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_mount.h"
  27 #include "xfs_da_btree.h"
  28 #include "xfs_bmap_btree.h"
  29 #include "xfs_dinode.h"
  30 #include "xfs_inode.h"
  31 #include "xfs_dir2_format.h"
  32 #include "xfs_dir2_priv.h"
  33 #include "xfs_error.h"
  34
  35 STATIC xfs_dir2_data_free_t *
  36 xfs_dir2_data_freefind(xfs_dir2_data_hdr_t *hdr, xfs_dir2_data_unused_t *dup);
  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_hdr_t     *hdr;           /* data block header */
  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         hdr = bp->data;
  70         bf = hdr->bestfree;
  71         p = (char *)(hdr + 1);
  72
  73         if (hdr->magic == cpu_to_be32(XFS_DIR2_BLOCK_MAGIC)) {
  74                 btp = xfs_dir2_block_tail_p(mp, hdr);
  75                 lep = xfs_dir2_block_leaf_p(btp);
  76                 endp = (char *)lep;
  77         } else {
  78                 ASSERT(hdr->magic == cpu_to_be32(XFS_DIR2_DATA_MAGIC));
  79                 endp = (char *)hdr + mp->m_dirblksize;
  80         }
  81
  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 *)hdr);
 114                         dfp = xfs_dir2_data_freefind(hdr, 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 *)hdr);
 138                 count++;
 139                 lastfree = 0;
 140                 if (hdr->magic == cpu_to_be32(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 *)hdr));
 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 (hdr->magic == cpu_to_be32(XFS_DIR2_BLOCK_MAGIC)) {
 161                 for (i = stale = 0; i < be32_to_cpu(btp->count); i++) {
 162                         if (lep[i].address ==
 163                             cpu_to_be32(XFS_DIR2_NULL_DATAPTR))
 164                                 stale++;
 165                         if (i > 0)
 166                                 ASSERT(be32_to_cpu(lep[i].hashval) >= be32_to_cpu(lep[i - 1].hashval));
 167                 }
 168                 ASSERT(count == be32_to_cpu(btp->count) - be32_to_cpu(btp->stale));
 169                 ASSERT(stale == be32_to_cpu(btp->stale));
 170         }
 171 }
 172 #endif
 173
 174 /*
 175  * Given a data block and an unused entry from that block,
 176  * return the bestfree entry if any that corresponds to it.
 177  */
 178 STATIC xfs_dir2_data_free_t *
 179 xfs_dir2_data_freefind(
 180         xfs_dir2_data_hdr_t     *hdr,           /* data block */
 181         xfs_dir2_data_unused_t  *dup)           /* data unused entry */
 182 {
 183         xfs_dir2_data_free_t    *dfp;           /* bestfree entry */
 184         xfs_dir2_data_aoff_t    off;            /* offset value needed */
 185 #if defined(DEBUG) && defined(__KERNEL__)
 186         int                     matched;        /* matched the value */
 187         int                     seenzero;       /* saw a 0 bestfree entry */
 188 #endif
 189
 190         off = (xfs_dir2_data_aoff_t)((char *)dup - (char *)hdr);
 191 #if defined(DEBUG) && defined(__KERNEL__)
 192         /*
 193          * Validate some consistency in the bestfree table.
 194          * Check order, non-overlapping entries, and if we find the
 195          * one we're looking for it has to be exact.
 196          */
 197         ASSERT(hdr->magic == cpu_to_be32(XFS_DIR2_DATA_MAGIC) ||
 198                hdr->magic == cpu_to_be32(XFS_DIR2_BLOCK_MAGIC));
 199         for (dfp = &hdr->bestfree[0], seenzero = matched = 0;
 200              dfp < &hdr->bestfree[XFS_DIR2_DATA_FD_COUNT];
 201              dfp++) {
 202                 if (!dfp->offset) {
 203                         ASSERT(!dfp->length);
 204                         seenzero = 1;
 205                         continue;
 206                 }
 207                 ASSERT(seenzero == 0);
 208                 if (be16_to_cpu(dfp->offset) == off) {
 209                         matched = 1;
 210                         ASSERT(dfp->length == dup->length);
 211                 } else if (off < be16_to_cpu(dfp->offset))
 212                         ASSERT(off + be16_to_cpu(dup->length) <= be16_to_cpu(dfp->offset));
 213                 else
 214                         ASSERT(be16_to_cpu(dfp->offset) + be16_to_cpu(dfp->length) <= off);
 215                 ASSERT(matched || be16_to_cpu(dfp->length) >= be16_to_cpu(dup->length));
 216                 if (dfp > &hdr->bestfree[0])
 217                         ASSERT(be16_to_cpu(dfp[-1].length) >= be16_to_cpu(dfp[0].length));
 218         }
 219 #endif
 220         /*
 221          * If this is smaller than the smallest bestfree entry,
 222          * it can't be there since they're sorted.
