fs/xfs/libxfs/xfs_da_btree.c

   1 // SPDX-License-Identifier: GPL-2.0
   2 /*
   3  * Copyright (c) 2000-2005 Silicon Graphics, Inc.
   4  * Copyright (c) 2013 Red Hat, Inc.
   5  * All Rights Reserved.
   6  */
   7 #include "xfs.h"
   8 #include "xfs_fs.h"
   9 #include "xfs_shared.h"
  10 #include "xfs_format.h"
  11 #include "xfs_log_format.h"
  12 #include "xfs_trans_resv.h"
  13 #include "xfs_bit.h"
  14 #include "xfs_mount.h"
  15 #include "xfs_da_format.h"
  16 #include "xfs_da_btree.h"
  17 #include "xfs_dir2.h"
  18 #include "xfs_dir2_priv.h"
  19 #include "xfs_inode.h"
  20 #include "xfs_trans.h"
  21 #include "xfs_inode_item.h"
  22 #include "xfs_alloc.h"
  23 #include "xfs_bmap.h"
  24 #include "xfs_attr.h"
  25 #include "xfs_attr_leaf.h"
  26 #include "xfs_error.h"
  27 #include "xfs_trace.h"
  28 #include "xfs_cksum.h"
  29 #include "xfs_buf_item.h"
  30 #include "xfs_log.h"
  31
  32 /*
  33  * xfs_da_btree.c
  34  *
  35  * Routines to implement directories as Btrees of hashed names.
  36  */
  37
  38 /*========================================================================
  39  * Function prototypes for the kernel.
  40  *========================================================================*/
  41
  42 /*
  43  * Routines used for growing the Btree.
  44  */
  45 STATIC int xfs_da3_root_split(xfs_da_state_t *state,
  46                                             xfs_da_state_blk_t *existing_root,
  47                                             xfs_da_state_blk_t *new_child);
  48 STATIC int xfs_da3_node_split(xfs_da_state_t *state,
  49                                             xfs_da_state_blk_t *existing_blk,
  50                                             xfs_da_state_blk_t *split_blk,
  51                                             xfs_da_state_blk_t *blk_to_add,
  52                                             int treelevel,
  53                                             int *result);
  54 STATIC void xfs_da3_node_rebalance(xfs_da_state_t *state,
  55                                          xfs_da_state_blk_t *node_blk_1,
  56                                          xfs_da_state_blk_t *node_blk_2);
  57 STATIC void xfs_da3_node_add(xfs_da_state_t *state,
  58                                    xfs_da_state_blk_t *old_node_blk,
  59                                    xfs_da_state_blk_t *new_node_blk);
  60
  61 /*
  62  * Routines used for shrinking the Btree.
  63  */
  64 STATIC int xfs_da3_root_join(xfs_da_state_t *state,
  65                                            xfs_da_state_blk_t *root_blk);
  66 STATIC int xfs_da3_node_toosmall(xfs_da_state_t *state, int *retval);
  67 STATIC void xfs_da3_node_remove(xfs_da_state_t *state,
  68                                               xfs_da_state_blk_t *drop_blk);
  69 STATIC void xfs_da3_node_unbalance(xfs_da_state_t *state,
  70                                          xfs_da_state_blk_t *src_node_blk,
  71                                          xfs_da_state_blk_t *dst_node_blk);
  72
  73 /*
  74  * Utility routines.
  75  */
  76 STATIC int      xfs_da3_blk_unlink(xfs_da_state_t *state,
  77                                   xfs_da_state_blk_t *drop_blk,
  78                                   xfs_da_state_blk_t *save_blk);
  79
  80
  81 kmem_zone_t *xfs_da_state_zone; /* anchor for state struct zone */
  82
  83 /*
  84  * Allocate a dir-state structure.
  85  * We don't put them on the stack since they're large.
  86  */
  87 xfs_da_state_t *
  88 xfs_da_state_alloc(void)
  89 {
  90         return kmem_zone_zalloc(xfs_da_state_zone, KM_NOFS);
  91 }
  92
  93 /*
  94  * Kill the altpath contents of a da-state structure.
  95  */
  96 STATIC void
  97 xfs_da_state_kill_altpath(xfs_da_state_t *state)
  98 {
  99         int     i;
 100
 101         for (i = 0; i < state->altpath.active; i++)
 102                 state->altpath.blk[i].bp = NULL;
 103         state->altpath.active = 0;
 104 }
 105
 106 /*
 107  * Free a da-state structure.
 108  */
 109 void
 110 xfs_da_state_free(xfs_da_state_t *state)
 111 {
 112         xfs_da_state_kill_altpath(state);
 113 #ifdef DEBUG
 114         memset((char *)state, 0, sizeof(*state));
 115 #endif /* DEBUG */
 116         kmem_zone_free(xfs_da_state_zone, state);
 117 }
 118
 119 static xfs_failaddr_t
 120 xfs_da3_node_verify(
 121         struct xfs_buf          *bp)
 122 {
 123         struct xfs_mount        *mp = bp->b_target->bt_mount;
 124         struct xfs_da_intnode   *hdr = bp->b_addr;
 125         struct xfs_da3_icnode_hdr ichdr;
 126         const struct xfs_dir_ops *ops;
 127
 128         ops = xfs_dir_get_ops(mp, NULL);
 129
 130         ops->node_hdr_from_disk(&ichdr, hdr);
 131
 132         if (xfs_sb_version_hascrc(&mp->m_sb)) {
 133                 struct xfs_da3_node_hdr *hdr3 = bp->b_addr;
 134
 135                 if (ichdr.magic != XFS_DA3_NODE_MAGIC)
 136                         return __this_address;
 137
 138                 if (!uuid_equal(&hdr3->info.uuid, &mp->m_sb.sb_meta_uuid))
 139                         return __this_address;
 140                 if (be64_to_cpu(hdr3->info.blkno) != bp->b_bn)
 141                         return __this_address;
 142                 if (!xfs_log_check_lsn(mp, be64_to_cpu(hdr3->info.lsn)))
 143                         return __this_address;
 144         } else {
 145                 if (ichdr.magic != XFS_DA_NODE_MAGIC)
 146                         return __this_address;
 147         }
 148         if (ichdr.level == 0)
 149                 return __this_address;
 150         if (ichdr.level > XFS_DA_NODE_MAXDEPTH)
 151                 return __this_address;
 152         if (ichdr.count == 0)
 153                 return __this_address;
 154
 155         /*
 156          * we don't know if the node is for and attribute or directory tree,
 157          * so only fail if the count is outside both bounds
 158          */
 159         if (ichdr.count > mp->m_dir_geo->node_ents &&
 160             ichdr.count > mp->m_attr_geo->node_ents)
 161                 return __this_address;
 162
 163         /* XXX: hash order check? */
 164
 165         return NULL;
 166 }
 167
 168 static void
 169 xfs_da3_node_write_verify(
 170         struct xfs_buf  *bp)
 171 {
 172         struct xfs_mount        *mp = bp->b_target->bt_mount;
 173         struct xfs_buf_log_item *bip = bp->b_log_item;
 174         struct xfs_da3_node_hdr *hdr3 = bp->b_addr;
 175         xfs_failaddr_t          fa;
 176
 177         fa = xfs_da3_node_verify(bp);
 178         if (fa) {
 179                 xfs_verifier_error(bp, -EFSCORRUPTED, fa);
 180                 return;
 181         }
 182
 183         if (!xfs_sb_version_hascrc(&mp->m_sb))
 184                 return;
 185
 186         if (bip)
 187                 hdr3->info.lsn = cpu_to_be64(bip->bli_item.li_lsn);
 188
 189         xfs_buf_update_cksum(bp, XFS_DA3_NODE_CRC_OFF);
 190 }
 191
 192 /*
 193  * leaf/node format detection on trees is sketchy, so a node read can be done on
 194  * leaf level blocks when detection identifies the tree as a node format tree
 195  * incorrectly. In this case, we need to swap the verifier to match the correct
 196  * format of the block being read.
 197  */
 198 static void
 199 xfs_da3_node_read_verify(
 200         struct xfs_buf          *bp)
 201 {
 202         struct xfs_da_blkinfo   *info = bp->b_addr;
 203         xfs_failaddr_t          fa;
 204
 205         switch (be16_to_cpu(info->magic)) {
 206                 case XFS_DA3_NODE_MAGIC:
 207                         if (!xfs_buf_verify_cksum(bp, XFS_DA3_NODE_CRC_OFF)) {
 208                                 xfs_verifier_error(bp, -EFSBADCRC,
 209                                                 __this_address);
 210                                 break;
 211                         }
 212                         /* fall through */
 213                 case XFS_DA_NODE_MAGIC:
 214                         fa = xfs_da3_node_verify(bp);
 215                         if (fa)
 216                                 xfs_verifier_error(bp, -EFSCORRUPTED, fa);
 217                         return;
 218                 case XFS_ATTR_LEAF_MAGIC:
 219                 case XFS_ATTR3_LEAF_MAGIC:
 220                         bp->b_ops = &xfs_attr3_leaf_buf_ops;
 221                         bp->b_ops->verify_read(bp);
 222                         return;
 223                 case XFS_DIR2_LEAFN_MAGIC:
 224                 case XFS_DIR3_LEAFN_MAGIC:
 225                         bp->b_ops = &xfs_dir3_leafn_buf_ops;
 226                         bp->b_ops->verify_read(bp);
 227                         return;
 228                 default:
 229                         xfs_verifier_error(bp, -EFSCORRUPTED, __this_address);
 230                         break;
 231         }
 232 }
 233
 234 /* Verify the structure of a da3 block. */
 235 static xfs_failaddr_t
 236 xfs_da3_node_verify_struct(
 237         struct xfs_buf          *bp)
 238 {
 239         struct xfs_da_blkinfo   *info = bp->b_addr;
 240
 241         switch (be16_to_cpu(info->magic)) {
 242         case XFS_DA3_NODE_MAGIC:
 243         case XFS_DA_NODE_MAGIC:
 244                 return xfs_da3_node_verify(bp);
 245         case XFS_ATTR_LEAF_MAGIC:
 246         case XFS_ATTR3_LEAF_MAGIC:
 247                 bp->b_ops = &xfs_attr3_leaf_buf_ops;
 248                 return bp->b_ops->verify_struct(bp);
 249         case XFS_DIR2_LEAFN_MAGIC:
 250         case XFS_DIR3_LEAFN_MAGIC:
 251                 bp->b_ops = &xfs_dir3_leafn_buf_ops;
 252                 return bp->b_ops->verify_struct(bp);
 253         default:
 254                 return __this_address;
 255         }
 256 }
 257
 258 const struct xfs_buf_ops xfs_da3_node_buf_ops = {
 259         .name = "xfs_da3_node",
 260         .verify_read = xfs_da3_node_read_verify,
 261         .verify_write = xfs_da3_node_write_verify,
 262         .verify_struct = xfs_da3_node_verify_struct,
 263 };
 264
 265 int
 266 xfs_da3_node_read(
 267         struct xfs_trans        *tp,
 268         struct xfs_inode        *dp,
 269         xfs_dablk_t             bno,
 270         xfs_daddr_t             mappedbno,
 271         struct xfs_buf          **bpp,
 272         int                     which_fork)
 273 {
 274         int                     err;
 275
 276         err = xfs_da_read_buf(tp, dp, bno, mappedbno, bpp,
 277                                         which_fork, &xfs_da3_node_buf_ops);
 278         if (!err && tp && *bpp) {
 279                 struct xfs_da_blkinfo   *info = (*bpp)->b_addr;
 280                 int                     type;
 281
 282                 switch (be16_to_cpu(info->magic)) {
 283                 case XFS_DA_NODE_MAGIC:
 284                 case XFS_DA3_NODE_MAGIC:
 285                         type = XFS_BLFT_DA_NODE_BUF;
 286                         break;
 287                 case XFS_ATTR_LEAF_MAGIC:
 288                 case XFS_ATTR3_LEAF_MAGIC:
 289                         type = XFS_BLFT_ATTR_LEAF_BUF;
 290                         break;
 291                 case XFS_DIR2_LEAFN_MAGIC:
 292                 case XFS_DIR3_LEAFN_MAGIC:
 293                         type = XFS_BLFT_DIR_LEAFN_BUF;
 294                         break;
 295                 default:
 296                         XFS_CORRUPTION_ERROR(__func__, XFS_ERRLEVEL_LOW,
 297                                         tp->t_mountp, info, sizeof(*info));
 298                         xfs_trans_brelse(tp, *bpp);
 299                         *bpp = NULL;
 300                         return -EFSCORRUPTED;
 301                 }
 302                 xfs_trans_buf_set_type(tp, *bpp, type);
 303         }
 304         return err;
 305 }
 306
 307 /*========================================================================
 308  * Routines used for growing the Btree.
 309  *========================================================================*/
 310
 311 /*
 312  * Create the initial contents of an intermediate node.
