kernel/fs/xfs/libxfs/xfs_dir2_data.c

   1 /*
   2  * Copyright (c) 2000-2002,2005 Silicon Graphics, Inc.
   3  * Copyright (c) 2013 Red Hat, Inc.
   4  * All Rights Reserved.
   5  *
   6  * This program is free software; you can redistribute it and/or
   7  * modify it under the terms of the GNU General Public License as
   8  * published by the Free Software Foundation.
   9  *
  10  * This program is distributed in the hope that it would be useful,
  11  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  12  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  13  * GNU General Public License for more details.
  14  *
  15  * You should have received a copy of the GNU General Public License
  16  * along with this program; if not, write the Free Software Foundation,
  17  * Inc.,  51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
  18  */
  19 #include "xfs.h"
  20 #include "xfs_fs.h"
  21 #include "xfs_format.h"
  22 #include "xfs_log_format.h"
  23 #include "xfs_trans_resv.h"
  24 #include "xfs_mount.h"
  25 #include "xfs_da_format.h"
  26 #include "xfs_da_btree.h"
  27 #include "xfs_inode.h"
  28 #include "xfs_dir2.h"
  29 #include "xfs_dir2_priv.h"
  30 #include "xfs_error.h"
  31 #include "xfs_trans.h"
  32 #include "xfs_buf_item.h"
  33 #include "xfs_cksum.h"
  34
  35 /*
  36  * Check the consistency of the data block.
  37  * The input can also be a block-format directory.
  38  * Return 0 is the buffer is good, otherwise an error.
  39  */
  40 int
  41 __xfs_dir3_data_check(
  42         struct xfs_inode        *dp,            /* incore inode pointer */
  43         struct xfs_buf          *bp)            /* data block's buffer */
  44 {
  45         xfs_dir2_dataptr_t      addr;           /* addr for leaf lookup */
  46         xfs_dir2_data_free_t    *bf;            /* bestfree table */
  47         xfs_dir2_block_tail_t   *btp=NULL;      /* block tail */
  48         int                     count;          /* count of entries found */
  49         xfs_dir2_data_hdr_t     *hdr;           /* data block header */
  50         xfs_dir2_data_entry_t   *dep;           /* data entry */
  51         xfs_dir2_data_free_t    *dfp;           /* bestfree entry */
  52         xfs_dir2_data_unused_t  *dup;           /* unused entry */
  53         char                    *endp;          /* end of useful data */
  54         int                     freeseen;       /* mask of bestfrees seen */
  55         xfs_dahash_t            hash;           /* hash of current name */
  56         int                     i;              /* leaf index */
  57         int                     lastfree;       /* last entry was unused */
  58         xfs_dir2_leaf_entry_t   *lep=NULL;      /* block leaf entries */
  59         xfs_mount_t             *mp;            /* filesystem mount point */
  60         char                    *p;             /* current data position */
  61         int                     stale;          /* count of stale leaves */
  62         struct xfs_name         name;
  63         const struct xfs_dir_ops *ops;
  64         struct xfs_da_geometry  *geo;
  65
  66         mp = bp->b_target->bt_mount;
  67         geo = mp->m_dir_geo;
  68
  69         /*
  70          * We can be passed a null dp here from a verifier, so we need to go the
  71          * hard way to get them.
  72          */
  73         ops = xfs_dir_get_ops(mp, dp);
  74
  75         hdr = bp->b_addr;
  76         p = (char *)ops->data_entry_p(hdr);
  77
  78         switch (hdr->magic) {
  79         case cpu_to_be32(XFS_DIR3_BLOCK_MAGIC):
  80         case cpu_to_be32(XFS_DIR2_BLOCK_MAGIC):
  81                 btp = xfs_dir2_block_tail_p(geo, hdr);
  82                 lep = xfs_dir2_block_leaf_p(btp);
  83                 endp = (char *)lep;
  84
  85                 /*
  86                  * The number of leaf entries is limited by the size of the
  87                  * block and the amount of space used by the data entries.
  88                  * We don't know how much space is used by the data entries yet,
  89                  * so just ensure that the count falls somewhere inside the
  90                  * block right now.
  91                  */
  92                 XFS_WANT_CORRUPTED_RETURN(mp, be32_to_cpu(btp->count) <
  93                         ((char *)btp - p) / sizeof(struct xfs_dir2_leaf_entry));
  94                 break;
  95         case cpu_to_be32(XFS_DIR3_DATA_MAGIC):
  96         case cpu_to_be32(XFS_DIR2_DATA_MAGIC):
  97                 endp = (char *)hdr + geo->blksize;
  98                 break;
  99         default:
 100                 XFS_ERROR_REPORT("Bad Magic", XFS_ERRLEVEL_LOW, mp);
 101                 return -EFSCORRUPTED;
 102         }
 103
 104         /*
 105          * Account for zero bestfree entries.
 106          */
 107         bf = ops->data_bestfree_p(hdr);
 108         count = lastfree = freeseen = 0;
 109         if (!bf[0].length) {
 110                 XFS_WANT_CORRUPTED_RETURN(mp, !bf[0].offset);
 111                 freeseen |= 1 << 0;
 112         }
 113         if (!bf[1].length) {
 114                 XFS_WANT_CORRUPTED_RETURN(mp, !bf[1].offset);
 115                 freeseen |= 1 << 1;
 116         }
 117         if (!bf[2].length) {
 118                 XFS_WANT_CORRUPTED_RETURN(mp, !bf[2].offset);
 119                 freeseen |= 1 << 2;
 120         }
 121
 122         XFS_WANT_CORRUPTED_RETURN(mp, be16_to_cpu(bf[0].length) >=
 123                                                 be16_to_cpu(bf[1].length));
 124         XFS_WANT_CORRUPTED_RETURN(mp, be16_to_cpu(bf[1].length) >=
 125                                                 be16_to_cpu(bf[2].length));
 126         /*
 127          * Loop over the data/unused entries.
 128          */
 129         while (p < endp) {
 130                 dup = (xfs_dir2_data_unused_t *)p;
 131                 /*
 132                  * If it's unused, look for the space in the bestfree table.
 133                  * If we find it, account for that, else make sure it
 134                  * doesn't need to be there.
