fs/xfs/xfs_bmap_btree.c

   1 /*
   2  * Copyright (c) 2000-2003,2005 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 #include "xfs.h"
  19 #include "xfs_fs.h"
  20 #include "xfs_types.h"
  21 #include "xfs_bit.h"
  22 #include "xfs_log.h"
  23 #include "xfs_trans.h"
  24 #include "xfs_sb.h"
  25 #include "xfs_ag.h"
  26 #include "xfs_mount.h"
  27 #include "xfs_bmap_btree.h"
  28 #include "xfs_alloc_btree.h"
  29 #include "xfs_ialloc_btree.h"
  30 #include "xfs_dinode.h"
  31 #include "xfs_inode.h"
  32 #include "xfs_inode_item.h"
  33 #include "xfs_alloc.h"
  34 #include "xfs_btree.h"
  35 #include "xfs_itable.h"
  36 #include "xfs_bmap.h"
  37 #include "xfs_error.h"
  38 #include "xfs_quota.h"
  39
  40 /*
  41  * Determine the extent state.
  42  */
  43 /* ARGSUSED */
  44 STATIC xfs_exntst_t
  45 xfs_extent_state(
  46         xfs_filblks_t           blks,
  47         int                     extent_flag)
  48 {
  49         if (extent_flag) {
  50                 ASSERT(blks != 0);      /* saved for DMIG */
  51                 return XFS_EXT_UNWRITTEN;
  52         }
  53         return XFS_EXT_NORM;
  54 }
  55
  56 /*
  57  * Convert on-disk form of btree root to in-memory form.
  58  */
  59 void
  60 xfs_bmdr_to_bmbt(
  61         struct xfs_mount        *mp,
  62         xfs_bmdr_block_t        *dblock,
  63         int                     dblocklen,
  64         struct xfs_btree_block  *rblock,
  65         int                     rblocklen)
  66 {
  67         int                     dmxr;
  68         xfs_bmbt_key_t          *fkp;
  69         __be64                  *fpp;
  70         xfs_bmbt_key_t          *tkp;
  71         __be64                  *tpp;
  72
  73         rblock->bb_magic = cpu_to_be32(XFS_BMAP_MAGIC);
  74         rblock->bb_level = dblock->bb_level;
  75         ASSERT(be16_to_cpu(rblock->bb_level) > 0);
  76         rblock->bb_numrecs = dblock->bb_numrecs;
  77         rblock->bb_u.l.bb_leftsib = cpu_to_be64(NULLDFSBNO);
  78         rblock->bb_u.l.bb_rightsib = cpu_to_be64(NULLDFSBNO);
  79         dmxr = xfs_bmdr_maxrecs(mp, dblocklen, 0);
  80         fkp = XFS_BMDR_KEY_ADDR(dblock, 1);
  81         tkp = XFS_BMBT_KEY_ADDR(mp, rblock, 1);
  82         fpp = XFS_BMDR_PTR_ADDR(dblock, 1, dmxr);
  83         tpp = XFS_BMAP_BROOT_PTR_ADDR(mp, rblock, 1, rblocklen);
  84         dmxr = be16_to_cpu(dblock->bb_numrecs);
  85         memcpy(tkp, fkp, sizeof(*fkp) * dmxr);
  86         memcpy(tpp, fpp, sizeof(*fpp) * dmxr);
  87 }
  88
  89 /*
  90  * Convert a compressed bmap extent record to an uncompressed form.
  91  * This code must be in sync with the routines xfs_bmbt_get_startoff,
  92  * xfs_bmbt_get_startblock, xfs_bmbt_get_blockcount and xfs_bmbt_get_state.
