fs/xfs/libxfs/xfs_bmap_btree.c

   1 // SPDX-License-Identifier: GPL-2.0
   2 /*
   3  * Copyright (c) 2000-2003,2005 Silicon Graphics, Inc.
   4  * All Rights Reserved.
   5  */
   6 #include "xfs.h"
   7 #include "xfs_fs.h"
   8 #include "xfs_shared.h"
   9 #include "xfs_format.h"
  10 #include "xfs_log_format.h"
  11 #include "xfs_trans_resv.h"
  12 #include "xfs_bit.h"
  13 #include "xfs_mount.h"
  14 #include "xfs_inode.h"
  15 #include "xfs_trans.h"
  16 #include "xfs_alloc.h"
  17 #include "xfs_btree.h"
  18 #include "xfs_bmap_btree.h"
  19 #include "xfs_bmap.h"
  20 #include "xfs_error.h"
  21 #include "xfs_quota.h"
  22 #include "xfs_trace.h"
  23 #include "xfs_rmap.h"
  24 #include "xfs_ag.h"
  25
  26 static struct kmem_cache        *xfs_bmbt_cur_cache;
  27
  28 /*
  29  * Convert on-disk form of btree root to in-memory form.
  30  */
  31 void
  32 xfs_bmdr_to_bmbt(
  33         struct xfs_inode        *ip,
  34         xfs_bmdr_block_t        *dblock,
  35         int                     dblocklen,
  36         struct xfs_btree_block  *rblock,
  37         int                     rblocklen)
  38 {
  39         struct xfs_mount        *mp = ip->i_mount;
  40         int                     dmxr;
  41         xfs_bmbt_key_t          *fkp;
  42         __be64                  *fpp;
  43         xfs_bmbt_key_t          *tkp;
  44         __be64                  *tpp;
  45
  46         xfs_btree_init_block_int(mp, rblock, XFS_BUF_DADDR_NULL,
  47                                  XFS_BTNUM_BMAP, 0, 0, ip->i_ino,
  48                                  XFS_BTREE_LONG_PTRS);
  49         rblock->bb_level = dblock->bb_level;
  50         ASSERT(be16_to_cpu(rblock->bb_level) > 0);
  51         rblock->bb_numrecs = dblock->bb_numrecs;
  52         dmxr = xfs_bmdr_maxrecs(dblocklen, 0);
  53         fkp = XFS_BMDR_KEY_ADDR(dblock, 1);
  54         tkp = XFS_BMBT_KEY_ADDR(mp, rblock, 1);
  55         fpp = XFS_BMDR_PTR_ADDR(dblock, 1, dmxr);
  56         tpp = XFS_BMAP_BROOT_PTR_ADDR(mp, rblock, 1, rblocklen);
  57         dmxr = be16_to_cpu(dblock->bb_numrecs);
  58         memcpy(tkp, fkp, sizeof(*fkp) * dmxr);
  59         memcpy(tpp, fpp, sizeof(*fpp) * dmxr);
  60 }
  61
  62 void
  63 xfs_bmbt_disk_get_all(
  64         const struct xfs_bmbt_rec *rec,
  65         struct xfs_bmbt_irec    *irec)
  66 {
  67         uint64_t                l0 = get_unaligned_be64(&rec->l0);
  68         uint64_t                l1 = get_unaligned_be64(&rec->l1);
  69
  70         irec->br_startoff = (l0 & xfs_mask64lo(64 - BMBT_EXNTFLAG_BITLEN)) >> 9;
  71         irec->br_startblock = ((l0 & xfs_mask64lo(9)) << 43) | (l1 >> 21);
  72         irec->br_blockcount = l1 & xfs_mask64lo(21);
  73         if (l0 >> (64 - BMBT_EXNTFLAG_BITLEN))
  74                 irec->br_state = XFS_EXT_UNWRITTEN;
  75         else
  76                 irec->br_state = XFS_EXT_NORM;
  77 }
  78
  79 /*
  80  * Extract the blockcount field from an on disk bmap extent record.