 135                  */
 136                 if (be16_to_cpu(dup->freetag) == XFS_DIR2_DATA_FREE_TAG) {
 137                         XFS_WANT_CORRUPTED_RETURN(mp, lastfree == 0);
 138                         XFS_WANT_CORRUPTED_RETURN(mp,
 139                                 be16_to_cpu(*xfs_dir2_data_unused_tag_p(dup)) ==
 140                                                (char *)dup - (char *)hdr);
 141                         dfp = xfs_dir2_data_freefind(hdr, bf, dup);
 142                         if (dfp) {
 143                                 i = (int)(dfp - bf);
 144                                 XFS_WANT_CORRUPTED_RETURN(mp,
 145                                         (freeseen & (1 << i)) == 0);
 146                                 freeseen |= 1 << i;
 147                         } else {
 148                                 XFS_WANT_CORRUPTED_RETURN(mp,
 149                                         be16_to_cpu(dup->length) <=
 150                                                 be16_to_cpu(bf[2].length));
 151                         }
 152                         p += be16_to_cpu(dup->length);
 153                         lastfree = 1;
 154                         continue;
 155                 }
 156                 /*
 157                  * It's a real entry.  Validate the fields.
 158                  * If this is a block directory then make sure it's
 159                  * in the leaf section of the block.
 160                  * The linear search is crude but this is DEBUG code.
 161                  */
 162                 dep = (xfs_dir2_data_entry_t *)p;
 163                 XFS_WANT_CORRUPTED_RETURN(mp, dep->namelen != 0);
 164                 XFS_WANT_CORRUPTED_RETURN(mp,
 165                         !xfs_dir_ino_validate(mp, be64_to_cpu(dep->inumber)));
 166                 XFS_WANT_CORRUPTED_RETURN(mp,
 167                         be16_to_cpu(*ops->data_entry_tag_p(dep)) ==
 168                                                (char *)dep - (char *)hdr);
 169                 XFS_WANT_CORRUPTED_RETURN(mp,
 170                                 ops->data_get_ftype(dep) < XFS_DIR3_FT_MAX);
 171                 count++;
 172                 lastfree = 0;
 173                 if (hdr->magic == cpu_to_be32(XFS_DIR2_BLOCK_MAGIC) ||
 174                     hdr->magic == cpu_to_be32(XFS_DIR3_BLOCK_MAGIC)) {
 175                         addr = xfs_dir2_db_off_to_dataptr(geo, geo->datablk,
 176                                                 (xfs_dir2_data_aoff_t)
 177                                                 ((char *)dep - (char *)hdr));
 178                         name.name = dep->name;
 179                         name.len = dep->namelen;
 180                         hash = mp->m_dirnameops->hashname(&name);
 181                         for (i = 0; i < be32_to_cpu(btp->count); i++) {
 182                                 if (be32_to_cpu(lep[i].address) == addr &&
 183                                     be32_to_cpu(lep[i].hashval) == hash)
 184                                         break;
 185                         }
 186                         XFS_WANT_CORRUPTED_RETURN(mp,
 187                                                   i < be32_to_cpu(btp->count));
 188                 }
 189                 p += ops->data_entsize(dep->namelen);
 190         }
 191         /*
 192          * Need to have seen all the entries and all the bestfree slots.
 193          */
 194         XFS_WANT_CORRUPTED_RETURN(mp, freeseen == 7);
 195         if (hdr->magic == cpu_to_be32(XFS_DIR2_BLOCK_MAGIC) ||
 196             hdr->magic == cpu_to_be32(XFS_DIR3_BLOCK_MAGIC)) {
 197                 for (i = stale = 0; i < be32_to_cpu(btp->count); i++) {
 198                         if (lep[i].address ==
 199                             cpu_to_be32(XFS_DIR2_NULL_DATAPTR))
 200                                 stale++;
 201                         if (i > 0)
 202                                 XFS_WANT_CORRUPTED_RETURN(mp,
 203                                         be32_to_cpu(lep[i].hashval) >=
 204                                                 be32_to_cpu(lep[i - 1].hashval));
 205                 }
 206                 XFS_WANT_CORRUPTED_RETURN(mp, count ==
 207                         be32_to_cpu(btp->count) - be32_to_cpu(btp->stale));
 208                 XFS_WANT_CORRUPTED_RETURN(mp, stale == be32_to_cpu(btp->stale));
 209         }
 210         return 0;
 211 }
 212
 213 static bool
 214 xfs_dir3_data_verify(
 215         struct xfs_buf          *bp)
 216 {
 217         struct xfs_mount        *mp = bp->b_target->bt_mount;
 218         struct xfs_dir3_blk_hdr *hdr3 = bp->b_addr;
 219
 220         if (xfs_sb_version_hascrc(&mp->m_sb)) {
 221                 if (hdr3->magic != cpu_to_be32(XFS_DIR3_DATA_MAGIC))
 222                         return false;
 223                 if (!uuid_equal(&hdr3->uuid, &mp->m_sb.sb_uuid))
 224                         return false;
 225                 if (be64_to_cpu(hdr3->blkno) != bp->b_bn)
 226                         return false;
 227         } else {
 228                 if (hdr3->magic != cpu_to_be32(XFS_DIR2_DATA_MAGIC))
 229                         return false;
 230         }
 231         if (__xfs_dir3_data_check(NULL, bp))
 232                 return false;
 233         return true;
 234 }
 235
 236 /*
 237  * Readahead of the first block of the directory when it is opened is completely
 238  * oblivious to the format of the directory. Hence we can either get a block
 239  * format buffer or a data format buffer on readahead.