  93  */
  94 STATIC void
  95 __xfs_bmbt_get_all(
  96                 __uint64_t l0,
  97                 __uint64_t l1,
  98                 xfs_bmbt_irec_t *s)
  99 {
 100         int     ext_flag;
 101         xfs_exntst_t st;
 102
 103         ext_flag = (int)(l0 >> (64 - BMBT_EXNTFLAG_BITLEN));
 104         s->br_startoff = ((xfs_fileoff_t)l0 &
 105                            xfs_mask64lo(64 - BMBT_EXNTFLAG_BITLEN)) >> 9;
 106 #if XFS_BIG_BLKNOS
 107         s->br_startblock = (((xfs_fsblock_t)l0 & xfs_mask64lo(9)) << 43) |
 108                            (((xfs_fsblock_t)l1) >> 21);
 109 #else
 110 #ifdef DEBUG
 111         {
 112                 xfs_dfsbno_t    b;
 113
 114                 b = (((xfs_dfsbno_t)l0 & xfs_mask64lo(9)) << 43) |
 115                     (((xfs_dfsbno_t)l1) >> 21);
 116                 ASSERT((b >> 32) == 0 || isnulldstartblock(b));
 117                 s->br_startblock = (xfs_fsblock_t)b;
 118         }
 119 #else   /* !DEBUG */
 120         s->br_startblock = (xfs_fsblock_t)(((xfs_dfsbno_t)l1) >> 21);
 121 #endif  /* DEBUG */
 122 #endif  /* XFS_BIG_BLKNOS */
 123         s->br_blockcount = (xfs_filblks_t)(l1 & xfs_mask64lo(21));
 124         /* This is xfs_extent_state() in-line */
 125         if (ext_flag) {
 126                 ASSERT(s->br_blockcount != 0);  /* saved for DMIG */
 127                 st = XFS_EXT_UNWRITTEN;
 128         } else
 129                 st = XFS_EXT_NORM;
 130         s->br_state = st;
 131 }
 132
 133 void
 134 xfs_bmbt_get_all(
 135         xfs_bmbt_rec_host_t *r,
 136         xfs_bmbt_irec_t *s)
 137 {
 138         __xfs_bmbt_get_all(r->l0, r->l1, s);
 139 }
 140
 141 /*
 142  * Extract the blockcount field from an in memory bmap extent record.
 143  */
 144 xfs_filblks_t
 145 xfs_bmbt_get_blockcount(
 146         xfs_bmbt_rec_host_t     *r)
 147 {
 148         return (xfs_filblks_t)(r->l1 & xfs_mask64lo(21));
 149 }
 150
 151 /*
 152  * Extract the startblock field from an in memory bmap extent record.
 153  */
 154 xfs_fsblock_t
 155 xfs_bmbt_get_startblock(
 156         xfs_bmbt_rec_host_t     *r)
 157 {
 158 #if XFS_BIG_BLKNOS
 159         return (((xfs_fsblock_t)r->l0 & xfs_mask64lo(9)) << 43) |
 160                (((xfs_fsblock_t)r->l1) >> 21);
 161 #else
 162 #ifdef DEBUG
 163         xfs_dfsbno_t    b;
 164
 165         b = (((xfs_dfsbno_t)r->l0 & xfs_mask64lo(9)) << 43) |
 166             (((xfs_dfsbno_t)r->l1) >> 21);
 167         ASSERT((b >> 32) == 0 || isnulldstartblock(b));
 168         return (xfs_fsblock_t)b;
 169 #else   /* !DEBUG */
 170         return (xfs_fsblock_t)(((xfs_dfsbno_t)r->l1) >> 21);
 171 #endif  /* DEBUG */
 172 #endif  /* XFS_BIG_BLKNOS */
 173 }
 174
 175 /*
 176  * Extract the startoff field from an in memory bmap extent record.
 177  */
 178 xfs_fileoff_t
 179 xfs_bmbt_get_startoff(
 180         xfs_bmbt_rec_host_t     *r)
 181 {
 182         return ((xfs_fileoff_t)r->l0 &
 183                  xfs_mask64lo(64 - BMBT_EXNTFLAG_BITLEN)) >> 9;
 184 }
 185
 186 xfs_exntst_t
 187 xfs_bmbt_get_state(
 188         xfs_bmbt_rec_host_t     *r)
 189 {
 190         int     ext_flag;
 191
 192         ext_flag = (int)((r->l0) >> (64 - BMBT_EXNTFLAG_BITLEN));
 193         return xfs_extent_state(xfs_bmbt_get_blockcount(r),
 194                                 ext_flag);
 195 }
 196
 197 /*
 198  * Extract the blockcount field from an on disk bmap extent record.
 199  */
 200 xfs_filblks_t
 201 xfs_bmbt_disk_get_blockcount(
 202         xfs_bmbt_rec_t  *r)
 203 {
 204         return (xfs_filblks_t)(be64_to_cpu(r->l1) & xfs_mask64lo(21));
 205 }
 206
 207 /*
 208  * Extract the startoff field from a disk format bmap extent record.
 209  */
 210 xfs_fileoff_t
 211 xfs_bmbt_disk_get_startoff(
 212         xfs_bmbt_rec_t  *r)
 213 {
 214         return ((xfs_fileoff_t)be64_to_cpu(r->l0) &
 215                  xfs_mask64lo(64 - BMBT_EXNTFLAG_BITLEN)) >> 9;
 216 }
 217
 218
 219 /*
 220  * Set all the fields in a bmap extent record from the arguments.
