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