fs/xfs/xfs_dir2_data.c

   1 /*
   2  * Copyright (c) 2000-2002,2005 Silicon Graphics, Inc.
   3  * All Rights Reserved.
   4  *
   5  * This program is free software; you can redistribute it and/or
   6  * modify it under the terms of the GNU General Public License as
   7  * published by the Free Software Foundation.
   8  *
   9  * This program is distributed in the hope that it would be useful,
  10  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  11  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  12  * GNU General Public License for more details.
  13  *
  14  * You should have received a copy of the GNU General Public License
  15  * along with this program; if not, write the Free Software Foundation,
  16  * Inc.,  51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
  17  */
  18 #include "xfs.h"
  19 #include "xfs_fs.h"
  20 #include "xfs_types.h"
  21 #include "xfs_log.h"
  22 #include "xfs_inum.h"
  23 #include "xfs_trans.h"
  24 #include "xfs_sb.h"
  25 #include "xfs_ag.h"
  26 #include "xfs_dir2.h"
  27 #include "xfs_dmapi.h"
  28 #include "xfs_mount.h"
  29 #include "xfs_da_btree.h"
  30 #include "xfs_bmap_btree.h"
  31 #include "xfs_dir2_sf.h"
  32 #include "xfs_attr_sf.h"
  33 #include "xfs_dinode.h"
  34 #include "xfs_inode.h"
  35 #include "xfs_dir2_data.h"
  36 #include "xfs_dir2_leaf.h"
  37 #include "xfs_dir2_block.h"
  38 #include "xfs_error.h"
  39
  40 #ifdef DEBUG
  41 /*
  42  * Check the consistency of the data block.
  43  * The input can also be a block-format directory.
  44  * Pop an assert if we find anything bad.
  45  */
  46 void
  47 xfs_dir2_data_check(
  48         xfs_inode_t             *dp,            /* incore inode pointer */
  49         xfs_dabuf_t             *bp)            /* data block's buffer */
  50 {
  51         xfs_dir2_dataptr_t      addr;           /* addr for leaf lookup */
  52         xfs_dir2_data_free_t    *bf;            /* bestfree table */
  53         xfs_dir2_block_tail_t   *btp=NULL;      /* block tail */
  54         int                     count;          /* count of entries found */
  55         xfs_dir2_data_t         *d;             /* data block pointer */
  56         xfs_dir2_data_entry_t   *dep;           /* data entry */
  57         xfs_dir2_data_free_t    *dfp;           /* bestfree entry */
  58         xfs_dir2_data_unused_t  *dup;           /* unused entry */
  59         char                    *endp;          /* end of useful data */
  60         int                     freeseen;       /* mask of bestfrees seen */
  61         xfs_dahash_t            hash;           /* hash of current name */
  62         int                     i;              /* leaf index */
  63         int                     lastfree;       /* last entry was unused */
  64         xfs_dir2_leaf_entry_t   *lep=NULL;      /* block leaf entries */
  65         xfs_mount_t             *mp;            /* filesystem mount point */
  66         char                    *p;             /* current data position */
  67         int                     stale;          /* count of stale leaves */
  68         struct xfs_name         name;
  69
  70         mp = dp->i_mount;
  71         d = bp->data;
  72         ASSERT(be32_to_cpu(d->hdr.magic) == XFS_DIR2_DATA_MAGIC ||
  73                be32_to_cpu(d->hdr.magic) == XFS_DIR2_BLOCK_MAGIC);
  74         bf = d->hdr.bestfree;
  75         p = (char *)d->u;
  76         if (be32_to_cpu(d->hdr.magic) == XFS_DIR2_BLOCK_MAGIC) {
  77                 btp = xfs_dir2_block_tail_p(mp, (xfs_dir2_block_t *)d);
  78                 lep = xfs_dir2_block_leaf_p(btp);
  79                 endp = (char *)lep;
  80         } else
  81                 endp = (char *)d + mp->m_dirblksize;
  82         count = lastfree = freeseen = 0;
  83         /*
  84          * Account for zero bestfree entries.
  85          */
  86         if (!bf[0].length) {
  87                 ASSERT(!bf[0].offset);
  88                 freeseen |= 1 << 0;
  89         }
  90         if (!bf[1].length) {
  91                 ASSERT(!bf[1].offset);
  92                 freeseen |= 1 << 1;
  93         }
  94         if (!bf[2].length) {
  95                 ASSERT(!bf[2].offset);
  96                 freeseen |= 1 << 2;
  97         }
  98         ASSERT(be16_to_cpu(bf[0].length) >= be16_to_cpu(bf[1].length));
  99         ASSERT(be16_to_cpu(bf[1].length) >= be16_to_cpu(bf[2].length));
 100         /*
 101          * Loop over the data/unused entries.
 102          */
 103         while (p < endp) {
 104                 dup = (xfs_dir2_data_unused_t *)p;
 105                 /*
 106                  * If it's unused, look for the space in the bestfree table.
 107                  * If we find it, account for that, else make sure it
 108                  * doesn't need to be there.
