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_AFLAG(w)      xfs_bmapi_aflag(w)
  99 static inline int xfs_bmapi_aflag(int w)
 100 {
 101         return (w == XFS_ATTR_FORK ? XFS_BMAPI_ATTRFORK : 0);
 102 }
 103
 104 /*
 105  * Special values for xfs_bmbt_irec_t br_startblock field.
 106  */
 107 #define DELAYSTARTBLOCK         ((xfs_fsblock_t)-1LL)
 108 #define HOLESTARTBLOCK          ((xfs_fsblock_t)-2LL)
 109
 110 #define XFS_BMAP_INIT(flp,fbp)  xfs_bmap_init(flp,fbp)
 111 static inline void xfs_bmap_init(xfs_bmap_free_t *flp, xfs_fsblock_t *fbp)
 112 {
 113         ((flp)->xbf_first = NULL, (flp)->xbf_count = 0, \
 114                 (flp)->xbf_low = 0, *(fbp) = NULLFSBLOCK);
 115 }
 116
 117 /*
 118  * Argument structure for xfs_bmap_alloc.
 119  */
 120 typedef struct xfs_bmalloca {
 121         xfs_fsblock_t           firstblock; /* i/o first block allocated */
 122         xfs_fsblock_t           rval;   /* starting block of new extent */
 123         xfs_fileoff_t           off;    /* offset in file filling in */
 124         struct xfs_trans        *tp;    /* transaction pointer */
 125         struct xfs_inode        *ip;    /* incore inode pointer */
 126         struct xfs_bmbt_irec    *prevp; /* extent before the new one */
 127         struct xfs_bmbt_irec    *gotp;  /* extent after, or delayed */
 128         xfs_extlen_t            alen;   /* i/o length asked/allocated */
 129         xfs_extlen_t            total;  /* total blocks needed for xaction */
 130         xfs_extlen_t            minlen; /* mininum allocation size (blocks) */
 131         xfs_extlen_t            minleft; /* amount must be left after alloc */
 132         char                    eof;    /* set if allocating past last extent */
 133         char                    wasdel; /* replacing a delayed allocation */
 134         char                    userdata;/* set if is user data */
 135         char                    low;    /* low on space, using seq'l ags */
 136         char                    aeof;   /* allocated space at eof */
 137         char                    conv;   /* overwriting unwritten extents */
 138 } xfs_bmalloca_t;
 139
 140 #if defined(__KERNEL__) && defined(XFS_BMAP_TRACE)
 141 /*
 142  * Trace operations for bmap extent tracing
 143  */
 144 #define XFS_BMAP_KTRACE_DELETE  1
 145 #define XFS_BMAP_KTRACE_INSERT  2
 146 #define XFS_BMAP_KTRACE_PRE_UP  3
 147 #define XFS_BMAP_KTRACE_POST_UP 4
 148
 149 #define XFS_BMAP_TRACE_SIZE     4096    /* size of global trace buffer */
 150 #define XFS_BMAP_KTRACE_SIZE    32      /* size of per-inode trace buffer */
 151 extern ktrace_t *xfs_bmap_trace_buf;
 152
 153 /*
 154  * Add bmap trace insert entries for all the contents of the extent list.
 155  */
 156 void
 157 xfs_bmap_trace_exlist(
 158         const char              *fname,         /* function name */
 159         struct xfs_inode        *ip,            /* incore inode pointer */
 160         xfs_extnum_t            cnt,            /* count of entries in list */
 161         int                     whichfork);     /* data or attr fork */
 162 #define XFS_BMAP_TRACE_EXLIST(ip,c,w)   \
 163         xfs_bmap_trace_exlist(__func__,ip,c,w)
 164
 165 #else   /* __KERNEL__ && XFS_BMAP_TRACE */
 166
 167 #define XFS_BMAP_TRACE_EXLIST(ip,c,w)
 168
 169 #endif  /* __KERNEL__ && XFS_BMAP_TRACE */
 170
 171 /*
 172  * Convert inode from non-attributed to attributed.
 173  * Must not be in a transaction, ip must not be locked.
 174  */
 175 int                                     /* error code */
 176 xfs_bmap_add_attrfork(
 177         struct xfs_inode        *ip,    /* incore inode pointer */
 178         int                     size,   /* space needed for new attribute */
 179         int                     rsvd);  /* flag for reserved block allocation */
 180
 181 /*
 182  * Add the extent to the list of extents to be free at transaction end.
 183  * The list is maintained sorted (by block number).