 313  */
 314 int
 315 xfs_da3_node_create(
 316         struct xfs_da_args      *args,
 317         xfs_dablk_t             blkno,
 318         int                     level,
 319         struct xfs_buf          **bpp,
 320         int                     whichfork)
 321 {
 322         struct xfs_da_intnode   *node;
 323         struct xfs_trans        *tp = args->trans;
 324         struct xfs_mount        *mp = tp->t_mountp;
 325         struct xfs_da3_icnode_hdr ichdr = {0};
 326         struct xfs_buf          *bp;
 327         int                     error;
 328         struct xfs_inode        *dp = args->dp;
 329
 330         trace_xfs_da_node_create(args);
 331         ASSERT(level <= XFS_DA_NODE_MAXDEPTH);
 332
 333         error = xfs_da_get_buf(tp, dp, blkno, -1, &bp, whichfork);
 334         if (error)
 335                 return error;
 336         bp->b_ops = &xfs_da3_node_buf_ops;
 337         xfs_trans_buf_set_type(tp, bp, XFS_BLFT_DA_NODE_BUF);
 338         node = bp->b_addr;
 339
 340         if (xfs_sb_version_hascrc(&mp->m_sb)) {
 341                 struct xfs_da3_node_hdr *hdr3 = bp->b_addr;
 342
 343                 memset(hdr3, 0, sizeof(struct xfs_da3_node_hdr));
 344                 ichdr.magic = XFS_DA3_NODE_MAGIC;
 345                 hdr3->info.blkno = cpu_to_be64(bp->b_bn);
 346                 hdr3->info.owner = cpu_to_be64(args->dp->i_ino);
 347                 uuid_copy(&hdr3->info.uuid, &mp->m_sb.sb_meta_uuid);
 348         } else {
 349                 ichdr.magic = XFS_DA_NODE_MAGIC;
 350         }
 351         ichdr.level = level;
 352
 353         dp->d_ops->node_hdr_to_disk(node, &ichdr);
 354         xfs_trans_log_buf(tp, bp,
 355                 XFS_DA_LOGRANGE(node, &node->hdr, dp->d_ops->node_hdr_size));
 356
 357         *bpp = bp;
 358         return 0;
 359 }
 360
 361 /*
 362  * Split a leaf node, rebalance, then possibly split
 363  * intermediate nodes, rebalance, etc.
 364  */
 365 int                                                     /* error */
 366 xfs_da3_split(
 367         struct xfs_da_state     *state)
 368 {
 369         struct xfs_da_state_blk *oldblk;
 370         struct xfs_da_state_blk *newblk;
 371         struct xfs_da_state_blk *addblk;
 372         struct xfs_da_intnode   *node;
 373         int                     max;
 374         int                     action = 0;
 375         int                     error;
 376         int                     i;
 377
 378         trace_xfs_da_split(state->args);
 379
 380         /*
 381          * Walk back up the tree splitting/inserting/adjusting as necessary.
 382          * If we need to insert and there isn't room, split the node, then
 383          * decide which fragment to insert the new block from below into.
 384          * Note that we may split the root this way, but we need more fixup.
 385          */
 386         max = state->path.active - 1;
 387         ASSERT((max >= 0) && (max < XFS_DA_NODE_MAXDEPTH));
 388         ASSERT(state->path.blk[max].magic == XFS_ATTR_LEAF_MAGIC ||
 389                state->path.blk[max].magic == XFS_DIR2_LEAFN_MAGIC);
 390
 391         addblk = &state->path.blk[max];         /* initial dummy value */
 392         for (i = max; (i >= 0) && addblk; state->path.active--, i--) {
 393                 oldblk = &state->path.blk[i];
 394                 newblk = &state->altpath.blk[i];
 395
 396                 /*
 397                  * If a leaf node then
 398                  *     Allocate a new leaf node, then rebalance across them.
 399                  * else if an intermediate node then
 400                  *     We split on the last layer, must we split the node?
 401                  */
 402                 switch (oldblk->magic) {
 403                 case XFS_ATTR_LEAF_MAGIC:
 404                         error = xfs_attr3_leaf_split(state, oldblk, newblk);
 405                         if ((error != 0) && (error != -ENOSPC)) {
 406                                 return error;   /* GROT: attr is inconsistent */
 407                         }
 408                         if (!error) {
 409                                 addblk = newblk;
 410                                 break;
 411                         }
 412                         /*
 413                          * Entry wouldn't fit, split the leaf again. The new
 414                          * extrablk will be consumed by xfs_da3_node_split if
 415                          * the node is split.
 416                          */
 417                         state->extravalid = 1;
 418                         if (state->inleaf) {
 419                                 state->extraafter = 0;  /* before newblk */
 420                                 trace_xfs_attr_leaf_split_before(state->args);
 421                                 error = xfs_attr3_leaf_split(state, oldblk,
 422                                                             &state->extrablk);
 423                         } else {
 424                                 state->extraafter = 1;  /* after newblk */
 425                                 trace_xfs_attr_leaf_split_after(state->args);
 426                                 error = xfs_attr3_leaf_split(state, newblk,
 427                                                             &state->extrablk);
 428                         }
 429                         if (error)
 430                                 return error;   /* GROT: attr inconsistent */
 431                         addblk = newblk;
 432                         break;
 433                 case XFS_DIR2_LEAFN_MAGIC:
 434                         error = xfs_dir2_leafn_split(state, oldblk, newblk);
 435                         if (error)
 436                                 return error;
 437                         addblk = newblk;
 438                         break;
 439                 case XFS_DA_NODE_MAGIC:
 440                         error = xfs_da3_node_split(state, oldblk, newblk, addblk,
 441                                                          max - i, &action);
 442                         addblk->bp = NULL;
 443                         if (error)
 444                                 return error;   /* GROT: dir is inconsistent */
 445                         /*
 446                          * Record the newly split block for the next time thru?
 447                          */
 448                         if (action)
 449                                 addblk = newblk;
 450                         else
 451                                 addblk = NULL;
 452                         break;
 453                 }
 454
 455                 /*
 456                  * Update the btree to show the new hashval for this child.
 457                  */
 458                 xfs_da3_fixhashpath(state, &state->path);
 459         }
 460         if (!addblk)
 461                 return 0;
 462
 463         /*
 464          * xfs_da3_node_split() should have consumed any extra blocks we added
 465          * during a double leaf split in the attr fork. This is guaranteed as
 466          * we can't be here if the attr fork only has a single leaf block.
 467          */
 468         ASSERT(state->extravalid == 0 ||
 469                state->path.blk[max].magic == XFS_DIR2_LEAFN_MAGIC);
 470
 471         /*
 472          * Split the root node.
 473          */
 474         ASSERT(state->path.active == 0);
 475         oldblk = &state->path.blk[0];
 476         error = xfs_da3_root_split(state, oldblk, addblk);
 477         if (error) {
 478                 addblk->bp = NULL;
 479                 return error;   /* GROT: dir is inconsistent */
 480         }
 481
 482         /*
 483          * Update pointers to the node which used to be block 0 and just got
 484          * bumped because of the addition of a new root node.  Note that the
 485          * original block 0 could be at any position in the list of blocks in
 486          * the tree.
 487          *
 488          * Note: the magic numbers and sibling pointers are in the same physical
 489          * place for both v2 and v3 headers (by design). Hence it doesn't matter
 490          * which version of the xfs_da_intnode structure we use here as the
 491          * result will be the same using either structure.
 492          */
 493         node = oldblk->bp->b_addr;
 494         if (node->hdr.info.forw) {
 495                 ASSERT(be32_to_cpu(node->hdr.info.forw) == addblk->blkno);
 496                 node = addblk->bp->b_addr;
 497                 node->hdr.info.back = cpu_to_be32(oldblk->blkno);
 498                 xfs_trans_log_buf(state->args->trans, addblk->bp,
 499                                   XFS_DA_LOGRANGE(node, &node->hdr.info,
 500                                   sizeof(node->hdr.info)));
 501         }
 502         node = oldblk->bp->b_addr;
 503         if (node->hdr.info.back) {
 504                 ASSERT(be32_to_cpu(node->hdr.info.back) == addblk->blkno);
 505                 node = addblk->bp->b_addr;
 506                 node->hdr.info.forw = cpu_to_be32(oldblk->blkno);
 507                 xfs_trans_log_buf(state->args->trans, addblk->bp,
 508                                   XFS_DA_LOGRANGE(node, &node->hdr.info,
 509                                   sizeof(node->hdr.info)));
 510         }
 511         addblk->bp = NULL;
 512         return 0;
 513 }
 514
 515 /*
 516  * Split the root.  We have to create a new root and point to the two
 517  * parts (the split old root) that we just created.  Copy block zero to
 518  * the EOF, extending the inode in process.
 519  */
 520 STATIC int                                              /* error */
 521 xfs_da3_root_split(
 522         struct xfs_da_state     *state,
 523         struct xfs_da_state_blk *blk1,
 524         struct xfs_da_state_blk *blk2)
 525 {
 526         struct xfs_da_intnode   *node;
 527         struct xfs_da_intnode   *oldroot;
 528         struct xfs_da_node_entry *btree;
 529         struct xfs_da3_icnode_hdr nodehdr;
 530         struct xfs_da_args      *args;
 531         struct xfs_buf          *bp;
 532         struct xfs_inode        *dp;
 533         struct xfs_trans        *tp;
 534         struct xfs_dir2_leaf    *leaf;
 535         xfs_dablk_t             blkno;
 536         int                     level;
 537         int                     error;
 538         int                     size;
 539
 540         trace_xfs_da_root_split(state->args);
 541
 542         /*
 543          * Copy the existing (incorrect) block from the root node position
 544          * to a free space somewhere.
 545          */
 546         args = state->args;
 547         error = xfs_da_grow_inode(args, &blkno);
 548         if (error)
 549                 return error;
 550
 551         dp = args->dp;
 552         tp = args->trans;
 553         error = xfs_da_get_buf(tp, dp, blkno, -1, &bp, args->whichfork);
 554         if (error)
 555                 return error;
 556         node = bp->b_addr;
 557         oldroot = blk1->bp->b_addr;
 558         if (oldroot->hdr.info.magic == cpu_to_be16(XFS_DA_NODE_MAGIC) ||
 559             oldroot->hdr.info.magic == cpu_to_be16(XFS_DA3_NODE_MAGIC)) {
 560                 struct xfs_da3_icnode_hdr icnodehdr;
 561
 562                 dp->d_ops->node_hdr_from_disk(&icnodehdr, oldroot);
 563                 btree = dp->d_ops->node_tree_p(oldroot);
 564                 size = (int)((char *)&btree[icnodehdr.count] - (char *)oldroot);
 565                 level = icnodehdr.level;
 566
 567                 /*
 568                  * we are about to copy oldroot to bp, so set up the type
 569                  * of bp while we know exactly what it will be.
 570                  */
 571                 xfs_trans_buf_set_type(tp, bp, XFS_BLFT_DA_NODE_BUF);
 572         } else {
 573                 struct xfs_dir3_icleaf_hdr leafhdr;
 574                 struct xfs_dir2_leaf_entry *ents;
 575
 576                 leaf = (xfs_dir2_leaf_t *)oldroot;
 577                 dp->d_ops->leaf_hdr_from_disk(&leafhdr, leaf);
 578                 ents = dp->d_ops->leaf_ents_p(leaf);
 579
 580                 ASSERT(leafhdr.magic == XFS_DIR2_LEAFN_MAGIC ||
 581                        leafhdr.magic == XFS_DIR3_LEAFN_MAGIC);
 582                 size = (int)((char *)&ents[leafhdr.count] - (char *)leaf);
 583                 level = 0;
 584
 585                 /*
 586                  * we are about to copy oldroot to bp, so set up the type
 587                  * of bp while we know exactly what it will be.
 588                  */
 589                 xfs_trans_buf_set_type(tp, bp, XFS_BLFT_DIR_LEAFN_BUF);
 590         }
 591
 592         /*
 593          * we can copy most of the information in the node from one block to
 594          * another, but for CRC enabled headers we have to make sure that the
 595          * block specific identifiers are kept intact. We update the buffer
 596          * directly for this.
 597          */
 598         memcpy(node, oldroot, size);
 599         if (oldroot->hdr.info.magic == cpu_to_be16(XFS_DA3_NODE_MAGIC) ||
 600             oldroot->hdr.info.magic == cpu_to_be16(XFS_DIR3_LEAFN_MAGIC)) {
 601                 struct xfs_da3_intnode *node3 = (struct xfs_da3_intnode *)node;
 602
 603                 node3->hdr.info.blkno = cpu_to_be64(bp->b_bn);
 604         }
 605         xfs_trans_log_buf(tp, bp, 0, size - 1);
 606
 607         bp->b_ops = blk1->bp->b_ops;
 608         xfs_trans_buf_copy_type(bp, blk1->bp);
 609         blk1->bp = bp;
 610         blk1->blkno = blkno;
 611
 612         /*
 613          * Set up the new root node.
 614          */
 615         error = xfs_da3_node_create(args,
 616                 (args->whichfork == XFS_DATA_FORK) ? args->geo->leafblk : 0,
 617                 level + 1, &bp, args->whichfork);
 618         if (error)
 619                 return error;
 620
 621         node = bp->b_addr;
 622         dp->d_ops->node_hdr_from_disk(&nodehdr, node);
 623         btree = dp->d_ops->node_tree_p(node);
 624         btree[0].hashval = cpu_to_be32(blk1->hashval);
 625         btree[0].before = cpu_to_be32(blk1->blkno);
 626         btree[1].hashval = cpu_to_be32(blk2->hashval);
 627         btree[1].before = cpu_to_be32(blk2->blkno);
 628         nodehdr.count = 2;
 629         dp->d_ops->node_hdr_to_disk(node, &nodehdr);
 630
 631 #ifdef DEBUG
 632         if (oldroot->hdr.info.magic == cpu_to_be16(XFS_DIR2_LEAFN_MAGIC) ||
 633             oldroot->hdr.info.magic == cpu_to_be16(XFS_DIR3_LEAFN_MAGIC)) {
 634                 ASSERT(blk1->blkno >= args->geo->leafblk &&
 635                        blk1->blkno < args->geo->freeblk);
 636                 ASSERT(blk2->blkno >= args->geo->leafblk &&
 637                        blk2->blkno < args->geo->freeblk);
 638         }
 639 #endif
 640
 641         /* Header is already logged by xfs_da_node_create */
 642         xfs_trans_log_buf(tp, bp,
 643                 XFS_DA_LOGRANGE(node, btree, sizeof(xfs_da_node_entry_t) * 2));
 644
 645         return 0;
 646 }
 647
 648 /*
 649  * Split the node, rebalance, then add the new entry.