  81  */
  82 xfs_filblks_t
  83 xfs_bmbt_disk_get_blockcount(
  84         const struct xfs_bmbt_rec       *r)
  85 {
  86         return (xfs_filblks_t)(be64_to_cpu(r->l1) & xfs_mask64lo(21));
  87 }
  88
  89 /*
  90  * Extract the startoff field from a disk format bmap extent record.
  91  */
  92 xfs_fileoff_t
  93 xfs_bmbt_disk_get_startoff(
  94         const struct xfs_bmbt_rec       *r)
  95 {
  96         return ((xfs_fileoff_t)be64_to_cpu(r->l0) &
  97                  xfs_mask64lo(64 - BMBT_EXNTFLAG_BITLEN)) >> 9;
  98 }
  99
 100 /*
 101  * Set all the fields in a bmap extent record from the uncompressed form.
 102  */
 103 void
 104 xfs_bmbt_disk_set_all(
 105         struct xfs_bmbt_rec     *r,
 106         struct xfs_bmbt_irec    *s)
 107 {
 108         int                     extent_flag = (s->br_state != XFS_EXT_NORM);
 109
 110         ASSERT(s->br_state == XFS_EXT_NORM || s->br_state == XFS_EXT_UNWRITTEN);
 111         ASSERT(!(s->br_startoff & xfs_mask64hi(64-BMBT_STARTOFF_BITLEN)));
 112         ASSERT(!(s->br_blockcount & xfs_mask64hi(64-BMBT_BLOCKCOUNT_BITLEN)));
 113         ASSERT(!(s->br_startblock & xfs_mask64hi(64-BMBT_STARTBLOCK_BITLEN)));
 114
 115         put_unaligned_be64(
 116                 ((xfs_bmbt_rec_base_t)extent_flag << 63) |
 117                  ((xfs_bmbt_rec_base_t)s->br_startoff << 9) |
 118                  ((xfs_bmbt_rec_base_t)s->br_startblock >> 43), &r->l0);
 119         put_unaligned_be64(
 120                 ((xfs_bmbt_rec_base_t)s->br_startblock << 21) |
 121                  ((xfs_bmbt_rec_base_t)s->br_blockcount &
 122                   (xfs_bmbt_rec_base_t)xfs_mask64lo(21)), &r->l1);
 123 }
 124
 125 /*
 126  * Convert in-memory form of btree root to on-disk form.
 127  */
 128 void
 129 xfs_bmbt_to_bmdr(
 130         struct xfs_mount        *mp,
 131         struct xfs_btree_block  *rblock,
 132         int                     rblocklen,
 133         xfs_bmdr_block_t        *dblock,
 134         int                     dblocklen)
 135 {
 136         int                     dmxr;
 137         xfs_bmbt_key_t          *fkp;
 138         __be64                  *fpp;
 139         xfs_bmbt_key_t          *tkp;
 140         __be64                  *tpp;
 141
 142         if (xfs_has_crc(mp)) {
 143                 ASSERT(rblock->bb_magic == cpu_to_be32(XFS_BMAP_CRC_MAGIC));
 144                 ASSERT(uuid_equal(&rblock->bb_u.l.bb_uuid,
 145                        &mp->m_sb.sb_meta_uuid));
 146                 ASSERT(rblock->bb_u.l.bb_blkno ==
 147                        cpu_to_be64(XFS_BUF_DADDR_NULL));
 148         } else
 149                 ASSERT(rblock->bb_magic == cpu_to_be32(XFS_BMAP_MAGIC));
 150         ASSERT(rblock->bb_u.l.bb_leftsib == cpu_to_be64(NULLFSBLOCK));
 151         ASSERT(rblock->bb_u.l.bb_rightsib == cpu_to_be64(NULLFSBLOCK));
 152         ASSERT(rblock->bb_level != 0);
 153         dblock->bb_level = rblock->bb_level;
 154         dblock->bb_numrecs = rblock->bb_numrecs;
 155         dmxr = xfs_bmdr_maxrecs(dblocklen, 0);
 156         fkp = XFS_BMBT_KEY_ADDR(mp, rblock, 1);
 157         tkp = XFS_BMDR_KEY_ADDR(dblock, 1);
 158         fpp = XFS_BMAP_BROOT_PTR_ADDR(mp, rblock, 1, rblocklen);
 159         tpp = XFS_BMDR_PTR_ADDR(dblock, 1, dmxr);
 160         dmxr = be16_to_cpu(dblock->bb_numrecs);
 161         memcpy(tkp, fkp, sizeof(*fkp) * dmxr);
 162         memcpy(tpp, fpp, sizeof(*fpp) * dmxr);
 163 }
 164
 165 STATIC struct xfs_btree_cur *
 166 xfs_bmbt_dup_cursor(
 167         struct xfs_btree_cur    *cur)
 168 {
 169         struct xfs_btree_cur    *new;
 170
 171         new = xfs_bmbt_init_cursor(cur->bc_mp, cur->bc_tp,
 172                         cur->bc_ino.ip, cur->bc_ino.whichfork);
 173
 174         /*
 175          * Copy the firstblock, dfops, and flags values,
 176          * since init cursor doesn't get them.