 240  */
 241 static void
 242 xfs_dir3_data_reada_verify(
 243         struct xfs_buf          *bp)
 244 {
 245         struct xfs_dir2_data_hdr *hdr = bp->b_addr;
 246
 247         switch (hdr->magic) {
 248         case cpu_to_be32(XFS_DIR2_BLOCK_MAGIC):
 249         case cpu_to_be32(XFS_DIR3_BLOCK_MAGIC):
 250                 bp->b_ops = &xfs_dir3_block_buf_ops;
 251                 bp->b_ops->verify_read(bp);
 252                 return;
 253         case cpu_to_be32(XFS_DIR2_DATA_MAGIC):
 254         case cpu_to_be32(XFS_DIR3_DATA_MAGIC):
 255                 bp->b_ops = &xfs_dir3_data_buf_ops;
 256                 bp->b_ops->verify_read(bp);
 257                 return;
 258         default:
 259                 xfs_buf_ioerror(bp, -EFSCORRUPTED);
 260                 xfs_verifier_error(bp);
 261                 break;
 262         }
 263 }
 264
 265 static void
 266 xfs_dir3_data_read_verify(
 267         struct xfs_buf  *bp)
 268 {
 269         struct xfs_mount        *mp = bp->b_target->bt_mount;
 270
 271         if (xfs_sb_version_hascrc(&mp->m_sb) &&
 272              !xfs_buf_verify_cksum(bp, XFS_DIR3_DATA_CRC_OFF))
 273                  xfs_buf_ioerror(bp, -EFSBADCRC);
 274         else if (!xfs_dir3_data_verify(bp))
 275                 xfs_buf_ioerror(bp, -EFSCORRUPTED);
 276
 277         if (bp->b_error)
 278                 xfs_verifier_error(bp);
 279 }
 280
 281 static void
 282 xfs_dir3_data_write_verify(
 283         struct xfs_buf  *bp)
 284 {
 285         struct xfs_mount        *mp = bp->b_target->bt_mount;
 286         struct xfs_buf_log_item *bip = bp->b_fspriv;
 287         struct xfs_dir3_blk_hdr *hdr3 = bp->b_addr;
 288
 289         if (!xfs_dir3_data_verify(bp)) {
 290                 xfs_buf_ioerror(bp, -EFSCORRUPTED);
 291                 xfs_verifier_error(bp);
 292                 return;
 293         }
 294
 295         if (!xfs_sb_version_hascrc(&mp->m_sb))
 296                 return;
 297
 298         if (bip)
 299                 hdr3->lsn = cpu_to_be64(bip->bli_item.li_lsn);
 300
 301         xfs_buf_update_cksum(bp, XFS_DIR3_DATA_CRC_OFF);
 302 }
 303
 304 const struct xfs_buf_ops xfs_dir3_data_buf_ops = {
 305         .verify_read = xfs_dir3_data_read_verify,
 306         .verify_write = xfs_dir3_data_write_verify,
 307 };
 308
 309 static const struct xfs_buf_ops xfs_dir3_data_reada_buf_ops = {
 310         .verify_read = xfs_dir3_data_reada_verify,
 311         .verify_write = xfs_dir3_data_write_verify,
 312 };
 313
 314
 315 int
 316 xfs_dir3_data_read(
 317         struct xfs_trans        *tp,
 318         struct xfs_inode        *dp,
 319         xfs_dablk_t             bno,
 320         xfs_daddr_t             mapped_bno,
 321         struct xfs_buf          **bpp)
 322 {
 323         int                     err;
 324
 325         err = xfs_da_read_buf(tp, dp, bno, mapped_bno, bpp,
 326                                 XFS_DATA_FORK, &xfs_dir3_data_buf_ops);
 327         if (!err && tp)
 328                 xfs_trans_buf_set_type(tp, *bpp, XFS_BLFT_DIR_DATA_BUF);
 329         return err;
 330 }
 331
 332 int
 333 xfs_dir3_data_readahead(
 334         struct xfs_inode        *dp,
 335         xfs_dablk_t             bno,
 336         xfs_daddr_t             mapped_bno)
 337 {
 338         return xfs_da_reada_buf(dp, bno, mapped_bno,
 339                                 XFS_DATA_FORK, &xfs_dir3_data_reada_buf_ops);
 340 }
 341
 342 /*
 343  * Given a data block and an unused entry from that block,
 344  * return the bestfree entry if any that corresponds to it.
 345  */
 346 xfs_dir2_data_free_t *
 347 xfs_dir2_data_freefind(
 348         struct xfs_dir2_data_hdr *hdr,          /* data block header */
 349         struct xfs_dir2_data_free *bf,          /* bestfree table pointer */
 350         struct xfs_dir2_data_unused *dup)       /* unused space */
 351 {
 352         xfs_dir2_data_free_t    *dfp;           /* bestfree entry */
 353         xfs_dir2_data_aoff_t    off;            /* offset value needed */
 354 #ifdef DEBUG
 355         int                     matched;        /* matched the value */
 356         int                     seenzero;       /* saw a 0 bestfree entry */
 357 #endif
 358
 359         off = (xfs_dir2_data_aoff_t)((char *)dup - (char *)hdr);
 360
 361 #ifdef DEBUG
 362         /*
 363          * Validate some consistency in the bestfree table.
 364          * Check order, non-overlapping entries, and if we find the
 365          * one we're looking for it has to be exact.
 366          */
 367         ASSERT(hdr->magic == cpu_to_be32(XFS_DIR2_DATA_MAGIC) ||
 368                hdr->magic == cpu_to_be32(XFS_DIR3_DATA_MAGIC) ||
 369                hdr->magic == cpu_to_be32(XFS_DIR2_BLOCK_MAGIC) ||
 370                hdr->magic == cpu_to_be32(XFS_DIR3_BLOCK_MAGIC));
 371         for (dfp = &bf[0], seenzero = matched = 0;
 372              dfp < &bf[XFS_DIR2_DATA_FD_COUNT];
 373              dfp++) {
 374                 if (!dfp->offset) {
 375                         ASSERT(!dfp->length);
 376                         seenzero = 1;
 377                         continue;
 378                 }
 379                 ASSERT(seenzero == 0);
 380                 if (be16_to_cpu(dfp->offset) == off) {
 381                         matched = 1;
 382                         ASSERT(dfp->length == dup->length);
 383                 } else if (off < be16_to_cpu(dfp->offset))
 384                         ASSERT(off + be16_to_cpu(dup->length) <= be16_to_cpu(dfp->offset));
 385                 else
 386                         ASSERT(be16_to_cpu(dfp->offset) + be16_to_cpu(dfp->length) <= off);
 387                 ASSERT(matched || be16_to_cpu(dfp->length) >= be16_to_cpu(dup->length));
 388                 if (dfp > &bf[0])
 389                         ASSERT(be16_to_cpu(dfp[-1].length) >= be16_to_cpu(dfp[0].length));
 390         }
 391 #endif
 392         /*
 393          * If this is smaller than the smallest bestfree entry,
 394          * it can't be there since they're sorted.
