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  * List of extents to be free "later".
  32  * The list is kept sorted on xbf_startblock.
  33  */
  34 typedef struct xfs_bmap_free_item
  35 {
  36         xfs_fsblock_t           xbfi_startblock;/* starting fs block number */
  37         xfs_extlen_t            xbfi_blockcount;/* number of blocks in extent */
  38         struct xfs_bmap_free_item *xbfi_next;   /* link to next entry */
  39 } xfs_bmap_free_item_t;
  40
  41 /*
  42  * Header for free extent list.
  43  *
  44  * xbf_low is used by the allocator to activate the lowspace algorithm -
  45  * when free space is running low the extent allocator may choose to
  46  * allocate an extent from an AG without leaving sufficient space for
  47  * a btree split when inserting the new extent.  In this case the allocator
  48  * will enable the lowspace algorithm which is supposed to allow further
  49  * allocations (such as btree splits and newroots) to allocate from
  50  * sequential AGs.  In order to avoid locking AGs out of order the lowspace
  51  * algorithm will start searching for free space from AG 0.  If the correct
  52  * transaction reservations have been made then this algorithm will eventually
  53  * find all the space it needs.
  54  */
  55 typedef struct xfs_bmap_free
  56 {
  57         xfs_bmap_free_item_t    *xbf_first;     /* list of to-be-free extents */
  58         int                     xbf_count;      /* count of items on list */
  59         int                     xbf_low;        /* alloc in low mode */
  60 } xfs_bmap_free_t;
  61
  62 #define XFS_BMAP_MAX_NMAP       4
  63
  64 /*
  65  * Flags for xfs_bmapi
  66  */
  67 #define XFS_BMAPI_WRITE         0x001   /* write operation: allocate space */
  68 #define XFS_BMAPI_DELAY         0x002   /* delayed write operation */
  69 #define XFS_BMAPI_ENTIRE        0x004   /* return entire extent, not trimmed */
  70 #define XFS_BMAPI_METADATA      0x008   /* mapping metadata not user data */
  71 #define XFS_BMAPI_ATTRFORK      0x010   /* use attribute fork not data */
  72 #define XFS_BMAPI_RSVBLOCKS     0x020   /* OK to alloc. reserved data blocks */
  73 #define XFS_BMAPI_PREALLOC      0x040   /* preallocation op: unwritten space */
  74 #define XFS_BMAPI_IGSTATE       0x080   /* Ignore state - */
  75                                         /* combine contig. space */
  76 #define XFS_BMAPI_CONTIG        0x100   /* must allocate only one extent */
  77 #define XFS_BMAPI_CONVERT       0x200   /* unwritten extent conversion - */
  78                                         /* need write cache flushing and no */
  79                                         /* additional allocation alignments */
  80
  81 #define XFS_BMAPI_FLAGS \
  82         { XFS_BMAPI_WRITE,      "WRITE" }, \
  83         { XFS_BMAPI_DELAY,      "DELAY" }, \
  84         { XFS_BMAPI_ENTIRE,     "ENTIRE" }, \
  85         { XFS_BMAPI_METADATA,   "METADATA" }, \
  86         { XFS_BMAPI_ATTRFORK,   "ATTRFORK" }, \
  87         { XFS_BMAPI_RSVBLOCKS,  "RSVBLOCKS" }, \
  88         { XFS_BMAPI_PREALLOC,   "PREALLOC" }, \
  89         { XFS_BMAPI_IGSTATE,    "IGSTATE" }, \
  90         { XFS_BMAPI_CONTIG,     "CONTIG" }, \
  91         { XFS_BMAPI_CONVERT,    "CONVERT" }
  92
  93
  94 static inline int xfs_bmapi_aflag(int w)
  95 {
  96         return (w == XFS_ATTR_FORK ? XFS_BMAPI_ATTRFORK : 0);
  97 }
  98
  99 /*
 100  * Special values for xfs_bmbt_irec_t br_startblock field.
 101  */
 102 #define DELAYSTARTBLOCK         ((xfs_fsblock_t)-1LL)
 103 #define HOLESTARTBLOCK          ((xfs_fsblock_t)-2LL)
 104
 105 static inline void xfs_bmap_init(xfs_bmap_free_t *flp, xfs_fsblock_t *fbp)
 106 {
 107         ((flp)->xbf_first = NULL, (flp)->xbf_count = 0, \
 108                 (flp)->xbf_low = 0, *(fbp) = NULLFSBLOCK);
 109 }
 110
 111 /*
 112  * Argument structure for xfs_bmap_alloc.