 223          */
 224         if (be16_to_cpu(dup->length) <
 225             be16_to_cpu(hdr->bestfree[XFS_DIR2_DATA_FD_COUNT - 1].length))
 226                 return NULL;
 227         /*
 228          * Look at the three bestfree entries for our guy.
 229          */
 230         for (dfp = &hdr->bestfree[0];
 231              dfp < &hdr->bestfree[XFS_DIR2_DATA_FD_COUNT];
 232              dfp++) {
 233                 if (!dfp->offset)
 234                         return NULL;
 235                 if (be16_to_cpu(dfp->offset) == off)
 236                         return dfp;
 237         }
 238         /*
 239          * Didn't find it.  This only happens if there are duplicate lengths.
 240          */
 241         return NULL;
 242 }
 243
 244 /*
 245  * Insert an unused-space entry into the bestfree table.
 246  */
 247 xfs_dir2_data_free_t *                          /* entry inserted */
 248 xfs_dir2_data_freeinsert(
 249         xfs_dir2_data_hdr_t     *hdr,           /* data block pointer */
 250         xfs_dir2_data_unused_t  *dup,           /* unused space */
 251         int                     *loghead)       /* log the data header (out) */
 252 {
 253         xfs_dir2_data_free_t    *dfp;           /* bestfree table pointer */
 254         xfs_dir2_data_free_t    new;            /* new bestfree entry */
 255
 256 #ifdef __KERNEL__
 257         ASSERT(hdr->magic == cpu_to_be32(XFS_DIR2_DATA_MAGIC) ||
 258                hdr->magic == cpu_to_be32(XFS_DIR2_BLOCK_MAGIC));
 259 #endif
 260         dfp = hdr->bestfree;
 261         new.length = dup->length;
 262         new.offset = cpu_to_be16((char *)dup - (char *)hdr);
 263
 264         /*
 265          * Insert at position 0, 1, or 2; or not at all.
 266          */
 267         if (be16_to_cpu(new.length) > be16_to_cpu(dfp[0].length)) {
 268                 dfp[2] = dfp[1];
 269                 dfp[1] = dfp[0];
 270                 dfp[0] = new;
 271                 *loghead = 1;
 272                 return &dfp[0];
 273         }
 274         if (be16_to_cpu(new.length) > be16_to_cpu(dfp[1].length)) {
 275                 dfp[2] = dfp[1];
 276                 dfp[1] = new;
 277                 *loghead = 1;
 278                 return &dfp[1];
 279         }
 280         if (be16_to_cpu(new.length) > be16_to_cpu(dfp[2].length)) {
 281                 dfp[2] = new;
 282                 *loghead = 1;
 283                 return &dfp[2];
 284         }
 285         return NULL;
 286 }
 287
 288 /*
 289  * Remove a bestfree entry from the table.
 290  */
 291 STATIC void
 292 xfs_dir2_data_freeremove(
 293         xfs_dir2_data_hdr_t     *hdr,           /* data block header */
 294         xfs_dir2_data_free_t    *dfp,           /* bestfree entry pointer */
 295         int                     *loghead)       /* out: log data header */
 296 {
 297 #ifdef __KERNEL__
 298         ASSERT(hdr->magic == cpu_to_be32(XFS_DIR2_DATA_MAGIC) ||
 299                hdr->magic == cpu_to_be32(XFS_DIR2_BLOCK_MAGIC));
 300 #endif
 301         /*
 302          * It's the first entry, slide the next 2 up.