 221  */
 222 void
 223 xfs_bmbt_set_allf(
 224         xfs_bmbt_rec_host_t     *r,
 225         xfs_fileoff_t           startoff,
 226         xfs_fsblock_t           startblock,
 227         xfs_filblks_t           blockcount,
 228         xfs_exntst_t            state)
 229 {
 230         int             extent_flag = (state == XFS_EXT_NORM) ? 0 : 1;
 231
 232         ASSERT(state == XFS_EXT_NORM || state == XFS_EXT_UNWRITTEN);
 233         ASSERT((startoff & xfs_mask64hi(64-BMBT_STARTOFF_BITLEN)) == 0);
 234         ASSERT((blockcount & xfs_mask64hi(64-BMBT_BLOCKCOUNT_BITLEN)) == 0);
 235
 236 #if XFS_BIG_BLKNOS
 237         ASSERT((startblock & xfs_mask64hi(64-BMBT_STARTBLOCK_BITLEN)) == 0);
 238
 239         r->l0 = ((xfs_bmbt_rec_base_t)extent_flag << 63) |
 240                 ((xfs_bmbt_rec_base_t)startoff << 9) |
 241                 ((xfs_bmbt_rec_base_t)startblock >> 43);
 242         r->l1 = ((xfs_bmbt_rec_base_t)startblock << 21) |
 243                 ((xfs_bmbt_rec_base_t)blockcount &
 244                 (xfs_bmbt_rec_base_t)xfs_mask64lo(21));
 245 #else   /* !XFS_BIG_BLKNOS */
 246         if (isnullstartblock(startblock)) {
 247                 r->l0 = ((xfs_bmbt_rec_base_t)extent_flag << 63) |
 248                         ((xfs_bmbt_rec_base_t)startoff << 9) |
 249                          (xfs_bmbt_rec_base_t)xfs_mask64lo(9);
 250                 r->l1 = xfs_mask64hi(11) |
 251                           ((xfs_bmbt_rec_base_t)startblock << 21) |
 252                           ((xfs_bmbt_rec_base_t)blockcount &
 253                            (xfs_bmbt_rec_base_t)xfs_mask64lo(21));
 254         } else {
 255                 r->l0 = ((xfs_bmbt_rec_base_t)extent_flag << 63) |
 256                         ((xfs_bmbt_rec_base_t)startoff << 9);
 257                 r->l1 = ((xfs_bmbt_rec_base_t)startblock << 21) |
 258                          ((xfs_bmbt_rec_base_t)blockcount &
 259                          (xfs_bmbt_rec_base_t)xfs_mask64lo(21));
 260         }
 261 #endif  /* XFS_BIG_BLKNOS */
 262 }
 263
 264 /*
 265  * Set all the fields in a bmap extent record from the uncompressed form.
 266  */
 267 void
 268 xfs_bmbt_set_all(
 269         xfs_bmbt_rec_host_t *r,
 270         xfs_bmbt_irec_t *s)
 271 {
 272         xfs_bmbt_set_allf(r, s->br_startoff, s->br_startblock,
 273                              s->br_blockcount, s->br_state);
 274 }
 275
 276
 277 /*
 278  * Set all the fields in a disk format bmap extent record from the arguments.
 279  */
 280 void
 281 xfs_bmbt_disk_set_allf(
 282         xfs_bmbt_rec_t          *r,
 283         xfs_fileoff_t           startoff,
 284         xfs_fsblock_t           startblock,
 285         xfs_filblks_t           blockcount,
 286         xfs_exntst_t            state)
 287 {
 288         int                     extent_flag = (state == XFS_EXT_NORM) ? 0 : 1;
 289
 290         ASSERT(state == XFS_EXT_NORM || state == XFS_EXT_UNWRITTEN);
 291         ASSERT((startoff & xfs_mask64hi(64-BMBT_STARTOFF_BITLEN)) == 0);
 292         ASSERT((blockcount & xfs_mask64hi(64-BMBT_BLOCKCOUNT_BITLEN)) == 0);
 293
 294 #if XFS_BIG_BLKNOS
 295         ASSERT((startblock & xfs_mask64hi(64-BMBT_STARTBLOCK_BITLEN)) == 0);
 296
 297         r->l0 = cpu_to_be64(
 298                 ((xfs_bmbt_rec_base_t)extent_flag << 63) |
 299                  ((xfs_bmbt_rec_base_t)startoff << 9) |
 300                  ((xfs_bmbt_rec_base_t)startblock >> 43));
 301         r->l1 = cpu_to_be64(
 302                 ((xfs_bmbt_rec_base_t)startblock << 21) |
 303                  ((xfs_bmbt_rec_base_t)blockcount &
 304                   (xfs_bmbt_rec_base_t)xfs_mask64lo(21)));
 305 #else   /* !XFS_BIG_BLKNOS */
 306         if (isnullstartblock(startblock)) {
 307                 r->l0 = cpu_to_be64(
 308                         ((xfs_bmbt_rec_base_t)extent_flag << 63) |
 309                          ((xfs_bmbt_rec_base_t)startoff << 9) |
 310                           (xfs_bmbt_rec_base_t)xfs_mask64lo(9));
 311                 r->l1 = cpu_to_be64(xfs_mask64hi(11) |
 312                           ((xfs_bmbt_rec_base_t)startblock << 21) |
 313                           ((xfs_bmbt_rec_base_t)blockcount &
 314                            (xfs_bmbt_rec_base_t)xfs_mask64lo(21)));
 315         } else {
 316                 r->l0 = cpu_to_be64(
 317                         ((xfs_bmbt_rec_base_t)extent_flag << 63) |
 318                          ((xfs_bmbt_rec_base_t)startoff << 9));
 319                 r->l1 = cpu_to_be64(
 320                         ((xfs_bmbt_rec_base_t)startblock << 21) |
 321                          ((xfs_bmbt_rec_base_t)blockcount &
 322                           (xfs_bmbt_rec_base_t)xfs_mask64lo(21)));
 323         }
 324 #endif  /* XFS_BIG_BLKNOS */
 325 }
 326
 327 /*
 328  * Set all the fields in a bmap extent record from the uncompressed form.