 650  */
 651 STATIC int                                              /* error */
 652 xfs_da3_node_split(
 653         struct xfs_da_state     *state,
 654         struct xfs_da_state_blk *oldblk,
 655         struct xfs_da_state_blk *newblk,
 656         struct xfs_da_state_blk *addblk,
 657         int                     treelevel,
 658         int                     *result)
 659 {
 660         struct xfs_da_intnode   *node;
 661         struct xfs_da3_icnode_hdr nodehdr;
 662         xfs_dablk_t             blkno;
 663         int                     newcount;
 664         int                     error;
 665         int                     useextra;
 666         struct xfs_inode        *dp = state->args->dp;
 667
 668         trace_xfs_da_node_split(state->args);
 669
 670         node = oldblk->bp->b_addr;
 671         dp->d_ops->node_hdr_from_disk(&nodehdr, node);
 672
 673         /*
 674          * With V2 dirs the extra block is data or freespace.
 675          */
 676         useextra = state->extravalid && state->args->whichfork == XFS_ATTR_FORK;
 677         newcount = 1 + useextra;
 678         /*
 679          * Do we have to split the node?
 680          */
 681         if (nodehdr.count + newcount > state->args->geo->node_ents) {
 682                 /*
 683                  * Allocate a new node, add to the doubly linked chain of
 684                  * nodes, then move some of our excess entries into it.
 685                  */
 686                 error = xfs_da_grow_inode(state->args, &blkno);
 687                 if (error)
 688                         return error;   /* GROT: dir is inconsistent */
 689
 690                 error = xfs_da3_node_create(state->args, blkno, treelevel,
 691                                            &newblk->bp, state->args->whichfork);
 692                 if (error)
 693                         return error;   /* GROT: dir is inconsistent */
 694                 newblk->blkno = blkno;
 695                 newblk->magic = XFS_DA_NODE_MAGIC;
 696                 xfs_da3_node_rebalance(state, oldblk, newblk);
 697                 error = xfs_da3_blk_link(state, oldblk, newblk);
 698                 if (error)
 699                         return error;
 700                 *result = 1;
 701         } else {
 702                 *result = 0;
 703         }
 704
 705         /*
 706          * Insert the new entry(s) into the correct block
 707          * (updating last hashval in the process).
 708          *
 709          * xfs_da3_node_add() inserts BEFORE the given index,
 710          * and as a result of using node_lookup_int() we always
 711          * point to a valid entry (not after one), but a split
 712          * operation always results in a new block whose hashvals
 713          * FOLLOW the current block.
 714          *
 715          * If we had double-split op below us, then add the extra block too.
 716          */
 717         node = oldblk->bp->b_addr;
 718         dp->d_ops->node_hdr_from_disk(&nodehdr, node);
 719         if (oldblk->index <= nodehdr.count) {
 720                 oldblk->index++;
 721                 xfs_da3_node_add(state, oldblk, addblk);
 722                 if (useextra) {
 723                         if (state->extraafter)
 724                                 oldblk->index++;
 725                         xfs_da3_node_add(state, oldblk, &state->extrablk);
 726                         state->extravalid = 0;
 727                 }
 728         } else {
 729                 newblk->index++;
 730                 xfs_da3_node_add(state, newblk, addblk);
 731                 if (useextra) {
 732                         if (state->extraafter)
 733                                 newblk->index++;
 734                         xfs_da3_node_add(state, newblk, &state->extrablk);
 735                         state->extravalid = 0;
 736                 }
 737         }
 738
 739         return 0;
 740 }
 741
 742 /*
 743  * Balance the btree elements between two intermediate nodes,
 744  * usually one full and one empty.
 745  *
 746  * NOTE: if blk2 is empty, then it will get the upper half of blk1.
 747  */
 748 STATIC void
 749 xfs_da3_node_rebalance(
 750         struct xfs_da_state     *state,
 751         struct xfs_da_state_blk *blk1,
 752         struct xfs_da_state_blk *blk2)
 753 {
 754         struct xfs_da_intnode   *node1;
 755         struct xfs_da_intnode   *node2;
 756         struct xfs_da_intnode   *tmpnode;
 757         struct xfs_da_node_entry *btree1;
 758         struct xfs_da_node_entry *btree2;
 759         struct xfs_da_node_entry *btree_s;
 760         struct xfs_da_node_entry *btree_d;
 761         struct xfs_da3_icnode_hdr nodehdr1;
 762         struct xfs_da3_icnode_hdr nodehdr2;
 763         struct xfs_trans        *tp;
 764         int                     count;
 765         int                     tmp;
 766         int                     swap = 0;
 767         struct xfs_inode        *dp = state->args->dp;
 768
 769         trace_xfs_da_node_rebalance(state->args);
 770
 771         node1 = blk1->bp->b_addr;
 772         node2 = blk2->bp->b_addr;
 773         dp->d_ops->node_hdr_from_disk(&nodehdr1, node1);
 774         dp->d_ops->node_hdr_from_disk(&nodehdr2, node2);
 775         btree1 = dp->d_ops->node_tree_p(node1);
 776         btree2 = dp->d_ops->node_tree_p(node2);
 777
 778         /*
 779          * Figure out how many entries need to move, and in which direction.
 780          * Swap the nodes around if that makes it simpler.
 781          */
 782         if (nodehdr1.count > 0 && nodehdr2.count > 0 &&
 783             ((be32_to_cpu(btree2[0].hashval) < be32_to_cpu(btree1[0].hashval)) ||
 784              (be32_to_cpu(btree2[nodehdr2.count - 1].hashval) <
 785                         be32_to_cpu(btree1[nodehdr1.count - 1].hashval)))) {
 786                 tmpnode = node1;
 787                 node1 = node2;
 788                 node2 = tmpnode;
 789                 dp->d_ops->node_hdr_from_disk(&nodehdr1, node1);
 790                 dp->d_ops->node_hdr_from_disk(&nodehdr2, node2);
 791                 btree1 = dp->d_ops->node_tree_p(node1);
 792                 btree2 = dp->d_ops->node_tree_p(node2);
 793                 swap = 1;
 794         }
 795
 796         count = (nodehdr1.count - nodehdr2.count) / 2;
 797         if (count == 0)
 798                 return;
 799         tp = state->args->trans;
 800         /*
 801          * Two cases: high-to-low and low-to-high.
 802          */
 803         if (count > 0) {
 804                 /*
 805                  * Move elements in node2 up to make a hole.
 806                  */
 807                 tmp = nodehdr2.count;
 808                 if (tmp > 0) {
 809                         tmp *= (uint)sizeof(xfs_da_node_entry_t);
 810                         btree_s = &btree2[0];
 811                         btree_d = &btree2[count];
 812                         memmove(btree_d, btree_s, tmp);
 813                 }
 814
 815                 /*
 816                  * Move the req'd B-tree elements from high in node1 to
 817                  * low in node2.
 818                  */
 819                 nodehdr2.count += count;
 820                 tmp = count * (uint)sizeof(xfs_da_node_entry_t);
 821                 btree_s = &btree1[nodehdr1.count - count];
 822                 btree_d = &btree2[0];
 823                 memcpy(btree_d, btree_s, tmp);
 824                 nodehdr1.count -= count;
 825         } else {
 826                 /*
 827                  * Move the req'd B-tree elements from low in node2 to
 828                  * high in node1.
 829                  */
 830                 count = -count;
 831                 tmp = count * (uint)sizeof(xfs_da_node_entry_t);
 832                 btree_s = &btree2[0];
 833                 btree_d = &btree1[nodehdr1.count];
 834                 memcpy(btree_d, btree_s, tmp);
 835                 nodehdr1.count += count;
 836
 837                 xfs_trans_log_buf(tp, blk1->bp,
 838                         XFS_DA_LOGRANGE(node1, btree_d, tmp));
 839
 840                 /*
 841                  * Move elements in node2 down to fill the hole.
 842                  */
 843                 tmp  = nodehdr2.count - count;
 844                 tmp *= (uint)sizeof(xfs_da_node_entry_t);
 845                 btree_s = &btree2[count];
 846                 btree_d = &btree2[0];
 847                 memmove(btree_d, btree_s, tmp);
 848                 nodehdr2.count -= count;
 849         }
 850
 851         /*
 852          * Log header of node 1 and all current bits of node 2.
 853          */
 854         dp->d_ops->node_hdr_to_disk(node1, &nodehdr1);
 855         xfs_trans_log_buf(tp, blk1->bp,
 856                 XFS_DA_LOGRANGE(node1, &node1->hdr, dp->d_ops->node_hdr_size));
 857
 858         dp->d_ops->node_hdr_to_disk(node2, &nodehdr2);
 859         xfs_trans_log_buf(tp, blk2->bp,
 860                 XFS_DA_LOGRANGE(node2, &node2->hdr,
 861                                 dp->d_ops->node_hdr_size +
 862                                 (sizeof(btree2[0]) * nodehdr2.count)));
 863
 864         /*
 865          * Record the last hashval from each block for upward propagation.
 866          * (note: don't use the swapped node pointers)
 867          */
 868         if (swap) {
 869                 node1 = blk1->bp->b_addr;
 870                 node2 = blk2->bp->b_addr;
 871                 dp->d_ops->node_hdr_from_disk(&nodehdr1, node1);
 872                 dp->d_ops->node_hdr_from_disk(&nodehdr2, node2);
 873                 btree1 = dp->d_ops->node_tree_p(node1);
 874                 btree2 = dp->d_ops->node_tree_p(node2);
 875         }
 876         blk1->hashval = be32_to_cpu(btree1[nodehdr1.count - 1].hashval);
 877         blk2->hashval = be32_to_cpu(btree2[nodehdr2.count - 1].hashval);
 878
 879         /*
 880          * Adjust the expected index for insertion.
 881          */
 882         if (blk1->index >= nodehdr1.count) {
 883                 blk2->index = blk1->index - nodehdr1.count;
 884                 blk1->index = nodehdr1.count + 1;       /* make it invalid */
 885         }
 886 }
 887
 888 /*
 889  * Add a new entry to an intermediate node.
 890  */
 891 STATIC void
 892 xfs_da3_node_add(
 893         struct xfs_da_state     *state,
 894         struct xfs_da_state_blk *oldblk,
 895         struct xfs_da_state_blk *newblk)
 896 {
 897         struct xfs_da_intnode   *node;
 898         struct xfs_da3_icnode_hdr nodehdr;
 899         struct xfs_da_node_entry *btree;
 900         int                     tmp;
 901         struct xfs_inode        *dp = state->args->dp;
 902
 903         trace_xfs_da_node_add(state->args);
 904
 905         node = oldblk->bp->b_addr;
 906         dp->d_ops->node_hdr_from_disk(&nodehdr, node);
 907         btree = dp->d_ops->node_tree_p(node);
 908
 909         ASSERT(oldblk->index >= 0 && oldblk->index <= nodehdr.count);
 910         ASSERT(newblk->blkno != 0);
 911         if (state->args->whichfork == XFS_DATA_FORK)
 912                 ASSERT(newblk->blkno >= state->args->geo->leafblk &&
 913                        newblk->blkno < state->args->geo->freeblk);
 914
 915         /*
 916          * We may need to make some room before we insert the new node.
 917          */
 918         tmp = 0;
 919         if (oldblk->index < nodehdr.count) {
 920                 tmp = (nodehdr.count - oldblk->index) * (uint)sizeof(*btree);
 921                 memmove(&btree[oldblk->index + 1], &btree[oldblk->index], tmp);
 922         }
 923         btree[oldblk->index].hashval = cpu_to_be32(newblk->hashval);
 924         btree[oldblk->index].before = cpu_to_be32(newblk->blkno);
 925         xfs_trans_log_buf(state->args->trans, oldblk->bp,
 926                 XFS_DA_LOGRANGE(node, &btree[oldblk->index],
 927                                 tmp + sizeof(*btree)));
 928
 929         nodehdr.count += 1;
 930         dp->d_ops->node_hdr_to_disk(node, &nodehdr);
 931         xfs_trans_log_buf(state->args->trans, oldblk->bp,
 932                 XFS_DA_LOGRANGE(node, &node->hdr, dp->d_ops->node_hdr_size));
 933
 934         /*
 935          * Copy the last hash value from the oldblk to propagate upwards.
 936          */
 937         oldblk->hashval = be32_to_cpu(btree[nodehdr.count - 1].hashval);
 938 }
 939
 940 /*========================================================================
 941  * Routines used for shrinking the Btree.
 942  *========================================================================*/
 943
 944 /*
 945  * Deallocate an empty leaf node, remove it from its parent,
 946  * possibly deallocating that block, etc...
 947  */
 948 int
 949 xfs_da3_join(
 950         struct xfs_da_state     *state)
 951 {
 952         struct xfs_da_state_blk *drop_blk;
 953         struct xfs_da_state_blk *save_blk;
 954         int                     action = 0;
 955         int                     error;
 956
 957         trace_xfs_da_join(state->args);
 958
 959         drop_blk = &state->path.blk[ state->path.active-1 ];
 960         save_blk = &state->altpath.blk[ state->path.active-1 ];
 961         ASSERT(state->path.blk[0].magic == XFS_DA_NODE_MAGIC);
 962         ASSERT(drop_blk->magic == XFS_ATTR_LEAF_MAGIC ||
 963                drop_blk->magic == XFS_DIR2_LEAFN_MAGIC);
 964
 965         /*
 966          * Walk back up the tree joining/deallocating as necessary.
 967          * When we stop dropping blocks, break out.
 968          */
 969         for (  ; state->path.active >= 2; drop_blk--, save_blk--,
 970                  state->path.active--) {
 971                 /*
 972                  * See if we can combine the block with a neighbor.
 973                  *   (action == 0) => no options, just leave
 974                  *   (action == 1) => coalesce, then unlink
 975                  *   (action == 2) => block empty, unlink it
 976                  */
 977                 switch (drop_blk->magic) {
 978                 case XFS_ATTR_LEAF_MAGIC:
 979                         error = xfs_attr3_leaf_toosmall(state, &action);
 980                         if (error)
 981                                 return error;
 982                         if (action == 0)
 983                                 return 0;
 984                         xfs_attr3_leaf_unbalance(state, drop_blk, save_blk);
 985                         break;
 986                 case XFS_DIR2_LEAFN_MAGIC:
 987                         error = xfs_dir2_leafn_toosmall(state, &action);
 988                         if (error)
 989                                 return error;
 990                         if (action == 0)
 991                                 return 0;
 992                         xfs_dir2_leafn_unbalance(state, drop_blk, save_blk);
 993                         break;
 994                 case XFS_DA_NODE_MAGIC:
 995                         /*
 996                          * Remove the offending node, fixup hashvals,
 997                          * check for a toosmall neighbor.
