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