Pileus Git - ~andy/linux/blob - fs/xfs/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_sb.h"
  25 #include "xfs_ag.h"
  26 #include "xfs_mount.h"
  27 #include "xfs_da_format.h"
  28 #include "xfs_da_btree.h"
  29 #include "xfs_inode.h"
  30 #include "xfs_dir2.h"
  31 #include "xfs_dir2_priv.h"
  32 #include "xfs_error.h"
  33 #include "xfs_trans.h"
  34 #include "xfs_buf_item.h"
  35 #include "xfs_cksum.h"
  36
  37 /*
  38  * Check the consistency of the data block.
  39  * The input can also be a block-format directory.
  40  * Return 0 is the buffer is good, otherwise an error.
  41  */
  42 int
  43 __xfs_dir3_data_check(
  44         struct xfs_inode        *dp,            /* incore inode pointer */
  45         struct xfs_buf          *bp)            /* data block's buffer */
  46 {
  47         xfs_dir2_dataptr_t      addr;           /* addr for leaf lookup */
  48         xfs_dir2_data_free_t    *bf;            /* bestfree table */
  49         xfs_dir2_block_tail_t   *btp=NULL;      /* block tail */
  50         int                     count;          /* count of entries found */
  51         xfs_dir2_data_hdr_t     *hdr;           /* data block header */
  52         xfs_dir2_data_entry_t   *dep;           /* data entry */
  53         xfs_dir2_data_free_t    *dfp;           /* bestfree entry */
  54         xfs_dir2_data_unused_t  *dup;           /* unused entry */
  55         char                    *endp;          /* end of useful data */
  56         int                     freeseen;       /* mask of bestfrees seen */
  57         xfs_dahash_t            hash;           /* hash of current name */
  58         int                     i;              /* leaf index */
  59         int                     lastfree;       /* last entry was unused */
  60         xfs_dir2_leaf_entry_t   *lep=NULL;      /* block leaf entries */
  61         xfs_mount_t             *mp;            /* filesystem mount point */
  62         char                    *p;             /* current data position */
  63         int                     stale;          /* count of stale leaves */
  64         struct xfs_name         name;
  65         const struct xfs_dir_ops *ops;
  66
  67         mp = bp->b_target->bt_mount;
  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(mp, 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 + mp->m_dirblksize;
  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(mp, mp->m_dirdatablk,
 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_mount        *mp = bp->b_target->bt_mount;
 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                 xfs_dir3_data_verify(bp);
 256                 return;
 257         default:
 258                 XFS_CORRUPTION_ERROR(__func__, XFS_ERRLEVEL_LOW, mp, hdr);
 259                 xfs_buf_ioerror(bp, EFSCORRUPTED);
 260                 break;
 261         }
 262 }
 263
 264 static void
 265 xfs_dir3_data_read_verify(
 266         struct xfs_buf  *bp)
 267 {
 268         struct xfs_mount        *mp = bp->b_target->bt_mount;
 269
 270         if ((xfs_sb_version_hascrc(&mp->m_sb) &&
 271              !xfs_verify_cksum(bp->b_addr, BBTOB(bp->b_length),
 272                                           XFS_DIR3_DATA_CRC_OFF)) ||
 273             !xfs_dir3_data_verify(bp)) {
 274                 XFS_CORRUPTION_ERROR(__func__, XFS_ERRLEVEL_LOW, mp, bp->b_addr);
 275                 xfs_buf_ioerror(bp, EFSCORRUPTED);
 276         }
 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_CORRUPTION_ERROR(__func__, XFS_ERRLEVEL_LOW, mp, bp->b_addr);
 289                 xfs_buf_ioerror(bp, EFSCORRUPTED);
 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_update_cksum(bp->b_addr, BBTOB(bp->b_length), 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_trans        *tp,
 333         struct xfs_inode        *dp,
 334         xfs_dablk_t             bno,
 335         xfs_daddr_t             mapped_bno)
 336 {
 337         return xfs_da_reada_buf(tp, dp, bno, mapped_bno,
 338                                 XFS_DATA_FORK, &xfs_dir3_data_reada_buf_ops);
 339 }
 340
 341 /*
 342  * Given a data block and an unused entry from that block,
 343  * return the bestfree entry if any that corresponds to it.