 329  */
 330 STATIC void
 331 xfs_bmbt_disk_set_all(
 332         xfs_bmbt_rec_t  *r,
 333         xfs_bmbt_irec_t *s)
 334 {
 335         xfs_bmbt_disk_set_allf(r, s->br_startoff, s->br_startblock,
 336                                   s->br_blockcount, s->br_state);
 337 }
 338
 339 /*
 340  * Set the blockcount field in a bmap extent record.
 341  */
 342 void
 343 xfs_bmbt_set_blockcount(
 344         xfs_bmbt_rec_host_t *r,
 345         xfs_filblks_t   v)
 346 {
 347         ASSERT((v & xfs_mask64hi(43)) == 0);
 348         r->l1 = (r->l1 & (xfs_bmbt_rec_base_t)xfs_mask64hi(43)) |
 349                   (xfs_bmbt_rec_base_t)(v & xfs_mask64lo(21));
 350 }
 351
 352 /*
 353  * Set the startblock field in a bmap extent record.
 354  */
 355 void
 356 xfs_bmbt_set_startblock(
 357         xfs_bmbt_rec_host_t *r,
 358         xfs_fsblock_t   v)
 359 {
 360 #if XFS_BIG_BLKNOS
 361         ASSERT((v & xfs_mask64hi(12)) == 0);
 362         r->l0 = (r->l0 & (xfs_bmbt_rec_base_t)xfs_mask64hi(55)) |
 363                   (xfs_bmbt_rec_base_t)(v >> 43);
 364         r->l1 = (r->l1 & (xfs_bmbt_rec_base_t)xfs_mask64lo(21)) |
 365                   (xfs_bmbt_rec_base_t)(v << 21);
 366 #else   /* !XFS_BIG_BLKNOS */
 367         if (isnullstartblock(v)) {
 368                 r->l0 |= (xfs_bmbt_rec_base_t)xfs_mask64lo(9);
 369                 r->l1 = (xfs_bmbt_rec_base_t)xfs_mask64hi(11) |
 370                           ((xfs_bmbt_rec_base_t)v << 21) |
 371                           (r->l1 & (xfs_bmbt_rec_base_t)xfs_mask64lo(21));
 372         } else {
 373                 r->l0 &= ~(xfs_bmbt_rec_base_t)xfs_mask64lo(9);
 374                 r->l1 = ((xfs_bmbt_rec_base_t)v << 21) |
 375                           (r->l1 & (xfs_bmbt_rec_base_t)xfs_mask64lo(21));
 376         }
 377 #endif  /* XFS_BIG_BLKNOS */
 378 }
 379
 380 /*
 381  * Set the startoff field in a bmap extent record.
 382  */
 383 void
 384 xfs_bmbt_set_startoff(
 385         xfs_bmbt_rec_host_t *r,
 386         xfs_fileoff_t   v)
 387 {
 388         ASSERT((v & xfs_mask64hi(9)) == 0);
 389         r->l0 = (r->l0 & (xfs_bmbt_rec_base_t) xfs_mask64hi(1)) |
 390                 ((xfs_bmbt_rec_base_t)v << 9) |
 391                   (r->l0 & (xfs_bmbt_rec_base_t)xfs_mask64lo(9));
 392 }
 393
 394 /*
 395  * Set the extent state field in a bmap extent record.
