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