 395          */
 396         if (be16_to_cpu(dup->length) <
 397             be16_to_cpu(bf[XFS_DIR2_DATA_FD_COUNT - 1].length))
 398                 return NULL;
 399         /*
 400          * Look at the three bestfree entries for our guy.
 401          */
 402         for (dfp = &bf[0]; dfp < &bf[XFS_DIR2_DATA_FD_COUNT]; dfp++) {
 403                 if (!dfp->offset)
 404                         return NULL;
 405                 if (be16_to_cpu(dfp->offset) == off)
 406                         return dfp;
 407         }
 408         /*
 409          * Didn't find it.  This only happens if there are duplicate lengths.
 410          */
 411         return NULL;
 412 }
 413
 414 /*
 415  * Insert an unused-space entry into the bestfree table.
 416  */
 417 xfs_dir2_data_free_t *                          /* entry inserted */
 418 xfs_dir2_data_freeinsert(
 419         struct xfs_dir2_data_hdr *hdr,          /* data block pointer */
 420         struct xfs_dir2_data_free *dfp,         /* bestfree table pointer */
 421         struct xfs_dir2_data_unused *dup,       /* unused space */
 422         int                     *loghead)       /* log the data header (out) */
 423 {
 424         xfs_dir2_data_free_t    new;            /* new bestfree entry */
 425
 426         ASSERT(hdr->magic == cpu_to_be32(XFS_DIR2_DATA_MAGIC) ||
 427                hdr->magic == cpu_to_be32(XFS_DIR2_BLOCK_MAGIC) ||
 428                hdr->magic == cpu_to_be32(XFS_DIR3_DATA_MAGIC) ||
 429                hdr->magic == cpu_to_be32(XFS_DIR3_BLOCK_MAGIC));
 430
 431         new.length = dup->length;
 432         new.offset = cpu_to_be16((char *)dup - (char *)hdr);
 433
 434         /*
 435          * Insert at position 0, 1, or 2; or not at all.
 436          */
 437         if (be16_to_cpu(new.length) > be16_to_cpu(dfp[0].length)) {
 438                 dfp[2] = dfp[1];
 439                 dfp[1] = dfp[0];
 440                 dfp[0] = new;
 441                 *loghead = 1;
 442                 return &dfp[0];
 443         }
 444         if (be16_to_cpu(new.length) > be16_to_cpu(dfp[1].length)) {
 445                 dfp[2] = dfp[1];
 446                 dfp[1] = new;
 447                 *loghead = 1;
 448                 return &dfp[1];
 449         }
 450         if (be16_to_cpu(new.length) > be16_to_cpu(dfp[2].length)) {
 451                 dfp[2] = new;
 452                 *loghead = 1;
 453                 return &dfp[2];
 454         }
 455         return NULL;
 456 }
 457
 458 /*
 459  * Remove a bestfree entry from the table.
 460  */
 461 STATIC void
 462 xfs_dir2_data_freeremove(
 463         struct xfs_dir2_data_hdr *hdr,          /* data block header */
 464         struct xfs_dir2_data_free *bf,          /* bestfree table pointer */
 465         struct xfs_dir2_data_free *dfp,         /* bestfree entry pointer */
 466         int                     *loghead)       /* out: log data header */
 467 {
 468
 469         ASSERT(hdr->magic == cpu_to_be32(XFS_DIR2_DATA_MAGIC) ||
 470                hdr->magic == cpu_to_be32(XFS_DIR2_BLOCK_MAGIC) ||
 471                hdr->magic == cpu_to_be32(XFS_DIR3_DATA_MAGIC) ||
 472                hdr->magic == cpu_to_be32(XFS_DIR3_BLOCK_MAGIC));
 473
 474         /*
 475          * It's the first entry, slide the next 2 up.
 476          */
 477         if (dfp == &bf[0]) {
 478                 bf[0] = bf[1];
 479                 bf[1] = bf[2];
 480         }
 481         /*
 482          * It's the second entry, slide the 3rd entry up.
 483          */
 484         else if (dfp == &bf[1])
 485                 bf[1] = bf[2];
 486         /*
 487          * Must be the last entry.
 488          */
 489         else
 490                 ASSERT(dfp == &bf[2]);
 491         /*
 492          * Clear the 3rd entry, must be zero now.
 493          */
 494         bf[2].length = 0;
 495         bf[2].offset = 0;
 496         *loghead = 1;
 497 }
 498
 499 /*
 500  * Given a data block, reconstruct its bestfree map.
 501  */
 502 void
 503 xfs_dir2_data_freescan(
 504         struct xfs_inode        *dp,
 505         struct xfs_dir2_data_hdr *hdr,
 506         int                     *loghead)
 507 {
 508         xfs_dir2_block_tail_t   *btp;           /* block tail */
 509         xfs_dir2_data_entry_t   *dep;           /* active data entry */
 510         xfs_dir2_data_unused_t  *dup;           /* unused data entry */
 511         struct xfs_dir2_data_free *bf;
 512         char                    *endp;          /* end of block's data */
 513         char                    *p;             /* current entry pointer */
 514         struct xfs_da_geometry  *geo = dp->i_mount->m_dir_geo;
 515
 516         ASSERT(hdr->magic == cpu_to_be32(XFS_DIR2_DATA_MAGIC) ||
 517                hdr->magic == cpu_to_be32(XFS_DIR3_DATA_MAGIC) ||
 518                hdr->magic == cpu_to_be32(XFS_DIR2_BLOCK_MAGIC) ||
 519                hdr->magic == cpu_to_be32(XFS_DIR3_BLOCK_MAGIC));
 520
 521         /*
 522          * Start by clearing the table.
 523          */
 524         bf = dp->d_ops->data_bestfree_p(hdr);
 525         memset(bf, 0, sizeof(*bf) * XFS_DIR2_DATA_FD_COUNT);
 526         *loghead = 1;
 527         /*
 528          * Set up pointers.
 529          */
 530         p = (char *)dp->d_ops->data_entry_p(hdr);
 531         if (hdr->magic == cpu_to_be32(XFS_DIR2_BLOCK_MAGIC) ||
 532             hdr->magic == cpu_to_be32(XFS_DIR3_BLOCK_MAGIC)) {
 533                 btp = xfs_dir2_block_tail_p(geo, hdr);
 534                 endp = (char *)xfs_dir2_block_leaf_p(btp);
 535         } else
 536                 endp = (char *)hdr + geo->blksize;
 537         /*
 538          * Loop over the block's entries.