 344  */
 345 xfs_dir2_data_free_t *
 346 xfs_dir2_data_freefind(
 347         struct xfs_dir2_data_hdr *hdr,          /* data block header */
 348         struct xfs_dir2_data_free *bf,          /* bestfree table pointer */
 349         struct xfs_dir2_data_unused *dup)       /* unused space */
 350 {
 351         xfs_dir2_data_free_t    *dfp;           /* bestfree entry */
 352         xfs_dir2_data_aoff_t    off;            /* offset value needed */
 353 #ifdef DEBUG
 354         int                     matched;        /* matched the value */
 355         int                     seenzero;       /* saw a 0 bestfree entry */
 356 #endif
 357
 358         off = (xfs_dir2_data_aoff_t)((char *)dup - (char *)hdr);
 359
 360 #ifdef DEBUG
 361         /*
 362          * Validate some consistency in the bestfree table.
 363          * Check order, non-overlapping entries, and if we find the
 364          * one we're looking for it has to be exact.
 365          */
 366         ASSERT(hdr->magic == cpu_to_be32(XFS_DIR2_DATA_MAGIC) ||
 367                hdr->magic == cpu_to_be32(XFS_DIR3_DATA_MAGIC) ||
 368                hdr->magic == cpu_to_be32(XFS_DIR2_BLOCK_MAGIC) ||
 369                hdr->magic == cpu_to_be32(XFS_DIR3_BLOCK_MAGIC));
 370         for (dfp = &bf[0], seenzero = matched = 0;
 371              dfp < &bf[XFS_DIR2_DATA_FD_COUNT];
 372              dfp++) {
 373                 if (!dfp->offset) {
 374                         ASSERT(!dfp->length);
 375                         seenzero = 1;
 376                         continue;
 377                 }
 378                 ASSERT(seenzero == 0);
 379                 if (be16_to_cpu(dfp->offset) == off) {
 380                         matched = 1;
 381                         ASSERT(dfp->length == dup->length);
 382                 } else if (off < be16_to_cpu(dfp->offset))
 383                         ASSERT(off + be16_to_cpu(dup->length) <= be16_to_cpu(dfp->offset));
 384                 else
 385                         ASSERT(be16_to_cpu(dfp->offset) + be16_to_cpu(dfp->length) <= off);
 386                 ASSERT(matched || be16_to_cpu(dfp->length) >= be16_to_cpu(dup->length));
 387                 if (dfp > &bf[0])
 388                         ASSERT(be16_to_cpu(dfp[-1].length) >= be16_to_cpu(dfp[0].length));
 389         }
 390 #endif
 391         /*
 392          * If this is smaller than the smallest bestfree entry,
 393          * it can't be there since they're sorted.
 394          */
 395         if (be16_to_cpu(dup->length) <
 396             be16_to_cpu(bf[XFS_DIR2_DATA_FD_COUNT - 1].length))
 397                 return NULL;
 398         /*
 399          * Look at the three bestfree entries for our guy.
 400          */
 401         for (dfp = &bf[0]; dfp < &bf[XFS_DIR2_DATA_FD_COUNT]; dfp++) {
 402                 if (!dfp->offset)
 403                         return NULL;
 404                 if (be16_to_cpu(dfp->offset) == off)
 405                         return dfp;
 406         }
 407         /*
 408          * Didn't find it.  This only happens if there are duplicate lengths.
 409          */
 410         return NULL;
 411 }
 412
 413 /*
 414  * Insert an unused-space entry into the bestfree table.