 177          */
 178         new->bc_ino.flags = cur->bc_ino.flags;
 179
 180         return new;
 181 }
 182
 183 STATIC void
 184 xfs_bmbt_update_cursor(
 185         struct xfs_btree_cur    *src,
 186         struct xfs_btree_cur    *dst)
 187 {
 188         ASSERT((dst->bc_tp->t_highest_agno != NULLAGNUMBER) ||
 189                (dst->bc_ino.ip->i_diflags & XFS_DIFLAG_REALTIME));
 190
 191         dst->bc_ino.allocated += src->bc_ino.allocated;
 192         dst->bc_tp->t_highest_agno = src->bc_tp->t_highest_agno;
 193
 194         src->bc_ino.allocated = 0;
 195 }
 196
 197 STATIC int
 198 xfs_bmbt_alloc_block(
 199         struct xfs_btree_cur            *cur,
 200         const union xfs_btree_ptr       *start,
 201         union xfs_btree_ptr             *new,
 202         int                             *stat)
 203 {
 204         struct xfs_alloc_arg    args;
 205         int                     error;
 206
 207         memset(&args, 0, sizeof(args));
 208         args.tp = cur->bc_tp;
 209         args.mp = cur->bc_mp;
 210         xfs_rmap_ino_bmbt_owner(&args.oinfo, cur->bc_ino.ip->i_ino,
 211                         cur->bc_ino.whichfork);
 212         args.minlen = args.maxlen = args.prod = 1;
 213         args.wasdel = cur->bc_ino.flags & XFS_BTCUR_BMBT_WASDEL;
 214         if (!args.wasdel && args.tp->t_blk_res == 0)
 215                 return -ENOSPC;
 216
 217         /*
 218          * If we are coming here from something like unwritten extent
 219          * conversion, there has been no data extent allocation already done, so
 220          * we have to ensure that we attempt to locate the entire set of bmbt
 221          * allocations in the same AG, as xfs_bmapi_write() would have reserved.
 222          */
 223         if (cur->bc_tp->t_highest_agno == NULLAGNUMBER)
 224                 args.minleft = xfs_bmapi_minleft(cur->bc_tp, cur->bc_ino.ip,
 225                                         cur->bc_ino.whichfork);
 226
 227         error = xfs_alloc_vextent_start_ag(&args, be64_to_cpu(start->l));
 228         if (error)
 229                 return error;
 230
 231         if (args.fsbno == NULLFSBLOCK && args.minleft) {
 232                 /*
 233                  * Could not find an AG with enough free space to satisfy
 234                  * a full btree split.  Try again and if
 235                  * successful activate the lowspace algorithm.