 998                          */
 999                         xfs_da3_node_remove(state, drop_blk);
1000                         xfs_da3_fixhashpath(state, &state->path);
1001                         error = xfs_da3_node_toosmall(state, &action);
1002                         if (error)
1003                                 return error;
1004                         if (action == 0)
1005                                 return 0;
1006                         xfs_da3_node_unbalance(state, drop_blk, save_blk);
1007                         break;
1008                 }
1009                 xfs_da3_fixhashpath(state, &state->altpath);
1010                 error = xfs_da3_blk_unlink(state, drop_blk, save_blk);
1011                 xfs_da_state_kill_altpath(state);
1012                 if (error)
1013                         return error;
1014                 error = xfs_da_shrink_inode(state->args, drop_blk->blkno,
1015                                                          drop_blk->bp);
1016                 drop_blk->bp = NULL;
1017                 if (error)
1018                         return error;
1019         }
1020         /*
1021          * We joined all the way to the top.  If it turns out that
1022          * we only have one entry in the root, make the child block
1023          * the new root.
1024          */
1025         xfs_da3_node_remove(state, drop_blk);
1026         xfs_da3_fixhashpath(state, &state->path);
1027         error = xfs_da3_root_join(state, &state->path.blk[0]);
1028         return error;
1029 }
1030
1031 #ifdef  DEBUG
1032 static void
1033 xfs_da_blkinfo_onlychild_validate(struct xfs_da_blkinfo *blkinfo, __u16 level)
1034 {
1035         __be16  magic = blkinfo->magic;
1036
1037         if (level == 1) {
1038                 ASSERT(magic == cpu_to_be16(XFS_DIR2_LEAFN_MAGIC) ||
1039                        magic == cpu_to_be16(XFS_DIR3_LEAFN_MAGIC) ||
1040                        magic == cpu_to_be16(XFS_ATTR_LEAF_MAGIC) ||
1041                        magic == cpu_to_be16(XFS_ATTR3_LEAF_MAGIC));
1042         } else {
1043                 ASSERT(magic == cpu_to_be16(XFS_DA_NODE_MAGIC) ||
1044                        magic == cpu_to_be16(XFS_DA3_NODE_MAGIC));
1045         }
1046         ASSERT(!blkinfo->forw);
1047         ASSERT(!blkinfo->back);
1048 }
1049 #else   /* !DEBUG */
1050 #define xfs_da_blkinfo_onlychild_validate(blkinfo, level)
1051 #endif  /* !DEBUG */
1052
1053 /*
1054  * We have only one entry in the root.  Copy the only remaining child of
1055  * the old root to block 0 as the new root node.
1056  */
1057 STATIC int
1058 xfs_da3_root_join(
1059         struct xfs_da_state     *state,
1060         struct xfs_da_state_blk *root_blk)
1061 {
1062         struct xfs_da_intnode   *oldroot;
1063         struct xfs_da_args      *args;
1064         xfs_dablk_t             child;
1065         struct xfs_buf          *bp;
1066         struct xfs_da3_icnode_hdr oldroothdr;
1067         struct xfs_da_node_entry *btree;
1068         int                     error;
1069         struct xfs_inode        *dp = state->args->dp;
1070
1071         trace_xfs_da_root_join(state->args);
1072
1073         ASSERT(root_blk->magic == XFS_DA_NODE_MAGIC);
1074
1075         args = state->args;
1076         oldroot = root_blk->bp->b_addr;
1077         dp->d_ops->node_hdr_from_disk(&oldroothdr, oldroot);
1078         ASSERT(oldroothdr.forw == 0);
1079         ASSERT(oldroothdr.back == 0);
1080
1081         /*
1082          * If the root has more than one child, then don't do anything.
1083          */
1084         if (oldroothdr.count > 1)
1085                 return 0;
1086
1087         /*
1088          * Read in the (only) child block, then copy those bytes into
1089          * the root block's buffer and free the original child block.
1090          */
1091         btree = dp->d_ops->node_tree_p(oldroot);
1092         child = be32_to_cpu(btree[0].before);
1093         ASSERT(child != 0);
1094         error = xfs_da3_node_read(args->trans, dp, child, -1, &bp,
1095                                              args->whichfork);
1096         if (error)
1097                 return error;
1098         xfs_da_blkinfo_onlychild_validate(bp->b_addr, oldroothdr.level);
1099
1100         /*
1101          * This could be copying a leaf back into the root block in the case of
1102          * there only being a single leaf block left in the tree. Hence we have
1103          * to update the b_ops pointer as well to match the buffer type change
1104          * that could occur. For dir3 blocks we also need to update the block
1105          * number in the buffer header.
1106          */
1107         memcpy(root_blk->bp->b_addr, bp->b_addr, args->geo->blksize);
1108         root_blk->bp->b_ops = bp->b_ops;
1109         xfs_trans_buf_copy_type(root_blk->bp, bp);
1110         if (oldroothdr.magic == XFS_DA3_NODE_MAGIC) {
1111                 struct xfs_da3_blkinfo *da3 = root_blk->bp->b_addr;
1112                 da3->blkno = cpu_to_be64(root_blk->bp->b_bn);
1113         }
1114         xfs_trans_log_buf(args->trans, root_blk->bp, 0,
1115                           args->geo->blksize - 1);
1116         error = xfs_da_shrink_inode(args, child, bp);
1117         return error;
1118 }
1119
1120 /*
1121  * Check a node block and its neighbors to see if the block should be
1122  * collapsed into one or the other neighbor.  Always keep the block
1123  * with the smaller block number.
1124  * If the current block is over 50% full, don't try to join it, return 0.
1125  * If the block is empty, fill in the state structure and return 2.
1126  * If it can be collapsed, fill in the state structure and return 1.
1127  * If nothing can be done, return 0.
1128  */
1129 STATIC int
1130 xfs_da3_node_toosmall(
1131         struct xfs_da_state     *state,
1132         int                     *action)
1133 {
1134         struct xfs_da_intnode   *node;
1135         struct xfs_da_state_blk *blk;
1136         struct xfs_da_blkinfo   *info;
1137         xfs_dablk_t             blkno;
1138         struct xfs_buf          *bp;
1139         struct xfs_da3_icnode_hdr nodehdr;
1140         int                     count;
1141         int                     forward;
1142         int                     error;
1143         int                     retval;
1144         int                     i;
1145         struct xfs_inode        *dp = state->args->dp;
1146
1147         trace_xfs_da_node_toosmall(state->args);
1148
1149         /*
1150          * Check for the degenerate case of the block being over 50% full.
1151          * If so, it's not worth even looking to see if we might be able
1152          * to coalesce with a sibling.
1153          */
1154         blk = &state->path.blk[ state->path.active-1 ];
1155         info = blk->bp->b_addr;
1156         node = (xfs_da_intnode_t *)info;
1157         dp->d_ops->node_hdr_from_disk(&nodehdr, node);
1158         if (nodehdr.count > (state->args->geo->node_ents >> 1)) {
1159                 *action = 0;    /* blk over 50%, don't try to join */
1160                 return 0;       /* blk over 50%, don't try to join */
1161         }
1162
1163         /*
1164          * Check for the degenerate case of the block being empty.
1165          * If the block is empty, we'll simply delete it, no need to
1166          * coalesce it with a sibling block.  We choose (arbitrarily)
1167          * to merge with the forward block unless it is NULL.
1168          */
1169         if (nodehdr.count == 0) {
1170                 /*
1171                  * Make altpath point to the block we want to keep and
1172                  * path point to the block we want to drop (this one).
1173                  */
1174                 forward = (info->forw != 0);
1175                 memcpy(&state->altpath, &state->path, sizeof(state->path));
1176                 error = xfs_da3_path_shift(state, &state->altpath, forward,
1177                                                  0, &retval);
1178                 if (error)
1179                         return error;
1180                 if (retval) {
1181                         *action = 0;
1182                 } else {
1183                         *action = 2;
1184                 }
1185                 return 0;
1186         }
1187
1188         /*
1189          * Examine each sibling block to see if we can coalesce with
1190          * at least 25% free space to spare.  We need to figure out
1191          * whether to merge with the forward or the backward block.
1192          * We prefer coalescing with the lower numbered sibling so as
1193          * to shrink a directory over time.
1194          */
1195         count  = state->args->geo->node_ents;
1196         count -= state->args->geo->node_ents >> 2;
1197         count -= nodehdr.count;
1198
1199         /* start with smaller blk num */
1200         forward = nodehdr.forw < nodehdr.back;
1201         for (i = 0; i < 2; forward = !forward, i++) {
1202                 struct xfs_da3_icnode_hdr thdr;
1203                 if (forward)
1204                         blkno = nodehdr.forw;
1205                 else
1206                         blkno = nodehdr.back;
1207                 if (blkno == 0)
1208                         continue;
1209                 error = xfs_da3_node_read(state->args->trans, dp,
1210                                         blkno, -1, &bp, state->args->whichfork);
1211                 if (error)
1212                         return error;
1213
1214                 node = bp->b_addr;
1215                 dp->d_ops->node_hdr_from_disk(&thdr, node);
1216                 xfs_trans_brelse(state->args->trans, bp);
1217
1218                 if (count - thdr.count >= 0)
1219                         break;  /* fits with at least 25% to spare */
1220         }
1221         if (i >= 2) {
1222                 *action = 0;
1223                 return 0;
1224         }
1225
1226         /*
1227          * Make altpath point to the block we want to keep (the lower
1228          * numbered block) and path point to the block we want to drop.
1229          */
1230         memcpy(&state->altpath, &state->path, sizeof(state->path));
1231         if (blkno < blk->blkno) {
1232                 error = xfs_da3_path_shift(state, &state->altpath, forward,
1233                                                  0, &retval);
1234         } else {
1235                 error = xfs_da3_path_shift(state, &state->path, forward,
1236                                                  0, &retval);
1237         }
1238         if (error)
1239                 return error;
1240         if (retval) {
1241                 *action = 0;
1242                 return 0;
1243         }
1244         *action = 1;
1245         return 0;
1246 }
1247
1248 /*
1249  * Pick up the last hashvalue from an intermediate node.
1250  */
1251 STATIC uint
1252 xfs_da3_node_lasthash(
1253         struct xfs_inode        *dp,
1254         struct xfs_buf          *bp,
1255         int                     *count)
1256 {
1257         struct xfs_da_intnode    *node;
1258         struct xfs_da_node_entry *btree;
1259         struct xfs_da3_icnode_hdr nodehdr;
1260
1261         node = bp->b_addr;
1262         dp->d_ops->node_hdr_from_disk(&nodehdr, node);
1263         if (count)
1264                 *count = nodehdr.count;
1265         if (!nodehdr.count)
1266                 return 0;
1267         btree = dp->d_ops->node_tree_p(node);
1268         return be32_to_cpu(btree[nodehdr.count - 1].hashval);
1269 }
1270
1271 /*
1272  * Walk back up the tree adjusting hash values as necessary,
1273  * when we stop making changes, return.
1274  */
1275 void
1276 xfs_da3_fixhashpath(
1277         struct xfs_da_state     *state,
1278         struct xfs_da_state_path *path)
1279 {
1280         struct xfs_da_state_blk *blk;
1281         struct xfs_da_intnode   *node;
1282         struct xfs_da_node_entry *btree;
1283         xfs_dahash_t            lasthash=0;
1284         int                     level;
1285         int                     count;
1286         struct xfs_inode        *dp = state->args->dp;
1287
1288         trace_xfs_da_fixhashpath(state->args);
1289
1290         level = path->active-1;
1291         blk = &path->blk[ level ];
1292         switch (blk->magic) {
1293         case XFS_ATTR_LEAF_MAGIC:
1294                 lasthash = xfs_attr_leaf_lasthash(blk->bp, &count);
1295                 if (count == 0)
1296                         return;
1297                 break;
1298         case XFS_DIR2_LEAFN_MAGIC:
1299                 lasthash = xfs_dir2_leaf_lasthash(dp, blk->bp, &count);
1300                 if (count == 0)
1301                         return;
1302                 break;
1303         case XFS_DA_NODE_MAGIC:
1304                 lasthash = xfs_da3_node_lasthash(dp, blk->bp, &count);
1305                 if (count == 0)
1306                         return;
1307                 break;
1308         }
1309         for (blk--, level--; level >= 0; blk--, level--) {
1310                 struct xfs_da3_icnode_hdr nodehdr;
1311
1312                 node = blk->bp->b_addr;
1313                 dp->d_ops->node_hdr_from_disk(&nodehdr, node);
1314                 btree = dp->d_ops->node_tree_p(node);
1315                 if (be32_to_cpu(btree[blk->index].hashval) == lasthash)
1316                         break;
1317                 blk->hashval = lasthash;
1318                 btree[blk->index].hashval = cpu_to_be32(lasthash);
1319                 xfs_trans_log_buf(state->args->trans, blk->bp,
1320                                   XFS_DA_LOGRANGE(node, &btree[blk->index],
1321                                                   sizeof(*btree)));
1322
1323                 lasthash = be32_to_cpu(btree[nodehdr.count - 1].hashval);
1324         }
1325 }
1326
1327 /*
1328  * Remove an entry from an intermediate node.
1329  */
1330 STATIC void
1331 xfs_da3_node_remove(
1332         struct xfs_da_state     *state,
1333         struct xfs_da_state_blk *drop_blk)
1334 {
1335         struct xfs_da_intnode   *node;
1336         struct xfs_da3_icnode_hdr nodehdr;
1337         struct xfs_da_node_entry *btree;
1338         int                     index;
1339         int                     tmp;
1340         struct xfs_inode        *dp = state->args->dp;
1341
1342         trace_xfs_da_node_remove(state->args);
1343
1344         node = drop_blk->bp->b_addr;
1345         dp->d_ops->node_hdr_from_disk(&nodehdr, node);
1346         ASSERT(drop_blk->index < nodehdr.count);
1347         ASSERT(drop_blk->index >= 0);
1348
1349         /*
1350          * Copy over the offending entry, or just zero it out.