 415  */
 416 xfs_dir2_data_free_t *                          /* entry inserted */
 417 xfs_dir2_data_freeinsert(
 418         struct xfs_dir2_data_hdr *hdr,          /* data block pointer */
 419         struct xfs_dir2_data_free *dfp,         /* bestfree table pointer */
 420         struct xfs_dir2_data_unused *dup,       /* unused space */
 421         int                     *loghead)       /* log the data header (out) */
 422 {
 423         xfs_dir2_data_free_t    new;            /* new bestfree entry */
 424
 425         ASSERT(hdr->magic == cpu_to_be32(XFS_DIR2_DATA_MAGIC) ||
 426                hdr->magic == cpu_to_be32(XFS_DIR2_BLOCK_MAGIC) ||
 427                hdr->magic == cpu_to_be32(XFS_DIR3_DATA_MAGIC) ||
 428                hdr->magic == cpu_to_be32(XFS_DIR3_BLOCK_MAGIC));
 429
 430         new.length = dup->length;
 431         new.offset = cpu_to_be16((char *)dup - (char *)hdr);
 432
 433         /*
 434          * Insert at position 0, 1, or 2; or not at all.
 435          */
 436         if (be16_to_cpu(new.length) > be16_to_cpu(dfp[0].length)) {
 437                 dfp[2] = dfp[1];
 438                 dfp[1] = dfp[0];
 439                 dfp[0] = new;
 440                 *loghead = 1;
 441                 return &dfp[0];
 442         }
 443         if (be16_to_cpu(new.length) > be16_to_cpu(dfp[1].length)) {
 444                 dfp[2] = dfp[1];
 445                 dfp[1] = new;
 446                 *loghead = 1;
 447                 return &dfp[1];
 448         }
 449         if (be16_to_cpu(new.length) > be16_to_cpu(dfp[2].length)) {
 450                 dfp[2] = new;
 451                 *loghead = 1;
 452                 return &dfp[2];
 453         }
 454         return NULL;
 455 }
 456
 457 /*
 458  * Remove a bestfree entry from the table.
 459  */
 460 STATIC void
 461 xfs_dir2_data_freeremove(
 462         struct xfs_dir2_data_hdr *hdr,          /* data block header */
 463         struct xfs_dir2_data_free *bf,          /* bestfree table pointer */
 464         struct xfs_dir2_data_free *dfp,         /* bestfree entry pointer */
 465         int                     *loghead)       /* out: log data header */
 466 {
 467
 468         ASSERT(hdr->magic == cpu_to_be32(XFS_DIR2_DATA_MAGIC) ||
 469                hdr->magic == cpu_to_be32(XFS_DIR2_BLOCK_MAGIC) ||
 470                hdr->magic == cpu_to_be32(XFS_DIR3_DATA_MAGIC) ||
 471                hdr->magic == cpu_to_be32(XFS_DIR3_BLOCK_MAGIC));
 472
 473         /*
 474          * It's the first entry, slide the next 2 up.
 475          */
 476         if (dfp == &bf[0]) {
 477                 bf[0] = bf[1];
 478                 bf[1] = bf[2];
 479         }
 480         /*
 481          * It's the second entry, slide the 3rd entry up.
 482          */
 483         else if (dfp == &bf[1])
 484                 bf[1] = bf[2];
 485         /*
 486          * Must be the last entry.
 487          */
 488         else
 489                 ASSERT(dfp == &bf[2]);
 490         /*
 491          * Clear the 3rd entry, must be zero now.
 492          */
 493         bf[2].length = 0;
 494         bf[2].offset = 0;
 495         *loghead = 1;
 496 }
 497
 498 /*
 499  * Given a data block, reconstruct its bestfree map.
