xfs_trans        *tp,            /* transaction pointer */
 285         struct xfs_inode        *ip,            /* incore inode */
 286         int                     whichfork);     /* data or attr fork */
 287
 288 /*
 289  * Map file blocks to filesystem blocks.
 290  * File range is given by the bno/len pair.
 291  * Adds blocks to file if a write ("flags & XFS_BMAPI_WRITE" set)
 292  * into a hole or past eof.
 293  * Only allocates blocks from a single allocation group,
 294  * to avoid locking problems.
 295  * The returned value in "firstblock" from the first call in a transaction
 296  * must be remembered and presented to subsequent calls in "firstblock".
 297  * An upper bound for the number of blocks to be allocated is supplied to
 298  * the first call in "total"; if no allocation group has that many free
 299  * blocks then the call will fail (return NULLFSBLOCK in "firstblock").
 300  */
 301 int                                             /* error */
 302 xfs_bmapi(
 303         struct xfs_trans        *tp,            /* transaction pointer */
 304         struct xfs_inode        *ip,            /* incore inode */
 305         xfs_fileoff_t           bno,            /* starting file offs. mapped */
 306         xfs_filblks_t           len,            /* length to map in file */
 307         int                     flags,          /* XFS_BMAPI_... */
 308         xfs_fsblock_t           *firstblock,    /* first allocated block
 309                                                    controls a.g. for allocs */
 310         xfs_extlen_t            total,          /* total blocks needed */
 311         struct xfs_bmbt_irec    *mval,          /* output: map values */
 312         int                     *nmap,          /* i/o: mval size/count */
 313         xfs_bmap_free_t         *flist,         /* i/o: list extents to free */
 314         xfs_extdelta_t          *delta);        /* o: change made to incore
 315                                                    extents */
 316
 317 /*
 318  * Map file blocks to filesystem blocks, simple version.
 319  * One block only, read-only.
 320  * For flags, only the XFS_BMAPI_ATTRFORK flag is examined.
 321  * For the other flag values, the effect is as if XFS_BMAPI_METADATA
 322  * was set and all the others were clear.
 323  */
 324 int                                             /* error */
 325 xfs_bmapi_single(
 326         struct xfs_trans        *tp,            /* transaction pointer */
 327         struct xfs_inode        *ip,            /* incore inode */
 328         int                     whichfork,      /* data or attr fork */
 329         xfs_fsblock_t           *fsb,           /* output: mapped block */
 330         xfs_fileoff_t           bno);           /* starting file offs. mapped */
 331
 332 /*
 333  * Unmap (remove) blocks from a file.
 334  * If nexts is nonzero then the number of extents to remove is limited to
 335  * that value.  If not all extents in the block range can be removed then
 336  * *done is set.
 337  */
 338 int                                             /* error */
 339 xfs_bunmapi(
 340         struct xfs_trans        *tp,            /* transaction pointer */
 341         struct xfs_inode        *ip,            /* incore inode */
 342         xfs_fileoff_t           bno,            /* starting offset to unmap */
 343         xfs_filblks_t           len,            /* length to unmap in file */
 344         int                     flags,          /* XFS_BMAPI_... */
 345         xfs_extnum_t            nexts,          /* number of extents max */
 346         xfs_fsblock_t           *firstblock,    /* first allocated block
 347                                                    controls a.g. for allocs */
 348         xfs_bmap_free_t         *flist,         /* i/o: list extents to free */
 349         xfs_extdelta_t          *delta,         /* o: change made to incore
 350                                                    extents */
 351         int                     *done);         /* set if not done yet */
 352
 353 /*
 354  * Check an extent list, which has just been read, for
 355  * any bit in the extent flag field.
 356  */
 357 int
 358 xfs_check_nostate_extents(
 359         struct xfs_ifork        *ifp,
 360         xfs_extnum_t            idx,
 361         xfs_extnum_t            num);
 362
 363 uint
 364 xfs_default_attroffset(
 365         struct xfs_inode        *ip);
 366
 367 #ifdef __KERNEL__
 368
 369 /*
 370  * Routine to be called at transaction's end by xfs_bmapi, xfs_bunmapi
 371  * caller.  Frees all the extents that need freeing, which must be done
 372  * last due to locking considerations.
 373  *
 374  * Return 1 if the given transaction was committed and a new one allocated,
 375  * and 0 otherwise.
 376  */
 377 int                                             /* error */
 378 xfs_bmap_finish(
 379         struct xfs_trans        **tp,           /* transaction pointer addr */
 380         xfs_bmap_free_t         *flist,         /* i/o: list extents to free */
 381         int                     *committed);    /* xact committed or not */
 382
 383 /* bmap to userspace formatter - copy to user & advance pointer */
 384 typedef int (*xfs_bmap_format_t)(void **, struct getbmapx *, int *);
 385
 386 /*
 387  * Get inode's extents as described in bmv, and format for output.
 388  */
 389 int                                             /* error code */
 390 xfs_getbmap(
 391         xfs_inode_t             *ip,
 392         struct getbmapx         *bmv,           /* user bmap structure */
 393         xfs_bmap_format_t       formatter,      /* format to user */
 394         void                    *arg);          /* formatter arg */
 395
 396 /*
 397  * Check if the endoff is outside the last extent. If so the caller will grow
 398  * the allocation to a stripe unit boundary
 399  */
 400 int
 401 xfs_bmap_eof(
 402         struct xfs_inode        *ip,
 403         xfs_fileoff_t           endoff,
 404         int                     whichfork,
 405         int                     *eof);
 406
 407 /*
 408  * Count fsblocks of the given fork.
 409  */
 410 int
 411 xfs_bmap_count_blocks(
 412         xfs_trans_t             *tp,
 413         struct xfs_inode        *ip,
 414         int                     whichfork,
 415         int                     *count);
 416
 417 #endif  /* __KERNEL__ */
 418
 419 #endif  /* __XFS_BMAP_H__ */