 236                  */
 237                 args.minleft = 0;
 238                 error = xfs_alloc_vextent_start_ag(&args, 0);
 239                 if (error)
 240                         return error;
 241                 cur->bc_tp->t_flags |= XFS_TRANS_LOWMODE;
 242         }
 243         if (WARN_ON_ONCE(args.fsbno == NULLFSBLOCK)) {
 244                 *stat = 0;
 245                 return 0;
 246         }
 247
 248         ASSERT(args.len == 1);
 249         cur->bc_ino.allocated++;
 250         cur->bc_ino.ip->i_nblocks++;
 251         xfs_trans_log_inode(args.tp, cur->bc_ino.ip, XFS_ILOG_CORE);
 252         xfs_trans_mod_dquot_byino(args.tp, cur->bc_ino.ip,
 253                         XFS_TRANS_DQ_BCOUNT, 1L);
 254
 255         new->l = cpu_to_be64(args.fsbno);
 256
 257         *stat = 1;
 258         return 0;
 259 }
 260
 261 STATIC int
 262 xfs_bmbt_free_block(
 263         struct xfs_btree_cur    *cur,
 264         struct xfs_buf          *bp)
 265 {
 266         struct xfs_mount        *mp = cur->bc_mp;
 267         struct xfs_inode        *ip = cur->bc_ino.ip;
 268         struct xfs_trans        *tp = cur->bc_tp;
 269         xfs_fsblock_t           fsbno = XFS_DADDR_TO_FSB(mp, xfs_buf_daddr(bp));
 270         struct xfs_owner_info   oinfo;
 271         int                     error;
 272
 273         xfs_rmap_ino_bmbt_owner(&oinfo, ip->i_ino, cur->bc_ino.whichfork);
 274         error = xfs_free_extent_later(cur->bc_tp, fsbno, 1, &oinfo,
 275                         XFS_AG_RESV_NONE);
 276         if (error)
 277                 return error;
 278
 279         ip->i_nblocks--;
 280         xfs_trans_log_inode(tp, ip, XFS_ILOG_CORE);
 281         xfs_trans_mod_dquot_byino(tp, ip, XFS_TRANS_DQ_BCOUNT, -1L);
 282         return 0;
 283 }
 284
 285 STATIC int
 286 xfs_bmbt_get_minrecs(
 287         struct xfs_btree_cur    *cur,
 288         int                     level)
 289 {
 290         if (level == cur->bc_nlevels - 1) {
 291                 struct xfs_ifork        *ifp;
 292
 293                 ifp = xfs_ifork_ptr(cur->bc_ino.ip,
 294                                     cur->bc_ino.whichfork);
 295
 296                 return xfs_bmbt_maxrecs(cur->bc_mp,
 297                                         ifp->if_broot_bytes, level == 0) / 2;
 298         }
 299
 300         return cur->bc_mp->m_bmap_dmnr[level != 0];
 301 }
 302
 303 int
 304 xfs_bmbt_get_maxrecs(
 305         struct xfs_btree_cur    *cur,
 306         int                     level)
 307 {
 308         if (level == cur->bc_nlevels - 1) {
 309                 struct xfs_ifork        *ifp;
 310
 311                 ifp = xfs_ifork_ptr(cur->bc_ino.ip,
 312                                     cur->bc_ino.whichfork);
 313
 314                 return xfs_bmbt_maxrecs(cur->bc_mp,
 315                                         ifp->if_broot_bytes, level == 0);
 316         }
 317
 318         return cur->bc_mp->m_bmap_dmxr[level != 0];
 319
 320 }
 321
 322 /*
 323  * Get the maximum records we could store in the on-disk format.
 324  *
 325  * For non-root nodes this is equivalent to xfs_bmbt_get_maxrecs, but
 326  * for the root node this checks the available space in the dinode fork
 327  * so that we can resize the in-memory buffer to match it.  After a
 328  * resize to the maximum size this function returns the same value
 329  * as xfs_bmbt_get_maxrecs for the root node, too.