 113  */
 114 typedef struct xfs_bmalloca {
 115         xfs_fsblock_t           firstblock; /* i/o first block allocated */
 116         xfs_fsblock_t           rval;   /* starting block of new extent */
 117         xfs_fileoff_t           off;    /* offset in file filling in */
 118         struct xfs_trans        *tp;    /* transaction pointer */
 119         struct xfs_inode        *ip;    /* incore inode pointer */
 120         struct xfs_bmbt_irec    *prevp; /* extent before the new one */
 121         struct xfs_bmbt_irec    *gotp;  /* extent after, or delayed */
 122         xfs_extlen_t            alen;   /* i/o length asked/allocated */
 123         xfs_extlen_t            total;  /* total blocks needed for xaction */
 124         xfs_extlen_t            minlen; /* minimum allocation size (blocks) */
 125         xfs_extlen_t            minleft; /* amount must be left after alloc */
 126         char                    eof;    /* set if allocating past last extent */
 127         char                    wasdel; /* replacing a delayed allocation */
 128         char                    userdata;/* set if is user data */
 129         char                    low;    /* low on space, using seq'l ags */
 130         char                    aeof;   /* allocated space at eof */
 131         char                    conv;   /* overwriting unwritten extents */
 132 } xfs_bmalloca_t;
 133
 134 /*
 135  * Flags for xfs_bmap_add_extent*.
 136  */
 137 #define BMAP_LEFT_CONTIG        (1 << 0)
 138 #define BMAP_RIGHT_CONTIG       (1 << 1)
 139 #define BMAP_LEFT_FILLING       (1 << 2)
 140 #define BMAP_RIGHT_FILLING      (1 << 3)
 141 #define BMAP_LEFT_DELAY         (1 << 4)
 142 #define BMAP_RIGHT_DELAY        (1 << 5)
 143 #define BMAP_LEFT_VALID         (1 << 6)
 144 #define BMAP_RIGHT_VALID        (1 << 7)
 145 #define BMAP_ATTRFORK           (1 << 8)
 146
 147 #define XFS_BMAP_EXT_FLAGS \
 148         { BMAP_LEFT_CONTIG,     "LC" }, \
 149         { BMAP_RIGHT_CONTIG,    "RC" }, \
 150         { BMAP_LEFT_FILLING,    "LF" }, \
 151         { BMAP_RIGHT_FILLING,   "RF" }, \
 152         { BMAP_ATTRFORK,        "ATTR" }
 153
 154 /*
 155  * Add bmap trace insert entries for all the contents of the extent list.
 156  *
 157  * Quite excessive tracing.  Only do this for debug builds.
 158  */
 159 #if defined(__KERNEL) && defined(DEBUG)
 160 void
 161 xfs_bmap_trace_exlist(
 162         struct xfs_inode        *ip,            /* incore inode pointer */
 163         xfs_extnum_t            cnt,            /* count of entries in list */
 164         int                     whichfork,
 165         unsigned long           caller_ip);     /* data or attr fork */
 166 #define XFS_BMAP_TRACE_EXLIST(ip,c,w)   \
 167         xfs_bmap_trace_exlist(ip,c,w, _THIS_IP_)
 168 #else
 169 #define XFS_BMAP_TRACE_EXLIST(ip,c,w)
 170 #endif
 171
 172 /*
 173  * Convert inode from non-attributed to attributed.
 174  * Must not be in a transaction, ip must not be locked.
 175  */
 176 int                                     /* error code */
 177 xfs_bmap_add_attrfork(
 178         struct xfs_inode        *ip,    /* incore inode pointer */
 179         int                     size,   /* space needed for new attribute */
 180         int                     rsvd);  /* flag for reserved block allocation */
 181
 182 /*
 183  * Add the extent to the list of extents to be free at transaction end.
 184  * The list is maintained sorted (by block number).
 185  */
 186 void
 187 xfs_bmap_add_free(
 188         xfs_fsblock_t           bno,            /* fs block number of extent */
 189         xfs_filblks_t           len,            /* length of extent */
 190         xfs_bmap_free_t         *flist,         /* list of extents */
 191         struct xfs_mount        *mp);           /* mount point structure */
 192
 193 /*
 194  * Routine to clean up the free list data structure when
 195  * an error occurs during a transaction.