 109                  */
 110                 if (be16_to_cpu(dup->freetag) == XFS_DIR2_DATA_FREE_TAG) {
 111                         ASSERT(lastfree == 0);
 112                         ASSERT(be16_to_cpu(*xfs_dir2_data_unused_tag_p(dup)) ==
 113                                (char *)dup - (char *)d);
 114                         dfp = xfs_dir2_data_freefind(d, dup);
 115                         if (dfp) {
 116                                 i = (int)(dfp - bf);
 117                                 ASSERT((freeseen & (1 << i)) == 0);
 118                                 freeseen |= 1 << i;
 119                         } else {
 120                                 ASSERT(be16_to_cpu(dup->length) <=
 121                                        be16_to_cpu(bf[2].length));
 122                         }
 123                         p += be16_to_cpu(dup->length);
 124                         lastfree = 1;
 125                         continue;
 126                 }
 127                 /*
 128                  * It's a real entry.  Validate the fields.
 129                  * If this is a block directory then make sure it's
 130                  * in the leaf section of the block.
 131                  * The linear search is crude but this is DEBUG code.
 132                  */
 133                 dep = (xfs_dir2_data_entry_t *)p;
 134                 ASSERT(dep->namelen != 0);
 135                 ASSERT(xfs_dir_ino_validate(mp, be64_to_cpu(dep->inumber)) == 0);
 136                 ASSERT(be16_to_cpu(*xfs_dir2_data_entry_tag_p(dep)) ==
 137                        (char *)dep - (char *)d);
 138                 count++;
 139                 lastfree = 0;
 140                 if (be32_to_cpu(d->hdr.magic) == XFS_DIR2_BLOCK_MAGIC) {
 141                         addr = xfs_dir2_db_off_to_dataptr(mp, mp->m_dirdatablk,
 142                                 (xfs_dir2_data_aoff_t)
 143                                 ((char *)dep - (char *)d));
 144                         name.name = dep->name;
 145                         name.len = dep->namelen;
 146                         hash = mp->m_dirnameops->hashname(&name);
 147                         for (i = 0; i < be32_to_cpu(btp->count); i++) {
 148                                 if (be32_to_cpu(lep[i].address) == addr &&
 149                                     be32_to_cpu(lep[i].hashval) == hash)
 150                                         break;
 151                         }
 152                         ASSERT(i < be32_to_cpu(btp->count));
 153                 }
 154                 p += xfs_dir2_data_entsize(dep->namelen);
 155         }
 156         /*
 157          * Need to have seen all the entries and all the bestfree slots.
 158          */
 159         ASSERT(freeseen == 7);
 160         if (be32_to_cpu(d->hdr.magic) == XFS_DIR2_BLOCK_MAGIC) {
 161                 for (i = stale = 0; i < be32_to_cpu(btp->count); i++) {
 162                         if (be32_to_cpu(lep[i].address) == XFS_DIR2_NULL_DATAPTR)
 163                                 stale++;
 164                         if (i > 0)
 165                                 ASSERT(be32_to_cpu(lep[i].hashval) >= be32_to_cpu(lep[i - 1].hashval));
 166                 }
 167                 ASSERT(count == be32_to_cpu(btp->count) - be32_to_cpu(btp->stale));
 168                 ASSERT(stale == be32_to_cpu(btp->stale));
 169         }
 170 }
 171 #endif
 172
 173 /*
 174  * Given a data block and an unused entry from that block,
 175  * return the bestfree entry if any that corresponds to it.
 176  */
 177 xfs_dir2_data_free_t *
 178 xfs_dir2_data_freefind(
 179         xfs_dir2_data_t         *d,             /* data block */
 180         xfs_dir2_data_unused_t  *dup)           /* data unused entry */
 181 {
 182         xfs_dir2_data_free_t    *dfp;           /* bestfree entry */
 183         xfs_dir2_data_aoff_t    off;            /* offset value needed */
 184 #if defined(DEBUG) && defined(__KERNEL__)
 185         int                     matched;        /* matched the value */
 186         int                     seenzero;       /* saw a 0 bestfree entry */
 187 #endif
 188
 189         off = (xfs_dir2_data_aoff_t)((char *)dup - (char *)d);
 190 #if defined(DEBUG) && defined(__KERNEL__)
 191         /*
 192          * Validate some consistency in the bestfree table.
 193          * Check order, non-overlapping entries, and if we find the
 194          * one we're looking for it has to be exact.
