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