 500  */
 501 void
 502 xfs_dir2_data_freescan(
 503         struct xfs_inode        *dp,
 504         struct xfs_dir2_data_hdr *hdr,
 505         int                     *loghead)
 506 {
 507         xfs_dir2_block_tail_t   *btp;           /* block tail */
 508         xfs_dir2_data_entry_t   *dep;           /* active data entry */
 509         xfs_dir2_data_unused_t  *dup;           /* unused data entry */
 510         struct xfs_dir2_data_free *bf;
 511         char                    *endp;          /* end of block's data */
 512         char                    *p;             /* current entry pointer */
 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(dp->i_mount, hdr);
 532                 endp = (char *)xfs_dir2_block_leaf_p(btp);
 533         } else
 534                 endp = (char *)hdr + dp->i_mount->m_dirblksize;
 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(mp, blkno), -1, &bp,
 589                 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 = mp->m_dirblksize - (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(tp, dp, bp);
 632         xfs_dir2_data_log_unused(tp, 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_trans        *tp,
 643         struct xfs_inode        *dp,
 644         struct xfs_buf          *bp,
 645         xfs_dir2_data_entry_t   *dep)           /* data entry pointer */
 646 {
 647         struct xfs_dir2_data_hdr *hdr = bp->b_addr;
 648
 649         ASSERT(hdr->magic == cpu_to_be32(XFS_DIR2_DATA_MAGIC) ||
 650                hdr->magic == cpu_to_be32(XFS_DIR3_DATA_MAGIC) ||
 651                hdr->magic == cpu_to_be32(XFS_DIR2_BLOCK_MAGIC) ||
 652                hdr->magic == cpu_to_be32(XFS_DIR3_BLOCK_MAGIC));
 653
 654         xfs_trans_log_buf(tp, bp, (uint)((char *)dep - (char *)hdr),
 655                 (uint)((char *)(dp->d_ops->data_entry_tag_p(dep) + 1) -
 656                        (char *)hdr - 1));
 657 }
 658
 659 /*
 660  * Log a data block header.
 661  */
 662 void
 663 xfs_dir2_data_log_header(
 664         struct xfs_trans        *tp,
 665         struct xfs_inode        *dp,
 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(tp, bp, 0, dp->d_ops->data_entry_offset - 1);
 678 }
 679
 680 /*
 681  * Log a data unused entry.
 682  */
 683 void
 684 xfs_dir2_data_log_unused(
 685         struct xfs_trans        *tp,
 686         struct xfs_buf          *bp,
 687         xfs_dir2_data_unused_t  *dup)           /* data unused pointer */
 688 {
 689         xfs_dir2_data_hdr_t     *hdr = bp->b_addr;
 690
 691         ASSERT(hdr->magic == cpu_to_be32(XFS_DIR2_DATA_MAGIC) ||
 692                hdr->magic == cpu_to_be32(XFS_DIR3_DATA_MAGIC) ||
 693                hdr->magic == cpu_to_be32(XFS_DIR2_BLOCK_MAGIC) ||
 694                hdr->magic == cpu_to_be32(XFS_DIR3_BLOCK_MAGIC));
 695
 696         /*
 697          * Log the first part of the unused entry.
 698          */
 699         xfs_trans_log_buf(tp, bp, (uint)((char *)dup - (char *)hdr),
 700                 (uint)((char *)&dup->length + sizeof(dup->length) -
 701                        1 - (char *)hdr));
 702         /*
 703          * Log the end (tag) of the unused entry.
 704          */
 705         xfs_trans_log_buf(tp, bp,
 706                 (uint)((char *)xfs_dir2_data_unused_tag_p(dup) - (char *)hdr),
 707                 (uint)((char *)xfs_dir2_data_unused_tag_p(dup) - (char *)hdr +
 708                        sizeof(xfs_dir2_data_off_t) - 1));
 709 }
 710
 711 /*
 712  * Make a byte range in the data block unused.
 713  * Its current contents are unimportant.
 714  */
 715 void
 716 xfs_dir2_data_make_free(
 717         struct xfs_trans        *tp,
 718         struct xfs_inode        *dp,
 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         xfs_mount_t             *mp;            /* filesystem mount point */
 729         int                     needscan;       /* need to regen bestfree */
 730         xfs_dir2_data_unused_t  *newdup;        /* new unused entry */
 731         xfs_dir2_data_unused_t  *postdup;       /* unused entry after us */
 732         xfs_dir2_data_unused_t  *prevdup;       /* unused entry before us */
 733         struct xfs_dir2_data_free *bf;
 734
 735         mp = tp->t_mountp;
 736         hdr = bp->b_addr;
 737
 738         /*
 739          * Figure out where the end of the data area is.