 195          */
 196         ASSERT(be32_to_cpu(d->hdr.magic) == XFS_DIR2_DATA_MAGIC ||
 197                be32_to_cpu(d->hdr.magic) == XFS_DIR2_BLOCK_MAGIC);
 198         for (dfp = &d->hdr.bestfree[0], seenzero = matched = 0;
 199              dfp < &d->hdr.bestfree[XFS_DIR2_DATA_FD_COUNT];
 200              dfp++) {
 201                 if (!dfp->offset) {
 202                         ASSERT(!dfp->length);
 203                         seenzero = 1;
 204                         continue;
 205                 }
 206                 ASSERT(seenzero == 0);
 207                 if (be16_to_cpu(dfp->offset) == off) {
 208                         matched = 1;
 209                         ASSERT(dfp->length == dup->length);
 210                 } else if (off < be16_to_cpu(dfp->offset))
 211                         ASSERT(off + be16_to_cpu(dup->length) <= be16_to_cpu(dfp->offset));
 212                 else
 213                         ASSERT(be16_to_cpu(dfp->offset) + be16_to_cpu(dfp->length) <= off);
 214                 ASSERT(matched || be16_to_cpu(dfp->length) >= be16_to_cpu(dup->length));
 215                 if (dfp > &d->hdr.bestfree[0])
 216                         ASSERT(be16_to_cpu(dfp[-1].length) >= be16_to_cpu(dfp[0].length));
 217         }
 218 #endif
 219         /*
 220          * If this is smaller than the smallest bestfree entry,
 221          * it can't be there since they're sorted.
 222          */
 223         if (be16_to_cpu(dup->length) <
 224             be16_to_cpu(d->hdr.bestfree[XFS_DIR2_DATA_FD_COUNT - 1].length))
 225                 return NULL;
 226         /*
 227          * Look at the three bestfree entries for our guy.
 228          */
 229         for (dfp = &d->hdr.bestfree[0];
 230              dfp < &d->hdr.bestfree[XFS_DIR2_DATA_FD_COUNT];
 231              dfp++) {
 232                 if (!dfp->offset)
 233                         return NULL;
 234                 if (be16_to_cpu(dfp->offset) == off)
 235                         return dfp;
 236         }
 237         /*
 238          * Didn't find it.  This only happens if there are duplicate lengths.
 239          */
 240         return NULL;
 241 }
 242
 243 /*
 244  * Insert an unused-space entry into the bestfree table.
 245  */
 246 xfs_dir2_data_free_t *                          /* entry inserted */
 247 xfs_dir2_data_freeinsert(
 248         xfs_dir2_data_t         *d,             /* data block pointer */
 249         xfs_dir2_data_unused_t  *dup,           /* unused space */
 250         int                     *loghead)       /* log the data header (out) */
 251 {
 252         xfs_dir2_data_free_t    *dfp;           /* bestfree table pointer */
 253         xfs_dir2_data_free_t    new;            /* new bestfree entry */
 254
 255 #ifdef __KERNEL__
 256         ASSERT(be32_to_cpu(d->hdr.magic) == XFS_DIR2_DATA_MAGIC ||
 257                be32_to_cpu(d->hdr.magic) == XFS_DIR2_BLOCK_MAGIC);
 258 #endif
 259         dfp = d->hdr.bestfree;
 260         new.length = dup->length;
 261         new.offset = cpu_to_be16((char *)dup - (char *)d);
 262         /*
 263          * Insert at position 0, 1, or 2; or not at all.
 264          */
 265         if (be16_to_cpu(new.length) > be16_to_cpu(dfp[0].length)) {
 266                 dfp[2] = dfp[1];
 267                 dfp[1] = dfp[0];
 268                 dfp[0] = new;
 269                 *loghead = 1;
 270                 return &dfp[0];
 271         }
 272         if (be16_to_cpu(new.length) > be16_to_cpu(dfp[1].length)) {
 273                 dfp[2] = dfp[1];
 274                 dfp[1] = new;
 275                 *loghead = 1;
 276                 return &dfp[1];
 277         }
 278         if (be16_to_cpu(new.length) > be16_to_cpu(dfp[2].length)) {
 279                 dfp[2] = new;
 280                 *loghead = 1;
 281                 return &dfp[2];
 282         }
 283         return NULL;
 284 }
 285
 286 /*
 287  * Remove a bestfree entry from the table.
 288  */
 289 STATIC void
 290 xfs_dir2_data_freeremove(
 291         xfs_dir2_data_t         *d,             /* data block pointer */
 292         xfs_dir2_data_free_t    *dfp,           /* bestfree entry pointer */
 293         int                     *loghead)       /* out: log data header */
 294 {
 295 #ifdef __KERNEL__
 296         ASSERT(be32_to_cpu(d->hdr.magic) == XFS_DIR2_DATA_MAGIC ||
 297                be32_to_cpu(d->hdr.magic) == XFS_DIR2_BLOCK_MAGIC);
 298 #endif
 299         /*
 300          * It's the first entry, slide the next 2 up.
 301          */
 302         if (dfp == &d->hdr.bestfree[0]) {
 303                 d->hdr.bestfree[0] = d->hdr.bestfree[1];
 304                 d->hdr.bestfree[1] = d->hdr.bestfree[2];
 305         }
 306         /*
 307          * It's the second entry, slide the 3rd entry up.
 308          */
 309         else if (dfp == &d->hdr.bestfree[1])
 310                 d->hdr.bestfree[1] = d->hdr.bestfree[2];
 311         /*
 312          * Must be the last entry.