 303          */
 304         if (dfp == &hdr->bestfree[0]) {
 305                 hdr->bestfree[0] = hdr->bestfree[1];
 306                 hdr->bestfree[1] = hdr->bestfree[2];
 307         }
 308         /*
 309          * It's the second entry, slide the 3rd entry up.
 310          */
 311         else if (dfp == &hdr->bestfree[1])
 312                 hdr->bestfree[1] = hdr->bestfree[2];
 313         /*
 314          * Must be the last entry.
 315          */
 316         else
 317                 ASSERT(dfp == &hdr->bestfree[2]);
 318         /*
 319          * Clear the 3rd entry, must be zero now.
 320          */
 321         hdr->bestfree[2].length = 0;
 322         hdr->bestfree[2].offset = 0;
 323         *loghead = 1;
 324 }
 325
 326 /*
 327  * Given a data block, reconstruct its bestfree map.
 328  */
 329 void
 330 xfs_dir2_data_freescan(
 331         xfs_mount_t             *mp,            /* filesystem mount point */
 332         xfs_dir2_data_hdr_t     *hdr,           /* data block header */
 333         int                     *loghead)       /* out: log data header */
 334 {
 335         xfs_dir2_block_tail_t   *btp;           /* block tail */
 336         xfs_dir2_data_entry_t   *dep;           /* active data entry */
 337         xfs_dir2_data_unused_t  *dup;           /* unused data entry */
 338         char                    *endp;          /* end of block's data */
 339         char                    *p;             /* current entry pointer */
 340
 341 #ifdef __KERNEL__
 342         ASSERT(hdr->magic == cpu_to_be32(XFS_DIR2_DATA_MAGIC) ||
 343                hdr->magic == cpu_to_be32(XFS_DIR2_BLOCK_MAGIC));
 344 #endif
 345         /*
 346          * Start by clearing the table.
 347          */
 348         memset(hdr->bestfree, 0, sizeof(hdr->bestfree));
 349         *loghead = 1;
 350         /*
 351          * Set up pointers.
 352          */
 353         p = (char *)(hdr + 1);
 354         if (hdr->magic == cpu_to_be32(XFS_DIR2_BLOCK_MAGIC)) {
 355                 btp = xfs_dir2_block_tail_p(mp, hdr);
 356                 endp = (char *)xfs_dir2_block_leaf_p(btp);
 357         } else
 358                 endp = (char *)hdr + mp->m_dirblksize;
 359         /*
 360          * Loop over the block's entries.
 361          */
 362         while (p < endp) {
 363                 dup = (xfs_dir2_data_unused_t *)p;
 364                 /*
 365                  * If it's a free entry, insert it.
 366                  */
 367                 if (be16_to_cpu(dup->freetag) == XFS_DIR2_DATA_FREE_TAG) {
 368                         ASSERT((char *)dup - (char *)hdr ==
 369                                be16_to_cpu(*xfs_dir2_data_unused_tag_p(dup)));
 370                         xfs_dir2_data_freeinsert(hdr, dup, loghead);
 371                         p += be16_to_cpu(dup->length);
 372                 }
 373                 /*
 374                  * For active entries, check their tags and skip them.
 375                  */
 376                 else {
 377                         dep = (xfs_dir2_data_entry_t *)p;
 378                         ASSERT((char *)dep - (char *)hdr ==
 379                                be16_to_cpu(*xfs_dir2_data_entry_tag_p(dep)));
 380                         p += xfs_dir2_data_entsize(dep->namelen);
 381                 }
 382         }
 383 }
 384
 385 /*
 386  * Initialize a data block at the given block number in the directory.
 387  * Give back the buffer for the created block.
 388  */
 389 int                                             /* error */
 390 xfs_dir2_data_init(
 391         xfs_da_args_t           *args,          /* directory operation args */
 392         xfs_dir2_db_t           blkno,          /* logical dir block number */
 393         xfs_dabuf_t             **bpp)          /* output block buffer */
 394 {
 395         xfs_dabuf_t             *bp;            /* block buffer */
 396         xfs_dir2_data_hdr_t     *hdr;           /* data block header */
 397         xfs_inode_t             *dp;            /* incore directory inode */
 398         xfs_dir2_data_unused_t  *dup;           /* unused entry pointer */
 399         int                     error;          /* error return value */
 400         int                     i;              /* bestfree index */
 401         xfs_mount_t             *mp;            /* filesystem mount point */
 402         xfs_trans_t             *tp;            /* transaction pointer */
 403         int                     t;              /* temp */
 404
 405         dp = args->dp;
 406         mp = dp->i_mount;
 407         tp = args->trans;
 408         /*
 409          * Get the buffer set up for the block.