 396  */
 397 void
 398 xfs_bmbt_set_state(
 399         xfs_bmbt_rec_host_t *r,
 400         xfs_exntst_t    v)
 401 {
 402         ASSERT(v == XFS_EXT_NORM || v == XFS_EXT_UNWRITTEN);
 403         if (v == XFS_EXT_NORM)
 404                 r->l0 &= xfs_mask64lo(64 - BMBT_EXNTFLAG_BITLEN);
 405         else
 406                 r->l0 |= xfs_mask64hi(BMBT_EXNTFLAG_BITLEN);
 407 }
 408
 409 /*
 410  * Convert in-memory form of btree root to on-disk form.
 411  */
 412 void
 413 xfs_bmbt_to_bmdr(
 414         struct xfs_mount        *mp,
 415         struct xfs_btree_block  *rblock,
 416         int                     rblocklen,
 417         xfs_bmdr_block_t        *dblock,
 418         int                     dblocklen)
 419 {
 420         int                     dmxr;
 421         xfs_bmbt_key_t          *fkp;
 422         __be64                  *fpp;
 423         xfs_bmbt_key_t          *tkp;
 424         __be64                  *tpp;
 425
 426         ASSERT(rblock->bb_magic == cpu_to_be32(XFS_BMAP_MAGIC));
 427         ASSERT(rblock->bb_u.l.bb_leftsib == cpu_to_be64(NULLDFSBNO));
 428         ASSERT(rblock->bb_u.l.bb_rightsib == cpu_to_be64(NULLDFSBNO));
 429         ASSERT(rblock->bb_level != 0);
 430         dblock->bb_level = rblock->bb_level;
 431         dblock->bb_numrecs = rblock->bb_numrecs;
 432         dmxr = xfs_bmdr_maxrecs(mp, dblocklen, 0);
 433         fkp = XFS_BMBT_KEY_ADDR(mp, rblock, 1);
 434         tkp = XFS_BMDR_KEY_ADDR(dblock, 1);
 435         fpp = XFS_BMAP_BROOT_PTR_ADDR(mp, rblock, 1, rblocklen);
 436         tpp = XFS_BMDR_PTR_ADDR(dblock, 1, dmxr);
 437         dmxr = be16_to_cpu(dblock->bb_numrecs);
 438         memcpy(tkp, fkp, sizeof(*fkp) * dmxr);
 439         memcpy(tpp, fpp, sizeof(*fpp) * dmxr);
 440 }
 441
 442 /*
 443  * Check extent records, which have just been read, for
 444  * any bit in the extent flag field. ASSERT on debug
 445  * kernels, as this condition should not occur.
 446  * Return an error condition (1) if any flags found,
 447  * otherwise return 0.
 448  */
 449
 450 int
 451 xfs_check_nostate_extents(
 452         xfs_ifork_t             *ifp,
 453         xfs_extnum_t            idx,
 454         xfs_extnum_t            num)
 455 {
 456         for (; num > 0; num--, idx++) {
 457                 xfs_bmbt_rec_host_t *ep = xfs_iext_get_ext(ifp, idx);
 458                 if ((ep->l0 >>
 459                      (64 - BMBT_EXNTFLAG_BITLEN)) != 0) {
 460                         ASSERT(0);
 461                         return 1;
 462                 }
 463         }
 464         return 0;
 465 }
 466
 467
 468 STATIC struct xfs_btree_cur *
 469 xfs_bmbt_dup_cursor(
 470         struct xfs_btree_cur    *cur)
 471 {
 472         struct xfs_btree_cur    *new;
 473
 474         new = xfs_bmbt_init_cursor(cur->bc_mp, cur->bc_tp,
 475                         cur->bc_private.b.ip, cur->bc_private.b.whichfork);
 476
 477         /*
 478          * Copy the firstblock, flist, and flags values,
 479          * since init cursor doesn't get them.