 539          */
 540         while (p < endp) {
 541                 dup = (xfs_dir2_data_unused_t *)p;
 542                 /*
 543                  * If it's a free entry, insert it.
 544                  */
 545                 if (be16_to_cpu(dup->freetag) == XFS_DIR2_DATA_FREE_TAG) {
 546                         ASSERT((char *)dup - (char *)hdr ==
 547                                be16_to_cpu(*xfs_dir2_data_unused_tag_p(dup)));
 548                         xfs_dir2_data_freeinsert(hdr, bf, dup, loghead);
 549                         p += be16_to_cpu(dup->length);
 550                 }
 551                 /*
 552                  * For active entries, check their tags and skip them.
 553                  */
 554                 else {
 555                         dep = (xfs_dir2_data_entry_t *)p;
 556                         ASSERT((char *)dep - (char *)hdr ==
 557                                be16_to_cpu(*dp->d_ops->data_entry_tag_p(dep)));
 558                         p += dp->d_ops->data_entsize(dep->namelen);
 559                 }
 560         }
 561 }
 562
 563 /*
 564  * Initialize a data block at the given block number in the directory.
 565  * Give back the buffer for the created block.
 566  */
 567 int                                             /* error */
 568 xfs_dir3_data_init(
 569         xfs_da_args_t           *args,          /* directory operation args */
 570         xfs_dir2_db_t           blkno,          /* logical dir block number */
 571         struct xfs_buf          **bpp)          /* output block buffer */
 572 {
 573         struct xfs_buf          *bp;            /* block buffer */
 574         xfs_dir2_data_hdr_t     *hdr;           /* data block header */
 575         xfs_inode_t             *dp;            /* incore directory inode */
 576         xfs_dir2_data_unused_t  *dup;           /* unused entry pointer */
 577         struct xfs_dir2_data_free *bf;
 578         int                     error;          /* error return value */
 579         int                     i;              /* bestfree index */
 580         xfs_mount_t             *mp;            /* filesystem mount point */
 581         xfs_trans_t             *tp;            /* transaction pointer */
 582         int                     t;              /* temp */
 583
 584         dp = args->dp;
 585         mp = dp->i_mount;
 586         tp = args->trans;
 587         /*
 588          * Get the buffer set up for the block.
 589          */
 590         error = xfs_da_get_buf(tp, dp, xfs_dir2_db_to_da(args->geo, blkno),
 591                                -1, &bp, XFS_DATA_FORK);
 592         if (error)
 593                 return error;
 594         bp->b_ops = &xfs_dir3_data_buf_ops;
 595         xfs_trans_buf_set_type(tp, bp, XFS_BLFT_DIR_DATA_BUF);
 596
 597         /*
 598          * Initialize the header.
 599          */
 600         hdr = bp->b_addr;
 601         if (xfs_sb_version_hascrc(&mp->m_sb)) {
 602                 struct xfs_dir3_blk_hdr *hdr3 = bp->b_addr;
 603
 604                 memset(hdr3, 0, sizeof(*hdr3));
 605                 hdr3->magic = cpu_to_be32(XFS_DIR3_DATA_MAGIC);
 606                 hdr3->blkno = cpu_to_be64(bp->b_bn);
 607                 hdr3->owner = cpu_to_be64(dp->i_ino);
 608                 uuid_copy(&hdr3->uuid, &mp->m_sb.sb_uuid);
 609
 610         } else
 611                 hdr->magic = cpu_to_be32(XFS_DIR2_DATA_MAGIC);
 612
 613         bf = dp->d_ops->data_bestfree_p(hdr);
 614         bf[0].offset = cpu_to_be16(dp->d_ops->data_entry_offset);
 615         for (i = 1; i < XFS_DIR2_DATA_FD_COUNT; i++) {
 616                 bf[i].length = 0;
 617                 bf[i].offset = 0;
 618         }
 619
 620         /*
 621          * Set up an unused entry for the block's body.
 622          */
 623         dup = dp->d_ops->data_unused_p(hdr);
 624         dup->freetag = cpu_to_be16(XFS_DIR2_DATA_FREE_TAG);
 625
 626         t = args->geo->blksize - (uint)dp->d_ops->data_entry_offset;
 627         bf[0].length = cpu_to_be16(t);
 628         dup->length = cpu_to_be16(t);
 629         *xfs_dir2_data_unused_tag_p(dup) = cpu_to_be16((char *)dup - (char *)hdr);
 630         /*
 631          * Log it and return it.
 632          */
 633         xfs_dir2_data_log_header(args, bp);
 634         xfs_dir2_data_log_unused(args, bp, dup);
 635         *bpp = bp;
 636         return 0;
 637 }
 638
 639 /*
 640  * Log an active data entry from the block.
 641  */
 642 void
 643 xfs_dir2_data_log_entry(
 644         struct xfs_da_args      *args,
 645         struct xfs_buf          *bp,
 646         xfs_dir2_data_entry_t   *dep)           /* data entry pointer */
 647 {
 648         struct xfs_dir2_data_hdr *hdr = bp->b_addr;
 649
 650         ASSERT(hdr->magic == cpu_to_be32(XFS_DIR2_DATA_MAGIC) ||
 651                hdr->magic == cpu_to_be32(XFS_DIR3_DATA_MAGIC) ||
 652                hdr->magic == cpu_to_be32(XFS_DIR2_BLOCK_MAGIC) ||
 653                hdr->magic == cpu_to_be32(XFS_DIR3_BLOCK_MAGIC));
 654
 655         xfs_trans_log_buf(args->trans, bp, (uint)((char *)dep - (char *)hdr),
 656                 (uint)((char *)(args->dp->d_ops->data_entry_tag_p(dep) + 1) -
 657                        (char *)hdr - 1));
 658 }
 659
 660 /*
 661  * Log a data block header.