 313          */
 314         else
 315                 ASSERT(dfp == &d->hdr.bestfree[2]);
 316         /*
 317          * Clear the 3rd entry, must be zero now.
 318          */
 319         d->hdr.bestfree[2].length = 0;
 320         d->hdr.bestfree[2].offset = 0;
 321         *loghead = 1;
 322 }
 323
 324 /*
 325  * Given a data block, reconstruct its bestfree map.
 326  */
 327 void
 328 xfs_dir2_data_freescan(
 329         xfs_mount_t             *mp,            /* filesystem mount point */
 330         xfs_dir2_data_t         *d,             /* data block pointer */
 331         int                     *loghead)       /* out: log data header */
 332 {
 333         xfs_dir2_block_tail_t   *btp;           /* block tail */
 334         xfs_dir2_data_entry_t   *dep;           /* active data entry */
 335         xfs_dir2_data_unused_t  *dup;           /* unused data entry */
 336         char                    *endp;          /* end of block's data */
 337         char                    *p;             /* current entry pointer */
 338
 339 #ifdef __KERNEL__
 340         ASSERT(be32_to_cpu(d->hdr.magic) == XFS_DIR2_DATA_MAGIC ||
 341                be32_to_cpu(d->hdr.magic) == XFS_DIR2_BLOCK_MAGIC);
 342 #endif
 343         /*
 344          * Start by clearing the table.
 345          */
 346         memset(d->hdr.bestfree, 0, sizeof(d->hdr.bestfree));
 347         *loghead = 1;
 348         /*
 349          * Set up pointers.
 350          */
 351         p = (char *)d->u;
 352         if (be32_to_cpu(d->hdr.magic) == XFS_DIR2_BLOCK_MAGIC) {
 353                 btp = xfs_dir2_block_tail_p(mp, (xfs_dir2_block_t *)d);
 354                 endp = (char *)xfs_dir2_block_leaf_p(btp);
 355         } else
 356                 endp = (char *)d + mp->m_dirblksize;
 357         /*
 358          * Loop over the block's entries.
 359          */
 360         while (p < endp) {
 361                 dup = (xfs_dir2_data_unused_t *)p;
 362                 /*
 363                  * If it's a free entry, insert it.
 364                  */
 365                 if (be16_to_cpu(dup->freetag) == XFS_DIR2_DATA_FREE_TAG) {
 366                         ASSERT((char *)dup - (char *)d ==
 367                                be16_to_cpu(*xfs_dir2_data_unused_tag_p(dup)));
 368                         xfs_dir2_data_freeinsert(d, dup, loghead);
 369                         p += be16_to_cpu(dup->length);
 370                 }
 371                 /*
 372                  * For active entries, check their tags and skip them.
 373                  */
 374                 else {
 375                         dep = (xfs_dir2_data_entry_t *)p;
 376                         ASSERT((char *)dep - (char *)d ==
 377                                be16_to_cpu(*xfs_dir2_data_entry_tag_p(dep)));
 378                         p += xfs_dir2_data_entsize(dep->namelen);
 379                 }
 380         }
 381 }
 382
 383 /*
 384  * Initialize a data block at the given block number in the directory.
 385  * Give back the buffer for the created block.
 386  */
 387 int                                             /* error */
 388 xfs_dir2_data_init(
 389         xfs_da_args_t           *args,          /* directory operation args */
 390         xfs_dir2_db_t           blkno,          /* logical dir block number */
 391         xfs_dabuf_t             **bpp)          /* output block buffer */
 392 {
 393         xfs_dabuf_t             *bp;            /* block buffer */
 394         xfs_dir2_data_t         *d;             /* pointer to block */
 395         xfs_inode_t             *dp;            /* incore directory inode */
 396         xfs_dir2_data_unused_t  *dup;           /* unused entry pointer */
 397         int                     error;          /* error return value */
 398         int                     i;              /* bestfree index */
 399         xfs_mount_t             *mp;            /* filesystem mount point */
 400         xfs_trans_t             *tp;            /* transaction pointer */
 401         int                     t;              /* temp */
 402
 403         dp = args->dp;
 404         mp = dp->i_mount;
 405         tp = args->trans;
 406         /*
 407          * Get the buffer set up for the block.
 408          */
 409         error = xfs_da_get_buf(tp, dp, xfs_dir2_db_to_da(mp, blkno), -1, &bp,
 410                 XFS_DATA_FORK);
 411         if (error) {
 412                 return error;
 413         }
 414         ASSERT(bp != NULL);
 415         /*
 416          * Initialize the header.
 417          */
 418         d = bp->data;
 419         d->hdr.magic = cpu_to_be32(XFS_DIR2_DATA_MAGIC);
 420         d->hdr.bestfree[0].offset = cpu_to_be16(sizeof(d->hdr));
 421         for (i = 1; i < XFS_DIR2_DATA_FD_COUNT; i++) {
 422                 d->hdr.bestfree[i].length = 0;
 423                 d->hdr.bestfree[i].offset = 0;
 424         }
 425         /*
 426          * Set up an unused entry for the block's body.