 740          */
 741         if (hdr->magic == cpu_to_be32(XFS_DIR2_DATA_MAGIC) ||
 742             hdr->magic == cpu_to_be32(XFS_DIR3_DATA_MAGIC))
 743                 endptr = (char *)hdr + mp->m_dirblksize;
 744         else {
 745                 xfs_dir2_block_tail_t   *btp;   /* block tail */
 746
 747                 ASSERT(hdr->magic == cpu_to_be32(XFS_DIR2_BLOCK_MAGIC) ||
 748                         hdr->magic == cpu_to_be32(XFS_DIR3_BLOCK_MAGIC));
 749                 btp = xfs_dir2_block_tail_p(mp, hdr);
 750                 endptr = (char *)xfs_dir2_block_leaf_p(btp);
 751         }
 752         /*
 753          * If this isn't the start of the block, then back up to
 754          * the previous entry and see if it's free.
 755          */
 756         if (offset > dp->d_ops->data_entry_offset) {
 757                 __be16                  *tagp;  /* tag just before us */
 758
 759                 tagp = (__be16 *)((char *)hdr + offset) - 1;
 760                 prevdup = (xfs_dir2_data_unused_t *)((char *)hdr + be16_to_cpu(*tagp));
 761                 if (be16_to_cpu(prevdup->freetag) != XFS_DIR2_DATA_FREE_TAG)
 762                         prevdup = NULL;
 763         } else
 764                 prevdup = NULL;
 765         /*
 766          * If this isn't the end of the block, see if the entry after
 767          * us is free.
 768          */
 769         if ((char *)hdr + offset + len < endptr) {
 770                 postdup =
 771                         (xfs_dir2_data_unused_t *)((char *)hdr + offset + len);
 772                 if (be16_to_cpu(postdup->freetag) != XFS_DIR2_DATA_FREE_TAG)
 773                         postdup = NULL;
 774         } else
 775                 postdup = NULL;
 776         ASSERT(*needscanp == 0);
 777         needscan = 0;
 778         /*
 779          * Previous and following entries are both free,
 780          * merge everything into a single free entry.
 781          */
 782         bf = dp->d_ops->data_bestfree_p(hdr);
 783         if (prevdup && postdup) {
 784                 xfs_dir2_data_free_t    *dfp2;  /* another bestfree pointer */
 785
 786                 /*
 787                  * See if prevdup and/or postdup are in bestfree table.
 788                  */
 789                 dfp = xfs_dir2_data_freefind(hdr, bf, prevdup);
 790                 dfp2 = xfs_dir2_data_freefind(hdr, bf, postdup);
 791                 /*
 792                  * We need a rescan unless there are exactly 2 free entries
 793                  * namely our two.  Then we know what's happening, otherwise
 794                  * since the third bestfree is there, there might be more
 795                  * entries.
 796                  */
 797                 needscan = (bf[2].length != 0);
 798                 /*
 799                  * Fix up the new big freespace.
 800                  */
 801                 be16_add_cpu(&prevdup->length, len + be16_to_cpu(postdup->length));
 802                 *xfs_dir2_data_unused_tag_p(prevdup) =
 803                         cpu_to_be16((char *)prevdup - (char *)hdr);
 804                 xfs_dir2_data_log_unused(tp, bp, prevdup);
 805                 if (!needscan) {
 806                         /*
 807                          * Has to be the case that entries 0 and 1 are
 808                          * dfp and dfp2 (don't know which is which), and
 809                          * entry 2 is empty.
 810                          * Remove entry 1 first then entry 0.