 410          */
 411         error = xfs_da_get_buf(tp, dp, xfs_dir2_db_to_da(mp, blkno), -1, &bp,
 412                 XFS_DATA_FORK);
 413         if (error) {
 414                 return error;
 415         }
 416         ASSERT(bp != NULL);
 417
 418         /*
 419          * Initialize the header.
 420          */
 421         hdr = bp->data;
 422         hdr->magic = cpu_to_be32(XFS_DIR2_DATA_MAGIC);
 423         hdr->bestfree[0].offset = cpu_to_be16(sizeof(*hdr));
 424         for (i = 1; i < XFS_DIR2_DATA_FD_COUNT; i++) {
 425                 hdr->bestfree[i].length = 0;
 426                 hdr->bestfree[i].offset = 0;
 427         }
 428
 429         /*
 430          * Set up an unused entry for the block's body.
 431          */
 432         dup = (xfs_dir2_data_unused_t *)(hdr + 1);
 433         dup->freetag = cpu_to_be16(XFS_DIR2_DATA_FREE_TAG);
 434
 435         t = mp->m_dirblksize - (uint)sizeof(*hdr);
 436         hdr->bestfree[0].length = cpu_to_be16(t);
 437         dup->length = cpu_to_be16(t);
 438         *xfs_dir2_data_unused_tag_p(dup) = cpu_to_be16((char *)dup - (char *)hdr);
 439         /*
 440          * Log it and return it.
 441          */
 442         xfs_dir2_data_log_header(tp, bp);
 443         xfs_dir2_data_log_unused(tp, bp, dup);
 444         *bpp = bp;
 445         return 0;
 446 }
 447
 448 /*
 449  * Log an active data entry from the block.
 450  */
 451 void
 452 xfs_dir2_data_log_entry(
 453         xfs_trans_t             *tp,            /* transaction pointer */
 454         xfs_dabuf_t             *bp,            /* block buffer */
 455         xfs_dir2_data_entry_t   *dep)           /* data entry pointer */
 456 {
 457         xfs_dir2_data_hdr_t     *hdr = bp->data;
 458
 459         ASSERT(hdr->magic == cpu_to_be32(XFS_DIR2_DATA_MAGIC) ||
 460                hdr->magic == cpu_to_be32(XFS_DIR2_BLOCK_MAGIC));
 461
 462         xfs_da_log_buf(tp, bp, (uint)((char *)dep - (char *)hdr),
 463                 (uint)((char *)(xfs_dir2_data_entry_tag_p(dep) + 1) -
 464                        (char *)hdr - 1));
 465 }
 466
 467 /*
 468  * Log a data block header.
 469  */
 470 void
 471 xfs_dir2_data_log_header(
 472         xfs_trans_t             *tp,            /* transaction pointer */
 473         xfs_dabuf_t             *bp)            /* block buffer */
 474 {
 475         xfs_dir2_data_hdr_t     *hdr = bp->data;
 476
 477         ASSERT(hdr->magic == cpu_to_be32(XFS_DIR2_DATA_MAGIC) ||
 478                hdr->magic == cpu_to_be32(XFS_DIR2_BLOCK_MAGIC));
 479
 480         xfs_da_log_buf(tp, bp, 0, sizeof(*hdr) - 1);
 481 }
 482
 483 /*
 484  * Log a data unused entry.
 485  */
 486 void
 487 xfs_dir2_data_log_unused(
 488         xfs_trans_t             *tp,            /* transaction pointer */
 489         xfs_dabuf_t             *bp,            /* block buffer */
 490         xfs_dir2_data_unused_t  *dup)           /* data unused pointer */
 491 {
 492         xfs_dir2_data_hdr_t     *hdr = bp->data;
 493
 494         ASSERT(hdr->magic == cpu_to_be32(XFS_DIR2_DATA_MAGIC) ||
 495                hdr->magic == cpu_to_be32(XFS_DIR2_BLOCK_MAGIC));
 496
 497         /*
 498          * Log the first part of the unused entry.