 427          */
 428         dup = &d->u[0].unused;
 429         dup->freetag = cpu_to_be16(XFS_DIR2_DATA_FREE_TAG);
 430
 431         t=mp->m_dirblksize - (uint)sizeof(d->hdr);
 432         d->hdr.bestfree[0].length = cpu_to_be16(t);
 433         dup->length = cpu_to_be16(t);
 434         *xfs_dir2_data_unused_tag_p(dup) = cpu_to_be16((char *)dup - (char *)d);
 435         /*
 436          * Log it and return it.
 437          */
 438         xfs_dir2_data_log_header(tp, bp);
 439         xfs_dir2_data_log_unused(tp, bp, dup);
 440         *bpp = bp;
 441         return 0;
 442 }
 443
 444 /*
 445  * Log an active data entry from the block.
 446  */
 447 void
 448 xfs_dir2_data_log_entry(
 449         xfs_trans_t             *tp,            /* transaction pointer */
 450         xfs_dabuf_t             *bp,            /* block buffer */
 451         xfs_dir2_data_entry_t   *dep)           /* data entry pointer */
 452 {
 453         xfs_dir2_data_t         *d;             /* data block pointer */
 454
 455         d = bp->data;
 456         ASSERT(be32_to_cpu(d->hdr.magic) == XFS_DIR2_DATA_MAGIC ||
 457                be32_to_cpu(d->hdr.magic) == XFS_DIR2_BLOCK_MAGIC);
 458         xfs_da_log_buf(tp, bp, (uint)((char *)dep - (char *)d),
 459                 (uint)((char *)(xfs_dir2_data_entry_tag_p(dep) + 1) -
 460                        (char *)d - 1));
 461 }
 462
 463 /*
 464  * Log a data block header.
 465  */
 466 void
 467 xfs_dir2_data_log_header(
 468         xfs_trans_t             *tp,            /* transaction pointer */
 469         xfs_dabuf_t             *bp)            /* block buffer */
 470 {
 471         xfs_dir2_data_t         *d;             /* data block pointer */
 472
 473         d = bp->data;
 474         ASSERT(be32_to_cpu(d->hdr.magic) == XFS_DIR2_DATA_MAGIC ||
 475                be32_to_cpu(d->hdr.magic) == XFS_DIR2_BLOCK_MAGIC);
 476         xfs_da_log_buf(tp, bp, (uint)((char *)&d->hdr - (char *)d),
 477                 (uint)(sizeof(d->hdr) - 1));
 478 }
 479
 480 /*
 481  * Log a data unused entry.
 482  */
 483 void
 484 xfs_dir2_data_log_unused(
 485         xfs_trans_t             *tp,            /* transaction pointer */
 486         xfs_dabuf_t             *bp,            /* block buffer */
 487         xfs_dir2_data_unused_t  *dup)           /* data unused pointer */
 488 {
 489         xfs_dir2_data_t         *d;             /* data block pointer */
 490
 491         d = bp->data;
 492         ASSERT(be32_to_cpu(d->hdr.magic) == XFS_DIR2_DATA_MAGIC ||
 493                be32_to_cpu(d->hdr.magic) == XFS_DIR2_BLOCK_MAGIC);
 494         /*
 495          * Log the first part of the unused entry.
 496          */
 497         xfs_da_log_buf(tp, bp, (uint)((char *)dup - (char *)d),
 498                 (uint)((char *)&dup->length + sizeof(dup->length) -
 499                        1 - (char *)d));
 500         /*
 501          * Log the end (tag) of the unused entry.
 502          */
 503         xfs_da_log_buf(tp, bp,
 504                 (uint)((char *)xfs_dir2_data_unused_tag_p(dup) - (char *)d),
 505                 (uint)((char *)xfs_dir2_data_unused_tag_p(dup) - (char *)d +
 506                        sizeof(xfs_dir2_data_off_t) - 1));
 507 }
 508
 509 /*
 510  * Make a byte range in the data block unused.
 511  * Its current contents are unimportant.
 512  */
 513 void
 514 xfs_dir2_data_make_free(
 515         xfs_trans_t             *tp,            /* transaction pointer */
 516         xfs_dabuf_t             *bp,            /* block buffer */
 517         xfs_dir2_data_aoff_t    offset,         /* starting byte offset */
 518         xfs_dir2_data_aoff_t    len,            /* length in bytes */
 519         int                     *needlogp,      /* out: log header */
 520         int                     *needscanp)     /* out: regen bestfree */
 521 {
 522         xfs_dir2_data_t         *d;             /* data block pointer */
 523         xfs_dir2_data_free_t    *dfp;           /* bestfree pointer */
 524         char                    *endptr;        /* end of data area */
 525         xfs_mount_t             *mp;            /* filesystem mount point */
 526         int                     needscan;       /* need to regen bestfree */
 527         xfs_dir2_data_unused_t  *newdup;        /* new unused entry */
 528         xfs_dir2_data_unused_t  *postdup;       /* unused entry after us */
 529         xfs_dir2_data_unused_t  *prevdup;       /* unused entry before us */
 530
 531         mp = tp->t_mountp;
 532         d = bp->data;
 533         /*
 534          * Figure out where the end of the data area is.