 330  */
 331 STATIC int
 332 xfs_bmbt_get_dmaxrecs(
 333         struct xfs_btree_cur    *cur,
 334         int                     level)
 335 {
 336         if (level != cur->bc_nlevels - 1)
 337                 return cur->bc_mp->m_bmap_dmxr[level != 0];
 338         return xfs_bmdr_maxrecs(cur->bc_ino.forksize, level == 0);
 339 }
 340
 341 STATIC void
 342 xfs_bmbt_init_key_from_rec(
 343         union xfs_btree_key             *key,
 344         const union xfs_btree_rec       *rec)
 345 {
 346         key->bmbt.br_startoff =
 347                 cpu_to_be64(xfs_bmbt_disk_get_startoff(&rec->bmbt));
 348 }
 349
 350 STATIC void
 351 xfs_bmbt_init_high_key_from_rec(
 352         union xfs_btree_key             *key,
 353         const union xfs_btree_rec       *rec)
 354 {
 355         key->bmbt.br_startoff = cpu_to_be64(
 356                         xfs_bmbt_disk_get_startoff(&rec->bmbt) +
 357                         xfs_bmbt_disk_get_blockcount(&rec->bmbt) - 1);
 358 }
 359
 360 STATIC void
 361 xfs_bmbt_init_rec_from_cur(
 362         struct xfs_btree_cur    *cur,
 363         union xfs_btree_rec     *rec)
 364 {
 365         xfs_bmbt_disk_set_all(&rec->bmbt, &cur->bc_rec.b);
 366 }
 367
 368 STATIC void
 369 xfs_bmbt_init_ptr_from_cur(
 370         struct xfs_btree_cur    *cur,
 371         union xfs_btree_ptr     *ptr)
 372 {
 373         ptr->l = 0;
 374 }
 375
 376 STATIC int64_t
 377 xfs_bmbt_key_diff(
 378         struct xfs_btree_cur            *cur,
 379         const union xfs_btree_key       *key)
 380 {
 381         return (int64_t)be64_to_cpu(key->bmbt.br_startoff) -
 382                                       cur->bc_rec.b.br_startoff;
 383 }
 384
 385 STATIC int64_t
 386 xfs_bmbt_diff_two_keys(
 387         struct xfs_btree_cur            *cur,
 388         const union xfs_btree_key       *k1,
 389         const union xfs_btree_key       *k2,
 390         const union xfs_btree_key       *mask)
 391 {
 392         uint64_t                        a = be64_to_cpu(k1->bmbt.br_startoff);
 393         uint64_t                        b = be64_to_cpu(k2->bmbt.br_startoff);
 394
 395         ASSERT(!mask || mask->bmbt.br_startoff);
 396
 397         /*
 398          * Note: This routine previously casted a and b to int64 and subtracted
 399          * them to generate a result.  This lead to problems if b was the
 400          * "maximum" key value (all ones) being signed incorrectly, hence this
 401          * somewhat less efficient version.
 402          */
 403         if (a > b)
 404                 return 1;
 405         if (b > a)
 406                 return -1;
 407         return 0;
 408 }
 409
 410 static xfs_failaddr_t
 411 xfs_bmbt_verify(
 412         struct xfs_buf          *bp)
 413 {
 414         struct xfs_mount        *mp = bp->b_mount;
 415         struct xfs_btree_block  *block = XFS_BUF_TO_BLOCK(bp);
 416         xfs_failaddr_t          fa;
 417         unsigned int            level;
 418
 419         if (!xfs_verify_magic(bp, block->bb_magic))
 420                 return __this_address;
 421
 422         if (xfs_has_crc(mp)) {
 423                 /*
 424                  * XXX: need a better way of verifying the owner here. Right now
 425                  * just make sure there has been one set.
 426                  */
 427                 fa = xfs_btree_lblock_v5hdr_verify(bp, XFS_RMAP_OWN_UNKNOWN);
 428                 if (fa)
 429                         return fa;
 430         }
 431
 432         /*
 433          * numrecs and level verification.
 434          *
 435          * We don't know what fork we belong to, so just verify that the level
 436          * is less than the maximum of the two. Later checks will be more
 437          * precise.