 662  */
 663 void
 664 xfs_dir2_data_log_header(
 665         struct xfs_da_args      *args,
 666         struct xfs_buf          *bp)
 667 {
 668 #ifdef DEBUG
 669         struct xfs_dir2_data_hdr *hdr = bp->b_addr;
 670
 671         ASSERT(hdr->magic == cpu_to_be32(XFS_DIR2_DATA_MAGIC) ||
 672                hdr->magic == cpu_to_be32(XFS_DIR3_DATA_MAGIC) ||
 673                hdr->magic == cpu_to_be32(XFS_DIR2_BLOCK_MAGIC) ||
 674                hdr->magic == cpu_to_be32(XFS_DIR3_BLOCK_MAGIC));
 675 #endif
 676
 677         xfs_trans_log_buf(args->trans, bp, 0,
 678                           args->dp->d_ops->data_entry_offset - 1);
 679 }
 680
 681 /*
 682  * Log a data unused entry.
 683  */
 684 void
 685 xfs_dir2_data_log_unused(
 686         struct xfs_da_args      *args,
 687         struct xfs_buf          *bp,
 688         xfs_dir2_data_unused_t  *dup)           /* data unused pointer */
 689 {
 690         xfs_dir2_data_hdr_t     *hdr = bp->b_addr;
 691
 692         ASSERT(hdr->magic == cpu_to_be32(XFS_DIR2_DATA_MAGIC) ||
 693                hdr->magic == cpu_to_be32(XFS_DIR3_DATA_MAGIC) ||
 694                hdr->magic == cpu_to_be32(XFS_DIR2_BLOCK_MAGIC) ||
 695                hdr->magic == cpu_to_be32(XFS_DIR3_BLOCK_MAGIC));
 696
 697         /*
 698          * Log the first part of the unused entry.
 699          */
 700         xfs_trans_log_buf(args->trans, bp, (uint)((char *)dup - (char *)hdr),
 701                 (uint)((char *)&dup->length + sizeof(dup->length) -
 702                        1 - (char *)hdr));
 703         /*
 704          * Log the end (tag) of the unused entry.
 705          */
 706         xfs_trans_log_buf(args->trans, bp,
 707                 (uint)((char *)xfs_dir2_data_unused_tag_p(dup) - (char *)hdr),
 708                 (uint)((char *)xfs_dir2_data_unused_tag_p(dup) - (char *)hdr +
 709                        sizeof(xfs_dir2_data_off_t) - 1));
 710 }
 711
 712 /*
 713  * Make a byte range in the data block unused.
 714  * Its current contents are unimportant.
 715  */
 716 void
 717 xfs_dir2_data_make_free(
 718         struct xfs_da_args      *args,
 719         struct xfs_buf          *bp,
 720         xfs_dir2_data_aoff_t    offset,         /* starting byte offset */
 721         xfs_dir2_data_aoff_t    len,            /* length in bytes */
 722         int                     *needlogp,      /* out: log header */
 723         int                     *needscanp)     /* out: regen bestfree */
 724 {
 725         xfs_dir2_data_hdr_t     *hdr;           /* data block pointer */
 726         xfs_dir2_data_free_t    *dfp;           /* bestfree pointer */
 727         char                    *endptr;        /* end of data area */
 728         int                     needscan;       /* need to regen bestfree */
 729         xfs_dir2_data_unused_t  *newdup;        /* new unused entry */
 730         xfs_dir2_data_unused_t  *postdup;       /* unused entry after us */
 731         xfs_dir2_data_unused_t  *prevdup;       /* unused entry before us */
 732         struct xfs_dir2_data_free *bf;
 733
 734         hdr = bp->b_addr;
 735
 736         /*
 737          * Figure out where the end of the data area is.
 738          */
 739         if (hdr->magic == cpu_to_be32(XFS_DIR2_DATA_MAGIC) ||
 740             hdr->magic == cpu_to_be32(XFS_DIR3_DATA_MAGIC))
 741                 endptr = (char *)hdr + args->geo->blksize;
 742         else {
 743                 xfs_dir2_block_tail_t   *btp;   /* block tail */
 744
 745                 ASSERT(hdr->magic == cpu_to_be32(XFS_DIR2_BLOCK_MAGIC) ||
 746                         hdr->magic == cpu_to_be32(XFS_DIR3_BLOCK_MAGIC));
 747                 btp = xfs_dir2_block_tail_p(args->geo, hdr);
 748                 endptr = (char *)xfs_dir2_block_leaf_p(btp);
 749         }
 750         /*
 751          * If this isn't the start of the block, then back up to
 752          * the previous entry and see if it's free.
 753          */
 754         if (offset > args->dp->d_ops->data_entry_offset) {
 755                 __be16                  *tagp;  /* tag just before us */
 756
 757                 tagp = (__be16 *)((char *)hdr + offset) - 1;
 758                 prevdup = (xfs_dir2_data_unused_t *)((char *)hdr + be16_to_cpu(*tagp));
 759                 if (be16_to_cpu(prevdup->freetag) != XFS_DIR2_DATA_FREE_TAG)
 760                         prevdup = NULL;
 761         } else
 762                 prevdup = NULL;
 763         /*
 764          * If this isn't the end of the block, see if the entry after
 765          * us is free.
 766          */
 767         if ((char *)hdr + offset + len < endptr) {
 768                 postdup =
 769                         (xfs_dir2_data_unused_t *)((char *)hdr + offset + len);
 770                 if (be16_to_cpu(postdup->freetag) != XFS_DIR2_DATA_FREE_TAG)
 771                         postdup = NULL;
 772         } else
 773                 postdup = NULL;
 774         ASSERT(*needscanp == 0);
 775         needscan = 0;
 776         /*
 777          * Previous and following entries are both free,
 778          * merge everything into a single free entry.
 779          */
 780         bf = args->dp->d_ops->data_bestfree_p(hdr);
 781         if (prevdup && postdup) {
 782                 xfs_dir2_data_free_t    *dfp2;  /* another bestfree pointer */
 783
 784                 /*
 785                  * See if prevdup and/or postdup are in bestfree table.
 786                  */
 787                 dfp = xfs_dir2_data_freefind(hdr, bf, prevdup);
 788                 dfp2 = xfs_dir2_data_freefind(hdr, bf, postdup);
 789                 /*
 790                  * We need a rescan unless there are exactly 2 free entries
 791                  * namely our two.  Then we know what's happening, otherwise
 792                  * since the third bestfree is there, there might be more
 793                  * entries.
 794                  */
 795                 needscan = (bf[2].length != 0);
 796                 /*
 797                  * Fix up the new big freespace.