 535          */
 536         if (be32_to_cpu(d->hdr.magic) == XFS_DIR2_DATA_MAGIC)
 537                 endptr = (char *)d + mp->m_dirblksize;
 538         else {
 539                 xfs_dir2_block_tail_t   *btp;   /* block tail */
 540
 541                 ASSERT(be32_to_cpu(d->hdr.magic) == XFS_DIR2_BLOCK_MAGIC);
 542                 btp = xfs_dir2_block_tail_p(mp, (xfs_dir2_block_t *)d);
 543                 endptr = (char *)xfs_dir2_block_leaf_p(btp);
 544         }
 545         /*
 546          * If this isn't the start of the block, then back up to
 547          * the previous entry and see if it's free.
 548          */
 549         if (offset > sizeof(d->hdr)) {
 550                 __be16                  *tagp;  /* tag just before us */
 551
 552                 tagp = (__be16 *)((char *)d + offset) - 1;
 553                 prevdup = (xfs_dir2_data_unused_t *)((char *)d + be16_to_cpu(*tagp));
 554                 if (be16_to_cpu(prevdup->freetag) != XFS_DIR2_DATA_FREE_TAG)
 555                         prevdup = NULL;
 556         } else
 557                 prevdup = NULL;
 558         /*
 559          * If this isn't the end of the block, see if the entry after
 560          * us is free.
 561          */
 562         if ((char *)d + offset + len < endptr) {
 563                 postdup =
 564                         (xfs_dir2_data_unused_t *)((char *)d + offset + len);
 565                 if (be16_to_cpu(postdup->freetag) != XFS_DIR2_DATA_FREE_TAG)
 566                         postdup = NULL;
 567         } else
 568                 postdup = NULL;
 569         ASSERT(*needscanp == 0);
 570         needscan = 0;
 571         /*
 572          * Previous and following entries are both free,
 573          * merge everything into a single free entry.
 574          */
 575         if (prevdup && postdup) {
 576                 xfs_dir2_data_free_t    *dfp2;  /* another bestfree pointer */
 577
 578                 /*
 579                  * See if prevdup and/or postdup are in bestfree table.
 580                  */
 581                 dfp = xfs_dir2_data_freefind(d, prevdup);
 582                 dfp2 = xfs_dir2_data_freefind(d, postdup);
 583                 /*
 584                  * We need a rescan unless there are exactly 2 free entries
 585                  * namely our two.  Then we know what's happening, otherwise
 586                  * since the third bestfree is there, there might be more
 587                  * entries.
 588                  */
 589                 needscan = (d->hdr.bestfree[2].length != 0);
 590                 /*
 591                  * Fix up the new big freespace.
 592                  */
 593                 be16_add_cpu(&prevdup->length, len + be16_to_cpu(postdup->length));
 594                 *xfs_dir2_data_unused_tag_p(prevdup) =
 595                         cpu_to_be16((char *)prevdup - (char *)d);
 596                 xfs_dir2_data_log_unused(tp, bp, prevdup);
 597                 if (!needscan) {
 598                         /*
 599                          * Has to be the case that entries 0 and 1 are
 600                          * dfp and dfp2 (don't know which is which), and
 601                          * entry 2 is empty.
 602                          * Remove entry 1 first then entry 0.
 603                          */
 604                         ASSERT(dfp && dfp2);
 605                         if (dfp == &d->hdr.bestfree[1]) {
 606                                 dfp = &d->hdr.bestfree[0];
 607                                 ASSERT(dfp2 == dfp);
 608                                 dfp2 = &d->hdr.bestfree[1];
 609                         }
 610                         xfs_dir2_data_freeremove(d, dfp2, needlogp);
 611                         xfs_dir2_data_freeremove(d, dfp, needlogp);
 612                         /*
 613                          * Now insert the new entry.
 614                          */
 615                         dfp = xfs_dir2_data_freeinsert(d, prevdup, needlogp);
 616                         ASSERT(dfp == &d->hdr.bestfree[0]);
 617                         ASSERT(dfp->length == prevdup->length);
 618                         ASSERT(!dfp[1].length);
 619                         ASSERT(!dfp[2].length);
 620                 }
 621         }
 622         /*
 623          * The entry before us is free, merge with it.
 624          */
 625         else if (prevdup) {
 626                 dfp = xfs_dir2_data_freefind(d, prevdup);
 627                 be16_add_cpu(&prevdup->length, len);
 628                 *xfs_dir2_data_unused_tag_p(prevdup) =
 629                         cpu_to_be16((char *)prevdup - (char *)d);
 630                 xfs_dir2_data_log_unused(tp, bp, prevdup);
 631                 /*
 632                  * If the previous entry was in the table, the new entry
 633                  * is longer, so it will be in the table too.  Remove
 634                  * the old one and add the new one.