 811                          */
 812                         ASSERT(dfp && dfp2);
 813                         if (dfp == &bf[1]) {
 814                                 dfp = &bf[0];
 815                                 ASSERT(dfp2 == dfp);
 816                                 dfp2 = &bf[1];
 817                         }
 818                         xfs_dir2_data_freeremove(hdr, bf, dfp2, needlogp);
 819                         xfs_dir2_data_freeremove(hdr, bf, dfp, needlogp);
 820                         /*
 821                          * Now insert the new entry.
 822                          */
 823                         dfp = xfs_dir2_data_freeinsert(hdr, bf, prevdup,
 824                                                        needlogp);
 825                         ASSERT(dfp == &bf[0]);
 826                         ASSERT(dfp->length == prevdup->length);
 827                         ASSERT(!dfp[1].length);
 828                         ASSERT(!dfp[2].length);
 829                 }
 830         }
 831         /*
 832          * The entry before us is free, merge with it.
 833          */
 834         else if (prevdup) {
 835                 dfp = xfs_dir2_data_freefind(hdr, bf, prevdup);
 836                 be16_add_cpu(&prevdup->length, len);
 837                 *xfs_dir2_data_unused_tag_p(prevdup) =
 838                         cpu_to_be16((char *)prevdup - (char *)hdr);
 839                 xfs_dir2_data_log_unused(tp, bp, prevdup);
 840                 /*
 841                  * If the previous entry was in the table, the new entry
 842                  * is longer, so it will be in the table too.  Remove
 843                  * the old one and add the new one.
 844                  */
 845                 if (dfp) {
 846                         xfs_dir2_data_freeremove(hdr, bf, dfp, needlogp);
 847                         xfs_dir2_data_freeinsert(hdr, bf, prevdup, needlogp);
 848                 }
 849                 /*
 850                  * Otherwise we need a scan if the new entry is big enough.
 851                  */
 852                 else {
 853                         needscan = be16_to_cpu(prevdup->length) >
 854                                    be16_to_cpu(bf[2].length);
 855                 }
 856         }
 857         /*
 858          * The following entry is free, merge with it.
 859          */
 860         else if (postdup) {
 861                 dfp = xfs_dir2_data_freefind(hdr, bf, postdup);
 862                 newdup = (xfs_dir2_data_unused_t *)((char *)hdr + offset);
 863                 newdup->freetag = cpu_to_be16(XFS_DIR2_DATA_FREE_TAG);
 864                 newdup->length = cpu_to_be16(len + be16_to_cpu(postdup->length));
 865                 *xfs_dir2_data_unused_tag_p(newdup) =
 866                         cpu_to_be16((char *)newdup - (char *)hdr);
 867                 xfs_dir2_data_log_unused(tp, bp, newdup);
 868                 /*
 869                  * If the following entry was in the table, the new entry
 870                  * is longer, so it will be in the table too.  Remove
 871                  * the old one and add the new one.
 872                  */
 873                 if (dfp) {
 874                         xfs_dir2_data_freeremove(hdr, bf, dfp, needlogp);
 875                         xfs_dir2_data_freeinsert(hdr, bf, newdup, needlogp);
 876                 }
 877                 /*
 878                  * Otherwise we need a scan if the new entry is big enough.
 879                  */
 880                 else {
 881                         needscan = be16_to_cpu(newdup->length) >
 882                                    be16_to_cpu(bf[2].length);
 883                 }
 884         }
 885         /*
 886          * Neither neighbor is free.  Make a new entry.
 887          */
 888         else {
 889                 newdup = (xfs_dir2_data_unused_t *)((char *)hdr + offset);
 890                 newdup->freetag = cpu_to_be16(XFS_DIR2_DATA_FREE_TAG);
 891                 newdup->length = cpu_to_be16(len);
 892                 *xfs_dir2_data_unused_tag_p(newdup) =
 893                         cpu_to_be16((char *)newdup - (char *)hdr);
 894                 xfs_dir2_data_log_unused(tp, bp, newdup);
 895                 xfs_dir2_data_freeinsert(hdr, bf, newdup, needlogp);
 896         }
 897         *needscanp = needscan;
 898 }
 899
 900 /*
 901  * Take a byte range out of an existing unused space and make it un-free.