 499          */
 500         xfs_da_log_buf(tp, bp, (uint)((char *)dup - (char *)hdr),
 501                 (uint)((char *)&dup->length + sizeof(dup->length) -
 502                        1 - (char *)hdr));
 503         /*
 504          * Log the end (tag) of the unused entry.
 505          */
 506         xfs_da_log_buf(tp, bp,
 507                 (uint)((char *)xfs_dir2_data_unused_tag_p(dup) - (char *)hdr),
 508                 (uint)((char *)xfs_dir2_data_unused_tag_p(dup) - (char *)hdr +
 509                        sizeof(xfs_dir2_data_off_t) - 1));
 510 }
 511
 512 /*
 513  * Make a byte range in the data block unused.
 514  * Its current contents are unimportant.
 515  */
 516 void
 517 xfs_dir2_data_make_free(
 518         xfs_trans_t             *tp,            /* transaction pointer */
 519         xfs_dabuf_t             *bp,            /* block buffer */
 520         xfs_dir2_data_aoff_t    offset,         /* starting byte offset */
 521         xfs_dir2_data_aoff_t    len,            /* length in bytes */
 522         int                     *needlogp,      /* out: log header */
 523         int                     *needscanp)     /* out: regen bestfree */
 524 {
 525         xfs_dir2_data_hdr_t     *hdr;           /* data block pointer */
 526         xfs_dir2_data_free_t    *dfp;           /* bestfree pointer */
 527         char                    *endptr;        /* end of data area */
 528         xfs_mount_t             *mp;            /* filesystem mount point */
 529         int                     needscan;       /* need to regen bestfree */
 530         xfs_dir2_data_unused_t  *newdup;        /* new unused entry */
 531         xfs_dir2_data_unused_t  *postdup;       /* unused entry after us */
 532         xfs_dir2_data_unused_t  *prevdup;       /* unused entry before us */
 533
 534         mp = tp->t_mountp;
 535         hdr = bp->data;
 536
 537         /*
 538          * Figure out where the end of the data area is.
 539          */
 540         if (hdr->magic == cpu_to_be32(XFS_DIR2_DATA_MAGIC))
 541                 endptr = (char *)hdr + mp->m_dirblksize;
 542         else {
 543                 xfs_dir2_block_tail_t   *btp;   /* block tail */
 544
 545                 ASSERT(hdr->magic == cpu_to_be32(XFS_DIR2_BLOCK_MAGIC));
 546                 btp = xfs_dir2_block_tail_p(mp, hdr);
 547                 endptr = (char *)xfs_dir2_block_leaf_p(btp);
 548         }
 549         /*
 550          * If this isn't the start of the block, then back up to
 551          * the previous entry and see if it's free.
 552          */
 553         if (offset > sizeof(*hdr)) {
 554                 __be16                  *tagp;  /* tag just before us */
 555
 556                 tagp = (__be16 *)((char *)hdr + offset) - 1;
 557                 prevdup = (xfs_dir2_data_unused_t *)((char *)hdr + be16_to_cpu(*tagp));
 558                 if (be16_to_cpu(prevdup->freetag) != XFS_DIR2_DATA_FREE_TAG)
 559                         prevdup = NULL;
 560         } else
 561                 prevdup = NULL;
 562         /*
 563          * If this isn't the end of the block, see if the entry after
 564          * us is free.
 565          */
 566         if ((char *)hdr + offset + len < endptr) {
 567                 postdup =
 568                         (xfs_dir2_data_unused_t *)((char *)hdr + offset + len);
 569                 if (be16_to_cpu(postdup->freetag) != XFS_DIR2_DATA_FREE_TAG)
 570                         postdup = NULL;
 571         } else
 572                 postdup = NULL;
 573         ASSERT(*needscanp == 0);
 574         needscan = 0;
 575         /*
 576          * Previous and following entries are both free,
 577          * merge everything into a single free entry.
 578          */
 579         if (prevdup && postdup) {
 580                 xfs_dir2_data_free_t    *dfp2;  /* another bestfree pointer */
 581
 582                 /*
 583                  * See if prevdup and/or postdup are in bestfree table.