 635                  */
 636                 if (dfp) {
 637                         xfs_dir2_data_freeremove(d, dfp, needlogp);
 638                         (void)xfs_dir2_data_freeinsert(d, prevdup, needlogp);
 639                 }
 640                 /*
 641                  * Otherwise we need a scan if the new entry is big enough.
 642                  */
 643                 else {
 644                         needscan = be16_to_cpu(prevdup->length) >
 645                                    be16_to_cpu(d->hdr.bestfree[2].length);
 646                 }
 647         }
 648         /*
 649          * The following entry is free, merge with it.
 650          */
 651         else if (postdup) {
 652                 dfp = xfs_dir2_data_freefind(d, postdup);
 653                 newdup = (xfs_dir2_data_unused_t *)((char *)d + offset);
 654                 newdup->freetag = cpu_to_be16(XFS_DIR2_DATA_FREE_TAG);
 655                 newdup->length = cpu_to_be16(len + be16_to_cpu(postdup->length));
 656                 *xfs_dir2_data_unused_tag_p(newdup) =
 657                         cpu_to_be16((char *)newdup - (char *)d);
 658                 xfs_dir2_data_log_unused(tp, bp, newdup);
 659                 /*
 660                  * If the following entry was in the table, the new entry
 661                  * is longer, so it will be in the table too.  Remove
 662                  * the old one and add the new one.
 663                  */
 664                 if (dfp) {
 665                         xfs_dir2_data_freeremove(d, dfp, needlogp);
 666                         (void)xfs_dir2_data_freeinsert(d, newdup, needlogp);
 667                 }
 668                 /*
 669                  * Otherwise we need a scan if the new entry is big enough.
 670                  */
 671                 else {
 672                         needscan = be16_to_cpu(newdup->length) >
 673                                    be16_to_cpu(d->hdr.bestfree[2].length);
 674                 }
 675         }
 676         /*
 677          * Neither neighbor is free.  Make a new entry.
 678          */
 679         else {
 680                 newdup = (xfs_dir2_data_unused_t *)((char *)d + offset);
 681                 newdup->freetag = cpu_to_be16(XFS_DIR2_DATA_FREE_TAG);
 682                 newdup->length = cpu_to_be16(len);
 683                 *xfs_dir2_data_unused_tag_p(newdup) =
 684                         cpu_to_be16((char *)newdup - (char *)d);
 685                 xfs_dir2_data_log_unused(tp, bp, newdup);
 686                 (void)xfs_dir2_data_freeinsert(d, newdup, needlogp);
 687         }
 688         *needscanp = needscan;
 689 }
 690
 691 /*
 692  * Take a byte range out of an existing unused space and make it un-free.
 693  */
 694 void
 695 xfs_dir2_data_use_free(
 696         xfs_trans_t             *tp,            /* transaction pointer */
 697         xfs_dabuf_t             *bp,            /* data block buffer */
 698         xfs_dir2_data_unused_t  *dup,           /* unused entry */
 699         xfs_dir2_data_aoff_t    offset,         /* starting offset to use */
 700         xfs_dir2_data_aoff_t    len,            /* length to use */
 701         int                     *needlogp,      /* out: need to log header */
 702         int                     *needscanp)     /* out: need regen bestfree */
 703 {
 704         xfs_dir2_data_t         *d;             /* data block */
 705         xfs_dir2_data_free_t    *dfp;           /* bestfree pointer */
 706         int                     matchback;      /* matches end of freespace */
 707         int                     matchfront;     /* matches start of freespace */
 708         int                     needscan;       /* need to regen bestfree */
 709         xfs_dir2_data_unused_t  *newdup;        /* new unused entry */
 710         xfs_dir2_data_unused_t  *newdup2;       /* another new unused entry */
 711         int                     oldlen;         /* old unused entry's length */
 712
 713         d = bp->data;
 714         ASSERT(be32_to_cpu(d->hdr.magic) == XFS_DIR2_DATA_MAGIC ||
 715                be32_to_cpu(d->hdr.magic) == XFS_DIR2_BLOCK_MAGIC);
 716         ASSERT(be16_to_cpu(dup->freetag) == XFS_DIR2_DATA_FREE_TAG);
 717         ASSERT(offset >= (char *)dup - (char *)d);
 718         ASSERT(offset + len <= (char *)dup + be16_to_cpu(dup->length) - (char *)d);
 719         ASSERT((char *)dup - (char *)d == be16_to_cpu(*xfs_dir2_data_unused_tag_p(dup)));
 720         /*
 721          * Look up the entry in the bestfree table.
 722          */
 723         dfp = xfs_dir2_data_freefind(d, dup);
 724         oldlen = be16_to_cpu(dup->length);
 725         ASSERT(dfp || oldlen <= be16_to_cpu(d->hdr.bestfree[2].length));
 726         /*
 727          * Check for alignment with front and back of the entry.