 480          */
 481         new->bc_private.b.firstblock = cur->bc_private.b.firstblock;
 482         new->bc_private.b.flist = cur->bc_private.b.flist;
 483         new->bc_private.b.flags = cur->bc_private.b.flags;
 484
 485         return new;
 486 }
 487
 488 STATIC void
 489 xfs_bmbt_update_cursor(
 490         struct xfs_btree_cur    *src,
 491         struct xfs_btree_cur    *dst)
 492 {
 493         ASSERT((dst->bc_private.b.firstblock != NULLFSBLOCK) ||
 494                (dst->bc_private.b.ip->i_d.di_flags & XFS_DIFLAG_REALTIME));
 495         ASSERT(dst->bc_private.b.flist == src->bc_private.b.flist);
 496
 497         dst->bc_private.b.allocated += src->bc_private.b.allocated;
 498         dst->bc_private.b.firstblock = src->bc_private.b.firstblock;
 499
 500         src->bc_private.b.allocated = 0;
 501 }
 502
 503 STATIC int
 504 xfs_bmbt_alloc_block(
 505         struct xfs_btree_cur    *cur,
 506         union xfs_btree_ptr     *start,
 507         union xfs_btree_ptr     *new,
 508         int                     length,
 509         int                     *stat)
 510 {
 511         xfs_alloc_arg_t         args;           /* block allocation args */
 512         int                     error;          /* error return value */
 513
 514         memset(&args, 0, sizeof(args));
 515         args.tp = cur->bc_tp;
 516         args.mp = cur->bc_mp;
 517         args.fsbno = cur->bc_private.b.firstblock;
 518         args.firstblock = args.fsbno;
 519
 520         if (args.fsbno == NULLFSBLOCK) {
 521                 args.fsbno = be64_to_cpu(start->l);
 522                 args.type = XFS_ALLOCTYPE_START_BNO;
 523                 /*
 524                  * Make sure there is sufficient room left in the AG to
 525                  * complete a full tree split for an extent insert.  If
 526                  * we are converting the middle part of an extent then
 527                  * we may need space for two tree splits.
 528                  *
 529                  * We are relying on the caller to make the correct block
 530                  * reservation for this operation to succeed.  If the
 531                  * reservation amount is insufficient then we may fail a
 532                  * block allocation here and corrupt the filesystem.
 533                  */
 534                 args.minleft = xfs_trans_get_block_res(args.tp);
 535         } else if (cur->bc_private.b.flist->xbf_low) {
 536                 args.type = XFS_ALLOCTYPE_START_BNO;
 537         } else {
 538                 args.type = XFS_ALLOCTYPE_NEAR_BNO;
 539         }
 540
 541         args.minlen = args.maxlen = args.prod = 1;
 542         args.wasdel = cur->bc_private.b.flags & XFS_BTCUR_BPRV_WASDEL;
 543         if (!args.wasdel && xfs_trans_get_block_res(args.tp) == 0) {
 544                 error = XFS_ERROR(ENOSPC);
 545                 goto error0;
 546         }
 547         error = xfs_alloc_vextent(&args);
 548         if (error)
 549                 goto error0;
 550
 551         if (args.fsbno == NULLFSBLOCK && args.minleft) {
 552                 /*
 553                  * Could not find an AG with enough free space to satisfy
 554                  * a full btree split.  Try again without minleft and if
 555                  * successful activate the lowspace algorithm.
 556                  */
 557                 args.fsbno = 0;
 558                 args.type = XFS_ALLOCTYPE_FIRST_AG;
 559                 args.minleft = 0;
 560                 error = xfs_alloc_vextent(&args);
 561                 if (error)
 562                         goto error0;
 563                 cur->bc_private.b.flist->xbf_low = 1;
 564         }
 565         if (args.fsbno == NULLFSBLOCK) {
 566                 XFS_BTREE_TRACE_CURSOR(cur, XBT_EXIT);
 567                 *stat = 0;
 568                 return 0;
 569         }
 570         ASSERT(args.len == 1);
 571         cur->bc_private.b.firstblock = args.fsbno;
 572         cur->bc_private.b.allocated++;
 573         cur->bc_private.b.ip->i_d.di_nblocks++;
 574         xfs_trans_log_inode(args.tp, cur->bc_private.b.ip, XFS_ILOG_CORE);
 575         xfs_trans_mod_dquot_byino(args.tp, cur->bc_private.b.ip,
 576                         XFS_TRANS_DQ_BCOUNT, 1L);
 577