 902  */
 903 void
 904 xfs_dir2_data_use_free(
 905         struct xfs_trans        *tp,
 906         struct xfs_inode        *dp,
 907         struct xfs_buf          *bp,
 908         xfs_dir2_data_unused_t  *dup,           /* unused entry */
 909         xfs_dir2_data_aoff_t    offset,         /* starting offset to use */
 910         xfs_dir2_data_aoff_t    len,            /* length to use */
 911         int                     *needlogp,      /* out: need to log header */
 912         int                     *needscanp)     /* out: need regen bestfree */
 913 {
 914         xfs_dir2_data_hdr_t     *hdr;           /* data block header */
 915         xfs_dir2_data_free_t    *dfp;           /* bestfree pointer */
 916         int                     matchback;      /* matches end of freespace */
 917         int                     matchfront;     /* matches start of freespace */
 918         int                     needscan;       /* need to regen bestfree */
 919         xfs_dir2_data_unused_t  *newdup;        /* new unused entry */
 920         xfs_dir2_data_unused_t  *newdup2;       /* another new unused entry */
 921         int                     oldlen;         /* old unused entry's length */
 922         struct xfs_dir2_data_free *bf;
 923
 924         hdr = bp->b_addr;
 925         ASSERT(hdr->magic == cpu_to_be32(XFS_DIR2_DATA_MAGIC) ||
 926                hdr->magic == cpu_to_be32(XFS_DIR3_DATA_MAGIC) ||
 927                hdr->magic == cpu_to_be32(XFS_DIR2_BLOCK_MAGIC) ||
 928                hdr->magic == cpu_to_be32(XFS_DIR3_BLOCK_MAGIC));
 929         ASSERT(be16_to_cpu(dup->freetag) == XFS_DIR2_DATA_FREE_TAG);
 930         ASSERT(offset >= (char *)dup - (char *)hdr);
 931         ASSERT(offset + len <= (char *)dup + be16_to_cpu(dup->length) - (char *)hdr);
 932         ASSERT((char *)dup - (char *)hdr == be16_to_cpu(*xfs_dir2_data_unused_tag_p(dup)));
 933         /*
 934          * Look up the entry in the bestfree table.
 935          */
 936         oldlen = be16_to_cpu(dup->length);
 937         bf = dp->d_ops->data_bestfree_p(hdr);
 938         dfp = xfs_dir2_data_freefind(hdr, bf, dup);
 939         ASSERT(dfp || oldlen <= be16_to_cpu(bf[2].length));
 940         /*
 941          * Check for alignment with front and back of the entry.
 942          */
 943         matchfront = (char *)dup - (char *)hdr == offset;
 944         matchback = (char *)dup + oldlen - (char *)hdr == offset + len;
 945         ASSERT(*needscanp == 0);
 946         needscan = 0;
 947         /*
 948          * If we matched it exactly we just need to get rid of it from
 949          * the bestfree table.
 950          */
 951         if (matchfront && matchback) {
 952                 if (dfp) {
 953                         needscan = (bf[2].offset != 0);
 954                         if (!needscan)
 955                                 xfs_dir2_data_freeremove(hdr, bf, dfp,
 956                                                          needlogp);
 957                 }
 958         }
 959         /*
 960          * We match the first part of the entry.
 961          * Make a new entry with the remaining freespace.
 962          */
 963         else if (matchfront) {
 964                 newdup = (xfs_dir2_data_unused_t *)((char *)hdr + offset + len);
 965                 newdup->freetag = cpu_to_be16(XFS_DIR2_DATA_FREE_TAG);
 966                 newdup->length = cpu_to_be16(oldlen - len);
 967                 *xfs_dir2_data_unused_tag_p(newdup) =
 968                         cpu_to_be16((char *)newdup - (char *)hdr);
 969                 xfs_dir2_data_log_unused(tp, bp, newdup);
 970                 /*
 971                  * If it was in the table, remove it and add the new one.