 798                  */
 799                 be16_add_cpu(&prevdup->length, len + be16_to_cpu(postdup->length));
 800                 *xfs_dir2_data_unused_tag_p(prevdup) =
 801                         cpu_to_be16((char *)prevdup - (char *)hdr);
 802                 xfs_dir2_data_log_unused(args, bp, prevdup);
 803                 if (!needscan) {
 804                         /*
 805                          * Has to be the case that entries 0 and 1 are
 806                          * dfp and dfp2 (don't know which is which), and
 807                          * entry 2 is empty.
 808                          * Remove entry 1 first then entry 0.
 809                          */
 810                         ASSERT(dfp && dfp2);
 811                         if (dfp == &bf[1]) {
 812                                 dfp = &bf[0];
 813                                 ASSERT(dfp2 == dfp);
 814                                 dfp2 = &bf[1];
 815                         }
 816                         xfs_dir2_data_freeremove(hdr, bf, dfp2, needlogp);
 817                         xfs_dir2_data_freeremove(hdr, bf, dfp, needlogp);
 818                         /*
 819                          * Now insert the new entry.
 820                          */
 821                         dfp = xfs_dir2_data_freeinsert(hdr, bf, prevdup,
 822                                                        needlogp);
 823                         ASSERT(dfp == &bf[0]);
 824                         ASSERT(dfp->length == prevdup->length);
 825                         ASSERT(!dfp[1].length);
 826                         ASSERT(!dfp[2].length);
 827                 }
 828         }
 829         /*
 830          * The entry before us is free, merge with it.
 831          */
 832         else if (prevdup) {
 833                 dfp = xfs_dir2_data_freefind(hdr, bf, prevdup);
 834                 be16_add_cpu(&prevdup->length, len);
 835                 *xfs_dir2_data_unused_tag_p(prevdup) =
 836                         cpu_to_be16((char *)prevdup - (char *)hdr);
 837                 xfs_dir2_data_log_unused(args, bp, prevdup);
 838                 /*
 839                  * If the previous entry was in the table, the new entry
 840                  * is longer, so it will be in the table too.  Remove
 841                  * the old one and add the new one.
 842                  */
 843                 if (dfp) {
 844                         xfs_dir2_data_freeremove(hdr, bf, dfp, needlogp);
 845                         xfs_dir2_data_freeinsert(hdr, bf, prevdup, needlogp);
 846                 }
 847                 /*
 848                  * Otherwise we need a scan if the new entry is big enough.
 849                  */
 850                 else {
 851                         needscan = be16_to_cpu(prevdup->length) >
 852                                    be16_to_cpu(bf[2].length);
 853                 }
 854         }
 855         /*
 856          * The following entry is free, merge with it.
 857          */
 858         else if (postdup) {
 859                 dfp = xfs_dir2_data_freefind(hdr, bf, postdup);
 860                 newdup = (xfs_dir2_data_unused_t *)((char *)hdr + offset);
 861                 newdup->freetag = cpu_to_be16(XFS_DIR2_DATA_FREE_TAG);
 862                 newdup->length = cpu_to_be16(len + be16_to_cpu(postdup->length));
 863                 *xfs_dir2_data_unused_tag_p(newdup) =
 864                         cpu_to_be16((char *)newdup - (char *)hdr);
 865                 xfs_dir2_data_log_unused(args, bp, newdup);
 866                 /*
 867                  * If the following entry was in the table, the new entry
 868                  * is longer, so it will be in the table too.  Remove
 869                  * the old one and add the new one.
 870                  */
 871                 if (dfp) {
 872                         xfs_dir2_data_freeremove(hdr, bf, dfp, needlogp);
 873                         xfs_dir2_data_freeinsert(hdr, bf, newdup, needlogp);
 874                 }
 875                 /*
 876                  * Otherwise we need a scan if the new entry is big enough.
 877                  */
 878                 else {
 879                         needscan = be16_to_cpu(newdup->length) >
 880                                    be16_to_cpu(bf[2].length);
 881                 }
 882         }
 883         /*
 884          * Neither neighbor is free.  Make a new entry.
 885          */
 886         else {
 887                 newdup = (xfs_dir2_data_unused_t *)((char *)hdr + offset);
 888                 newdup->freetag = cpu_to_be16(XFS_DIR2_DATA_FREE_TAG);
 889                 newdup->length = cpu_to_be16(len);
 890                 *xfs_dir2_data_unused_tag_p(newdup) =
 891                         cpu_to_be16((char *)newdup - (char *)hdr);
 892                 xfs_dir2_data_log_unused(args, bp, newdup);
 893                 xfs_dir2_data_freeinsert(hdr, bf, newdup, needlogp);
 894         }
 895         *needscanp = needscan;
 896 }
 897
 898 /*
 899  * Take a byte range out of an existing unused space and make it un-free.
 900  */
 901 void
 902 xfs_dir2_data_use_free(
 903         struct xfs_da_args      *args,
 904         struct xfs_buf          *bp,
 905         xfs_dir2_data_unused_t  *dup,           /* unused entry */
 906         xfs_dir2_data_aoff_t    offset,         /* starting offset to use */
 907         xfs_dir2_data_aoff_t    len,            /* length to use */
 908         int                     *needlogp,      /* out: need to log header */
 909         int                     *needscanp)     /* out: need regen bestfree */
 910 {
 911         xfs_dir2_data_hdr_t     *hdr;           /* data block header */
 912         xfs_dir2_data_free_t    *dfp;           /* bestfree pointer */
 913         int                     matchback;      /* matches end of freespace */
 914         int                     matchfront;     /* matches start of freespace */
 915         int                     needscan;       /* need to regen bestfree */
 916         xfs_dir2_data_unused_t  *newdup;        /* new unused entry */
 917         xfs_dir2_data_unused_t  *newdup2;       /* another new unused entry */
 918         int                     oldlen;         /* old unused entry's length */
 919         struct xfs_dir2_data_free *bf;
 920
 921         hdr = bp->b_addr;
 922         ASSERT(hdr->magic == cpu_to_be32(XFS_DIR2_DATA_MAGIC) ||
 923                hdr->magic == cpu_to_be32(XFS_DIR3_DATA_MAGIC) ||
 924                hdr->magic == cpu_to_be32(XFS_DIR2_BLOCK_MAGIC) ||
 925                hdr->magic == cpu_to_be32(XFS_DIR3_BLOCK_MAGIC));
 926         ASSERT(be16_to_cpu(dup->freetag) == XFS_DIR2_DATA_FREE_TAG);
 927         ASSERT(offset >= (char *)dup - (char *)hdr);
 928         ASSERT(offset + len <= (char *)dup + be16_to_cpu(dup->length) - (char *)hdr);
 929         ASSERT((char *)dup - (char *)hdr == be16_to_cpu(*xfs_dir2_data_unused_tag_p(dup)));
 930         /*
 931          * Look up the entry in the bestfree table.