 196  */
 197 void
 198 xfs_bmap_cancel(
 199         xfs_bmap_free_t         *flist);        /* free list to clean up */
 200
 201 /*
 202  * Compute and fill in the value of the maximum depth of a bmap btree
 203  * in this filesystem.  Done once, during mount.
 204  */
 205 void
 206 xfs_bmap_compute_maxlevels(
 207         struct xfs_mount        *mp,    /* file system mount structure */
 208         int                     whichfork);     /* data or attr fork */
 209
 210 /*
 211  * Returns the file-relative block number of the first unused block in the file.
 212  * This is the lowest-address hole if the file has holes, else the first block
 213  * past the end of file.
 214  */
 215 int                                             /* error */
 216 xfs_bmap_first_unused(
 217         struct xfs_trans        *tp,            /* transaction pointer */
 218         struct xfs_inode        *ip,            /* incore inode */
 219         xfs_extlen_t            len,            /* size of hole to find */
 220         xfs_fileoff_t           *unused,        /* unused block num */
 221         int                     whichfork);     /* data or attr fork */
 222
 223 /*
 224  * Returns the file-relative block number of the last block + 1 before
 225  * last_block (input value) in the file.
 226  * This is not based on i_size, it is based on the extent list.
 227  * Returns 0 for local files, as they do not have an extent list.
 228  */
 229 int                                             /* error */
 230 xfs_bmap_last_before(
 231         struct xfs_trans        *tp,            /* transaction pointer */
 232         struct xfs_inode        *ip,            /* incore inode */
 233         xfs_fileoff_t           *last_block,    /* last block */
 234         int                     whichfork);     /* data or attr fork */
 235
 236 /*
 237  * Returns the file-relative block number of the first block past eof in
 238  * the file.  This is not based on i_size, it is based on the extent list.
 239  * Returns 0 for local files, as they do not have an extent list.
 240  */
 241 int                                             /* error */
 242 xfs_bmap_last_offset(
 243         struct xfs_trans        *tp,            /* transaction pointer */
 244         struct xfs_inode        *ip,            /* incore inode */
 245         xfs_fileoff_t           *unused,        /* last block num */
 246         int                     whichfork);     /* data or attr fork */
 247
 248 /*
 249  * Returns whether the selected fork of the inode has exactly one
 250  * block or not.  For the data fork we check this matches di_size,
 251  * implying the file's range is 0..bsize-1.
 252  */
 253 int
 254 xfs_bmap_one_block(
 255         struct xfs_inode        *ip,            /* incore inode */
 256         int                     whichfork);     /* data or attr fork */
 257
 258 /*
 259  * Read in the extents to iu_extents.
 260  * All inode fields are set up by caller, we just traverse the btree
 261  * and copy the records in.
 262  */
 263 int                                             /* error */
 264 xfs_bmap_read_extents(
 265         struct xfs_trans        *tp,            /* transaction pointer */
 266         struct xfs_inode        *ip,            /* incore inode */
 267         int                     whichfork);     /* data or attr fork */
 268
 269 /*
 270  * Map file blocks to filesystem blocks.
 271  * File range is given by the bno/len pair.
 272  * Adds blocks to file if a write ("flags & XFS_BMAPI_WRITE" set)
 273  * into a hole or past eof.
 274  * Only allocates blocks from a single allocation group,
 275  * to avoid locking problems.
 276  * The returned value in "firstblock" from the first call in a transaction
 277  * must be remembered and presented to subsequent calls in "firstblock".
 278  * An upper bound for the number of blocks to be allocated is supplied to
 279  * the first call in "total"; if no allocation group has that many free
 280  * blocks then the call will fail (return NULLFSBLOCK in "firstblock").
 281  */
 282 int                                             /* error */
 283 xfs_bmapi(
 284         struct xfs_trans        *tp,            /* transaction pointer */
 285         struct xfs_inode        *ip,            /* incore inode */
 286         xfs_fileoff_t           bno,            /* starting file offs. mapped */
 287         xfs_filblks_t           len,            /* length to map in file */
 288         int                     flags,          /* XFS_BMAPI_... */
 289         xfs_fsblock_t           *firstblock,    /* first allocated block
 290                                                    controls a.g. for allocs */
 291         xfs_extlen_t            total,          /* total blocks needed */
 292         struct xfs_bmbt_irec    *mval,          /* output: map values */
 293         int                     *nmap,          /* i/o: mval size/count */
 294         xfs_bmap_free_t         *flist);        /* i/o: list extents to free */
 295
 296 /*
 297  * Map file blocks to filesystem blocks, simple version.