1351          */
1352         index = drop_blk->index;
1353         btree = dp->d_ops->node_tree_p(node);
1354         if (index < nodehdr.count - 1) {
1355                 tmp  = nodehdr.count - index - 1;
1356                 tmp *= (uint)sizeof(xfs_da_node_entry_t);
1357                 memmove(&btree[index], &btree[index + 1], tmp);
1358                 xfs_trans_log_buf(state->args->trans, drop_blk->bp,
1359                     XFS_DA_LOGRANGE(node, &btree[index], tmp));
1360                 index = nodehdr.count - 1;
1361         }
1362         memset(&btree[index], 0, sizeof(xfs_da_node_entry_t));
1363         xfs_trans_log_buf(state->args->trans, drop_blk->bp,
1364             XFS_DA_LOGRANGE(node, &btree[index], sizeof(btree[index])));
1365         nodehdr.count -= 1;
1366         dp->d_ops->node_hdr_to_disk(node, &nodehdr);
1367         xfs_trans_log_buf(state->args->trans, drop_blk->bp,
1368             XFS_DA_LOGRANGE(node, &node->hdr, dp->d_ops->node_hdr_size));
1369
1370         /*
1371          * Copy the last hash value from the block to propagate upwards.
1372          */
1373         drop_blk->hashval = be32_to_cpu(btree[index - 1].hashval);
1374 }
1375
1376 /*
1377  * Unbalance the elements between two intermediate nodes,
1378  * move all Btree elements from one node into another.
1379  */
1380 STATIC void
1381 xfs_da3_node_unbalance(
1382         struct xfs_da_state     *state,
1383         struct xfs_da_state_blk *drop_blk,
1384         struct xfs_da_state_blk *save_blk)
1385 {
1386         struct xfs_da_intnode   *drop_node;
1387         struct xfs_da_intnode   *save_node;
1388         struct xfs_da_node_entry *drop_btree;
1389         struct xfs_da_node_entry *save_btree;
1390         struct xfs_da3_icnode_hdr drop_hdr;
1391         struct xfs_da3_icnode_hdr save_hdr;
1392         struct xfs_trans        *tp;
1393         int                     sindex;
1394         int                     tmp;
1395         struct xfs_inode        *dp = state->args->dp;
1396
1397         trace_xfs_da_node_unbalance(state->args);
1398
1399         drop_node = drop_blk->bp->b_addr;
1400         save_node = save_blk->bp->b_addr;
1401         dp->d_ops->node_hdr_from_disk(&drop_hdr, drop_node);
1402         dp->d_ops->node_hdr_from_disk(&save_hdr, save_node);
1403         drop_btree = dp->d_ops->node_tree_p(drop_node);
1404         save_btree = dp->d_ops->node_tree_p(save_node);
1405         tp = state->args->trans;
1406
1407         /*
1408          * If the dying block has lower hashvals, then move all the
1409          * elements in the remaining block up to make a hole.
1410          */
1411         if ((be32_to_cpu(drop_btree[0].hashval) <
1412                         be32_to_cpu(save_btree[0].hashval)) ||
1413             (be32_to_cpu(drop_btree[drop_hdr.count - 1].hashval) <
1414                         be32_to_cpu(save_btree[save_hdr.count - 1].hashval))) {
1415                 /* XXX: check this - is memmove dst correct? */
1416                 tmp = save_hdr.count * sizeof(xfs_da_node_entry_t);
1417                 memmove(&save_btree[drop_hdr.count], &save_btree[0], tmp);
1418
1419                 sindex = 0;
1420                 xfs_trans_log_buf(tp, save_blk->bp,
1421                         XFS_DA_LOGRANGE(save_node, &save_btree[0],
1422                                 (save_hdr.count + drop_hdr.count) *
1423                                                 sizeof(xfs_da_node_entry_t)));
1424         } else {
1425                 sindex = save_hdr.count;
1426                 xfs_trans_log_buf(tp, save_blk->bp,
1427                         XFS_DA_LOGRANGE(save_node, &save_btree[sindex],
1428                                 drop_hdr.count * sizeof(xfs_da_node_entry_t)));
1429         }
1430
1431         /*
1432          * Move all the B-tree elements from drop_blk to save_blk.
1433          */
1434         tmp = drop_hdr.count * (uint)sizeof(xfs_da_node_entry_t);
1435         memcpy(&save_btree[sindex], &drop_btree[0], tmp);
1436         save_hdr.count += drop_hdr.count;
1437
1438         dp->d_ops->node_hdr_to_disk(save_node, &save_hdr);
1439         xfs_trans_log_buf(tp, save_blk->bp,
1440                 XFS_DA_LOGRANGE(save_node, &save_node->hdr,
1441                                 dp->d_ops->node_hdr_size));
1442
1443         /*
1444          * Save the last hashval in the remaining block for upward propagation.
1445          */
1446         save_blk->hashval = be32_to_cpu(save_btree[save_hdr.count - 1].hashval);
1447 }
1448
1449 /*========================================================================
1450  * Routines used for finding things in the Btree.
1451  *========================================================================*/
1452
1453 /*
1454  * Walk down the Btree looking for a particular filename, filling
1455  * in the state structure as we go.
1456  *
1457  * We will set the state structure to point to each of the elements
1458  * in each of the nodes where either the hashval is or should be.
1459  *
1460  * We support duplicate hashval's so for each entry in the current
1461  * node that could contain the desired hashval, descend.  This is a
1462  * pruned depth-first tree search.
1463  */
1464 int                                                     /* error */
1465 xfs_da3_node_lookup_int(
1466         struct xfs_da_state     *state,
1467         int                     *result)
1468 {
1469         struct xfs_da_state_blk *blk;
1470         struct xfs_da_blkinfo   *curr;
1471         struct xfs_da_intnode   *node;
1472         struct xfs_da_node_entry *btree;
1473         struct xfs_da3_icnode_hdr nodehdr;
1474         struct xfs_da_args      *args;
1475         xfs_dablk_t             blkno;
1476         xfs_dahash_t            hashval;
1477         xfs_dahash_t            btreehashval;
1478         int                     probe;
1479         int                     span;
1480         int                     max;
1481         int                     error;
1482         int                     retval;
1483         unsigned int            expected_level = 0;
1484         uint16_t                magic;
1485         struct xfs_inode        *dp = state->args->dp;
1486
1487         args = state->args;
1488
1489         /*
1490          * Descend thru the B-tree searching each level for the right
1491          * node to use, until the right hashval is found.
1492          */
1493         blkno = args->geo->leafblk;
1494         for (blk = &state->path.blk[0], state->path.active = 1;
1495                          state->path.active <= XFS_DA_NODE_MAXDEPTH;
1496                          blk++, state->path.active++) {
1497                 /*
1498                  * Read the next node down in the tree.
1499                  */
1500                 blk->blkno = blkno;
1501                 error = xfs_da3_node_read(args->trans, args->dp, blkno,
1502                                         -1, &blk->bp, args->whichfork);
1503                 if (error) {
1504                         blk->blkno = 0;
1505                         state->path.active--;
1506                         return error;
1507                 }
1508                 curr = blk->bp->b_addr;
1509                 magic = be16_to_cpu(curr->magic);
1510
1511                 if (magic == XFS_ATTR_LEAF_MAGIC ||
1512                     magic == XFS_ATTR3_LEAF_MAGIC) {
1513                         blk->magic = XFS_ATTR_LEAF_MAGIC;
1514                         blk->hashval = xfs_attr_leaf_lasthash(blk->bp, NULL);
1515                         break;
1516                 }
1517
1518                 if (magic == XFS_DIR2_LEAFN_MAGIC ||
1519                     magic == XFS_DIR3_LEAFN_MAGIC) {
1520                         blk->magic = XFS_DIR2_LEAFN_MAGIC;
1521                         blk->hashval = xfs_dir2_leaf_lasthash(args->dp,
1522                                                               blk->bp, NULL);
1523                         break;
1524                 }
1525
1526                 if (magic != XFS_DA_NODE_MAGIC && magic != XFS_DA3_NODE_MAGIC)
1527                         return -EFSCORRUPTED;
1528
1529                 blk->magic = XFS_DA_NODE_MAGIC;
1530
1531                 /*
1532                  * Search an intermediate node for a match.
1533                  */
1534                 node = blk->bp->b_addr;
1535                 dp->d_ops->node_hdr_from_disk(&nodehdr, node);
1536                 btree = dp->d_ops->node_tree_p(node);
1537
1538                 /* Tree taller than we can handle; bail out! */
1539                 if (nodehdr.level >= XFS_DA_NODE_MAXDEPTH)
1540                         return -EFSCORRUPTED;
1541
1542                 /* Check the level from the root. */
1543                 if (blkno == args->geo->leafblk)
1544                         expected_level = nodehdr.level - 1;
1545                 else if (expected_level != nodehdr.level)
1546                         return -EFSCORRUPTED;
1547                 else
1548                         expected_level--;
1549
1550                 max = nodehdr.count;
1551                 blk->hashval = be32_to_cpu(btree[max - 1].hashval);
1552
1553                 /*
1554                  * Binary search.  (note: small blocks will skip loop)
1555                  */
1556                 probe = span = max / 2;
1557                 hashval = args->hashval;
1558                 while (span > 4) {
1559                         span /= 2;
1560                         btreehashval = be32_to_cpu(btree[probe].hashval);
1561                         if (btreehashval < hashval)
1562                                 probe += span;
1563                         else if (btreehashval > hashval)
1564                                 probe -= span;
1565                         else
1566                                 break;
1567                 }
1568                 ASSERT((probe >= 0) && (probe < max));
1569                 ASSERT((span <= 4) ||
1570                         (be32_to_cpu(btree[probe].hashval) == hashval));
1571
1572                 /*
1573                  * Since we may have duplicate hashval's, find the first
1574                  * matching hashval in the node.
1575                  */
1576                 while (probe > 0 &&
1577                        be32_to_cpu(btree[probe].hashval) >= hashval) {
1578                         probe--;
1579                 }
1580                 while (probe < max &&
1581                        be32_to_cpu(btree[probe].hashval) < hashval) {
1582                         probe++;
1583                 }
1584
1585                 /*
1586                  * Pick the right block to descend on.
1587                  */
1588                 if (probe == max) {
1589                         blk->index = max - 1;
1590                         blkno = be32_to_cpu(btree[max - 1].before);
1591                 } else {
1592                         blk->index = probe;
1593                         blkno = be32_to_cpu(btree[probe].before);
1594                 }
1595
1596                 /* We can't point back to the root. */
1597                 if (blkno == args->geo->leafblk)
1598                         return -EFSCORRUPTED;
1599         }
1600
1601         if (expected_level != 0)
1602                 return -EFSCORRUPTED;
1603
1604         /*
1605          * A leaf block that ends in the hashval that we are interested in
1606          * (final hashval == search hashval) means that the next block may
1607          * contain more entries with the same hashval, shift upward to the
1608          * next leaf and keep searching.
1609          */
1610         for (;;) {
1611                 if (blk->magic == XFS_DIR2_LEAFN_MAGIC) {
1612                         retval = xfs_dir2_leafn_lookup_int(blk->bp, args,
1613                                                         &blk->index, state);
1614                 } else if (blk->magic == XFS_ATTR_LEAF_MAGIC) {
1615                         retval = xfs_attr3_leaf_lookup_int(blk->bp, args);
1616                         blk->index = args->index;
1617                         args->blkno = blk->blkno;
1618                 } else {
1619                         ASSERT(0);
1620                         return -EFSCORRUPTED;
1621                 }
1622                 if (((retval == -ENOENT) || (retval == -ENOATTR)) &&
1623                     (blk->hashval == args->hashval)) {
1624                         error = xfs_da3_path_shift(state, &state->path, 1, 1,
1625                                                          &retval);
1626                         if (error)
1627                                 return error;
1628                         if (retval == 0) {
1629                                 continue;
1630                         } else if (blk->magic == XFS_ATTR_LEAF_MAGIC) {
1631                                 /* path_shift() gives ENOENT */
1632                                 retval = -ENOATTR;
1633                         }
1634                 }
1635                 break;
1636         }
1637         *result = retval;
1638         return 0;
1639 }
1640
1641 /*========================================================================
1642  * Utility routines.
1643  *========================================================================*/
1644
1645 /*
1646  * Compare two intermediate nodes for "order".
1647  */
1648 STATIC int
1649 xfs_da3_node_order(
1650         struct xfs_inode *dp,
1651         struct xfs_buf  *node1_bp,
1652         struct xfs_buf  *node2_bp)
1653 {
1654         struct xfs_da_intnode   *node1;
1655         struct xfs_da_intnode   *node2;
1656         struct xfs_da_node_entry *btree1;
1657         struct xfs_da_node_entry *btree2;
1658         struct xfs_da3_icnode_hdr node1hdr;
1659         struct xfs_da3_icnode_hdr node2hdr;
1660
1661         node1 = node1_bp->b_addr;
1662         node2 = node2_bp->b_addr;
1663         dp->d_ops->node_hdr_from_disk(&node1hdr, node1);
1664         dp->d_ops->node_hdr_from_disk(&node2hdr, node2);
1665         btree1 = dp->d_ops->node_tree_p(node1);
1666         btree2 = dp->d_ops->node_tree_p(node2);
1667
1668         if (node1hdr.count > 0 && node2hdr.count > 0 &&
1669             ((be32_to_cpu(btree2[0].hashval) < be32_to_cpu(btree1[0].hashval)) ||
1670              (be32_to_cpu(btree2[node2hdr.count - 1].hashval) <
1671               be32_to_cpu(btree1[node1hdr.count - 1].hashval)))) {
1672                 return 1;
1673         }
1674         return 0;
1675 }
1676
1677 /*
1678  * Link a new block into a doubly linked list of blocks (of whatever type).