 584                  */
 585                 dfp = xfs_dir2_data_freefind(hdr, prevdup);
 586                 dfp2 = xfs_dir2_data_freefind(hdr, postdup);
 587                 /*
 588                  * We need a rescan unless there are exactly 2 free entries
 589                  * namely our two.  Then we know what's happening, otherwise
 590                  * since the third bestfree is there, there might be more
 591                  * entries.
 592                  */
 593                 needscan = (hdr->bestfree[2].length != 0);
 594                 /*
 595                  * Fix up the new big freespace.
 596                  */
 597                 be16_add_cpu(&prevdup->length, len + be16_to_cpu(postdup->length));
 598                 *xfs_dir2_data_unused_tag_p(prevdup) =
 599                         cpu_to_be16((char *)prevdup - (char *)hdr);
 600                 xfs_dir2_data_log_unused(tp, bp, prevdup);
 601                 if (!needscan) {
 602                         /*
 603                          * Has to be the case that entries 0 and 1 are
 604                          * dfp and dfp2 (don't know which is which), and
 605                          * entry 2 is empty.
 606                          * Remove entry 1 first then entry 0.
 607                          */
 608                         ASSERT(dfp && dfp2);
 609                         if (dfp == &hdr->bestfree[1]) {
 610                                 dfp = &hdr->bestfree[0];
 611                                 ASSERT(dfp2 == dfp);
 612                                 dfp2 = &hdr->bestfree[1];
 613                         }
 614                         xfs_dir2_data_freeremove(hdr, dfp2, needlogp);
 615                         xfs_dir2_data_freeremove(hdr, dfp, needlogp);
 616                         /*
 617                          * Now insert the new entry.
 618                          */
 619                         dfp = xfs_dir2_data_freeinsert(hdr, prevdup, needlogp);
 620                         ASSERT(dfp == &hdr->bestfree[0]);
 621                         ASSERT(dfp->length == prevdup->length);
 622                         ASSERT(!dfp[1].length);
 623                         ASSERT(!dfp[2].length);
 624                 }
 625         }
 626         /*
 627          * The entry before us is free, merge with it.
 628          */
 629         else if (prevdup) {
 630                 dfp = xfs_dir2_data_freefind(hdr, prevdup);
 631                 be16_add_cpu(&prevdup->length, len);
 632                 *xfs_dir2_data_unused_tag_p(prevdup) =
 633                         cpu_to_be16((char *)prevdup - (char *)hdr);
 634                 xfs_dir2_data_log_unused(tp, bp, prevdup);
 635                 /*
 636                  * If the previous entry was in the table, the new entry
 637                  * is longer, so it will be in the table too.  Remove
 638                  * the old one and add the new one.
 639                  */
 640                 if (dfp) {
 641                         xfs_dir2_data_freeremove(hdr, dfp, needlogp);
 642                         xfs_dir2_data_freeinsert(hdr, prevdup, needlogp);
 643                 }
 644                 /*
 645                  * Otherwise we need a scan if the new entry is big enough.
 646                  */
 647                 else {
 648                         needscan = be16_to_cpu(prevdup->length) >
 649                                    be16_to_cpu(hdr->bestfree[2].length);
 650                 }
 651         }
 652         /*
 653          * The following entry is free, merge with it.
 654          */
 655         else if (postdup) {
 656                 dfp = xfs_dir2_data_freefind(hdr, postdup);
 657                 newdup = (xfs_dir2_data_unused_t *)((char *)hdr + offset);
 658                 newdup->freetag = cpu_to_be16(XFS_DIR2_DATA_FREE_TAG);
 659                 newdup->length = cpu_to_be16(len + be16_to_cpu(postdup->length));
 660                 *xfs_dir2_data_unused_tag_p(newdup) =
 661                         cpu_to_be16((char *)newdup - (char *)hdr);
 662                 xfs_dir2_data_log_unused(tp, bp, newdup);
 663                 /*
 664                  * If the following entry was in the table, the new entry
 665                  * is longer, so it will be in the table too.  Remove
 666                  * the old one and add the new one.
 667                  */
 668                 if (dfp) {
 669                         xfs_dir2_data_freeremove(hdr, dfp, needlogp);
 670                         xfs_dir2_data_freeinsert(hdr, newdup, needlogp);
 671                 }
 672                 /*
 673                  * Otherwise we need a scan if the new entry is big enough.