 932          */
 933         oldlen = be16_to_cpu(dup->length);
 934         bf = args->dp->d_ops->data_bestfree_p(hdr);
 935         dfp = xfs_dir2_data_freefind(hdr, bf, dup);
 936         ASSERT(dfp || oldlen <= be16_to_cpu(bf[2].length));
 937         /*
 938          * Check for alignment with front and back of the entry.
 939          */
 940         matchfront = (char *)dup - (char *)hdr == offset;
 941         matchback = (char *)dup + oldlen - (char *)hdr == offset + len;
 942         ASSERT(*needscanp == 0);
 943         needscan = 0;
 944         /*
 945          * If we matched it exactly we just need to get rid of it from
 946          * the bestfree table.
 947          */
 948         if (matchfront && matchback) {
 949                 if (dfp) {
 950                         needscan = (bf[2].offset != 0);
 951                         if (!needscan)
 952                                 xfs_dir2_data_freeremove(hdr, bf, dfp,
 953                                                          needlogp);
 954                 }
 955         }
 956         /*
 957          * We match the first part of the entry.
 958          * Make a new entry with the remaining freespace.
 959          */
 960         else if (matchfront) {
 961                 newdup = (xfs_dir2_data_unused_t *)((char *)hdr + offset + len);
 962                 newdup->freetag = cpu_to_be16(XFS_DIR2_DATA_FREE_TAG);
 963                 newdup->length = cpu_to_be16(oldlen - len);
 964                 *xfs_dir2_data_unused_tag_p(newdup) =
 965                         cpu_to_be16((char *)newdup - (char *)hdr);
 966                 xfs_dir2_data_log_unused(args, bp, newdup);
 967                 /*
 968                  * If it was in the table, remove it and add the new one.
 969                  */
 970                 if (dfp) {
 971                         xfs_dir2_data_freeremove(hdr, bf, dfp, needlogp);
 972                         dfp = xfs_dir2_data_freeinsert(hdr, bf, newdup,
 973                                                        needlogp);
 974                         ASSERT(dfp != NULL);
 975                         ASSERT(dfp->length == newdup->length);
 976                         ASSERT(be16_to_cpu(dfp->offset) == (char *)newdup - (char *)hdr);
 977                         /*
 978                          * If we got inserted at the last slot,
 979                          * that means we don't know if there was a better
 980                          * choice for the last slot, or not.  Rescan.
 981                          */
 982                         needscan = dfp == &bf[2];
 983                 }
 984         }
 985         /*
 986          * We match the last part of the entry.
 987          * Trim the allocated space off the tail of the entry.
 988          */
 989         else if (matchback) {
 990                 newdup = dup;
 991                 newdup->length = cpu_to_be16(((char *)hdr + offset) - (char *)newdup);
 992                 *xfs_dir2_data_unused_tag_p(newdup) =
 993                         cpu_to_be16((char *)newdup - (char *)hdr);
 994                 xfs_dir2_data_log_unused(args, bp, newdup);
 995                 /*
 996                  * If it was in the table, remove it and add the new one.
 997                  */
 998                 if (dfp) {
 999                         xfs_dir2_data_freeremove(hdr, bf, dfp, needlogp);
1000                         dfp = xfs_dir2_data_freeinsert(hdr, bf, newdup,
1001                                                        needlogp);
1002                         ASSERT(dfp != NULL);
1003                         ASSERT(dfp->length == newdup->length);
1004                         ASSERT(be16_to_cpu(dfp->offset) == (char *)newdup - (char *)hdr);
1005                         /*
1006                          * If we got inserted at the last slot,
1007                          * that means we don't know if there was a better
1008                          * choice for the last slot, or not.  Rescan.
1009                          */
1010                         needscan = dfp == &bf[2];
1011                 }
1012         }
1013         /*
1014          * Poking out the middle of an entry.
1015          * Make two new entries.
1016          */
1017         else {
1018                 newdup = dup;
1019                 newdup->length = cpu_to_be16(((char *)hdr + offset) - (char *)newdup);
1020                 *xfs_dir2_data_unused_tag_p(newdup) =
1021                         cpu_to_be16((char *)newdup - (char *)hdr);
1022                 xfs_dir2_data_log_unused(args, bp, newdup);
1023                 newdup2 = (xfs_dir2_data_unused_t *)((char *)hdr + offset + len);
1024                 newdup2->freetag = cpu_to_be16(XFS_DIR2_DATA_FREE_TAG);
1025                 newdup2->length = cpu_to_be16(oldlen - len - be16_to_cpu(newdup->length));
1026                 *xfs_dir2_data_unused_tag_p(newdup2) =
1027                         cpu_to_be16((char *)newdup2 - (char *)hdr);
1028                 xfs_dir2_data_log_unused(args, bp, newdup2);
1029                 /*
1030                  * If the old entry was in the table, we need to scan
1031                  * if the 3rd entry was valid, since these entries
1032                  * are smaller than the old one.
1033                  * If we don't need to scan that means there were 1 or 2
1034                  * entries in the table, and removing the old and adding
1035                  * the 2 new will work.
1036                  */
1037                 if (dfp) {
1038                         needscan = (bf[2].length != 0);
1039                         if (!needscan) {
1040                                 xfs_dir2_data_freeremove(hdr, bf, dfp,
1041                                                          needlogp);
1042                                 xfs_dir2_data_freeinsert(hdr, bf, newdup,
1043                                                          needlogp);
1044                                 xfs_dir2_data_freeinsert(hdr, bf, newdup2,
1045                                                          needlogp);
1046                         }
1047                 }
1048         }
1049         *needscanp = needscan;
1050 }