1679  */
1680 int                                                     /* error */
1681 xfs_da3_blk_link(
1682         struct xfs_da_state     *state,
1683         struct xfs_da_state_blk *old_blk,
1684         struct xfs_da_state_blk *new_blk)
1685 {
1686         struct xfs_da_blkinfo   *old_info;
1687         struct xfs_da_blkinfo   *new_info;
1688         struct xfs_da_blkinfo   *tmp_info;
1689         struct xfs_da_args      *args;
1690         struct xfs_buf          *bp;
1691         int                     before = 0;
1692         int                     error;
1693         struct xfs_inode        *dp = state->args->dp;
1694
1695         /*
1696          * Set up environment.
1697          */
1698         args = state->args;
1699         ASSERT(args != NULL);
1700         old_info = old_blk->bp->b_addr;
1701         new_info = new_blk->bp->b_addr;
1702         ASSERT(old_blk->magic == XFS_DA_NODE_MAGIC ||
1703                old_blk->magic == XFS_DIR2_LEAFN_MAGIC ||
1704                old_blk->magic == XFS_ATTR_LEAF_MAGIC);
1705
1706         switch (old_blk->magic) {
1707         case XFS_ATTR_LEAF_MAGIC:
1708                 before = xfs_attr_leaf_order(old_blk->bp, new_blk->bp);
1709                 break;
1710         case XFS_DIR2_LEAFN_MAGIC:
1711                 before = xfs_dir2_leafn_order(dp, old_blk->bp, new_blk->bp);
1712                 break;
1713         case XFS_DA_NODE_MAGIC:
1714                 before = xfs_da3_node_order(dp, old_blk->bp, new_blk->bp);
1715                 break;
1716         }
1717
1718         /*
1719          * Link blocks in appropriate order.
1720          */
1721         if (before) {
1722                 /*
1723                  * Link new block in before existing block.
1724                  */
1725                 trace_xfs_da_link_before(args);
1726                 new_info->forw = cpu_to_be32(old_blk->blkno);
1727                 new_info->back = old_info->back;
1728                 if (old_info->back) {
1729                         error = xfs_da3_node_read(args->trans, dp,
1730                                                 be32_to_cpu(old_info->back),
1731                                                 -1, &bp, args->whichfork);
1732                         if (error)
1733                                 return error;
1734                         ASSERT(bp != NULL);
1735                         tmp_info = bp->b_addr;
1736                         ASSERT(tmp_info->magic == old_info->magic);
1737                         ASSERT(be32_to_cpu(tmp_info->forw) == old_blk->blkno);
1738                         tmp_info->forw = cpu_to_be32(new_blk->blkno);
1739                         xfs_trans_log_buf(args->trans, bp, 0, sizeof(*tmp_info)-1);
1740                 }
1741                 old_info->back = cpu_to_be32(new_blk->blkno);
1742         } else {
1743                 /*
1744                  * Link new block in after existing block.
1745                  */
1746                 trace_xfs_da_link_after(args);
1747                 new_info->forw = old_info->forw;
1748                 new_info->back = cpu_to_be32(old_blk->blkno);
1749                 if (old_info->forw) {
1750                         error = xfs_da3_node_read(args->trans, dp,
1751                                                 be32_to_cpu(old_info->forw),
1752                                                 -1, &bp, args->whichfork);
1753                         if (error)
1754                                 return error;
1755                         ASSERT(bp != NULL);
1756                         tmp_info = bp->b_addr;
1757                         ASSERT(tmp_info->magic == old_info->magic);
1758                         ASSERT(be32_to_cpu(tmp_info->back) == old_blk->blkno);
1759                         tmp_info->back = cpu_to_be32(new_blk->blkno);
1760                         xfs_trans_log_buf(args->trans, bp, 0, sizeof(*tmp_info)-1);
1761                 }
1762                 old_info->forw = cpu_to_be32(new_blk->blkno);
1763         }
1764
1765         xfs_trans_log_buf(args->trans, old_blk->bp, 0, sizeof(*tmp_info) - 1);
1766         xfs_trans_log_buf(args->trans, new_blk->bp, 0, sizeof(*tmp_info) - 1);
1767         return 0;
1768 }
1769
1770 /*
1771  * Unlink a block from a doubly linked list of blocks.
1772  */
1773 STATIC int                                              /* error */
1774 xfs_da3_blk_unlink(
1775         struct xfs_da_state     *state,
1776         struct xfs_da_state_blk *drop_blk,
1777         struct xfs_da_state_blk *save_blk)
1778 {
1779         struct xfs_da_blkinfo   *drop_info;
1780         struct xfs_da_blkinfo   *save_info;
1781         struct xfs_da_blkinfo   *tmp_info;
1782         struct xfs_da_args      *args;
1783         struct xfs_buf          *bp;
1784         int                     error;
1785
1786         /*
1787          * Set up environment.
1788          */
1789         args = state->args;
1790         ASSERT(args != NULL);
1791         save_info = save_blk->bp->b_addr;
1792         drop_info = drop_blk->bp->b_addr;
1793         ASSERT(save_blk->magic == XFS_DA_NODE_MAGIC ||
1794                save_blk->magic == XFS_DIR2_LEAFN_MAGIC ||
1795                save_blk->magic == XFS_ATTR_LEAF_MAGIC);
1796         ASSERT(save_blk->magic == drop_blk->magic);
1797         ASSERT((be32_to_cpu(save_info->forw) == drop_blk->blkno) ||
1798                (be32_to_cpu(save_info->back) == drop_blk->blkno));
1799         ASSERT((be32_to_cpu(drop_info->forw) == save_blk->blkno) ||
1800                (be32_to_cpu(drop_info->back) == save_blk->blkno));
1801
1802         /*
1803          * Unlink the leaf block from the doubly linked chain of leaves.
1804          */
1805         if (be32_to_cpu(save_info->back) == drop_blk->blkno) {
1806                 trace_xfs_da_unlink_back(args);
1807                 save_info->back = drop_info->back;
1808                 if (drop_info->back) {
1809                         error = xfs_da3_node_read(args->trans, args->dp,
1810                                                 be32_to_cpu(drop_info->back),
1811                                                 -1, &bp, args->whichfork);
1812                         if (error)
1813                                 return error;
1814                         ASSERT(bp != NULL);
1815                         tmp_info = bp->b_addr;
1816                         ASSERT(tmp_info->magic == save_info->magic);
1817                         ASSERT(be32_to_cpu(tmp_info->forw) == drop_blk->blkno);
1818                         tmp_info->forw = cpu_to_be32(save_blk->blkno);
1819                         xfs_trans_log_buf(args->trans, bp, 0,
1820                                                     sizeof(*tmp_info) - 1);
1821                 }
1822         } else {
1823                 trace_xfs_da_unlink_forward(args);
1824                 save_info->forw = drop_info->forw;
1825                 if (drop_info->forw) {
1826                         error = xfs_da3_node_read(args->trans, args->dp,
1827                                                 be32_to_cpu(drop_info->forw),
1828                                                 -1, &bp, args->whichfork);
1829                         if (error)
1830                                 return error;
1831                         ASSERT(bp != NULL);
1832                         tmp_info = bp->b_addr;
1833                         ASSERT(tmp_info->magic == save_info->magic);
1834                         ASSERT(be32_to_cpu(tmp_info->back) == drop_blk->blkno);
1835                         tmp_info->back = cpu_to_be32(save_blk->blkno);
1836                         xfs_trans_log_buf(args->trans, bp, 0,
1837                                                     sizeof(*tmp_info) - 1);
1838                 }
1839         }
1840
1841         xfs_trans_log_buf(args->trans, save_blk->bp, 0, sizeof(*save_info) - 1);
1842         return 0;
1843 }
1844
1845 /*
1846  * Move a path "forward" or "!forward" one block at the current level.
1847  *
1848  * This routine will adjust a "path" to point to the next block
1849  * "forward" (higher hashvalues) or "!forward" (lower hashvals) in the
1850  * Btree, including updating pointers to the intermediate nodes between
1851  * the new bottom and the root.
1852  */
1853 int                                                     /* error */
1854 xfs_da3_path_shift(
1855         struct xfs_da_state     *state,
1856         struct xfs_da_state_path *path,
1857         int                     forward,
1858         int                     release,
1859         int                     *result)
1860 {
1861         struct xfs_da_state_blk *blk;
1862         struct xfs_da_blkinfo   *info;
1863         struct xfs_da_intnode   *node;
1864         struct xfs_da_args      *args;
1865         struct xfs_da_node_entry *btree;
1866         struct xfs_da3_icnode_hdr nodehdr;
1867         struct xfs_buf          *bp;
1868         xfs_dablk_t             blkno = 0;
1869         int                     level;
1870         int                     error;
1871         struct xfs_inode        *dp = state->args->dp;
1872
1873         trace_xfs_da_path_shift(state->args);
1874
1875         /*
1876          * Roll up the Btree looking for the first block where our
1877          * current index is not at the edge of the block.  Note that
1878          * we skip the bottom layer because we want the sibling block.
1879          */
1880         args = state->args;
1881         ASSERT(args != NULL);
1882         ASSERT(path != NULL);
1883         ASSERT((path->active > 0) && (path->active < XFS_DA_NODE_MAXDEPTH));
1884         level = (path->active-1) - 1;   /* skip bottom layer in path */
1885         for (blk = &path->blk[level]; level >= 0; blk--, level--) {
1886                 node = blk->bp->b_addr;
1887                 dp->d_ops->node_hdr_from_disk(&nodehdr, node);
1888                 btree = dp->d_ops->node_tree_p(node);
1889
1890                 if (forward && (blk->index < nodehdr.count - 1)) {
1891                         blk->index++;
1892                         blkno = be32_to_cpu(btree[blk->index].before);
1893                         break;
1894                 } else if (!forward && (blk->index > 0)) {
1895                         blk->index--;
1896                         blkno = be32_to_cpu(btree[blk->index].before);
1897                         break;
1898                 }
1899         }
1900         if (level < 0) {
1901                 *result = -ENOENT;      /* we're out of our tree */
1902                 ASSERT(args->op_flags & XFS_DA_OP_OKNOENT);
1903                 return 0;
1904         }
1905
1906         /*
1907          * Roll down the edge of the subtree until we reach the
1908          * same depth we were at originally.
1909          */
1910         for (blk++, level++; level < path->active; blk++, level++) {
1911                 /*
1912                  * Read the next child block into a local buffer.
1913                  */
1914                 error = xfs_da3_node_read(args->trans, dp, blkno, -1, &bp,
1915                                           args->whichfork);
1916                 if (error)
1917                         return error;
1918
1919                 /*
1920                  * Release the old block (if it's dirty, the trans doesn't
1921                  * actually let go) and swap the local buffer into the path
1922                  * structure. This ensures failure of the above read doesn't set
1923                  * a NULL buffer in an active slot in the path.
1924                  */
1925                 if (release)
1926                         xfs_trans_brelse(args->trans, blk->bp);
1927                 blk->blkno = blkno;
1928                 blk->bp = bp;
1929
1930                 info = blk->bp->b_addr;
1931                 ASSERT(info->magic == cpu_to_be16(XFS_DA_NODE_MAGIC) ||
1932                        info->magic == cpu_to_be16(XFS_DA3_NODE_MAGIC) ||
1933                        info->magic == cpu_to_be16(XFS_DIR2_LEAFN_MAGIC) ||
1934                        info->magic == cpu_to_be16(XFS_DIR3_LEAFN_MAGIC) ||
1935                        info->magic == cpu_to_be16(XFS_ATTR_LEAF_MAGIC) ||
1936                        info->magic == cpu_to_be16(XFS_ATTR3_LEAF_MAGIC));
1937
1938
1939                 /*
1940                  * Note: we flatten the magic number to a single type so we
1941                  * don't have to compare against crc/non-crc types elsewhere.
1942                  */
1943                 switch (be16_to_cpu(info->magic)) {
1944                 case XFS_DA_NODE_MAGIC:
1945                 case XFS_DA3_NODE_MAGIC:
1946                         blk->magic = XFS_DA_NODE_MAGIC;
1947                         node = (xfs_da_intnode_t *)info;
1948                         dp->d_ops->node_hdr_from_disk(&nodehdr, node);
1949                         btree = dp->d_ops->node_tree_p(node);
1950                         blk->hashval = be32_to_cpu(btree[nodehdr.count - 1].hashval);
1951                         if (forward)
1952                                 blk->index = 0;
1953                         else
1954                                 blk->index = nodehdr.count - 1;
1955                         blkno = be32_to_cpu(btree[blk->index].before);
1956                         break;
1957                 case XFS_ATTR_LEAF_MAGIC:
1958                 case XFS_ATTR3_LEAF_MAGIC:
1959                         blk->magic = XFS_ATTR_LEAF_MAGIC;
1960                         ASSERT(level == path->active-1);
1961                         blk->index = 0;
1962                         blk->hashval = xfs_attr_leaf_lasthash(blk->bp, NULL);
1963                         break;
1964                 case XFS_DIR2_LEAFN_MAGIC:
1965                 case XFS_DIR3_LEAFN_MAGIC:
1966                         blk->magic = XFS_DIR2_LEAFN_MAGIC;
1967                         ASSERT(level == path->active-1);
1968                         blk->index = 0;
1969                         blk->hashval = xfs_dir2_leaf_lasthash(args->dp,
1970                                                               blk->bp, NULL);
1971                         break;
1972                 default:
1973                         ASSERT(0);
1974                         break;
1975                 }
1976         }
1977         *result = 0;
1978         return 0;
1979 }
1980
1981
1982 /*========================================================================
1983  * Utility routines.
1984  *========================================================================*/
1985
1986 /*
1987  * Implement a simple hash on a character string.
1988  * Rotate the hash value by 7 bits, then XOR each character in.