 674                  */
 675                 else {
 676                         needscan = be16_to_cpu(newdup->length) >
 677                                    be16_to_cpu(hdr->bestfree[2].length);
 678                 }
 679         }
 680         /*
 681          * Neither neighbor is free.  Make a new entry.
 682          */
 683         else {
 684                 newdup = (xfs_dir2_data_unused_t *)((char *)hdr + offset);
 685                 newdup->freetag = cpu_to_be16(XFS_DIR2_DATA_FREE_TAG);
 686                 newdup->length = cpu_to_be16(len);
 687                 *xfs_dir2_data_unused_tag_p(newdup) =
 688                         cpu_to_be16((char *)newdup - (char *)hdr);
 689                 xfs_dir2_data_log_unused(tp, bp, newdup);
 690                 xfs_dir2_data_freeinsert(hdr, newdup, needlogp);
 691         }
 692         *needscanp = needscan;
 693 }
 694
 695 /*
 696  * Take a byte range out of an existing unused space and make it un-free.
 697  */
 698 void
 699 xfs_dir2_data_use_free(
 700         xfs_trans_t             *tp,            /* transaction pointer */
 701         xfs_dabuf_t             *bp,            /* data block buffer */
 702         xfs_dir2_data_unused_t  *dup,           /* unused entry */
 703         xfs_dir2_data_aoff_t    offset,         /* starting offset to use */
 704         xfs_dir2_data_aoff_t    len,            /* length to use */
 705         int                     *needlogp,      /* out: need to log header */
 706         int                     *needscanp)     /* out: need regen bestfree */
 707 {
 708         xfs_dir2_data_hdr_t     *hdr;           /* data block header */
 709         xfs_dir2_data_free_t    *dfp;           /* bestfree pointer */
 710         int                     matchback;      /* matches end of freespace */
 711         int                     matchfront;     /* matches start of freespace */
 712         int                     needscan;       /* need to regen bestfree */
 713         xfs_dir2_data_unused_t  *newdup;        /* new unused entry */
 714         xfs_dir2_data_unused_t  *newdup2;       /* another new unused entry */
 715         int                     oldlen;         /* old unused entry's length */
 716
 717         hdr = bp->data;
 718         ASSERT(hdr->magic == cpu_to_be32(XFS_DIR2_DATA_MAGIC) ||
 719                hdr->magic == cpu_to_be32(XFS_DIR2_BLOCK_MAGIC));
 720         ASSERT(be16_to_cpu(dup->freetag) == XFS_DIR2_DATA_FREE_TAG);
 721         ASSERT(offset >= (char *)dup - (char *)hdr);
 722         ASSERT(offset + len <= (char *)dup + be16_to_cpu(dup->length) - (char *)hdr);
 723         ASSERT((char *)dup - (char *)hdr == be16_to_cpu(*xfs_dir2_data_unused_tag_p(dup)));
 724         /*
 725          * Look up the entry in the bestfree table.
 726          */
 727         dfp = xfs_dir2_data_freefind(hdr, dup);
 728         oldlen = be16_to_cpu(dup->length);
 729         ASSERT(dfp || oldlen <= be16_to_cpu(hdr->bestfree[2].length));
 730         /*
 731          * Check for alignment with front and back of the entry.
 732          */
 733         matchfront = (char *)dup - (char *)hdr == offset;
 734         matchback = (char *)dup + oldlen - (char *)hdr == offset + len;
 735         ASSERT(*needscanp == 0);
 736         needscan = 0;
 737         /*
 738          * If we matched it exactly we just need to get rid of it from
 739          * the bestfree table.
 740          */
 741         if (matchfront && matchback) {
 742                 if (dfp) {
 743                         needscan = (hdr->bestfree[2].offset != 0);
 744                         if (!needscan)
 745                                 xfs_dir2_data_freeremove(hdr, dfp, needlogp);
 746                 }
 747         }
 748         /*
 749          * We match the first part of the entry.
 750          * Make a new entry with the remaining freespace.