 438          */
 439         level = be16_to_cpu(block->bb_level);
 440         if (level > max(mp->m_bm_maxlevels[0], mp->m_bm_maxlevels[1]))
 441                 return __this_address;
 442
 443         return xfs_btree_lblock_verify(bp, mp->m_bmap_dmxr[level != 0]);
 444 }
 445
 446 static void
 447 xfs_bmbt_read_verify(
 448         struct xfs_buf  *bp)
 449 {
 450         xfs_failaddr_t  fa;
 451
 452         if (!xfs_btree_lblock_verify_crc(bp))
 453                 xfs_verifier_error(bp, -EFSBADCRC, __this_address);
 454         else {
 455                 fa = xfs_bmbt_verify(bp);
 456                 if (fa)
 457                         xfs_verifier_error(bp, -EFSCORRUPTED, fa);
 458         }
 459
 460         if (bp->b_error)
 461                 trace_xfs_btree_corrupt(bp, _RET_IP_);
 462 }
 463
 464 static void
 465 xfs_bmbt_write_verify(
 466         struct xfs_buf  *bp)
 467 {
 468         xfs_failaddr_t  fa;
 469
 470         fa = xfs_bmbt_verify(bp);
 471         if (fa) {
 472                 trace_xfs_btree_corrupt(bp, _RET_IP_);
 473                 xfs_verifier_error(bp, -EFSCORRUPTED, fa);
 474                 return;
 475         }
 476         xfs_btree_lblock_calc_crc(bp);
 477 }
 478
 479 const struct xfs_buf_ops xfs_bmbt_buf_ops = {
 480         .name = "xfs_bmbt",
 481         .magic = { cpu_to_be32(XFS_BMAP_MAGIC),
 482                    cpu_to_be32(XFS_BMAP_CRC_MAGIC) },
 483         .verify_read = xfs_bmbt_read_verify,
 484         .verify_write = xfs_bmbt_write_verify,
 485         .verify_struct = xfs_bmbt_verify,
 486 };
 487
 488
 489 STATIC int
 490 xfs_bmbt_keys_inorder(
 491         struct xfs_btree_cur            *cur,
 492         const union xfs_btree_key       *k1,
 493         const union xfs_btree_key       *k2)
 494 {
 495         return be64_to_cpu(k1->bmbt.br_startoff) <
 496                 be64_to_cpu(k2->bmbt.br_startoff);
 497 }
 498
 499 STATIC int
 500 xfs_bmbt_recs_inorder(
 501         struct xfs_btree_cur            *cur,
 502         const union xfs_btree_rec       *r1,
 503         const union xfs_btree_rec       *r2)
 504 {
 505         return xfs_bmbt_disk_get_startoff(&r1->bmbt) +
 506                 xfs_bmbt_disk_get_blockcount(&r1->bmbt) <=
 507                 xfs_bmbt_disk_get_startoff(&r2->bmbt);
 508 }
 509
 510 STATIC enum xbtree_key_contig
 511 xfs_bmbt_keys_contiguous(
 512         struct xfs_btree_cur            *cur,
 513         const union xfs_btree_key       *key1,
 514         const union xfs_btree_key       *key2,
 515         const union xfs_btree_key       *mask)
 516 {
 517         ASSERT(!mask || mask->bmbt.br_startoff);
 518
 519         return xbtree_key_contig(be64_to_cpu(key1->bmbt.br_startoff),
 520                                  be64_to_cpu(key2->bmbt.br_startoff));
 521 }
 522
 523 static const struct xfs_btree_ops xfs_bmbt_ops = {
 524         .rec_len                = sizeof(xfs_bmbt_rec_t),
 525         .key_len                = sizeof(xfs_bmbt_key_t),
 526
 527         .dup_cursor             = xfs_bmbt_dup_cursor,
 528         .update_cursor          = xfs_bmbt_update_cursor,
 529         .alloc_block            = xfs_bmbt_alloc_block,
 530         .free_block             = xfs_bmbt_free_block,
 531         .get_maxrecs            = xfs_bmbt_get_maxrecs,
 532         .get_minrecs            = xfs_bmbt_get_minrecs,
 533         .get_dmaxrecs           = xfs_bmbt_get_dmaxrecs,
 534         .init_key_from_rec      = xfs_bmbt_init_key_from_rec,
 535         .init_high_key_from_rec = xfs_bmbt_init_high_key_from_rec,
 536         .init_rec_from_cur      = xfs_bmbt_init_rec_from_cur,
 537         .init_ptr_from_cur      = xfs_bmbt_init_ptr_from_cur,
 538         .key_diff               = xfs_bmbt_key_diff,
 539         .diff_two_keys          = xfs_bmbt_diff_two_keys,
 540         .buf_ops                = &xfs_bmbt_buf_ops,
 541         .keys_inorder           = xfs_bmbt_keys_inorder,
 542         .recs_inorder           = xfs_bmbt_recs_inorder,
 543         .keys_contiguous        = xfs_bmbt_keys_contiguous,
 544 };
 545
 546 /*
 547  * Allocate a new bmap btree cursor.