1989  * This is implemented with some source-level loop unrolling.
1990  */
1991 xfs_dahash_t
1992 xfs_da_hashname(const uint8_t *name, int namelen)
1993 {
1994         xfs_dahash_t hash;
1995
1996         /*
1997          * Do four characters at a time as long as we can.
1998          */
1999         for (hash = 0; namelen >= 4; namelen -= 4, name += 4)
2000                 hash = (name[0] << 21) ^ (name[1] << 14) ^ (name[2] << 7) ^
2001                        (name[3] << 0) ^ rol32(hash, 7 * 4);
2002
2003         /*
2004          * Now do the rest of the characters.
2005          */
2006         switch (namelen) {
2007         case 3:
2008                 return (name[0] << 14) ^ (name[1] << 7) ^ (name[2] << 0) ^
2009                        rol32(hash, 7 * 3);
2010         case 2:
2011                 return (name[0] << 7) ^ (name[1] << 0) ^ rol32(hash, 7 * 2);
2012         case 1:
2013                 return (name[0] << 0) ^ rol32(hash, 7 * 1);
2014         default: /* case 0: */
2015                 return hash;
2016         }
2017 }
2018
2019 enum xfs_dacmp
2020 xfs_da_compname(
2021         struct xfs_da_args *args,
2022         const unsigned char *name,
2023         int             len)
2024 {
2025         return (args->namelen == len && memcmp(args->name, name, len) == 0) ?
2026                                         XFS_CMP_EXACT : XFS_CMP_DIFFERENT;
2027 }
2028
2029 static xfs_dahash_t
2030 xfs_default_hashname(
2031         struct xfs_name *name)
2032 {
2033         return xfs_da_hashname(name->name, name->len);
2034 }
2035
2036 const struct xfs_nameops xfs_default_nameops = {
2037         .hashname       = xfs_default_hashname,
2038         .compname       = xfs_da_compname
2039 };
2040
2041 int
2042 xfs_da_grow_inode_int(
2043         struct xfs_da_args      *args,
2044         xfs_fileoff_t           *bno,
2045         int                     count)
2046 {
2047         struct xfs_trans        *tp = args->trans;
2048         struct xfs_inode        *dp = args->dp;
2049         int                     w = args->whichfork;
2050         xfs_rfsblock_t          nblks = dp->i_d.di_nblocks;
2051         struct xfs_bmbt_irec    map, *mapp;
2052         int                     nmap, error, got, i, mapi;
2053
2054         /*
2055          * Find a spot in the file space to put the new block.
2056          */
2057         error = xfs_bmap_first_unused(tp, dp, count, bno, w);
2058         if (error)
2059                 return error;
2060
2061         /*
2062          * Try mapping it in one filesystem block.
2063          */
2064         nmap = 1;
2065         error = xfs_bmapi_write(tp, dp, *bno, count,
2066                         xfs_bmapi_aflag(w)|XFS_BMAPI_METADATA|XFS_BMAPI_CONTIG,
2067                         args->total, &map, &nmap);
2068         if (error)
2069                 return error;
2070
2071         ASSERT(nmap <= 1);
2072         if (nmap == 1) {
2073                 mapp = &map;
2074                 mapi = 1;
2075         } else if (nmap == 0 && count > 1) {
2076                 xfs_fileoff_t           b;
2077                 int                     c;
2078
2079                 /*
2080                  * If we didn't get it and the block might work if fragmented,
2081                  * try without the CONTIG flag.  Loop until we get it all.
2082                  */
2083                 mapp = kmem_alloc(sizeof(*mapp) * count, KM_SLEEP);
2084                 for (b = *bno, mapi = 0; b < *bno + count; ) {
2085                         nmap = min(XFS_BMAP_MAX_NMAP, count);
2086                         c = (int)(*bno + count - b);
2087                         error = xfs_bmapi_write(tp, dp, b, c,
2088                                         xfs_bmapi_aflag(w)|XFS_BMAPI_METADATA,
2089                                         args->total, &mapp[mapi], &nmap);
2090                         if (error)
2091                                 goto out_free_map;
2092                         if (nmap < 1)
2093                                 break;
2094                         mapi += nmap;
2095                         b = mapp[mapi - 1].br_startoff +
2096                             mapp[mapi - 1].br_blockcount;
2097                 }
2098         } else {
2099                 mapi = 0;
2100                 mapp = NULL;
2101         }
2102
2103         /*
2104          * Count the blocks we got, make sure it matches the total.
2105          */
2106         for (i = 0, got = 0; i < mapi; i++)
2107                 got += mapp[i].br_blockcount;
2108         if (got != count || mapp[0].br_startoff != *bno ||
2109             mapp[mapi - 1].br_startoff + mapp[mapi - 1].br_blockcount !=
2110             *bno + count) {
2111                 error = -ENOSPC;
2112                 goto out_free_map;
2113         }
2114
2115         /* account for newly allocated blocks in reserved blocks total */
2116         args->total -= dp->i_d.di_nblocks - nblks;
2117
2118 out_free_map:
2119         if (mapp != &map)
2120                 kmem_free(mapp);
2121         return error;
2122 }
2123
2124 /*
2125  * Add a block to the btree ahead of the file.
2126  * Return the new block number to the caller.
2127  */
2128 int
2129 xfs_da_grow_inode(
2130         struct xfs_da_args      *args,
2131         xfs_dablk_t             *new_blkno)
2132 {
2133         xfs_fileoff_t           bno;
2134         int                     error;
2135
2136         trace_xfs_da_grow_inode(args);
2137
2138         bno = args->geo->leafblk;
2139         error = xfs_da_grow_inode_int(args, &bno, args->geo->fsbcount);
2140         if (!error)
2141                 *new_blkno = (xfs_dablk_t)bno;
2142         return error;
2143 }
2144
2145 /*
2146  * Ick.  We need to always be able to remove a btree block, even
2147  * if there's no space reservation because the filesystem is full.
2148  * This is called if xfs_bunmapi on a btree block fails due to ENOSPC.
2149  * It swaps the target block with the last block in the file.  The
2150  * last block in the file can always be removed since it can't cause
2151  * a bmap btree split to do that.
2152  */
2153 STATIC int
2154 xfs_da3_swap_lastblock(
2155         struct xfs_da_args      *args,
2156         xfs_dablk_t             *dead_blknop,
2157         struct xfs_buf          **dead_bufp)
2158 {
2159         struct xfs_da_blkinfo   *dead_info;
2160         struct xfs_da_blkinfo   *sib_info;
2161         struct xfs_da_intnode   *par_node;
2162         struct xfs_da_intnode   *dead_node;
2163         struct xfs_dir2_leaf    *dead_leaf2;
2164         struct xfs_da_node_entry *btree;
2165         struct xfs_da3_icnode_hdr par_hdr;
2166         struct xfs_inode        *dp;
2167         struct xfs_trans        *tp;
2168         struct xfs_mount        *mp;
2169         struct xfs_buf          *dead_buf;
2170         struct xfs_buf          *last_buf;
2171         struct xfs_buf          *sib_buf;
2172         struct xfs_buf          *par_buf;
2173         xfs_dahash_t            dead_hash;
2174         xfs_fileoff_t           lastoff;
2175         xfs_dablk_t             dead_blkno;
2176         xfs_dablk_t             last_blkno;
2177         xfs_dablk_t             sib_blkno;
2178         xfs_dablk_t             par_blkno;
2179         int                     error;
2180         int                     w;
2181         int                     entno;
2182         int                     level;
2183         int                     dead_level;
2184
2185         trace_xfs_da_swap_lastblock(args);
2186
2187         dead_buf = *dead_bufp;
2188         dead_blkno = *dead_blknop;
2189         tp = args->trans;
2190         dp = args->dp;
2191         w = args->whichfork;
2192         ASSERT(w == XFS_DATA_FORK);
2193         mp = dp->i_mount;
2194         lastoff = args->geo->freeblk;
2195         error = xfs_bmap_last_before(tp, dp, &lastoff, w);
2196         if (error)
2197                 return error;
2198         if (unlikely(lastoff == 0)) {
2199                 XFS_ERROR_REPORT("xfs_da_swap_lastblock(1)", XFS_ERRLEVEL_LOW,
2200                                  mp);
2201                 return -EFSCORRUPTED;
2202         }
2203         /*
2204          * Read the last block in the btree space.
2205          */
2206         last_blkno = (xfs_dablk_t)lastoff - args->geo->fsbcount;
2207         error = xfs_da3_node_read(tp, dp, last_blkno, -1, &last_buf, w);
2208         if (error)
2209                 return error;
2210         /*
2211          * Copy the last block into the dead buffer and log it.
2212          */
2213         memcpy(dead_buf->b_addr, last_buf->b_addr, args->geo->blksize);
2214         xfs_trans_log_buf(tp, dead_buf, 0, args->geo->blksize - 1);
2215         dead_info = dead_buf->b_addr;
2216         /*
2217          * Get values from the moved block.
2218          */
2219         if (dead_info->magic == cpu_to_be16(XFS_DIR2_LEAFN_MAGIC) ||
2220             dead_info->magic == cpu_to_be16(XFS_DIR3_LEAFN_MAGIC)) {
2221                 struct xfs_dir3_icleaf_hdr leafhdr;
2222                 struct xfs_dir2_leaf_entry *ents;
2223
2224                 dead_leaf2 = (xfs_dir2_leaf_t *)dead_info;
2225                 dp->d_ops->leaf_hdr_from_disk(&leafhdr, dead_leaf2);
2226                 ents = dp->d_ops->leaf_ents_p(dead_leaf2);
2227                 dead_level = 0;
2228                 dead_hash = be32_to_cpu(ents[leafhdr.count - 1].hashval);
2229         } else {
2230                 struct xfs_da3_icnode_hdr deadhdr;
2231
2232                 dead_node = (xfs_da_intnode_t *)dead_info;
2233                 dp->d_ops->node_hdr_from_disk(&deadhdr, dead_node);
2234                 btree = dp->d_ops->node_tree_p(dead_node);
2235                 dead_level = deadhdr.level;
2236                 dead_hash = be32_to_cpu(btree[deadhdr.count - 1].hashval);
2237         }
2238         sib_buf = par_buf = NULL;
2239         /*
2240          * If the moved block has a left sibling, fix up the pointers.
2241          */
2242         if ((sib_blkno = be32_to_cpu(dead_info->back))) {
2243                 error = xfs_da3_node_read(tp, dp, sib_blkno, -1, &sib_buf, w);
2244                 if (error)
2245                         goto done;
2246                 sib_info = sib_buf->b_addr;
2247                 if (unlikely(
2248                     be32_to_cpu(sib_info->forw) != last_blkno ||
2249                     sib_info->magic != dead_info->magic)) {
2250                         XFS_ERROR_REPORT("xfs_da_swap_lastblock(2)",
2251                                          XFS_ERRLEVEL_LOW, mp);
2252                         error = -EFSCORRUPTED;
2253                         goto done;
2254                 }
2255                 sib_info->forw = cpu_to_be32(dead_blkno);
2256                 xfs_trans_log_buf(tp, sib_buf,
2257                         XFS_DA_LOGRANGE(sib_info, &sib_info->forw,
2258                                         sizeof(sib_info->forw)));
2259                 sib_buf = NULL;
2260         }
2261         /*
2262          * If the moved block has a right sibling, fix up the pointers.
2263          */
2264         if ((sib_blkno = be32_to_cpu(dead_info->forw))) {
2265                 error = xfs_da3_node_read(tp, dp, sib_blkno, -1, &sib_buf, w);
2266                 if (error)
2267                         goto done;
2268                 sib_info = sib_buf->b_addr;
2269                 if (unlikely(
2270                        be32_to_cpu(sib_info->back) != last_blkno ||
2271                        sib_info->magic != dead_info->magic)) {
2272                         XFS_ERROR_REPORT("xfs_da_swap_lastblock(3)",
2273                                          XFS_ERRLEVEL_LOW, mp);
2274                         error = -EFSCORRUPTED;
2275                         goto done;
2276                 }
2277                 sib_info->back = cpu_to_be32(dead_blkno);
2278                 xfs_trans_log_buf(tp, sib_buf,
2279                         XFS_DA_LOGRANGE(sib_info, &sib_info->back,
2280                                         sizeof(sib_info->back)));
2281                 sib_buf = NULL;
2282         }
2283         par_blkno = args->geo->leafblk;
2284         level = -1;
2285         /*
2286          * Walk down the tree looking for the parent of the moved block.
2287          */
2288         for (;;) {
2289                 error = xfs_da3_node_read(tp, dp, par_blkno, -1, &par_buf, w);
2290                 if (error)
2291                         goto done;
2292                 par_node = par_buf->b_addr;
2293                 dp->d_ops->node_hdr_from_disk(&par_hdr, par_node);
2294                 if (level >= 0 && level != par_hdr.level + 1) {
2295                         XFS_ERROR_REPORT("xfs_da_swap_lastblock(4)",
2296                                          XFS_ERRLEVEL_LOW, mp);
2297                         error = -EFSCORRUPTED;
2298                         goto done;
2299                 }
2300                 level = par_hdr.level;
2301                 btree = dp->d_ops->node_tree_p(par_node);
2302                 for (entno = 0;
2303                      entno < par_hdr.count &&
2304                      be32_to_cpu(btree[entno].hashval) < dead_hash;
2305                      entno++)
2306                         continue;
2307                 if (entno == par_hdr.count) {
2308                         XFS_ERROR_REPORT("xfs_da_swap_lastblock(5)",
2309                                          XFS_ERRLEVEL_LOW, mp);
2310                         error = -EFSCORRUPTED;
2311                         goto done;
2312                 }
2313                 par_blkno = be32_to_cpu(btree[entno].before);
2314                 if (level == dead_level + 1)
2315                         break;
2316                 xfs_trans_brelse(tp, par_buf);
2317                 par_buf = NULL;
2318         }
2319         /*
2320          * We're in the right parent block.
2321          * Look for the right entry.