 578         new->l = cpu_to_be64(args.fsbno);
 579
 580         XFS_BTREE_TRACE_CURSOR(cur, XBT_EXIT);
 581         *stat = 1;
 582         return 0;
 583
 584  error0:
 585         XFS_BTREE_TRACE_CURSOR(cur, XBT_ERROR);
 586         return error;
 587 }
 588
 589 STATIC int
 590 xfs_bmbt_free_block(
 591         struct xfs_btree_cur    *cur,
 592         struct xfs_buf          *bp)
 593 {
 594         struct xfs_mount        *mp = cur->bc_mp;
 595         struct xfs_inode        *ip = cur->bc_private.b.ip;
 596         struct xfs_trans        *tp = cur->bc_tp;
 597         xfs_fsblock_t           fsbno = XFS_DADDR_TO_FSB(mp, XFS_BUF_ADDR(bp));
 598
 599         xfs_bmap_add_free(fsbno, 1, cur->bc_private.b.flist, mp);
 600         ip->i_d.di_nblocks--;
 601
 602         xfs_trans_log_inode(tp, ip, XFS_ILOG_CORE);
 603         xfs_trans_mod_dquot_byino(tp, ip, XFS_TRANS_DQ_BCOUNT, -1L);
 604         xfs_trans_binval(tp, bp);
 605         return 0;
 606 }
 607
 608 STATIC int
 609 xfs_bmbt_get_minrecs(
 610         struct xfs_btree_cur    *cur,
 611         int                     level)
 612 {
 613         if (level == cur->bc_nlevels - 1) {
 614                 struct xfs_ifork        *ifp;
 615
 616                 ifp = XFS_IFORK_PTR(cur->bc_private.b.ip,
 617                                     cur->bc_private.b.whichfork);
 618
 619                 return xfs_bmbt_maxrecs(cur->bc_mp,
 620                                         ifp->if_broot_bytes, level == 0) / 2;
 621         }
 622
 623         return cur->bc_mp->m_bmap_dmnr[level != 0];
 624 }
 625
 626 int
 627 xfs_bmbt_get_maxrecs(
 628         struct xfs_btree_cur    *cur,
 629         int                     level)
 630 {
 631         if (level == cur->bc_nlevels - 1) {
 632                 struct xfs_ifork        *ifp;
 633
 634                 ifp = XFS_IFORK_PTR(cur->bc_private.b.ip,
 635                                     cur->bc_private.b.whichfork);
 636
 637                 return xfs_bmbt_maxrecs(cur->bc_mp,
 638                                         ifp->if_broot_bytes, level == 0);
 639         }
 640
 641         return cur->bc_mp->m_bmap_dmxr[level != 0];
 642
 643 }
 644
 645 /*
 646  * Get the maximum records we could store in the on-disk format.
 647  *
 648  * For non-root nodes this is equivalent to xfs_bmbt_get_maxrecs, but
 649  * for the root node this checks the available space in the dinode fork
 650  * so that we can resize the in-memory buffer to match it.  After a
 651  * resize to the maximum size this function returns the same value
 652  * as xfs_bmbt_get_maxrecs for the root node, too.
 653  */
 654 STATIC int
 655 xfs_bmbt_get_dmaxrecs(
 656         struct xfs_btree_cur    *cur,
 657         int                     level)
 658 {
 659         if (level != cur->bc_nlevels - 1)
 660                 return cur->bc_mp->m_bmap_dmxr[level != 0];
 661         return xfs_bmdr_maxrecs(cur->bc_mp, cur->bc_private.b.forksize,
 662                                 level == 0);
 663 }
 664
 665 STATIC void
 666 xfs_bmbt_init_key_from_rec(
 667         union xfs_btree_key     *key,
 668         union xfs_btree_rec     *rec)
 669 {
 670         key->bmbt.br_startoff =
 671                 cpu_to_be64(xfs_bmbt_disk_get_startoff(&rec->bmbt));
 672 }
 673
 674 STATIC void
 675 xfs_bmbt_init_rec_from_key(
 676         union xfs_btree_key     *key,
 677         union xfs_btree_rec     *rec)
 678 {
 679         ASSERT(key->bmbt.br_startoff != 0);
 680
 681         xfs_bmbt_disk_set_allf(&rec->bmbt, be64_to_cpu(key->bmbt.br_startoff),
 682                                0, 0, XFS_EXT_NORM);
 683 }
 684
 685 STATIC void
 686 xfs_bmbt_init_rec_from_cur(
 687         struct xfs_btree_cur    *cur,
 688         union xfs_btree_rec     *rec)
 689 {
 690         xfs_bmbt_disk_set_all(&rec->bmbt, &cur->bc_rec.b);
 691 }
 692
 693 STATIC void
 694 xfs_bmbt_init_ptr_from_cur(
 695         struct xfs_btree_cur    *cur,
 696         union xfs_btree_ptr     *ptr)
 697 {
 698         ptr->l = 0;
 699 }
 700
 701 STATIC __int64_t
 702 xfs_bmbt_key_diff(
 703         struct xfs_btree_cur    *cur,
 704         union xfs_btree_key     *key)
 705 {
 706         return (__int64_t)be64_to_cpu(key->bmbt.br_startoff) -
 707                                       cur->bc_rec.b.br_startoff;