 548  */
 549 struct xfs_btree_cur *                          /* new bmap btree cursor */
 550 xfs_bmbt_init_cursor(
 551         struct xfs_mount        *mp,            /* file system mount point */
 552         struct xfs_trans        *tp,            /* transaction pointer */
 553         struct xfs_inode        *ip,            /* inode owning the btree */
 554         int                     whichfork)      /* data or attr fork */
 555 {
 556         struct xfs_ifork        *ifp = xfs_ifork_ptr(ip, whichfork);
 557         struct xfs_btree_cur    *cur;
 558         ASSERT(whichfork != XFS_COW_FORK);
 559
 560         cur = xfs_btree_alloc_cursor(mp, tp, XFS_BTNUM_BMAP,
 561                         mp->m_bm_maxlevels[whichfork], xfs_bmbt_cur_cache);
 562         cur->bc_nlevels = be16_to_cpu(ifp->if_broot->bb_level) + 1;
 563         cur->bc_statoff = XFS_STATS_CALC_INDEX(xs_bmbt_2);
 564
 565         cur->bc_ops = &xfs_bmbt_ops;
 566         cur->bc_flags = XFS_BTREE_LONG_PTRS | XFS_BTREE_ROOT_IN_INODE;
 567         if (xfs_has_crc(mp))
 568                 cur->bc_flags |= XFS_BTREE_CRC_BLOCKS;
 569
 570         cur->bc_ino.forksize = xfs_inode_fork_size(ip, whichfork);
 571         cur->bc_ino.ip = ip;
 572         cur->bc_ino.allocated = 0;
 573         cur->bc_ino.flags = 0;
 574         cur->bc_ino.whichfork = whichfork;
 575
 576         return cur;
 577 }
 578
 579 /* Calculate number of records in a block mapping btree block. */
 580 static inline unsigned int
 581 xfs_bmbt_block_maxrecs(
 582         unsigned int            blocklen,
 583         bool                    leaf)
 584 {
 585         if (leaf)
 586                 return blocklen / sizeof(xfs_bmbt_rec_t);
 587         return blocklen / (sizeof(xfs_bmbt_key_t) + sizeof(xfs_bmbt_ptr_t));
 588 }
 589
 590 /*
 591  * Calculate number of records in a bmap btree block.
 592  */
 593 int
 594 xfs_bmbt_maxrecs(
 595         struct xfs_mount        *mp,
 596         int                     blocklen,
 597         int                     leaf)
 598 {
 599         blocklen -= XFS_BMBT_BLOCK_LEN(mp);
 600         return xfs_bmbt_block_maxrecs(blocklen, leaf);
 601 }
 602
 603 /*
 604  * Calculate the maximum possible height of the btree that the on-disk format
 605  * supports. This is used for sizing structures large enough to support every
 606  * possible configuration of a filesystem that might get mounted.