 184  */
 185 void
 186 xfs_bmap_add_free(
 187         xfs_fsblock_t           bno,            /* fs block number of extent */
 188         xfs_filblks_t           len,            /* length of extent */
 189         xfs_bmap_free_t         *flist,         /* list of extents */
 190         struct xfs_mount        *mp);           /* mount point structure */
 191
 192 /*
 193  * Routine to clean up the free list data structure when
 194  * an error occurs during a transaction.
 195  */
 196 void
 197 xfs_bmap_cancel(
 198         xfs_bmap_free_t         *flist);        /* free list to clean up */
 199
 200 /*
 201  * Compute and fill in the value of the maximum depth of a bmap btree
 202  * in this filesystem.  Done once, during mount.
 203  */
 204 void
 205 xfs_bmap_compute_maxlevels(
 206         struct xfs_mount        *mp,    /* file system mount structure */
 207         int                     whichfork);     /* data or attr fork */
 208
 209 /*
 210  * Returns the file-relative block number of the first unused block in the file.
 211  * This is the lowest-address hole if the file has holes, else the first block
 212  * past the end of file.
 213  */
 214 int                                             /* error */
 215 xfs_bmap_first_unused(
 216         struct xfs_trans        *tp,            /* transaction pointer */
 217         struct xfs_inode        *ip,            /* incore inode */
 218         xfs_extlen_t            len,            /* size of hole to find */
 219         xfs_fileoff_t           *unused,        /* unused block num */
 220         int                     whichfork);     /* data or attr fork */
 221
 222 /*
 223  * Returns the file-relative block number of the last block + 1 before
 224  * last_block (input value) in the file.
 225  * This is not based on i_size, it is based on the extent list.
 226  * Returns 0 for local files, as they do not have an extent list.
 227  */
 228 int                                             /* error */
 229 xfs_bmap_last_before(
 230         struct xfs_trans        *tp,            /* transaction pointer */
 231         struct xfs_inode        *ip,            /* incore inode */
 232         xfs_fileoff_t           *last_block,    /* last block */
 233         int                     whichfork);     /* data or attr fork */
 234
 235 /*
 236  * Returns the file-relative block number of the first block past eof in
 237  * the file.  This is not based on i_size, it is based on the extent list.
 238  * Returns 0 for local files, as they do not have an extent list.
 239  */
 240 int                                             /* error */
 241 xfs_bmap_last_offset(
 242         struct xfs_trans        *tp,            /* transaction pointer */
 243         struct xfs_inode        *ip,            /* incore inode */
 244         xfs_fileoff_t           *unused,        /* last block num */
 245         int                     whichfork);     /* data or attr fork */
 246
 247 /*
 248  * Returns whether the selected fork of the inode has exactly one
 249  * block or not.  For the data fork we check this matches di_size,
 250  * implying the file's range is 0..bsize-1.
 251  */
 252 int
 253 xfs_bmap_one_block(
 254         struct xfs_inode        *ip,            /* incore inode */
 255         int                     whichfork);     /* data or attr fork */
 256
 257 /*
 258  * Read in the extents to iu_extents.
 259  * All inode fields are set up by caller, we just traverse the btree
 260  * and copy the records in.
 261  */
 262 int                                             /* error */
 263 xfs_bmap_read_extents(
 264         struct xfs_trans        *tp,            /* transaction pointer */
 265         struct xfs_inode        *ip,            /* incore inode */
 266         int                     whichfork);     /* data or attr fork */
 267
 268 /*
 269  * Map file blocks to filesystem blocks.
 270  * File range is given by the bno/len pair.
 271  * Adds blocks to file if a write ("flags & XFS_BMAPI_WRITE" set)
 272  * into a hole or past eof.
 273  * Only allocates blocks from a single allocation group,
 274  * to avoid locking problems.
 275  * The returned value in "firstblock" from the first call in a transaction
 276  * must be remembered and presented to subsequent calls in "firstblock".
 277  * An upper bound for the number of blocks to be allocated is supplied to
 278  * the first call in "total"; if no allocation group has that many free
 279  * blocks then the call will fail (return NULLFSBLOCK in "firstblock").
 280  */
 281 int                                             /* error */
 282 xfs_bmapi(
 283         struct xfs_trans        *tp,            /* transaction pointer */
 284         struct xfs_inode        *ip,            /* incore inode */
 285         xfs_fileoff_t           bno,            /* starting file offs. mapped */
 286         xfs_filblks_t           len,            /* length to map in file */
 287         int                     flags,          /* XFS_BMAPI_... */
 288         xfs_fsblock_t           *firstblock,    /* first allocated block
 289                                                    controls a.g. for allocs */
 290         xfs_extlen_t            total,          /* total blocks needed */
 291         struct xfs_bmbt_irec    *mval,          /* output: map values */
 292         int                     *nmap,          /* i/o: mval size/count */
 293         xfs_bmap_free_t         *flist,         /* i/o: list extents to free */
 294         xfs_extdelta_t          *delta);        /* o: change made to incore
 295                                                    extents */
 296
 297 /*
 298  * Map file blocks to filesystem blocks, simple version.