 728          */
 729         matchfront = (char *)dup - (char *)d == offset;
 730         matchback = (char *)dup + oldlen - (char *)d == offset + len;
 731         ASSERT(*needscanp == 0);
 732         needscan = 0;
 733         /*
 734          * If we matched it exactly we just need to get rid of it from
 735          * the bestfree table.
 736          */
 737         if (matchfront && matchback) {
 738                 if (dfp) {
 739                         needscan = (d->hdr.bestfree[2].offset != 0);
 740                         if (!needscan)
 741                                 xfs_dir2_data_freeremove(d, dfp, needlogp);
 742                 }
 743         }
 744         /*
 745          * We match the first part of the entry.
 746          * Make a new entry with the remaining freespace.
 747          */
 748         else if (matchfront) {
 749                 newdup = (xfs_dir2_data_unused_t *)((char *)d + offset + len);
 750                 newdup->freetag = cpu_to_be16(XFS_DIR2_DATA_FREE_TAG);
 751                 newdup->length = cpu_to_be16(oldlen - len);
 752                 *xfs_dir2_data_unused_tag_p(newdup) =
 753                         cpu_to_be16((char *)newdup - (char *)d);
 754                 xfs_dir2_data_log_unused(tp, bp, newdup);
 755                 /*
 756                  * If it was in the table, remove it and add the new one.
 757                  */
 758                 if (dfp) {
 759                         xfs_dir2_data_freeremove(d, dfp, needlogp);
 760                         dfp = xfs_dir2_data_freeinsert(d, newdup, needlogp);
 761                         ASSERT(dfp != NULL);
 762                         ASSERT(dfp->length == newdup->length);
 763                         ASSERT(be16_to_cpu(dfp->offset) == (char *)newdup - (char *)d);
 764                         /*
 765                          * If we got inserted at the last slot,
 766                          * that means we don't know if there was a better
 767                          * choice for the last slot, or not.  Rescan.
 768                          */
 769                         needscan = dfp == &d->hdr.bestfree[2];
 770                 }
 771         }
 772         /*
 773          * We match the last part of the entry.
 774          * Trim the allocated space off the tail of the entry.
 775          */
 776         else if (matchback) {
 777                 newdup = dup;
 778                 newdup->length = cpu_to_be16(((char *)d + offset) - (char *)newdup);
 779                 *xfs_dir2_data_unused_tag_p(newdup) =
 780                         cpu_to_be16((char *)newdup - (char *)d);
 781                 xfs_dir2_data_log_unused(tp, bp, newdup);
 782                 /*
 783                  * If it was in the table, remove it and add the new one.
 784                  */
 785                 if (dfp) {
 786                         xfs_dir2_data_freeremove(d, dfp, needlogp);
 787                         dfp = xfs_dir2_data_freeinsert(d, newdup, needlogp);
 788                         ASSERT(dfp != NULL);
 789                         ASSERT(dfp->length == newdup->length);
 790                         ASSERT(be16_to_cpu(dfp->offset) == (char *)newdup - (char *)d);
 791                         /*
 792                          * If we got inserted at the last slot,
 793                          * that means we don't know if there was a better
 794                          * choice for the last slot, or not.  Rescan.
 795                          */
 796                         needscan = dfp == &d->hdr.bestfree[2];
 797                 }
 798         }
 799         /*
 800          * Poking out the middle of an entry.
 801          * Make two new entries.
 802          */
 803         else {
 804                 newdup = dup;
 805                 newdup->length = cpu_to_be16(((char *)d + offset) - (char *)newdup);
 806                 *xfs_dir2_data_unused_tag_p(newdup) =
 807                         cpu_to_be16((char *)newdup - (char *)d);
 808                 xfs_dir2_data_log_unused(tp, bp, newdup);
 809                 newdup2 = (xfs_dir2_data_unused_t *)((char *)d + offset + len);
 810                 newdup2->freetag = cpu_to_be16(XFS_DIR2_DATA_FREE_TAG);
 811                 newdup2->length = cpu_to_be16(oldlen - len - be16_to_cpu(newdup->length));
 812                 *xfs_dir2_data_unused_tag_p(newdup2) =
 813                         cpu_to_be16((char *)newdup2 - (char *)d);
 814                 xfs_dir2_data_log_unused(tp, bp, newdup2);
 815                 /*
 816                  * If the old entry was in the table, we need to scan
 817                  * if the 3rd entry was valid, since these entries
 818                  * are smaller than the old one.
 819                  * If we don't need to scan that means there were 1 or 2
 820                  * entries in the table, and removing the old and adding
 821                  * the 2 new will work.
 822                  */
 823                 if (dfp) {
 824                         needscan = (d->hdr.bestfree[2].length != 0);
 825                         if (!needscan) {
 826                                 xfs_dir2_data_freeremove(d, dfp, needlogp);
 827                                 (void)xfs_dir2_data_freeinsert(d, newdup,
 828                                         needlogp);
 829                                 (void)xfs_dir2_data_freeinsert(d, newdup2,
 830                                         needlogp);
 831                         }
 832                 }
 833         }
 834         *needscanp = needscan;
 835 }