2322          */
2323         for (;;) {
2324                 for (;
2325                      entno < par_hdr.count &&
2326                      be32_to_cpu(btree[entno].before) != last_blkno;
2327                      entno++)
2328                         continue;
2329                 if (entno < par_hdr.count)
2330                         break;
2331                 par_blkno = par_hdr.forw;
2332                 xfs_trans_brelse(tp, par_buf);
2333                 par_buf = NULL;
2334                 if (unlikely(par_blkno == 0)) {
2335                         XFS_ERROR_REPORT("xfs_da_swap_lastblock(6)",
2336                                          XFS_ERRLEVEL_LOW, mp);
2337                         error = -EFSCORRUPTED;
2338                         goto done;
2339                 }
2340                 error = xfs_da3_node_read(tp, dp, par_blkno, -1, &par_buf, w);
2341                 if (error)
2342                         goto done;
2343                 par_node = par_buf->b_addr;
2344                 dp->d_ops->node_hdr_from_disk(&par_hdr, par_node);
2345                 if (par_hdr.level != level) {
2346                         XFS_ERROR_REPORT("xfs_da_swap_lastblock(7)",
2347                                          XFS_ERRLEVEL_LOW, mp);
2348                         error = -EFSCORRUPTED;
2349                         goto done;
2350                 }
2351                 btree = dp->d_ops->node_tree_p(par_node);
2352                 entno = 0;
2353         }
2354         /*
2355          * Update the parent entry pointing to the moved block.
2356          */
2357         btree[entno].before = cpu_to_be32(dead_blkno);
2358         xfs_trans_log_buf(tp, par_buf,
2359                 XFS_DA_LOGRANGE(par_node, &btree[entno].before,
2360                                 sizeof(btree[entno].before)));
2361         *dead_blknop = last_blkno;
2362         *dead_bufp = last_buf;
2363         return 0;
2364 done:
2365         if (par_buf)
2366                 xfs_trans_brelse(tp, par_buf);
2367         if (sib_buf)
2368                 xfs_trans_brelse(tp, sib_buf);
2369         xfs_trans_brelse(tp, last_buf);
2370         return error;
2371 }
2372
2373 /*
2374  * Remove a btree block from a directory or attribute.
2375  */
2376 int
2377 xfs_da_shrink_inode(
2378         struct xfs_da_args      *args,
2379         xfs_dablk_t             dead_blkno,
2380         struct xfs_buf          *dead_buf)
2381 {
2382         struct xfs_inode        *dp;
2383         int                     done, error, w, count;
2384         struct xfs_trans        *tp;
2385
2386         trace_xfs_da_shrink_inode(args);
2387
2388         dp = args->dp;
2389         w = args->whichfork;
2390         tp = args->trans;
2391         count = args->geo->fsbcount;
2392         for (;;) {
2393                 /*
2394                  * Remove extents.  If we get ENOSPC for a dir we have to move
2395                  * the last block to the place we want to kill.
2396                  */
2397                 error = xfs_bunmapi(tp, dp, dead_blkno, count,
2398                                     xfs_bmapi_aflag(w), 0, &done);
2399                 if (error == -ENOSPC) {
2400                         if (w != XFS_DATA_FORK)
2401                                 break;
2402                         error = xfs_da3_swap_lastblock(args, &dead_blkno,
2403                                                       &dead_buf);
2404                         if (error)
2405                                 break;
2406                 } else {
2407                         break;
2408                 }
2409         }
2410         xfs_trans_binval(tp, dead_buf);
2411         return error;
2412 }
2413
2414 /*
2415  * See if the mapping(s) for this btree block are valid, i.e.
2416  * don't contain holes, are logically contiguous, and cover the whole range.
2417  */
2418 STATIC int
2419 xfs_da_map_covers_blocks(
2420         int             nmap,
2421         xfs_bmbt_irec_t *mapp,
2422         xfs_dablk_t     bno,
2423         int             count)
2424 {
2425         int             i;
2426         xfs_fileoff_t   off;
2427
2428         for (i = 0, off = bno; i < nmap; i++) {
2429                 if (mapp[i].br_startblock == HOLESTARTBLOCK ||
2430                     mapp[i].br_startblock == DELAYSTARTBLOCK) {
2431                         return 0;
2432                 }
2433                 if (off != mapp[i].br_startoff) {
2434                         return 0;
2435                 }
2436                 off += mapp[i].br_blockcount;
2437         }
2438         return off == bno + count;
2439 }
2440
2441 /*
2442  * Convert a struct xfs_bmbt_irec to a struct xfs_buf_map.
2443  *
2444  * For the single map case, it is assumed that the caller has provided a pointer
2445  * to a valid xfs_buf_map.  For the multiple map case, this function will
2446  * allocate the xfs_buf_map to hold all the maps and replace the caller's single
2447  * map pointer with the allocated map.
2448  */
2449 static int
2450 xfs_buf_map_from_irec(
2451         struct xfs_mount        *mp,
2452         struct xfs_buf_map      **mapp,
2453         int                     *nmaps,
2454         struct xfs_bmbt_irec    *irecs,
2455         int                     nirecs)
2456 {
2457         struct xfs_buf_map      *map;
2458         int                     i;
2459
2460         ASSERT(*nmaps == 1);
2461         ASSERT(nirecs >= 1);
2462
2463         if (nirecs > 1) {
2464                 map = kmem_zalloc(nirecs * sizeof(struct xfs_buf_map),
2465                                   KM_SLEEP | KM_NOFS);
2466                 if (!map)
2467                         return -ENOMEM;
2468                 *mapp = map;
2469         }
2470
2471         *nmaps = nirecs;
2472         map = *mapp;
2473         for (i = 0; i < *nmaps; i++) {
2474                 ASSERT(irecs[i].br_startblock != DELAYSTARTBLOCK &&
2475                        irecs[i].br_startblock != HOLESTARTBLOCK);
2476                 map[i].bm_bn = XFS_FSB_TO_DADDR(mp, irecs[i].br_startblock);
2477                 map[i].bm_len = XFS_FSB_TO_BB(mp, irecs[i].br_blockcount);
2478         }
2479         return 0;
2480 }
2481
2482 /*
2483  * Map the block we are given ready for reading. There are three possible return
2484  * values:
2485  *      -1 - will be returned if we land in a hole and mappedbno == -2 so the
2486  *           caller knows not to execute a subsequent read.
2487  *       0 - if we mapped the block successfully
2488  *      >0 - positive error number if there was an error.
2489  */
2490 static int
2491 xfs_dabuf_map(
2492         struct xfs_inode        *dp,
2493         xfs_dablk_t             bno,
2494         xfs_daddr_t             mappedbno,
2495         int                     whichfork,
2496         struct xfs_buf_map      **map,
2497         int                     *nmaps)
2498 {
2499         struct xfs_mount        *mp = dp->i_mount;
2500         int                     nfsb;
2501         int                     error = 0;
2502         struct xfs_bmbt_irec    irec;
2503         struct xfs_bmbt_irec    *irecs = &irec;
2504         int                     nirecs;
2505
2506         ASSERT(map && *map);
2507         ASSERT(*nmaps == 1);
2508
2509         if (whichfork == XFS_DATA_FORK)
2510                 nfsb = mp->m_dir_geo->fsbcount;
2511         else
2512                 nfsb = mp->m_attr_geo->fsbcount;
2513
2514         /*
2515          * Caller doesn't have a mapping.  -2 means don't complain
2516          * if we land in a hole.
2517          */
2518         if (mappedbno == -1 || mappedbno == -2) {
2519                 /*
2520                  * Optimize the one-block case.
2521                  */
2522                 if (nfsb != 1)
2523                         irecs = kmem_zalloc(sizeof(irec) * nfsb,
2524                                             KM_SLEEP | KM_NOFS);
2525
2526                 nirecs = nfsb;
2527                 error = xfs_bmapi_read(dp, (xfs_fileoff_t)bno, nfsb, irecs,
2528                                        &nirecs, xfs_bmapi_aflag(whichfork));
2529                 if (error)
2530                         goto out;
2531         } else {
2532                 irecs->br_startblock = XFS_DADDR_TO_FSB(mp, mappedbno);
2533                 irecs->br_startoff = (xfs_fileoff_t)bno;
2534                 irecs->br_blockcount = nfsb;
2535                 irecs->br_state = 0;
2536                 nirecs = 1;
2537         }
2538
2539         if (!xfs_da_map_covers_blocks(nirecs, irecs, bno, nfsb)) {
2540                 error = mappedbno == -2 ? -1 : -EFSCORRUPTED;
2541                 if (unlikely(error == -EFSCORRUPTED)) {
2542                         if (xfs_error_level >= XFS_ERRLEVEL_LOW) {
2543                                 int i;
2544                                 xfs_alert(mp, "%s: bno %lld dir: inode %lld",
2545                                         __func__, (long long)bno,
2546                                         (long long)dp->i_ino);
2547                                 for (i = 0; i < *nmaps; i++) {
2548                                         xfs_alert(mp,
2549 "[%02d] br_startoff %lld br_startblock %lld br_blockcount %lld br_state %d",
2550                                                 i,
2551                                                 (long long)irecs[i].br_startoff,
2552                                                 (long long)irecs[i].br_startblock,
2553                                                 (long long)irecs[i].br_blockcount,
2554                                                 irecs[i].br_state);
2555                                 }
2556                         }
2557                         XFS_ERROR_REPORT("xfs_da_do_buf(1)",
2558                                          XFS_ERRLEVEL_LOW, mp);
2559                 }
2560                 goto out;
2561         }
2562         error = xfs_buf_map_from_irec(mp, map, nmaps, irecs, nirecs);
2563 out:
2564         if (irecs != &irec)
2565                 kmem_free(irecs);
2566         return error;
2567 }
2568
2569 /*
2570  * Get a buffer for the dir/attr block.
2571  */
2572 int
2573 xfs_da_get_buf(
2574         struct xfs_trans        *trans,
2575         struct xfs_inode        *dp,
2576         xfs_dablk_t             bno,
2577         xfs_daddr_t             mappedbno,
2578         struct xfs_buf          **bpp,
2579         int                     whichfork)
2580 {
2581         struct xfs_buf          *bp;
2582         struct xfs_buf_map      map;
2583         struct xfs_buf_map      *mapp;
2584         int                     nmap;
2585         int                     error;
2586
2587         *bpp = NULL;
2588         mapp = &map;
2589         nmap = 1;
2590         error = xfs_dabuf_map(dp, bno, mappedbno, whichfork,
2591                                 &mapp, &nmap);
2592         if (error) {
2593                 /* mapping a hole is not an error, but we don't continue */
2594                 if (error == -1)
2595                         error = 0;
2596                 goto out_free;
2597         }
2598
2599         bp = xfs_trans_get_buf_map(trans, dp->i_mount->m_ddev_targp,
2600                                     mapp, nmap, 0);
2601         error = bp ? bp->b_error : -EIO;
2602         if (error) {
2603                 if (bp)
2604                         xfs_trans_brelse(trans, bp);
2605                 goto out_free;
2606         }
2607
2608         *bpp = bp;
2609
2610 out_free:
2611         if (mapp != &map)
2612                 kmem_free(mapp);
2613
2614         return error;
2615 }
2616
2617 /*
2618  * Get a buffer for the dir/attr block, fill in the contents.
2619  */
2620 int
2621 xfs_da_read_buf(
2622         struct xfs_trans        *trans,
2623         struct xfs_inode        *dp,
2624         xfs_dablk_t             bno,
2625         xfs_daddr_t             mappedbno,
2626         struct xfs_buf          **bpp,
2627         int                     whichfork,
2628         const struct xfs_buf_ops *ops)
2629 {
2630         struct xfs_buf          *bp;
2631         struct xfs_buf_map      map;
2632         struct xfs_buf_map      *mapp;
2633         int                     nmap;
2634         int                     error;
2635
2636         *bpp = NULL;
2637         mapp = &map;
2638         nmap = 1;
2639         error = xfs_dabuf_map(dp, bno, mappedbno, whichfork,
2640                                 &mapp, &nmap);
2641         if (error) {
2642                 /* mapping a hole is not an error, but we don't continue */
2643                 if (error == -1)
2644                         error = 0;
2645                 goto out_free;
2646         }
2647
2648         error = xfs_trans_read_buf_map(dp->i_mount, trans,
2649                                         dp->i_mount->m_ddev_targp,
2650                                         mapp, nmap, 0, &bp, ops);
2651         if (error)
2652                 goto out_free;
2653
2654         if (whichfork == XFS_ATTR_FORK)
2655                 xfs_buf_set_ref(bp, XFS_ATTR_BTREE_REF);
2656         else
2657                 xfs_buf_set_ref(bp, XFS_DIR_BTREE_REF);
2658         *bpp = bp;
2659 out_free:
2660         if (mapp != &map)
2661                 kmem_free(mapp);
2662
2663         return error;
2664 }
2665
2666 /*
2667  * Readahead the dir/attr block.
2668  */
2669 int
2670 xfs_da_reada_buf(
2671         struct xfs_inode        *dp,
2672         xfs_dablk_t             bno,
2673         xfs_daddr_t             mappedbno,
2674         int                     whichfork,
2675         const struct xfs_buf_ops *ops)
2676 {
2677         struct xfs_buf_map      map;
2678         struct xfs_buf_map      *mapp;
2679         int                     nmap;
2680         int                     error;
2681
2682         mapp = &map;
2683         nmap = 1;
2684         error = xfs_dabuf_map(dp, bno, mappedbno, whichfork,
2685                                 &mapp, &nmap);
2686         if (error) {
2687                 /* mapping a hole is not an error, but we don't continue */
2688                 if (error == -1)
2689                         error = 0;
2690                 goto out_free;
2691         }
2692
2693         mappedbno = mapp[0].bm_bn;
2694         xfs_buf_readahead_map(dp->i_mount->m_ddev_targp, mapp, nmap, ops);
2695
2696 out_free:
2697         if (mapp != &map)
2698                 kmem_free(mapp);
2699
2700         return error;
2701 }