 708 }
 709
 710 #ifdef DEBUG
 711 STATIC int
 712 xfs_bmbt_keys_inorder(
 713         struct xfs_btree_cur    *cur,
 714         union xfs_btree_key     *k1,
 715         union xfs_btree_key     *k2)
 716 {
 717         return be64_to_cpu(k1->bmbt.br_startoff) <
 718                 be64_to_cpu(k2->bmbt.br_startoff);
 719 }
 720
 721 STATIC int
 722 xfs_bmbt_recs_inorder(
 723         struct xfs_btree_cur    *cur,
 724         union xfs_btree_rec     *r1,
 725         union xfs_btree_rec     *r2)
 726 {
 727         return xfs_bmbt_disk_get_startoff(&r1->bmbt) +
 728                 xfs_bmbt_disk_get_blockcount(&r1->bmbt) <=
 729                 xfs_bmbt_disk_get_startoff(&r2->bmbt);
 730 }
 731 #endif  /* DEBUG */
 732
 733 static const struct xfs_btree_ops xfs_bmbt_ops = {
 734         .rec_len                = sizeof(xfs_bmbt_rec_t),
 735         .key_len                = sizeof(xfs_bmbt_key_t),
 736
 737         .dup_cursor             = xfs_bmbt_dup_cursor,
 738         .update_cursor          = xfs_bmbt_update_cursor,
 739         .alloc_block            = xfs_bmbt_alloc_block,
 740         .free_block             = xfs_bmbt_free_block,
 741         .get_maxrecs            = xfs_bmbt_get_maxrecs,
 742         .get_minrecs            = xfs_bmbt_get_minrecs,
 743         .get_dmaxrecs           = xfs_bmbt_get_dmaxrecs,
 744         .init_key_from_rec      = xfs_bmbt_init_key_from_rec,
 745         .init_rec_from_key      = xfs_bmbt_init_rec_from_key,
 746         .init_rec_from_cur      = xfs_bmbt_init_rec_from_cur,
 747         .init_ptr_from_cur      = xfs_bmbt_init_ptr_from_cur,
 748         .key_diff               = xfs_bmbt_key_diff,
 749 #ifdef DEBUG
 750         .keys_inorder           = xfs_bmbt_keys_inorder,
 751         .recs_inorder           = xfs_bmbt_recs_inorder,
 752 #endif
 753 };
 754
 755 /*
 756  * Allocate a new bmap btree cursor.
 757  */
 758 struct xfs_btree_cur *                          /* new bmap btree cursor */
 759 xfs_bmbt_init_cursor(
 760         struct xfs_mount        *mp,            /* file system mount point */
 761         struct xfs_trans        *tp,            /* transaction pointer */
 762         struct xfs_inode        *ip,            /* inode owning the btree */
 763         int                     whichfork)      /* data or attr fork */
 764 {
 765         struct xfs_ifork        *ifp = XFS_IFORK_PTR(ip, whichfork);
 766         struct xfs_btree_cur    *cur;
 767
 768         cur = kmem_zone_zalloc(xfs_btree_cur_zone, KM_SLEEP);
 769
 770         cur->bc_tp = tp;
 771         cur->bc_mp = mp;
 772         cur->bc_nlevels = be16_to_cpu(ifp->if_broot->bb_level) + 1;
 773         cur->bc_btnum = XFS_BTNUM_BMAP;
 774         cur->bc_blocklog = mp->m_sb.sb_blocklog;
 775
 776         cur->bc_ops = &xfs_bmbt_ops;
 777         cur->bc_flags = XFS_BTREE_LONG_PTRS | XFS_BTREE_ROOT_IN_INODE;
 778
 779         cur->bc_private.b.forksize = XFS_IFORK_SIZE(ip, whichfork);
 780         cur->bc_private.b.ip = ip;
 781         cur->bc_private.b.firstblock = NULLFSBLOCK;
 782         cur->bc_private.b.flist = NULL;
 783         cur->bc_private.b.allocated = 0;
 784         cur->bc_private.b.flags = 0;
 785         cur->bc_private.b.whichfork = whichfork;
 786
 787         return cur;
 788 }
 789
 790 /*
 791  * Calculate number of records in a bmap btree block.
 792  */
 793 int
 794 xfs_bmbt_maxrecs(
 795         struct xfs_mount        *mp,
 796         int                     blocklen,
 797         int                     leaf)
 798 {
 799         blocklen -= XFS_BMBT_BLOCK_LEN(mp);
 800
 801         if (leaf)
 802                 return blocklen / sizeof(xfs_bmbt_rec_t);
 803         return blocklen / (sizeof(xfs_bmbt_key_t) + sizeof(xfs_bmbt_ptr_t));
 804 }
 805
 806 /*
 807  * Calculate number of records in a bmap btree inode root.
 808  */
 809 int
 810 xfs_bmdr_maxrecs(
 811         struct xfs_mount        *mp,
 812         int                     blocklen,
 813         int                     leaf)
 814 {
 815         blocklen -= sizeof(xfs_bmdr_block_t);
 816
 817         if (leaf)
 818                 return blocklen / sizeof(xfs_bmdr_rec_t);
 819         return blocklen / (sizeof(xfs_bmdr_key_t) + sizeof(xfs_bmdr_ptr_t));
 820 }