 607  */
 608 unsigned int
 609 xfs_bmbt_maxlevels_ondisk(void)
 610 {
 611         unsigned int            minrecs[2];
 612         unsigned int            blocklen;
 613
 614         blocklen = min(XFS_MIN_BLOCKSIZE - XFS_BTREE_SBLOCK_LEN,
 615                        XFS_MIN_CRC_BLOCKSIZE - XFS_BTREE_SBLOCK_CRC_LEN);
 616
 617         minrecs[0] = xfs_bmbt_block_maxrecs(blocklen, true) / 2;
 618         minrecs[1] = xfs_bmbt_block_maxrecs(blocklen, false) / 2;
 619
 620         /* One extra level for the inode root. */
 621         return xfs_btree_compute_maxlevels(minrecs,
 622                         XFS_MAX_EXTCNT_DATA_FORK_LARGE) + 1;
 623 }
 624
 625 /*
 626  * Calculate number of records in a bmap btree inode root.
 627  */
 628 int
 629 xfs_bmdr_maxrecs(
 630         int                     blocklen,
 631         int                     leaf)
 632 {
 633         blocklen -= sizeof(xfs_bmdr_block_t);
 634
 635         if (leaf)
 636                 return blocklen / sizeof(xfs_bmdr_rec_t);
 637         return blocklen / (sizeof(xfs_bmdr_key_t) + sizeof(xfs_bmdr_ptr_t));
 638 }
 639
 640 /*
 641  * Change the owner of a btree format fork fo the inode passed in. Change it to
 642  * the owner of that is passed in so that we can change owners before or after
 643  * we switch forks between inodes. The operation that the caller is doing will
 644  * determine whether is needs to change owner before or after the switch.
 645  *
 646  * For demand paged transactional modification, the fork switch should be done
 647  * after reading in all the blocks, modifying them and pinning them in the
 648  * transaction. For modification when the buffers are already pinned in memory,
 649  * the fork switch can be done before changing the owner as we won't need to
 650  * validate the owner until the btree buffers are unpinned and writes can occur
 651  * again.
 652  *
 653  * For recovery based ownership change, there is no transactional context and
 654  * so a buffer list must be supplied so that we can record the buffers that we
 655  * modified for the caller to issue IO on.
 656  */
 657 int
 658 xfs_bmbt_change_owner(
 659         struct xfs_trans        *tp,
 660         struct xfs_inode        *ip,
 661         int                     whichfork,
 662         xfs_ino_t               new_owner,
 663         struct list_head        *buffer_list)
 664 {
 665         struct xfs_btree_cur    *cur;
 666         int                     error;
 667
 668         ASSERT(tp || buffer_list);
 669         ASSERT(!(tp && buffer_list));
 670         ASSERT(xfs_ifork_ptr(ip, whichfork)->if_format == XFS_DINODE_FMT_BTREE);
 671
 672         cur = xfs_bmbt_init_cursor(ip->i_mount, tp, ip, whichfork);
 673         cur->bc_ino.flags |= XFS_BTCUR_BMBT_INVALID_OWNER;
 674
 675         error = xfs_btree_change_owner(cur, new_owner, buffer_list);
 676         xfs_btree_del_cursor(cur, error);
 677         return error;
 678 }
 679
 680 /* Calculate the bmap btree size for some records. */
 681 unsigned long long
 682 xfs_bmbt_calc_size(
 683         struct xfs_mount        *mp,
 684         unsigned long long      len)
 685 {
 686         return xfs_btree_calc_size(mp->m_bmap_dmnr, len);
 687 }
 688
 689 int __init
 690 xfs_bmbt_init_cur_cache(void)
 691 {
 692         xfs_bmbt_cur_cache = kmem_cache_create("xfs_bmbt_cur",
 693                         xfs_btree_cur_sizeof(xfs_bmbt_maxlevels_ondisk()),
 694                         0, 0, NULL);
 695
 696         if (!xfs_bmbt_cur_cache)
 697                 return -ENOMEM;
 698         return 0;
 699 }
 700
 701 void
 702 xfs_bmbt_destroy_cur_cache(void)
 703 {
 704         kmem_cache_destroy(xfs_bmbt_cur_cache);
 705         xfs_bmbt_cur_cache = NULL;
 706 }