 972                  */
 973                 if (dfp) {
 974                         xfs_dir2_data_freeremove(hdr, bf, dfp, needlogp);
 975                         dfp = xfs_dir2_data_freeinsert(hdr, bf, newdup,
 976                                                        needlogp);
 977                         ASSERT(dfp != NULL);
 978                         ASSERT(dfp->length == newdup->length);
 979                         ASSERT(be16_to_cpu(dfp->offset) == (char *)newdup - (char *)hdr);
 980                         /*
 981                          * If we got inserted at the last slot,
 982                          * that means we don't know if there was a better
 983                          * choice for the last slot, or not.  Rescan.
 984                          */
 985                         needscan = dfp == &bf[2];
 986                 }
 987         }
 988         /*
 989          * We match the last part of the entry.
 990          * Trim the allocated space off the tail of the entry.
 991          */
 992         else if (matchback) {
 993                 newdup = dup;
 994                 newdup->length = cpu_to_be16(((char *)hdr + offset) - (char *)newdup);
 995                 *xfs_dir2_data_unused_tag_p(newdup) =
 996                         cpu_to_be16((char *)newdup - (char *)hdr);
 997                 xfs_dir2_data_log_unused(tp, bp, newdup);
 998                 /*
 999                  * If it was in the table, remove it and add the new one.
1000                  */
1001                 if (dfp) {
1002                         xfs_dir2_data_freeremove(hdr, bf, dfp, needlogp);
1003                         dfp = xfs_dir2_data_freeinsert(hdr, bf, newdup,
1004                                                        needlogp);
1005                         ASSERT(dfp != NULL);
1006                         ASSERT(dfp->length == newdup->length);
1007                         ASSERT(be16_to_cpu(dfp->offset) == (char *)newdup - (char *)hdr);
1008                         /*
1009                          * If we got inserted at the last slot,
1010                          * that means we don't know if there was a better
1011                          * choice for the last slot, or not.  Rescan.
1012                          */
1013                         needscan = dfp == &bf[2];
1014                 }
1015         }
1016         /*
1017          * Poking out the middle of an entry.
1018          * Make two new entries.
1019          */
1020         else {
1021                 newdup = dup;
1022                 newdup->length = cpu_to_be16(((char *)hdr + offset) - (char *)newdup);
1023                 *xfs_dir2_data_unused_tag_p(newdup) =
1024                         cpu_to_be16((char *)newdup - (char *)hdr);
1025                 xfs_dir2_data_log_unused(tp, bp, newdup);
1026                 newdup2 = (xfs_dir2_data_unused_t *)((char *)hdr + offset + len);
1027                 newdup2->freetag = cpu_to_be16(XFS_DIR2_DATA_FREE_TAG);
1028                 newdup2->length = cpu_to_be16(oldlen - len - be16_to_cpu(newdup->length));
1029                 *xfs_dir2_data_unused_tag_p(newdup2) =
1030                         cpu_to_be16((char *)newdup2 - (char *)hdr);
1031                 xfs_dir2_data_log_unused(tp, bp, newdup2);
1032                 /*
1033                  * If the old entry was in the table, we need to scan
1034                  * if the 3rd entry was valid, since these entries
1035                  * are smaller than the old one.
1036                  * If we don't need to scan that means there were 1 or 2
1037                  * entries in the table, and removing the old and adding
1038                  * the 2 new will work.
1039                  */
1040                 if (dfp) {
1041                         needscan = (bf[2].length != 0);
1042                         if (!needscan) {
1043                                 xfs_dir2_data_freeremove(hdr, bf, dfp,
1044                                                          needlogp);
1045                                 xfs_dir2_data_freeinsert(hdr, bf, newdup,
1046                                                          needlogp);
1047                                 xfs_dir2_data_freeinsert(hdr, bf, newdup2,
1048                                                          needlogp);
1049                         }
1050                 }
1051         }
1052         *needscanp = needscan;
1053 }