 298  * One block only, read-only.
 299  * For flags, only the XFS_BMAPI_ATTRFORK flag is examined.
 300  * For the other flag values, the effect is as if XFS_BMAPI_METADATA
 301  * was set and all the others were clear.
 302  */
 303 int                                             /* error */
 304 xfs_bmapi_single(
 305         struct xfs_trans        *tp,            /* transaction pointer */
 306         struct xfs_inode        *ip,            /* incore inode */
 307         int                     whichfork,      /* data or attr fork */
 308         xfs_fsblock_t           *fsb,           /* output: mapped block */
 309         xfs_fileoff_t           bno);           /* starting file offs. mapped */
 310
 311 /*
 312  * Unmap (remove) blocks from a file.
 313  * If nexts is nonzero then the number of extents to remove is limited to
 314  * that value.  If not all extents in the block range can be removed then
 315  * *done is set.
 316  */
 317 int                                             /* error */
 318 xfs_bunmapi(
 319         struct xfs_trans        *tp,            /* transaction pointer */
 320         struct xfs_inode        *ip,            /* incore inode */
 321         xfs_fileoff_t           bno,            /* starting offset to unmap */
 322         xfs_filblks_t           len,            /* length to unmap in file */
 323         int                     flags,          /* XFS_BMAPI_... */
 324         xfs_extnum_t            nexts,          /* number of extents max */
 325         xfs_fsblock_t           *firstblock,    /* first allocated block
 326                                                    controls a.g. for allocs */
 327         xfs_bmap_free_t         *flist,         /* i/o: list extents to free */
 328         int                     *done);         /* set if not done yet */
 329
 330 /*
 331  * Check an extent list, which has just been read, for
 332  * any bit in the extent flag field.
 333  */
 334 int
 335 xfs_check_nostate_extents(
 336         struct xfs_ifork        *ifp,
 337         xfs_extnum_t            idx,
 338         xfs_extnum_t            num);
 339
 340 uint
 341 xfs_default_attroffset(
 342         struct xfs_inode        *ip);
 343
 344 #ifdef __KERNEL__
 345
 346 /*
 347  * Routine to be called at transaction's end by xfs_bmapi, xfs_bunmapi
 348  * caller.  Frees all the extents that need freeing, which must be done
 349  * last due to locking considerations.
 350  *
 351  * Return 1 if the given transaction was committed and a new one allocated,
 352  * and 0 otherwise.
 353  */
 354 int                                             /* error */
 355 xfs_bmap_finish(
 356         struct xfs_trans        **tp,           /* transaction pointer addr */
 357         xfs_bmap_free_t         *flist,         /* i/o: list extents to free */
 358         int                     *committed);    /* xact committed or not */
 359
 360 /* bmap to userspace formatter - copy to user & advance pointer */
 361 typedef int (*xfs_bmap_format_t)(void **, struct getbmapx *, int *);
 362
 363 /*
 364  * Get inode's extents as described in bmv, and format for output.
 365  */
 366 int                                             /* error code */
 367 xfs_getbmap(
 368         xfs_inode_t             *ip,
 369         struct getbmapx         *bmv,           /* user bmap structure */
 370         xfs_bmap_format_t       formatter,      /* format to user */
 371         void                    *arg);          /* formatter arg */
 372
 373 /*
 374  * Check if the endoff is outside the last extent. If so the caller will grow
 375  * the allocation to a stripe unit boundary
 376  */
 377 int
 378 xfs_bmap_eof(
 379         struct xfs_inode        *ip,
 380         xfs_fileoff_t           endoff,
 381         int                     whichfork,
 382         int                     *eof);
 383
 384 /*
 385  * Count fsblocks of the given fork.
 386  */
 387 int
 388 xfs_bmap_count_blocks(
 389         xfs_trans_t             *tp,
 390         struct xfs_inode        *ip,
 391         int                     whichfork,
 392         int                     *count);
 393
 394 #endif  /* __KERNEL__ */
 395
 396 #endif  /* __XFS_BMAP_H__ */