 299  * One block only, read-only.
 300  * For flags, only the XFS_BMAPI_ATTRFORK flag is examined.
 301  * For the other flag values, the effect is as if XFS_BMAPI_METADATA
 302  * was set and all the others were clear.
 303  */
 304 int                                             /* error */
 305 xfs_bmapi_single(
 306         struct xfs_trans        *tp,            /* transaction pointer */
 307         struct xfs_inode        *ip,            /* incore inode */
 308         int                     whichfork,      /* data or attr fork */
 309         xfs_fsblock_t           *fsb,           /* output: mapped block */
 310         xfs_fileoff_t           bno);           /* starting file offs. mapped */
 311
 312 /*
 313  * Unmap (remove) blocks from a file.
 314  * If nexts is nonzero then the number of extents to remove is limited to
 315  * that value.  If not all extents in the block range can be removed then
 316  * *done is set.
 317  */
 318 int                                             /* error */
 319 xfs_bunmapi(
 320         struct xfs_trans        *tp,            /* transaction pointer */
 321         struct xfs_inode        *ip,            /* incore inode */
 322         xfs_fileoff_t           bno,            /* starting offset to unmap */
 323         xfs_filblks_t           len,            /* length to unmap in file */
 324         int                     flags,          /* XFS_BMAPI_... */
 325         xfs_extnum_t            nexts,          /* number of extents max */
 326         xfs_fsblock_t           *firstblock,    /* first allocated block
 327                                                    controls a.g. for allocs */
 328         xfs_bmap_free_t         *flist,         /* i/o: list extents to free */
 329         xfs_extdelta_t          *delta,         /* o: change made to incore
 330                                                    extents */
 331         int                     *done);         /* set if not done yet */
 332
 333 /*
 334  * Check an extent list, which has just been read, for
 335  * any bit in the extent flag field.
 336  */
 337 int
 338 xfs_check_nostate_extents(
 339         struct xfs_ifork        *ifp,
 340         xfs_extnum_t            idx,
 341         xfs_extnum_t            num);
 342
 343 #ifdef __KERNEL__
 344
 345 /*
 346  * Routine to be called at transaction's end by xfs_bmapi, xfs_bunmapi
 347  * caller.  Frees all the extents that need freeing, which must be done
 348  * last due to locking considerations.
 349  *
 350  * Return 1 if the given transaction was committed and a new one allocated,
 351  * and 0 otherwise.
 352  */
 353 int                                             /* error */
 354 xfs_bmap_finish(
 355         struct xfs_trans        **tp,           /* transaction pointer addr */
 356         xfs_bmap_free_t         *flist,         /* i/o: list extents to free */
 357         int                     *committed);    /* xact committed or not */
 358
 359 /*
 360  * Fcntl interface to xfs_bmapi.
 361  */
 362 int                                             /* error code */
 363 xfs_getbmap(
 364         xfs_inode_t             *ip,
 365         struct getbmap          *bmv,           /* user bmap structure */
 366         void                    __user *ap,     /* pointer to user's array */
 367         int                     iflags);        /* interface flags */
 368
 369 /*
 370  * Check if the endoff is outside the last extent. If so the caller will grow
 371  * the allocation to a stripe unit boundary
 372  */
 373 int
 374 xfs_bmap_eof(
 375         struct xfs_inode        *ip,
 376         xfs_fileoff_t           endoff,
 377         int                     whichfork,
 378         int                     *eof);
 379
 380 /*
 381  * Count fsblocks of the given fork.
 382  */
 383 int
 384 xfs_bmap_count_blocks(
 385         xfs_trans_t             *tp,
 386         struct xfs_inode        *ip,
 387         int                     whichfork,
 388         int                     *count);
 389
 390 /*
 391  * Search the extent records for the entry containing block bno.
 392  * If bno lies in a hole, point to the next entry.  If bno lies
 393  * past eof, *eofp will be set, and *prevp will contain the last
 394  * entry (null if none).  Else, *lastxp will be set to the index
 395  * of the found entry; *gotp will contain the entry.
 396  */
 397 xfs_bmbt_rec_host_t *
 398 xfs_bmap_search_multi_extents(struct xfs_ifork *, xfs_fileoff_t, int *,
 399                         xfs_extnum_t *, xfs_bmbt_irec_t *, xfs_bmbt_irec_t *);
 400
 401 #endif  /* __KERNEL__ */
 402
 403 #endif  /* __XFS_BMAP_H__ */