 751          */
 752         else if (matchfront) {
 753                 newdup = (xfs_dir2_data_unused_t *)((char *)hdr + offset + len);
 754                 newdup->freetag = cpu_to_be16(XFS_DIR2_DATA_FREE_TAG);
 755                 newdup->length = cpu_to_be16(oldlen - len);
 756                 *xfs_dir2_data_unused_tag_p(newdup) =
 757                         cpu_to_be16((char *)newdup - (char *)hdr);
 758                 xfs_dir2_data_log_unused(tp, bp, newdup);
 759                 /*
 760                  * If it was in the table, remove it and add the new one.
 761                  */
 762                 if (dfp) {
 763                         xfs_dir2_data_freeremove(hdr, dfp, needlogp);
 764                         dfp = xfs_dir2_data_freeinsert(hdr, newdup, needlogp);
 765                         ASSERT(dfp != NULL);
 766                         ASSERT(dfp->length == newdup->length);
 767                         ASSERT(be16_to_cpu(dfp->offset) == (char *)newdup - (char *)hdr);
 768                         /*
 769                          * If we got inserted at the last slot,
 770                          * that means we don't know if there was a better
 771                          * choice for the last slot, or not.  Rescan.
 772                          */
 773                         needscan = dfp == &hdr->bestfree[2];
 774                 }
 775         }
 776         /*
 777          * We match the last part of the entry.
 778          * Trim the allocated space off the tail of the entry.
 779          */
 780         else if (matchback) {
 781                 newdup = dup;
 782                 newdup->length = cpu_to_be16(((char *)hdr + offset) - (char *)newdup);
 783                 *xfs_dir2_data_unused_tag_p(newdup) =
 784                         cpu_to_be16((char *)newdup - (char *)hdr);
 785                 xfs_dir2_data_log_unused(tp, bp, newdup);
 786                 /*
 787                  * If it was in the table, remove it and add the new one.
 788                  */
 789                 if (dfp) {
 790                         xfs_dir2_data_freeremove(hdr, dfp, needlogp);
 791                         dfp = xfs_dir2_data_freeinsert(hdr, newdup, needlogp);
 792                         ASSERT(dfp != NULL);
 793                         ASSERT(dfp->length == newdup->length);
 794                         ASSERT(be16_to_cpu(dfp->offset) == (char *)newdup - (char *)hdr);
 795                         /*
 796                          * If we got inserted at the last slot,
 797                          * that means we don't know if there was a better
 798                          * choice for the last slot, or not.  Rescan.
 799                          */
 800                         needscan = dfp == &hdr->bestfree[2];
 801                 }
 802         }
 803         /*
 804          * Poking out the middle of an entry.
 805          * Make two new entries.
 806          */
 807         else {
 808                 newdup = dup;
 809                 newdup->length = cpu_to_be16(((char *)hdr + offset) - (char *)newdup);
 810                 *xfs_dir2_data_unused_tag_p(newdup) =
 811                         cpu_to_be16((char *)newdup - (char *)hdr);
 812                 xfs_dir2_data_log_unused(tp, bp, newdup);
 813                 newdup2 = (xfs_dir2_data_unused_t *)((char *)hdr + offset + len);
 814                 newdup2->freetag = cpu_to_be16(XFS_DIR2_DATA_FREE_TAG);
 815                 newdup2->length = cpu_to_be16(oldlen - len - be16_to_cpu(newdup->length));
 816                 *xfs_dir2_data_unused_tag_p(newdup2) =
 817                         cpu_to_be16((char *)newdup2 - (char *)hdr);
 818                 xfs_dir2_data_log_unused(tp, bp, newdup2);
 819                 /*
 820                  * If the old entry was in the table, we need to scan
 821                  * if the 3rd entry was valid, since these entries
 822                  * are smaller than the old one.
 823                  * If we don't need to scan that means there were 1 or 2
 824                  * entries in the table, and removing the old and adding
 825                  * the 2 new will work.
 826                  */
 827                 if (dfp) {
 828                         needscan = (hdr->bestfree[2].length != 0);
 829                         if (!needscan) {
 830                                 xfs_dir2_data_freeremove(hdr, dfp, needlogp);
 831                                 xfs_dir2_data_freeinsert(hdr, newdup, needlogp);
 832                                 xfs_dir2_data_freeinsert(hdr, newdup2,
 833                                                          needlogp);
 834                         }
 835                 }
 836         }
 837         *needscanp = needscan;
 838 }